Abstract: A multi-mode internal combustion engine is described. As one example, the engine may be transitioned between a two stroke mode and a four stroke mode in coordination with a transmission shift by adjusting a number of strokes performed by the engine per combustion cycle while shifting the transmission between different gear ratios. Under select conditions, the number of strokes performed by the engine per combustion cycle may be reduced while shifting the transmission from a higher gear ratio to a lower gear ratio. Under other conditions, the number of strokes performed by the engine per combustion cycle may be increased while shifting the transmission from a lower gear ratio to a higher gear ratio.

Abstract: A multi-mode internal combustion engine is described. As one example, the engine may be transitioned between a two stroke mode and a four stroke mode in coordination with a transmission shift by adjusting a number of strokes performed by the engine per combustion cycle while shifting the transmission between different gear ratios. Under select conditions, the number of strokes performed by the engine per combustion cycle may be reduced while shifting the transmission from a higher gear ratio to a lower gear ratio. Under other conditions, the number of strokes performed by the engine per combustion cycle may be increased while shifting the transmission from a lower gear ratio to a higher gear ratio.

Abstract: An engine control system for managing lean operation of an internal combustion engine coupled to a lean NOx trap uses an indication of vehicle activity. A target amount of tailpipe emission per distance is adjusted based on the vehicle activity indication. Then, engine air-fuel ratio is controlled based on the adjusted target amount of tailpipe emission per distance. Also, the indication of vehicle activity is used to enable decontamination cycles of the lean NOx trap.

Abstract: A microprocessor-based controller is provided for generated heat in at various locations in an exhaust system of an engine by changing the heat generation technique utilized. In one case, some cylinder air-fuel ratios are modulated between stoichiometry and rich, while others are modulated between stoichiometry and lean. Another approach operates some cylinder lean, while others are modulated between a first rich, and a second, less rich, value. Further, compensation based on engine airflow is also provided. Finally, various methods are described for temperature control and for controlling modulation of air-fuel ratio.

Abstract: An engine diagnostic system for use with an internal combustion engine coupled to a lean NOx trap with a NOx sensor coupled downstream of the trap. Degradation of the NOx sensor is determined by estimated NOx exiting the trap based on engine out NOx and various other operating conditions. When the difference between the measured NOx and estimated NOx is greater than a predetermined value for a predetermined duration, degradation is indicated.

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 diagnostic system for use with an internal combustion engine coupled to a lean NOx trap with a sensor coupled downstream of the trap. The sensor provides two output signals, one indicative of an air-fuel ratio and the second indicative of a NOx concentration. Construction of the sensor insists that proper indication of NOx concentration is dependent upon proper operation of the first output signal. Degradation of the NOx concentration signal is determined when the first output signal has degraded.

Abstract: A more precise method for determining the oxygen storage capacity of an exhaust gas aftertreatment device is presented. The most accurate capacity estimate is obtained while the engine is idling or during low load operation. The capacity is determined by integrating the output of an oxygen sensor located downstream of the device during a period of time that it takes to store more than a predetermined amount of oxygen in the device. The overall LNT efficiency can then be inferred from its oxygen storage capacity. This method allows for improved emission control and fuel economy.

Abstract: Hybrid vehicles and other vehicles with one or more torque producing devices operate more effectively with proper resolution of torque requests. In one aspect of the present invention, a plurality of vehicle force and torque requests are resolved at different levels depending on the vehicle architecture. In another aspect of the present invention, torque requests are resolved into base requests and fast requests depending upon response times of torque devices satisfying these requests.

Abstract: A computer controller is described for disabling fuel injection into cylinder groups of an engine. The system controls engine output a reduced engine torques without reducing engine air amounts below an engine misfire amount by reducing the number of cylinders carrying out combustion. Engine airflow is controlled to maintain accurate torque at requested levels throughout engine operating ranges.

Abstract: Method and electronic control system using a unique driver demand (calibration) table stored in system memory to provide torque output values specific to a 4×4 mode of operation of the vehicle drive unit. For example, the torque output of the electronic control system for a 4×4 low mode of operation is controlled using a unique calibration table stored in system memory for 4×4 low mode of operation, while the torque output of the electronic control system for other modes of operation is controlled using one or more different, other calibration tables stored in system memory.

Abstract: An engine diagnostic system for use with an internal combustion engine coupled to a lean NOx trap with a NOx sensor coupled downstream of the trap is disclosed. Degradation of the NOx sensor is determined by estimating NOx exiting the trap based on engine out NOx and various other operating conditions. When the difference between the measured NOx and estimated NOx is greater than a predetermined value for a predetermined duration, degradation is indicated.

Abstract: An engine diagnostic system for use with an internal combustion engine coupled to a lean NOx trap with a sensor coupled downstream of the trap. The sensor provides two output signals, one indicative of an air-fuel ratio and the second indicative of a NOx concentration. Construction of the sensor insists that proper indication of NOx concentration is dependent upon proper operation of the first output signal. Degradation of the NOx concentration signal is determined when the first output signal has degraded.

Abstract: An engine diagnostic system for use with an internal combustion engine coupled to a lean NOx trap with a NOx sensor coupled downstream of the trap. Degradation of the NOx sensor is determined by estimated NOx exiting the trap based on engine out NOx and various other operating conditions. When the difference between the measured NOx and estimated NOx is greater than a predetermined value for a predetermined duration, degradation is indicated.

Abstract: A microprocessor-based controller is provided for generated heat in at various locations in an exhaust system of an engine by changing the heat generation technique utilized. In one case, some cylinder air-fuel ratios are modulated between stoichiometry and rich, while others are modulated between stoichiometry and lean. Another approach operates some cylinder lean, while others are modulated between a first rich, and a second, less rich, value. Further, compensation based on engine airflow is also provided. Finally, various methods are described for temperature control and for controlling modulation of air-fuel ratio.

Abstract: A computer controller is described for disabling fuel injection into cylinder groups of an engine. The system controls engine output a reduced engine torques without reducing engine air amounts below an engine misfire amount by reducing the number of cylinders carrying out combustion. Engine airflow is controlled to maintain accurate torque at requested levels throughout engine operating ranges.

Abstract: A method is described for controlling fuel vapor purging and adaptive learning in a lean burn engine system. Fuel vapor purging is carried out during lean operating conditions to minimize impact on vehicle emissions, while adaptive learning is carried out during near stoichiometric conditions (oscillations around stoichiometry). This allows faster fuel vapor purging and additional adaptive learning opportunity.

Abstract: A method is described for controlling fuel vapor purging and adaptive learning in a lean burn engine system. Fuel vapor purging is carried out during lean operating conditions to minimize impact on vehicle emissions, while adaptive learning is carried out during near stoichiometric conditions (oscillations around stoichiometry). This allows faster fuel vapor purging and additional adaptive learning opportunity.

Abstract: A microprocessor-based controller is provided for generated heat in at various locations in an exhaust system of an engine by changing the heat generation technique utilized. In one case, some cylinder air-fuel ratios are modulated between stoichiometry and rich, while others are modulated between stoichiometry and lean. Another approach operates some cylinder lean, while others are modulated between a first rich, and a second, less rich, value. Further, compensation based on engine airflow is also provided. Finally, various methods are described for temperature control and for controlling modulation of air-fuel ratio.

Abstract: A method and apparatus for controlling the operation of a “lean-burn” internal combustion engine in cooperation with an exhaust gas purification system having an emissions control device capable of alternatively storing and releasing NOx when exposed to exhaust gases that are lean and rich of stoichiometry, respectively, determines a performance impact, such as a fuel-economy benefit, of operating the engine at a selected lean or rich operating condition. The method and apparatus then enable the selected operating condition as long as such enabled operation provides further performance benefits.