A Novel Pump-Decoupled Hydrostatic transmission Architecture to Reduce Energy Consumption of Agricultural Harvesters
Hydrostatic transmission (HT) systems are among the most efficient hydraulic architectures for rotary actuation due to their ability to avoid energy losses from throttling. They also facilitate seamless power transfer under high loads through a continuously variable transmission (CVT) ratio. Furthermore, series HT configurations with fixed displacement secondary units can drive multiple speed-synchronized functions using a single pump, offering cost-effective and efficient operation. As a result, agricultural harvesters depend on series HT systems to power their numerous speed-synchronized rotary functions, which must handle high peak loads and fluctuating power demands. However, despite having throttle-less operation, the overall efficiency of HT systems in general is often low because the primary and secondary units frequently operate outside conditions that enable optimal efficiency. This leads to lower fuel efficiency and higher emissions in harvesters. Therefore, improving the efficiency of HT systems remains a key focus of research in the fluid power community, both in academia and industry.
This study introduces a novel hydrostatic transmission architecture that enhances transmission efficiency, compatible with multiple motors in series and adaptable for use across various subsystems within a single machine, thus making it suitable to be implemented for harvester applications. The architecture decouples the operating conditions of the primary unit from those of the HT, allowing the primary unit to operate at more efficient operating points, particularly by optimizing its fractional displacement. Additionally, it preserves the energy efficiency of the secondary unit, resulting in a significant overall improvement in HT efficiency.
To evaluate the energy efficiency benefits, the basecutter system of a sugarcane harvester is used as a reference case. Lumped-parameter models for both the baseline commercial system and the proposed architecture are developed. Simulation results for a realistic drive cycle demonstrate a 10–20% reduction in energy consumption for the proposed system variants compared to the baseline HT system, validating the effectiveness of the proposed approach.
History
Degree Type
- Master of Science in Mechanical Engineering
Department
- Mechanical Engineering
Campus location
- West Lafayette