hybrid electric vehicles(parallel mode)

Seminar on modern electric vehicles

Hybrid modern electric

vehicles(parallel mode)

•Niladri sekhar mondal(me-123713)•Monica dixit(me-123709)

Under the guidance of Prof. g.a.p.r. sir

contents

•Basic definitions•necessariness

Parallel hybrid drive train

electric vehicles

•Difference with the series mode electric vehicles•Advantages and disadvantages


electric vehicles

•parallel hybrid drive train with torque coupling devices•Parallel hybrid drive train with speed coupling devices


electric vehicles

Hybrid electric vehicles(parallel mode)

An overview of hybrid electric vehicles

HFHFHHDHD

Nissan car

Parallel hybrid drive train(mechanical coupling)

What is parallel hybrid drive train?

A parallel hybrid drive train is drive train in which the engine supplies its mechanical power directly to the driven wheels,ina manner similar to a ic engine vehicles.

The engine is assisted by an electric motor,that is mechanically coupled to the driveline.

The powers of the engine and electric motor are coupled together by mechanical coupling.

In the next figure,it has been shown clearly manner.


The distinguished feature of this architecture is that two mechanical powers from the engine and electric motor are added together by a mechanical coupler.


In this figure, weCan see the Configuration of The parallel hybridElectric drive train


All the features available in the series hybrid trains are also available, in the parallel hybrid trains

There are some advantages of the parallel hybrids over the series.

These are mentioned on the next


Both the engine and the electric motor directly supply torques to the driven wheels and no energy form conversion occurs,thus the enrgy loss may be less

ADVANTAGES OF PARALLEL OVER SERIES

Parallel hybrid drive trains(mechanical coupling)

it is compact because there is no need for an additional generator and the traction motor is smaller than in series.

but also there are some disadvantages along with the advantages are that,


1) The coupling (mechanical)between the engine and the drive wheels ,since the the engine operating points cannot be fixed in a narrow speed and torque region.

2) The other major disadvantage is the complex structure and control.

Parallel hybrid drive train(mechanical coupling) Generally mechanical coupling consists of

torque coupling and speed coupling. What is torque coupling? In torque coupling,the mechanical

coupler adds the torques of the engine and motor torque can be independently controlled .

But the speeds of the engine ,motor,and vehicle are linked

together with a fixed relationships and cannot be independently

controlled because of the power conservation constraint .

Parallel hybrid drive train[speed coupling]

What is speed coupling? In the speed coupling ,the speeds of

the engine and motor can be added together and all the torques are linked together and cannot be independently controlled.

Parallel hybrid drive train with torque coupling

This figure shows some common mechanical Torque-coupling devices AND THEIR UTILISATION

this figure have been used for various concept making purpose,so, in this regard it is important to see this

Torque coupling

The previous fig shows a mechanical torque coupling,which is a three port,two degree of freedom mechanical device.

Port 1 is a unidirectional input ans ports 2 and 3 are bidirectional input or output,but both are not input at the same time.

Here input means the energy flow into the device and output means energy flow out of the device.

Torque coupling

The port 1 is connected to an ic engine directly or through a mechanical transmission.

Port 2 is connected to the shaft of an electric motor directly or through a mechanical transmission.

Port 3 is connected to the driven wheels through a mechanical linkages.

In the cases of steady state ,the power input to the torque coupler is equals to the power output from it.

Now in one cases lets taking that,port 2(electric motor) is propelling.that means,it is input.

Torque coupling calculations

the power output to the vehicle wheels isT3w3=T1w1+T2w2………………..(1) The torque coupler can be expressed as- T3=k1T1+k2T2…………………(2) Where k1 and k2 are the structural parameters

of the torque coupler,which are described by the gear ratios and usually are constant when the device design is fixed.

T3 is the load torque,and T1 and T2 are propeling torques that are independent of each other,and can be independently controlled.

Inthese cases w1,w2,w3 are linked together and cannot be independently controlled,can be expressed by----w3=(w1/k1)=(w2/k2)

Commonly used mechanical torque-coupling devices

Commonly used mechanical torque coupling devices:

Commonly used mechanical torque-coupling devices

Commonly used mechanical torque coupling devices

speed coupling

PARALLEL HYBRID DRIVE TRAIN WITH SPEED COUPLINGThe powers produced by the two power

plants may be coupled together by adding their speeds.

Similar to the mechanical torque coupler,the speed coupler is also a three port,two degree of freedom mechanical devices.

Port 1 may be connected to an IC engine with unidirectional flow.Ports 2 and 3 may be connected to an electric motor and to the load(final drive).

Both of these two have to be bidirectional energy flow.

Mechanical speed coupler

The mechanical speed coupler has the property- w3=k1w1+k2w2 Where k1 and k2 are constants associated with

the structural and geometric design. Among the three speeds,w1,w2,w3,two of them

are independent to each other These can be controlled independently. The torques are linked together by T3=(T1/K1)=(T2/K2*) IN WHICH THE MINIMUM TORQUE DETERMINES

THE OTHER TWO

Planetary gear used as a speed coupling device

Speed and torque relationships while one element is fixed

Transmotor used as a speed coupler

Speed couplingHybrid electric drive train with speed coupling of a planetary gear unit

Speed coupling devices

Similar to the torque-coupling device,the speed coupling units can be used to constitute various hybrid drive trains.

In the prev. fig the engine supplies its power to the sun gear through a clutch and transmission.

The transmission is used to modify the speed-torque profile of the engine,so as to match the traction requirements.

The transmission may be multigeared or single geared .

The data, which are directly have been prepared from the book of:

“Modern Electric ,Hybrid Electrics and Fuel Cell Vehicles “,

By------ Mehraad EhsaaniYimin GaoAli Emadi

Thankyou

hybrid electric vehicles(parallel mode)

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