Week-11 Challenge: Braking
- For a defined driving cycle, calculate the energy required for braking
Ans:BE=1/2mv^2
BE = braking energy
m = mass of the vehicle
v = velocity
By this above formula me can calculate the how much energy will be required by the vehicle for breaking at different velocity.
In this manner the same calculation is been carried out for calculating the brake efficiency that would be required at the peak point.
here the mass of the vehicle is 1100.
The above reults shows how the velocity the driving cycle and required breaking energy.
The drive cycle are the given points at which different velocity at different time are given .
The orange line is the velocity and gray line is the energy required for breaking.
2.Why electric motor can’t develop braking torque at high speed similar to starting? How electric and mechanical brakes are coordinated?
Ans:-
i)From above torque speed charachteristics we can understant that initial the value of torue is higha nd maintain constat but after the speed gets incresed the value of torque goes on decreasing.
ii)so, we can say the torque and speed are inversely prpoprtional as when torque is high speed is low and when speed is high the torque is low.
iii)In the low speed operation of the motor,the motor can deliver high torque which can used for breaking.
iv)When vehicle speeds up the motor is no longer in the state of delivering high torque which will be required for breaking the vehicle.
v) therfore breaking is done with the help of mechnical breakes in such case.
Two methods of breaking:
Series: In this type of breaking firstly electrical braking is done then the mechinical brakers are used to stop the vehicle.
Parallel:In parallel braking both the electrical as well as mechnical breaking are used together to stop the vehicle.
This the breaking method adopted by then nissan lead .EDIB (ELECTRONIC DRIVEN INTELLEGENT BRAKING)
In the above diagram Both the brakes are used:-
i)When the Speed of the motor is low the major braking is down by electrical brakes and some aditional breaking is only done with the help of mechnical breakes.
ii)When the vehicle is running at high speed then the major work is done with the help od mechincal brakes and limited amount of breaking is electrical.
3.Make a MATLAB program which plots contour of given motor speed, torque and efficiency values. Attach the code as a .m file attach a screenshot of all the plots.
Ans:-The colorbar shows the efficiency areas.
