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

Author(s):  
Arnold Hießl ◽  
Rudolf Scheidl

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.

Author(s):  
Milos Vukovic ◽  
Sebastian Sgro ◽  
Hubertus Murrenhoff

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.


Author(s):  
Shuzhong Zhang ◽  
Tatiana Minav ◽  
Matti Pietola

Government regulations incentivize investigation of the potential for hybridization of non-road mobile machinery (NRMM). Many approaches to energy saving in hydraulic systems have been established. One of the methods first introduced in the aerospace industry is “decentralized” or “zonal” hydraulics. The decentralized system is realized with pump-controlled actuators, which are distributed throughout the system. In this research, decentralized hydraulics are realized with a direct-driven hydraulics (DDH) drive and implemented on a 1-ton class JCB micro excavator. The original valve-controlled system for boom, stick, and bucket is replaced with three DDH units. In a DDH unit, a double fixed displacement pump/motors with a speed-controlled electric servomotor directly controls the amount of hydraulic oil pumped into and out of the system. The hydraulic pump/motors create flows dependant on the rotating speed of the servomotor. A hydraulic accumulator is used as a conventional tank replacement. The aim of this paper is to investigate the efficiency improvement of the excavator with decentralized hydraulics compared to an electrified conventional load sensing system, from an energy consumption point of view under a typical digging cycle. In order to acquire the energy consumption distributions of the DDH and load sensing (LS) system, a model of the micro excavator which comprises mechanics, hydraulics, electronics, and control systems is developed in Matlab/Simulink. Simulation results demonstrate that the total efficiency of the excavator with LS control is 18.3%, and with DDH (decentralized hydraulics) is 71.3 % for a selected typical working cycle.


2011 ◽  
Vol 317-319 ◽  
pp. 307-313 ◽  
Author(s):  
Cong Mei Wei ◽  
Jin Yi Lian ◽  
Jing Jie Li

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.


Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4410
Author(s):  
Albert Gareev ◽  
Vladimir Protsenko ◽  
Dmitriy Stadnik ◽  
Pavel Greshniakov ◽  
Yuriy Yuzifovich ◽  
...  

This paper examines the effectiveness of neural network algorithms for hydraulic system fault detection and a novel neural network architecture is suggested. The proposed gated convolutional autoencoder was trained on a simulated training set augmented with just 0.2% data from the real test bench, dramatically reducing the time needed to spend with the actual hardware to build a high-quality fault detection model. Our fault detection model was validated on a test bench and showed accuracy of more than 99% of correctly recognized hydraulic system states with a 10-s sampling window. This model can be also leveraged to examine the decision boundaries of the classifier in the two-dimensional embedding space.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2707
Author(s):  
Luis Javier Berne ◽  
Gustavo Raush ◽  
Pedro Javier Gamez-Montero ◽  
Pedro Roquet ◽  
Esteban Codina

In recent years, much research has focused on reducing the power consumption of mobile hydraulic machines due to rising fuel costs, regulations on combustion engine emissions and the need to reduce the size and weight of the storage devices in hybrid drives. Current approaches to improve the energy efficiency of a hydraulic system can be classified into four basic groups: reduction of the energy demand, recovery of part of the supplied energy (ERS systems), regeneration of part of the supplied energy and reuse of the recovered and regenerated energy (hybrid systems). Today’s mobile hydraulic systems are often complex, perform different tasks and work under different load conditions, which makes it difficult to analyse energy losses. A study of the energy losses of a hydraulic system from different points of view, such as an energy balance for a complete machine cycle, an analysis of the individual cycle phases and a power analysis for the different operation quadrants of the actuators, can give an global picture of the energy losses, being very useful to rate its energy efficiency, identify main power losses and decide which of the different energy-saving techniques to apply. This paper describes the data collection process, its analysis from various points of view and the summary of the results in easy to understand charts as useful tools to identify and quantify the main energy losses. Only system architecture losses are considered. Losses in the ICE engine or the electric motor, hydraulic pump losses and mechanical losses are outside the scope of this study.


2021 ◽  
Vol 11 (7) ◽  
pp. 3033
Author(s):  
Michele De Santis ◽  
Luca Silvestri ◽  
Antonio Forcina ◽  
Gianpaolo Di Bona ◽  
Anna Rita Di Fazio

Most industrial trucks are equipped with hydraulic systems designed for specific operations, for which the required power is supplied by the internal combustion engine (ICE). The largest share of the power consumption is required by the hydraulic system during idling operations, and, consequently, the current literature focuses on energy saving strategies for the hydraulic system rather than making the vehicle traction more efficient. This study presents the preliminary realization of an electric-powered hydraulic pump system (e-HPS) that drives the lifting of the dumpster and the garbage compaction in a waste compactor truck, rather than traditional ICE-driven hydraulic pump systems (ICE-HPSs). The different components of the e-HPS are described and the battery pack was modelled using the kinetic battery model. The end-of-life of the battery pack was determined to assess the economic feasibility of the proposed e-HPS for the truck lifespan, using numerical simulations. The aim was twofold: to provide an implementation method to retrofit the e-HPS to a conventional waste compactor truck and to assess its economic feasibility, investigating fuel savings during the use phase and the consequent reduction of CO2 emissions. Results show that the total lifespan cost saving achieved a value of 65,000 €. Furthermore, total CO2 emissions for the e-HPS were about 80% lower than those of the ICE-HPS, highlighting that the e-HPS can provide significant environmental benefits in an urban context.


Author(s):  
Ken Sugimura ◽  
Hubertus Murrenhoff

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.


2021 ◽  
Vol 11 (11) ◽  
pp. 5001
Author(s):  
Robin Masser ◽  
Karl Heinz Hoffmann

Energy savings in the traffic sector are of considerable importance for economic and environmental considerations. Recuperation of mechanical energy in commercial vehicles can contribute to this goal. One promising technology rests on hydraulic systems, in particular for trucks which use such system also for other purposes such as lifting cargo or operating a crane. In this work the potential for energy savings is analyzed for commercial vehicles with tipper bodies, as these already have a hydraulic onboard system. The recuperation system is modeled based on endoreversible thermodynamics, thus providing a framework in which realistic driving data can be incorporated. We further used dissipative engine setups for modeling both the hydraulic and combustion engine of the hybrid drive train in order to include realistic efficiency maps. As a result, reduction in fuel consumption of up to 26% as compared to a simple baseline recuperation strategy can be achieved with an optimized recuperation control.


Author(s):  
Niko Karlén ◽  
Tatiana Minav ◽  
Matti Pietola

Several types of off-road machinery, such as industrial trucks, forklifts, excavators, mobile cranes, and wheel loaders, are set to be operated in environments which can differ considerably from each other. This sets certain limits for both the drive transmissions and working hydraulics of these machines. The ambient temperature must be taken into account when selecting the hydraulic fluid since the viscosity and density of the fluid are changing at different operating temperatures. In addition to the temperature, energy efficiency can also be a problem in off-road machinery. In most off-road machines, diesel engines are employed to produce mechanical energy. However, there are energy losses during the working process, which causes inefficiency in produced energy. For better energy efficiency, hybridization in off-road machinery is an effective method to decrease fuel consumption and increase energy savings. One of the possible methods to save energy with hybrids is energy regeneration. However, it means that the basic hydraulic system inside off-road machinery needs to be modified. One solution for this is to utilize zonal or decentralized approach by means of direct driven hydraulic (DDH) system. This paper aims to investigate a DDH system for off-road machinery by means of modelling and analyzing the effect of the temperature. In the direct-driven hydraulic system, the actuator is controlled directly by the hydraulic pump which is operated by the electric motor. Specifically, it is a valveless closed-loop hydraulic system. Thus, there will be no energy losses caused by the valves, and the total efficiency is assumed to be significantly higher. In order to examine the DDH system, a thermo-hydraulic model was created. Additionally, a thermal camera was utilized in order to illustrate the temperature changes in the components of the DDH system. To reproduce the action of the system in different circumstances DDH system was run at different ambient temperatures, and the component temperatures in the system were measured and saved for the analysis. The thermo hydraulic model was proven capable to follow the general trend of heating up.


2013 ◽  
Vol 418 ◽  
pp. 63-69
Author(s):  
Sema Patchim ◽  
Watcharin Po-Ngaen

In last decade, energy efficiency of hydraulic actuators systems has been especially important in industrial machinery applications [1-. And an advanced electronics world most of the applications are developed by microcontroller based embedded system. Energy processor based variable oil flow of hydraulic controller was presented to improve the efficiency of the motor by maintaining with the load sensing. These PIC processor combined with fuzzy controller were help to design efficient optimal power hydraulic machine controller. A functional design of processor and in this system was completed by using load sensing signal to control oil flow. The advantage of the proposed system was optimized operational performance and low power utility. Without having the architectural concept of any motor we can control it by using this method. This is a low cost low power controller and easy to use. The experiment results verified its validity.


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