Staged fuel injection uses the Hondata Injector Driver to control a second set of injectors. The second set of injectors can be larger than the primary injectors and are triggered by rpm/load or duty cycle conditions. The advantage of this over running the secondary injectors constantly is that the primary injectors can be sized to give good fuel atomization, which gives better driving characteristics and fuel economy, or a different fuel system can be used for the secondary injectors.
Staged Injection
Staged Injection - enables staged injection operation
Secondary Injectors
This specifies the size and dead time characteristics of the secondary injectors.
It is important to use accurate values for the injector size and dead time. To test the values, set the activate rpm and load to a low value (3000 rpm, 10 kPa) and free rev the engine slowly until the secondary injectors activate. If the lambda goes rich or lean, then the size or dead time values are not correct. Generally the dead time parameters make a larger different at light loads, and need to be accurate without 0.05 ms.
Activation
The secondary injectors can be activated by rpm & load or by duty cycle. It is recommended to use rpm & load for testing and duty cycle for final operation.
Rpm & Load - specifies the minimum rpm and load for the secondary injectors to operate. Hysteresis is built in to prevent rapid cycling.
Duty Cycle - specifies the minimum duty cycle for the primary injectors for secondary injector operation. Because the duty cycle will decrease once the secondary injectors activate, the deactivation duty cycle needs to be much lower than the activate duty cycle.
Switchover fuel
When the secondary injectors first switch on, a certain amount of the fuel will stick to the intake port walls and not enter the cylinder. This is especially apparent with intake manifolds which mount the secondary injectors so they do not fire into the cylinder head. Because less fuel enters the cylinder at first, extra fuel can be added when the secondary injectors are first activated.
Fuel Value - the amount of extra fuel to add, in percent.
Fuel Timer - the length of time to add extra fuel.
To tune the correct Fuel Value and Timer settings, set the Fuel Value to 0 and then datalog the secondary injector activation using a wideband lambda meter. If you see a short lean period (around 0.25 to 0.5 seconds), then increase the Fuel Value settings until the wideband does not show any lean dip. The Fuel Timer value also affects the activation fuel.
Output Control
The Hondata Injector Driver hardware is controlled by an ECU output.
Output Control - specifies the ECU output pin used to control the Injector Driver.