Fuel injection is performed by a fuel injector, which is mounted in the center top of the injector. The fuel injector is controlled by the electronic engine control unit (ECU). When the fuel injector is open, fuel under pressure enters the intake manifold. The fuel injector is controlled by voltage of varying magnitude. High voltage is required to open the injector, and low voltage is required to hold the injector open.
The air-fuel ratio is controlled by the ECU control motor based on data from sensors installed on the engine. Manual adjustment of the mixture quality is not possible. The throttle control motor (mounted on the side of the injector) regulates the idle speed in response to signals received from the ECU. If the throttle position sensor indicates that the throttle is closed, the ECU switches the engine to idle speed. The ECU maintains the idle speed and makes minor adjustments as needed depending on the engine load.
The idle speed can only be adjusted by a fuel injection system specialist with the necessary equipment. To prevent the engine from running from pre-ignition when the engine is turned off, the ECU sends a signal to the throttle control motor, which completely closes the throttle valve and then returns it to the position required to start the engine. When the ignition is turned on before starting the engine, the throttle control motor moves it to a position that ensures normal engine starting The ECU is the main unit of the engine management system, which controls the fuel injection system, ignition and exhaust emissions The ECU receives information from various sensors and determines engine temperature, speed and load, as well as the amount of air entering the engine.
The sensors also provide the ECU with the relative position of the throttle valve, the temperature of the air entering the engine, and the oxygen content of the exhaust gases. Based on the information received from the sensors, the ECU determines the fuel injection period. Information about the crankshaft speed is transmitted to the ECU by the crankshaft angle sensor. The sensor is an inductive pulse generator located on the cylinder block, which induces a signal when the ridges pass between 36 holes located on the inside of the flywheel.
Because each ridge passing the sensor induces a signal that is used by the ECU to determine the engine speed. The ridges between holes 35 and 36 are missing, which results in a missing signal to the ECU. As a result, the ECU determines the position of the crankshaft. A temperature sensor is used to determine the engine temperature. This is a thermistor (negative temperature coefficient), a semiconductor whose electrical resistance decreases as the temperature rises.
Information about the temperature of the air entering the engine is transmitted to the air temperature sensor, which is a thermistor with a negative resistance coefficient. The throttle position sensor is mounted on the end of the throttle shaft and transmits a constantly changing analog voltage signal to the ECU. corresponding to the opening of the throttle valve. The vehicle speed is determined by the speed sensor. which is mounted on the speedometer drive. The absolute pressure sensor measures the vacuum in the intake manifold and transmits this information to the ECU to determine the engine load at any throttle position. If there is a power steering, a pressure sensor installed in the steering system is used. The ECU increases the idle speed until the pressure in the steering system reaches the required value. The oxygen sensor is located in the exhaust system and serves as feedback, on the basis of which the mixture quality is adjusted in order to ensure optimal conditions for the catalytic converter.
Precautions
Do not start the engine with loose terminals on the battery. Do not disconnect the battery while the engine is running.
When charging the battery from a charger, disconnect both battery terminals from the vehicle's electrical system. Do not use a quick charger to start the engine. Remove the electronic control unit at temperatures above 80°C (drying after painting).
Do not disconnect or connect the electronic control unit connector with the ignition on. When checking compression, disconnect the power supply to the fuel pump relay. The fuel system is under pressure. Therefore, before replacing system parts, it is necessary to relieve the pressure. If the engine has not been running for several hours, the pressure in the fuel system will drop by itself.