,机电技术专业英语,2,Lesson Six,Text,Internalcombustion engines are those that burn fuel inside the engine. Those that burn gasoline are known as gasoline engines. Other types of internalcombustion engines burn heavier oils or fuels. Of these types the diesel engine has come into the widest use. Each of this engine has a few main working parts， the auxiliary parts are necessary to hold the working parts together or to assist the main working parts in their performance. The main parts are: (1) the engine block (2) the cylinder (3) cylinder head (4) the piston (5) the connecting rod (6) crankshaft,Principles of Engine Operation,Lesson Six,(7) camshaft (8) the fuel pump and fuel nozzle The engines require many systems for their performance. These are： (1) fuel system (2) ignition system (3) lubricating system (4) cooling system (5) starting system All engines convert one form of energy into another. Internalcombustion engines convert the chemical energy stored in their fuels into heat energy during the burning part of their operation. The heat energy is converted into mechanical energy by the expansion of gases against pistons attached to crankshafts. To transfer the energy resulting from this expansion into useful work, a construction such as shown in Figure B.5 is used.,Lesson Six,Figure B.5 Engine operation,Lesson Six,New Words and Expressions,Lesson Six,Lesson Six,Lesson Six,Notes,1, turning through onehalf of a revolution as the piston moves downward.,当活塞向下运动（一次），曲轴转半圈。 2. Attached被动结构的过去分词放在句首，形成倒装语序。 3.while under compression等while it is under compression,谢谢观赏,www.sciencep.com,Thank You !,