Abstract: EGR system for an internal combustion engine (105) comprises an EGR valve (150) disposed in an EGR recirculation conduit (125) involves estimating exhaust gas temperature at an engine exhaust manifold. An exhaust gas temperature drop between the exhaust manifold and the EGR valve is estimated and a time constant is determined that models the exhaust gas temperature as a function of EGR mass flow rate so that exhaust gas temperature at the EGR valve can be estimated by adjusting the estimated exhaust gas temperature at the exhaust manifold by the exhaust gas temperature drop and the time constant.

Abstract: Method of estimating the total charge to cylinders (123) of an internal combustion (105) engine where the total charge comprises the sum of the air charge and the EGR charge. The total charge is estimated by determining a linear total charge versus MAP reference function at selected engine speeds and at a preselected reference (stored) barometric pressure, reference (stored) engine coolant temperature, and reference (stored) manifold air charge temperature and determining a current barometric pressure value, a current engine coolant temperature value, and a current intake manifold air charge temperature. An intercept of the total charge versus MAP reference function with an total charge axis (e.g.

Abstract: EGR system for an internal combustion engine comprises a stepper motor driven EGR valve (150) to control the rate of exhaust gas recirculation in the engine and an electronic controller (EEC 100) for determining a desired EGR percent mass flow rate as a function comprising a rotational speed value and an aircharge value of the engine, converting the EGR percent mass flow rate to an EGR mass flow rate value, adjusting the EGR mass flow rate value as a function of an exhaust gas temperature value and an absolute exhaust gas backpressure value using MAP values, determining a pressure ratio value across an EGR orifice (155) cooperating with the EGR valve, and determining a required number of motor steps as a function of the adjusted EGR mass flow rate value and the pressure ratio value to achieve the desired EGR percent mass flow rate.

Abstract: A system and method for controlling vehicle speed include mutually exclusive closed loop controllers for vehicle speed and acceleration which control vehicle speed by requesting an appropriate wheel torque. The system and method compute, in real time, the wheel torque required to maintain steady vehicle speed or steady acceleration depending on the particular mode of operation. The active closed loop controller acts upon vehicle speed or acceleration errors to output a desired torque request.

Abstract: An internal combustion engine includes an exhaust gas recirculation (EGR) mechanism for directing a controlled amount of exhaust gas generated by the engine from the exhaust manifold to an intake manifold of the engine. An electronic engine controller (EEC) controls the EGR by determining a base EGR rate as a function of a plurality of engine operating parameters. The base EGR rate is then modified by a multiplier to compensate the EGR rate for the effect of humidity. The multiplier represents the EGR percent change per grain of humidity deviation from a predetermined humidity level. The EEC further controls the borderline spark timing of the engine by determining a base spark timing as a function of a plurality of engine operating parameters at a predetermined humidity level. The spark rate is then modified by a multiplier to compensate the spark timing for the effect of humidity. The multiplier represents the degree of spark change per grains of humidity possible without incurring engine knock.

Abstract: An air control method for an internal combustion engine having air assist injectors and an electronically controlled throttle maximizes airflow through the injectors while maintaining a range of authority for the electronically controlled throttle. This method maximizes the benefits of fuel atomization while maintaining a desired engine speed in the presence of disturbances.

Abstract: The present invention provides a method of inferring the engine coolant temperature in cylinder head temperature sensor equipped vehicles including the steps of measuring the cylinder head temperature, calculating the engine coolant temperature from the measured cylinder head temperature as a function of at least one vehicle operational state, generating a signal for the calculated engine coolant temperature, and sending the generated signal to a display.

Abstract: A method and system for estimating the midbed temperature of a catalytic converter in an exhaust system of an internal combustion engine. A rate of change in the speed of the engine is sensed and an estimated number of misfires occurring in the engine over a predetermined number of cylinder filling events is determined based on the sensed rate of change in engine speed. An instantaneous temperature of exhaust gas at the exhaust flange is determined based on the estimated rate of misfires. An instantaneous temperature at the midbed point of the catalytic converter is then determined based on the instantaneous temperature of exhaust gas at the exhaust flange. The instantaneous temperature at the midbed point is compared to a predetermined temperature threshold and the estimate rate of misfires is compared to a predetermined misfire rate threshold.

Abstract: A method for accelerating the rotational speed of a crankshaft of an internal combustion engine having a plurality of cylinders each having a spark plug wherein a predetermined amount of delivered fuel is to be combusted at a firing time within each of the plurality of cylinders with each rotation of the camshaft or crankshaft based on an acceleration input made by an operator includes the step of receiving the accelerating input, measuring the rotational speed of the crankshaft, defining an expected engine speed based on the acceleration input, calculating a speed error as the rotational speed of the crankshaft less the expected engine speed, calculating engine acceleration and adjusting the predetermined amount of fuel delivered to be combusted in each of the plurality of cylinders to reduce the speed error when the speed error is a function of the instantaneous engine speed. The preferred embodiment is implemented using fuzzy logic.

Abstract: A method for estimating a temperature of a tip of an exhaust gas oxygen (EGO) sensor used with a heater in an electronic engine control for an engine having an exhaust system wherein the exhaust system includes a variable length exhaust pipe having a short path and a long path for transporting exhaust gas from the engine to the HEGO sensor and an exhaust valve positioned in the exhaust pipe for regulating the flow of exhaust gas between the short path and the long path utilizes control logic to determine whether the exhaust gas is flowing through the short path or the long path, determine a temperature of the unheated HEGO sensor based on the path of flow of the exhaust gas, and determine whether the heater is on. If the heater is not on, an amount of heat applied to the sensor is set to zero. If the heater is on, an increase in the temperature of the HEGO sensor is determined based on an amount of heat applied to the sensor.

Abstract: An engine control computer estimates the cumulative NO.sub.x storage in a NO.sub.x trap based on engine operating conditions and enters a NO.sub.x purge mode of operation when a maximum storage capacity limit, based on trap temperature, is exceeded. The purge mode is terminated when NO.sub.x storage level decreases below a minimum storage capacity limit. The rate of NO.sub.x dissipation is also based on trap temperature.

Abstract: A method for maintaining the rotational speed of a crankshaft of an internal combustion engine having a plurality of cylinders each having a spark plug wherein a predetermined amount of delivered fuel is to be combusted at a firing time within each of the plurality of cylinders with each rotation of the camshaft or crankshaft includes the step of operating the internal combustion engine, measuring the rotational speed of the crankshaft, defining an expected engine speed, calculating a speed error as the rotational speed of the crankshaft less the expected engine speed, and changing the predetermined amount of delivered fuel to be combusted in each of the plurality of cylinders to reduce the speed error. The preferred embodiment is implemented in fuzzy logic.

Abstract: A method and system for controlling the temperature of an exhaust system having a variable length exhaust pipe including a short path and a long path and an exhaust valve positioned in the exhaust pipe for regulating the flow of exhaust gas between the short path and the long path utilizes control logic for estimating a plurality of exhaust temperatures at various locations on the exhaust system. A plurality of maximum temperatures are also determined. The plurality of estimated exhaust temperatures are then compared with the plurality of maximum temperatures, and if a preselected number of the plurality of exhaust temperatures exceed the plurality of maximum temperatures, the exhaust valve is controlled so that the exhaust gas flows through the long path of the exhaust pipe so as to aid in cooling the exhaust gas.

Abstract: An engine control computer estimates the cumulative SO.sub.x stored in a NO.sub.x trap and enters a SO.sub.x purge mode of operation when a maximum storage capacity limit is exceeded. SO.sub.x accumulation is estimated based on fuel flow to the engine, A/F and trap temperature. The purge mode is terminated when the estimated SO.sub.x storage level drops below a minimum threshold level during the purging operation.

Abstract: A method and system for estimating the midbed temperature of a catalytic converter in an exhaust system of an internal combustion engine utilizes a sensor for a rotational speed of the engine and generating a corresponding speed signal. A control logic determines whether the exhaust gas is flowing through the short path or the long path, determines an instantaneous temperature of exhaust gas at a first point on the exhaust pipe based on the speed signal, and determines an instantaneous temperature at a midbed point of the catalytic converter based on the instantaneous temperature of exhaust gas at the first point on the exhaust pipe and which path the exhaust gas is flowing.

Abstract: A method and system for adaptive feedforward control of a fuel delivery system provides for adapting a normalized pressure input and a normalized flowrate input to a feedforward voltage look-up table. If low fuel flow and high manifold pressure are detected (104), then the normalized pressure input will be adapted based on a target fuel rail pressure and a pressure multiplier PMUL. If high fuel flow is detected (106), then the normalized flowrate input will be adapted based on a target flowrate and a flowrate multiplier FMUL. The present invention provides adaptive feedforward control without the need for the look-up table to be stored in a keep-alive memory (KAM).

Abstract: A control method is described for an engine having a throttle body coupled to the engine intake manifold and a bypass air passageway coupled to the throttle body via an electronically controllable bypass valve. A single measurement of air inducted through both the throttle body and the bypass air passageway is provided by an air flow meter. Fuel is delivered to the intake manifold in relation to the single air measurement. An air flow correction value is generated from a functional relationship between engine torque and air/fuel ratio during lean air/fuel operating conditions. Air flow through the bypass passageway is increased by the air flow correction value to compensate for engine torque loss resulting from such lean operation.

Abstract: A method (42) is disclosed for detecting the usage of a heater (31) in a block (30) of an internal combustion engine (11). The method (42) uses temperature measurements of the engine coolant and any ambient air used to create the air/fuel mixture. Based on the difference between the temperatures, the temperatures are weighted and added to create a temperature variable. The temperature variable is used by the electronic engine control module (34) to create an air/fuel mixture which will allow the internal combustion engine (11) to start smoothly. The method (42) operates on this modified temperature; i.e., the temperature variable, which is not the temperature of the engine coolant, nor the ambient air, and allows for the stoichiometric balance of the air/fuel mixture to be modified to optimize performance of the internal combustion engine (11) during a cold start in cold weather with warm engine coolant.

Abstract: A managed fuel air mode control system is provided which operates in an open loop lean mode of operation whenever open loop enable criteria is met. During the open loop lean mode of operation, a rich A/F purge mode of operation is dictated when a NO.sub.x trap is determined to be full. After purging the trap, engine operation returns to stoichiometric and either enters a closed loop learning operation or returns to lean operation depending upon the time that has passed since the last learning operation. During the learning operation, an adaptive control algorithm learns or updates a long term correction factor that is used during the open loop lean A/F mode of operation. Also during open loop operation, the amount of SO.sub.x accumulated in the trap is calculated and the open loop mode is terminated when the amount of SO.sub.x exceed a threshold.

Abstract: An engine control computer estimates NO.sub.x trap temperature based on an estimated midbed temperature of a three-way catalytic converter located upstream from the trap and the effect on NO.sub.x trap temperature of introducing air into the exhaust upstream of the trap during purging of the trap.