U.S. patent number 3,677,255 [Application Number 05/116,440] was granted by the patent office on 1972-07-18 for electrical ignition system.
This patent grant is currently assigned to Eleanor Burditt Krost. Invention is credited to Donald D. Withem.
United States Patent |
3,677,255 |
Withem |
July 18, 1972 |
ELECTRICAL IGNITION SYSTEM
Abstract
An automotive ignition system in which a storage condenser or
capacitor is charged during the time that the points or contacts
are closed, the condenser or capacitor being charged from a source
of DC energy through a power supply circuit that steps up the
voltage.
Inventors: |
Withem; Donald D. (Chagrin
Falls, OH) |
Assignee: |
Krost; Eleanor Burditt
(N/A)
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Family
ID: |
22367224 |
Appl.
No.: |
05/116,440 |
Filed: |
February 18, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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871672 |
Nov 19, 1969 |
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767915 |
Sep 30, 1968 |
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570845 |
Aug 8, 1966 |
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Current U.S.
Class: |
123/604;
315/209CD |
Current CPC
Class: |
F02P
3/0884 (20130101) |
Current International
Class: |
F02P
3/00 (20060101); F02P 3/08 (20060101); F02p
003/06 () |
Field of
Search: |
;123/148E ;315/209 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Goodridge; Laurence M.
Parent Case Text
This application is a continuation-in-part of my application Ser.
No. 871,672 filed Nov. 19, 1969, which was a continuation of my
application Ser. No. 767,915 filed Sept. 30, 1968, now abandoned,
which in turn was a continuation-in-part of my earlier application
Ser. No. 570,845 filed Aug. 8, 1966, now abandoned.
Claims
What is claimed is:
1. An ignition system for igniting the combustible mixture of an
internal combustion engine and including a source of direct current
and a spark discharge device and comprising in combination, a
transformer having a primary winding and three secondary windings,
namely a first secondary winding, a second secondary winding, and a
third secondary winding, an electronic conductive device having
current carrying output terminal means and having input terminal
means for controlling the conductivity of the path of current flow
between said output terminal means, a first current path including
the path between said output terminal means and said primary
winding connected across the source of direct current to conduct a
flow of current from the source of direct current through said
primary winding, an asymmetrical conductive device poled to conduct
a first induced current flow in said first secondary winding that
opposes the building up of the magnetic field of said transformer
during the time that current from said source of direct current is
flowing in said primary winding, a first capacitor connected to be
charged and discharged in synchronism with the operation of the
engine, a second current path including said first secondary
winding and said asymmetrical conductive device connected in series
across said first capacitor to charge said first capacitor by said
first induced current, first control means connected to said input
terminal means of said electronic conductive device to control the
flow of current from said source of direct current in said primary
winding in synchronism with the operation of the engine and to
cause to be interrupted said latter current flow at substantially
the same time or at a time approaching the same time that said
first capacitor is charged, an electronic switch having current
carrying output terminal means and input terminal means to control
the conductivity of the path between said output terminal means, an
inductance, a second capacitor, discharge means including the path
between said output terminal means of said electronic switch, said
inductance and said second capacitor connected in series across
said first capacitor and said second capacitor also connected in
parallel with said second secondary winding and including said
third secondary winding connected with said spark discharge device
to discharge said first capacitor through said inductance into said
second capacitor thereby causing a voltage on said second capacitor
and said second secondary winding which causes a second induced
current to flow in said third secondary winding to produce a spark
at said spark discharge device, and second control means connected
to the said input terminal means of said electronic switch to
control the conductivity of the path between said output terminal
means in synchronism with the operation of the engine.
2. An ignition system as defined in claim 1 wherein said first
control means and said second control means include in common a
magnetic control device having a primary winding and two secondary
windings, one secondary winding being included in said first
control means and the other secondary winding being included in
said second control means and said magnetic control device being
energized by current from said source of direct current conducted
through said primary winding of said magnetic control device in
synchronism with the operation of the engine.
3. An ignition system as defined in claim 1 wherein said electronic
conductive device is a transistor, said asymmetrical conductive
device is a semi-conductor diode, and said electronic switch is a
thyratron tube.
4. An ignition system as defined in claim 1 wherein said electronic
conductive device is a transistor, said asymmetrical device is a
semi-conductor diode, and said electronic switch is a silicon
controlled rectifier.
5. An ignition system for igniting the combustible mixture of an
internal combustion engine and including a source of direct current
and a spark-discharge device and comprising in combination a
transformer having a primary winding and a secondary winding, a
first inductance, an electronic conductive device having current
carrying output terminal means and input terminal means for
controlling the conductivity between said output terminal means, a
first current path including the path between said output terminal
means, said first inductance, and said primary winding connected in
series across said source of direct current to conduct a flow of
current from said source of direct current in said inductance and
said primary winding, a first capacitor connected to be charged and
discharged in synchronism with the operation of the engine, an
asymmetrical conductive device poled to conduct an induced current
flow in said secondary winding that opposes the building up of the
magnetic field of said transformer during the time that said
current from said source of direct current is flowing in said
inductance and said primary winding, said asymmetrical conductive
device, said secondary winding and said capacitor being connected
in series to charge said first capacitor by said inducted current,
first control means connected across said input terminal means of
said electronic conductive device to control the flow of current
from said source of direct current in said inductance and said
primary winding in synchronism with the operation of the engine and
to cause said latter current to be interrupted at substantially the
same time or at a time approaching the same time that said first
capacitor is charged, an electronic switch having current carrying
output terminal means and input terminal means for controlling the
conductivity of the path between said output terminals, a second
inductance, a second capacitor operatively connected to fire said
spark-discharge device, discharge means including a path provided
by said output terminal means of said electronic switch, said
second inductance, and said second capacitor being connected in
series across said first capacitor to discharge said first
capacitor through said second inductance into said second capacitor
to cause a spark at said spark-discharge device, second control
means connected to the control input terminal means of said
electronic switch to control said discharge means in synchronism
with the operation of the engine, and energy-disposing means
connected to said transformer for disposing of the energy of the
remaining magnetic fields of said transformer and said
inductance.
6. An ignition system as defined in claim 5 wherein said first
control means and said second control means include in common a
magnetic control device having a primary winding and two secondary
windings one secondary winding being included in said first control
means and the other secondary winding being included in said second
control means and said magnetic control device being energized by
current from said source of direct current conducted through said
primary winding of said magnetic control device in synchronism with
the operation of the engine.
7. An ignition system as defined in claim 5 wherein said discharge
means includes a second secondary winding on said transformer
connected across said second capacitor to discharge said second
capacitor through said second secondary winding, and includes a
third secondary winding on said transformer connected with said
spark discharge device to cause a spark at said spark discharge
device by an induced current in said third secondary winding.
8. An ignition system as defined in claim 7 wherein said first
control means and said second control means include in common a
magnetic control device having a primary winding and two secondary
windings, one secondary winding being included in said first
control means and the other secondary winding being included in
said second control means and said magnetic control device being
energized by current from said source of direct current conducted
through said primary winding of said magnetic control device in
synchronism with the operation of the engine.
9. A capacitor charging and discharging system for use in an
ignition system adapted to ignite the combustible mixture of an
internal combustion engine, said ignition system including a source
of direct current, a spark discharge device, synchronizing means,
and an ignition coil operatively connected with said spark
discharge device, comprising in combination, a capacitor; step-up
transformer means including a magnetic core, a primary winding, and
a secondary winding; semiconductor means including output circuit
means and input circuit means to control the conductivity of said
output circuit means; means connected with said input circuit means
to cause said output circuit means to become conductive in
synchronism with the operation of the engine and to remain
conductive until said capacitor is substantially charged; a first
subcombination including said output circuit means and said primary
winding operatively connected in series, said first subcombination
being adapted to be connected across said source of direct current
to permit current to flow in said primary winding when said output
circuit means is conductive; a semiconductive diode; a second
subcombination including said secondary winding, said capacitor,
and said diode operatively connected in series to charge said
capacitor by a current induced in said secondary winding by said
forementioned current flowing in the said primary winding; magnetic
field energy storage means operatively associated with said
transformer means and so arranged as to store energy and to release
energy during the time said forementioned current flows in said
primary winding and in cooperation with said transformer means
charging said capacitor, and said magnetic field energy storage
means limiting the maximum value of the said forementioned current
flowing in said primary winding; semiconductor switch means
including output circuit means and input circuit means to cause
said output circuit means to be conductive when current flows in
said input circuit means; means connected with said input circuit
means of said semiconductor switch means and being adapted to be
connected with said synchronizing means to cause current to flow in
synchronism with the operation of the engine, in said input circuit
means of said semiconductor switch means; and a third
subcombination including said output circuit means of said
semiconductor switch means and said capacitor operatively connected
in series, said third subcombination being adapted to be connected
with said ignition coil to discharge said capacitor through said
ignition coil to cause said spark discharge device to fire in
synchronism with the operation of the engine.
10. A capacitor charging and discharging system as claimed in claim
9 wherein said semiconductor means comprising transistor means and
said semiconductor switch means comprises silicon controlled
rectifier means.
11. A capacitor charging and discharging system as claimed in claim
10 wherein said magnetic field energy storage means comprises
inductance means included in said first subcombination.
12. A capacitor charging and discharging system as claimed in claim
10 wherein said magnetic field energy storage means comprises
inductance means included in said second subcombination.
13. A capacitor charging and discharging system as claimed in claim
9, and including means operatively associated with said transformer
means to prevent any magnetic field in said transformer means,
during the period said output circuit means of said semiconductor
means is non-conductive, from causing harm to said semiconductor
means.
14. A capacitor charging and discharging system as claimed in claim
13 wherein said semiconductor means comprises transistor means and
said semiconductor switch means comprises silicon controlled
rectifier means.
15. A capacitor charging and discharging system as claimed in claim
14 wherein said magnetic field energy storage means comprises
inductance means included in said first subcombination.
16. A capacitor charging and discharging system as claimed in claim
14 wherein said magnetic field energy storage means comprises
inductance means included in said second subcombination.
17. A capacitor charging and discharging system for use in an
ignition system adapted to ignite the combustible mixture of an
internal combustion engine, said ignition system including a source
of direct current, a spark discharge device, synchronizing means,
and an ignition coil operatively connected with said spark
discharge device, comprising in combination, a capacitor connected
to be charged and discharged; step-up transformer means including a
magnetic core, a primary winding, and a secondary winding, said
windings being disposed in relation to the said magnetic core and
in relation to each other so as to have substantially maximum
leakage inductances relative to the resistances of said windings,
whereby said leakage inductances store energy and release energy to
cooperate with the mutual magnetic flux in the said magnetic core
to charge said capacitor, and said leakage inductances limiting the
maximum value of the current that may flow in said primary winding
from said source of direct current; means connected with said
primary winding and said source of direct current to control the
flow of current in said primary winding from said source of direct
current, said last mentioned means permitting said current to flow
in synchronism with the operation of said engine and not permitting
said current to flow after said capacitor has been charged; a
semiconductor diode; a first subcombination including said
secondary winding, said diode, and said capacitor operatively
connected in series to charge said capacitor by a current induced
in said secondary winding by said forementioned current flowing in
said primary winding; semiconductor switch means including output
circuit means and input circuit means to cause said output circuit
means to be conductive when current flows in said input circuit
means; means connected with said input circuit means of said
semiconductor switch means and being adapted to be connected with
said synchronizing means to cause current to flow, in synchronism
with the operation of the engine, in said input circuit means of
said semiconductor switch means; and a second subcombination
including said output circuit means of said semiconductor switch
means and said capacitor operatively connected in series, said
second subcombination being adapted to be connected with said
ignition coil to discharge said capacitor through said ignition
coil to cause said spark discharge device to fire in synchronism
with the operation of the engine.
18. A capacitor charging and discharging system as claimed in claim
17 wherein said semiconductor switch means comprises silicon
controlled rectifier means.
19. A capacitor charging and discharging system as claimed in claim
18 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights, and in
which said primary winding and said secondary winding are disposed
side-by-side so as to cause said windings to have said
substantially maximum leakage inductances relative to the
resistances of said windings.
20. A capacitor charging and discharging system as claimed in claim
18 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights, and in
which said primary winding and said secondary winding are disposed
side-by-side and substantially filling said windows so as to cause
said windings to have said substantially maximum leakage
inductances relative to the resistances of the said windings.
21. A capacitor charging and discharging system as claimed in claim
17 and including means operatively associated with said transformer
means to prevent any magnetic field in said transformer means,
during the period said output circuit means of said semiconductor
means is nonconductive, from causing harm to said semiconductor
means.
22. A capacitor charging and discharging system as claimed in claim
21 wherein said semiconductor switch means comprises silicon
controlled rectifier means.
23. A capacitor charging and discharging system as claimed in claim
22 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights, and in
which said primary winding and said secondary winding are disposed
side-by-side so as to cause said windings to have said
substantially maximum leakage inductances relative to the
resistances of said windings.
24. A capacitor charging and discharging system as claimed in claim
22 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights, and in
which said primary winding and said secondary winding are disposed
side-by-side and substantially filling said windows so as to cause
said windings to have said substantially maximum leakage
inductances relative to the resistances of the said windings.
25. A capacitor charging and discharging system for use in an
ignition system adapted to ignite the combustible mixture of an
internal combustion engine, said ignition system including a source
of direct current, a spark discharge device, synchronizing means,
and an ignition coil operatively connected with said spark
discharge device, comprising in combination, step-up transformer
means including a magnetic core, a primary winding, and a secondary
winding; semiconductor means including output circuit means and
input circuit means to cause said output circuit means to be
conductive when current flows in said input circuit means; a first
subcombination including said output circuit means and said primary
winding operatively connected in series, said first subcombination
being adapted to be connected across said source of direct current
to permit, when said output circuit means is conductive, a current
to flow in said primary winding to energize said transformer means;
a capacitor; a semiconductor diode; a second subcombination
including said capacitor, said diode, said secondary winding, and
said input circuit means operatively connected in series, said
second subcombination being so arranged as to be connected with
said source of direct current when said first subcombination is
connected with said source of direct current to thereby cause,
after said capacitor is discharged, a current to flow in said input
circuit means which current causes said output circuit means to be
conductive which permits said transformer means to be energized and
thus causes said last mentioned current to continue to flow until
said capacitor is recharged; magnetic field energy storage means
operatively associated with said transformer means and so arranged
as to store energy and to release energy during the time said
forementioned current flows in said primary winding and in
cooperation with said transformer means charging said capacitor,
and said magnetic field energy storage means limiting the maximum
value of the said forementioned current flowing in said primary
winding; semiconductor switch means including output circuit means
and input circuit means to cause said output circuit means to be
conductive when current flows in said input circuit means; means
connected with said input circuit means of said semiconductor
switch means and being adapted to be connected with said
synchronizing means to cause current to flow, in synchronism with
the operation of the engine, in said input circuit means of said
semiconductor switch means; and a third subcombination including
said output circuit means of said semiconductor switch means and
said capacitor operatively connected in series, said third
subcombination being adapted to be connected with said ignition
coil to discharge said capacitor through said ignition coil to
cause said spark discharge device to fire in synchronism with the
operation of the engine.
26. A capacitor charging and discharging system as claimed in claim
25 wherein said semiconductor means comprises transistor means and
said semiconductor switch means comprises silicon controlled
rectifier means.
27. A capacitor charging and discharging system as claimed in claim
26 wherein said magnetic field energy storage means comprises
inductance means included in said second subcombination.
28. A capacitor charging and discharging system as claimed in claim
25, and including means operatively associated with said
transformer means to prevent any magnetic field in said transformer
means, during the period said output circuit means of said
semiconductor means is nonconductive, from causing harm to said
semiconductor means.
29. A capacitor charging and discharging system as claimed in claim
28 wherein said semiconductor means comprises transistor means and
said semiconductor switch means comprises silicon controlled
rectifier means.
30. A capacitor charging and discharging system as claimed in claim
29 wherein said magnetic field energy storage means comprises
inductance means included in said second subcombination.
31. A capacitor charging and discharging system for use in an
ignition system adapted to ignite the combustible mixture of an
internal combustion engine, said ignition system including a source
of direct current, a spark discharge device, synchronizing means,
and an ignition coil operatively connected with said spark
discharge device, comprising in combination, a capacitor connected
to be charged and discharged; step-up transformer means including a
magnetic core, a primary winding, and a secondary winding, said
windings being disposed in relation to the said magnetic core and
in relation to each other so as to have substantially maximum
leakage inductances relative to the resistances of said windings,
whereby said leakage inductances store energy and release energy to
cooperate with the mutual magnetic flux in the said magnetic core
to charge said capacitor, and said leakage inductances limiting the
maximum value of the current that may flow in said primary winding
from said source of direct current; semiconductor means including
output circuit means and input circuit means to control the
conductivity of said output circuit means; a first subcombination
including said output circuit means and said primary winding
operatively connected in series, said first subcombination being
adapted to be connected across said source of direct current to
permit, when said output circuit means is conductive, a current to
flow in said primary winding to energize said transformer means; a
semiconductor diode; a second subcombination including said
capacitor, said diode, said secondary winding, and said input
circuit means operatively connected in series, said second
subcombination being so arranged as to be connected with said
source of direct current when said first subcombination is
connected with said source of direct current to thereby cause,
after said capacitor is discharged, a current to flow in said input
circuit means which current causes aid output circuit means to be
conductive which permits said transformer means to be energized and
thus causes said last mentioned current to continue to flow until
said capacitor is recharged; semiconductor switch means including
output circuit means and input circuit means to cause said output
circuit means to be conductive when current flows in said input
circuit means; means connected with said input circuit means of
said semi-conductor switch means and being adapted to be connected
with said synchronizing means to cause current to flow, in
synchronism with the operation of the engine, in said input circuit
means of said semiconductor switch means; and a third
subcombination including said output circuit means of said
semiconductor switch means and said capacitor operatively connected
in series, said third subcombination being adapted to be connected
with said ignition coil to discharge said capacitor through said
ignition coil to cause said spark discharge device to fire in
synchronism with the operation of the engine.
32. A capacitor charging and discharging system as claimed in claim
31 wherein said semiconductor means comprises transistor means and
said semiconductor switch means comprises silicon controlled
rectifier means.
33. A capacitor charging and discharging system as claimed in claim
32 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights, and in
which said primary winding and said secondary winding are disposed
side-by-side so as to cause said windings to have said
substantially maximum leakage inductances relative to the
resistances of said windings.
34. A capacitor charging and discharging system as claimed in claim
32 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights, and in
which said primary winding and said secondary winding are disposed
side-by-side and substantially filling said windows so as to cause
said windings to have said substantially maximum leakage
inductances relative to the resistances of said windings.
35. A capacitor charging and discharging system as claimed in claim
31, and including means operatively associated with said
transformer means to prevent any magnetic field in said transformer
means, during the period said output circuit means of said
semiconductor means is nonconductive, from causing harm to said
semiconductor means.
36. A capacitor charging and discharging system as claimed in claim
35 wherein said semiconductor means comprises transistor means and
said semiconductor switch means comprises silicon controlled
rectifier means.
37. A capacitor charging and discharging system as claimed in claim
36 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights, and in
which said primary winding and said secondary winding are disposed
side-by-side so as to cause said windings to have said
substantially maximum leakage inductances relative to the
resistances of said windings.
38. A capacitor charging and discharging system as claimed in claim
36 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights, and in
which said primary winding and said secondary winding are disposed
side-by-side and substantially filling said windows so as to cause
said windings to have said substantially maximum leakage
inductances relative to the resistances of said windings.
39. A capacitor charging and discharging system for use in an
ignition system adapted to ignite the combustible mixture of an
internal combustion engine, said ignition system including a source
of direct current, a spark discharge device, synchronizing means,
and an ignition coil operatively connected with said spark
discharge device, comprising in combination, step-up transformer
means including a magnetic core, a primary winding, and a secondary
winding; semiconductor means including output circuit means and
input circuit means to cause said output circuit means to be
conductive when current flows in said input circuit means; a first
subcombination including said output circuit means and said primary
winding operatively connected in series, said first subcombination
being adapted to be connected across said source of direct current
to permit, when said output circuit means is conductive, a current
to flow in said primary winding to energize said transformer means;
a capacitor; a semiconductor diode; a second subcombination
including said capacitor, said semiconductor diode, said secondary
winding, and said input circuit means operatively connected in
series, said second subcombination being so arranged as to be
connected with said source of direct current when said first
subcombination is connected with said source of direct current to
thereby cause, if said capacitor happens to be uncharged when said
first subcombination is connected with said source of direct
current, a current to immediately flow in said input circuit means
which current causes said output circuit means to be conductive
which permits said transformer means to be energized and thus
causes said last mentioned current to continue to flow until said
capacitor is charged; semiconductor switch means including output
circuit means and input circuit means to cause said output circuit
means to be conductive when current flows in said input circuit
means; means connected with said input circuit means of said
semiconductor switch means and being adapted to be connected with
said synchronizing means to cause current to flow, in synchronism
with the operation of the engine, in said input circuit means of
said semiconductor switch means; and a third subcombination
including said output circuit means of said semiconductor switch
means and said capacitor operatively connected in series, said
third subcombination being adapted to be connected with said
ignition coil to discharge said capacitor through said ignition
coil to cause said spark discharge device to fire in synchronism
with the operation of the engine.
40. A capacitor charging and discharging system as claimed in claim
39 wherein said semiconductor means comprises transistor means and
said semiconductor switch means comprises silicon controlled
rectifier means.
41. A capacitor charging and discharging system as claimed in claim
39, and including means operatively associated with said
transformer means to prevent any magnetic field in said transformer
means, during the period said output circuit means of said
semiconductor means is nonconductive, from causing harm to said
semiconductor means.
42. A capacitor charging and discharging system as claimed in claim
41 wherein said semiconductor means comprises transistor means and
said semiconductor switch means comprises silicon controlled
rectifier means.
43. A capacitor charging and discharging system as claimed in claim
32 and including a second semiconductor diode operatively connected
across said input circuit means of said transistor means and in
which said third subcombination includes said second semiconductor
diode.
44. A capacitor charging and discharging system as claimed in claim
43 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights and in
which said primary winding and said secondary winding are disposed
side-by-side so as to cause said windings to have said
substantially maximum leakage inductances relative to the
resistances of said windings.
45. A capacitor charging and discharging system as claimed in claim
43 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights, and in
which said primary winding and said secondary winding are disposed
side-by-side and substantially filling said windows so as to cause
said windings to have said substantially maximum leakage
inductances relative to the resistances of said windings.
46. A capacitor charging and discharging system as claimed in claim
36 and including a second semiconductor diode operatively connected
across said input circuit means of said transistor means and in
which said third subcombination includes said second semiconductor
diode.
47. A capacitor charging and discharging system as claimed in claim
46 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights and in
which said primary winding and said secondary winding are disposed
side-by-side so as to cause said windings to have said
substantially maximum leakage inductances relative to the
resistances of said windings.
48. A capacitor charging and discharging system as claimed in claim
46 and in which said magnetic core includes two spaced parallel
windows, having axial lengths greater than their heights, and in
which said primary winding and said secondary winding are disposed
side-by-side and substantially filling said windows so as to cause
said windings to have said substantially maximum leakage
inductances relative to the resistances of said windings.
49. A capacitor charging and discharging system as claimed in claim
40 and including a second semiconductor diode operatively connected
across said input circuit means of said transistor means and in
which said third subcombination includes said second semiconductor
diode.
50. A capacitor charging and discharging system as claimed in claim
49 and in which said windings have substantially maximum leakage
inductances relative to the resistances of said windings whereby
said leakage inductances store energy and release energy to
cooperate with the mutual magnetic flux in tee said magnetic core
to charge said capacitor, and said leakage inductances limiting the
maximum value of the current that may flow in said primary winding
from said source of direct current.
51. A capacitor charging and discharging system as claimed in claim
49 and in which said first subcombination includes an inductance
operatively connected in series with said output circuit means of
said semiconductor means and said primary winding whereby said
inductance stores energy and releases energy to cooperate with said
transformer means to charge said capacitor, and said inductance
limiting the maximum value of current that may flow in said primary
winding from said source of direct current.
52. A capacitor charging and discharging system as claimed in claim
49 and in which said second subcombination includes an inductance
operatively connected in series with said capacitor, said first
semiconductor diode, said secondary winding, and said input circuit
means of said semiconductor means whereby said inductance stores
energy and releases energy to cooperate with said transformer means
to charge said capacitor, and said inductance limiting the maximum
value of current that may flow in said primary winding from said
source of direct current.
53. A capacitor charging and discharging system as claimed in claim
42 and including a second semiconductor diode operatively connected
across said input circuit means of said transistor means and in
which said third subcombination includes said second semiconductor
diode.
54. A capacitor charging and discharging system as claimed in claim
53 and in which said windings have substantially maximum leakage
inductances relative to the resistances of said windings whereby
said leakage inductances store energy and release energy to
cooperate with the mutual magnetic flux in the said magnetic core
to charge said capacitor, and said leakage inductances limiting the
maximum value of the current that may flow in said primary winding
from said source of direct current.
55. A capacitor charging and discharging system as claimed in claim
53 and in which said first subcombination includes an inductance
operatively connected in series with said output circuit means of
said semiconductor means and said primary winding whereby said
inductance stores energy and releases energy to cooperate with said
transformer means to charge said capacitor, and said inductance
limiting the maximum value of current that may flow in said primary
winding from said source of direct current.
56. A capacitor charging and discharging system as claimed in claim
53 and in which said second subcombination includes an inductance
operatively connected in series with said capacitor, said first
semiconductor diode, said secondary winding, and said input circuit
means of said semiconductor means whereby said inductance stores
energy and releases energy to cooperate with said transformer means
to charge said capacitor, and said inductance limiting the maximum
value of current that may flow in said primary winding from said
source of direct current.
57. A capacitor charging and discharging system as claimed in claim
36 and including a second semiconductor diode operatively connected
across said input circuit means of said transistor means and in
which said third subcombination includes said second semiconductor
diode, and further including an inductance and a third
semiconductor diode operatively connected in series, said
inductance and third semiconductor diode in series being
operatively connected across said capacitor to provide a partial
recharging of said capacitor.
Description
BACKGROUND OF THE INVENTION
This invention relates to ignition systems of the condenser
discharge type for igniting the combustible mixture in internal
combustion engines.
It is an object of this invention to provide an ignition system of
the condenser discharge type wherein energy is transferred from a
direct current source through a transformer into a condenser by a
unique and novel manner which results in a flexibility in the
design of practical ignition systems.
It is another object of this invention to provide an ignition
system for internal combustion engines whereby the energy drawn
from a direct current source or battery is substantially
proportioned to the rotative speed of the engine resulting in a
considerable saving of energy at the lower rotative speeds of the
engine. This is an especially good feature when the engine is being
started up for at this time the starter electric motor places a
heavy demand on the direct current source or battery.
Another object is to provide a circuit wherein energy consumed by
the transistor of the circuit during the time said transistor
switches from a conductive state to a non-conductive state is
considerably reduced, resulting in the transistor being operated at
cooler temperatures.
Another object is to provide a circuit wherein due to the position
of the transistor in the circuit the transistor is more difficult
to destroy by accidental physical shorts.
Another object is to provide an ignition coil or transformer of a
new design or principle embodying my invention for firing the spark
discharge device or spark plug of the engine.
Other objects and a fuller understanding of this invention may be
had by referring to the following description and claims, taken in
conjunction with the accompanying drawings, in which:
FIGS. 1,3,4,5,6,7,8,9,10 and 11 are complete schematic drawings,
and FIGS. 12 and 13 are partial schematic drawings, of ignition
systems made in accordance with my invention;
FIG. 2A illustrates graphically and generally how certain currents
vary with time. These certain currents are: the current charging
condenser or capacitor 26 in FIGS. 1, 4 and 6; the current flowing
in winding 22 of FIGS. 1 and 4 and in winding 40 of FIG. 6; and the
current flowing in winding 16 of FIGS. 1,3,4,5,6,7 and 8.
FIG. 2B illustrates graphically and substantially how certain
currents vary with time. These certain currents are the current
flowing in winding 22 and inductance 38 of FIGS. 3 and 5; and the
current flowing in winding 40 and inductance 38 of FIGS. 7 and
8.
CONSTRUCTION OF FIGS. 1,3,4,5,6,7,8,9,10,11,12 AND 13.
Reference numeral 11 refers to a source of direct current or, in
the drawings, a battery. Numeral 12 refers to the conventional
ignition switch of an internal combustion engine. Numeral 13 refers
generally to a P-N-P transistor having a collector electrode 13C, a
control or base electrode 13B, and an emitter electrode 13E. It
should be apparent to those skilled in the art that in some cases
an N-P-N transistor could be used for transistor 13. Numeral 14
generally designates a magnetic control device having three
windings on a common magnetic core, a primary winding 15 and two
secondary windings 16 and 17, respectively. Numeral 18 is a current
limiting resistor. Numerals 19A and 19B refer to the standard
breaker contacts. Numeral 20 is a cam rotated by the engine which
causes breaker contacts 19A and 19B to be opened and closed in
synchronism with the operation of the engine in a manner well known
to those skilled in the art.
Numeral 21 in FIGS. 1, 3, 4 and 5 generally designates a
transformer having a primary or low voltage winding 22 and a
secondary or high voltage winding 23. Numerals 24 and 25 are
semi-conductor diodes but could be any device that passes current
substantially in one direction. Numeral 26 is a storage condenser
to be charged and discharged in synchronism with the operation of
the engine. As used in this patent application, the terms
"condenser" and "capacitor" are interchangeable as being
synonymous. Numeral 27 is a resistor used to dissipate energy in
the form of heat. Numeral 28 generally designates a silicon
controlled rectifier having a cathode electrode 28C, an anode
electrode 28A, and a control or gate electrode 28G. However, it is
to be understood that a thyratron tube or other appropriate
electronic switch device could be used for silicon controlled
rectifier 28 without departing from the spirit and scope of my
invention.
Numeral 29 in FIGS. 1, 3, 4 and 5 generally designates a standard
type ignition coil having a primary of low voltage winding 30 and a
secondary or high voltage winding 31. Numeral 32 designates
schematically a rotor contact which is caused to be rotated by the
engine and in synchronism with the operation of the engine and
therefore in synchronism with the operation of breaker contacts 19A
and 19B. Rotor contact 32 cooperates with a plurality of contacts
33, in the drawings four are shown, located on a conventional
distributor cap 34. For convenience of illustration, one of the
four contacts 33 is shown connected to one side of a spark plug 35.
The opposite side of spark plug 35 is connected to ground. It will
be appreciated that in an actual ignition system each one of the
contacts 33 is connected with a respective spark plug or spark
discharge device.
The breaker points 19A and 19B illustrated in FIGS.
1,3,4,5,6,7,8,9,10 and 11 are for the purpose of illustrating, by
way of example, synchronizing means associated with the various
embodiments of my invention. The function of breaker points 19A and
19B illustrated in said embodiments of my invention is to
synchronize the operation of said various embodiments of ignitions
stems with the operation of the engine. Other synchronizing means
that are actuated in synchronism with the operation of the engine,
and which are adapted by the proper circuitry to said various
embodiments, can be used instead of breaker points 19A and 19B. For
example, the breakerless distributor described in U.S. Pat. No.
3,254,247 could be used instead of a distributor having the breaker
points 19A and 19B.
In FIGS. 4, 5, 6 and 8, numeral 36 refers to a condenser. Numerals
37 and 38 refer to inductance. Numeral 39 in FIGS. 6, 7 and 8
generally refers to an ignition coil or transformer of a new design
or principle embodying my invention and will be more fully
described in the description of operation of FIGS. 6, 7 and 8.
FEATURES COMMON TO THE OPERATION OF FIGS. 1, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12 AND 13
The following descriptions of operation of the various circuits
embodying my invention will consist of describing the operation for
one closing and one opening of contacts 19A and 19B, although it is
to be understood that the same cycle is continually taking place as
long as the engine shaft is being rotated. It is also to be
understood that the direction of current flow is taken to be in the
direction from a negative potential to a less negative potential.
As expressed herein and as understood by me, the direction of the
flow of electrons is the same as the direction of the flow of
current in a circuit. It is understood that there are different
theories on this matter, but I elect to describe the direction of
flow of current as being the same as the direction of the flow of
electrons. In any event, my system operates the same regardless of
which of these theories is chosen. It is also to be understood that
in all the figures, like numbered elements are the same elements
performing the same function in all the drawings, even though they
may be connected to different places in the circuits of the various
figures. Also, it is to be understood in all the descriptions of
the various figures that ignition switch 12 is considered to be
closed and that the engine is causing to be rotated the cam 20,
which i turn causes breaker contacts 19A and 19B to be opened and
closed, and that the engine is also causing to be rotated the rotor
contact 32 of distributor cap 34.
DESCRIPTION OF FIG. 1
Beginning at the instant of time when breaker contacts 19A and 19B
have just closed, a relatively small current will flow out of
battery 11, through contacts 19A and 19B, through resistor 18,
through winding 15, and then through switch 12 and back to the
battery 11. The magnetic sense of winding 16 is such that the
flowing of this current through winding 15 will cause an induced
current to flow out the bottom terminal of winding 16, into base
electrode 13B, out emitter electrode 13E, and back into the upper
terminal of winding 16. The variation of this current with time
will be substantially as illustrated graphically in FIG. 2A where
the vertical axis represents current or i and the horizontal axis
represents time or t.
The flowing of said current in the base to emitter path of
transistor 13 causes transistor 13 to be substantially conductive
between collector electrode 13C and emitter electrode 13E, thus
allowing a relatively larger current, also substantially of the
same shape in regard to time as illustrated in FIG. 2A, to flow
from the negative terminal of battery 11 into ground, from ground
through the collector electrode 13C to emitter electrode 13E path
of transistor 13, through winding 22, through switch 12 and then
back into the positive terminal of battery 11. The flow of this
current in winding 22 and the magnetic sense of winding 23 causes a
relatively smaller induced current to flow upward in winding 23 and
out its top terminal, through diode 24, into the upper terminal of
storage condenser 26, out the bottom of storage condenser 26 and
then back into the bottom terminal of winding 23. In other words,
the diode 24 is "poled" to permit the current to flow as described.
This last mentioned current flow in winding 23, although smaller,
is substantially proportional to the larger current flow in winding
22 and thus also varies with time substantially as illustrated in
FIG. 2A, and said current charges storage condenser 26 with
electrical energy making its top terminal negative.
The values of the components of magnetic control device 14 and
resistor 18 are chosen so that the current flowing in the base
electrode 13B to emitter electrode 13E path of transistor 13
decreases to zero value preferably at substantially the same time
or at a time approaching the time that the current charging storage
condenser 26 decreases to zero value, or to some other
predetermined value. The collector electrode 13C to emitter
electrode 13E of transistor 13 is thereby caused to become
substantially nonconductive at substantially the same time that the
current charging storage condenser 26 decreases to zero or to said
predetermined value and thus cuts off the current flowing in
winding 22 substantially at these same points in time. Thus the
amount of time that the current flows in winding 22 depends on the
values of the appropriate components of FIG. 1 and does not depend
on the amount of time that contacts 19A and 19B are closed which
time is inversely proportional to the rotative speed of the engine.
The action described in this paragraph results in less energy being
drawn from the battery at the lower rotative speeds of the engine
and is especially a good feature when the engine is being started
because at this time the starter motor places a heavy load upon the
battery.
The induced current flowing in winding 23 and which charges storage
condenser 26 is caused to flow by an induced voltage in winding 23
that is itself caused to be induced by the magnetic field being
built up by the flow of current in winding 22, and which said
induced voltage causes to be transferred the energy stored up in
storage condenser 26 directly from battery 11 energy. In other
words, the current flowing in winding 22 causes a magnetic field to
be built up in the core of transformer 21 and the building up of
this magnetic field induces a voltage in winding 23 which causes
the above described charging of condenser 26 with energy directly
from the battery 11. This is believed to be a unique way of
charging a condenser and is in contrast to other ignition systems
of the condenser discharge type which charge a condenser from a
direct current source of energy or a battery's energy but through
various intervening processes and not directly.
During the time that current is flowing in primary winding 22 a
magnetic field, possessing a relatively small amount of energy, is
built up in transformer 21 and when the current in primary winding
22 is cut off this magnetic field and its energy remains in
transformer 21. While this magnetic field and its energy cannot be
avoided, it is incidental to the operation of my invention and said
magnetic field and its energy must be substantially disposed of in
order to keep from harming transistor 13 and in order that the
magnetic field of transformer 21 be as small as possible when
transistor 13 becomes conductive again. Diode 25 and resistor 27
are connected across winding 23 for the purpose of dissipating the
energy of the last mentioned magnetic field. When the collector
electrode 13C to emitter electrode 13E path of transistor 13
becomes substantially non-conductive, a relatively small current
will flow downward in winding 23 out its bottom terminal, through
resistor 27, through diode 25, and then back into the top terminal
of winding 23. The flowing of this current will dissipate the
energy of the magnetic field, mentioned in this paragraph, in the
resistance of the last mentioned circuit.
Beginning at the time when breaker contacts 19A and 19B open, the
current flowing in winding 15 is cut off and this induces a voltage
in winding 17. The magnetic sense of winding 17 is such that this
last mentioned induced voltage causes a current to flow out of the
upper terminal of winding 17 into cathode electrode 28C, out gate
electrode 28G, and then back into the bottom terminal of winding
17. This flow of current in the control circuit of silicon
controlled rectifier 28 causes said silicon controlled rectifier to
be conductive between its cathode electrode 28C and its anode
electrode 28A and a large current will flow out of the negative
upper terminal of storage condenser 26 into cathode electrode 28C,
out of anode electrode 28A through winding 30 into ground, and out
of ground into the lower plate of storage condenser 26. The flow of
this current substantially discharges storage condenser 26. As a
result of this last mentioned current flow in winding 30, a large
voltage is induced in secondary winding 31, which is applied to a
spark plug 35 by way or rotor contact 32 and one of the contacts 33
carried by distributor cap 34 which fires spark plug 35.
In the above description of operation of FIG. 1, I have described
the circuit for one cycle of operation; that is, for one closing
and one opening of contacts 19A and 19B although it is to be
understood that the same cycle is repeated over and over.
DESCRIPTION OF FIG. 3
FIG. 3 is a modification of the circuit of FIG. 1. In accordance
with this modification, an inductance 38 is connected between the
lower terminal of winding 22 and emitter electrode 13E and also the
series combination of diode 25 and resistor 27 is connected across
the series combination of inductance 38 and winding 22 as shown in
FIG. 3.
Beginning at the time when contacts 19A and 19B have just closed,
transistor 13 will become conductive between collector electrode
13C and emitter electrode 13E as in the circuit of FIG. 1 and a
current will flow out of the negative terminal of battery 11 into
ground, from ground into collector electrode 13C, out emitter
electrode 13E, through inductance 38, through winding 22, and then
through switch 12 and back to the upper positive terminal of
battery 11. This current in inductance 38 and winding 22
substantially varies with time as illustrated in FIG. 2B, starting
from a zero value and increasing to a maximum value and decreasing
to a minimum value.
Transformer 14 is so designed that along with the proper value of
resistor 18, the current flowing in the base electrode 13B to
emitter electrode 13E path of transistor 13 decreases to zero
substantially at the same time that the current in inductance 38
and winding 22 decreases to a minimum value and causes transistor
13 to become non-conductive between its collector electrode 13C and
emitter electrode 13E, cutting off the current in inductance 38 and
winding 22. During the flow of current in inductance 38 and winding
22, the storage condenser 26 is charged in a manner similar to that
described for the operation of FIG. 1 with the following
exception.
In the circuit of FIG. 3, energy is transferred from battery 11
into storage condenser 26 by the combination of two processes. One,
energy is transferred directly from battery 11 through transformer
21 into condenser 26 as in the circuit of FIG. 1, and two, energy
from battery 11 is first momentarily stored in inductance 38 and
then inductance 38 releases this energy which is transferred into
condenser 26 by transformer 21.
At the time when the current in inductance 38 and winding 22 is cut
off, there will be a magnetic field in each of these elements
possessing relatively small amounts of energy and a current will
flow upward in inductance 38, through winding 22, through diode 25,
through resistor 27 and back into the lower terminal of inductance
38 and said flow of current through the resistance of said circuit
will dissipate both the said magnetic energies in the form of heat.
In short, the magnetic energies in inductance 38 and in winding 22
are dissipated in the form of heat.
The parts of the circuit of FIG. 3 not described here operate and
function in the same manner as described for FIG. 1. The presence
of inductance 38 in the circuit of FIG. 3 increases the voltage
with which condenser 26 is charged, with a given turn ratio of
windings of transformer 21.
Inductance 38 limits the maximum value of the current flowing in
primary winding 22 when the output circuit of transistor 13 is
conductive. Since the current flowing in secondary winding 23 is
substantially proportional to the current flowing in primary
winding 22 during this same time, inductance 38 also limits the
maximum value of the secondary current which also varies
substantially as illustrated by FIG. 2B. Thus, it is not necessary
to limit the maximum value of these same two currents by electrical
resistance but it is in fact desirable to keep the value of the
electrical resistance of the circuits, in which these same two
currents flow, as small as possible. The smaller the losses in the
magnetic core of transformer 21 and the smaller the electrical
resistances, just mentioned, the greater the voltage to which the
storage capacitor 26 is charged.
DESCRIPTION OF FIG. 4
FIG. 4 is a modification of FIG. 1 and in accordance with this
modification a condenser 36 and an inductance 37 as connected in
series across the series combination of condenser 26 and silicon
controlled rectifier 28. Low voltage winding 30 is connected across
condenser 36.
The manner in which this modification operates is as follows: With
condenser 26 charged and beginning at a time when contacts 19A and
19B have just opened, and thus silicon controlled rectifier 28 has
just become conductive between its cathode electrode 28C and its
anode electrode 28A, a relatively large current will flow out of
the negative upper terminal of condenser 26, through the cathode
electrode 28C to anode electrode 28A path of silicon controlled
rectifier 28, through inductance 27, into the upper terminal of
condenser 36 making it negative, out the lower terminal of
condenser 26 into ground, from ground back into the lower terminal
of condenser 26.
As a result of this current flow, condenser 26 is substantially
discharged and condenser 36 is charged, and a voltage will rise
rapidly across condenser 36 with the proper value of inductance 37.
Since winding 30 is across or in parallel with condenser 36, the
same voltage will rise rapidly across winding 30 and this in turn
causes a proportionally much larger induced voltage to rise rapidly
across winding 31. The voltage across winding 31 is applied to a
spark plug 35 by way of rotor contact 32 and one of the contacts 33
carried by distributor cap 34. When the voltage across winding 31
rises to a certain value, the spark plug 35 fires and condenser 36
is discharged.
The presence of inductance 37 in the circuit of FIG. 4 limits the
size of the discharge current of condenser 26 and prevents silicon
controlled rectifier 28 from being destroyed by any physical shorts
in transformer 29 or by any grounds in the secondary circuit of
transformer 29.
DESCRIPTION OF FIG. 5
The circuit of FIg. 5 is modified from the circuit of FIG. 1 by the
inclusion of inductance 37 and condenser 36 and these elements
affect the circuit of FIG. 5 in the same manner that they affected
the circuit of FIG. 4. The circuit of FIg. 5 is also modified from
the circuit of FIG. 1 by the inclusion of energy inductance 38 and
the series connected combination of diode 25 and energy dissipating
resistor 27 as shown in FIG. 5 and these elements affect the
circuit of FIG. 5 in the same manner as they affected the circuit
of FIG. 3.
DESCRIPTION OF FIG. 6
The circuit of FIG. 6 is particularly modified from the circuit of
FIG. 1 in the following respect. In FIG. 6 a unique and novel
ignition coil or transformer embodying a feature of a form of my
invention and generally designated by reference numeral 39 takes
the place of an performs the functions of both the transformer 21
and the standard ignition coil 29 of FIG. 1.
Transformer 39 consists of two main windings on a common magnetic
core, a primary winding 40 and a secondary winding that is tapped
at two points to form three different functional secondary windings
41, 42 and 43.
It is to be understood that as connected in FIG. 6, all four
windings 40, 41, 42 and 43 have the same magnetic sense, that is,
if an induced voltage in one winding, caused by a change in the
magnetic field of transformer 39, tends to cause a current to flow
in that winding in a certain direction, either in an upward or
downward direction when viewing FIG. 6, then there will be induced
voltages in the remaining three windings tending to cause a current
to flow in each in the same direction.
In the circuit of FIG. 6, winding 40 performs the same function
that winding 22 does in FIG. 1; winding 41 of FIG. 6 performs the
same function that winding 23 performs in FIG. 1; and the additive
combination of windings 41 and 43 of FIG. 4 performs the same
function that winding 31 performs in FIG. 1. Also winding 42 of
FIG. 6 performs the same function that winding 30 performs in FIG.
1 plus an additional function of disposing of the energy of the
magnetic field of transformer 39, as will be explained below.
Beginning at an instant when contacts 19A and 19B have just closed,
transistor 13 will be caused to become conductive by magnetic
control device 14 in the same manner as was described for FIG. 1. A
current from battery 11 will then flow in winding 40 in the same
manner that a current flowed in winding 22 of FIG. 1.
The flowing of said current in winding 40 will cause an induced
current to flow in winding 41 for the same reason and in a similar
manner as was described for the current flow in winding 23 of FIG.
1. The induced current in winding 41 will flow downward and out its
lower terminal into ground, from ground into the lower terminal of
condenser 26, out the upper terminal of condenser 26, and through
diode 24 and back into the upper terminal of winding 41. The flow
of this current results in condenser 26 being charged and the lower
terminal of condenser 26 to become negative.
When transistor 13 becomes substantially non-conductive, in the
same manner as was described for FIG. 1, there will be a magnetic
field in transformer 39 just as there was in transformer 21 of FIG.
1, and the energy of this magnetic field must be disposed of as was
done in connection with FIG. 1. Thus when transistor 13 becomes
substantially non-conductive, an induced current will flow upward
in the winding 42 and out the upper terminal of winding 42 into
ground, from ground into the lower terminal of condenser 36, out
the upper terminal of condenser 36 and back into the lower terminal
of winding 42. The flow of this current will dispose of the energy
of the magnetic field of transformer 39 by storing some energy in
condenser 36 and which will make the lower terminal of condenser 36
negative. The energy stored in condenser 36 is minor and the main
purpose of this last mentioned action being to dispose of the
energy of the magnetic field of transformer 39 that exists in
transformer 39 at the time that transistor 13 becomes substantially
nonconductive.
When contacts 19A and 19B open, silicon controlled rectifier 28
becomes conductive in the same manner that it did in FIG. 1 and a
large limited current flows out of the negative lower terminal of
condenser 26 into ground, from ground into the lower terminal of
condenser 36, out of the upper terminal of condenser 36 and through
inductance 37, then into cathode electrode 28C of silicon
controlled rectifier 28, then out of anode electrode 28A and back
into the upper terminal of condenser 26. The flow of this current
charges condenser 36, making its lower terminal negative, and the
voltage on condenser 36 will rise very rapidly with the proper
value of inductance 37. Since winding 42 is connected across
condenser 36, there will be the same voltage rise on winding 42 and
this will cause a proportionally greater induced voltage rise
across the series combination of windings 41 and 42. The direction
of this latter induced voltage rise will be upward in both windings
41 and 43 and will be applied across the spark gap of spark plug 35
by way of rotor contact 32 and one of the contacts 33 carried by
distributor cap 34. When the voltage rise on the series combination
of windings 41 and 43 reaches a certain value, the spark plug 35
fires and condenser 36 is discharged.
DESCRIPTION OF FIG. 7
The circuit of FIG. 7 is a modification of FIG. 6. In FIG. 7
inductance 37 and condenser 36 have been excluded. In FIG. 7 when
silicon controlled rectifier 28 becomes conductive, the voltage on
condenser 26 is applied across winding 42 and this causes
transformer 39 to fire spark plug 35 in the same manner that the
voltage of condenser 36 of FIG. 6 across winding 42 caused spark
plug 35 to fire in the circuit of FIG. 6.
FIG. 7 is also modified from FIG. 6 by the inclusion of diode 25
and resistor 27 and these two elements have the same effect in the
circuit that they had in the circuit of FIG. 3, as will be readily
apparent to those skilled in the art.
FIG. 7 is also modified from the circuit of FIG. 6 by the inclusion
of inductance 38 which is connected between the lower terminal of
winding 40 and emitter electrode 13E. Inductance 38 has the same
effect on the circuit of FIG. 7 that it had on the circuit of FIG.
3. Inductance 38 also has an effect on the circuit of FIG. 7 that
it does not have in the circuit of FIG 3, specifically the
following effect. When silicon controlled rectifier 28 becomes
conductive in the circuit of FIG. 7, the voltage of condenser 26 is
applied across winding 42 which causes an induced voltage in
winding 40 and inductance 38 effectively prevents this induced
voltage in winding 40 from being applied across the collector
electrode 13C to emitter electrode 13E of transistor 13 and
prevents transistor 13 from being destroyed if this induced voltage
in winding 40 is too large a value for transistor 13.
DESCRIPTION OF FIG. 8
FIG. 8 is modified from the circuit of FIG. 6 by the inclusion of
diode 25, resistor 27 and inductance 38. These elements are
connected as shown in FIG. 8 and they have the same effect on the
circuit of FIG. 8 that they have on the circuit of FIG. 7.
DESCRIPTION OF FIG. 9
The circuit of FIG. 9 is modified from the circuit of FIG. 3 and
differs in the following respects: Numeral 47 designates a
capacitor which is connected between collector electrode 13C and
emitter electrode 13E. Numeral 48 generally designates a magnetic
control device having a primary winding and a secondary winding
wound on a common magnetic core. Numeral 49 designates said primary
winding and numeral 50 designates said secondary winding. Numeral
51 designates a semi-conductor diode which is connected across
primary winding 49. Inductance 52 is connected with one end of
secondary winding 23. The other end of secondary winding 23 is
connected to base electrode 13B. Other differences between FIG. 9
and FIG. 3 may be noted by referring to the drawings and the
following description.
Assuming for the present that ignition switch 12 is closed, that
current is flowing in primary winding 49, that a magnetic field
exists in the core of magnetic control device 48, and that storage
capacitor 26 has a negative charge on its lower plate or terminal
which is connected to ground, the operation of FIG. 9 is as
follows:
Beginning at a time when breaker contacts 19A and 19B just open,
the current flowing in primary winding 49 is cut off and causes the
magnetic field in the magnetic core of magnetic control device to
collapse and induce a voltage in secondary winding 50. The magnetic
sense of secondary winding 50 is such that the induced voltage
causes a current to flow in the input circuit of silicon controlled
rectifier 28 which causes the output circuit of silicon controlled
rectifier 28 to be conductive. When the output circuit of silicon
controlled rectifier 28 thus becomes conductive, a relatively large
current flows out of the negative lower or grounded plate or
terminal of storage capacitor 26, through low voltage winding 30,
through the output circuit of silicon controlled rectifier 28, and
back into the upper or non-grounded plate or terminal of storage
capacitor 26. As a result of this current flow in low voltage
winding 30 a relatively large voltage is induced in high voltage
winding 31 which is applied to spark plug 35 by way of rotor 32 and
one of the contacts 33 carried by distributor cap 34 which fires
spark plug 35. All the energy of storage capacitor 26 is not used
during the flow of this last mentioned current and when this
current has ceased, storage capacitor 26 will be left with a
reverse or negative charge on its upper or non-grounded plate or
terminal. The presence of this negative charge on the upper or
non-grounded plate or terminal of storage capacitor 26 will cause
the output circuit of silicon controlled rectifier 28 to become
non-conductive and the output circuit will remain non-conductive
until the next opening of breaker contacts 19A and 19B.
After the firing of spark plug 35 the negative charge or voltage on
capacitor 26 and the voltage of battery 11 will aid each other to
cause a relatively small current to flow, out of the negative upper
plate or terminal of storage capacitor 26, through semi-conductor
diode 24, through inductance 52, through secondary winding 23,
through the input circuit of transistor 13, through ignition switch
12, through battery 11, and back into the lower plate or terminal
of storage capacitor 26. For purpose of explanation this circuit,
just described, I will refer to as "the charging circuit". This
small current flowing in the input circuit of transistor 13 causes
the output circuit of transistor 13 to be conductive and then
battery 11 causes a relatively larger current to flow out of its
negative terminal, through primary winding 22, through the
conductive output circuit of transistor 13, through ignition switch
12, and back into its positive terminal. The flow of this current
in primary winding 22 will energize transformer 21 and cause a
voltage to be induced in secondary winding 23. The magnetic sense
of secondary winding 23 is such that the voltage induced in it
causes the upper end of secondary winding 23 to be negative in
respect to its lower end. The induced voltage in secondary winding
23, thus having the proper polarity, causes the current flowing in
the charging circuit to continue to flow until storage capacitor 26
is fully charged, with its lower plate or terminal then being
negative. During the time this current is flowing in the charging
circuit to charge storage capacitor 26 it maintains the output
circuit of transistor 13 conductive because it flows through the
input circuit of transistor 13. Since the output circuit of
transistor 13 is conductive during the charging of storage
capacitor 26 current flows in primary winding 22 during this same
period of time and energizes transformer 21 which energizes the
charging circuit to charge the capacitor 26.
The small current flowing in the charging circuit which includes
inductance 52 and the larger current flowing in primary winding 22
are pulses of current, both currents varying with respect to time,
substantially as illustrated by FIG. 2B.
When the pulse of current flowing in inductance 52 is increasing to
a maximum value, energy is being stored in the magnetic field of
inductance 52 and when this current is decreasing to a minimum
value, the magnetic field of inductance 52 releases its energy into
storage capacitor 26. Inductance 52 limits the maximum value of the
currents flowing in the circuits and components involved in the
charging of storage capacitor 26. It is desirable to make the
electrical resistances, of the circuits and components which are
involved in charging storage capacitor 26, as small as possible.
Inductance 52 causes storage capacitor 26 to be charged to a
voltage greater than possible by transformer 21 acting along. The
smaller the losses in the magnetic core of transformer 21 and the
smaller the electrical resistances of the circuits and components
which are involved in charging storage capacitor 26, the greater
the voltage with which the storage capacitor 26 will be
charged.
During the period of time the output circuit of transistor 13 is
conductive and current is flowing in primary winding 22, a magnetic
field is built up in the magnetic core of transformer 21. When the
output circuit of transistor 13 becomes non-conductive and cuts off
the current in primary winding 22, the magnetic field existing in
transformer 21 collapses and causes an induced current to flow out
of the upper end of primary winding 22, into and out of capacitor
47, through ignition switch 12, through battery 11, and back into
the lower end of primary winding 22. This induced current flows
back and forth in this last mentioned circuit until the energy that
existed in the magnetic field of transformer 21 has been dissipated
in the form of heat partly by reason of the electrical resistance
of the circuit in which the induced current flows, and partly by
reason of the hysteresis loss in the magnetic core of transformer
21.
When breaker contacts 19A and 19B close, a current flows out of the
negative terminal of battery 11, through closed breaker contacts
19A and 19B, through resistor 18, through primary winding 49,
through ignition switch 12, and back into the upper positive
terminal of battery 11. The flowing of this current in primary
winding 49 builds a magnetic field up in the magnetic core of
magnetic control device 48. The function of resistor 18 is to limit
the value of current flowing in primary winding 49 to a desired
value. The function of semi-conductor diode 51 is to limit the
negative induced voltage on gate electrode 28G when breaker
contacts 19A and 19B close. The circuit of FIG. 9 is then in
condition for the next opening of breaker contacts 19A and 19B. The
sequence of the above described operation is consecutively repeated
for each following opening and closing of contacts 19A and 19B.
It may be noted that if storage capacitor 26 happens to be
uncharged when the ignition switch 12 is closed then battery 11
will cause a current to flow in the charging circuit and this will
trigger the output circuit of transistor 13 into a conductive state
or condition. When the said output circuit of transistor 13 is thus
in a conductive state or condition, the capacitor 26 is charged in
the manner previously described.
DESCRIPTION OF FIG. 10
The circuit of FIG. 10 is a modification of FIGS. 3 and 9 and
differs from FIGS. 3 and 9 in the following respects. Numeral 44
designates a semi-conductor diode. Numeral 45 designates a
capacitor. Numeral 46 designates a semi-conductor diode. Numeral 45
designates a capacitor. Numeral 46 designates a resistor. In the
drawing of FIG. 10, a pictorial top plan view of a specially built
transformer, designated generally by the numeral 21A, is shown for
the purpose of better explanation of this modification. Other
differences may be noted by referring to the drawings.
As shown in FIG. 10, the magnetic core of transformer 21A is the
shell type core, the axial length of the windows is about three
times greater than the heights of the windows. Numeral 22A
designates the primary or low voltage winding. Numeral 23A
designates the secondary or high voltage winding. The two windings,
primary winding 22A and secondary winding 23A, are wound
concentrically about the center leg of the magnetic core. The two
windings are disposed side-by-side on the center leg of the
magnetic core, as shown in the drawing. The two windings preferably
occupy equal areas of each window area so that the heat losses of
the two windings may be as nearly equalized as possible. Together
the two windings preferably occupy as much of the areas of the
windows as practically possible so that each winding has as small a
resistance as practically possible. The ratio of resistance to
leakage inductance is here considered to be the numerical value
that equals the numerical value of the resistance in ohms divided
by the numerical value of the leakage inductance in henries. When
wound in the manner described above and disposed on the center leg
side-by-side, each of primary winding 22A and secondary winding 23A
has a considerably smaller ratio of resistance to leakage
inductance than when one of the primary and secondary windings is
wound superimposed over the other winding of said windings as is
customary in a two-winding small conventional power transformer.
Transformer 21A is wound to provide a low ratio of resistance to
leakage inductance for the purpose of the circuit of FIG. 10.
In my special transformer, the leakage inductance of a winding
relative to the resistance of the same winding is several times
greater, on the order of about ten times greater for example, than
is the leakage inductance of a similar winding relative to the same
amount of resistance in the corresponding winding of comparable
conventional transformers. This is obtained by the construction and
arrangement of the core and the windings in the windows of the core
as above described.
In the ratio of R/L, wherein "R" is the resistance in a winding and
"L" is the inductance in the same winding, my special transformer
as above described has a relatively large, say on the order of ten
times as much, leakage inductance, assuming the same amount of
resistance in the corresponding winding of a comparable
conventional transformer.
The ratio of R/L influences the degree of the voltage with which
capacitor 26 is charged. The smaller the ratio, that is the larger
the leakage inductance is to the resistance of the same winding,
the greater the voltage with which the capacitor is charged.
More detailed information on how to obtain leakage inductance,
sufficient for the purposes of FIG. 10, may be had by referring to
the first edition of a book entitled "Small Transformers and
Inductors" by K.A. MacFayden and published in 1953 by Chapman and
Hall, 37 Essex Street, W.C. 2, London, Eng.
Assuming that ignition switch 12 is closed, that the engine is
running and causing breaker contacts 19A and 19B to be repeatedly
opened and closed, and that storage capacitor 26 has a negative
charge on its right hand plate or terminal, the operation of FIG.
10 is as follows.
Beginning at a time when breaker contacts 19A and 19B have just
opened, a small current will flow, out of the negative terminal of
battery 11 into ground, from ground through the input circuit of
silicon controlled rectifier 28, through semi-conductor diode 44,
into and out of capacitor 45, through resistor 18, through ignition
switch 12, and back into the positive terminal of battery 11. This
small current flowing in the input circuit of silicon controlled
rectifier 28 causes the output circuit of silicon controlled
rectifier 28 to become conductive. When the output circuit of
silicon controlled rectifier 28 thus becomes conductive, a
relatively large current flows out of the negative right hand plate
or terminal of storage capacitor 26, through low voltage winding
30, through the output circuit of silicon controlled rectifier 28,
and back into the left hand plate or terminal of storage capacitor
26. As a result of this current flow in low voltage winding 30, a
relatively large voltage is induced in high voltage winding 31
which is applied to spark plug 35 by way of rotor 32 and one of the
contacts carried by distributor cap 34 which fires spark plug 35.
All of the energy of storage capacitor 26 is not used during the
flow of this last mentioned current and when it has ceased flowing,
storage capacitor 26 will be left with a reverse or negative charge
on its left hand plate or terminal. The presence of this negative
charge or voltage on the left hand plate or terminal of storage
capacitor 26 causes the output circuit of silicon controlled
rectifier 28 to become nonconductive and the output circuit of
silicon controlled rectifier 28 remains nonconductive until the
next opening of breaker contacts 19A and 19B.
After the firing of spark plug 35 the negative voltage on the left
hand plate or terminal of storage capacitor 26 and the voltage of
battery 11 will aid each other to cause a relatively small current
to flow out of the negative left hand plate or terminal of storage
capacitor 26, through semiconductor diode 24, through secondary
winding 23A, through the input circuit of transistor 13, through
primary winding 22A, through ignition switch 12, into battery 11,
out of battery 11 and into ground, from ground through low voltage
winding 30, and back into the right hand plate or terminal of
storage capacitor 26. For purposes of explanation, I will refer to
this circuit, just described, as "the charging circuit". The small
current flowing in the input circuit of transistor 13 causes the
output circuit of transistor 13 to be conductive. When the output
circuit of transistor 13 thus becomes conductive, battery 11 causes
a relatively larger current to flow out of its negative terminal,
through the conductive output circuit of transistor 13, through
primary winding 22A, through ignition switch 12, and back into the
positive terminal of battery 11. The flow of this current in
primary winding 22A energizes transformer 21A and causes a voltage
to be induced in secondary winding 23A. The magnetic sense of
secondary winding 23A is such that, the voltage induced in it
causes the lower end of secondary winding 23A to be negative in
respect to its upper end. The induced voltage in secondary winding
23A, thus having the proper polarity, causes the current flowing in
the charging circuit to continue to flow until storage capacitor 26
is fully charged, with its right hand plate then being negatively
charged. During the time this current is flowing in the charging
circuit to charge storage capacitor 26, the output circuit of
transistor 13 is maintained conductive because the current flowing
in the charging circuit flows in the input circuit of transistor
13. Since the output circuit of transistor 13 is conductive during
the charging of storage capacitor 26, current flows in primary
winding 22A during this same period of time and energizes
transformer 21A which energizes the charging circuit to charge the
storage capacitor 26.
The small current flowing in the charging circuit which includes
secondary winding 23A and the larger current flowing in primary
winding 22A, during the period of time the output circuit of
transistor 13 is conductive, are pulses of current. Both pulses of
currents vary with respect to time substantially as illustrated by
FIG. 2B.
Leakage inductance associated with a winding of a two-winding
transformer is considered, for purposes of analysis, as being
caused by a leakage magnetic field that exists when current flows
in the winding and this leakage magnetic field is further
considered as linking only that winding producing it and not the
other winding of the transformer.
During the period of time, substantially illustrated by FIG. 2B,
that the currents flowing in primary winding 22A and secondary
winding 23A are increasing toward a maximum value energy is being
stored in the leakage magnetic fields associated with these
windings. During the period of time that said currents are
decreasing to a minimum value, said leakage magnetic fields are
releasing said stored energy and said released energy is being
caused to be transferred into storage capacitor 26.
The leakage inductances designed and built into transformer 21A
limits the maximum value of the current flowing in primary winding
22A and hence limits the current flowing in the output circuit of
transistor 13 and also limits the maximum value of the current
flowing in the charging circuit. It is desirable to make the
electrical resistance, of the two circuits and components involved
in charging storage capacitor 26, as small as possible. Storage
capacitor 26 is charged with a voltage substantially greater than
the voltage of battery 11 as multiplied by the turn ratio of the
transformer 21A by reason of the inclusion of the described leakage
inductances in the transformer 21A. The smaller the losses in the
magnetic core of transformer 21A and the smaller the electrical
resistances of the two circuits and components which are involved
in charging storage capacitor 26, the greater the voltage with
which the storage capacitor 26 will be charged.
It is well known that the input and output circuits of a transistor
can conduct but a limited amount of current, and that subjecting
either of these circuits to too much current can burn out, destroy
and render inoperative said circuits. I protect the transistor 13
of my circuits against such destruction by reason of an over-supply
of current by limiting the current supplied thereto by inductance,
which in FIG. 3 is the inductance 38, in FIG. 9 is inductance 52,
and, in FIG. 10 is the leakage inductance designed and built into
the transformer 21A.
During the period of time the output circuit of transistor 13 is
conductive, a magnetic field is built up in the magnetic core of
transformer 21A. When the output circuit of transistor 13 becomes
nonconductive, an induced current flows out of the upper end of
primary winding 22A, through ignition switch 12, through battery
11, into and out of capacitor 47, and back into the lower end of
primary winding 22A. This induced current flows back and forth in
the last mentioned circuit until the energy that existed in the
magnetic field of transformer 21A has been dissipated in the form
of heat, partly by reason of the electrical resistance of the
circuit and partly by reason of the hysteresis loss in the magnetic
core of transformer 21A. The said dissipation of the said energy
prevents harm to transistor 13 and reduces the magnetic field in
the core of transformer 21A.
During the time breaker contacts 19A and 19B are open, the current
that flows in the input circuit of silicon control rectifier,
previously described, charges the upper plate of capacitor 45 with
a negative charge or voltage. When contacts 19A and 19B close,
capacitor 45 discharges through resistor 46. Semi-conductor diode
44 prevents the negative voltage on capacitor 45 from being applied
to gate electrode 28G while capacitor 45 is being discharged. The
value of resistance of resistor 46 is made great enough so that it
has negligible influence on the input circuit of silicon controlled
rectifier when breaker contacts 19A and 19B are open. Resistor 18
limits the current flowing in the input circuit of silicon
controlled rectifier 28 when breaker contacts 19A and 19B are open,
and limits the current flowing through breaker contacts 19A and 19B
when they are closed.
It may be noted that if storage capacitor 26 happens to be
uncharged when the ignition switch 12 is closed, then battery 11
will cause a current to flow in the charging circuit and this will
trigger the output circuit of transistor 13 into a conductive state
or condition. When the said output circuit of transistor 13 is thus
in a conductive state or condition, the storage capacitor 26 is
charged in the manner previously described.
In the description and claims, in referring to my transistor and my
silicon controlled rectifier, I have used the terms "input circuit"
and "output circuit". In my transistor 13, for example, the "input
circuit" is the path for the current to flow in the transistor
between base 13B and emitter 13E, and the "output circuit" is the
path for the current to flow in the transistor between collector
13C and emitter 13E. In my silicon controlled rectifier 28, for
example, the "input circuit" is the path for the current to flow in
the rectifier between cathode 28C and gate 28G, and the "output
circuit " is the path for the current to flow in the rectifier
between cathode 28C and anode 28A.
DESCRIPTION OF FIG. 11
The circuit of FIG. 11 is a modification of FIGS. 3,9 and 10 and
differs from these circuits in the following respects: In FIG. 11 a
resistor 53 is connected across capacitor 26. Numeral 54 designates
an inductance having a magnetic core connected in series with a
semi-conductor diode, designated by numeral 55, and this
combination in series is connected, as shown in FIG. 11, across
capacitor 26. Numeral 56 designates a semi-conductor diode and is
connected, as shown, across the input circuit 13B to 13E of
transistor 13. The transformer 21A of FIG. 11 is the same in
structure and function as the transformer 21A of FIG. 10. Other
differences between FIG. 11 and FIGS. 3,9 and 10 may be noted by
referring to the drawings and the following description.
Breaker contacts 19A and 19B, resistor 18, magnetic control device
48, and diode 51 function in a manner similar to that described for
these said elements in the description of FIG. 9, to cause the
output circuit of silicon controlled rectifier 28 to be conductive
upon the opening of contacts 19A and 19B.
Assuming for the present that ignition switch 12 is closed, that
breaker contacts 19A and 19B are closed, and that capacitor 26 has
a negative charge possessing energy on its right hand plate or
terminal that is connected to cathode electrode 28C, the operation
of FIG. 11 is as follows.
Diode 55 prevents said charge from discharging through inductance
54 and diode 24 prevents said charge from discharging through
secondary winding 23A. Resistor 53 will leak off some of said
charge, but the resistor 53 is selected to have such a large value
of resistance that the operation of FIG. 11 will be affected by
such leakage to only a small degree. The sole function of resistor
53 is to discharge capacitor 26 when ignition switch 12 is
open.
Now beginning at a time when contacts 19A and 19B have just opened
and the output circuit 28C to 28A of silicon controlled rectifier
28 has become conductive, a current will flow out of the right hand
plate or terminal of capacitor 26 and through the output circuit
28C to 28A, through primary winding 30, through ground, through
battery 11, through ignition switch 12, through semi-conductor
diode 56 and into the left hand plate or terminal of capacitor 26.
The flow of this current in primary winding 30 will fire spark plug
35 in the same manner as described in the description of FIG. 9.
For purposes of explanation and claiming this circuit just
described may be referred to as "the capacitor discharge circuit".
All the energy of capacitor 26 is not used during the flow of this
last mentioned current and when this current has ceased, capacitor
26 will be left with a reverse or negative charge on its left hand
plate or terminal that is connected to base electrode 13B. The
presence of this negative charge on the left hand plate or terminal
of capacitor 26 causes the output circuit of silicon controlled
rectifier 28 to become non-conductive and said output circuit will
remain non-conductive until the next opening of breaker contacts
19A and 19B.
After the firing of spark plug 35 the reverse or negative charge on
the left hand plate or terminal of capacitor 26 and the voltage of
battery 11 will aid each other to cause a current to flow, out of
the negative left hand plate or terminal of capacitor 26, through
the input circuit of transistor 13, through ignition switch 12,
through battery 11, through ground, through secondary winding 23 A,
through semiconductor diode 24, and into the right hand plate or
terminal of capacitor 26. For purposes of explanation and claiming
this circuit just described may be referred to as "the charging
circuit". This current flowing in the input circuit of transistor
13 causes the output circuit of transistor 13 to be conductive and
then battery 11 causes a relatively larger current to flow out of
its negative terminal, through ground, through primary winding 22A,
through the output circuit of transistor 13, through ignition
switch 12, and back into the positive terminal of battery 11. The
flow of this current in primary winding 22A will energize
transformer 21A and cause a voltage to be induced in secondary
winding 23A. Flux that is common to all the windings on a
transformer is sometimes referred to as mutual magnetic flux, and
it is this mutual magnetic flux that produces said voltage in
secondary winding 23A. Secondary winding 23A is wound to have such
a magnetic sense that the said induced voltage causes its upper end
to be negative in respect to its lower or grounded end. This said
induced voltage in secondary winding 23A, thus having the proper
polarity, causes the current flowing in the charging circuit to
continue to flow until capacitor 26 is again fully charged, with
its right hand plate or terminal being negative (which is the
correct polarity for firing spark plug 35). During the time this
current is flowing in the charging circuit to charge capacitor 26
it maintains the output circuit of transistor 13 conductive because
it flows through the input circuit 13B to 13E of transistor 13.
SInce the output circuit of transistor 13 is conductive during the
charging of capacitor 26 current flows in primary winding 22A
during this same period of time and energizes transformer 21A which
energizes the charging circuit to change capacitor 26.
The current flowing in the charging circuit which includes
secondary winding 23A and the larger current flowing in primary
winding 22A, during the period of time the output circuit of
transistor 13 is conductive, are pulses of current. Both pulses of
current vary with respect to time substantially as illustrated by
FIG. 2B.
During the period of time, substantially illustrated by FIG. 2B,
that the currents flowing in primary winding 22A and secondary
winding 23A are increasing toward a maximum value, energy is being
stored in the leakage magnetic fields associated with these
windings. During the period of time that said currents are
decreasing to a minimum value, said leakage magnetic fields are
releasing said stored energy and said released energy is being
caused to be transferred into storage capacitor 26.
The leakage inductances designed and built into transformer 21A
limits the maximum value of the current flowing in primary winding
22A and hence limits the current flowing in the output circuit of
transistor 13 and also limits the maximum value of the current
flowing in the charging circuit. It is desirable to make the
electrical resistance, of the two circuits and components involved
in charging storage capacitor 26, as small as possible. Storage
capacitor 26 is charged with a voltage substantially greater than
the voltage of battery 11 as multiplied by the turn ratio of the
transformer 21A by reason of the inclusion of the described leakage
inductances in the transformer 21A. The smaller the losses in the
magnetic core of transformer 21A and the smaller the electrical
resistances of the two circuits and components which are involved
in charging capacitor 26, the greater the voltage with which the
storage capacitor 26 will be charged.
It may be noted that when switch 12 is closed and capacitor 26 is
uncharged that battery 11 will cause a current to flow in the said
charging circuit and hence in the input circuit of transistor 13.
As a result of this current flow in the input circuit of transistor
13 the output circuit of transistor 13 will become conductive. When
the output circuit of transistor 13 is thus conductive, capacitor
26 is charged in the manner described above.
During the period of time that the output circuit of transistor 13
is conductive and current is flowing in primary winding 22A from
battery 11 a magnetic field is built up in transformer 21A. When
the output circuit of transistor 13 becomes non-conductive and cuts
off said current in primary winding 22A, the magnetic field
existing in transformer 21A collapses and causes an induced current
to flow out of the upper end of primary winding 22A, that is
connected to collector electrode 13C, through resistor 27, through
ground, and into the lower end of primary winding 22A. The function
of resistor 27 is to prevent harm to transistor 13 by completing a
circuit for said induced current to flow in, and resistor 27 also
dissipates the energy of the magnetic field existing in transformer
21A when the output circuit of transistor 13 becomes
non-conductive. Resistor 27 is chosen to have a value of resistance
low enough that the voltage developed across the substantially
non-conductive output circuit of transistor 13 is not great enough
to harm transistor 13.
After the firing of spark plug 35 the above said reverse or
negative charge on the left hand plate or terminal of capacitor 26
causes a current to flow through inductance 54 and diode 55. As a
result of this current flow a portion of said reverse charge is
transferred to the right hand plate or terminal of capacitor 26
(which is the proper condition of capacitor 26 for firing spark
plug 35). Thus the function of the combination of inductance 54 and
diode 55 is to provide a partial recharging of capacitor 26.
Another portion of said reverse charge is transferred to the right
hand plate or terminal of capacitor 26 via the said charging
circuit as described above. It is to be understood that the circuit
of FIG. 11 will function without inductor 54 and diode 55. The
advantages of including inductor 54 and diode 55 in the circuit of
FIG. 11 are that smaller currents will flow in the windings of
transformer 21A and less current will flow in the output circuit of
transistor 13.
DESCRIPTION OF FIG. 12
FIG. 12 is a partial schematic circuit diagram and is a
modification of FIG. 11. In FIG. 12 the combination of transformer
21 and inductance 38 is employed to perform the same function that
transformer 21A performs in FIG. 11. Transformer 21 and inductance
38 are connected as shown. It is to be understood that transformer
21 is a conventional power transformer and that a conventional
power transformer is one which is constructed to minimize the value
of the leakage inductances associated with the windings. An example
of a small conventional power transformer would be the power supply
transformer of a home radio or television receiver. Transformer 21
and inductance 38 affect the circuit of FIG. 12 in a manner similar
to the way they affect the circuit of FIG. 3. The operation of FIG.
12 is similar to the operation of FIG. 11.
DESCRIPTION OF FIG. 13
FIG. 13 is a partial schematic circuit diagram and is a
modification of FIG. 11. In FIG. 13 the combination of transformer
21 and inductance 52 is employed to perform the same function that
transformer 21A performs in FIG. 11. Transformer 21 and inductance
52 are connected as shown. Transformer 21 and inductance 52 affect
the circuit of FIG. 13 in a manner similar to the way they affect
the circuit of FIG. 9. The operation of FIG. 13 is similar to the
operation of FIG. 11.
The present disclosure includes that contained in the appended
claims, as well as that of the foregoing description.
Although this invention has been described in its preferred form
with a certain degree of particularly, it is understood that the
present disclosure of the preferred form has been made only by way
of example and that numerous changes in the details of construction
and the combination and arrangement of parts may be resorted to
without departing from the spirit and the scope of the invention as
hereinafter claimed.
* * * * *