U.S. patent number RE28,904 [Application Number 05/617,366] was granted by the patent office on 1976-07-13 for method and apparatus for testing internal combustion engines.
This patent grant is currently assigned to Scans Associates, Inc.. Invention is credited to Richard C. Maisonville.
United States Patent |
RE28,904 |
Maisonville |
July 13, 1976 |
Method and apparatus for testing internal combustion engines
Abstract
This application discloses a method and apparatus for measuring
and/or adjusting the timing angle of internal combustion engines.
The method of measuring the timing angle comprises the steps of
running the engine and producing voltage pulsations of uniform time
frequency against which are simultaneously taken measurements of
two values: first, the measurements of engine speed by counting the
number of pulsations for one full and precise revolution of the
engine from top dead center to top dead center of one selected
cylinder, and simultaneously counting the number of pulsations from
the moment the spark plug of the selected cylinder fires to the top
dead center (for the advance firing) or from the top dead center to
the moment of firing of the spark plug (for retarded firing).
Counting two of such values enables the testing personnel to
express the timing angle in degrees and to have the RPM of the
engine at the time of testing, neither of which would be available
if only one of such two values were measured. The disclosed test
apparatus also provides a mechanism responsive to such
measurements, which mechanism gives a readout of the revealed
timing angle and compares it with the set range of timing angles,
and a servo-mechanism which automatically adjusts the obtained
timing angle to the desired value within such set angle. In one of
its aspects the application discloses a test stand which may be
conveniently used for tests, and a conveyor connecting into a
single system a plurality of such stands to test the engines,
particularly but not exclusively automobile engines under
production conditions, as the system may also be used to test
engines when operating in an automobile. .Iadd.
Inventors: |
Maisonville; Richard C.
(Detroit, MI) |
Assignee: |
Scans Associates, Inc.
(Livonia, MI)
|
Family
ID: |
26896274 |
Appl.
No.: |
05/617,366 |
Filed: |
September 29, 1975 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
200974 |
Nov 22, 1971 |
03763420 |
Oct 2, 1973 |
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Current U.S.
Class: |
324/392 |
Current CPC
Class: |
F02P
17/04 (20130101); G06F 7/62 (20130101) |
Current International
Class: |
G06F
7/60 (20060101); F02P 17/04 (20060101); F02P
17/00 (20060101); G06F 7/62 (20060101); F02P
017/00 () |
Field of
Search: |
;324/15-18 ;73/116-119
;33/1N,1PT ;235/92MP ;340/206 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Krawczewicz; Stanley T.
Attorney, Agent or Firm: Dolgorukov; D. Edward
Claims
I claim: .[.1. A device for measuring the timing angle of an
internal combustion engine, said device including means to measure
the time which the engine takes to rotate one full and exact
revolution from top dead center to top dead center, means to
simultaneously measure the time which the engine takes to rotate
from the moment the spark plug in one selected cylinder fires to
the moment the piston in the same cylinder reaches its top dead
center position, means to determine the time the engine takes to
rotate through one degree of the full and exact revolution just
measured, and means to divide the time the engine takes to rotate
from the moment the spark plug fires to the moment the piston
reaches its top dead center position by the time the engine takes
to rotate through one degree, thereby obtaining the timing angle of
the engine..]. .[.2. The device defined in claim 1 and including
means to determine the RPM of the engine on the basis of time the
engine takes to rotate one revolution..]. .[.3. A device for
measuring the timing angle of an internal combustion engine, means
to produce voltage pulsations of uniform time frequency, means to
count said pulsations for at least one full and exact revolution of
the engine, means to simultaneously count pulsations between the
moment the spark plug of a selected cylinder fires and the moment
the piston of said selected cylinder reaches top dead center, means
determining the number of pulsations for one degree of engine
rotation of the revolution for which said pulses were counted and
means to thereupon divide the number of pulsations between moment
of the spark plug firing and the piston reaching its top dead
center position by the number of pulsations the engine took to
rotate one degree, thereby determining the timing angle..]. .[.4. A
device for revealing the timing angle of an internal combustion
engine, said device including an oscillator adapted to produce
electrical pulsations of a uniform time frequency, means to produce
an electrical signal at the moment the piston of a predetermined
cylinder reaches its top dead center position, means responsive to
said electrical signal to begin a first count of said pulsations
from the moment said piston reaches its top dead center position
and continuing said first count for at least one full and exact
revolution of the engine, means to convert said first count into
the time for one degree of engine rotation, means operating during
the time said first count is being taken to produce an electrical
pulse at the moment the spark plug of said predetermined cylinder
fires, means responsive to said electrical pulse to begin a second
counting of pulsations occurring from the moment of said spark plug
firing to the moment the piston next reaches its top dead center
position, means to convert said second count of pulsations into the
time which the engine required to rotate between said spark plug
firing and said top dead center, and means to divide the time which
the engine required to rotate between said spark plug firing and
top dead center by the time for one degree of engine rotation, thus
obtaining the timing angle..]. .[.5. The device as defined in claim
4 and including means to relate said first count of pulsations to
the speed in revolutions per minute of the engine..]. .[.6. The
device defined in claim 5 and including means to compare the timing
angle so obtained with a predetermined range of timing angles..].
.[.7. The device as defined in claim 6 and including a
servo-mechanism responsive to said comparing means and adapted to
adjust the engine distributor to a position to produce a timing
angle within said predetermined range..]. .[.8. A device for
measuring the timing angle of an internal combustion engine, said
device including a frequency divider, an oscillator adapted to
produce, by means of said frequency divider, electrical pulsations
of a uniform time frequency, means to produce an electrical signal
at the moment the piston of a predetermined cylinder reaches its
top dead center position, means responsive to said electrical
signal to begin a first count of said pulsations from the moment
said piston reaches its top dead center position and continuing
said first count for two full and exact revolutions of the engine,
means to convert said first count into the time for one degree of
engine rotation, means operating during the time said first count
is being taken to produce an electrical pulse at the moment the
spark plug of said predetermined cylinder fires, means responsive
to said electrical pulse to begin a second counting of pulsations
occurring from the moment of said spark plug firing to the moment
the piston next reaches its top dead center position, means to
convert said second count of pulsations into the time which the
engine required to rotate between said spark plug firing and said
top dead center, and means to divide the time which the engine
required to rotate between said spark plug firing and top dead
center by the time for one degree of engine rotation, thus
obtaining the timing angle..]. .[.9. The device defined in claim 8,
wherein the means for producing the top dead center signal is in
the form of a magnetic pickup..]. .[.10. The device defined in
claim 8, wherein the means for producing the top dead center signal
is in the form of a photoelectric device..]. .[.11. The device
defined in claim 8, wherein the means to produce a signal when the
spark plug fires is in the form of a coil around the spark plug
wire..]. .[.12. The device defined in claim 8, wherein means to
produce a signal when the spark plug fires is in the form of a wire
loop around the spark plug wire..]. .[.13. The device defined in
claim 8, wherein the means to produce a signal when the spark plug
fires is in the form of a clip placed on the spark plug wire..].
.[.14. The device defined in claim 8, wherein the means to produce
the spark firing signal is in the form of a resistor replacing a
spark plug, and adapted to non-inductively produce a spark plug
firing signal..]. .[.15. The device defined in claim 8, wherein
said signal responsive means include signal conditioners to convert
the electrical pulses into signals compatible with the system, a
control unit connected to said signal conditioners to receive these
signals, a timing binary counter connected to said control unit to
make said second count of pulses and store the result thereof, an
RPM binary counter also connected to said control unit to make said
first count of pulses and store the result thereof, and a
multiplying counter, an arithmetic unit consisting of an adder and
a register connected to said RPM and binary counters and receiving
a signal from said multiplying counter, and a timing binary coded
decimal counter connected to said arithmetic unit, all adapted to
perform the calculation of the timing angle from the information
received from said RPM and said timing binary counter..]. .[.16.
The device defined in claim 15 and including a display unit to give
a visual readout of the timing angle..]. .[.17. The device defined
in claim 16 and including a selector switch connected to said
control unit and adapted to select the number of averages the
timing angle will be calculated over..]. .[.18. The device defined
in claim 17 and including a mode switch connected to the control
unit and adapted to perform an internal test of the system..].
.[.19. The device defined in claim 15 including an RPM binary coded
decimal counter..]. .[.20. The device defined in claim 19 and
including a display unit to give a visual readout of the RPM of the
engine being tested..]. .[.21. The device defined in claim 20 and
including a timing comparator to compare the calculated timing
angle with a predetermined range of timing angles and display the
results of the comparison..]. .[.22. The device defined in claim 21
and including an RPM comparator to compare the calculated RPM with
a predetermined range of RPM and blank out the timing angle display
if the RPM is not within the predetermined range..]. .[.23. The
device defined in claim 22, and including a servo-mechanism
connected to said timing angle comparator and adapted to
adjust the distributor to produce a desired timing angle..]. 24. A
method of measuring the timing angle of an internal combustion
engine having at least one cylinder, a piston, a spark plug, and a
crankshaft connected to said piston; selecting one cylinder as the
base cylinder, running the engine and determining the time required
for one full and exact revolution of the engine from top dead
center to top dead center, simultaneously determining the time
elapsed between the firing of the spark plug in said base cylinder
and the moment the piston in said base cylinder reaches its top
dead center position, determining the time required for one degree
of engine rotation for the revolution of the engine just measured,
and dividing the time elapsed between the spark plug firing and the
moment the piston in said base cylinder reaches its top dead center
position by the time required for one degree of engine rotation,
thereby determining the
timing angle. 25. A method of measuring the timing angle of an
internal combustion engine including at least one cylinder having a
piston, a spark plug, and a crankshaft connected to said piston,
running the engine and producing with the aid of an oscillator
voltage pulsations of a predetermined frequency, counting said
pulsations for one full and exact revolution of the engine from top
dead center to top dead center, simultaneously counting said
pulsations from the moment of spark firing to the moment said
piston reaches its top dead center position in the advanced spark
condition of the engine, determining from the number of pulses just
counted for one full and exact revolution the time required for one
degree of engine rotation during said revolution, and dividing the
time interval between the spark plug firing and the piston reaching
its top dead center position by the time required for one degree of
engine
rotation, thereby determining the timing angle. 26. The method as
defined in claim 24, with the engine running in a retarded
condition, determining the time required for one full and exact
revolution of the engine, simultaneously determining the time
interval between said piston reaching its top dead center position
and said spark plug firing, determining from the number of pulses
just counted for one full and exact revolution the time required
for one degree of engine rotation during said revolution, and
dividing the time between top dead center and the spark plug firing
by the time required for one degree of engine rotation, thereby
determining
the timing angle. 27. The method defined in claim 25, with the time
required for one degree of engine rotation being determined by
producing electrical pulsations of a uniform frequency by means of
an oscillator, counting the pulsations so produced by the
oscillator during one revolution of the engine, relating the number
of pulsations so counted to the time elapsed, and dividing the
elapsed time by 360 to determine said
time for one degree of rotation. 28. The method defined in claim
26, with the time required for one degree of engine rotation being
determined by producing electrical pulsations of a uniform
frequency by means of an oscillator, counting the pulsations so
produced by the oscillator during one revolution of the engine,
relating the number of pulsations so counted to the time elapsed,
and dividing the elapsed time by 360 to determine
said time for one degree of rotation. 29. A method of revealing the
timing angle of an internal combustion engine including a
distributor, a plurality of cylinders each having a piston, a spark
plug, and a crankshaft connected to said piston, selecting one of
the cylinders as a base cylinder, running the engine and producing
with the aid of an oscillator voltage pulsations of a predetermined
frequency, counting said pulsations for one full and exact
revolution of the engine from top dead center to top dead center,
simultaneously counting said pulsations from the moment of spark
firing to the moment said piston reaches its top dead center
position in the advanced spark condition of the engine, determining
from the pulses just counted for one full and exact revolution, the
time required for one degree of engine rotation during said
revolution, and dividing the time between the spark plug firing and
the piston reaching its top dead center position by the time
required for one degree of engine
rotation, thereby determining the timing angle. 30. The method
defined in claim 29, with the engine running in a retarded spark
condition, determining the time required for one full and exact
revolution of the engine, simultaneously determining the time
interval between said piston reaching its top dead center position
and said spark plug firing, determining the time required for one
degree of engine rotation and dividing the time between the piston
reaching top dead center and the spark plug firing by the time
required for one degree of engine rotation,
thereby determining the timing angle. 31. The method defined in
claim 29, with the time required for one degree of engine rotation
being determined by producing electrical pulsations of a fixed
frequency by means of a crystal oscillator, counting the pulsations
so produced by the crystal oscillator during one revolution of the
engine, relating the number of pulsations so counted to the time
elapsed, and dividing the elapsed time
by 360 to determine said time for one degree of rotation. 32. The
method defined in claim 30, with the time required for one degree
of engine rotation being determined by producing electrical
pulsations of a fixed frequency by means of a crystal oscillator,
counting the pulsations so produced by the crystal oscillator
during one revolution of the engine, relating the number of
pulsations so counted to the time elapsed, and dividing the elapsed
time by 360 to determine said time for one degree of rotation.
.Iadd. 33. A device for measuring the timing angle of a selected
cylinder of an internal combustion engine with reference to the top
dead center position of said engine, said device including means to
measure the time which the engine takes to rotate one full and
exact cycle from top dead center to top dead center, means to
simultaneously measure the time which the engine takes to rotate
from the moment the spark plug in one selected cylinder fires to
the top dead center position, means to multiply the time the engine
takes to rotate from the moment said spark plug fires to the top
dead center by the number of degrees in said exact cycle, and means
to divide the value so obtained by said time for one full and exact
cycle, thereby obtaining the timing angle of the engine.
.Iaddend..Iadd. 34. The device defined in claim 33, and including
means to determine the RPM of the engine on the basis of time the
engine takes to rotate one revolution. .Iaddend..Iadd. 35. A device
for measuring the timing angle of a selected cylinder of an
internal combustion engine with reference to the top dead center
position of said engine, said device including means to produce
voltage pulsations of uniform time frequency, means to count said
pulsations for at least one full and exact cycle of the engine,
means to simultaneously count pulsations between the moment the
spark plug of a selected cylinder fires and the top dead center,
means to multiply the number of pulses counted between said spark
plug firing and said piston reaching top dead center position by
the number of degrees in said exact cycle, and means to divide the
value so obtained by the number of pulses counted for said full and
exact cycle, thereby determining the timing angle. .Iaddend. .Iadd.
36. A device for revealing the timing angle of a selected cylinder
of an internal combustion engine with reference to the top dead
center position of said engine, said device including an oscillator
adapted to produce electrical pulsations of a uniform time
frequency, means to produce an electrical signal at the moment the
piston of a predetermined cylinder reaches top dead center
position, means responsive to said electrical signal to begin a
first count of said pulsations from the moment said piston reaches
top dead center position and continuing said first count for at
least one full and exact cycle of the engine, means operating
during the time said first count is being taken to produce an
electrical pulse at the moment the spark plug of said predetermined
cylinder fires, means responsive to said electrical pulse to begin
a second counting of pulsations occurring from the moment of said
spark plug firing to the moment the piston next reaches top dead
center position, means to multiply said second count of pulses by
the number of degrees in said full and exact cycle, and means to
divide the value so obtained by said first count of pulses, thus
obtaining the timing angle. .Iaddend..Iadd. 37. The device as
defined in claim 36, and including means to relate said first count
of pulsations to the speed in revolutions per minute of the engine.
.Iaddend..Iadd. 38. The device defined in claim 37, and including
means to compare the timing angle so obtained with a predetermined
range of timing angles. .Iaddend. .Iadd. 39. The device as defined
in claim 38, and including a servo-mechanism responsive to said
comparing means and adapted to adjust the engine distributor to a
position to produce a timing angle within said predetermined range.
.Iaddend..Iadd. 40. A device for measuring the timing angle of a
selected cylinder of an internal combustion engine with reference
to the top dead center position of said engine, said device
including a frequency divider, an oscillator adapted to produce, by
means of said frequency divider, electrical pulsations of a uniform
time frequency, means to produce an electrical signal at the moment
the piston of a predetermined cylinder reaches top dead center
position, means responsive to said electrical signal to begin a
first count of said pulsations from the moment said piston reaches
top dead center position and continuing said first count for one
full and exact cycle of the engine, means operating during the time
said first count is being taken to produce an electrical pulse at
the moment the spark plug of said predetermined cylinder fires,
means responsive to said electrical pulse to begin a second
counting of pulsations occurring from the moment of said spark plug
firing to the moment the piston next reaches top dead center
position, means to multiply said second count of pulses by the
number of degrees in said full and exact cycle, and means to divide
the value so obtained by said first count of pulses, thus,
obtaining the timing angle. .Iaddend..Iadd. 41. The device defined
in claim 40, wherein the means for producing the top dead center
signal is in the form of a magnetic pickup. .Iaddend. .Iadd. 42.
The device defined in claim 40, wherein the means for producing the
top dead center signal is in the form of a photoelectric device.
.Iaddend..Iadd. 43. The device defined in claim 40, wherein the
means to produce a signal when the spark plug fires is in the form
of a coil around the spark plug wire. .Iaddend..Iadd. 44. The
device defined in claim 40, wherein means to produce a signal when
the spark plug fires is in the form of a wire loop around the spark
plug wire. .Iaddend..Iadd. 45. The device defined in claim 40,
wherein the means to produce a signal when the spark plug fires is
in the form of a clip placed on the spark plug wire.
.Iaddend..Iadd. 46. The device defined in claim 40, wherein the
means to produce the spark firing signal is in the form of a
resistor replacing a spark plug, and adapted to non-inductively
produce a spark plug firing signal. .Iaddend..Iadd. 47. The device
defined in claim 40, wherein said signal responsive means include
signal conditioners to convert the electrical pulses into signals
compatible with the system, a control unit connected to said signal
conditioners to receive these signals, a timing binary counter
connected to said control unit to make said second count of pulses
and store the result thereof, an RPM binary counter also connected
to said control unit to make said first count of pulses and store
the result thereof, and a multiplying counter, an arithmetic unit
consisting of an adder and a register connected to said RPM and
binary counters and receiving a signal from said multiplying
counter, and a timing binary coded decimal counter connected to
said arithmetic unit, all adapted to perform the calculations of
the timing angle from the information received from said RPM and
said timing binary counter. .Iaddend..Iadd. 48. The device defined
in claim 47, and including a display unit to give a visual readout
of the timing angle. .Iaddend..Iadd. 49. The device defined in
claim 48, and including a selector switch connected to said control
unit and adapted to select the number of averages the timing angle
will be calculated over. .Iaddend..Iadd. 50. The device defined in
claim 49, and including a mode switch connected to the control unit
and adapted to perform an internal test of the system.
.Iaddend..Iadd. 51. The device defined in claim 47, and including
an RPM binary coded decimal counter .Iaddend..Iadd. 52. The device
defined in claim 51, and including a display unit to give a visual
readout of the RPM of the engine being tested. .Iaddend..Iadd. 53.
The device defined in claim 52, and including a timing comparator
to compare the calculated timing angle with a predetermined range
of timing angles and display the results of the comparison.
.Iaddend..Iadd. 54. The device defined in claim 53, and including
an RPM comparator to compare the calculated RPM with a
predetermined range of RPM and blank out the timing angle display
if the RPM is not within the predetermined range. .Iaddend..Iadd.
55. The device defined in claim 54, and including a servo-mechanism
connected to said timing angle and said RPM comparator and adapted
to adjust the distributor to produce a desired timing angle.
.Iaddend..Iadd. 56. A method of measuring the timing angle of a
selected cylinder of an internal combustion engine with reference
to the top dead center position of said engine, said engine having
at least one cylinder, a piston, a spark plug, and a crankshaft
connected to said piston, running the engine and determining the
time required for one full and exact revolution of the engine from
top dead center to top dead center, simultaneously determining the
time elapsed between the firing of the spark plug in said cylinder
and the moment the piston in said cylinder reaches top dead center
position, multiplying the time the engine takes to rotate from the
moment the spark plug in said cylinder fires until the piston in
said cylinder reaches top dead center by 360, and dividing the
value so obtained by the time for one full and exact revolution of
the engine, thereby determining the timing angle. .Iaddend..Iadd.
57. The method as defined in claim 56, with the engine running in a
retarded spark condition, determining the time required for one
full and exact revolution of the engine, simultaneously determining
the time interval between said piston reaching top dead center
position and said spark plug firing, multiplying the time the
engine takes to rotate from the moment the spark plug fires until
the piston reaches top dead center by 360, and dividing the value
so obtained by the time for one full and exact revolution of the
engine, thereby determining the timing angle. .Iaddend..Iadd. 58. A
method of measuring the timing angle of a selected cylinder of an
internal combustion engine with reference to the top dead center
position of said engine, said engine including at least one
cylinder having a piston, a spark plug, and a crankshaft connected
to said piston, running the engine and producing, with the aid of
an oscillator, voltage pulsations of a predetermined frequency,
counting said pulsations for one full and exact revolution of the
engine from top dead center to top dead center, simultaneously
counting said pulsations from the moment of spark firing of said
piston to the top dead center position in the advanced spark
condition of the engine, multiplying the number of pulsations
occurring between said spark firing and said top dead center by
360, and dividing the value so obtained by the number of pulses
occurring during one full and exact revolution, thereby determining
the timing angle of said piston. .Iaddend..Iadd. 59. A method of
revealing the timing angle of a selected cylinder of an internal
combustion engine with reference to the top dead center position of
said engine, said engine including a distributor, a plurality of
cylinders each having a piston, a spark plug, and a crankshaft
connected to said piston, running the engine and producing with the
aid of an oscillator voltage pulsations of a predetermined
frequency, counting said pulsations for one full and exact
revolution of the engine from top dead center to top dead center,
simultaneously counting said pulsations from the moment of spark
firing to the top dead center position in the advanced spark
condition of the engine, multiplying the number of pulsations
occurring between said spark firing and said top dead center by
360, and dividing the value so obtained by the number of pulses
occurring during one full and exact revolution, thereby determining
the timing angle. .Iaddend..Iadd. 60. The method defined in claim
59, with the engine running in a retarded spark condition,
determining the time required for one full and exact revolution of
the engine, simultaneously determining the time interval between
said piston reaching its top dead center position and said spark
plug firing, multiplying the number of pulsations occurring between
said spark firing and said top dead center by 360, and dividing the
value so obtained by the number of pulses occurring during one full
and exact revolution, thereby determining the timing angle.
.Iaddend.
Description
This application is a reissue application of U.S. Pat. application,
Ser. No. 200,974, now U.S. Pat. No. 3,763,420, issued Oct. 2, 1973.
.Iaddend.
This invention relates to internal combustion engines, such as
automobile engines, and more particularly to an improved method and
apparatus for measuring and/or adjusting the timing angle of the
engine, i.e., the angle of occurrence of igniting spark in the
cylinder of the engine with respect to the top dead center position
of the pistons of the respective cylinders. In one of its aspects,
the invention relates to providing an improved automatic testing
system, such as a conveyor serving a plurality of test stands, with
each of said stands adapted to receive a test engine and to operate
such engine in a manner to reveal the time of occurrence of the
ignition spark with respect to the top dead center position of the
engine piston, and to set or adjust such time, usually referred to
as "timing angle," at a predetermined or desired point.
A co-pending patent application of Richard L. Smith and Dennis F.
Sauerbrey discloses a method and apparatus for adjusting the timing
angle with the use of encoder producing fast pulsations, such as
3600 pulsations per one revolution of the engine, or 10 pulsations
per degree. The basis of that system is counting, in effect,
degrees. By such count, this system gives timing angle and brings
the desired result.
Such system produces good results and is particularly adaptable to
certain conditions. However, it cannot be economically used under
all conditions. Encoder is a rather expensive device and, in
addition, it is very fragile. It is very sensitive to shocks and
can become unusable after receiving relatively mild shocks.
Furthermore, the encoder has to be connected to the engine in a
test system. It cannot be easily connected to the engine of a
vehicle in such condition as in the parking lot.
One of the objects of the present invention is to devise a method
and apparatus for measuring and/or adjusting the timing angle of
the engine without requiring the use of an encoder.
Another object of the present invention is to provide an improved
test system to measure the timing angle of an internal combustion
engine irrespective of whether or not the engine is in a test stand
or is operating in a motor vehicle or is installed for test in any
other suitable condition.
Another object of the present invention is to provide an improved
engine testing system to have the engine reveal its timing angle,
which system can be conveniently used in repair garages with the
limitations of equipment and personnel present in such garages.
Another object of the invention is to provide an improved test
stand adapted to receive and to operate a test engine to reveal its
timing angle, but without producing actual ignition in the
cylinders thereof, thus eliminating the necessity of operating the
engine on gasoline or on any inflammable gas, such as butane gas,
as well as eliminating the inconveniences and complications
connected therewith.
Another object of the invention is to provide an improved testing
system for automobile engines, said system including a plurality of
test stands receiving test engines from loading stations to have
each engine securely installed in a respective stand for the test,
to run the engine in a manner to reveal correctly its timing angle,
to adjust the distributor automatically to produce a desired timing
angle, to remove the test engine from the respective test stand,
and to deliver the tested engine to the unloading station.
A further object of the invention is to provide an improved engine
test stand adapted to receive and to run the test engine to reveal
its timing angle, all without requiring cooling the engine with
water or removing exhaust gases.
A still further object of the invention is to provide an improved
engine testing system adapted to run the engine to reveal its
timing angle, to release its distributor fixing means, such as
distributor hold down bolt, to adjust the distributor to produce a
predetermined timing angle, and thereupon to retighten said fixing
means.
A still further object of the present invention is to provide an
improved engine testing system of the foregoing character, and
including a spark plug operated by the ignition system of the
engine, as related to a selected cylinder, means to produce
pulsations of uniform time frequency, means to count simultaneously
the number of pulsations so produced for one complete revolution of
the engine and, therefore, also for one degree of engine rotation,
and at the same time count the number of such uniform pulsations
that take place from the moment the spark plug of the selected
cylinder fires until the moment the piston of the selected cylinder
reaches the top dead center. The timing angle .[.is.]. .Iadd.could
.Iaddend.then .Iadd.be .Iaddend.obtained .Iadd.either .Iaddend.by
dividing the time of the last value by the time for one degree of
engine rotation.Iadd., or by multiplying the number of pulses
occurring between spark plug firing and top dead center by the
number of degrees in one complete cycle, and dividing this value by
the number of pulses counted during one complete
cycle.Iaddend..
It is a further object of the invention to provide an improved
timing angle measuring and/or adjusting system in which the uniform
pulsations are produced by a crystal oscillator of known and
uniform time frequency.
It is a further object of the invention to provide an improved
timing angle measuring and/or adjusting system in which the signal
is received from a magnetic pickup activated by the harmonic damper
and is given at the beginning and at the end of one revolution of
the engine at top dead center.
A still further object of the present invention is to provide a
second signal at the moment the spark plug of the selected cylinder
fires.
A still further object of the present invention is to pass the two
signals through a signal conditioner which converts each of the
signals into a low voltage pulse compatible with the system.
A still further object of the present invention is to provide an
improved method and apparatus for measuring and/or adjusting timing
angle of internal combustion engines, in which method and apparatus
there is taken simultaneouslly a count of two values with respect
to the same uniform time pulsations. First, the count of pulsations
per one full and precise revolution of the engine, .[.which gives
also the number of pulsations per one degree of engine rotation;.].
and, second, the number of pulsations from the moment the spark
plug in the selected cylinder fires to the moment when the piston
in the selected cylinder reaches the top dead center (for advance
firing). It can be understood that having received the values for
both of these counts, the timing angle may be easily computed. On
the other hand, if only one system of value is counted, the timing
angle is not obtainable since if number of pulsations in the timing
angle is obtained, there is no way of expressing it with relation
to the degrees of rotation of the engine since the value of the
pulsations in the timing angle not being expressed with relation to
rotation of the engine is meaningless.
A still further object of the present invention is to provide an
improved method and apparatus for measuring and adjusting the
timing angle of an internal combustion engine which also gives the
values for RPM of the engine during the time the measurements are
taken.
A still further object of the present invention is to produce an
improved method and apparatus for measuring and/or adjusting the
timing angle of internal combustion engines, which timing angle
measurement can be used to adjust the distributor and to compare
the obtained results with the high and the low limits of the
established range of such angle.
A still further object of the invention is to provide an improved
method and apparatus for measuring and/or adjusting the timing
angle of the engine, in which there is provided a servo-mechanism
to adjust the distributor.
A still further object of the present invention is to provide an
improved method and apparatus for measuring and/or adjusting the
timing angle of internal combustion engines wherein the necessary
mathematical calculations are performed with the use of binary
mathematics.
It is an added object of the present invention to provide an
improved test system of the above nature which is relatively simple
in construction, dependable in operation, is operated with the
minimum of personnel, and is relatively easy to repair and
service.
Further objects and advantages of this invention will be apparent
from the following description and appended claims, reference being
had to the accompanying drawings forming a part of this
specification, wherein like reference characters designate
corresponding parts in the several views.
FIG. 1 is a perspective view of the control box for operating the
system of the present invention.
FIG. 2 is a side view of the construction of FIG. 1 with one side
panel removed.
FIG. 3 is a plan view of the system as it may be used in a
plurality of test stands connected by a conveyor for measuring
and/or adjusting the timing angle of internal combustion engines in
quantity production.
FIG. 4 is a side view of one test stand with the engine shown in
said stand.
FIG. 5 is a diagram showing one system as it may be used on an
engine outside a test stand.
FIG. 6 is a diagram showing one system with a multiplying counter,
binary timing counter and timing binary coded decimal counter.
FIG. 7 is a diagram showing a complete system with the multiplying
counter, timing binary counter, timing binary coded decimal
counter, RPM binary counter, and a RPM binary coded decimal
counter.
FIG. 8 is a diagrammatic view of the complete system, including the
apparatus necessary to compute the timing angle and RPM of the
engine, to compare the timing angle obtained with a predetermined
range of timing angles, for the predetermined range of RPM and
automatically adjust the distributor to produce a desired value of
timing angle, and further including means to internally test the
system to insure its correct operation.
FIG. 9 is a modification of means for producing the top dead center
signal by using a slot in the harmonic damper.
FIG. 10 is still another modification of means for producing a top
dead center signal by using a hole in the harmonic damper.
FIG. 11 shows another method of picking up a signal when the spark
plug fires by a non-inductive means.
FIG. 12 shows a method of picking up said spark signal without the
use of a spark plug.
FIG. 13 shows an inductive method of picking up a spark signal.
FIG. 14 shows a method whereby the spark signal can be picked up
from the distributor of the internal combustion engine.
It is to be understood that the invention is not limited in its
application to the details of construction and arrangement of parts
illustrated in the accompanying drawings, since the invention is
capable of other embodiments and of being practiced or carried out
in various ways within the scope of the claims. Also, it is to be
understood that the phraseology and terminology employed herein is
for the purpose of description and not of limitation.
The co-pending application of Richard L. Smith and Dennis F.
Sauerbrey discloses a method and apparatus of measuring and
adjusting the timing angle of an internal combustion engine by
measuring, in effect, the degrees of the angle through which the
spark is advanced. With the use of such a method and apparatus,
only one set of values is being measured and after the answer in
terms of such a value, namely the size of the timing angle, is
received, the process is, in effect, completed.
In accordance with my invention, I measure simultaneously two
values. First, I measure the time for one full and precise
revolution of the engine from top dead center of the selected
cylinder to the top dead center thereof. I make such measurements
against uniform pulsations produced with the device capable of
producing pulsations of sufficient frequency, which frequency must
be uniform. While such pulsations are produced, I also measure the
number of pulsations occurring from the moment the spark in the
selected cylinder fires to the moment the piston in the selected
cylinder of the engine reaches the top dead center (for advanced
timing). Measuring both values at the same time, I receive values
which enable me to compute the timing angle of the engine.
.[.It can be easily understood that if I would count only one
value, such as the pulsations from the moment the spark plug of the
selected cylinder fires to the moment the piston in the selected
cylinder reaches top dead center, I would receive only the time
which elapsed between these two moments but would have no way of
expressing this time in terms of the angle, that is timing angle,
since in order to do that I would need to know the time the engine
takes to rotate through one degree. Since I count at the same time
the number of pulsations through one full and exact revolution, I
can compute the number of pulsations per one degree by dividing the
number of pulsations for one revolution by 360..]. Thereupon, I
.Iadd.could .Iaddend.divide the number of pulsations which occurred
between the moment of the spark firing to the moment the piston in
the selected cylinder reaches the top dead center position by the
number of pulsations for one degree. .Iadd.However, I prefer to
multiply the number of pulses occurring between spark firing and
top dead center by 360 and divide the value so obtained by the
number of pulses counted for one full and precise revolution.
.Iaddend.In such a manner I .Iadd.also .Iaddend.obtain the timing
angle expressed in degrees, .Iadd.and do so in a much simpler
manner. .Iaddend.
Since we are concerned primarily with automobile engines which
operate on the principle of four-stroke cycle, the engine makes two
full revolutions during which the spark plug fires once. Therefore,
I prefer to count the number of pulsations for two full and exact
revolutions.Iadd., in which case I would then multiply the number
of pulses occurring from spark firing to top dead center by 720,
and divide the value so obtained by the number of pulses occurring
during two full and precise revolutions.Iaddend..
The above described method of simultaneously counting two values,
namely first the number of pulsations with respect to revolutions
of the engine and thereupon number of pulsations which take place
while the engine rotates through the timing angle, I obtain a
definite answer which could not be received counting only one
value.
Any device producing known and uniform pulsations can be used for
the purposes of the present invention. Since counting of pulsations
is done simultaneously, only one device producing pulsations may be
used, and both values be counted against pulsations produced by
such device.
For the purposes of producing pulsations, I prefer to use a crystal
oscillator since such a device can be selected to produce known and
uniform pulsations of exceedingly high frequency, such as two
million pulsations per second.
In order to define the limits of one revolution or two revolutions,
I use indications of top dead center, which indications can be
produced with magnetic pickup cooperating with such a device as
harmonic damper provided on the engine.
Spark plug firing in one selected cylinder is used, and such spark
plug may be either within the cylinder or outside. The indication
of the piston in the same selected cylinder reaching the top dead
center may be the same as that used to designate the limit of the
revolutions.
In the drawings, there is shown an embodiment of the invention
operating in a manner as required for measuring and/or revealing
the timing angle of one or more automobile engines in production
testing of such engines.
I adapt my system to production requirements in an automobile
plant. The engine may be tested in any suitable condition it is
found in production without any special stands or conveyors, or the
test may be made in one stand, or in a large number of stands
connected by a conveyor into one system adapted to receive the
engines from loading stations and to distribute them to unoccupied
stands of the conveyor for test, and after the test to receive them
from the test stands and direct them to an unloading station.
It should be understood that it is possible to produce and use a
signal other than that of true top dead center as long as the exact
relationship between the signal and true top dead center is known
so that the resulting answer may be corrected by this difference.
Similarly, it is possible to use a signal other than the number one
spark plug as long as the exact relationship between the signal and
the firing of the number one spark plug is known so that the
resulting answer may be corrected by this difference. For example,
the number two spark plug could be used.
It should be further understood that it is possible to produce and
use a signal other than from a pre-selected spark plug, such as
from the coil, or the impulses generated by the distributor.
Referring specifically to FIG. 3, the same shows a test
installation including a plurality of test stands 10 interconnected
with the aid of a conveyor 11, which may be such as those disclosed
in the co-pending applications of V. G. Converse III, et al., Ser.
No. 707,033, filed on Feb. 21, 1968 for Accumulator Conveyor
System, and Ser. No. 717,103, filed on Mar. 29, 1968 for Automated
Engine Test Conveyor, now U.S. Pat. No. 3,527,087. The conveyor 11
is adapted to serve such stands 10 by delivering the test engines,
such as 12, (see FIG. 4) from the loading station 13 to the
respective stands. The test stand which is empty would receive for
test the first passing untested engine, and upon completion of the
test return the tested engine to the conveyor for delivery to the
station 13 for unloading. The tested engine would not be received
by any other stands, even if the stand is empty.
The test performed in each stand depends on the requirements set
therefor, and the engines may be run on gasoline, butane gas, or
may be operated by compressed air or by an electric or fluid (gas
or liquid) motor. Use of compressed air or an electric or fluid
motor insures maintenance of a predetermined speed and does not
require cooling of the engine, although water may be used in the
engine to perform leak tests such as to determine leakage from
water cavity to atmosphere. Oil pressure can also be conveniently
checked in this test by being simultaneously monitored while the
engine is running, with a view of stopping the engine should oil
pressure fail. A visual and audible check for noise can also be
done.
FIG. 4 illustrates one test stand showing a test engine 12 received
by the stand and operatively positioned therein to be driven with
the aid of a motor 14 connected to the engine 12 by the coupling
16. The control box 17 is provided in the stand 10 for the purposes
explained below.
Now turning to the computation of the timing angle, this is
accomplished by measuring the time in seconds between the moment of
firing of the number one spark plug (assuming advanced timing) and
the moment the piston of the selected cylinder reaches top dead
center, and dividing this number by the time in seconds per one
degree of engine revolution. This can be represented by the
mathematical formula: Timing Angle = 720 Y/X, where Y equals time
in seconds between spark plug firing and top dead center and X
equals the time in seconds for two revolutions of the engine.
In order to be able to get values for Y and X, two signals from the
engine are needed, the top dead center (TDC) signal and the spark
firing signal.
Referring to FIG. 4, the TDC (top dead center) signal is produced
as follows: On the front end of the engine 12 there is operatively
mounted a harmonic damper 15 provided on its periphery with a slot
or notch 18 related to the top dead center position of the piston
of number one cylinder. A magnetic pickup 20 is operatively
installed in the stand in such a manner that when the piston of
number one cylinder is at its top dead center position, the notch
18 cooperates with said magnetic pickup 20 in such a manner that an
electrical impulse is produced each time the number one cylinder is
at its top dead center position. This is the TDC signal, the use of
which will be explained below.
Referring to FIG. 5, the distributor 38 supplies high voltage
through the spark plug wire 26 to fire the spark plug 31. The spark
firing signal is produced by a wire loop, coil, or clip 32
surrounding the spark plug wire 26, a current being induced in said
wire loop, coil, or clip 32 each time the high voltage passes
through the spark plug wire 26. This induced current is the spark
firing signal hose purposes will be explained in detail below. It
should be understood that in accordance with the invention, the
spark plug 31 does not need to be mounted in the engine 12 but can
be mounted externally thereto, or the spark firing signal may be
produced without the use of any spark plug.
Referring to FIGS. 6, 7 and 8, the TDC signal obtained in the above
manner from the magnetic pickup 20 is then passed through a signal
conditioner 22 which transforms the input signal into a short
duration pulse (approximately 10 microseconds), which is compatible
with the rest of the system. This signal is then used to turn on
the RPM binary counter 23 to start counting pulsations being
produced by the crystal oscillator 24. The circuit will then
measure the time interval for two complete revolutions of the
harmonic damper 15 which is equivalent of two revolutions of the
engine. This is accomplished by a control unit 27 which turns on
the RPM binary counter 23 when a top dead center signal is sensed.
The counter continues to count pulsations of the frequency produced
from a frequency divider 28 which is driven by the crystal
oscillator 24, until two revolutions of the harmonic damper are
completed, the completion of which is signaled by another top dead
center signal. The result of this count of pulsations is stored in
the RPM binary counter 23 and is proportional to the value of X
above.
Since we are concerned with a four-stroke cycle engine, during the
two revolutions of the engine just measured, the number one spark
plug must have fired once. For an advanced ignition system, the
spark firing signal will occur slightly before top dead center, and
for a retarded ignition system the spark firing signal will occur
slightly after top dead center. The circuit measures the number of
pulsations occurring between the spark plug firing and top dead
center (for advanced timing). This is accomplished by the control
unit 27 which turns on the timing binary counter 30 when the spark
firing signal from the wire loop, coil, or clip 32 is sensed, and
turns the timing binary counter 30 off when the top dead center
signal is sensed. During the interval that the timing binary
counter 30 is turned on, it counts the pulsations of the frequency
produced from the frequency divider 28 which is driven by the
crystal oscillator 24. This count of pulsations is proportional to
the value of Y needed in the above formula.
The actual timing angle computation in this embodiment of the
invention is then performed. The register 29 is cleared, the
contents of the timing binary counter 30 is applied to the input of
the adder 33. This number is added a number of times proportional
to 720 to the contents of the register 29 via the adder 33 and the
resulting new answer is placed in the register 29, the number of
additions being counted by the multiplying counter 34. The
previously stored contents of the RPM binary counter 23 is applied
to the input of the adder 33 in its negated form. This number is
added to the contents of the register 29 via the adder 33 with the
result being placed in the register 29. If the register 29 now
contains a positive non-zero number, one pulse is counted by the
timing binary coded decimal (BCD) counter 35. This process is
repeated as long as the register 29 contains a positive number.
When this process stops, the timing BCD counter 35 then contains
the result of the multiplication of the constant by Y and then the
quantity being divided by X which then equals 720 Y/X, which is the
timing angle. A timing angle display 36 is provided to give a
visual readout of the timing angle so obtained.
If the spark plug fires before top dead center, the positive
indicator light on the timing angle display 36 will show the engine
as running in an advanced spark condition. If the top dead center
signal comes before the spark plug fires, the engine is running in
a retarded condition and the negative indicator light will signal
this condition.
If it is desired to time the engine in a retarded condition, the
time duration between top dead center and spark plug firing is
still a positive number and the calculations are all performed in
exactly the same manner as above.
Now, referring specifically to FIG. 7, this figure shows the same
system as shown in FIG. 6 with the additional apparatus needed to
calculate the RPM.
The RPM of the engine is calculated by dividing 60 (the number of
seconds in a minute) by the time in seconds for one revolution of
the engine. This can be represented by the mathematical equation:
RPM = 120/X, where X represents the time for two revolutions of the
engine.
In the present embodiment of the invention, the actual RPM
calculation using the above formula is done as follows: The
register 29 is cleared and a number proportional to the constant
120 is added to the register 29 via the adder 33, with the
resulting answer being put back in the register 29. The previously
stored contents of the RPM binary counter 23 is applied to the
adder 33 in its negated form. This negated number is added to the
register 29 via the adder 33, with the resulting answer placed in
the register 29. If the register 29 now contains a positive,
non-zero number, one pulse is counted in the RPM binary coded
decimal (BCD) counter. This process is repeated as long as the
register 29 contains a positive number. The RPM BCD counter 39 will
now contain the result of the division of the constant divided by
the contents of the RPM binay counter 23 which is equal to 120/X,
which is the RPM of the engine.
It should be understood that in both of these calculations, the
actual circuitry and numbers used therein have been scaled to
minimize the amount of circuitry and approximately maintain the
same degree of resolution throughout the circuit. Therefore,
numbers that are proportional to the constants in the previously
cited formulas are used rather than the actual numbers.
Referring specifically to FIG. 8, an RPM display 41 is provided to
give a visual readout of the RPM of the engine. Also, the results
of the RPM calculation are applied to the RPM comparator 42 which
compares the contents of the RPM BCD counter 39 to predetermined
lower and upper limits. If the number is not within these limits,
the timing comparator 43 is disabled by the lockout relay 40 and
the timing angle display is blanked out. If the RPM is within
predetermined limits, a timing angle comparator 43 compares the
contents of the timing BCD counter 35 to lower and upper limits and
illuminates one of the appropriate indicator lights 44 to indicate
whether the timing is high, low, or in band, and if needed also
energizes one of the appropriate relays to drive the
servo-mechanism 37 in the appropriate direction to adjust the
distributor 38 to produce a desired value of the timing angle.
One of two relays would be energized. If the timing angle were too
high, the high value relay 45 would be activated and would activate
the servo-mechanism 37 so as to rotate the distributor 38 in the
appropriate direction to lower the timing angle, at which time the
calculation and comparison process would start anew to see whether
the new value of the timing angle is in band. If the timing angle
is too low, the low value relay 46 would be activated in such a
manner as to have the servo-mechanism 37 rotate the distributor in
the opposite direction, thus raising the timing angle, with the
same recalculation and recomparison process again following.
The above process, when complete, has calculated the timing angle
and RPM, compared the RPM with a desired range and if the RPM is in
the desired range, used the value of the timing angle to adjust the
distributor to obtain a desired timing angle.
The servo-mechanism and its control circuitry may be eliminated and
the adjustment done by hand if the system is used manually.
An engine simulation test which can be selected by the mode switch
47 supplies through the frequency divider pulses representing top
dead center and spark to be used in place of the signals coming
from the signal conditioners 22. Under these conditions, specific
numbers should be displayed on the timing angle display 36 and on
the RPM display 41. This provides for an easy internal self test to
check the operation of the unit.
Also, if a more stable result from the system is desired, instead
of performing the timing and RPM calculation over two revolutions
of the engine, it may be performed over a larger number of
revolutions. I prefer to use powers of the number 2 (i.e., 2.sup.z,
where z = 0, 1, 2, . . .) since the system performs its
mathematical computations in the binary system, which is based on
the number 2. A number of averages, such as 4 or 8, can be selected
by the number of averages switch 48.
It should be understood that measuring the number of pulsations
through two full and exact revolutions of the engine may be done
between spark firings, since that equals two revolutions of the
engine.
FIG. 9 shows the damper 50 provided with the slot 51, and having a
bulb 52 providing a light signal to affect a light sensor, such as
a phototransistor 53, to provide a top dead center signal.
FIG. 10 shows another modification of the harmonic damper. The
damper 54 is provided with a hole 55 having an electric light 56 on
one side and a light sensor on the other side.
FIG. 11 shows the spark plug 31 having a metal tube 60 provided on
the top of the spark plug to non-inductively receive the spark
signal and convey it to the signal conditioner 22 through the wire
61.
FIG. 12 shows use of a resistor 62 to take the place of the spark
plug, one side of the resistor 62 being grounded, the signal being
transmitted to the signal conditioner through the wire 63.
FIG. 13 shows a wire loop, clip or coil 32 around the spark plug
wire 26 to inductively produce the spark firing signal when the
spark plug 31 fires.
FIG. 14 shows the distributor points 64 producing the signal to the
signal conditioner 22.
There is thus provided an improved testing system for internal
combustion engines whereby the objects of the present invention
listed above and numerous additional advantages are attained.
* * * * *