On Energy Efficient Mobile Hydraulic Systems: with Focus on Linear Actuation

Heybroek, Kim

doi:10.3384/diss.diva-142326

Cited by 15 publications

(18 citation statements)

References 25 publications

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“…This architecture is characterized by controlling the piston motion in different modes dependent on the positions of the four 2/2 valves. This expands the operating region (force and speed) compared to single-pump closed-circuit solutions [112]. For example, is the cylinder piston retracting speed not limited by the pump size in aided load situations, because oil may also be guided to the other cylinder chamber (differential lowering) or directly to the reservoir (meter out flow control) [113].…”

Section: E3-directional Control Valvesmentioning

confidence: 99%

“…Using the proposed architecture, the pump may be downsized compared to equivalent closed-circuit architectures. The challenges for this architecture are related to the control of pump and valves required for smooth transition between operation mode and quadrant [112,115]. In [113] fuel savings of 10% to 20% compared to a conventional load sensing hydraulic system was achieved, when implemented in a wheel loader.…”

Section: E3-directional Control Valvesmentioning

confidence: 99%

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Classification and Review of Pump-Controlled Differential Cylinder Drives

et al. 2019

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Pump-controlled hydraulic cylinder drives may offer improved energy efficiency, compactness, and plug-and-play installation compared to conventional valve-controlled hydraulic systems and thus have the potential of replacing conventional hydraulic systems as well as electro-mechanical alternatives. Since the late 1980s, research into how to configure the hydraulic circuit of pump-controlled cylinder drives has been ongoing, especially in terms of compensating the uneven flow requirements required by a differential cylinder. Recently, research has also focused on other aspects such as replacing a vented oil tank with a small-volume pressurized accumulator including the consequences of this in terms of thermal behavior. Numerous references describe the advantages and shortcomings of pump-controlled cylinder drives compared to conventional hydraulic systems or electro-mechanical drives. This paper presents a throughout literature review starting from the earliest concepts based on variable-displacement hydraulic pumps and vented reservoirs to newer concepts based on variable-speed electric drives and sealed reservoirs. By classifying these drives into several proposed classes it is found that the architectures considered in the literature reduce to a few basic layouts. Finally, the paper compares the advantages and shortcomings of each drive class and seek to predict future research tasks related to pump-controlled cylinder drives. IntroductionWith an increased industrial focus on energy efficiency, plug-and-play installation, and compactness, conventional valve-controlled hydraulic cylinder drives are increasingly being replaced by electro-mechanical alternatives, such as roller or ball screws [1], especially for small power classes. This happens despite the well-known advantages of hydraulic linear actuation such as large force/power densities, reliability, and robustness. Hydraulic actuation is, however, still the preferred solution for many applications such as industrial presses, large mobile machinery, crane manipulators, primary aircraft control etc. [2][3][4]. Among other reasons this is due to certain limitations for the electro-mechanical alternatives, such as limited reliability (e.g., shock loads damage), the difficulties of implementing overload/failure protection and/or limited force capabilities [5][6][7]. To strengthen the position regarding these applications and to make hydraulic cylinder drives competitive with electro-mechanical drives for low power applications, there is a need to enhance both the energy efficiency and the overall flexibility of hydraulic cylinder drives.The flexibility of a hydraulic system may be related to how power is being distributed between the prime mover and the actuator(s). As illustrated in Figure 1, at least three different power distribution topologies exist: hydraulic, mechanical, and electrical distribution.

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Section: E3-directional Control Valvesmentioning

confidence: 99%

Section: E3-directional Control Valvesmentioning

confidence: 99%

Classification and Review of Pump-Controlled Differential Cylinder Drives

et al. 2019

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“…Hydraulic hybridisation of working machines offers several attractive features, such as kinetic/potential energy recuperation, function/system decoupling and power boost functionality [1] -features that, in turn, may lead to increased fuel efficiency, productivity and operability [2]. Compared to on-road applications, a key challenge with the hybridisation of mobile working machines is that they have several substantial power consumers: a driveline and work functions.…”

Section: Hydraulic Hybrid Working Machinesmentioning

confidence: 99%

“…Hybridisation of the working hydraulics system is possible, but presents its own challenges. This topic is not within the scope of this thesis, but has been thoroughly investigated in [1].…”

Section: Hydraulic Hybrid Working Machinesmentioning

confidence: 99%

Control of Hybrid Hydromechanical Transmissions

Larsson

2019

Linköping Studies in Science and Technology. Dissertations

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“…e.g. [30,31]), forest machinery (cf. Thiebes [12] for some developments), and material handling machines (cf.…”

Section: Applicationsmentioning

confidence: 99%

Simulation-Based Optimization of a Series Hydraulic Hybrid Vehicle

Bær¹

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"The brick walls are there for a reason. (...) [They] are there to give us a chance to show how badly we want something. Randy Pausch AbstractHybrid transmissions are characterized by their utilization of more than one form of energy storage. They have the potential to help reduce overall fuel consumption and vehicle emissions by providing the possibility of brake energy recuperation and prime mover operation management. Electric hybrids and electric vehicle drives are nowadays ubiquitous, and mechanical energy storage in flywheel has been investigated in the past. The use of fluid power technology with a combustion engine has also been investigated since the late 1970s, and is frequently revisited.Hydraulic hybridization is especially attractive for heavy vehicles with frequent braking and acceleration which benefit most from fluid power components' high power density, typically busses, delivery or refuse vehicles, and vehicles with existing hydraulic circuits and transmissions, such as forest and construction machinery, but have been considered for smaller vehicles as well.Due to the characteristic discharge profile of hydraulic energy storage, special attention needs to be paid to control aspects in the design process to guarantee drivability of the vehicle. In this respect, simulation models can be of use in early design process stages for cheaper and faster evaluation of concepts and designs than physical experiments and prototyping, and to generate better understanding of the system studied. Engineering optimization aids in the systematic exploration of a given design space, to determine limits and potentials, evaluate trade-offs and potentially find unexpected solutions. In the optimization of a hydraulic hybrid transmission, the integration of component and controller design is of importance, and different strategies (sequential, iterative, bi-level and simultaneous approaches) are conceivable, with varying consequences for the implementation.This thesis establishes a simulation-based optimization framework for a hydraulic hybrid transmission with series architecture. Component and control parameter optimization are addressed simultaneously, using a rule-based supervisory control strategy. The forward-facing dynamic simulation model at the centre of the framework is built in Hopsan, a multi-disciplinary open-source tool developed at Linköping University. The optimization is set up and conducted for an example application of an on-road light-duty truck over standard drive i cycles. Both results from these experiments as well as the framework itself are studied and evaluated. Relevant design aspects, such as explicit design relations to be considered and performance requirements for more robust design, are identified and addressed, and the optimization problem is analysed with regard to algorithm performance and problem formulation. The final result is an optimization framework that can be adjusted for further in-depth studies, for example through the inclusion of additional components or optimization obj...

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On Energy Efficient Mobile Hydraulic Systems: with Focus on Linear Actuation

Cited by 15 publications

References 25 publications

Classification and Review of Pump-Controlled Differential Cylinder Drives

Classification and Review of Pump-Controlled Differential Cylinder Drives

Control of Hybrid Hydromechanical Transmissions

Simulation-Based Optimization of a Series Hydraulic Hybrid Vehicle

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