Internal combustion engine and a method of operating same

Abstract

The invention relates to an internal combustion engine comprising an inlet manifold, at least one combustion chamber with at least two inlet valves and at least one outlet valve, a piston reciprocable in the or each chamber to define a variable volume space therein, and means for controlling the timing of the opening and closing of each of two of the inlet valves of the or each chamber independently so that opening of one of the independently controlled inlet valves of the or each chamber occurs during the exhaust stroke of the engine, opening of the other of the independently controlled inlet valves of the or each chamber, at a time when said one of the independently controlled inlet valves is closed, and when pressure in the or each chamber is lower than pressure in said inlet manifold, producing a predetermined pressure differential across said other of the independently controlled inlet valves, creating an in-flow to the or each chamber generating turbulence, at least some of which is present when combustion occurs in the or each chamber. Preferably for light load said one inlet valve closes during the induction stroke and the other inlet valve opens and closes during the compression stroke. For full load said one inlet valve closes during the compression stroke, whilst the other inlet valve opens and closes during the induction stroke, so that both inlet valves are open together during induction.