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?

Model and Dynamic subsystem of electric Motor/Generator:-

Mapped model :-

• The mapped model is one type of where the data points are pre-assigned in lookup tables.
• The engine or motor torque required is sensed and the motor or engine block generates the required torque output just as required simply without considering the real time motor or engine parameters.
• The output values are stored for the corresponding given input values of the engine, motor and generator.
• The accuracy of this type is not that high but the simulation will be done in much less time as it does not run by real time parameters

Dynamic model:-

• The dynamic model in other hand uses the combination of the output from various subsystems to generate the output.
• It runs by real time simulation where the required input from the drive cycle is taken and for that individual real time simulation gets performed and summing all the results of the subsystem gives the output for the simulation.
• As per the drive cycle requirements the initial bus voltage current is given along with the vehicle feedback so that it runs the actual simulation at the particular movement through the drive cycle.
• The accuracy of the model is very high as it considesr the real output from all the subsystem to the generate the output.
• The simulation will take very long time to complete as it has so many individual simulations running by aqll the subsystem of the engine, motor or genrator.
• The figure below shows the working phase of the dynamic model.

Steps to select the model Type:

1. In the powertrain blockset module we first need to select the vehicle first wheather it is full electric full engine or the type of hybrid vehicle.
2. After that Simulink model appears by showing the work flow blocks of the model.
3. In that we need to go to passenger block electric plant* EV motor/generator block.
4. After this just right click and go to variance label mode activate choice MotorGenEV mapped or Dyanamic.

2. How does the model calculate mile per gallon? which factors are consider to model fuel flow?

Miles per gallon:

• Miles per Gallon is a fuel economy rating determinined by how far a car can travel on a gallon of petrol or Diesel for a Engine powered car.
• In case of an electricvehicle it tells us the energy which is equivalent that of a engine powered car to people the car through adistance.
• The amount of fuel energy required to move a engine power car through a distance is determined and it is compared to the equivalent amount of electric energy required to move the car through the same distance and it is expressed as a mile per gallon.
• The powertrain block set has amodel that calculate the mile per gallon for all kinds of vehicle.

• The above model takes the input of the vehicle speed. Fuel flow and battery power to calculate the fuel consumption and the equivalent battery consumption and calculates the miles per gallon.

Vehicle speed and Fuel flow:

• The vehicle speed is aimportant factor while considering the fuel consuption at that particular time. So to determine the fuel consuption through out the drive cycle.
• To convert speed to distance we can Integrate with time and we are doing the same of converting the velocity to get distance coverd by integrating.
• Then the fuel flow is expressed as the mass flow rate(i.e) the amount of fuel at each moment in kg/sec. Now integrating this well result in the mass of the fuel and by using this one we convert it to the volume and by multiply by 1000 to get it in liters.
• By comparing the two results we can get the amount of liters consumed to run for 100km.

Battery power:

• The amount of Energy from battery power required to propel the vehicle Equivalent to that of the Engine is calculated here.
• The battery power is given in watts and it is converted to kw by dividing with 1000.
• Then we convert the Energy from kwh to equivalent energy in US gallon of automotive gasoline by dividing with 33.7 since we get the energy in US gallons equal in kwh we are trying to get energy of equivalents LIS gallon per second and we do this by dividing with 3600 and we convert the hours to seconds.
• Then multiplying with 0.00378541 we convert the US Gallon per second to the volume of the fuel flow in (mA3/s) and then we multiply with 739 (Califonia Phase Il Gasoline density) (i.e)mA3/s* kg/mA3 which gives the result as mass flow rate kg's.
• Then finelly the battery energy equivalent in kg/s is given as a input for the fuel flow parameter in order to find the equivalent US Gallons energy and estimate the Miles per Gallons.

Calculating Miles per Gallon:

• Then the input from the vehicle speed (i.e) the distance we found (in meters) is taken into the calculation and it is converting to the miles by multiplying with 0.000621371.
• Then the input from the fuel flow (Battery energy + Fuel energy) taken in mA3 and is converted into equivalent US Gallons by multiplying with 264.172.
• Then the two input miles covered and equivalent US Gallon is further divided and the result is got in Miles/Gallon.

3. Run the HEV Referance application with WOT drive cycle. Changed the grade and wind velocity in the environment block. Comment on the results.

Hybrid Electric Vehicle:-

• A hybrid electric vehicle (HEV) is a type of hybrid type that combines a conventional Intrenal combution engine (ICE) system with an electric propultion system.
• The presence of the electric powertrain is intended to achive either better fuel economy than a conventional vehicle or better performance.
• Example of HEV is Toyata Prius.

• In the powertrain blockset we have selected the hybrid electric vehicle and this is the simulink model.
• Here we can select the input parameters as we wish and we can Run the simulation to check the results.

Case1

Simulation condition:

The simulation is done for Hybrid electric vehicle with Wide Open Throttle Drive cycle. The total cycle time = 100 seconds

The Top speed of this cycle = 80mph

Time to start deceleration = 50 seconds

The Grade angle = 0 degrees

The wind velocity = 0 m/s

• The above figure show the result for the simulation and there are totally six plots in them.
• Each plot shows a particular results and the plots are made in such a way that there is a cursor mesurment and if we change the cursor on one plot the cursor moves on the other plots too which paves way to stedy the result in a batter way.
• the cursor enables us to study the behaviour of other result parameters corresponding to the acceleration of the vehicle .

plot 1:

Shows the velocity of the vehicle with rspect to the Drive cycle data with the Time scale on the x axis.

The acceleration time to reach 80 mph - 16.7 seconds

The deceleration time from 80 to minimum = 6.2 seconds

plot 2:

Shows the changes in the speed of the Engine, motor and genarator in RPM through out the drive cycle.

peek engine speed = 4780 RPM

peak motor speed = 9497 RPM

peak generator speed = 13690 RPM

plot 3:

Shows the torque charecterstics and its changes of engine, motor and generator in (Nm) through out the drive cycle .

Peak engine torque = 138.7 Nm

Peak motor torque = 206.7 Nm

Peak generator torque = 42.2 Nm

plot 4:

Shows the battery current value (A) and its changes for various acceleration inputs as per the drive cycle.

The peak current discharge from the battery = 163.5A

The peak current charge to the battery = -150.8A

plot 5:

Shows the battery state of charge SOC(%) and it's changes corresponding to the driveing inputs.

The state of charge decreased from 60% to 39.8% of charge in the time period of 49.3 seconds for the specified driving conditions.

plot 6:

Shows the Fuel Economy as Mile per gallons for the corresponding inputs driving conditions.

The maximum miles that the car can run per gallon of fuel equivalent = 46 miles for the given vehicle at the specified driving conditions.

Case 2:

Simulation condition:

The simulation is done for the Hybride electric vehicle with Wide Open Throttle Drive cycle.

The Total cycle time = 100 seconds

The top speed of this cycle = 80 mph

Time to start deceleration = 50 sec

The grade angle = 8 degrees

The wind velocity = 10 m/s.

• In all the result we can observe some changes from the previous case.
• Through the vehicle parameters and the drive cycle are the same here we have considered some changes in the environment block by adding some hill climb angles and wide velocity.
• The changes in the results are given below.

plot 1:

Shows the velocity of the vehicle with respect to the drive cycle data with the time scale on the x axis.

The top speed of 80 mph cannot be achive as we have some additional force acting and so the car can only run upto 67.2 mph

The acceleration time to reach top speed of 67.2 mph = 44.5 sec

The deceleration time from 80 to minimum = 5.06 seconds

plot 2:

Shows the changes in the speed of the Engine , motor and Generator in the RPM through the drive cycle.

Peak Engine speed = 4676 RPM

Peak Motor speed = 8103.5 RPM

Peak generator speed = 12858.8 RPM

plot 3:

Shows the torque charecterstics and it's changes of engine motor and genaretor in (Nm) throughout the drive cycle.

Peak Engine torque = 139.6 Nm

Peak Motor Torque = 206.4 Nm

Peak Generator torque = 48.2 Nm

plot 4:

Shows the battery current value (A) and it's changes for various acceleration inputs as per the drive cycle .

The peak current dicharge from the battery = 167.6A

The peak current charging to the battery =-152.46 A

plot 5:

Shows the battery state of charge SOC(% ) and its changes corresponding to the driving inputs.

The stste of charging from 60% to 25.98% of charging in a time period of 49.3 seconds for the specified driving conditions.

plot 6;

Shows the fuel economy as mile per gallons for the corresponding input driving conditions.

The maximum miles that the car can run per gallon of fuel equivalent = 17.93 Miles for the given vehicle at the specified driving conditions.

Observation:

• The vehicle was not able to achive the required top speed though using the highest possible current discharge of that same battery used before.
• The state of charge also shows that the discharge is also high compared to the simulation 1.
• The fuel economy is also down to half of the previous simulation.
• So one can say it is evident that the efficiency of no load vehicle is high compared to the vehicle with additional loads acting on them and also we have visualized this using the powertrain blockset.

4. Keeping all other parameters same Compare the simulated result of hybrid and pure electric powertrains.

Pure Electric Vehicle:

• A battery electric vehicle or pure Electric vehicle is a exclusively uses chemicle energy stored in rechargeble packs with no secondary source of propulsion (e.g. hydrogen fuel cell internal combution engine etc ) of energy.
• BEVs use electric motor and motor controllers insted of an conventional Internal combution engines for propulsion. They derive all power from battery packs.
• So they don't produce any emission of waste gas and they are eco friendly.
• they also have their own limitations such as range etc.
• example of pure EV is NISSAN LEAF.

• Now comparing both the pure electric and Hybrid electric vehicle with the given conditions in a simulation to observe the behaviour of both the type.

Case 1:

Simulation conditions:

The simulation is done for pure electric & Hybride vehicle with Wide Open Throttle (WOT) Drive cycle.

The Total cycle time = 100 sec

The Top speed of this cycle = 80 mph

Time to start deceleration = 50 sec

The Grade angle = 0 degrees

The wind velocity = 0 m/s

plot 1:

Shows the velocity of the vehicle with respect to the Drive cycle data with the time scale on the x axis.

The top speed of 80 mph cannot be achieved as we have some additional forces acting and so the car can only run upto 108.9 mph

The acceleration time to reach top speed of 108.9 mph = 50.2 seconds

The deceleration time from 80 to minimum = 9.8 seconds

plot 2:

Shows the changes in speed of the motor in the RPM throughout the drive cycle.

peak motor speed = 1123 RPM

plot 3:

Shows the torque charecterstics and its changes of Motor in (Nm) through the drive cycle.

peak motor torque = 260 Nm

plot 4:

Shows the battery current values (A) and it's changes for various acceleration inputs as per the drive cycle.

The peak current discharge from the battery = 216.8 A

The peak current charging to the battery =-173.7A

plot 5:

Shows the Battery state of charge SOC(%) and its changes corresponding to the driving inputs .

The state of charge decreased from 80% to 75.5% of charging in a time period of 50.3 seconds for specified driving conditions.

plot 6:

Shows the equivalent fuel economy as mile per gallons for the corresponding input driving conditions. Here there is no fuel in pure vehicle however thos gives equivalent battery energy required that of the fuel enrgy and calculates the fuel efficiency. the maximum miles that the car can run per gallon of fuel equivalent = 20.45 miles for the given vehicle at the specified driving conditions.

Case 2:

Simulation conditions:

The simulation is done for pure electric & hybrid electric vehicle with Wide Open Throttle (WOT) Drive cycle.

The total cycle time = 100 sec

The top speed of this cycle = 80mph

Time to start decleration = 50 sec

The grade angle = 8 degrees

The wind velocity = 10 m/s.

plot 1:

Showing the velocity of the vehicle with respect to the drive cycle data with the Time scale on the x axis.

The top speed of 80 mph cannot be achive as we have some additional forces acting and so the car can only run upto 58.9mph

The acceleration time to reach top speed of 58.9 mph = 48.8 seconds

The deceleration time from 80 to minimum = 4.63 seconds

plot 2:

Shows the changes in speed of the motor in RPM throughout the drive cycle.

peak motor speed = 6254 RPM

plot 3:

Shows the torque charecterstics and it's changes of motor in (Nm) throughout the driving cycle.

Peak motor torque = 280 Nm

plot 4:

Shows the battery current value (A) and its changes for various acceleration inputs as per the drive cycle.

The peak current discharge from the battery = 225.8A

The peak current charging to the battery =-163.7 A

plot 5:

Shows the battery state of charge SOC(%) and its changes corresponding to the driving inputs.

The state of charge decreases from 80% to 75.5% of charge in a time period of 49 sec for the specified driving conditions.

plot 6:

Shows the equivalent fuel economy as mile per gallons for the corresponding input driving conditions. here ther is no fuel in pure electric vehicle however this gives equivalent battery energy required that of the fuel energy calculates the fuel efficiency. the maximum miles that the car can run per gallon of fuel equivalent = 21.45 miles for yhe given vehicle at the specified driving conditions.

Observation(Pure Electric VS Hybrid Vehicle With Same Load Conditions):

1. The electric vehicle when compared with hybrid electric vehicle with the same environmental and Drive cycle conditions results in less top speed achivement.
2. aAs the pure electric car here uses Lithium-ion battery compared to the Nickel Metal hydride battery the discharge capacity and the rate of charging is higher in the pure electric car.
3. The efficiency of the Electric car is higher than the hybrid car is evident from the miles per gallon numbers of both of these cars.
4. Electric vehicle produces zero emission whereas the hybrid one's wast gas emission. these are some of the observations from the comparesion of the above simulations using powertrain blockset.