[Diy_efi] Evaporative fuel injection (evolution of the evap carby)

[Phil Lamovie]

About 15 years ago I worked on a project that was based on the use of
exhaust heat to vaporize the fuel prior to it's "injection" into the manifold.

Some results were as expected some were astonishing.

The temperature needed to vaporize 100% of the fuel was in excess of
600 deg C.

I know that we all know how easily petrol vaporizes but we
also know that if you look inside the inlet manifold of a vehicle with a high
degree of heat transfer from exhaust to inlet such as were being built
in the 70's and 80's there was invariably a thick gooey (technical term) sludge
under the carby.

The physics were good but the engineering was bad. The engines were inline
4's and 6's with inlet and exhaust manifolds one on top of the other.

The were technically bad in so many ways it doesn't pay to base any future
work on the results.

On the other hand... the very complicated "injected" system was awesome for
it's clean burn and stability at 20:1 A/F ratio. It was capable of single digit
HC
reading in the exhaust with no cat.

What it did have was...

An exhaust heat exchanger that had a volume of 3.5 litres
A fuel "dosing" pump to feed the heat exchanger
A vapour pump to move the vapour to the...
Vapour storage tank ( about 1 litre)
An independent control system to keep it all happy
An electric element that was about 1200 watts
A starting procedure that was as complicated as a nuclear (pronounced Noo-ku-la)

    reactor.
A set of large and noisy injectors
A requirement to have intake and exhaust on the same side for packaging reasons.

As we know things have moved on since then.  Although physics hasn't changed.

The project was assassinated by the marketing and money people who wanted to
franchise the world with after market systems.

If they had gone the OEM path they could have managed the costs much better
and had proper integration with the rest of the vehicle systems.
It may have gained some traction in 2nd world arenas such as India at the time.

The US and OZ OEMs of course were already well progressed with planning their
L Jetronic + cat era. The European OEMs were already doing L-Jet on the more
expensive models.

Phil