单项选择题
A.increased air pressure differenced before and aft air cooler
B.reduced exhaust temperature in all cylinders
C.reduced temperature difference between water inlet and outlet
D.both A and C
单项选择题 In a four stroke engine, which process lasts the longest period?（）
单项选择题 In the two stroke diesel engine, it is designed so that the oil impingement is timed to proceed only on the piston ring belt during（）
单项选择题 One advantage of a flash distilling plant when compared to a submerged tube distiller is（）