Hybrid 101: Demystifying MHEV, HEV, PHEV, and understanding whether Toyota, Honda, or Perodua hybrids are best for you
Eric · Sep 30, 2022 12:55 PM
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Hybrid cars are not new to Malaysians, seeing that they have been available in Malaysia for roughly 15 years with the introduction of the FD-generation Honda Civic Hybrid.
And today, hybrids are even more popular, as manufacturers like Honda, Toyota, and Nissan all offer at least one hybrid model in their line-up here in Malaysia. More recently, Perodua has thrown their hat in the ring with the 2022 Perodua Ativa Hybrid.
On one of the presentation slides that Perodua showed, the second national carmaker stated that the Ativa Hybrid is a series hybrid model, different from parallel and series-parallel hybrids.
But what separates a series hybrid from a parallel hybrid and a series-parallel hybrid? Let’s dive deeper by taking a look at popular hybrid technologies.
Mild-hybrid (MHEV)
First and foremost is mild-hybrid (MHEV). Although mild-hybrids feature an electric motor, its electric motor only functions to assist the engine and cannot accelerate from standstill on electric power alone.
Compared to other hybrid solutions, mild-hybrids are the cheapest to manufacture due to their simplicity and smaller battery capacity, but the trade-off is lower performance and improvements in fuel efficiency isn't that great.
Notable cars with a mild-hybrid system include Honda's range of older hybrid models with the Integrated Motor Assist (IMA) system (CRZ, Insight, and Civic). Newer examples with a mild-hybrid system include the Mercedes-Benz C200 and C300 with EQ Boost.
What about the Nissan Serena S-Hybrid then? That's not a real hybrid, not even a mild-hybrid, as there is no motor to assist / drive the wheels, only an upgraded engine starter motor and a secondary 12V battery for better engine start-stop performance.
Full-hybrid vehicles are more advanced than mild-hybrid vehicles. Full-hybrids can accelerate from standstill in electric power alone and offer higher performance than mild-hybrids. However, due to their complex hybrid system and larger battery capacity (typically around the 1 kWh mark, larger than MHEV), it’s more expensive to manufacture a full-hybrid vehicle.
But that’s not all – full-hybrid vehicles are split into three distinctive types: Series hybrid, parallel hybrid, and series-parallel hybrid.
Series hybrid
Think of series hybrids as EVs with their own power generator under the hood. Series hybrids typically feature a petrol engine, but unlike other hybrid systems out there, the petrol engine’s sole duty is to charge the battery.
In a parallel hybrid system, there are two paths of power turning the wheels, hence the term parallel. Both the engine and electric motor can drive the car individually, or simultaneously.
The Jazz Hybrid featured an i-DCD hybrid powertrain
Examples of cars with a parallel hybrid system include Honda’s previous generation i-DCD range (City, Jazz, HR-V), as well as all German marques like BMW.
A series-parallel hybrid is the most advanced (and also most expensive) of non-plugged-in electrified vehicles. It combines the benefits of a series and parallel hybrid system into one.
In a series-parallel hybrid, there are 2 electric motors. Cheaper series / parallel hybrids have only 1 motor. With only one motor, the system can either drive the car, or recharge the battery, but not at the same time. With two motors, it can, thus allowing it to operate either as a series hybrid or a parallel hybrid.
Honda Insight shown, different model but uses a similar i-MMD setup
Examples of series-parallel hybrids include Honda’s e:HEV (or i-MMD) and Toyota Hybrid System. Honda's e:HEV will run in series mode (electric motor or engine driving the wheels) longer than Toyota.
Mercedes-Benz's illustration of a plug-in hybrid A-Class
A plug-in hybrid (PHEV) is a hybrid vehicle that features a charging socket that can be used to charge the battery pack. Seeing that plug-in hybrids’ battery capacity (typically around or more than the 20 kWh mark) is second only to a full battery electric vehicle (BEV), PHEVs can travel purely on electric power alone, with a range of up to 100 km (model dependent).
Almost all PHEVs are parallel hybrids, with a motor nestled inside a modified automatic transmission.
The not-sold-in-Malaysia, 4th gen Toyota Prius is available as a regular HEV or PHEV
That said, when it comes to vehicle weight, PHEVs are generally heavier than their HEV counterparts, owing to their larger battery capacity. For example, the Toyota Prius PHV is roughly 200 kg heavier than the regular Toyota Prius.
With the exception of a series hybrid (ETCM does not sell any e-Power cars here and the Ativa Hybrid is only for leasing), practically every other hybrid system can be found in cars sold here in Malaysia.
Question is, seeing that fuel subsidies will be removed next year, will your next car purchase be a hybrid?
Started from the IT industry but somehow managed to find his way into the automotive industry. If he’s not gaming, he’s constantly tinkering with his daily/weekend car.
