Cruise Control (with MPG sensitive logic)

[guitarterry]

I was wondering if there was a way to set up a cruise control but instead of speed, You use mpg. of course you would need a min and max speed. Since I got my scangauge I have gotten great MPG by just tring to keep a certain mpg. Sorry i cant use other driving techniques as i have an auto and crowded highways. but a 36 to 41 boost is good for a start.

[MetroMPG]

A smart cruise control would be a fantastic feature for many, and would save a lot of fuel. RH77 modified his so that it could only pull a certain amount of extra throttle when encountering hills, but nobody has done exactly what you're talking about.

FYI: What features on your ULTIMATE fuel economy instrumentation?

I bet there are lots of other small things you could do to improve MPG at either end of your drive on the crowded highway.

Watch for a new feature on the site later this week: 100+ efficient driving tips for all kinds of situations.

[guitarterry]

As you have stated, the biggest improvement u can do is driving mods. if you are not going to do any P&G driving then a mpg cruize control would be like the ultimate invention. Then any car mods you do will either make you go faster or allow an increase in ur mpg setting. This seems so amazing and also easy that why isnt anybody doing it.

[jpgmtech]

You have given me an idea! This may be possible to do in a typical ECM, as the software already governs cruise control...

I'm going to see if I can modify this parameter in the ECM...

[guitarterry]

thats what i wanted to hear, it seems simple easy and highly productive.

[JohnnyGrey]

What happens when you hit a hill and can't maintain 40mpg? Your engine shuts down?

How about cutting the power to the cruise control motor once it's engaged? That way you can freeze a certain throttle position.

[metroschultz]

If you hack the cruise for MPG it may be easier on the input end to use TPS voltage instead of VSS volts.
This would allow constant throttle instead of constant speed.
Let me know how you do.
I am not a good hack but I can follow instructions.
Thanx,
S.

[jpgmtech]

I'll look into this for different cruise control systems when I get a chance. Right now I'm looking for software solutions.

Theoretically: Vacuum-controlled cruise, set cruise to specific throttle position and then isolate the vacuum source solenoid and electrically cut off the dump solenoid to maintain specific TP. Tap the brake going over a hill to release cruise, de-isolate cruise vacuum valves, then hit reset at bottom of hill, re-isolate...

[guitarterry]

Originally Posted by JohnnyGrey

What happens when you hit a hill and can't maintain 40mpg? Your engine shuts down?

How about cutting the power to the cruise control motor once it's engaged? That way you can freeze a certain throttle position.

If you have to do a total system you would have a minimum and maximum speed. if not i would supose you would know you are going to slow. But that is the whole purpose IS to slow up going up hill. Do you have a scangauge. if not you wouldnt understand what maintaining a mpg setting details.

[LostCause]

I don't think you'll be able to maintain 40mpg going up any long, steeply graded hill...going slow works to a point.

If it is constant throttle you seek, why not just hook the throttle servo to a potentiometer.

I'd imagine using a cruise control based on MPG might pose some dangerous situations. A car will shift its speed greatly as it is loaded differently throughout a drive. I can't imagine that driving 65mph, slowing to 40mph, and speeding up again to 60mph would be particularly safe in any form of traffic. If you are completely isolated, then I suppose it might be useful, but not as a daily use item.

I'm interested in watching any developments, though.

- Lostcause