汽车专业英语课件4chapter2627

1、汽车专业英语课件4chapter2627汽车专业英语课件4chapter2627学习内容本次课学习内容、目标和重点难点学习目标难点重点EFI systems GDI1.掌握EFI的原理、主要组成系统部件的英文名称；掌握EFI的分类英文术语2.掌握GDI系统的控制原理和控制模式1.重点为记忆英文专业术语、GDI控制原理2.难点需要记忆的生词偏多3.汉译准确表达也是难点学习内容本次课学习内容、目标和重点难点学习目标难点重点EFIChapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System asse

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3、tku:lntn.冷却液Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System deliverydilivrin Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System 1. Types of Pulse Fuel Injection Systems In the electronic fuel injection system, the injector may be opene

4、d and closed by electrical signals. This is a pulse fuel injection system. The pulse injection system is usually electronically controlled. Although there are a number of design differences between various pulse fuel injection systems, the operating principles are very similar. The throttle body inj

5、ection system (Fig.2-9 left) uses an assembly containing one or two fuel injectors. The assembly is mounted at the entrance to the intake manifold and injects fuel ahead of the throttle valve. These systems are also called single-point injection（SPI）or central fuel injection. Multi-point injection s

6、ystems (Fig.2-9 right), also called multi-port injection（MPI）systems, deliver fuel at the engine intake ports near the intake valves.2.6.2 Text Chapter 2 Internal C Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System 2. Pulse Fuel Injection System Components The typical

7、 pulse injection system (Fig.2-10) can be broken into three subsystems: Air induction system. The system consists of an air cleaner assembly, throttle body, and intake manifold (Fig.2-10). The throttle body section contains the throttle valve, which is opened and closed by the driver to control the

8、amount of air entering the intake manifold. Fuel delivery system. The fuel delivery system (Fig.2-10）provides the fuel which mixes with the air. The main parts of the system are shown in Fig.2-11 and Fig.2-12. Pressure is provided by an electric fuel pump. Chapter 2 Internal C Chapter 2 Internal Com

9、bustion Engine2.6 Gasoline Electronic Fuel Injection System Fig.2-9 Single-point injection (left) and multi-point injection system (right) Chapter 2 Internal C Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System Fig.2-10 A typical pulse injection system Chapter 2 Intern

10、al C Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System Fig.2-11 Fuel delivery system Chapter 2 Internal C Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System Fig.2-12 Fuel delivery system of a car Chapter 2 Internal C Chapter 2 Internal C

11、ombustion Engine2.6 Gasoline Electronic Fuel Injection System Fig.2-12 Fuel delivery system of a car Chapter 2 Internal C Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System Electronic control system. The computer receives signals from a number of sensors whenever the e

12、ngine is running (Fig.2-13). From this input, the computer evaluates engine fuel needs and adjusts injector pulse width accordingly. Modern computers control many other engine systems in addition to the fuel injectors（Fig.2-10）. The sensors monitor various engine functions and feed this information

13、to the computer. The number and types of sensors vary with the system. Chapter 2 Internal C Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System Fig.2-13 Engine electronic control system Chapter 2 Internal C Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fue

14、l Injection System The oxygen sensor monitors the amount of oxygen in the engines exhaust gases. The computer uses signals from the oxygen sensor to control the air-fuel mixture. The oxygen sensor is generally mounted in the exhaust manifold. The engine speed sensor monitors engine RPM. Many speed s

15、ensors are mounted in the distributor. In other systems, the speed sensor is mounted so that it can monitor crankshaft or camshaft rotation. These speed sensors also indicate the crankshaft and camshaft position so that the computer can open the injector before the intake valve opens. Throttle posit

16、ion is relayed to the computer by the throttle position sensor. Throttle position sensors are installed on the throttle body. Chapter 2 Internal C Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System Engine load is transmitted to the computer by means of an intake manifo

17、ld absolute pressure sensor. The sensor converts manifold vacuum into a small electrical signal. This input allows the computer to increase fuel supply when the engine is under load and needs a richer mixture, and decrease fuel supply when engine load is light.Every injection system has a temperatur

18、e sensor to measure engine coolant temperature. Many injection systems have an additional sensor to measure the temperature of the incoming air.Some late model fuel injection systems monitor the amount of air entering the engine by using an airflow sensor（Fig.2-10）. The computer takes this input and

19、 compares it with engine RPM and manifold vacuum to determine the amount of fuel to inject. There are three types of airflow sensors, the heated wire, the air valve and the Karmann vortex. Chapter 2 Internal CChapter 2 Internal Combustion Engine2.7 Gasoline direct injection drasticdrstika.剧烈的，猛烈的res

20、ponserispnsn.反应，响应efficiencyifinsin.效率，效能，有效性ultra-leanltrli:na.极端稀薄的，超稀薄deploydipliv.展开，部署homogeneoushmi:njsa.相似的，均匀的stratifystrtifaia. (使)成层，（使）分层2.7.1 New Words and PhrasesChapter 2 Internal Combustion Chapter 2 Internal Combustion Engine2.7 Gasoline direct injection Although MPI provides a drast

21、ic improvement in response and combustion quality, it is still limited due to fuel and air mixing prior to entering the cylinder.To further increase throttle response and combustion efficiency, while lowering fuel consumption and increasing output, systems may use direct injection. Gasoline direct i

22、njection engines are engineered to inject the gasoline directly into the cylinder in a manner similar to diesel direct injection engines (Fig.2-14).Direct injection is designed to get better fuel economy. This is accomplished by enabling combustion of an ultra-lean mixture under many operating condi

23、tions. Direct injection is also designed to allow higher compression ratios, delivering higher performance with lower fuel consumption. Currently, direct injection gasoline engines are being deployed throughout the world in passenger cars.2.7.2 Text Chapter 2 Internal C Chapter 2 Internal Combustion

24、 Engine2.7 Gasoline direct injection Fig.2-14 Gasoline direct injectionA variety of air-fuel mixtures can be created according to changes in the fuel injection timing. The GDI engine provides both lower fuel consumption and higher output. This is achieved with the use of two combustion modes. These

25、two modes are represented in Figure 2-15. Chapter 2 Internal C Chapter 2 Internal Combustion Engine2.7 Gasoline direct injection Figure 2-15 Mitsubishi GDI uses two combustion modes Chapter 2 Internal C Chapter 2 Internal Combustion Engine2.7 Gasoline direct injection Ultra-lean Combustion Mode. Und

26、er most normal driving conditions, up to speeds of 120 km/h, the Mitsubishi GDI engine operates in ultra-lean combustion mode, resulting in less fuel consumption. In this mode, fuel injection occurs at the latter stage of the compression stroke and ignition occurs at an ultra-lean air-fuel ratio of 30-40. This operating mode is also called as stratified-charge mode. Superior Output Mode. When the GDI engine is operating with higher loads or at higher speeds, fuel injection takes place during the intake stroke. This optimizes combustion by ensuring a homogen