Engine ignition and power analyzer

Abstract

An internal combustion engine performance analyzing system is disclosed for displaying a number of operating characteristics, such as engine ignition and cylinder power, which exists under selectively controlled operating conditions. Simple connections to the engine provide the necessary signals to the solid-state electronic analyzer. Various pattern display modes may be selected. An anticipatory cylinder fire signal, which is related to crankshaft rotational degrees, permits a given cylinder to be shorted for the desired interval, regardless of the engine speed. This anticipatory cylinder fire signal is obtained from a servoed ramp waveform generator. Individual cylinder waveform patterns are synchronously and simultaneously displayed on an oscilloscope.

What is claimed is: 1. In an apparatus for analyzing the operation of a multiple cylinder internal combustion engine having an ignition time interval for each cylinder during which ignition normally occurs, the combination which comprises: 
     
        corresponds to the firing time of the first cylinder. 5. The combination as defined in claim 4 wherein the means for providing the second control pulse comprises: a first servo sweep generator for generating a sawtooth voltage in response to the occurrence of the first control signal, which sawtooth voltage has an amplitude independent of the repetition rate of the ignition pulses; and   a first amplitude level detector connected to the first servo sweep generator and responsive to a preset amplitude level of said sawtooth voltage to generate said second control pulse. 6. The combination as defined in claim 5 including:   a second amplitude level detector connected to the servo sweep generator and responsive to a preselected amplitude level of said sawtooth signal to generate a strobe pulse,   means connected to the second level amplitude detector for varying said preselected amplitude level, and   a strobe lamp responsive to the strobe and third control pulses for producing a flash of light which may be used to monitor the ignition advance of the engine. 7. The combination as defined in claim 5 wherein the means for generating the first control pulse includes probe pickup means for generating electrical signals representative of the ignition characteristics of individual cylinders and further including:   a second servo sweep generator having an input and an output, the sweep generator being arranged to generate a sawtooth sweep signal of constant peak amplitude in the output in response to the application of an input pulse to the input thereof,   means for selectively coupling the second control pulse to the input of the second servo sweep generator to initiate the sweep signal,   a cathode ray oscilloscope having horizontal and vertical inputs,   means connecting the horizontal input of the oscilloscope to the output of the second servo sweep generator, and   means connecting the probe pickup means to the vertical input of the oscilloscope. 8. The combination as defined in claim 7 wherein the means for generating the ignition suppression signals includes a multistage ring pulse counter having operative stages equal to the number of cylinders in said engine and reset means responsive to said third control pulse to place all of the said stages of said pulse counter in a reset condition, each stage of the ring counter being arranged to produce an ignition suppression signal for a respective cylinder. 9. The combination as defined in claim 8 wherein the internal combustion engine is provided with an ignition coil having a primary and a secondary winding and wherein the means for suppressing the ignition in a selected cylinder includes a shorting switch connected across the primary winding of the ignition coil for shorting said winding in response to an ignition suppression signal and gating means connected between the ring counter and the shorting switch for supplying the ignition suppression signals from a selected stage of the ring counter to the shorting switch. 10. The combination as defined in claim 9 wherein the gating means includes a remotely located cylinder selector switch connected to the ring counter and the shorting switch, the cylinder selector switch having a switch position individually associated with each cylinder of the engine. 11. The combination as defined in claim 10 wherein the means for selectively coupling the second control pulse to the input circuit of the second servo sweep generator includes a remotely located pattern select switch for selectively coupling each second control pulse or only each second control pulse which coincides with the third control pulse to the input circuit of the second servo sweep generator whereby the ignition signals may be displayed in a superimposed or a horizontally spaced pattern on the oscilloscope screen. 12. The combination as defined in claim 9 wherein the gating means includes an AND gate individually connected between each stage of the ring counter and the shorting switch and a multi-position cylinder selector switch having a number of positions at least equal to the number of cylinders of the engine and coupled to the AND gates, the selector switch being arranged so that each position thereof enables a selected AND gate to pass ignition suppression signals through said AND gate to the shorting switch. 13. The combination as defined in claim 7 wherein the means for selectively coupling the second control pulse to the input circuit of the second servo sweep generator includes a raster gate, a parade gate and a pattern select switch for selectively enabling one of said gates, and means for coupling the third control pulse to the parade gate, the raster gate being arranged to pass the second control pulse to the second servo sweep generator when enabled by the pattern select switch, the parade gate being arranged to pass the second control pulse to the second servo sweep generator only on the occurrence of the third control pulse when enabled by the pattern select switch. 14. The combination as defined in claim 13 wherein the oscilloscope includes beam brightening means for increasing the intensity of the writing beam and further including means responsive to the pattern select switch and to the first control pulse for applying a pulse to the beam brightening means of the oscilloscope to increase the intensity of the writing beam on each occurrence of the first control pulse when the raster gate is enabled. 15. The combination as defined in claim 13 including a point open gate connected to the input circuit of the second servo sweep generator and the pattern select switch for selectively coupling the first control pulse to the input circuit of the second servo sweep generator to initiate the servo sweep signal. 16. The combination as defined in claim 8 including means for selectively varying the number of stages in the ring counter to accommodate engines with different numbers of cylinders. 17. The combination as defined in claim 16 including:   a summing network connected to the stages of the ring counter for generating staircase voltage therefrom, the number of steps of the staircase voltage being equal to the number of stages in the ring counter, and   means connecting said summing network to the vertical input of said oscilloscope whereby the displayed waveforms representing individual cylinders may be vertically spaced on the oscilloscope screen. 18. The combination as defined in claim 17 wherein the means connecting the summing network to the oscilloscope includes means for selectively varying the amplitude of the staircase voltage in accordance with the number of cylinders in the engine under test to permit the entire oscilloscope screen to be utilized for displaying the ignition characteristics of engines having different numbers of cylinders. 19. The combination as defined in claim 17 wherein the means connecting the summing network to the oscilloscope includes means for selectively varying the amplitude of the staircase voltage in accordance with the number of cylinders in the engine under test to permit the entire oscilloscope screen to be utilized for displaying the ignition characteristics of engines having different numbers of cylinders. 20. The combination as defined in claim 3 including means for selectively varying the number of stages in the ring counter to accommodate engines with different numbers of cylinders. 21. The combination as defined in claim 20 including:   a summing network connected to the stages of the ring counter for generating a staircase voltage therefrom, the number of steps of the staircase voltage being equal to the number of stages in the ring counter, and   means connecting said summing network to the vertical input of said oscilloscope whereby the displayed waveforms representing individual cylinders may be vertically spaced on the oscilloscope screen. 22. The combination as defined in claim 1 including means responsive to the first control pulse for providing an indication of engine r.p.m., whereby the power contribution of individual cylinders can be ascertained when the   
     
     
        ignition in each of the cylinders is suppressed. 23. In an apparatus for analyzing the operation of the multiple cylinder combustion engine provided with an ignition coil having a primary and secondary winding for supplying electrical ignition pulses to the cylinders, the combination with comprises: probe pickup means coupled to the ignition coil for generating electrical signals representative of the ignition characteristics of individual cylinders,   pulse shaping means coupled to the probe pickup means for generating a first control pulse in response to the ignition pulse for each of the cylinders,   means responsive to each occurrence of the first control pulse for providing a second control pulse which is delayed from the occurrence of the first control pulse by an amount directly proportional to the interval between the successive times of the cylinder ignition,   a cathode ray oscilloscope having vertical and horizontal inputs,   means coupled to the horizontal input of the oscilloscope and responsive to the occurrence of the second control pulse for applying a sawtooth sweep signal of constant peak amplitude in advance of each cylinder ignition to said horizontal input, .[..[.and.]..].   means for coupling the probe pickup means to the vertical input of the oscilloscope.Badd.,   means responsive to the occurrence of the second control pulse for generating an anticipatory ignition suppression signal in advance of the ignition time in each cylinder, and   means coupled to the ignition coil and responsive to the ignition suppression signal for suppressing the ignition in a selected   
     
     
        cylinder.Baddend.. 24. The combination as defined in claim 23 wherein the means for providing the second control pulse comprises a first servo sweep generator for generating a sawtooth voltage waveform of constant peak amplitude in response to the occurrence of the first control pulse and a first amplitude level detector connected to the first servo sweep generator and responsive to a preset amplitude level of the sawtooth 
     
     
        waveform to generate the second control pulse. .[..[.25. The combination as defined in claim 24 including means responsive to the occurrence of the second control pulse for generating an anticipatory ignition suppression signal in advance of the ignition time in each cylinder and means coupled to the ignition coil and responsive to the ignition suppression signal for suppressing the ignition in a selected cylinder..]..]. 26. The combination as defined in claim .[..[.25.]..]. .Badd.23 .Baddend.wherein the means for generating the ignition suppression signal includes: a multi-stage ring pulse counter having stages equal to the number of cylinders in said engine and further including:   means connected to the first cylinder of said engine for producing a third control pulse in response to the ignition in said first cylinder,   preset means responsive to a third control pulse to place all of the stages of the pulse counter in a preset condition, and   means for incrementally advancing the count on said ring pulse counter with   
     
     
        the occurrence of each of the second control pulses. 27. The combination as defined in claim 26 wherein the means for applying the sawtooth sweep signal to the horizontal input of the oscilloscope comprises: a second servo sweep generator having an input and an output connected to the horizontal input of the oscilloscope, the second servo sweep generator being arranged to generate the sawtooth sweep signal in response to the application of each second control pulse to the input thereof; and   means for selectively applying the second control pulse to the input of the second servo sweep generator upon each occurrence thereof or upon the occurrence of the second control pulse and the third control pulse. 28. The combination as defined in claim 24 wherein the probe pickup means includes a primary pickup probe connected to the primary winding of the ignition coil and a secondary pickup probe connected to the secondary winding of the ignition coil and wherein the pulse shaping means includes gating means for selectively generating the first control pulse in response to electrical signals generated in either the primary or secondary pickup probe. 29. The combination as defined in claim 23 wherein the pulse shaping means includes an input terminal, an output terminal and a ground and a pair of gates connected between the input and output terminals thereof for providing the first control pulse of one polarity between the output terminal and ground in response to the application of a positive or negative input pulse between the input terminal and ground. 30. The combination as defined in claim 23 including:   a multistage ring counter having a stage individually associated with each cylinder,   means coupled to the engine and responsive to the ignition of the first cylinder thereof for resetting the stages of the ring counter,   means for advancing the count in the ring counter in response to the occurrence of each second control pulse,   means for selectively varying the number of stages in the ring counter to accommodate engines with different numbers of cylinders,   a summing network connected to the stages of the ring counter for generating a staircase voltage therefrom, the number of steps of the staircase voltage being equal to the number of stages in the ring counter,   means connecting the summing network to the vertical input of the oscilloscope, and   means for selectively varying the amplitude of the staircase voltage in accordance with the number of cylinders in the engine under test to permit the entire oscilloscope screen to be utilized for displaying ignition   
     
     
        characteristics of engines having different numbers of cylinders. 31. Apparatus for analyzing the functioning of a multiple-cylinder internal combustion engine having an ignition coil, comprising: means for picking up ignition pulses from said ignition coil;   pulse shaping means connected to said ignition pulse pickup means for producing a first control pulse therefrom upon each occurrence of an ignition pulse;   means responsive to the first control pulse for providing a second control pulse which is delayed from the occurrence of the first control pulse by an amount which is directly proportional to the interval between successive ones of the ignition pulses;   means connected to the first cylinder of said multiple-cylinder engine for producing a third control pulse whenever the first cylinder fires;   a multistage ring pulse counter having stages equal in number to the number of cylinders in said engine;   reset means responsive to the third control pulse to place all of the stages of the pulse counter in a reset condition;   means for incrementally advancing the counter in the ring pulse counter with the occurrence of each of the second control pulses; and   utilization means connected to the output of the stages of the ring pulse counter and responsive to the pulse count therein.Badd., and connected to the ignition coil for repressing the ignition of a selected one of the cylinders of the engine in accordance with a given count in the ring pulse   
     
     
        counter.Baddend.. 32. The combination as defined in claim 31 wherein the means for providing the second control pulse comprises: means for generating a sawtooth waveform in response to the occurrence of the first control pulse, which sawtooth waveform has an amplitude independent of the repetition rate of the ignition pulses; and   an amplitude level detector connected to the output of the sawtooth waveform generating means and responsive to a preset amplitude level of said waveform to generate the second control pulse. 33. The combination as defined in claim 32 including:   a cathode ray oscilloscope having horizontal and vertical inputs,   means responsive to the second control pulse for generating a sawtooth sweep signal,   means for coupling the sawtooth sweep signal to the horizontal input of the oscilloscope, and   means connecting the means for picking up the ignition pulses to the vertical input of the oscilloscope. 34. The combination as defined in claim 33 including:   a current summing network connected to the stages of the ring pulse counter for generating a staircase waveform therefrom; and   means connecting the network to the vertical input of the oscilloscope whereby the displayed waveforms may be vertically separated. 35. The combination as defined in claim 34 including:   pattern select switch means interposed between the second control pulse providing means, the third control pulse producing means and the sweep signal generating means for synchronizing the sweep signal with the occurrence of each second control pulse or the occurrence of each second   
     
     
        and third control pulses. .[..[.36. The combination as defined in claim 35 wherein the utilization means includes means connected to the ring pulse counter and to the ignition coil for repressing the ignition of a selected one of the cylinders of the engine in accordance with a given count in the 
     
     
        ring pulse counter..]..]. 37. The combination as defined in claim 31 including: a strobe lamp connected to the second control pulse providing means and to the third control pulse producing means, and responsive to the simultaneous occurrence of said second and third control pulses to generate a visible flash of light which may be used to monitor the ignition advance setting of said engine. 38. The combination as defined in claim 31 wherein the pulse shaping means includes an input terminal, an output terminal and a ground and a pair of gates connected between the input and output terminals thereof for providing the first control pulse of one polarity between the output terminal and ground in response to the application of a positive or negative input pulse between the input terminal and ground. 39. In an apparatus for analyzing the operation of a multiple cylinder internal combustion engine having an ignition time interval for each cylinder during which ignition normally occurs, the combination which comprises:   means coupled to the engine for generating a first control pulse in response to the ignition time interval for each of the cylinders, the first control pulse having a short time duration which is independent of the rotational velocity of the engine,   means responsive to each first control pulse for providing a second control pulse which is delayed from the .[..[.presense.]..]. .Badd.presence .Baddend.of the first control pulse by an amount which is directly proportional to the interval between the successive times of cylinder ignition,   means responsive to each occurrence of the second control pulse for generating anticipatory ignition suppression signals in advance of the ignition times in respective cylinders, and   means coupled to the engine and responsive to the ignition suppression signals for suppressing the ignition in a selected cylinder. 40. The combination as defined in claim 39 wherein the means for providing the second control pulse includes a sweep generator for generating a ramp voltage in response to each first control pulse. 41. The combination as defined in claim 40 wherein the means for providing the second control pulse further includes means for generating a reference signal and means for comparing the ramp voltage with the reference signal. 42. The combination as defined in claim 41 wherein the means for providing the second control pulse further includes servo control means for adjusting one of the ramp voltage and the reference signal in response to the time period between the preceding cylinder ignitions. 43. The combination as defined in claim 39 wherein the means for providing the second control pulse includes means for adjusting the amount of the time delay between   
     
     
        the first and second control pulses. 44.  Apparatus for analyzing the functioning of a multiple-cylinder internal combustion engine having an ignition coil, comprising: means for picking up ignition pulses from said ignition coil:   pulse shaping means connected to said ignition pulse pickup means for producing a first control pulse therefrom upon each occurrence of an ignition pulse, the 1st control pulse having a short time duration which is independent of the frequency of the ignition pulse;   means responsive to the first control pulse for providing a second control pulse which is delayed from the occurrence of the first control pulse by an amount which is directly proportional to the interval between successive ones of the ignition pulses;   means connected to the first cylinder of said multiple-cylinder engine for producing a third control pulse whenever the first cylinder fires;   a multistage ring pulse counter having stages equal in number to the number of cylinders in said engine;   reset means responsive to the third control pulse to place all of the stages of the pulse counter in a reset condition;   means for incrementally advancing the counter in the ring pulse counter with the occurrence of each of the second control pulses; and   utilization means connected to the output of the stages of the ring pulse counter and responsive to the pulse count therein.Badd., and connected to the ignition coil for repressing the ignition of a selected one of the cylinders of the engine in accordance with a given count in the ring pulse   
     
     
        counter.Baddend.. 45.  The combination as defined in claim 44 wherein the means for providing the second control pulse is a servo controlled timing circuit which is responsive to the time delay between preceeding ignition pulses for causing the second control pulse to occur a predetermined number of degrees of engine rotation in advance of the next ignition pulse. 46. In an apparatus for analyzing the operation of a multiple cylinder internal combustion engine having an ignition time interval for each cylinder during which ignition normally occurs and an ignition system for generating an ignition pulse to initiate the ignition in each cylinder, the combination which comprises: means adapted to be coupled to the engine ignition system for generating a first control pulse in response to each ignition pulse, the first control pulse having a short time duration which is independent of the rotational velocity of the engine,   a timing circuit responsive to each first control pulse for producing a second control pulse which is delayed in time from the completion of each first control pulse by an amount which is inversely proportional to the frequency of the ignition pulses,   means responsive to the second control pulses from the timing circuit for generating anticipatory ignition suppression signals in advance of the ignition times in respective cylinders, and   means coupled to the engine and responsive to the ignition suppression signals for suppressing the ignition in a selected cylinder. 47. The combination as defined in claim 46 wherein the timing circuit includes means for generating a ramp voltage, means for providing a reference signal and means for comparing the instantaneous amplitude of the ramp voltage and reference signals to provide the second control pulse when said instantaneous amplitudes are equal. 48. The combination as defined in claim 47 wherein the reference signal is fixed in amplitude during the engine operation.