Gas mileage training aid
 

I saw a little device in a video recently that teaches the driver how to save fuel. It's a little box with LEDs that mounts on the dash, and the LEDs light up red if the driver accelerates or decelerates too quickly, thus teaching the driver how to drive more efficiently. I've searched and searched and can't find this thing anywhere, has anyone seen this thing? I would like to suggest this to people I know who are pretty much clueless as to how to drive efficiently, I think it would prove very helpful.

I've never seen it, but seems like it would be easy enough to make.

How in the world could it know what the optimal acceleration rate is for a specific car? It might do more harm than good.

Unless it works similar to a vacuum gauge.

I think I saw it through a link someone posted recently.

I bet for a GPS receiver hardcoded with generic values. The GPS receiver gives not only the position, but also the speed and the acceleration.

A few weeks to design, a few dollars to build and you can sell 50. Will pay for itself rather quickly even if people save only 10%.

Far less powerful than a SG, but will be enough to a lot of people. With a SG you have to analyze numbers in real-time to know what you have to change... People do prefer something telling them what to do, or what they are doing bad.

Even if you only say people when they are accelerating too quickly or driving too fast, this is enough because that box is looking at it all the time. It's still hard to me to have always good accelerations and good speed.

People will not become hypermilers, but will meet EPA and will be happy to save money.

Denis.

you could make that for 15 dollars worth of parts on a circuit board 1" x 1". Analog output 1-axis accelerometer, 2-channel comparitor. Set the light to turn on when the accelerometer outputs a certain level on accel and decel (one comparitor each), and you're done.

If doesn't have to be "optimal", it just has to be a help for people that care less than your typical EM reader.

If P&G is a good FE technic then what is so wrong with fast acceleration? Isn't the Pulse in P&G just fast acceleration?

No, I don't htink so. Correct me if i'm wrong as I am new here, but i believe that in P&G, the time taken the accelerate should be the same as the time taken to coast. A hard accel is just a huge fuel dump with little efficiency.

You want acceleration is a certain range - too low is as bad as too high. "slower the better acceleration" is a myth.

I agree that an accelerometer would be useful input for maintaining optimal acceleration rates.

I suggest that car manufacturers:

1) allow the cruise control "resume" button to work from a standing stop.
2) tweak the resume to maintain optimal acceleration

I understand this, but I thought a big part of the FE gain in P&G was the fact that the motor is running at its peak efficiency, with regard to power generated vs. fuel consumed, at a 2/3 to 3/4 throttle opening (pulse mode).

Slow accel and decel never operates the motor in its peak power/fuel efficiency range.

Having said all this, I do indeed accel and decel gradually and I know I get better mileage for it. I guess my main question is, how is it that P&G can be so FE effective since it goes so contrary to slow accel/decel ?

Put another way, why wouldn't it be best of all to use a 'slow accel then glide' since slow accel is better than hard accel?