Automobiles were originally a technology that was mainly biased towards mechanical cooperation. In recent decades, with the rapid development of electronic technology, all walks of life have begun to promote mechatronics. Cars are no exception. If today's car mechanics stay in the previous pure experience-accumulated car repair, it can only prove that he has been in the car industry for a long time. Today's cars are driven by hundreds of electronic components, and the number of bundled car lines controls the coordination of multiple departments of the car. Automotive electronics technology has fully covered the automotive industry. Today's advanced technologies are linked to electronic technology: EFI engines, electric windows, power seats, electronically controlled body stabilization systems, electronic displays, electronically controlled suspensions, and more. Today's cars are equipped with a computer-ECU to regulate the operation of the entire car, and automotive electronics has become the biggest source of automotive technology. Foreign experts predict that the cost of electronic devices for automotive interiors will account for more than 25% of the cost of complete vehicles in the next 3-5 years. Automobiles will develop from simple mechanical products to advanced mechatronic products, becoming so-called "electronic cars."
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Of course, the car is not related to the circuit hobby. It comes down to the fact that the early car circuit was mainly the conversion of energy. Today's electronic technology mainly lies in the overall control of the car.
Ignition system
Recall that the earliest circuit on the car is not the ignition system of the gasoline engine. In order to ignite the gasoline in the cylinder, it is necessary to generate sparks constantly. Therefore, scientists at that time used the principle of electromagnetic induction to make a small transformer in the automobile to make the spark plug instantaneously generate a very high voltage and ignite. This technology is still common in modern cars!
Starting system
Another early car- and circuit-related non-starter was the first to use a hand-cranked starter (like some tractors today), but hand-cranked is inconvenient for women. Then the invention of the starter was reinstated. It is reported that the invention of the starter was due to an accident. When an English gentleman helped a half-way stalled Cadillac girl start the car, the starter bar counterattack led to the death of the gentleman, and the gentleman was a good friend of the general manager at the time, so a technical battle was started under the command of the boss. The working form of the starter's conversion of electrical energy into mechanical energy that propels the flywheel is also established. Today's starter is still the way of working, but the workmanship and durability are more perfect.
For a long time, the electronic technology on the car was limited to the work driven by the motor. It can be said that for a long time, the car was just a "pure" mechanical monster with several circuits. But with the breakthrough of scientists in electronic technology, automotive electronics technology has also ushered in the spring.
Automotive electronics technology on the engine:
1. Electronically controlled fuel injection unit (EFI)
In modern vehicles, mechanical or electromechanical hybrid fuel injection systems have tended to be eliminated, and electronically controlled fuel injection devices have become increasingly popular due to their superior performance. The electronic fuel injection device automatically ensures that the engine is always operating at its optimum condition, so that it can maximize fuel economy and purify air at a certain power output. After experimenting and correcting the oil supply control law when the engine is in the best working condition, the objective laws are programmed into the memory of the microcomputer in advance. When the engine is working, the air flow measured by each sensor and the exhaust pipe are included. Parameters such as oxygen volume, intake air temperature, engine speed and operating temperature are calculated according to pre-programmed operating procedures, and then compared with the parameters of the best operating conditions in the memory to determine the fuel supply. This allows the engine to operate under optimal operating conditions, resulting in improved overall engine performance.
2. Electronic ignition device (ESA)
It consists of a microcomputer, a sensor, its interface, and an actuator. The device can calculate and judge various parameters of the engine sent by the sensor, and then adjust the ignition timing, which can save fuel and reduce air pollution. In addition, the new engine electronic control unit also has adaptive control, intelligent control and self-diagnosis operations. It is generally believed that the energy-saving effect of the engine electronic control device is above 15%, and the more obvious effect is in environmental protection.
In addition, the use of electronic technology in the engine part includes: exhaust gas recirculation (EGR), idle speed control (ISC), electric oil pump, generator output, cooling fan, engine displacement, throttle timing, secondary Air injection, engine boost, oil vapor evaporation and system self-diagnosis functions are used more or less on different models.
3, intelligent variable valve timing technology (VVT-I)
In order to achieve the best air ratio of the engine, the engine can get different fuel supply at different speeds. Toyota's intelligent variable valve timing technology is quite representative.
The VVT-i system consists of sensors, ECUs, and camshaft hydraulic control valves and controllers. The ECU stores the optimal valve timing parameter values, and feedback information such as the crank position sensor, the intake manifold air pressure sensor, the throttle position sensor, the water temperature sensor, and the camshaft position sensor are collected into the ECU and compared with predetermined parameter values. Calculate the correction parameters and issue commands to the control camshaft timing hydraulic control valve. The control valve controls the position of the oil sump valve according to the ECU command, that is, changes the hydraulic flow, and sends the signal command selections such as advance, lag, and hold unchanged to the VVT. -i controller on different oil passages.
Application of electronic technology on the chassis:
1. Electronically controlled automatic transmission (ECT)
ECT can automatically change the position of the shift lever after computer calculation and judgment according to the engine load, speed, vehicle speed, brake working state and various parameters controlled by the driver, thus achieving optimal control of the transmission shift, ie Get the best gear and the best shift time. Its advantages are high acceleration performance, high sensitivity, and accurate reflection of driving load and road conditions. The electronic control unit of the transmission system can automatically adapt to changes in transient conditions and keep the engine running at the lowest possible speed. The electropneumatic shifting device uses an electronic device to replace the mechanical shift lever and its connection with the shifting mechanism, and is executed by a solenoid valve and a pneumatic servo valve cylinder. Not only does it significantly simplify vehicle handling, but it also achieves optimum driving dynamics and safety.
2. Anti-lock brake system (ABS)
The system is an important security component with the longest development time and the fastest application. It controls the car to prevent the wheel from locking up to ensure the best slip rate (15-20%) between the wheel and the ground, so that when the car is braked on various roads, the wheel and the ground can reach the vertical peak. The adhesion coefficient and the large lateral adhesion coefficient are used to ensure that the vehicle does not have unsafe conditions such as locking and towing, losing steering ability, and improving the steering stability and safety of the vehicle and reducing the braking distance. The Drive Anti-Slip System (ASR), also known as the Traction Control System (TCS or TRC), is a perfect complement to ABS. It prevents the drive wheels from slipping during start-up and acceleration, which helps to improve the traction performance of the car while accelerating. Improve its operational stability.
3. Electronic Steering Assistance System (EPS)
The electronic steering assist system uses a DC motor instead of a conventional hydraulic booster cylinder, powered by a battery and an electric motor. Compared with the traditional hydraulic assist system, the microcomputer-controlled steering assist system has the characteristics of less components, small size and light weight. The optimized steering force and steering return characteristics improve the steering capability and steering response characteristics of the vehicle. It increases the maneuverability of the car at low speeds and adjusts the stability during driving.
4. Adaptive suspension system with timely adjustment
The adaptive suspension system can automatically adjust the stiffness of the suspension spring and the damping characteristics of the shock absorber according to the instantaneous load of the suspension device to adapt to the current load and maintain the predetermined height of the suspension. This greatly improves the stability, maneuverability and ride comfort of the vehicle.
5. Fixed speed cruise automatic control system (CCS)
In the case of high-speed long-distance driving, the constant-speed patrol automatic control system can be used, and the constant-speed traveling device automatically adjusts the throttle opening according to the driving resistance, and the driver does not have to frequently step on the accelerator to adjust the vehicle speed. In case of climbing, the speed of the vehicle has a downward trend, and the microcomputer control system automatically increases the throttle opening; when downhill, it automatically closes the small throttle opening to adjust the engine power to a certain speed. This control system is automatically disconnected when the driver changes gears or brakes.
With the world's major car manufacturers attaching great importance to car safety issues, airbag systems, driving dynamics control systems (FDR or VDC), collision avoidance systems, seat belt control, camera control, etc. have adopted a large number of new electronic technologies. .
Automotive electronics technology development trend
At present, automotive electronics technology has entered the stage of optimizing the overall relationship between human-automobile-environment, which is developing toward the miniaturization of ultra-micro magnets, ultra-efficient motors and integrated circuits, and provides a basis for centralized control on automobiles (eg system Centralized control of motion, steering and suspension and centralized control of the engine and transmission). Automotive electronics technology is the future of the automotive industry. In the future, automotive electronics technology should make breakthroughs in the following aspects.
Sensor technology
Due to the diversification of automotive electronic control systems, the variety and number of sensors required for them are increasing. For this reason, it is necessary to develop new, high-precision, high-reliability and low-cost sensors. Future intelligent integrated sensors not only provide signals for simulation and processing, but also amplify and process signals. At the same time, it can automatically perform time drift, temperature drift and nonlinear self-correction, and has strong resistance to external electromagnetic interference, ensuring that the quality of the sensor signal is not affected, even under particularly severe conditions of use. Higher precision. It also has the advantage of being compact and easy to install, thus protecting it from mechanical properties.
2. Microprocessor technology
The advent of microprocessors has revolutionized automotive instrumentation. The world's automotive industry has seen a surge in the use of microprocessors. From a single instrument to a multi-purpose, intelligent instrument, not only can the car be accurately placed. The to-be-measured is detected, and the required results are displayed and printed separately, and functions such as calculation, judgment, prediction, and guidance are also performed. If you can monitor the working conditions of the major parts of the car, you can also alarm the high and low limits of the battery voltage, tire pressure, and vehicle speed. Microprocessors will be more widely used in safety, environmental protection, engine, drive train, speed control and fault diagnosis.
3. Software new technology application
As the use of automotive electronics technology increases, so does the need for control software and may require further computer networking. Therefore, a variety of software is required, and a common high-level language is developed to meet the requirements of various hardware. Multi-channel transmission networks on cars will rely heavily on software, and the increase in the total number of software and its improved functionality will enable computers to perform increasingly complex tasks.
4. Research and application of intelligent car and intelligent transportation system (ITS)
The technical issues related to automotive intelligence have been highly valued by automakers. The concept of "autopilot" in its main technology will depend on electronic technology. The development of Intelligent Transportation Systems (ITS) will be combined with multiple interdisciplinary disciplines such as electronics and satellite positioning. It can provide the driver with the shortest distance and can bypass the relative density of vehicles according to the target data provided by the driver. Driving route. It is equipped with an electronic map that shows the road ahead and uses satellite navigation. From the global positioning satellites to obtain weather, traffic flow, traffic accidents, traffic jams and other conditions along the way, automatically screen out the best driving routes. One day in the future, the road will be driven by a computer-controlled smart car.
5. Multi-channel transmission technology
Multi-channel transmission technology will gradually enter the practical stage from the laboratory. With this technology, each data line becomes a network to separate the information of the car center computer. The microprocessor can receive signals from other units over the network. There is a new interface between the sensor and the actuator to interface with the multi-channel transmission system.
6. Electronic new technology application in data transmission carrier
Automotive electronics technology will realize the vehicle control system in the future. This system requires a large and complex information exchange and control system. The capacity of the computer for the vehicle is greater and the calculation speed is higher. Due to the increasing number of computer control systems for automobiles, the adoption of high-speed data transmission networks is increasingly necessary. Optical fibers can provide a transmission medium for this transmission network to solve the problem of electromagnetic interference prevention of electronic control systems.
7. Automotive in-vehicle electronic network
With the increasing use of electronic control devices in automobiles, data communication between in-vehicle electronic devices is becoming more and more important. It is necessary to construct an automotive in-vehicle electronic network system based on a distributed control system. The rapid exchange of large amounts of data, high reliability and low cost are requirements for automotive electronic network systems. In this system, each slave processor operates independently to control the performance of a certain aspect of the vehicle. Data services are also provided when other processors need it. The main processor collects the data of each slave processor and generates a vehicle status display. The communication controller guarantees the normal flow of data.
to sum up:
The development of automotive electronics technology and its large-scale application began in the late 1970s. From the 1970s to the 1980s, it experienced roughly three stages of development.
The first stage of development was the production of alternators, voltage regulators, electronic flashers, electronic horns, intermittent wipers, car radios, electronic ignition devices and digital clocks with lower technical starting points before 1971.
The second stage of development was from 1974 to 1982, marked by the use of integrated circuits and microprocessors under 16 bits in automobiles. Mainly includes electronic fuel injection, automatic door lock, program-controlled driving, high-speed warning system, automatic lighting system, automatic defrost control, anti-lock braking system, vehicle guidance, collision warning sensor, electronic timing, electronic transmission, closed-loop exhaust control, Electronic products such as automatic cruise control, anti-theft system, and real vehicle fault diagnosis. The most representative of this period is the development of electronic gasoline injection technology and the maturity of anti-lock braking (ABS) technology, so that the main mechanical functions of the car are controlled by electronic technology. However, the connection between machinery and electrical appliances is not very satisfactory at this stage.
The third stage of development was from 1982 to 1990. The application of microcomputers in automobiles was becoming more reliable and mature, and it was developing in the direction of intelligence. Products developed include tire pressure control, digital oil pressure gauge, anti-sleeping device, traction control, all-wheel steering control, direct-view instrument panel, sound synthesis and recognizer, electronic load regulator, electronic road monitor, cellular telephone , heatable windshield, reversing alarm, high speed limiter, automatic mirror system, road condition indicator, electronic cooling control and parasitic power control.
Since 2005, it can be said that it has entered the fourth stage of development of automotive electronics technology. The application of microwave system, multiplex transmission system, ASKS-32-bit microprocessor and digital signal processing method has enabled the development of communication and steering coordination system, automatic collision avoidance system, power optimization system, automatic driving and electronic map technology, especially It is the emergence of intelligent cars. Of course, some of the third-generation technologies are still not available.
Automotive electronics is an important symbol of the development of modern automobiles. From the price ratio of electronic equipment used in modern automobiles, the price of electronic equipment used in European and American automobiles has accounted for 15% to 20% of the price of the whole vehicle, while the price of electronic equipment currently used in China is only It accounts for 2.5% of the total vehicle price. From the perspective of sales in the world automotive electronics market, in 1991, the average cost of electronic products per vehicle accounted for only 10% of the total vehicle. In 1998, it was close to 15%, and in 2003 it has increased to 20%. It is even higher. The application of modern automotive electronic technology not only improves the power, economy and safety of the car, improves the stability and comfort of the car, promotes the development of the automobile industry, but also opens up a broader market for electronic products. Thereby promoting the development of the electronics industry. As a result of the combination of the automotive industry and the electronics industry, the development of the automotive electronics industry has already entered the fast lane.
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