idea..

[John Napoli]

I might be coming into this pretty late, but the circa-80s Jags do this.
A black box is hung off the ECU.  The speedometer is electric.  Calculates
distance traveled, avg mpg, instantaneous mpg, total fuel consumed.
Pretty accurate, too, at least in my car.

John

On Thu, 9 Oct 1997, Dave J. Andruczyk wrote:

> > 
> > So are you saying that ALL you need is the pulse width and distance sensor
> > to determine instantaneous fuel consumption? If so you're wrong. The pulse
> > width, like I said, is not what determines rate of fuel consumption, but
> > rather the duty cycle(pulse width over period) of the injector is what is
> > the determining factor. If you sum the pulse widths you get nothing more
> > than the sum of the pulse widths. This is useless for determining fuel
> > usage unless you have some sort of time base for it. So you have to either
> 
> The time base is the distance traveled. MPG = Mile Per Gallon. Pulse width
> equals a certain amount of fuel sprayed. i.e. an injector sprays .001 Gall
> per sec of open time. (hypothetical) The pulses from the wheel sensor, is
> the mileage traveled.  All the ecu needs to do is sum up the time that the
> injectors are spent "open", and count the distance traveled, from the
> pulses from the wheels, and do the calculation and save it into a
> register, somewhere for display.
> 
> Dave
> 
> 
>