Week-4 Challenge WOT Condition Part-2

AIM:- To study wide open throttle condition for HEV'S and EV's

OBJECTIVES:-

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

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

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

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

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

For Engine:-

Type		Implementation	When to Use
Mapped	CiMappedEngine SiMappedEngine	Model uses a set of steady-state lookup tables to characterize engine performance. The tables provide overall engine characteristics, including actual torque, fuel flow rate, BSFC, and engine-out exhaust emissions.	If you have engine data from a dynamometer or a design tool like GT-POWER. For quasi steady-state engine simulations.
Dynamic	CiEngine SiEngine	Model decomposes the engine behavior into engine characteristics that are separated into lower-level components. By combining components in this way, the models capture the dynamic effects.	If you need a more detailed dynamic model and have component-level data. To analyze the impact of individual engine components on the overall performance.

For motor:-

Type	Implementation
Mapped 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.
Dynamic motor	1) The DC motor circuit diagram is represented. 2) The system equations are created. 3) The transfer function is calculated. 4) Then the model block diagram is prepared. 5) The is done to simulate the model in programming MATLAB. 6) And finally the performance analysis is carried out.

for generator:-

Type of modeling	implementation
Mapped Generator	This is also similar to mapped motor modeling where the input values for generator blocks are predefined or taken from the lookup tables here also simulation time is very less
Dynamic Generator	This model also represents an actual generator working in a real-time environment, where the output values calculated continuously according to change in input values as the equation is implementing .simulation time is more compared to the mapped generator

-To changed model type from mapped to dynamic or dynamic to mapped

-After entering into passenger block > electric plant> motor will get this window where MotGenMapped is by default selected as a model type for motor

-To change from MotGenEvMapped to MotGenEVdynamic

-first, we open our reference model into Matlab

here we are choosing EV as an example

then after clicking on the modeling section and after that in the design block, we will select the variant manager option

-after the variant manager window gets opened.

then by clicking on the passenger car expand option there will electric plant option that will expand that too in that will get both battery and motor

-we are taking motor as an example so after expanding the motor option we will get

1)MotGenEVdynamic

2)MotGenEVmapped

so the default one is MotGenmapped to change into MotGenEVdynamic

we need to right-click on our preference and after that, a pop up will be shown in which we need to select 'set as label mode active choice' and after that our motor variant will be MotGenEVdynamic

-same we can do for the battery to

- to verify whether its change or not will return to our model and open passenger block >electric plant>motor

and clicking on the motor block will get this window.

-as we can see we changed our variant from MotGenMapped to MotGendynamic

-a same procedure we can do for changing variant from MotGendynamic to MotGenMapped for both battery and motor.

that's how we can change our model type

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Q.1)How does the model calculate miles per gallon? Which factors are considered to model fuel flow?

Ans:-

Theory:-

MPG, or miles per gallon, is the distance, measured in miles, that a car can travel per gallon of fuel. MPG is also the primary measurement of a car's fuel efficiency: The higher a car's MPG, the more fuel-efficient it is.

The U.S. Environmental Protection Agency, or the EPA, is the government agency responsible for certifying a vehicle's MPG figures, notes How Stuff Works.

A car's MPG can be inconsistent because it is affected by a number of different factors, so it is difficult to get an accurate measurement. For example, factors like traffic and road conditions can affect MPG in any given context. That's why the EPA runs tests over a standard set of courses, then averages the results to calculate a vehicle's official MPG.

The EPA gives each vehicle three different MPG ratings, as All Car Leasing notes:

• Highway MPG: the average a car will get while driving on an open stretch of road without stopping or starting, typically at a higher speed.
• City MPG: the score a car will get on average in city conditions, with stopping and starting at lower speeds.
• And, combined MPG, a combined average of highway and city MPG.

In recent years, the EPA has expanded its testing capabilities to include alternatively-fuelled vehicles including electric vehicles. These ratings calculate the equivalent amount of energy that a vehicle uses to one gallon of traditional fuel. This allows consumers to compare the fuel efficiency of electric vehicles with regular ones.

MPG is an important metric to know about any vehicle that you're considering purchasing. It tells you about the difference in cost between operating different vehicles by giving you a sense of how much money you're likely to spend on fuel. This becomes especially important when fuel prices are higher, since every bit of savings count for your budget.

While MPG can help you compare different vehicles, it doesn't tell you anything about real-world fuel prices. However, you can easily calculate approximately how much you'll spend on fuel at different price levels, depending on how much distance you drive on a regular basis.

How does the model calculate miles per gallon?

-To calculate the fuel flow, vehicle speed & battery power are taken into consideration.

HEV model has separate blocks to calculate the MPG Which are shown below.

The above MPG calculation is for HEV which means it contains both fuel and battery energy.

-First, we get battery power in watt which is converted into kwatt and further converted into kw/h

-Then it's is converted into US gallon equivalent energy by dividing it by the standard value 33.7. Then converted into US gallons per second

-It is multiplied by standard value 0.00378541 to get volume in meter cube per gallon and it is added to the fuel flow for total value as it is an HEV

-Further meter Cube is converted into US gallon.

On the other hand, the speed of the vehicle is integrated to get distance and the distance which is in the meter is converted into mile by multiplying the standard value 0.000621371

FOR EV's

In the case of pure electric vehicle (EV) the term miles per gallon equivalent to (MPGe)

While the use of MPGe helps compare fuel efficiencies between vehicles, it has some limitations. The first limitation is that MPGe, like MPG, suffers from the "MPG illusion." So a better unit might be GGE per 100 miles or gasoline liter equivalents per 100 kilometers. The second limitation is that calculating the CO₂ emissions for an alternative fuel vehicle becomes difficult. The EPA only includes tailpipe emissions for vehicles. This is not much of a problem for gasoline or diesel fuel because of their energy density compared to production, transportation, and storage emissions. However, CO₂ emissions from the electricity needed to compress natural gas, keep liquid natural gas cold, or separate water to make hydrogen, or charge a battery are significant and are not included. Depending on the location and type of fuel, it is possible that using an alternative fuel vehicle will produce more CO₂ emissions or use more energy than a similarly sized gasoline or diesel-fueled vehicle

Here the value 33.7 kwh is the battery power required to get the energy equivalent to the energy which is obtained by consuming the 1 gallon of gasoline .it is calculated by the United States Environmental Protecting Agency(EPA).

There are sample stickers of HEV and EV provided by EPA:-

1) For HEV:-

For EV:-

Which factors are considered to model fuel flow?

-Vehicle speed

-Fule flow

-Battery power

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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.

steps that we carried out for this simulation

-first, we open a reference application for HEV from sources by Matlab help section.

This diagram shows the powertrain configuration.

after clicking on the HEV reference application file we directed to our Matlab window after reading the files inside that application we directed towards our Hev modeling section

-Double-clicking on the drive cycle block this window will pop up

-Inside this window, we can change our drive cycle from default to wide-open throttle and also can change

speed, time, acceleration, and simulation time.

in this window, we are going to enter our simulation stop time program execution type on accelerator mode and then hit run to simulate the results

-now we will put grade value and wind in the x-direction in the environmental block to see a difference in results.

and keeping all condition the same as above and running simulation one more time

we got these graph,

so we are going to write an observation about this graph

GRAPH 1:-Trace velocity vs Actual velocity

The yellow line indicates the trace velocity and the blue line indicates the actual velocity. by referring actual velocity line here we can see that vehicle requires from 2 sec to 20 sec time to achieve the maximum speed towards the targeted path by using battery power on. after that vehicle starts to deaccelerate.

GRAPH 2:- Engine motor Generator speed

As the battery is fully charged, at initial condition, only the motor speed (blue line indicate) is used which high at starting because of resistance due to slope and wind velocity. the engine speed (yellow line indication) is overlapped with generator speed(orange indication line)indicating both running on the same rpm. initial there is no need for the engine and generator speed as the motor is fulfilling the requirement to achieve the maximum speed of the vehicle. Therefore they are at 0 pm. but when the battery will discharging or when the state of charge(SOC)becomes below 70% then the only engine will start to rotate to provide and maintain the speed of the vehicle and so far generator will also start to charge the battery at the same time hence their rpm are the same.

GRAPH 3:- Engine torque, motor torque, and generator torque

As the battery is being used at the start, so torque will also maximum for the motor in this case until case until the vehicle acquires its maximum speed. once the vehicle reached at constant speed. the torque requirement will reduce. here also when there is deacceleration, the torque value becomes negative indicating no need of torque. Also it becomes constant once the battery goes into the charging state cause now. here engine torque is being used due below 70% SOC, Also,generator torque will be negative indicating that electric motor is charging and in this period engine has to overcome the torque requirement of vehicle successfully

GRAPH 4:- Battery current

when a vehicle uses an electric motor then only it is used to generate the power of the motor, when the vehicle accelerates, then no current is extracted to produce power for the motor. from the graph you also can see, the current requirement becomes stable when the battery charging mode is activated.

GRAPH 5:- SOC(state of charge)

state of charge(soc) is very important for battery-driven vehicles, from the graph it can be seen that the battery is used below 80%, the state of charges goes down and the battery goes on charging mode through generator once the the battery gets charged then its state of charge also increases and it won't fall down until battery is subjected to another operation

GRAPH 6:- MPGE

the graph show miles per gallon equivalent to run the vehicle during the higher speed the fuel need is high as the vehicle deaccelrate the the fuel requirement is less

these are the observation we studied from the graph

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

EV REFERENCE APPLICATION MODEL:-

-From given sources, we can open reference application for EV's

after clicking on that file we will be redirected to Matlab and after reading files inside that reference application Matlab will diverted us to the EV simulation model we are keeping all parameters the same as we applied for HEV

we will select the wide-open throttle cycle and make changes in the speed time and run time keeping all same as we used in the HEV model by clicking on the drive cycle block

and then putting environmental condition same as we used in HEV

-after that will run the cycle by keeping stop time as 40 sec and run in accelerator mode

-As the simulation gets over we will receive this graphs

from above the graphs:-

pure EV's can achieve less velocity than that of HEV's.HEV can achieve velocity upto 60kmph but in pure EV it is less than 60 mph.

motor speed in rpm is less than that of HEV, but the path tracing is the same

motor torque is almost the same as HEV

Battery current uses is half in EV to produce power as that of HEV

Also, battery use is less, battery draining is low and it can be seen in the graph of soc that keeping all the parameters the same

the battery uses is 5 times more in case of HEV than that of pure EV's.battery drains quickly in case of HEV

Fuel economy is almost double in the case of pure EVs than that of HEV's

RESULT:-

1)All the questions answered correctly are mention above

CONCLUSION:-

In this report, we have successfully studied HEV's and EV's simulation models and also tasted them for various condition, and also study their performance characteristics

REFERENCES:-

1) Reference application for HEV:-https://in.mathworks.com/help/autoblks/ug/explore-the-hybrid-electric-vehicle-multimode-reference-application.html

2) Reference application for PURE EV:-https://in.mathworks.com/help/autoblks/ug/explore-the-electric-vehicle-reference-application.html