Method of controlling the process of combustion in an internal combustion engine, and engine with means for controlling the engine valves
First Claim
1. Method of controlling the combustion process in the combustion chamber (3) of a four-stroke internal combustion engine with at least one cylinder (1) having at least one inlet valve (9) and one exhaust valve (11), comprising supply of a homogeneous fuel/air mixture to the combustion chamber, and compression of the mixture to self-ignition, characterized in that the exhaust valve (11) during the exhaust stroke of the piston (4) is controlled so that it, at least within a lower rpm range, closes before the piston has reached its upper dead center point, the degree of opening of the valve being varied, depending on engine load and rpm so that the amount of residual gas at closing of the valve is greater at low loads and high rpm than at high loads and low rpm, to thereby vary the ignition delay by varying the degree of dilution of the fuel/air mixture with residual gases in the combustion chamber.
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Accused Products
Abstract
Four-stroke internal combustion engine with electrically operated inlet and exhaust valves (9,11) and means for supplying a homogeneous fuel/air mixture to the engine cylinders (1). The valves are controlled by a control unit (15), which, within a lower rpm range, closes the exhaust valve (11) before the piston (4) has reached its upper dead center point. Under the effect of trapped residual gas, a temperature increase is achieved, which results in compression ignition of the fuel/air mixture. The control unit (15) controls the exhaust valve (11), so that the amount of residual gases in the cylinders at the closing of the exhaust valves is greater at low loads and high rpm than at high loads and low rpm, in order to control the ignition delay in this manner.
23 Citations
12 Claims
- 1. Method of controlling the combustion process in the combustion chamber (3) of a four-stroke internal combustion engine with at least one cylinder (1) having at least one inlet valve (9) and one exhaust valve (11), comprising supply of a homogeneous fuel/air mixture to the combustion chamber, and compression of the mixture to self-ignition, characterized in that the exhaust valve (11) during the exhaust stroke of the piston (4) is controlled so that it, at least within a lower rpm range, closes before the piston has reached its upper dead center point, the degree of opening of the valve being varied, depending on engine load and rpm so that the amount of residual gas at closing of the valve is greater at low loads and high rpm than at high loads and low rpm, to thereby vary the ignition delay by varying the degree of dilution of the fuel/air mixture with residual gases in the combustion chamber.
- 7. Four-stroke internal combustion engine with at least one cylinder (1) having at least one inlet valve (9) and one exhaust valve (11), means for supplying a homogeneous fuel/air mixture to the combustion chamber (3) of the cylinder, and control means (15) for at least varying the degree of opening of the exhaust valve (11), characterized in that the control means (15) are so arranged to control the exhaust valve (11) during the exhaust stroke of the piston (4), that the valve, at least within a lower rpm range, closes before the piston has reached its upper dead center point, and that the degree of opening of the valve is varied, depending on the engine load and rpm, so that the amount of residual gases in the combustion chamber at the closing of the valve is greater at low loads and higher rpm than at high loads and lower rpm, to thereby vary the ignition delay by varying the degree of dilution of the fuel/air mixture with residual gases in the combustion chamber.
Specification