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?

ans:-

• In powertrain blockset provides two types of combustion models
• mapped and dynamic model.
• When you customize a SI or CI reference application, you can use either a dynamic or mapped engine.
  
  

Mapped model :-

IMPLEMANTATION:-

• 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. in this model data is taken from lookup table charaactrises engine/ motor/ genrearator under certain parameters.
• this model repesents macro engine behaviour as set of lookup table(brake torque,fuel flow,air mass flow, exhaust temperature,efficiency and emissions) as a function of commanded load

WHEN TO USE:-

• If you have engine data from a dynamometer or a design tool like GT-POWER.
• For quasi steady-state engine simulations.

DYNAMIC MODEL

IMPLEMANTATION:-

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.

WHEN TO USE:-

• 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

HOW CAN CHANGE THE MODEL TYPE :-

following steps for changing the model

• open the model click on passenger_car/electric_plant/motor/
• right click select varient/label_mode_active_choice/motgenevedynamic

1) click on passenger car

2) select electric_plant

3) select motor

4) right click select varient/label_mode_active_choice/motgenevedynamic

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

MPG is a fuel economy rating determined by how far a car can travel on a gallon of gasoline or diesel

with the calculation of MPG efficiency of a vehicle is determined

MODEL CALCULATION OF MPG :-

• The model calculate the MPG& L/100, by considering vehicle speed , fuel volume flow and battery power as a input
• the input for the US MPG calculation are vehicle speed in miles & fuel flow volume in gallons.

FACTORS THAT AFFECT THE FUEL ECONOMY:-

• Excessive short trips
• heavy braking & acceleration
• frequent cold weather travel
• high vwhicle weight or towing weight
• speeding
• hill climbing
• bad road

Q3- Run the HEV ReferenceApplication with WOT drive cycle. Change the grade and wind velocity in the environment block. Comment on the results

ANS:-

HEV REFERANCE APPLICATION WITH WIDE OPEN THROTTLE DRIVE CYCLE

• vehicle is idle for 0-5 sec. and the input speed is 50 mph
• vehicle will start deccelerating after 80secs.
• final speed is 0 mph which will take 5 secs after decceleration start
• model & simulation time is 210 secs

RESULTS:-

TRACE VELOCITY:-

• time required for maximum velocity of 50mph is 46.53 secs
• after achieving required input velocity, velocity is constant till decceleration (80)
• after that vehicle speed is 0 mph from 85 secs to 210

battery current :-

• consumption of current is high while achieving max velocity
• consumption of current decreased while constant velocity.
• current value goes negative after deceleration

battery SOC:-

• soc is started decreasing till deceleration of 80 secs.
• at the time of decceleration and braking motor is act as a generator.

• KEEPING OTHER ALL PARAMETERS SAME AND JUST CHANGING WIND VELOCITY AND GRADE FROM THE ENVIRONMENT

• some values are changed in the environment
• grade is 5 and velocity is 10
• and remaining all parameters are same

• with this changes in environment required time to achieve maximum speed is greater than no changes in the environment
• this is only the major effect on the result:
• this issue can be overcome by increasing battery current and the engine power.

Q4:-Keeping all other parameters same, compare the simulated results of hybrid and pure electric powertrains.

ANS:-

case1:- HEV multimode reference application.

• open the HEV multimode reference application mode in MATLAB.
• The model consist of enviroment block, car passenger block, longitudinal driver and visulization subsystem.
• open the enviroment block and change the grade value to 5 and wind velocity to 10.
• now run the simulation with 2474 seconds and go to the visulization block to see the graph.

model:-

Result graph:-

case2:- pure electric vehicle reference application.

• open the pure electric vehicle reference application mode in MATLAB.
• The model consist of enviroment block, car passenger block, longitudinal driver and visulization subsystem.
• open the enviroment block and change the grade value to 5 and wind velocity to 10.
• now run the simulation with 2474 seconds and go to the visulization block to see the graph.

Model:-

RESULT GRAPH:-

Conclusion:-

• battery current is continuosely changing in HEV due to charging and discharging while in pure EV the battery current is continuesly dropping.
• the US fuel economy is high in pure EV compared to HEV, travelling cost is less for EV.
• The motor speed(RPM) is high for HEV compared to EV.