DRIVER MODEL ANALYSIS USING CUSTOMISED DRIVE CYCLE AND PERFORMING WOT ANALYSIS ON GMEV1 CAR.

DRIVER MODEL ANALYSIS USING CUSTOMISED DRIVE CYCLE AND PERFORMING WOT ANALYSIS ON GMEV1 CAR

OBJECTIVE:

• To find the ratio of hill-climbing power required by fully loaded tata ultra truck to the half-loaded one.
• To find how much can be the minimum length of the flyover, considering the minimum height at the summit should be 5.5 meters.
• To prepare a new drive cycle excel file representing hill climbing angle corresponding to speed and time.Revise the model file "driver_glider.slx" such that it can calculate gradient force from drive cycle.
• Model the WOT (wide open throttle ) of GM EV1 car.Compare it with the official figures of the performance of a real vehicle. prepare a table showing variation in acceleration time with 5% change in vehicles parameters.

STUDY_1:

• Ratio of hill climbing power required by fully loaded TATA truck to the half loaded one.

VEHICLE AT FULL LOAD

Gross vehicle weight= kerb weight +payload

=3735+8255

=11990kg

Gradeability=25.6% Therefore angle = 15 degrees

Hill climbing force=mass *gravity*sin(`theta`)

=11990*9.81*sin(15)

=76448.1N

Considering velocity of the vehicle= 25 kmph or 7 m862.5/s

Calculating the hill climbing power = hill climbing force * velocity of the vehicle

=76448.1*7

power at full load=535136.7W

VEHICLE AT HALF LOAD

Gross vehicle weight= kerb weight +payload/2

=3735+8255/2

=7862.5 kg

Hill climbing force= mass*gravity*sin(`theta`)

=7862.5*9.81 *sin(15)

=50157.45N

Considering velocity of the vehicle = 7m/s

Hill climbing power= hill climbing force *velocity of the vehicle

=50157.45*7

power at half load =351102W

Ratio of powers= power at full load /power at half load

535136.7/50157.45 = 1.524

STUDY_2:

MINIMUM LENGTH OF FLYOVER, SUMMIT MINIMUM HEIGHT 5.5M

Given, rise =5.5m

angle=15 degrees

since it is a right angle triangle

sin(theta)=5.5/ length

sin(15) =5.5/length

minimum length of flyover= 21.25meters

Applying pythagoras theorem

=length^2=rise^2+run^2

minimum run of flyover = 20.5meters

STUDY-3:

Prepare a new drive cycle excel file for the model and also include a hill climbing angle to it.

Input for driver_glider.slx file is made in excel.

Giving this drive cycle as input for the existing driver_glider.slx model. we need to import this excel data to MATLAB workspace by using import data option .so this file is imported by using the name "velocity",

and is shown in workspace in matlab'.

The instructions given in help section article was followed.After importing and replacing the new drive cycle through workspace , the simulink model looks ike this:

MODEL:

DRIVE CYCLE GOOGLE SHEET LINK AS INPUT:https://drive.google.com/file/d/13VyTrmMwR5k0TPbeUjlv7lTd8imMjPv0/view?usp=sharing

OUTPUT:

STUDY_3:

Modelling the WOT (Wide Open Throttle) response of GM EV1 car and Comparing it with the official figures of the performance of a real vehicle. Prepare a table showing variation in acceleration time with a 5% change in vehicle parameters.

Theory:

Wide open throttle(WOT) refers to an engine maximum intake of air and fuel that occurs when the throttle plates inside the carbuerettoror throttle body are "wide open".Providing the least resistance to the incoming air. In the case of an automobile. WOT is when the accelerator is depressed fully. In the case of a diesel engine which does not have a throttle value ,WOT is the point t whivh the maximum amount of fuel is being injected relative to the amount pumped by the engine, generally in order to bring the fuel-air mixture upto the stoichiometric point.

Given GMEV1 data:

Mass of vehicle=1540kg

Drag coefficient Cd =0.19

Angular velocity=733rad/sec

coefficient(rolling resistance)=0.0048

Gear ratio=11

Efficiency of drive =0.95

Tyre radius=0.3m

Critical velocity= 19.8 m/s

Motor torque =140 nm

Motor speed=12000rpm

Constant power=102kW

Maximum velocity=35.8m/s

CASE 1= PARAMETERS OF GMEV1 VALUES:

A] Below critical velocity (19.8m/s) we use this below equation: Here torque is constant but power varies .

`dv=dT.(3.07901-0.00013698.v^2)`

B] Between critical velocity (19.8m/s) and cutoff velocity (35.8m/s). we use this below equation:

`dv=dT*((61.5227/v)-0.04648-(0.00013698*v^2))`

CASE 2= PARAMETERS OF GMEV1 VALUES WITH 5% INCREASE:

A] Below critical speed velocity (19.8m/s) we use this below equation: Here torque is constant but power varies.

`dv=dT*(2.92839-0.00013698*v^2)`

B] between critical velocity(19.8m/s) and cutoff velocity (35.8m/s). we use this below equation:

`dv=dT*((58.6083/v)-0.04880-(0.00013689*v^2))`

IMPLEMENTING FORMULAS IN EXCEL TO FIND OUT ACCELERATION TIME FOR GMEV1 VALUES AND FOR GMEV1 VALES WITH 5% INCREASE :

FORMULAS IN VEHICLE COLOUMN

Below critical speed-

Between critical velocity and cutoff velocity-

google sheet link :https://docs.google.com/spreadsheets/d/1D_U9m4YFY1JwsOlLZdjByk16XEYt9ggSvK9-9Iw7YFc/edit?usp=sharing

Similarly, this process is repeated with 5% change in vehicle parameters. and it is clearly evident from the data in excel sheet that the velocity of the vehicle remains constant after it reaches its maximum value thus we conclude that vehicle 1 reaches its top speed in 24 seconds whereas vehicle 2 with 5% increse in parametrs reaches its top speed in 15 secs.

CONCLUSION:

Thus we have successfully completed all the questions with proper output and matlab code .

Study1- Ratio of powers=1.524

Study2- Minimum length of flyover=20.5meters

Study3- Graphical representation

Study4- Googlesheet link.