fuel evaporation & injectors

Chris Conlon synchris at ricochet.net
Fri Jan 9 20:17:07 GMT 1998


Gary wrote:

> With non sequential port fuel injection, fuel puddles behind the intake
> valve.  When the valve opens, residual exhaust blows it upstream causing
> good vaporization.  Other things to try are heating the intake air and
> heating the fuel.  I believe Honda's last turbocharged Formula 1 engine
> heated the fuel to 70 degrees C.  Gasoline has an end point around 300
> degrees.  If you heat it to 150 or so, much of it will vaporize as it comes
> out of the injectors.  Heat it to 300 and you can be injecting vapor.  Under
> pressure in the fuel rail it would be liquid.  As it flowed past the
> injectors, it would flash into vapor.

Apart from the danger, & probably fried injectors, it sounds like fun!  ;)
If I get my own cone shaped hat, can I try it???  **j/k!!**

This reminds me, what's the deal with Mitsubishi's GDI (gasoline direct
injection?) engines?  Is this a diesel type setup? I can't get anything but
Mitsu's hype about more power, less emissions, more mileage.

I did talk to RC Engineering, thanks all for the suggestion. They did agree
that fuel evaporation is often incomplete, but didn't seem to see this as a
problem. (Obviously FI *does* work.)  I plan to satisfy my tweak compulsion by
putting my additional injectors either in the throttle body or just after
the supercharger, and picking very fine spray units. Good enuff I guess.

Plus I may put a temperature sensor on the fuel rail; perhaps part of the design
is that the rail itself will get pretty warm. If so, that's kinda elegant.

   Chris C.




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