Abstract: An apparatus for diagnosing the presence and location of faults within a vehicle's electrical system includes a signal generator for generating an a.c. test signal; a switching circuit connected to an interface between the system's ECU and the system's components for selectively and sequentially applying the a.c. test signal into each electrical lead therein; and a first detector connected to the system's common ground for detecting the system's response to the applied signals, thereby obtaining a set of transitory characteristics for the vehicle's electrical system.

Abstract: The current invention is directed to a method of measuring an electric power and in particular to a precise power measurement by measuring a current and a voltage of high-frequency distortion waves. The current power measuring method is based upon a summation of the power values measured for every frequency component of the distortion wave. After being frequency converted in a mixer 5, a voltage is inputted from an input terminal 1 through a voltage amplifier 3 to a vector voltmeter 7. A current is supplied into an input terminal 2, and converted into a voltage signal by a current-to-voltage converter 4. Then, the voltage signal is frequency-converted in a mixer 6, and thereafter inputted into a vector voltmeter 8. The input signals to the mixers 5 and 6 are separated into frequency components by sweeping of a local signal generator 10, which are measured by the vector voltmeters.

Abstract: An apparatus for identifying the power stroke of a particular cylinder in a multi-cylinder engine which utilizes a wasted spark electronic distributorless ignition system but lacks a camshaft driven cylinder identification sensor, wherein a single sensor can be placed in a coil pack adjacent to and substantially equidistant from the ignition coil towers. The sensor will produce a signal reflecting the difference in voltage drops between corresponding pairs of spark plugs who share the same coil and which utilizes this signal to determine the power stroke of individual cylinders to produce a resulting synthetic cylinder identification signal. This apparatus can further be used as a permanent on-board sensor, thereby negating the need for a separate camshaft driven sensor, to determine the cylinder identification.

Abstract: An engine analyzer for an internal combustion engine converts an engine waveform into a digital waveform which is displayed on a monitor. The waveform is converted using two analog-to-digital (A/D) conversion channels. A dedicated A/D control microprocessor is used to control the flow of the digital waveform data between the analog-to-digital conversion channels and a main computer. Waveform data transfer to the main computer is over a dedicated, high speed data bus. A peripheral control microprocessor is used to monitor other engine parameters and shares memory with the A/D control microprocessor.

Abstract: A digital storage oscilloscope capable of acquiring and displaying input signals over a wide range of frequencies, and automatically establishing, by menu setups or user selection, any of a number of cycles of an input signal for viewing. An input analog electrical signal is sampled at a constant rate and then stored in a fast-acquisition memory. A DSP and a CPU combine to provide an automatic time base which maintains constant width of displayed signals without changing the sampling rate. The time period of one cycle of signal is measured, and the number of digitized samples is reduced or increased by the DSP to provide constant number of samples in order to maintain a constant-width display despite any changes in the input signal frequency. Additionally, the oscilloscope horizontal display axis may be expressed in degrees per division as well as time per division.

Abstract: A linearly moving external part of a multi-cylinder internal combustion engine is contacted with a hand-held contact tachometer for producing a waveform signal which, along with a signal responsive to the ignition of each cylinder, are applied to an engine analyzer processor for display of a single engine cycle of the waveform signal on the CRT oscilloscope of the engine analyzer. The variations and amplitude of the waveform signal correspond to speed variations of the moving part over an engine cycle to give an indication of the relative power contributions of the individual cylinders. Cylinder ignition markers and cylinder zone markers are respectively displayed at the top and bottom of the screen, respectively corresponding to the cylinders in their ignition order. Each cylinder zone marker is delayed a predetermined time from its corresponding cylinder ignition marker and indicates the time period during which the engine responds to the ignition event of the corresponding cylinder.

Abstract: The invention is a method and apparatus for extracting and analyzing features in real time from primary or secondary ignition waveforms, including engine probes, sampling device, and a processor that extracts from the waveform features such as peak firing height, firing line duration, firing line slope, firing line noise, post firing line duration, primary oscillations, and dwell interval duration and compares them against fixed thresholds and running averages to detect anomalies. Anomalies are reported as they occur allowing diagnosis of transient events as well as steady conditions. Waveforms with or without anomalies may be stored and retrieved as needed.

Abstract: Monitoring apparatus is provided for the ignition system of an internal combustion engine such as is provided in a motor vehicle, which is capable of detecting a variety of malfunctions of ignition under a variety of engine operating ranges, so that the catalyst used in the exhaust system of the engine can be protected by setting lambda=0 and/or cutting off fuel injection to an inoperative cylinder, in as many instances of malfunction as possible. Various methods of monitoring are available and are correlated for selection in accordance with the different operating ranges of the engine. The ignition spark duration and the ignition discharge voltage are measured for individual sparks on the primary side of an ignition coil and are compared with limit values for correct ignition, these limit values being selected from a memory in accordance with the particular range of operating conditions in which the engine is operating.

Abstract: Methods and apparatus for detecting low impedance short circuits in a secondary winding circuit of a coil of a distributorless ignition system (DIS) by analyzing spark discharge signals on a primary winding of the ignition coil. In one embodiment, the duration times of the spark discharge signals are compared to a threshold spark duration time, with a low impedance short circuit being indicated if the threshold spark duration time is exceeded. In another embodiment, two or more spark dwell signals are applied to the primary of the ignition coil for each spark event of each associated pair of engine cylinders. A first or base time period is determined for the first dwell signal by measuring the time it takes the first dwell signal to produce a preselected current flow in the primary winding. A second time period is then determined by measuring the time it takes the second dwell signal to produce the same preselected current flow in the primary winding.

Abstract: A digital engine analyzer has an oscilloscope display and is controlled by microprocessors operating under menu-driven stored program control. The analyzer receives analog input signals from an engine being analyzed. The engine calculates and displays real-time cylinder time balance information by calculating for each cylinder the cylinder time period from the firing of that cylinder to the firing of the next cylinder, storing the cylinder time values for each cylinder for a number of successive engine cycles, averaging the time period values for each cylinder over that number of engine cycles, calculating an overall average of the cylinder averages, calculating the percentage difference between each cylinder average and the overall average and then displaying the percentage differences in both numerical and bar graph form along with the overall average value.

Abstract: A digital engine analyzer has an oscilloscope display and is controlled by microprocessors operating under menudriven stored program control. The analyzer receives analog input signals from an engine being analyzed. Peak capture circuitry permits the display of a full cylinder period of a waveform, even though it contains very high frequency portions, by selectively switching between normal and high resolution modes. The circuitry samples the analog waveform at a very high rate and selects samples for display at a much slower display rate. The circuitry captures and stores the highest magnitude sample in each cylinder cycle by storing each sample only if its magnitude exceeds that of the previously stored sample. In the normal mode, at each display clock pulse the most recent sample is selected for display, irrespective of its magnitude. In the high resolution mode the stored peak value is selected for display at each display clock pulse.

Abstract: A digital engine analyzer has an oscilloscope display and is controlled by microprocessors operating under menu-driven stored program control. The analyzer receives analog input signals from an engine being analyzed, digitizes the signals, captures the digital peak ignition voltage values for each cylinder and stores only these values for each cylinder over a number of successive engine cycles, and then simultaneously displays all the stored values for any one cylinder over a number of engine cycles to provide a historical display. Each peak value is stored twice and displayed twice to provide width to the value display and effectively produce a bar graph-type display.

Abstract: A digital engine analyzer has an oscilloscope display and is controlled by microprocessors operating under menu-driven stored program control. The analyzer receives analog input signals from an engine being analyzed. The analyzer is provided with a scanner interface, so that a scanner designed to read data from a vehicle on-board computer, can transfer this data to the analyzer for display on the analyzer oscilloscope. The analyzer processor, when operating in the scanner interface mode, operates under stored program control to reconfigure analyzer keyboard and soft key functions to duplicate scanner control functions, so that the scanner control functions can be effected from the analyzer.

Abstract: A hybrid method and system are disclosed for the detection of internal combustion engine misfires. The method and system are capable of detecting misfires even at very low occurrence rates in real time with inexpensive analog and digital (i.e. hybrid) electronics suitable for use on-board a vehicle, thus satisfying current and proposed exhaust emission control regulations. The method and system exploit a measurement of engine crankshaft angular velocity in conjunction with hybrid electronic signal processing. Once the angular velocity signal is conditioned to minimize the effects of random error and external disturbances, four alternate computationally efficient methods may be used to extract information pertaining to individual cylinder torque productions. Two of the methods employ extremal samples of the estimated torque or velocity waveform to obtain a random torque nonuniformity index or metric.

Abstract: A hybrid method and system are disclosed for the detection of internal combustion engine misfires. The method and system are capable of detecting misfires even at very low occurrence rates in real time with inexpensive analog and digital (i.e. hybrid) electronics suitable for use on-board a vehicle, thus satisfying current and proposed exhaust emission control regulations. The method and system exploit a measurement of engine crankshaft angular velocity in conjunction with hybrid electronic signal processing. Once the angular velocity signal is conditioned to minimize the effects of random error and external disturbances, four alternate computationally efficient methods may be used to extract information pertaining to individual cylinder torque productions. Two of the methods employ extremal samples of the estimated torque or velocity waveform to obtain a random torque nonuniformity index or metric. The other two methods utilize a transformation into the frequency domain.

Abstract: A spark ignition analyzer comprising a probe having a first and second pick-up responsive to a voltage from an ignition wire, a high tension detector for detecting an absolute voltage increase from the first pickup and triggering a first visual signal for a predetermined time period, and a spark detector for detecting a high frequency voltage fluctuation from the second pick-up and triggering a second visual signal for a predetermined time period. The combination of visual signals is used to analyze the ignition system of an engine.

Abstract: Spark discharge signals monitored on primary windings of ignition coils of a coil per plug (CPP) ignition system are used to identify which cylinder of a cylinder pair is in compression and which cylinder in a cylinder pair is in exhaust. Once determined, the cylinder pair can be tracked such that the primary windings do not need to be monitored further. In one embodiment of the invention, the duration times of substantially simultaneous spark discharge signals in cylinders of a pair of cylinders are compared to one another. The shorter duration time signal indicates the cylinder in the compression cycle. One cylinder pair may be tested two or more times or one or more additional cylinder pairs may be tested to verify cylinder identification. In a second embodiment of the invention, two or more spark dwell signals are applied to the primary windings of the ignition coils for each spark event of a pair of cylinders.

Abstract: An engine analyzer for an internal combustion engine includes an analog-to-digital (A/D) converter which digitizes an analog input waveform representing, for example, a secondary or primary voltage waveform of the ignition coil of the internal combustion engine. The sampling rate of the analog digital converter is determined by dividing the waveform time period by the desired number of samples. An adjustment factor C is used to provide a buffer period during the sampling period of the waveform. A display for displaying the waveform has a buffer region which corresponds to the buffer period. Thus, a variation in the speed of the engine which causes the engine to slow down and extends the period of the engine waveform does not cause a loss of data collected from the waveform because the buffer period provides a margin of error.

Abstract: The apparatus for measuring the comparative output power of each cylinder of a multi-cylinder engine comprises a digital signal processor 1 and a phase locked loop detector 2. By inputting instantaneous current measurements from (e.g.) a current transformer attached to an alternator output of an engine under test and analysing same in the processor 1, instantaneous engine speed may be measured. This measurement may be processed to determine comparative measurements of compression and power output of each of the cylinders.

Abstract: A method and apparatus of developing a stabilized power firing event signal for a cylinder in a wasted spark ignition system having pairs of complementarily connected cylinders, each with a spark plug connected to an opposite end of an independent ignition coil. The first and second firing event signals are developed for each spark plug upon firing of the ignition coil. The first and second signals are combined with like polarity in a summation circuit for eliminating common mode signal portions. The combined signal, which is now stabilized and accurately indicates spark duration, is used for capturing secondary ignition data and may be visually displayed for analysis.

Abstract: An inductive pickup assembly senses the electromagnetic fields of plural ignition elements of an automotive engine, access to which elements is prevented by associated engine housing structure. The pickup assembly includes a frame having a flat platform on which multiple sensors are mounted, each sensor comprising an electromagnetic pickup coil with a magnetizable metal core integral with a magnetizable metal shield plate which covers one end of the coil. The frame has a support member with depending feet having apertures which mate with fasteners on the housing structure to serve as a template for accurately locating the pickup assembly on the housing structure.

Abstract: A distributorless ignition interface unit for use with an engine analyzer for analyzing an internal combustion engine includes a processing circuit which responds to analog signals representing true and wasted firings for the cylinders of the engine under test to determine the number of cylinders of the engine and the polarity of the firing of each cylinder and to then characterize the engine by determining the order of the true and wasted firing signals produced during an engine cycle and for producing a parade pattern of true or wasted secondary signals for application to the engine analyzer.

Abstract: A microprocessor controlled digital engine analyzer receives analog input signals from an engine being analyzed, engine parameter data entered via a keyboard, and function data, selecting one of several operating modes for the analyzer and which information is to be displayed, entered via the keyboard, and displays on a CRT screen the selected information such as cylinder firing order, RPM, Dwell, KV and DC volts, alphanumerically, information such as primary and secondary ignition and voltage, alternator and fuel injector information through the use of continuous waveform patterns, and additional information pertaining to Dwell, KV and Cylinder Shorting through the use of bar graphs.

Abstract: An ignition coil primary winding signal processing system that is suitable for use with cathode ray tube based instruments used in the troubleshooting, diagnosing, and servicing of spark ignition internal combustion engines. A primary trigger signal gnerator (4) processes the waveform obtained from the primary winding of the ignition coil of an internal combustion engine, V.sub.S, and produces a logical signal, V.sub.L, which drives a bistable circuit. The bistable circuit includes a D flip-flop FF1 that produces a square wave trigger signal, V.sub.T, whose rising edge corresponds to the point in time of the ignition points break, or the equivalent occurs in an electronic or transistorized ignition system. A dwell angle-to-voltage converter (8) also processes the complex waveform obtained from the ignition coil primary winding of an internal combustion engine, V.sub.S, and produces a nonfluctuating waveform, V.sub.C4, that is compared to a reference voltage.

Abstract: A microprocessor controlled digital engine analyzer receives analog input signals from an engine being analyzed, engine parameter data entered via a keyboard, and function data, selecting one of several operating modes for the analyzer and which information is to be displayed, entered via the keyboard, and displays on a CRT screen the selected information such as cylinder firing order, RPM, Dwell, KV and DC volts, alphanumerically, information such as primary and secondary ignition and voltage, alternator and fuel injector information through the use of continuous waveform patterns, and additional information pertaining to Dwell, KV and Cylinder Shorting through the use of bar graphs.

Abstract: A microprocessor controlled digital engine analyzer receives analog input signals from an engine being analyzed, engine parameter data entered via a keyboard, and function data, selecting one of several operating modes for the analyzer and which information is to be displayed, entered via the keyboard, and displays on a CRT screen the selected information such as cylinder firing order, RPM, Dwell, KV and DC volts, alphanumerically, information such as primary and secondary ignition and voltage, alternator and fuel injector information through the use of continuous waveform patterns, and additional information pertaining to Dwell, KV and Cylinder Shorting through the use of bar graphs.

Abstract: A method of determining the cylinder #1 power firing event in a wasted spark ignition system comprises developing a first signal comprising the integration of all power firing event signals, a second signal comprises the integration of all wasted firing event signals and comparing the amplitudes of the two signals to determine which represents the power firing events. The firing event signals are sorted for integration based upon knowledge of the polarity of spark plug firings, the cylinder firing order and the occurrence of a #1 cylinder firing event signal.

Abstract: An advance reference cylinder trigger generator that provides a more effective trigger signal to synchronize the horizontal sweep of a cathode ray tube based instrument used for troubleshooting, diagnosing and servicing of spark ignition internal combustion engines. The trigger pulses, V.sub.pt, derived from the primary winding of an ignition coil are applied to a cylinder position counter (5) and, after being delayed by a delay circuit (4), to a cylinder count counter (8). When the value of cylinder position counter (5) equals or exceeds the value of cylinder count counter (8), an output from comparator (6) enables a monostable multivibrator (10) to produce an advance reference cylinder trigger V.sub.at upon receipt of the next ignition coil derived trigger pulse, V.sub.pt. Because the V.sub.pt pulses lead spark plug discharge derived pulses, the V.sub.pt pulses lead the spark plug discharge pulse associated with the V.sub.pt pulse causing the firing of the monostable multivibrator.

Abstract: The characteristics of an energizing voltage pulse and of the spark discharge in an ignition device for a gas turbine engine are monitored by providing a voltage whose magnitude and duration correspond to those of an electrical field in the ignition device. An output signal is provided only when the duration and magnitude of the energizing pulse are respectively not greater than and not less than predetermined values, and when the time integral over a preset period of spark discharges in the device is greater than a predetermined value.

Abstract: An adaptor for use in conjunction with an internal combustion engine having a capacitor discharge ignition system provides a substitute high voltage pulse coincident with the high tension pulse of the engine ignition system but having a period which is sufficiently prolonged to enable a conventional engine analyzer to be used to measure the usual engine parameters.

Abstract: An apparatus for generating a synchronizing signal for a selected cylinder of a multi-cylinder engine having a double ended coil ignition system, including a comparator for identifying a real ignition pulse on the ignition device associated with the selected cylinder and a discriminator for identifying a real ignition signal on the coil energizing that ignition device and circuitry to produce a synchronizing signal only when the two coincide.

Abstract: A method or apparatus whereby the primary windings of a multi-coil ignition system may be connected to a common terminal to provide a composite signal identifying the start of each cylinder ignition sequence. Means may also be provided for inhibiting the generation of ignition pulses by selected coils.

Abstract: A method is proposed for self-monitoring of microcomputer-controlled network devices (10) in motor vehicles which in accordance with applied transducer signals execute specified functions and upon detecting an error store a corresponding data word in memory. For indicating the error, the data word is converted into a signal train or voltage and detected by means of voltage measurement. This is preferably accomplished by inserting a diagnosis insert-plug (42) between the transducer lines and the network device (10). A voltmeter (47) can be connected to this test adapter and indicates this signal train or voltage. A specific type of error is associated with a specific voltage. As a result, a diagnosis which is as detailed as desired, of a complicated system, can be performed with a simple voltmeter (47) available in commerce.

Abstract: An engine analyzer for an internal combustion engine includes an analog-to-digital (A/D) converter which digitizes an analog electrical input waveform representing, for example, a secondary or primary voltage waveform of the ignition coil of the internal combustion engine. The digitized input waveform is stored in the form of digital data in a data memory. Upon request by the operator of the apparatus, a microprocessor selects digital data stored, and supplies that digital data to a display, which displays a visual representation of the waveform based upon the selected digital data.

Abstract: An engine analyzer for an internal combustion engine includes an analog-to-digital (A/D) converter which digitizes an analog electrical input waveform representing, for example, a secondary or primary voltage waveform of the ignition coil of the internal combustion engine. The digitized input waveform is stored in the form of digital data in a data mamory. Upon request by the operator of the apparatus, a microprocessor selects digital data stored, and supplies that digital data to a display, which displays a visual representation of the waveform based upon the selected digital data. The engine analyzer apparatus produces a constant width waveform regardless of engine RPM, by determining the period of the waveform to be stored, and then varying the sample rate at which the A/D converter samples the analog waveform and converts the sampled waveform to digital data. As a result, the number of data samples, and thus the width of the displayed waveform, is constant.

Abstract: An engine analyzer, to analyze a parameter of a spark ignition internal combustion engine, has a separate probe for connection to each spark plug or lead feeding only that spark plug, so that engines in which ignition pulses pass to the plugs only along separate leads, can be analyzed.

Abstract: An internal combustion engine analyzer is described which permits analysis to be performed by attaching one sensor to the engine circuit. Timing at idle, engine speed, plug firing parade, etc., can be performed with only one sensor connected to the engine. For more extensive testing wherein additional leads are used, for example, at both the primary and secondary of the engine ignition coil, circuitry is provided for automatically triggering from both primary and secondary input signals or either one if only one is present. The analyzer also contains circuitry that enhances its use with both standard and electronic ignition systems. This circuitry rejects the noise generated by ignition systems in the cylinder ignition signals representative of plug firing so as not to mistrigger, or fire more than once for each plug firing.

Abstract: An engine analyzer, for analyzing ignition voltage or current signals in an engine of the kind in which each spark plug is fed with a succession of pulses, alternate pulses producing real sparks to ignite the petrol/air mixture, the other pulses producing wasted sparks at a point of the engine operating cycle remote from ignition, the analyzer including circuitry to pass the real spark pulse and inhibit passage of the wasted spark pulses.

Abstract: An engine analyzer including a plurality of probes each connectable to one component of a different pair from a plurality of pairs of engine components, each pair comprising a spark plug and a lead connected direct to said spark plug, in which each probe will emit a succession of pulses during use, some or all of the pulses being of either one polarity or of the opposite polarity, wherein the invention comprises means to process said pulses and to emit coincident pulses all of one predetermined polarity, irrespective of the polarity of the pulses from the probe.

Abstract: A testing device is disclosed for testing structural parts and functions of motor vehicles according to a test program having successive program stages. The testing device comprises a program switch for establishing circuit connections associated with the stages of the test program and for controlling a first indicator device for reproduction of the corresponding measurements. The program switch of the device further controls a second indicator device for reproduction of stored, rated measurements associated with the program stages so that a direct comparison of the rated and actual measurements can be quickly made.

Abstract: In order to permit diagnosis of operation and function parameters in a motor vehicle which is equipped with an electronic microprocessor control system without the necessity of providing in the diagnostic equipment substantial additional memory capability, the control system includes a sub-program for diagnosis. A first subprogram executed by the control system in response to a command from the diagnostic equipment gives the appropriate actual operational data to the diagnostic equipment. A second subprogram simulates nominal values for specific vehicle data under various operating conditions and compares these with the actual values. The resulting information is given to an operator by a display and can additionally include various instructions, e.g. repair instructions or a trouble shooting sequence based on the diagnosis.

Abstract: An internal combustion engine analyzer is described which permits analysis to be performed by attaching one sensor to the engine circuit. Timing at idle, engine speed, plug firing parade, etc., can be performed with only one sensor connected to the engine. For more extensive testing wherein additional leads are used, for example, at both the primary and secondary of the engine ignition coil, circuitry is provided for automatically triggering from both primary and secondary input signals or either one if only one is present. The analyzer also contains circuitry that enhances its use with both standard and electronic ignition systems. This circuitry rejects the noise generated by ignition systems in the cylinder ignition signals representative of plug firing so as not to mistrigger, or fire more than once for each plug firing.