Week-4 Challenge WOT Condition Part-2

Q1. What is the difference between mapped and dynamic model of engine, motor and generator? How can you change model type?

Mapped Engine :

• It represent macro engine behaviour as a set of lookup tables (brake torque, fuel flow, air mass flow, exhaust temperature, efficiency and emission) as function of commond load and measured engine speed.
• For that suitable for analysis and design activities that do not required engine subsystem dynamic characteristics.
• For Example : Engine and Transmission Powertrain matching analysis for fuel economy, emissions and performance trades-offs.

Dynamic Engine :

• This type of engine Model is used for real time data fed by user at run time for modelling.
• This model is more accurate than mapped engine model.
• For this type of model is used when the data of subsystems of a vehicle is required.
• We can calculate : Brake troque, Fuel Flow, Port gas mass flow, Exhaust temperature, Exhaust mass flow rate and Exhaust emission.

Mapped Motor :

• 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 :

• Where a three phase interior permanent magnet synchronous motor (PMSM) is used.
• The block uses three phase input voltage to individual phase currents, allowing control of motor torque and speed.
• This block is used when user known what parameters are to be used in that particular simulation. This motor is more accurate.

Mapped Generator :

• This block is also similar like other blocks. Most of data required is taken from lookup tables corresponding to given input parameters.
• Therefore simulation time is less.

Dynamic Generator :

• This block involves user entering parameters manually during run time for their particular applications.
• The results taken time and are more accurate.

To Change Model From Mapped to Dynamic :

1. Open EV Model in Simulink
2. Enter Passanger car block in EV Model
3. Go to Electrical Plant block of Model
4. Inside that go to power train blockset.
5. Open motor block inside power train block
6. Then goto Modeling Tab and open Design drop down list box
7. Open Variant manager, where select Dynamic block.
8. Right Click and Select " Set as Lable Mode Active Choice ".
9. Then double click on " Gear Dynamic " title in Variant manager.
10. Then, This process can be represented for motor and Engine.

Q2. How does the model calculate miles per gallon? Which factors are considered to model fuel flow?

MPGe : MPGe is a US units is used to compare efficiency for gasoline vehicles with BEVs, PHEVs or FCEVs. MPGe unit Was formulated. MPGe stands for miles per Gallon equivalent. It has been found that 1 gallon of gas has same amount of energy as 33.7 kmh of electricity.

We should go inside EV referance block that is performance calculations :

Inside Performance Calculation block we will get actual mpg calculation.

Eg : A Battery propells that vehicle for 3.125 miles per kwh Capacity of battery. So 3.125 miles/kwh * 33.7 kwh/gallon = 105 MPGe.

In this model it is calculated by this blocks.

Here, Three differenct input are taken into considerations.

1. Vehicle Speed
2. Fuel Flow
3. Battery power

The Above image has Two fuels electricity and fuel. As Discussed earlier 1 Gallon of gas is equal to 33.7 kwh of electricity.

So that Battery power is first converted into kw (w/1000) then its divides by 33.7 kwh. Fuel Equivalent of battery is added to fuel flow.

Using Vehicle Speed and time distance of travel is calculated. then distance is converted into miles by conversitons.

Then as we have fuel folw in m^3 and distance in miles we can calculcate fuel efficiency.