Vehicle at rest requires no load for obvious reasons, but when the vehicle starts moving it has to overcome Mass of the vehicle, slip between road surface and tire so the torque required is huge if I am right. But as the vehicle starts to move and picks up speed the torque load acting now should vary. So my question is how do I determine this varying torque load experienced by the motor?
In normal use, the torque at the wheels is determined by the required acceleration, tire friction, wind+aerodynamic and slope. There is also a possibility to make bearing loss and gear loss model. The speed of the motor depends on the gear ratios, tire diameter and the slip of the tires, which is usually between +2%/-2% in normal torques.
The discussion about tire friction effect of wind, even radiator effect can be found in my articles. If you look at this presentation and the references after the "thank you", it can help you.
https://www.researchgate.net/publication/281584740_How_to_reduce_the_energy_needs_of_electrical_and_conventional_vehicles
Often temperature and pressure of tires is not considered, also wind conditions, but they influence the range.
Spur gears have an efficiency of 98%/stage at full load, but the no load loss should be measured separately, it depends mainly on the oil viscosity.
The driving cycles NEDC WLTC do not consider hills, no sustained low speed below 15km/h. The NEDC has very slow accelerations of 0.5m/s^2, finally it is not realistic for the estimation of the range, nor the required torque or power.
This might interest you as well: hybrid tuktuk https://youtu.be/JlXImvPIk-Q
Alex
Conference Paper How to reduce the energy needs of electrical and conventional vehicles
Hi,
If I understand you well you are interested in practical solution. If you need a theory, there are many books related to vehicle dynamics. Coming back to practice.
You can choose at least one of three methods:
1. You can measure in elctric way power consumtion and rpms. From these values you can get the torque.
2. You can apply torque meter between electric motor and transmisson.
https://www.hbm.com/en/0264/torque-transducers-torque-sensors-torque-meters/
3. You can use electric motor with flexible mounting, equipped with reaction arm pushing on the force sensor. Knowing the arm lenght and the force you have got the torque.
With regards,
Jerzy
Dear Santosh,
Regarding your main question, you may have look on our paper were the vehicle dynamics have been taken into account.
Regards,
Mohamed
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