Chapter One Engine System Unit One Engine O all automobile components, an automobile engine is the most complicated assembly with dominant eflects on the function of an automobile. So, the engine is generally called the"heart"of an automobile There are actually various types of engines such as eleetrie motors, stream engines, and internal combustion engines. The intemal combustion engines seem to have almost complete dominance of the au tomotive field. The intemal combustion engine, as its nane indicates. bums fuei within the cylinders and converts the expanding force of the combustion into rotary force used to propel the vehicle Engine is the power source of the automobile. Power is prduced by the linear motion of a piston in a cylinder. However, this linear motion must be changed into rotary motion to turn the wheels of cars or trucks. The piston attached to the top of a connecting md by a pin, called a piston pin or wrist pin.The bottom of the: connecting rod is attached to the crankshaft. The connecting rod transmits the up-and-down motion of the piston to the crankshaft, which changes it into rotary motion. The connecting rod is mount ed on the crankshaft with large bearings called rud bearings, Similar bearings, called main bearings, are used to mount the crankshaft in the block, Shown in Fig 1-1 The diameter of the cylinder is called the engine bore. Displacement and compression ratio are two Fig 1-1 The engine co spark plug inlake valve exhaust valve -lifter 7-carnshaft gear-wheel 8-crankshaft pulley y--crsnkshaft timing gur 10--camshaft flywheel 14--ennecting rod 15--eyliixker blk