Test: Alternator vs. no alternator = 10% MPG gain @ 70 km/h

[hotrodfeguy]

Exactly and combine it with a solar panel I think we could come even closer.

[RobertSmalls]

I've read somewhere on this forum that Hondas have been doing intelligent alternator control since at least the 1980's. Your car may be one step ahead of you.

Also, if you have a hybrid, you can disable the DC/DC converter and deep-cycle the 12V battery. Grid charge at home to save gas. The savings will be smaller, though, because the hybrid spends very little gas on 12V charging anyway.

[thecheese429]

Why not just put a relay on the field control circuit? I have been thinking of disabling accessory belt items, and think that just "un-field" the alternator would prove satisfactory. I put a light bulb on the EGR valve to monitor when exactly it is engaged. My discovery was that it is active when the engine is cold or not under (some) load. When warm, it would de-activate as soon as I put a little more pressure on the pedal.

Why I mention that is that it could possibly be a way to make the alternator only come on during low-load times (when EGR is active)

[thecheese429]

Originally Posted by Newton

i'll be sure to keep you all posted, i'll start a thread probably when i do it seeing as how there's a bit of wiring needing to be done so that when the temperature gradient is gone they don't pull power from the battery and become heat pumps (one side gets hot the other side gets cold, they're kinda inefficient so that keeps them from being used for heating/air conditioning) the two i have on the way (probably another week or two) are 20A @ 12v each so if i wire them in parallel then i can get 40A @ 12v. The replacement alternator for my geo will produce 50A and i doubt that it's producing that constantly so i imagine at 40A i'll have some extra juice to use for the rest of the car. On paper this should work, only issues i have to tackle first is that they cannot exceed 68C (154F) so i'm going to go pick up a laser thermometer, i might have to bolt a plate above the engine at the correct height that it will get close to but won't exceed 68C

I have played with these. The peltier effect induces a flow of heat energy with a flow of electrons. The opposite effect, what is discussed here, is called the seebeck effect. IE, a current is induced by a flow of heat energy.

A novel concept, but I must say that efficiency is far from ideal. I had some 40w (maybe?) cells, and with a heat sink on top, and a candle underneath, I could hardly get enough power to spin a 5v computer fan. I think I measured the output at about 2V (which was high, usually much lower) and not much current to play with.

In my readings of the Seebeck effect, I seem to recall that high wattage peltier cells were actually the worst for the Seebeck effect. Somehow or another a low wattage cell would be more efficient for Seebeck. I could be wrong, though.

[Piwoslaw]

Originally Posted by thecheese429

Why not just put a relay on the field control circuit? I have been thinking of disabling accessory belt items, and think that just "un-field" the alternator would prove satisfactory. I put a light bulb on the EGR valve to monitor when exactly it is engaged. My discovery was that it is active when the engine is cold or not under (some) load. When warm, it would de-activate as soon as I put a little more pressure on the pedal.

Why I mention that is that it could possibly be a way to make the alternator only come on during low-load times (when EGR is active)

This might be a good idea, though engines may differ among themselves as far as EGR is concerned, exactly when EGR is on/off should be tested individually. Only you want the alternator on during high load, not low, if you are doing it for fuel economy. The reason is that the IC engine is more efficient at higher load, so you will use slightly less fuel to produce the same amount of electricity.
Of course, if you are seeking more power, then it should be as you proposed.

What kind of light did you hook up to the EGR? Any idea as to the current there? I may try this to check when my EGR is on/off.

[thecheese429]

Originally Posted by Piwoslaw

What kind of light did you hook up to the EGR? Any idea as to the current there? I may try this to check when my EGR is on/off.

The vacuum valve on my truck has just 2 wires controlling it. The specific bulb that I used was a T3-1/4, just put in parallel with the vacuum solenoid. It works because my system is just on/off, as far as I am aware.

I don't know how well it would work on a newer car, with % mix control and what not.

[pounsfos]

wow this is some heavy stuff, i might have to get into this, my cars 28 years old so who knows whats going on with the alternator there,

oh and which would be better internally controlled or externally controlled alternators
(mines externally controlled)

[MetroMPG]

Alternator with an external voltage regulator would be easier to hack.

[Nerys]

hey I wonder about the 1 wire alernator problem. part of the problem is if you cut the wire while its "charging" well nasty things can happen to the alternator (out of control field charge etc..)

so I wonder. could you cut the wire with a relay and then connect a BATTERY to the alternator? ie a 15v source to "trick" the alternator into seeing "full charge" and shutting itself off before you cut the wire ?? once you have cut the wire it would be safe at that point.

[vacationtime247]

Seen the graph, informative. Best way to run an alternator less system is to decrease the draw on the battery to prevent discharge. Daytime driving would be ideal. All the vehicle needs is fuel and ignition to run with the most basic gas engine system. Seems with newer vehicles there are so many more electrically reliant systems. Takes electricity to run an ECU for the fuel pump and ignition. Wonder what the MPG difference is between a mechanically driven system vs an electrically dependent? Ya know, old school (cam driven fuel pump, carb, cam driven distributor points condensor) vs new school (fuel injection, electric fuel pump, distributorless ignition, ecu, TPS, CPS, etc)
Find and eliminate any electrical draw that isn't essential. Should extend the distance driven and life of the battery. This may include the dash display, radio, providing the least amount of draw but maximum flame front for the ignition. Wonder if a lower coil output unit, low draw plug wires, changing the spark plugs and gap would have much effect? Using a low draw fuel pump and the time it takes to prime the system. What's the least it takes to run the fuel pump and prime the injectors?
But, you seem to know what you're doing and may have already considered these factors.
VT247

Originally Posted by MetroMPG

Bearleener: I did a more accurate audit of the electrical demands of my car, and it's much lower than I originall guesstimated (based on someone else's Honda Civic figures).

FYI the results are here: Tested: power draw of Geo Metro accessories & systems (volts, current/amps, watts)