Piston Valve Research Articles

New Modeling and Experimental Study Regarding Tungsten-Carbide-Coated Parts of the Combustion Chamber of a Compression-Ignition Engine

In this study, piston, exhaust, and intake valves of a diesel engine were coated with tungsten carbide in 300 μm thickness using the high-velocity oxygen fuel coating method. Mathematical modeling of coated and uncoated (standard) engines was performed using the artificial neural network (ANN). The purpose of this study was to decrease the number of test repetitions and reduce the test cost by performing mathematical modeling of engines through the ANN. The results obtained from the tests were input in the ANN, and values of the engines at all revolutions per minute values were estimated. The results of the tests were compared to results obtained from the ANN, and they were observed to be consistent with each other. As a result of thermal barrier coating, specific fuel consumption, hydrocarbon, carbon monoxide, and smoke density values of the diesel engine decreased, whereas NOx and exhaust gas temperature increased. Furthermore, results obtained by applying mathematical modeling through the ANN reduced t...

Experimental investigation of coating in a diesel engine for improved exhaust emissions and performance

In this study, adiabatic property was brought to a 4-cylinder natural aspirated, direct injection diesel engine. For this purpose, cylinder liner, piston upper surface and valves were coated with powder with boron. Solid-boronizing method and plasma spray method were used as coating method. While cylinder liner and valves were coated with the layer of Fe2B in the thickness of 150 micron by using solid boronizing method, piston upper surface was coated with the layer of CoNiCrAlYttra +NiCrBSi in the thickness of 300 micron by using plasma spray method. After the coating process, the engine was subject to performance and emission tests. ASTM-D-2 fuel was used as test fuel. As a result of tests, while BSFC value of coated engine decreased at the rate of 7.5% and BSEC value decreased at the rate of 7% and at the rate of 15% in EGT value. While a decrease was observed at the rate of 10% in CO value, 47% in HC value, and 14% in Smoke value, an increase was observed at the rate of 35% in NOx value.

Numerical analysis of flow and temperature characteristics in a high multi-stage pressure reducing valve for hydrogen refueling station

Hydrogen refueling station is one of the most important parts for the hydrogen energy utilization. In this paper, a novel high multi-stage pressure reducing valve (HMSPRV) is proposed, which can be used for hydrogen stable decompression in hydrogen refueling station. In HMSPRV, the inner and outer porous shrouded valve core is used to replace piston valve core to achieve the first-stage throttling, and the porous orifice plate is chosen as the second-stage throttling component. Meanwhile, in order to verify the applicability of HMSPRV, the flow characteristics of two fluids are studied. Firstly, the choked flow, flow and temperature characteristics of superheated steam under different valve openings are carried out. Secondly, the flow characteristic of hydrogen is also conducted to validate the application of HMSPRV in hydrogen refueling station. The results show that, for superheated steam flow, with the increasing of valve openings, the maximum gradient of fluid pressure moves from the fitting surface where inner and outer porous shrouded to the orifice plate. The regulation of its amount is decreasing first and then increasing. With the increasing of valve openings, the maximum velocity, turbulent dissipation rate and pressure loss are all increasing gradually, while the temperature does not change significantly. For hydrogen flow, both the pressure changing process and velocity changing process are similar to superheated steam. It can be concluded that HMSPRV has good flow and temperature characteristics in complex conditions, and it does not prone to choked flow. Throttling effect of the multi-stage pressure reducing way is obvious. This work can benefit the further research work on hydrogen stable decompression in hydrogen refueling station.

Designing an optimized model-free controller for improved motion tracking by rugged electrohydraulic system

Electrohydraulic actuation systems with proportional valves and industry-grade cylinders have widespread use due to their low cost and ease of maintenance. Achieving good tracking of output position of the piston in such a system by a proper controller design is the objective of this study. Due to various parameter uncertainties and complex nonlinearities like piston friction, valve deadband and flow characteristics, the variation of oil property with working temperature and air entrapment volume, the implementation of a model-based control becomes quite difficult for such systems. A notable contribution of this work is to couple a model-free fuzzy controller with a feedforward controller with all the parameters estimated by a real-coded genetic algorithm. Also, the optimizer has been used for identifying an appropriate fuzzy structure that is easy to implement in real time. A comprehensive experimental study has revealed the best fuzzy structure to be achieved through a Gaussian fuzzification of linear combination of the position and velocity errors as the input and singleton membership function for the output voltage actuating the proportional valve. Excellent responses with good disturbance rejection capability and energy efficiency have been achieved. These responses have emerged superior to those achieved in a similar system with different controller structures and in systems with much costlier components.

Diesel Engine Cycle Analysis of Two Different TBC Combustion Chamber

Efficient energy usage and energy conservation is the today's requirement for all researchers of IC engine. The usual method of producing heat from fuel is by the process of combustion, which is a chemical reaction between the fuel and oxidant. Thermodynamics is the science that deals with interaction between energy and material systems. In case of I C, engine about one-third of total energy is used as conversion of useful work. Diesel engine is operated at higher compression ratio, so low heat rejection engine is made by applying better ceramic TBC material. The concept of adiabatic engine is used to save the loss of energy and also minimize the exhaust emissions. Further efforts were made by computerized experimental work by using twin cylinder water cool constant speed diesel engine. The self-governed diesel engine combustion chamber components like piston's top surface, engine heads, valves and liners were fully coated with two different better TBC materials like MgZrO3 and YSZ. In both cases, TBC bond coat NiCAlY are used for better mechanical strength. The diesel combustion cycles analysis were carried and different combustion results displayed like, crank angle verses cylinder pressure, mass fraction, heat release and pressure volume diagram. The result indicates that, better combustion is found in MgZrO3 type ceramic TBC material diesel engine.

Designing locally fabricated wooden piston valves for a low-cost hand pump

Designing locally fabricated wooden piston valves for a low-cost hand pump

Testing and Modeling of an Acoustic Instability in Pilot-Operated Pressure Relief Valves

Pressure relief valves (PRVs) are included as an essential element of many compressor piping systems in order to prevent overpressurization and also to minimize the loss of process gas during relief events. Failure of the valve to operate properly can result in excessive quantities of vented gas and/or catastrophic failure of the piping system. Several mechanisms for chatter and instability have been previously identified for spring-loaded relief valves, but pilot-operated relief valves are widely considered to be stable. In this paper, pilot-operated PRVs are shown to be susceptible to a dynamic instability under certain conditions where valve dynamics couple with upstream piping acoustics. This self-exciting instability can cause severe oscillations of the valve piston, damaging the valve seat, preventing resealing, and possibly causing damage to attached piping. Two case studies are presented, which show damaging unstable oscillations in a field installation and a blowdown rig, and a methodology is presented for modeling the instability by coupling a valve dynamic model with a 1D transient fluid dynamics simulation code. Modeling results are compared with measured stable and unstable operation in a blowdown rig to show that the modeling approach accurately predicts the observed behaviors.

Performance and emission characteristics of a low heat rejection engine using Nerium biodiesel and its blends

In the present study, the surface of cylinder head, piston, exhaust and inlet valves of a four stroke direct injection and single cylinder diesel engine has been coated with partially stabilised zirconia (PSZ) by the plasma spray method. The coated engine was tested with the neat diesel and methyl ester of neat Nerium oil. The performance and emission results were compared with the uncoated engine fuelled with diesel and methyl ester of Nerium oil (MEON). Specific fuel consumption of the PSZ-coated engine was lower at all loads, because of the insulation effect of coating and changes in combustion process due to coating. The brake thermal efficiency of PSZ-coated engine fuelled with MEON is 3.8% higher than uncoated engine fuelled with MEON. The emission for the PSZ-coated engine with diesel was improved compared with uncoated engine except NOx.

Diagnostics of automatic compensators of valve clearance in combustion engine with the use of vibration signal

Dynamic development of internal combustion engines creates a need to adopt a strategy concerning operational use of these driving units based on the knowledge of their technical condition. The assessment of technical condition belongs to tasks of technical diagnostics.This article presents an analysis of issues concerning vibration diagnostics of automatic compensators of clearances in piston valves of combustion engine. Scientific experiments focused on delivering information necessary to create (and also to validate) diagnostic models enabling assessment of technical condition of those elements of combustion engine that are essential taking into account effectiveness and durability that were carried out and described here. On the basis of the worked out diagnostic model, the algorithm for assessment of the technical condition of automatic compensators of valve clearance was created.

Studies on the performance and emission characteristics of Mahua oil fuelled low heat rejection diesel engine

The world energy reserves are depleting day-by-day and the demand is increasing. This leads to search for suitable renewable alternative fuels. Among the available alternative fuels, biodiesel can be used as an immediate substitute for the diesel engine. However, the biodiesel fuelled diesel engine gives lower brake thermal efficiency due to higher viscosity and lower volatility of the biodiesel. Hence, in this work, an attempt was made to increase the performance of the biodiesel fuelled engine using ceramic coating on the engine combustion chamber components. In this experimental study, engine components such as cylinder head, piston, exhaust and inlet valves were coated with Nickel Chromium (NiCr) alloy and Yttria Stabilized zirconia (Y 2 O 3 –ZrO 2 ) of thickness 250 μm using plasma spray coating. Since mahua oil has significant potential for the biodiesel production, it was used for the biodiesel production. In this work, the engine tests were conducted on a single cylinder four stroke direct injection diesel engineand different blends were used as the fuels. The engine performance and emission characteristics were analysed by varying the load under both coated and uncoated conditions of the engine and results were compared with neat diesel. From the engine test results, it was observed that the engine performance with biodiesel blends such as B10 and B20, was increased from 3 to 7% depends upon the load on the engine with thermal barrier coating as compared to the normal engine without coating.

Improving the tribological behavior of internal combustion engines via the addition of nanoparticles to engine oils

AbstractThe friction between two sliding surfaces is probably one of the oldest problems in mechanics. Frictional losses in any I.C. engine vary between 17% and 19% of the total indicated horse power. The performance of internal combustion engines in terms of frictional power loss, fuel consumption, oil consumption, and harmful exhaust emissions is closely related to the friction force and wear between moving parts of the engine such as piston assembly, valve train, and bearings. To solve this problem, most modern research in the area of Nanotribology (Nanolubricants) aims to improve surface properties, reduce frictional power losses, increase engine efficiency, and reduce consumed fuel and cost of maintenance. Nanolubricants contain different nanoparticles such as Cu, CuO, TiO

Design and characterization of a biologically inspired quasi-passive prosthetic ankle-foot.

By design, commonly worn energy storage and release (ESR) prosthetic feet cannot provide biologically realistic ankle joint torque and angle profiles during walking. Additionally, their anthropomorphic, cantilever architecture causes their mechanical stiffness to decrease throughout the stance phase of walking, opposing the known trend of the biological ankle. In this study, the design of a quasi-passive pneumatic ankle-foot prosthesis is detailed that is able to replicate the biological ankle's torque and angle profiles during walking. The prosthetic ankle is comprised of a pneumatic piston, bending spring and solenoid valve. The mechanical properties of the pneumatic ankle prosthesis are characterized using a materials testing machine and the properties are compared to those from a common, passive ESR prosthetic foot. The characterization spanned a range of ankle equilibrium pressures and testing locations beneath the foot, analogous to the location of center of pressure within the stance phase of walking. The pneumatic ankle prosthesis was shown to provide biologically appropriate trends and magnitudes of torque, angle and stiffness behavior, when compared to the passive ESR prosthetic foot. Future work will focus on the development of a control system for the quasi-passive device and clinical testing of the pneumatic ankle to demonstrate efficacy.

Hydraulic Vibration Exciter and Hydraulic Circuit Design Research

Pressure of the liquid is used as power source of hydraulic vibration exciter. Rotary directional control valve is the realization of oiling-way veversing components . The piston is reciprocated under the influence of the change of the hydraulic. The reciprocating movement of the piston is a result of fluid pressure.Working area of the piston multiplied by the pressure of the liquid is equal to the thrust of the piston.Displacement response of the vibration exciter can be simplified to the second-order vibration systems.Elastic beam is used as limit components of piston of vibration exciter,the piston vibration waveform is a sine wave .The volume of elastic beam is smaller than the volume of fluid elastic element . The hydraulic circuit is a dual pump fuel supply circuits.Pumps are used to supply rotary valve and hydraulic cylinder .Dual pumps fuel supply system is conducive to control fluid pressure and flow of the rotary valve and vibration piston.

Performance, Combustion, and Emission Characteristics of a Low Heat Loss Diesel Engine Operated on Eucalyptus Oil and Diesel Fuel Blends

The aim of this study is to apply low heat rejection to an engine to improve engine performance using Eucalyptus oil and diesel fuel blend as a fuel. For this purpose a direct injection diesel engine was converted into a low heat rejection engine, and its performance, emission, and combustion characteristics were investigated experimentally. The experiment has been carried out on two phases. In the first phase, the blends of Eucalyptus oil and diesel fuel were injected at various loads in a direct injection four stroke TV1 Kirloskar make diesel engine. In the second phase, instead of using a single-property yttria stabilized zirconia coating to achieve the thermal barrier for the piston crown, cylinder head, and valves, a functionally graded material having a variety of properties and a layer of aluminum oxide coating was used. Thus, a thermal barrier was produced for the elements of the combustion chamber. From the results, it is observed that there will be a significant decrease in specific fuel consumption and an increase in brake thermal efficiency. Also, there is a significant reduction in carbon monoxide, oxides of nitrogen except unburned hydrocarbon emission, and smoke density for all test fuels used in the coated engine as compared to the uncoated engine.

A CFD analysis of the dynamics of a direct-operated safety relief valve mounted on a pressure vessel

In this study, a numerical model is developed to investigate the fluid and dynamic characteristics of a direct-operated safety relieve valve (SRV). The CFX code has been used to employ advanced computational fluid dynamics (CFD) techniques including moving mesh capabilities, multiple domains and valve piston motion using the CFX Expression Language (CEL). With a geometrically accurate CFD model of the SRV and the vessel, the complete transient process of the system from valve opening to valve closure is simulated. A detailed picture of the compressible fluid flowing through the SRV is obtained, including small-scale flow features in the seat regions. In addition, the flow forces on the disc and the lift are monitored and analyzed and the comparison of the effects of design parameters, are examined; including the adjusting ring position, vessel volume and spring stiffness. Results from the model allow the fluid and dynamic characteristics of the SRV to be investigated and shows that the model has great potential of assisting engineers in the preliminary design of SRVs, operating under actual conditions which are often found to be difficult to interpret in practice.

Studies on the use of low-volatile non-edible oils in a thermal barrier-coated diesel engine

Owing to the ever-increasing vehicle population, the consumption of diesel fuel in the transportation, agricultural and industrial sectors has increased at an alarming rate. This has led to rapid fossil fuel depletion, ozone depletion and environmental degradation, which have become a serious concern. Search for alternative renewable and clean energy fuel sources to mitigate the emissions of greenhouse gases is continuing, and attempts to find different techniques for efficient utilization of these fuels are also undertaken. Biodiesel being an oxygenated fuel obtained from vegetable oils has received greater attention over the years as a promising alternative to diesel fuel. However, vegetable oils exhibit high viscosity, poor volatility and poor cold-flow characteristics. These characteristics can cause the following problems in the engine when run for a longer duration: injector coking, severe engine deposits, filter gumming, piston ring sticking and thickening of lubrication. These problems can be eliminated or minimized by adopting suitable fuel processing techniques to obtain biodiesels from vegetable oils. The fuel processing techniques vary widely, which include transesterification, supercritical methanolysis, ultrasonic and continuous microwave-assisted transesterification methods. In the present study, the transesterification method is effectively used to obtain biodiesels from non-edible oils of honne and cotton seed. The biodiesels obtained from these oils were used in the unmodified diesel engine to check their feasibility as diesel engine alternatives. Different thermal barrier coatings (TBCs) were applied on the piston, cylinder head, and inlet and exhaust valve surfaces of the diesel engine in order to make it a fully adiabatic engine. The engine with such TBCs is called a low heat rejection engine. For the present study, the TBC of partially stabilized zirconia (PSZ) and aluminium oxide (Al2O3) were selected. Finally, the performance of the diesel engine fuelled with different biodiesels in both conventional and thermal barrier-coated modes was compared. The thermal barrier-coated engine with the PSZ version showed better performance with increased nitric oxide emissions when compared with the Al2O3 coating.

Performance and Emission Characteristics of Low Heat Rejection Diesel Engine Fuelled with Rice Bran Oil Biodiesel

In this study, the performance and exhaust emissions of a biodiesel fuelled low heat rejection (LHR) direct injection Diesel engine have been investigated experimentally and compared with the results of standard diesel engine without any coatings. Piston, cylinder head, exhaust and inlet valve of test engine were coated with 0.5 mm thickness of zirconia through plasma spray method. Biodiesel used in the testing was prepared from rice bran oil through transesterification process.

Comparative Study of Performance and Combustion Characteristics of Conventional and Low Heat Rejection (Mullite Coated) Diesel Engines

Tests were performed on a single cylinder, four stroke, direct injection, diesel engine whose piston crown, cylinder head and valves were coated with a 0.5 mm thickness of 3Al2O3·2SiO2 (mullite) (Al2O3 = 60%, SiO2 = 40%) over a 150 μm thickness of NiCrAlY bond coat. The working conditions for the conventional engine (without coating) and LHR (mullite coated) engine were kept exactly same to ensure a comparison between the two configurations of the engine. This paper is intended to emphasis on performance and combustion characteristics of conventional and LHR (Mullite coated) diesel engines under identical conditions. Tests were carried out at same operational constraints i.e. air-fuel ratio and engine speed conditions for both conventional engine (without coating) and LHR (mullite coated) engines. The results showed that, there was as much as 1.8 % increasing on brake power for LHR (mullite coated) engine compared to conventional engine (without coating) at full load The average decrease in brake specific fuel consumption in the LHR engine compared with the conventional engine was 1.76 % for full engine load. However, there was increasing on cylinder gas pressure and net heat release rate for LHR engine compared to conventional engine. Also the results revealed that, there was as much as 22% increasing on exhaust gas temperature for LHR engine compared to conventional engine at full engine load.

Estimation for Variation of the Damping Force Induced by the Expansive Movement of Shock Absorber

In this paper, the damping force loci of a twin tube shock absorber were estimated by using the empirical data. The variation of the damping force was investigated for movements of piston such as the expansion. The relationship between the piston velocity and the damping force were estimated by using the empirical data of four different conditions of coil spring turns. Also the relationship between the coil spring turns and the damping force were estimated by using the empirical data of four different piston velocities. Based on the experiment results, the estimated damping force variation functions provide the physical information of the components of the main piston valve system to save the manufacturing time and cost for the shock absorber

Research for Application of Save Energy Piston Valve for Water Pump Balance Control

This paper introduces new type of save energy piston valve for water pump balance control, which is save energy efficiency expert. This piston valve is designed by pneumatic theory, and drive power is delivered by air compressor or pressure air source in waterworks. Pressure air is lead into cavity of piston valve by transfer action of “two positions and five channels ” electromagnetic valve, then piston drive valve to open or close water pump. This piston valve has followed functions such as balance control action, avoiding refluence, zero flow open and close, accidental power stop for water hammer and son on. Application of this piston valve had proved saving energy to 3%.