UK: Driving out the guilt - DIESEL CARS.

UK: Driving out the guilt - DIESEL CARS. - Both cost-effective and green, diesel is "the best form of personal transport there is, apart from a bicycle".

by Daniel Butler.
Last Updated: 31 Aug 2010

Both cost-effective and green, diesel is "the best form of personal transport there is, apart from a bicycle".

Motorists these days seem dismayingly unperturbed by the amount of pollution they cause. "The bulk of our clients take a very passive role towards the environment and in today's climate are more concerned with the economy rather than ecology," says Geoff Cobley, managing director of Fleet Management Services, based in Shrewsbury. "Most take the view that catalytic converters are as far as they need to go towards helping the environment."

This contrasts sharply with the enthusiasm for protecting the environmental that swept British industry at the end of the '80s. Then companies such as BOC, British Gas and IBM were keen to present themselves as "green". They introduced environmental audits and their projects were pollution conscious. But as companies today struggle against the recession, cost-cutting has taken priority and good intentions have gone by the board. However, it does not necessarily cost money to be environment friendly. On the contrary, there is one area where companies can actually save money and feel morally absolved: greening the company fleet and executives' cars is a way for a company to combine financial shrewdness with environmental virtue.

Green-minded companies or individual car owners have several options to choose from. Lead-free petrol is the most obvious choice. (The compulsory fitting of catalytic converters on all cars built after September 1992 will improve the effectiveness of this option.). Better still, they could decide on a smaller engine, or delay the replacement of fleets. With both of these options, however, companies are up against the human problem of what the company car actually means to many, if not most, of its drivers - status. All too often ambitious young executives view the make, model, engine size and performance of their vehicle as a statement of their value to their company. Indeed, to paraphrase a famous slogan - your car says more about you than money ever can.

The best solution, and one that is certainly financially as well as environmentally beneficial, is diesel-powered vehicles. "Any form of automotive transport has a negative environmental impact," says Vernon Jennings, a director at environmental consultants SustainAbility. "But a well-serviced diesel is probably the best form of personal transport there is apart from a bicycle."

John Gardiner, product affairs manager for Ford UK, elaborates, "Even a standard basic diesel engine, if well-maintained, is up to 30% cleaner than a conventional car fitted with a catalytic converter. The reason is that diesel is more efficient than petrol. It may emit about the same amount of gases per gallon of fuel, but if you are travelling further for that gallon then it is obviously less polluting."

At Citroen, public affairs director Matthew Sharp agrees: "You can't eradicate the environmental impact of a car, only minimise a car's effect and the best way to do that is by cutting fuel consumption to a minimum."

The fuel consumption of diesel engines is impressively low. At present the Citroen AX, which gives 116mpg, holds the record for the most fuel-economic production car in the world. Other Citroen models are similarly economical. Diesel engines are particularly good for urban use, since, with petrol, short-hop driving, combined with the use of a choke, reduces fuel efficiency to a minimum and raises polluting emissions to maximum levels. Furthermore, if a diesel engine is fitted with a turbocharger, efficiency can be increased by as much as 50%. Added to that, a catalytic converter, direct fuel injection, exhaust gas recirculation and inter-cooling all help reduce pollutants.

Sir Anthony Gill, chairman of Lucas Industries is a confirmed diesel enthusiast. He believes that they "offer one of the least difficult and quickest ways of reducing global emissions". His opinion is backed by the actions of the environment conscious Body Shop chain, which has an "all-diesel" company car policy. Nevertheless, unlike many other countries in Europe, Britain has been slow to buy into the technology for anything other than commercial vehicles. Diesel engines have been popular in Europe for a long time, thanks to a combination of lower price and high quality of fuel.

Admittedly, until recently, British diesel fuel was plagued by a high sulphur content and indifferent quality. Diesel is also thought to give low-performance and cause engines to belch smoke. Rupert Saunders, public relations manager for Peugeot, believes this image is misleading: "The dirty smoke you sometimes see coming out of the back of poorly-maintained diesels is soot and not actually environmentally damaging."

Another possible reason for British drivers' tardiness in switching to diesel is the lack of a more positive government stance. Many in the industry feel that much more could be done to encourage the consumer. Until recently taxation of engine sizes put diesels at a disadvantage - a 1.9-litre diesel, for example, has the bhp of a 1.6-litre petrol engine but would have been taxed at the rate for a 1.9 litre. This policy hit executive diesel models particularly hard, as most would fall into the over-two-litre category. This is now being phased out, with taxation to be based on price rather than engine size. But Gardiner still feels that the cards are stacked against the diesel: "There should be a greater differential between diesel and petrol, particularly unleaded fuel," he says. He adds that Ford would certainly welcome a well-thought out carbon tax which would help encourage customers to move into diesels.

Manufacturers meanwhile have put alot of effort into improving their diesel engines, while the oil companies have improved the quality of their fuel. Two years ago Rover had no non-commercial diesel vehicles. Now there is a diesel version of virtually every model it produces. BMW, who for years dismissed the feasibility of producing a luxury diesel for the UK market, is about to launch its first models: the 325 TD followed by the 325 TDS. A diesel version of the 5-series is also planned for later in the year. Investment in the appropriate technology has resulted in a markedly improved product according to Fleet Management's Cobley: "So many of the modern diesel engines are capable of high performance that the image of the dirty diesel has long gone and high performance models have taken their place. There are one or two diesels which are better performers than their petrol equivalents," he says. Lucas's Anthony Gill agrees: "Diesel's technological advance has been particularly rapid in the last 10 years. Performance of diesel vehicles is now excellent." This view is endorsed by Peugeot's Rupert Saunders: "We engineer and design our diesels with a view to making them as comfortable as a normal car. They may not be quite so quick off the mark, but for motorway driving they're every bit as good," he says.

Furthermore, there are signs, according to Cobley, that diesel is becoming fashionable among discerning drivers: "Most of the thrust towards diesel comes not from fleet operators but from drivers, some of whom are even beginning to see diesels as a status symbol in their own right."

At Peugeot a lot of marketing effort goes into persuading potential customers to test models for a day or so, "to give them a real idea of what they can do". This, says Saunders, is often enough to win over even the most prejudiced of drivers.

But what of the sceptical company accountants? According to Saunders they offer little resistance: "We point out that diesels are more economical in fuel and maintenance costs than petrol," he says. Indeed, as anyone who has looked at secondhand vehicles recently can confirm, diesels keep their value better. The car rental company, Hertz, calculated that a 10-car fleet of Peugeot 405 1.9 GLD diesels would, over three years, save £22,000 compared with its 1.6 petrol equivalent, the 405 1.6 GL; while a 10-car fleet of the diesel Rover 218 SLD would save over £9,000 versus the 216 SLi. SustainAbility's Vernon Jennings says, "The longevity of the engine is greater - 200,000 miles is not uncommon for taxis." If this means that, in the end, fewer engines are manufactured this is another environmental bonus.

People are beginning to realise the economic advantages, says Ford's Gardiner. This view is based on the dominance of diesel in the commercial market where 80% of the firm's sales are non-petrol. "Customers have realised that they need less servicing and are more fuel efficient," he says. While Peugeot's fleet sales rose by 6.6% in 1992, within this diesel sales rose by 77%.

Matthew Sharp at Citroen feels that the economic climate is actually helping the diesel market: "Motoring is getting more expensive and diesel is one of the best possible ways to reduce its cost."


Pollutants Petrol car with 3-way Diesel car

catalyst (grams/km) (g/km)

CO 2.7 1.0

HC+NOx 1.4 1.1

SO2 + particles very small 0.22

Total 4.1 2.3

Fuel consumption 115.0 83.0

Source: German Engine Manufacturers Association (VDA)


Cycle Diesel (g/km) Petrol (g/km)

*European urban drive, 1.45 2.43

(fully warmed up,

10.0km at 20oC)

*Complete US cold transitory 1.48 4.81

(from cold start,

conditions vary,

5.57 km at 20oC)

Non-standard cold urban, 3.53 36.42

2.5km at 25oC Non-standard

cold urban, 3.58 57.65

2.5km at 10oC

*Standard government cycles used in measuring and determining acceptable


Source: Lucas Industries.



1980 0.4

1981 0.7

1982 0.9

1983 1.4

1984 2.6

1985 3.6

1986 4.1

1987 4.6

1988 4.6

1989 5.4

1990 6.4

1991 8.8

1992 12.6

Source: Society of Motor Manufacturers and Traders


Maker Diesel Market

Total Market (12.6%) (100%)

Peugeot 28.2 8

Citroen 14.8 4

Rover 13.9 13

Ford 13.7 22

GM 13.0 17

Renault 4.8 5

VAG 3.1 5

Isuzu 1.8 -

Mercedes 1.4 -

Toyota 1.0 3

Source: Society of Motor Manufacturers and Traders.

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