Abstract: A system and method for controlling an internal combustion engine to improve air/fuel ratio control using a feed-forward observer-based control strategy include estimating current and future airflow actuator positions, determining corresponding mass airflow values, and determining a future in-cylinder air charge based on a difference between the current and future mass airflow values. In one embodiment, the difference between current and future mass airflow estimates is used as a feed-forward term and combined with a sensed or measured value generated by a mass airflow sensor prior to being processed using a manifold filling model to predict the future cylinder air charge.

Abstract: A method for measuring flow through an orifice using an upstream gauge pressure sensor and a downstream absolute pressure sensor determines atmospheric pressure when flow through the orifice is substantially zero, or less than a predetermined value. Then, this estimate, along with the upstream and downstream pressure sensors are used to measure flow through the orifice.

Abstract: The invention relates to a new method and system for optimizing the efficiency of an automotive catalytic converter by adjusting the engine air/fuel ratio based on estimates of the actual amount of oxidants stored in the catalyst. To do so, the invented system estimates an amount of oxidants stored in the catalyst. The amount of oxidants stored is estimated by determining an amount of oxidants that are available for storage by the catalyst or that are needed to oxidize hydrocarbons being produced by the engine. Based thereon, a change in oxidant storage in the catalyst is calculated. The estimate of the amount of oxidants that are available for storage by the catalyst or that are needed to oxidize hydrocarbons is adjusted based on a feedback parameter.

Abstract: The invention relates to a new method and system for optimizing the efficiency of an automotive catalytic converter. The invention comprises adjusting an air/fuel ratio in the cylinders of an internal combustion engine to maintain the amount of oxidants stored in the catalyst at or near an oxidant target value. The oxidant target value is either a pre-determined constant value or a dynamically-determined value that is calculated based on engine operating conditions. The air/fuel ratio in the cylinders is adjusted based on the magnitude of the difference between the actual oxidant amount and the target oxidant amount to prevent NOx and hydrocarbon breakthrough.

Abstract: An air/fuel control system and method for controlling an air/fuel ratio entering an engine are disclosed. The system comprises a controller and two sensors. In operation, a first feedback loop is created around the engine to control the oxygen concentration in the exhaust gas. A second feedback loop is created around the engine and emission control device to adjust the air/fuel ratio. An emission control device model is used to modify the air/fuel ratio adjustment. A learned integral bias table, responsive to engine speed and engine load, is provided in the second feedback loop. Entries in the learned integral bias table are modified, one at a time, based upon integrated measurements of the downstream oxygen concentration made while the engine and catalyst are under stable operating conditions.

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.

Abstract: A method and system for controlling the operation of “lean-burn” internal combustion engines determines a current rate of vehicle NOx emissions, and determines a threshold value for permissible vehicle NOx emissions based on at least one current value for the intake air-fuel ratio, engine speed, engine load (e.g., brake torque, manifold air pressure, or throttle position), and/or vehicle speed. A differential NOx emissions rate is calculated as the difference between the current rate and the threshold rate, and the differential rate is accumulated over time to obtain a differential measure representing the amount by which cumulative NOx emissions have fallen below permissible levels therefor. Lean engine operation is disabled when the differential NOx emissions measure exceeds a predetermined excess vehicle NOx emission value. In this manner, vehicle NOx emissions are favorably controlled even when the engine is operated “off-cycle,” i.e.

Abstract: A system and method for controlling a powertrain including an automatic transmission include determining a desired wheel torque, determining engine speed, determining turbine speed, determining a selected gear and associated selected gear ratio, determining a transmission spin loss based on a first function of the turbine speed and the selected gear, determining a transmission torque proportional loss based on a second function of the turbine speed and the selected gear, determining a desired engine torque based on the transmission spin loss, the transmission torque proportional loss, and the selected gear ratio, and controlling the powertrain using the desired engine torque such that actual wheel torque approaches the desired wheel torque. A transmission pump loss may also be determined based on line pressure and engine speed.

Abstract: A system and a method for controlling engine torque in an internal combustion with a randomly operable intake valve and a selectable intake valve is disclosed in which torque is controlled via a throttle valve when the randomly operable intake valve is deactivated and via intake valve closing time of the randomly operable intake valve when the selectable intake valve is deactivated.

Abstract: A method for estimating pressure surround an engine uses a gauge pressure sensor upstream of an orifice and an absolute pressure sensor downstream of the orifice. In particular, atmospheric pressure can be determined when flow through the orifice is below a predetermined threshold.

Abstract: A method is described for controlling a powertrain of a vehicle. In particular, the method attempts to minimize transmission gear separation, or “clunk”. Under some circumstances, it is determined whether torque converter output speed has become greater than torque converter input speed while the torque converter was unlocked. Such a situation represents a change from positive powertrain output to negative powertrain output. If such a situation has occurred, under certain circumstances, the torque converter is then locked.

Abstract: A vehicle and engine control system controls engine torque to maintain positive torque at a transmission input to minimize the transmission gears from separating. By maintaining a positive engine torque, operation of the transmission in or through the zero torque, or lash, zone, is minimized. This minimizes poor vehicle driveability that would otherwise result from operation in the lash zone. The control systems uses closed loop control based on a desired and actual turbine speed ratio, or slip ratio, to provide positive torque to the transmission.

Abstract: An engine control system of an internal combustion engine coupled to a NOx trap uses a integrated difference between NOx exiting the trap and NOx entering the trap to determine NOx storage capacity. NOx exiting the trap is measured by a NOx sensor downstream of the trap. NOx entering the trap is determined based on engine operating conditions. The values are integrated until the ratio of NOx exiting to NOx entering reaches a predetermined threshold.

Abstract: A method is presented for controlling fuel tank pressure in an internal combustion engine. The engine, the fuel tank and the carbon canister are connected in a three-way connection. The engine can be selectively isolated by a purge control valve, and the fuel tank can be selectively isolated by a fuel tank control valve. The operation of both valves is coordinated by an electronic engine controller. By isolating the fuel tank during the carbon canister purge, better estimate of the fuel fraction flowing into the engine can be achieved, thereby improving fuel economy.

Abstract: A connector assembly for connecting a catalytic converter assembly to a muffler and tailpipe assembly includes first and second flexible portions, and a middle portion disposed between the flexible portions. The middle portion includes a catalyst element for modifying exhaust gases passing from the catalyst assembly to the muffler and tailpipe assembly.

Abstract: A computer readable storage medium having stored data representing instructions for controlling a spark ignited direct injection internal combustion engine having a plurality of cylinders operable in at least homogeneous and stratified modes, includes instructions for determining a desired value for an engine operating parameter based on current engine operating conditions wherein the desired value results in scheduling of an air/fuel ratio between homogeneous range and stratified range of allowable air/fuel ratios, instructions for operating a first portion of the cylinders in the homogenous operating mode, and instructions for operating a second portion of the cylinders in the stratified operating mode such that a combined air/fuel ratio associated with the first and second portions of the cylinders approaches the scheduled air/fuel ratio.

Abstract: A catalytic monitoring method for an engine having two engine banks of which each coupled to one of two catalytic converters using first and second exhaust gas oxygen sensors respectively, upstream and downstream of one catalytic converter. Third and fourth exhaust gas oxygen sensors are respectively coupled upstream and downstream of the other catalytic converter. Switch ratios are determined for each of the engine banks based on the switching ratios of each upstream and downstream pair of exhaust gas oxygen sensors. A combination of the switch ratios is used to determine overall catalytic converter system performance.

Abstract: A method is presented for determining whether a fuel sensor in a vehicle having a fuel tank, a fuel delivery system, electronic engine controller, air flow and air/fuel ratio sensors and an instrument panel is stuck in-range. First, the electronic engine controller from the information provided by the above sensors estimates an amount of fuel consumed. The estimate is then compared to the actual fuel consumed data from the fuel sensor. If the difference between the actual and estimated amounts exceeds a small predetermined constant, the determination is made that the fuel sensor is stuck in-range and a diagnostic code is sent to the instrument panel and stored for use by a service technician.

Abstract: A computer readable storage medium having instructions for controlling an engine includes instructions for determining a desired engine brake torque and modifying the desired engine brake torque based on current engine operating conditions to determine a requested engine brake torque prior to determination of control parameters, including at least one of an airflow and a fuel quantity, to effect the requested engine brake torque. Preferably, the desired engine brake torque is modified by combining the desired engine brake torque with an idle speed torque to generate a first intermediate torque, comparing the first intermediate torque to an actual engine brake torque to generate a second intermediate torque, generating a feedback correction torque based on the second intermediate torque, and combining the first intermediate torque, the feedback correction torque, and a third intermediate torque to determine the requested engine brake torque.

Abstract: A method is presented for correcting the output of the NOx sensor during a time period starting with the end of the NOx purge cycle and ending when the amount of tail pipe O2 exceeds a preselected value. During that period, fuel is being deposited on the NOx sensor thus causing an incorrect reading. Proper amount of NOx generated during that time is calculated by assuming that the NOx level during the incorrect reading is equal to the NOx reading after the end of the incorrect reading, and multiplying that amount by total integrated air mass. This method helps avoid unnecessary NOx purges and improves fuel economy.