The Simple Difference Between Gasoline and Diesel Engines

IN a recent statement by the US Department of Energy, it was projected that by 2012, diesel vehicles could account for 4-7 per cent of the automotive market. When diesel gets 20-30 per cent better fuel economy than gasoline engines it makes sense. Could diesel work for you?

Gasoline engines use pistons to compress a mixture of petrol and air to 10-12 per cent of its original volume within cylinders. Then a high voltage current is sent to each of the cylinders’ spark plugs, which then ignites the petrol-air mixture.

Diesel engines, on the other hand, compress air to 4-5 per cent of its original volume. After compression, diesel fuel is injected into the cylinder. The heat of the compressed air ignites the fuel instantaneously.

The differences between the engines result in vehicles with different advantages and disadvantages. Read the following to see if diesel might work for you.

The Pros of Diesel

* Fuel Economy- Diesels give 20-30 per cent better fuel economy than their petrol counterparts. Sometimes their fuel economy is even better. Take, for example, the Volkswagon Jetta. The diesel version of this car produces 52 per cent better fuel economy than its fuel driven cousin.

* Life – Light-duty diesel engines, when properly maintained and treated well, will easily last over 300,000 miles (about 482,700 kilometres)

* Towing Capability – Diesels produce more drive force (torque) at lower engine speeds than gasoline engines resulting in great towing capability.

* Safety – Diesel fuel is less flammable than gasoline. Try it. A lit match thrown into a pot of petrol will ignite the fuel, but not so if it’s a pot of diesel.

The Cons of Diesel

* Emissions – Though much has been done to better the emissions of diesels they are still dirtier than petrol due to the sulphur content. However, the EPA just announced that US refineries are on target to supply ultra-low sulfur diesel by June 2006.

* Fuel, or more accurately, where to get it? – According to the Diesel Technology Forum only about 30 per cent of all retail service stations in the US sell diesel. (We’re lucky here, all petrol stations in Malaysia sell diesel; it’s not the best quality diesel, but it’ll do for now)

* Choice – Though the number is growing, there are a limited number of vehicles that run on diesel in the US, unlike Europe, where the popularity of diesel passenger cars is gaining ground every day.

* Expense – By and large, diesels are more expensive than petrol powered vehicles, although if you divide that cost over the life of the vehicle, diesel becomes cheaper. Locally, we have become rather spoilt for choice especially in terms of the pick-up truck market, where all are running on diesel, and most if not all are priced below RM100k.