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« on: December 20, 2007, 04:30:06 PM »
The main reason that diesel in the winter goes up is not because of the changeover in refineries(plays a small part) but because of pure and plain science. When they refine oil the is so much propane, so much gasoline, so much kerosene, so much diesel, so much bunker oil, and so much asphalt that comes out per gallon of crude. The companies can change the ratios slightly but not by much. When Caterpillar brought out there diesel engine tractors in the 1930's they didn't sell it for the fuel economy in their sales brochures. They sold it cause diesel was dirt cheap. Because gasoline was the standard fuel, diesel was a byproduct, very few used it. Same with kerosene. As trucks, trains, boats,jets,and home heat has switched over to these cheap fuels, then it became more than a byproduct into a main product. Propane exploded in popularity in the 50's because again, it was a waste product that most refineries just flared off but it's popularity have brought it to a main product status. As has natural gas that is extracted in the oil wells, landfills, and coal mines.
In the winter with heating needs rising, transportation and heating compete for a finite supply(refinery capacity, which hasn't grown in this country in years because of environmental laws make it near impossible to do so.) Diesel is not that much more efficient than gas engines when you measure pounds of fuel burned per hp.(All oil base fuel have very close btu's per pound measurements. The constellation engines exceeded the fuel efficiency of many diesels in their day and is close to many modern diesels. Large ground transportation (class 4-8 trucks and large equipment) gas engines did not receive any research and development and I am convinced that with turbos,turbo compounding, multiple spark plugs, modern fuel injection/computer ignition, overhead valves, that these large engines would have reaped the same lbs per hp that their diesel counterparts and light vehicle (gas and diesel) engines get.
Everyone is so engrossed with MPG that they don't look at the true picture of MPD miles per dollar or miles per Btu. Do the math, whether comparing a 3/4 ton gas and diesel pickups, or a efficient gas car to a diesel or hybrid counterpart, the gas engine will cost less in the total lifespan and in btu's, and that is comparing diesel when it was 10 cents cheaper than gas, not more expensive like it is now. (If you can regularly use waste oil then this doesn't compare,at least in MPD, but most can't)