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Alternative Fuels for Motor Vehicles

Diesel

It may seem strange to put diesel as one of the fuels of the future but there are advantages to using diesel oil as an automotive fuel and it would seem sensible to extend the use of diesel in the future because of those advantages.

Generally diesel engines are more efficient in their use of fuel than petrol (gasoline) engines. The compression ratio within the engine block is much higher and you will get more power out of the fuel. Diesel fuel itself has a higher energy content than gasoline.

• Diesel engines are heavier than gasoline engines. They need to be to accept the higher compression forces inherent in the design. They tend also to have a longer life. In general the fuel consumption for a diesel-engined car is about 20% better, even allowing for the heavier engine.
• The torque, generally understood as the pulling power from low speeds, is greater for diesel-engined automobiles than for gasoline-powered units.
• The emissions from diesels are a bigger problem. The popular image of a dirty, black exhaust from a diesel is no longer true but this has produced a mental acceptance of diesel as a "dirty" engine. Nonetheless the modern, direct injected, diesel engine is a much cleaner and more efficient power unit than the public gives it credit for. Again, generalising, the level of Carbon monoxide in the exhaust is considerably lower than for a petrol-engined car. However, they can produce black soot (or more specifically "Diesel particulate matter") from their exhaust, which consists of unburned carbon compounds.
• In the United States diesel is not as popular in passenger vehicles as in Europe. Such cars have been traditionally perceived as heavier, noisier, having performance characteristics which make them slower to accelerate, sootier, and of being more expensive than equivalent gasoline vehicles. This image does not reflect recent designs, especially where the very high low-rev torque of modern diesels is concerned - which have characteristics similar to the big V8 gasoline engines popular in the US.
• European governments tend to favour diesel engines in taxation policy because of diesel's superior Fuel efficiency.
• In addition, diesel fuel used in North America still has higher sulphur content than the fuel used in Europe, effectively limiting diesel use to industrial vehicles. Most Diesel sold at the pump in Europe is "Very Low Sulphur" Diesel.

In summary then, having better fuel consumption and lower Carbon monoxide emissions and, once Low sulphur fuel is more widely available in the United States, then Diesel would be a better choice for fuelling the car of tomorrow.

There are however other contenders which must be considered.