http://citycyclingedinburgh.info/bbpress/ CityCyclingEdinburgh Forum » Topic: Really zero emission? Car running on air. en Wed, 24 Jun 2026 13:19:13 +0000 http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73752 Sun, 10 Jun 2012 21:50:25 +0000 Tom 73752@http://citycyclingedinburgh.info/bbpress/ <p>Aren't these engines all just basically huge refrigeration units? </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73740 Sun, 10 Jun 2012 13:56:29 +0000 Smudge 73740@http://citycyclingedinburgh.info/bbpress/ <p>Wont be Land Rover based, *far* too heavy for that sort of thing. Last bikes I saw them using were Honda enduro bikes (XR250iirc) and some quads,sure it wasn't maybe a trial of a compressed air outboard or some-such? (would be an easier conversion from existing torpedo technology). The problem with the UKSF is that there are too few of them to start developing our own (very expensive) technology for them. The norm is to buy in whatever they need that the "normal" forces don't use for instance the Diemaco rifle.<br /> Ping him for more detail and see if he's bluffing you ;-) </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73738 Sun, 10 Jun 2012 12:06:50 +0000 freewhwheelin 73738@http://citycyclingedinburgh.info/bbpress/ <p>Nope sorry, word of mouth info. Dad of an ex SAS bloke, who is a RN trained engineer (submarines)who has a "valve gear" business, was telling me. The idea is to helicopter in these 4x4 and also motorcycles , close to target, then silent in and out on these compressed air vehicles. The helos can recharge the vehicles in transit apparently, presume these are chinooks, if land rovers are involved. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73734 Sun, 10 Jun 2012 10:53:54 +0000 Smudge 73734@http://citycyclingedinburgh.info/bbpress/ <p>@freewheelin, got a linky for that info? I'd be interested to read more :) </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73698 Sat, 09 Jun 2012 19:49:26 +0000 freewhwheelin 73698@http://citycyclingedinburgh.info/bbpress/ <p>This tech is used by the SAS for their vehicles, virtually silent. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73693 Sat, 09 Jun 2012 19:02:54 +0000 Uberuce 73693@http://citycyclingedinburgh.info/bbpress/ <p>I've pondered whether a bike frame could have an integrated air tank, presumably in the seatstays, for regenerative braking. The heat given off when inflating tyres suggests it's not worth the weight, though. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73689 Sat, 09 Jun 2012 17:13:39 +0000 Smudge 73689@http://citycyclingedinburgh.info/bbpress/ <p>Sounds very interesting, compressed air tanks are pretty safe (especially compared with IC engines!), after all, most HGV's and buses have had three or more tanks underneath for the brakes for years, divers have been transporting cylinders for years and I have not heard of many incidents... (I know of the odd filling accident, but they are *very* rare and normally involve operator stupidity).<br /> Most dive cylinders are rated for 232 Bar, you can get 300 bar cylinders but the increase in gas stored does not normally justify the increased weight required for cylinder strength. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73683 Sat, 09 Jun 2012 15:42:26 +0000 kaputnik 73683@http://citycyclingedinburgh.info/bbpress/ <p>Interesting* history of compressed air locomotives <a href="http://www.douglas-self.com/MUSEUM/LOCOLOCO/airloco/airloco.htm">here</a>, including diagram of a turn of the century triple-expansion "Porter Engine" with various compression, expansion and heat-transfer stages that sounds a lot like the above technology.</p> <p>* = for people interested in such things! </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73653 Sat, 09 Jun 2012 00:56:35 +0000 kaputnik 73653@http://citycyclingedinburgh.info/bbpress/ <p>Not a new technology at all - compressed air "fireless" locomotives have been used in mining for about 150 years. Only far less refined than the above concept, effectively a huge tank of air on wheels with some pistons and cranks to translate pressure into rotary motion.</p> <p>If you can make it work, compressed air is probably a lot better than directly burning fossil fuels for powering a vehicle, but it's still a pretty wasteful way of turning energy into motion, as you have to first compress the air somehow (electricity most likely) which is an inefficient process to some degree and then convert that into rotary motion, again not a wholly efficient process.</p> <p>I'm sure the ability to built very lightweight and strong vehicles now will help improve performance somewhat over the riveted iron mining locos. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73643 Fri, 08 Jun 2012 21:42:23 +0000 alibali 73643@http://citycyclingedinburgh.info/bbpress/ <p>Oh, and Airzound(sp) horns wil be fitted, of course! </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73642 Fri, 08 Jun 2012 21:41:31 +0000 alibali 73642@http://citycyclingedinburgh.info/bbpress/ <p>..and how big a bang will the tank make when damaged in a crash?</p> <p>If I remember correctly 300bar is the pressure at 3000m depth in sea water.<br /> Even a small enclosure for that depth is pretty heavy even if it's made of composites.<br /> As a result, again from memory, the energy density is about the same as lead-acid batteries.<br /> So 300km would be pretty impressive, but I suspect a very large tank and slow progress would be the order of the day.</p> <p>On the positive side, re-charge should be pretty fast assuming a storage tank at the side of the road. In case of emergency, the driver could always join in the helmet debate for a source of hot air... </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73640 Fri, 08 Jun 2012 20:57:54 +0000 chdot 73640@http://citycyclingedinburgh.info/bbpress/ <p>Sounds too good to be true...</p> <p>How big will the compresses air tank need to be? </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=7018#post-73639 Fri, 08 Jun 2012 20:53:57 +0000 LaidBack 73639@http://citycyclingedinburgh.info/bbpress/ <p>May have been covered elsewhere - don't watch all the gadget shows so sorry if old news. Release I've been given for news pages of next RSGS Geographer mag. </p> <p><ul>With fuel prices soaring, Tata Motors is set to launch MiniCAT, a car that runs on compressed air, developed by Formula One engineer Guy Nigre in Luxembourg for MDI. Unlike traditional petrol and diesel engines, the MDI technology doesn’t use any form of internal combustion. Instead, it involves four steps:<br /> 1<br /> air stored at around 300 bar is used to push the pistons (each requiring only 30 bar of pressure);<br /> 2<br /> heating expands the air to a factor of three to five times which is then injected on to the smaller piston, achieving a pressure which is twice as effective as a traditional internal combustion engine;<br /> 3<br /> the MDI active chamber, consisting of two pistons per modular engine head, then doubles the energy efficiency;<br /> 4<br /> ‘cool combustion’ – the sudden cooling of air means that low-grade heat generation can be stored and used to recharge the compressed air storage.<br /> Reports suggest that Tata will launch MiniCAT in India at the end of 2012, with an estimated price tag of Rs 6-700,000 (c£7-8,000). The car apparently has a travelling distance of 300km per tank, with a maximum speed of 105km/hr, and each refill of compressed air will cost Rs 100 (c£1.16) – cheap driving with zero emissions.<br /> </ul></p> <p>Energy to produce compressed air may come from coal in India but elsewhere it could be renewable....</p> <p><em>So we could have traffic jams of electric, hybrid and air powered vehicles in future...</em> </p>