Week-4 Challenge WOT Condition Part-2

1. Open EV reference application model. Under the visualisation block, we can see various blocks used for calculation.
   
   
2. Open performance calculation block, which has vehicle speed and battery power as inputs.
   
   
3. MPG is different from MPGe. MPGe means miles per gallon equivalent. MPGe is calculated in the model with the help of battery power, Fuel volume flow and vehicle speed.
4. Here vehicle speed is multiplied itself and them square rooted. The value is then integrated(1/s) and converted into meters (m) is converted into miles in the block (m to mile) then it is divided by US Gal to get US MPG.
   
   
5. Battery power is divided by 1000 and then divided by 33.7. Then it is converted to s per hour and then converted to m^3 per gal.
   
   
6. The value is finally converted into gallons and used as MPG after dividing miles with a gallon.
   
   

Factors considered in model fuel flow:-

1. Battery power capacity should be high and vehicle power consumption should be low for higher MPGe
2. Vehicle speed

Q3. Run the HEV ReferenceApplication with WOT drive cycle. Change the grade and wind velocity in the environment block. Comment on the results.

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.

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

• Mapped motor and generator
• 1.5–L spark-ignition (SI) dynamic engine

Diagram of HEV:-

HEV Reference Application Model:-

Description:

1. Open HEVReference application made in MATLAB.
2. It contains various subsystems like environment, logitudinal driver, passenger car, visualisation etc.
3. By default it is FTP75 drivecycle with 2474 seconds.

Case 1

The default drive cycle is FTP75 with 2474 sec, Now change it to WOT drive cycle with WOT simulation time as 100 sec.

Results:

1. The current increases initially up to 500 and decrease at 18 seconds. It increases for some seconds and goes negative after 20 seconds.
2. After 25 seconds, the current becomes constant.
3. The RPM increases and decreases up to 25 seconds. The peak RPM is around 8500.
4. The battery SOC decreases from 80 to 72. After 20 seconds there is a little amount of increase when the engine works.
5. Engine torque increases initially and goes negative after 20 seconds. The peak torque achieved is around 275.
6. The fuel economy increases continuously up to 16.

Case 2:-

Now changing the environment sub-system in case 1 specification of HEV reference application. The grade was now changed from 0 to 10 and wind velocity from 0 to 5.

Result:-

1. At 20 seconds, the current becomes negative. Battery current is same when compared with above condition.
2. The RPM is positive and doesn't go too negative.
3. Due to grade and wind velocity, the SOC decreases more due to the more required power. It falls below 72 slightly less SOC than the previous condition.
4. Torque is same as previous condition.
5. Due to HEV, the fuel economy increases only upto 10. This is less when compared with previous condition.
6. We can observe that battery current increased upto around 500 and changes occurs.

Q4.Keeping all other parameters the same, compare the simulated results of hybrid and pure electric powertrains.

EVReferenceApplication:-

1. Open EVReferenceApplication.
2. It consists of drive cycle, environment, logitudinal driver, controller, passenger car and visuals subsystem.
3. Open the environment subsystem and change grade as 5 and wind velocity as 10.
4. Run the simulation with 2474 seconds.

Model:-

Results:-

1. First plot shows, the drive cycle.
   
   
2. Second plot shows battery SOC. The battery decreases and increases throughout the drive cycle. When it reaches to 70% the engine produces power and the vehicle is run. It charges for some time upto 80% and continuously goes on throughout the drivecycle. During deceleration the battery charges.
   
   
3. Third plot shows motor speed and engine speed. One speed is almost lower than other times.
   
   
4. Fourth plot shows the battery current. It increases and decreases continuously throughout the drive cycle.
   
   
5. Fifth plot shows motor torque, engine torque and generator torque.
   
   
6. Sixth plot shows US fuel economy. Initially, it increases upto 28 and maintains almost constant. It decreases and increases around 10. It is almost constant after 250 seconds.

Conclusion:-