presenters: mr. moresh kolhe mr. babu bhondave …...mahindra & mahindra herein referred to as...
TRANSCRIPT
1Copyright © 2012 Mahindra & Mahindra Ltd. All rights reserved. 1
Presenters:
Mr. Moresh KolheMr. Babu Bhondave
Mahindra & Mahindra (AFS)
2Copyright © 2012 Mahindra & Mahindra Ltd. All rights reserved.
Overview of Presentation
• Introduction.
• Objective.
• PST valve model using Simulink-Simscape.
• Results and Summary
• Summary
3Copyright © 2012 Mahindra & Mahindra Ltd. All rights reserved.
Introduction
• Power shuttle transmission generally used in Tractors, consists of multi-plate (wet) clutch and an additional hydraulic unit i.e. power shuttlevalve.
• The Forward/Reverse operation with Power shuttle transmissionprovides better comfort, controllability and improves productivityespecially in Loader-Dozer application..
• The power shuttle valve is operated by a F/R lever. In forward position,the pressure is built in the forward clutch whereas in reverse position,the pressure is built in the reverse clutch.
• This pressure rise in the F/R clutch makes the vehicle to make in F/Rdirection. Flow to tank line is blocked during the flow to F/R clutch.
4Copyright © 2012 Mahindra & Mahindra Ltd. All rights reserved.
Objective
• To study the pressure modulation and effect of variousparameters on pressure modulation of the Power shuttlevalve.
• To optimize the pressure modulation curve for shifting jerksand delay.
• To reduce the no of trials to be done on actual vehicle forthe purpose of optimization.
5Copyright © 2012 Mahindra & Mahindra Ltd. All rights reserved.
Power Shuttle Transmission
PST Valve
Forward Clutch engaged and
Reverse Clutch disengaged
F/R Lever
Reverse Clutch engaged and
Forward Clutch disengaged
PST Valve
Pedal pressed, Clutch disengaged
Inching Pedal
Pedal released, Clutch Engaged
6Copyright © 2012 Mahindra & Mahindra Ltd. All rights reserved.
PST Valve Model
• Power shuttle valve components like priority section, modulationsection, inching section etc. are modelled.
• Operator input operates the F/R and inching control.
• Mathematical model for Spring and Constraints is developed in Simulinkand for other components Simscape is used.
• Priority valve ensures a fairly constant flow rate from Pump to the F/Rvalve which also flows to modulation valve.
• F/R valve is connected to the Clutch which is engaged by the fluidpressure.
• Inching valve relieves the pressure in the clutch thereby allows inchingof the vehicle.
7Copyright © 2012 Mahindra & Mahindra Ltd. All rights reserved.
PST Valve Model
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Results
Pressure v/s Time for F/R operation.
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Results
Pressure v/s Time for Inching operation.
10Copyright © 2012 Mahindra & Mahindra Ltd. All rights reserved.
Conclusion
• A optimized solution for this PST is obtained, which is very close to theactual requirement.
• Using this simulation for determining modulation curve, physical testneeded for PST optimization reduced significantly.
• The results obtained from this kind of simulation provides not only basisfor evaluation of PST valve performance but also for enhancement thatcan be done in the design.
• Other issues, if simulated and verified, they can be resolved at an earlystage.
• Risk of introducing new concepts can be reduced with these kind ofvirtual validation
11Copyright © 2012 Mahindra & Mahindra Ltd. All rights reserved.
References
• H. Merrit, Hydraulic Control Systems, JohnWiley & Sons, INC, 1967.
• John S. Cundiff, Fluid Power Circuits and Controls (Fundamentals andApplications), CRC Press, 2001.
• Matlab-Simulink-Simscape users guide.
• Matlab-Simulink-Simscape Tutorials.
12
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Copyright © 2012 Mahindra & Mahindra Ltd. All rights reserved.
Thank you
Visit us at www.mahindra.com
Acknowledgement
I wish to express my warm thanks to Mahindra management for providing the opportunity to
work on this project. Also I would like to express my sincere gratitude to Knowledge Management
team for their support.