Impact of post-injection strategy on the physicochemical properties and reactivity of diesel in-cylinder soot |
| |
Authors: | Chenyang Fan Chonglin Song Gang Lv Jiangjun Wei Xuyang Zhang Yuehan Qiao Ye Liu |
| |
Affiliation: | State Key Laboratory of Engines, Tianjin University, Tianjin 300072, China |
| |
Abstract: | Post injection has significant benefit in the reduction of diesel soot emissions. Therefore, there is a need to understand the effect of post-injection strategy on soot physicochemical properties and reactivity because they play an important role in soot oxidation process that governs the final soot emissions. This work focuses on the impact of post injection on the physicochemical properties and reactivity of diesel in-cylinder soot using a main plus post injection (M*P) and a single injection (M) strategy. The soot was sampled by a developed total cylinder sampling system, and the dividing points of soot formation-dominant and oxidation-dominant phases were used for studying the impacts of post injection on the characteristics of in-cylinder soot. The physicochemical properties of the soot samples, including primary particle size, nanostructure, carbon chemical state and surface functional groups, were characterized. The soot reactivity was evaluated in terms of peak temperature, burnout temperature and apparent activation energy. In the oxidation-dominant phase, the M*P soot initially possesses smaller primary particle size, shorter fringe length, larger tortuosity, lower sp2/sp3 hybridization ratio of carbon atoms and higher content of aliphatic C![/>H groups than the M soot. The beneficial influence of physicochemical properties on soot reactivity when using post injection is validated by the thermogravimetric data, which shows that the M*P soot is more reactive than the M soot at the onset of the oxidation-dominant phase. In the M*P case, the soot generated from the main-injection combustion has lower reactivity than the soot from the post-injection combustion after they experience the soot formation-dominant phase. The results indicate that the use of post injection leads to in-cylinder soot with physicochemical properties that favor reactivity. The enhancement of reactivity means that the soot will be more readily oxidized in the subsequent combustion process, and consequently contributes to a reduction in final soot emissions.</td>
</tr>
<tr>
<td align=](https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd) | |
Keywords: | Diesel engine Post injection In-cylinder soot Physicochemical property Reactivity |
本文献已被 ScienceDirect 等数据库收录! |
|