MOTORNET: Diesel revolution

Diesel tends to conjure up images of black smoke and greasy petrol station pumps, not high performance and a 'clean green image.’But internationally, diesels are being embraced. Perhaps it's time New Zealand took a closer look....

It's an all too common sight. A heavily laden Jap import vanette labours up a steep incline, flat out at 50 km/h while a noxious black cloud of smoke covers everything in its wake.

There's not much fellow road users can do to retaliate. The most common response is to flick the ventilation switch to circulate and curse, usually something along the lines of 'bloody diesels, why don't they just ban them?'

It's a fact. A large proportion of the smelly and smoky vehicles on our roads are diesels. During a recent Auckland Regional Council campaign to 'Dob in a Smoky vehicle' a large number of the cars reported were diesels. Mostly, the excess smoke from these vehicles is the result of poor maintenance. Not surprising the number was so high considering that a poorly maintained diesel will continue to run, while its petrol counterpart won't.

But if you think that diesel is an outdated fuel best left to trucks and big four-wheel drives, then think again. There's a quiet revolution taking place, and one that it would be folly for Kiwi's to ignore.

Citroen and Peugeot diesel passenger cars have been making a good impression on our shores for a number of years, but even with these cars few think of 'performance' and 'diesel' in the same breath.

But that's changing - most noticeably with the decision by BMW New Zealand to introduce a new line-up of diesel products. It would seem the performance gap between petrol and diesel is narrowing fast, but not at the expense of fuel consumption. For example, BMW's new 530d is seven tenths of a second slower to 100 kays than the petrol 530i but it uses 32 percent less fuel, according to official European Union Figures. In the lighter 3 Series, BMW's 3.0 litre diesel delivers 0-100 km/ph in 7.8 seconds, a top speed of 225km/h - and an average fuel consumption of just 6.8L/100km. The fast yet frugal BMW is the world's first diesel sports sedan.

BMW 3 Series

BMW New Zealand says modern diesel engines - as used in Europe - are very clean, very economical, and every bit the equal of their petrol counterparts. New engine management technology enables greater control of fuelling and ignition in diesel engines meaning they are more efficient than the jap import 'commercial' diesels commonly seen in New Zealand.

It's no surprise then that BMW think they might be on to a winner by bringing them here, but the big question is, will they sell? BMW dealers say that where they offer a prospective buyer test drives in diesel and petrol equivalents - such as a 530d versus a 530i - there is a significant swing toward the diesel power plant.

BMW are not alone in seeing a market for luxury diesel products. Mercedes Benz already offer a diesel version of their impressive E class as well as a diesel M-class 4WD and A-class. By April of this year, expect to see the first examples of the new C-class in diesel form as well - surely a car to rival the BMW 3 series in the diesel sports stakes. It is rumoured that Mercedes Benz is even planning to offer a diesel version of its all-new SL roadster next year.

What's changed to suddenly make diesels such an attractive proposition? The simple answer is electronics and the environment. Huge advances in computer aided design and engineering over the past decade, combined with the advent of powerful and low cost computerised engine management systems have allowed engine designers to maximise the key benefit of the diesel - low fuel consumption - while minimising its downsides. Driving this are moves to reduce global carbon dioxide emissions in line with agreements reached at the 1997 UN Climate Change Conference in Kyoto - an agreement that New Zealand has agreed to ratify by 2002.

One of the big technology changes is called CDI, or Common-rail Direct Injection. The key to common rail technology is a pipe along the top of the engine, which contains fuel under extremely high pressure. Computer controlled 'intelligent' injectors act as taps that can open and close in microseconds. This provides the ability to control the amount, timing and pressure of the fuel injection to a degree of accuracy that was never previously possible. This accurate control optimises the combustion process, generates maximum efficiency and significantly reduces noise. It also enables particulate emissions to be minimised, to the extent that exhaust smoke is virtually unheard of. The result is increased performance, better fuel efficiency and reduced emissions.

If you like the sound of diesel but shudder at the price of German motorcars, don't be disheartened. Both Citroen and Peugeot offer common-rail technology on their medium and larger size cars with prices starting in the low to mid 30k mark.

New Look Citreon Xantia

Citroen New Zealand says having the technology available in the compact Citroen Xsara has brought modern diesels within reach of a much wider market. Citroen says that the increased torque output provides good acceleration without the need for gear changes or increased revs. Also, improved quietness and smoothness in the new Xsara is a further plus while the Common Rail diesel engine produces 21 percent less carbon dioxide than a petrol engined car of similar power output.

And while carmakers are happy to market these new vehicles as genuine performance alternatives, the really good news is big improvements for the environment. Internationally, carmakers are giving every indication that diesel will provide the interim 'green' solution before more advanced technology, such as the fuel cell, becomes available.

Of course, there are downsides. Diesels produce both particulates and NOx (oxides of nitrogen), both bad news for the environment. While emissions of NOx and particulates from diesels have been reduced 85 percent and direct injection diesels now account for 75 percent of passenger car diesel engines, further improvements are being made on the international market.

One problem for New Zealand is whether or not we can take advantage of these new developments. The technology may be here, but compared to Europe the quality of our diesel is poor, containing 0.3 percent sulphur – or six times that of diesel sold in Europe. The new technology will rely on low-sulphur fuel to work, clearly an issue that New Zealand fuel companies need to look closely at.

Even so, the day when diesels outnumber petrol powered cars may be closer than you think. Diesels now account for a quarter of sales in Germany, one-third in Italy, 45 percent in France, and a massive 55 percent in Austria.

A new diesel car in the driveway anyone? Not as strange as it sounds….

- Up Coming Review: Subaru’s new WRX turns heads and sets hearts afire

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