INTERNAL COMBUSTION ENGINE MECHANISMS AND SYSTEMS
UNIT 4 As to the number of cylinders, most automobile engines have four or six cylinders, although some eight-, twelve- and sixteen- cylinder engines are in use. The single-cylinder engine runs roughly since three auxiliary strokes fall on a single power stroke. Besides, the engine weight per power unit is too high. To eliminate these shortcomings, multicylinder engines are built. Such engines comprise several cylinders whose connecting rods are connected to the crankthrows of the common crankshaft. The power strokes in the multicylinder engines are sequenced among the cylinders in such a way that the auxiliary strokes are always assisted by a power one. This decreases the weight of the flywheel, hence the engine weight per power unit, and provides smoother engine operation. In multicylinder engines the cylinders (usually grouped in a block) may be arranged in-line, vertically or at an angle from the vertical. Another arrangement is a V-type engine, where two blocks are set at a 90° angle. The internal combustion engine consists of the following mechanisms and systems. The crank mechanism takes the pressure of expanding gases and converts the reciprocating motion of the piston into the rotary motion of the crankshaft. The valve mechanism provides timely admission of the fresh charge into the cylinder and exhaust of the spent gases from it. The cooling system abstracts excessive heat from the engine parts. The lubricating system supplies oil to the friction surfaces of the engine parts, cools them partly, carries away mechanical impurities, and cleans the lubricating oil. The fuel system prepares the mixture of gasoline vapor and air, delivers it to the cylinders, and removes the products of combustion. The ignition system transforms the low-tension current into the high-tension current and feeds it to the spark plugs for igniting the mixture. 1. Выпишите из словаря транскрипцию и перевод встречающихся в тексте слов: Roughly, auxiliary, power, weight, multicylinder, sequence, flywheel, smooth, angle, exhaust, charge, friction, vapor, impurity, ignition, current.
|
