Four-stroke gasoline engine with direct injection and method for valve control
OwnerUlrich Kramerinventor
Life of this patent
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Abstract
The invention relates to a method for actuating intake valves and exhaust valves of a four-stroke direct-injection gasoline engine. At low torque, a parallel retardation of the intake valves and exhaust valves is carried out, so that, at the commencement of the intake stroke, the exhaust valve is still open and the intake valve is still closed after top dead center (TDC) of the piston. High internal exhaust gas recirculation (EGR) occurs, irrespective of the pressure in the intake manifold. The resulting internal EGR is sufficient to displace the 50% MFB timing to its optimal position after TDC and to reduce nitrogen oxide emissions.
Claims12
A method for controlling at least one intake valve and at least one exhaust valve of a four-stroke direct-injection gasoline engine under low torque operation, comprising:
- retarding an opening of the intake valve so that the intake valve opens after top dead center (TDC) of the piston.
A four-stroke, direct-injection gasoline engine having at least one intake valve, at least one exhaust valve, and a camshaft, comprising:
- an engine controller electrically coupled to the engine and the camshaft, said engine controller causes a phase displacement of the camshaft to cause an opening of the intake valve so that the intake valve opens after top dead center (TDC) of the piston.
Dependencies are inferred from the claim text.