NEWS

12May
2020

Hybrid guide playbook

Hybrid guide playbook

Over the past years, the dynamic increase in the number of vehicles has led to increased fuel consumption and air pollution. One solution for overcoming this problem is the use of hybrid technology, as it is environmentally friendly and efficient in terms of fuel consumption.

There are four main types of hybrid drive technologies.

“serial” hybrid: the vehicle is driven by an electric motor. The internal combustion engine (petrol/diesel) is not connected to the wheels; therefore, it does not provide drive, acting only as a generator.

“parallel” hybrid: the internal combustion engine and the electric motor connected to it drive the vehicle simultaneously. The output of the two power sources is added, actually allowing the electric motor to give a significant boost to the internal combustion engine.

“soft 4x4” hybrid: they operate similarly to parallel hybrids, but instead of the electric motor and the internal combustion engine being connected they act on different axles. If the internal combustion engine is driving the front wheels, the electric motor the rear ones, and vice versa. This enables part-time four-wheel drive, although that is a far more complex system within hybrid drives.

“series-parallel” hybrid: combines the series and parallel drive technologies, with a power distributor that enables the internal combustion engine to drive the wheels or the electric motor to function as a “generator”. The electric motor can even boost the power of the internal combustion engine or drive the car on its own. A control unit determines which power source is more appropriate for the given driving- and traffic conditions. To help you recognise this technology: this system operates in all Toyota hybrids.

What is the difference between “self-charging”, “plug-in” and soft hybrids?

“Self-charging” hybrid

Also known as traditional hybrid, as it was the first available hybrid type. It consists of an internal combustion engine connected to a medium-sized electric motor which can drive the car on its own, or when not, significantly boost the power of the internal combustion engine.

These hybrids do not need to be connected to an electric power source – the battery is charged during braking and in engine brake mode.

Although it is true that the batteries of these cars are charged without an external power source, their battery is rather small, so they can only travel a few kilometres using electrical energy.

This hybrid type is in fact most efficient in urban traffic. In a city, constant acceleration and deceleration produces frequent regenerative braking, which charges the battery, leaving more electrical energy available for switching off the internal combustion engine and travelling in electric mode for short distances.

Plug-in hybrids

As their name suggests, they also possess a system for charging their battery that can be connected to an external power source.

These vehicles are equipped with a larger battery and electric motor than “self-charging” hybrids. They can, therefore, travel larger distances using purely electric drive.

The use of plug-in hybrids, however, requires awareness. It is not enough having selective collection at home: if we throw waste in containers at random, that is not selective waste collection. The same way, it is important that the owner of the plug-in hybrid car regularly charge the battery of their vehicle from a connected external power source. Without this the system represents only extra weight, due to which the CO2 emission of a badly used plug-in hybrid may exceed that of a diesel engine vehicle of the same category. In addition, there is no return on the higher price with respect to “self-charging” hybrids.

“Soft” hybrids

Due to the increasingly stricter regulation on harmful emissions manufacturers entering the hybrid market created the next step of the technology. A “soft” hybrid operates the same way as a parallel hybrid, but its battery, internal combustion engine and electric motor are far smaller.

“Soft” hybrids cannot travel solely on electric drive. They behave the same way as a traditional petrol- or diesel vehicle, enabling the use of smaller internal combustion engines, which, with the assistance of the electric motor, reach the same power as large motors, with more moderate fuel consumption. 

The advantages of the efficiency of the ”soft” hybrid system, however, are limited with respect to “self-charging” hybrids or correctly used plug-in hybrids, as the size of the battery, and, therefore, electric assistance is limited.

Author: Endre Deáki - ALD Head of Technical, Body Repair and Invoicing