Four-stroke automotive piston engine exhaust valves open and closed several times during each exhaust cycle

摘要

A four-stroke automotive piston engine (4) has an exhaust turbocharger (2). Each cylinder (8) has one or more outlet valves. During each cylinder exhaust cycle exhaust gases are discharged to the exhaust gas turbocharger, raising the turbocharger pressure at low engine speed and thus the engine torque. During the exhaust cycle the valve is opened closed several times.