Shutting fuel off whie driving.

[steve ravet]

"David A. Cooley" wrote:
> 
> >Flashing at this rate would not appear as constant.  However, the pulse
> >width at idle would be so short that we might not even see it flicker.  In
> >fact, the duty cycle will always be so low (12.5% max on 8 cyl) that the
> LED
> >will only ever appear dimly lit at best.
> >
> >
> 
> When we talk duty cycle on any engine's injectors, is it the percentage of
> open time to time between intake events or percentage of open time to closed
> time regardless of RPM etc...
> Reason I ask, is if my V6 is at 5200 RPM (see's it at least once a day!)
> then it is running 5200/60/2 43.3 intake cycles per second or intake events
> every 23.1ms.  With a 23.1ms injector PW, that would be 100% duty cycle
> correct?

Yes.  duty cycle is always "on time" as a percentage of "on time" plus
"off time".  The fact that it's a car, and there's some kind of intake
event somewhere, does not bear on making duty cycle measurements.  the
sum of on+off time does change with RPM, but the formula on/(on+off)
doesn't change.

--steve

-- 
Steve Ravet
steve.ravet at arm.com
Advanced Risc Machines, Inc.
www.arm.com