The event-driven and responsiveness of the car engine and other intelligent components of the car are all collected by different data sensing elements, and then transmitted back to the engine’s electronic control unit, also known as the ECU, through the transmission line. After the electronic control unit summarizes and analyzes the data, it generates new instructions, and finally sends the instructions to the actuators that respond to the instructions through the transmission line for execution. This is the basic principle that the engine fuel system can inject on time, the spark plug can ignite on time, and the accelerator pedal can be ready to control the amount of oil. This series of precise control is inseparable from the engine’s electronic control unit ECU.
Which sensors does the engine electronic control unit ECU use to issue different commands?
1. Throttle position sensor, there is a throttle position sensor on the throttle. It is responsible for converting the throttle opening and the speed of the opening change into a voltage signal and transmitting it to the electronic control unit to calculate the amount of fuel injection.
2. Intake temperature sensor, at the other end of the throttle body, there is an intake temperature sensor, which is used to measure the intake temperature. Air at different temperatures has different masses when the volume is the same, and the oxygen content is also different. Therefore, the electronic control unit can correct the injection amount according to the intake temperature to obtain the best air-fuel ratio.
3. Camshaft position sensor, its function is to collect the rotation angle of each cam on the camshaft to identify whether the cylinder is in the compression stroke to determine the ignition time of the spark plug and the injection time of the injector.
4. Knock sensor, it is responsible for detecting the combustion and explosion intensity of the engine, so as to effectively send the knock of an engine. The combustible mixture accumulated in the cylinder explodes and burns in an instant, causing the pressure and temperature of the gas in the cylinder to suddenly increase several times, resulting in a sharp knocking sound, which will cause the engine to overheat and reduce power, and in severe cases, it will also cause deformation of the machine parts. This is deflagration.
5. Crankshaft position sensor, which is responsible for detecting the rotation angle of the crankshaft and the speed of the engine. The rotation angle can determine whether the piston is at the top dead center position. Combined with the data of the camshaft position sensor, it can accurately identify when to ignite which cylinder.
6. Water temperature sensor, which has similar functions to the intake air temperature sensor, is generally installed in the pipeline of the cooling system and is responsible for monitoring the temperature of the coolant. By identifying the temperature, it can judge the operating conditions of the engine to decide whether to adjust the oil and gas supply.
7. Oxygen sensor, which is installed in the exhaust pipe to detect the oxygen concentration in the exhaust gas. The higher the oxygen concentration, the less complete the cylinder combustion. The electronic control unit can adjust the injection amount, thereby controlling the air-fuel ratio of the mixer in the intake manifold within a reasonable range.
8. Throttle position pedal sensor, its function is to control the opening of the throttle. When the driver steps on the accelerator pedal, it actually transmits a throttle pedal position signal to the electronic control unit. The electronic control unit calculates the opening of the throttle based on this signal. The larger the opening, the more air enters.
Summary:
The data from all the above sensors are the basis for the engine’s air supply, fuel supply, injection control and ignition. The sensors convert these data into voltage signals and transmit them to the electronic control unit through wires. The electronic control unit calculates and processes them to obtain accurate and correct action instructions, which are then transmitted to various actuators via wires, ultimately achieving fuel injection, ignition and precise oil control.