Walking around at the snowmobile expo in Jyväskylä, Finland yesterday, a Lynx Yeti 1300 caught my eye. Great work sled, yes, but what I really was looking at were the 2 scuba tank type bottles peeking out from under the seat. This wasn't NOS, I was sure. Later on I had the privilidge to talk to Gasum's Arto Riikonen, the man with answers to my questions. What I was looking at, as it happened, was a methane powered sled! This was apparently one of four prototypes in Finland. The tanks capable of storing 5 kg of methane at 200 bar, the equivalent of 7.6 liters of gasoline, the sled had a range of 50-60km on gas. Being bi-fuel equipped, the full stock range on gasoline was also available on demand, the only drawback being the extra 35 kg brought on by the tanks. It doesn't sound like much, but it is when you're stuck by yourself in deep powder. Targeted at ski resorts and grooming trails for the pickiest of cross country skiers, this wasn't a practical snowmobile for personal use, but one that was clean burning and wouldn't cause problems in crowds with it's emissions. Having been around traditional carburated 2-stroke sleds my whole life, I can hardly understand anyone complaining about the injected 4-stroke V-2 engine on the Yeti on gasoline, even if it has no catalytic converter, but a great idea never the less. Although intended for natural gas, I can imagine most of y'all thinking, as was I, can anyone say "biogas?" The technical stuff : high pressure gas was routed to an engine coolant heated pressure regulator, pressure dropped to 2.5 bar for the injectors, controlled by the ECU. I didn't get an answer to wether it uses the stock ECU or if there's another black box for use with methane, but I'll follow up on it. The principle is the same as EFI, the injectors are different to be suitable for gas, but being a stoichiometric burn engine on methane, the lambda sensor was common and its use identical, so I see no problems with just routing the injector signal to whichever fuel is in use, just adjust the injector or pressure. The engine is started and warmed up on gasoline to provide warm coolant for vaporization, which could otherwise be problematic in subzero temperatures (when else do you operate snowmobiles?), unless it's preheated by grid power like cars in wintertime. In general about methane use, apparently ignition can be a problem, since the catalytic converter can only take so much misfire in operation and methane is harder to light. This requires higher voltage ignition which takes its toll on spark plugs, which either need to be changed often or switched to iridium spark plugs. Not the NGK's that cost 5-10 times as much, but apparently about 50 times as much. This isn't a problem with non-catalyzed exhaust, like the snowmobile. Methane does apparently require a catalytic converter to meet the same emission requirements as modern gasoline engines, it's still not THAT clean, so for new cars, it's a must. Cylinder head temperatures also rise due to lost burning efficiency, which lead to faster warm up time and a greater chance of overheat in hot weather. Although generally not a problem in snowmobiles, natural gas busses take this into consideration with larger radiators. It is possible to raise compression to take advantage of methane's higher octane rating, but this eliminates the possibility for use with gasoline. He mentioned that the methane needs to be at least 95% pure for compression to 200+ bar, which wouldn't be a problem for a biogas home brewer bottling it at lower pressure, but complicates its commercial use. In snowmobile use high pressure is a must because of limited storage space and way high fuel consumption. The absence of CNG fuel stations out in the boonies up north really does turn one back to liquid fuels in personal use. I'm planning on bugging this guy some more via e-mail, and he offered to send some more material.
www.gasum.com is the company behind the prototype http://www.brp.com/en/Products/Lynx/Showroom/Yetiv1300.htm the sled it was made from _______________________________________________ Biofuel mailing list Biofuel@sustainablelists.org http://sustainablelists.org/mailman/listinfo/biofuel_sustainablelists.org Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Search the combined Biofuel and Biofuels-biz list archives (50,000 messages): http://www.mail-archive.com/biofuel@sustainablelists.org/
