Effects of air jet duration and timing on the combustion characteristics of high-pressure air jet controlled compression ignition combustion mode in a hybrid pneumatic engine. (1st November 2016)

• Record Type: Journal Article
• Authors: Long, Wuqiang; Meng, Xiangyu; Tian, Jiangping; Tian, Hua; Cui, Jingchen; Feng, Liyan
• Is Part Of: Energy conversion and management. Volume 127(2016)
• Page Start: 392
• Page End: 403
• Publication Date: 2016-11-01
• Subjects: Diesel premixture -- Hybrid pneumatic engine -- Jet controlled compression ignition -- High pressure air; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2016.09.028
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: A 3-D CFD model of the power cylinder in HPE was developed. High-pressure air JCCI combustion mode includes two-stage high-temperature reaction. The combustion phasing of the pre-mixture is controllable via the SOJ timing. There exists an optimum SOJ timing for obtaining the highest combustion efficiency and shortest burning duration. Abstract: The high-pressure air jet controlled compression ignition (JCCI) combustion mode was employed to control the premixed diesel compression ignition combustion phasing by using the compound thermodynamic cycle under all operating conditions, which is accomplished in a hybrid pneumatic engine (HPE). A three-dimensional computational fluid dynamics (CFD) numerical simulation coupled with reduced n -heptane chemical kinetics mechanism has been applied to investigate the effects of high-pressure air jet duration and the start of jet (SOJ) timing on the combustion characteristics in the power cylinder of HPE. By sweeping the high-pressure air jet durations from 6 to 14 °CA and SOJ timings from −12 °CA ATDC to the top dead center (TDC) under the air jet temperatures of 400 and 500 K, respectively, the low- and high-temperature reactions, combustion efficiency, as well as the combustion phasing and burning duration have been analyzed in detail. The results illustrated that a longer air jet duration results in a higher peak in the first-stage high-temperature reaction, and the short air jet duration of 6 °CA can lead to a higher combustion efficiency. The SOJ timing sweep results showed that there exists an optimum timing for obtaining the highest combustion efficiency and shortest burning duration.