Hybrid sales have taken off in South Africa over the last few years as motorists are keen to save as much as they can on petrol, but not every model is capable of returning a frugal consumption figure.
More and more carmakers are starting to introduce “mild hybrids” (MHEVs) to capitalize on the demand for new-energy vehicles (NEVs) nowadays, but the technology is more limited than people may realize.
Different types of hybrids
There are several different types of hybrids on the market, which can complicate the browsing process when looking for your next car.
The electrical systems on an MHEV consist of an integrated starter generator and a small battery with a voltage of 12V, 24V, or 48V, which replace the standard starter motor and alternator used in traditional cars.
The generator assists the combustion engine with a small amount of extra torque at low speeds, which in turn fractionally improves throttle response and fuel efficiency.
Examples like the Toyota Fortuner and Hilux MHEVs also have a reduced engine idle speed of 600rpm instead of 720rpm, as well as a Stop/Start function to reduce fuel waste when stopped.
The important thing to bear in mind with these systems is that the fuel-savings offered tend to be very minor, as the Toyota claims its MHEVs simply provide 5% more efficiency.
Another brand, Suzuki, has a single MHEV in South Africa in the form of the flagship Grand Vitara, which has an official consumption of 5.6l/100km compared to 6.0l/100km for its non-electrified counterpart.
MHEV Suzuki Grand Vitara
In contrast, traditional hybrids (HEVs) like the Toyota Corolla Cross and Haval Jolion have a much more powerful e-motor connected to the drivetrain.
The e-motor is capable of driving the wheels at low speeds (usually under 30km/h) and vastly improves efficiency in traffic on shorter trips, which constitute the majority of a person’s daily excursions.
There are also plug-in hybrids (PHEVs) like the BMW X1 with much larger batteries and e-motors allowing for all-electric driving for limited distances, often in the ballpark of 50km to 100km.
The trade-off is these batteries need to be plugged into an external power source to fully replenish, but the idea is that you can treat a PHEV as a fully-electric vehicle for most trips and only dip into the fuel tank when you need to go further afield.
PHEV BMW X1 xDrive30e
Mild hybrids are not “true” hybrids
The fundamental difference between MHEVs, HEVs, and PHEVs is that the latter two are capable of electric driving to varying degrees, while the former is not.
The petrol or diesel engine is always doing the work on an MHEV, which is why the fuel savings are so small.
This has led to criticism from industry regulators and media outlets claiming that the term “mild hybrid” is deceptive marketing due to the strong association that hybrids have with new-energy powertrains.
Australian publication CarsGuide’s editorial head Justin Hilliard argues that the industry needs to adopt a new term for MHEVs, as many automakers have tried to downplay the “mild” aspect of the technology.
For example, Mazda’s MHEVs are labelled as “M Hybrids” which customers could assume to mean “Mazda” rather than “Mild” hybrids.
Toyota simply advertises its MHEVs as “48V” units to not conflate units like the Fortuner and Hilux with its “true” hybrids like the Corolla Cross and Rav4.
Another manufacturer, Mercedes-Benz, has started to include 48V tech on most of its new models as standard, but does not advertise any of these as hybrids.
Mercedes-Benz A-Class with MHEV tech
In contrast, Suzuki describes its Grand Vitara as a “Smart Hybrid Vehicle” or just purely as a hybrid, but the term “mild” is not included in the main model name.
Instead, a customer must navigate to the Grand Vitara’s specification breakdown or the brochure on the Suzuki website and click on the “Hybrid AllGrip” model before seeing the engine being expressed as a “1.5l mild hybrid.”
Industry regulators tend to agree that mild hybrids are not considered NEVs as they are not as fuel efficient or environmentally friendly, which is why organizations like Naamsa do not include MHEVs when tallying the sales for hybrid and electric cars every month.
Similarly, many countries that offer purchasing incentives for NEVs do not extend their policies to mild hybrids.
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