1 Fuel injector
2 IDM or PCM
3 KS
4 Pilot injection and main injection
The KS sensor registers increased vibrations arising as a result of increased combustion noise.
The signal is used by the IDM as a correction factor for adapting the fuel quantity for pilot injection and for the main injection.
Correcting the amounts of injected fuel adaptively minimizes combustion noise over the entire service life. Note: The range in which pilot injection can be carried out is restricted by physical/mechanical limits. This means that pilot injection is deactivated above a specific engine speed and/or engine load has been reached.
Effects of faults
Open control loop:
โข If the control reverts to open loop then the pilot injection is switched off, which will result in louder combustion noise being audible.
Short circuit:
โข If there is a short circuit, the engine cuts out. It is possible to start the engine, but it cuts out again after a short while.
Diagnosis
The monitoring system checks:
โข the sensor for short circuit to ground/battery and open control loop.