Living Throttleless

[Shawn D.]

Originally Posted by thecheese429

Why not go low-tech, instead of keeping the ECU?

I had the idea of a "throttleless carburetor." It is just a throttle body with 2 jets. The jets meter their fuel by means of a tapered needle that pushes in to slow (or stop) flow, and pulls out to increase flow.

One needle has the gasoline, so whenever you push on the "go pedal" (sorry, I guess that in this application it really would be the "gas pedal") the gas needle opens. The other needle is water. It would be somewhat inversely proportional to the gas needle, so if the gas needle was almost closed (idle) the water would be injecting a good amount. If the gas needle was open (IE, flooring the pedal) the water would be injecting very little.

What you're suggesting is basically a Hilborn fuel injection setup, plus water injection. The problem with the concept is that Hilborns were made for full-throttle (or near full-throttle) use -- they worked well in that application, but are not great for driveability. Such a setup does not compensate for load or density and would be a step backwards.

Originally Posted by thecheese429

The water and gas would both have to be pressurized, so that you don't care about the Bernoulli effect sucking the fuel (and water) out, like a normal carburetor.

If you don't have a venturi, you don't have the Bernoulli principle in effect.

[usergone]

Originally Posted by Shawn D.

...but are not great for driveability. Such a setup does not compensate for load...

I wonder if it could be governed so that it works smoothly and can have a changing load (IE, driveable).

[autoteach]

I have a few questions that will make either sense or someone pissed, but if anyone can already tell, I dont care about THOSE results.

1. Why are you trying to run throttleless? To me this seems sort of, well, dumb. Pumping losses are not much of a concern at anything less than full throttle (unless I am missing something)

2. Why regulate fueling with throttle position resistance? Would fueling just be easier to modulate with tricking the computers 02 input? (pretty sure the answer is yes, hopefully you can see that)

3. How are you reading EGT's? If you aren't, shame on you?!

4. If you are looking on how to run serious lean burn, why haven't you looked into modifying a stratified charge engine with a more aggressive egr and different injector nozzle sizing with water injection?

5. HCCI? I believe the manufacturers are working on lean burn...

6. Grab a VVLTi engine and control the valves to suit your needs?

7. Emissions are a tricky deal, how important are they in your project?

[Shawn D.]

Originally Posted by Shawn D.

...but are not great for driveability. Such a setup does not compensate for load...

Originally Posted by thecheese429

I wonder if it could be governed so that it works smoothly and can have a changing load (IE, driveable).

Yes, it's called Electronic Fuel Injection!