Abstract: The amplitude of peak to peak air to fuel ratio variation of an internal combustion engine is modulated as a function of catalyst temperature.

Abstract: An improved electronic mass airflow sensor circuit and method for manufacturing that circuit are disclosed. The circuit includes primary and secondary sensor elements having non-zero temperature coefficients of resistance. The circuit further includes a thick film resistor electrically connected to the secondary sensor element to form a combination element such that resistance ratio of the primary sensor element to the combination element remains constant over varying temperatures. The method includes the steps of detecting the resistance of the primary and secondary sensor elements, generating primary and secondary electrical signals corresponding thereto, and placing the thick film resistor in electrical contact with the secondary sensor element to form the combination element.

Abstract: An electronic engine controller includes a central processing unit (CPU) which controls the operations of the controller and an analog-to-digital (A/D)converter chip which receives analog signals generated by sensors which transmit signals indicative of vehicle and engine operating parameters. The A/D converter chip automatically performs a conversion on certain signals indicative of critical engine operating parameters to generate corresponding digital values upon each engine revolution. These digital values are stored for retrieval by the CPU. Digital values corresponding to other signals are generated and transmitted upon request by the CPU. The A/D converter chip and the CPU are coupled by a serial link which operates under one of several protocols to transmit digital values from the A/D converter chip to the CPU.

Abstract: A method and system for reducing emissions from an engine during periods of partial or total heated exhaust gas oxygen (HEGO) sensor failure. A switch point is stored in an electronic engine control for use in controlling the fuel delivered to the engine based on the value of the signal generated by the oxygen sensor relative to the switch point. The method includes the step of sensing the current of the heater element of the HEGO sensor. The sensed current is compared to a first predetermined current threshold which indicates a degradation of the HEGO sensor. A degradation of the HEGO sensor introduces a bias signal to the electronic engine control. If the current of the heater element is below the first predetermined current threshold but not below a second predetermined current threshold, the switch point is changed so as to compensate for degradation of the oxygen sensor.

Abstract: A mass air flow sensor is calibrated by exposing it to known air flow and measuring the input and output voltage to a calibratable output stage. In the absence of air flow, the output stage is then calibrated to produce a desired output voltage in response to an application of the measured input voltage.

Abstract: The present invention is directed to an on-board diagnostic system for detecting a malfunctioning fuel pump in an internal combustion engine during engine operation. Pressure sensor means are provided for sensing fuel pressure in the fuel supply line and for generating corresponding pressure signals. Signal processing means receive and process the pressure signals from the pressure sensor means. An output signal is generated by the signal processing means if pressure signals are determined to correspond to a defective fuel pump Such output signal can be stored, used to alert an engine operator to an impaired fuel pump and/or provided to a fuel injector control means for adjusting fuel flow.

Abstract: An electrical connector has a first connector body which has a deflectable locking member with an engagement catch and a second connector with an opening for receiving the locking member and engagement catch. A coupling assurance device can be positioned in the first connector body and allow coupling of the first and second connector bodies, due to the flexibility of the locking member, and yet prevent unintentional decoupling of the first and second connector bodies unless the coupling assurance device is removed.

Abstract: A method of controlling the operation of heaters for an exhaust gas oxygen sensor as function exhaust gas temperature as compared to a first exhaust gas temperature to turn on the heaters and a second exhaust gas oxygen sensor temperature to turn off the heaters.

Abstract: A method for calibrating the response time of a mass air flow sensor in which the sensors bridge offset voltage is measured and the constant C.sub.I is calculated from the initial value of the bridge offset voltage. C.sub.I is a constant of the heated resistor's resistance in the equation RH=C+(1/I.sub.H) C.sub.I. The response time of the mass air flow sensor is a function of C.sub.I. A bridge offset voltage required to give C.sub.I a desired value is calculated. A pair of biasing resistors are trimmed while monitoring the value of the bridge offset voltage until the monitored value of the bridge offset voltage is equal to the desired value.

Abstract: The present invention is directed to an on-board diagnostic system for detecting a defective fuel line pressure regulator in an internal combustion engine during engine operation. Pressure sensor means are provided for sensing fuel pressure in the fuel supply line and for generating corresponding pressure signals. Signal processing means receive and process the pressure signals from the pressure sensor means. An output signal is generated by the signal processing means in the event pressure signals are determined to indicate a malfunctioning pressure regulator. Such output signal can be stored, used to alert an engine operator to an impaired regulator and/or provided to a fuel injector control means for adjusting the duration of injector actuation to better achieve a desired fuel flow quantity per individual actuation.

Abstract: An Electronic Engine Controller (EEC) is calibratable to control the rate at which fuel is delivered to an intake of an internal combustion engine in order to achieve a bias in the air/fuel ratio combusted by the engine. The EEC operates under closed-loop control to alter the fuel delivery rate in response to an output of an oxygen sensor which detects the concentration in exhaust gas produced by the engine. The EEC achieves a predetermined bias, in the air/fuel ratio, which is in a rich or lean direction from stoichiometry, by maintaining the fuel delivery rate at a jump value upon the indication by the oxygen sensor of an air/fuel ratio in the same direction from stoichiometry as the desired bias. The fuel delivery rate is maintained at the jump value for a variable period of time, which preferably depends upon the engine speed and load. Upon expiration of the variable period of time, the fuel delivery rate is abruptly altered to a fuel delivery rate corresponding to a predetermined air/fuel ratio.

Abstract: A method and system for determining absolute rotor position with a Variable Reluctance (VR) motor. An inductance sensor is compatible with the VR motor and is adapted to generate a plurality of variable inductance values corresponding to the position of the rotor. The inductance values may be plotted during calibration as phase-separated pseudo-sinusoidal waveforms with a resultant inductance/position profile having near-linear regions with determinable slopes and offsets. Excitation electronics converts variable inductance values to corresponding digital values which are suitable for computer processing. A micro computer is adapted to determine which of the digital values is a mid-value and to convert the mid-value to high resolution motor rotor angular units in accordance with the calibration-determined slopes and offsets.

Abstract: An evaporative purge flow monitoring system is provided for use in a motor vehicle having an internal combustion engine, a fuel tank, and an evaporation canister in communication with the fuel tank and the engine for trapping and subsequently reusing fuel vapor dispelled from the fuel tank. The evaporative purge flow monitoring system includes a vapor management valve interposed between the engine and the evaporation canister. An Electronic Engine Control (EEC) assembly is further provided in communication with the vapor management valve and the engine wherein the EEC assembly is provided with a test logic to determine satisfactory operation of the vapor management valve. The test logic determines whether the vapor management valve is defective based on either the presence of significant fuel vapor as determined by the test logic or a change in an engine performance parameter generated within the EEC assembly without requiring a separate sensor when the vapor management valve is temporarily closed.

Abstract: This invention includes straightening and curving air flow within an environmental test chamber so as to improve the testing of a mass air flow meter by maintaining a uniform air flow velocity profile and constrain the size of the environmental test chamber. Such size constraint facilitates the task of maintaining a desired environment within the chamber.

Abstract: A method, for use with a vehicle including a multi-cylinder internal combustion engine having exhaust valves, for controlling the temperature of the exhaust valves during fuel cutoff modes of engine operation utilizing a bit pattern representation of the engine cylinders. The method includes cutting off the fuel delivered to the cylinders in an indexed cylinder firing pattern to vary which cylinders receive fuel, so as to maintain acceptable exhaust valve temperature levels. The method may also include operating the engine with a lean air/fuel ratio, so as to maintain acceptable catalytic converter temperature levels.

Abstract: An automated method for generating compensation values for use in an electronic engine controller during transient engine operation comprises an initial step of exposing an engine to an ambient temperature value to set the engine to an initial start temperature. The engine is started and operated in a predetermined manner until the engine reaches a stable operating temperature. The mass flow rate of air into an induction system of the engine is detected to generate a plurality of air flow values, the temperature of engine coolant is detected to generate a plurality of engine coolant temperature values and the composition of exhaust gas produced by the engine is detected to generate a plurality of exhaust gas values. The detected air flow values, engine coolant temperature values and exhaust gas values are stored in a data storage means. The engine is exposed to a plurality of ambient temperatures to generate data indicative of engine operation from a plurality of initial start temperatures.

Abstract: An adaptive fuel control system and method directed for use in a motor vehicle powered by a fuel-injected engine and having a fuel tank and a fuel rail and which is operative to run on a plurality of fuels and fuel blends. The system includes a refueling mixer which acts as a fluid damper to slowly introduce new fuel into the fuel rail and correspondingly slow the rate at which new fuel composition is mixed with existing fuel. A stratification mixer is also utilized to re-mix components of blended fuels which may have separated at cold temperatures. An Exhaust Gas Oxygen sensor (EGO) monitors engine exhaust gases and generates a corresponding electrical signal when the air/fuel mixture of the fuel switches between rich and lean. Finally, an electronic control assembly communicates with the EGO and the fuel injectors to generate and store in memory an updatable extended adaptive fuel control table of air/fuel ratio multipliers for selected engine load/engine speed cells.

Abstract: Exhaust gas constituents of an exhaust gas stream are measured by drawing a proportional sample of exhaust gas through a capillary tube inserted into the exhaust gas stream. The capillary tube is controllably heated to avoid distortion of the reading due to condensation. The mass flowing in the capillary tube is determined by sensing the pressure drop across the length of the capillary tube.

Abstract: A method and apparatus for calibrating a mass air flow sensor in which the sensing elements of the sensor are subjected to an oscillating mass air flow summed with an offset mass air flow to produce the summed mass air flow. The output waveform of the mass air flow in response to the summed mass air flow is displayed on a display having a desired waveform superimposed thereon. Selected resistors in the sensor's electronic circuit are then trimmed to conform the waveform output by the mass air flow sensor with the superimposed desired waveform.

Abstract: A method is provided, for use in controlling an apparatus or for use by a controller of apparatus, for estimating a single torque variable utilizing multiple models. In one embodiment, the apparatus is a vehicle. The method includes the steps of sensing operating parameters to obtain associated operating signals and obtaining estimates of the torque variable from at least two independent models. Each model generates a torque estimate signal based on the operating signals. The method also includes the steps of weighting the individual torque estimate signals according to a predefined accuracy of the associated torque model, to obtain a plurality of weighted individual torque estimate signals, and generating a final torque estimate signal based on the weighted individual torque estimate signals. Once the final torque estimate signal is obtained, the apparatus can be controlled based on the final torque estimate signal.