• Journal of the korean Society of Automotive Engineers
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• v.10 no.4
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• pp.66-74
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• 1988

The ignition quality of ignition system is influenced by spark energy, discharge pattern of spark energy and spark duration. In this paper, the characteristics of multiple spark ignition system have been investigated for various number of spark and spark interval. The results, which were compared with those obtained with a standard single spark ignition, show that engine output is increased, and lean misfire limit is extended with the multiple spark ignition system. The most effective number of spark at the most effective spark interval that are determined by engine performance test, were 6 times spark at 0.02ms spark interval. For the above condition of spark, engine torque was increased about 20% comparing with conventional ignition system and lean misfire limit was extended to air-fuel ratio 22.5:1. This study researched the rate of heat release and quantity of heat release influenced by a condition of spark on the mass burned in order to investigate the relationship between the rate of mass burned and number of spark times.

• Journal of the korean Society of Automotive Engineers
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• v.11 no.5
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• pp.55-64
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• 1989

The effect of discharge have been investigated for condition of spark in a multiple spark ignition engine, as the spark duration, capacitive and inductive discharge energy were calculated for condition of spark by ignition wave and energy formula. The useful portion of spark discharge is divided into capacitance portion and inductance portion. It was found that capacitive discharge energy and spark duration were increased according to increasing number of spark, and inductive discharge energy was increased according to increasing spark interval. Therefore engine torque was increase and lean misfire limit was extended comparing with the standard ignition system. It found that spark energy was discharged within ignition delay period availability acted on the formation and growth of flame kernel, and total spark energy was increased according to increasing number of spark times, but discharged spark energy after ignition delay became unavailable energy. And the capacitive discharge energy has the dominant effect for stoichiomeric or not very rich air-fuel mixture but inductive discharge energy has the dominant effect for lean air-fuel mixture.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.120-125
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• 1993

The surface roughness of workpiece is reduced during spark-out. The reduction of roughness is a benefit of spark-out, but spark-out lowers productivity. The characteristics of spark-out are different to those of plunge grinding to which feed is applied. This difference is due to overlapping cutting during spark-out. Effect of spark-out is in proportion to volume of grain wear. This phenomenon is due to different overlapping area. Dressing interval can be enlarged by spark-out, when volume of grain wear is large. In this study, the characteristic of spark-out was studied by spark-out obserbation in various grinding conditions. For this purpose thrust force, spark-out time and surface roughness of workpiece were experimentally investigated in various grinding conditions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.1
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• pp.36-48
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• 1997

In order to establish the ignition system for lean burn, the influence of the number of spark plug, spark times and spark intervals on discharge pattern of spark energy on ignitability and combustion characteristics were evaluated. It showed that, ignitability remarkably increased with the case of multiple spark ignition system than with the case of single spark and the lean limit extended fuel/air equivalence ratio by 0.1, the increase of magnitude and lasting time of capacity component and inductance component was multi spark discharge in a row.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.2
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• pp.223-231
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• 1997

A variety of approaches have been investigated for the application of spark-ignition engine knock control. The control method implemented, here as "Fuzzy Control", has the advantage of not requiring the knowledge of a mathematical model of the controlled object and is more robust and flexible than conventional approaches. Knock control in this study is performed using vibration signal which is measured with accelerometer attached to the cylinder block of a 1498cc four-cylinder spark-ignition engine. The experimental results obtained with this method are compared with those obtained with a knock interval controller and with those of a conventional controller. Those results illustrate better performance in torque than knock interval controller and conventional controller.ontroller.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.1
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• pp.22-31
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• 1993

Spark-ignition engine knock is affected by engine operating conditions such as engine speed, spark timing and intake air temperature. In this study the effect of intake air temperature on knock characteristics was studied experimentally using a 4-cylinder carburetor spark-ignition engine. The cylinder pressure data at 2000rpm were taken for intake air temperature range of $30^{\circ}C$ to $80^{\circ}C$ with $10^{\circ}C$ interval. And 80 consecutive cycles were taken at each experimental condition. As the same spark timing, as the intake air temperature increased by $50^{\circ}C$, the mean knock intensity increased about 20kPa. This effect corresponds to that of spark timing advance of 3 crank angle degrees.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.11
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• pp.3676-3685
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• 1996

Enhancement of the ignitability was necessary to realize the lean burn engine. The characteristics of multiple-spark capacitor discharge igniter(MSCDI) usefulness of which for lean burn was examined in constant volume combustion chamber and evaluated in spark ignition engine. Noise of MSCDI for engine was restricted by adoption of low voltage control system. It was found that the adaptability for high engine speed was remarkable. Lean limit in engine with MSCDI was extended 10% than conventional coil ignition system. Also maximum brake thermal efficiency was almost enhanced 1%.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.12
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• pp.1647-1655
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• 1997

The cyclic variations can be characterized by the variations in different type of parameters. These parameters may be grouped into four main categories: pressure-related parameters, combustion-related parameters, flame front-related parameters, and exhaust gas-related parameters. One of the resultant effects of the cycle-by-cycle variation in the combustion process, which is the most important with regard to the engine performance characteristics, is the cycle-by-cycle variation in IMEP. This paper uses the repetitive discharge igniter, which can change the ignition energy easily, to study on idle stability in a spark ignition engine. From this device, the 6 number of spark and 0.20 ms spark interval, it is very available for the idle stability.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2761-2781
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• 2018

With the continuous growth of data size and the use of compression technology, data reduction has great research value and practical significance. Aiming at the shortcomings of the existing semantic compression algorithm, this paper is based on the analysis of ItCompress algorithm, and designs a method of bidirectional order selection based on interval partitioning, which named An Optimized Iterative Semantic Compression Algorithm (Optimized ItCompress Algorithm). In order to further improve the speed of the algorithm, we propose a parallel optimization iterative semantic compression algorithm using GPU (POICAG) and an optimized iterative semantic compression algorithm using Spark (DOICAS). A lot of valid experiments are carried out on four kinds of datasets, which fully verified the efficiency of the proposed algorithm.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.3
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• pp.60-65
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• 1988

The ignition characteristics of repetitive electric sparks into a quiescent acetylene-air premixture and LPG-argon-air premixture was investigated by using a home-made Repetitive-Spark-Generator(RSG) to elucidate the effect of fuel burning velocity to ignition ability of RSG. Results show that the optimum spark delay time interval is strongly related with fuel burning velocity, or implicitly with characteristic reaction time scale of each fuel.