Week-4 Challenge WOT Condition Part-2

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

Difference between mapped and dynamic model of Engine:

Difference between mapped and dynamic model of Motor:

Difference between mapped and dynamic model of Motor:

The below chart shows the difference between Mapped and Dynamic Models and also the Effects on Component or Parts for Simulation 

How can you change model type:

After entering into passenger Block then we need to go into Electric plant then into motor there we find MotGenEvMapped and MotGenEvDynamic, MotGenEvMapped is by default selected as a model type for motor.

• To change from MotGenEvMapped to MotGenEvDynamic
• First we open our reference model into Matlab

Here we are choosing EV as an example

Then after clicking on the modeling section and after that in design block, we will select the variant manager option. After the Variant manager window gets opened.

Then by clicking on the passenger car expand option there will electric plant option that will expand and that will get both battery and motor

We are taking motor as an example 

Then after expanding the motor option we will get

• MotGenEvMapped 
• MotGenEvDynamic

So that default one in MotGenEvMapped that is changed into MotGenEvDynamic

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

Theory:

 Miles per gallon gasoline equivalent is a measure of the average distance travelled per unit of energy consumed. MPG is used by the United states Environmental Protection Agency (EPA) to compare energy consumption of alternative fuel vehicle , plug in hybrid electric vehicle and other advanced technology vehicles with the energy consumption of conventional IC vehicles rated in miles per U.S.gallon

 The unit of energy consumed is deemed to be 33.7 Kw without regard to the efficiency of conversion of heat energy into electrical energy, also measured in kilowatt hours. The equivalence of this unit to energy in a gallon of gasoline is true if and only if the heat engine, generating equipment, and power delivery to the car battery are 100% efficient. Actual heat engines differ vastly from this assumption.

The EPA gives each Vehicle three different MPG ratings, as all car leasing notes

• Highway MPG: the average a car will get while driving on an open Stretch of road without stopping or starting, typically at a higher speed.
• City MPG: the Score a car will get on average in city conditions,with stopping and starting at lower speeds.
• And the Combined MPG, a combined average of highway and city MPG 

MPG does not necessarily represent an equivalency in the operating costs between alternative fuel vehicles and the MPG rating of internal combustion engine vehicles due to the wide variation in costs for the fuel sources regionally since the EPA assumes prices that represents the national averages. Miles per gallon equivalent cost for alternate fuel can be calculated with a simple conversion to the conventional MPG. See conversion to MPG by cost below 

Formula for the Miles per Galon

Model calculate miles per gallon:

      To calculate the fuel flow, Vehicle speed and battery power are taken into consideration and in Hybrid Electric Vehicle model has Separate blocks to calculate the MPG that has Shown below.

          Inside the Performance Calculation block.

• In the above MPG Calculation is for HEV which means it contains both Fuel and the battery energy
• In the battery , the Power in watt Which is converted into Kwatt and further converted into Kw/hr.
• Then it is Converted into US gallon equivalent energy by dividing it by the standard value 33.7. Then Converted into US gallons per Second.
• It is multiplied by standard value 0.00378541 to get volume in meter cube per gallon and it is added to tht fuel flow for Total value as in Hybrid Electric Vehicle
• Then meter Cube is Converted into US gallon
• At last, the speed of the Vehicle is integrated to get distance Which is in the meter is Converted into mile by Multiplying the Standard Value with 0.000621371.
• Finally we get US MPG Value

Fuel Consumption Vs Fuel economy: 

      Fuel consumption and fuel economy are two phrases that are sometimes used interchangeably but have very different meanings. The core difference involves fuel consumption discussing how much fuel a car consumes to go a certain distance and fuel economy measures how much distance a car gets out of fuel. Therefore, they have an inverse relationship While the meanings are similar, there is a slight difference worth noting . Fuel Consumption measures the amount of fuel a car consumes to go a specific distance. It is expressed in litres—or in countries that use the imperial system, miles per 100 gallons. For example, a Volkswagen Golf TDI BlueMotion has one of the best fuel consumption ratings, requiring just 3.17 litres to go 100 Kilometers. Therefore, the smaller the value, the better the rating is.

Fuel economy is measured in miles per gallon (or in electric Vehicle, Miles per Galon equivalent(MPG), and refers to how far a car can go using a set amount of fuel. Since this is the inverse of fuel consumption, the larger the value, the better the rating. Sometimes, the term fuel efficiency is used. Its important to note that this is a colloquial term which is used in place of fuel economy. However, a true fuel efficiency should be expressed by a percent which measures how much of the fuel is used to power the movement of the car, vs the total amount of fuel that was injected.

factors are considered to model fuel flow:

• Vehicle Speed
• Battery Power
• Fuel Flow

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

Step1:

        First, we need to open reference HEV application.Then hybrid electric vehicle reference application represents a full multimode hybrid electric vehicle (HEV) model with an internal combustion engine, transmission, battery, motor, generator, and associated powertrain control algorithms. Use the reference application for powertrain matching analysis and component selection, control and diagnostic algorithm design, and hardware-in-the-loop (HIL) testing. To create and open a working copy of the hybrid electric vehicle reference application project and enter into it.

By default, the HEV multimode reference application is configured with

This diagram shows the powertrain configuration.

Step2:

  After Clicking on the HEV Reference Application file

           autoblkHevStart

we directed to our Matlab window after reading the files inside that application we directed towards our HEV modeling section.

Step3:

   Double -clicking on the drive cycle block then Block Parameter block open, then change drive cycle source into Wide open Throttle.

  Also Change Speed, time, acceleration and Simulation time by changing the Drive cycle

Step4:

  We are going to enter our simulation stop time program execution type on accelerator mode and then hit run to Simulate the results.

    If the Grade and wind is zero then the Emission calculation is shown below

Step5:

Now we will change the grade Value and Wind in the X-direction in the environmental block to see a difference in results.

And keeping all other condition are same and running simulation for one more time.

We got these graph,

If the grade value is 5 and wind is 45 then the Emission Calculation is shown below

So we are going to write an observation about this graph.

Graph1: Trace Velocity Vs Actual Velocity

            The Violet line indicates the trace velocity and the Orange line indicates the actual velocity by referring actual velocity line here we can see the vehicle requires from 2Sec to 20Sec time to achieve the maximum speed towards the targeted path by using battery power on after that Vehicle starts to deaccelerate.

Graph2: Engine motor Vs Generator Speed

             As the battery is fully charged, at initial condition, only the motor speed is used which high at starting because of resistance due to slope and wind velocity, the engine speed is overlapped with generator speed indicating both running  on the same RPM, initial there is no need for the engine and generator speed as the motor is fulfilling the requirement to achieve the maximum speed of the vehicle.Therefore they are at 0 Pm but when the battery will discharging or when the state of charge(SOC) becomes below 70% then the only engine will start to rotate to provide and maintain the speed of the vehicle and so far generator will also start to charge the battery at the same time hence their rpm are the same.

Graph 3: Engine torque, Motor Torque and generator torque.

              As the battery is being used at the Start, So torque will also maximum for the motor in this case until case until the vehicle acquires its maximum speed. Once the Vehicle reached at constant speed the torque requirements will reduce.Here also when there is deacceleration, the torque value becomes constant once the battery goes into charging state cause now.Here engine torque is being used due to below 70% SOC. Also, generator torque will be negative indicating that electric motor is charging and in this period engine has to overcome the torque requirement of vehicle successfully.

Graph4: Battery Current

            When a vehicle uses an electic motor then only it is used to generate the power of the motor, When the vehicle accelerates then there is no current is extracted to produce power for the motor.From the graph you also can see, the current requirement becomes stable when the battery charging mode is activated.  

Graph 5:(State of Charge)

           SOC is very important for battery-driven vehicles. From the graph it can be seen that the battery is used below 80% the state of charges goes down and the battery goes on charging mode through generator once the battery gets charged then its state of charge also increases and it won't fall down until battery is subjected to another operation.

Graph6:MPGE

       The graph show miles per gallon equivalent to run the vehicle during the higher speed the fuel need is high as the vehicle deaccelerate the fuel requiremeent is less.

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

Hybrid Electric Vehicle Multimode Reference Application:

    The hybrid electric vehicle reference application represents a full multimode hybrid electric vehicle (HEV) model with an internal combustion engine, transmission, battery, motor, generator, and associated powertrain control algorithms. Use the reference application for powertrain matching analysis and component selection, control and diagnostic algorithm design, and hardware-in-the-loop (HIL) testing. To create and open a working copy of the hybrid electric vehicle reference application project, enter

autoblkHevStart

By default, the HEV multimode reference application is configured with:

This diagram shows the powertrain configuration.

This table describes the blocks and subsystems in the reference application, indicating which subsystems contain variants. To implement the model variants, the reference application uses variant subsystems.

autoblkHevStart

If we run the simulation file 2474 sec under the drive cycle Source of FTP75.

From the above graph Trace Velocity is actual drive cycle source the Engine speed, Motor speed, generator speed actually it follow the drive cycle Velocity source if the drive cycle more speed is more likewise if drive cycle velocity is low speed is low and Motor torque perform based on the load.Battery current and Battery Soc Charges and discharge based on the load

Electric Vehicle Reference Application:

          The electric vehicle reference application represents a full electric vehicle model with a motor-generator, battery, direct-drive transmission, and associated powertrain control algorithms. Use the electric vehicle reference application for powertrain matching analysis and component selection, control and diagnostic algorithm design, and hardware-in-the-loop (HIL) testing. To create and open a working copy of the conventional vehicle reference application project, enter

autoblkEvStart

The electric vehicle reference application is configured with a mapped motor and battery. This diagram shows the powertrain configuration.

This table describes the blocks and subsystems in the reference application, indicating which subsystems contain variants. To implement the model variants, the reference application uses variant subsystems.

autoblkEvStart

If we run the simulation file 2474 sec under the drive cycle Source of FTP75.

• The one of the Important or main difference in the EV and HEV is Power Source and also in HEV uses the battery and engine Si/Ci, While Ev uses only the Battery.
• If Velocity gradually follow the Motor speed and the torque depend on type of load such as Vehicle Weight etc.And this was Shown in above graph.
• While accelerating we required more torque which collected by using the motor. So SOC decreases after sometime the Vehicle will run on the engine .So fuel economy decreases and SOC gradually increases.