What is a TON-MILE? Considerations of FUEL EFFICIENCY!

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The TON-MILE is a measure of efficiency for a means of transportation. People in the business of Transport invented the concept of TON-MILE. By far, in terms of TON-MILES, electric-diesel trains get the most TON-MILES from a gallon of fuel. Next would be 18 wheelers, though they are not close to as eficient as trains. Last would be your gasoline powered car and it is not even close to 18 wheelers. Let's do some calculations for 18 wheelers and cars. A typical 18 wheeler today might get 5.5 miles per gallon while grossing 40 tons. 40 times 5.5 = 220 TON-MILES. A typical auto might get 25 miles per gallon while grossing 2 tons. 2 times 25 = 50 TON-MILES. The 18 wheeler is more than 4 times as efficient as the car. That is pretty darn good. Is it possible to increase the TON-MILE rating of the car to closer to that of the 18 wheeler? Sure, you bet it is. Let's look at the differences between cars and 18 wheelers and what factors it is that make the TON-MILE difference. 18 wheelers use low rpm long stroke high torque engines with heavy duty transmissions and high speed rear end ratios. Cars utilize high rpm short stroke lower torque (compared to 18 wheelers) engines that do not require as heavy duty of a transmission (lower torque) and a slower speed rear end. These differences are very much what accounts for the differences in TON-MILE ratings for the 2 kinds of vehicals. So, if some of the characteristics of the 18 wheeler were incorporated into the car, would the car get better mileage? YES! But there are practical considerations that prevent the car from getting the 220 TON-MILES of the 18 wheeler. Afterall, if a 2 ton car was rated at 220 TON-MILES, it would get 110 miles per gallon! That is not going to happen because we lose the economy of scale advantage of the larger 18 wheeler when downsizing and long stroke engines just can not accelerate worth diddly. Who wants to drive a car that accelerates from a stop light no faster than an 18 wheeler? That's right, no one! So, could we adapt some of the advantages of the 18 wheeler until acceleration is too adversly affected and still gain fuel economy? YES. We know it can be done. It has been done. Many years ago, an inventor took a Perkins maritime diesel engine ( a long stroke, low rpm diesel), mated it to a modified transmission and a high speed rear end and did something marvelous! He got 60 mpg in the city! Sounds absurd, but wait a second. If the car weighed 2 tons that would be 2 times 60 = 120 TON-MILES. This is still only 1/2 the efficiency of the 18 wheeler. This means 60 miles per gallon using some of the efficency advantages of 18 wheelers, but not all of them, certainly could be possible. So, why can't you buy such a car today? Unfortunately, the Perkins powered car was no cleaner in its emmissions than a truck. Remember, it used as close as was possible to truck characteristics to achieve its greater efficiency. It is not surprising it was as dirty as a truck. Cars have to meet a higher standard to this car was banned from sale in the USA. That's the bad news. The good news is that diesel technology today is much improved and cleaner than ever. Someone soon should try this concept out again and get it to work cleanly enough. Why do you think no one has done this yet? Do you think the EPA only ruled against the Perkins powered car because it was a private individual and not one of the big 3 automakers who invented it? Do you think big oil had any possible role in making sure the EPA helped squash this threat to their bottom line? Any other thoughts or comments about the possibility of a high tech small diesel car?