Bring Back the Diesel Hybrids

Reader Contribution by Staff

Hybrids are great little cars and trucks. I know, I’ve been driving a Toyota Prius in the mountains of Colorado for over four years now. I’ve been amazed by the car. This car’s got serious pep, gets great gas mileage, and handles snow and ice extremely well (with a good set of snow tires). I can drive to western Colorado and back from my home in Evergreen, climbing two mountain passes in the process, and get 53 miles per gallon – if I drive at about 60 miles per hour!
I get even better mileage when driving 60 to 65 miles per hour back and forth from my home in Colorado to my educational center, The Evergreen Institute, in east-central Missouri. During my last trip, I got 55.7 miles per gallon!

Great as the gasoline-electric hybrid is, they could do a lot better. Fuel economy could be increased dramatically by using lighter weight, but equally strong, composites (that is, high-strength, high-tech plastics) to build much lighter, but extremely strong (crash worthy) bodies. Lowering the weight could dramatically boost their mileage, as any auto engineer who understands fuel economy will tell you.

Fuel economy could also be improved by replacing gas engines in hybrids with diesel engines. Although diesel engines cost more, they are significantly more efficient and more durable (longer-lasting) than gasoline internal combustion engines. They also require less maintenance, the savings from which also help to make up for the higher cost.

Interestingly, three major US auto manufacturers developed extremely fuel-efficient  diesel hybrids during the Clinton administration.  They achieved an amazing 70 to 80 miles per gallon! (See accompanying table.) To learn more about these vehicles, visit Autospeed

The French car manufacturer, PSA Peugeot Citroen, is currently developing two diesel-electric hybrid cars.

Diesel Hybrids

GM Precept

Ford Prodigy

DaimlerChrysler EXX3

Fuel Economy (mpg)





1.3 liter

3-cylinder diesel

1.2 liter

4-cylinder diesel

1.5 liter

3-cylinder diesel

Lightweight material




Coefficient of drag




Weight (pounds)





Nickel Metal Hydride or Lithium polymer

Nickel Metal Hydride

Nickel Metal Hydride

Accleration Time

(0 to 60)

11.5 seconds

12 seconds

11 seconds

If manufacturers combined diesel with strong, but lighter-weight bodies, the mileage could climb even more. It is not inconceivable that we could be driving cars and small trucks that get 100 to 150 miles per gallon or more on diesel!  If an owner were to fuel the car with biodiesel or straight vegetable oil, these cars would quickly climb to the top of the green car chart!

Personally, I’d love to see Detroit manufacture its three diesel hybrids – right now!  And then get cracking on lighter composite bodies made from chemicals derived from natural sources, for example, plastics made from corn. This would truly help us create an energy-efficient transportation system.