Review of Early Work on Digital Displacement® Hydrostatic Transmission Systems

2018 ◽  
Author(s):  
Niall Caldwell
Keyword(s):  
Time Domain ◽  
Lumped Parameter Model ◽  
Primary Control ◽  
Hydrostatic Transmission ◽  
Load Sensing ◽  
Lumped Parameter ◽  
Good Comparison ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Work Done

The paper describes the work done by the author (1) from 1999 to 2006 to develop the Digital Displacement Pump (DDP) and Pump/Motor (DDPM) and demonstrate the feasibility of off-highway vehicle applications. The link between DDPM capacity and the solenoid valve performance was identified. Magnetic geometry was improved by parametric FEA, then time-domain behavior was improved with a hybrid FEA/lumped-parameter model. Software improvements allowed variable speed and bidirectional operation, enabling the demonstration of the first Digital Displacement Transmission (DDT) systems on a vehicle, one featuring a load-sensing DDP and secondary control by DDPM displacement, and one featuring primary control by DDP displacement and a conventional axial motor. A time-domain simulation was created of the primary-controlled vehicle, which yielded good comparison to experimental results. The deterministic nature of the DDP lends itself to model-based system design methods, which have since been used to develop larger commercial systems. The first detailed analysis of DDP efficiency characteristics revealed profound differences to conventional variable displacement pumps, including exceptional part-load efficiency and the dominant effect of fluid compressibility. A peak overall efficiency of 97% was recorded for a DDP after analysis of loss sources prompted design improvement.

scholarly journals Lumped parameter model and experimental tests on a pressure limiter for variable displacement pumps

2020 ◽  
Vol 197 ◽  
pp. 07005
Author(s):  
Paola Fresia ◽  
Massimo Rundo
Keyword(s):  
Experimental Tests ◽  
Control Flow ◽  
Lumped Parameter Model ◽  
Load Sensing ◽  
Axial Piston Pumps ◽  
Discharge Coefficients ◽  
Lumped Parameter ◽  
Variable Displacement ◽  
Flow Through ◽  
And Control

The paper presents the lumped parameter model of a pressure limiter for axial piston pumps developed in the Simcenter Amesim® environment. The control includes both the absolute and differential (load sensing) pressure limiter in a single body. The continuous position valve was tested experimentally alone on a test rig in order to estimate the discharge coefficients required for tuning the model. The tests were performed at imposed positions of the spool and the corresponding modulated pressure and control flow through the valve were measured. A contactless transducer was used for measuring with a very high accuracy the spool position. The influence of the bleed orifice on the pressure gain was also measured experimentally. It was found that the discharge coefficients have a significant influence on the hydraulic characteristic of the valve with also a consequence on the dynamic behavior of the entire displacement control.

Method for Lumped Parameter Simulation of Digital Displacement Pumps/Motors Based on CFD

2013 ◽  
Vol 397-400 ◽  
pp. 615-620 ◽  
Author(s):  
Daniel Beck Roemer ◽  
Per Johansen ◽  
Henrik C. Pedersen ◽  
Torben O. Andersen
Keyword(s):  
Computational Cost ◽  
Simulation Models ◽  
Lumped Parameter Model ◽  
Model Parameters ◽  
Lumped Parameter ◽  
Displacement Pump ◽  
Variable Displacement ◽  
And Performance ◽  
And Control ◽  
Low Computational Cost

Digital displacement fluid power pumps/motors offers improved efficiency and performance compared to traditional variable displacement pump/motors. These improvements are made possible by using efficient electronically controlled seat valves and careful design of the flow geometry. To optimize the design and control of digital displacement machines, there is a need for simulation models, preferably models with low computational cost. Therefore, a low computational cost generic lumped parameter model of digital displacement machine is presented, including a method for determining the needed model parameters based on steady CFD results, in order to take detailed geometry information into account. The response of the lumped parameter model is compared to a computational expensive transient CFD model for an example geometry.

scholarly journals The Hydraulic Power Generation and Transmission on Agricultural Tractors: feasible architectures to reduce dissipation and fuel consumption – Part 2

2020 ◽  
Vol 197 ◽  
pp. 07010
Author(s):  
Paolo Casoli ◽  
Barbara Zardin ◽  
Salvatore Ardizio ◽  
Massimo Borghi ◽  
Francesco Pintore ◽  
...  
Keyword(s):  
High Pressure ◽  
Fuel Consumption ◽  
Mechanical Energy ◽  
Pollutant Emissions ◽  
Medium Size ◽  
Load Sensing ◽  
Alternative Systems ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Agricultural Tractors

Increasing interest in reducing pollutant emissions and fuel consumption of off-road vehicles has led to research alternative systems that aim to reduce the power dissipations of the hydraulic circuits. This work presents the advantages of few alternative solutions for a hydraulic high-pressure circuit of a medium-size tractor. The standard high-pressure circuit is a typical multiusers load sensing system that uses a single variable displacement pump to feed: steering, trailer brake, rear remotes, hitch and suspension. The alternative architectures have been simulated and compared in terms of mechanical energy consumption. In particular, the steering has been separated from the circuit, it has been actuated by means of a dedicated pump moved by an electric motor, in this way the priority valve could be removed and losses due the pressure compensators are reduced. A further architecture based on the insertion of the LS signal conditioner was studied. The results show that relevant energy saving can be achieved with the new alternative architectures; the physical prototyping of the most promising solutions will be realized as the next step of the project.

Dynamic Analysis and Multi-Object Optimization of the Forced Torsional Vibration for Vehicular Multi-Stage Planetary Gears

2011 ◽  
Vol 86 ◽  
pp. 263-267 ◽  
Author(s):  
Hui Liu ◽  
Zhong Chang Cai ◽  
Chang Le Xiang ◽  
Ming Zheng Wang
Keyword(s):  
Steady State ◽  
Time Domain ◽  
Torsional Vibration ◽  
Vibration Response ◽  
Resonance Vibration ◽  
Lumped Parameter Model ◽  
Lagrange Method ◽  
Planetary Gears ◽  
Multi Stage ◽  
Lumped Parameter

On the basis of lumped parameter model and the Lagrange method, the model of powertrain was built. Resonance vibration response and non-resonance vibration response were calculated respectively in time domain and frequency domain, characteristics of forced torsional vibration in steady–state were concluded. Comparability and difference of response of parts in different stage were explained. Multi-object optimization was applied to reduce vibration.

Modeling and simulation of a hydrostatic transmission with variable-displacement pump

2000 ◽  
Vol 53 (4-6) ◽  
pp. 409-414 ◽  
Author(s):  
Andreas Kugi ◽  
Kurt Schlacher ◽  
Heinz Aitzetmüller ◽  
Gottfried Hirmann
Keyword(s):  
Modeling And Simulation ◽  
Hydrostatic Transmission ◽  
Displacement Pump ◽  
Variable Displacement

Computational Fluid Dynamic Modeling for Engine Diagnosis

2003 ◽  
Author(s):  
Girija Parthasarathy ◽  
Dinkar Mylaraswamy
Keyword(s):  
Fluid Dynamics ◽  
Numerical Models ◽  
Fluid Dynamic ◽  
Lumped Parameter Model ◽  
Heat Transfer Fluid ◽  
Dynamics Modeling ◽  
Computational Fluid Dynamics Modeling ◽  
Lumped Parameter ◽  
Computational Resources ◽  
Work Done

This paper presents the results of a demonstration problem where computational fluid dynamics modeling (CFD) is used for engine diagnosis. As computational resources become faster and cheaper and detailed numerical models of heat transfer, fluid dynamics and chemical kinetics become more accurate, these numerical models can become viable alternatives for seeded fault tests. The work done here is one of the ways this could be done; that is, by using the results of a CFD model to map the effects of certain faults to a model parameter computed by a less detailed lumped parameter model.

scholarly journals Experimental Validation of a Hydrostatic Transmission for Community Wind Turbines

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 376
Author(s):  
Biswaranjan Mohanty ◽  
Kim A. Stelson
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Pressure Control ◽  
Speed Ratio ◽  
Hydrostatic Transmission ◽  
Design Flexibility ◽  
Power Capture ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Hydrostatic Transmissions

Hydrostatic transmissions are commonly used in heavy-duty equipment for their design flexibility and superior power density. Compared to a conventional wind turbine transmission, a hydrostatic transmission (HST) is a lighter, more reliable, cheaper, continuously variable alternative for a wind turbine. In this paper, for the first time, a validated dynamical model and controlled experiment have been used to analyze the performance of a hydrostatic transmission with a fixed-displacement pump and a variable-displacement motor for community wind turbines. From the dynamics of the HST, a pressure control strategy is designed to maximize the power capture. A hardware-in-the-loop simulation is developed to experimentally validate the performance and efficiency of the HST drive train control in a 60 kW virtual wind turbine environment. The HST turbine is extensively evaluated under steady and time-varying wind on a state-of-the-art power regenerative hydrostatic dynamometer. The proposed controller tracks the optimal tip-speed ratio to maximize power capture.

Simulation Study on Load-Sensing Hydraulic Drawing System of Coal Mining Machine

2010 ◽  
Vol 37-38 ◽  
pp. 1195-1198
Author(s):  
Tian Hao Peng ◽  
Mei Sheng Yang ◽  
Xiao Song Hao ◽  
Jia Dong Liu
Keyword(s):  
Coal Mining ◽  
Simulation Study ◽  
Mining Machine ◽  
Plunger Pump ◽  
Load Sensing ◽  
Drawing System ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Working Principle ◽  
New System

A new hydraulic drawing system of coal mining machine is proposed in this paper. The variable plunger pump adopted in the hydraulic drawing system of coal mining machine is replaced by load-sensing variable displacement pump. The working principle and energy-saving of the new system are introduced. The performance of the new system is obtained by the simulation study using AMESim.

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