Chrysler Corporation

Martin G Yagley

Jan S Pyko

Anson Lee

Douglas C Frantz

Min Sway-Tin

Geoffrey S Matthews

Maura P O'Kennedy

A knock sensor diagnostic circuit for use in an automobile by using the reciprocal electromechanical properties of resonators.

Knock sensor diagnostic system

A diagnostic method is provided for sensing whether an oxygen sensor is still suitable for use in measuring the fuel-air mixture in the exhaust gases of an internal combustion engine. The method involves turning off a heater of an oxygen sensor when the engine is turned off and allowing the sensor to cool. While the sensor cools, the sensor resistance is measured by means of a large pull-up resistor and a small pull-up resistor, with the small resistor being switched into the circuit at regular intervals for a short period of time. The use of the small pull-up resistor not only increases the reliability of the measurements, but also aids in quickly determining when the sensor resistance has increased above a threshold value indicating the sensor is cool. When the sensor is sufficiently cool, the heater is turned on and the sensor is monitored for a decrease in resistance, indicating that the heater is functioning properly.

Oxygen heater sensor diagnostic routine

A method for firing a spark plug in an engine which employs a simulated high data rate signal. The simulated high data rate signal is generated by a preselected number of gaps in a flywheel within a predetermined time segment of each cylinder event time called the spark event. A sensor generates the simulated high data rate signal as the gaps rotate past it. Data pulses are generated and stored within the spark event. In the case of distributorless ignition systems, the spark plug to be fired is identified. In one embodiment, a widened gap in the flywheel is used to perform this identification. The occurrence time of the leaading and trailing edges of the data pulses are received and stored. The rate of rotation including velocity and possibly acceleration is calculated and stored upon the occurence of each pulse. The spark firing time within the spark event is calculated and stored upon the occurrence of each pulse. Finally, the spark plug is fired once within the spark event.

Method for firing spark plugs

Electrical power for an electrically heated vehicle windshield is controlled by an arrangement utilizing a modified alternator coupled to the windshield heater via an autotransformer. In a high power mode, the vehicle battery is coupled to a center tap of the alternator, while in a normal power mode the vehicle battery is coupled to a conventional rectified output of the alternator. A microprocessor controlled silicon controlled rectifier bridge provides direct current to the windshield heater element by rectifying the output of the autotransformer. Additionally, a current sensor coupled to the heater element is utilized by the microprocessor to determine the electrical resistance of the heater element in order to take required diagnostic measures.

Electrically heated windshield controller

A system for providing individual engine cylinder spark deration in response to detonation.

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Sterling Heights, MI, United States of America

Martin G Yagley