新编汽车专业英语第3版黄汽驰电子课件Unit1PassageA.pptxVIP

Unit One　Classification of Enginesand Their Operating Principles;Passage A Classification of Engines;Automotive engines are classified as the reciprocating engine and rotary engine according to the way they work; as the gasoline engine and diesel engine according to fuel they burn; and as the inline engine, V-type engine, boxer engine and W-type engine according to the number and the arrangement of cylinders．;Reciprocating Engine and Rotary Engine;A rotary engine was developed in 1954． In this engine a three-sided rotor revolves within a combustion chamber as shown in Fig.1-2． The expanding gas turns the rotor, producing power and the exhausted gas is expelled． The rotary engine has no reciprocating parts such as pistons and valves． It develops a high horsepower, and produces no vibration, but its fuel consumption is higher than that of the reciprocating engine．;Gasoline Engine and Diesel Engine;It is also called the spark ignition engine． The features of the engine are high in speed, smooth in operation, simple in the structure, light in weight and low in cost． Almost all cars use gasoline engines． ;Diesel engines use diesel as fuel． It works by compressing the air inside the cylinder to make diesel coming in from the injector burn, producing the power to drive a car (see Fig.1-3b). So it is called the compression ignition engine． A diesel engine is more powerful and delivers better fuel economy than a gasoline engine． Diesel engines are often found on large trucks, buses and some of cars．;Inline engine, V-type engine, boxer engine and W-type engine;Inline engine has the cylinders arranged in a straight line with a single cylinder head． Almost all 4-cylinder engines use this arrangement (see Fig. 1-4). There are also some 5- and 6-cylinder-inline engines．;V-type engine has two rows of cylinders side-by-side with two cylinder heads, and it is commonly used in V-6, V-8, and V-12 configurations at a 90 or 60 degree angle to each other (see Fig.1-5