Internal combustion engines remain firmly in the spotlight, even as electric mobility advances at pace. For many drivers, the real dilemma is not electric versus conventional, but whether petrol or diesel is the smarter choice in today’s market.
Both fuels offer distinct advantages, and the decision is far from straightforward. Factors such as fuel consumption, environmental impact, maintenance costs and driving patterns all play a role in determining which option ultimately pays off.
Efficiency versus emissions
With the same amount of fuel, a diesel-powered car can typically travel almost twice the distance of a petrol equivalent. Diesel engines are more energy-efficient, losing less energy as heat and delivering more usable power per litre. On average, diesel engines achieve significantly higher efficiency than petrol engines, translating into lower fuel consumption and fewer refuelling stops.
Petrol, however, has a higher energy density but produces more emissions during combustion. From an environmental standpoint, diesel engines have faced intense scrutiny, particularly after the “Dieselgate” scandal that erupted in 2015. Diesel fuel was heavily criticised due to higher emissions of nitrogen oxides (NOx), which are especially harmful to respiratory health.
To address this, modern diesel vehicles are now equipped with particulate filters that dramatically reduce these emissions, improving their environmental performance compared to older models.
Market shifts after Dieselgate
Until 2015, nearly half of all passenger cars sold in Europe were equipped with small, fuel-efficient diesel engines. The fallout from Dieselgate, however, triggered a sharp decline in diesel sales, despite the fact that under certain conditions diesel technology could have remained dominant.
At the same time, automotive innovation has kept petrol engines firmly relevant. Most mainstream categories now offer hybrid models built around highly efficient petrol engines, often combining small-displacement turbocharged units with electric motors.
The hybrid factor
Modern hybrid systems have reshaped the petrol versus diesel debate. In mild driving conditions, hybrid petrol vehicles can operate in electric mode for short distances, significantly reducing fuel consumption. The result is quieter operation, fewer vibrations and a driving experience closer to that of a fully electric car.
Hybrid systems also exist for diesel engines, but these are typically found in larger passenger cars or commercial vehicles. While exceptionally efficient, they tend to be expensive, limiting their appeal to niche segments of the market.
When does diesel actually pay off?
Most experts agree that the choice between petrol and diesel should be based primarily on usage. Diesel versions are usually more expensive to buy, and they only make financial sense if a driver covers more than 20,000 kilometres per year, with a significant proportion of that mileage coming from long-distance or motorway driving.
This threshold is considered the point at which the lower fuel consumption of diesel offsets the higher purchase price. That calculation, however, has become increasingly challenging as diesel prices have risen in recent years and now sit closer to petrol prices.
Maintenance and resale value
Petrol engines generally have lower maintenance costs, a factor that weighs heavily for many buyers. In addition, the steady decline in demand for diesel vehicles has begun to affect their resale value in the used-car market, making depreciation another point to consider before committing to diesel.
The bottom line
Diesel still offers superior efficiency for high-mileage drivers, while petrol, especially in hybrid form, is proving more adaptable, quieter and increasingly economical for everyday use. As fuel prices converge and technology evolves, the “right” choice depends less on the engine itself and more on how, where and how often the car will be driven.
Source: carandmotor.gr