I've read that the opening time of fuel injectors decreases (to a point) the higher the voltage is across the injectors. The voltage available is more or less the battery / charging system voltage.

If put a zener diode (or even a 3 terminal voltage regulator) between the battery voltage line and ground, this would keep the voltage at one value (except in states of severe battery discharge) and keep the open time of the injectors predictable (thus keeping the minimum usable pulse width up).

From an electronics point of view ( I don't know what the rest of the injector driver circuit looks like) is there a reason not to try something like this? I realize that the pulse width correction vs battery voltage would need adjustment.

 

Is it worth the trouble? Is the injector driver circuit not regulated already? How significant is a few microseconds of consistency compared to the total injector open time? How many other inconsistencies in the operation of the engine are there that are going to completely obscure this one?

 

Fair enough, it might not be significant. What controls the minimum usable pulse width of a given injector? Does the voltage across the injector have anything to do with it? Or is it all in the mechanical design of the injector?

 

don't think of those corrections for a steady state, in-use charging system, running down the road.

think of the application where a vehicle has been sitting for a long period and a user goes to restart it. the voltage is all over the place as the starter pulls the battery down reallllly far.

those compensations help to get fuel where it's needed fast to enable the engine to start.

additionally, it allows the designers to tweak the overall emissions and accuracy within a single table that would also compensate over the life of the vehicle.

 

A voltage regulator would set a maximum voltage, it wouldn't do anything for the starter load. Even still, it wouldn't make any difference to the time it took to start. The injector system has no trouble getting fuel where it's needed to enable the engine to start.

And what possible difference can a few microseconds of time make to emissions when the ECM is constantly adjusting the injector time to chase the cross counts of a narrowband O2 sensor?