汽车专业英语课件-5cha.ppt
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1、复习,提问EFI分类提问(教师说EFI系统汉语部件名称,同学回答英文名称)GDI原理,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,Diesel fuel systems and CR systemCooling,lubrication systems3.Emission control system,1.掌握柴油机喷油系统主要组成、CR系统部件的英文名称;掌握CR系统原理和排放系统控制原理2.了解冷却、润滑和排放控制系统的组成,1.重点为记忆英文专业术语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 Engine
2、2.8 Diesel Fuel Injection System,New Words and Phrases,Chapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System,Chapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System,Typical diesel system components include the fuel tank,fuel pump,fuel filter,injection pump,injectors,and t
3、he necessary fuel lines(Fig.2-18).The system in Fig.2-19 is typical of newer systems that utilize a computer-controlled electronic fuel injection pump.,2.8.2 Text,Chapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System,Fig2-18 A conventional diesel fuel injection system,Chapter 2 Intern
4、al Combustion Engine2.8 Diesel Fuel Injection System,Fig2-19.An computer controlled diesel fuel injection system with axial-piston distributor injection pump,Chapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System,Fuel Filter.Diesel fuel must be kept clean to avoid injector system troub
5、le.Very small particles are enough to clog injector nozzles.Diesel fuel systems typically use one or more filters to trap dirt and other deposits.Injection Pump.Due to the high compression(around 22:1)used in diesel engines,the diesel injection pump must be capable of producing high pressures.There
6、are a number of injection pump designs.The most commonly used automobile and light truck diesel injection pumps are classified as inline or distributor.The inline injection pump(Figure 12-18)uses a separate cylinder plunger-cam unit(Fig.2-20)for each cylinder.These units are contained in a straight
7、row in a common housing.,Chapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System,Figure 2-20.Pump plunger construction.When the control rack is moved,the plunger will be forced to rotate by the segmented gear sleeve acting on the plunger flange.,Chapter 2 Internal Combustion Engine2.8 D
8、iesel Fuel Injection System,Fig.2-21 Cutaway view of a distributor type injection pump.,The distributor injection pump is shown in Figure 2-21.You will note that a single,double-plunger type pump serves all injector outlets.A single delivery valve is located in the rotor.A distributor type fuel inje
9、ction pump witch is electronically controlled is shown in Fig.2-22.,Chapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System,Fig.2-22 A electronically controlled distributor type fuel injection pump.Fuel shutoff solenoid is controlled by the powertrain control module(PCM).When energized,
10、it is designed to completely stop the fuel flow into the injection pump.,Chapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System,Injector.There are many different injector designs,but all are a variation of two basic types-inward opening and outward opening.Diesel spray patterns will va
11、ry depending upon engine design.Glow Plug and Intake Air Heaters.To aid in igniting the compressed air-fuel mix during cold starting,diesel engines use glow plugs and intake air heaters.The glow plug is an electrically operated device that protrudes into the precombustion chamber.On later engines,th
12、e glow plugs are turned on and off automatically.Intake air heaters warm the air as it passes through on its way to the intake manifold.The heater element is a wire mesh that is electrically heated.The computer energizes the heater element before cranking.,Chapter 2 Internal Combustion Engine2.9 Com
13、mon rail injection systems,New Words and Phrases,Chapter 2 Internal Combustion Engine 2.9 Common rail injection systems,Newer diesel engines are equipped with common rail injection systems(Fig.2-23 to Fig.2-26).Common rail systems are direct injection(DI)systems.The injectors nozzles are placed insi
14、de the combustion chamber.The piston top has a depression where initial combustion takes place.The injector must be able to withstand the temperature and pressure inside the cylinder and must be able to deliver a fine spray of fuel into those conditions.These systems have a high pressure fuel rail c
15、onnected to individual injectors.,Text,Chapter 2 Internal Combustion Engine2.9 Common rail injection systems,The injectors are controlled by a computer that attempts to match injector operation to the operating conditions of the engine.There are two types of injectors:solenoid-type and piezoelectric
16、(Fig.2-27 and Fig.2-28).Newer diesel fuel injectors rely on stacked piezoelectric crystals rather than solenoids.Piezoelectric-crystals quickly expand when electrical current is applied to them.The crystals allow the injectors to respond very quickly to the needs of the engine.With this new-style in
17、jector,diesel engines are quieter,more fuel efficient,cleaner,and have more power.,Chapter 2 Internal Combustion Engine2.9 Common rail injection systems,Fig.2-23 Common rail(CR)system,Chapter 2 Internal Combustion Engine2.9 Common rail injection systems,Fig.2-24 Bosch third generation common rail wi
18、th piezoelectric inline injectors,Fig.2-25 Lucas diesel common rail(LDCR),2.9 Common rail injection systems,Fig.2-26 Common rail injection system as used with a V-8 engine,Fig.2-27 Solenoid-type injector,Chapter 2 Internal Combustion Engine2.9 Common rail injection systems,Fig.2-28 Boschs third gene
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