Paul,
I've been looking through the Kinsler catalog and they have everything
you need to put together a dead simple, reliable mechanical fuel
injection system for not much money -- maybe less than an Ellison carb.
Constant flow fuel injection is used on aircraft piston engines and
works just like it sounds -- there is a constant spray of fuel coming
out of the injector nozzles, unlike the timed EFI and some mechanical
systems for cars.
Constant flow is not great for cars, but perfect for airplanes, because
you are running at steady-state rpm and power most of the time.
Have a look at the attached Kinsler Fuel Flow Diagram. The system works
like this: a mechanical fuel pump driven off the engine supplies more
fuel as rpm increases. It sends the fuel to a barrel valve that
distributes the fuel to the individual nozzles at the intake ports.
The barrel valve is kind of like a spider in aircraft FI systems, but it
is directly linked to the throttle, so as the throttle is opened, the
barrel valve is opened as well, allowing more fuel to flow to the ports.
Fuel metering is accomplished upstream of the barrel valve by putting a
restrictor jet in a return line that goes back to the tank. So the fuel
coming from the pump has two places to go, the barrel valve that leads
to the engine nozzles -- and the restrictor jet. The more fuel that
flows through the restrictor jet, the less fuel goes to the engine.
Leaning is accomplished by varying the size of the restrictor jet. A
bigger jet means a leaner mixture because it allows more fuel to circle
back to the fuel tank and less to the nozzles.
Kinsler has a cockpit adjustable mixture control that lets you dial
different jet sizes, as shown in the attached pictures. However, the
same thing could be accomplished with a simple ball valve, like the Home
Depot valve that Paul is implementing. It would be controlled by a
Vernier control cable. This way no fuel has to go through the cockpit.
The barrel valve is avaialble with a minimum of four ports, so you can
either put two nozzles on each P-port runner, one on each four-runner
manifold, or block off two of the ports and use one nozzle on each
P-port runner. I would use two nozzles per runner to get better
atomization. Also the fuel flow from two nozzles should be about right
for a single rotor. Same thing with the fuel flow of the 4-port barrel
valve.
You could use Paul's slide throttle with this system or you could use
Kinsler throttle bodies which already have the bosses for attaching the
nozzles. If you roll your own you have to weld up some nozzle bosses
onto the runners. Btw, the Kinsler bosses can accept both the
constant-flow and EFI injectors.
This system can be used with a turbocharger or supercharger becasue you
can run it with high pressure. You could get singificant evaporative
cooling effect by placing the nozzles close to the engine and spraying
the fuel right at the rotor. I would guess that you could probably run
10 psi of boost without having to go to an intercooler.
In a normally aspirated engine you can run it at lower pressure. It also
doesn't need heat, since icing is not possible. It provides all the
advantages of fuel injection in terms of precise metering and mixutre
distribution.
This should make for a very dependable, completely mechanical system
that is not dependent on electrical, control boxes or computers. If you
implement the flywheel magneto as well, you will have a real aircraft
engine.
You can download the Kinsler tech catalog here:
http://www.kinsler.com/catalog.htm
Regards,
Gordon.
Gordon
Very interesting. Good going.
One minor point though.
Please be advised that a ball valve is good as a shut off valve but makes a
terrible leaning valve. For example the flow curve is like a J curve. It's
design merit is in the low flow resistance when all the way open and the
ability to shut the flow off quickly. A good use would be the emergency shut
off valve. For metering you need a metering valve or commonly called a
needle valve. The needle come down perpendicular to the flow and into a
tapered valve seat. Excellent fine adjustment for gas or liquid flows.
I have lots of experience using both of these valves with corrosive gas and
liquid flows.
Doug Fir
Have you used them with a vernier leaning cable?
No problem. Just get a control cable you can twist
to adjust the needle valve. Do you have any
brands you can recommend or do we have to make one?
Paul Lamar ...No rotor no motor.
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