A METHOD AND A DEVICE FOR ENGINE BRAKING A FOUR STROKE INTERNAL COMBUSTION ENGINE

摘要

The invention relates to a method and an arrangement for engine braking a four-stroke internal combustion engine. The engine has for each cylinder (2) at least one inlet valve (7) and at least one exhaust valve (9) for controlling communication between a combustion chamber (5) in the cylinder (2) and an inlet system (8) and an exhaust system (10) respectively. In accordance with the invention) the arrangement also includes means for establishing communication between the combustion chamber (5) and the exhaust system (10) in conjunction with the exhaust stroke and also when the piston (3) is located in the proximity of its bottom-dead-centre position after the inlet stroke and during the latter part of the compression stroke and during at least a part of the expansion stroke. Communication of the combustion chamber (5) with the exhaust system (10) is effected upstream of a throttling device (13) provided in the exhaust system) this throttling device being operative to throttle at least a part of the flow through the exhaust system (10) during an engine braking operation, therewith to increase the pressure upstream of the throttling device (13).