Gas/Electric Hybrid Systems

SimpleSimon

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Okay, this really started (for me, at least) with augidog’s “Creative Interpretation” thread, but I’ve been asked to start a thread, so I will.

"Creative Interpretation"

Okay, I kind of like that term. Here's my own variation on that theme for you.

Most states have laws addressing "motorized bicycles", and for many states, the laws treat an electric motor "assisted" bicycle a good bit differently than a gas engine "assisted" bicycle. I've been wading through the state laws addressing motorized bicycles, mopeds, and motorcycles for the last couple-three months now, in my spare time. Being disabled, it's the one thing I have a plentitude of.

Here's my take. E-bikes are, pretty much across the board, easier to get away with, so far as the law is concerned. With some variation, most states allow up to one horsepower electrically powered bikes pretty much anywhere a bicycle can go, including on bike paths. The problem with e-bikes is the batteries. Heavy, expensive, limited lifespans, and much too short a range for lots of folks.

Not one single state code I have read (over 35 of them, so far) adresses where the electricity to power the bike comes from. Not ONE of them.

Can you see where I'm headed, here? Those same small gas engines we see used to directly power the bikes are also used by lots of companies as the power sources for small portable generators, up to about 1 kw (or greater) capacity. Why not follow augidog's lead, and build a hybrid bike? A true hybrid, not a two "prime-mover" setup as he has implemented?

Forget batteries, except as a peak demand power sink. Run the generator to make the electricity, use the electricity to power the bike. Legally, it's an e-bike. Practically, it has the range of a "gas-assist" engined bike. Set the generator up to sense demand, let it run in its power band at an rpm where it is most efficient, and in effect get over 200 mpg. When max power isn't directly needed to power the motor (most of the time, really), let it keep the battery at max charge.

So - who wants to shoot holes in that one?

Combining the above with the ongoing thread post in the Electromotive thread;

I've looked at the motorized bicycle laws for about 40 states now. About 2/3 of them treat electric assisted bicycles a good bit more leniently than they do gasoline engined ones, if they recognize a difference at all.

Not one of those states addresses the source of the electricity. NOT ONE. The only things the law addresses is maximum attainable speed under electric drive, and maximum allowable power of the drive system. Typically, that's 20mph on level pavement, and/or various wattage ratings (varying from 200 watts to 1125 watts) and/or horsepower ratings (using 750 watts = one HP).

Since the law does NOT address the source of the electricity to power the bike motor(s), a simple small 2 stroke engine/generator set charging a battery as a power demand modulator is perfectly legal, and any cop who writes a ticket on the basis that the bike is gas powered is on a fool's errand. Sure, you might have to go to court - in which case hold out for a jury trial. Most importantly, know the law in your state, and local jurisdiction; keep a copy of it in your tool pouch, and most courteously offer to share that with the cop who stops you.

Yes, there are losses in such a system. That is unavoidable. They can, however, be made quite small, and since you are charging a battery as a power reservoir, you can set your generator up to charge at its most efficient rpm setting. Very probably, you can offset many of the losses of efficiency from variable throttling of the engine used as a prime mover.

And
I am working on a genericized simplified plan at this time. The electronics for control are really very straightforward. The major issue is that component choices in one part of the system must be met by compatible component choices in other parts of the system. Fortunately (or perhaps not, for some), the major choice is already made for you by your state laws, if they address electric assisted bicycles. That is - how much power can I apply? How fast can it run?

The second paragraph of that last post is a separate can of worms.

I invite any and all ideas, critiques, addendums, whatever you might have to say. I will say this - such a system bulks up a good bit, although you might be surprised by how small/light it can be made if one is willing to spend the money (look at Matt Shumate’s electric recumbent).

For my own purposes and needs, I want a trike. Either delta or tadpole, although I personally prefer a tadpole configuration. Delta trikes are MUCH more common, and much easier to get as already functional bikes. So, I am working on such a system plan, as I told Mountainman:

I am, at this time, putting together a simplified plan to implement just such a system for a delta trike. It will be somewhat generic, as of course the individual component choices made by each builder will vary somewhat. The major system components are, however, pretty much the same as I envision it:

1) 2 cycle gas powered portable generator, as light and physically small as can be reasonably achieved, capable of producing approx 1 KW;

2) A battery pack - number/size of the batteries again being somewhat variable, but practically speaking capable of at least 24V, and a range of at least 15 km at full charge without the generator;

3) Motor/controller capable of powering the drive wheel(s) with reasonable acceleration, and of maintaining 20 mph on level ground; and

4) capable of propelling a 300+ lb load as described above - your average guy being around 200 lbs, the bike and system being another 60+, and a small payload capacity.

Multiple gears, with electric power delivered through the bike's pedal drive train, are a plus; as would be regenerative braking. Lots of little add-ons that would be nice; for instance, a good, bright lighting system.

Still working on the details at this time. Feel free to take the idea and run with it - from my point of view, the more bikes on the road the better, and such a system does not lend itself readily to abuse with high top speeds, etc.
 

Mountainman

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SimpleSimon -- I must say - this idea has sparked my minds eye !!! It has been A LOT OF FUN watching you develop your thoughts in regards to said project.. I wish you well and look forward to keeping informed on your progress.. I am also interested in either building up or buying one of these HYBRIDS someday.. Until then -- Happy Riding from - Mountainman
 

mac66

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Hey, my first post.

I am here primarily to learn more about motorized bikes because I had an idea of a putting together a hybred pusher motor. Low and behold there are others out there with similar ideas.

My idea was to have either have an direct drive electric motor or a hub motor on a single wheel trailer with a small gas generator. My thinking was the electric would be stealth/quiet mode, the generator would simply recharge the batteries when needed. Then I thought, why not use the generator to recharge while in use which would give one real long range. One could use the battery in the city or at night (stealth mode) crank up the engine out on the highway. Or of course, take the trailer off and have super stealth mode.

Stealth mode IMO, is important at least here in Michigan, because the laws are somewhat ambigious about motorized bikes. The police here pretty much ignore small electric and gas scooters/go-peds unless you are being stupid on one.

Anyway I am interested to see how this thread develops over time.

BTW, back in the day, someone was marketing a tiny 300-500W 2 cycle gas generator that was about 8" square. It was maketed in camping mags etc shown with a coffee cup for scale. Something small like that would be a interesting choice.
 
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vegaspaddy

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delta trike is my project for next year,

here a links to two small generators found all over the internet

http://www.northerntool.com/webapp/wcs/stores/servlet/product2_6970_200313480_200313480

http://xmcparts.com/wen850watt2-strokeportablegeneratormodel850.aspx

i already have my tadpole electrified, but if it was able to charge the batteries and switch to gas that would be way cool, not sure if i could retrofit this one, hence the new build next year....

http://www.motoredbikes.com/showthread.php?t=9468

need to save money and convince my wife !!!!!!!!!

watching closely,
 

SimpleSimon

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Good to see some interest. I like the trailer idea, although a single wheeled trailer requires a lot more complex hitch to remain stable. I also REALLY don't like the pusher concept - it is in effect an articulated vehicle with all power inputs in the rear portion, all steering inputs in the front section. Doable, but it complicates your hitch point issues a good deal.

All that said, a very small electric motor mounted behind the seat tube with a compact jackshaft arrangement feeding a free-wheel capable chain ring inside the main front chain ring(s) can easily provide the desired power, and let you just pedal it any time you wish, and still leave you with all of your shifting capabilities. If you set up your power trailer with a couple of good batteries along with the generator, all that runs up the hitch tube is your power/controls cable.

Northern Tool sells (for $129) a small two-cycle gas engine powered 1 KW portable generator. Really good hi-output electric motors aren't cheap, but they aren't prohibitive either, and they can be smaller than a pop can.

Thanks for that link to the other site selling that generator. Even better price.
 
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vegaspaddy

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there is a build around here which istumpled on a couple of months ago of someone living down in florida who had a genator hooked up to his electric system, i dont think he was using it to actually power his machine just to keep his batteries charged, sort of like regenerative braking. Will try to find the link and post.

p.s. have you seen the setup staton is working on.

http://www.staton-inc.com/Details.asp?ProductID=3320
 

vegaspaddy

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still using batteries but,

As you can see, this is a pretty simple and crude setup at the moment. Just a power hub mounted on the trailer, with 4 7 a/h batteries. Then there is a 31cc trimmer engine driving a 10 amp permanent magnet motor to recharge the batteries, and run a few accessories. (like the 55 watt halogen headlight I have yet to install) I run the engine up till the motor is putting out about 56-60 volts. As long as the biike is using power, it doesn't seem to bother the batteries. The whole generator setup weighs maybe 12-15 lbs. Also I have a dp/dt switch that kills the engine, and discnnects the generator for those instances when I want to glide soundlessly past some one. Flip the switch, and the generator restarts the motor after the situation is past.

second thread reading,

so it seems there are a couple of generator to battery to motor builds exist, cutting out the middle man (the battery) is going to be the HARD part.....
 
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SimpleSimon

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mac66, that mini-generator you posted a pic of is essentially identical to one I used extensively in South Africa/Lesotho/Botswana 30 years ago. The one I had there was built by a company called Hedley, in South Africa, and was about 20 years old when I got it. 4 cycle single cylinder 28 cc engine, it was set up to make 12 volt or 220 volt power, normal output was 350 watts. The single most reliable small engine I've ever used - I put probably 150 hours a month on it or more, and all I did was change the oil every 500 hours of operation, wash out the air filter element, and keep it fueled up. The guy I bought it from (for R20.00) told me not to ever let it run dry, as it would run really lean and overheat, and blow the head gasket. Said it had happened to him twice, with no other damage. Wish I still had it, but it was taken by somebody in the SADF patrol group I fell afoul of in western Botswana (they claimed I was in eastern SW Africa).
 
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