汽車專業(yè)英語(yǔ)課件(宋進(jìn)桂)Chapter2-7

1、Chapter 2 Internal Combustion Engine2.7 Gasoline direct injection New Wordsdrasticdrstika.劇烈的，猛烈的劇烈的，猛烈的responserispnsn.反應(yīng)，響應(yīng)反應(yīng)，響應(yīng)efficiencyifinsin.效率，效能，有效性效率，效能，有效性u(píng)ltra-leanltrli:na.極端稀薄的，超稀薄極端稀薄的，超稀薄deploydipliv.展開(kāi)，部署展開(kāi)，部署homogeneous?hmi:njsa.相似的，均勻的相似的，均勻的stratifystrtifaia. (使使)成層，（使）分層成層，（使）分層

2、 Chapter 2 Internal Combustion 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 lowe

3、ring fuel consumption and increasing 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.

4、 This is accomplished by enabling 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 thro

5、ughout the world in passenger cars. Chapter 2 Internal Combustion 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 outp

6、ut. This is achieved with the 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-le

7、an Combustion Mode. Under 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-

8、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 homogeneous, cooler a

9、ir-fuel mixture which minimizes the possibility 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 FS

10、Is fuel-saving potential is shown in Figure 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

11、 Internal Combustion Engine2.7 Gasoline direct injection Fig.2-17 Gasoline direct injection systemChapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System particlep:tikln.微粒，顆粒微粒，顆粒clogklgv.&n.阻塞，堵塞阻塞，堵塞nozzlenz()ln.噴嘴噴嘴traptrpn.圈套，陷阱，捕集器圈套，陷阱，捕集器plungerplnn.柱塞，活塞柱塞，活塞rackrkn.齒條齒條bar

12、relbr()ln.桶；桶；v.裝入桶內(nèi)裝入桶內(nèi)helixhi:liksn.螺旋，螺旋狀物螺旋，螺旋狀物New WordsChapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System New Wordsvariationverieinn.變化，變更，變種，變調(diào)變化，變更，變種，變調(diào)solenoidsulinidn.螺線管，電磁線圈螺線管，電磁線圈鐵，閥，開(kāi)關(guān)鐵，閥，開(kāi)關(guān)shutofft:fn.中斷，切斷，關(guān)閉中斷，切斷，關(guān)閉energizeendaizv.供給供給能量，通電，勵(lì)磁能量，通電，勵(lì)磁 Chapter 2 I

13、nternal Combustion Engine2.8 Diesel Fuel Injection System 2.8.1 Conventional SystemTypical diesel system components include the fuel tank, fuel pump, fuel filter, injection pump, injectors, and the necessary fuel lines (Fig.2-18). The system in Fig.2-19 is typical of newer systems that utilize a com

14、puter-controlled electronic fuel injection pump. Chapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System Fig2-18 A conventional diesel fuel injection system Chapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System Fig2-19. An computer controlled diesel fuel injection system

15、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 trouble. Very small particles are enough to clog injector nozzles. Diesel fuel systems typically use one or more filt

16、ers 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 are a number of injection pump designs. The most commonly used automobile and light truck diesel injecti

17、on 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 row in a common housing. Chapter 2 Internal Combustion Engine2.8 Diesel Fuel Injection System Figur

18、e 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 Diesel Fuel Injection System Fig.2-21 Cutaway view of a distributor type injection pump. The dist

19、ributor The distributor injection pump is shown injection pump is shown in Figure 2-21. You in Figure 2-21. You will note that a single, will note that a single, double-plunger type double-plunger type pump serves all pump serves all injector outlets. A injector outlets. A single delivery valve sing

20、le delivery valve is located in the rotor. is located in the rotor. A distributor type fuel A distributor type fuel injection pump witch is injection pump witch is electronically electronically controlled is shown in controlled is shown in Fig.2-22.Fig.2-22. Chapter 2 Internal Combustion Engine2.8 D

21、iesel 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, it is designed to completely stop the fuel flow into the injection pump. Chapter 2 Internal Combustion En

22、gine2.8 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 vary depending upon engine design.Glow Plug and Intake Air Heaters.To aid in igniting the compressed air

23、-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, the glow plugs are turned on and off automatically. Intake air heaters warm the air as it passes thr

24、ough 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 Common rail injection systems piezoelectricpaii:zuilektrika.壓電的壓電的efficientifinta.有效的，效率高的有效的，效率高的N

25、ew Words 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 inside the combustion chamber. The pist

26、on 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 connected to individual injectors

27、. 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 (Fig. 2-27 and Fig.2-28). Newer diesel fuel injectors rely on stacked piezoelectric