Types of Engines

V. Read the text about two types of engines and compare them. Use notes.

spark plug, n.–свеча зажиганияexhaust outlet, n. – выпуск

fuel injector, n.-топливная форсункаfuel inlet, n. – всасывание

two-stroke engine, n. – двухтактный двигатель

four-stroke engine, n. – четырёхтактный двигатель

oil sump, n. - масляный поддон valve, n.–клапан

crankshaft, n. – коленчатый вал piston, n. – поршень

compression stroke, n. – такт сжатия

combustion stroke, n. – рабочий ход

exhaust stroke, n.–такт выпуска

induction stroke, n. – ход (такт) впуска

top dead center, n.–верхняя мёртвая точка

bottom dead centre, n.–нижняя мёртвая точка

All motor vehicles have engines. The two most common types of engines for land vehicles are the petrol and the diesel engines. Petrol engines are usually lighter and smaller than diesel engines. Petrol engines are also less noisy than diesel engines. They usually go faster. On the other hand, diesel engines use less fuel and last longer than petrol engines. This is why larger vehicles such as trucks and trains use them. They are also safer than petrol engines, because there is less danger of fire.

All petrol engines have spark plugs and diesel engines do not have spark plugs. They have fuel injectors.

According to the engine cycle and configuration all internal combustion engines are divided into two stroke engines and four stroke engines.

For a four-stroke engine key parts of the engine include the crankshaft, one or two camshafts and valves. All four-stroke engines have an oil sump.

For a two-stroke engine there is an exhaust outlet and fuel inlet instead of a valve mechanism. They don’t use an oil sump because they have oil in the fuel.

In both types of enginesthere are one or more cylinders and for each cylinder there is a spark plug, a piston and a crank. The activities that take place in the engine cylinder can be divided into four stages, which are called strokes. The four strokes are: intake, compression, power and exhaust. "Stroke" refers to the piston movement. The upper limit of piston movement is called top dead centre, TDC. The lower limit of piston movement is called bottom dead centre, BDC. A stroke constitutes piston movement from TDC to BDC or from BDC to TDC. In other words, the piston completes a stroke each time it changes the direction of motion.