Far more cars drink at the black pump these days than when any of us first learned to drive. Diesel’s popularity as a fuel for cars has soared in recent years, pushed steadily upwards by its better economy and the pleasing driving characteristics of modern diesel-engined cars. In the UK’s new car sales charts, diesels outsell petrol models. Out there in the traffic, including both new cars and older vehicles, one in every three cars on UK roads is a diesel.
How that has changed over the past 30 or so years. When I was a young motoring writer, diesels were a bit of a novelty, bought for their better economy and not much else. Back then, driving a diesel car meant living with an unmistakable noisy clatter from under the bonnet, and having to tolerate a belch of sooty smoke from the exhaust on start-up. Well, once the engine had finally started, that is. Old diesel technology meant waiting impatiently for about 15 long seconds for the glow plugs to heat up before you could activate the engine. Who else remembers that?
Modern diesel technology is such a different experience. So much so, that the best diesels are now almost indistinguishable for noise from similar models fuelled by petrol. They no longer make the irksome clatter that instantly identified what was under the bonnet of the old cars. The once-characteristic smokiness has gone too. So the disadvantages of driving a diesel are history.
What now endears diesels to so many drivers is their better fuel economy and lower CO2, meaning lower bills for fuel, Vehicle Excise Duty and – for company car drivers – lower rate Benefit-in-Kind taxation. Petrol cars have recently been playing economy catch-up, and some of the best small-capacity new generation petrol engines are starting to close the mpg gap, but they have quite a way to go. Diesels are also time-savers, with an advantage in the distance they can go on a tank of fuel, meaning less frequent stops at filling stations.
There are down-sides, of course. A diesel car typically costs around £1,500 more up front to buy than the equivalent petrol model, although some of that is recouped by them holding their value better on the second-hand market. Diesel is also a bit dearer at the pumps than petrol, although the price of both has happily been coming down in recent weeks, and the bit extra you pay for a litre of diesel is more than made up by how much further you can go on it.
The net result of these various factors is that a driving a diesel makes the most sense if you are a higher-mileage driver, and so able to more quickly recoup the higher purchase cost through savings made on fuel costs and taxation liabilities. There is another reason, though, why diesels have gained such rapid popularity in recent times, and that is the driving characteristics. They are known for their good mid-range pull – technically, their torque – which gives them a zesty feel on the road.
Diesel still has a bit of a bad image as the dirtier fuel, and as a result has tended to be demonised in some quarters as a prime culprit for air pollution. Some local authorities in London have even opted to charge diesel-owning residents more for their street parking permits than those who drive petrol cars. The motor industry has rightly fought back, pointing out that today’s diesel car engines are the cleanest ever, and produce on average 20 per cent less CO2 than equivalent petrol models.
Cars makers should take some credit for their efforts in recent years to reduce CO2 output. The European Union set a target for emissions to average 130 g/km – grams of CO2 per kilometre driven – by 2015. In the UK, the average was down to 128.3 g/km by 2013, two years ahead of schedule.
The latest European car emissions regulations, known as Euro-6, demand a very high standard of cleanliness. An interesting fact quoted by the Society of Motor Manufacturers and Traders – the motor industry’s UK trade body – is that it would take 42 million Euro-6 compliant diesel cars to generate the same amount of nitrous oxides as just one UK coal-fired power station.
So anyone who drives a diesel, especially a very modern one, has no cause to feel guilty about it. The motor industry is fighting back and soundly debunking the demonising of diesel.