The dual-port fuel injection system for fuel economy improvement in an automotive spark-ignition gasoline engine

Lee, Yonggyu,Oh, Seungmook,Kim, Changup,Lee, Junsun,Lee, Kanghun,Kim, Junghwan Elsevier 2018 Applied thermal engineering Vol.138 No.-

<P><B>Abstract</B></P> <P>The purpose of the present study was to investigate the performance of the dual-port injection (DPI) system in an automotive spark-ignition engine. The DPI system utilizes two port fuel injection (PFI) injectors per cylinder, i.e., one injector at each intake port. An original 4-cylinder PFI engine head was modified to accommodate total 8 PFI injectors. In the present study, three spray angles and two install configurations were investigated in the intake port visualization, steady-state part-load experiments, and cold-start experiment. The intake port spray visualization experiment showed that the wider fuel spray provided better fuel distribution, but also more wall wetting. The steady-state engine experiment at the several critical part-load conditions showed that the DPI system in combination with the open-valve-injection strategy achieved the most brake specific fuel consumption (BSFC) reduction of 4.6%. The average BSFC reduction of the 9-point experiment was 2.8%. The cold-start experiment also showed a fuel economy gain by the DPI system. In the cold-start experiment the wider spray angle exhibited higher total hydrocarbon emission likely due to the greater wall wetting observed in the intake port spray images.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Dual port-fuel injection (DPI) for a spark ignition engine. </LI> <LI> High-speed camera visualized the wider spray angle of the DPI system. </LI> <LI> The DPI improved fuel economy by 2.8%. </LI> <LI> The DPI reduced hydrocarbon in cold-start. </LI> </UL> </P>

합성가스이용 엔진발전 기술

오승묵(Seungmook Oh),김창업(Changup Kim),이용규(Yonggyu Lee),박현욱(Hyunwook Park),이준순(Junsoon Lee) 한국연소학회 2019 KOSCOSYMPOSIUM논문집 Vol.2019 No.11

Recently syngas from various resources is widely used for energy and power generation as gasification technologies are improved to a large extent. Syngas combustion in an internal combustion engine have normally many technical challenges with the reason that its heating value is too low to obtain stable combustion. Even though hydrogen is one of main component gases in syngas, another non-combustible or inert gas like CO2 and N2 which deteriorate flame propagation speed occupy a large volume in the gas. In this study engine performance and emission characteristics with syngas were investigated and evaluated for real applications. Successful operations in stoichiometric and lean region were made with high compression ratios and emissions were also reduced with optimized operating parameters.

Experimental investigation of the hydrogen-rich offgas spark ignition engine under the various compression ratios

Oh, Seungmook,Kim, Changup,Lee, Yonggyu,Yoon, Sungjun,Lee, Junsoon,Kim, Junghwan Elsevier 2019 Energy Conversion and Management Vol.201 No.-

<P><B>Abstract</B></P> <P>Hydrogen is gaining substantial attention from both public and industries for its promising characteristics as an alternative fuel for internal combustion engines. High flame speed, strong knock resistance, as well as zero carbon dioxide emission put hydrogen ahead of most other alternative fuels. The fast flame and low knock tendency are favorable traits for high compression ratio, which is a key enabler for high efficiency. In this study, engine experiments were conducted to investigate the combustion and emission characteristics of a high-compression ratio, single-cylinder, spark-ignition engine with hydrogen-rich gas mixture. The compression ratio was varied from 10:1 to 17:1 by modifying the piston bowl geometry. The engine load was adjusted through the air fuel ratio by changing the mass flow rate of the fuel gas while the intake throttle valve maintained at wide open position. The consequent excess air to fuel ratio was varied from 3.5 at the lightest to 1.0 at the highest load operation. Spark timing sweep was performed to determine the optimal timings at various load conditions. The highest compression ratio in the present study, 17.0, yielded the highest indicated thermal efficiency, which was 51% at medium load condition. High and low load operations exhibited lower thermal efficiencies, with the estimated excess air to fuel ratio approaching 1.0 and 3.5, respectively. The optimal spark timings of the high load conditions under high compression ratios were retarded to top-dead center or later to avoid backfire and pre-ignition. Results of efficiency loss analysis show that high-temperature combustion is the major contributor to efficiency reduction at high load conditions, whereas the gas exchange process and elongated burn duration were the largest contributors at low load conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effects of compression ratio on hydrogen-rich gas mixture was investigated. </LI> <LI> Highest efficiency at a compression ratio of 17:1 was 51% at medium load condition. </LI> <LI> High-temperature combustion is a major source of efficiency reduction at high load. </LI> </UL> </P>

과급에 의한 바이오디젤의 저온연소 운전영역 확장에 관한 연구

오승묵(Seungmook Oh),장재훈(Jaehoon Jang),이용규(Yonggyu Lee),이선엽(Sunyoup Lee) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

바이오디젤 연료는 그 안에 포함된 산소성분으로 인해 압축착화엔진에 사용했을 때 일반디젤 연료보다 더 적은 입자상 물질을 배출한다. 따라서 이 연료를 저온연소 기법에 적용하는 경우 보다 효과적으로 NOx-PM을 동시 저감할 수 있고 그로부터 저온연소 운전영역의 확장을 기대할 수 있다. 이번 연구에서는 일반디젤과 대두유 기반의 바이오디젤 연료를 이용하여 Dilution controlled regime에서의 저온연소 운전을 구현하고 성능 및 배기 특성을 조사하였다. 엔진 실험 결과로부터 바이오디젤 연료의 경우 디젤에 비해 약 14% 낮은 발열량에도 불구하고 높은 세탄가 및 함산소 성질로 인한 연소효율 증가로 동일 연료량 분사 시 이보다 더 낮은 약 10~12% 정도의 출력이 감소함을 볼 수 있었다. 배기 측면에서도 바이오디젤 내 산소원자가 입자상물질의 산화반응을 촉진하여 최대 90%의 smoke 저감이 가능하며 THC, CO 역시 감소함을 관찰하였다. 또한 엔진 과급 실험으로부터 과급을 사용하여 저온연소 및 바이오디젤 사용으로 인한 출력 저하를 개선할 수 있음을 확인하였으며 과급과 바이오디젤 연료의 동시적용을 통해 더 적은 EGR 가스 투입으로도 저온연소에 상응하는 PM-NOx 동시 저감이 가능함을 보여주었다. 이런결과는 결국 이와 같은 과급 및 바이오디젤 연료의 적절한 조합으로부터 엔진 출력 향상과 배기특성 개선이 동시에 달성할 수 있음을 의미하며 이로부터 운전영역의 확대가 가능함을 제시하였다. Due to its O content, biodiesel (BD) has benefits in lowering PM in CI engines. This ability can make the fuel considered as one of the best candidates for LTC operation since use of BD can extend the regime for simultaneous reduction of PM and NOx. Thus, in this study, LTC operation was realized with BD and diesel at 5~7% O2 fraction. Engine test results show that use of BD raised efficiency and reduced emissions such as PM, THC and CO while IMEP was decreased by 10~12% due to lower LHV of the fuel. Especially, smoke was suppressed by up to 90% since O atom in BD enhanced soot oxidation reaction. To compensate IMEP loss, turbocharging (TC) was then tested and the results show that not only was power output increased but also PM was reduced further. Moreover, TC in BD engine operation allowed a similar level of reduction in both NOx and PM at 11~12% O2 fraction, meaning that there is a potential to widen the operating range by the combination of TC and BD.

합성가스/디젤 혼소압축착화 엔진의 압축비에 따른 연소 및 배출가스 특성

이준순 ( Junsun Lee ),정탄 ( Chung Than ),이용규 ( Yonggyu Lee ),김창업 ( Changup Kim ),오승묵 ( Seungmook Oh ) 한국액체미립화학회 2018 한국액체미립화학회 학술강연회 논문집 Vol.2018 No.-

Syngas is widely produced by incomplete combustion of coal, water vapor, and air (oxygen) in a hightemperature/ high-pressure gasifier through a coal-gasification technology for power generation. In this study, a simulation syngas is used with diesel as fuel and mainly composed of H₂, CO, CO₂, and N₂. A modified single cylinder compression ignition (CI) engine is equipped with intake port syngas supply system and mechanical diesel direct injection system for dual fuel combustion. Combustion and emission characteristics of the engine were investigated by applying various syngas composition ratios and compression ratios. Diesel fuel injection timing was optimized to increase indicated thermal efficiency (ITE) at the engine speed 1,800 rpm and part load IMEP 2 to 5 bar. ITE of the engine increased with the H₂ concentration, compression ratio and engine load. With 45% of H₂ concentration, compression ratio 17.1 and IMEP 5 bar, ITE of 41.5% was achieved, which is equivalent to that of only diesel fuel operation.

바이오디젤을 이용한 저온연소 운전영역 확장에 관한 연구

이선엽(Sunyoup Lee),장재훈(Jaehoon Jang),이기형(Kihyung Lee),이용규(Yonggyu Lee),오승묵(Seungmook Oh) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

디젤 저온연소 운전 영역에서 흡기압이 엔진 성능에 주는 영향

이선엽(Sunyoup Lee),장재훈(Jae Hoon Chang),이용규(Yonggyu Lee),오승묵(Seungmook Oh) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

디젤 저온연소 기술은 엔진 연소실 내부의 화학반응이 질소산화물(NOx) 및 입자상물질(PM)의 발생이 동시에 억제되는 저온연소 영역에서 이루어지도록 하는 신개념의 연소 기술이다. 이 때 저온 연소는 대용량의 EGR을 공급하여 연소실 내 가스의 비열을 높이고 연소실 내 산소 농도를 조절하는 방법과 적당량의 EGR을 공급하는 대신 디젤 연료를 TDC근처에서 분사하는 late-injection 방법으로 달성할 수 있는데, 이번 연구에서는 대용량의 EGR을 공급함으로써 저온 산화반응을 활성화하는 방법을 사용하였다. 그리고 이를 통해 저온연소 운전영역에서 흡기압력의 변화가 엔진의 출력 및 배기성능에 주는 영향을 디젤 단기통 엔진을 이용하여 조사하였다. 단기 통엔진의 실험 결과를 살펴보면 저온연소 운전은 산소농도8% 이하에서 성공적으로 구현되었으며 그 결과 질소 산화물과 입자상물질이 동시에 저감됨을 확인하였다. 하지만 저온연소 운전은 일반 디젤 연소에 비해 엔진 효율이 감소하고 출력이 낮아짐을 볼 수 있었으며 연소 온도 저하로 인해 THC 및 CO 배출 역시 증가함을 알 수 있었다. 저온 연소 영역에서 흡기압력의 영향을 보면 흡기 압력이 높아짐에 따라 더 낮은 산소농도 조건에서 Smoke의 발생이 최대가 될 뿐만 아니라 연소효율이 역시 향상되어 THC 및 CO의 배출이 감소함을 알 수 있었으며, 질소산화물의 경우 저온연소 영역에서는 흡기압력에 관계없이 거의 발생하지 않음을 확인 할 수 있었다. 또한 흡기 압이 높아질수록 엔진 출력 및 효율이 향상됨을 볼 수 있었으며 이로부터 흡기 압력 제어를 통한 저온연소 운전 영역 확대 및 배기 성능 향상 가능성을 확인하였다.

고압축비 전기점화 엔진의 성능 및 효율 향상을 위한 앳킨슨 사이클 최적화

이준순(Junsun Lee),박현욱(Hyunwook Park),오승묵(Seungmook Oh),김창업(Changup Kim),이용규(Yonggyu Lee),강건용(Kernyong Kang) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11

수소농후가스를 연료로 하는 전기점화엔진에 관한 연구

이용규(Yonggyu Lee),이준순(Junsun Lee),정탄(Tahn Chung),김창업(Changup Kim),오승묵(Seungmook Oh) 한국가스학회 2018 한국가스학회 학술대회논문집 Vol.2018 No.11

고압축비 전기점화 엔진에서 저발열량 합성가스 연료의 연소 및 배기 특성

이준순(Junsun Lee),박현욱(Hyunwook Park),잠스랑 나랑후(Narankhuu Jamsran),오승묵(Seungmook Oh),김창업(Changup Kim),이용규(Yonggyu Lee),강건용(Kernyong Kang) 한국자동차공학회 2022 한국 자동차공학회논문집 Vol.30 No.4

Syngas with a high-octane number can be used as fuel for spark ignition engines with a high compression ratio to improve thermal efficiency. Furthermore, the use of syngas is advantageous in terms of lean combustion due to its low ignition energy, and improvement in thermal efficiency can be expected. The simulated syngas was composed of hydrogen(H₂), carbon monoxide(CO), and carbon dioxide(CO₂). In this study, the characteristics of combustion and exhaust emissions based on the composition of syngas and load conditions were investigated. The in-line, six-cylinder compression ignition engine, with a compression ratio of 17.1, was modified to become a single-cylinder spark ignition engine. The coefficient of the variation of indicated mean effective pressure(COV<SUB>IMEP</SUB>) was limited within 5 % at 1800 rpm for full and part load conditions. The maximum load was obtained under a stoichiometric air-fuel ratio(AFR) condition, while high efficiency could be achieved at the lean operating condition. The maximum load increased with a higher H₂ and CO composition of syngas. Moreover, the lean operating condition was expanded, and the highest efficiency operating condition was moved to a relatively leaner operating region. In the case of 15 % H₂, 15 % CO, and 70 % CO₂, stable engine operation was ensured under full and part load conditions with low calorific value syngas. However, the lean operation region was reduced, and there was a deterioration in the engine’s gross indicated thermal efficiency(ITE<SUB>g</SUB>).