Project 2

The attachment has been downloaded from the given link.Next the downloaded file was taken in the current folder in MATLAB.

After this, Project2_InitFile.m was run and this resulted tranfer of data in MATLAB workspace.The data included altogether 93 parameters out of which 12 parameters are EM related,13 parameters are Eng related,15 parameters are ESS related and 53 are other parameters.

Conventional vehicle P1 model was copied and the same was modified as a hybrid vehicle model as per the guidance given in lectures/videos.The model begins with a 'Driver' block.This is essentially a PI Controller which generates acceleration and brake pedal outputs.This is done to match the actual and desired vehicle speeds.

The 'Controller' block is the brain of the vehicle and this represents the electronic control units.Based on the Driver inputs it generates desired engine torque, desired transmission gear and desired brake torque.

The above-mentioned inputs are fed to the 'Powertrain' block which represents the drive train of the vehicle.It consists of an Engine and an Electric Motor.The latter is connected to a Battery.The combined output of the Engine and the Electric Motor is fed to the 'Transmission Unit' via a Torque Converter. The output of the Transmission is fed to 'Wheels' which in turn drives 'Vehicle Dynamics'.'Wheels' provide the tractive force for the vehicle.The longitudinal dynamics of the vehicle along with the road load is represented in the 'Vehicle Dynamics' block.

The hybrid vehicle model so developed is attached as Proj2_VehicleModel.slx.

The above model contains 'To Workspace' blocks as per the requirement of Project2.The model was simulated and then plots obtained for both UDDS Drive Cycle and HWFET Drive Cycle.This was done by appropriate selection of Drive Cycle in Project2_InitFile.m.While Proj2UDFig#1A shows Motor Speed, Motor Torque and Input Power, Proj2UDFig#1B shows Voltage, Current & SOC,Proj2UDFig#1C shows map of Engine Fuel Consumption Proj2UDFig#1D shows Acceleration plus Brake, Transmission and Gear characteristics.All these correspond to the UDDS Drive Cycle. Likewise Proj2HWFig#1A,Proj2HWFig#1B, Proj2HWFig#1C & Proj2HWFig#1D show all similar parameters corresponding to the HWFET Drive Cycle.Pack Current,Terminal Voltage and SOC are also available in Scope Units for SOC ESTIMATION and TERMINAL VOLTAGE blocks in the model.

Fuel_Economy as obtained in the Workspace after running the simulation of the model is 2.8979 e+04 for UDDS Drive Cycle and 3.7059 e+04 for HWFEP Drive Cycle.The corresponding kmpl values are respectively 14.805 and 17.161.This indicates significant improvement in fuel economy for HWFET Drive Cycle.When compared with conventional vehicle model the improvement is even more for both the Drive Cycles.

[ The formula of kmpl is as under.

kmpl=Veh_Dist(end)/(Eng_Fuel_Consumption(end)/1000/

rho_petrol) ]

For UDDS Drive Cycle Veh_Dist(end)=12070 m

For HWFET Drive Cycle Veh_Dist(end)=16000 m

Also rho_petrol=0.7197

By running Convention Vehicle Model in Project 1 we find from the output display of SCOPE unit

Eng_Fuel_Consumption= 46.5 for UDDS Drive Cycle

and Eng_Fuel_Consumption= 26 for HWFET Drive Cycle

The comments on the plots is as under.

The torque requirements of the two Drive Cycles are different. HWFET Drive Cycle has higher power and torque requirement vis-a-vis UDDS Drive Cycle.It also has less negative torque & power requirement.

Acceleration and Brake pedals are used more because of lack of smoothness in the Drive Cycles and frequent gear shift requirement.Brake requirement is lower and mre use of Accelerator pedal is there in case of HWFER Drive Cycle.

Battery Pack Voltage remains around 156 Volts.Battery Pack Current shows a number of spikes for UDDS Cycle,but remains steady for HWFET Cycle.State of Charge(SoC) drops slowly from its initial value for UDDS Cycle and after initial decrease it marginally rises for HWFET Cycle.Battery Open Circuit Voltage marginally drops for UDDS Cycle and marginally rises for HWFET cycle.

Conclusion:

Forward Energy based model of a P1 Hybrid Vehicle has been developed using MATLAB and Simulink.The simulation run was carried out for both the specified Drive Cycles.Next the graphs /performance characteristics plotted using post processing script.Fuel Economy Number calculation was performed and thereafter comparison done between the specified Drive Cycles as well as with conventional vehicle model developed during Project 1.