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?
2. How does the model calculate miles per gallon? Which factors are considered to model fuel flow?
3. Run the HEV Reference Application with WOT drive cycle. Change the grade and wind velocity in the environment block. Comment on the results.
4. Keeping all other parameters same, compare the simulated results of hybrid and pure electric powertrains.

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

Powertrain Blockset provides two types of combustion engine models: mapped and dynamic.

Mapped Model of Engine	Dynamic Model of ENGINE
No subsystem are there, mostly lookup tables used.	Engine block are subsystem levels.
Used for analysis and design purpose only.	designing control operations also possible
Data for look up tables mapped from some design tool like GT-POWER.	Dynamic models are used real time component-level data.
These are used in for quasi steady-state engine simulations.	These are used to analyze the impact of individual engine components on the overall performance.
Mapped Model of Motor	Dynamic Model of Motor
The Mapped Motor block implements a mapped motor and drive electronics operating in torque-control mode. The output torque tracks the torque reference demand and includes a motor-response and drive-response time constant. Use the block for fast system-level simulations when you do not know detailed motor parameters, for example, for motor power and torque tradeoff studies. The block assumes that the speed fluctuations due to mechanical load do not affect the motor torque tracking.	To operate the dynamic model of motor we need the subsystem and detailed information of the motor such as current, voltage, frequency, efficiency, rpm etc, to perform the motor characteristics.
Mapped Model of Generator	Dynamic Model of Generator
Specifications for battery torque, battery current, motor torque are to be mentioned to obtain the results	A detailed specifications to be given as input to obtain the results and plots other than the mapped model of generator.

Steps to select the Model Type:

• Select the Model which you want to configure.
• Choose Variant Manager.
• Right Click the Model you wish to choose.
• Set as Label Mode Active Choice.

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

Miles per gallon

• Miles per Gallon is a fuel economy rating determined by how far a car can travel on a gallon of petrol or Diesel for a Engine powered car.

• 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 a important factor while considering the fuel consumption at that particular time,so to determine the fuel consumption throughout 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 covered 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 will result in the mass of the fuel and by using this 1 we convert it to the volume and by multiply by 1000 to get it in Litres.
• By comparing the two results we can get the amount of litre 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 power into energy by multiplying with the time into KWh.

Calculating Miles Per Gallon :

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

3. Run the HEV Reference Application with WOT drive cycle. Change 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 Internal combustion engine (ICE) system with an electric propulsion system
• The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional vehicle or better performance.
• Example of HEV is Toyota 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.

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 = 80 mph

Time to start deceleration = 50seconds

The Grade angle = 0 degrees

The wind velocity = 0 m/s

• The above figure shows the results for the simulation and there are totally six plots in them.
• Each plot shows a particular result and the plots are made in such a way that ,there is a cursor measurement and if we change the cursor on one plot the cursor moves on the otherplots too which paves way to study the result in a better 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 respect 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 speed of the Engine,motor and Generator in Rpm throughout the drive cycle.

Peak Engine speed = 4780 Rpm

Peak Motor speed = 9497 Rpm

Peak Generator speed = 13690 Rpm

plot 3:

Shows the Torque characteristics and its changes of engine,motor and generator in (Nm) throughout 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 values (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 charging to the battery = -150.86 A

Plot 5:

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

The state of charge decreased from 60% to 39.8% of charge 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 = 46 Miles,for the given vehicle at the specified driving conditions.

Case2

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 = 80 mph

Time to start deceleration = 50seconds

The Grade angle - 8 Degrees

The wind velocity = 10 m/s.

• In all the results we can observe some changes from the previous case
• Though the vehicle parameters and the drive cycle are the same ,here we have considered some changes in the environment blocks by adding some hill climb angles and wind 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 achieved as we have some additional forces 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 seconds

The deceleration time from 80 to minimum = 5.06 seconds

plot 2:

Shows the changes in speed of the Engine,motor and Generator in Rpm throughout the drive cycle.

Peak Engine speed = 4676 Rpm

Peak Motor speed = 8103.5 Rpm

Peak Generator speed = 12858.5 Rpm

plot 3:

Shows the Torque characteristics and its changes of engine,motor and generator 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 values (A) and its changes for various acceleration inputs as per the Drive cycle.

The peak current discharge 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 state of charge decreased from 60% to 25.98 % of charge 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 simulation results for both the cases is found and we can see that the simulation 1 without the inclusion of hill climbing conditions and the wind drag velocity is much more efficient when compared to the simulation which includes the hill climbing conditions and the wind drag velocity.
• The vehicle was not able to achieve 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 results of hybrid and pure electric powertrains.

Pure Electric Vehicle:

• A battery electric vehicle or pure Electric vehicle is a EV that exclusively uses chemical energy stored in rechargable battery packs with no secondary source of propulsion (e.g. hydrogen fuel cell, internal combustion engine, etc.) of energy.
• BEVs use electric motors and motor controllers instead of an conventional Internal combustion 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.

Case1

Simulation Condition:

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

The Total cycle time = 100 seconds

The Top speed of this cycle = 80 mph

Time to start deceleration = 50 seconds

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 108.9mph

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 Rpm throughout the drive cycle.

Peak Motor speed = 1123 Rpm

plot 3:

Shows the Torque characteristics and its changes of Motor in (Nm) throughout the drive cycle.

Peak Motor torque = 260 Nm

plot 4:

Shows the Battery Current values (A) and its 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 = -173.7 A

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 charge in a time period of 50.3 seconds , for the 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 electric vehicle however this gives equivalent battery energy required that of the fuel energy,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.

Case2

Simulation Condition:

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

The Total cycle time = 100 seconds

The Top speed of this cycle = 80 mph

Time to start deceleration = 50 seconds

The Grade angle = 8 Degrees

The wind velocity = 10 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 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 characteristics and its changes of Motor in (Nm) throughout the drive cycle.

Peak Motor torque = 280 Nm

plot 4:

Shows the Battery Current values (A) and its changes for various acceleration inputs as per the Drive cycle.

The peak current discharge from the battery = 225.8 A

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 decreased from 80% to 75.5% of charge in a time period of 49 seconds , for the 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 electric vehicle however this gives equivalent battery energy required that of the fuel energy,and calculates the Fuel efficiency.The maximum miles that the car can run per gallon of fuel equivalent = 21.45 Miles,for the given vehicle at the specified driving conditions.