Week-4 Challenge WOT Condition Part-2

Week-4 Challenge WOT Condition Part-2

Task 1:

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

Mapped Model:

• A mapped model refers to the block where the inputs and outputs of the blocks are given in steady-state lookup tables to characterize system performance.
• The lookup tables provide input parameters and output parameters.
• A mapped model can only be used when we have the system data.
• The mapped model is used to study the effect of a factor on the simulation to the system level.

Dynamic Model:

• The dynamic model is a model which breaks down a system or a subsystem into its components.
• The combined output of these components is considered the output of the system.
• A dynamic model can be used when we have the component level data and the input data of each componenents
• It is used to study the impact of different components on the performance of the system.

Engines:

Mapped Engine model: It represents macro engine behaviours in the form of lookup tables such as Brake power, Torque, Engine efficiency, Emissions, etc at a specific instant of engine speed or engine load. It is used for quasi-steady-state engine simulations.

Dynamic engine model: In a dynamic engine model, the behaviour of individual engine components is analysed to study the engine dynamics. It is used to study the engine behaviour on a component level. The dynamic model is useful in designing control estimators and diagnostic algorithms that depend on dynamic subsystem states.

Motors

Mapped motors: A mapped motor represents the macro model motor behaviours as a set of lookup tables for parameters such as battery voltage, motor speed and torque in a specified condition. This model is used when we don't know detailed parameters such as the power and torque of the motor.

Dynamic motor: In a dynamic model we know the input parameters of the motor. This model provides accurate results, but the processing time is longer. This motor model uses a 3-Phase voltage source, PMSM, and interior PM controllers.

Generators:

Mapped Generator: A mapped generator is similar to a mapped motor where the input values such as battery voltage for generator block are predefined or a lookup table is used for that. Simulation time is less for a mapped generator.

Dynamic generator: In a dynamic generator the outputs are continuously calculated according to changes in input values with respect to the governing equations. Simulation time is more for a dynamic generator.

How to change the model type?

1. Enter the modelling options and enter the model explorer
2. Enter the passenger block ---> open Electric Plant ---> Open motor block
3. We can now see the mapped model "MotGenEvMapped" option is selected by default.
4. To change the model type right click on our preferences ---> a popup will be shown "set as label mode active choice"
5. Now the model type will be changed as "MotGenEvDynamic"

Task 2:

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

MPG or miles per gallon is a measure of fuel efficiency of a vehicle. It is the distance a vehicle can travel using a gallon of fuel.

In a Simulink model, the MPG is measured in a visualization block

Simulink model:

• In an HEV, the energy is used both from battery and fuel. So we need to add both battery and fuel energies after converting both the values into m3/gallon
• Battery power in W is converted to kW and then to kW/h
• By dividing it by a standard value33.7 we get US gallons per second.
• So now Wh is converted to Ws by dividing it by 3600
• The output is multiplied by a gain block by a factor of 0.00378541
• Now we have the same units for battery and fuel energy
• Now both values are added using add block
• Now this value is integrated to get the value of power at a particular second of time
• The square root of vehicle speed is found using the math function block
• The vehicle speed at a particular second is also found using the integrator block
• The speed value is multiplied by 0.00021371 to convert m to miles
• To convert m3 to gallons the fuel output is multiplied by 264.172
• Now the total miles travelled is divided by gallons of fuel used.
• This gives the MPG of the vehicle.