Valve Actuation Research Articles

Obtaining Kinetics From Continuous Processes: Sampling Multiple Time Points Concurrently With a Single Valve Rotation

AbstractThe manufacturers of fine chemicals and pharmaceuticals are beginning to accept flow chemistry as a production alternative following the lead of commodity chemical manufacturers, who have been producing goods in continuous format for decades. The ability to trace time backwards by retracting the spatial length of a flow reactor is perhaps one of the biggest advantages of flowed synthesis. However, in the absence of an appropriate tool that would allow scientists to sample throughout the entire space of a production line, the theory is not possible to put into practice. A step in this direction has been taken with the invention of a unique, multi‐port valve/flow reactor that allows the chemist to simultaneously sample multiple timepoints of a chemical transformation with one single valve actuation, thereby capturing instantaneously the entire reaction course of the flowed chemical process.

Influence of compliance, and effective orifice discharge coefficient on performance of a hydroacoustic projector

A hydroacoustic projector is a compact device which converts pressure energy of fluid into low frequency sounds. It uses a direction control valve with time varying opening to periodically reverse the direction of flow. Its performance is strongly influenced by oil’s effective bulk modulus, and coefficient of discharge (Cd) of orifices in the valve. Such dependence is fundamentally different in nature from that in systems with unidirectional oil flow and constant valve opening. Thus, there is a need to study such effects in a hydroacoustic projector. For this we have developed a validated multi-physics model of the system. In most hydraulic systems, direction control valves are on–off arrangements. However, in our case the valve opening varies with time at different frequencies, and amplitudes. Thus, we have developed a method to characterize effective Cd for such orifices. Our work shows that Cd is a strong function of pressure difference across the valve, frequency of valve actuation, and valve motion amplitude. We have accounted for such dependencies in our projector model. We have also investigated the effect of increase in effective compliance of hydraulic oil on projector’s behavior, which can occur due to the presence of compliant pipes or air in the oil. We show that such an increase can drastically degrade projector’s performance. Hence, using steel pipes and reducing air content in oil can significantly improve projector performance, particularly at post-resonance frequencies.

Fluidic Platforms Incorporating Photo-Responsive Soft-Polymers Based on Spiropyran: From Green Synthesis to Precision Flow Control

In this paper, we describe how to create simple fluidic systems incorporating soft polymer actuator valves, that can provide highly precise control of flow rates in fluidic channels as an example of a 4D-materials based platform. The particular approach we describe employs photoresponsive gels that swell/contract via a light stimulus, enabling flow behavior to be controlled from outside the fluidic platform in a completely remote and non-contact manner. An improved synthesis of the spiropyran molecular photoswitch that delivers high yields (77%) using scalable green chemistry is described, along with details on how to build the valve structures in custom designed sites within the fluidic system. Fabrication of a demonstrator fluidic system incorporating up to four valves is described, along with electronics and in-house developed PID control software for achieving precise control of flow in the channels using LEDs. The resulting system demonstrates an innovative approach to microfluidics that offers scalability in terms of the number of polymer actuators along with wide variability of actuator form and function.

The effects of natural gas composition on conventional dual-fuel and reactivity-controlled compression ignition combustion in a heavy-duty diesel engine

The use of natural gas (NG) in dual-fuel heavy-duty engines has the potential to reduce pollutant and greenhouse gas (GHG) emissions from the transport sector when compared to the conventional diesel engines. However, NG composition and methane slip are of interest because both can adversely affect the benefits of NG as an alternative fuel, especially when considering GHG emissions. Therefore, this study experimentally investigated the effects of NG fuel properties on the performance and emissions of both conventional dual-fuel and reactivity-controlled compression ignition (RCCI) engine operations. Three different gas mixtures were selected to simulate typical NG compositions available in the world market, with methane numbers (MN) of 80.9, 87.6 and 94.1. These fuels were tested in a single-cylinder compression ignition engine operating at 0.6, 1.2 and 1.8 MPa net indicated mean effective pressure (IMEP). A high-pressure common rail system allowed for the use of various diesel injection strategies while a variable valve actuation system enabled the effective compression ratio to be adjusted via late intake valve closing (LIVC). The RCCI combustion was found to be more sensitive to changes in MN than the conventional NG-diesel dual-fuel operation. The gas mixture with the lowest MN reduced both total unburned hydrocarbons emissions and methane slip at the expense of higher nitrogen oxides (NOx) emissions. The effects of MN on the net indicated efficiency were more significant at 0.6 MPa IMEP, yielding differences of up to 4.9% between the RCCI operations with the lowest and highest MN fuels. Overall, this work revealed that the combination of the RCCI combustion and LIVC can achieve up to 80% lower methane slip and NOx emissions and relatively higher net indicated efficiency than the conventional dual-fuel regime, independent of the NG composition.

Performance and power consumption optimization of a hydraulic variable valve actuation system

A Hydraulic Variable Valve Actuation (HVVA) system is studied in this work, it can continuously adjust engine valve timing and lift at any engine speeds by using a hydraulic actuation system. A detailed co-simulation model is built to reveal relationship between hydraulic pressure, engine valve lift and power consumption, it has taken flow rate, fluid property and pressure drop into consideration. Precision and accuracy of the simulation model are verified by a set of bench test. Coefficient of variation (COV) of engine lift shows that the experiment is repeatable and system robustness is verified through simulation. A modified simulated annealing optimization is conducted to search optimum operation parameters to reduce the HVVA system's power consumption and improve engine's volumetric efficiency (VE) as well as control engine valve seating speed. A pre-selecting criterion and a database retrieve process are added in the algorithm to improve the optimization's efficiency. Optimization shows that optimum pump speed and relief pressure vary from 440 rpm, 32 bar to 2200 rpm, 60 bar when engine speed increases from 500 to 3600 rpm. Corresponding system power consumption rises from 0.07 kW to 0.49 kW, valve lift has a relatively high time-area value (TAV) and an acceptable engine valve seating speed.

Incorporation of Fluid Compressibility into the Calculation of the Stationary Mode of Operation of a Hydraulic Device at High Fluid Pressures

This paper is concerned with assessing the correctness of applying various mathematical models for the calculation of the hydroshock phenomena in technical devices for modes close to critical parameters of the fluid. We study the applicability limits of the equation of state for an incompressible fluid (the assumption of constancy of the medium density) to the simulation of processes of the safety valve operation for high values of pressures in the valve. We present a scheme for adapting the numerical method of S. K. Godunov for calculation of flows of incompressible fluids. A generalization of the method for the Mie – Grüneisen equation of state is made using an algorithm of local approximation. A detailed validation and verification of the developed numerical method is provided, and relevant schemes and algorithms are given. Modeling of the hydroshock phenomenon under the valve actuation within the incompressible fluid model is carried out by the openFoam software. The comparison of the results for the weakly compressible

High-resolution integrated piezoresistive sensors for microfluidic monitoring.

Microfluidic devices are traditionally monitored by bulky and expensive off-chip sensors. We have developed a soft piezoresistive sensor capable of measuring micron-level strains that can be easily integrated into devices via soft lithography. We apply this sensor to achieve fast and localized monitoring of pressure, flow, and valve actuation.

Electrowetting valves for sweat-based microfluidics

Skin-compatible microfluidic valving systems with on-demand sweat capture are necessary to understand the temporal variation of biomarkers. Here, we demonstrate solution-based electrowetting valves with rapid actuation integrated into a flexible microfluidic sweat collection patch. The valve is produced by inkjet-printing a pair of silver electrodes with spacings of 0.2–2 mm and modifying the downstream electrode with a hydrophobic self-assembled monolayer. To complete the valve, a microfluidic channel is fabricated from laser ablation of adhesive layers and pressed over the silver electrodes. Artificial perspiration is driven by capillary action within the channel until stopped by the electrowetting valve. A low voltage is applied to the electrodes, decreasing the surface energy of the hydrophobic monolayer and allowing the fluid front to continue through the microchannel. Statistical analysis demonstrated that applied voltage, and not electrode spacing, influenced valve actuation time, with 17 ± 8 s for 4 V and 40 ± 16 s for 1 V. Inkjet-printing conditions were also optimized to achieve a valve fluid retention time of 9 h. Using four electrowetting valves, an integrated wearable device is designed for artificial perspiration collection through valve actuation at distinct time points over 40 min. Finally, these inexpensive, user-friendly, and disposable electrowetting valves offer exciting opportunities for non-invasive point-of-care sweat monitoring.

Low-Cost Embedded Real-Time Handheld Vibration Smart Sensor for Industrial Equipment Onsite Defect Detection

In recent years, many industrialfacilities have been required to install sensing system to monitor the health status of the equipment. Although the PC-based diagnosis system is a good alternative, it undoubtedly increases the hardware cost greatly, and also causes restrictions on system assembly. In some critical environments, installation of the PC-based system is not suitable because of high temperature, dust, and humidity. On the contrary, a high mobility portable smart sensor will be relatively adequate for onsite inspections. To solve this problem, we developed a low-cost embedded handheld smart sensor. Instead of using sophisticated algorithms, certain frequently used statistic indicators are considered. Nevertheless, due to the resource limitations of the embedded systems, it causes difficulty for real-time realization and therefore, the recursive architecture of the statistic indicators is derived. These statistical factors are then fed into a Gaussian classifier for online defect detection, which gives a great contribution to field operators for onsite inspections. The highly integrated hardware/software co-design of the developed device provides user-friendly and high mobility for field inspections. Finally, a practical industrial application regarding the online diagnosis of a solenoid valve actuator defect is presented to demonstrate the effectiveness of the developed embedded smart sensor.

Development of a new mechanical electro hydraulic valvetrain system

Variable valve actuation (VVA) technologies can provide improvements in fuel economy of spark-ignition (SI) engines by shifting valve timings or generating valve profiles that can minimize pumping loss. Electro hydraulic valve (EHV) is one of VVA technologies that is highly flexible in producing valve profiles to control charge mass without throttle. In this work, a new EHV which has a unique operating mode, namely mechanical mode, is introduced. The mechanical mode enables operation of valvetrain under circumstances of EHV malfunctions: the mechanical electro-hydraulic valvetrain (MEHV) developed in this study was capable of stable operation under various operating modes at wide ranges of oil temperatures and cam speeds with appropriate valve seating velocity and ramp duration. The MEHV is a VVA technology that can resolve issues of previous EHVs which lacked reliability under emergency conditions.

Mechanically Closed Loop Gearbox Test Rig Controller

Most of the techniques used to monitor and diagnose faults from machines are usually based on additional measurements which require high setup costs and installation difficulties. This paper focuses on developing controller of a new method to monitor and detect problems of a gearbox transmission system based on the parameters acquired from control systems. The control data which are usually available in most of machines, including actuator current and valve flow, equivalent tensional stiffness, rotary inertia, load set point, speed demand, motor current and torque feedback have been explored based on gearbox test system[1]. Electro hydraulic actuators are widely applied in several engineering fields. However, their design is not a simple task since it is necessary to observe their behavior according to control theory. A nonlinear regression model is adopted to simulate the test condition and survey the results in the present of disturbances and any kind of interferences. The objective of this study was to obtain physical model of an electro- hydraulic actuator and provide the electro-hydraulic system which depends on the hydraulic actuators to meet the motion control system demands. However, their design is not a simple task since it is necessary to observe their behavior according to control theory. The core of the paper depends on comparing the results of two corresponding control methods (On-Off control and PID control) and the impact of the noise into the control input signal. The results confirm that the PID controller modifies the response even in presence of the noise in control input signal in accuracy, rise time, settling time, and speed.

A New Method for Ship Control Valve Overload Protection in Complex Marine Environments

Xie, Y.; Li, C.; Wang, Y., and Dong, Q., 2020. A new method for ship control valve overload protection in complex marine environments. In: Hu, C. and Cai, M. (eds.), Geo-informatics and Oceanography. Journal of Coastal Research, Special Issue No. 105, pp. 228–232. Coconut Creek (Florida), ISSN 0749-0208.The marine environment is complex and always changing, which brings additional load to ship's control valves. When subjected to additional load, the ship's control valves can break or operate abnormally, resulting in valve external leakage, which might lead to a marine environmental disaster. To avoid potential environmental pollution, control valves should have overload protection. To address the shortcomings of traditional valve overload protection methods, an all-electronic overload protection method is proposed. The method is based on the principle that the valve actuator always works to overcome the load torque, and the electromagnetic torque of the actuator motor has a one-to-one correspondence to the valve load. Therefore, calculating the actuator load based on the electromagnetic torque of the motor enables the valve to determine its load. Based on the load, the valve controller's built-in diagnostic program can achieve self-diagnosis and instigate emergency overload protection actions. This all-electronic overload protection has strong anti-interference ability, is not subject to the wear and fatigue of mechanical parts, and has an ability to withstand large loads. The experimental results demonstrate the effectiveness of the proposed overload protection method.

Method of calculating the fluid power drive of pneumatic motor inlet valve

Introduction. Hybrid power plants with a pneumatic motor, which operates at low speeds, are widely used, and an internal combustion engine is used on the rest of the speed range. Due to limitations in the regulation of valve timing in standard mechanical engine valve actuators, the possibility of using a fluid power drive for the pneumatic motor inlet valve is considered. A feature of such a fluid power drive is the use of a directional control valve with electromagnetic proportional control, which, in combination with an electronic unit, provides flexible control of the phases of air distribution in a pneumatic motor. Problem. Based on the analysis of the literature and preliminary developments, the electro-hydraulic drive of the air distribution mechanism was selected at KhNAHU, which allows not only to improve the filling characteristics, but also to carry out 2 or 4-stroke operation of the hybrid power plant.Evaluation of the capabilities of modern hydraulic control systems for speed showed that throttling servo-valve and valve with proportional electromagnets have high-frequency and speed-adjustable ones. When choosing the latter as the intake valve actuator, a static calculation of the parameters of the pumping unit is necessary. Method. The basis for solving static problems in the field of a volume hydraulic drive is the Pascal law for the working fluid in a confined space, the continuity equation of the working fluid and the third law of Newtonian mechanics, as well as the dependences of power losses due to friction forces and leaks in the gaps of precision pairs. The practical results. The diameter and speed of the valve follower movement, the consumed flow rate of the working fluid at a given speed, the pump discharge pressure, the leakage of the working fluid in the slotted seal of the plunger and the friction force are determined. The results obtained are the basis for choosing a pump and hydraulic equipment for a particular fluid power drive and conducting further dynamic calculations in order to identify the amplitudes and nature of the oscillatory processes during opening, steady state and closing the inlet valve of the pneumatic motor.

Design and Analysis of a Fully Variable Valve Actuation System

With the problem of environmental pollution and energy shortage becoming more and more serious, the fuel efficiency of automobile engines has attracted much attention, and variable valve technology is one of the important technologies to solve this problem. A novel fully variable valve actuation (FVVA) system based on a brushless direct current motor (BLDCM) is designed to achieve fully variable valve adjustment. The system uses a crank-moving guide rod mechanism to convert the rotary motion of the BLDCM into the linear motion of the valve. The fully variable valve system can realize real-time continuous adjustment of valve operating parameters through the motion control of BLDCM, including variable valve timing, variable valve opening duration, and variable lift. A BLDCM and a transmission mechanism for the FVVA system is designed in this paper. In order to better analyze the performance of the system, a dynamic model is established. Then, a three closed-loop control method is adopted to realize position control of the valve. Finally, a complete system model is established to verify the theory conclusions. The results show that the system can realize fully variable valve adjustment.

Global Synchronous Optimization Including Intake Valves and Exhaust Valves Based on MODM Strategy

Fully variable valve actuation (FVVA) technology can improve engine performance by changing engine valve timing and valve lift in different conditions. To find the optimal valve profile parameters, engine power and emissions have to be taken into account due to the contradiction between them. Therefore, the paper presented a multi-objective decision making (MODM) strategy for valve profile parameters optimization. All profile parameters both intake valves and exhaust valves were optimized synchronously. We carried out the global synchronous MODM strategy with the Radial Basis Function (RBF) response surface method (RSM). First, a FVVA system was introduced. For the FVVA system, all valve profile parameters are variable. Second, based on GT-suite, an engine model was built and its valve sub-models were rebuilt to achieve the FVVA system. Some simulation results were used to train RSM. Third, based on the simulation results, engine valve parameters were analyzed and some response surface methods were compared. The results show that RBF method has a good agreement with simulation results. At the end, global MODM strategy which optimized both intake valves and exhaust valves synchronously for engine valve parameters was implemented at 2400 RPM based on Non-dominated Sorting Genetic Algorithm (NSGA-Ⅱ) and RBF response surfaces obtained. With the obtained response surfaces, multi-objective virtual optimization which is relied on the obtained response surfaces rather than the GT-suite model was carried out. The virtual optimization results show that engine power can be improved by 1.63%, and the engine NOX emissions can be reduced by 2.75%. To verify the virtual optimization results, we carried out the simulation with the optimized parameters, and the virtual optimization results have a good agreement with results which were obtained from the simulation of the GT-suite model. Besides, the RSM-based virtual multi-objective optimization keeps faster optimization speed.

Environmental testing for TRL 4 qualification of a novel subsea valve actuator for ultra-deep water applications

Environmental testing for TRL 4 qualification of a novel subsea valve actuator for ultra-deep water applications

Characterization of energy consumption of new piezo actuator system used for hydraulic on/off valves

This paper presents a newly developed four-way digital piezo valve system composed of four high-response on/off piezo valves. The main part of the new on/off piezo valves introduces the piezo actuator system, which can be used instead of conventional solenoids. One of the important aspects related to the energy consumption of hydraulic linear drives is the use of energy-efficient hydraulic valves that require low switching energy and low holding power consumption. The first part of the paper presents the theoretical background of piezo technology, which is very important for understanding the properties of piezoelectric actuators. It is followed by a detailed description of the new piezoelectric actuator system used in on/off valves and four-way digital piezo valve system. The main part presents a thorough experimental analysis of the electrical energy consumption of the new piezoelectric actuator system, which can be used both as an actuator of hydraulic high-response on/off valves as well as an energy-efficient micropositioner. To validate the electrical switching energy and the holding power consumption of the new piezoelectric actuator system, several existing on/off valves were used as reference. The experimental analysis shows a huge reduction of electrical energy consumption when using the new piezo actuator system for hydraulic on/off valve actuation. Especially the holding power consumption in the stationary active state is about 6 times lower compared to other hydraulic on/off valves.

4D printing of shape memory polymer via liquid crystal display (LCD) stereolithographic 3D printing

In this study, we report a new epoxy acrylate based shape memory polymer (SMP) fabricated by Liquid crystal display (LCD) Stereolithographic 3D printing. The printed 3D object has a high resolution and high transparency in visible light region. The uniaxial tensile tests showed enhanced tensile toughness and tunable mechanical properties. The fix-recovery and cycle tests indicated high shape recovery properties including high shape recovery rate and excellent cycling stability. In addition, a smart electrical valve actuator was fabricated that can be used in fast heat or electricity responsive electrical circuits. LCD 3D printing provides a low-cost and high efficient way to fabricate fast responsive SMP, which can be used in wide applications in various fields on aerospace engineering, biomedical devices, soft robots and electronic devices.

Capillary stop valve actuation by thermo-pneumatic- pressure for lab-on-chip systems

A novel method is presented for triggering a robust capillary stop valve fabricated in silicon using the thermal expansion of trapped air bubble (with a footprint of just 300 μm × 320 μm) as the actuation element. A heating element on the backside of a bubble trap chamber is utilized for thermal expansion of the air bubble. A voltage pulse of around 6 V, the capillary barrier, around 1400 Pa was easily breached. A non-dimensionalized model has been developed using equivalent circuit model to describe the complex thermal/hydraulic behavior of the system. The trapped gas bubble temperature is input as a function of time in the model. A thermal finite element-based simulation is conducted to determine the gas temperature from the experimentally measured heater temperature. The model results are validated against experiments to aid in characterizing the dynamics of the problem.

Development of a Variable Valve Actuation Control to Improve Diesel Oxidation Catalyst Efficiency and Emissions in a Light Duty Diesel Engine

Growing interest has arisen to adopt Variable Valve Timing (VVT) technology for automotive engines due to the need to fulfill the pollutant emission regulations. Several VVT strategies, such as the exhaust re-opening and the late exhaust closing, can be used to achieve an increment in the after-treatment upstream temperature by increasing the residual gas amount. In this study, a one-dimensional gas dynamics engine model has been used to simulate several VVT strategies and develop a control system to actuate over the valves timing in order to increase diesel oxidation catalyst efficiency and reduce the exhaust pollutant emissions. A transient operating conditions comparison, taking the Worldwide Harmonized Light-Duty Vehicles Test Cycle (WLTC) as a reference, has been done by analyzing fuel economy, HC and CO pollutant emissions levels. The results conclude that the combination of an early exhaust and a late intake valve events leads to a 20% reduction in CO emissions with a fuel penalty of 6% over the low speed stage of the WLTC, during the warm-up of the oxidation catalyst. The same set-up is able to reduce HC emissions down to 16% and NOx emission by 13%.