外文翻譯--燃油噴射系統(tǒng)

附 錄 附錄 A 英文文獻與中文參考譯文 A1Fuel injection systems A1.1 General information Fuel injection systems have been used on vehicles for many years. The earliest ones were purely mechanical. As technology advanced, electronic fuel injection systems became more popular. Early mechanical and electronic fuel injection systems did not use feedback controls. As emissions became more of a concern, feedback controls were adapted to both types of fuel injection systems. Both mechanical and electronic fuel injection systems can be found on gasoline engines. A1.2 Multi-port fuel injections This is the most common type of fuel injection system found today. Regardless of the manufacturer, they all function in the same basic way. On these systems an equal amount of fuel is delivered to each cylinder. These systems all use sensors which transmit operating conditions to the computer. Information from these sensors is processed by the computer which then determines the proper air/fuel mixture. This signal is sent to the fuel injectors which open and inject fuel into their ports. The longer the injector is held open, the richer the fuel mixture will be. Most fuel injection systems need the following information to operate properly. Temperature sensors-this includes both air and coolant temperature. The computer determine how rich or lean the mixture should be. The colder the temperature, the richer the mixture. Throttle position sensors or switches-the computer uses this information to determine the position of the throttle valve(s). Some vehicles use sensors which relay the exact position of the throttle valve(s) at all times. Others use switches which only relay closed and wide-open throttle positions (some may also use a mid-throttle switch). These switches and sensors help determine engine load. Airflow sensors-these sensors also help the computer determine engine load by indicating the amount of air entering the engine. There are several different types of airflow sensors, but in the end, they all do the same job. Manifold pressure sensors-if a vehicle is not equipped with an airflow sensor, it uses a manifold pressure sensor to determine engine load (Note that some vehicles with an airflow sensor may also have a manifold pressure sensor. This is used as a fail-safe if the airflow sensor fails). As engine load increases, so does intake manifold air pressure. Engine speed and position sensors-engine speed/position sensors can be referenced form the crankshaft, camshaft or both. In addition to helping determine engine load, these sensors also tell the computer when the injectors should be fired. These systems operate at a relatively high pressure(usually at least 30 psi). To control the fuel pressure, a fuel pressure regulator is used. As engine load increases, more fuel pressure is needed. This is due to the richer mixture (more fuel needed) and to overcome the increased air pressure in the ports. Any unused fuel is diverted back to the fuel tank using a return line. A2. Ignition system There are many different types of ignition systems. Most of these systems can be placed into one of three distinct groups: the conventional breaker point type ignition systems (in use since the early 1900s)； the electronic ignition systems (popular since the mid 70s)； and the distributorless ignition system (introduced in the mid 80s). The automotive ignition system has two basic functions: it must control the spark and timing of the spark plug firing to match varying engine requirements, and it must increase battery voltage to a point where it will overcome the resistance offered by the spark plug gap and fire the plug. A2.1How does the ignition system work An automotive ignition system is divided into two electrical circuitsthe primary and secondary circuits. The primary circuit carries low voltage. This circuit operates only on battery current and is controlled by the breaker points and the ignition switch. The secondary circuit consists of the secondary windings in the coil, the high tension lead between the distributor and the coil (commonly called the coil wire) on external coil distributors, the distributor cap, the distributor rotor ,the spark plug leads and the spark plugs. The distributor is the controlling element of the system. It switches the primary current on and off and distributes the current to the proper spark plug each time a spark is needed. The distributor is a stationary housing surrounding a rotating shaft. The shaft is driven at one-half engine speed by the engines camshaft through the distributor drive gears. A cam near the top of the distributor shaft has one lobe for each cylinder of the engine. The cam operates the contact points, which are mounted on a plate within the distributor housing. A rotor is attached to the top of the distributor shaft. When the distributor cap is in place, a spring-loaded piece of metal in the center of the cap makes contact with a metal strip on top of the rotor. The outer end of the rotor passes very close to the contacts connected to the spark plug leads around the outside of the distributor cap. The coil is the heart of the ignition system. Essentially, it is nothing more than a transformer which takes the relatively low voltage (12 volts) available from the battery and increases it to a point where it will fire the spark plug as much as 40000 volts. The term “coil” is perhaps a misnomer since there are actually two coils of wire wound about an iron core. These coils are insulated from each other and the whole assembly is enclosed in an oil-filled case. The primary coil, which consists of relatively few turns of heavy wire, is connected to the two primary terminals located on top of the coil. The secondary coil consists of many turns of fine wire. It is connected to the high-tension connection on top of the coil (the tower into which the coil wire from the distributor is plugged). Under normal operating conditions, power from the battery is fed through a resistor or resistance wire to the primary circuit of the coil and is then grounded through the ignition points in the distributor (the points are closed). Energizing the coil primary circuit with battery voltage produces produces current flow through the primary windings, which induces a very large, intense magnetic field. This magnetic field remains as long as current flows and the points remain closed. As the distributor cam rotates, the points are pushed apart, breaking the primary circuit and stopping the flow of current. Interrupting the flow of primary current causes the magnetic field to collapse. Just as current flowing through a wire produces a magnetic field, moving a magnetic field across a wire will produce a current. As the magnetic field collapses its lines of force cross the secondary windings, inducing a current in them. Since there are many more turns of wire in the secondary windings, the voltage from the primary windings is magnified considerably up to 40000 volts18,19. 參考譯文： A1.燃油噴射系統(tǒng) A1.1 燃油噴射系統(tǒng)概述 燃料噴射系統(tǒng)已經(jīng)在汽上車使用了許多年。最早的部分是純粹機械的。對于先進的技術(shù)，電子燃料噴射系統(tǒng)變得更加普遍。早期的機械式和電子式燃料噴射系統(tǒng)沒有使用反饋控制。當今與排放越來越相關(guān)，兩種燃油噴射系統(tǒng)反饋控制都適應(yīng)。機械和電子式燃料噴射系統(tǒng)在汽油發(fā)動機上比較長見。 A1.2多點燃油噴射 系統(tǒng) 這是今天被使用的燃料噴射系統(tǒng)中最普通的類型。所有的制造商，他們都使用同一個基本的方式。它是將等量的混合氣分配到各個氣缸中。 燃油系統(tǒng)都是通過傳感器輸送的信號給計算機控制。通過計算機處理傳感器的信號，然后確定適當?shù)目杖急?。然后將噴油信號送給噴油器，控制噴油器的開啟和關(guān)閉。噴油器打開的時間越長，進入氣缸的混合氣越多。大部分燃油噴射系統(tǒng)需要以下傳感器信號正常運作。 溫度傳感器，這里面包括空氣和冷卻液的溫度。計算機通過溫度傳感器來確定混合氣的濃度。低溫時，使混合氣變濃。 節(jié)氣門位置傳感器，電腦根據(jù)此信號來確定 節(jié)氣門的開閉。一些車輛在任何時候都使用節(jié)氣門位置傳感器，從而確定節(jié)氣門的具體位置。其他車輛使用傳感器確定節(jié)氣門關(guān)閉和節(jié)氣門打開位置（有些還可以使用怠速開關(guān)）。這些開關(guān)和傳感器，幫助確定發(fā)動機負荷。 空氣流量傳感器，該傳感器還有助于計算機確定發(fā)動機的進氣量，用于表示發(fā)動機負荷。有幾種不同類型的空氣流量計，不過，他們的作用是相同的。 進氣壓力傳感器，如果車輛沒有配備空氣流量傳感器，則它采用了進氣壓力傳感器，以確定發(fā)動機負荷（請注意，一些車輛的空氣流量傳感器也可能有進氣壓力傳感器。這是作為一個空氣流量傳感器故障的 后備安全故障）。進氣歧管空氣壓力增大則表示發(fā)動機負荷增大。 發(fā)動機的 轉(zhuǎn)速 和位置傳感器，發(fā)動機轉(zhuǎn)速 和 位置傳感器可 從 曲軸 、 凸輪軸 得到信號 。除了 可以 確定發(fā)動機負荷， 還可以通過傳感器確定進氣量 。 燃油噴射 系統(tǒng) 工作 在一個相對較高的壓力（通常至少 30 磅） 環(huán)境下 。燃油壓力調(diào)節(jié)器 用來 控制燃油壓力 ，使燃油壓力保持恒定 。 如果 發(fā)動機負荷增加，更省油的壓力是必要的。 這是由于混合氣變濃 （需要更多的燃料），并克服空氣壓力。任何未使用的燃料 都通過回油管 回到油箱。 A2點火系統(tǒng) 點火系統(tǒng)有許多不同類型。大多數(shù)點火系統(tǒng)可分為三種：傳統(tǒng)的斷路 器點火系統(tǒng)（自 20 世紀初期以來使用）；電子點火系統(tǒng)（流行于 70 年代中期）和微機控制點火系統(tǒng)（發(fā)展于 80年代中期）。 汽車點火系統(tǒng)有兩個基本功能，首先它必須能夠控制火花的大小和點火時刻，以配合不同發(fā)動機的要求；其次它必須能夠增加電池電壓以克服火花塞兩極間的電阻來產(chǎn)生火花。 A2.1點火系統(tǒng)如何工作 點火系統(tǒng)電路由兩部分組成 初級電路和次級電路。次級電路承載著較低的電壓。電池電流從該電路流過，并由斷電器和點火開關(guān)控制通斷。次級電路由火花塞、高壓線、分電器分火頭、次級點火線圈組成。 分電器是點火系統(tǒng)的控制部分。它 將初級電流接通或斷開，并將電流送到相應(yīng)的火花塞上。分電器軸以低于曲軸一半的轉(zhuǎn)速旋轉(zhuǎn)。分電器軸附近的凸輪軸有一個凸起對應(yīng)著相應(yīng)的汽缸。 轉(zhuǎn)子連接在分電器軸的頂部。當分火頭置位時，一個彈簧擠壓著金屬塊使之與轉(zhuǎn)子上的金屬帶連接。轉(zhuǎn)子的尾端與火花塞末端緊密連接使之發(fā)火。 點火線圈是點火系統(tǒng)的核心。從本質(zhì)上講，它只不過是一個變壓器，將電池的低電壓