hybrid electric vehicles(parallel mode)
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Seminar on modern electric vehiclesUnder the guidance of Prof. g.a.p.r. sir
Hybrid modern electric vehicles(parallel mode)
Niladri sekhar mondal(me123713) Monica dixit(me123709)
contentsParallel hybrid Basic definitions necessariness drive train electric vehicles Parallel hybrid Difference with the series mode electric vehicles drive train electric vehicles Advantages and disadvantages Parallel hybrid parallel hybrid drive train with torque coupling devices drive train Parallel hybrid drive train with speed coupling electric vehicles devices
Hybrid electric vehicles(parallel mode)
An overview of hybrid electric vehicles
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.
Parallel hybrid drive train
The distinguished feature of this
architecture is that two mechanical powers from the engine and electric motor are added together by a mechanical coupler.
Parallel hybrid drive train(mechanical coupling)In this figure, we Can see the Configuration of The parallel hybrid Electric drive train
Parallel hybrid drive train(mechanical coupling) 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
Parallel hybrid drive train(mechanical coupling)ADVANTAGES OF PARALLEL OVER SERIES
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
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,
Parallel hybrid drive train(mechanical coupling)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 Torquecoupling 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 is T3w3=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 torquecoupling devices
Commonly used mechanical torque coupling devices
PARALLEL HYBRID DRIVE TRAIN WITH SPEED COUPLING The 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 speedtorque 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 Ehsaani Yimin Gao Ali Emadi