Three technologies for the development and practic

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Three major technologies for the development and practicality of automotive electronic systems

[Abstract] at present, 80% of the new technologies used in automobiles come from the continuous updating and progress of electronic systems. At present, there are three technologies that have begun to enter the practical state, namely, X-by-wire technology, on-board network and 42V electric energy scheme. They complement each other and promote each other, making the level of automotive electronic technology to a new level

key words: automotive electronics X-by-wire technology can 42V energy scheme

1 introduction

in the past decades, automotive electronic systems have achieved great growth in number and complexity. Due to the extensive use of electronic components, such as various sensors, microprocessors, electric drives, etc., the cost of automobiles has greatly increased. Today, the electronic system of medium and high-end vehicles has accounted for more than 23% of the total manufacturing cost of the whole vehicle. The average cost of electronic products in a car increased from $110 in 1977 to $1800 in 2001. Automotive experts believe that 80% of the current new technologies in automobiles come from the continuous updating and progress of electronic systems. It is estimated that in the next decade, the proportion of automotive electronics and electronic technology related products in the vehicle cost will rise from the current 20% to 32%. The growth rate of automotive electronics will rise from the current 10% to 20%

due to people's pursuit of energy-saving, safety, comfort, convenience and luxury of cars, higher requirements are put forward for the performance of cars. The use of traditional machinery can no longer significantly improve the performance of cars. In recent years, with the rapid development of microelectronics technology, especially the great progress of microcomputer technology, the combination of electronic technology and traditional machinery has made the problems of environmental protection, energy conservation, safety, comfort, convenience and intelligence of automobiles well solved

the author believes that the automotive electronic technology that can be applied and is being applied at present mainly focuses on three aspects, namely the following three technologies:

(1) the development and use of electronic control technology, namely electronic control or X-by-wire technology

(2) the continuous use and popularization of vehicle network system, especially can

(3) the new voltage system 42V (V) vehicle electrical system to be adopted

the development of these three technologies, some have begun to be practical, and some are about to be put into practice. Therefore, while introducing new models with these new technologies, China also needs to have the necessary understanding and Research on these technologies, which is conducive to improving our automobile design and manufacturing level, so that our automobile production enterprises can reach the international level as soon as possible

2 X-by-wire technology

in the past, cars used to be the world of mechanical and hydraulic systems. With the continuous improvement of people's requirements for cars, especially for emissions and safety, today's cars have become a highly mechatronic automatic system. With the development of technology, this trend is becoming more and more obvious

now people often mention a noun "X-by-wire", "wire" means electric wire, "by wire" can be understood as an electronic control mode, and here "X" is like an unknown in the mathematical equation, representing various components in the car that are traditionally controlled mechanically or hydraulically, such as engine, suspension, steering gear, etc., and small ones such as throttle, door lock, etc. Obviously, in order to meet people's higher requirements for automobiles, these components controlled by machinery or hydraulic pressure are gradually transformed into electromechanical hydraulic integration control, and even into pure electronic control mode

at present, the work of replacing mechanical parts with reasonably configured electronic parts is proceeding in an orderly manner, and the performance and level of the system have also been continuously improved. The cost of advanced electronic systems is also plummeting. Complex high-performance electronic components such as chassis control and sensitive sensing have been used in advanced vehicles, and gradually become the mainstream. Figure 1 shows that the trend of electronic control in braking stability control is very obvious since 1920

the highly reliable fault-tolerant electronic control system X-by-wire does not rely on traditional mechanical and hydraulic devices, which makes the car lighter, cheaper, safer and more fuel-efficient. Its self diagnosis system and adaptation system are suitable for all types of vehicles. This system can eliminate the drive belt, hydraulic brake pump and even steering column of the car, and there will be cars without steering wheel

in fact, by 2010, 1/3 of new cars will have electronic driving systems. The X-by-wire driving system under development will replace the steering column with angle sensors and feedback motors. A serial network provides a control link to the wheel mounted actuating motor. This change in the steering column will improve driver safety in the event of a collision. It will simplify left-hand and right-hand driving parts

it is easy to add some advanced functions on the basis of this electronic system. For example, in the mechanical steering system, the driver cannot use the steering wheel correctly at high speed (e.g. steering too fast due to panic), and the electronic control method can drive the executive motor to skip this out of control stage within an appropriate range

all large automobile manufacturers are developing the prototype of X-by-wire system and its products. For example, TRW electronic assisted driving system increases fuel economy by 5%. Delphi automobile claims to have made similar improvements in e-steer system. Bosch, Valeo and other equipment manufacturers have developed or are developing X-by-wire technology and products

3 vehicle network

with the development of automotive electronic technology, there are many electronic control units in automobiles, such as engine control module (ECM), BVA computer, intelligent display screen, ABS, etc. There is a large amount of information exchange between these electronic components with microprocessors. In the past, wires were used as the standard connection of electrical components. However, with the continuous increase of electronic products, more and more connecting lines have become barriers to technological development

using the traditional harness scheme will greatly increase the length and number of wires, while the continuously lengthened harness and increased connectors increase the quality of the car, weaken the performance, and make it difficult to guarantee the reliability. For a normally running vehicle, the fuel consumption will increase by 0.2L for every 50g of harness or 100W of energy loss. Moreover, the complicated harness connectors make the voltage drop significantly, which limits the normal use of other functions, and become the most expensive and cumbersome part of the automotive electronic system

the vehicle network system is to connect electrical components to the vehicle control, just as the computer is connected to the local area. These networks can easily share information and resources, thus successfully solving the above technical problems, which is also a typical example of the successful combination of modern computer network technology and automotive electronics technology. At present, the vehicle network system has been widely used all over the world. The most widely used network protocol standard in automobiles is can (controller area network)

in the mid-1980s, Bosch Company developed this kind of control area, which is the earliest and longest used automotive control network. Can has been widely used in current vehicles. In 2000 alone, its sales of related devices exceeded 100million

a typical vehicle equipped with can can can accommodate 2 ~ 3 independent can operating at different transmission rates at the same time, and the low-speed can operates at 125 Kbps. It is usually responsible for managing "comfort functions", such as power seats, power window lifts, etc. Generally, the control without real-time requirements adopts low speed. It has an energy storage sleep mode, in which the node stops oscillating until a can message wakes it up. Sleep mode prevents power consumption

high speed can is used to meet the important control with high real-time performance. Such as: engine management, ABS, cruise. Although the maximum baud rate of high-speed can can reach 1Mbps, a very high 3 The electromechanical phase sequence is not allowed to jump large electromagnetic radiation. When the transmission rate exceeds 500kbps, the energy loss will increase rapidly. Therefore, the general high-speed is 500kbps. Figure 2 shows a typical two speed can model

Figure 2 a typical can model

4 electric energy supply and 42V scheme

with the rapid increase of electronic systems on cars, they will consume a lot of electric energy, making the total load more than 2kW. The internal energy demand will increase at a rate of 4% per year. If this trend continues, it is conservatively estimated that the average power demand of high-end vehicles will reach 2.5kW by 2005. This growth will make the current power supply system more powerful. The new factory has three 100000 grade clean rooms that produce medical grade pipelines and accessories. For example, under 3KW load, the generator with bracket and belt drive will make obvious noise, and additional cooling devices are required

Table 1 indicates the electrical energy loads that may be consumed by some important systems. Automotive experts predict that the electrical load level in 2005 will reach the specified value in the table. Table 1 load estimation of main electrical system of automobile

for a specific power, the increase of voltage value can reduce the system current in an automotive electronic system. A small current can reduce the loss on the wire, so a thinner and smaller harness can be used. Increasing the voltage value can also reduce the volume, quality and loss of the electrical device itself, and is also conducive to the miniaturization of the control device and improve the integration

the 42V electrical system requires a 36V battery with a maximum working voltage of 50V and a peak voltage of 58V. This is because 60V is the maximum safety limit considered by engineers. Higher voltage will cause harm

although the advantages of the 42V system are obvious, the conversion from the 12V system, which has been used for half a century, to the 42V system will drive the province to form a batch of new material industry clusters with prominent regional advantages and distinctive industrial characteristics. The cost of redesign and manufacturing is enormous, and the maintenance and upgrading will bring obstacles. Therefore, at present, it is more realistic to adopt a 14v/42v dual voltage scheme to reduce the impact on the auto parts manufacturing industry and realize a smooth transition

14v/42v dual voltage conversion process is as follows: the alternator outputs 42V high voltage, and with the help of a dc/dc converter (DC converter), the 42V is converted to 14V. In this system, dc/dc converter divides the power supply system into two power supply systems with different voltage levels. In addition to reducing voltage, it also plays an important role in the power distribution management of the whole electrical system

5 Conclusion

through the analysis of the above three automotive electronic development and practical technology, it is not difficult to see that there is a very obvious causal relationship between them. In order to meet people's new requirements for vehicle performance, X-by-wire technology must be widely used to realize electronic control. The development of X-by-wire technology makes the harness system too complex and overburdened. The development of on-board network system successfully solves this technical problem. At the same time, the 42V energy scheme ensures the energy supply of the first two and provides a broader space and guarantee for their development. The common development of these three complement each other and promote each other will surely bring the level of automotive electronic technology to a new level. It can be predicted that in recent years, we will often see successful applications of new models launched synchronously in China and internationally

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