Design fail: "Prius" bicycle without HSD

Discussion in 'Fred's House of Pancakes' started by NiHaoMike, Dec 7, 2012.

  1. NiHaoMike

    NiHaoMike Member

    Joined:
    May 6, 2012
    98
    16
    0
    Location:
    San Diego, CA
    Vehicle:
    2011 Prius
    Model:
    Four
  2. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    5,982
    3,781
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    I don't get your point...

    Hybrid bicycles have been around for a while. I have had one for over 5 years using Lithium Ion batteries. My coworker just bought a high end hybrid bicycle (like more than a Kia vehicle) too. If you have ever been to the far east they are very popular.

    I drive mine to work sometimes, even when it is just above freezing.
     
  3. NiHaoMike

    NiHaoMike Member

    Joined:
    May 6, 2012
    98
    16
    0
    Location:
    San Diego, CA
    Vehicle:
    2011 Prius
    Model:
    Four
    I'm not aware of any bicycle with an actual HSD. I can think of a number of advantages, such as being able to measure the pedal power very accurately and being able to regen down to zero by pedaling backwards. And it's also possible to use the bicycle as a generator (exercise bicycle) by putting it on a stand that locks the rear wheel and setting it to use MG1 as a generator.
     
  4. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    5,982
    3,781
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    There is a company in Boulder, CO who builds bikes. The electric motor is channelled with the pedal power through a planetary gear system, then through the bike gearing, then to the hub.

    Having 2 electric motors doesn't really make sense. We don't need a reverse on a bike. And we don't go fast enough to need backwards spin.

    Regen using normal brakes is enough. People don't pedal backwards when they break. It may be a novelty, but outside of the salesman, nobody is going to pedal backwards while braking to recoup a bit of energy. Especially since it is human power feeding electric power, and not the wall at that point. You never run out of battery on these bikes, so it does not make sense to do so. If you cannot commute with the bike without it being depleted, you bought the wrong bike for that use.

    All motors can do this. The problem is there is no concept of how much work powering even 1 lightbulb is. If you have ever hand turned a generator with no load and then with 1 lightbulb attached, you will know how much more difficult it is. And that is just feeding it enough to light up, not evenly.
     
  5. NiHaoMike

    NiHaoMike Member

    Joined:
    May 6, 2012
    98
    16
    0
    Location:
    San Diego, CA
    Vehicle:
    2011 Prius
    Model:
    Four
    The idea is to use two motor/generators as a CVT. In addition, by calculating the pedal speed and pedal torque, pedal power can also be calculated. That can both be used to provide a readout (which I've heard is often a greatly wanted feature) as well as act as a controller. So instead of pulling a lever to start using electric power, just pedal and it would automatically add a proportional amount of power.

    It could also try to pull power from the pedals at optimum angles by varying the effective gear ratio at different pedal angles.
     
  6. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

    Joined:
    Feb 14, 2010
    5,982
    3,781
    0
    Location:
    Rocky Mountains
    Vehicle:
    2006 Prius
    Model:
    Three
    Mine has both a manual control and automatic. The automatic control is a proportional amount of power. It is not hard to determine pedal power since you know the power through the electric motor that is being supplied by the battery, and you know the speed of the electric motor through the fixed number of gears and what gear it is in. It is pretty easy to then match power to speed so that it is keeping you at the perfect speed for whatever you are pedaling. If I pedal slowly, it assists very little. If I pedal fast, it assists a lot. Or if I want more/less then the automatic, there is an override. For instance pedalling up-hill, if I don't want to stand on the pedals, I just rotate the bar and more juice flows so I can maintain a lower human/machine power ratio then normal.

    The idea is novel. It is just not practical or solving anything that hasn't been done that is useful.
     
  7. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,058
    3,051
    7
    Location:
    Northern Michigan
    Vehicle:
    2006 Prius
    That would add a lot of weight and inefficiency to solve a non-problem. Given that bicycles operate over limited speeds, it is much better to use a single MG directly coupled to the drive system. Pedal input, if you really need it, can be measured from pedal pressure or torque at the crank.

    Tom
     
  8. hyo silver

    hyo silver Awaaaaay

    Joined:
    Mar 2, 2005
    15,231
    1,561
    0
    Location:
    off into the sunset
    Vehicle:
    2004 Prius
    Model:
    N/A
    Bicycles are already so efficient - mechanically, though not in an aerodynamic sense - that it's difficult to improve upon them. They're so light that any additional weight becomes a significant portion of their overall mass. Electric bikes work well for some people around town, but for a fit person pedalling more than short distances, the whole HSD system soon acts as dead weight that slows them down and decreases the overall efficiency.
     
  9. hyo silver

    hyo silver Awaaaaay

    Joined:
    Mar 2, 2005
    15,231
    1,561
    0
    Location:
    off into the sunset
    Vehicle:
    2004 Prius
    Model:
    N/A
    Following the Crocodile Dundee meme of 'That's not a knife', THIS is an aerodynamic bicycle. whittingham-sam.jpg
     
  10. Trollbait

    Trollbait It's a D&D thing

    Joined:
    Feb 7, 2006
    16,954
    8,124
    0
    Location:
    eastern Pennsylvania
    Vehicle:
    Other Non-Hybrid
    Is it design fail because have two motors like the Prius? Keep in mind that Toyota also uses Synergy Drive to name their hydrogen fuel system, at least on the FCV bus, which only has one motor.
     
  11. hyo silver

    hyo silver Awaaaaay

    Joined:
    Mar 2, 2005
    15,231
    1,561
    0
    Location:
    off into the sunset
    Vehicle:
    2004 Prius
    Model:
    N/A
    It's the weight, Trollbait.

    I'd consider hydrogen a fail, too, but that's another issue.
     
  12. a_gray_prius

    a_gray_prius Rare Non-Old-Blowhard Priuschat Member

    Joined:
    Jun 13, 2008
    2,927
    774
    0
    Location:
    IL
    Vehicle:
    2008 Prius
    Model:
    N/A
    Let's put this HSD-on-a-bike crap into perspective - your average car is maybe 20% efficient at turning gas energy into movement using a gears-and-clutches transmission. A cheap $70 walmart bike can do like 90%+ with its chain drive. The additional frictional losses from adding all that HSD motors and transmission crap is a huge net efficiency loss, not to mention the extra weight both statically and rotationally. There is a reason that racing motorcycles all use chain drives.
     
  13. hyo silver

    hyo silver Awaaaaay

    Joined:
    Mar 2, 2005
    15,231
    1,561
    0
    Location:
    off into the sunset
    Vehicle:
    2004 Prius
    Model:
    N/A
    "A bicycle is more efficient at turning energy into motion than any other machine or animal." I'm quoting loosely from Scientific American, about 30 years ago. I trust you'll forgive me for not getting it exactly right.
     
Loading...