Abstract: The air/fuel ratio of the mixture supplied to an internal combustion engine is controlled to a lean limit resulting in a maximum engine operating roughness at one level during off-idle operation and a higher level during idle conditions. Roughness is detected by comparing the minimum engine speed attained during each cylinder combustion cycle to the average of the minimum speeds.

Abstract: A fuel control system for an internal combustion engine in which the idle fuel quantity is adjusted to maintain a predetermined desired idle speed and in which the transition between the idle fuel quantity and a scheduled off-idle fuel quantity is blended to provide for smooth engine operation.

Abstract: Minimum and maximum fuel delivery of a mechanical diesel engine fuel injector is limited by the use of a single actuator which provides for a minimum fuel limit or maximum fuel limit in accord with a predetermined schedule. A failsafe mode of operation of the engine is provided in the event of a failure of the actuator.

Abstract: A system for providing the fuel requirements of an engine based on an estimated value of the temperature of the intake region of the engine.

Abstract: A fuel control system for an internal combustion engine senses a failure in the coolant system and supplies fuel alternately to each of the two cylinder banks for predetermined periods of time so that one of the cylinder banks is supplied with an air and fuel mixture to power the engine and the other one of the cylinder banks is supplied with air only to be cooled thereby to extend the safe operating time of the engine. The air/fuel ratio of the mixture supplied to the bank provided with a combustible mixture is adjusted to limit the speed of the vehicle to further extend the safe operating time of the engine.

Abstract: A system is described for generating an engine camshaft sync pulse having a constant predetermined crankshaft angle relation to the top dead center position of a designated one of the cylinders of the engine to enable synchronization of the fuel injection sequence with the ignition sequence without the requirement of a camshaft position sensor.

Abstract: An apparatus for igniting the particulates trapped in a particulate filter used with a diesel engine supplied with fuel with an agent for reducing the ignition temperature of the particulate when it is determined that a predetermined concentration of particulates at which the particulates will undergo self-sustained combustion have accumulated in the filter.

Abstract: An operational amplifier includes a PNP differential amplifier operable for low common mode input voltages and an NPN differential amplifier operable for high common mode input voltages so that the operational amplifier is operable over a range of common mode input voltages that includes substantially the positive and negative supply voltages.

Abstract: An up-down voltage regulator includes an up regulator followed by a series pass PNP transistor. The base of the PNP transistor is coupled to an unregulated voltage source. The up regulator is responsive to the voltage at the collector of the PNP transistor to control the emitter voltage of the PNP transistor for all values of the unregulated voltage source to bias the PNP transistor so as to establish and maintain the collector voltage of the PNP transistor at a desired regulated value.

Abstract: An internal combustion engine misfire detection system is described which counts the transitions in the output of an oxygen sensor in a closed loop air/fuel ratio controller over a predetermined time period and compares the transition count with a limit count determined to be the number which would occur at the engine speed during a misfire condition. When the number of transitions exceeds the limit count, a warning lamp is energized and secondary air to an oxidizing converter is diverted to the atmosphere.

Abstract: A mass air flow meter for an internal combustion engine is described in which the mass air flow into the engine is determined by the measured throttle angular position, the sensed pressure above the throttle and a stored schedule of values dependent upon the ratio of the pressure below the throttle to the pressure above the throttle.

Abstract: A fuel limit controller includes a computer supplying a commanded absolute EGR control pressure that is a measure of fuel supplied per diesel engine revolution. An absolute EGR control pressure equal to the commanded absolute pressure is generated from a subatmospheric pressure source and atmospheric air so that the absolute EGR control pressure is limited to atmospheric pressure. Fuel per engine revolution is limited to the value represented by the absolute EGR control pressure so that the fuel limit is automatically compensated for altitude variations. The rate of change in the fuel limit in response to changes in the absolute EGR control pressure is limited to delay increases in fuel to match the time to purge excess exhaust gases from the engine intake manifold.

Abstract: A fuel injection system for a motor vehicle internal combustion engine includes a controller that energizes an electromagnetic fuel injector for time durations determined to provide the fuel requirements of the engine. The fuel injection system is calibrated to the actual fuel flow rate of the injector by a calibration resistor provided with the injector assembly having a resistance related to the actual fuel flow rate of the injector. The controller samples the resistance of the calibration resistor and retrieves a number related to the actual fuel flow rate of the injector from a lookup table in a memory containing fuel flow rate information at locations addressed by resistance values. The retrieved fuel flow rate information is then utilized to determine the time duration required to energize the injector to obtain the required amount of fuel.

Abstract: A motor vehicle combustion engine has an exhaust gas recirculation system in which the flow of recirculated exhaust gas is controlled through an orifice having exhaust back pressure on one side and a control pressure on the other as determined by an EGR valve. A pressure transducer compares the control pressure with a reference pressure provided in part by an electromagnetic force to provide an operating pressure for positioning the EGR valve to obtain a control pressure equal to the reference pressure. At engine idle, the EGR valve is closed and the control pressure is equal to the exhaust back pressure. When this condition exists, the electromagnetic force is varied until the reference pressure is substantially equal to the control pressure, the magnitude of the electromagnetic force being a measure of the control pressure at idle and which comprises a calibration value that is stored for use as a reference for controlling exhaust back pressure during other engine operating conditions.

Abstract: A temperature stabilized voltage reference is generated based on the difference in the base to emitter voltages of a pair of transistors operating at different current densities which is summed with a voltage that is a predetermined fraction of one of the base emitter voltages. This voltage is utilized to provide for a constant current through a load by adjusting the current through a sense resistor to the value of the temperature stabilized voltage.

Abstract: An exhaust gas recirculation control system variably controls the amount of exhaust gas recirculated to a diesel engine in accord with the quantity of fuel supplied per engine revolution between a maximum amount at a first predetermined quantity of fuel per revolution and a minimum amount at a second predetermined quantity of fuel per revolution. The system maintains a substantially constant relationship between the exhaust gas recirculation amount and the quantity of fuel injected for each revolution over the speed range of the engine even though the fuel control element positions providing the first and second predetermined values of fuel quantity per revolution each increases at different rates as a function of increasing engine speeds.

Abstract: An automatic vehicle engine stop-restart system responsive to throttle position is disclosed in which the engine is shut down by disabling the fuel supply in response to a closed throttle and restarted in response to an open throttle. During shutdown, the intake manifold is primed with an air and fuel mixture just prior to the stopping of the engine to provide an immediate restart capability.

Abstract: The position of a limit stop member which limits the mechanical position of a fuel metering valve in a diesel engine fuel injection pump is open loop controlled to a position offset from a desired fuel metering valve limit position by an amount in the increased fuel direction that is equal to the maximum possible error in the open loop controlled positional relationship between the limit stop and the fuel metering valve. The position of the fuel metering valve is sensed and compared with the maximum desired metering valve limit and when the fuel metering valve position exceeds the limit position, the position of the limit stop is closed loop adjusted to the maximum fuel metering valve position.

Abstract: An automatic engine stop-restart system responsive to throttle position is disclosed in which the starter motor is energized and the forward drive clutch engagement force is slowly increased in response to a throttle opening commanding an automatic standing start and the starter motor is energized and the forward drive clutch engagement force is rapidly increased in response to a throttle opening commanding a driveaway start.

Abstract: The values of dwell and ignition timing signals from which ignition dwell and spark timing are provided are controlled to minimize power dissipation in an electronic ignition system and to ensure that adequate dwell times are provided during engine acceleration conditions and large advance angle increases. The dwell signal is increased from a static dwell value during steady state engine operation to a higher value in response to sensed engine accelerating conditions and the change in the spark advance between ignition events is limited to ensure that an adequate dwell period is provided.