# Use existing ICE as generator



## Moffer (Jan 28, 2017)

So pretty much it's like a diesel electric locomotive, only it's gas electric automobile.


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## Duncan (Dec 8, 2008)

Hi Moffer

Why would you want to do that?
Every time you convert energy the gods of engineering take a cut

Chemical to mechanical -
Mechanical to wheels -

verses
Chemical to mechanical -
mechanical to electrical
electrical to mechanical
Mechanical to wheels 

The generator and motor can be quite efficient - but even 90% x 2 = 19% additional losses

Trains accept that hit in exchange for eliminating the problem of a gearbox and lots of driven wheels

What are you trying to achieve?


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## onegreenev (May 18, 2012)

Simplest solution is to buy a Volt. Put a hitch and tow a trailer if you need to haul something.


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## Moffer (Jan 28, 2017)

Not trying to achieve anything special than just simplifying the drivetrain and learning while I piece it together. I know it's not the most efficient but it's just something different and fun


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## Sunking (Aug 10, 2009)

In all my years here this has got to be the dumbest thing I have ran across.


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## dcb (Dec 5, 2009)

start small moffer, you are grossly underestimating the engineering effort and learning curve here, and there is really no payoff.


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## Sunking (Aug 10, 2009)

dcb said:


> start small moffer, you are grossly underestimating the engineering effort and learning curve here, and there is really no payoff.


The payoff is the same chance of bringing back 8-Track Tapes and Buggy Whips.


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## Moffer (Jan 28, 2017)

Huh... Thought y'all would be helpful and understanding. Instead it's just disheartening and unconstructive insults. I'm trying to do this just for fun. No profitable reasoning for it. Guess I'll look elsewhere for help.


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## dcb (Dec 5, 2009)

Moffer said:


> Huh... Thought y'all would be helpful and understanding. Instead it's just disheartening and unconstructive insults. I'm trying to do this just for fun. No profitable reasoning for it. Guess I'll look elsewhere for help.


Oh shut up. Either learn from what people have said, have a look around, or don't. But don't propose a glorified slop-o-matic electric transmission on a gas guzzler on a diyELECTRICcar forum then act butthurt when you find out it is an awful idea.


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## Moffer (Jan 28, 2017)

Not butthurt... Just surprised at the internet tough guys, like yourself, that offer no help but only bash. It's on the same level as the 9 yr old saying he's gonna bang your mom on a videogame. I expected mature diy'ers to help. I know my idea doesn't make sense. Just like a solar powered flashlight. It's just a project that's for stupid fun...


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## dcb (Dec 5, 2009)

It is a dumb idea, and not worth anyones time, what are you whining about now? That we don't encourage a dumb idea?!?

Like I said, you are grossly underestimating the engineering and learning curve efforts here. Stop complaining and start learning, or leave like you said you would.

Lets start with the basics, 
what is your budget?
What is your estimated vehicle weight (loaded w/passengers)
what is your coefficient of drag
what is your rolling resistance
what top speed do you want
how steep an incline do you need to climb, and how fast?

From that you can at least figure out how much power you need at the rear wheels. And you can figure out torque/rpm curves and look into gearing options.

But what you are calling "fun", is you actually learning how to do the part you are completely ignoring. 

If you ask specific intelligent questions, they are more likely to get answered. If you just focus on the traction motor for starters, then we have something in common, and really until you get your head around that there is no reason to talk about an ICE and a generator because you won't understand what people are saying anyway.


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## galderdi (Nov 17, 2015)

Sunking said:


> The payoff is the same chance of bringing back 8-Track Tapes and Buggy Whips.


 8-Track Tapes??? Awesome suggestion I'll buy 10.


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## Moffer (Jan 28, 2017)

My ignorance prevents me from asking the intelligent questions which is why I asked such a broad question. Your last post is exactly where I'm trying to get. The conversion is on a 2005 Subaru Forester X. Budget is as I go but not wanting to go over $10k. Weight is about 3100 pounds without passengers or added weight of EV parts. Drag is around 0.405. In my ignorant speculation, I was thinking about an ac-51 to power just the rear wheels. My thought was getting rid of the rear axle and putting the ac-51 (with the shaft coming out both sides) in its place. Possibly going into the spare tire well.


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## Moffer (Jan 28, 2017)

How do I find out rolling resistance? Top speed in looking for 70mph. Inclines are minimal being near Chicago.


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## dcb (Dec 5, 2009)

you might be able to reverse engineer it a bit, i.e. if your forester is working.

google for a dynamometer graph for your engine, google for cda values, start looking for the missing pieces of the puzzle. Look for a list of the gear ratios in the transmission and rearend so you can sort out torque and rpm (is it manual)?

look for a top speed reference, figure out the rpm, relate that back to the torque (dynamometer) through the gearing changes at the engine, determine the power at that rpm, and you can use that as a rough basis for cda. I don't have the exact formula, there is some fudge involved anyway, you will want to google that too. 

Or if you can find a bsfc chart and can measure your fuel consumption accurately, you can travel at different speeds and get a good idea of the power required.

Or you can google rolldown tests, where you carefully coast down from higher speed in neutral several times and use the rate of decel to figure it out. similiar for rolling resistance, see how much force it takes to keep the car rolling in neutral at 1mph or so on level ground.


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## onegreenev (May 18, 2012)

Moffer said:


> My ignorance prevents me from asking the intelligent questions which is why I asked such a broad question. Your last post is exactly where I'm trying to get. The conversion is on a 2005 Subaru Forester X. Budget is as I go but not wanting to go over $10k. Weight is about 3100 pounds without passengers or added weight of EV parts. Drag is around 0.405. In my ignorant speculation, I was thinking about an ac-51 to power just the rear wheels. My thought was getting rid of the rear axle and putting the ac-51 (with the shaft coming out both sides) in its place. Possibly going into the spare tire well.


You will want to run the motor through the differential. You don't want the shaft of the motor being the shaft of the wheel. You do need some sort of differential.


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## Moffer (Jan 28, 2017)

Forester is auto. I'll be doing more googling, then, and get back on here with what I find. Why is a diff needed instead of the AC motor driving the wheels directly?


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## Matej (Dec 4, 2015)

What you are describing is very similar to what I was considering doing just a month ago with my diesel car. Mainly because I hate how fragile and complicated car transmissions are, so I wanted to replace the transmission with an electric motor. The manual transmission for my car is also quite a bit rare, and I could get a nice sum of money for it while it is still in good condition. Not to mention I thought that I could have the driving characteristics of an electric car, with a much better range than the average EV conversion, and without the long charge times.

You may see my thread here:
http://www.diyelectriccar.com/forum...l-electric-series-hybrid-dreaming-179962.html

I was considering two ways of implementing it. One would be to use one of the original diesel engines that fit in the car, and attaching a skinny Honda IMA motor to it as a generator. Then there would still be enough room to hide the electric motor in the transmission tunnel. This method would appear totally stock under the hood, which I thought would be very neat. No one would suspect that the car is actually powered by an electric motor. The other way was to put the ICE in the trunk, using a larger generator, and going wild with the traction motor setup, such as using dual motors.

In the end I decided against it. After having tinkered with cars on and off since I was a teen, I am done with dirty oily greasy leaky combustion engines, along with exhausts, gas tanks, turbos, and all the other junk that accompanies them. I remembered that the main appeal and the original reason why I became interested in EV conversions is how clean they are to work on and their silent operation.


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## Moffer (Jan 28, 2017)

Good info! Thanks!


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## jhuebner (Apr 30, 2010)

Not that I like projects including an ICE, but here's my minimally invasive suggestion:


ICE in front driving front wheels, completely stock
AC motor driving rear diff
Small battery with high power density
4 drive modes


ICE only, Electric system off
Electric only, ICE off, transmission in neutral
Both driving for all wheel drive
ICE driving front wheels, AC motor regenning power into the battery from rear wheels
Just need to multiplex the throttle pedal and you don't need to go through the trouble and weight of adding an extra generator.
Of course drive mode 4 gives away some efficiency but any project including an ICE is inefficient.


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## Moffer (Jan 28, 2017)

That's one of the setups I was thinking about. Would it be efficient to bolt a generator head to the ICE to charge the batteries as well? Like to run in electric mode and have the ICE run at an optimal rpm as a generator


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## dcb (Dec 5, 2009)

charging the batteries with gasoline is the least efficient use of gasoline.

re-read duncans post, all these conversions from chemical to heat to mechanical to electrical to chemical to electrical to mechanical etc etc add up quickly.


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## Moffer (Jan 28, 2017)

Why do freight trains use diesel electric instead of just using a large diesel or large battery bank? I'm sure there's a good reason, I'm just curious. I've read how even highly efficient electric systems still have a 10% effiency loss. Add that to the loss you'd get going from ICE to generator, generator to battery, battery to electric motor, electric motor to wheels... Looking into what Duncan said is making even more sense and I'm seeing the major flaws in my original idea. I was originally just perturbed and being made fun of when I'm new to this and trying to figure it out. Is there a more efficient way to generate electricity other than just plugging in a battery bank to your home outlet?


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## Moffer (Jan 28, 2017)

And if charging batteries using gasoline is the last efficient use of gasoline, does that mean a hybrid is more efficient than an EV with a gasoline range extender?


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## dcb (Dec 5, 2009)

Moffer said:


> Why do freight trains use diesel electric instead of just using a large diesel or large battery bank?





Duncan said:


> Trains accept that hit in exchange for eliminating the problem of a gearbox and lots of driven wheels


the engine drives an alternator, which makes it relatively simple to control, and makes it much easier to drive all the wheels, and a lot more reliable as well. Gears and bearings and driveshafts everywhere would be a maintenance nightmare, especially with all the miles trains run and the loads they carry.


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## jhuebner (Apr 30, 2010)

Concerning diesel-electric trains: they emerged from the observation, that a pure diesel train idles most of the time. A large engine is needed to accelerate the mass of the train. After acceleration because of the very low friction of trains as opposed to cars the motor idles.
Diesel electric combined with a relatively small battery bank allows strong downsizing of the diesel engine and thus lowering the idle losses. In addition it allows removal of clutches and other gear specific to ICEs.
Extra generator: if you stick with the typical car engine (100kW or something, maybe [email protected]) and a small (say 10kWh) battery pack, you'd have to charge the battery with something close to 5C to run the engine efficiently. That will wear it pretty quickly (as does fast charging). It seems unpractical/uneconomical/happy engineering to me but you can do the maths with actual efficiency figures at different rpm/torque points.


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## Moffer (Jan 28, 2017)

Got it. Thanks


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## Moffer (Jan 28, 2017)

What about the ICE range extenders on EVs? Are they incredibly inefficient and just used to relieve range anxiety?


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## dcb (Dec 5, 2009)

http://lmgtfy.com/?q=generator+gph+site:diyelectriccar.com


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## Moltenmetal (Mar 20, 2014)

You asked if a hybrid is more efficient than an EV wtih a gasoline range extender.

The answer is YES, unless you plug the EV into the grid to re-charge its batteries, and only use the gasoline range extender when you actually need to use it.

If you don't need the range extension, not dragging around a separate gasoline powerplant makes the pure EV even more efficient still.

Here, by "efficient", I mean how much source energy is used to move the car a unit distance. That's based on a normal electrical grid such as the grid in the USA currently. See the detailed calcs in the Union of Concerned Scientists report titled "Cleaner Cars- Cradle to Grave", which is easy enough to Google.

If what you're really interested in is GHG efficiency, that depends on your local grid quite a bit, and of course the efficiency of your ICE/hybrid. Here in Ontario, Canada, the pure EV wins hands down- our grid is only 9% fossil, all of that being natural gas, and we are under 40 g CO2/kWh. EVs here are a total no brainer!

If your sole energy source is gasoline, the hybrid IS more efficient. No point in lugging a lot of batteries around with you if you don't intend to use them to store grid electricity!

The hybrid battery is smaller and lighter, and is mostly recharged using regenerative braking- energy that would otherwise be wasted as heat. The torque kick that the electric drivetrain gives to the hybrid allows the use of a smaller and more efficient ICE without making the car perform like a slug, and the switch to a smaller engine itself increases fuel economy quite a bit.


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