Hybrid Bike to beat them all....PLUS 2 wheel drive!

Discussion in 'Performance Mods' started by andyinchville1, Dec 18, 2007.

  1. HI All,

    Just thinking about all the challenges of making a multi speed transmission for the happy time when it dawned on me that maybe the hybrid approach may be the best of both worlds and maybe the best overall situation (well until the multi speed tranny becomes a reality at least....then we could have a true multi speed hybrid...anyways that's for later)....

    OK.... so here goes, start off with a basic happy time motorized bike.... then add a full electric set up to it (front hub motor so that the rear hub may eventually be swapped out to a Nu Vinci to allow multi speed for the happy time)....

    We would then gear the happy time with a 32 t or smaller rear sprocket (assume a 26" wheel).....we would gear it high (engine wise) because we would rig the throttle so that the electric hub motor would get the bike moving initially(motors make the most torque starting a zero rpm so rapid acceleration from a standstill would be possible)and then switch off for cruise and top end....A " boost" switch may be added to allow the hub motor to help the high geared happy time up the steepest of hills...NOTE: may be able to use a left hand throttle to control the electric motor for 2 wheel drive!( let's go snow riding!)...just have to manually synchronize engine and motor speeds.

    So now we have rapid off the line acceleration (electric motor) ,
    then for cruise and high end we use the Happy time (since it is now geared intentionally high we have a rapid cruise at moderate RPM's AND and insane
    top end).

    If we encounter steep hills and the happy time needs help....no problem...Electric motor to offer assistance!

    PLUS....we now can have the ULTIMATE lighting system!...Why?...Because at cruise, the electric hub motor can act as a generator to recharge the battery
    and provide juice for all the mega powerful lights you care to run ( no more problems with small rub the tire bike generators or constantly buying or recharging batteries for the puny lights we now run)....well within reason but light years above what is available to us now...

    Oh, you can also save your brakes from wearing out too, because when a motor generates electricity it provides braking....wow a jake brake for a bike?!?

    Also, in case you encounter or want to be stealthy you could just use the
    electric until the juice ran out then you could Happy time it home....electric may be good around police too if you are paranoid.

    So what do you think? The best of everything....well except for a little more weight and cost?


  2. Bean Oil

    Bean Oil Guest

    Sounds great! but it would be quite a bit heavier... and cost a bunch more.

    I do like the idea, though: instant electric motor torque from 1 rpm all the way to (in the case of a 32 tooth), say, 17-18 mph... then pop the clutch and Happy Time you go! Brrrrrrrrrrap! LOL. Cruisin' at a steady 40 mph! Wow!

    Thumbsup to you, Mr. Inchville (I call you Andy Inchville... although I realize it's prolly Andy in Ch-ville...) :D

  3. Alaskavan

    Alaskavan Guest

    Interesting idea. Just try to avoid having the two wheels rotating at different speeds. That could be troublesome.
  4. ulmo

    ulmo Guest

    Hybrid systems work well with vehicles that have big mass and need to accelerate and decelerate frequently. They accumulate vehicles kinetic energy electrically to accelerate it later again.
    It would need several sensors and cental processing unit to coordinate gas engine and electrical engine/generator work unless you want to do it manually, but that wouldn't make sense. I can imagine much simpler version, which consist of gas engine driven generator, electrical hub engines and battery between them. That would lead to simpler controls, we only need to control current to electric engines.
    But again, that system means unnecessary power losses in additional electric systems (generators/engines/batteries) and therefore reducing system's fuel economy.
    Braking with electric engines... i dont think it can be done that simply because of the need to adjust braking power precisely, combining mechanical and electrical brakes.
    Anyway it makes bike much heavier and expensive. What makes motorized bicycles so interesting is their simplicity, low cost and lightweight.

    But if we already fantasize here... I'v been thinking about using exhaust gases to rotate generator to get power for lights... a little turbine attached to small generator would do work, would need also expansion chamber between turbine and engine to even pressure. :)
  5. dbigkahunna

    dbigkahunna Guest

    I have been thinking about this over-reving with the front pulling harder than the rear, and I dont think it will make any difference. If the front electric is turning faster than the engine is allowing, then the centrifugal clutch will keep things in ballance. Same with the engine pulling faster than the electric motor. Where I see this working well is on a steep hill. You use the power of the electric motor assisted by the IC engine. As you get to the top of the hill, you ease off the electric power and allow the engine to do the work. The 2 strokes loose power when the RPM's drop. Using the electric motor to keep the IC engine speed constant will result in better fuel economy. If we were taking about doing this at oh say 80 MPH, I could see some issues wiht the push-m-pull-u of an electric/IC bicycle. The oly issue I have wiht this set up is where ya put the dadgum batteries? If you have rack mount, then the only place is between the seat the and bars. If you have some decent size batteries they will be between your legs. If you have aframe mount, then the batteries can go on a rack, but then you get limited by which engine you will use. I agree, the electric/IC hybred motored bicycle is a great idea. From what I have found this would be in the $2K range, not counting the duct tape and plastic wrap required for all electric applications
  6. hybrid 2 wheel drive.

    I agree entirely with Ulmo but I'm sure it could be made to work. Remember not all hub motors have regenerative braking though. Hybrid systems don't need as much electrical storage so you can skimp on battery size if you've got enough voltage and are keeping it charged via regen. Perhaps carry a small battery on each side of the front hub for a short, low resistance wiring setup.

    To keep things in perspective, remember that all the energy in a fully independent hybrid system still originates from your ICE. Don't expect to be able to power lots of lights. It's difficult enough to find wasted energy in small engine vehicles that can be reclaimed.

    Generally a hybrid system has to have enough opportunity to use otherwise wasted ICE energy and stored momentum to recharging the batteries, like during idling time at stops, cruising at partial throttle and of course during deceleration and going downhill.

    With a parallel hybrid setup (no generator on your ICE) you lose charging ability when not rolling. With a series hybrid setup (ICE to generator to batteries & electric motor) you lose the efficiency of direct ICE propulsion when that would be best, like when cruising at a steady speed. The efficiency of transforming mechanical energy to electrical to chemical (battery) to mechanical again is low overall, so for it to be useful, there has to be PLENTY of energy available that would otherwise be wasted.

    A car needs only an average of 19 hp to keep a steady, typical highway speed, but its engine has to be much stronger than that for acceleration. The extra engine size in a car is wasteful at cruise. If it gets a hybrid setup it can use extra engine capacity to store up electrical charge in batteries and/or a smaller ICE can be used. The electric motor takes up the slack for economy and/or power.

    A series setup is best for very massive vehicles (like trains) or vehicles that do a lot of stop & go & have a great deal of otherwise wasted energy due to decelerating or descending hills. Only then is it efficient to have a small ICE constantly running at its most efficient fixed RPM and load to compensate for energy lost in transfer from mech. to electr. to batts & mech. again.

    I think it would be fun to coordinate both types of power on a parallel hybrid bike on which it could be used for performance enhancement much more than for economy.

    Just make sure there will be AMPLE opportunity to pump energy back into the batteries. There isn't much extra energy available to save up if you live in flatlands, have a lightweight, nonaerodynamic vehicle and have a centrifugal clutch. A larger hybrid vehicle travels at less than full speed much more than we do. They can be using a computer modulated amount of excess ICE power to charge batteries at those times. We don't have it to spare. Since we have to drive at or near top speed to keep up with traffic, as soon as we dialed in some regen we would slow down, which may not be a problem at other times.
    When decelerating or going downhill, you need to decouple the ICE so your engine compression won't slow you down. That's when you want the hubmotor to suck up that momentum. Regenerative braking is simply temporarily switching your motor to a generator. Since we can't disengage our centrifugal clutches when decelerating, we are wasting momentum in spinning our engines against compression. That energy should be going into spinning the hubmotors in regen phase instead.

    The most authoritative figure I can find is about 60% efficiency for regenerative braking in sophisticated systems. The bottleneck is the battery.

    Heavier, faster vehicles store more momentum than we can. Much of ours is bled off with wind resistance due to our upright posture and light weight. In a long deceleration to a stop with clutch disengaged, and without using brakes, 100% of that stored momentum has been lost to wind resistance alone (except for rolling resistance that is lost whether you are in regen. or not). Here's where a streamlined recumbent bike and hard regen braking would be better.

    If you are not relying entirely on your ICE and riding habits to charge your battery, it's not so critical. Just keep your batteries charged from an outlet whenever possible. Not so good for those who ride all day.

    The tricky part of this is reclaiming energy from momentum by disengaging your ICE and coordinating regen and mechanical braking, using your mechanical brakes as little as possible.

    Commercial systems have the electronics to accomplish these things and more. We would have to get creative with mechanically coupled throttle-controller-clutch-brake arrangements.

    Keep in mind, you'd have a great deal more freedom to assemble all of this complication and weight into a trailer. But then you could simply use as large an ICE as you wanted from the beginning!
    Last edited by a moderator: Dec 26, 2007
  7. beast775

    beast775 Guest


    well after about 400 miles on this,i ripped it apart.it was a great ride but didnt like the weight,it did regen,about 2 volts per 50 miles,it was really powerful off the line,i would take traffic at lights.didnt like the weight or charging the batterries,checking mechanics,was like a full time job.600 watt front ehub wired to 43cc mitsubishi chain drive.:shock:

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  8. Blue Max

    Blue Max Guest

    I'm really interested in tackling some serious inclines and am considering a cyclone type chain drive, along with the 70cc frame mount. I'm thinking the cyclone wont be costing me much over a grand from prices I've seen. As much as I 'd like to use the 1000 watt option, I'm pretty sure the Chinese thumper wouldn't keep up, even with the clutch in! lol Would be a shame to have all that juice and not be able open it up on level tarmac. But would be ideal for bearing the load when scaling a 'get off and walk it' type hill.