Automotive ECU development process Chengdu Panfeng Technology

Taking the engine development process as an example, a brief introduction to the automobile development process. Introduction to Chengdu Panfeng Technology
With the advancement of technology, automobiles are becoming more and more digital. At present, automotive electronic information products have accounted for an average of 1/2 of the total cost of automobiles, and this ratio is still increasing. Some experts believe that this ratio will reach % in the next year. For example, a mid-range sedan like Bora has at least a dozen automotive electronic control units. The so-called is actually an embedded system with a microcontroller, which has its own processor, equipment and memory, and can independently control a certain system of the car, such as the engine management system and systems. As for high-end cars, they often have dozens or even hundreds of them connected together through a digital bus structure to form a complex computer local area network.
Car development process
The car development process is shown in the figure.
. Cyclic approach to automobile development
.. Design calculation
The purpose of the engine matching project design calculation is to determine the types and parameters of components such as the engine and transmission according to the performance required by the car. It is divided into the following methods.
Manual calculation
Mainly based on the balance diagram of the car's driving force and driving resistance to determine the car's maximum speed, acceleration ability and climbing ability in different gears to evaluate the impact of different transmission ratios on the car Performance influences determine engine and transmission parameters. The calculation of this method is cumbersome and the result is not accurate enough.
Simulation calculation
Based on the design of the car and each component model, input the performance parameters of the engine and transmission and other car components and the entire vehicle, specify the required driving cycle, and finally calculate the power, economy, and emissions of the car. performance and braking performance. It can display and print various analysis reports and chart results on the computer, calculate quickly and accurately, and reflect the impact of changes in any parameters in the automotive system on the performance of the entire vehicle. At present, the common commercial vehicle simulation software in China is the vehicle performance simulation analysis software developed by Austria-based Liszt Internal Combustion Engine and Test Equipment Company.
Parameter optimization
Use the car's power, economy, emission performance and braking performance as the objective function, and use parameters such as engine power, car weight and transmission ratio of each gear as optimization variables within a certain range. Seeking the optimal matching combination to achieve the best performance-price ratio of the car.
.. Engine and transmission layout
After completing the engine matching design calculation, one or more engines and transmissions can be selected from the market based on the initially determined calculation parameters and car layout, and then the corresponding selection and development Components such as braking, steering and air conditioning systems are trial-arranged in the engine compartment and body. You can also build a 3D digital model of the car and components and test the assembly in the 3D software environment to check the interference and make adjustments. After determining the location of the main components of the car, follow-up work can be carried out.
. Development of engine accessory systems
Usually automobile engine suppliers only provide basic engines or engine bases, which lack some peripheral accessory systems and therefore require automobile manufacturers to develop these systems. These accessory systems include: fans and fan clutches, intake and exhaust ducts, air filters, engine oil pumps, engine mounts, power steering pumps, three-way catalytic converters, air conditioning compressors, and fuel supply systems.
. Design and Analysis
.. 3D Design
In the development process of modern automobiles, 3D software is required to design digital models of automobiles and components.
The main automobile design 3D software is: American company's, American r company's r/, French (Dassault) company.
The main D modeling methods include: feature modeling and reverse scanning with a three-dimensional coordinate measuring machine.
.. Analysis
The main automotive analysis software includes: (Anshi) Co., Ltd.'s series software, r company's d, and series software, the company's, and series noise analysis software.
The analysis projects in the engine matching project include: engine noise and vibration analysis, engine support analysis, engine thermodynamic analysis, automobile collision analysis, and computational fluid dynamics analysis (verification of the size of the radiator and engine intake flow characteristics) .
. Main test items
The main test items include: engine and automobile bench test, engine noise and vibration test, engine mount vibration frequency measurement test, exhaust system durability test, engine filter and pressure and flow testing of cooling systems.
Engine electrical matching technology
. Engine management system and its development technology
.. Engine management system
The engine management system is the basis of the engine electronic ignition and electronically controlled gasoline injection system An integrated circuit system developed on the Internet that integrates electronic control injection, emission control, electronic ignition, starting, anti-theft, diagnosis and other functions. Achieving precise and flexible control of various engine systems is the main means to improve engine performance indicators and emissions. The engine management system consists of a microprocessor, various sensors, and actuators. The sensors detect various working conditions and parameters, and then the microprocessor issues instructions to each actuator to complete various actions to make the engine operate at various times after calculation, analysis, and judgment. Can work at its best under all working conditions.
.. Engine management system development technology
Engine management system development technology involves computer technology, automatic control, embedded systems, engine technology and other fields. It is the most complex system in automobile electrical control systems. Development work currently not required by car manufacturers in matching engine systems. This is because the basic engine usually provided by the engine supplier is already equipped with a ready-made engine. The car manufacturer only needs to contact the corresponding developer for calibration work.
The current popular development process is to use visual and modular methods to build an engine control model on a simulation computing platform. After successful debugging, it is compiled into machine execution code and then downloaded to the car. For example, the engine and vehicle control system development tool launched by British Technology Company provides a solution for automatic code generation and rapid prototyping. Its application range includes engines, transmissions, chassis and hybrid control systems, and automotive mass production systems. The platform can automatically generate control code in the environment and then run it in the car.
. Engine calibration technology
.. Engine calibration
The engine calibration test refers to the continuous debugging of the parameters of the engine management system under different working conditions and climate environments of the car to find the best engine Testing technology for a set of parameters under working conditions. It is usually divided into indoor bench test and outdoor road test. Outdoor road test is required to be carried out at the car test track. In addition, three high tests of high cold, high temperature and high altitude are also required. The main tools for engine calibration testing are engine calibration software and engine calibration equipment.
Usually the control algorithm software inside a certain model of engine is fixed, but the thousands of free parameters it contains are adjustable. For different models, these parameters need to be debugged and optimized through engine matching calibration to make the whole vehicle pass Various emission and drivability indicators.
Matching calibration is a complex system engineering. It includes bench tests, controlled environment laboratory tests, calibration calculations based on mathematical models, emission tests, functional verification tests, etc. During the entire project process, various advanced calibration tools (hardware equipment and computer software) must be combined into a seamlessly connected calibration system, including communication, software programming, calibration parameter management, online calibration, temperature acquisition system, and simulation data acquisition system. wait.
.. Engine calibration software
The engine calibration software has the ability to collect test data from engine sensors and then write (or download) it to the car after technical processing. At the same time, due to the need to process a large amount of test data during the calibration test The engine calibration software has powerful database management functions. As the functions of modern engines become more and more complex, the control parameters have also increased sharply from the initial dozen to the current thousands, which has led to a geometric increase in the number of tests. It is impossible to perform tests that require permutations and combinations of all working conditions for each calibration parameter. Therefore, calibration software based on test optimization technology has also emerged, such as the model-based calibration toolbox () launched by r company, which can optimize the test plan, reduce the number of calibration tests, reduce test costs, and shorten the test cycle.
.. Engine calibration equipment
During the engine calibration test, it is necessary to measure various physical quantities such as the engine's speed, temperature, and pressure. In addition, the calibration data generated by the calibration software needs to be written into the car. The engine calibration equipment can achieve this. Function.
.. Engine calibration test
The engine bench calibration test items include: engine actual charging efficiency, air-fuel ratio, ignition timing, basic engine thermal engine calibration. The vehicle calibration test items include: vehicle exhaust emission control, Vehicle drivability, tropical environment, plateau environment, cold zone environment, vehicle parts fault diagnosis system calibration and system verification.
Conclusion
At present, many development technologies in the field of engine matching still require the help of foreign companies to assist in completing some technical concepts, which are also blank in automotive textbooks, such as the development and calibration technology of engine management systems. The author hopes that this article can serve as a starting point and provide reference for domestic automobile manufacturers to develop new models.