車輛工程外文翻譯---電動汽車新型動力系統(tǒng)的發(fā)展（英文）

1、ABSTRACTHonda has developed a powertrain for 2013 subcompact class EVs. This powertrain has both high power and low loss in order to provide the EV with better marketability than existing EVs, with the world-best energy

2、efficiency and class-exceeding dynamic performance. To achieve the energy efficiency, this powertrain also has a function of cooperative control with a newly developed electrically operated servo brake system. To achieve

3、 the high dynamic performance, a new rotor shape has been introduced to the electric motor, and the power control unit (PCU) is equipped with a high thermal conductivity heat sink. The battery system allows high output p

4、ower in a compact structure because of a triple parallel module group configuration and an air-cooling system. As a result of these innovations in the powertrain, the vehicle attains 82 miles of driving range while achie

5、ving world-leading energy efficiency of 29kWh/100 miles. It also has the acceleration performance equivalent to a two-liter gasoline-driven vehicle.INTRODUCTIONIn recent years, electric vehicles have been gathering incre

6、ased attention as a means of eliminating exhaust gas emissions from vehicles and reducing dependence on oil. In response to these needs, Honda released 100% electric- powered vehicles including the EV Plus electric vehic

7、le in 1997 and the FCX Clarity fuel-cell vehicle in 2009, based on the efforts of developing high-efficiency environmentally- friendly powertrains. The authors developed a powertrain for subcompact class EV that enables

8、the vehicle to have excellent energy efficiency and superior dynamic performance, by leveraging Honda's expertise of electric powertrains and energy management technology with the aim of reducing carbon dioxide

9、emission and effectively using alternative energy sources. This paper presents a detailedexplanation of the low-loss technology applied to this vehicle.COMPONENT AND PERCENTAGE OF EACH ENERGY LOSSFigure 1 shows energy lo

10、sses of the previous model EV. The losses include acceleration resistance, driving resistance, losses from system components including the motor and the charger, and losses of battery charging and discharging. In this de

11、velopment, improvements have been made with the aim of reducing overall losses by 40%. The following sections explain in detail the improvements made to reduce loss of each type.Figure 1. Losses in previous model EVDevel

12、opment of a New Powertrain for Subcompact Electric Vehicles2013-01-1478Published 04/08/2013Akira Kabasawa, Kenichiro Kimura, Takeshi Taguchi and Akihiro Anekawa Honda R&D Co., Ltd.Copyright © 2013 SAE Internat

13、ionaldoi:10.4271/2013-01-1478Downloaded from SAE International by North Carolina A-T University, Thursday, June 08, 2017limited. The developed model rapidly and accurately coordinates the braking torque produced by both

14、the hydraulic brakes and regenerative brakes, allowing more efficient use of regenerative energy. Figure 5 shows a schematic diagram depicting the operation of the electrically- operated servo brake system.Figure 5. Sche

15、matic diagram of electric servo brake systemFigure 6. Effect of electric brake servo systemIn this system, the operation of the pedal and the mechanism for applying the brake are independent. When the driver steps on the

16、 pedal, a stroke sensor produces a signal, the servomotor rotates in response to the signal and drives a ball screw, producing the same stroke as the driver's pedal movement. A brushless motor as the servo-motor and

17、a ball screw achieve highly precise fluid pressure control and a fast response. Through this mechanism, the brake is able to regenerate more energy over a course of driving than theprevious mechanisms, from the instant t

18、he driver presses the brake pedal right up to the instant the vehicle stops. This increases regenerative energy by approximately 8%. Figure 6 shows the effect of this system.REDUCTION OF DRIVING RESISTANCEFor reducing th

19、e driving resistance, the aerodynamic performance was improved. In comparison with the base model with an internal combustion engine, an EV requires much lower cooling performance of its powertrain. Therefore, reduction

20、of air resistance was enabled by reducing the air intake by 30%. Furthermore, a battery pack forming a flat underbody reduced an aerodynamic resistance since an EV no longer requires an exhaust pipe. Figure 7 shows the p

21、art that has been modified from the base model with an internal combustion engine. Thus we were able to improve 15% to air resistance coefficient.Figure 7. Improvement in aerodynamic resistanceREDUCTION OF BATTERY LOSSTh

22、ough the previous model used nickel-metal hydride batteries, the developed model adopts the lithium-ion batteries because of the higher energy density and higher charge/discharge efficiency. In spite of the energy densit

23、y and the efficiency, battery capacity fade has to be taken into account when using lithium-ion batteries as a vehicle energy source. Improvement of durability of the lithium-ion battery is described below.Improvement of

24、 Battery DurabilityOne of the factors that a lithium-ion battery degrades is the deposition of metallic lithium on the negative electrode. Potential difference between a positive electrode and a carbon negative electrode