Week-4 Challenge WOT Condition Part-2

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

Ans : The difference between mapped and dynamic model of engine, motor and generator is mapped model is where data point are pre define in lookup tables. The engine, motor and generator torque required sensed and the engine, motor and generator block generates the required torque output just as required without considering the real time engine, motor and generator parameters.

The dynamic model is combinations of various subsystems to generates the output. Its based on real time simulation considering real time engine, motor and generator parameters. Accuracy of dynamic model is high as compare to mapped model.

The model can change simply right click on MotGenEV block select variant and change model type according to requirement

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

Ans : The powertrain blockset has a model thats calculate model miles per gallon.

• The factors are considering model fuel flow is Vehicle speed, Fuel volume flow and Battery power

• First vehicle speed convert into distance by integrating with time. Then fuel flow is integrating and convert into volume & by multiply by 1000 to get it in liters.

• By comparing this two results we can get the amount of litre consumed to Run for 100km.
• The power is converted to kw by dividing with 1000. Then we convert power into energy by multiplying with the time into KWh.
• Then we convert the energy from KWh to equivalent energy of by dividing US EPA 33.7. after that convert hrs to sec by dividing 3600.
• Then multiply with 0.00378541 we convert US gallon per sec to volume of fuel flow m^3 per gallon. this ouput is given to input of battery energy equivalent.
• The last step is input from vehicle speed i.e. distance is converted to by multiplying with 0.000621371. then the input from fuel flow is converted into US gal by multiplying 264.172
• The two inputs miles converted and equivalent US gallon iss further divided and result got in Miles / Gallon.

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

Ans : The simulation model HEV ReferenceApplication are following

• Select drive cycle to Wide open throttle.
• Add nominal reference speed 80, time to start decelration 50 and WOT simulation time is 100sec
• Run simulations for 100sec without changing environmental parameters and see result.

With changing environmental parameters

Gradability = 10 and Wind Velocity = 10m/s

Parameter	Without Changing Environmental Parameter	With Changing Environmental Parameter
Max. Velocity(mph)	113	61
Max. Engine Speed(RPM)	5464	5447
Max. Motor Speed(RPM)	13723	8924.58
Max. Generator Speed(RPM)	5464	5445
Max. Engine Torque(Nm)	174.7	174.9
Max. Motor Torque(Nm)	300	300
Max. Generator Torque(Nm)	169.6	169.6
Max. Current(A)	512.1	522.7
Max. SOC(%)	80	80
Min. SOC(%)	62	62
Max. Fuel Economy MPGe	12.35	5.83

Results : We can see that by comparing Without Changing Environmental Parameter and With Changing Environmental Parameter the vehicle not able to achieve the required speed though using the highest possible discharge with same battery used before. Similarly fuel economy aslo reduces to half of the previous simulation. So efficiency of no load vehicle is high as compared to the vehicle with additional loads.

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

Ans :

Pure EV simlulation results

Parameter	Pure EV with load	HEV with load
Max. Velocity(mph)	51	61
Max. Engine Speed(RPM)	-	5447
Max. Motor Speed(RPM)	5482	8924.58
Max. Generator Speed(RPM)	-	5445
Max. Engine Torque(Nm)	-	174.9
Max. Motor Torque(Nm)	279.94	300
Max. Generator Torque(Nm)	-	169.6
Max. Current(A)	225.70	522.7
Max. SOC(%)	80	80
Min. SOC(%)	75.50	62
Max. Fuel Economy MPGe	18.46	5.83

Result : The Pure EV vehicle compare with HWEV with same load conditions results in less top achievement in EV. The HEV produce more speed and torque as compare to EV. As the pure EV able to min SOC is low value as compare to HEV. The efficiency of the EV is higher than the hybrid vehicle from the miles per gallon numbers of both vehciles.