Friday, December 5, 2008

Petrol or diesel: What fuels your drive?

Before anything else, if you have only tried driving petrol powered vehicles and not a diesel or vice versa, you should try driving both first – and no, not simultaneously. And if it has been a while since you’ve driven one or the other, it would be wise to try again with the more current models; the technological changes might surprise you.

The choice between petrol and diesel always boils down to one’s personal preference yet very few people are undecided about the issue. Try asking your friend about which engine type is better and he’ll likely give you a very passionate opinion rather than a straightforward answer. If you want the objective truth, let me give you the facts so that you can decide for yourself.

Fuel Economy

With the rising oil prices, fuel economy is a crucial factor in choosing your next car. Diesel engines are inherently more fuel efficient and can save you money in the long run.

They are more efficient than petrol (per liter of fuel burned) because diesel fuel has a higher energy density. When engines run while the vehicle is at idle, a diesel engine will only consume about one third of what a petrol engine will. Diesel fuel is also generally priced lower than petrol, at least right now. All these potential savings from a diesel unit could substantially accumulate over the years, especially if you plan to rack up a lot of kilometers.

Maintenance Cost

In the short term, regular maintenance for diesel units will cost more as they need to be serviced more often, they have a larger volume of oil in the engine, and diesel replacement parts can become quite expensive.

On the other hand, diesel engines become cost effective in the long term because of their excellent durability. An average petrol unit can only run for about 200,000 kilometers before needing a major overhaul while an average diesel engine can go three times further – and while regularly pulling heavier loads.

Noise and Vibration

Engine noise reduction technology has rapidly improved during the last decade. But the fact remains that diesel engines are relatively louder and shakier than their petrol counterparts. The difference becomes more noticeable when the vehicle is at idle or when it is accelerating from low speeds.

Emissions

If you want to know which type of fuel gives off more pollution, I’m afraid the answer is too long and complicated for me to coherently address in this article. Suffice it to say that only diesel engines emit significant amounts of Nitrous Oxide (NOx) and soot. While both diesel and petrol emit Carbon Dioxide (CO2), diesel emits slightly less for the same amount of energy output.

Speed and Power

Let’s not go down the long and winding “horsepower vs. torque” road. The more important thing to know is that diesel engines can always beat petrol when it comes to towing capacity and pulling force because they generally produce more torque. On the other hand, petrol engines can give you even more speed and acceleration while at high speeds because of the higher horsepower and RPM they can attain.

So, what’s the verdict?

Still undecided? You might want to consider the following: what you plan to use the vehicle for and what type of environment you are living in.

If you want a car that is quick and quiet for your everyday driving in paved and narrow roads, if you don’t plan to ferry a lot of people and haul heavy stuff, and if you plan to replace your vehicle before it reaches the 200,000 kilometer mark – get a petrol compact or sedan.

If you live in are where steep climbs and rough roads are the norm, if you are looking for a vehicle which is ideal for towing or hauling heavy loads, if you plan to take on a lot of passengers everyday, if you plan to get a lot of good mileage and long term fuel economy – get a diesel truck, van or SUV.

by: Edon Canada
AutoTerminal.com

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