Sequential injection.

[Martin Hill]

> 
> Let me see if I got it right: It's better to inject the fuel when the inlet
> valve is NOT open (I accept that but would like to know why). But if I
> start injecting soon after the inlet valve closes than at idle (when you
> inject just for a little time) the fuel would be "sitting there" for almost
> two revolutions (and for a long time because the engine is running slowly).
>  Because of this fact, couldn't another cylinder "steal" part of that fuel
> for itself ? And part of the fuel would stick to the walls of the intake
> system, wouldn't it?
> 
> If I could control when the injector is turned off so that it always turns
> off when the inlet valve is soon to open than I would have the most
> efficiency? Am I correct?
> 
> Why shouldn't I inject fuel when the inlet valve is already open?
> 
> Jose Rublescki
> 

Sorry, it was me not thinking straight.  You ideally want to time 
your injections so that it finishes just before the inlet valve 
opens. You are correct there.  By injecting onto the back of a closed 
valve which is quite hot, you get better fuel vaporisation and 
therefore better emissions. You have to have your fuel injection 
system work backwards from when you want to end your injection to 
work out the start time.  Ideally you will update the end time during 
the injection, this gives better throttle response, so you want to 
leave a bit of space after your inection should finish before IVO to 
allow room for shifting of the end point.

Martin