单项选择题
A.turbocharger stalls
B.exhaust pressure increases
C.air charge density decreases
D.scavenge effect increases
单项选择题 The diameter of a piston is usually less at the crown than at the skirt, in order to （）.
单项选择题 The opening of an exhaust valve on a modem, large, low-speed, main propulsion diesel engine may be actuated by （）.
单项选择题 In a diesel engine, excessive cylinder liner wear will cause （） (1) increased blow-by (2) wear between the piston ring and groove