Abstract: A power tool that includes a brushless DC motor, one or more motor sensors, and a controller, such as, for example, an electronic speed control (ESC) circuit. The controller is adapted to provide instructions to control the operation of one or more parameters of the brushless DC motor. The controller is also adapted to receive feedback from one or more motor sensors that reflect whether the motor is attaining the one or more parameters. The controller may also be adapted to have a learning mode, in which feedback provided during use of the power tool is stored by the controller as a program so that the same operating parameters may be subsequently replicated by using the program to operate the tool. The controller may also use the feedback to adjust the operation of the motor so that the motor maintains one or more selected or programmed operating parameters.

Abstract: A device for ascertaining a suitable position of a sensor device for detecting a measured variable includes: a detection device for detecting environmental data in a surrounding area of the sensor device; a computing unit for ascertaining the suitable position of the sensor device based on the detected environmental data and the measured variable; and an output device for displaying the ascertained suitable position of the sensor device.

Abstract: An inductive power transfer (IPT) pick-up circuit for receiving power from a primary conductor has a pick-up coil (L2) and a compensation capacitor (C2) so that the pick-up coil (L2) may be resonant at the system operating frequency a switch (S1, S2), and a plurality of reactive elements (L3, C3) whereby when the switch is in one of an on state or an off state the additional reactive elements (L3, C3) are resonant at the operating frequency to reduce power being supplied to an output of the pick-up circuit.

Abstract: A power transmission pad is configured to provide wireless power transmission to multiple portable electronic devices where each device is orientation-free relative to the pad. The power transmission pad is also configured to be power adaptive by changing the power transmission level depending on the number of devices being concurrently charged. Each device, is placed within the magnetic field for the purpose of charging the device battery. The power transmission pad includes a sweep frequency generator for generating power transmissions across a frequency spectrum. The number of devices to be charged is determined as well as an optimal frequency for maximum energy transfer to each device. A single combined optimal frequency is determined using the optimal frequencies determined for each individual device. The sweep frequency generator is locked to the single combined optimal frequency and a power transmission level is set according to the number of devices.

Abstract: A system for a vehicle, includes a rockback detection module and a starter disabling module. The rockback detection module receives a crankshaft position signal from a bi-directional crankshaft sensor and selectively indicates that a crankshaft of an engine is rotating in a first direction based on the crankshaft position signal. The engine rotates in a second direction that is opposite to the first direction when the engine is running. The starter disabling module disables current to a starter motor when the crankshaft is rotating in the first direction.

Abstract: A method for generating a simulated sensor signal pattern for a marking gap of a signal-generating disk which is coupled with a crankshaft of an internal combustion engine, the signal-generating disk having a marking by the alternating positioning of teeth and tooth interstices, and the marking gap being formed by an enlarged tooth interstice or an enlarged tooth, and at least one sensor being assigned to the signal-generating disk, the sensor in each case being able to generate an electrical signal that is able to assume at least two signal levels (high, low), one of the signal levels (high, low) being assigned to a tooth and the other to a tooth interstice, and a simulated sensor signal pattern being approximated for the marking gap from the signal pattern of the signal generated by the sensor, wherein the signal pattern lying before the marking gap in time is used for the approximation.

Abstract: An apparatus comprises an edge detector, a memory and a pulse-input engine. The edge detector is configured to receive an input signal and a counter signal. The edge detector is further configured to send a set of time values based on the input signal and the counter signal. Each time value from the set of time values is uniquely associated with a detected edge transition from the input signal. The memory is coupled to the edge detector. The memory is configured to receive from the edge detector the set of time values. The memory is configured to store the set of time values. The pulse-input engine is coupled to the memory. The pulse-input engine is configured to measure a set of pulse-to-pulse delays based on the set of the time values stored in the memory.

Abstract: A digital ignition system tachometer driver connected to an ignition coil of the ignition of an automobile for converting the ignition coil signal from one or more ignition coils to a single tachometer output signal. The digital ignition system tachometer driver includes a current mirror for mirroring the coil current, a voltage comparator for comparing the mirrored current to a reference voltage, and a mode detector for determining whether the coils are operating in a multispark mode. A reverse-polarity and over-voltage protection circuit is provided to protect the current mirror. An input current and voltage limiting circuit is provided for protecting the tachometer driver circuit.

Abstract: A measurement system and method for determining a revolution rate of a rotating gear is described. Such a rotating gear can be, for example, a turbine or compressor. The described measurement system and method, for example, can perform highly accurate measurements and can be a fault tolerant system providing high reliability. In one embodiment, an apparatus comprises an edge detector, a memory and a pulse-input engine. The edge detector is configured to receive an input signal and a counter signal. The edge detector is further configured to send a set of time values based on the input signal and the counter signal. The pulse-input engine is configured to measure a set of pulse-to-pulse delays based on the set of time values stored in the memory.

Abstract: In an engine ignition unit, a transistor and a current detecting resistor are connected to primary and secondary windings of an ignition coil, respectively. The current detecting resistor is used for detecting a current flowing between the opposing electrodes of spark plug. At an ignition by the spark plug, high-frequency square wave signals are generated by an oscillator after an ignition signal is cut off. The square wave signals turn on and off the transistor. By this operation, a battery voltage is intermittently applied to the primary winding and an ion current is measured. A frequency of the square wave signals is set close to a resonant frequency of an ion current path including the spark plug, the secondary winding of the ignition coil and the current detecting resistor.

Abstract: An apparatus for determining component fault conditions associated with a capacitive discharge ignition system for an internal combustion engine includes a number of AC coupling circuits connected to a spark detection circuit, wherein the combination is responsive to a corresponding number of primary coil voltage signals to produce digital pulses indicative of reflected spark events from the various secondary coils to the respective primary coils of the ignition system. A number of level shifting circuits are also included and provide a pulse width circuit with a corresponding number of level-shifted primary coil voltage signals. A pulse width circuit is responsive to the number of level-shifted primary coil voltage signals to produce appropriate digital pulses timed to match the non-zero voltage times of the various primary coil voltage signals.

Abstract: A cylinder identifying apparatus comprising a crank angle sensor 20 detecting a crank angle of a combustion engine 14 having a plurality of cylinders, a cylinder identifying means 31 identifying a cylinder to be controlled by an output signal from the crank angle sensor 20, a cranking judging means 34 detecting a cranking state of the combustion engine 14, and an erroneous cylinder identification preventing means 32 detecting starting of cranking of the combustion engine 14 by an output from the cranking judging means, and circumventing the cylinder identification by the cylinder identifying means 31 until a predetermined time passes after starting the cranking, whereby the cylinder to be controlled is securely identified at time of cranking, and erroneous detection, erroneous control, and detection delay are prevented.

Abstract: A digital degree wheel is provided including an engine sensor mounted to at least one of a camshaft, distributor and crankshaft of a vehicle for generating an activation signal after the detection of the rotation thereof. An ignition sensor connected to an ignition of the vehicle for generating a deactivation signal upon the detection of the advancing of the ignition of the vehicle. A display connected to the ignition sensor and the engine sensor for displaying a plurality of numeric digits representative of a timer, which is adapted to begin upon the receipt of the activation signal and further cease upon the receipt of the deactivation signal for setting and checking the ignition and valve timing of an engine of the vehicle.

Abstract: An apparatus for detecting a condition of burning in an internal combustion engine includes a pair of opposed electrodes provided in a combustion chamber of the engine, and an AC voltage applying device for applying an AC voltage between the opposed electrodes. A current detecting device is operative for detecting a current flowing between the opposed electrodes. A current generating means for generating a current-representing signal depending on the detected current, the current generating means having a differentiating circuit for differentiating the AC voltage into the capacitance-current representing signal. In another aspect of this invention, the apparatus further comprises calculating means for calculating ratios between a parameter represented by the burning-ion current representing signal and a parameter represented by a signal depending on the AC voltage applied between the opposed electrodes.

Abstract: A ground pick-up tachometer for detecting a rotational speed of an engine in a vehicle includes a probe arranged for connection to a vehicular ground to detect signals emitted from an ignition system of the engine. A tachometer circuit is operatively connected to the probe to identify the detected signals representing ignition sparks and provide an output representative of the rotational speed of the engine based on the identified signals. The tachometer circuit includes a circuit common reference, separate from the vehicular ground.

Abstract: A timing light for adjusting an engine's timing has a stroboscopic lamp for illuminating the timing marks and a trigger circuit for causing the stroboscopic lamp to illuminate the timing marks at a desired time. The trigger circuit has an input circuit receiving a signal representative of a spark plug firing; an output circuit providing a trigger signal to the stroboscopic lamp to cause the stroboscopic lamp to flash; and an anticipation circuit configured to determine when to provide the trigger signal to the stroboscopic lamp by establishing a trend in the rate of which the spark plug is firing so as to predict when a next trigger signal is to be provided by the output circuit. Establishment of the trend in the rate of which the spark plug is firing generally enhances the accuracy with which the engine's timing is measured.

Abstract: An engine monitor includes, in a self-contained preferably sealed unit, a spark sensor, inductively and capacitively coupled through the case to a spark pick up wire, a timer, and a running time detector, responsive to inputs from the spark pick up to provide total running time, job time, and service time metering. Preferably, storage means are included for storing maximum RPM and spark mode data, that is, data indicating the number of firings per RPM for the particular engine, as well as a preset service interval and one or more auxiliary timers.

Abstract: A misfire detector for an internal combustion engine is provided which, if any of a plurality of modification factors is replaced by a value out of the proper range, can prevent erroneous misfire detection from, continuing.

Abstract: An inductive pickup sensor employing an isolation transformer to achieve substantially improved immunity to capacitively-induced cross-talk signals is provided. A magnetic pickup coil is coupled to a spark plug wire to receive a spark signal. The spark signal developed across the magnetic pickup coil is then coupled to via a sensor cable to the primary winding of an isolation transformer which is configured to provide a relatively low interwinding capacitance level to substantially reduce the cross-talk signal amplitude relative to the spark signal at a detector circuit. The detector turns the spark signal into a trigger signal at a pair of output terminals.

Abstract: A diesel timing light includes a flash circuit for flashing a xenon lamp in response to ignition events sensed by a knock sensor. A trigger circuit enables the flash circuit only in the presence of an enable signal, which is generated by a sensing circuit immediately before the ignition of the no. 1 cylinder. The sensing circuit includes a visible laser source which illuminates a patch of reflective tape on the engine flywheel just ahead of a timing mark corresponding to engine top dead center. The tape reflects the visible laser light to a sensor which generates the enable signal. The trigger disables the flash circuit immediately after the flash triggered by the first ignition event after the enable signal. LED indicators indicate when the photosensor is detecting the reflected beam and when the knock sensor is detecting ignition events.

Abstract: A contactless inductive power distribution system operating at 10 KHz has a self tuning resonant power supply connected to a resonant primary conductive path comprising a pair of parallel litz wire conductors each encapsulated within an insulated sheath and supported on a structural monorail beam on which a plurality of electric vehicles can run. Each vehicle has an electric motor capable of deriving power from a resonant pick-up coil wound on a ferrite core mounted on the vehicle in close proximity to the primary conductors. Each vehicle also has switching means capable of preventing a lightly loaded vehicle from presenting a reduced load to the resonant primary. In one version this comprises an isolating coil having a switch to switch the coil between an open circuit and a short circuit, so that when the switch is switched from one state to another state the power coupled between the primary conductive path and the pick-up coil is changed.

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: An ignition apparatus for an internal combustion engine is provided in which malfunctions due to noise induced by a high ignition voltage can be avoided in a reliable manner. A controller controls the ignition timing of a cylinder of the engine in synchronism woth the rotation thereof. A detector 7-13 detects an ion current which is generated between the electrodes of the spark plug upon combustion of an air/fuel mixture in the cylinder. A filter 21 is connected to an input side of the detector for filtering noise contained in the ion current, the noise being induced by the ignition coil upon sparking of the spark plug. The ignition coil has a primary winding connected to the controller and a secondary winding connected to the spark plug. The filter is connected between the detector and a node P2 between the secondary winding of the ignition coil and the spark plug.

Abstract: A test and maintenance method and apparatus for an ignition system of an internal combustion engine, such as an outboard marine engine, which includes an advanced timing schedule, a nonadvanced timing schedule, and a circuit for switching between the two schedules or disabling both schedules based upon engine operating conditions. The ignition system includes an opto-electronic time base generator which produces two sets of timing pulses relative to crankshaft position which are nonadvanced timing pulses and advanced timing pulses. The time base generator comprises two LED phototransistor pairs and an encoder disk attached to the crankshaft with slots to interrupt the radiation path between each LED-phototransistor pair. The encoder disk is provided with a synchronizing slot, multiple timing slots associated with the cylinders of the engine, and a direction slot. The test function of the apparatus verifies the timing and sequence of timing pulses.

Abstract: A timing analyzer for engine diagnostic testing includes a variable sensitivity knob for testing ignition timing for both a conventional four stroke engine and a DIS four stroke engine. The timing analyzer has a pickup which is adapted to be placed around a lead from a spark plug in the engine. During spark plug firing, a current spike appears in the spark plug lead. The timing analyzer is adapted to be triggered when a current spike above a selected threshold level is detected. When the timing analyzer is triggered, a pulse of light is produced from the nose cone of the analyzer. During engine operation, the spark plugs are continuously being fired, which creates a strobe light effect from the analyzer. The timing analyzer is aimed at timing marks on the engine block, and at a single mark on the rotating flywheel, which permit the engine to be properly timed.

Abstract: An engine control apparatus for shifting an ignition timing signal to an ignition coil (48) so that the engine produces optimum torque generates a pseudo random signal (26) which is preferably an M series signal and applies the pseudo random signal to a parameter of the engine having a noise frequency component such as the engine rotational speed y(t). The M series signal is a signal having a impulse type self correlation function. A mutual correlation function of the number of revolutions of the internal combustion engine and of the M series signal is computed (30-44) and an optimum ignition advance angle is supplied to an adder (46). The adder (46) combines the optimized signal ignition advance angle with a basic ignition timing signal (.theta..sub.advB) to provide an ignition timing signal (.theta.ig) to the ignition coil (48).

Abstract: An ignition adapter for DIS four stroke engines provides conventional voltage waveforms for a diagnostic oscilloscope. Spark plug leads from a DIS four stroke engine are grouped together depending on their respective firing polarity. A first signal pickup is placed around the spark plug leads from the spark plugs of one signal polarity, for example a positive signal polarity, and a second signal pickup is placed around the spark plug leads from the spark plugs of opposite polarity, for example a negative signal polarity. A trigger pickup is placed around the #1 cylinder spark plug lead. The voltage waveforms received in the signal pickups are applied to the ignition adapter, summed and displayed on the oscilloscope as a conventional voltage waveform. The polarity of the waveform can be reversed using a polarity switch. The waveform received in the trigger pickup is applied to the ignition adapter and compared to a reference voltage.

Abstract: The voltage developed by a primary winding of an ignition coil is supplied to a voltage divider for furnishing an analog signal of reduced amplitude for evaluation on an analog basis, which reduced amplitude analog signal is averaged by a capacitor connected between the voltage divider tap and ground. The capacitor eliminates the undesired effect of voltage spikes, but is not large enough to interfere with the measurement of voltages exceeding the ignition-initiating primary winding voltage value. The same reduced primary winding voltage is supplied through an input resistor to one input of a differential amplifier connected to operate as a switch having hysteresis and having a reference voltage applied to it such that the output will be the provision of a steady voltage having a duration corresponding to the spark discharge duration, for subsequent digital evaluation.

Abstract: An ignition monitoring circuit for an ignition system of an internal combustion engine of an automobile, which comprises, in addition to a pulse height and a pulse width shaper circuit, a circuit for eliminating an initial erroneous pulse which is generated from the pulse width shaper circuit upon making of the key switch. The pulse height shaper circuit shapes impulses corresponding to an ignition voltage into pulses of predetermined height; the pulse width shaper circuit shapes the output pulses of the pulse height shaper circuit into pulses of predetermined width. The eliminating circuit comprises: a serial circuit of a resistor, a diode, and a capacitor, coupled across the battery; and a transistor, having its base coupled to the output terminal of the pulse height shaper circuit through an inverter, which is coupled in parallel with the serial connection of the diode and the capacitor.

Abstract: Engine timing apparatus includes a timing light and a pickup for producing a pickup signal in response to each ignition in a selected cylinder. The operator keys in the desired advance or retard angle in degrees in a range anywhere between +180.degree. and -180.degree.. A program-controlled microcontroller with an internaltimer samples the time period between pickup signals and, using this information and the advance of retard angle, calculates engine rpm and the proper time delay for the flash. The system automatically corrects for system delays to produce extremely accurate timing functions. The system may be used with an inductive pickup for timing gasoline engines or with a luminosity pickup for timing diesel engines. At high rpms the system produces a flash in response to every other pickup signal.

Abstract: An ignition diagnostic monitor detects ignition malfunction. A first monostable multivibrator is coupled to an ignition module to receive the ignition signal and maintain a first logic state for a predetermined first time constant after detecting an ignition signal. The monostable multivibrator maintains a second logic level state after passage of the predetermined time constant until detection of another ignition signal occurs. The second logic level indicates a missed ignition signal and an ignition fault. A control module is coupled to the ignition module and the monostable multivibrator and receives a fault detection signal from the monostable multivibrator.

Abstract: A method for detecting the ignition timing for an engine comprising the steps of detecting the production in a crank angle range outside of the range where ignition can occur of a crank angle signal by a crank angle sensor at a first time point, detecting an ignition signal corresponding to the burning flame within the combustion chamber of the engine at the second time point, calculating the time difference T.sub.o between the first and second time points, and seeking a crank angle displacement from the production of the crank angle signal to the ignition signal detected by the equation of T.sub.o /CSC.times.360, where CSC indicates a time interval between the crank angle signals and its apparatus. According to the present invention, even when the peak of the combustion light or the burning flame is detected twice for one combustion stroke, an accurate ignition timing can be detected by the detection of the first peak of the combustion light.

Abstract: A multipurpose timing light which comprises a timing light, a tachometer and a flashlight housed in a gun shaped plastic shell which in appearance is similar to the prevailing timing gun and in addition has a flashlight underneath the gun barrel and a tachometer in the rear part of the gun. This device provides illumination for the timing operation and repair work, and indicates engine speed as well as its primary function of adjusting ignition timing.

Abstract: A rotating member produces a signal corresponding to a given value M of angular rotation thereof. A clock produces pulses at a given rate. A counter mechanism is responsive to the signal and to the clock pulses for generating a number related to the number of clock pulses produced during a unit value X of rotation of the rotating member where X is unequal to M. The number may be used to determine when a value N of angular rotation has occurred.

Abstract: The adapter includes a housing containing a rectifier for supplying flash voltages to an LED. The rectifier rectifies inductive signals derived from an inductive pickup. The adapter can be used to enable a spark-ignited engine calibrator to calibrate a diesel-engine-timing meter by converting the inductive electrical signals from the calibrator to light signals for the diesel timing meter. The adapter also can be used to enable a diesel-engine-timing meter and analyze and time a spark-ignited engine by converting the inductive pulses derived from a spark plug wire into light impulses for the diesel-engine-timing meter.

Abstract: A light emission delay circuit adjusts a light emission time of a timing light into conformity with a time when a piston in an engine cylinder reaches a top dead center in detecting an ignition time for the engine cylinder. The light emission delay circuit comprises first means responsive to a first signal indicative of the ignition timing for the engine cylinder and a second signal having a leading edge substantially agreeing with the ignition time of the engine cylinder for producing a third signal having a leading edge with a leading edge of the second signal. The third signal is produced substantially two periods beyond the ignition time of the first signal, and also has a width of time equal to the period of the second signal.

Abstract: An engine timing instrument as disclosed which is particularly designed for use with diesel engines and which responds to the actual time of firing within a cylinder. A strobe may be flashed at the crankshaft angle at which firing occurs and the crankshaft of the strobe flash may be advanced with respect to the firing angle until the strobe flash occurs at a top dead center position. The angle of advance of the strobe flash is measured to then indicate the angle of firing relative to the top dead center position. Important features relates to the use of a piezoelectric transducer placed in a glow plug hole to measure pressure, the transducer being connected to circuitry which provides both a firing pulse and a reference pulse. The reference pulse occurs close to and not later than the top dead center position and is used to measure the time of a subsequent firing pulse.

Abstract: In order to monitor the correct mounting of a rotation transducer on a rotary part, the output signal of the rotation of the indicator is caused to produce a first pulse at a particular angular position. An additional reference mark transducer is coupled to the rotary part to produce a second pulse for timing comparisons with the first pulse. Mechanical slippage of the rotation transducer on the rotary part can then be detected when one of the pulses is present without the other, and the failure of either of the transducers to operate can also be detected. The device is useful for assuring reliable operation of the rotation transducer controlling fuel injection in a Diesel engine.

Abstract: A first pulse train is generated by a phase-locked loop circuit of which the frequency is adjustable to correspond to engine speeds of between 10 and 9,990 rpm. The pulse train is again divided to furnish a second pulse train for use in firing the timing light. A photoelectric sensor is responsive to flashes from the timing light. A D type flip-flop is coupled to the second pulse train and to the photoelectric sensor and generates an enable signal commencing with a pulse in the second pulse train and terminating with the sensor signal. A counter receives the first pulse train and is operative to count the pulses therein during the presence of the enable signal. A display depicts a number representative of the number of pulses counted by the counter.

Abstract: This specification discloses an apparatus and method for providing electrically distinguishable signals occurring as a function of the position of a moving element. The electrical signals are generated by a piezoelectric apparatus and can be used to determine a variable such as revolutions per minute of the movable element. Particular ones of the electrically distinguishable signals can be used for initiating a function such as the firing of the spark plugs.

Abstract: An automobile timing light for use with an internal combustion engine. The timing light includes a skip circuitry for regulating the time between flashes of a flash circuitry for permitting a sufficient charge to develop across a flash powering capacitor between successive flashes. The timing light thus provides a uniformly bright light flash irrespective of engine r.p.m.

Abstract: To positively allocate output signals from a transducer scanning marker elements arranged at a uniform distance from the center of a rotating disk, the markers are located around the circumference of the disk in accordance with a predetermined pattern, for example, uniformly distributed 30.degree. apart, or distributed with uniformly increasing relative distances, and an additional market element (33) and forming a reference marker is located in the zones between adjacent markers spaced from a neighboring marker element (21) of the plurality of marker elements by a distance which is substantially larger than the angular distance with respect to the marker element at the other side of the reference marker. The outputs from a pick-up sensor are evaluated by applying the outputs to two counters, counting a different clock rate, the count output of one of the counters being stored and compared with a subsequent count state of the other counter operating at a higher clock rate.

Abstract: An instrument of the type employed to measure the conduction angle of the ignition coil of the battery-powered ignition system of an internal combustion engine comprises input connectors which are connected to terminals of such ignition system and an evaluating circuit which generates a signal corresponding to the conduction angle to be measured by ascertaining whether an input signal derived from the input connectors rises above or falls below a predetermined threshold voltage level. For differing types of conventional ignition systems, differing threshold voltage levels are required, but instead of resorting to manual switchover to such different levels, the instrument of the invention modifies the threshold voltage level employed in automatic dependence upon the value of the input signal derived by the input connectors. The threshold voltage level assumes a first value when coil conduction ceases and a second value when coil conduction recommences.

Abstract: A self-adjusting engine timing pickup probe adapted to be received in a tubular engine mounting bracket, the probe extending into close proximity with a position indicator on a rotating engine part to provide an air gap. An elongated sensor assembly extends through the tubular member and has relative axial movement therewith for initial manual adjustment of the sensor assembly to provide an effective air gap. Interference means are provided between the tubular member and the sensor assembly, the interference means establishing substantial resistance to relative axial movement between the tubular member and the sensor assembly. The tubular member has a spring means which engages the engine mounting bracket and holds the two together in a yielding manner. The spring means urges the tubular member and associated sensor assembly inwardly toward the rotating engine part. However, during engine operation, the rotating engine part, due to tolerances, wear, vibrations, etc.

Abstract: A rotatable disk having a plurality of calibration segments and at least one marker along the peripheral portion thereof is provided while a stationary pick-up provided adjacent the disk for generating a first signal indicative of calibration segments and a second signal indicative of a reference position of the rotation of the disk. The frequency of the first signal is increased in order to accurately measure the rotational angle from the reference position.

Abstract: A signal conditioning circuit for the output of a magnetic position sensor is disclosed. The magnetic sensor generates a total output signal that increases as a function of the rotational velocity of the sensor with a spurious noise component that is a relatively constant percentage of the actual signal voltage over the speed range. In a preferred embodiment, the signal conditioning circuit discriminates between the noise component and the signal component by comparing the total signal to a variable threshold only after a positive going zero cross. The variable threshold is generated as a function of the peak amplitude of the total signal. In a second embodiment the signal conditioning circuit includes gain control means which varies the amplitude of the total output signal as a function of its peak to maintain the threshold above the noise component.

Abstract: To counteract the phase error in the signal from an rpm transducer of an engine test stand or analyzer at varying engine speeds, the signal processor of the invention receives the transducer signal whose amplitude varies with frequency and generates therefrom an output signal of constant amplitude. This signal is supplied to a threshold switch which includes circuitry for integrating periodic output signals and generating therefrom a control signal whose amplitude is proportional to the frequency of the input signal. This analog signal is used to alter the switching threshold of the threshold switch, thereby imparting to the output signal a frequency compensation which counteracts the inherent phase error and results in an output signal of constant phase with respect to the transducer signal. The apparatus of the invention is particularly useful for adjusting ignition timing, valve timing, etc. in internal combustion engines in which the input signal is derived from the crankshaft speed.

Abstract: To permit tests of: ignition timing; dwell angle; engine speed; and voltage levels, a pulse train is provided derived from the ignition system of the engine; the pulse train is applied to a frequency multiplier, preferably a phase locked loop (PLL) which provides a sequence of output pulses having a pulse repetition rate which is a multiple of the frequency of the signals or pulses of the pulse train. An AND gate has the multiplied signals applied thereto and is enabled, selectively, in accordance with the desired test. The output of the AND gate is applied to a counter which counts multiplied pulses within the interval of enabling of the AND gate, the output being applied to a digital indicator to provide a direct readable digital output; preferably, the multiplication rate is selected to provide a digital output indication which is directly readable in desired units.

Abstract: A circuit for measuring the dwell angle of an engine ignition system having contact points which close to conduct current through a coil, i.e., dwell, and which open to generate an ignition signal. The primary ignition signal is monitored and shaped to form an output voltage level for comparison against a reference voltage level of a selected percentage of car battery voltage. During the time of dwell, the ignition signal's output voltage level is less than the reference voltage level causing a voltage comparator circuit to direct a relatively constant and independent current to a meter for visual display of the dwell time in terms of dwell angle. The extent of dwell angle displayed is determined by the ratio of the time period over which current is delivered to the metering circuit to the total time between spark plug firings, properly calibrated for the type of engine being tested.

Abstract: The apparatus for testing a device controlling the ignition of an engine comprises rotary driving means for driving the device and simulating the driving of the device in normal operation; an angular encoder mechanically coupled to the driving means for providing a series of clock pulses the frequency of which is a function of the speed of rotation of the driving means; means for producing a pulse signal representing the ignition initiating signal delivered by the device when it operates in the course of its use with the internal combustion engine; at least one circuit for measuring an angular parameter of operation of the device, the measuring circuit being connected to the encoder and to the pulse signal producing means for producing a measurement signal formed by a series of measurement pulses each of which occurs respectively in the course of a revolution of the driving means, each pulse representing the angular parameter to be measured and a display device for displaying the number of clock pulses occurr