外文文獻(xiàn)翻譯中英文對照發(fā)動機(jī)基本原理-展示頁
2024-12-18 05:20本頁面
【正文】 . The connecting rod transmits the upanddown 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 pression ratio are two frequently used engine specifications. Displacement indicates engine size, and pression ratio pares the total cylinder volume to pression 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 plete. The 4 stroke engine is also called Otto, who first applied the principle in 1876. In the 4 stroke engine, four strokes of the piston in the cylinder are required to plete one full operating cycle. Each stroke is named after the action it performs intake, pression, power, and exhaust in that order. （ 1） Intake stroke As the piston moves down, the vaporized mixture of fuel and air enters the cylinder through the open intake valve. To obtain the maximum filling of the cylinder the intake valve opens about 10176。天津職業(yè)技術(shù)師范大學(xué) 2021屆本科生畢業(yè)設(shè)計 Engine Fundamentals Automobiles have been operated successfully by electric motors ,steam engines ,and internal bustion engines .The internal bustion engine burns fuel within its cylinders and converts the expanding force of the burning fuel ,or bustion, into a rotary force used to propel the vehicle. There are several types of internal bustion engines: twoand fourcycle reciprocating piston engines ,gas turbine engines .However ,fourcycle reciprocating engines have been refined to such a degree that they have almost plete dominance of the automotive field .Engines of other types are described in Chapter 18 ,Diesel and Other Engines. Many things are demanded of an engine used to propel an automobile. Some of the requirements are: （ 1） Ease of starting. （ 2） Reliability. （ 3） Power. （ 4） Responsiveness. （ 5） Economy in fuel ,oil ,and ,repairs. （ 6） Ease of handling. （ 7） Quiet operation. Some of these factors conflict .For example ,a great amount of power can be had from an engine of sufficient size, but a supersize engines is not economical to operate .Therefore ,all automobile engines are a promise in order to obtain the desirable bination of performance and economy. Engine fuels Internal bustion engines can be made to operate on almost anythi ng that can be converted into a bustible gas, such as wood ,coal, alcohol, vegetable oils, mineral oils, etc. However, because of convenience, a variety of petroleum products are monly used as fuel :gasoline, kerosene ,fuel oil ,liquefied petroleum gas (LPGas) ect. What kerosene ,fuel oil ,or LPGas is used it is necessary to alter the design of the engine to achieve efficient operation. 天津職業(yè)技術(shù)師范大學(xué) 2021屆本科生畢業(yè)設(shè)計 Engine Deign Gasoline engines used in automotive vehicles are of two basic types :fourcycle engines and twocycle engines .Either type may be watercooled ,or aircooled .Four ,six, and eightcylinder engines are mon However, three, five, ten ,and twelvecylinder engine are available. Almost all automobile engines have more than one cylinder. These cylinders can be arranged in an inline ,opposed ,or Vtype configuration. Engines for other purpose ,such as aviation, are arranged as radial, inverted inline ,inverted V, and Xshaped configurations. Reciprocating Engines In the typical automobile engine, a piston reciprocates (moves back and forth) within each cylinder. E
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