The amount of fuel injected is proportional to the injector duration (opening time), fuel rail pressure, fuel temperature and fluid. viscosity. A target value for injector duration under specific conditions is programmed into the control unit (ECU) engine control map.
A target value for injector duration under specific conditions is programmed into the control unit (ECU) engine control map.
The fuel injectors are machined to very fine tolerances but because of individual characteristics such as friction, pressure drop, magnetic force, wear during service etc, very slight variations in flow can occur.
Slight difference between target flow and actual flow can occur due to high operating pressures.
Certain common rail diesel fuel injectors require calibration during manufacture or overhaul on a specialised diesel injection test rig to produce a data code relating to the characteristics of each individual injector.
This data code allows the engine control module to correct the pulse duration applied to each individual injector to maintain optimum performance. Fitment of replacement injectors will require the
new injectors to be coded to the engine control unit.
