Automatic alternator cut out/regen braking

[oldbeaver]

Originally Posted by drmiller100

hook a switch to the throttle. When throttle is closed, field windings are energized.

with the same switch, turn off the power to the fuel injectors.

Your first sentence sounds good to me: alternator will be ON every time the car is down a slope or going to stop.

However, it will be on always on accelerating.

The second sentence I do not understand: turn off the power to the fuel injectors with the same switch.... while coasting .... hmmm ok, that makes maximum fuel saving. I think this is already programmed so in modern diesels, I don´t know about gasoline engines.

I think yr ideas are good because they are logical and simple. Good for starting. However, I would like to have more power when climbing, and more fuel yield when traveling, turning off the alternator, when possible. Arduino can help.

Oldbeaver

[Josh8loop]

This is an interesting concept. I believe the goal is to reduce resistive losses in the rotor wiring, and also to reduce eddy current losses. With more modern(2000 plus) vehicles, I wonder how the ECU would handle an open circuit to the field of the alternator? My guess is that it would throw codes for sure.

I like this idea, and coupled with replacing the internal diodes with low forward voltage drop schottkey diodes(perhaps saving as much as 5 watts per diode at certain power outputs), and coating the rotor with epoxy to reduce windage losses(while making sure rotor overheat doesn't become an issue) and you really have something here. If I remember correctly I energized an alternator rotor once, and it used about 36 watts steady state-I realize this will most likely be reduced as the voltage regulator does it's thing, but still thats not too bad!


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[Josh8loop]

Fellas,

I am now pursuing the creation of a "Hybrid" alternator for my 2002 VW Jetta TDI. My objectives are to modify the alternator rotor with some properly placed permanent magnets to help partially reduce the energy required from the rotor coil to create the proper magnetic field density. This will be more of a magnetic rotor "Bias" so to speak. Normal alternators full fielded will use 3-4 amps, so if I can reduce that a bit to say 1-2 amps that will be a savings in itself. The other objective would be to coat the newly modified rotor in epoxy resin to make a nice smooth shape-this should cut down on windage losses a bit(will increase rotor mass though). Since we now have a magnetic bias the rotor no longer needs so much current to maintain rotor magnetization so the resistive rotor coil losses will be reduced and rotor temps should be acceptable with the resin coating. The final change I would like to incorporate into this project is to bring the 3-phase AC out closer to the battery location to be rectified with some low forward voltage drop schottkey diodes. The schottkey diodes will reduce losses in the diodes to some extent, and transmitting the battery electrical energy as AC current directly to where it will be rectified could further reduce resistive losses in electrical connection between the alternator and battery. Synchronous rectification I'm told can reduce rectification losses even further, but at this point I'm unsure how to acheive that.

I envision the use of a Click PLC control topology with inputs from brake pedal, accelerator pedal, battery voltage, charge current and others. This will allow simple and extremely flexible alternator control logic schemes that can be changed at will as things progress. A local friend has donated an alternator as a guinea pig for the transformation. I hope to modify it, test it on a test stand at a local auto parts store, and install it into the car eventually.

[kurzer]

i read in this forum about the intelligent alternator, honda is using since at least 20 years.
so i found out, it cuts the voltage to 12,5v at some times while driving. thats the best plan for me. in fakt i think, this is enough most of the time. a honda mechanic told me, the batteries of these old civics lasted even longer, than usualy. an other good to have point.

the alternators have an aditional wire, called FR (fuel reduction i guess) this is driven by the PGM ECU. look at the pic...

i guess this wire is conected to ground or not in case of 12,5v and 14v, but this is only a guess, nobody could told me so far. so if u have a civic or an alternator, maybe u can find out for us.

[Josh8loop]

Originally Posted by kurzer

i read in this forum about the intelligent alternator, honda is using since at least 20 years.
so i found out, it cuts the voltage to 12,5v at some times while driving. thats the best plan for me. in fakt i think, this is enough most of the time. a honda mechanic told me, the batteries of these old civics lasted even longer, than usualy. an other good to have point.

the alternators have an aditional wire, called FR (fuel reduction i guess) this is driven by the PGM ECU. look at the pic...

i guess this wire is conected to ground or not in case of 12,5v and 14v, but this is only a guess, nobody could told me so far. so if u have a civic or an alternator, maybe u can find out for us.

or "Field" reduction?



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