Novel Hydraulic System for Mini Excavators Without Electronic Controls

2016 ◽  
Author(s):  
Ken Sugimura ◽  
Hubertus Murrenhoff
Keyword(s):  
Urban Areas ◽  
Hydraulic System ◽  
Mechanical Valve ◽  
The Novel ◽  
Hydraulic Systems ◽  
Pressure System ◽  
System Architectures ◽  
Load Sensing ◽  
Controlled Systems ◽  
Hydraulic Excavators

The target application of this study is hydraulic excavators, which are one of the most common machines found at construction sites across the world. Road constructions and improvements, laying operation of cables or pipes and building can be seen in urban areas and digging and dumping operations of natural resource are done in country regions. For the construction site in urban areas, mini hydraulic excavators with operating weights up to 6 tons are often used and they make up more than 60% of the total hydraulic excavators market [1]. In recent years, a number of new system architectures for mobile hydraulic systems have been proposed. Examples of such improved architectures are displacement control, transformer systems and valve controlled systems with multiple pressure rails. For these systems, electronic controls are always used. Although these new methods are promising, they cannot be applied to mini-excavators, because today’s mini-hydraulic excavators do not use electronic controls as this would increase costs and make the system complex. Therefore, the goal of this study is to propose a fully hydro-mechanical valve controlled constant pressure system, which can be applied to mini-excavators in the future. This paper begins by introducing the details of this novel hydraulic system and shows its advantages. Using a simulation model of an 18 ton excavator, it is confirmed that the novel system functions well and the energy efficiency is compared to a conventional Load Sensing system. The simulation results show that the novel system can save 22% and 24% of fuel in leveling and 90° dig-dump cycles respectively.

Soft Switching Approach to Reducing Transition Losses in an On/Off Hydraulic Valve

2009 ◽  
Author(s):  
Michael B. Rannow ◽  
Perry Y. Li
Keyword(s):  
Hydraulic System ◽  
Check Valve ◽  
Fluid Flows ◽  
Soft Switching ◽  
Total System ◽  
System Efficiency ◽  
Hydraulic Systems ◽  
Controlled Systems ◽  
Flow Through ◽  
Hydraulic Valve

A method for significantly reducing the losses associated with an on/off controlled hydraulic system is proposed. There has been a growing interest in the use of on/off valves to control hydraulic systems as a means of improving system efficiency. While on/off valves are efficient when they are fully open or fully closed, a significant amount of energy can be lost in throttling as the valve transitions between the two states. A soft switching approach is proposed as a method of eliminating the majority of these transition losses. The operating principle of soft switching is that fluid can temporarily flow through a check valve or into a small chamber while valve orifices are partially closed. The fluid can then flow out of the chamber once the valve has fully transitioned. Thus, fluid flows through the valve only when it is in its most efficient fully open state. A model of the system is derived and simulated, with results indicating that the soft switching approach can reduce transition and compressibility losses by 79%, and total system losses by 66%. Design equations are also derived. The soft switching approach has the potential to improve the efficiency of on/off controlled systems and is particularly important as switching frequencies are increased. The soft switching approach will also facilitate the use of slower on/off valves for effective on/off control; in simulation, a valve with soft switching matched the efficiency an on/off valve that was 5 times faster.

STEAM: A Mobile Hydraulic System With Engine Integration

2013 ◽  
Author(s):  
Milos Vukovic ◽  
Sebastian Sgro ◽  
Hubertus Murrenhoff
Keyword(s):  
Hydraulic System ◽  
High Efficiency ◽  
Combustion Engine ◽  
Low Cost ◽  
Total System ◽  
Hydraulic Systems ◽  
Pressure System ◽  
Operating Modes ◽  
Hydraulic Design ◽  
Displacement Pump

In recent years, research institutions worldwide have developed a number of new mobile hydraulic systems. Despite their improved energy efficiency, these systems have yet to gain market acceptance due to their related increase in component costs and decrease in robustness. At the Institute for Fluid Power Drives and Controls in Aachen, a new system for mobile machines, named STEAM (Steigerung der Energieeffizienz in der Arbeitshydraulik mobiler Arbeitsmaschinen), is being developed using inexpensive off-the-shelf components. The aim is to improve the total system efficiency by considering all the subsystems in the machine. This is done by integrating the internal combustion engine (ICE) into the hydraulic design process. By using a constant pressure system in combination with a low-cost fixed displacement pump the hydraulic system is designed to ensure the ICE experiences a constantly high load in a region of high efficiency, so-called point operation. To decrease the hydraulic losses incurred when supplying the linear actuators with flow, an additional intermediate pressure rail with independent metering edges is used. This enables various energy efficient discrete operating modes, including energy regeneration and recuperation.

Soft Switching Approach to Reducing Transition Losses in an On/Off Hydraulic Valve

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Michael B. Rannow ◽  
Perry Y. Li
Keyword(s):  
Hydraulic System ◽  
Check Valve ◽  
Fluid Flows ◽  
Soft Switching ◽  
Total System ◽  
System Efficiency ◽  
Hydraulic Systems ◽  
Controlled Systems ◽  
Flow Through ◽  
Hydraulic Valve

A method for significantly reducing the losses associated with an on/off controlled hydraulic system is proposed. There has been a growing interest in the use of on/off valves to control hydraulic systems as a means of improving system efficiency. While on/off valves are efficient when they are fully open or fully closed, a significant amount of energy can be lost in throttling as the valve transitions between the two states when the switching times are not negligible. A soft switching approach is proposed as a method of eliminating the majority of these transition losses. The operating principle of soft switching is that fluid can temporarily flow through a check valve or into a small chamber while valve orifices are partially closed. The fluid can then flow out of the chamber once the valve has fully transitioned. Thus, fluid flows through the valve only when it is in its most efficient fully open state. A model of the system is derived and simulated, with results indicating that the soft switching approach can reduce transition and compressibility losses by 81% and total system losses by 64%. The soft switching approach has the potential to improve the efficiency of on/off controlled systems and is particularly beneficial as switching frequencies are increased. The soft switching approach will also facilitate the use of slower on/off valves for effective on/off control; in simulation, a valve with soft switching matched the efficiency of an on/off valve that was 4.4 times faster.

A New Approach to Sizing Low Pressure Systems

2017 ◽  
Author(s):  
Nathan Keller ◽  
Monika Ivantysynova
Keyword(s):  
Hydraulic System ◽  
Low Pressure ◽  
Hydraulic Systems ◽  
Pressure System ◽  
Hydraulic Unit ◽  
Duty Cycles ◽  
Low Pressure System ◽  
Hydrostatic Transmissions ◽  
Cylinder Flow ◽  
Low Pressure Systems

Closed-circuit hydraulic systems, like hydrostatic transmissions and Displacement Controlled (DC) architecture systems, require an integrated low-pressure system. These low-pressure systems provide several important functions to the hydraulic system. They prevent cavitation, provide cooling flow through the cooler, replenish the hydraulic system with cool oil, assist in the oil filtration process, provide pressure to the hydraulic unit control systems and, in the case of DC systems with differential cylinders, balance the unequal cylinder flow. Traditionally, the sizing of low-pressure systems is accomplished using a static sizing approach. In this approach, a constant efficiency of the hydraulic units is assumed, and the system is operating at a maximum power condition. The result is often an oversized charge pump and accumulator, if one is present. A dynamic sizing method has been developed using MATLAB/Simulink® with high fidelity empirical loss models for hydraulic displacement machines. Using realistic duty cycles for hydraulic systems and measured data, the low-pressure system can be accurately sized. Dynamically sizing low-pressure systems reduce parasitic losses on the prime mover because of smaller pump sizes, thus freeing power to be used elsewhere. Another concept presented in this work is the possibility of isolating the hydraulic unit control pressure supply and the low-pressure system. Realistic examples have been simulated to demonstrate the power savings of dynamically sizing low-pressure systems.

Energy Efficient Excavator Hydraulic Systems With Digital Displacement® Pump-Motors and Digital Flow Distribution

2020 ◽  
Author(s):  
Jill Macpherson ◽  
Christopher Williamson ◽  
Matthew Green ◽  
Niall Caldwell
Keyword(s):  
Power Distribution ◽  
Hydraulic System ◽  
Energy Recovery ◽  
Flow Distribution ◽  
Small Scale ◽  
Hydraulic Systems ◽  
System Architectures ◽  
Fuel Savings ◽  
Duty Cycles ◽  
Displacement Pump

Abstract Environmental and economic factors are driving the development of more fuel efficient off-highway vehicles. The pathway to fuel savings of greater than 50% in an excavator application through utilisation of system architectures unlocked by Digital Displacement technology is presented. Pump flow distribution using digital valves instead of traditional proportional control valves is demonstrated experimentally. The “Workbus” power distribution scheme is demonstrated on a small scale backhoe arm on a laboratory test rig. These tests do not include hydraulic energy recovery. A backward-facing simulation of an 18 tonne excavator is described. The simulation uses input data collected from grading and lorry loading duty cycles. Applying the workbus system architecture to the excavator in simulation, fuel savings of 31% to 48% are realized. With the addition of energy recovery capability via Digital Displacement Pump-Motors, simulated fuel savings are 53% to 58% compared to the original excavator hydraulic system.

scholarly journals An Energy Efficient Two-Stage Supply Pressure Hydraulic System for the Downhole Traction Robot

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Delei Fang ◽  
Jianzhong Shang ◽  
Junhong Yang ◽  
Zhuo Wang ◽  
Yong Xue ◽  
...  
Keyword(s):  
Energy Loss ◽  
Mobile Robot ◽  
Energy Efficient ◽  
Hydraulic System ◽  
Hydraulic Drive ◽  
The Novel ◽  
Pressure Source ◽  
Two Stage ◽  
Pressure System ◽  
Supply Pressure

The efficiency of hydraulic drive system has become one of the significant issues in mobile robot. In this paper, an energy efficient two-stage supply pressure hydraulic system is proposed to solve the energy waste in the one-stage supply pressure system of the downhole traction robot. This novel two-stage hydraulic system can match different pressure requirements of actuator by changing the modes of supply pressure, which is helpful to reduce the energy loss and improve the efficiency for traction robot. Based on the robot working principle, the load characteristics in different actuators are obtained and the shortage in traditional hydraulic system is analyzed. The novel hydraulic system which consists of a high-pressure source and a low-pressure source is designed, including the system structure and energy supply method. According to the energy flow process, energy loss models of the system and components are established to analyze energy-saving principle of the novel hydraulic system. The feasibility and efficiency of two-stage supply pressure system are verified by simulating the operating process of telescopic mechanism. Finally, the simulation shows that control precision of the novel system can reach 3.5 mm and the efficiency is increased to 59.53%, which can provide theoretical reference for design of hydraulic drive system in traction robot and the efficiency improvement of multiactuator mobile robot.

The Modeling Analysis and Dynamics Simulation of Load-Sensing Hydraulic Systems

2011 ◽  
Vol 317-319 ◽  
pp. 307-313 ◽  
Author(s):  
Cong Mei Wei ◽  
Jin Yi Lian ◽  
Jing Jie Li
Keyword(s):  
Simulation Model ◽  
Hydraulic System ◽  
Simulation Analysis ◽  
Dynamics Simulation ◽  
Hydraulic Systems ◽  
Load Sensing ◽  
Modeling Analysis ◽  
Analysis System ◽  
Working Device ◽  
The Mathematical Model

This paper analyzes the mathematical model of load-sensing hydraulic system based on power linkage graph method and builds the simulation model AMESim of the system. The load sensitive hydraulic system is applied in the working device of loader, and the simulation model AMESim with ADAMS is built by combining the dynamics analysis system with ADAMS,. The study of simulation on the dynamics is completed under different working conditions and the results of simulation analysis are given.

Energy Consumption and Efficiency Measurements of Different Excavators: Does Hybridization Pay?

2015 ◽  
Author(s):  
Arnold Hießl ◽  
Rudolf Scheidl
Keyword(s):  
Hydraulic System ◽  
Combustion Engine ◽  
Total Efficiency ◽  
Hydraulic Systems ◽  
Standard Data ◽  
Load Sensing ◽  
System States ◽  
Information Basis ◽  
Recoverable Energy ◽  
Total Inflow

A series of detailed measurements of various mechanical and hydraulic system states of different excavators was performed. Main purpose of this study was to obtain a reliable information basis for assessing the potentials of hybrid drives, in particular the amount of recoverable energy. Differences concerned the size (tonnage) of the excavators and the hydraulic systems, open center versus load sensing. All machines were tested at the same set of operation scenarios, which are typical for practice, and with different operators. To this end, all test machines have been equipped with pressure, flow rate, temperature, angular and position sensors. These signals (about sixty) and several available from the machines CAN bus were recorded with a standard data acquisition system and electronically stored for later analysis. These raw data were processed to obtain the interesting data, like speeds, power flows, energies. In addition, videos of each test were recorded to facilitate the correct interpretation of the measurements and their correlation with the actual working processes. Power flows from the combustion engine, different pumps, and at each actuator and energetic losses at the different loss sources were plotted for the different operation scenarios. Total efficiencies of the machines for different scenarios and the energy in and outflow at each actuator were computed. From the latter so called relative and absolute recovery degrees for each actuator and for the total machine in the different operation scenarios were derived. The relative recovery degree is the ratio of the total outflow energy (second and fourth quadrant) and the total inflow energy (first and third quadrant). The absolute recovery degree is the ratio of the total outflow energy of an actuator and the total energy delivered by all pumps in an operation scenario. In most operation scenarios the total efficiency of consumed mechanical output energy at the hydraulic actuators relative to delivered hydraulic energy is in the range 15% to 25%. Reasonable recovery potentials do have the swing and the boom drive. For small machines, however, the boom drive dominates.

The Principle of a Novel Load Sensing Hydraulic System and Design of the Electronic Control System

2012 ◽  
Vol 233 ◽  
pp. 119-122
Author(s):  
Yan Jie Li ◽  
Tian Yu Cui ◽  
Ji Hai Jiang ◽  
Cai Xin Yu
Keyword(s):  
Control System ◽  
Hydraulic System ◽  
Control Function ◽  
Experimental Studies ◽  
The Novel ◽  
Electronic Control ◽  
Load Sensing ◽  
Electronic Control System ◽  
Electronic Load ◽  
Control Principle

Abstract. Based on the load-sensing control principle, a novel type of electronic load sensing hydraulic system was developed. Taking a two-loads system for example, the design and analysis of the novel hydraulic system principle was completed and an electronic control system was accomplished using TTC60 controller. A preliminary experimental study was completed. The experimental studies show that the new system can not only achieve the traditional load-sensing control function, but also improve the level of electronic control system.

Demonstration of Efficient Energy Recovery Systems Using Digital Displacement® Hydraulics

2020 ◽  
Author(s):  
John Hutcheson ◽  
Daniel Abrahams ◽  
Jill Macpherson ◽  
Niall Caldwell ◽  
Win Rampen
Keyword(s):  
Energy Recovery ◽  
Mechanical Energy ◽  
Energy Output ◽  
Hydraulic Systems ◽  
Round Trip ◽  
System Architectures ◽  
Controlled Systems ◽  
Recovery System ◽  
Future Challenges ◽  
Actuator Control

Abstract Heavy off-road vehicles using conventional hydraulic systems waste significant energy through the throttling of fluid to control the motion of their actuators. This paper demonstrates how Digital Displacement® Pump Motors (DDPMs) can be used to enable efficient hydraulic energy recovery systems for these vehicles by controlling the motion of actuators directly without the need of throttling. Experiments were carried out on a test rig consisting of a 10 tonne boom supported by a hydraulic ram designed to mimic the setup of a heavy off-road vehicle. In order to demonstrate the DDPM’s potential for energy recovery systems the round-trip efficiency was measured by lifting and lowering the boom. The round-trip efficiency was taken to be the ratio of the mechanical energy output from the DDPM, when motoring to lower the boom, to the mechanical energy input to the DDPM, when pumping to raise the boom, over a known ram extension. The results showed measured round-trip efficiencies of between 63% and 87% over a range of pressures, shaft speeds and displacement fractions. Measured data obtained during the test was used to simulate the test using different system architectures and components to determine the energy efficiency. Both load sense and displacement controlled systems were simulated using both swashplate and Digital Displacement pumps. Comparison showed that the Digital Displacement systems used between 1.1 and 10.8 times less energy than the equivalent swashplate based systems. This work forms the basis for further development of energy recovery system architectures using DDPMs. Future challenges include development of the actuator control valves and transformers required to implement such systems.

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