Abstract: A method is disclosed for controlling operation of an engine coupled to an exhaust treatment catalyst. Under predetermined conditions, the method operates an engine with a first group of cylinders combusting a lean air/fuel mixture and a second group of cylinders pumping air only (i.e., without fuel injection). In addition, the engine control method also provides the following features in combination with the above-described split air/lean mode: idle speed control, sensor diagnostics, air/fuel ratio control, adaptive learning, fuel vapor purging, catalyst temperature estimation, default operation, and exhaust gas and emission control device temperature control. In addition, the engine control method also changes to combusting in all cylinders under preselected operating conditions such as fuel vapor purging, manifold vacuum control, and purging of stored oxidants in an emission control device.

Abstract: An engine control system includes an adaptive bias sub-system (100) that generates bias values for controlling the air-fuel ratio. The sub-system (100) includes an integral controller (118) that reads an error signal from a post-catalyst switching EGO sensor (112). A plurality of noise isolation integrators (122) filter any noise resulting from a particular engine operating condition (e.g. acceleration, deceleration, idling) from the integrated error signal and stores the signal in a corresponding keep-alive memory (124) as a bias value for that engine operating condition. In a preferred embodiment, the post-catalyst feedback loop includes a gated proportional controller 116 that turns on for a limited period of time after the post-catalyst switching EGO sensor (112) switches states.

Abstract: A method for controlling a powertrain of a vehicle is described. The method determines a desired vehicle condition based on three driver actuated elements. In a preferred embodiment the first element can be pedal position, the second element can be a brake actuator or, more specifically, brake actuation duration, and the third element can be a gear selection lever. Further, the desired vehicle condition can be desired powertrain output, vehicle acceleration, or various other parameters.

Abstract: A night vision system 10 is provided for detecting objects at relatively low visible light levels. The system 10 includes an infrared light source 14. The system 10 further includes a thin sheet optical element 16 extending along a first axis 27 receiving light from the infrared light source 14 and reflecting the light generally in a first direction. Finally, the system 10 includes an infrared camera for receiving the light reflected off objects in the environment and generating a video signal responsive to the received light.

Abstract: A carbon monoxide sensor placed downstream of the catalytic converter and a temperature sensor placed upstream of the converter in a diesel engine provide information to build a real time CO conversion efficiency versus catalyst temperature curve to determine whether a catalyst has deteriorated beyond a predetermined point with respect to On-Board Diagnostic (OBD) requirements. Pre catalyst CO concentration is inferred from the engine operating conditions, and catalyst temperature is determined using the temperature sensor output and the engine exhaust flow heat transfer model. The real time curve is compared to a reference curve to determine catalyst performance. Catalyst performance with respect to CO conversions can then be correlated to that for HC and NOx to meet OBD requirements.

Abstract: An exhaust gas treatment system for an internal combustion engine includes a pair of upstream emission control devices which respectively receive the exhaust gas generated by a respective group of cylinders, and a single, shared downstream emission control device receiving catalyzed exhaust gas from each of the upstream emission control devices. After the downstream device stores a selected constituent gas generated when each cylinder group is operating “lean,” the downstream device is purged by operating the first cylinder group with a stoichiometric air-fuel mixture while operating the second cylinder group with a rich air-fuel mixture, such that the combined catalyzed exhaust gas flowing through the downstream device during the purge event has an air-fuel ratio slightly rich of stoichiometry. As a result, the invention improves overall vehicle fuel economy because only one of the upstream devices is purged of stored oxygen when purging the downstream device of previously-stored constituent gas.

Abstract: A method for diagnosing engine thermostat is presented. Indicated engine coolant temperature is estimated based on engine operating conditions, such as engine speed, net engine torque, air flow, fuel-air ratio, net engine torque, etc. This estimate is compared to the reading of the engine coolant temperature sensor in areas below the temperature at which the thermostat starts to open and above in order to detect degradation in the performance of the sensor or the engine thermostat. If the estimate and the reading agree in one area and disagree in the other, then the thermostat performance is degraded. If the estimate and the reading disagree in both temperature ranges, then the coolant sensor performance may be degraded.

Abstract: A method for determining deterioration of an exhaust gas sensor coupled downstream of an emission control device by monitoring the sensor's response to a change in an air-fuel ratio is presented. In particular, the sensor is monitored for a predetermined time period following a switch from lean to rich operation and a ratio of a maximum and minimum value is determined. The ratio is then compared to a threshold value to evaluate sensor performance. This method achieves improved emission control and fuel economy.

Abstract: A pulse width modulated driver 20 is provided for driving a load 17, such as a halogen bulb, at a reduced voltage level. The driver 20 includes a switch 28 selectively opening and closing to apply a pulse width modulated signal VPWM to a high voltage end of the load 17. The switch 28 operates responsive to a switch control signal VS. The driver 20 further includes a duty cycle control circuit 26 generating the switch control signal VS when an input operational voltage Vo is above a threshold voltage level. Finally, the driver includes an energy storage circuit 24 for storing electrical energy when the switch 28 is open to maintain the input operational voltage Vo above the threshold voltage level. The driver 20 is connected on a high side of the load 17 and does not require a separate line connected to system ground.

Abstract: A capacitance transducer has a first hermetically sealed cavity adapted to deform in response to an applied force, such as pressure or acceleration, and a second hermetically sealed cavity adapted to resist deformation in response to such applied force. The cavities are formed between two doped silicon layers separated by a selectively etched electrically insulating spacer layer. Multiple medial electrically insulating cavity area spacer segments within the second cavity resist deformation thereof in response to the applied force to be measured. The capacitance transducer can be manufactured from doped silicon wafers using well developed silicon wafer processing techniques.

Abstract: A flexible fuel dielectric-effect sensor is disclosed wherein three capacitors, immersed in the fuel flow, are connected to define a pi filter.

Abstract: A mass airflow based control system for an internal combustion engine is provided which is capable of inferring barometric pressure surrounding the engine. The control system determines the air charge going into the engine from a measured value of mass airflow, and compares this value with a predicted value of air charge going into the engine, which the control system infers. Differences between the two values are first attributed to inlet air temperature, which is measured, and then to a change in barometric pressure, which is the inferred barometric pressure.

Abstract: A system and method for estimating hill slope and coefficient of friction for a road surface from vehicle and engine measurements. A first variable related to hill slope and a second variable related to road surface coefficient of friction are generated from the vehicle and engine measurements and may be used in a variety of control applications. The method includes the steps of generating a first variable related to the slope of the hill and a second variable related to the coefficient of friction of the road surface. The hill slope can be determined from the first variable and the coefficient of friction of the road surface can be determined from the second variable. These estimated values can then be used in control applications. The braking and traction control systems of a vehicle respond to a first variable related to hill slope and a second variable related to road surface of coefficient of friction.

Abstract: A high voltage switching circuit is provided for electrically coupling, or decoupling, a high voltage power supply to, or from, a load selectively in accordance with a control signal. The circuit converts the control signal to a radiant energy signal. A plurality of switching modules serially is coupled between the load and the high voltage power supply, each one of such modules including drive circuitry for converting the radiant energy into drive signals for a switching transistor which drives such transistor between a conducting and non-conducting condition selectively in accordance with the drive signal. With such arrangement, each of the modules develops its own drive signal in response to the radiant energy signal so that each drive signal is self-referenced to the reference potential of the module.