Abstract: An ignition secondary sensor is provided which is disposed in a high voltage path between an ignition coil and a spark plug for use with a detecting circuit for detecting ignition current and ion current flowing through a spark plug. The sensor comprises an ignition path connected in series with the high voltage path and having a pair of reverse current preventing diodes and a detection path connected to a spark plug side end portion of the ignition path and having a pair of current detecting diodes. A path portion of the detection path on the side of the current detecting diodes opposite to the ignition path and a path portion of the ignition path connecting between the reverse current preventing diodes are capacitively coupled. The detecting circuit is connected to the sensor for detecting the ignition current (ignition timing) on the basis of current flowing into the sensor therefrom and the ion current (combustion timing) on the basis of current flowing from the sensor thereinto.

Abstract: A detector for detecting a secondary voltage supplied to a spark plug of an engine comprises a rubber tube mounted on a high tension cord and equipped with a detecting electrode, and a shield case or shield layer enclosing the rubber tube. The rubber tube is made up of first and second semicylindrical rubber members joined together into a tubular shape. The detecting electrode is U-shaped and has a middle portion embedded in the first rubber member and left and right ends which project, respectively, from left and right joint surfaces of the first rubber member, and are sheathed in grooves in left and right joint surfaces of the second rubber member. A lead wire is connected to one of the left and right projecting ends of the detecting electrode. This structure of the secondary voltage detector can facilitate the production process.

Abstract: Apparatus for detecting and displaying the revolution speed of an internal combustion engine having an electrical distribution system including at least one spark plug includes a hand held housing having a digital display. An antenna is connected to the housing which is for placement adjacent to the spark cable. A pulse to direct digital interphase circuit is in the housing and counts the electrical energy pulses received by the antenna from the spark cable within a predetermined time frame to determine electrical pulse frequency and to convert the determined electrical pulse frequency into internal combustion engine revolution speed and to display the internal combustion engine revolution speed on the digital display.

Abstract: A sparking voltage detecting device for an internal combustion engine having an ignition system having at least one secondary side high-tension cord, is mounted on the secondary side high-tension cord, for detecting sparking voltage generated in the engine. A main body formed of an insulating material has at least one through hole formed therein. The main body includes a pair of halves fabricated separately at least in part from each other and abutting each other along a line extending through the center of the main body. The high-tension cord is fitted through the through hole in a liquidtight manner. At least one conductive member is embedded in the main body at a location radially outward of the through hole and spaced from the high-tension cord by a predetermined distance.

Abstract: An ignition detecting device for use in an internal combustion engine. An ignition surge current detector detects an ignition surge current due to capacitive discharge of the ignition coil. A comparator compares an output voltage detected by the ignition surge current detector with a predetermined reference voltage to detect accurately occurrence or non-occurrence of ignition spark.

Abstract: The method and apparatus allows the detection and indication of anomalies in the operation of the ignition system of an internal combustion engine including a plurality of spark plugs, each of which receives a periodic high-voltage pulse output by a high-voltage generator in operation. The method includes the steps of:detecting the pulses generated by the high-voltage generator,comparing the peak values of each pulse detected with first and second threshold values, andproducing a perceptible signal when the peak values of the high-voltage pulses fall outside the acceptable range defined between the threshold values.

Abstract: An analyzation apparatus for ignition systems that has a pulse detector circuit that generates and converts an AC signal into a DC signal, filters unwanted signals and allows the user to adjust the amplitude of the signal to accommodate differing ignition systems. A pulse stretching circuit is included to increase the duration of the signal and an analog driver circuit is included to convert the signal received by it to a linear voltage suitable for driving two LED display circuits. The LED circuits are connected in parallel with the driver circuit and the visual display of the LED circuits show a display proportional to the amplitude of the signal received from the driver circuit. The LED displays show the amplitude of the signal. The LED circuits have diodes the prevent current flow between adjacent LED's of the adjacent LED circuits. The apparatus includes a function switch to select the LED circuit desired and to interrupt power to the apparatus. A portion of the elements are enclosed in a case.

Abstract: In a multiple-measurement system, a weighted sum of the measurements is used to provide a selective image. An additional weighted sum is used to provide an increased signal-to-noise ratio image. An improved selective image is formed by combining the low frequency portions of the selective image and the correct high frequency componenets from the increased signal-to-noise ratio image. To provide the correct high frequency components the error between the selective image and the improved selective image is minimized. The low-noise high-frequency image is weighted by the ration of the cross correlation of the selective andlow noise images divided by the autocorrelation of thelow noise image.

Abstract: A semiautomated diagnostic apparatus primarily used with ignition systems on internal combustion engines is novel in that every firing is examined for peak breakdown voltage level in a synchronized sequential manner to create a display of abnormalities and sequence number identification. Normal conditions can also be displayed in sequence when desired. A variable input permits examining relative peak voltages for further user analysis. An acoustic alert is provided as is an RPM indication and novel realtime indication of spark advance angle. The system operates at any engine speed.

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: This specification discloses testing vehicle primary ignition systems by taking the integral of the primary spark plug firing voltage versus time over a time period when the spark should occur. To determine when an integration output should be evaluated, a phase locked loop circuit is used to predict the occurrence of an ignition firing pulse. To compensate for changes in engine speed and yet disregard extraneous spark plug firings, the phase locked loop circuit contains two loop filters having different response times which are automatically selected to minimize response to erroneous or missing spark plug firings and maximize response to actual engine RPM changes.

Abstract: A diagnostic apparatus for an internal combustion engine ignition system measures the rise of the secondary voltage at the ignition coil represented by time lapse between initiation of the secondary voltage rising and occurrence of break and the ignition coil primary breaking current value. Results of the measurement are computed to determine stray capacitance existing in the internal combustion engine ignition system and secondary voltage.

Abstract: An ignition system for internal combustion engine, which controls the ignition coil primary current according to the magnitude of the floating capacitance in the secondary side wiring section of the ignition coil, by determining the floating capacitance from the negative slope of rising of the secondary voltage produced in the ignition coil in response to the cutoff of the primary current and the primary cutoff current value, the slope being determined by measuring the period T until the secondary voltage reaches a predetermined voltage value. When the floating capacitance is increased, the primary cutoff current value is increased to increase the coil energy so as to increase the secondary voltage generated in the ignition coil for preventing the generation of a miss-spark.

Abstract: A portable electronic device for application in the diagnosis of automotive ignitions system failures is described. A novel probe is described, which can detect and differentiate the voltage on a typical ignition cable or spark plug. Means are provided to shield the differentiating sensor from extraneous fields and to process the differentiated signal to provide simple indications of failure of ignition system components and to identify such components for replacement.

Abstract: An ignition circuit tester including a pick-up coil assembly for inductive coupling with and location closely along a circuit element to be tested, an amplifier circuit for amplifying a signal picked up by the coil assembly, and a meter to indicate the signal.

Abstract: Apparatus for measuring a high voltage in an ignition circuit, in which voltage dividing means has a first arm for connection to a point of measurement in said circuit and a second arm connected to a rectifying means. The output of the rectifying means is connected to means for matching impedance at the rectifying means to a direct current voltage display means connected to the output of the impedance matching means such that a displayed voltage is related to the high voltage in the ignition circuit. Low voltage measuring circuitry is also present which is connectable directly to the display means without the use of an impedance matching circuit.