Advanced Design and Optimal Sizing of Hydrostatic Transmission Systems

Guo, Xiaofan; Vacca, Andrea

doi:10.3390/act10090243

Cited by 8 publications

(4 citation statements)

References 22 publications

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“…The losses are related to unit fractional displacement β, pressure drop across the unit ∆p, and unit speed ω. A more detailed description on the setup of the hydraulic unit model can be found in [30].…”

Section: Test Rig Modelmentioning

confidence: 99%

A Variable Pressure Multi-Pressure Rail System Design for Agricultural Applications

2022

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This paper presents a solution for reducing energy loss in the hydraulic control system of agricultural tractors and their implements. The solution is referred to as a multi-pressure rail (MPR) and provides power to the hydraulic functions following a pressure control logic, as opposed to the traditional flow control logic typical of hydraulic systems used in off-road vehicles. The proposed hydraulic control system allows for elimination of redundant flow control valves in the state-of-the-art system, which cause excessive throttling losses leading to poor overall energy efficiency. Related work on MPR technology targets construction vehicles, where the MPR solution can allow energy recovery during overrunning loads and better engine management. This paper alternatively addresses the case of agricultural applications where functions mostly operate under resistive load conditions with slow dynamics, which offers an opportunity to target throttle losses. For this purpose, the paper introduces a variable pressure control strategy to handle the instantaneous pressure at each rail. To develop both the controller and the hydraulic system architecture, a stationary test rig is conceived and used to validate a numerical simulation model of the MPR system and its control strategy. Particular focus is given to the dynamic behavior of the system during the switches of a function between different pressure rails, which needs to ensure reduced oscillations of the flow provided to each hydraulic function. Once validated, the simulation model is used to predict the energy savings of the MPR solution in an actual application: a 435 hp hydraulic tractor powering a 16-row planter, for which operating features during typical drive cycles were available to the authors. The results show up to 59% total power reduction at the pump shaft, corresponding to 89.8% system efficiency gain.

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Section: Test Rig Modelmentioning

confidence: 99%

A Variable Pressure Multi-Pressure Rail System Design for Agricultural Applications

2022

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“…In single power flow transmission systems, the hydrostatic transmission system (HST), composed of a pump and a motor, is the only transmission system with both low-speed torque increase (the low-speed torque increase characteristic is a transmission characteristic that can ensure that the power source always rotates at high speed; the system speed ratio is inversely proportional to the torque ratio; and the maximum torque can be output at a zero speed ratio) and stepless speed regulation, except for automatic transmission. Some scholars have attempted to use HST to compensate for the shortcomings of the torque converter [5,6]. However, large-displacement pumps and motors are expensive, and the transmission efficiency of HST is extremely low under ultra-high-pressure operating conditions [7].…”

Section: Introductionmentioning

confidence: 99%

Configuration of the Power Reflux Hydro-Mechanical Transmission System

Wang,

Sun,

Wang

et al. 2024

Actuators

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The hydro-mechanical transmission system (HMTS) operates either in power split transmission mode (PSTM) or power reflux transmission mode (PRTM). Although PRTM is often ignored as a transition mode, this study reveals that the HMTS operating in the PRTM can accumulate the power input from the power source in the form of reflux power (in some references, scholars also refer to the reflux power as circulating power), thereby enabling the HMTS to exhibit a similar transmission performance as hydrodynamic transmission systems. Accordingly, this study applies the PRTM to the starting of construction vehicles and refers to the HMTS operating only in the PRTM as the power reflux hydro-mechanical transmission system (PHTS). By analyzing the internal relationship between the configuration and the power flow, transmission characteristics, energy storage mechanism, and energy loss mechanism of the PHTS, the optimal PHTS configuration suitable for construction vehicles was explored. The results indicate that reasonable configurations can enable the PHTS to significantly improve the efficiency of the construction vehicle transmission system, reducing energy consumption while ensuring power performance. Expanding the displacement ratio control range of the hydraulic speed regulation mechanism and combining the PRTM with the PSTM in an orderly manner can widen the high-efficiency range of the vehicle transmission system without increasing the number of vehicle gears.

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“…EHA is known for its exceptional attributes including high power density, reliability, and compactness. These characteristics have established EHAs as the preferred choice for modern aircraft [2], [3], and they are also finding increased utilization in various other industrial applications such as wind turbines [4], transport [5], [6], and exoskeleton robots [7], [8]. The elimination of a centralized hydraulic tank in an EHA can lead to heat accumulation within the system.…”

Section: Introductionmentioning

confidence: 99%

Thermal Characteristic and Analysis of Electro-Hydrostatic Actuator

Liu,

Huang,

et al. 2024

IEEE Access

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Electro-hydrostatic actuators (EHAs) are widely used due to their high integration and high power-to-weight ratio. However, the elimination of a centralized oil source in EHAs limits the cooling capacity of the system. Excessively high temperatures can have a significant impact on the performance and lifespan of the EHA. In this paper, firstly, the power loss during energy transfer and heat dissipation characteristics of EHAs are carefully examined. To further study the heat behavior, a one-dimensional simulation model of the EHA thermal-hydraulic system is developed. By comparing the simulation results with experimental data obtained from an actual EHA system, the good agreement between the simulation and experimental results confirms that the developed model can accurately simulate the thermal behavior of EHAs.Based on the validated model, the cooling scheme of EHAs is further explored. The cooling mechanisms of air cooling and phase change heat dissipation are considered to optimize heat dissipation and manage the temperature rise within the EHA. This research provides insights and guidance for the thermal design of EHAs in the early stages to ensure system performance and extend its lifetime.

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Advanced Design and Optimal Sizing of Hydrostatic Transmission Systems

Cited by 8 publications

References 22 publications

A Variable Pressure Multi-Pressure Rail System Design for Agricultural Applications

A Variable Pressure Multi-Pressure Rail System Design for Agricultural Applications

Configuration of the Power Reflux Hydro-Mechanical Transmission System

Thermal Characteristic and Analysis of Electro-Hydrostatic Actuator

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