Volvo Personvagner Ab

Atlas Copco Rock Drills Ab

Jan Knutsson

Roland Pettersson

Lars Sandstroem

Mikael Ramstroem

G&ouml;ran Almkvist

Jan-Erik Larsson

Lars Allerv&aring;g

Henrik Magn&eacute;

Lars Sandström

Mikael Ramström

The invention relates to a method of reducing emissions in the exhaust gases from an internal combustion engine that has at least one cylinder to which an air/fuel mixture is supplied when a crankshaft of the internal combustion engine is rotated, at least one inlet valve, at least one inlet duct connecting to the inlet valve, at least one exhaust valve, at least one exhaust duct connecting to the exhaust valve, control members for controlling the opening and closing of the inlet and exhaust valves, and a piston reciprocating between a top dead-center position and a bottom dead-center position in the cylinder. The method comprises the steps of supplying a lean air/fuel mixture to the cylinder, controlling the internal combustion engine so that it works at high load, and controlling the exhaust valve so that it opens when the piston is located in the bottom dead-center position. The exhaust valve is preferably controlled so that it closes after the induction stroke has started. According to one embodiment of the invention, the internal combustion engine is controlled so that the crankshaft rotates at an essentially constant speed within the range of about 1000 to about 2000 rpm.

Method of reducing emissions in the exhaust gases from an internal combustion engine

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Nödinge, Sweden

Jan Knutsson