An electric vehicle uses one or more electric traction motors for propulsion. A conventional internal combustion engine vehicle makes use an IC engine to propel the vehicle. You could have read the basics of electric vehicle, how electric vehicles work, and what is a hybrid car. In this article, we discuss the power trains – Electric power train and hybrid power train.
What is the power train?
A power train is a group of components in a vehicle, that generate power and deliver to the surface where the vehicle travels.
For example, an aircraft power train converts the chemical energy in fuel and transfers the energy to the air to move the vehicle. In a car, it transfers energy to the road.
The power train of an internal combustion engine car includes
- engine
- transmission
- driveshafts
- differentials
- final drive
Electric power train and hybrid power train
Did you guess that an electric power train includes an electric motor? Both hybrid and electric power train include electric machine.
Let’s see what is electric and hybrid power train
Electric power train
An electric power train is the group of components in an electric vehicle that transfers power from the battery to the surface where the vehicle runs. The components in an electric power train are
- Inverter to convert battery DC power to AC to drive induction motor in the vehicle
- Motor to drive the vehicle
- Gears to change the speed
- Differential gears to change the direction of motion
- Wheels and shaft
If the vehicle has hub motor connected, the gears and differential can be avoided. Electric car power train components are highly critical in an electric vehicle since the efficiency of components affects the energy consumption and the distance covered by a single charge.
The reduced range is a major drawback of an electric vehicle. Fewer components in electric drive train reduce the need for frequent charging of electric cars.
Overnight charging of vehicle from home charging stations helps to meet the requirement of the vehicle the next day.
A hub motor which integrated to the wheel avoids the gear and other mechanical couplings. Mechanical parts are less efficient than electrical components in a vehicle. So the removal of a single component would increase the efficiency of the vehicle by reducing the losses.
The power train of hub motor electric vehicle are given below
- Inverter
- Motor
- Wheel
Hybrid power train
A hybrid electric vehicle uses one or more sources of energy along with electricity to run the vehicle. And the mechanism to transfer energy from the energy storage (both fuel and battery) to the surface where the vehicle runs is the hybrid power train.
They comprise of
- Electric Motor
- Inverter
- Gears
- Differentials
- IC engine
- Clutch
- Power splitting mechanisms
- Wheel and shaft
Based on the power train configuration hybrid electric vehicles are classified into micro hybrids, mild hybrids, and strong hybrids. You can read more about them in these posts here and here.
How does power train differ from drive train?
A drive train is a group of components that deliver power to the driving wheel. A drive train comprises all the power train components except the engine or motor that generates power.
A power train is a combination of motor/engine and drive train. An electric vehicle will have an electric machine and conventional cars will have an internal combustion engine in their power train.
The complexity of a drive train drastically reduces the efficiency of the vehicle. The efficiency of a vehicle is critical in the case of the electric drive where a high voltage battery stores energy to drive the vehicle.
Conclusion
A power train is a group of components in a motor vehicle that transfers energy from the energy storage system to the surface where the vehicle runs.
The electric power train consists of Electric motor, inverter, axle, differential, and wheels. Hybrid electric power train contains IC engine and power split mechanisms along with the components of an electric power train.
Key points
- Electric power train
- Hybrid power train
- Difference between power train and drive train
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