5.2.9. EDC control system

The electronic control system of the diesel EDC engine for Common Rail includes three big systems:

  1. Sensors for registration of parameters of the operational mode which transform various material parameters to electric signals.
  2. ECU for generation of output electric signals on the basis of signals from sensors and the set algorithm.
  3. Drives for transformation of output electric signals of ECU to mechanical parameters.

Sensor of frequency of rotation of a bent shaft

1 – permanent magnet
2 – casing
3 – engine case

4 – metal core
5 – coil
6 – gear rotor

Position of the piston in the cylinder of the engine is decisive in definition of the moment of injection of fuel in the combustion chamber. As pistons through rods are rigidly connected with a bent shaft, the sensor of provision of a bent shaft transfers to the control unit information concerning position of all pistons. The inductive sensor determines the frequency of rotation of a bent shaft by angular speed, and this important entrance variable is transferred to ECU.

The ferromagnetic rotor with 60 teeths is fixed on cranked to a shaft, at the same time on a rotor there are no 2 teeth. This interval is located in a certain situation in relation to a bent shaft and position of the piston in the first cylinder. The sensor represents a permanent magnet and a metal core with the inductive coil. When passing about a pole of the sensor of teeths of a rotor in it the sinusoidal tension which amplitude increases with increase in frequency of rotation of a bent shaft is induced.

Sensor of position of the camshaft

The camshaft operates inlet and final valves and rotates with a frequency twice less than the frequency of rotation of a bent shaft. At the movement of the piston to the top dead point position of the camshaft specifies what piston is in a step of compression or a step of release.

The sensor of position of the camshaft works at Hall's effect. The short-term signal of the sensor reports to ECU that the piston of the first cylinder passed into a compression step.

Temperature sensors

1 – socket
2 – case
3 – NTC resistor

Sensors of temperature are installed in various places of the engine and intended for the measurement of temperature of cooling liquid coming to the engine of air, engine oil and which is coming back to the fuel tank of fuel. A basis of each sensor is the resistor which resistance changes depending on temperature with negative temperature coefficient (NTC). Power failure on the resistor is transmitted through the analog digitizer (ADC) to ECU. The characteristic of the sensor is written down in memory of ECU as function of tension.

Characteristic of the sensor of temperature (NTC)

Air consumption measuring instrument

1 – contacts of the socket
2 – internal connections
3 – electronic block
4 – an opening for an air admission

5 – sensor element
6 – an opening for production of air
7 – case

The system of injection of fuel is intended for exact dispensing of fuel depending on amount of the arriving air at various power setting. The proper correlation of air and fuel is necessary for reduction of amount of harmful substances in the fulfilled gases. It demands use of sensors which precisely register the actual stream of the air coming to engine cylinders at every moment.

Accuracy of the sensor should not depend on pulsations, system of recirculation of the fulfilled gases and temperature of the air coming to the engine. The air consumption measuring instrument with the heated thin film conforms to these requirements. The micromechanical measuring system registers a stream of air and its direction.