Vacuum Automixer project

what about for hybrid driving?

More to come on that… currently not set up for it.

With the complexity of today’s trucks, it oddly looks stock under the hood. Time to take the Dakota to a mechanic to ask him what those parts are. :grinning:

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Nice job @Chris. When I finally find a truck, this will be going in the build.
BBB

Looks great Chris! Take my money. I would definitely buy that if it was sitting on the shelf.
I had to chuckle when you noticed the water heater.

Great work Chris! Very impressive… Thanks.

Cold startup with the new system.

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Very sweet Chris. thanks for the video.
So the new valves are just to shut off the woodgas for gasoline driving?

Yes. In normal operation they stay open all the time.

Super nice job Chris! I noticed that your AF gauge was in the green (rich) after start up. Mine runs best on the lean side. Is this adjustable in any way? Yours seems to run very good this way but does it lean out once it warms up? I have to do a little more studying on how that diaphragm knows where to set the butterfly first shot in the box. Is there an initial linkage adjustment that puts it at about 50/50 instead of 60/40 or whatever?

At 9:50 you can see when I put it in gear, the reading goes lean and stays put. I’m not sure what causes that. Could be the initial “pushed” gas was a bit richer than normal.

At any rate, it’s never gone overly rich, just enough the meter shows it. Anytime under load it stays right on target, occasionally it will go a tad rich when you romp the throttle. I’ll have to make (yet another) video showing the AFR as I drive around town.

Nope, that’s the thing… there’s no initial adjustment because the full range of travel is under the control of the diapghram. No matter where you set it, it will rebalance itself.

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Don, if you go back to post 132 where max has the diagram, you see the separate bellows for cranking mix. the next couple posts explain it’s operation.
Since the main diaphragm is only controlling the pressure of the gas and air to be equal, any adjustment of the actual fuel air ratio would have to be done with the dual throttle plates if I am understanding this correctly.

HI Chris saenz,Can the 60 40 adjustment be changed a little one way or the other,with longer hoses on one side,or the other,Glad you got it working,looks like nice add on.THANKS

Hi Kevin,

Nope, the pressure balance has to be 50/50, that’s the only way it can work… The membrane will constantly move until it finds that equilibrium.

Changing the hose lengths won’t really matter; adding a valve in the air sensing line will dampen the responsiveness of the valve to prevent overshooting. But eventually it will still find that 50/50 equilibrium.

Now, what you could do is add an additional manual valve on the air line between the diaphragm and the throttle. This would let you restrict the air further and richen the final mixture some more. This will compensate for weak gas, or unsymmetrical air/gas lines.

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Thanks,sounds like it should work good like it is.

I keep thinking that the gas valve is always wide open like it was before the auto mixer and that the membrane only adjusted the air valve like I have to do manually now. That is where I was wrong. the membrane adjusts both gas and air! It took a while but I think I finally got it. :grin:

Close… The membrane itself only controls the air. However we are throttling both gas and air. This is why at crank up we get a tiny measured equal amount of each - not from the diaphragm but from the throttle itself. As we move to wide open throttle, the gas plumbing becomes the restriction and the air flap is auto-adjusted to match.

I feel like the more I explain it the more complicated it gets… Sorry guys.

WOW that is really amazing, and hard to wrap my head around! Great demo, great job, Chris.

Made a trip around town tonight, and kept the camera fixed on the AFR gauge. The idea here is showing how the automixer responds to throttling up and down, long pulls, sudden stops, and idling. I did some of all of it in the video - even managed to stall it once, goofing around. But if you drive sensibly, it’s remarkably stable. Even a bit boring… :slight_smile:

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Fascinating!
How does the Lambda meter behave on gasoline on the very same route, equally driven?

Max