Cruise Control (with MPG sensitive logic)

[Harpo]

Originally Posted by 8307c4

I do agree, current cruise controls are not as effective as they could be...

The worst part is when the car starts to go uphill first it loses some speed then the cruise OVER reacts, every single unit I have ever used does this, just some are worse than others.

But I'm not really sure how we'd address this issue...
How is the CC supposed to know about an approaching climb?
I think, however, possibly some type of digital level gauge could send 'angle of inclines' information to the CC... This of course would be affected by acceleration and deceleration but then if the CC is active this could be compensated for since our foot isn't doing it.

What I am getting at, is if the car is climbing the CC should at this point merely attempt to maintain speed (most CC's try to get back to the set speed even while still climbing)... Even if it has lost a few mph's it shouldn't try to regain this until things level out some at which point the CC could THEN regain the set speed.

A little smoother on the throttle, basically.

I add a step or two of ACCEL at the bottom of the hill then remove those as I feel the load. That tends to keep the rapid throttle additions (adjusting to instant decels) down to a minimum. I've been using that in the RAM for years to eliminate that overcompensation.

[jomelmaldonado]

Hello everyone, I'm new at this forum. I have a 1998 Suzuki Swift with a 1.3 litter engine and manual. I recently installed an Audiovox Cruise Control CCS-100 and also a Scangauge II. I was thinking, maybe we can fool the cruise control, instead of connecting the Speed Input wire of the CC to the ECM or VSS, we can connect it to a MAP sensor. I know, everyone is going to tell me the MAP generates a 0-5 volts analog signal, but I found that Ford's MAP Sensor generate a pulsating signal depending on the vacuum on the intake manifold. So if we add a Ford MAP sensor to any vacuum line, we take a reference voltage of 5 volts, lets say from TPS or Original MAP sensor, and the output terminal we connect it to the speed input wire of the CC, maybe we can set and lock it by load instead of speed, and this should maintain MPG constant, if the hill is not to long.

Any ideas, please let me know, I've been working the math on the pulse per miles vs. the pulse per vacuum and I think it is possible. If any one is interested, I made calculations and tables in Excel.

[MetroMPG]

Hi jomelmaldonado -

I would think the open source MPGguino platform would be ideally suited to being modified to do exactly what you describe: monitoring fuel consumption and generating a signal to feed the AudioVox cruise unit.

The Ford MAP sensor would be easiest, if it's "plug and play", of course.

[jomelmaldonado]

I am going to try at least to test with the Ford Map Sensor first. If I have any luck, I will be posting the results here.

[MetroMPG]

Sounds good. Please keep us updated - even if it doesn't work out!

[jomelmaldonado]

Hello again. I continue to work on the CC idea, I already found a used Ford Map Sensor, took it out of an Aerostar Van from a Junker. I bench tested it and it is producing an AC output signal. I powered it up with a 5 VDC Fixed Voltage Regulator from Radio Shack, it's the IC 7805 or Radio Shack Cat. # 276-1770. I have to use this because the sensor, like almost all sensors, works with a reference of 5 volts. I didn't like the idea of taking 5 volts from the car wire harness from an existing sensors like the TPS or MAP sensor, so to not strain the internal voltage regulator of my Suzuki Swift's ECM, I am using this external one. It's less than $2.00 and we assure not to put additional loads on the ECM. Tomorrow I am taking this setup to my University to bench test it again, but hooked up to a frequency counter or an oscilloscope to measure the exact frequency it is producing. I will also apply different vacuum levels to make a chart of Vacuum vs. Hz
I will be posting this information and photos probably on Saturday.

Any suggestions or ideas, please let me know.

[jomelmaldonado]

Hello again, as I mentioned, I bench tested the MAP Sensor with a Vacuum Pump and an Oscilloscope. It is working just as described, the nominal frequency and the measured frequency is almost identical. I am including some photos of the measurements with this link of photos. The parameters for the sensor is:

0 inHG = 159 Hz
30 inHG = 80 Hz

Also I included an Excel file with more detailed information on Vacuum Vs. Hz
and MPH Vs. Hz


Any question comments or suggestions, please let me know. I will be mounting it in my car on the next week probably.

[MetroMPG]

Do you know at this point what frequencies the cruise control can work with? Does it care, or is it only monitoring for increase/decrease?

[jomelmaldonado]

Well, at least the cruise I have, an Audiovox Universal CCS-100 can handle a wide range of frequencies since it's supposed to support different voltage levels, Pulse Per Miles and Wave Patterns because different cars have different ways to report the speed. The Auidiovox CCS-100 has an option to choose from 2000, 4000,5000 and 8000 PPM's If you see the Excel file, there is a table I made that converts from MPH to Hz based on the 4 options of PPM's. And in the 8000 PPM setting, the output frequency in Hz from the MAP Sensor falls in between the 8000 PPM setting, actually from about 36-72 MPH.

Remember that with this modification, it will think it's monitoring MPH from the VSS, but actually it will be monitoring Vacuum from the Ford's MAP Sensor. It will only checkl, like always, for any increase or decrease in frequency on that gray wire and it will compensate adjusting the throttle.

[MetroMPG]

I also have the CCS-100 in my car. (Hope yours is more reliable than mine...)

FYI, mine is set up to read only the frequency from the ignition coil, rather than VSS.