Title: Effect of engine conditions and injection timing on piston-top fuel films for stratified direct-injection spark-ignition operation using E30

Abstract

Mid-level ethanol/gasoline blends can provide knock resistance benefits for stoichiometric spark-ignition engine operation, but previous studies have identified challenges associated with spray impingement and wall wetting, leading to excessive particulate matter emissions. At the same time, stratified-charge spark-ignition operation can provide increased thermal efficiency, but care has to be exercised to avoid excessive in-cylinder soot formation. In support of the use of mid-level ethanol/gasoline blends in advanced spark-ignition engines, this study presents spray and fuel-film measurements in a direct-injection spark-ignition engine operated with a 30 vol.%/70 vol.% ethanol/gasoline blend (E30). Crank-angle resolved fuel-film measurements at the piston surface are conducted using two different implementations of the refractive index matching technique. A small-angle refractive index matching implementation allows quantification of the wetted area, while a large-angle refractive index matching implementation enables semi-quantitative measurements of fuel-film thickness and volume, in addition to fuel-film area. The fuel-film measurements show that both the amount of fuel deposited on the piston and the shape of the fuel-film patterns are strongly influenced by the injection timing, duration, intake pressure, and coolant temperature. For combinations of high in-cylinder gas density and long injection duration, merging of the individual spray plumes, commonly referred to as spray collapse, canmore » cause a dramatic change to the shape and thickness of the wall fuel films. Overall, the study provides guidance to engine designers aiming at minimizing wall wetting through tailored combinations of injection timings and durations.« less

Authors:

Ding, Carl-Philipp ^[1]; Vuilleumier, David ^[2]; Kim, Namho ^[2]; Reuss, David L. ^[2]; Sjöberg, Magnus  ^[2];

• Search DOE PAGES for author "Sjöberg, Magnus"
• Search DOE PAGES for ORCID "0000-0002-4288-5607"
• Search orcid.org for ORCID "0000-0002-4288-5607"

Böhm, Benjamin ^[1]

---

+ Show Author Affiliations

1. Fachgebiet Reaktive Strömungen und Messtechnik (RSM), Technische Universität Darmstadt, Darmstadt, Germany
2. Sandia National Laboratories, Livermore, CA, USA

Publication Date:

2019-09-05

Sponsoring Org.:

USDOE

OSTI Identifier:

1566207

Resource Type:

Published Article

Journal Name:

International Journal of Engine Research

Additional Journal Information:

Journal Name: International Journal of Engine Research Journal Volume: 21 Journal Issue: 2; Journal ID: ISSN 1468-0874

Publisher:

SAGE Publications

Country of Publication:

United Kingdom

Language:

English