1 The development background of electronically controlled engines
In the 1940s, Germany's Daimler-Benz and Bayer engine manufacturers first equipped automobile engines with fuel injection systems. However, due to various This reason is only the use of mechanical fuel injection systems on German aircraft.
In the 1950s, the German Daimler-Benz company equipped its Mercedes-Benz 300l car with a mechanical fuel in-cylinder injection system.
In 1953, the American Bendix Company began to develop an electronically controlled fuel injection system. In 1957, the Bendix Company's electronically controlled fuel injection system came out and was equipped in Kelai. On the Siler sedan.
In the 1960s, due to the very active development of electronic technology and the country's restrictions on vehicle exhaust gas emission concentration, there was a world energy crisis. Automobile manufacturers in various countries made various improvements to carburetors, but still could not meet the requirements. Increasingly tight restrictions.
In 1967, the German Bosch company developed a jetronic electronically controlled fuel injection system for the first time and applied it to the Vuxwagen VW-1600 car. It was exported to the United States in large quantities and was the first to reach the exhaust emission level of some countries. Emission concentration limits.
In 1973, the German Bosch company launched the l-jetronic electronically controlled fuel injection system.
Mass flow control lh-jetronic type electronically controlled fuel injection system.
In 1979, the German company Bosch produced a motronic digital engine integrated control system that integrated electronic ignition and electronically controlled fuel injection.
In 1980, the American GM (General Motors) company Ford (Ford) first launched the SPI single-point injection electronically controlled fuel injection system.
The development of new technologies has a tendency to replace traditional carburetors.
In the 1980s, electronically controlled fuel injection systems were widely used in automobiles.
According to statistics, the proportion of electronically controlled fuel injection systems adopted in 1993 was: 100 in the United States, 80 in Japan, and 98 in Germany.
Electronically controlled fuel injection system technology is used not only in cars, but also in various types of vehicles, fully demonstrating its strong vitality.
Electronic fuel injection replaces the traditional carburetor, which greatly improves the power performance of the generator and increases the maximum output power of the generator; high air-fuel control accuracy is the biggest advantage of electronic fuel injection, regardless of the environment When conditions such as temperature = atmospheric pressure change, or during unsteady working conditions such as acceleration, deceleration, and transition, as well as hot and cold conditions such as starting, warming up, high-temperature operation, and restarting, the generator can obtain an air-fuel ratio that accurately meets the requirements, thus comprehensively Greatly improved performance.
Under stable operating conditions, electronically controlled injection uses oxygen sensor feedback to control the air-fuel ratio, and *** the role of the three-catalyst reactor can achieve the best exhaust purification effect.
In other working conditions, due to precise control of the air-fuel ratio, fuel can be supplied on demand, thus reducing fuel consumption.
The emergence of EFI technology is the result of the development of microcomputer control technology.
In the future, with the advancement of microcomputer functions and control technology, generator control will develop in the direction of comprehensive centralized control, and the electronically controlled gasoline injection device will be used as an important part of the centralized control system to cooperate with it. develop.
At the same time, with the advancement of control theory and technology, the application and practicalization of new control principles in electronic control technology will also become an important development direction and research topic.
Electronic injection engines are the development direction of my country’s vehicle engines in the 21st century.
In accordance with the "Tenth Five-Year Plan" for automotive electronic equipment products, my country will accelerate the development of the three major electronic equipment of automotive electronic fuel injection systems, ABS and airbags during the "Tenth Five-Year Plan" period.
The efi system is a key assembly and system component of automotive products that has been intensively developed and supported in our country.
At present, domestic efi system products include single-point injection type and multi-point injection type. The control methods include individual control and centralized control, which have great development potential.
However, the localization process of key components is slow, key components and processes need to be localized, and central processing units are in the process of being overproduced.
my country's goal is to reach the level of foreign countries in the 1990s after the "Tenth Five-Year Plan" technical reform.
2 Overview of the development of electronically controlled engines
Early gasoline injection systems adopted mechanical control methods and were applied in aircraft engines.
After the end of World War II, gasoline injection technology was applied to automobile engines. However, due to high cost and technical difficulty, it was only used in some high-end cars and racing cars.
In the 1960s, due to the rapid development of electronic technology and the impact of automobile emission regulations, gasoline injection technology was promoted to general automobiles.
In the 1970s, the energy crisis and the development of electronic technology made electronically controlled gasoline injection an important development direction of the automobile industry. With the development of electronic technology, electronically controlled gasoline injection systems have experienced changes from transistors to integrated circuits. to microcomputer control, and the development process from analog to digital.
In 1967, the German Bosch company Bendix took the lead in developing a d-jetronic gasoline injection system based on the patent. It was mass-produced for the first time in the 1970s and was the first to meet the requirements of the California automobile emission regulations at that time. Created the application history of gasoline injection electronic control system.
In order to improve the poor control effect of the d-jetronic system when the working conditions change, Bosch has developed the l-jetronic electronically controlled fuel injection system with mass flow control.
Later, the l-jetronic system further developed into the lh-jetronic system.
The lh-jetronic system can accurately measure air flow and compensate for the effects of atmospheric pressure and temperature changes. It further reduces the air intake resistance, has faster response speed, and has superior performance.
The development of large-scale integrated circuits and microcomputers has created favorable conditions for the birth of comprehensive control systems for automobile engines to achieve the best comprehensive performance indicators.
In 1979, Bosch began to produce the motronic digital engine integrated control system integrating electronic ignition and electronic fuel injection. This control system can control air-fuel ratio, ignition time, idle speed and exhaust gas recirculation, etc. comprehensive control.
Subsequently, the world's major automobile manufacturers have successively launched their own products, including GM's EFI system and TBI system, Ford's EEC system, Chrysler's CFI system, Nissan ECCS system, and Toyota TCCS system. , Mitsubishi ect-jet system and Lucas's ems system. At the same time, sensors and automotive-specific control chips have developed rapidly.
Before the 1980s, gasoline engine injection mostly used a multi-point gasoline injection system. In 1980, gm company first successfully developed a simple structure and low-cost TBI system. This system uses low-pressure injection and uses lower The injection pressure and fewer injectors were able to meet the regulatory requirements at the time, and they were rapidly popularized and developed.
In 1983, Bosch also launched the mono-jetronic single-point gasoline injection system.
In the late 1980s and early 1990s, due to the further improvement of engine performance and structural requirements and the further tightening of regulatory requirements, the multi-point gasoline injection system regained its advantages and once again took the dominant position.
With the application of microprocessors in automobiles, the primary task of automobile engine electronic control systems is to determine the best characteristics of the engine system based on various performance indicators, which can correspond to various working conditions, environments and The state automatically adjusts and compensates accordingly to keep the engine running at optimal conditions.
At present, the content of electronic control mainly includes: fuel injection control, ignition and knock control, in addition to idle speed control, overspeed protection, deceleration fuel cutoff, exhaust gas recirculation control, boost control, variable gas Valve timing control, engine fault self-diagnosis and fail-safe systems, etc.
3 Development Trends of Electronically Controlled Engines
With the continuous tightening of emission regulations and the rapid development of electronic technology, gasoline engine electronic control technology has made significant progress. As a new technology A solid foundation has been established in the automotive industry.
At present, the development trend of electronic control of gasoline engines is still very strong.
The research and development of gasoline engine electronic control systems is mainly reflected in several aspects:
3.1 Controller With the rapid development of electronic technology, the engine controller is miniaturized and has multiple functions. Getting stronger and stronger.
At present, the hardware of electronic control units is constantly enriched, the degree of integration is getting higher and higher, the data collection, calculation and communication speed are constantly improving, and transient changes in combustion pressure can also be processed in real time.
Engine control is developing in the direction of comprehensive control, which not only controls the engine itself but also integrates vehicle automatic transmission, active suspension and vehicle speed control into an integrated vehicle management system.
Currently, 16-bit computers have replaced 8-bit computers as the mainstream model of automotive microcomputers, and are moving towards 32-bit computers, which will strongly support the development of more and more advanced functions in the control system.
3.2 Sensors The development trend of sensors is towards miniaturization, integration and intelligence. They can automatically compensate for temperature and voltage, and automatically recover from performance degradation caused by long-term use; they have self-diagnosis and self-repair. function, and directly outputs digital signals, simplifying the control unit; the sensor itself has strong anti-interference ability, enhancing the reliability of the system.
At present, the development of new sensors is mainly focused on the two fields of combustion data sensor development and engine output parameter detection.
3.3 The development of control software is highlighted by the practical application of new control theories in engine control. The control theory of gasoline engines has moved from open-loop control to closed-loop control, and from optimal control to adaptive and self-learning control. Eventually moving towards neural network intelligent control.
In the next period of time, the development of control software will mainly be reflected in several aspects:
①Develop control algorithms for new variables;
②Develop control algorithms for Conduct simulation research;
③ Conduct simulation application research for the expert system for off-vehicle diagnosis and the control system used in the car.
The development of a new generation of electronically controlled engines includes:
a) Research on lean combustion technology of gasoline engines;
b) Research on in-cylinder direct injection technology of gasoline engines.
In short, electronic control plays a central role in the current development of engine control.
In the future, engine electronic control will develop in the direction of high precision and compactness with the various requirements of society and the development of various new technologies and new materials.
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