On M4R engines, there is no TDC sensor on the camshaft of the piston of the first cylinder, so the synchronization of the control of the system elements with the engine workflow is carried out according to the program using the TDC sensor signals. The engine is started in semi-sequential mode (to synchronize the control of system elements with the working process of the engine), then enters the serial synchronized mode.
The injection system controls the activation of three warning lights and the display of messages according to the severity of the detected faults in order to determine the necessary diagnosis.
The injection ECU controls the warning lights and messages on the instrument panel. These warning lights come on during the starting phase of the engine, and also when there is a malfunction in the injection system or the engine overheats.
Commands to turn on signal lamps are transmitted to the instrument panel via the multiplex network.
Camshaft Phase Control
The valve timing smoothly changes from 0 to 43°according to the angle of rotation of the crankshaft. The phase regulator is controlled by a solenoid valve, which is energized in the form of a variable signal of the degree of cyclic opening from the injection computer.
Control of the electric fan of the engine cooling system and signal lamp of the emergency coolant temperature
The request comes from the injection computer via the multiplex network (centralized coolant temperature control function). The supply voltage is supplied to the electric fan from the protection and switching unit.
Air conditioning compressor control
The request comes from the injection computer via the multiplex network. The request is generated on the basis of data on the operation of the air conditioning system, as well as taking into account the temperature of the coolant. The air conditioning compressor is powered through the protection and switching unit.
Fuel pump control
The request comes from the injection computer. The supply voltage is supplied to the fuel pump from the protection and switching unit.
Oxygen sensor
Two oxygen sensors are used, installed at the inlet and outlet of the catalytic converter.
Throttle block
Air supply and idle speed are controlled by a servo throttle body.
Protection and switching unit
The unit supplies power to the following units:
- ignition coils;
- fuel pump;
- air conditioning compressor;
- electric fan;
- some injection system actuators (nozzles, canister purge solenoid valve, etc.).
The protection and switching unit is located in the engine compartment next to the battery. The unit provides protection for the circuits of some electrical appliances.
To perform this function, the unit includes fuses and several built-in relays:
- relay «+» after the ignition lock;
- fuel pump relay;
- air conditioner compressor relay;
- relay of the electric fan of the engine cooling system;
- starter relay (starter relay control).
These relays are non-removable.
Accelerator pedal
The reference value for the engine ECU is the signal from the accelerator pedal sensor.
The sensor is made in the form of a two-track potentiometer. The signal voltage from the sensor has two conductive paths with different resistance.
Voltage is applied from the first conductive track (0-5V), twice the signal voltage from the second track (0-2.5V).
Comparing the voltage of both signals makes it possible to verify that the generated signal corresponds to the current value.
Idle mode
Idle speed increases by no more than 160 rpm if the battery voltage is below 12.7 V.
In the event of a present and stored MAP sensor fault, the idle speed setpoint is set to:
- 896 rpm (K4M engine),
- 1024 rpm (engines H4J, M4R).