Racing technologies: Electronic Control Unit
Hello dear colleagues!
Today I would like to talk about electronics that I work with in my spare time, namely it is a racing car engine control.
Let's start describing the situation as a whole. In the car racing often the result does not depend only on a sportsman as in many other sports, but also it depends upon the equipment that sportsman uses. So, there is needed a professional approach to training and tuning up the racing car. Of course, there are a lot of nuances. But if we roughly divide this into the parts, we will get the chassis adjustment and engine tuning. Today I would like to tell you what electronics is used to tune up the engine of racing cars.
The modern racing engine (and the engine in your car) is controlled by a specific computer: Electronic Control Unit. It controls all processes that are going on inside and all on-board electronics. The most popular solutions are manufactured by the companies, such as Motec and Pectel. I am using in my car Motec M800, which is going to be as an example that I will discuss how it works.
In fact, ECU is a computer, which is programmed by the algorithms to control the engine, and it has the tools for collecting information and the ability to control external devices. In terms of algorithms a four stroke petrol engine is a very simple device that is easily controlled by it. We will need some knowledge about the speed and reference mark sensor and the throttle position sensor. Also, we need to know how much air enters into the engine. To do this we use a MAF (Air Flow) or MAP (Air Pressure) sensors. As control elements we will use the fuel injectors and control the ignition coils. Whatever I have listed above will be enough to start the engine. The collected data allows ECU to inject the fuel to turn on the ignition when it is needed. But the question remains, how much fuel is needed and when to turn on the ignition? These data is called "firmware".
The Motec computers use Controller Area Network bus for external control. To connect a laptop there are used special adapters CAN-to-USB. As the edit program is used the ECU Manager that is available for downloading and training for free on the manufacturer's website. If you want to see how the management of running engine looks, then run WinEMP.exe demo option.
This software lets you make adjustments in almost all aspects of the engine. One of the main control parameters of the algorithms is PID controller. It displays all dynamic processes. The remaining part is implemented by the features that are described by the tables. The main feature is the ability to create a tabular dependence between any available elements. Thus, the programmer’s possibilities to program the algorithms are not particularly limited. So, having the incoming parameters and controlling external devices, you can foretell the behavior of the engine in virtually any conditions.
But it is watch quite difficult to control all components of the engine when it is running. Therefore, the concomitant process becomes collecting and analyzing the system log of ECU. Logging settings can control all necessary parameters. Therefore, it is used i2 Manager software from the same manufacturer. It analyses the sensor data. This invaluable information makes possible to tune properly all parameters.
The ECU has a set of input and output controlling ports. As input information it can accept the digital signals using CAN, and the analog information in the range of 0-12V using programmable built-in ADC. The GUI allows configuring ECU almost for any external sensor. The external devices such as the injectors, ignition and some other could be controlled through the output ports, depending on the output characteristics. Finally, this set of tools allows connecting the ECU to any car.
In general, this engine tuning process is a commercial secret of racing teams. Around this process is deliberately created complexity and mysteriousness. But I think that any competent programmer will cope with it, having understood how the engine is running.
I hope I have told you something new. Thank you for your attention.
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