車輛工程專業(yè)畢業(yè)設計的外文翻譯-其他專業(yè)-資料下載頁
2025-01-19 01:45本頁面
【導讀】擎都成為內(nèi)燃機。最常見的內(nèi)燃機有四種：奧托循環(huán)式發(fā)動機，柴油機，轉(zhuǎn)子發(fā)動機。根據(jù)這四種發(fā)動機的優(yōu)點，把它們應用于不同的工況。是根據(jù)其發(fā)明者，德國機械師尼古拉斯.奧格事特.奧托的名字來命名的。它是一種用柴油作為燃料的先進的發(fā)動機。普遍用在電子控機械、戰(zhàn)斗機、公共汽車、貨車以及一些小車上。奧托式發(fā)動機和柴油機的工作方式都是二沖程或者四沖程。壓縮燃燒室是由一個一段由缸蓋?；钊纳舷逻\動使得氣缸與活塞間的空間發(fā)生大小。變化，從而改變壓縮空間的大小?；钊c曲軸之間通過連桿相互連接。多氣缸式發(fā)動機的曲軸，在每一個氣缸處都會多一個稱為。曲軸上接有飛輪并有平衡坑。在奧托式發(fā)動機上，并不是靠化油器來進行燃油霧化的，而是利用燃油的直接噴入，量對進氣充量進行壓縮。所有的發(fā)動機上，火花塞的位置都必須適宜。一個安裝在汽缸頂部被叫做火花塞的零件。在火花塞末端的兩極間有一個間隙，高壓。到加熱完成期間進行燃油噴射。
【正文】 ate an Ottocycle or diesel as a twostroke or twocycle engine with a power stroke every other stroke of the piston instead of once every four strokes. The power of a twostroke engine is usually double that of a fourstroke engine of parable size. The general principle of the twostroke engine is to shorten the periods in which fuel is introduced to the bustion chamber and in which the spent gases are exhausted to a small fraction of the duration of a stroke instead of allowing each of these operations to occupy a full stroke. In the simplest type of twostroke engine, the poppet valves are replaced by sleeve valves or ports (openings in the cylinderwall that are uncovered by the piston at the end of its outward travel). In the twostroke cycle, the fuel mixture or air is introduced through the intake port when the piston is fully withdrawn from the cylinder. The pression stroke follows, and the charge is ignited when the piston reaches the end of this stroke. The piston then moves outward on the power stroke, uncovering the exhaust port and permitting the gases to escape from the bustion chamber. In the 1950s the German engineer Felix Wankel developed an internalbustion engine of a radically new design, in which the piston and cylinder were replaced by a threecornered rotor turning in a roughly oval chamber. The fuelair mixture is drawn in through an intake port and trapped between one face of the turning rotor and the wall of the oval chamber. The turning of the rotor presses the mixture, which is ignited by a spark plug. The exhaust gases are then expelled through an exhaust port through the action of the turning rotor. The cycle takes place alternately at each face of the rotor, giving three power strokes for each turn of the rotor. Because of the Wankel engine39。s pact size and consequent lesser weight as pared with the piston engine, it appeared to be an important option for automobiles. In addition, its mechanical simplicity provided low manufacturing costs, its cooling requirements were low, and its low center of gravity made it safer to drive. A line of Wankelengine cars was produced in Japan in the early 1970s, and several United States automobile manufacturers researched the idea as well. However, production of the Wankel engine was discontinued as a result of its poor fuel economy and its high pollutant emissions. Mazda, a Japanese car manufacturer, has continued to design and innovate the rotary engine, improving performance and fuel efficiency. A modification of the conventional sparkignition piston engine, the stratified charge engine is designed to reduce emissions without the need for an exhaustgas recirculation system or catalytic converter. Its key feature is a dual bustion chamber for each cylinder, with a prechamber that receives a rich fuelair mixture while the main chamber is charged with a very lean mixture. The spark ignites the rich mixture that in turn ignites the lean main mixture. The resulting peak temperature is low enough to inhibit the formation of nitrogen oxides, and the mean temperature is sufficiently high to limit emissions of carbon monoxide and hydrocarbon.
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