What is Parallel HEVs how it works

 Parallel HEVs

Above Figure aa shows the configuration of a parallel hybrid. Into this configuration,both the ICE

and the electric motor can provide the power in parallel to the wheels of the vehicle. 

The ICE and the

electric motor are attached with the final drive through a mechanism known as a clutch mechanism, belts mechanism,

pulleys, and gears mechanism.

 Both the ICE and the motor can deliver power to the final drive, either seperately.

in combined mode, or in separate mode. The electric motor can be used as a power generator means to recover or to converts energy means the kinetic energy during braking or absorbing a portion of power from the ICE.

The parallel hybrid needs only two propulsion devices, the ICE and the electric motor,

which can be used in the following mode:

• Motor-alone mode:  

When the battery has sufficient energy, and the vehicle needed low power


then the engine ICE is turned off, and the vehicle is powered by only motor and battery only.


• Combined power mode: 

when high power merge or high power demands, then the engine is turned on and the

motor also supplies power to the wheels.

• Engine-alone mode:

 During highway when vehicle is cruising at medium speed and at moderately high power demands,

then the engine provides all the power needed to drive the wheels of vehicle. 

During this time the motor remains in idle/off condition.

This is mostly due to the fact that the battery SOC is already at a high level but the

power demand of the vehicle prevents the engine from turning off, or it may not be

efficient to turn the engine off.

• Power split mode: 

When the engine is on, but the vehicle power demand is low

and the battery SOC is also low, then this time of period a part of the engine power is converted to

electricity by the motor to charging the battery.

• Stationary charging mode: The battery is charged by running the electric motor as a generator

and this motor is driven by the engine, without the vehicle being driven.

• Regenerative braking mode: 

The electric motor is operated as a generator to convert the vehicle’s kinetic energy into electric energy and store this energy into the battery. Note

that, in regenerative braking mode, it is in principle possible to run the engine as well, and

provide additional current to charge the battery more quickly (while the propulsion

motor is in generator mode) and command its torque accordingly, that is, to match

the total battery power input. In this case, the engine and motor controllers have to be

properly coordinated.



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