Research on Gasoline Direct Injection Engine

A revolution in the “heart” of automobiles??? Current status of research and development of gasoline direct-injection engines

Faced with increasingly stringent automobile exhaust emission regulations, is it time for the traditional gasoline engine to withdraw from the stage of history? The emergence of gasoline direct injection technology has brought the development of gasoline engines into a new era and is expected to replace traditional gasoline engines And diesel engines have become the ideal power for future automobiles.

1. The superior performance of gasoline direct-injection engine is referred to as GDI, which is a hot spot in the research and development of foreign internal combustion engine technology in recent years. The traditional gasoline engine injects gasoline into the intake pipe, mixes with air and then enters the cylinder for combustion, while the GDI engine injects gasoline directly into the cylinder, using the airflow in the cylinder and the fuel atomization on the piston surface to form a mixture with air Carry out combustion. Compared with conventional gasoline engines, GDI has good working stability. At the same time, low-temperature starting has been significantly improved, stratified combustion can be realized, fuel economy is greatly improved, and its fuel consumption can reach that of turbocharged direct injection (TDI) diesel engines. Level, and omits the turbocharger, eliminating the complicated high-pressure injection system. The GDI engine can use lean-burn technology, and the air-fuel ratio can reach 40 or even 100:1, making the power and torque higher than traditional gasoline engines, and the fuel consumption, noise and carbon dioxide emissions are lower. The uniformity, instantaneous reactivity and startability of the GDI engine are greatly improved compared to the traditional gasoline engine. With the continuous maturity and improvement of gasoline direct injection technology, other superior performance will be further demonstrated, and there is still great potential for development. . Therefore, all countries are vigorously developing this GDI engine with advanced technology and excellent performance.

Second, the development process of gasoline direct injection engine Gasoline direct injection engine can be described as a flower blooming in Germany, but the fruit is ripe in Japan. As early as the 1950s, direct-injection two-stroke gasoline engines appeared in Germany, and they were even installed on the famous SL-Class Mercedes-Benz cars. However, due to the poor running performance of this engine at that time, the car could hardly be driven and the exhaust gas problem was more serious. Very quickly disappeared. Later, Japan’s Mitsubishi Corporation successfully developed a GDI engine in 1996, installed it and put it on the Japanese car market in August of the same year. In 1997, Zhongzhong equipped with the same engine entered the Western European market. The engine has a displacement of 1.8L, a power of 88kW, and a fuel consumption of about 5L per 100 kilometers. Mitsubishi plans to convert all its gasoline engines to gasoline direct injection in the past few years. The success of Mitsubishi Corporation shows that direct gasoline injection is feasible, and the problem of high NO in exhaust gas can be solved by exhaust gas recirculation and the installation of catalytic cracking conversion devices.

Compared with traditional indirect-injection gasoline engines, GDI has made great progress in terms of fuel consumption and exhaust purification, and in terms of lean combustion, GDI engines allow the mixture to become leaner, especially in partial load conditions. The theoretically calculated standard air-fuel ratio should be 15:1. Toyota and Mitsubishi have achieved preliminary results in lean combustion technology. The air-fuel ratio has reached 20:1, but if direct gasoline injection is used, the mixture can be further lean. . Usually the intake ducts are arranged more or less horizontally, while the Mitsubishi GDI engine successfully establishes a stratified charge in the combustion chamber through the vertically arranged intake ducts and specially designed nose-shaped pistons. In the area, a thicker oil mist is formed, that is, a mixture that can catch fire. In other areas, there is no mixture at all. Therefore, even if the air-fuel ratio is 40:1, the engine can reliably catch fire. When the throttle is maximum, the mixture is close to the standard air-fuel ratio. At this time, the advantage of fuel saving disappears, but the car rarely works under full load conditions. .

The successful development of Mitsubishi’s GDI engine has set off a worldwide research and development boom. Since then, the development of gasoline engines has taken a new step and will promote the development of the world’s automobile industry.

Third, the development status of gasoline direct injection engines The development and utilization of GDI engines, Japan’s Mitsubishi Corporation is currently in the world’s leading position. When automakers began to invest heavily in research on fuel cells and other alternative fuels for automobiles, Mitsubishi was confident in further developing gasoline direct injection technology. Although Japanese automakers also began to study fuel cell technology, Mitsubishi firmly believed that it was demonstrated in 1996. The gasoline direct injection technology of China is a long-term effective technology rather than a temporary technology. The senior official of Mitsubishi Corporation in charge of product research and development said: Fuel cells have their place and we are using them in suitable vehicles. This ultra-reliable and ultra-clean gasoline direct injection technology will be promising in the future. .

In 1997, Mitsubishi Corporation successively developed three models of 2.4L four-cylinder engine, 3.0L six-cylinder engine and 3.5L six-cylinder engine, which were installed on four medium and large cars respectively. In 2000, three new GDI engines were introduced: 0.66L inline three-cylinder engine, 1.5L inline four-cylinder engine and 4.5L V8 engine. According to Mitsubishi’s test of 1.8LGDI engine, compared with conventional gasoline engines, this model can save 20% fuel, reduce emissions by 20%, increase engine power, and at the Frankfurt Motor Show in September 1999, the company’s four Two of the concept cars made their debut on stage. Although the details of the show are still in the confidential stage, Mitsubishi hopes that these two concept cars will become models of urban vehicles. One of them represents the latest achievement of Mitsubishi’s GDI? Sigma series of power technology, showing this epoch-making automobile internal combustion engine technology. The company *recently announced in Japan that the GDI? Sigma direct injection combustion engine has a series of relevant new technologies, such as: continuous variable transmission technology, idling hybrid power, low-consumption turbocharging technology, the result of which is the economy of the car Compared with the current GDI launch, according to the results released by Mitsubishi, due to the existence of conventional engines and automatic transmissions, automobiles have been plagued by problems such as drive belt friction loss, torque conversion power loss, automobile vibration, and low fuel efficiency. GDI? Sigma The integrated control and transmission of the gasoline engine makes these problems solved. GDI engines can provide greater torque output and more reliable combustion methods. They use different hydraulic pressures to match engine power, which can reduce fuel waste caused by belt slippage caused by high torque when pressure changes. Tests used in urban areas have shown that the idling consumption of a multi-port gasoline injection engine accounts for 16% of fuel energy, while this loss can be reduced to 10% in a GDI engine, and energy consumption can be reduced from a standstill to a restart of the vehicle. In addition, the system also has the characteristics of fast starting. A hybrid car equipped with GDI developed by Mitsubishi, by providing a simple hybrid system (a car engine and battery), GDI can start and accelerate within 0.1s. Mitsubishi’s two-stage hybrid patent can produce a higher compression ratio, and the ultra-lean combustion of the turbo engine can provide higher power.

Toyota also successfully developed the D-4 2.0LGDI engine at the end of 1996, and it has been put into use in batches. In 1998, the company developed 1.6L and 1.8L GDI engines, followed by a new 2.0L GDI engine in 1999. According to Toyota’s test of the D-4 GDI engine, the engine can reduce fuel consumption by 30% and increase power by 10%. The 3.0L and 2.5L V6 engines developed by Nissan, the 2.5L horizontal four-cylinder engine and Fuji Heavy Industries’ 2.5L horizontal four-cylinder engine Honda’s 1.0L inline three-cylinder engine will also be on the market after 2000.

The four-stroke GDI engine developed by Chrysler Automobiles has improved fuel economy by 20% to 30%, which is comparable to small-displacement direct-injection diesel engines; Ford has conducted in-depth research on GDI engines and found that GDI engines have further improved thermal efficiency And power potential.

After the GDI engine developed by Volkswagen was well received at the 1997 Frankfurt Motor Show, Audi also exhibited a 1.2L three-cylinder GDI engine. As early as the end of 1997, Mercedes-Benz invested 100 million marks to fully carry out GDI research projects. The company plans to launch GDI engines in 2001 or 2002, and believes that European-equipped GDI engines can meet the latest requirements of European regulations for emission standards.

At present, gasoline direct injection engines have attracted the attention of major automobile manufacturing companies in the world, and they have joined the ranks of research and development. With the advent of the 21st century, GDI engines will show their prowess in automotive power plants. For automotive parts and parts machining , PTJ Shop offers the highest degree of OEM service with a basis of 10+ years experience serving the automotive industry. Our automotive precision shop and experts deliver confidence. We have perfected the art of producing large component volumes with complete JIT reliability, backed by the quality and long-term reliability our customers expect.

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