By on May 10, 2010

Technology Review reports on Levant Power’s “GenShock” technology, which generates electricity by converting the kinetic energy of suspension travel into electricity. And electricity generation isn’t the whole story: the entire suspension is an actively-controlled, dynamic system that improves performance as well as efficiency in a turnkey package.

Levant has developed a modified piston head that includes parts that spin as it moves through the oil, turning a small generator housed within the shock absorber. To improve vehicle handling, the power controller uses information from accelerometers and other sensors to change the resistance from the generators, which stiffens or softens the suspension. For example, if the sensors detect the car starting a turn, the power controller can increase the resistance from the shock absorbers on the outer wheels, improving cornering, says David Diamond, the vice president of business development at Levant.

Given that this system returns the greatest efficiency improvements in large-truck applications, it might just be the shot in the arm needed to get Roland Burris’s electric HUMMER acid test off the ground. More realistically, this seems to be the kind of technology that could transform the commercial and military vehicle sectors, both of which have strong (non-moral) incentives to improve fleet-wide efficiency.

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18 Comments on “Electricity-Generating Shocks: The Key To The Electric HUMMER?...”


  • avatar
    Contrarian

    I guess this system would work great on the potholed, sinkholed New York Thruway, but not so much on a nice smooth southern Interstate.

    Somehow the energy budget on this concept doesn’t intuitively add up to any useful amount. It smacks a bit of perpetual motion.

    • 0 avatar
      cdotson

      Spoken like a true New Englander.

      If there’s one thing my years in Georgia and my present life in Virginia attest to it’s that the right-to-work southern states have enough heavy truck traffic to ensure your “smooth southern interstate” is purely a myth.

      Not to claim I’m well-traveled, but I have yet to go anywhere that I’ve been impressed by the preponderance of smooth roadways. And I pay attention to such things as a pickup driver.

    • 0 avatar
      gslippy

      West Virginia’s roads are quite smooth, thanks to the efforts of Senator Byrd and his ability to serve his home state.

  • avatar
    twotone

    At what cost? Interesting technology in theory, but how many miles would you have to drive for the electricity generated to pay for the extra cost of the shocks (no pun intended).

    Twotone

  • avatar
    Stingray

    The concept looks excellent. Suspension is continuously working. How much will it cost is what bothers me. Also the durability.

    And sorry for my ignorance, but how can this technology help save fuel in a Class 8 truck?

  • avatar
    L'avventura

    From my understanding, this system operates by passing hydraulic fluid through a turbine to generate electricity. Given the volume of hydraulic fluid and given the equivalent size of the generator, this system doesn’t seem to be able to generate significant electricity for a passenger hybrid.

    Which is why I guess they are focusing on military and commercial trucking applications. Larger vehicle weight, larger shock absorbers, more hydraulic fluid, larger turbine and generators to produce electricity.

    They are claiming 10% savings, which could be significant depending on what the added cost of these GenShocks are relative to a comparable shock absorber. The biggest issue I see is that to utilize this generated electricity these heavy commercial trucks would need to be hybrids.

  • avatar
    Greg Locock

    “They are claiming 10% savings”

    If they are then there’s your problem. Look at your current shock absorbers. Do you seriously think that they can absorb 10% of your engine’s power for very long? Because that is what they are effectively claiming.

    • 0 avatar
      Contrarian

      Exactly, the energy is waste energy from the engine and really the fuel. How much is currently wasted by converting into heat in shock aborbers. A few watts probably at the most in a car, perhaps a few dozen in a bigger vehicle. If ordinary shocks don’t get hot, they are not really absorbing much energy – and they are not exactly designed like heat sinks – so clearly they really don’t dissipate that much.

  • avatar
    benders

    Ha! I’ve had this idea. It came to me on a long, freeway drive.

    Even a passenger vehicle suspension moving an inch or two has a relatively substantial amount of energy being absorbed and dissipated.

    Vehicles would not necessarily need to be hybrids. The power generated from the shocks could unload the alternator.

    Greg Locock: An ICE at highway speeds is only generating a fraction of the rated power. If I remember correctly, a typical car requires somewhere around 20-30HP at speed on level ground.

    • 0 avatar
      chaparral66

      So lets say that it generates 2 hp. That means that it would would be converting what the shocks normally convert to heat into electricity. 2 hp is about 1.5 kilowatts. That is about as much heat as 17 100 watt light bulbs generate. Then figure that the system could not convert all of the energy to electricity and the efficiencies of converting that electricity into mechanical power to the wheels. At that point you need to assume the shocks are normally producing 4 hp or 3 kW of heat just cruising on the highway. That seems high to me.

  • avatar

    @Locock: the dampers don’t absorb engine power. Engine power is wasted pushing the car against resistance, which includes rolling resistance, wind resistance, and pushing the vehicle against bumps and dips. Power-generating shocks recover energy lost to bumps.

    It’s an inherently good idea… basically recovering waste energy… at the same time, variable resistance generators will give some of the same benefits of magnetorheologic dampers, while providing other benefits.

    • 0 avatar
      rpn453

      Locock is correct. The only energy input for the system is the engine. To improve fuel economy by 10% through modifying shocks, the conventional shocks would have had to be absorbing at least the equivalent of 10% of the engine output.

  • avatar
    shaker

    For this to work, the shocks would have to be given a larger share of the vehicle load (while making the springs lighter). If any active components fail, then the vehicle would not be able to carry its rated load, and handling would become unstable. The addition of this to a standard vehicle suspension would not likely have the energy return to justify the added complexity/cost.

  • avatar
    TR4

    10% savings = marketing hype. If this were even close to true you can bet that many would be removing their shock absorbers to save fuel. I don’t see this happening except for the 1000+ mpg economy run types.

  • avatar
    psarhjinian

    I’ve wondered if you could do something like this with piezoelectric crystals scattered throughout the car?

    From what I recall, walking generates 1-2W per step, and a car’s body offers stronger and more frequent motions: I suspect you could run much of the accessories (or charge a battery) quite easily.

    • 0 avatar
      TR4

      Those numbers do not compute. Say you walk 2 miles, or about 4000 steps. Does that mean you generated 4 to 8 kW? An athlete is estimated to generate 400 W for a short period of time! Also, if you are talking about per step it seems like the units should be energy (calories, BTUs, watt-hours) and not power.

    • 0 avatar
      psarhjinian

      Not the best article (because I can’t find a good one) is here.

      I do agree that the unit measure is a problem: it’s not 1-2W continuously, but 1-2W per “strike”.

  • avatar

    Interesting. If your car won’t start, you bang the dashboard with your fist several times. Voila, it starts. People tried that for 100 years. Now it might work.


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