Using alternator as starter engine

16365 Views 26 Replies 9 Participants Last post by jared2009gregg, Mar 12, 2022

electric_driver

Discussion Starter · Feb 10, 2017 (Edited)

Hi,

I'm building a hybrid vehicle, and for this I need to use (one of) the alternators attached to my internal combustion engine as a starter engine. My initial idea was to just use a starter motor, but since I can't use the retract function of this, it needs the starter engine to remain connected all the time, and (besides that this lower efficiency), it would also rip the starter engine apart due to the sheer force when running at full speed. So obviously I need to use one of the alternators as the starter motor.

The internal combustion engine I'm using is a 17 - 20 HP internal combustion engine. It runs at between 6000 - 7000 rpm (say 6500 rpm)
The most efficient rpm for the alternators (regular running, NOT starting !) is between 4000 rpm and 5500 rpm. So, I'll be using a 65/40 or 65/55 gearing in between the internal combustion engine and the alternators. I'll be using not gears, but a toothed belt for this, probably in a V-type setup.

The alternators are 2 Leece-Neville 8SC3009ZA's (well actually Prestolites, but these have the same specs as the Leece-Nevilles). They run at 24 Volt (output of the 2 is hence 48 V). Power curves are at
http://www.prestolite.com/productinfo/alternators/8SC3009ZA/8SC3009ZA_curve.jpg

The batteries the alternators charge will probably be 4 batteries of 12 Volt (with 2,3Ah), in specific, these ones (as they're quickly rechargable):
http://cs-shop.de/LiFePo4-Motorrad-...40A-fuer-kleine-Motorraeder-Roller-bis-350ccm

I'll actually be using 2 sets of 4 batteries, so as to allow running the engine from 1 set, while charging the other set of batteries.

Anyway, the question I have is: won't this damage my alternators (as they're not intented to be run as engines, and I'll be starting (and stopping) the engine a lot), and is the power of the batteries (140 A @ 48 V) sufficient ? I assume so, from the power curve, but I still like to hear a second opinion, and hear that it is indeed possible to run these alternators as engines without damaging them.

If the above won't work, will some other batteries from cs-shop (in particular the 150A @ 12V, with 2,5Ah) be able to do it, and/or do I need still other batteries.

Note that the batteries have so little Ah mainly because I like to keep the vehicle very lightweight.

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electro wrks

· #21 · Feb 17, 2017

ed: You see initially GM had the Volt set up just as you describe your set-up with no mechanical link between the ICE and drive wheels. They quickly realized that in important driving situations such as hard acceleration, sustained freeway driving, low battery state, and others there was a distinct power and efficiency advantage to having a direct mechanical link between the ICE and the drive wheels. This is by itself or in combination with the electric motor/generators. The electric motors/generators and the ICE, through gear trains, clutches, and a lot of software, are set up accordingly.

As far as charging the batteries at a high rate and providing power to an electric motor at the drive wheels: there's no free lunch here. To do both and maintain normal driving abilities of the car (i.e. good acceleration and freeway speeds) you would have to have a more powerful, more gas guzzling ICE. This totally defeats the purpose of trying to increase efficiency and reduce gas consumption!

The Volt only partially recharges its battery from the ICE partly for this reason. Also, they do this because the cost of recharging the batteries from the ICE, if all the expenses are considered, is at least 5X the cost of recharging from the utility grid! They encourage you plug in whenever you can-to save money. The plug-in version of the Prius was also developed to take advantage of this cost savings

You're trying to reinvent the wheel here. To do it, you'll have to come up with a much better wheel!

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dcb

· #22 · Feb 17, 2017

electric_driver said:
I still think it differs from my system, just because I have no such mechanical linkage anywhere in my system.

I guess the problem is that "your system" isn't your system, the very first hybrids were people putting generators on their electric vehicles. It is literally the most simplistic way to make a "hybrid". But like a few people have tried to tell you, with all the conversion losses it is rather inefficient. Your focus seems to be on trying to put lipstick on that pig, because you invested a lot of time/money before really understanding it. Build a bridge and get over it.

the Prius allowed it to mix in parallel because it is more efficient than "pure" series all the time.

With all the conversion losses series is about the worst. It matters not if your engine is at peak bfsc if you lose %40 getting it to the wheels.

Besides the prius engine runs in atkinson mode (they increase the expansion ratio via valve timing), it is more load sensitive than rpm sensitive. And mg1/mg2 can do whatever they need to. You essentially get an "electric" continuously variable transmission w/overdrive. With a small battery to help accelerate and reclaim braking energy, and allow the engine to shut down completely when not needed (and also which provides instant 1000 rpm engine starts that reduce emissions, as apposed to a 2hp bump and chug start).

There was a team in the automotive x-prize that attempted a series hybrid, hoping to sync the motor and engine up magnetically, but it doesn't sound like it would work well except under very specific operating conditions. With power split (prius/volt) you get the best of both worlds. I would study the prius power split device first, volt would have gladly used it if it weren't for patent issues (AHEM!!), but they had to change it a bit to make it look different.

http://www.ucsusa.org/clean-vehicles/electric-vehicles/series-vs-parallel-drivetrains#.WKdHETsrKCg

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electric_driver

Discussion Starter · #23 · Feb 18, 2017 (Edited)

electro wrks said:
You see initially GM had the Volt set up just as you describe your set-up with no mechanical link between the ICE and drive wheels. They quickly realized that in important driving situations such as hard acceleration, sustained freeway driving, low battery state, and others there was a distinct power and efficiency advantage to having a direct mechanical link between the ICE and the drive wheels.

dcb said:
With all the conversion losses series is about the worst. It matters not if your engine is at peak bfsc if you lose %40 getting it to the wheels.

dcb said:
like a few people have tried to tell you, with all the conversion losses it is rather inefficient. Your focus seems to be on trying to put lipstick on that pig, because you invested a lot of time/money before really understanding it. Build a bridge and get over it.

I hear both your comments on series hybrids, but still see value in a very simple (pure) series hybrid system. This as:
* it is simpler and cheaper to repair when broken down and replacement parts are easier to obtain (since they don't need to be very specific)
* it is much cheaper to make
* they still offer energy consumption benefits over regular (non-hybrid) vehicles, especially when used in situations with a lot of traffick (a lot of starting/stopping) -they will be less efficient than parallell hybrids or complex hybrids like the Prius/GM Volt but that's a trade-off with the other benefits mentioned here-

I just want to try it out and see whether I can't make this work, and create a vehicle with the above benefits. If it won't work, I'll also accept this (the reason I'm doing this is to create environmental benefit, not to gain huge financial rewards). So if it doesn't provide that, I would just scrap the idea and focus on either changing the project or focusing on something else.

electro wrks said:
As far as charging the batteries at a high rate and providing power to an electric motor at the drive wheels: there's no free lunch here. To do both and maintain normal driving abilities of the car (i.e. good acceleration and freeway speeds) you would have to have a more powerful, more gas guzzling ICE. This totally defeats the purpose of trying to increase efficiency and reduce gas consumption!

I'm not trying to:
* charge the batteries (which aren't used right away)
* and drive the electric motor straight from the ICE

I'm trying to charge the batteries -which ARE used right away-
OR drive the electric motor straight from the ICE (= fail safe)

Also, increasing efficiency and reducing gas consumption isn't my only motivation on doing this. The point really is about making a propulsion system that makes road transportation more ecologic. That goes beyond just increasing efficiency and reducing energy consumption. For instance, if compared to a fossil-fuel powered (non hybrid) vehicle, my hybrid system is used whereby a biofuel is burned in the ICE, and the components of my hybrid system are easily recyclable -and there's very little or sometimes even no efficiency gain-, then I allready consider this an ecological merit, so a success. There are many other possible eco-gains that could come out from my project as well. I'll just keep tweaking things and look at the outcomes.

Anyway, there's little point in keeping to discuss the theory of my drivetrain; rather I need to build it, so it's better to skip ahead to my other post.

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electro wrks

· #24 · Feb 18, 2017 (Edited)

OK ed, obviously your not going to be constrained by the laws of physics or any semblance of logic in pursuing your dream. That's OK. You have to admire your tenacity and thickheadedness. As you build your dream machine, please take plenty of photos and chart your progress towards your dream. If it works out, I'll be the first to acknowledge your accomplishment. Be aware though, in my career and life, I've seen the scum of the earth-some of the most despicable human beings- push the most unbelievable crap as the truth.

If it doesn't work out, please let us and the rest of the world know. Maybe it'll prevent some foolish person wasting our time and leading us down some twisted, dead end, logic rat hole.

Then again, it could get you elected president of the United States!

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ICEICEbaybee

· #25 · Feb 20, 2017

I like your idea but why not move your starter motor in place of that alternator and be done with it?

You are being innovative. Nothing wrong with that. Let conventional individuals be just that. The trick will be to find a pulley the size of your flywheel to bolt on your crank to keep the correct ratio constant.

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tinkeringgreg

· #26 · Mar 14, 2017

one thing i think you are overlooking is that you cant supply 12 volts to an alternator to make it run as a motor because of the rectifier diodes in the alternator. With that being said alternators can be run as a motor but you have to supply a three phase AC voltage directly to the stator while also supplying 12 DC to the field (rotor) you would also need to disconnect the alternator output cable while it is being used as a starter motor. I also doubt it will have enough torque to spin the engine

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jared2009gregg

· #27 · Mar 12, 2022

electric_driver said:
Ok, first for this post (which bugged me):

I didn't patent it for any financial rewards. Rather, I patented it out of ecological reasons. More precisely, it was an idea I had which I felt would be soon discovered by (commercial) companies and might be patented by them. Once patented, they could then even block the idea of being used by anyone.
So although I could have chosen not to patent the idea at all, that's not how things work and if I wouldn't have, it would (or could) have resulted in environmental damage.
I intent to make the idea available to as many commercial companies as possible, under my own terms (which aren't dictated by commerce but by ecology).
In any case, my patent would only affect companies, I don't intent to sue private people (hobby builders) that would use the system I patented.

I don't know the brand of the starter motor I have (which works to start the internal combustion motor). That said, it is powered by a Rocket 30-12 battery. That battery delivers 12 V and the amperage is:
under 13,8 V: unlimited amps
from 14,4 V and up: 7,5 Amps maximum

So you mean the electric motor ? This motor is connected to the wheels (drive shaft), and not to the internal combustion engine, so that won't work.

So, I gather that the alternators do have enough power overall, but they just don't have the right gear ratio in order to have enough power to start the internal combustion engine.

There are 3 options I can see to overcome this:

either use one of the alternators only as starter motor, and change the gear ratio of it.

or buy a different starter motor that is capable of handling the high rpm and add that to the toothed belt assembly (by means of a disc with the correct gear ratio)

or change the assembly so the starter motor can be disconnected, but using another way (using a clutch)

I prefer option #2 and #3 of these, since I didn't bought an internal combustion engine with 17-20 HP to then just use it at 30% or so of its power output, and also didn't buy an expensive alternator to then use it as a mere starter motor.

If I use option #2, what brands/models of starter motor exist that can handle this high an rpm ?
Also, the brand/model chosen would best be able to run on one of the battery packs I'll assemble (so the battery would supply 12 Volt @ 140A). The idea I have is to have the system select whichever of the 2 12V, 140A battery packs which is currently still fully charged (the battery packs are charged/used intermittently). The alternative is to use a standard battery (normally used with the starter motor) but the downside is that this battery would then not be recharged (unless the starter motor too can act as an alternator, but that would complicate matters, and probably isn't easy to get a hold of).

If a rectractible starter motor is really needed, how do I best set this up (can I combine gears with a toothed belt drive, ...) ?

Simply put, if the electric motor is connected to the same drive axle as the combustion engine then it should be quite obvious on how to start this technology. Install a clutch system that would allow the drive sprocket of the combustion engine to freespin while throwing great amounts of battery power to electric motors, ( which will start the moving process), then release the clutch, (which will engage the combustion engine to turn over and crank), lastly once you have ignition on combustion engine drop all power to electric motors by means of a toggle switch and Viola you have everything that is needed to start and drive your hybrid. Also you can pull power off your magneto of the combustion engine to recharge your batteries for your electric motors. And yes an alternator would be a great motor for a hybrid cart. Good luck and safety first.

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