Abstract: The society's concern for environment and energy saving has strongly promoted the development of hybrid electric vehicles. Firstly, this paper summarizes the development status of hybrid electric vehicles in Japan and the United States, introduces their development in Japan and the United States, and then selects the main commercial and conceptual hybrid electric vehicles, namely Honda Insight, Toyota Prius, Ford Prodigy, Daimler Chrysler ESX3 and GM Precept, and emphatically compares their technical parameters. Finally, the commercialization prospect and development trend of hybrid electric vehicles are prospected.
Keywords: Comparison of Hybrid Electric Vehicles
1 Introduction
Hybrid electric vehicle combines internal combustion engine, motor and battery with a certain capacity through control system. The motor can supplement the torque required when the vehicle starts and accelerates, and can also store and absorb the residual power of the internal combustion engine and the braking energy of the vehicle, thus greatly reducing fuel consumption and pollutant emissions. Although the hybrid electric vehicle has not achieved zero emission, its comprehensive indicators such as power, economy and emission can meet the current stringent requirements, and can alleviate the contradiction between automobile demand and environmental pollution and oil shortage. So since 1990s, there has been a storm of studying hybrid power all over the world. Toyota of Japan took the lead in commercializing hybrid vehicles, and 1997 launched the Prius. In the following period, many Japanese automobile companies realized the commercialization of various hybrid vehicles. In the United States, shortly after the Clinton administration took office, in order to develop a new generation of cars, the new generation of car partnership program PNGV was launched on September 29th, with the goal of developing a hybrid car with low fuel consumption. However, the plan was eventually abolished and failed to achieve the scheduled goal of launching commercial hybrid vehicles around 2005.
2 Development of Hybrid Electric Vehicles in Japan
2. 1 government development plan
Japan has the second largest number of cars in the world. Due to its dense population and small territory, 65,438+000% of its oil is imported. Therefore, Japan attaches great importance to the research and development of EV\HEV. As early as 1992, the Japanese government announced that it would allow 200,000 electric vehicles to be put on the market, but this did not happen. In July of 20001year, Japan launched the "Development and Popularization Action of Low-pollution Vehicles", which listed EV\HEV as one of the key low-pollution vehicles, and formulated special policies to promote the popularization and application of EV\HEV. In 2002, it was proposed that the tail gas emission should be greatly restricted from 2005, and the standard of "new long-term emission limit" was formulated, which was prepared to be used as the emission regulation for selling new cars after 2005. On February 26, 2002, a special committee in the field of atmospheric environment of Japan's Central Environmental Review Council (the advisory body of the Minister of the Environment) put forward a consultation proposal on the exhaust emission standards to be included in this regulation. The contents of the proposal include that compared with the current standards, the maximum reduction of particulate matter (PM) is 85%, and the maximum reduction of nitrogen oxides (nitrogen oxides) is 50%. The implementation of this regulation will further promote the development of EV\HEV. According to the current development speed, it is estimated that it will reach 265,438+10,000 vehicles in 20 10.
2.2 Work done by major automobile companies
1) Toyota
Toyota is the first manufacturer in the world to officially mass-produce hybrid vehicles. Since 1997, Prius has been sold in Japan, and since 2000, it has been sold in North America, Europe and all over the world. At present, the Prius has been listed in China. At 200 1, Toyota launched the Estima hybrid van, the weak hybrid crown luxury car and the Dyna hybrid light truck in Japan. Toyota has commercialized five models, and table 1 is the main hybrid model sold by Toyota.
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On1October 30th, 2005, 165438+ Toyota officially announced that the cumulative sales volume of Toyota hybrid vehicles exceeded 500,000. By the end of this year, the global sales volume has approached 5 13000. Table 2 shows the cumulative sales of Toyota hybrid vehicles:
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In order to improve the dynamic performance of vehicles under the premise of achieving low emissions, in 2003, Toyota introduced a new generation of hybrid cooperative drive to the second generation Prius. In 2005, he extended the application scope of this system to SUV models with higher power performance requirements-Lexus RX400h (called Harrier Hybrid in Japan) and Highlander Hybrid (called Kluger Hybrid in Japan).
2) Honda
In terms of hybrid vehicles, Honda currently sells two brands, namely INSIGHT launched by 1999 and Civic launched by 200 1. Honda is also pursuing power efficiency by studying new engines and nickel-hydrogen batteries in the development of hybrid vehicles; By developing new lightweight aluminum body and resin fuel tank, vehicles can reach the world's highest level of 35 kilometers per liter of gasoline, and vehicle exhaust emissions can reach the most stringent standards in the world.
3 Development of Hybrid Electric Vehicles in the United States
3. 1 government development plan
1973 the oil embargo imposed by the organization of petroleum exporting countries on western countries has sounded the alarm for the us government. 1976 President Carter signed the EV/HEV Research, Development and Demonstration Act, authorizing the US Department of Energy to implement and manage the EV/HEV research plan, but it was not until the early 1990s that the United States really started the research on electric vehicles. 1990 10 In October, President Bush signed the Clean Air Act, which strictly stipulated the vehicle emission standards. In the same month, the California government also formulated a new regulation requiring automakers to sell 2% of cars in California with zero emissions. At that time, only pure electric vehicles could meet the requirements of zero-emission vehicles.
199 1 1 In June, the American Advanced Battery Association was established, and its members included the three major American automobile manufacturers (Ford, General Motors and Chrysler), the American Electric Power Research Institute and the American Department of Energy, officially beginning a new era of joint development of electric vehicles by the government and enterprises. 1992, Massachusetts and New York officially adopted California's zero-emission vehicle regulations. In the same year, President Bush formally signed the energy policy bill, and the research and development of EV/HEV became an important part of this bill. According to this bill, the federal government allocated the first sum of money to the Ministry of National Defense for the development and demonstration of EV/HEV. 1993, the Clinton administration of the United States launched a new generation of car partnership program, that is, PNGV, requiring federal government departments to purchase a large number of alternative fuel vehicles including EV/HEV from 1993 to 1995. PNGV has formulated the development plan for 10, with the goal of 80mpg (about 3L/ 100km) of low fuel consumption vehicles.
On October 9th, 2002 10, before the end of the 10 plan, US Energy Secretary Spencer Abraham announced at the meeting attended by the heads of major automobile companies that according to President Bush's national energy plan, the United States decided to set up a new automobile research project called FreedomCAR, with long-term goals of high efficiency, low price and no pollution. Research advanced and efficient fuel cell technology, using hydrogen fuel as power, without any pollution. The reform project continues to carry out special research on electric vehicles, but the focus is on the development of hydrogen fuel cell electric vehicles.
3.2 PNGV concept car
According to the schedule of PNGV, 1999 is the stage of concentration and concentration technology, 1999 ~ 200 1 is the stage of concept car production, and 200 1 ~ 2005 is the stage of prototype car production. According to the above development schedule, the medium-term goal of PNGV has been achieved through the efforts of all participating units for six years. Ford and General Motors exhibited their diesel hybrid concept cars at the Detroit International Auto Show in 2000. On February 22nd of the same year, DaimlerChrysler unveiled its PNGV hybrid concept car at the National Museum in Washington. PNGV plan was terminated in 2002, because the goal of 80MPG was very high, and the new car developed did not achieve good results in cost, which could not meet the price requirements of users, that is, it did not have market value in a short time. More importantly, PNGV is still limited to using oil as the basic energy source. Therefore, new projects need to make new breakthroughs in this respect, focusing on the new generation of automobile energy, not limited to the existing technology and current fuel resources. However, PNGV has played the role of a global leader in EV/HEV technology development. From its establishment and implementation, the new generation automobile has become an important part of the strategic development of multinational automobile companies and industrial countries. In the next part of this paper, these three HEVs will be compared with Prius and Insight in detail.
4 Comparison of main hybrid electric vehicles in the United States and Japan
4. 1 comparison of basic parameters
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Figure 1 is the outline drawing of five HEVs in Japan and America, namely: ① insight; Introduced by Honda in Japan; (2) Prius; Introduced by Toyota in Japan; 3 Ford prodigy; ; ④ Daimler Chrysler ESX 3；; ⑤ Universal precepts. ① ② It is a commercial HEV, especially the Prius. At present, the global total sales volume has exceeded 300,000. ③ ④ ⑤ is the HEV concept car of PNGV project, which was introduced in the previous part of this paper. These five types of vehicles represent the highest development technology of HEV in Japan and the United States, and are the most representative. Table 3 lists the basic parameters of these five HEVs:
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Note: The fuel economy under the converted CAFE condition is the sum of 45% HWY condition and 55% urban condition, and the fuel economy of Precept is the best, reaching 80MPG (about 3L/ 100km).
4.2 Comparative analysis of fuel economy
Motor energy utilization ratio = electric energy consumed by pure electric drive/energy consumed by motor and internal combustion engine * * * is the same as working energy, and motor energy utilization ratio can also be understood as pure electric ratio. Figure 2 shows their motor energy utilization ratio. By comparing Figure 3, it can be found that the fuel economy of HEV is not directly related to the pure electricity ratio. Honda Insight, Daimler Chrysler ESX3 and Ford Prodigy are called light hybrid vehicles (MHEV) because their pure electric ratio is less than 23%. Toyota Prius and GM Prius account for more than 39%, so they are called heavy hybrid vehicles (FHEV).
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Fig. 3 compares the fuel economy of five HEVs, using the energy consumed per unit mass per unit mileage (UCE) in kj/km/kg. In addition, when testing fuel economy, each car has a load of 300 kg. Therefore, the UCE tested in this way can better reflect the economy of hybrid vehicles under heavy load.
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Figures 2 and 3 also roughly reflect the relationship between UCE and pure electric proportion. If these five vehicles are divided into two categories: gasoline vehicles and diesel vehicles, their fuel economy is directly proportional to the proportion of pure electric vehicles.
4.3 Fuel economy comparison with reference vehicles
These five HEVs are compared with the traditional diesel locomotive (CV) with the same power, and their fuel economy is analyzed. Select the following cars as the comparison benchmark: Toyota 1.8 liter Corolla, Honda CivicHX 1.6 liter, Ford Taurus 3.0 liter. Table 4 shows that they have achieved better fuel economy. Compared with CV, HEV improves fuel economy in the following three aspects:
A) More efficient fuel energy conversion (such as the improvement and transformation of the power system, the internal combustion engine always works in a medium load state);
B) Reduce the energy demand of automobiles (such as light weight and various resistances);
C) Take the method of braking energy storage to recover energy.
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In Table 4, compared with CV, the economy of HEV Prius and Insight is less than 65,438+000%, and that of PNGV concept car is more than 65,438+000%, especially Precept is 204.9%. Compared with Prius and Insight, PNGV concept car has achieved better fuel economy, because the goal of PNGV concept car is to pursue the highest fuel economy, regardless of the cost limit, adopting more new composite materials, reducing the weight of the car to a greater extent, and using EFI diesel engine to improve fuel economy. Prius and Insight are commercial HEVs, so fuel economy and cost should be considered comprehensively. Therefore, in terms of economy alone, PNGV's concept car is better.
5 concluding remarks
Advanced and practical hybrid technology has obvious energy-saving and environmental protection effects. Adopting hybrid electric vehicle is the most practical solution to environmental protection and energy problems at present. However, the hybrid electric vehicle can only meet the basic requirements of environmental protection at the expense of some environmental benefits, so structurally, two systems of battery/motor and internal combustion engine are installed on the vehicle with only one system, which not only increases the weight of the vehicle itself, but also improves the requirements for the overall process and control. Besides being limited by the current battery technology like the pure electric vehicle (BEV), the energy source of hybrid power is still oil, which determines that hybrid power is not the final form of the development of electric vehicles. The cancellation of PNGV plan and FreedomCAR plan in the United States focuses on the development of fuel cell vehicles, which illustrates this point.
However, the current hot sales of hybrid electric vehicles by several major Japanese companies show that hybrid electric vehicles are the automobile technology in the transition from the traditional automobile era to the hydrogen fuel cell vehicle era. Although it is not a long-term solution, it is estimated that there will be a long market cycle of more than 20 years. It can make full use of the existing diesel locomotive production capacity and promote the transformation and development of the traditional automobile industry.
In a word, hybrid electric vehicle is between traditional automobile, pure electric vehicle and fuel cell vehicle, and it is an electric vehicle product with mature economy and technology.
Comparison of Hybrid Electric Vehicles between America and Japan
Abstract: People pay more and more attention to environmental pollution and energy conservation. This paper briefly reviews the development status of hybrid electric vehicles in the United States and Japan. Then, we choose two commercial gasoline hybrid vehicles (Toyota Prius and Honda Insight) and three PNGV diesel hybrid prototypes (Ford Prodigy, GM Precept and DaimlerChrysler ESX3) and compare their characteristics. Finally, we discuss and predict the future of hybrid electric vehicles in commercial production.
Keywords: HEV electric vehicle comparison
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