Classification of new energy vehicles

The new energy vehicle refers to an automobile that adopts advanced technical principles, new technologies and new structures, takes unconventional vehicle fuel as the power source (or uses conventional vehicle fuel but adopts new vehicle power devices), and integrates advanced technologies of vehicle power control and driving. New energy vehicles include: hybrid electric vehicle (HEV), pure electric vehicle (BEV), fuel cell vehicle (FCEV), hydrogen engine vehicle, gas vehicle and alcohol ether vehicle. Hybrid power refers to those vehicles that use traditional fuels and are equipped with motors/engines to improve low-speed power output and fuel consumption. According to different fuel types, it can be mainly divided into two types: gasoline hybrid power and diesel hybrid power. In the domestic market, the mainstream of hybrid electric vehicles is gasoline hybrid, while diesel hybrid electric vehicles are developing rapidly in the international market.

Advantages:

1. After adopting hybrid power, the maximum power of internal combustion engine can be determined according to the average required power. At this time, it works under the best working conditions of low fuel consumption and less pollution. When the high power required by the internal combustion engine is insufficient, it is supplemented by the battery; When the load is small, the surplus power can generate electricity to charge the battery. Because the internal combustion engine can work continuously and the battery can be charged continuously, its journey is the same as that of an ordinary car.

2. Because of the battery, it is very convenient to recover energy when braking, downhill and idling.

3. In busy urban areas, the internal combustion engine can be turned off and driven only by batteries to achieve "zero" emissions.

4. With the internal combustion engine, it is convenient to solve the high energy consumption problems such as air conditioning, heating and defrosting encountered by pure electric vehicles.

5, you can use the existing gas station to refuel without investment.

6, can keep the battery in good working condition, without overcharge and overdischarge, prolong its service life and reduce the cost.

Disadvantages: Long-distance and high-speed driving hardly saves fuel. As the name implies, electric vehicles are mainly driven by electricity. Most vehicles are directly driven by motors, some are installed in the engine compartment, and some directly use wheels as the rotors of four motors. The difficulty lies in energy storage technology. It does not emit harmful gases that pollute the atmosphere. Even if it is converted into power plant emissions according to electricity consumption, other pollutants except sulfur and particulate matter are obviously reduced. Because most power plants are built far away from densely populated cities, it does little harm to human beings, and the power plants are fixed, and centralized emission is easy to remove all kinds of harmful emissions, and related technologies have been developed. Because electricity can be obtained from various primary energy sources, such as coal, nuclear energy, water power, wind power, light and heat. People's worries about the exhaustion of oil resources have eased. Electric vehicles can also make full use of the remaining electricity when the electricity consumption is low at night, so that the power generation equipment can be fully utilized day and night, greatly improving its economic benefits. Relevant research shows that the same crude oil is sent to the power plant to generate electricity, and then it is driven by the battery, and its energy utilization efficiency is higher than that of refined gasoline and then driven by gasoline engine, so it is beneficial to energy conservation and emission reduction. It is these advantages that make the research and application of electric vehicles a "hot spot" in the automobile industry. Some experts believe that for electric vehicles, the biggest obstacle at present is that infrastructure construction and price affect the industrialization process. Compared with hybrid power, electric vehicles need infrastructure more than one enterprise can solve. Only when enterprises unite with local government departments can they have opportunities for large-scale promotion.

Advantages: the technology is relatively simple and mature, and it can be charged wherever there is electricity.

Disadvantages: The battery with unit weight stores too little energy, and the battery of electric vehicle is expensive, which does not form an economic scale, so the purchase price is expensive. As for the use cost, some trial results are more expensive than cars, and some results are only 1/3 of cars, mainly depending on the battery life and local oil and electricity prices. Fuel cell vehicles refer to vehicles that use hydrogen, methanol and other fuels. As fuel, it generates current through chemical reaction and is driven by motor. The energy of its battery is directly converted into electric energy through the chemical action of hydrogen and oxygen, not through combustion. The chemical reaction process of fuel cells will not produce harmful products, so fuel cell vehicles are pollution-free vehicles, and the energy conversion efficiency of fuel cells is 2~3 times higher than that of internal combustion engines. Therefore, from the aspects of energy utilization and environmental protection, the fuel cell vehicle is an ideal vehicle.

Single fuel cells must be combined into fuel cells in order to obtain the necessary power and meet the requirements of vehicle use.

In recent years, fuel cell technology has made great progress. World famous automobile manufacturers, such as DaimlerChrysler, Ford, Toyota and General Motors, have announced that they plan to put fuel cell vehicles on the market before 2004. Prototypes of fuel cell vehicles are being tested, and fuel cell-driven transport buses are undergoing demonstration projects in several cities in North America. There are still technical challenges in the development of fuel cell vehicles, such as the integration of fuel cells, the improvement of fuel processors and auxiliary components of commercial electric vehicles. Automobile manufacturers are working hard to integrate parts and reduce the cost of parts, and have made remarkable progress.

Compared with traditional cars, fuel cell cars have the following advantages:

1, zero emission or near zero emission.

2. The water pollution caused by oil leakage is reduced.

3. Reduced greenhouse gas emissions.

4. Improved fuel economy.

5. The combustion efficiency of the engine is improved.

6, smooth operation, no noise. Hydrogen-powered vehicles are truly zero-emission vehicles, which emit pure water, no pollution, zero emission and abundant reserves. Therefore, hydrogen-powered cars are the most ideal substitutes for traditional cars. Compared with traditional power vehicles, the cost of hydrogen-powered vehicles is at least 20% higher. China Changan Automobile completed the ignition of the first high-efficiency zero-emission hydrogen internal combustion engine in China in 2007, and exhibited China's first hydrogen-powered concept sports car "Hydrogen Range" at the 2008 Beijing Auto Show.

With the gradual formation of "automobile society", the number of cars is rising, but resources such as oil are stretched. On the other hand, vehicles that consume a lot of gasoline constantly emit harmful gases and pollutants. The ultimate solution, of course, is not to limit the development of the automobile industry, but to open up a new energy source instead of oil. The four wheels of a fuel cell car roll across the road quickly and quietly, marking the name of a new energy source-hydrogen.

Almost all the world automobile giants are developing new energy vehicles. Electricity was once considered as the future power of automobiles, but people gradually lost interest in it because of the long charging time and weight of batteries. In 2009, the hybrid vehicle of electric power and gasoline can only temporarily alleviate the energy crisis, and can only reduce but can't get rid of the dependence on oil. At this time, the emergence of hydrogen-powered fuel cells is like rebuilding a Noah's Ark, which makes people see infinite hope from the crisis.

The idea of using hydrogen as automobile fuel was shocking when it first came out, but it was actually well-founded. Hydrogen has a high energy density and can release enough energy to run an automobile engine. Moreover, the chemical reaction between hydrogen and oxygen in the fuel cell only produces water, without pollution. Therefore, many scientists predict that the fuel cell powered by hydrogen will be the core technology of the 2 1 century automobile, and its revolutionary significance to the automobile industry is equivalent to that of the microprocessor to the computer industry.

Advantages: the emission is pure water, and no pollutants are generated when driving.

Disadvantages: the cost of hydrogen fuel cells is too high, and the technical conditions for storage and transportation of hydrogen fuel are very difficult, because hydrogen molecules are very small and easily escape through the shell of the storage device. In addition, the most fatal problem is that extracting hydrogen requires electrolysis of water or the use of natural gas, which also consumes a lot of energy. Unless nuclear power extraction is used, carbon dioxide emissions cannot be fundamentally reduced. Gas-fired vehicles refer to vehicles fueled by compressed natural gas (CNG), liquefied petroleum gas (LPG) and liquefied natural gas (LNG). Governments all over the world are actively seeking to solve this problem and begin to adjust the fuel structure of automobiles. Gas vehicle is recognized as the most ideal alternative fuel vehicle in the world because of its good emission performance, adjustable fuel structure, low operating cost, mature technology, safety and reliability.

Gas is still the mainstream of alternative fuels in the world, accounting for about 90% of alternative fuel vehicles in China. The goal of the United States is that by 20 10, 7% of cars in the field of public transport will use natural gas, and 50% of taxis and buses will be changed to cars dedicated to natural gas; By 20 10, the number of natural gas vehicles in Germany will reach 654.38+million to 400,000, and the number of filling stations will increase from 180 to 300.

Experts in the industry pointed out that the role of alternative fuels is to alleviate and eventually eliminate all kinds of pressures brought about by tight oil supply and the negative impact on economic development. China will still mainly use compressed natural gas, liquefied gas and ethanol gasoline as alternative fuels for automobiles. Whether the application of alternative fuels for automobiles can be expanded depends on the resources, distribution and availability of alternative fuels in China, the maturity of production and application technology of alternative fuels, and the reduction of environmental pollution. The production scale, investment, production cost and price of alternative fuels determine their competitiveness with petroleum fuels; The improvement of automobile production structure and design must be compatible with fuel.

Replacing oil with gas will be the inevitable trend of automobile development in China and even the world. China should organize forces to formulate the national gas vehicle policy as soon as possible. Considering that China's energy security is mainly oil, it is urgent to develop various alternative fuel vehicles, including gas vehicles. According to the national conditions, we should do the following:

First, it is necessary to limit gas prices, maintain a reasonable oil-gas price difference, such as Sichuan-Chongqing oil-gas price difference, and ensure the moderate development of gas vehicles;

Second, in view of the characteristics of large investment and long payback period of filling stations, the government appropriately gives certain subsidies to adjust the benefit distribution between the gas price sold by filling stations and the fuel cost saved by automobile users due to gas use;

Third, the gas station income tax is exempted from two and reduced by three according to the policy of high-tech industrial development zone;

Fourth, the TV used in the gas filling station is special industrial electricity, and the electricity price is preferential; In addition, the filling station land can be used as a major project and an environmental protection industry, and it can be handled in a special way, without passing the buck, actively adopting advanced foreign standards for station construction, scientifically determining the fire safety distance and saving land resources. Ethanol is commonly known as alcohol. Generally speaking, cars that use ethanol as fuel can also be called alcohol cars. The activity of replacing petroleum fuel with ethanol has a long history, and the technology is mature in production and application. Due to the shortage of oil resources and the increasing diversification of automobile energy, ethanol vehicles are once again put on the agenda.

More than 40 countries in the world have used ethanol vehicles to varying degrees, and some have reached large-scale promotion, and the status of ethanol vehicles is improving day by day.

Using ethanol in automobile can improve the octane number of fuel, increase the oxygen content, make the combustion in automobile cylinder more complete, and reduce the emission of harmful substances in exhaust gas.

Fuel application mode of ethanol vehicle;

1. Mixed combustion refers to the mixed application of ethanol and gasoline. In mixed fuel, the ratio of ethanol to volume is represented by "E". If ethanol accounts for 10% and 15%, E 10 and E 15 are the representatives, and blended combustion accounts for the main position of ethanol vehicles.

Second, pure combustion, that is, ethanol single combustion, can be expressed by E 100%, which is not widely used and belongs to the trial stage;

3. Denatured fuel ethanol refers to ethanol generated by adding denaturant after ethanol dehydration, which also belongs to experimental application steps;

4. Flexible fuel means that the fuel can be gasoline, ethanol or a mixture of methanol and gasoline, and hydrogen can also be used, and can be switched at any time. For example, both Ford and Toyota are experimenting with flexible fuel vehicles. develop

As an important oil refining product, diesel occupies a high share in the fuel structure of various countries and becomes an important power fuel. With the acceleration of the world automotive diesel trend, the demand for diesel will increase in the future. The exhaustion of petroleum resources and the improvement of people's awareness of environmental protection have greatly promoted the development of diesel alternative fuels in all countries of the world, especially in the 1990s. Biodiesel has attracted the attention of all countries because of its superior environmental protection performance. biodiesel

Biodiesel refers to a renewable diesel fuel that can replace petrochemical diesel oil by transesterification with aquatic vegetable oil such as oil crops, wild oil plants and engineering microalgae, as well as animal oil and kitchen waste oil. Biodiesel is a kind of biomass energy, which is a long-chain fatty acid monoalkyl ester obtained by biomass pyrolysis and other technologies. Biodiesel is a mixture of complex organic components with extremely high oxygen content. These mixtures are mainly some high molecular weight organic compounds, including almost all kinds of oxygen-containing organic compounds, such as ethers, esters, aldehydes, ketones, phenols, organic acids, alcohols and so on.

key property

In order to provide clean oil products to the market and make the tail gas emission from burning diesel meet the standard requirements, oil refining enterprises need to take the following three measures: first, they need to have excellent deep hydrodesulfurization catalysts to remove aromatic sulfur compounds such as 4,6-dimethylbenzothiophene, which are difficult to hydrodesulfurize; Secondly, it is necessary to have sulfur-resistant noble metal aromatics saturation catalyst, which can saturate aromatics under lower pressure to save investment; Third, there must be a process to improve the cetane number. With its excellent environmental protection performance, biodiesel can easily meet the requirements of diesel II and III standards in the world fuel specification.

As we all know, diesel oil molecules are composed of about 15 carbon chains. It is found that vegetable oil molecules are generally composed of 14 ~ 18 carbon chains, which is similar to the number of carbon chains of diesel oil molecules. Therefore, biodiesel is a new fuel made from renewable vegetable oil such as oil color seeds. According to the chemical composition analysis, biodiesel fuel is a kind of methane with high fatty acid, which is obtained by decomposing glyceride with unsaturated oleic acid C 18 as the main component [1]. Compared with traditional diesel, biodiesel has the following incomparable properties.

(1) has excellent environmental protection characteristics. Mainly because the sulfur content in biodiesel is low, and the emission of sulfur dioxide and sulfide is low, which can be reduced by about 30% (70% when there is catalyst); Biodiesel does not contain aromatic alkanes that will pollute the environment, so the harm of tail gas to human body is lower than that of diesel. The test shows that compared with ordinary diesel, the use of biodiesel can reduce the air toxicity by 90% and the blockage rate by 94%. Due to the high oxygen content of biodiesel, the smoke emitted during combustion is less, and the carbon monoxide emission is reduced by about 10% compared with diesel (95% when there is a catalyst); Biodiesel has high biodegradability.

(2) It has good low-temperature engine starting performance. The cold filtration point without additives reaches -20℃.

(3) It has good lubrication performance. Fuel injection pump, engine cylinder block and connecting rod have low wear rate and long service life.

(4) It has good safety performance. Biodiesel is not dangerous because of its high flash point. Therefore, it has obvious advantages in transportation, storage and use.

(5) It has good fuel performance. High cetane number makes it burn better than diesel oil, and slightly acidic combustion residue prolongs the service life of catalyst and engine oil.

(6) renewable. As a renewable energy, unlike oil reserves, its supply will not be exhausted through the efforts of agricultural and biological scientists.

The excellent performance of biodiesel makes the engine exhaust emission index using biodiesel not only meet the Euro II standard, but even meet the stricter Euro III emission standard to be promulgated and implemented in Europe. Moreover, because the carbon dioxide emitted by biodiesel combustion is far lower than the carbon dioxide absorbed during plant growth, the global warming caused by carbon dioxide emission has been improved, which is a major environmental problem that harms human beings. Therefore, biodiesel is a real green diesel.

development trends

Modern diesel engines have accelerated the trend of dieselization of automobile models.

In Europe, the proportion of new diesel vehicles purchased by 1999 is about 30%, and France even reaches 48%. In 2000, the sales volume of diesel vehicles in the European market reached 4.4 million, twice that of 1995. In 30 13, almost half of the customers of the major manufacturers of economical cars such as Volkswagen, Renault, Opel and Ford need diesel vehicles. In 20 13, the purchase rate of new diesel vehicles in European automobile market reached 30%. Experts predict that by 2006, there will be 1 new cars in Europe that are diesel vehicles. In the American market, 90% of commercial vehicles (that is, trucks and buses in China) are diesel vehicles; In Japan, nearly 10% of cars are diesel vehicles, and 38% of commercial vehicles are diesel vehicles. Heavy trucks in America, Japan and Europe all use diesel engines as power. Many countries give preferential policies in taxation and fuel supply to promote the popularization and development of diesel engines. The production proportion of diesel vehicles in China has increased from 15% in 1990 to 26% in 1998. During the period of 1997, all heavy trucks and buses produced in China used diesel engines; 65.9% medium-sized trucks use diesel engines, and 53.5% medium-sized buses use diesel engines; 55.4% and 29.4% of light trucks and light buses also started to use diesel engines. China's 1994 Industrial Policy for Automobile Industry clearly states that after 2000, passenger cars with a total weight of more than 5 t will mainly use diesel as fuel. In the next few years, China's automobile industry will take off. Therefore, the increasing trend of diesel vehicle output in China will continue, and diesel vehicle is a development direction of China automobile industry.

The acceleration of the diesel trend of automobile models is mainly due to the adoption of electronic control engine control system, high-pressure fuel direct injection combustion system and exhaust emission control device in modern diesel engines, which completely overcomes the shortcomings of traditional diesel engines and can meet the current international emission standards. These devices and technologies require diesel oil to have low sulfur content, good stability and lubricity, high cetane number and cleanliness. With the maturity of modern diesel engine using biodiesel fuel technology, the world diesel trend of this model will be further accelerated in 20 13 years. According to experts' prediction, before 20 10, the demand for diesel will increase by 3.3% every year, and by 20 10, the global demand for diesel will increase from the current 38% in 20 13 to 45%. However, the global diesel supply is seriously insufficient, leaving a broad development space for biodiesel. Many years ago, scientists predicted that one day in the world, cars could be driven by water. Today, although this step has not been realized, the technology of using hydrogen in water as power source has become a reality. Toyota Company of Japan has successfully developed a new generation of electric vehicles, named FCEV, which generates electricity through the chemical reaction of hydrogen and oxygen.

FCEV, the abbreviation of Fuel Eiectric Vehicle in English, should be methanol fuel cell electric vehicle in Chinese. As the name implies, the main fuel of FCEV is methanol (commonly known as alcohol). In the car, the cylinder is still kept, but instead of gasoline, methanol is injected. A methanol regulator consisting of an evaporation part, a regulation part and a carbon monoxide reduction part is installed in the engine room. When the fuel pump sends the mixed liquid of methanol (CH3OH) and water (HO2) from the oil cylinder to the regulator, it will turn into steam when heated in the evaporation part, and then into hydrogen (H2) and carbon dioxide under the action of the catalyst in the regulator part. Trace harmful carbon monoxide (CO) gas will be reduced by reducing the CO part. Finally, only hydrogen and carbon dioxide will be sent to the hydrogen electrode of the fuel cell, which will be converted into electric energy through chemical reaction. In this way, methanol can continuously pass through the regulator and become electric energy, thus driving the car.

Needless to say, the advantage of this methanol powered car is to achieve environmental protection. Repeated tests show that its morale and carbon dioxide emissions are less than half of those of alternative cars. As for the emissions of carbon monoxide, hydrocarbons, nitrogen oxides and other harmful substances, although it is not zero, it has reached a very low index. Moreover, the cost of methanol is much lower than that of gasoline, and it can travel continuously for 400-500 kilometers once filled. Moreover, the most rare thing is that FCEV does not need to rebuild the oil tank to accommodate it, but only needs to replace the existing oil tank with methanol, which is simple and economical and has great development potential.