What is a hybrid car and how does it work?

An internal combustion engine (ICE) uses a liquid like petrol or diesel as its fuel. A battery electric vehicle (BEV) is powered by an electric motor running on a solid-state (often lithium-ion) battery.

The spectrum in between is where you will find hybrid cars, vehicles with both an ICE and a battery-powered electric motor (other than the standard 12V battery used to start an ICE vehicle).

Hybrid cars come in several different types, depending primarily on the sizes of the ICE and the electric motor:

• Mild hybrids (MHEV) have a small motor used to boost acceleration
• Full hybrids (FHEV) have a larger motor, but their batteries are charged by the ICE
• Plug-in hybrids (PHEV) charge from the mains supply via a plug-in charger
• Range-extended (REEV) are mostly electric, with a small ‘backup’ ICE to get to a charge point if the battery runs flat

By definition, a hybrid vehicle has both an ICE and an electric motor. Most of the top new hybrid cars on the market have plug-in chargers. They can drive considerable distances in fully electric mode, as battery sizes and efficiencies have improved significantly over the years.

Types Of Hybrid Car Configuration

The types of hybrid cars listed above are defined by the sizes of their engines and motors, and how the two are used together or independently.
Another way to refer to hybrid vehicles is as either ‘parallel hybrids’ or ‘series hybrids’, depending on the configuration of the two power sources.

Series Hybrids

A series hybrid does not run directly from its ICE at any time. Instead, the electric motor powers the car, while the ICE uses a traditional fuel like petrol or diesel to generate power to recharge the battery.
This is similar to how a conventional ICE keeps its 12V battery charged during journeys, but on a larger scale, as the higher-capacity hybrid EV batteries need much more energy to keep them charged.

Parallel Hybrids

In a parallel hybrid, both the ICE and electric motor are connected to the transmission. The vehicle manages the power distribution between the two to automatically maintain the most efficient acceleration.
A parallel hybrid never runs in fully electric mode – the electric motor is only there to function as a generator and provide an extra acceleration boost. This helps to ‘smooth out’ moments of high acceleration for more efficient driving.

Series-Parallel Hybrids

Hybrid vehicles that can operate fully from their ICE or fully from their electric motor are called ‘series-parallel’ hybrid cars. This is because their two systems run parallel, with the option to turn one or the other off completely.

This offers three different driving modes:

• Fully electric
• ICE only
• Both combined

As a result, series-parallel hybrids can be very efficient and eco-friendly, offering fully electric acceleration at low speeds ⁠— perfect for stop-start urban driving and conventional ICE acceleration at motorway speeds.
Like a parallel hybrid, series-parallel hybrid vehicles automatically control the power distribution to use the most efficient engine and motor at any given time.

How Is A Hybrid Car Battery Charged?

Some hybrid cars plug in to recharge the main EV battery, but what about those that don’t have a plug-in option?

ICE Charging

Charging from the internal combustion engine is one way hybrids can charge their batteries without plugging in. This is normal for a REEV (range-extended electric vehicle), which usually powers the electric motor using its ICE rather than running directly in ICE mode.

It Might Sound Strange To Add A Motor But Then Power It Using An Ice, But By Accelerating More Smoothly And Combined With Regenerative Charging, This Type Of Hybrid Can Be More Efficient Overall.

Regenerative Charging

So what is regenerative charging on a hybrid vehicle? You may have heard this called KERS (kinetic energy recovery system) in Formula 1 motor racing. Put simply, it’s a way to take energy from the wheels during braking and put it back into the battery.

Ordinarily, when a vehicle brakes, the kinetic energy (i.e. the speed) removed from the wheels is lost as heat (and sometimes sound, which is why brakes squeal when applied hard).

Regenerative charging flips the electric motor into reverse when the car slows down, effectively turning it into a dynamo that puts charge back into the batteries, instead of taking it out.

It’s a great way to increase the maximum range of an electric or hybrid car, and also why the top hybrid car models on the market can be much more efficient than their pure-ICE counterparts.

Was The Prius The First Hybrid Car?

The Toyota Prius hybrid vehicle was launched in Japan in 1997 and went on sale globally in 2000-01. It was the first modern mass-production hybrid car, so in a sense, the Prius was the ‘first hybrid’ – but that’s not the full story.

A century earlier in 1900, a young car designer called Ferdinand Porsche (yes, THAT Porsche) was hired by Jacob Lohner to create an electric powertrain for Lohner’s coaches.

Lohner’s reason for building electric cars? He said the air was being “mercilessly spoiled” by the fumes emitted by large numbers of gasoline engines.

Despite building a working model in 1900 (named the ‘Semper Vivus’, Latin for ‘Always Alive’), the poor performance and lack of supporting infrastructure meant Lohner-Porsche hybrid cars never took off. It would be a hundred years before hybrids would return.

Will Hybrid Cars Disappear?

As governments encourage more production and use of fully electric cars, we will likely see fewer new hybrid vehicles taking to the roads. However, existing hybrids are unlikely to be banned, so we could see them driving around for quite a few more years still to come.

Hybrid car leasing is one way to benefit from the efficiency of the latest hybrid car models, while ensuring that you can easily transition to a fully electric leased BEV when ready. This gives you the best of both worlds, just like a hybrid car aims to do.