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1、复习,提问（教师说发动机配气机构汉语部件名称，同学回答英文名称）翻译VVT英文片段,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 GDI,1.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,Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System,New Words and Phrases,Cha
2、pter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System,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 opened and closed by electrical signals
3、.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 injection system(Fig.2-9 left)uses an asse
4、mbly 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 systems(Fig.2-9 right),also called multi-port
5、 injection（MPI）systems,deliver fuel at the engine intake ports near the intake valves.,Text,Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System,2.Pulse Fuel Injection System Components The typical pulse injection system(Fig.2-10)can be broken into three subsystems:Air i
6、nduction 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 amount of air entering the intake manifold.Fuel delivery system.The fuel delivery s
7、ystem(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 Combustion Engine2.6 Gasoline Electronic Fuel Injection System,Fig.2-9 Single-point injection(left)and multi-poi
8、nt injection system(right),Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System,Fig.2-10 A typical pulse injection system,Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System,Fig.2-11 Fuel delivery system,Chapter 2 Internal Combustion Engine2
9、.6 Gasoline Electronic Fuel Injection System,Fig.2-12 Fuel delivery system of a car,Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System,Fig.2-12 Fuel delivery system of a car,Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System,Electronic co
10、ntrol system.The computer receives signals from a number of sensors whenever the engine 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.
11、2-10）.The sensors monitor various engine functions and feed this information to the computer.The number and types of sensors vary with the system.,Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System,Fig.2-13 Engine electronic control system,Chapter 2 Internal Combustion
12、 Engine2.6 Gasoline Electronic Fuel 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 mo
13、nitors engine RPM.Many speed sensors 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
14、valve opens.Throttle position is relayed to the computer by the throttle position sensor.Throttle position sensors are installed on the throttle body.,Chapter 2 Internal Combustion Engine2.6 Gasoline Electronic Fuel Injection System,Engine load is transmitted to the computer by means of an intake ma
15、nifold 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 temperatu
16、re 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
17、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 Combustion Engine2.7 Gasoline direct injection,New Words and Phrases,Chapter 2 Internal Combusti
18、on Engine2.7 Gasoline direct injection,Although MPI provides a drastic 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 incr
19、easing output,systems may use direct injection.Gasoline direct injection 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
20、combustion of an ultra-lean mixture under many operating conditions.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.
21、7.2 Text,Chapter 2 Internal Combustion Engine2.7 Gasoline direct injection,Fig.2-14 Gasoline direct injection,A 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 th
22、e use of two combustion modes.These two modes are represented in Figure 2-15.,Chapter 2 Internal Combustion Engine2.7 Gasoline direct injection,Figure 2-15 Mitsubishi GDI uses two combustion modes,Chapter 2 Internal Combustion Engine2.7 Gasoline direct injection,Ultra-lean Combustion Mode.Under most
23、 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 o
24、perating 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 homogeneous,cooler air-fuel mixture which minimizes the possi
25、bility of engine knocking.This mode is also called as homogeneous-charge mode.,Chapter 2 Internal Combustion Engine2.7 Gasoline direct injection,Two main operating modes of Volkswagen AGs fuel stratified injection(FSI)which uses more operating modes and FSIs fuel-saving potential is shown in Figure
26、2-16.A typical pulse injection system with direct injection is given in Fig.2-17.,Chapter 2 Internal Combustion Engine2.7 Gasoline direct injection,Figure 2-16 Main operating modes and fuel-saving potential of Volkswagen AGs FSI direct-injection,Chapter 2 Internal Combustion Engine2.7 Gasoline direct injection,Fig.2-17 Gasoline direct injection system,小结与作业,掌握EFI/GDI主要部件的英文名称和有关术语 阅读并记住黑体字专业词汇；阅读EFI/GDI 原理图，提出疑难问题,
