单项选择题 Because the timing of injection is crucial, （） mounted on the camshaft, which is driven by the crankshaft are used to operate the fuel pumps, one of which is provided for each cylinder.

单项选择题 Fuel has to be injected into the engine at a high pressure so that it （） correctly.

单项选择题 Cylinder liners from older lower powered engines had a uniform wall thickness and the cooling was achieved by circulating cooling water through a space formed between （）.