CDI preinjection, function - GF07.16-P-2008IC
ENGINE 647.961 in MODEL 211
ENGINE 648.960 in MODEL 220
ENGINE 648.961 in MODEL 211
The injected quantity required by the engine is divided into the preinjection quantity and the main injection quantity Preinjection is divided into two injection phases to reduce noise and pollutant emissions (double preinjection).
Start of actuation of fuel injectors
The start of actuation of the fuel injectors is calculated according to the operating point of the CDI control unit. This takes place with consideration of the following:
- Preinjection quantity
- Start of actuation of main injection
- Coolant temperature
- Engine speed
- Vehicle power supply voltage
Actuation duration of fuel injectors
The actuation duration of fuel injectors is calculated by the CDI control unit. This takes place with consideration of the following:
- Preinjection quantity
- Engine speed
Calculation of the individual injection quantities
The injection quantity is calculated by the CDI control unit using the following input signals:
- Engine load
- Engine speed
- Coolant temperature
- Charge air temperature
- Charge air pressure
- Rail pressure
- Fuel temperature
- Atmospheric pressure
Injection quantity = Preinjection quantity + Main injection quantity
The CDI control unit determines the preinjection quantity from its input signals according to performance mapping. The preinjection quantity is drawn from the injection quantity. If the resultant main injection quantity is less than a minimum quantity which is dependent on the rail pressure, no preinjection takes place.
Shutting off preinjection
Pre-injection is shut off depending on the operating point, if:
- the preinjection time is exceeded
- the engine speed is too high.
- the preinjection quantity is too low.
- the main injection quantity is too low.
- the fuel pressure in the rail is inadequate.
- the engine is switched off
| Component description for the fuel injectors | Y76 | GF07.03-P-6120IC | |
| Component description for the crankshaft position sensor | L5 | GF07.04-P-6010IC | |
| Component description for the coolant temperature sensor | B11/4 | GF07.04-P-6040IC | |
| Component description for the charge air temperature sensor | B17/8 | GF07.04-P-6050IC | |
| Component description for the boost pressure sensor | B5/1 | GF07.04-P-6051IC | |
| Component description for the rail pressure sensor | B4/6 | GF07.04-P-6210IC | |
| Component description for the quantity control valve | Y94 | GF07.05-P-6010IC | |
| Component description for the pressure regulator valve | Y74 | GF07.05-P-6020IC | |
| Component description for the hot film MAF sensor | B2/5, B2/5b1 | GF07.07-P-6000IC | |
| Component description for the CDI control unit | N3/9 | GF07.16-P-6000IC | |
| Component description for the accelerator pedal sensor | B37 | GF30.20-P-2010IC | |
| Component description for the fuel temperature sensor | B50 | GF47.50-P-2010IC |