Week-4 Challenge WOT Condition Part-2

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

Ans:

Objective: To present the difference between the mapped and dynamic models at a given state.

A. Some features of a mapped model:

Definition: The model that uses a steady-state lookup table to characterize either engine, motor or generator is known as 'Mapped Model'.

Application: In quasi steady-state simulation.

Other: 1. The output which we get is based on the set of data that we have stored in look-up tables.

2. Less time is required to complete a simulation.

3. But the disadvantage is it is not that accurate.

B. Some features of a dynamic model:

Definition: The model that separates its behavior as an engine, motor, or generator that is further separated into low-level components which is useful to capture the dynamic effect is known as 'Dynamic Model'.

Application: When a component level analysis is required. It helps to gauge the individual performance against overall performance.

Other: 1. The output which we get is based on the individual component.

2. This type is more accurate.

3. But the disadvantage is it requires more time for performing a simulation.

C. How can you change the model type?

1. Select the required vehicle type

2. Go to 'Passenger block'

3. Go to 'Electric plant block'

4. Go to 'Engine plant block'

5. Go to Variant

6. Do Label mode active

7. Select the required mode.

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

Ans:

Objective: To state the calculation of Miles per gallon and factors for modeling the Fuel flow.

A. Calculating the Miles per gallon:

Below mentioned is the performance calculation block that calculates the Miles per gallon in Visualization.

The above block takes the inputs as:

1. Vehicle Speed

2. Fuel Volume Flow

3. Battery Power

We will take a closer look on all of them below.

A. Vehicle Speed:

• The input of vehicle speed is being splited by two equivalent values and product the values.
• Then, again take square root of values from the output of product that will have the same answer.
• Integrate that output values and record the results in terms of meter.
• Now, use the math to convert meter into kilo-meter.
• The output value after saturation of FuelVol Flow and Vehicle Speed is multiplied and divided in the same block as this.
• Lastly, it will show output as Milege for distance covered as 100km.

B. Fuel Volume Flow:

• Add two inputs and the value of fuel volume flow.
• The output of the addition is obtained.
• Use an integration block for getting output in meter cube.
• For calculating the fuel consumption of vehicle, the output is being converted into Litre.

C. Battey Power:

• Firstly, convert the watts into kilo-watts in order to receive the output.
• Then, take the output per hour to 'US EPA' standard as shown in the block mentioned above.
• Divide that with 33.7.
• Then, convert these values into seconds.
• So, now the output will be in-terms of Kws/USgal.
• At last, volume of fuel flow is obtained in meter cube per gal.

Above mentioned is the Model for calculation of Miles per gallon.

C. Factors involved are as below:

1. Vehicle Speed

2. Fuel Volume Flow

3. Battery Power

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

Ans:

Objective: To run the HEV Reference Application with WOT Drive Cycle with given conditions and record the results.

A. HEV Reference Example (Toyota):

Below mentioned shows the path for HEV energy transmission:

B. HEV Model of a Powertrain Blockset:

Below mentioned is the Simulink model in the Powertrain Blockset:

Fundamental Blocks:

1. Reference signal

2. Longitudinal Driver

3. Controllers

4. Passenger Car

5. Environment

C. Parameters Used for reference HEV:

The parameters used for the 1st case are as follows:

D. Environment Block Sub-system:

Below mentioned is the sub-system of the environment block used in HEV example in Simulink:

E. Results:

The results include the following sub-graphs as depicted in the above figure:

1. Trace Velocity

2. Engine Speed, Motor Speed, and Generator Speed

3. Engine Torque, Motor Torque, and Generator Torque

4. Battery Current

5. Battery SOC

6. Fuel Economy Curve

So, these all graphs are without changing the Grade and Wind values. Below we will do it with the change of both.

F. Environment Block Sub-system (With the change in Grade and Wind value):

G. Results (With Change):

H. Conclusions:

1. Simulation results of the model without the inclusion of Grade and Wind are efficient than that of with the inclusion of Grade and Wind.

2. Because of more wind and grade, the battery SOC is less in with change cases as compared to the first one that is without the inclusion of wind and grade.

3. The graph of the fuel economy shows that with the grade and wind; the fuel economy is down to almost 50%.

4. So all and all it is clear that the real-time scenario i.e. with the addition of grade and wind, the vehicle is less efficient than before their inclusion.

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

Ans:

Objective: To compare HEV and EV powertrains.

A. EV energy transmission routes:

The below figure depicts the transmission rote for a pure EV.

B. EV Reference Model in Simulink:

As mentioned above all the fundamental blocks remains the same in case of an EV as that of a HEV.

C. Results:

The results include the same graphs as HEV but the behavior is different.

D. Comparison of EV and HEV:

1. EV produces more individual motor speed as well as motor torque than HEV.

2. But, for combined torques of motor and engine, HEV produces more torque than EV.

3. Because of the above mentioned reason, HEV attains more top speed than EV.

4. The rate of discharge is more in the case of EV than HEV as the batteries used vary for both the vehicles.

5. EV produces almost zero emissions theoretically as compared to the HEV.

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