Week-4 Challenge WOT Condition Part-2
OBJECTIVES:
- To carry the analysis of HEV reference application with WOT drive cycle by changing the grade and wind velocity in environment block.
- From the above-HEV reference application keeping all parameters the same, simulated results from both HEV and electric vehicle are compared to draw conclusions based on the performance of both vehicles.
- The model calculates miles per gallon and factors to considered to model fuel flow.
- Difference between the mapped and dynamic model of engine, motor, and generator. Also to change model type.
HYBRID ELECTRIC VEHICLE REFERENCE APPLICATION FOR WOT DRIVE CYCLE
This is an HEV reference application for WOT drive cycle conditions(without any changes).
Since we are analyzing the HEV for WOT condition, The Drive cycle source is modified in such a way that its WOT condition by modifying all basic parameters such as WOT speed, deceleration time, and WOT simulation time as shown below.
Click on the "RUN" option in Simulink to carry out the above HEV simulation.
RESULTS:
The results from performance and FE scope give us 6 plots as shown below.
- PLOT 1- Target velocity vs actual velocity(mph)
The top speed of 89 mph was achieved at 24.4 seconds.
The deceleration from 89 mph to 0 takes 5.089 seconds.
- PLOT 2- Speed Curve plot for engine speed, motor speed, and generator speed(RPM)
This graph shows the speed of all 3 components (in RPM). The first engine graph curve is identical to the motor graph curve stating there are operating at the same speed.
- PLOT 3- Torque curve of the engine, motor, and generator(N-m)
Initially, Torque is offered by the motor until the battery is drained up to 171.5 Ampere after this Engine torque is offered to the vehicle to car out the acceleration. Since the battery is draining generator torque comes into action which leads to charging of the battery showing a negative Y-axis in the graph. The torque of the engine reduces gradually as the power increases due to the speed requirement of the vehicle.
- PLOT 4- Battery current(A)
Initially, the current required to run the motor is high and this reduces as the speed vehicle increases. The graph going on the negative axis shows its recharging.
- PLOT 5- Battery SOC(state of charge)
SOC initially is 80% as the vehicle accelerates to 89 mph SOC becomes 68.7%(due to discharging) hence change in SOC shows usage of the motor. At 54.83th second the generator is operated by recharging the battery since the battery is drained to 171.5 Ampere since the engine motor is running.
- PLOT 6- Fuel economy(MPG)
The fuel economy was high until a motor was used to accelerate the vehicle. If the power requirement of the vehicle increases then fuel economy decreases.
The maximum Fuel economy is 13.14 MPG.
The Minimum Fuel economy is 7.245 MPG
HYBRID ELECTRIC VEHICLE REFERENCE APPLICATION FOR WOT DRIVE CYCLE WITH CHANGE IN ENVIRONMENT
Here in This is an HEV reference application the drive cycle source is kept the same and there is a change in environmental parameters such as wind velocity and grade.
The grade value is set to 7.
The wind velocity in the x-direction is set to 10m/s.
All other parameters remain the same.
Click on the "RUN" option in Simulink to carry out the above HEV simulation.
RESULTS:
The results from performance and FE scope give us 6 plots as shown below.
- PLOT 1- Target velocity vs actual velocity(mph)
The top speed of 75 mph was achieved at 55.03 seconds.
The deceleration from 75 mph to 0 takes 3.724 seconds.
The maximum velocity is attained at 72.45mph for 7% gradeability and 10 m/s wind velocity for a given hybrid electric vehicle. Due to this, there is a difference in the graph of trace velocity and actual velocity as seen in the graph.
- PLOT 2- Speed Curve plot for engine speed, motor speed, and generator speed(RPM)
This graph shows the speed of all 3 components (in RPM). The first engine graph curve is identical to the motor graph curve stating there are operating at the same speed.
- PLOT 3- Torque curve of the engine, motor, and generator(N-m)
Initially, Torque is offered by the motor until the battery is drained up to 171.5 Ampere after this Engine torque is offered to the vehicle to car out the acceleration. Since the battery is draining generator torque comes into action which leads to charging of the battery showing a negative Y-axis in the graph. The torque of the engine reduces gradually as the power increases due to the speed requirement of the vehicle.
- PLOT 4- Battery current(A)
Initially, the current required to run the motor is high and this reduces as the speed vehicle increases. The graph going on the negative axis shows its recharging.
- PLOT 5- Battery SOC(state of charge)
SOC initially is 80% as the vehicle accelerates to 75 mph SOC becomes 67.89%(due to discharging) hence change in SOC shows usage of the motor. At 54.83 seconds generator since there is no usage of the motor-generator starts recharging the battery. Hence there are two different slopes.
- PLOT 6- Fuel economy(MPG)
The fuel economy was high until a motor was used to accelerate the vehicle. If the power requirement of the vehicle increases then fuel economy decreases.
The maximum Fuel economy is 7.7 MPG.
The Minimum Fuel economy is 7.245 MPG.
CONCLUSIONS:
Results are compared as shown in a spreadsheet.
https://docs.google.com/spreadsheets/d/1quBM-J0wQueF8R-Q2DwkFgxhD3gv4XO2VsMr-i6YMzo/edit?usp=sharing(Link for above spreadsheet)
Hence we can conclude that HEV has better performance when there is no change in wind velocity or gradeability. when there is a change in gradeability and wind velocity comes we can see that HEV for WOT condition whereas the vehicle speed applied at 40m/s(89mph) due to changes in both parameters leads to reduction of top speed to 75mph as shown in the table. The HEV has high fuel efficiency, better SOC, and high deceleration time.
ELECTRIC VEHICLE REFERENCE APPLICATION FOR WOT DRIVE CYCLE
Simulation of Electric vehicles with WOT without any change in their parameters.
Since we are analyzing the EV for WOT condition, The Drive cycle source is modified in such a way that its WOT condition by modifying all basic parameters such as WOT speed, deceleration time, and WOT simulation time.
RESULTS:
The results from performance and FE scope give us 6 plots as shown below.
- PLOT 1- Target velocity vs actual velocity(mph)
The top speed of 89.4 mph was achieved at 58.8 seconds.
The deceleration from 89.4 mph to 0 takes 8.27 seconds.
- PLOT 2- Speed Curve plot for motor speed, and generator speed(RPM)
This graph shows the speed of the motor at various points in RPM.
- PLOT 3- Torque curve of the motor, and generator(N-m)
This graph shows the torque offered by the motor which is drained till 60 seconds beyond this torque is negative which the battery is getting recharged.
- PLOT 4- Battery current(A)
The battery requirement (WOT condition) which is 213 Ampere remains constant then reduces to 100 amperes after this since the vehicle is the decelerating battery is recharged as shown in the graph.
- PLOT 5- Battery SOC(state of charge)
SOC initially is 80% as the vehicle accelerates to 89.4 mph SOC becomes 76.29%(due to discharging) hence change in SOC shows usage of the motor. At 58.8th second generator, since there is no usage of the motor, the generator starts recharging the battery.
- PLOT 6- Fuel economy(MPG)
The fuel economy was high until a motor was used to accelerate the vehicle. If the power requirement of the vehicle increases then fuel economy decreases.
The maximum Fuel economy is 46.54 MPG.
The Minimum Fuel economy is 24.04 MPG.
CONCLUSIONS:
HEV reference application keeping all parameters the same, simulated results from both HEV and electric vehicle are compared to draw conclusions based on the performance of both vehicles
Results are compared as shown in a spreadsheet.
https://docs.google.com/spreadsheets/d/1W57BTmIeUsC3aFASuMYKTxC5gO0OtPopY8lGe6aJOwc/edit?usp=sharing
By comparing both results of HEV and EV we can conclude
Both HEV and EV have the same SOC, EV provides high fuel economy compared to HEV, SOC of EV at end of acceleration and simulation almost remains same and Finally, deceleration time for EV is more compared to HEV.
The model calculates miles per gallon and factors to considered to model fuel flow
For electric vehicle
Factors considered to calculate the mile per gallon for an electric vehicle are vehicle speed and battery power. The vehicle speed is integrated to get the distance in meters. The value is converted to miles and kilometers. Battery power in watt is converted inti m^3 per gal which is then integrated and converted to US gallon and liter. The US gal value is used to divide the distance covered in miles to get the US MPG of the vehicle. Finally, the liter value is used to divide the distance covered in Km to get the L/100 Km of vehicle.
For hybrid electric vehicle
In HEV application factors considered to calculate the miles per gallon depends on parameters such as Vehicle speed, battery power, and fuel flow.
The vehicle speed is integrated to get the distance in meters. The value is converted to miles and kilometers. Battery power in watt is converted inti m^3 per gal which is then integrated and converted to US gallon and liter. Also, fuel flow integrated and added to battery power and converted m^3 to liter. The US gal value is used to divide the distance covered in miles to get the US MPG of the vehicle. Finally, the liter value is used to divide the distance covered in Km to get the L/100 Km of vehicle.
Difference between the mapped and dynamic model of engine, motor, and generator
Mapped model
Mapped mode(also known as a static model )l to carry out the simulation with predefined commands and a set of look-up tables. The mapped model takes less time compared to the dynamic model. In the mapped model it does not involve real-time outputs from the subsystems.
Dynamic model
The dynamic model involves real-time outputs from all the subsystems to simulate the model. By Considering all the subsystems, the accuracy of this model is better than a mapped model. Also for the dynamic model, it takes more time to simulate the model compared to the mapped model.
How to change the model
For an electric vehicle in Simulink model open electric plant block which is located inside the passenger car block. Right-click on the motgen mapped block, Next step to choosing the variant to the label mode of active choice which is MotgenEVmapped/MotgenEVdynamic.
For a Hybrid electric vehicle in Simulink model open electric plant block which is located inside the passenger car block. The model of motor and generator can be changed separately also to change model the type of the generator, right-click on the generator block. The next step is to choose the variant label mode of active choice which is MotgenEVmapped/MotgenEVdynamic. To change model the type of the Motor, right-click on the motor block then choose the variant label mode of active choice which is MotgenEVmapped/MotgenEVdynamic.