Session: Technical Posters

Paper Number: 120666

120666 - Recurrence Quantification Analysis of Cyclic Combustion Variations in Dual Fuel Low Temperature Combustion 

Cyclic combustion variations, characterized by high coefficient of variation (COV) of indicated mean effective pressure (IMEP), are a well-known cause of engine instability, high unburned hydrocarbon (HC) and carbon monoxide (CO) emissions, and poor combustion and fuel conversion efficiencies with dual fuel low temperature combustion (LTC). These issues are especially exacerbated for engine operation at low loads. In previous research using IMEP “return maps” by the present research team, cyclic combustion variations in dual fuel LTC were shown to contain both stochastic and deterministic components, depending on operating conditions (e.g., start of injection (SOI) of the high-reactivity fuel).  Recurrence quantification analysis (RQA) has proven to be an effective tool in understanding the behavior of nonlinear dynamical systems. Recurrence plots (RPs) offer a qualitative means by which the dynamical behavior of a system can be described. On the other hand, RQA, provides metrics by which the system can be quantitatively characterized (e.g., recurrence rate, determinism, entropy, etc.). The aim of the present work is to characterize cyclic combustion variations in dual fuel LTC using RQA. To this end, a four-stroke single-cylinder research engine operating on dual-fuel LTC with natural gas as the low-reactivity fuel  is considered at different operating conditions. Time-series of engine parameters such as the in-cylinder pressure, the IMEP, and the heat release rate were collected experimentally over 1000 consecutive cycles. These time-series were used to reconstruct the phase space of the nonlinear dynamical system (i.e., the engine) and later to perform the RQA. Based on the RQA parameters, deterministic and stochastic behaviors are analyzed for very early and very late SOIs in dual fuel LTC with a specific focus on prior cycle effects on combustion stability at a low load of 5 bar IMEP and a constant speed of 1500 rev/min.

Presenting Author: Muhannad Hendy The University of Alabama

Presenting Author Biography: Muhannad Hendy is a Ph.D. student at The University of Alabama specializing in combustion analysis of dual fuel LTC.