Week-4 Challenge WOT Condition Part-2

1. What is the 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 to measure performance parameters of the vehicle by using standard lookup tables which are prefed to the system. This type of modelling is less accurate. The lookup tables value are based on the values of brake torque, commanded torque and engine speed. If any other parameter like 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.

   Dynamic 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 permanent 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 motor 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. Its 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.

How can you change model type?

open the ev model in simulink.

EvReferenceApplication/Passenger Car/Electric Plant/Motor

inside the motor block right click to find the variant option.

2)How does the model calculate miles per gallon? Which factors are considered to model fuel flow?

Since engines that can use an alternative source of fuel cant be measured by liquid gallons of fuel,the mpge rating is calculated by figuring out the number of milles a vehicle can go using the same energy content as gallon of gas.the epa calculated that 33.7 kilowatt hours of electriccity is equivalent to one gallon of gas.

Here,three different inputs are taken into considerations:

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.

3)Run the HEV ReferenceApplication with WOT drive cycle. Change the grade and wind velocity in the environment block. Comment on the results.

Block diagram of EV

Drive cycle source set to WOT

And also set the grade to 10 and air pressure to 25

Result

plot 1:trace velocity,target,actual:

top velocity achieved =50.1 mph.

time taken to accelerate = 29.034 sec.

time taken to deaccelerate = 2.471 sec.

plot 2: motor&engine rpm:

top motor rpm=5712 rpm.

top engine rpm = 5451 rpm.

plot 3:motor& engine torque:

maximum motor torque = 306.6 N-m.

maximum engine torque = 174.7 N-m.

4)Keeping all other parameters same, compare the simulated results of hybrid and pure electric powertrains.

EVR

HEv

Conclusion:

1.The top speed is achieved by hybrid electric vehicle is more than that of EV.

2.The battery current capacity of pure EV is much higher compared to that of HEV since in EV battery is the only driving unit.

3.Higher fuel economy is achieved in case of pure EV.

it has regenrative powers