Fuel Injector Pulse width In Relation To RPM

Dears,

I want to know Injector Pulse width related to RPM diagram. Does injector Pulse width increase as we increase RPM?

I want to know PW from idle to high rpm.

Thanks for any clarification

Moved this to Diag Tools.

Not sure if such a chart is out there... :huh: It's my experience that injector pulse width is more closely related to engine load than engine speed. I can experiment with this on the Scion later.

Played with this a bit earlier:



As I was thinking, just increasing engine speed didn't generate much of a change in pulse width. BUT, doing WOT snaps got the Load PID moving, which generated longer pulse widths.

Yes engine load which basically depends on how much air is trapped in each cylinder at the start of the compression stroke. At idle speed the throttle restricts the amount of air entering the engine, this lowers the pressure in the inlet manifold (higher manifold vacuum) so the ammount (mass) of air trapped in the cylinder at the start of compression is less. The engine computer commands at short injection pulse to maintain the ideal air/fuel ratio.

At full throttle the inlet manifold is at close to atmospheric pressure so more air is trapped in the cylinder at the start of compression and more fuel is required to maintain the air/fuel ratio.

Because on a modern electronic injection injection system there is one injector pulse per firing stroke increased fuel flow for higher RPM isn't a major factor in injector pulse length.

You can observe the injector pulse length increasing if you add load at idle speed by switching on electrical loads and the AC.