Winson-Talk

Diesel vs Petrol

I gonna write about BMW once again. Today on the road I saw a BMW 530d. During then I was wondering why does people buy a 530d instead of a 530i. I always think that fuel efficiency for petrol is always better compare to diesel. Probably because all heavy duty vehicle back home uses diesel and it emits lots of carbon monoxide to the air. When I saw BMW 530d on the road , I was thinking that there are something on 530d that I will need to find out. First thing that i found out about 530d is the fuel consumption. It is more efficient compare to 530i. The next thing will be the huge torque advantage (369lb ft vs 221 lb ft) over 530i. I manage to find an article that wrote about the advantage of diesel over petrol and the technology used in making the fuel consumption more efficient.

Source : http://www.bmw.com.au/

As little as fifteen years ago, the diesel/petrol conundrum didn’t really exist. Diesels were slow, unrefined and fit only for taxis. It didn’t matter that they were cheaper to run than the petrol equivalent, because to stop at the black pump was to become a social pariah. But in the past few years, new technology has revolutionised the diesel engine so that they’re now a genuine and desirable alternative to petrol power.

The most significant technological breakthroughs concern the development of direct injection and common rail turbodiesel technology. Direct injection, as the name suggests, is a process by which the fuel is injected directly into the combustion chamber. The fuel supply can therefore be controlled more precisely, improving the efficiency of the combustion process. The latest common rail systems can also operate at a much higher pressure, further enhancing the detonation process. The result is more performance with improved fuel efficiency.

No less important has been the development of pre- or ‘pilot’ ignition systems. A tiny quantity of fuel is injected into the chamber and ignited before the primary combustion takes place. This minimises the harsh “knocking” or rattle sound traditionally associated with diesel powerplants. As a result, the latest diesel engines are now all-but as refined as their petrol equivalents.

The traditional image of diesel has been utterly transformed and it hasn’t taken drivers long to catch on. Executives who once sneered at the thought of a diesel car, are now revelling in the performance, refinement and fuel economy of the latest six and eight cylinder turbodiesel engines.

The petrol-powered BMW 530i and the diesel 530d cost similar money. The 530i has more power (258bhp vs 218bhp) but the diesel has a huge torque advantage (369lb ft vs 221 lb ft). In real world driving conditions, it’s the 535d that’s the faster, more engaging companion. And that’s before you consider the fuel savings – the 530d achieves an average of 40.9mpg, 8.8mpg more than the 530i. The diesel 5-series is not just more enjoyable to drive; it’s also cheaper to run.

This diesel-mania is even infesting the racing community. We’ve had diesel racers before – VW even sent a diesel van to the track – but they were no more than a token gesture, a marketing gimmick to appease the do-gooders. But now Peugeot is committed to building a diesel-powered Le Mans racer and Audi might well follow suit. They reckon they can achieve performance and economy, which in a 24 hours race is crucial.

Some commentators have suggested that we’re entering the age of the diesel, but such proclamations might be premature. Much of the technology that’s being used to such fine effect in modern turbodiesels is also beginning to filter into petrol engines. The Volkswagen group, for example, already offers a range of direct injection petrol engines that offer improved fuel economy and lower exhaust emissions. Audi’s Le Mans winning R8 was powered by a direct injection petrol engine, and a road-going derivative is employed to fine effect in the Volkswagen Golf GTi.

Sports car manufacturers will continue to favour petrol over diesel power. Petrol engines tend to weigh less than the diesel equivalent – an important consideration in a high performance car – and their free revving nature makes them more fun to drive. Many sports car drivers also continue to prefer the sonorous roar of a performance petrol engine to the more muted, deep bass mutterings of a diesel. Don’t expect to see a diesel-engined Ferrari rumbling down your high street anytime soon.

And while Le Mans may soon be populated by diesels, sprint racing will continue to be dominated by petrol power. A diesel-powered F1 car remains a preposterous suggestion, unless they change the rules. The point is not that diesel is about to replace petrol, but that for the first time we have a genuine choice. That can only be a good thing.

Source : http://www.castrol.com/

January 27, 2008 - Posted by winsonlee | Cars