scholarly journals Optimization of Pilot Injection Pattern and Its Effect on Diesel Combustion with High-Pressure Injection.

1994 ◽  
Vol 37 (4) ◽  
pp. 966-973 ◽  
Author(s):  
Kiyomi Nakakita ◽  
Teruaki Kondoh ◽  
Katsuyuki Ohsawa ◽  
Takeshi Takahashi ◽  
Satoshi Watanabe
1993 ◽  
Vol 59 (559) ◽  
pp. 892-898 ◽  
Author(s):  
Kiyomi Nakakita ◽  
Teruaki Kondoh ◽  
Katsuyuki Ohsaw ◽  
Takeshi Takahashi ◽  
Satoshi Watanabe

2019 ◽  
Vol 9 (4) ◽  
pp. 647 ◽  
Author(s):  
Seamoon Yang ◽  
Changhee Lee

In this paper, the effect of high-pressure injection pressure on particulate matter (PM) and nitrogen oxide (NOx) emissions is discussed. Many studies have been conducted by active researchers on high-pressure engines; however, the problem of reducing PM and NOx emissions is still not solved. Therefore, in the existing diesel (compression ignition) engines, the common rail high-pressure injection system has limitations in reducing PM and NOx emissions. Accordingly, to solve the exhaust gas emission problem of a compression ignition engine, a compression ignition engine using an alternative fuel is discussed. This study was conducted to optimize the dimethyl ether (DME) engine system, which can satisfy the emission gas exhaust requirements that cannot be satisfied by the current common rail diesel compression ignition engine in terms of efficiency and exhaust gas using DME common rail compression ignition engine. Based on the results of this study on diesel and DME engines under common rail conditions, the changes in engine performance and emission characteristics of exhaust gases with respect to the injection pressure and injection rate were examined. The emission characteristics of NOx, hydrocarbons, and carbon monoxide (CO) emissions were affected by the injection pressure of pilot injection. Under these conditions, the exhaust gas characteristics were optimized when the pilot injection period and needle lift were varied.


2021 ◽  
Author(s):  
Long Liu ◽  
Tianyang Dai ◽  
Qian Xiong ◽  
Yuehua Qian ◽  
Bo Liu

Abstract With increasingly stringent emissions limitation of greenhouse gas and atmospheric pollutants for ship, the direct injection of natural gas on the cylinder head with high-pressure injection is an effective method to make a high power output and decrease harmful gas emissions in marine natural gas dual fuel engines. However, the effects on mixing characteristics of high-pressure natural gas underexpanded jet have not been fully understood. Especially, the injection pressure is up to 30 MPa with large injection quantity and critical surrounding gas conditions for the low-speed two-stroke marine engine. Therefore, this research is focused on the flow and mixing process of the natural gas jet with high-pressure injection under the in-cylinder conditions of low-speed two-stroke marine engine. The gas jet penetration, the distribution of velocity and density, the equivalence ratio and air entrainment have been analyzed under different nozzle hole diameters by numerical simulation. The effects of surrounding gas conditions including pressure, temperature and swirl ratio on air entrainment and equivalence ratio distribution were studied in detail. From the numerical simulation, it is found that the mixing characteristics of natural gas jet can be improved under in-cylinder conditions of higher ambient temperature and swirl ratio, which is relevant to the low-speed two-stroke marine engine.


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