diesel cars

today's economy motorist can't afford to ignore the diesel alternative. jonathan crouch charts the rise of the diesel car

diesel cars

The increasing popularity of the diesel-engined car in the UK has been truly remarkable. In 1983, just 24,486 took to the road - a mere 1.37 per cent of all new car registrations. A decade later, the figure had risen to 340,472, a total which itself was more than twice the level of sales two years previously. Today, diesel is an alternative that no new car buyer can ignore.

There are several reasons for this surge in popularity;

1. The design and performance of diesel engines has progressed well beyond those days when they were synonymous with unpleasant rattling noises, smoke and sluggish acceleration.

2. Diesel engines are more fuel-efficient than petrol and it is possible to cover up to 30 per cent more miles on a gallon of fuel.

3. Diesel engines are more durable and reliable, often running 150,000 miles or more without major overhaul.

4. Because of their economy (less CO2) and because of their more complete combustion, they are less polluting in many respects, than petrol engines. To meet present regulations, they do not need catalytic converters - though many now have them.

Obviously, such features appeal to operators of large business fleets. Extra mpg and slightly cheaper fuel alone can save many thousands of pounds on a large fleet. The savings also help to compensate for the higher costs of purchasing diesel vehicles and the more frequent servicing requirements.

The diesel engine first appeared commercially about 100 years ago. In Britain, it now powers virtually all heavy trucks, buses and coaches as well as many vans. Its popularity is particularly reinforced with urban delivery work, as fuel economy is far superior in stop-start usage.

Although diesel engines meet the emissions limits currently applied without the need for exhaust after-treatment, oxidising catalysts and use of lower-sulphur fuels will be increasingly necessary as emission laws are tightened. This will further reduce hydrocarbon and carbon monoxide levels although oxides of nitrogen require treatment which is, at present, the subject of much research.

Catalytic converters are already being fitted to diesel engines by some manufacturers and oxides of nitrogen can, in part, be controlled with the use of exhaust gas recirculation, which may be electronically controlled.

Particulate emissions, arising from the diesel's method of combustion, will be substantially reduced by greater combustion efficiency, but lower sulphur content in fuel will probably feature among improvements in the future.

A few years ago, diesel engines received something of a bad press as the result of various government-sponsored reports. Some health hazards were alleged which were, in the view of the motor industry and some sectors of the medical profession, largely unsubstantiated.

The reports almost totally failed to acknowledge the considerable research and development work which had been carried out in this field and which is continuing. They also singled out diesel cars for vilification without pointing out that the emissions from this source are barely significant when compared with the output of diesel-engined commercial vehicles which had been on the roads for many years.

In Germany, which tends to be far more sensitive to green issues than the UK - similar concerns about diesels resulted in extensive investigation which, in the end, removed the blame, although the scare did, for a short time, undermine diesel's popularity there.

Diesel The History

When the steamer `Dresden` completed its overnight voyage from Antwerp to Harwich on September 30th 1913, there was consternation on board. A passenger was missing - and the circumstances were mighty mysterious.

The 53-year-old traveller had last been seen the night prior to the ship's arrival taking a solitary stroll on deck before retiring to his cabin. Inspection of his berth revealed that the bed had not been slept in and a high-spirited dinner with colleagues just before his disappearance suggested that suicide was improbable.

Eleven days went by before the mortal remains of the passenger concerned were found floating off the Belgian coast. He was identified as one Dr Rudolf Christian Karl Diesel. It was a mystery tailor-made for Hercule Poirot and in the absence of the great fictional detective, has never been solved.

Fortunately, the facts surrounding the life of Doctor Diesel are a great deal easier to establish than those of his death. He remains the only engine designer whose name has become a household word and like all great inventors, he gave everything to the task of perfecting his brainchild.

In common with most great discoveries, the principle behind the diesel engine seems astonishingly simple when you think about it. Based around the idea that compressing air generates heat - as anyone who has ever used a bicycle pump will testify - the concept was first realised when twelve year old Rudolph was a pupil at The School of Industry in his home town of Augsburg, Germany.

He and a few classmates got hold of an airtight glass cylinder connected to a hand-operated piston and watched wide-eyed as a few brisk pumps made a pile of timber placed the other side of it glow and smoulder as if by magic. From that point, it was necessary only to introduce finely divided fuel into this hot compressed air for combustion to take place so that the heat became usable as energy.

It was not until he had reached maturity however in 1893, that a patent was finally granted on his invention. Just a few months later, the world's first diesel engine, a ten foot high single cylinder monster, spluttered into life at the Maschinenfabrik factory in Augsburg. The good doctor was reportedly so overcome that he went home, embraced his wife and burst into tears.