ARC Researchers at ASME 2015 ICEF
Internal Combustion Engine Division Fall Technical Conference
(November 8-11, 2015 at Houston, TX)
ARC researchers (principal investigators in bold) will be presenting their latest research developments. In this conference, their papers were not ARC funded.
Session: 3-4 ICE Fundamentals
Tuesday, November 10, 2015 10:30 AM-12:00 PM
ICEF2015-1173 Fast Computation of Combustion Phasing and Its Influence on Classifying Random or Deterministic Patterns
Huan Lian, Jason Martz, Niket Prakash, Anna Stefanopoulou, University Of Michigan
Abstract: The classification between a sequence of highly variable combustion events that have an underlying deterministic pattern and a sequence of combustion events with similar level of variability but random characteristics is important for control of combustion phasing. In the case of high cyclic variation (CV) with underlying deterministic patterns, it is possible to apply closed loop combustion control on a cyclic-basis with a fixed mean value, such as injection timing in homogeneous charge compression ignition (HCCI) or spark timing in spark ignition (SI) applications, to contract the CV. In the case of a random distribution, the high CV can be avoided by shifting operating conditions away from the unstable region via advancing or retarding the injection timing or the spark timing in the mean-sense.
Therefore, the focus of this paper is on the various methods of computing CA50 for analysing and classifying cycle-to-cycle variability. The assumptions made to establish fast and possibly on-line methods can alter the distribution of the calculated parameters from cycle-to-cycle, possibly leading to incorrect pattern interpretation and improper control action.
Finally, we apply a statistical technique named "permutation entropy" for the first time on classifying combustion patterns in HCCI and SI engine. Then the various fast methods for computing CA50 feed the two statistical methods, permutation and the Shannon entropy, and their differences and similarities are highlighted.
Session: 2-1 Compression Ignition I: Dual Fuel
Monday, November 09, 2015 10:00 AM-12:00 PM
ICEF2015-115 RCCI of Synthetic Kerosene with PFI of n-Butanol – Combustion and Emissions Characteristics
Valentin Soloiu, Martin Muinos, Tyler Naes, Spencer Harp, Georgia Southern University
Marcis Jansons, Wayne State University
Abstract: In this study, the combustion and emissions characteristics of Reactivity Controlled Compression Ignition (RCCI) obtained by direct injection (DI) of S8 and port fuel injection (PFI) of n-butanol were compared with RCCI of ultra-low sulfur diesel #2 (ULSD#2) and PFI of n-butanol at 6 bar indicated mean effective pressure (IMEP) and 1500 rpm. S8 is a synthetic paraffinic kerosene (C6-C18) developed by Syntroleum and is derived from natural gas. S8 is a Fischer-Tropsch fuel that contains a low aromatic percentage (0.5 vol. %) and has a cetane number of 63 versus 47 of ULSD#2. Baselines of DI conventional diesel combustion (CDC), with 100% ULSD#2 and also DI of S8 were conducted. For both RCCI cases, the mass ratio of DI to PFI was set at 1:1. The ignition delay for the ULSD#2 baseline was found to be 10.9 CAD (1.21 ms) and for S8 was shorter at 10.1 CAD (1.12 ms). In RCCI, the premixed charge combustion has been split into two regions of high temperature heat release, an early one BTDC from ignition of ULSD#2 or S8, and a second stage, ATDC from n-butanol combustion. RCCI with n-butanol increased the NOx because the n-butanol contains 21% oxygen, while S8 alone produced 30% less NOx emissions when compared to the ULSD#2 baseline. The RCCI reduced soot by 80-90% (more efficient for S8). However, S8 alone showed a considerable increase in soot emissions compared with ULSD#2. The indicated thermal efficiency was the highest for the ULSD#2 and S8 baseline at 44%. The RCCI strategies showed a decrease in indicated thermal efficiency at 40% ULSD#2-RCCI and 42% and for S8-RCCI, respectively. S8 as a single fuel proved to be a very capable alternative to ULSD#2 in terms of combustion performance nevertheless, exhibited higher soot emissions that have been mitigated with the RCCI strategy without penalty in engine performance.