터보과급 가솔린 기관의 노크한계 압축비에 관한 중간냉각 효과

金 進 慶一大學校 1990 論文集 Vol.6 No.1

Thubocharger drives turbin using exhaust gas as a power source, it compresses inlet air by driving on line compressor and so it charges air mass flow into combustion chamber. Therefore, turbocharging can achieve the same power more large engine since it charges mixture gas into combustion chamber. Also turbocharging is reasonable for it uses exhaust gas energe which is to be lost usually in combustion. Mentioned before, it can grossify the engine power without increases of displacement and engine speed. Moreover, it is very useful engines in view of developing high powering, economizing fuel and reducting engine size in well balanced way. However turbocharged gasoline engine is easy to making knock as the gas pressure & temperature in combustion chamber is hightening and it causes also thermal changes in engine structure for thermal stress from combustion gas of high temperature & high pressure. Also, turbocharged gasoline engine has complex relation with charge pressure ratio, air fuel ratio, spark advance and response to acceration character, matching on turbocharged gasoline engine with intercooer. Therefore, we must secure fundemental source about above relations for bettwe design of turbocharged gasoline engine. By the way, first problems in turbocharged gasoline engines different from disel engine is knock occurence and it makes charge limit. Knock occurence can be constrainted by retarding spark time. Further studies are needed about knock limit comression ratio, knock limit spark advance and intercooling effect to knock limit compression ratio for determining compression ratio in design of turbocharged gasoline engines becasue knock limit changes according to change of compression ratio. This study purposes fundamental design data secure determining compression ratio of turbocharged gasoline engine. We determined knock limit compression ratio to charge pressure change. This result data adapted in relation equation about knock limit compression ratio & knock limit charge pressure ratio based on autoignition theory. Adapting result can be classified for without & with intercooler. Case of intercooling gains charge pressure rise as well as maximum engine power for intercooling reduces knocking and it makes engine drive limit farther. Knock limit compression ratio to charge pressure ratio is also glossified in case of intercooling. Comsequently, it is clear in this study that if turbocharged gasolin engine is intercooled, density ratio augmentation & knock limit compression ratio magnification of turbocharged gasoline engine will increase the power of engine. Therefore, we can suggest fundamental design sources for determing compression ratio of turbocharged gasoline engine.

터보과급 가솔린 기관의 중간냉각 효과

金 進 慶一大學校 1999 論文集 Vol.16 No.5

Turbocharger drives turbin using exhaust gas as a power source, it compresses inlet air by driving one line compressor and so it charges air mass flow combustion chamber. However turbocharged gasoline engine is easy to making knok as the gas pressure & temperature in combustion chamber is hightening and it causes also thermal changes in engine structure for thermal stress from combustion gas of high temperature & high pressure. First problems in turbocharged gasoline engines different from disel engine is knock occurrence and it makes charge limit. Knock occurrence can be constrainted by retarding spark time. Further studies are needed about knock limit compression ratio, knock limit spark advance and intercooling effect to knock limit compression ratio for determining compression ratio in design of turbocharged gasoline engines because knock limit changes according to change of compression ratio. This study purpose fundamental design data secure determining compression ratioof turbocharged gasoline engine. We determined knock limit compression ratio to charge pressure change. This result data adapted in relation equation about knock limit compression ratio & knock limit charge pressure ratio based on autoignition theory. Adapting result can be classified for without & with intercooler. Case of intercooling gains charge pressure rise as well as maximum engine power for intercooling reduces knocking and it akes engine drive limit farther. Knock limit compression ratio to charge pressure ratio is also glossified in case of intercooling. Consequently, it is clear in this study that if turbocharged gasolin engine is intercooled, density ratio augmentation & knock limit compression ratio magnification of turbocharged gasoline engine will increase the power of engine. Therefore, we can suggest fundamental design sources for detenning compression ratio of turbocharged gasoline engine.

터보과급 가솔린 기관의 성능특성에 관한 실험적 해석

金 進 慶一大學校 1999 論文集 Vol.16 No.2

Turbocharging an engine improves the engine performance without increasing a piston displacement or an engine speed. Since the turbocharging reduces both the engine size and the weight by improving a specific output, it results in a minimal specific fuel consumption. Therefore, passenger cars often employ the turbocharged gasoline engine recently. On the other hand, this approach causes a high thermal stress and a high temperature, and thus the turbocharged engine may experience and irregular flaming within the combustion chamber or an irrevocable deformation of the engine structure. To analyze this complex phenomena, we need to consider the variation of a matching between the compressor and the turbine, an air-fuel ratio, a supercharge pressure ratio, and a spark timing, etc. This paper studies the performance of the turbocharged engine, and experimental data is provided for further development of a high-performance turbocharged gasoline engine.

二次燃燒效果의 簡易評價法에 關한 硏究

金 進 慶北工業專門大學 1977 論文集 Vol.14 No.-

As one of countermeasures for preventing automotive air pollution, there is system, witch is called post-combustion, that the products of incomplete combustion in exhaust gas are burned by the secondary air while the exhaust gas is kept at high temperature. In this system, evaluating post-combustion effects, it must be taken care that the products of incomplete combustion, even if post-combustion is done or not, will be diluted by secondary air. Thereupon by setting up the combustion equation after consideration of the dilution by secondary air, the relation between the secondary-air quantity and the diluted exhaust-gas composition was calculated and the results were chared.

PIV의 문제점 및 임펠러 내부의 유동측정

金 進,金丙文 慶一大學校 1999 論文集 Vol.16 No.5

After visualizing by using halogen lamp, CCD Video camera about flow field of standard impeller and tandem impeller, the velocity calculation was conducted through the PIV(Particle Image velocimetry). For the improvement of degree of the calculation, the tracer, images picture interval and the characteristics of CCD video camera were analyed and sus-calculation was conducted. In the case of correlation method of density pattern, many space-frequency including in the correlation matrix is good and in the case of the flow field of large scale if the frame-interval of two images using in the correlation calculation is not error vector, one knows that the large vector in variation is increasing. Also the effect of noise is easier as the frequency-intensity including in image is smaller, and the brightness of PIV was largely affected as the frequency-intensity is larger. It is possible to quantitatively analyze the flow field in a rotating impeller by PIV system.