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 operating condition, with due consideration of the periodic rich operating condition necessary to release stored NOx from the device. The method and apparatus further determine a measure representative of the instantaneous NOx-storing efficiency of the device. The method and apparatus enable the selected lean operating condition as long as the determined performance impact and the determined device efficiency are each above respective predetermined minimum levels.

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: An engine control system for managing lean NOx trap decontamination uses associated fuel economy impacts to determine when decontamination is enabled. In particular, a maximum achievable benefit provided by lean operation with a decontaminated NOx trap, a present fuel economy benefit being provided by lean operation, and a fuel economy penalty for performing decontamination are used. When a resulting benefit is greater than a penalty, decontamination is enabled.

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: An engine control system for managing lean NOx trap decontamination uses associated fuel economy impacts to determine when decontamination is enabled. In particular, a maximum achievable benefit provided by lean operation with a decontaminated NOx trap, a present fuel economy benefit being provided by lean operation, and a fuel economy penalty for performing decontamination are used. When a resulting benefit is greater than a penalty, decontamination is enabled.

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: 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 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: 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 and apparatus for determining the capacity of a trap to store NOx based on the change in oxygen storage in the trap occurring as a result of sulfation of the trap.

Abstract: A misfire monitoring method and system employ an indicated mean effective pressure (IMEP) parameter for misfire monitoring of an internal combustion engine of a vehicle. The method and system include determining displacement and torque of the engine. An indicated mean effective pressure (IMEP) parameter is then calculated for the engine. The indicated mean effective pressure (IMEP) parameter is engine torque divided by engine displacement. A misfire monitor monitors the indicated mean effective pressure (IMEP) parameter to detect misfire. The method and system include determining maximum indicated mean effective pressure (IMEP_MAX) parameter for the engine. A normalized indicated mean effective pressure (IMEP_LOAD) parameter for the engine is then calculated. The normalized indicated mean effective pressure (IMEP_LOAD) parameter is the indicated mean effective pressure (IMEP) parameter divided by the maximum indicated mean effective pressure (IMEP_MAX) parameter.

Abstract: A method is presented for improved interaction between driver demand, cruise control system and traction control system in an internal combustion vehicle. Desired engine output torque is adjusted based on the above inputs and vehicle operating conditions. This method improves drive feel and customer satisfaction with vehicle performance.

Abstract: A method is presented for improved interaction between driver demand, cruise control system and traction control system in an internal combustion vehicle. Desired engine output torque is adjusted based on the above inputs and vehicle operating conditions. This method improves drive feel and customer satisfaction with vehicle performance.

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.

Abstract: A method and apparatus for controlling the operation of a “lean-burn” internal combustion engine in cooperation with an emissions control device capable of alternatively storing and releasing an exhaust gas constituent, such as oxygen, when exposed to exhaust gases that are lean and rich of stoichiometry, respectively, determines an ability of the device only when the engine is operating at a relatively-low mass air flow rate.

Abstract: An air/fuel control method for an engine including a NOx sensor in operative relationship to a catalytic converter. The method comprises the steps of providing a base fuel signal related to a quantity of air inducted into the engine and generating a bias signal for biasing the base fuel signal towards a leaner air/fuel ratio. The output of the NOx sensor is monitored to detect a predetermined exhaust gas NOx value representing a predefined NOx conversion efficiency. The base fuel signal is then modified as a function of the bias signal corresponding to the predetermined exhaust gas NOx value to maintain the catalytic converter within a desired efficiency range. In one aspect of the invention, the process of detecting the edge of the NOx conversion efficiency window is executed at predetermined time periods measured by the distance the vehicle traveled, or the elapsed time since last base fuel value modification.

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 control system for managing lean NOx trap decontamination uses associated fuel economy impacts to determine when decontamination is enabled. In particular, a maximum achievable benefit provided by lean operation with a decontaminated NOx trap, a present fuel economy benefit being provided by lean operation, and a fuel economy penalty for performing decontamination are used. When a resulting benefit is greater than a penalty, decontamination is enabled.

Abstract: An engine control system of an internal combustion engine coupled to a NOx trap uses a measured air-fuel ratio downstream of the NOx trap to control engine air-fuel ratio. The measured air-fuel is only used for feedback when it indicates a value away from stoichiometry. Thus, NOx and oxygen storage effects that cause inlet air-fuel ratio to be different from exit air-fuel ratio do not cause degraded feedback air-fuel ratio control.