Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How about a SUV with 33mpg CITY.

  1. Jul 23, 2008 #1

    Integral

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    With a Hydraulic motor and disel engine for a pump.
     
  2. jcsd
  3. Jul 23, 2008 #2

    brewnog

    User Avatar
    Science Advisor
    Gold Member

    Sure, there's nothing wrong with the concept. However, a well-designed Diesel will beat 33mpg any day with some slightly considerate driving.
     
  4. Jul 23, 2008 #3

    Mech_Engineer

    User Avatar
    Science Advisor
    Gold Member

    I'm curious what the efficiency of the hydraulic drive system is compared to conventional drivetrains?
     
  5. Jul 23, 2008 #4

    Integral

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Virtually every vehicle which runs a route with frequent stops should have such a system, they use regenerative braking. To brake the motors become a pump and recharge the reservoir. They can get about 80% of the vehicles kinetic energy back into the reservoir.

    They use a diesel to maintain reservoir pressure, since it is a constant known load they can run it at constant speed at the efficiency sweet spot.

    The hydraulic motors have max torque at start up, so once again it makes good sense to use these for stop and go driving.

    With proper choice of materials and cooling there is no reason you could not use water as the hydraulic fluid.

    Note that this is a pretty old article, the payback time was computed using $1.50 a galleon gas.
     
  6. Jul 23, 2008 #5
    This subject was discussed at this forum. See second last post:
    http://forums.hydraulicspneumatics.com/eve/forums/a/tpc/f/8541063911/m/4241052961
    Hydraulics could be good if you make frequent stops.
    http://forums.hydraulicspneumatics.com/eve/forums/a/tpc/f/8541063911/m/4721036991
    http://www.businessweek.com/magazine/content/06_38/b4001082.htm
    As for efficiency it is explained here. He’s using gear pumps but piston are only about 10% better.
    http://www.machinerylubrication.com...Next+Challenge+For+the+Maintenance+Department
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: How about a SUV with 33mpg CITY.
  1. How To? (Replies: 7)

  2. Robot how? (Replies: 5)

Loading...