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.

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.