One of the biggest decisions car buyers have to make long before looking at models or specs is whether to shop for diesel or petrol. Brendon Carpenter, Brand Marketing Manager at Suzuki South Africa, says this issue is debatable and hotly contested.Broadly speaking, the difference is that commercial cars, like bakkies, use diesel, but recreational cars use petrol - though there are many other distinctions between the two. For one, diesel cars are more expensive off the showroom floor, but are markedly more fuel efficient. Says the Automobile Association, “On average, diesel engines consume between 25% and 30% less fuel than their petrol counterparts.” However, the different fuel choices lead to a good many other differences too.
There used to be the negative perception that diesel cars were slower, smellier, noisier, and more expensive than petrol cars. Diesels have closed the gap significantly in these categories over the past decade.
There is a school of thought that maintains diesel engines are more harmful than previously believed, emitting toxic particles into the atmosphere.
However, modern diesel cars have highly efficient filters that capture these particles and a study by the University of Montreal showed petrol cars emitted up to 62 times more lung-damaging pollution in cold weather than their diesel counterparts.
Dr Patrick Hayes, of the University of Montreal, said: "Diesel has a bad reputation because you can see the pollution but it's actually the invisible pollution that comes from petrol cars that is worse.”
Engineering Explained goes into some of the more technical differences between the petrol and diesel below; specifically looking at how the different engines function. A quote from the video: “Gasoline engines attempt to keep the compression ratio so that the air-fuel mixture does not rise above the self-ignition temperature. Diesel engines, on the other hand, use higher compression ratios, leading to more torque and better fuel economy."