Automobile Engine
Most automobile engines are internal combustion, reciprocating four-stroke gasoline engines, but other types have been used, including the diesel, the rotary the two-stroke, and super charged Reciprocating means up and down or back and forth. It is the up and down action of a piston in the cylinder block, or engine block that generates the power. The block is an iron or aluminum casting that contains engine cylinders and passages called water jackets for coolant circulation. The top of the block is covered with the cylinder head, which forms the combustion chamber. The bottom of the block is covered with an oil pan or oil sump. Power is produced 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. The piston is attached to the top of a connecting rod 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 mounted on the crankshaft with large bearings called rod bearings. Similar bearings, called main bearings, are used to mount the crankshaft in the block. The diameter of the cylinder is called the engine bore. Displacement and compression ratio are two frequently used engine specifications. Displacement indicates engine size, and compression ratio compares the total cylinder volume to compression chamber volume. The term stroke is used to describe the movement of the piston within the cylinder, as well as the distance of piston travel. Depending on the type of engine the operating cycle may require either two or four strokes to complete. The four-stroke engine is also called Otto cycle engine, in honor of the German engineer, Dr. Nikolaus Otto, who first applied the principle in 1876. In the four-stroke engine, four strokes of the piston in the cylinder are required to complete one full operating cycle. Each stroke is named after the action it performs intake, compression, power, and exhaust in that order
大多数汽车的发动机是内燃机,往复四冲程汽油机,但是也有使用其他类型的发动机,包括柴油机,转子发动机,二冲程发动机和增压发动机。往复的意思就是上下运动或前后运动,在往复式发动机中,气缸中活塞的上下运动产生发动机的动力,发动机的缸体是铸铁或铸铝制造而成,构成发动机的气缸和冷却液循环水套。缸体的顶部是气缸盖,由此形成燃烧室,缸体底部是油底壳。气缸中活塞的直线运动产生动力,然而,必须将直线运动转化成旋转运动,使汽车车轮转动,活塞销将活塞连接在连杆顶部,连杆底部与曲轴连接,活塞销将活塞连杆顶部、连杆底部与曲轴连接、连杆将活塞的往复运动传递给曲轴,曲轴将其转化为旋转运动,连杆是用连杆曲轴安装在曲轴上的,用类似的轴承 即主轴承将曲轴固定在缸体内。气缸的直径称为发动机的内径,排量和压缩比 是两个常用的发动机参数,排量指发动机的大小,压缩比是气缸总容积与燃烧 室压缩容积之比。冲程这一术语是用来说明活塞在气缸内的运动,即活塞行程 的距离。根据发动机类型,需要二冲程或四冲程来完成一个工作循环。四冲程发动机也称奥托循环发动机,这是为了纪念在1876年第一个应用该原理的德国工程师奥托。在四冲程发动机中,气缸活塞需四冲程来完成一个完整的工作循环,每个冲程根据其行为命名分别为:进气、压缩、作功和排气四个冲程。