Compressed Air Motorcycle Breaks 80 MPH With Ease

Being full of hot air usually means you lack substance. Fortunately for the makers of the O2 Pursuit motorcycle, being full of compressed air means something completely different. Powered by nothing by a scuba tank full of compressed air, this motorcycle achieve speeds usually reserved for combustion engines without the emissions.

While electric motorcycles may be all the rage, they’re not necessarily the most cutting edge alternative fuel bikes out there. Electric vehicles still require expensive, energy-intensive batteries and electricity that’s usually generated by fossil fuels. Advocates say compressed air engines could be a truly emissions-free option, with much cheaper fuel, but there are still some major hurdles to overcome.

O2 Pursuit Compressed Air Motorcycle

Image via Dean Benstead

The O2 Pursuit was designed by Dean Benstead, a graduate of RMIT University, in Melbourne, Australia. True to DIY style, Benstead started with what he had and added only essential components to creating a working prototype. The Yamaha WR250R frame was fitted with a compressed-air engine, and a standard scuba diving tank, which substitutes nicely for the gas tank. Opened up all the way, the O2 Pursuit can travel over 60 miles on a single tank, and up to 87 mph.

O2 Air Powered Motorcycle Exploded view

Image via Dean Benstead

At first glance, the compressed air bike seems to solve all of the frustrating problems of an electric motorcycle, i.e. a big, heavy battery to tote around and long recharging times. But if compressed air were such a simple solution, we’d already be driving air powered cars, so there must be something more to it.

The biggest barrier to compressed air-powered bikes or cars is that there’s insufficient infrastructure to support it (sound familiar?) and there still needs to be power available to compress the air in the first place. Still, the technology has promise, which is probably why the O2 Pursuit was recently shortlisted for a James Dyson Award.

Beth Buczynski is a freelancer writer and editor currently living in the Rocky Mountain West. Her articles appear on Care2, Ecosalon and Inhabitat, just to name a few. So far, Beth has lived in or near three major U.S. mountain ranges, and is passionate about protecting the important ecosystems they represent. Follow Beth on Twitter as @ecosphericblog

    • phor11

      60 mile range? That’s pretty amazing.

      The only flaw I can see in the design is the fact that the tank valve is pointed virtually right at the rider’s head while he’s riding. That could be dangerous if the valve ruptured.

      • Jim Lillie

        Yea, REALLY amazing, almost too amazing as far as I’m concerned. I’d have to see it to believe that bit of (erm) hot air…..

        • Joseph

          Agree with Jim..There is way too much upside here to believe it is true…When I sold electic vehicles, we commonly boasted of a 100 Mile range when 72 miles per full charge was much more accurate… The superlatives that come from these optimistic manufacturers are always 3 years ahead of themselves.. IMHO…

      • Snurd Gerbly

        We must remember that this is a prototype. Of course there is potential for significant improvement, but this machine is a very elegant proof of principal. This idea has got legs.

    • Robert M

      I want one of these.

    • geo brecke

      Please! do have a little respect for reality, it’s totally lacking here..

      • hempev

        So true – do they even know how much energy it would take to compress enough air to get you even a few miles at highway speeds?

      • john

        trompes were used to compress air for trains in france in the past.
        waterfalls have much energy.

        • gbrecke

          John, why use the term ‘much’? Why not share the formula for how much energy is in waterfalls? Compressed air is heavy in losses, if it were a good idea, we’d be driving around on air today. I’m still waiting for a followup on this click bait page…

    • sspence65

      The biggest problems are the energy needed to compress the air still produces emissions and the losses in the process of compressing air. This is a non product.

    • beautiful

    • Devin Serpa

      Air doesn’t compress itself into a tank. If “Electric vehicles still require expensive, energy-intensive batteries and electricity that’s usually generated by fossil fuels” then where might one get the electricity to compress the air? The efficiency of compressed air systems are less than electric vehicles with the same sources, clean or dirty. So the best bet is still electric vehicles.

      • Max Phipps

        Hi i would agree but after all this is a prototype why not add a small compressor to the bike that can be powered by the current EV charging infrastructure and ‘recharge’ the tank ?

        • Snurd Gerbly

          There’s regenerative braking. The kinetic energy of deceleration can be used to power a resistive load – a compressor, in the case of an air-powered vehicle – while electric vehicles can turn motors into generators which put current into the battery. I believe they can be brought to a complete stop that way, requiring no other form of mechanical braking, other than a park/emergency brake.

        • Snurd Gerbly

          There’s regenerative braking. The kinetic energy of deceleration can be used to power a resistive load – a compressor, in the case of an air-powered vehicle – while electric vehicles can turn motors into generators which put current into the battery. I believe they can be brought to a complete stop that way, requiring no other form of mechanical braking, other than a park/emergency brake.

      • phor11

        The manufacture/disposal of an air tank vs a battery is also another consideration though.

      • Darin Selby

        I have a concept for compressing high volumes of low pressure air
        efficiently into a high-volume, high-pressure tank. I call it the
        ‘Airgulper’. A completely new and
        different way of looking at compressing air, removing the heat, to
        eventually make LN2. I believe that it would use only a fraction of the
        energy necessary to accomplish the same task. Please, do share with me your thoughts.

      • SamuelMartin

        Compressing air can be achieved with water, gravity, underground infrastructure and nothing else. Check out the trompe air compressor.

    • Ebikeguy

      Big, heavy batteries are a problem, but somehow big, heavy tanks to store compressed air are not? Even high-tech composite pressure cylinders weigh quite a lot. Oh, and the process of filling such a tank is quite inefficient when compared to charging a battery. Compressing air necessarily involves generating lots of heat, which is ultimately wasted energy.

      • MaxVonSpank

        A potential energy per pound comparison would be interesting

      • SamuelMartin

        Compressing air can be done without generating heat. Isothermic compression can be achieved with a trompe air compressor.

    • MaxVonSpank

      Bravo for creative thinking.

    • QKodiak

      You do realize that it takes a lot of energy to compress air right. Also, it lacks the raw torque of an electric motor. Some electric bikes have over 100 miles of range. This concept is really cool though. As far as riding experience, I think EVs have it in the bag. However, the relatively lightweight, low cost nature of compressed air powered vehicles will make them desirable.

      • SamuelMartin

        Compressing air with a trompe requires no energy once the system is set up. have a look at trompe.

        • QKodiak

          Interestin. The energy used to pump the water to the top of the device must be considerable. The size of these things is also considerable. You’re not going to have one in your garage.

          There must be plenty of good reasons why electric compressors have mostly replaced trompes.

          • SamuelMartin

            No energy needed to pump water, you use a stream or a river. Yes the size can considerable, as with hydro dams, oil wells; rarely set up solely for residential use. I’m sure there are plenty of reasons why electric compressors replaced trompes, but it’s debatable how many of those are “good” reasons apart for the current energy industry’s financial interests.

            • QKodiak

              A hydroelectric plant coupled with remote electric compressors is better than compressing the air on site and transporting the compressed air elsewhere. There’s no need for the Trompe, except in mines.

            • SamuelMartin

              I`d be curious to do the math on power generated, power consumed and environmental damage by the construction and energy transport over the lifetime of a dam versus a trompe. Remember that in 100 yrs, the compressed air would most likely be transported by vehicles that run on compressed air or electricity.

    • Stephen Kelland

      compressed air motors tend to freeze if the air temperature get below 10C

    • Duncan Cairncross

      A 10 liter tank at 200 Bar gives a maximum possible energy store of 2.7Kwhrs
      (If you can get the air out without cooling it)
      This is the same as about 20 Kg of Lithium batteries and will take a motorbike about 20 miles at a low speed

      • Darin Selby

        Where are you cominig up with your nujmbers? The gas cools down when expanded out of a tank to then first go through a heat exchanger. This pulls heat from the ambient air (free energy). For cold attracts heat.

        He doesn’t yet work with GULPING air into the tank, instead of compressing it, which would make the process much more efficient. Here is my idea to do so. Please do share with me your thoughts:

        • Duncan Cairncross

          Hi Darin
          The MAX energy you can get out is if you assume that you can suck enough heat from the surroundings so that you get isothermal expansion (Same temperature)
          If you make that assumption (unrealistically optimistic)
          Then the energy available is

          10 liters at 200 bar will expand to 2m3 at ambient

          Think of this as a 1m2 piston moving 2 meters
          The maximum force (200 bar) on the piston is 20,000,000N
          The average force is 10,000,000N
          The work done (energy) = 10,000,000N x 2 meters

          =20,000,000 Joules
          We normally use watt hours , 1 watt hour = 3,600Joules
          So the energy = 5,555 Watt hours = 5.5Kwhrs
          (looks like I missed a 2 out above)
          That is about the same as my battery pack = 45Kg
          and will take a motorbike 40 miles – at low speed

          Bearing in mind the initial assumption – isothermal expansion – would require a massive heat exchanger

          • Darin Selby

            Massive? How large is ‘massive’? Did you get to look at the ‘Airgulper’ concept for creating a rhythmic vacuum and gulping the air into the tank?

            • Duncan Cairncross

              Yes I had a look,
              it is irrelevant to the amount of energy that can be stored

              As far as the size of heat exchanger, that depends on two things
              The amount of power you need (energy flow rate)
              The amount of losses you will put up with

              More power = larger
              lower losses = larger

              As far as the air gulper is concerned it will serve to INCREASE the amount of energy you put into the tank WITHOUT increasing the amount that is stored

              For maximum efficiency you should strive for as quiescent a system as possible
              High air velocity is not your friend – it will eat energy and cause heat – not good

          • QKodiak

            Finally someone who can actually bring out real numbers to debunk the idea that this cool concept is somehow more efficient than an EV. If it can actually travel 180 miles at 60 mph in absolute silence, that would be great even if it uses more energy and has less torque than an electric bike. It costs far less to produce than an EV because there is no battery, and it’s lighter weight. It’s the poor man’s EV (indirectly). I wonder how long it takes to fill up and how much energy it uses.

    • carrmic

      I remember the air powered cars that were being worked on a few years ago made by MDI They had said at the time that they could install a small gasoline powered compressor that could work on the go and would allow the car to travel more than 2000 miles on one tank of gas.

    • SamuelMartin

      Combine this with a trompe air compressor industry and voilà!

    • Jeff Waller

      Larger air tank + lower operating pressures = greater range
      and enhanced safety with the ability to quickly refill at any
      auto tire air kiosk for a couple of bucks.
      Problem solved! Everybody wins!

    • Jeff Waller

      Such vehicles are best used as auxiliary transportation on travel trailers and
      RVs where the tanks can be topped using solar power off as you drive, sleep,
      fish, or swim. They are not suited for long-distance travel unless someone
      makes a startling discovery.

    • Jeff Waller

      Scuba dive shops!

      Nobody seems to have considered the obvious. Full tanks can be bought with a trade-in at any dive shop. These companies would love the added business. Divers already stop by to trade their empty tanks for full ones. The infrastructure is already there. Cars and bikes could even use a larger tank if necessary, or even use more than one tank.

      • Darin Selby

        Have you considered the energy loss associated with compressing air? When you compress a gas, it heats up. What do you do with that heat, just let it go to the ambient air? What about the noise of compressing air? Then, it cools tremendously when expanding. Heat exchangers are required to pull in the ambient heat out of the air, or that is also lost. On compressing it, why not place the compressor INSIDE of the tank, and then INSULATE it, so that it becomes like a little ‘pressure cooker’. The needed psi is reached that much quicker, and the NOISE is virtually non-existent. I call this design concept, “The Airgulper”, which utilizes a jet of air to create a back suction, and GULP high volumes of low pressure air into a high pressure tank, instead of trying to compress it with an external compressor. Each tank would be fitted with its own “Airgulper”.