Abstract: A powertrain controller and a method for calculating feed-forward torque for use by the controller, including a powertrain control module that calculates current and leading indicators of engine torque. The leading indicator of engine torque is used by a multiple-ratio transmission in the powertrain to control transmission line pressure for actuating pressure-operated clutches and brakes for the gearing. The same information that is used for establishing transmission line pressure control is used for commanding an electronic throttle actuator for the engine. The electronic throttle actuator responds to an engine torque request generated by the powertrain controller to achieve a relatively instantaneous response of the engine throttle to a driver command for engine torque.

Abstract: Systems and methods for determining engine oil temperature without an oil temperature sensor infer the oil temperature at engine start based on the calculated temperature at power down and various other parameters which may include engine coolant temperature, soak time, ambient temperature, and whether an engine block heater has been used. The invention provides a more accurate determination of engine oil temperature to allow more precise engine control particularly during cranking and during the first few minutes of engine operation.

Abstract: A method is presented for correcting estimates of engine output torque and accessory load torque. Engine output torque estimates are corrected when the accessory is disengaged from the engine. Accessory load torque is learned, or corrected, when the accessory is engaged to the engine. In one example, these corrections are made when engine output torque is known to be substantially zero from torque converter speed ratio or from the timing of the overrunning clutch engagement. This information is then used to control engine output torque to improve drive feel and vehicle performance.

Abstract: A torque based cam timing system and method for an engine having dual independent camshafts is disclosed that includes a first set of ROM based calibration tables containing values for intake valve closing and valve overlap that provide best fuel economy and emissions over the operating range of engine speed and engine indicated torque and a second set of ROM based calibration tables containing values for intake valve closing and valve overlap for optimal power over the operating range of engine speed. A power index value that indicates the change in driver desire from fuel economy to power, is used to interpolate over the range of values in the first set of tables to the values in the second set of tables to calculate values of intake valve closing and valve overlap that are optimal for all altitudes.

Abstract: A system and method for controlling a multi-cylinder internal combustion engine include determining a currently available maximum torque, determining a driver demanded torque based on a current accelerator pedal position and reference ambient conditions, and controlling the engine to deliver the lesser of the driver demanded torque corresponding to the reference ambient conditions and a calibratable percentage of the currently available maximum torque corresponding to the current ambient conditions. A similar torque is provided at high altitudes as that provided at sea level for a given low pedal position while smoothly blending into the currently available peak torque.

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, optimizes vehicle fuel economy while complying with emissions standards by prohibiting lean engine operation only when tailpipe emissions, calculated in terms of grams of an exhaust gas constituent per vehicle mile traveled, exceeds a permissible threshold value. The threshold value is preferably itself periodically determined based upon a detected or determined level of vehicle activity, such that vehicle activity characterized by greater transient engine operation prescribes a relatively lower level of permissible vehicle emissions.

Abstract: A method and system for controlling the operation of “lean-burn” internal combustion engines, wherein initial values for measures representing current levels of NOx and SOx stored in an emissions control device, such as a lean NOx trap, upon vehicle start-up are determined based at least in part upon values for the measures immediately preceding engine shut-off. Such initial values obviate the need for performing a purge event immediately upon engine start-up in appropriate circumstances, such as a brief engine shut-down, whereby the fuel economy penalty associated with such an initial purge event is avoided.

Abstract: A method for updating an air flow ratio of a current engine load to a maximum engine load includes calculating an approximate air flow ratio based only on throttle position changes. The approximate air flow ratio is calculated by modifying a normal, conventionally calculated air flow ratio based on a difference between two throttle position loads. The throttle position loads are ratios between sampled throttle positions and a reference throttle position. By approximating the air flow ratio rather than conducting an exact calculation, the invention method can update the air flow ratio to reflect changes in throttle position without adding significant chronometric burden.

Abstract: A method and system for diagnosing catalyst operation in an internal combustion engine having a two-bank, three EGO sensor structure includes determining the ratio of the arc length between the post-catalyst EGO sensor signal and the arc length of a pre-catalyst EGO sensor signal over a selected time period. If the exhaust bank is a one-sensor bank having only a post-catalyst EGO sensor and no pre-catalyst EGO sensor, the system uses the arc length from the pre-catalyst EGO sensor in the two-sensor bank to calculate the arc length ratio, thereby allowing calculation of two arc length ratios without two matched pairs of EGO sensors. The ratio indicates the efficiency of the catalyst and may be compared with calibratable or experimentally-determined thresholds to monitor converter efficiency over time.

Abstract: A method and system for controlling the air/fuel ratio in an internal combustion engine having first and second groups of cylinders coupled to first and second exhaust banks, respectively. The first exhaust bank includes a catalyst and at least a pre-catalyst oxygen sensor. The second exhaust bank includes a catalyst and no more than one post-catalyst oxygen sensor. The oxygen sensors monitor the oxygen content of the exhaust gases in their corresponding exhaust banks and provide feedback signals to a controller. The controller uses the feedback signal from the pre-catalyst oxygen sensor (in the first bank) to calculate desired A/F values in the first group of cylinders. The controller uses both the feedback signal from the pre-catalyst oxygen sensor (in the first bank) and the feedback signal from the post-catalyst oxygen sensor (in the second bank) to calculate desired A/F values for the second group of cylinders.

Abstract: A method for monitoring an electronically controlled drive unit of a vehicle uses actual vehicle acceleration and a preselected vehicle acceleration. Actual acceleration is determined from any of an acceleration sensor or vehicle speed sensors. When actual acceleration is greater than the preselected acceleration, a reaction is initiated to reduce vehicle acceleration.

Abstract: A method for controlling cycling of an air conditioning compressor coupled to an internal combustion engine interrupts normal cycling based on operation conditions. In addition, normal engaged and disengaged cycling durations are adaptively estimated in real-time. The method of the present invention achieves improved fuel economy and improved drive feel. As an example, improved fuel economy is achieved by engaging the compressor during braking or when the engine is being driven by the vehicle. As another example, improved drive feel is achieved by engaging the compressor during transient conditions when drive feel is unaffected.

Abstract: A method for monitoring an electronically controlled drive unit of a vehicle uses actual vehicle acceleration and a preselected vehicle acceleration. Actual acceleration is determined from any of an acceleration sensor or vehicle speed sensors. When actual acceleration is greater than the preselected acceleration, a reaction is initiated to reduce vehicle acceleration. A method for controlling vehicle acceleration is also disclosed where desired acceleration is determine from either the operator command or a cruise control system.

Abstract: A method and system for controlling the air/fuel ratio in an internal combustion engine having a first group of cylinders and a second group of cylinders. The first group of cylinders is coupled to a catalyst and at least one oxygen sensor, which provides a first feedback signal. The second group of cylinders is coupled to a catalyst and a post-catalyst oxygen sensor, which provides a second feedback signal. A controller uses the first and second feedback signals to calculate a short-term air/fuel bias value for the second group of cylinders. The controller also calculates a new long-term air/fuel bias value corresponding to the current engine speed and engine. The new long-term air/fuel bias value is based on a previously-calculated long-term air/fuel bias value calculated for the same engine load and speed. A total air/fuel bias value is calculated based on the short-term air/fuel bias value and the long-term air/fuel bias value. The new long-term air/fuel bias value is stored for future calculations.

Abstract: An electronic engine controller controls the catalytic converter temperature by generating a desired rich air/fuel ratio that will maintain the catalytic converter at a predetermined temperature. The actual air/fuel ratio is ramped to the desired air/fuel ratio at a first rate when the catalytic converter temperature is greater than a first predetermined temperature. The actual air/fuel ratio is ramped to the desired air/fuel ratio at a second rate when the catalytic converter temperature is greater than a second predetermined temperature but less than the first predetermined temperature.

Abstract: An engine control method for improving air-fuel ratio control controls airflow when fuel injector limits are reached. The method includes a transient fuel model to calculate a required fuel injection amount based on actual cylinder air charge and feedback from an exhaust sensor. When the required fuel injection amount is outside an operable range, for example, less than zero, airflow is controlled to prevent deviations of exhaust air-fuel ratio. Otherwise, airflow is controlled to provide a desired engine torque. Alternatively, a minimum allowable airflow is determined based on a minimum achievable fuel flow. Then, airflow is prevented from falling below this minimum allowable airflow. The method is particularly useful in preventing rich excursions during rapid decreases in desired engine torque, such as during a driver tip-out.

Abstract: An EGR system monitor combines an inferred manifold absolute pressure based on measured mass air flow with a measured manifold absolute pressure to obtain a more complete system response during a test procedure involving the opening and closing of the EGR valve.

Abstract: A method is presented for correcting estimates of engine output torque and accessory load torque. Engine output torque estimates are corrected when the accessory is disengaged from the engine. Accessory load torque is learned, or corrected, when the accessory is engaged to the engine. In one example, these corrections are made when engine output torque is known to be substantially zero from torque converter speed ratio or from the timing of the overrunning clutch engagement. This information is then used to control engine output torque to improve drive feel and vehicle performance.

Abstract: A control method and system is described for a spark ignited, four-stroke engine having multiple combustion chambers, each coupled to at least one intake and one exhaust valve, a fuel injection system for injecting fuel directly into each combustion chamber, and an electronically controlled throttle for throttling air inducted through an intake manifold into the combustion chambers. Additional fuel is injected during the exhaust valve overlap. This additional fuel is drawn from the combustion chamber into the intake manifold and subsequently inducted back into the combustion chamber past the intake valve, thereby cleaning carbon deposits from the intake valve and the surrounding surfaces.

Abstract: A speed control method for vehicles having an internal combustion engine smoothly controls engine torque to control vehicle speed. Torque is controlled via airflow in a first torque control range. Torque is controlled via a coordination of air/fuel ratio, ignition timing, and cylinder deactivation is a second torque control range. The torque range is selected based on the required airflow to deliver the required torque. If the required airflow is less than a lower allowable value, then the airflow is fixed at this lower allowable value and the second range is selected. Otherwise, the first range is selected.