The powertrain efficiency deeply affects the performance of off-road vehicles like wheel loaders in terms fuel economy, load capability, smooth control, etc. hydrostatic transmission (HST) systems have been widely adopted for providing large power density and continuous variable yet using relatively low hydraulic components. This paper presents a hydrostatic-mechanical split (PST) solution 10-ton loader improving economy loader. A directly-engine-coupled HST same is also presented...

A computationally inexpensive magnetic equivalent circuit (MEC) improves axisymmetric electromagnet design and modeling tools by accurately capturing fringing leakage effects. Lumped parameter MEC models are typically less accurate for electromagnetic devices than distributed finite-element (FEMs). However, require significantly computational time to solve FEMs therefore lend themselves applications where solution is critical, such as in optimization routines, dynamic simulation, or...

The goal of this paper is to describe a method for modeling high speed on/off valves. This model focuses on the nonlinearities electromagnetic, fluidic, and mechanical domains, specifically within solenoid driven poppet style By including these nonlinearities, accurately predicts valve transition time different driving voltages strokes. also fluid transients such as pressure ripple. Unique attributes are inclusion effect eddy currents fringing while still being fully coupled with domains. A...

This work presents the modelling and testing of a Virtually Variable Displacement Pump (VVDP). The system used high speed on/off valve to modulate flow from fixed displacement pump, directing either tank or pressure supply line hydraulic system. A lumped parameter model was developed using sub-models describe dynamics each component in test setup currently available components built validate overall study effects switching frequency on efficiency. Once verified, simulate further changing...

One major challenge in fluid power is the improvement and optimization of efficiency mobile hydraulic systems. Conventional systems often exhibit relatively low overall efficiencies caused by inefficiencies various components, such as a prime mover, variable displacement pump, valves, fittings, hoses, actuators. While each component contributes to losses system, pump converts mechanical shaft energy from mover transmitted hydraulically one most crucial components impacting system efficiency....

Current state of the art variable displacement pump/motors have high efficiencies when operating at displacements. However, as pump/motor is reduced, efficiency significantly decreases. Digital aim to increase and range operation fluid power system by minimizing leakages, friction losses compressibility losses. It based on concept actively controlling speed on/off valves connected each piston cylinder chamber. This work involves development a coupled dynamic model digital hydraulic that...

Valve dynamics play an important role in existing fluid power systems and are key enablers to a wide range of digital hydraulic systems. Varying the electrical input signal solenoids is used improve dynamic performance response times on–off valves by reducing eddy currents coil inductance. This work examines effects peak-and-hold reverse current driving strategies on two commercially available direct actuated valves, resulting impact efficiency pump/motor. An electric circuit was designed...

Abstract. Hydraulic systems are prevalent in agricultural machinery and equipment can be found transmitting power for vehicle drive wheels, powering attachments, controlling motion (booms, steering, load height, etc.). Agricultural applications of fluid have advanced terms capability efficiency, but opportunities remain significant improvements noise reduction, reliability. The average system-level hydraulic efficiency current mobile machines is only 21.1%. Because nearly all use pumps to...

In many dynamic systems, such as vehicles, engine air and fuel control fluid power industrial robotics, testing machines, high-speed actuators are necessary to achieve efficient system operation high bandwidth performance. This article introduces a new actuation mechanism enable actuation. The premise for this is momentarily couple moving component (kinetic energy source) with translational components, which enabled by coupling/clutch system. kinetic source (flywheel, electric motor, pump or...

Digital fluid power has gained substantial attention in the last decade and recently been focus of several conferences. Recognizing that digital hydraulics is an enabling technology for many new high-efficiency novel hydraulic systems, this paper demonstrates cannot simply be treated as extension well-accepted electronics domain due to some key differences between electrical systems. incorporates similar ideas those from with a goal reducing energy losses caused by throttling typical A good...

There has been a rapid increase in the use of technology university classrooms. Many classrooms and laboratories include an overhead projection unit, computer, connections for laptops. More recently, tablet PCs have investigated as another way to effectively engage students classroom environment. This study summarizes results student surveys comparing three different lecture delivery methods: using complete PowerPoint slides handouts, traditional chalkboard lectures without skeleton...

A comparative study of system-level performance is given for on/off valve control a hydraulic cylinder. dynamic model was created and simulated to develop evaluate innovative strategies specific the use valves. Cylinder position investigated using configuration consisting two 3-way valves with four 2-way Controllers were developed minimize influence on cylinder responses. All controllers configurations experimentally tested compared simulation results. sensitivity analysis performed by...

Research was completed to investigate the use of high-speed on\off valves in control a hydraulic actuator. This work as part efforts improve accuracy and smoothness travel for six-degree-of-freedom testing machine. A mathematical representation system developed that correctly predicted experimental results when single command pulse sent valves. For experiments involving series pulses simulated generally agreed at lower duty cycles, however, higher cycles there some separation due assumptions...

Digital hydraulics is an emerging field in fluid power, complementing conventional hydraulic and potentially improving efficiency dynamic performance. High speed electrically controlled on/off valves are key enablers for many digital systems, specifically pump/motors. This work investigates a 4-quadrant 3-piston pump/motor utilizing two high per displacement chamber. The test unit was simulated, built, experimentally tested. Simulation experimental results showed the importance of valve...

Hydraulic pumps can be fixed or variable displacement. Fixed displacement are typically smaller, lighter, less expensive, and of any design (gear, vane, axial piston, radial ect.)[1]. Variable often piston with an adjustable swash plate. A virtually pump (VVDP) is a combined fast switching control valve that performs the same function as pump. This done by always pumping full flow, but using to divert only certain percentage flow system, rest back tank. VVDP has several advantages over...

Valve characteristics are an essential part of digital hydraulics. The on/off solenoid valves utilized on many these systems can significantly affect the performance. Various factors speed causing them to experience various delays, which impact overall performance hydraulic systems. This work presents development adaptive statistical based thresholding real-time valve delay model for Pump/Motors. proposed method actively measures delays in and adapts threshold system with goal improving...

High speed valves have an important role in many existing fluid power systems and are enabler for proposed digital hydraulic systems. One method commonly used to improve the dynamic performance of on-off involves modifying electrical input signal solenoids reduce inductive lag eddy current decay. This research examined two commercially available direct actuated pilot-stage cartridge poppet peak-and-hold voltage reverse profiles on opening closing switching times. A test stand was built...

Digital hydraulics is a technology gaining perceptible growth in fluid power research. The advantages of digital systems can be realized through improved system efficiencies, energy savings, increased productivity, and performance compared to traditional systems. Conventional check valve pumps use differential pressures deliver pressurized flow the system. enable conventional achieve variable displacements by enhancing controllability inlet outlet valves hydraulic technologies techniques....

Magnetic pressures on nonlinear steel are shown to have lower values than typical hydraulic and, thus, small magnetic actuators often coupled circuits. A new method of modeling a electrical/magnetic/hydraulic/mechanical system is described. Results electromagnetic finite-element analysis actuator used in SPICE circuit that contains the differential equations valve, cylinder, and mechanical load. The model compute transient pressures, flows, motions. Due fluid flow forces mass controlled arm...