• Tribology and Lubricants
• /
• v.13 no.1
• /
• pp.62-69
• /
• 1997

Rapid increase of refrigeration and air-conditioning systems 9r & a systems) in modern industries brings attention to the urgency of research & development as a core technology in the area. And it is required to the compatibility problem of r & a systems to alternative refrigerant for the protection of environment. The, it is requested to study the lubrication characteristics of refrigerant compressor which is the core technology in the r & a systems. The study of lubrication characteristics in the critical sliding component is essential for the design of refrigerant compressor. Therefore, theoretical investigation of the lubrication characteristics of rotary compressor for r & a systems is studied. The newton-Raphson method is used for the EHL analysis between vane and rolling piston in the rotary compressor. The results show that the rotational speed of a shaft and the discharge pressure influence significantly the friction force between vane and rolling piston. This results give important basic data for the further lubrication analysis and design of a rotary compressor.

• Transactions of The Korea Fluid Power Systems Society
• /
• v.7 no.1
• /
• pp.1-5
• /
• 2010

This paper presents the experimental results of the radial piston type oil pump with new mechanism for a metal diaphragm hydrogen compressor. Generally, metal diaphragm type hydrogen compressor systems are operated by oil hydraulic power. In this system an oil compensating pump has been demanded to compensate for a leakage oil head chamber. The metal diaphragm type hydrogen compressor consists of an oil compensating pump, commonly used hydraulic piston pump and driven by main crank shaft. The radial piston type oil compensating pump with new rolling contacted piston mechanism is developed and experimented. The developed piston element of the radial piston pump consists of piston, steel ball, return spring, two check valves, eccentric cam and ball racer. In this study, designed 4 type pistons as and orifice hole. Operating characteristics and pressure ripple characteristics are tested under no load to 60bar loaded with every 20bar increasing step and pressure ripple and flow rate are experimentally investigated.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.13 no.5
• /
• pp.82-89
• /
• 2005

This study was performed to investigate the behavior and spatial distribution of fuel mixtures with different wall angle and diameter of piston cavity in a DI gasoline engine. The spatial distribution of fuel mixtures after impingement of the spray against a piston cavity is one of the most important. factors for the stratification of fuel mixture. Thus, it is informative to understand in detail the behavior and spatial distribution of fuel mixtures after impingement in the cavity. Two dimensional spray fluorescence images of liquid and vapor phase were acquired to analyze the behavior and distribution of fuel mixtures inside cylinder by exciplex fluorescence method. The exciplex system of fluorobenzene/DEMA in non-fluorescing base fuel of hexane was employed. Cavity wall angle was defined as an exterior angle of piston cavity. Wall angles of the piston cavity were set to 30, 60 and 90 degrees, respectively. The spray impinges on the cavity and diffuses along the cavity wall by its momentum. In the case of 30 degrees, the rolling-up moved from the impinging location to the round and fuel-rich mixture distributed at periphery of cylinder. In the case of 60 and 90 degrees, the rolling-up recircurated in the cavity and fuel mixtures concentrated at center region. High concentrated fuel vapor phase was observed in the cavity with 90 degrees. From. present study, it was found that the desirable cavity wall angle with cavity diameter for stratification in a Dl gasoline engine was demonstrated.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2007.11a
• /
• pp.418-421
• /
• 2007

For Shock obsorber piston led is launched to the market through luring, milling, grooving, rolling, inspection and finally packing processes, To this time around 11 items, that is, out diameter and length etc..for the piston lod are inspected strictly as a total inspection. Piston Lod is being produced 30,000 a day and its excessively repeating inspection is getting induce repetition strain injury and reduce production rate as fatigue accumulation of worker increase inspection errors. Therefore, for the inspection process is severely needed a progressive improvement through the automation. In this study, we consider automation method of piston led inspection process and suggest an efficient automation strategy as improving the various problems in present manual inspection way.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.24 no.5
• /
• pp.385-390
• /
• 2012

This paper discusses the applicability of a compact rolling piston refrigeration compressor to portable refrigerators. The capacity of this compressor is 1 cc. Using a 12 V BLDC motor, the compressor is driven from 2500 rpm to 6000 rpm. The height of the compression module and motor is approximately 56 mm, and their weight is approximately 374 g. We confirmed the effective operation of the compressor components by evaluating their compression and cooling performance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.12
• /
• pp.1245-1254
• /
• 2001

For a R410A-rolling piston type rotary compressor model which was modified by reducing the cylinder height and shaft eccentricity from R22-compressor version, numerical simulation has been carried out and simulation results have been found to be compared fairly well with those of measurements. EER of this first version of R410A compressor was 4.8% lower than that of R22 compressor. To improve the performance of the R410A compressor model, parametric study on the design parameters related to the discharge port system has been performed by using the numerical simulation program, and optimum conditions for the highest EER have been obtained with the aid of Taguchi method. With the optimized discharge port configuration, EER has been improved by 1.7%.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.6
• /
• pp.205-213
• /
• 2003

This paper is concerned with a roiling piston type rotary compressor for air conditioning use. Vibration of the compressor is analyzed numerically and experimentally. Multibody dynamic analysis methods to predict the vibration is given. The compressor is modeled as a system composed of bodies, joints, and force elements. Experimental results are also shown to be compared with simulation results. A sensitivity study using different variables that affect the compressor vibration is also carried out. It is found that the mass of weight balancer plays an important role in acceleration.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.04a
• /
• pp.435-439
• /
• 2002

In the pneumatic system, pneumatic cylinder is wildly used to factory automation. In general, Pneumatic cylinder problems are occured with colliding to stroke end part at which piston collide to end-cap, head cap and tube when piston is loading. This appearances have a short life of cylinder and is due to system destruction. This study examines the dynamic characteristics of pneumatic cushioning cylinder and cushion sleeve design. At head part cushion chamber for the vertical experimental, The decisions of cushioning effect and the results of the experimental research are obtained to the followings: i) The cushioning effects could acqure to the reserch, if the compressible energy is more than kinetic ones. ii) The collision of piston and head cover could acqure to the research, if the kinetic energy is more than compressible iii) If the load increase to the rolling car, the cushion region pressures would increase and the dynamic force.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2001.11a
• /
• pp.230-236
• /
• 2001

We developed a built-in sensor bearing to measure the rotor motion of a rolling piston type compressor for the air conditioner. Because of needs for the high efficiency and long life span of compressor, and the usage of alternative refrigerants, the operating condition of the compressor becomes more severe. The accurate measurement of the rotor motion of the compressor can contribute greatly to the design and analysis of the hydrodynamic bearing. However, it is difficult to measure accurately the shaft behavior of small compressor because of the small space for the sensor mount, high temperature and pressure of compressor, oil mixed with refrigerant, and electromagnetic noise of the motor. To overcome these difficulties, we develop the cylindrical capacitive sensor that is built in the hydrodynamic bearing and calibrate the built-in sensor bearing indirectly through measuring the oil relative permittivity. We measured the rotor motion as well as suction and discharge pressures in various conditions. The several experimental results show that the developed built-in sensor bearing can measure the rotor motion not only in steady state but also in transient state.

• The KSFM Journal of Fluid Machinery
• /
• v.18 no.3
• /
• pp.12-19
• /
• 2015

As a means of improving cycle performance of a R410A air-conditioning system, a combined structure of compressor and expander was introduced. A vane rotary type expander was designed to share a common shaft with twin type rolling piston rotary compressor in a housing. Numerical simulation on the performance of the combined compressor and expander was carried out. At ARI condition, the volumetric and total efficiencies of the designed vane expander were 69.37% and 30.23%, respectively. With the application of this expander, the compressor input was reduced by 3.91%, and the cooling capacity was increased by 3.98%. As a result, COP of the air-conditioning system was improved by 8.2%. As the pressure difference between the condenser and the evaporator becomes large, COP improvement increases unless the mass flow rate in the expander exceeds that in the compressor.