A is a variety of hybrid vehicle. It differs from full hybrids () and plug-in hybrids (). This is also known as a light hybrid or micro-hybrid car.
And for good reason, the hybridization system used in MHEVs is much less sophisticated and energy-efficient than in full-hybrid cars or plug-in hybrids.
Lightweight hybrid cars are an interesting first level of hybridization to reduce the carbon emissions of thermal engines (gasoline or diesel) and thus meet increasingly stringent European standards.
In micro-hybrid cars, the vehicle's internal combustion engine (ICE) is slightly assisted by an electric starter-alternator. The combustion engine (gasoline or diesel) and the starter-alternator are connected by a timing belt.
A battery with a voltage limit of 48 volts (V) completes the device which allows:
In traffic, the vehicle's deceleration energy is recovered during braking to recharge the battery. The captured energy is immediately reused to relieve the combustion engine, thus consuming less fuel.
This hybridization system does not require major changes to the vehicle's architecture. Relatively simple to install, it is therefore inexpensive compared to the hybridization systems of full hybrid or plug-in hybrid vehicles.
However, the fuel savings of a mild hybrid car are much more limited. Therefore, light hybrid cars cannot really be considered as clean vehicles. This is why they are not eligible for the eco rebate.
The use of the starter-alternator nevertheless makes it possible to reduce the fuel consumption of vehicles, and consequently to limit their carbon emissions. The fuel savings are greater in urban areas due to the use of the Start & Stop system.
Depending on the vehicle model, the battery voltage on mild hybrid cars is 12, 24 or 48 V. Today, a majority of MHEVs have a 48 V hybrid system.
In February 20211, sales of non-plug-in hybrids accounted for 16.1 percent of vehicles sold compared to 8.4 percent in February 2020.
According to an AAA Data study, 21,162 non-plug-in hybrid cars were put into service in February 2021. This volume represents about 70% of the electrified vehicles sold during this period.
Of all non-plug-in hybrids put on the road in February 2021:
In a study carried out in France, Germany, the Netherlands and Portugal, Inovev estimates that MHEVs (Mild Hybrid Electric Vehicles) will account for nearly 15% of the European car market in 2021, twice as much as in 2020.
Over the ten months of fiscal 2021, Audi, BMW, Ford, Suzuki, Hyundai, Fiat, Mazda, Kia, Volvo and Mercedes-Benz were the brands that sold the most mild hybrid cars in these countries.
At the end of October 2021, the Fiat 500, Ford Puma and BMW 3 Series were the three best-selling mild hybrid vehicles in the four countries that were considered.
At the European level, the reference text for hybrid electric vehicles is Regulation No. 100 of the United Nations Economic Commission for Europe (UNECE). Applied to all vehicles since January 1st, 2013, it establishes uniform requirements for the approval of battery electric vehicles.
The regulations related to hybrid electric cars mainly concern safety issues related to:
It can refer to existing ISO standards2 :
Thanks to the fuel savings achieved on thermal engines, mild-hybrid cars can meet the so-called Euro standards set for carbon emissions. Over the years and with each new version, however, these standards have become more and more restrictive in order to meet the carbon neutrality objectives to be reached by 2050.
Emerging in 2015, mild hybrid technology has therefore really taken off after the tightening of European carbon emission rules. It allows manufacturers to comply with regulatory requirements.