Friday January 5, 2018
The development of the diesel road car has come a long way in a comparatively short space of time. Automotive engineers will tell you that one of the car industry’s crowning achievements in the past 20 years is to civilise the diesel engine to such a degree that it’s still Europe’s foremost engine of choice. But with the onset of increasingly tough emissions regulations, it’s on the brink of being outlawed from all major cities – a major problem if you own one.
It wasn’t always this way. Although the first diesel-engined road car was sold to the public in the 1930s, it was recognised as slower and more unrefined than the petrol alternative. The upside was simple – fuel consumption was far better, and these stronger engines were capable of covering huge mileages without overhaul. That made them great for commercial applications, as well as being perfect as taxis.
By the 1970s, diesels were beginning to make significant inroads into the passenger car market, with Volkswagen Golf Mk1 and Peugeot 305. At that time an average petrol-engined family car would last 100,000 miles and deliver 30mpg. Compare that with the diesel equivalent of 250,000 miles and 45mpg. But it was primarily in France and Germany where the growth was – and that was because diesel was cheaper.
It wasn’t until the late 1980s that diesel-powered cars started to take off in the UK. The arrival of the Citroen BX, Peugeot 405, Austin Montego and Audi 80 turbodiesels saw the performance and refinement gap significantly close. They were still capable of 50mpg and covering 200,000 miles without a rebuild, but now you didn’t have to wear ear defenders to drive them, or minutes waiting for their glow plugs to warm up.
Mass company car sales followed, and throughout the 1990s, diesel’s growth continued unabated in the UK, despite a number of environmental warnings about air-born particulates. By 2001, Global Warming was big news, and diesels were in a great position to capitalise on this. They were more efficient in their use of fuel, therefore they generated less CO2, and as such, attracted lower tax, now that it was calculated on emissions, rather than engine capacity.
Throughout the 2000s, more people bought diesels on the strength of their lower taxation and fuel costs. During this time, engineers were refining diesels to such an extent that despite the fuel’s inherent disadvantages, they’d achieved parity in power while maintaining lower fuel consumption.
Yes, they’d had to introduce new fuelling and anti-emissions systems, such as high-efficiency common-rail fuel pumps and diesel particulate filters to make that happen, but that was OK, wasn’t it? Well, it would have been had it not been for the fact that in order to eke out the power, diesel’s once-legendary robustness was also under threat. So much so, that petrol engines were beginning to look like a better option if you wanted to see out a six-figure mileage from your car.
But in the early 2010s, the political climate began to change. Taxation income from diesels was dropping, and there was increasing evidence of a degradation in air quality, especially in big cities. Then came Dieselgate – the scandal that revealed that Volkswagen had been cheating in emissions tests in order to get its high-power models though increasingly strict air quality regulations.
Almost overnight, the balance shifted, and governments across Europe pushed ever harder to introduce tough clean air legislation to get older cars out of city centres. Not just diesels, of course, but it was these cars that were taking the brunt of the blame. And as we look towards the 2020s, we can see that diesel sales are starting to drop, and buyer confidence in it is starting to wane.
Was diesel doomed to fail? No. But governments and legislators underestimated their growth in popularity and as such, were surprised by just how much of an impact they had on the environment. Carmakers did a fantastic job in making this inherently inferior fuel work as well as it did, and in the end, paid the price for making them too good. If anything, diesel has been a victim of its own success.