Cruise Control (with MPG sensitive logic)

[jomelmaldonado]

Well, I was planning on only using the RPM, but I found the VSS wire, taped it near the ECM. It was a little bit confusing because I could only find the Geo Metro diagram, and mine is a Suzuki Swift, it changed the color code for the wires, but it turned out OK. You can set your CCS-100 to read VSS with the DIP Switch settings. I will be posting the progress of this experiment on the week.

[trikkonceptz]

While the idea of cruise control maintaining a constant MPG is a worthwhile cause, it will really create problems for us. I am sure with the great minds we have here we can develop and test a functioning bench test model, but here are my concerns.

I use CC everyday on my commute, in fact it is the only way I can maintain the high mileage averages I get. This gives me time to monitor the scangauge reading during my commute. I notice that my instant MPG fluctuate continuously throughout a range of about 7mpg due to traffic, wind conditions and the most obvious road elevation. Those small changes in MPG's would crash any computer trying to determine how to react so quickly to those changes.

Instead, I feel the CC should have a P&G mode utilizing they latest technology in order to sense distance ahead of it in order to avoid accidents while doing P&G or even simple locked CC. Including a logic for hill climbing and simulated EOC would be icing on the cake, but it would take one of us on the inside to convince auto manufacturers to pay so much attention to something percieved to only be used on long trips to Wally World.

[jomelmaldonado]

Hello again, I mounted it in my car today and it is working fine, after ironing out a kink. I knew that it was supposed to be set to PPM = (8000), also the Speed Signal was set to (VSS or Magnets); so I did that before making the first test run. The only problem I had was that when I pressed the set button, it over reacted and opened the throttle to much, immediately after, it canceled out. I tried a few times at different speeds and loads, but it kept doing the same. Then I changed the DIP Switch setting to Sensitivity (LOW) and it worked fine.

I tested it in flat roads and grade roads and it maintains a constant engine load. In the ScanGauge II, it was displaying very close to 52 MPG, it went up and down about 3 MPG. Also I was monitoring the TPS and Load with SGII and it wasn't jumping up and down erratically, instead, it was fairly smooth. I consider this very good for what it's calculations are doing and at the speed it has to perform the calculations and react to throttle position to compensate.

I am going to further test the car and will be posting my results. Also I will be making a block diagram and taking some more photos. I will put it in my album. I also included another Excel file that describes the theory of operation.

The important thing here is that instead of setting a Speed, know we can set MPG's to maintain it constant.

[NeilBlanchard]

Good stuff! I'm looking forward to your progress.

[jomelmaldonado]

Hello, just wanted to comment that the Cruise Control is working fine and it is maintaining a constant engine load. I am including an additional picture of DIP Switch Setting so everyone could have a better idea of how to set up there CCS-100.

[jomelmaldonado]

Hello again, just wanted to keep up to date with the experiment. I added a block diagram for those who want to try to modify there CCS-100 or similar. Also I would like to comment that my mixed city driving went up from about 41.8 MPG to 47.5 MPG with this modification. It's posted in my fuel log.

[NeilBlanchard]

Hi,

That is a great result! Now, if we can get the car makers to implement this on the stock "cruise" controls...

[jomelmaldonado]

Well, probably not all drivers will be willing to sacrifice MPH to gain MPG, but we hypermillers are willing to give the extra miles, well in this case, the extra MPG to reduce fuel consumption. Any way, it is possible to do it, so perhaps some company will think about it and put an option in the OEM cruise control for steady MPH or steady MPG mode. That's the next mod I am going to do to it.

[wagonman76]

This is cool. One could possibly even modify a stock cruise control to work like this.

[NeilBlanchard]

Hi,

I think it would be best if the MPG could be the main criteria, but below a certain speed (say 5mph less than where it is set -- this speed drop should be programmable) then the throttle could be increased to keep going above the minimum speed.

In other words, If you set the control while getting 60mpg @ 55mph, the control would try to hold the MPG (constant throttle position?) as high as possible (or even increase it, if that starts to happen), but if the speed drops below 50mph, then the throttle would be increased just enough to keep the speed above 50mph.

If you are going downhill, and you start gaining speed, the opposite might help: let the speed go up to 60mph (the speed increase should be programmable, too), and then back off the throttle to get better MPG, and then only increase the throttle back to original setting when the speed drops back below 60mph.

So, dual (triple?) curves would make this sort of control ideal, IMO.