Renault Group

What's the principle behind the hybrid car?

20 November 2019
5 min
At a time when drivers are really taking global warming and air pollution seriously, vehicle manufacturers are competing with innovations to bring their customers the most environmentally beneficial cars. Hybrid vehicles meet users’ needs immediately by significantly reducing emissions.
by Renault Group

Hybrid vehicles are a first step towards going electric when it comes to transportation. To bring down the level of polluting emissions produced by combustion engines, they have an electric motor that takes over from or backs up the gas or diesel engine depending on how it is being used. There are several different types of hybrid car, with their own advantages and ways of working.

The different types of hybrid car

Mild hybrid cars

Mild hybrid cars are only partially hybridized and can take some of the strain from the combustion engine to reduce its fuel consumption. These cars have a small battery that can back up the combustion engine, but this technology doesn’t enable electric driving.

Since getting the vehicle moving uses the most energy, this low-level hybridization can reduce fuel consumption in city driving (by 5 to 10%). It is charged by kinetic energy produced from braking and deceleration, which makes it a self-contained system that doesn’t need to be charged via a power outlet.

However, it has so far shown limited performance and the savings in terms of CO2 emissions are low.

Hybrid cars

A hybrid car (or HEV, short for Hybrid Electric Vehicle), has a battery with enough capacity to drive a few kilometers in all-electric mode. Like that of the mild hybrid, this vehicle’s battery gets charged thanks to the conversion of kinetic energy released during braking and deceleration. When city driving, it allows the electric motor to regularly take over from the combustion engine. This way, the driver saves on fuel while enjoying a drive without engine noise or vibrations – qualities unique to the electric vehicle.

The latest-generation models offer more dynamic and flexible performance, like the new range of Renault E-TECH hybrid cars with a smart multi-mode gearbox to switch easily between modes.

For example, the new Renault E-TECH hybrids can be driven in all-electric mode for up to 80% of their city driving mileage. And their fuel consumption for city driving is some 40% lower than that of the equivalent gas engine car.

Rechargeable hybrid cars

A rechargeable hybrid car (or PHEV, short for Plug-in Hybrid Electric Vehicle), is a little closer to an all-electric vehicle, with a higher-capacity rechargeable battery (9.8 kWh for the Renault PHEV range). The rechargeable hybrid vehicle hooks up to a suitable domestic power outlet or a public charging point to “fill up” with electricity. This ability to be charged on the grid gives it an all-electric driving range of several dozen kilometers.

Rechargeable hybrid cars are perfect, for example, for all of the week’s urban journeys in the all-electric mode, without using fossil fuels and thus without creating emissions*. The benefits are clear for both the environment and your wallet! On long trips, the rechargeable hybrid engine behaves like a regular hybrid engine, in that the vehicle starts up electrically and runs partly in electric mode.

Thanks to PHEV models and their ability to be charged on the grid, drivers are taking a big step towards going all-electric.

So how does it work in basic terms? Unlike that of a mild hybrid, the electric motor of a hybrid car or rechargeable hybrid car is actually used to turn the wheels to enable all-electric driving, even . HEV and PHEV vehicles have a traction battery (in addition to the regular battery of a combustion engine car), which is only used to power the electric motor.
During start-up and acceleration, the electric motor of the hybrid and rechargeable hybrid, with its instant torque, takes the place of the combustion engine and makes the vehicle more responsive.

Whatever the degree of hybridization, the electric motor acts as a generator that charges the battery while the car slows down during deceleration and braking. Fuel consumption is reduced thanks to this free energy, which cuts down the running costs accordingly.
Rechargeable hybrid models also have a higher-capacity traction battery. The car can be hooked up to the electrical grid to charge the battery, and thus lengthen the range in all-electric mode.

The advantages of the hybrid vehicle

By combining an electric motor with a combustion engine, hybrid cars can reduce emissions in use* and fossil fuel consumption by 5 to 40% depending on the level of hybridization. Hybrid and rechargeable hybrid cars also have the advantage of being free of engine noise, along with the dynamic yet relaxed driving experience of the electric mode.
On top of these main qualities, we can add smart energy management thanks to various calculators that optimize the vehicle’s yield in real time and offer the best performance whatever the conditions.
In addition, Renault’s hybrid vehicles come packed with all the expertise and know-how of Europe’s number 1 in the electric vehicle market.

Hybrid vs. electric cars

As well as being less dependent on charging facilities to handle long distances, hybrids also have a high-performance gas engine that meets the latest environmental standards.
As for the all-electric car, whatever the journey, it can be relied on for full power upon start-up, powerful steady acceleration and dynamic slick handling, all free of engine noise.


*Neither atmospheric emissions of CO2 nor pollutants while driving (excluding wear parts)

Copyrights : He&Me, Jean-Brice LEMAL, Olivier MARTIN-GAMBIER.

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