A predictive Livengood–Wu correlation for two-stage ignition. (October 2016)

• Record Type: Journal Article
• Authors: Pan, Jiaying; Zhao, Peng; Law, Chung K; Wei, Haiqiao
• Is Part Of: International journal of engine research. Volume 17:Number 8(2016)
• Page Start: 825
• Page End: 835
• Publication Date: 2016-10
• Subjects: Livengood–Wu integral -- auto-ignition -- two-stage ignition -- negative temperature coefficient -- cool flame -- engine knock; Engines -- Periodicals; 629.25
• DOI: 10.1177/1468087415619516
• Languages: English
• ISSNs: 1468-0874

Abstract

The Livengood–Wu correlation has been widely used to predict the state of auto-ignition in internal combustion engines, although its application to two-stage ignition processes remains unresolved. In this study, the original Livengood–Wu integral is extended to such two-stage ignition process and applied to simulations of typical operations within homogeneous charge compression ignition engines. Specifically, based on recent understanding of the global and detailed kinetics of low-temperature chemistry leading to ignition, simplified Arrhenius-based global reaction expressions were developed for both stages of constant-state auto-ignition. It is shown that the original Livengood–Wu integral works well for the first-stage ignition delay, as demonstrated in previous studies. Furthermore, by also accurately describing the cool flame temperature and pressure increment at the end of the first-stage ignition, the second-stage ignition delay can in addition be coupled with the first-stage ignition and predicted satisfactorily with a second integral. This formulation is then applied to extensive homogeneous charge compression ignition engine operation conditions, showing satisfactory predictive capability.