U.S. patent number 3,611,025 [Application Number 04/763,645] was granted by the patent office on 1971-10-05 for ignition system utilizing transistor for internal combustion engines.
This patent grant is currently assigned to Povaske Strojarne, narodny Podnik. Invention is credited to Karol Longauer.
United States Patent |
3,611,025 |
Longauer |
October 5, 1971 |
IGNITION SYSTEM UTILIZING TRANSISTOR FOR INTERNAL COMBUSTION
ENGINES
Abstract
A transistor has a control electrode connected to the feedback
winding of an ignition transformer. A storage capacitor is
connected to the primary winding of the ignition transformer via
the input-output path of the transistor and a starting
stabilization diode.
Inventors: |
Longauer; Karol (Bratislava,
CS) |
Assignee: |
Povaske Strojarne, narodny
Podnik (Povazska, Bystrica, CS)
|
Family
ID: |
5424413 |
Appl.
No.: |
04/763,645 |
Filed: |
September 30, 1968 |
Foreign Application Priority Data
|
|
|
|
|
Oct 24, 1967 [CS] |
|
|
PV 7514-67 |
|
Current U.S.
Class: |
315/209T;
315/209CD; 315/78; 315/223 |
Current CPC
Class: |
F02P
1/086 (20130101) |
Current International
Class: |
F02P
1/08 (20060101); F02P 1/00 (20060101); F02p
003/08 (); F02p 007/06 () |
Field of
Search: |
;315/78,200,201,206,208,209,211,212,214,219,223,29T,29CD,29M,218
;307/10,132,133 ;317/96 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Lake; Roy
Assistant Examiner: LaRoche; E. R.
Claims
What we claim is:
1. An ignition system, comprising
a supply circuit,
starting pulse means,
an ignition transformer having a primary winding, a secondary
winding connected to an igniting device and a feedback winding,
a semiconductor switching device having input and output
electrodes, an input-output path and a control electrode connected
to the feedback winding of said ignition transformer,
a starting stabilization diode connected to said starting pulse
means, and
a storage capacitor supplied by said supply circuit and connected
in parallel to the primary winding of said ignition transformer and
the input-output path of said semiconductor switching device and
said starting stabilization diode.
2. An ignition system as claimed in claim 1, wherein said
semiconductor switching device comprises a transistor.
3. An ignition system as claimed in claim 2, further comprising a
starting pulse circuit connected in parallel with said starting
stabilization diode for providing a starting pulse.
4. An ignition system as claimed in claim 2, further comprising a
shaping capacitor connected in parallel with said starting
stabilization diode, a diode and a starting pulse circuit connected
in parallel with said starting stabilization diode for providing a
starting pulse, said starting pulse circuit comprising an
alternator having a starting coil connected via said diode to said
shaping capacitor
5. An ignition system as claimed in claim 4, further comprising a
variable capacitor mechanically coupled to the alternator of said
starting pulse circuit and connected to said storage capacitor via
the primary winding of said ignition transformer.
6. An ignition system as claimed in claim 4, wherein said
transistor has an input-control path, and further comprising a
variable capacitor mechanically coupled to the alternator of said
starting pulse circuit and connected to said storage capacitor via
the input-control path of said transistor and said starting
stabilization diode and the primary winding of said ignition
transformer.
7. An ignition system as claimed in claim 4, wherein the alternator
of said starting pulse circuit has a supply coil, said supply coil
and the starting coil of said alternator being positioned in
operative inductive proximity with each other.
8. An ignition system as claimed in claim 4, further comprising a
rectifying diode and wherein the alternator of said starting pulse
circuit has a supply coil connected to said ignition transformer in
the first half cycle of the alternator current via said rectifying
diode and said storage capacitor and in the second half cycle of
said alternator current via said diode, the starting stabilization
diode of said starting pulse circuit and said shaping
capacitor.
9. An ignition system as claimed in claim 4, wherein the alternator
of said starting pulse circuit has a galvanomagnetic resistor
connected to said storage capacitor via the primary winding of said
ignition transformer.
Description
DESCRIPTION OF THE INVENTION
The present invention relates to an ignition system for internal
combustion engines. More particularly, the invention relates to an
ignition system utilizing a transistor for internal combustion
engines.
Electronic ignition systems have been developed due to more
stringent requirements for the output performance of high-speed
internal combustion engines having a high compression ratio and
more stringent requirements for increasing the operational
reliability of ignition circuits and for reducing control and
maintenance requirements.
Since electronic ignition systems or circuits of newly developed
type are not yet widely used, primarily due to economic reasons,
battery and magneto ignition systems having contacts are in use.
Although the better quality of electronic ignition systems is not
in doubt, the advantages of such systems do not outweigh the high
production costs thereof.
Ignition systems of known type utilizing a mechanical contact
breaker or interrupter have a number of disadvantages which are
particularly pronounced in small cylinder capacity internal
combustion engines which provide greater power primarily by an
increase in speed. A mechanical interrupter functions very
unreliably at higher speeds such as, for example, 10,000
revolutions per minute. The use of two interrupters has not proven
to be of advantage. The unreliability of a mechanical interrupter
is due to pitting and fouling of the interrupter contacts and cam
and arm vibration. These disadvantages are overcome by electronic
ignition systems, especially of the contact type.
There are three basic known types of electronic ignition systems. A
first, transistorized ignition system, is controlled by a
mechanical interrupter. A second, transistorized ignition system,
is controlled by an electrical pulse which is produced
electromagnetically, photoelectrically or piezoelectrically. A
third, capacitive ignition system, utilizes a capacitor which
discharges into the primary circuit of an ignition coil. There are
other types of ignition systems which are not in general use such
as, for example, various oscillatory systems and the like. Each
type of electronic ignition system has advantages and
disadvantages.
A transistorized ignition system of the type controlled by a
mechanical interrupter is the most simple in design, may be adapted
to internal combustion engines of current type with facility and
does not require more considerable adaptations and equipment,
except a special ignition coil having a greater step-up ratio.
However, transistors meeting considerable requirements are
necessary for reliable operation of the system. In a system of this
type, the transistor only relieves the usual mechanical interrupter
by providing the switching-in interruption function of electrical
currents of large magnitudes of 8 to 12 amps. There are also
high-voltage peaks which exceed the permissible magnitude and must
be eliminated by, for example, Zener diodes. The transistor may be
severely damaged or destroyed. Thus, for example, the mechanical
vibration of contacts may cause the emitter-collector junction of
the transistor to become loaded with considerably higher electrical
magnitudes. Furthermore, if the ignition system is disconnected by
the ignition key-operated switch at an instant when the mechanical
interrupter is switched on, there is a considerable strain.
For various reasons, the transistor is required to have high
parameters. Since the transistor must be carefully selected, it is
costly. An electronic ignition system of the first type is
unsuitable for internal combustion engines operating at very high
speeds, because the mechanical interrupter is unsatisfactory for
mechanical reasons, even if it is not under an electrical strain.
There are also inaccuracies in spark advance at high speeds. The
entire system, including the transistor, is heated by a high power
loss and the space occupied by said system is increased by the
inclusion of the required cooling areas.
The second type of ignition system is controlled without contacts.
This requires additional amplifying units, and therefore increases
the circuit complexity and cost, and reduces reliability. The
principal advantage of the second type of system is its desirable
operation in the entire speed range. Another advantage is a reduced
possibility of severe damage or destruction of the transistor.
Neither of the first and second type of ignition system provides a
solution for the problem of increasing the rate of increase of the
ignition voltage required for igniting partly fouled spark plugs.
This problem is solved by the third type of electronic ignition
system which functions on the principle of capacitor discharge. The
capacitor is charged to a voltage of 300 to 1,000 volts via either
a mechanical contact or an electronic switch such as, for example,
a thyristor or thyratron or gas-filled discharge tube, and
discharges into an ignition coil. Although the third type of system
is the best of the three types, it is also the costliest. The cost
may be reduced by utilizing a gas-filled discharge tube instead of
a more costly thyristor. A discharge tube has a shorter life than a
thyristor and requires a considerably higher voltage such as, for
example, approximately 220 volts, for the starting pulse. Although
the pulse current and power are small, a voltage of 220 volts may
be produced only by additional amplifying units or a mechanical
interrupter. A mechanical interrupter is less expensive than
amplifying units and is therefore more frequently utilized.
The common disadvantage of the three types of electronic ignition
systems is their high production costs. A suitable ignition system
must therefore be economical in cost as well as technically
advantageous.
The principal object of the present invention is to provide a new
and improved ignition system.
An object of the present invention is to provide an ignition system
which combines the advantages of the three types of electronic
ignition systems.
An object of the present invention is to provide an ignition system
of which the transistor cannot be damaged or destroyed.
An object of the present invention is to provide an ignition system
which provides a rapid increase of the ignition voltage and thereby
provides ignition for partly fouled spark plugs.
An object of the present invention is to provide an ignition system
the transistor of which may be made conductive by applying a
voltage pulse of approximately 0.5 volt and a current of
approximately 10 ma. to a starting diode.
An object of the present invention is to provide an ignition system
having an auxiliary feedback winding on the ignition transformer
for providing positive feedback to the control electrode of a
transistor thereby rapidly switching the transistor to its
conductive condition, so that there is no need for amplifying units
and miniature starting induction coils may be utilized for
starting.
An object of the present invention is to provide an ignition system
utilizing components of nonexacting tolerances and having low
production costs, which are comparable with those of known
mechanical interrupter systems.
An object of the present invention is to provide an ignition system
of low cost which may be used in low-cost vehicles.
An object of the present invention is to provide an ignition system
which may utilize with reliability transistors of lower quality and
looser tolerances than the usual rated tolerances.
An object of the present invention is to provide a transistorized
ignition system having a high efficiency of operation.
An object of the present invention is to provide an ignition system
having very low energy consumption, such as 0.3 watts with 600
sparks and 6 watts with 12,000 sparks, such energy being dissipated
by the components of the system and producing a magnetic field in
the ignition transformer.
An object of the present invention is to provide an ignition system
having a transistor whose temperature, for practical purposes, is
not increased above the ambient temperature, so that no cooling is
required.
An object of the present invention is to provide an ignition system
including a transistor which functions reliably when heated by an
external source to 80.degree. C., so that it operates reliably
under an engine hood of a vehicle.
An object of the present invention is to provide an ignition system
for low-capacity, high-speed engines which functions perfectly,
starts the engine at low ambient temperatures and has an ignition
accuracy of .+-.0.5 percent over the entire speed range.
An object of the present invention is to provide an ignition system
which operates to fire an engine in a manner whereby the engine
runs regularly and elastically, starts well with direct
transmission from a low speed without jerking, is immune to engine
vibrations, requires practically no maintenance and the functional
life of the spark plugs is considerably lengthened.
Another object of the present invention is to provide an ignition
system which functions with efficiency, effectiveness and
reliability.
In accordance with the present invention, an ignition system
comprises a supply circuit, starting pulse means an ignition
transformer having a primary winding connected to an igniting
device, a secondary winding and a feedback winding. A semiconductor
switching device has input and output electrodes, an input-output
path and a control electrode connected to the feedback winding of
the ignition transformer. A storage capacitor supplied by the
supply circuit is connected in parallel to the primary winding of
the ignition transformer via the input-output path of the
semiconductor switching device and a starting stabilization diode
connected to the starting pulse means. The semiconductor switching
device comprises a transistor.
A shaping capacitor is connected in parallel with the starting
stabilization diode. A starting pulse circuit is connected in
parallel with the starting stabilization diode for providing a
starting pulse. The starting-pulse circuit comprises an alternator
having a starting coil connected via a diode to the shaping
capacitor. The alternator of the starting pulse circuit has a
supply coil, and the supply coil and the starting coil of the
alternator are positioned in operative inductive proximity with
each other. The alternator of the starting pulse circuit has a
supply coil connected to the ignition transformer in the first half
cycle of the alternator current via a rectifying diode and the
storage capacitor and in the second half cycle of the alternator
current via a diode, the starting stabilization diode of the
starting-pulse circuit and the shaping capacitor.
In one embodiment of the invention, the alternator of the
starting-pulse circuit has a galvanomagnetic resistor connected to
the storage capacitor via the primary winding of the ignition
transformer.
In another embodiment of the invention, a variable capacitor is
mechanically coupled to the alternator of the starting pulse
circuit and is connected to the storage capacitor via the primary
winding of the ignition transformer.
In another embodiment of the invention, a variable capacitor is
mechanically coupled to the alternator of the starting pulse
circuit and is connected to the storage capacitor via the
input-control path of the transistor and the starting stabilization
diode and the primary winding of the ignition transformer.
The principal feature of the ignition system of the present
invention is that it includes a storage capacitor which is
connected to the primary winding of the ignition transformer via a
transistor and a starting stabilization diode. The control
electrode of the transistor is connected to a feedback winding of
the ignition transformer. The starting pulse circuit is connected
in parallel with the starting stabilization diode.
The charged storage capacitor of the ignition system of the present
invention discharges via the transistor. The ignition is started
without contacts and without additional amplifying units, by
electrical pulses. The transistor may be of the most inexpensive
type available.
The entire ignition system of the present invention may be embedded
in plastic to protect it from the heat of its environment.
In order that the present invention may be readily carried into
effect, it will now be described with reference to the accompanying
drawings, wherein:
FIG. 1 is a circuit diagram of an embodiment of the ignition system
of the present invention;
FIG. 2 is a circuit diagram of another embodiment of the ignition
system of the present invention;
FIG. 3 is a circuit diagram of another embodiment of the ignition
system of the present invention;
FIG. 4 is a circuit diagram of another embodiment of the ignition
system of the present invention;
FIG. 5 is a circuit diagram of another embodiment of the ignition
system of the present invention;
FIG. 6 is a circuit diagram of another embodiment of the ignition
system of the present invention; and
FIG. 7 is a circuit diagram of still another embodiment of the
ignition system of the present invention.
In the FIGS., the same components are identified by the same
reference numerals.
In FIG. 1, the supply coil and the starting coil of an alternator
are in independent circuits, separated electrically and spatially,
but synchronized with each other. In FIG. 1, a storage capacitor C1
is connected to the collector or output electrode of a transistor
T. If the transistor T is of PNP type, as in the example of FIG. 1,
the collector electrode is negative. A rectifying diode D1 in the
supply circuit is therefore connected in the forward direction for
the negative half wave of the supply voltage from a supply coil L1
of an alternator A.
One end of the supply coil L1 is connected to a point Z at ground
potential. The point at ground potential may comprise, for example,
the engine frame (not shown in the FIGS.). The rectifying diode D1
is connected between the other end of the supply coil L1 and the
collector electrode C of the transistor T. One plate of the storage
capacitor C1 is connected to a common point in the connection
between the rectifying diode D1 and the transistor T. The other
plate of the storage capacitor C1 is connected to ground Z via the
primary winding L2 of an ignition transformer TR1. The ignition
transformer TR1 also has a secondary winding L3 and an auxiliary
feedback winding L4.
An electrical voltage is produced in the supply coil L1 of the
alternator A during rotation of the rotor R of said alternator. The
voltage produced in the supply coil L1 stores energy in the storage
capacitor C1 during each negative half wave, by charging said
capacitor. The circuit parameters are so selected that the voltage
across the storage capacitor C1 corresponds to the cutoff voltage
V.sub.CBO of the transistor T. The input or emitter electrode E of
the transistor T is connected to ground Z via a starting
stabilization diode D2.
The starting stabilization diode D2 is connected in series circuit
arrangement with the auxiliary feedback winding L4 of the ignition
transformer TR1 in the emitter-base or input-control path of the
transistor T. The starting stabilization diode D2 performs two
functions. The first function of the starting stabilization diode
D2 is the production of a small voltage of approximately 0.5 volt,
provided by the supply of a residual current I.sub.CBO through the
transistor T from the charged storage capacitor C1 at a time when
said transistor is blocked or in its nonconductive condition. This
small voltage, which is positive in the case of the present
example, is applied to the control or base electrode B of the
transistor T via the feedback winding L4 of the ignition
transformer TR1.
The application of the voltage of approximately 0.5 volt to the
base electrode B of the transistor T reduces the residual current
I.sub.CE to I.sub.CBO and the cutoff voltage V.sub.CE of said
transistor is substantially reduced to V.sub.CBO. The second
function of the starting stabilization diode D2 is the provision of
a very simple and reliable source of starting pulses. The source of
starting pulse is the starting circuit, which comprises a starting
coil L5 of the alternator A. The starting coil L5 is connected at
one end to ground Z and is connected at its other end to the
emitter electrode E of the transistor T via a diode D3 and a
capacitor C2.
The starting coil L5 of the alternator A is spatially positioned
and connected with such polarities relative to the supply coil L1
of said alternator, that, in the case of the present example, said
starting coil produces a positive starting pulse when there is a
positive supply voltage in said supply coil, so that the rectifying
diode D1 is blocked or in its nonconductive condition. The diode D3
transfers a positive starting pulse only if the magnitude of such
starting pulse is greater than the characteristic threshold voltage
of said diode such as, for example, approximately 0.5 volt for a
ceramic diode. This eliminates undesirable pulses which may occur
in the alternator A.
The capacitor C2 is connected in parallel with the starting
stabilization diode D2 and functions to substantially reduce the
magnitude of the required starting pulse. The capacitor C2 shapes
the pulses in a suitable manner and, with the inductance of the
starting coil L5 of the alternator, produces a spark or flash. The
inductance of the starting coil L5, at the instant of starting,
cancels the bias voltage produced across the starting stabilization
diode D2 which increases the residual current suddenly from
I.sub.CBO to I.sub.CE via the transistor T. At the same instant,
the positive starting current pulse, applied to the input electrode
E and the control electrode B of the transistor T, switches said
transistor to its conductive condition.
The starting current pulse, which is greater in magnitude than the
residual current I.sub.CBO, passes through the primary winding L2
of the ignition transformer TR1 and produces in the iron core of
said transformer a magnetic field which induces a pulse in the
auxiliary feedback winding L4 of said ignition transformer. The
pulse induced in the feedback winding L4 has a polarity which is
such that there is positive coupling which tends to make the
transistor T more conductive. This function is very rapid.
All the energy stored in the storage capacitor C1 is transformed
into a magnetic field in the ignition transformer TR1. This results
in the production of a high voltage, of approximately 25 kilovolts,
in the secondary winding L3 of the ignition transformer TR1, due to
the large number of turns of said winding. The 25 kilovolt voltage
produced by the secondary winding L3 produces a spark in the spark
plug SP. At such time, the rectifying diode D1 is blocked or in
nonconductive condition, so that no energy is transferred from the
supply coil L1 of the alternator A to the circuit of the transistor
T. This prevents the circuit comprising the transistor T, the
storage capacitor C1 and the ignition transformer TR1 from
oscillating and said transistor is switched to its nonconductive
condition. The circuit is then in its deenergized or inactive
condition and the storage capacitor C1 is ready for charging with
energy form the supply coil L1 of the alternator A via the
rectifying diode D1 when the negative half wave of the supply
voltage forms. The process is repeated when a positive pulse is
produced by the starting coil L5 of the alternator A.
In the embodiment of FIG. 1, the supply voltage and the starting
pulse are synchronized by the positions or locations and polarities
of the supply coil L1 and the starting coil L5 relative to each
other. The internal impedance of the supply coil L1 of the
alternator A may therefore be as small as required and is
determined only by the admissible magnitude of the current pulse of
the rectifying diode D1.
It may be seen that the principle of operation of the circuit
arrangement of FIG. 1 is such that the maximum voltage which may be
produced in the circuit of the transistor T is the voltage of the
storage capacitor C1. The storage capacitor C1, however, has a
capacitance of several microfarads, and random pulses would have to
have considerable magnitude to increase the voltage on the
collector and emitter electrodes of the transistor T to an
undesirable extent. Since the ignition system of the present
invention is completely separated from the general network of the
vehicle in which it is utilized, the voltage cannot increase to an
undesirable magnitude. The number of turns of the auxiliary
feedback winding L4 of the ignition transformer TR1 is selected so
that the transistor T is switched to conductive condition within a
minimum period of time and to prevent the pulse voltage between the
emitter and base electrodes of said transistor from exceeding the
required magnitude. This is achieved without difficulty.
Very good operation of the ignition system of the present invention
was attained, even with a transistor having a cutoff voltage
V.sub.CE =25 volts at R.sub.BE =0, with a current I.sub.CE =2 ma.,
at a temperature of 25.degree. C., and with a current I.sub. CE =5
ma. at R.sub.VE =0, V.sub.CE =40 volts, at a temperature of
25.degree. C. It is thus seen that even low-quality transistors
function successfully at a voltage of 130 volts on the storage
capacitor C1.
If for any outside reason whatsoever, a voltage appears at the
storage capacitor C1 which may damage the transistor T, the
residual current I.sub.CE is suddenly increased in magnitude. Under
the effect of the positive feedback in the auxiliary feedback
winding L4 of the ignition transformer TR1, the increased residual
current I.sub.CE causes spontaneous conduction of the transistor T,
so that the storage capacitor C1 commences to discharge
instantaneously and the voltage is reduced to zero. This prevents
damage to or destruction of the transistor T. The internal
impedance of the supply coil L1 of the alternator A is always at
least large enough that, in such a special case, damage of the
transistor T by short circuit current is prevented. Such a
situation does not occur under practical operating conditions, but
is described in order to illustrate the protection of the
transistor from damage, as well as the reliability of operation of
the ignition system of the present invention.
In FIG. 2, a single alternator coil functions as the supply coil
and the starting coil. The embodiment of FIG. 2 differs from that
of FIG. 1 only in the manner of producing a starting pulse. The
supply coil L1 of the alternator A functions also to provide a
starting pulse. When a positive voltage is produced and the
rectifying diode D1 is blocked, the starting pulse is transmitted
via the diode D3 to the shaping capacitor C2 and the starting
stabilization diode D2. If the preceding negative half wave from
the supply coil L1 of the alternator A has charged the storage
capacitor C1 via the rectifying diode D1, the positive half wave
may switch the transistor T to its conductive condition. Thus,
during one revolution, as many sparks are provided as there are
pairs of poles N and S on the rotor R2 of the alternator A2. In the
embodiment of FIG. 2, the rotor R2 of the alternator A2 has two
pairs of poles N and S, so that two sparks are produced in each
revolution.
In FIG. 3, the alternator and the spark distributor form a single
unit. In the embodiment of FIG. 3, the rotor R of the alternator A
has four pairs of poles N and S, so that four sparks are produced
in each revolution. The alternator A is directly coupled
mechanically to a spark distributor SD. This provides an ignition
system for a four stroke, four cylinder engine. The systems of FIG.
2 and FIG. 3 require, apart from the engine frame, which functions
as the ground lead, only a single electrical conductor to
interconnect the supply and starting coil L1 of the spark
distributor SD with the transistor circuit. This is of great
importance regarding service and maintenance.
In FIG. 4, the ignition system is supplied with power from one
phase of a standard three-phase alternator and the voltage is
increased to the required magnitude by a transformer. The starting
coil is included with the spark distributor. In the embodiment of
FIG. 4, the power is supplied by a single phase X of a standard
three-phase alternator A3. A transformer TR2 has a primary winding
L6 and a secondary winding L7 which replaces the supply coil L1 of
the embodiment of FIG. 1.
The starting coil L5 is independent from the supply transformer TR2
and is included with the spark distributor SD. Since it is
impossible to synchronize the supply voltage provided by the
secondary winding L7 of the transformer TR2 with the voltage pulse
provided by the starting coil L5 of the spark distributor SD, the
internal impedance of said secondary winding has to be at least 400
ohms, to prevent the transistor circuit from oscillating under the
influence of the positive feedback.
The current from the secondary supply winding L7 must not exceed a
magnitude which maintains the positive feedback. This may be
accomplished by the proper selection of the transformer TR2.
Operation is then as reliable as in the embodiments of FIGS. 1, 2
and 3. Therefore, any suitable voltage and power source may be
utilized in the embodiment of FIG. 4 if said source has an internal
impedance greater than 400 ohms, and it is not necessary that the
supply voltage and the starting pulse be synchronized. A suitable
power source may comprise, for example, a transistor converter or
an oscillatory or vibratory converter.
In FIG. 5, the starting circuit comprises a galvanomagnetic
resistor rather than a starting coil, said resistor having a
resistance value which depends upon the intensity of the magnetic
field. In the embodiment of FIG. 5, a galvanomagnetic resistor GR
is positioned in the magnetic field of the rotor R of the
alternator A. The ohmic resistance value of the galvanomagnetic
resistor GR is dependent upon the intensity of the magnetic
field.
The galvanomagnetic resistor GR is connected to the storage
capacitor C1 and to the starting stabilizing diode D2. When the
resistance value of the galvanomagnetic resistor GR varies due to a
variation in the magnetic field of the rotor R, an electrical pulse
is transmitted from the storage capacitor C1 through said
galvanomagnetic resistor and the primary winding L2 of the ignition
transformer TR1. Such pulse, with the assistance of the feedback
winding L4 of the ignition transformer TR1, switches the transistor
T to its conductive condition, and the storage capacitor C1
discharges into the primary winding L2 of said ignition
transformer. In other respects, the embodiment of FIG. 5 is the
same as the other described embodiments of the present invention in
operation.
In FIG. 6, a variable capacitor is connected between the storage
capacitor and the starting stabilization diode. In the embodiment
of FIG. 6, a variable capacitor C3 having a variable capacitance is
mechanically coupled to and rotates with the rotor R of the
alternator A and is electrically connected between the storage
capacitor C1 and the starting stabilization diode D2. If the
capacitance of the variable capacitor C3 varies rapidly, for
example, if said capacitance increases, said variable capacitor is
charged by current from the storage capacitor C1 via the primary
winding L2 of the ignition transformer TR1.
The charging current of the variable capacitor C3 provided by the
storage capacitor C1 and the auxiliary feedback winding L4 of the
ignition transformer TR1 switch the transistor T to its conductive
condition. When the transistor T is conductive, the storage
capacitor C1 discharges into the primary winding L2 of the ignition
transformer TR1. In other respects, the ignition system of FIG. 6
functions in the same manner as the previously described
embodiments.
In FIG. 7, a variable capacitor is electrically connected between
the collector and base electrodes of the transistor. In the
embodiment of FIG. 7, the variable capacitor C3 is mechanically
coupled to and rotates with the rotor R of the alternator A and is
electrically connected between the collector and base electrodes of
the transistor T. If the capacitance of the variable capacitor C3
increases rapidly, the charging current of the storage capacitor C1
flows through the control or base electrode B and the input or
emitter electrode E of the transistor T and through the starting
stabilization diode D2 to the primary winding L2 of the ignition
transformer TR1.
The charging current pulse of the variable capacitor C3 and the
auxiliary feedback winding L4 of the ignition transformer TR1
switch the transistor T to its conductive condition. When the
transistor T is conductive, the storage capacitor C1 discharges
into the primary winding L2 of the ignition transformer TR1.
Otherwise, the ignition system of FIG. 7 functions in the same
manner as the previously described embodiments.
If the transistor T is of NPN type, the polarities of the diodes
D1, D2 and D3 must be reversed. The positive half wave of the
current provided by the supply coil L1 of the alternator A is
utilized. The starting pulse then has a negative polarity.
The ignition system of the present invention reveals some
functional deficiencies of engines such as, for example, the engine
filling with a mixture, faults in the fuel system, and the like.
This permits further improvements to be made in the engine. Some of
the deficiencies may be due to operation with an ignition system of
known type, because it is difficult to determine the actual nature
of the deficiency, especially in engines which have already run a
considerable distance and in which decrease in output power is due
to a variety of reasons.
While the invention has been described by means of specific
examples and in specific embodiments, we do not wish to be limited
thereto, for obvious modification will occur to those skilled in
the art without departing from the spirit and scope of the
invention.
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