Abstract: A knock control system for internal combustion engines comprising a knock sensor and a knock detection circuit that uses an electronic engine controller. The knock sensor creates an electrical output signal indicating the presence of engine structure vibrations resulting from engine combustion characteristics. The circuit filters the knock sensor signal, time gated at independent crankshaft angles, and transfers it to a noise channel and to a knock channel. A comparator distinguishes between background vibration and vibrations during the combustion event that are due to knock. The knock detection function, along with the crankshaft angle position reference signal, develops time gated "snapshot" signals indicating the magnitudes for both the background noise and the vibrations created by denotation and distinguishes between them.

Abstract: A method for extending the range of operation of an electromagnetic fuel injector for an internal combustion engine employs a technique for reducing the time required for the injector to open while at the same time allowing the injector to maintain a minimum closing time. Prior art techniques have utilized a regulated voltage supply to determine the precise voltage applied to the inductive element of the injector to cause it to open. The present invention does not regulate the applied voltage, but instead the invention allows an unregulated battery or other DC supply voltage to be applied to the inductive element to cause the injector to open as rapidly as possible. The current in the injector is sensed to allow a reduction in the applied voltage when a predetermined maximum current occurs in the inductive element. The voltage reduction permits a holding current to be established in the inductive element to maintain the injector open.

Abstract: An analog computer circuit for controlling a fuel injection system during engine cranking. The fuel injection system has an electrically controllable fuel injector that is intermittently actuated. The analog computer circuit develops a logic level signal having cyclically recurring time intervals that vary depending upon the manner in which a capacitor is charged from a DC voltage supply. Several electrical impedances are selectively placed in circuit with the capacitor and the voltage supply to control its rate of charging during engine cranking.

Abstract: A fuel injection control system utilizes a microprocessor to calculate and generate one or more logic control signals that determine the duration of the energization time of intermittently energized electromagnetic fuel injectors. The microprocessor has a number of inputs which are indicative of engine operation, such as intake manifold vacuum, engine crankshaft position and speed, engine operating temperature, and perhaps less important parameters. During engine cranking most of these parameters are not available. The invention overcomes this problem with the use of an analog computer that shares circuitry used by the microprocessor when the microprocessor is either in a default mode of operation or when the engine is being cranked.