• Proceedings of the KSME Conference
• /
• 2005.11a
• /
• pp.71.2-71.2
• /
• 2005

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.25 no.3
• /
• pp.157-163
• /
• 2016

Green vehicles include electric vehicles, natural gas vehicles, fuel cell vehicles (FCV), and vehicles running on fuel such as a biodiesel or an ethanol blend. An FCV is equipped with a cylinder valve installed in an ultra-high pressure vessel to control the hydrogen flow. For this purpose, an optimum design of the solenoid actuator is necessary to ensure reliability when driving an FCV. In this study, an electromagnetic field analysis for ensuring reliable operation of the solenoid actuator was conducted by using Maxwell V15. The electromagnetic field analysis was performed by magnetostatic technique, according to the distance between magnetic poles in order to predict the attraction force. Finally, the attraction force was validated through comparison between the Maxwell results and measurement results. From the results, the error of attraction force ranged from 4.53 % to 9.05 % at testing conditions.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.21 no.5
• /
• pp.719-726
• /
• 1997

The proportional pressure control valve having versatile functions and higher performance is an essential conponent in the open loop controlled rear wheel steering gear of the four wheel steering system in a passenger car. In this study, the authors suggest a new type of load pressure feedback mechanism which can make it easy to change the range of controlled pressure without changing the capacity of solenoid. The concept of suggested mechanism, composed of the pressure chamber with throttles in series, was described. The mathematical model was derived from the rear wheel steering gear consisting of a valve and a cylinder for the purpose of analyzing the valve characteristics. And the programme for computing the characteristic of the valve was developed. Experiments were performed to confirm the performance of the valve and computations were carried out to ascertain the usefulness of the developed programme. The results from computations fairly coincide with those from experiments. And the results from experiments and computations show that the performance of new valve was as good as that of the already developed one and the new valve has advantages such as the easiness of changing the range of controlled pressure and the decrease of power loss at neutral position without the decline of performance.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.10 no.5
• /
• pp.53-59
• /
• 2001

A screw driver is widely used in assembling machine parts or electronic products such as the printed circuit board with a housing. As the parts to be assembled becomes small and precise, the higher precision of the controlling screw driver torque is required. However, because the operator controls the fastening torque based on experience, it must be inexact and the setting procedure will be time consuming job. Thus the screw driver which can exactly control the fastening torque is developed utilizing a bellows in this paper. The bellows is expanded by the inner air pressure and contracted by the spring operation. The bellows type driver is composed of a clutch mechanism with two solenoid valves and a pressure sensor. Those valves are controlled using the detected bellows pressure by the sensor. When the pressure reaches the setting value, the exit solenoid valve is opened to release the air pressure from the bellows so as not to deliver further torque. Through a series of experiments, the performance is examined and verified.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.6
• /
• pp.1282-1289
• /
• 1988

It has recently shown that a solenoid valve can be utilized in a hydraulic position-control system by discontinuous control methods. The objective of this study is to investigate the effects of solenoid valves on the response characteristics of a hydraulic position-control system by applying two kinds of discontinuous control methods i.e., Simple On-Off(SOF) and Pulsating On-Off(POF) controls. Three types of solenoid valves i.e., low-frequency, closed-center type(LF/C), low-frequency, tandem-center type(LF/T) were used in this study. Effects of loading conditions and control parameters on the response characteristics were experimentally examined and compared each other. Pressure transients within the actuator were also studied.

• Journal of Drive and Control
• /
• v.9 no.4
• /
• pp.14-18
• /
• 2012

Two kinds of piezoelectric actuator are applied to the valve for controlling the direction, the flow and the pressure of the fluid. One is a stack type piezoelectric actuator which has very fast response characteristics but very tiny displacement. The other is a bender type piezoelectric actuator which has also fast response characteristics but lower than the stack type one, and has longer displacement than the stack type one. So, the bender type piezoelectric actuator has advantage to apply to the valve for controlling a large amount of flow and fast on-off operating. In this study, the bender type piezoelectric pneumatic valve for color sorter is designed and fabricated. The new type high speed piezo valve with the both side supporting mechanism for high operating frequency and high reliability is discussed for separating the foreign body from the grains. Finally, the performance characteristics of a fabricated valve are analyzed and the frequency characteristics are also discussed for substituting the conventional type solenoid actuator.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.8
• /
• pp.122-130
• /
• 1995

To reduce the shock in shifting, the clutches and the brakes in automatic transmission have to be connected smoothly and disconnected rapidly. It is PCSV(Pressure Control Solenoid Valve) that paly this role of automatic transmission. In this paper, there were two steps in the analysis of the PCSV. The first step was modeling the elctromagnet by the permeance method. The second step was modeling the hydraulic circuit by the pressure differential equa- tion. In addition to this modeling, a experiment was performed and the commercial package program was used in order to justify modeling. The result of modeling coincide with the result of experiment and commercial package program. As a result, this modeling is usable in analysis of dynamic characteristics of the PCSV.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.8 s.173
• /
• pp.64-70
• /
• 2005

The development of an accurate and energy saving pneumatic regulator that may be applied to a variety of practical pressure control applications is described in this paper. A novel modified pulse width modulation(MPWM) valve pulsing algorithm allows the pneumatic regulator to become energy saying system. A comparison between the system response of conventional PWM algorithm and that of the modified PWM(MPWM) algorithm shows that control performance is almost the same, but energy saving is greatly improved by adopting this new MPWM algorithm. The effectiveness of the proposed control algorithm are demonstrated through experiments with various reference trajectories.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.2
• /
• pp.81-91
• /
• 2000

Dynamic models of line regulator valve(LRV) and ratio control valve (RCV) are obtained for an electronic controlled CVT. LRV and RCV are operated by variable force solenoid(VFS). Considering the CVT shift dynamics, oil pump's efficiency and saturation characteristics of VFS, simulations are performed and compared with test results. Simulation results are in good agreement with the experiments, which shows the validity of the dynamic models of LRV and RCV obtained. In addition, the effects of the orifice size in the exhaust port of RCV are investigated. Simulation results show that as the orifice size decreases, the residual pressure in the primary actuator increases which insures the large torque transmission capacity, meanwhile the duration time for the downshift increases.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.88.6-88
• /
• 2002

In this study, the pneumatic servo valve was developed, and the study results could be summarized as follows; 1. A servo solenoid was designed, and its electromagnetic field was interpreted and the system's transient response was identified by using a commercial analysis program. 2. A program for analysis the flow in the spool was developed, and a study was conducted on the flow rate of the nozzle depending upon the pressure ratio between the upstream pressure and the downstream pressure, when the valve is fully opened in the spool and the flow force depending upon a displacement of the spool in the valve. 3. A PWM analog controller was designed and manufactured in...