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EcoModding Lurker
Join Date: Jul 2010
Location: Mojave Desert, CA
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Sorry to chime in so late on this . . .
I just found this thread while doing a Google search looking for a type of wheel balancer that uses balls runing in a circular track, and the search picked up your recirculating ball flow meter.
I used to have a full sized van that used a Zemco computer which worked quite well. I know this computer has been mentioned in the thread, along with a recirculating ball flow meter. I have not read every post in this thread, so forgive me if information is redundant.
I am just offering a few facts about my setup, that might be useful in your topic.
First thing is, my flow sensor was not a recirculating ball. The flow sensor on mine, consisted of a paddle wheel enclosed in clear plastic with and inlet and outlet. There was an underdriven electric filament lamp on one side, and a photo resister on the other side, to count the blades of the paddle wheel as it passed the light.
In such a design, the volume of the flow chamber could be designed to affect the speed of the wheel, and the clearance in the chamber where the wheel rotated, would affect speed also. Number of blades could be altered to change the number of pulses, but the number of pulses is not that important as circuitry can be designed to multply or divide the physical pulses to an electrical output as needed.
Calibration was handled by the cumputer. There where 4 magnets that where atached to the driveshaft with a combination of safety wire and double stick tape. That worked fine, by the way. The magnets rotate on with the driveshaft, near a coil mounted on a bracket to the chassis. That provided pulses to the computer to count miles driven, which of course, was again calibrated by the computer.
Here is how the calibration worked. You filled up the fuel tank, and drove the vehicle, and at your next fill, you wrote down the gallons to refuel. You did this several times, and afterward, you inputed (through a numeric keypad) how much fuel was totalled on all of your refills. The computer then references its internal memory of how may time the light beam was proken in the fuel flow paddle whel meter. This let the computer know, how much fuel is passed for each break in the light beam.
By using the several tankfull averageing method, it got a good way to compensate for differnat volume of fuel as it changed with temperature.
To calibrate the disance aspect, you simply found some freeway mileage markers (now yo could use a GPS) and drove the 3 or 5 miles or whatever, and told the computer how far you just drove. Again, referring to it's internal count of pulses from the driveshaft, it now knew how far the vehicle went for each pusle.
The distance, was a very accurate method. The fuel measurement had a small problem. On my van, fuel flowed from the tank to the fuel pump, and the flow meter was in between the two. However, there was also a return line to the fuel tank, from the fuel pump. That fuel was never measured. On of the purposed of that return line, was to keep new fuel flowing through the lines, to keep the lines cool and prevent vapor lock. Zemcos remedy for this return flow, was to give you a restrictor orifice for the return line, which tended to make the return flow more metered an predictible, so that the averaging system was essentiall measuring a varying flue flow at the paddle will, while assuming a more or less steady rate of return to the tank,
It actually worked pretty well, except that the car did occasionally suffer from vapor lock. There were different sizes of restrictors, and the more restrictive, the more accurate the fuel use estimate were, and the more prone to vapor lock, so in the end, accuracy was compromised.
The right way to do it, would have been to have two fuel flow meters, on on the supply, and one on the return, and subract the pusle count of one from the other, but that would have been more expensive.
I really liked that driving computer, it had 44 funtions, anything you can think of that involved time, distance, speed, fuel useage etc, whether instantaeous or average, curent or to empty or to destination. It also had cruis control, you inputed 60 mph at the keyboard, and it would accelerate to 60. All functions we available in english or metric, if I had any carbureted vehicles, I would love to have oe. The only function that I though is missed, was an input for the cost of fuel, so you could see cost per mile, cost per hour, cost to destination, cost on trip etc.
Good luck on your quests, hope something there was instructive.
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