Week-4 Challenge WOT Condition Part-2

Student of EV LIVE BATCH 16:

Solution for Question 1:

Difference between mapped and dynamic model of engine,motor and generator:

Mapped Engine: Mapped engine is the default settings in powertrain blockset.It is used to measure performance parameters of the vehicle by using standard lookup tableswhich are prefed to the system. This type of modelling is less accurate. The looup tables values are based on the values of brake torque,commanded torque and engine speed.If any other parameterlike input engine temperature is selected then lookup table values are also a function of the temperature parameter.The data extracted from lookup tables are: air mass flow,fuel flow,emission data,exhaust temperature and efficiency.This data is used to find out other parameters which are needed by the end user.

Dyanmic Engine: This type of model uses real time data fed by the user at run time for modelling.This model is more accurate than mapped engine model.This type of model is used when the data of subsystems of a vehicle is required.We can calculate : Brake torque ,fuel flow ,port gas mass flow,exhaust temperature,exhaust mass flow rate and exhaust emissions.

Mapped Motor: The mapped motor works in torque control mode.This type of motor is used when the user requires a faster simulation and doesn't have the knowledge of motor parameters.The output torque and reference torque is compared and changes are made.Input torque or speed can be specified , electrical losses and maximum motor power and torque can be defined.

Dynamic motor: In the Dynamic motor a three phase interior permanant magnet synchronous motor(PMSM) is used.The block uses three phase input voltages to regulate the individual phase currents , allowing control of the motor torque or speed.This block is used when the user knows what parameters are to be used in that particular simulation.This is more accurate.

Mapped Generator: The mapped generator block is also similar like other blocks.Most of the data required is taken from the lookup tables corresponding to the given input parameters, it's simulation time is less.

Dynamic Generator: The dynamic generator involves user entering the parameters manually during the run time for their particular applications.The results take time and are more accurate.

To change Model type from MAPPED to DYNAMIC:

Go to Modelling in simulink and the variant Mangaer as shown below

For example if we want to change Generator block from mapped to dynamic , select GenDynamic then right click , then select " Set as Label Model Active Choice". Then double click " GenDynamic".

Solution for Question 2:

Miles per gallon (mpg) and miles per gallon equivallent (mpge):

For a conventional gasoline vehicle the fuel efficiency is calculated via miles per gallon (mpg), however fuel efficiency for hybrid electric vehicles is calculated via miles per gasoline equivalent(mpge). mpg is the number of miles your car can drive per gallon of gas. Determining the mpge rating is alittle more complicated since engines that can use an alternative source pf fuel can not be measured by liquid gallons of fue, the mpge rating is calculated by figuring out the number of miles a vehicle can go using same energy content as gallon of gas . the epa calculated that 33.7 kilowatt hours of electricity is equivalent to one gallon of gas.

We should go inside ev refernce block for the performance calculations

we will get the actual mpg calculations here

Here three different inputs are taken into consideration

1.vehicle speed

2.fuel flow

3.battery power

The vehicle speed inputs is in m/s which is converted into miles by multiplying with 0.000621371.

Similarly the kilogram of fuel is converted into cubic meter by multiplying 1/(1000*0.739)

this cubic meter value is then converted into cubic meter by multiplying it with 264.172. the mile value and gallon value is used to find mpg of the vehicle.

Now the battery value is initially converted from watts to kwh by dividing with 1000 and then to gallon equivalent by again dividing it with 33.7(since 33.7 kwh=1 gallon)

then divide the value by 3600 to get in per seconds and multiply by 0.000378541 to get the value in cubic meter per gallons.