Optimization of Complex Hydromechanical

Transmissions

Karl Pettersson

Fluid and Mechatronic Systems (Flumes)

Department of Management and Engineering

Linköping University

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Requirements

Steplessly variable torque/speed ratio in a wide range

Kept traction force during gear shifts

High efficiency throughout the speed range

Decoupling of the engine speed from the output speed

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Mechanical Power

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Power-split

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Backwards Calculations

η = 99%

Load

1800 rpm η = 95%

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Mode shift

Full mechanical power transfer

Optimize the energy efficiency by positioning the mode shifts!

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Short Loading Cycle

Load-Carry Cycle

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karl.pettersson@liu.se