单项选择题
A.reduce engine exhaust noise B.reduce engine back pressure C.recover heat which otherwise would be lost D.increase turbocharger efficiency
A.direction of air flow within the cylinder B.sequence of port opening C.method of opening exhaust ports D.volume of air admitted to the cylinder
A.sulfite or hydrazine B.sulfite or hygroscopic sulfite C.bromide or hydrazine D.bromide or hygroscopic sulfite