Abstract: A method of optimizing vehicle emissions during lean engine operation is disclosed wherein an emission control device receiving engine exhaust gases is filled with one or more constituent gases of the exhaust gas to a predetermined fraction of the device storage capacity, and is then completely emptied during a subsequent purge. As the device storage capacity is substantially reduced, as indicated by an actual fill time becoming equal to or less than a predetermined minimum fill time, a device regeneration cycle is performed to attempt to restore device capacity. A programmed computer controls the fill and purge times based on the amplitude of the voltage of a switching-type oxygen sensor and the time response of the sensor. The frequency of the purge, which ideally is directly related to the device capacity depletion rate, is controlled so that the device is not filled beyond its storage capacity limit.

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 method for improving NOx conversion efficiency of an exhaust gas after-treatment device is presented. The efficiency is improved by first maintaining the device at an operating temperature wherein improved storage of reductant is possible, and subsequently changing the temperature of the device to that where optimum NOx conversion efficiency is achieved, thereby obtaining and utilizing the conversion benefits of stored reductant.

Abstract: An improved method for estimating an input torque to the continuously variable transmission (CVT) is presented. The method includes calculating torque adaptation coefficients when the torque converter clutch is unlocked, and an accurate torque value can be obtained based on the torque converter characteristics. The adaptation coefficients are then used to correct the transmission torque estimate, which is then used to determine proper CVT clamping forces. This method improves fuel economy, transmission durability, and customer satisfaction.

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 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 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 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 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, vapor spikes into the engine are eliminated, thus preventing engine stalls. Also, canister durability is improved by continuously storing and purging vapors in opposite directions.

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 method is presented for improving performance of direct injection spark ignition internal combustion engines at high load conditions by increasing the degree of homogeneity of the air-fuel mixture during the intake stroke of the engine. The improved performance is achieved by adding a deflector designed to reduce intake air impinging upon the fuel spray and deflecting it to the intake side of the combustion chamber, thus facilitating better fuel circulation throughout the combustion chamber. This method improves engine performance at high load engine operating conditions.

Abstract: A method for controlling mode transitions, such as from stratified to homogeneous mode, in a direct injection engine adjusts a number of cylinders carrying out combustion to prevent engine torque disturbances. Cylinder activation is used when changes in cylinder air/fuel ratio cannot be compensated using ignition timing adjustments. In addition, the number of cylinders to activate is also determined and measures are taken if the number of cylinders determined are not available to be activated.

Abstract: A control method for an internal combustion engine has multiple cylinder groups with at least one control device positioned between an intake manifold and a cylinder group. The engine operates the cylinder groups at different air/fuel ratios and uses the control device to balance torque produced by the different cylinder groups. In one aspect of the invention, one cylinder group is operated rich and another cylinder group is operated lean thereby providing heat to an exhaust system located downstream of the engine.

Abstract: A method is presented for diagnosing an engine coolant temperature sensor and an engine thermostat. Engine coolant temperature is estimated based on engine operating conditions, such as engine speed, net engine torque, air flow, fuel-air ratio, exhaust gas temperature, etc., and a characteristic of the thermostat. The estimate is compared to the actual reading of the engine coolant temperature sensor in order to detect degradation in the performance of the sensor or the engine thermostat. If degradation is detected, the estimated engine coolant temperature can be used for various engine control strategies, such as electronic fuel injection, thereby improving vehicle performance, fuel efficiency, and emission control.

Abstract: A fuel vapor purging method controls fuel vapor purging during stratified operation. Several factors influence vapor purge control, including fuel vapor concentration in the cylinder and temperature of the emission control device. The fuel vapor passes through the cylinder unburned by maintaining the concentration within allowable limits. The unburned fuel vapor reacts exothermically in the emission control device thereby generating heat. To guarantee that the fuel vapor reacts in the first emission control device, the fuel vapor purge is restricted to a certain temperature range. To guarantee that the fuel vapor does not burn in the cylinder, the concentration is kept to a restricted value.

Abstract: A method is presented for controlling powertrain torque by minimizing the error between the actual powertrain torque (as read by the torque sensor) and the desired powertrain torque (as requested by the vehicle driver). Since torque sensors are known to drift under certain conditions, such as high ambient temperature, the output of the torque sensor is adjusted by an offset value. This offset value is determined by reading the torque sensor output when the speed ratio (engine speed/turbine speed) is substantially unity, and the net torque at the torque converter is substantially zero. This adjusted output is then filtered to avoid abrupt fluctuations in the powertrain torque, and used to improve powertrain control so that better drive feel and increased fuel economy can be achieved.

Abstract: A fuel vapor purging method controls fuel vapor purging during stratified operation. Several factors influence vapor purge control, including fuel vapor concentration in the cylinder and temperature of the emission control device. The fuel vapor passes through the cylinder unburned by maintaining the concentration within allowable limits. The unburned fuel vapor reacts exothermically in the emission control device thereby generating heat. To guarantee that the fuel vapor reacts in the first emission control device, the fuel vapor purge is restricted to a certain temperature range. To guarantee that the fuel vapor does not burn in the cylinder, the concentration is kept to a restricted value.

Abstract: A fuel vapor purging method controls fuel vapor purging during stratified operation. Several factors influence vapor purge control, including fuel vapor concentration in the cylinder and temperature of the emission control device. The fuel vapor passes through the cylinder unburned by maintaining the concentration within allowable limits. The unburned fuel vapor reacts exothermically in the emission control device thereby generating heat. To guarantee that the fuel vapor reacts in the first emission control device, the fuel vapor purge is restricted to a certain temperature range. To guarantee that the fuel vapor does not burn in the cylinder, the concentration is kept to a restricted value.

Abstract: A fuel vapor purging method controls fuel vapor purging during stratified operation. Several factors influence vapor purge control, including fuel vapor concentration in the cylinder and temperature of the emission control device. The fuel vapor passes through the cylinder unburned by maintaining the concentration within allowable limits. The unburned fuel vapor reacts exothermically in the emission control device thereby generating heat. To guarantee that the fuel vapor reacts in the first emission control device, the fuel vapor purge is restricted to a certain temperature range. To guarantee that the fuel vapor does not burn in the cylinder, the concentration is kept to a restricted value.

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.