Posted by b4pw [108.162.216.169] on Sunday, February 19, 2017 at 09:53:10 :
I havent had time to be on here the last few days. Most times I don't like commenting on here because everyone seems to be rocket scientists. I'm sorry I have this attitude but when you're a mechanic for a living, you use common sense, you don't go 5 miles out of town to get to the gas station around the block. That being said, I am a mechanic for a fleet of about 300 tractors, trailers and straight trucks.I also have started my own shop on the side. Out of those vehicles, we have about 30 tractors running CNG. 12 are what are considered "dedicated" and the rest are "dual fuel" conversions, with one "bifuel" F250. Dedicated means just that, solely CNG, IE: cummins 9 liter with spark plugs. Dual fuel is a diesel conversion that still needs diesel fuel injected as the "spark". Bifuel is a gasoline engine, starts on gasoline then quickly switches to CNG. I have been trained on the Cummins fuel module and also a certified fuel system inspector. These systems, from the tank/mounting systems up to the regulator have to be inspected every 3 yrs or 36,000 miles. Sorry, i'm getting off track. What I would like to say is,I dont feel that its worth the money at a fleet standpoint. It costs roughly $30,000 to convert a brand new fuel system. The tractors will use, on average, 70 gal of diesel and maybe 20 gal of CNG on a good day. Some tractors the drivers dont fill the CNG for a couple of days. We had them on 8 straight trucks for a couple years but took them off because none of them used more than 40 gallons a week (CNG). If you spray too much CNG in, it WILL burn pistons. CNG ignites at 1200 degrees, I forget the air-fuel ratio right now, I think its 17:1. There is so much to tell about CNG that I could go on. In a nutshell, I personaly dont believe its worth it. I don't know how it would be in a personal DIESEL but believe in a gas engine it is worth it. Our price at our own fuel site was $2.14 gge, it has gone up but I dont know the price now. Again, I apologize for my comment at the beginning if it offends anyone. Roy
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