Hybrid Highway: Two into one

The first mass-produced hybrid vehicle, the Toyota Prius, went on sale in 1997, but it was nearly a century earlier that the first hybrid automobile was developed.

In 1897, German carmaker Henri Pieper unveiled his petro-electric automobile, and a year later his countryman Ferdinand Porsche also developed a gasoline-electric hybrid vehicle.

When put up against that first generation Prius, those two early hybrids appear crude comparisons, but in fact they work using the same basic principle as the groundbreaking Prius — two distinct power sources to turn the wheels of a vehicle. Hence the term ‘hybrid.’

And today there are a few kinds of hybrid systems powering passenger vehicles.

The most common is the gasoline-electric hybrid vehicle, which combines a gas-powered internal combustion engine working with an electric motor that captures energy usually lost when a driver brakes. That energy is stored in a lithium-ion battery pack that in turn provides the power for the vehicle to run. The batteries are constantly being charged while the car is in motion.

A 21st Century hybrid engine.

A 21st Century hybrid engine.
Thinkstock.com, Driving

There are two types of hybrids that fit in the gasoline-electric categories.

In a series hybrid, the electric motor handles all the driving and the gasoline engine only recharges the battery pack. When the driver starts the engine, power is received from the battery pack to the electric motor which turns the wheels. On trips longer than 80 kilometres, the gas engine provides power. Series hybrid vehicles are often called extended-range electric vehicles

A parallel hybrid also uses an internal combustion and an electric motor, but the conventional and electric engines are attached to one transmission — meaning they both power the car at the same time. The fuel tank supplies gasoline to the engine while the generator charges the batteries. This type of hybrid is more suitable for traveling long distances and examples of parallel hybrid vehicles include the Chevy Malibu and the Toyota Prius.

A further variation is the mild hybrid, which doesn’t function on just the electric engine and is the least expensive hybrid option available. In this system the electric motor assists the gas engine when more power is needed. When the car stops, say in heavy traffic, the vehicle shuts down. When the accelerator is applied, the battery starts the motor again.

And finally, there are hybrid-electric vehicles, which combine the benefits of gasoline engines and electric motors and can be configured to obtain different objectives, such as improved fuel economy, increased power, or additional auxiliary power for electronic devices and power tools.

An emerging trend in hybrids is plug-in charging systems.

An emerging trend in hybrids is plug-in charging systems.
Thinkstock.com, Driving

Regardless of what kind of hybrid system employed, there are technologies they all share. These include:

Regenerative braking, in which the electric motor applies resistance to the drivetrain causing the wheels to slow down. In return, the energy from the wheels turn the motor, which functions as a generator, converting energy normally wasted during coasting and braking into electricity, which is stored in a battery until needed by the electric motor.

Electric Motor Drive/Assist features the electric motor providing additional power to assist the engine in accelerating, passing, or hill climbing. This allows a smaller, more efficient engine to be used. In some vehicles, the motor alone provides power for low-speed driving conditions where internal combustion engines are least efficient.

Automatic start/stop automatically shuts off the engine when the vehicle comes to a stop and restarts it when the accelerator is pressed. This prevents wasted energy during idling and less pollution from the exhaust system.
The new kids on the hybrid block are plug-in hybrid electric vehicles, or PHEVs, which uses a traditional gasoline-powered engine, but only once all the battery power is depleted. The battery packs can be charged in standard electric outlets, EV charging stations or in some cases an electrical generator on board the vehicles.

About Andrew McCredie