Air is drawn in by the engine through the air filter and flows through the mass flow meter (flow meter). The body of the flow meter contains a thin plate heated by electric current, which is cooled by the intake air flow washing it. To keep the temperature of the hot plate constant, the control electronics regulates the filament current. For example, if the amount of intake air increases, then the heated plate starts to cool down. In response to this, the filament current immediately increases so that the temperature of the plate remains unchanged. The control unit of the DME determines the load mode of the engine from the change in the heating current. The control unit, in accordance with the instantaneous air consumption and the instantaneous speed of the crankshaft, regulates the duration of injection and thus the amount of injected fuel. With a longer opening of the valve injector, more fuel is injected. Correct metering of the amount of injected fuel in any driving situation is ensured by signals from additional sensors.
Fuel injection is carried out sequentially in time. This means that the valve injectors are individually controlled and inject fuel into passages ahead of the engine's intake valves according to the firing order of the cylinders. By selecting the timing of the start of injection in relation to the opening phases of the intake valves, the exhaust gas and output parameters can be precisely matched. The engine responds instantly to acceleration.
The throttle angle sensor is located directly on the throttle shaft. It sends a signal to the control unit about the instantaneous position of the throttle. Thanks to this, in particular, the control of the fuel supply slide switch is carried out, namely: as long as the throttle valve is closed and at the same time the crankshaft speed exceeds a certain value, the control unit blocks the fuel supply to the engine.
The turnip of the fuel pump is located in the turnip box behind the arch of the left suspension strut. The relay provides current to the fuel pump. By disconnecting the battery, the relay interrupts the power supply to the pump when the engine is not running, for example, when the engine has stopped.
The instantaneous position of the engine crankshaft and its speed are determined by two inductive sensors: the speed and reference signal sensor is located at the crankshaft belt pulley. The cylinder identification sensor is located on the front of the engine chain cover.
Two oxygen sensors measure the oxygen content in the exhaust gases in vehicles with a variable catalytic converter and send corresponding voltage signals to the control unit. In accordance with this, the control unit changes the qualitative composition of the air-fuel mixture so that the exhaust gases burn out optimally in the catalytic converter.
The idle air control regulates the amount of air flow during idle bypassing the throttle. This achieves an engine speed that remains constant regardless of whether power consumers such as the power steering pump or the air conditioning compressor are switched on.
The control of the solenoid valve of the fuel tank ventilation system is carried out depending on the operating conditions of the engine. Gasoline vapors formed in the fuel tank accumulate in a container with activated charcoal and through the valve enter the cylinders from there and burn out. Thanks to this, only a small amount of harmful substances enters the atmosphere and, in addition, fuel is saved.
The automatic camshaft position control system, called VANOS for short, thanks to the pressure in the main oil line, rotates the intake camshaft relative to the sprocket depending on the engine speed and engine load, so that optimal valve timing is ensured in terms of improving idling comfort, the nature of the change in torque and fuel consumption. The DME system controls the oil flow to the VANOS actuator via a solenoid valve.
Ignition voltage monitoring system when ignition voltage is too low (for example, due to damage to high voltage wires) disables the DME system, making it impossible to start the engine. This avoids damage to the catalytic converter.
Communication with other control units (ABS, AES, automatic transmission control unit) is carried out using a special CAN data bus. This system, among other things, has the advantage that the engine wiring harness has fewer wires, and the vehicle is less likely to fail due to the failure of individual control units.