Caricarz Guide to Hybrids: What Are HEVs, PHEVs and MHEVs?

The impending electromobility age has prompted many automakers to electrify their offerings in varying degrees. However, the path towards total electrification proved too ‘great’ to be done immediately as EVs require a whole new ecosystem to sustain them, not forgetting their astronomical prices being the biggest hurdles for man to adopt them.

Fortunately, hybrids are here to bridge the gap between ICE-cars and EVs, providing a ‘second-life’ for many ICE-powered vehicles out there while also being deemed ‘clean’ enough to pass the ever-stricter emission regulations. Beyond the ‘standard’ hybrid vehicles, there are several other types of hybrids available out there, which can be confusing for those who are unfamiliar with them.

Fret not, as we here at Caricarz.com have come up with this comprehensive guide to hybrid vehicles, including the types, similarities and differences, as well as each of their pros and cons. Hopefully, this guide should help you pick the right choice for your first step towards electromobility.

What are Hybrid Electric Vehicles (HEVs)?

As its name suggests, a hybrid is defined by a vehicle which uses a powertrain that harnesses both traditional internal combustion and an electric motor power generation methods. Both the engine and motor can either work in-tandem or individually, depending on the drive mode.

With the ICE not working alone to provide drive to the car, hybrid vehicles are noticeably more fuel efficient compared to non-hybrid combustion vehicles. More importantly, hybrids output dramatically lower emissions over said combustion opposites too.

Aside from being efficient and clean, several automakers even took advantage of the sheer torque output and immediate power delivery of electric motors to bolster performance of their sportscars.

In short, what you must remember here is that hybrid vehicles are noticeably cleaner, more efficient, and sometimes even boast better performance over traditional ICE cars. As hybrid technology advances year-on-year, several variations have spawned, and we’ve detailed each of them in the following sections.

Series-Parallel Hybrid (HEV)

Also known as full-hybrid or self-charging hybrid, Series-Parallel Hybrid has stood as the ‘default’ form of hybrid cars for aeons. Its powertrain setup consists of a traditional ICE, which is paired with an electric motor setup juiced by a small battery pack.

Honda HR-V e:HEV RS uses a 1.5-litre Atkinson-Cycle hybrid powertrain

Having both the ICE and electric elements working independently or in-tandem, HEVs offer EV-like features such as regenerative braking, single-pedal driving mode, as well as all-electric driving mode, the latter albeit limited in both range and speed. At higher speeds, some hybrids see both the ICE and electric motor working together to deliver as much power as they are capable of.

Unlike EVs, the small batteries in HEVs do not require external charging, which explains why it is called a self-charging hybrid. Instead, said batteries can charge itself via the aforementioned regenerative braking, as well as drawing power from the engine. In the latter case, the ICE serves as a generator to both the motor and battery pack, providing enough power for them to run at certain speeds and conditions.

Honda Civic e:HEV RS (left) & Toyota Innova Zenix HEV (right)

Notable examples of HEVs on sale in our market now include e:HEV RS variants of the Honda City, City Hatchback, Civic, and HR-V. Meanwhile, Toyota also has several HEV models on sale such as the recently launched Innova Zenix MPV, and the Corolla Cross Hybrid.

To sum things up, HEVs as such sit in between full ICE cars and EVs, providing a cleaner, more efficient alternative without the EV-related hassles like locating charging stations, range anxieties and more.

Mild Hybrid Vehicle (MHEV)

While HEVs sit right in the middle between ICEs and EVs, mild hybrid vehicles (MHEV) lean towards the former side more. Similar to HEVs, MHEV setup consists of a traditional ICE primed with a 48-volt generator-motor – the latter is in place of the starter-motor in conventional ICE setups.

There are two common types of generator-motor used on MHEVs – belt starter-generator (BSG) or integrated starter-generator (ISG). The former is a lot more common in older, cheaper MHEVs due to its low-cost integration. ISGs are the more efficient and pricier option, providing better energy recovery and torque.

MHEV uses a traditional ICE that is mated to a genetor-motor, juiced by a small 48-volt battery

Said generator-motor provides brief boosts to the ICE, especially when accelerating from standstill. These also  assist the engine and help smoothen both acceleration and the idling stop start-stop module. Unlike HEVs, MHEVs do not offer all-electric driving mode, with the only EV-like function available being the regenerative braking, which helps to recharge the small 48-volt battery it harnesses.

Mercedes-Benz C200 Avantgarde (left) & Proton X90 SUV (right)

Most of the time, MHEVs exist as a stop-gap measure for automakers towards reducing exhaust emission in their ICE models, while providing mild improvements in fuel efficiency. Notable examples of MHEVs include the bulk of current-gen Mercedes-Benz models like the W206-gen C-Class, as well as the newly-launched Proton X90 SUV – which also stands as the nation’s first-ever locally-built hybrid vehicle.

What you need to remember about MHEVs is that they are the ideal choice for those who still yearn for a traditional ICE-powered vehicle in this age of stricter emission regulations.

Plug-in Hybrid (PHEV)

Plug-in hybrids (PHEV) serve as a perfect stepping stone between ‘conventional’ hybrids and EVs. Just like other hybrids, a standard PHEV powertrain comprises of an ICE that is paired to an electric motor setup juiced by a battery pack. 

What really set PHEVs apart from other hybrids is its adoption of bigger battery packs and a peppier electric motor to match. Crucially, the electric motor setup can consist of more than one motor, while the battery pack is rechargeable via a plug-in port, as its name suggests.

Just like an EV, PHEV batteries are rechargeable via plug-in EV chargers

Depending on the model, PHEV batteries can range from 120-volt to 240-volt, and they can be recharged from a commercial power grid, just like an EV. Most PHEVs only support slow AC charging input, but some newer models can support DC fast charging inputs at a rate as high as 50 kW. Aside from plugging-in, PHEV batteries can be recharged by the car via regenerative braking, or having the ICE double up as a generator.

The addition of electric motor(s) grants several PHEVs with sheer performance!

The larger battery pack and stronger electric motor(s) grant PHEVs more EV-like features like regenerative braking, all-electric driving mode, and more. Crucially, PHEVs offer longer all-electric range over HEVs, with several models able to cover over 100 KM on a single charge too. The presence of beefier electric motor(s) also mean automakers can fit PHEVs with smaller ICEs, but their performance is on-par or even marginally better compared to traditional options with bigger-capacity powerplants.

Mercedes-Benz GLC300e Coupe (top-left), Ferrari 296 GTB (top-right), Mercedes-AMG GT63S E-Performance (bottom-left), & BMW XM (bottom-right)

The addition of electric motor(s) dramatically increases PHEV’s performance so much so that even several sportscar makers have adopted this setup in their quest for speed. Notable examples of PHEV on sale today include the Mercedes-Benz GLC300e Coupe, any Recharge T8-badged Volvo S60, V60, XC60, S90, V90 and XC90, as well as performance models like the Ferrari 296 GTB, Mercedes-AMG GT63S E-Performance, and the BMW XM.

To conclude, you could say that PHEVs are the perfect ‘trial package’ or ‘preview’ of a full-blown EV as its EV-like functions and perks can help mentally prepare you for future EV adoption, minus the range and charge-point anxiety.

So, which hybrid is for you?

Regardless of type, hybrids stand to offer a host of advantages over traditional ICE cars, aside from providing the perfect bridge between the former and full-blown EVs. With EV adoption in Malaysia still in its growth phase, perhaps certain hybrids can be the perfect litmus test for those who are still sceptical about the performance and efficiency of electrified vehicles, while bridging them closer to EVs from time to time.

Check out the Lexus ES300h HEV (left) & Mercedes-Benz C350e PHEV (right) on sale on Caricarz!

So, have you decided which type of hybrid is suited for you? Keen to own one now? Aside from the examples we mentioned earlier and new models, check out the various used and recon hybrid vehicles listed for sale by our dealer-partners by clicking these blue words…