外文翻譯---混合動(dòng)力電動(dòng)汽車(chē)機(jī)械和再生制動(dòng)的整合-汽車(chē)設(shè)計(jì)-文庫(kù)吧
2025-04-17 09:10 本頁(yè)面
【正文】 braking torque depending on driver demand and should be able to do so smoothly and safely. Controlling the regenerative braking torque can be done using control algorithms and vector control for induction motors. However, controlling the mechanical braking torque independently of the driver pedal force, while maintaining proper safety backups, proved to be more of a challenge. To overe this problem, a system was developed that would attenuate the pressure in the brake booster in order to control the amount of mechanical torque developed by the braking system． Hybrid Electric Vehicle Overview Hybrid vehicles have emerged as one of the short term solutions for reducing vehicle emissions and improving fuel economy. Over the past 10 years almost all of the major automotive panies have developed and released for sale their own hybrid electric vehicles to the public. The popularity of hybrid electric vehicles has grown considerably since the turn of the century. With enormous pressure to bee more environmentally friendly and with unpredictable gas prices, the sales of hybrid electric vehicles have increased dramatically in recent years. Hybrid Configurations For the past 100 years the objective of the hybrid has been to extend the range of electric vehicles and to overe the problem of long recharging times [35]. There are three predominant hybrid electric vehicle configurations currently on the market today. These configurations are known as series hybrids, parallel hybrids and 4 series/parallel hybrids. Each configuration has its advantages and disadvantages which will be discussed in the following sections. Series Hybrids In series hybrids the mechanical output from the internal bustion engine is used to drive a generator which produces electrical power that can be stored in the batteries or used to power an electric motor and drive the wheels. There is no direct mechanical connection between the engine and the driven wheels. Series hybrids tend to be used in high power systems such as large trucks or lootives but can also be used for lower power passenger vehicles [18]. The mechanically generated electrical power is bined with the power from the battery in an electronic controller. This controller then pares the driver demand with the vehicle speed and available torque from the electric motor to determine the amount of power required from each source to drive the vehicle. During braking, the controller also switches the power electronics to regenerative mode, and directs the power being regenerated to the batteries [55]. There are many advantages made possible by the arrangement described above. It is possible to run the ICE constantly at its most efficient operating point and share its electrical output between charging the battery and driving the electric motor. By operating the engine at its most efficient operating point, emissions can be greatly reduced and the most electrical power can be generated per volume of fuel. This configuration is also easierto implement into a vehicle because it is less plex which makes this method more cost effective. Parallel Hybrids In parallel hybrid configurations the mechanical energy output from the ICE is transmitted to a gearbox. In this gearbox the energy from the ICE can be mechanically bined with a second drive from an electric motor. The bined mechanical output is then used to drive the wheels [35]. In this configuration there is a direct connection between the engine and the driven wheels. As in series hybrids the controller pares the driver demand with the vehicle speed and output torque and determines the amount of power to be used from each source to meet the demand, 5 while obtaining the best possible efficiency. A parallel hybrid also controls regenerative braking similarly to a series hybrid. Parallel hybrids are usually used in lower power electric vehicles in which both drives can be operated in parallel to provide higher performance [18]. There are a number of advantages of a parallel hybrid over a series hybrid. The most important advantage is that since only one conversion between electrical and mechanical power is made, efficiency will be much better than the series hybrid in which two conversions are required. Since the parallel hybrid has the ability to bine both the engine and electric motor powers simultaneously, smaller electric motors can be used without sacrificing performance, while getting the fuel consumption and emission reduction benefits. Lastly, parallel hybrids only need to operate
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