汽车专业英语13

Chapter 3 Gasoline Fuel System
Qu.2: List the main function of the carburetor.
Metering － correct proportions of fuel and air
Atomization － spray fine particles to great air Distribution － deliver uniform mixture to manifold
Carburetor (mix) 化油器
burn
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Chapter 3 Gasoline Fuel System
4) Fuel pump: Most cars today have a mechanical fuel pump. This pumps fuel out of the tank and through the fuel lines to the carburetor or injection system. In most cars, the pump is mounted on the engine block. Some cars have an electric fuel pump. This pump mounts in the fuel tank with the fuel pickup and the fuel-gauge-sending unit.
Automotive Engineering English
浓混合气 稀混合气
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Chapter 3 Gasoline Fuel System
1) Cold star 2) Post-start phase 3) Warm-up 4) Acceleration 冷启动 后启动阶段 暖机 加速
Operating conditions
float 浮子 float chamber 浮子室 air filter 空气滤清器 venturi 喉管 Jet 量孔
idling valve
怠速阀
nozzle
喷 嘴
advance angle 提前角 discharge tube 喷管 dwell angle 持续角
petroleum
石
油
throttle 节气门
2) Increasing the pressure of the fuel mixture in the combustion chamber before ignition helps to increase the power of an engine. This is done by compressing the fuel mixture to a smaller volume. Higher compression ratios not only boost power but also give more efficient power. But as the compression ratio goes up, knocking tendency increases.
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Chapter 3 Gasoline Fuel System
6) A carburetor delivers fuel in proportion to the amount of air flowing through it. As you press on the accelerator pedal, the throttle valve opens wider to draw more air through the carburetor. The carburetor provides richer or leaner mixtures, depending on a number of factors: engine speed, load, temperature, and throttle position. To meet complicated demands, a carburetor is a highly intricate device, with many internal passages and parts. 化油器输送的燃油与流经化油器的空气量成一定比例。踩下 加速踏板，节气门开度变大，化油器吸入的空气增加。化油 器可提供较浓或较稀的混合气，这取决于发动机转速、负荷 、温度和油门开度等因素。为满足复杂的要求，化油器的结 构也很复杂，其上有很多内部通道和部件。
Complete burn
Theoretical requirement A / F = 14.7 : 1 (by mass)
λ Excess-air factor 过量空气系数
air mass suppliedtheoretica l requiremen t
λ <1 Rich mixture λ >1 Lean mixture
Fuel pump
汽油泵
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Chapter 3 Gasoline Fuel System
5) Fuel pump: The rotation of the lobe moves a rocker arm in the pump. Inside the pump, a flexible diaphragm connects to the rocker arm though a diaphragm spring, pull rod and link. Inlet port
Chapter 3 Gasoline Fuel System
Qu.1: What’s the meaning of the air/fuel ratio (A/F)? A/F is the proportion of air to fuel, which is stated in term of mass, different fuel has different air/fuel ratio.
凸圆旋转带动油泵 中的摇臂运动。油 泵中可变形膜片的 泵膜通过膜片回位 弹簧和拉杆与摇臂 相连。
Outlet port Diaphragm Diaphragm spring
Rocker arm
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Chapter 3 Gasoline Fuel System
5) Part load
6) Full load 7) Idling 8) Overrun
部分负荷
全负荷 怠速 超速
Different fuel requirement
9) Engine-speed limiting 发动机限速 10) High altitudes 高海拔
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在点火前增加燃烧室内可燃混合气的压力有助于提高发动 机的功率，这是通过把可燃混合气压缩到一个极小的体积 来实现的。高的压缩比不仅可以增加功率，而且会带来更 多的有效功率。但随着压缩比的增加，爆震的可能性也会 增加。
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Chapter 3 Gasoline Fuel System
Carburetor
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Chapter 3 Gasoline Fuel System
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Chapter 3 Gasoline Fuel System
needle valve 针阀
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Chapter 3 GasolFra bibliotekne Fuel System
1) Gasoline must vaporize easily. This characteristic, called volatility, is important. However, it must not vaporize too easily, or it will turn to vapor inside the fuel tank or fuel lines. Inside the fuel line, fuel vapor may block the flow of liquid gasoline. This is called vapor lock. Vapor lock is common in fuel lines where the inlet side of the pump is exposed to high temperatures.
3) Two primary standard reference fuels, normal heptane and iso-octane arbitrarily assigned 0 and 100 octane number, respectively, are then blended to produce the same knock intensity as the test sample. The percentage of iso-octane in blend is considered the octane number of the test sample. Thus, if the matching reference blend is made up of 15% nheptane and 85% isooctane, the test sample is rated 85 motor or research octane number, according to the test method used.