The average fuel economy of the US vehicle fleet is not very good. Sure, this is because until recently oil and gasoline were cheap like water. Now that is starting to change. With countries like China and India beginning to reach high standards of living the demand on global resources is set to soar. And at the same time, some of those resources are going past their peak, like for example oil. The result is that in the future fuel economy will be something to care about.
Look at this abstract and you can see that in the whole history of the automobile in the US, the fuel economy has been poor. I didn't buy the paper, so I am going to quote only the abstract below, but it gets the idea across. Also note that I converted the MPG numbers in the quote to GPHM, so it is not a straight quote.
This article documents and analyzes the changes in fuel efficiency of vehicles on US roads between 1923 and 2006. Information about distances driven and fuel consumed was used to calculate the on-the-road fuel efficiency of the overall fleet and of different classes of vehicles. The overall fleet fuel efficiency decreased from 7.14 GPHM in 1923 to 8.40 GPHM in 1973. Starting in 1974, efficiency increased rapidly to 5.92 GPHM in 1991. Thereafter, improvements have been small, with efficiency reaching 5.81 GPHM in 2006.
So the vehicle fleet considered en masse went from 7.14 gallons per hundred miles in 1923 down to 5.81 gallons per hundred miles in 2006. That is an improvement, but it doesn't seem like much considering that we are talking about 83 years. Of course in that time we added more weight to our vehicles, drove them at higher speeds and added all kinds of powered comforts like air conditioning. In fact, most of the technical advances in cars and trucks are in these other areas because fuel economy was never a concern.
But what if fuel economy had been a concern? Could Detroit have followed a different path and left us today with better fuel economy? I think the answer is yes, and so do other people. Here is a comment giving a list of changes Detroit could supposedly make to improve fuel economy by 40%. The list is copied here:
- Miller cycle
- variable valve timing
- variable displacement
- turbo-compounding
- NuVinci-style CV transmission
- lighter construction with composites and lighter metals
- smaller vehicles, designed for maximum utility
The next 7 posts here on Save on Gas will look at each of these technologies to see what advantages it could provide and speculate on why it has not been widely deployed by Detroit.
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