Advanced

Influence of Injection Timing on Exhaust Particulate Matter Emissions of Gasoline in HCCI and PPC

Shen, Mengqin LU ; Tuner, Martin LU ; Johansson, Bengt LU ; Tunestal, Per LU and Pagels, Joakim LU (2016) In SAE Technical Papers 2016-Octobeer.
Abstract

In order to reduce nitrogen oxides (NOx) and soot emissions while maintaining high thermal efficiency, more advanced combustion concepts have been developed over the years, such as Homogeneous Charge Compression Ignition (HCCI) and Partially Premixed Combustion (PPC), as possible combustion processes in commercial engines. Compared to HCCI, PPC has advantages of lower unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions; however, due to increased fuel stratifications, soot emissions can be a challenge when adding Exhaust-Gas Recirculation (EGR) gas. The current work presents particle size distribution measurements performed from HCCI-like combustion with very early (120 CAD BTDC) to PPC combustion with late injection timing (11... (More)

In order to reduce nitrogen oxides (NOx) and soot emissions while maintaining high thermal efficiency, more advanced combustion concepts have been developed over the years, such as Homogeneous Charge Compression Ignition (HCCI) and Partially Premixed Combustion (PPC), as possible combustion processes in commercial engines. Compared to HCCI, PPC has advantages of lower unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions; however, due to increased fuel stratifications, soot emissions can be a challenge when adding Exhaust-Gas Recirculation (EGR) gas. The current work presents particle size distribution measurements performed from HCCI-like combustion with very early (120 CAD BTDC) to PPC combustion with late injection timing (11 CAD BTDC) at two intake oxygen rates, 21% and 15% respectively. Particle size distributions were measured using a differential mobility spectrometer DMS500. Additionally, to get knowledge of the effect of injection timing on particle size distributions in PPC mode, measurements were performed in injection timing sweeps at engine speeds 800 rpm and 1600 rpm. Results show that, without EGR, throughout the injection timing from very early to late injection, a unimodal particle size distribution dominated by nucleation mode particles can be observed. Adding EGR, similar unimodal particle size distributions are obtained for early injection timings whereas bimodal size distributions appear for late injection timings when injecting goes into the bowl. The corresponding accumulation mode particle number rapidly increases and results in a high engine-out soot output. In PPC mode with high fuel stratification, a similar trend is found at engine speeds 800 rpm and 1600 rpm during injection timing sweeps. Retarding injection is generally found to reduce particle numbers in nucleation mode and increase numbers in accumulation mode, which leads to a higher soot mass output despite of a reduction in total particle numbers. It can be concluded that charge stratification and fuel impingement influence particle size distributions during injection timing variations.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
SAE Technical Papers
volume
2016-Octobeer
publisher
Society of Automotive Engineers
external identifiers
  • scopus:85019588075
ISSN
0148-7191
DOI
10.4271/2016-01-2300
language
English
LU publication?
yes
id
5333a2c0-5201-4464-8a27-3f69dfea3628
date added to LUP
2017-06-09 10:26:55
date last changed
2017-07-30 05:26:04
@article{5333a2c0-5201-4464-8a27-3f69dfea3628,
  abstract     = {<p>In order to reduce nitrogen oxides (NOx) and soot emissions while maintaining high thermal efficiency, more advanced combustion concepts have been developed over the years, such as Homogeneous Charge Compression Ignition (HCCI) and Partially Premixed Combustion (PPC), as possible combustion processes in commercial engines. Compared to HCCI, PPC has advantages of lower unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions; however, due to increased fuel stratifications, soot emissions can be a challenge when adding Exhaust-Gas Recirculation (EGR) gas. The current work presents particle size distribution measurements performed from HCCI-like combustion with very early (120 CAD BTDC) to PPC combustion with late injection timing (11 CAD BTDC) at two intake oxygen rates, 21% and 15% respectively. Particle size distributions were measured using a differential mobility spectrometer DMS500. Additionally, to get knowledge of the effect of injection timing on particle size distributions in PPC mode, measurements were performed in injection timing sweeps at engine speeds 800 rpm and 1600 rpm. Results show that, without EGR, throughout the injection timing from very early to late injection, a unimodal particle size distribution dominated by nucleation mode particles can be observed. Adding EGR, similar unimodal particle size distributions are obtained for early injection timings whereas bimodal size distributions appear for late injection timings when injecting goes into the bowl. The corresponding accumulation mode particle number rapidly increases and results in a high engine-out soot output. In PPC mode with high fuel stratification, a similar trend is found at engine speeds 800 rpm and 1600 rpm during injection timing sweeps. Retarding injection is generally found to reduce particle numbers in nucleation mode and increase numbers in accumulation mode, which leads to a higher soot mass output despite of a reduction in total particle numbers. It can be concluded that charge stratification and fuel impingement influence particle size distributions during injection timing variations.</p>},
  author       = {Shen, Mengqin and Tuner, Martin and Johansson, Bengt and Tunestal, Per and Pagels, Joakim},
  issn         = {0148-7191},
  language     = {eng},
  publisher    = {Society of Automotive Engineers},
  series       = {SAE Technical Papers},
  title        = {Influence of Injection Timing on Exhaust Particulate Matter Emissions of Gasoline in HCCI and PPC},
  url          = {http://dx.doi.org/10.4271/2016-01-2300},
  volume       = {2016-Octobeer},
  year         = {2016},
}