• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.7
• /
• pp.181-186
• /
• 1999

The objective of present work is to investigate the performance characteristics of three-lobe Roots type supercharger for the applications of low-compression and high-expansion ration gasoline engine. A performance test was conducted to obtain the drive power, volumetric efficiency, adiabatic efficiency and the influence of performance factors of supercharger . In order to analyze the supercharging characteristics, the experiments are made on operating parameters such as the supercharger speed, pressure ration and inlet temperature on the supercharging performance of the Roots type supercharger . Based on experimental results, the drive power and flow rate of supercharger increased with supercharger speed.

• Journal of Advanced Marine Engineering and Technology
• /
• v.25 no.1
• /
• pp.115-123
• /
• 2001

This study describes the combustion characteristics under various condition of air excess ratio and ignition timing in a 2-valve gasoline optically accessible engine with swirl control valve(SCV). It adapted three different types of SCA(open ration 72.5%, 78%, 89%) to strengthen a swirl flow. Pressure data were acquired using pressure sensor to investigate the effect of swirl flow on combustion, and from these pressure data, IMEP(indicated mean effective pressure) and MFB(mass fraction burnt)were calculated to explain burn rate and flame speed. From acquired flame images, inspected the flame propagation direction, flame area, and flame centroid, Flame propagation direction was shown different tendency between with/without SCV, and flame area with SCV was faster and larger than that of conventional engine. Finally, the representative flame image at each crank angle were acquired by PDF method to verify flame growth process. It is found that strengthened swirl flow is more beneficial for faster and stable combustion.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.2
• /
• pp.349-357
• /
• 1990

Power transmission characteristics and speed ratio-torque load-axial force relationship for a metal V-belt CVT were investigated theoretically and experimentally. In the metal V-belt CVT drive, it was found that the power was transmitted by thrust force and that band tension should be greater than compression force between the metal blocks. The experimental results for the speed ratio-torque load-axial force relationship showed good agreement with those predicted using equations developed from theoretical considerations.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.9
• /
• pp.2181-2190
• /
• 1993

An electro-hydraulic controlled rig type CVT(Continuously Variable Transmission) system was developed and its performance tests were carried out for the optimal operation. A CVT map was suggested based on the speed ration-axial force-torque relationship which was derived from the metal belt CVT mechanics. Also, a real time control and operation software was developed for the electro-hydraulic CVT system. By using the software and the CVT map, the control system was designed for the CVT speed ratio control with various drive modes. The electro-hydraulic CVT system developed in this study showed that the optimal operation algorithm could be obtained for the best fuel economy or the maximum power mode.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.8
• /
• pp.132-142
• /
• 1999

In this paper, a new formula for primary and secondary thrust of metal belt CVT is proposed considering variation of band tension, block compression and active arc for each of the primary and secondary pulleys. For the secondary thrust, effective friction coefficient is introduced considering the effect of flange deflection. Nondimensional primary and secondary thrust of the metal belt CVT by the new formula agree well with the experimental results except for low torque range, $0\;<\;{\lambda}\;<\;0.2$ at speed ration i = 1.0. The new formula can be used in design of the primary and secondary thrusts control system for the metal belt CVT.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.8 no.4
• /
• pp.18-25
• /
• 2000

Ion current in an S.I engine cylinder is measured with the spark plug as a probe. The peak values are confirmed to show a fair correlation with local air-fuel ration and engine speed which implies that the ion current measured at the spark plug may provide a signal for the local mixture strength which is the key parameter in precise fuel control for future engines especially of gasoline direct-injected lean burn engines.

• Journal of the Korea Society of Computer and Information
• /
• v.12 no.2 s.46
• /
• pp.131-139
• /
• 2007

This paper proposed a multi-resolution algorithm. Its search point and complexity were compared with those of block match algorithm. Also the speed up comparison was made with the block match algorithm. The proposed multi-resolution NTSS-3 Level algorithm was compared again with its targets, TSS-3 Level algorithm and NTSS algorithm. The comparison results showed that the NTSS-3 Level algorithm was superior in search point and speed up. Accordingly, the proposed NTSS-3 Level algorithm was two to three times better in search point and two to four times better in complexity calculation than those of the compared object, the block match algorithm. In speed up, the proposed NTSS-3 Level algorithm was two times better. Accordingly, the proposed multi-resolution NTSS-3 Level algorithm showed PSNR ration portion excellency in search point and speed up.

• International Journal of Precision Engineering and Manufacturing
• /
• v.2 no.2
• /
• pp.57-64
• /
• 2001

In recent years, the concern of designing multi-stage gear drives ha increased with more application of them in high-speed and high-load. Until now, however, the researches on the design of gear drives have been focused on single gear pairs. Thus the design practice for multi-stage gear drives has been depended on experiences and expertise of designers and carried out commonly by trial and error. We propose an automation algorithm for the design of two-and three-strage cylindrical gear drives. The two types of dimensional design processes have been proposed to determine gear dimensions in a formal way. The first design process(Process I) uses to total volume of gears to determine gear ration , and uses K factor , unit load and aspect ration to determine gear dimensions, The second one(Process II) makes use of Niemann's formula and center distance to calculate gear ratio and gear dimensions. Process I and Process II employ material date from AGMA and ISO standards, respectively. The configuration design determines the positions of gears with minimizing the volume of gearbox by using a simulated annealing algorithm. The availability of the design algorithm is validated by the design examples to two-and three=stage gear drives.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1999.10a
• /
• pp.381-386
• /
• 1999

In machining with cutting tool inserts having complex chip groove shape, the flow, curl and breaking patterns of the chip are different than in flat-face type inserts. In the present work, an effort is made to understand the three basic phenomena occurring in a chip since its formation in machining with groove type and pattern type inserts. These are the initial chip flow, the subsequent development of up and side curl and the final chip breaking due to the development of torsional and banding stresses. In this paper, chip flow angle in a groove type and pattern type inserts. The expression for chip flow angle in groove type and pattern type insets is also verified experimentally using high speed filming techniques.

• Journal of Institute of Control, Robotics and Systems
• /
• v.11 no.10
• /
• pp.870-879
• /
• 2005

This paper presents that a transient response can be characterized by certain parameters which are correlated to characteristic polynomial coefficients. These are characteristic ratios and characteristic pulsatances by P. Naslin [4]. We have developed an approach to control directly the transient response. Firstly, speed of the response can be controlled by reconstruction form via multipliable characteristic pulsatances. Secondly, overshoot is controlled by reconstruction form via multipliable characteristic ratios. These formulas can be independently characterized by the system overshoot and the response time to a step input.