Abstract: A system for electronically actuating valves in an engine. The system includes a first voltage source, a second voltage source, and plural valve actuator subsystems coupled between the first voltage source and the second voltage source. Each valve actuator subsystem has a valve actuator and a switch. One of the actuator subsystems is configured so that current flows from the first voltage source through the valve actuator of the subsystem when the switch is in a first position, and when the switch is in a second position, current is permitted to flow from the valve actuator toward the second voltage source. Another of the valve actuator subsystems is configured so that current flows from the second voltage source through the valve actuator of the subsystem when the switch is in a first position, and when the switch is in a second position, current is permitted to flow from the valve actuator toward the first voltage source.

Abstract: A valve control and diagnostic system uses physical stops to determine whether a connection between the valve motor and the valves has become degraded. The method can detect degradation in both the opening and closing direction, as well as in multi-valve systems, such as used on internal combustion engines.

Abstract: An exhaust gas recirculation system directs exhaust gasses from an exhaust manifold to an intake manifold of an internal combustion engine. The exhaust gasses travel from the exhaust manifold, first passing through a flow control valve and then through a measuring orifice before entering the intake manifold. Pressure upstream of the orifice is used, along with correction pressure downstream of the orifice, to measure and control exhaust gas flow. Further, manifold pressure is determined from downstream pressure and the used along with the measured exhaust gas flow to calculated a cylinder air charge amount.

Abstract: A method is disclosed for controlling operation of an engine coupled to an exhaust treatment catalyst. Under predetermined conditions, the method operates an engine with a first group of cylinders combusting a lean air/fuel mixture and a second group of cylinders pumping air only (i.e., without fuel injection). In addition, the engine control method also provides the following features in combination with the above-described split air/lean mode: idle speed control, sensor diagnostics, air/fuel ratio control, adaptive learning, fuel vapor purging, catalyst temperature estimation, default operation, and exhaust gas and emission control device temperature control. In addition, the engine control method also changes to combusting in all cylinders under preselected operating conditions such as fuel vapor purging, manifold vacuum control, and purging of stored oxidants in an emission control device.

Abstract: A direct injection engine is coupled to a vacuum brake booster wherein vacuum created from engine pumping is used to supplement driver braking force. The brake booster is coupled through a check valve to the engine intake manifold. A method is disclosed for estimating pressure in the brake booster based on operating conditions. A method is also disclosed for estimating operating parameters based on measured brake booster pressure. Further, a method is disclosed for diagnosing degradation, or monitoring, a brake booster pressure sensor based on operating conditions. In addition, a method is disclosed for diagnosing degradation in other vehicle and engine sensors based on measured brake booster pressure.

Abstract: An engine diagnostic system for use with an internal combustion engine coupled to a lean NOx trap with a NOx sensor coupled downstream of the trap is disclosed. Degradation of the NOx sensor is determined by estimating NOx exiting the trap based on engine out NOx and various other operating conditions. When the difference between the measured NOx and estimated NOx is greater than a predetermined value for a predetermined duration, degradation is indicated.

Abstract: A microprocessor-based controller is provided for generated heat in at various locations in an exhaust system of an engine by changing the heat generation technique utilized. In one case, some cylinder air-fuel ratios are modulated between stoichiometry and rich, while others are modulated between stoichiometry and lean. Another approach operates some cylinder lean, while others are modulated between a first rich, and a second, less rich, value. Further, compensation based on engine airflow is also provided. Finally, various methods are described for temperature control and for controlling modulation of air-fuel ratio.

Abstract: A method is described for estimating cylinder charge using either the throttle position or mass air flow sensor. The method saves calibration and development expenses by using the same manifold filling model approach regardless of which sensor, or combination of sensors, is used.

Abstract: A method is presented for idle speed control of a lean burn spark ignition internal combustion engine using a fuel-based control strategy. In particular, the idle speed control strategy involves using a combination of fuel quantity or timing and ignition timing to achieve desired engine speed or torque while maintaining the air/fuel ratio more lean than prior art systems. Depending on engine operating conditions, the fuel quantity or timing is adjusted to give a more rich air/fuel ratio in order to respond to an engine speed or torque demand increase. Additionally, due to operation close to the lean misfire limit, the spark ignition timing is adjusted away from MBT in response to an engine speed or torque demand decrease. The advantages of this fuel based control system include better fuel economy as well as fast engine response time due to the use of fuel quantity or timing and ignition timing to control engine output.

Abstract: A system is described for determining degradation of an exhaust gas recirculation system of an internal combustion engine. This method utilizes a combination of parameters to accurately determine degradation of the exhaust gas recirculation system. For example, the system utilizes changes in intake manifold pressure, changes in idle speed control operation, changes in ignition timing, and fueling changes to accurately determine operation of the exhaust gas recirculation system.

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: An electromagnetically operated valve assembly (28) has a first solenoid (58) and a second solenoid (60). An armature (56) having a valve stem (54) coupled thereto is positioned between the first solenoid (58) and second solenoid (60). A controller (12) is coupled to the first solenoid (58), the second solenoid (60). A current sensor (49) is coupled to the first solenoid and generated a signal corresponding to the induced current in the first solenoid. The controller (12) changes a voltage applied to the first solenoid from a first polarity to a second polarity. The controller (12) is further configured to hold the voltage at the second polarity for a predetermined time period and a predetermined amplitude to decrease the induced current. The predetermined time period or the predetermined amplitude is determined based on the first signal.

Abstract: The invention relates to an internal combustion engine comprising a fuel injector (2) for each cylinder; a fuel injection control unit (4) for controlling fuel injection quantity and a piston (5) in each cylinder whose compression action causes a mixture of air and fuel to be ignited. The engine is further provided with inlet and outlet valves (6, 7) and various sensors (12-16) for measuring various engine operating parameters. During compression ignition mode, the control unit (4) is arranged to select a ?-value from a map stored in the control unit, which value is a function of engine load and engine speed, and to compare the actual ?-value with the selected ?-value; whereby the control unit is arranged to adjust the intake manifold pressure as a function of the difference between the said ?-values in order to obtain the selected ?-value. The invention further relates to a method for operating the engine and a computer readable storage device (4).

Abstract: A system and method for controlling first and second phase shiftable camshafts in a variable cam timing engine is provided. The method includes determining when the first camshaft is moving toward a first scheduled phase angle with respect to the crankshaft with a larger camshaft angular positioning error than the second camshaft. Finally, the method includes slowing down the first camshaft so that synchronized camshaft positioning can be better achieved.

Abstract: A system is described for minimizing engine torque disturbances that would otherwise cause degraded drive feel by a vehicle driver. The system utilizes multiple torque transmission paths of a transaxle unit mounted to the engine. The system manipulates the torque transmitted by adjusting the clutches of multiple torque transmission paths so that the torque disturbance in the engine results in relatively constant vehicle drive torque. In one example, a potential torque increase at high speed and low airflow that may be cause using electronically actuated valves is compensated for using multiple paths of the transmission. In this way, relatively constant output torque can be maintained.

Abstract: A method is described for controlling lean and rich operation of an internal combustion engine coupled to a lean NOx trap. In one example, the termination of the lean air-fuel mixture is based on an oxygen storage capacity and temperature of the NOx trap. In another example, the level and duration of rich air-fuel ratio purging operation is also controlled based on the oxygen storage capacity of the NOx trap.

Abstract: The present invention is a dual-stage fuel injection strategy for compression ignition engines in which 15-40% of the fuel is injected into the combustion chamber no later than about −20 to −30 CA ATDC and as early as IVC. The remaining fuel is then injected in one or more fuel pulses, none of which start before about −20 to −30 CA ATDC. The fuel injected early in the compression stroke forms a lean mixture that burns with low soot and low NOx emissions. The combustion of that fuel serves to increase in-cylinder temperature such that the ignition delay of subsequent fuel injection pulses is short. This mode is utilized when it is predicted that a NOx spike is imminent. Various other alternative methods for reducing NOx spikes are also disclosed such as specialized EGR systems that can provide EGR with low manifold vacuum.

Abstract: Various systems and methods are disclosed for carrying out combustion in a fuel-cut operation in some or all of the engine cylinders of a vehicle. Further, various subsystems are considered, such as fuel vapor purging, air-fuel ratio control, engine torque control, catalyst design, and exhaust system design.

Abstract: A system and method for removing NOx from an emission control device is provided. The emission control device is coupled adjacent and downstream of an oxidation catalyst. The method includes adding a reductant to the exhaust gases flowing into the oxidation catalyst. The method further includes partially oxidizing the reductant in the oxidation catalyst to transition a remaining portion of the reductant into a vapor phase. Finally, the method includes oxidizing the remaining portion of the reductant in the emission control device to remove NOx from the device.

Abstract: A method and system are provided for controlling the air/fuel ratio provided to an internal combustion engine during the time period when a hydrocarbon trap, coupled downstream of time engine, is being purged. In particular, the air/fuel ratio provided to the engine is biased rich of stoichiometry when the downstream hydrocarbon trap is being purged.