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?

MAPPED MODEL- The mapped model is one type 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 requiered torque output just as required simply without considering the real time motor or engine, parameters

The output values are stored for the corrresponding 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 dyanamic model in other hand uses the combination of the outputs 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 individiual 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 that particuclar moment throught the drive cycle.

The accuracy of this model is very high as it considers the real outputs from all the subsystem to generate the output.

The simulation will take very long time to complete as it has so many individual simulations running by all the subsystem of the engine , motor/generator.

CHANGE THE MODEL TYPE-

In the powertrain blockset module we first need to select the vehicle type first wheather it is full electric , full engine or the type of hybrid vehicle.

After that the Simulink model appears by showing the work flow blocks of the model.

In that we need to go to Passenger Block Electric plant* EV Motor/Generator block.

After this just right click and go to Variance Label mode Active choice MotorGenEV Mapped or Dyanamic.

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

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 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

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.

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 the energy of equivalent LIS Gallons per seconds and we do this by dividing with 3600 and we convert the hour to seconds.

Then multiplying with 0.00378541 we convert the US Gallons per sec to the volume of the fuel flow in (mA3/ s) and then we multiply with 739 (California Phase Il Gasoline density) (i.e) mA3/s * kg/mA3 which gives the result as mass flow rate kg's.

Then finally 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 enegy and estimate the Miles per Gallons.

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

select the drive cylce then click on WOT option

and wind speed= and grad set as default

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.

2nd case

WOT with speed wind speed=10m/s and grad=8

when i decrese the simulation time upto 100

i get the clear graph

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 1The 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 EV-

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.

case 1

Ev refernce without changing wind speed and grad

case 2

wind speed =10m/s

grad=8

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 achievement .The electric vehicle produces more values of Motor speed and motor torque compared to the hybrid vehicle's motor alone,but hybrid vehicle when it combines the torque of both motor and its engine it is higher than the electric vehicle's torque.This is responsible to pull the Hybrid car at higher top speed compared to the pure electric.

2. As the pure electric car here uses Lithium-ion battery compared to the Nickel metal hydride battery the discharging capacity and the rate of charging is higher in the pure electric car. As it is able to discharge in a fast rate the motor can produce high amount of torque instantly compared to the hybrid vehicle. Also the state of charge shows the battery efficiency of the pure electric to be higher than the hybrid vehicle and this is also due to the battery type used in these cars.

3. The efficiency of the Electric car is higher than the hybrid car which is evident from the miles per gallon numbers of both of these cars.

4. Electric vehicle produces zero emissions whereas the hybrid one's produce waste gas emission.These are some of the observations from the comparision of the above simulations using Powertrain Blockset.