When a diesel or gasoline engine is running, most of the fuel’s energy is converted not into movement, but into heat. This isn’t visible to the naked eye, but becomes clear if you look at the engine through a thermal camera: the camera shows how the engine literally glows with heat, while the nearby electric motor remains almost cold.
According to experts, diesel engines use about 40% of the fuel’s energy for movement, with the rest lost as heat. For gasoline engines, this figure is even lower — around 30%. By comparison, electric vehicles can convert up to 85% of incoming energy into motion. This explains why electric cars consume charge much more efficiently and require less energy to cover the same distance.
Heat instead of movement
Thermal imaging clearly shows: in a diesel car, the engine and exhaust system heat up quickly, and the cooling system has to constantly fight excess heat. Even when the engine is idling, fuel continues to burn, heating components and releasing heat into the environment. Electric motors work differently: they have fewer moving parts, almost no friction, and most of the heat is generated in the battery and power electronics — but only during heavy use or rapid charging.
In one of the popular videos using a FLIR camera, the difference between the two types of engines becomes especially obvious: the diesel engine literally blazes on the screen, while the electric car remains almost neutral in temperature. This not only illustrates the difference in efficiency, but also explains why electric vehicles require less maintenance—they have fewer parts subject to wear and overheating.
Practical choice
For the driver, this means not only saving energy, but also reducing maintenance costs. Electric vehicles do not need a complex cooling system, do not require regular oil and filter changes, and often have a longer lifespan due to fewer wearing components. However, electric cars also have their own limitations: their driving range is still lower than traditional models, and charging time remains an important factor when choosing.
Those choosing between different types of cars should consider not only fuel costs, but also how exactly energy is consumed. As russpain.com notes, comparisons of technical solutions and design approaches can also be seen in other models—for example, in the article about the differences between the Citroën C4 and Seat León.
What you need to know
The shift to electric propulsion is not just a trendy fad, but a technological breakthrough that is changing the way energy is used. Thermal imaging only confirms: most losses in traditional engines are due to the physics of fuel combustion. Electric vehicles benefit from simpler design and high efficiency, although infrastructure and range issues remain relevant for now.
In the coming years, manufacturers will continue to improve both types of engines, but it is already clear: visualizing energy losses helps explain why electric vehicles are becoming increasingly appealing to buyers.