Fuel Injection, Basic Function

1 Basic calculation of fuel mass/combustion







The current air mass/combustion is divided by 14.7 and sent to box 2. The unit is now mg fuel/combustion.

2 Compensation
In the case of a cold engine, shortly after starting, rapid load changes, knocking or high loads, the current value is multiplied by a compensation factor.

3 Closed loop
The closed loop value is used as a multiplier. The value is sent to box 4.

4 Correction for purging
Multiply by the value for purge adaptation. The value is sent to box 5.

5 Multiplicative adaptation
The multiplicative adaptation value is used as a multiplier and the new value is sent to box 6.

6 Additive adaptation
The additive adaptation value is added and the new value sent to box 7.

7 Starting fuel quantity
If the engine has not yet started, starting fuel is selected. The value is sent to box 7.

Fuel quantity/combustion to be injected







The fuel quantity/combustion is the amount of petrol to be supplied to the engine. The value is sent to box 9.

9 Injector opening duration
Converts the value to the time during which the injector must be open and the new value is sent to box 10.

10 Injection twice/combustion
Injection takes place twice/combustion until the camshaft position has been found. Injection duration is divided by two. The value is sent to box 11.

11 Voltage dependent needle lift duration added
Adds the injector time delay, which is voltage dependent. The value is sent to box 12.

12 Fuel shut-off
The value is sent to box 13 unless fuel shut-off is active.

13 Activation of Injector
At a determined crankshaft angle, the microprocessor will control the transistor for the injector that is next in the firing order.