서지주요정보
SI 엔진에서의 NOx 및 UHC 저감에 관한 연구 = A study on the reduction of NOx and UHC emission in SI engines
서명 / 저자 SI 엔진에서의 NOx 및 UHC 저감에 관한 연구 = A study on the reduction of NOx and UHC emission in SI engines / 김창기.
저자명 김창기 ; Kim, Chang-Gi
발행사항 [대전 : 한국과학기술원, 1999].
Online Access 원문보기 원문인쇄

소장정보

등록번호

8009610

소장위치/청구기호

학술문화관(문화관) 보존서고

DME 99005

휴대폰 전송

도서상태

이용가능

대출가능

반납예정일

초록정보

At the present time, natural gas engines and gasoline engines which are two kinds of typical SI engines have different inherent emission problems. The noxious components which must be reduced first of all in natural gas engines and gasoline engines are NOx and UHC, respectively. It has been well known that the major source of NOx is the combustion temperature and that of UHC is the piston ring crevice volume. The purpose of this study is to reduce NOx emission in a natural gas engine and UHC emission in a gasoline engine by reducing the influence of these major root cause. The method for reducing NOx emission in this study was the lean burn technology. Lean burn usually accompanies unstable combustion quality though it reduces NOx emission automatically by dropping the combustion temperature. Therefore, investigation was focused on the stability of lean burn. Experiments were performed with a 4-stroke, natural gas engine under the various air-fuel ratio conditions. In order to stabilize the lean operation, the effect of several parameters such as charge swirl flow, direction of the ground electrode and high energy ignition systems were investigated. Shadowgraph visualization tests with a single-shot optical engine provided additional information which can be utilized for discussion of combustion diagnostics interpretation. It was possible to secure a strengthened turbulence and stable flame kernel growth as a result of a swirl vane installation at the inlet port together with a favorable direction of the ground electrode. Some improvement was observed under lean operating conditions with a long spark duration ignition system. The flame jet ignition system displayed a prominent capability for extending the lean limit. In a gasoline engine, influence of the inter-ring crevice volume on UHC emission was experimentally and numerically investigated. In the experiments, the inter-ring mixture was extracted to the crankcase during the late period of expansion and the early period of exhaust stroke through the engraved grooves on the lower part of cylinder wall. Extraction of the mixture resulted in significant reductions of UHC emission in proportion to the increments of the blowby flow rate, without any losses of efficiency and power. A relationship between the inter-ring mixture and UHC emission was established from the measured results. In addition, a physical model was constructed to predict the gas flows through the piston ring pack, and used to interpret the phenomena related to the results of experiments. Amount of the inter-ring mixture returning to the combustion chamber after exhaust valve open was calculated and converted to the corresponding UHC emission using the relationship between the inter-ring mixture and UHC emission in the experiments. Calculated level of UHC emission caused by the inter-ring crevice was 10-30% of the entire UHC emission over a range of speeds(1250-3500rpm) and loads (bmep 185-556kPa),which showed maximum at 2500rpm, bmep 432kPa, which corresponds to the condition most frequently operated by users.

서지기타정보

서지기타정보
청구기호 {DME 99005
형태사항 180 p. : 삽도 ; 26 cm
언어 한국어
일반주기 부록 : 피스톤 링 팩에서의 가스 유동에 관한 스뮬레이션
저자명의 영문표기 : Chang-Gi Kim
지도교수의 한글표기 : 최상민
지도교수의 영문표기 : Sang-Min Choi
수록 잡지명 : "Effect of Inter-Ring Crevice on Hydrocarbon Emission in an SI Engine.". Journal of Automobile Engineering. I.Mech.E.(Institution of Mechanical Engineers) (1999)
학위논문 학위논문(박사) - 한국과학기술원 : 기계공학과,
서지주기 참고문헌 수록
주제 질소산화물
미연탄화수소
희박연소
틈새체적
링간
NOx
UHC
Lean-burn
Crevice
Inter-Ring
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