The heart of the diesel engine is the （） where the fuel is burnt and the power developed. A: crankcase B: cylinder C: scavenge box D: pisto

Which of the following operation will have a direct impact on the rate of wear in a cylinder liner （） A: amount of scavenge air to the cylinder B: quality of fuel injected C: viscosity of the lube oil D: compression ratio of the pisto

The burning of the fuel adds more heat to the air charge， causing it to expand and force the engine piston to do work on the crankshaftWhat does “it” mean in this sentence?（） A: the burning B: the fuel C: the air charge D: the engine pisto