Gasoline Direct Injection and Throttle-by-Wire Technology

1. UNIT 4GASOLINE FUEL INJECTIONTEXT AGasoline Direct Injection (GDI) and Throttle-by-wire PROFESSIONAL ENGLISH

2. UNIT 3 GASOLINE FUEL INJECTION TEXT A Gasoline Direct Injection (GDI) and Throttle-by-wire Gasoline Direct Injection Mitsubishi GDI Volkswagen AG's direct-injection (FSI) Toyota DI engine Electronic Throttle—Throttle-By-Wire 本次课学习内容

3. 本次课学习目标 • 掌握GDI系统的特点 • 掌握GDI系统的原理 • 掌握电子节气门原理

4. NEW WORDS drastic ['dræstik] a. 激烈的，猛烈的 GDI=gasoline direct injection(汽油直接喷射) forerunner ['fɔ:rʌnə] n.先驱（者），先锋，祖先 CVT=continuously variable transmission（无级变速器） characteristics [kæriktə'ristiks] n.特性（曲线） exotic [ig'zɔtik] n.奇异的，外来的，异国情调的 FSI=fuel straight injection燃油直接喷射 layout ['leiaut] n.规划，设计（图案），布置 stick [stik] n.棒，棍；v.粘住，粘铁 estate [i'steit] n.状态，时期，不动产

5. signature ['signət∫ə] n.签名，署名，信号 acronym ['ækrənim] n.只取首字母的缩写 linchpin [‘lint∫pin] n.关键 justice ['ʤʌstis] n.正义，正当，公平，欣赏，审判 effervescent [efə'vesənt] a.冒泡的，兴奋的 superb [sju:'pə:b] n.壮丽的，华美的，最上等的，无比的 drawback ['drɔ:bæk] n.缺点，障碍 brilliant ['briliənt] a.灿烂的，闪耀的 DI=direct injected, direct injection 直接喷射 crucial ['kru:∫(ə)l] a.至关紧要的 nitrogen ['naitrəʤ(ə)n] n.氮 lean-burn ['li:n-bə:n] a.稀薄燃烧

6. incorporate[in'kɔ:pəreit] v.合并，混合，组成公司；a.合并的，一体化的 lip [lip] n.嘴唇，唇缘 helical ['helik(ə)l] a.螺旋状的 quintessential [kwinti'sen∫əl] a.精髓的，精萃的，典范的，本质的 stratify ['strætifai] v.使成层 promote [prə'mout] v.促进，加速，激励，提升 vicinity [vi'siniti] n.附近，临近，接近 coincidental [kouinsi'dent(ə)l] a.一致的，符合的，巧合的 purify [‘pjuərifai] v.净化，使纯净 occlude [ə‘klu:d] v.使闭塞，吸收 stoichiometric [stɔikiə‘metrik] a.化学当量的，理想配比的

7. homogeneous [ֽhɔmə'ʤi:njəs] a.相似的，均匀的 crossover ['krɔsouvə] n.跨越，交叉，交迭，穿过 throttle-by-wire ['rɔtl-bai-'waiə] 线控节气门 servomotor ['sə:voumoutə] n. 伺服电动机，辅助电动机，伺服传动装置 ASR =anti-slip regulator或acceleration slip regulation 防滑调节装置 ABS =anti-lock braking system防抱死制动系统 takeoff ['teikɔf] n.起飞，开始 beat [bi:t] n.敲打，拍子; v.打，打败 trust [trʌst] v. & n.信任，信赖 limp-home [limp-'houm] n.跛行回家

8. PHRASES AND EXPRESSIONS make up 补充，修理，整理，形成 all but 几乎，差不多 turbo lag 增压滞后 in conjunction with 连同…一起 volumetric efficiency 容积效率 VVT-i (Variable Valve Timing, intelligent) 智能型可变气门定时 cruise control 巡航控制 traction control 牵引控制 lay down 设计，制定，主张

9. Gasoline Direct Injection (GDI) and Throttle-by-wire Gasoline Direct Injection Conventional gasoline engines are designed to use an electronic fuel injection system, replacing the traditional mechanical carburetion system. Multi-point injection (MPI), where the fuel is injected through each intake port, is currently one of the most widely used systems [1]. 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 response time and combustion efficiency, while lowering 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.

10. Direct injection is designed to allow greater control and precision, resulting in better fuel economy. 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 throughout the world in passenger cars.

11. Mitsubishi GDI Mitsubishi Motors is aiming to achieve both low fuel consumption and high output. MMC is a world forerunner in the development of direct cylinder injection gasoline engines, known as "GDI", which were first introduced in the 1996 Galant . GDI supplies fuel directly to the inside of the cylinder. A variety of air-fuel mixtures can be created according to changes in the fuel injection timing. Using methods and technologies unique to Mitsubishi, the GDI engine provides both lower fuel consumption and higher output. This seemingly contradictory and difficult feat is achieved with the use of two combustion modes. Put another way, injection timings change to match engine load.

12. Ultra-lean 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-lean air-fuel ratio of 30: 40 (35:55, including EGR). 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 possibility of engine knocking. These two modes are represented in Figure 4-1. The piston of the GDI engine is shown in Figure 4-2.

13. Fig. 4-1 Two combustion modes of the GDI

14. Fig.4-2 A piston of Mitsubishi GDI engine

15. In addition, the GDI-CVT introduced in the 2000 Lancer significantly reduces energy loss by integrated control that makes the most of GDI characteristics [3]. High-precision torque control and large range for low fuel consumption as well as the CVT characteristics of quick and continuous control of the large gear change ratios enable top class level fuel economy and an exceptionally smooth ride [4]. Volkswagen AG's direct-injection The Audi's new 2L I-4 improves greatly on the high standards set by the 1.8T it replaces. While the Audi misses the exotic 5-valve-per-cylinder configuration of the 1.8T, the 2L FSI makes up for its more-conventional 4-valve layout by sticking a fuel injector into the combustion-chamber, real estate that used to be occupied by Audi's signature fifth valve.

16. Direct injection gasoline (DIG) technology is the fastest-emerging power and economy enhancing innovation in the powertrain sector and with the 2L FSI (Volkswagen AG’s direct-injection acronym for Fuel Straight Injection), Audi and its VW parent is leading the pack. Audi says FSI will be its gasoline-engine linchpin going into the future. Soon, every Audi-brand engine will feature the FSI system. FSI adds new levels of power and torque, yet also delivers fuel-economy gains that, at the least, offset what typically would be lost in generating increased power. For example, although the 2L FSI develops 30 hp and 40-plus lb-ft. (41 Nm) more torque than the smaller 1.8T (as used by Audi), a continuously variable transmission-equipped A4 with the new engine gets 20% better fuel economy in city driving and does 10% better on the highway.

17. The numbers don't do justice to the effervescent nature of the new I-4. The throttle response is the last word in immediate, and this is one of those rare 4-cyls. That continually hits the fuel cutoff long before noise and vibration suggest a gear change is in order. Twin balance shafts certainly help in that regard. The 2L mill has a variable-length intake manifold and a superb BorgWarner Turbo Systems variable-turbine turbocharger that, when combined with FSI, all but eliminates turbo lag, just about the last remaining drawback of turbocharging. The 2L I-4 is claimed to be the world's first automotive engine to combine DIG technology and turbocharging. If Audi's brilliant new 4-cyl. engine is typical of what happens when direct injection and turbocharging get together, we expect to see much of the auto industry follow in Audi's innovative footsteps.

18. Toyota DI engine Toyota Motor Corp. has developed a 4-stroke, direct-injected (DI) gasoline engine. In conjunction with the new DI engine is another crucial item: a production-ready 3-way exhaust catalyst capable of oxidizing the oxides of nitrogen (NOX)-rich exhaust inherent to lean-burn engines. The new engine, designated D-4 by Toyota, is a 2L DOHC inline 4-cyl. Compression ratio is 10:1, and the engine operates efficiently on regular unleaded gasoline. The D-4 incorporates a highly optimized combustion chamber: The piston crowns are fitted with a lipped, cup-like formation that focuses the injected air/fuel mixture tightly around the spark plug for maximum burn. Intake air is drawn through helical ports that create a high degree of horizontal swirl, which Toyota says combines with the lipped combustion chamber to not only maintain highly stable combustion—a quintessential problem for lean-burners—but also to stratify the air/fuel mixture.

19. Additional swirl is promoted with special swirl-inducing high-pressure injectors. The end result is a fuel-rich mixture in the direct vicinity of the spark plug, with extremely lean air/fuel ratios near the cylinder walls. The D-4 can operate stably with air/fuel ratios as high as 50:1, compared with the company's existing indirect-injected lean-burn engine that operates with maximum air/fuel ratios of roughly 24:1. Toyota says a coincidental advantage of the highly stratified charge employed in the new engine is a cooler air charge, due to increased fuel vaporization. The cooler charge increases volumetric efficiency, and the engine also is fitted with the company's VVT-i (Variable Valve Timing, intelligent) system to precisely control each cylinder's intake event.

20. Lean-burn engines are known for their characteristic high levels of NOX emissions. The company says the new D-4 uses a high degree of exhaust gas recirculation (EGR)--as much as 40% when the engine operates in the lean-combustion mode--and the natural EGR-like operation of the VVT-i system to drastically reduce NOX production. The new 3-way catalyst uses a storage/reduction design to purify occluded NOX at the stoichiometric level -- when the engine operates in lean modes, excess NOX is stored until it can be combined/purified with exhaust gases produced during stoichiometric operation. The new engine relies on powerful, precise engine-management software to accurately tailor fuel-injection timing and duration. At high loads, such as during heavy acceleration, fuel is injected earlier in the compression stroke, creating a homogeneous mixture and optimum power.

21. Crossover points between homogeneous and stratified mixtures produce semi-stratified air/fuel mixture for "smooth torque transition." Torque production in the low- and middle-speed ranges is improved by 10% over conventional engines, while fuel economy in the Japanese 10-15 urban fuel economy test is improved by a significant 30% or better. Moreover, Toyota claims the quicker response presented by the DI design improves 0 to 62 mph (0-100 km/h) and passing acceleration times by 10%.

22. Electronic Throttle—Throttle-By-Wire Some of the newest Motronic systems have an electronic throttle (also known as a throttle-by-wire system). The electronic throttle has no mechanical link between the accelerator pedal and the throttle valve. Instead, as shown in Fig.4-3, an accelerator sensor picks up your movement or position of the accelerator pedal. It signals the control unit about pedal movement, and the control unit signals the servomotor on the throttle shaft to open. The electronic throttle (Bosch calls it EGAS) may sound like something none of us needs, but it has many benefits.

23. Fig. 4-3 Electronic throttle sends accelerator signal to Motronic control unit DC motor moves throttle valve, modified by engine temperature, idle rpm, and maximum rpm

24. The throttle opening signal may be modified according to engine rpm and engine temperature. It can provide simplified cruise control. It can also control minimum rpm, replacing the idle-speed stabilizer, and control maximum rpm, replacing the alternate-injector cut-out. But there's more. For traction control, the electronic throttle links with the ABS (Anti-lock Braking System). The same wheel-speed sensors of ABS also feed the ASR (Anti-Slip Regulator). When any driving wheel starts to slip, a slight brake application prevents that wheel from slipping so much that the differential delivers no power to the other driving wheel. If both driving wheels show signs of slipping, the electronic throttle cuts back power for maximum traction. Traction control gives the car the max acceleration the tires can deliver to the road. If laying down tire smoke is your thing, avoid ASR. But for making the fastest takeoff, you cannot beat it.

25. Can you trust the electronic throttle? Will it provide unintended acceleration? The system checks its safety circuits before start-off, and reports defects to the driver. If a defect is found, a limp-home circuit may disable some of the functions, but it will allow you to get to the house or the shop. It may well be more reliable than some cable actuated throttles.

26. 小结  Gasoline Direct Injection Advantages  Mitsubishi GDI Volkswagen AG's direct-injection(FSI) Toyota DI engine Electronic Throttle—Throttle-By-Wire

27. 作业 • 熟记相关专业词汇 • P84 EXERCIES Ⅰ& Ⅱ