The function of the automotive electronic control unit (ECU)

ECU is an abbreviation of an electronic control unit, the function of the electronic control unit is carried out in accordance with its program and data memory of the air flow meter and various information input sensors computing, processing, judgment, and then outputs the command to the injector to provide a certain width The electrical pulse signal controls the amount of fuel injected. The electronic control unit consists of a microcomputer, input, output, and control circuits.

The ECU's voltage operating range is generally 6.5-16V (regulatory device at the internal key point), operating current is 0.015-0.1A, and operating temperature is minus 40-80 degrees. Can withstand 1000Hz vibration, so the probability of ECU damage is very small, in the ECU CPU is the core part, it has the computing and control functions, the engine is running, it collects the signal of each sensor, the operation, and operation of the The result is a control signal that controls the work of the controlled object. It also implements memory.

The electronic control system of the electronically controlled gasoline injection engine consists of three parts: the electronic control unit ECU, sensors and actuators.
The ECU is like a "headquarters" of features. The function of the command is to make decisions and command the men and women of their subordinates to charge forward. To make the right decisions depends on detailed information. In order to obtain such information, we must send "scouts."

The scouts are the eyes and ears of the command. They use two main reconnaissance methods. The first is the study of external signals, such as the internal information obtained through the study of the material exchange between the enemy's camp and the outside (such as the input of vegetable foods or the discharge of household waste); The second is to send "undercover" into the enemy camp and obtain internal information directly.

The eyes and ears of the ECU are sensors. The ECU's intelligence is also divided into two categories, one is a switch, which is an external signal; the other is a process, which is internal information. The acquisition of the external signal is relatively simple and only needs to obtain the corresponding switch information. Such as electronic fuel injection system, you need to obtain the start switch signal to determine whether it is currently in the start state.

Similarly, it is necessary to obtain the neutral switch signal, air conditioning switch signal, etc., and the work of the sensor is mainly to act as an "undercover" to obtain process information during operation. They have a variety of "arms" and work in different ways. They are mechanical, electromagnetic, heat-sensitive, pressure-sensitive, and light-sensitive. Like human scouts, they have to be "behind the enemy" and are installed on working parts, possibly at high temperatures. , high pressure, corrosive dust pollution work. Therefore, they must be "elite", able to resist harsh environments and work accurately and effectively.

For humans, the same information can be obtained in different ways. For example, it can be seen through the eyes, ears, and hands. No matter what method is used, it is ultimately transmitted to the brain through the biological power of neurons. In the same way, cars can use different sensing methods for the same kind of process information, and finally transmit them to the ECU in the form of electrical signals.

For example, if the electronic fuel injection system controls the mixture concentration according to the current intake volume and operating conditions, it is necessary to obtain information on the air flow rate. I believe that everyone is not unfamiliar with the flow sensor. The water meter in the home is a water flow meter. It is driven by flowing water to push the leaves to count. It is through the calculation of the pulse frequency can know the frequency of the vortex, and thus get the flow rate of air.

In short, these sensors are each responsible for their positions. They constantly transmit signals to the ECU while the vehicle is running. The ECU constantly modifies the injector fuel according to the stored data and signals, so as to achieve the best air-fuel ratio of the mixture. .