Turbo-charged combustion engine with bypass valve serving intake air-cooler - allows cooling of recirculated combustion prods. or of fresh air for combustion purposes according to engine load.

摘要

The combustion prods. from e.g. four cylinders (12) are exhausted (14) through a turbocharger (16) whose turbine (18) drives a compressor (20) of the intake air (22). A changeover valve (28) closes the bypass line (34) to the compressed air which passes through the cooler (32) when higher engine output is demanded. For lower output, the exhaust gas turbine is bypassed (44) by a regulator valve (46) and exhaust is admitted by another valve (56) to the cooler, while the changeover valve holds the bypass line (34) open. The throttle valve is electrically controlled. ADVANTAGE - NOx emission is reduced over a wide range of load, with the same cooler operating on the combustion air at higher loads and on recirculated exhaust gas at lower loads.