Cruise control for constant throttle rather than speed?

[GasSavers_maximilian]

This is a very interesting idea! I gave it a try today using my ScanGauge II to tell me the throttle position. It seemed to work quite well with the TPS at 13, which gives me a level cruise speed of 55. Up steep hills I had to add more, of course. Tempts me to look into an aftermarket cruise control...

[GasSavers_maximilian]

The bungee cord is great, but I was thinking about what a more refined version of that idea would look like. Really, you need a snap action mechanism I think: puts up a lot of resistance right where you want to be, but then if you keep pushing, it eases off so driving at higher throttles doesn't get tiring. Here is a crude picture of one way this could be done (there are many possibilities, some probably much better; this one is good for illustrative purposes). The bottom piece is a cut strip of metal, with a sharp ramp and a shallower one. The small rectangle is the side view of a swinging arm that is spring loaded to bear against the other piece. You can imagine that to get the arm to climb the steep ramp against the force of the spring as you try and slide it sideways would be difficult, but once you'd cleared it it'd get easy (as would be the reverse direction, so it could slow down automatically). In theory you could have more than one position. I doubt it'd be worth doing in practice, but it made for some fun driving time speculation.

[GasSavers_maximilian]

Thinking more practically, for a single position you'd just need a disconnector. Picture two tubes, one inside the other. There'd be a spring loaded, spherical end pin in the inner pipe and a slot in the outer. When that pin comes up against the end of the slot it'll resist, but then once it is pushed in and retracts it won't resist any more. Since a pipe can push as well as pull, releasing the pedal would reset it. Now that's something that could actually be built reasonably. Still not worth it, most likely, but now the concept should leave me alone!

[jcp123]

Originally Posted by Lug_Nut

A locking throttle cable? Motorcyclists have added these devices for decades.

I've got one. I don't use it for cruise control per se, but on long rides, it lets you take your hand off the throttle and stretch out. It's a simple flick of the thumb to disarm it, but in a car I agree it'd be a lot harder...God forbid you get in an emergency situation, I hate to think what might happen if you couldn't get your throttle control...

[Ranana_Zess]

FamiliaGT had mentioned to me the last time we were working on cars that he heard that some of the cruise control parts from a different model I think it was an MX-6.... dont remember what gen were interchangeable. IF thats so, then it might be easier to find all the parts more quickly. My question to everyone else is, "what have you guys heard?" Can some parts from other models be used? Have any of you tried this?

[shatto]

Here is what I discovered with the Dakota;
With the speedometer needle touching the left side of the 65 MPH hash-mark, the truck got better gas mileage than if the speed was set so the needle touched the high side of the hash-mark. This was done for hundreds of thousands of miles and using the cruise control.
The point is, there seems to be a point in the computers algorithm where the optimum performance is. Find it with your vehicle and you'll get the best mileage.

[GasSavers_RoadWarrior]

Yup, Marvin has "sweet spots" like that, I think it's more due to intake and exhaust tuning.... because you can hear a slight difference.

His sweet spots are at 95kph, 105kph and 115kph when "in draft"

Wile-E is difficult, something is twitchy with him at the moment, you have to feel your way into it every time, which takes about half hour of driving so I can't hit them every day.

[GasSavers_maximilian]

Since I'm too wimpy to risk my warranty installing an aftermarket cruise with custom electronics, I was thinking about how to actually build a practical snap action pedal stop. I can lathe the ramped cylinder in the center easily enough and the pin would be spring loaded (flat spring would be very easy, but I can't get that locally). As usual I've botched the scale, but the ends of the outer tube and inner rod would be fixed so pulling them apart would bring the pin into contact with the ramp, creating resistance which would then go away once the ramp was cleared and would only be in one direction. No need for a roller with such low speeds and cyclic rates, although I might want to round the end of the pin a bit. I could add more than one pin if I wanted several resistance positions for various speeds. I think this will work pretty well so now I need to examine how to actually mount it and what size it'd need to be. Getting the resistance right will require a bit of experimentation.

[GasSavers_maximilian]

I was thinking of better ways to design the snap action and while I came up with a few, I decided that I don't like the entire paradigm. Really I want a system I can lock anywhere and that, like a cruise control, sets the minimum throttle, allowing me to go higher than that without disengaging it to climb hills. I have a rough design in mind, but want to sleep on it a bit before drawing it up. While it could be manually operated, I think I prefer a solenoid lock so that various automatic disengagement systems could be used. I also like the idea of a safety kill switch just in case, which would be harder to do mechanically.

[dkjones96]

GM has done similar stuff on their throttle by wire cars. They put springs in there that get progressively much stiffer over the entire travel of the pedal.