Week-4 Challenge WOT Condition Part-2

1.

A model is a simplified representation of some real world entity such as a car engine,a motor or a generator.Table-VII enclosed shows the difference between a Mapped Model and a Dynamic Model.

The technique of changing the model type is explained taking the example of a motor.After entering Passenger car block>Electric Plant>Motor we get an window where MotGenMapped is by default selected as a model type for motor.To change from MotGenEvMapped to MotGenEvDynamic first we need to open our reference model into MATLAB.Then after clicking on the modeling section and subsequently in the design block we need to select the Variant Manager option.After the Variant Manager window gets opened by clicking on the Passenger car expand option there will be Electric Plant option .If we expand that too we will get Battery and Motor option.After expanding Motor option we will get the followings:

I.MotGenEVdynamic

II.MotGenEVmapped

In this way we can select MotGenEVdynamic and change from MotGenmapped.

2.

MPG stands for Miles Per Gallon.It is the distance that a car can travel per gallon of fuel consumed.It is the primary measurement of a car's fuel efficiency and offers a yardstick for comparison of various model of cars.The agency responsible for a vehicle's MPG figures in USA is known as EPA.Each vehicle is given three different MPG ratings,namely:Highway MPG,City MPG and Combined MPG.Hybrid and Electric vehicles are also included in this rating.

To calculate the fuel flow vehicle speed and battery power are taken into consideration.At first battery power in watts is converted into Kwatts and further converted into KWatthr.This is then converted into US Gallon equivalent energy by dividing it by a standard value of 33.7.Then it is converted into US Gallons per second.It is multiplied by standard value 0.00378541 to get volume in cubic meter per Gallon and then added to the fuel flow for total value because it is a hybrid vehicle or HEV.Further, meter cube is converted into US Gallon.On the other hand, the speed of the vehicle is integrated to get distance and the distance which is in meter is converted into mile by multiplying it with a standard value of 0.000621371.

In the case of a pure electric vehicle(EV) the term Miles Per Gallon is equivalent to MPGe.

Factors considered to model fuel flow are as under:

1.Vehicle Speed

2.Fuel Flow

3.Battery Power

3.

HEV reference application was chosen by clicking the appropriate link.The schematic diagram was obtained by typing autoblkHevStart in the command prompt.Double clicking the Drive Cycle block a pop up window was opened.Wide Open Throttle(WOT) was chosen from that and simulation run was carried out.Altogether ten plots were obtained,These are:

1.Trace Velocity,Target,Actual(mph)

2.Eng Spd,Mot Spd,GenSpd(RPM)

3.Eng Trq,Mot Trq,Gen Trq(Nm)

4.Battery Current(A)

5.Battery SOC(%)

6.US Fuel Economy(MPGe)

7.TP HC Mass(g/mi)

8.TP CO Mass(g/mi)

9.TP NOx Mass(g/mi)

10.TP CO2 Mass(g/mi)

Yellow line indicates the trace velocity and blue line indicates the actual velocity.Velocity takes about 20 secs to reach its maximum value and after that time it drops.

By clicking the 'Environment' block Grade was changed to 5% and Wind Velocity to 4 m/sec.The simulation was repeated and again the above mentioned ten plots were obtained.Some change was noticed,but not very profound in nature.

The simulation report has been enclosed in HevMmReference Application file attached.

4.

EV reference model was obtained by clicking the appropriate link.The schematic diagram was derived by typing autoblEvStart and simulation run was carried out.The result has been enclosed vide EvReferenceApplication(minfo.mat) enclosed.The six plots are as under.

1.Trace Velocity(mph)

2.Mtr Speed(RPM)

3.Mtr Trq(Nm)

4.Battery SOC(%)

5.Battery Current(A)

6.US Fuel Economy(MPGa)

It is being observed that EV achieves less velocity compared with HEV.Velocity is less than 60kmph.Motor speed is also less compared with HEV.However,motor torque is same.As seen from plot of SOC battery current use is half in EV to produce same power as in HEV.Also battery use is less and battery draining is low.However, fuel economy is almost double in case of EV compared with HEV|.