Question of the Week: Are diesel hybrids a good choice?
Fri, 01 Nov 2024
Dear Honest John,
"I know that if you drive less that 10000 miles a year, a diesel isn't the right choice. What about a diesel hybrid engine? Does that have a minimum recommendation?"
- MS
Dear MS,
The basis for the assumption that a diesel car is less suitable than a petrol car for mileages under 10,000 per year is that the savings from the better economy of a diesel are insufficient to offset the extra cost of a diesel car compared to petrol and the higher cost of the fuel. The more miles you travel, the greater the benefit of the better fuel consumption.
The other point to consider is that diesel vehicles of all kinds have a DPF, which requires regular longer journeys to ensure it can regenerate effectively. If your 10,000 miles a year involves many short journeys, a petrol hybrid will likely be a better choice.
With a diesel hybrid it depends what you are comparing it with. Hybrids are, generally speaking, more expensive than both petrol and diesel cars, although there are few models where you would have a choice of petrol, diesel and hybrid, and none where you can choose between diesel and petrol hybrid.
Diesel hybrids are also far less common than petrol hybrids - there are only a handful of models you can buy from manufacturers such as Mercedes-Benz, BMW, Jaguar and Land Rover. Partly this is because of expense - petrol engines are cheaper to make than diesels, and hybrids are more expensive to build than non-hybrids, so combining the two means high prices for customers.
In addition, there's an argument that a petrol engine and an electric motor complement each other better than diesel and electric. E-motors work best a low speeds with generous torque from zero revs, while the petrol engine fills in a higher speeds. Diesels tend to major on torque rather than power which is more similar to electric motors, so the benefits are potentially less significant.
In short, the benefits of a diesel hybrid versus a petrol hybrid, regular petrol and diesel are small, and unlikely to be worthwhile unless you are covering over 10,000 miles.
Do diesel hybrids have DPF problems?
