An internal combustion engine includes a variable valvetrain system for improving the range of controllability of the internal EGR technique adjusts the internal EGR lift in a more favorable window and position compared to the internal EGR window typically utilized. In particular, a combined change of lift, phase and duration of the internal EGR lift of the exhaust vale improves the controllability and stability of the desired amount of internal EGR. The present system achieves a high internal EGR capability at low loads and lower back pressure. The system also achieves controllability of internal EGR at high loads without requiring ultra low lifts. The system also allows warm-up of the exhaust after treatment system faster for higher conversion efficiency, reduced HC and NOx engine-out emissions and increased combustion stability.

The present invention is equipped with: a valve opening/closing timing control mechanism that sets the opening/closing timing of an exhaust valve; and a lock mechanism that holds the rotation phase of the valve opening/closing timing control mechanism in a first lock phase, in which the open state of the exhaust valve is maintained when the intake valve opens.

A vehicle includes an engine having a combustion chamber with an inlet and an outlet. Valves and valve actuators regulate open and closing of the inlet and the outlet. A plasma ignition source initiates ignition in the combustion chamber. A controller is in communication with the inlet valve actuator and outlet valve actuator. The controller is configured to detect a transition from a first combustion mode of the engine to a second combustion mode of the engine. The controller is also configured to change at least one of an opening time, a closing time, and an open duration of the first valve in response to detecting the transition.

A method and system for improving starting of an engine is presented. In one example, the method selects a first cylinder to receive fuel since engine stop the cylinder's position relative to the cylinder's top-dead-center compression stroke. The method also describes adjusting a number of fuel injections for a first combustion event since engine stop.

Methods and systems are provided for cleaning out condensate stored at a charge air cooler. In response to increased condensate accumulation at a charge air cooler, airflow through the engine is increased to purge the condensate while an engine actuator is adjusted to maintain engine torque. Combustion stability issues of engine cylinders are addressed by adjusting fueling of each cylinder individually during condensate ingestion.

An internal combustion engine includes a variable valvetrain system for improving the range of controllability of the internal EGR technique adjusts the internal EGR lift in a more favorable window and position compared to the internal EGR window typically utilized. In particular, a combined change of lift, phase and duration of the internal EGR lift of the exhaust vale improves the controllability and stability of the desired amount of internal EGR. The present system achieves a high internal EGR capability at low loads and lower back pressure. The system also achieves controllability of internal EGR at high loads without requiring ultra low lifts. The system also allows warm-up of the exhaust after treatment system faster for higher conversion efficiency, reduced HC and NOx engine-out emissions and increased combustion stability.

A vehicle includes a turbocharger, an exhaust-side variable valve, a vacuum servo device, an exhaust-side negative pressure hose, an exhaust-side check valve, a negative pressure supply valve, and circuitry. The exhaust-side negative pressure hose connects the vacuum servo device and a negative pressure extracting portion disposed in the exhaust passage. The exhaust-side check valve is disposed in the exhaust-side negative pressure hose to permit a gas flow only from the vacuum servo device to the exhaust passage. The negative pressure supply valve is provided in the exhaust-side negative pressure hose to open and close the exhaust-side negative pressure hose. The circuitry configured to control the exhaust-side variable valve to delay the valve timing with respect to an exhaust top dead center so as to generate negative pressure in the exhaust passage and to open the negative pressure supply valve while the negative pressure is generated in the exhaust passage.

Methods and systems are provided for reducing EGR estimation errors during lean engine operating conditions. During lean engine operation, EGR is disabled if the estimated exhaust air-fuel ratio becomes leaner than a lean threshold. The lean threshold is adjusted based on an upper limit of EGR errors that may be tolerated by the engine at a given engine speed and load.

A system and method for cylinder deactivation in a multi-cylinder diesel engine comprises pumping air in to an intake manifold of the diesel engine using a turbocharger. Air is pumped in to the intake manifold using an intake air assisting device. And, fuel injection is selectively deactivated to at least one of the cylinders in the diesel engine. An intake valve and an exhaust valve is selectively deactivated for the at least one of the cylinders of the diesel engine.

When a specific condition requiring a rise in exhaust gas temperature is satisfied, a required fuel amount to be injected from an injector (21) is injected in a split manner, such that the fuel injection is divided to: a main injection (X1) to be initiated a given period before a compression top dead center; an auxiliary injection (X2) to be initiated after initiation of auto-ignited combustion of an air-fuel mixture consisting of air and the fuel injected by the main injection (X1) and before an assumed peak timing (Pk) of a heat release rate (RH) from the combustion based on the main injection (X1); and a post injection (X3) to be initiated after the assumed peak timing (Pk) and before completion of combustion based on the main injection (X1) and the auxiliary injection (X2). This makes it possible to raise an exhaust gas temperature while sufficiently ensuring auto-ignitability and fuel economy performance.