【正文】 aster the car moves, the faster the governor spins. Inside the governor is a springloaded valve that opens in proportion to how fast the governor is spinning the faster the governor spins, the more the valve opens. Fluid from the pump is fed to the governor through the output shaft. The faster the car goes, the more the governor valve opens and the higher the pressure of the fluid it lets through. Valves and Modulators Throttle Valve or Modulator To shift properly, the automatic transmission has to know how hard the engine is working. There are two different ways that this is done. Some cars have a simple cable linkage connected to a throttle valve in the transmission. The further the gas pedal is pressed, the more pressure is put on the throttle valve. Other cars use a vacuum modulator to apply pressure to the throttle valve. The modulator senses the manifold pressure, which drops when the engine is under a greater load. Manual Valve The manual valve is what the shift lever hooks up to. Depending on which gear is selected, the manual valve feeds hydraulic circuits that inhibit certain gears. For instance, if the shift lever is in third gear, it feeds a circuit that prevents overdrive from engaging. Shift Valves Shift valves supply hydraulic pressure to the clutches and bands to engage each gear. The valve body of the transmission contains several shift valves. The shift valve determines when to shift from one gear to the next. For instance, the 1 to 2 shift valve determines when to shift from first to second gear. The shift valve is pressurized with fluid from the governor on one side, and the throttle valve on the other. They are supplied with fluid by the pump, and they route that fluid to one of two circuits to control which gear the car runs in. 外文資料 10 The shift valve will delay a shift if the car is accelerating quickly. If the car accelerates gently, the shift will occur at a lower speed. Let39。s a speed increase. In this transmission, engaging the overdrive acplishes two things at once. If you read How Torque Converters Work, you learned about lockup torque converters. In order to improve efficiency, some cars have a mechanism that locks up the torque converter so that the output of the engine goes straight to the transmission. In this transmission, when overdrive is engaged, a shaft that is attached to the housing of the torque converter (which is bolted to the flywheel of the engine) is connected by clutch to the pla carrier. The small sun gear freewheels, and the larger sun gear is held by the overdrive band. Nothing is connected to the turbine。ve probably never tried driving a manual transmission car using only third gear. If you did, you39。ll start with the key to the whole system: plaary gear sets. Then we39。 but because that clutch is released, the bigger sun gear is free to spin in the opposite direction of the turbine Second Gear This transmission does something really neat in order to get the ratio needed for second gear. It acts like two plaary gear sets connected to each other with a mon pla carrier. The first stage of the pla carrier actually uses the larger sun gear as the ring gear. So the first stage consists of the sun (the smaller sun gear), the pla carrier, and the ring (the larger sun gear). The input is the small sun gear。 without them, many hoses would be needed to connect the various parts of the transmission. First, we39。 雖然自動(dòng)變速器 (加上它的扭矩變換器 ) 和一個(gè)手動(dòng)變速器 (借由它的離合器 ) 完成同樣的工作 , 但是他們操作方法完全不同。如果你嘗試過，你很