Injection Duration

Injection Duration





Fuel mass per combustion
The fuel mass to be injected into the engine per combustion has been calculated. The value is divided by 0.76 and is now converted to ml petrol/combustion.

The volume is accumulated for each combustion and the value sent on the bus. The main instrument unit uses the value to correct the tank gauge and the information display uses it to calculate the petrol consumption.





Injector opening time
Fuel volume/combustion is converted to injector opening duration based on knowledge of the injector flow.

Injection twice/combustion
Before the camshaft position has been detected, injection will take place semi-sequentially at 120 degrees intervals. This means two cylinders at a time in the following order:





^ Cylinders 1+4
^ Cylinders 2+5
^ Cylinders 3+6

Each injector injects fuel once per crankshaft rotation and this means that the basic duration must be divided by two.

Needle lift compensation
The amount of time it takes for the needle in the injector to lift is voltage-dependent. Depending on the battery voltage, the delay time is added to the basic duration.





Fuel shut-off
If any of the following criteria are fulfilled, fuel shut-off will take place:





^ Power supply +15 not found
^ Fully depressed accelerator pedal while starter motor is cranking
^ Engine speed exceeding 6600 rpm
^ Immobilizer code faulty.
^ Major fault in throttle control
^ Engine braking during certain conditions
^ Cylinder shut-off upon fault in throttle control
^ Cylinder shut-off when overheating protection active

Activating the injectors





ECM controls the injector that is to deliver fuel. Sequence is governed by firing order. At which crankshaft angles injection is to occur depends on the operating conditions. The injection is divided into a pre-injection and a main injection.

The pre-injection occurs when the intake values through evaporation of the fuel toward the valve stem cap. This improves fuel preparation. The degree of pre-injection depends on coolant temperature. At low temperatures, the degree of pre-injection is null or small.

The main injection occurs when the intake valves are open. Evaporation of the fuel absorbs heat from the combustion chamber, thereby cooling the engine. This results in reduced thermal stress and reduced propensity toward knocking.

The injectors are supplied with voltage from the main relay (229) and are grounded by the control module as follows:
^ Injector 1 is regulated from pin 63(A)
^ Injector 2 is regulated from pin 62(A)
^ Injector 3 is regulated from pin 46(A)
^ Injector 4 is regulated from pin 45(A)
^ Injector 5 is regulated from pin 47(A)
^ Injector 6 is regulated from pin 64(A)