Effects of Direct Fuel Injection Strategies on Cycle-by-Cycle Variability in a Gasoline Homogeneous Charge Compression Ignition Engine: Sample Entropy Analysis

Abstract

Abstract:In this study we summarize and analyze experimental observations of cyclic variability in homogeneous charge compression ignition (HCCI) combustion in a single-cylinder gasoline engine. The engine was configured with negative valve overlap (NVO) to trap residual gases from prior cycles and thus enable auto-ignition in successive cycles. Correlations were developed between different fuel injection strategies and cycle average combustion and work output profiles. Hypothesized physical mechanisms based on these correlations were then compared with trends in cycle-by-cycle predictability as revealed by sample entropy. The results of these comparisons help to clarify how fuel injection strategy can interact with prior cycle effects to affect combustion stability and so contribute to design control methods for HCCI engines.

Experimental study on detailed emissions speciation of an HCCI engine equipped with a three-way catalytic converter

“…Early NVO injection was applied at a start of injection (SOI) timing of À40 CA. Earlier studies showed that to a high extent exhaustfuel reactions happen at this injection timing [8]. As a result, high concentrations of pyrolysis products were observed in combustible mixture.…”

Dynamics and Entropy Analysis of a Frictionally Loaded Pendulum

“…The numerical procedure of entropy estimation (from experiments and mathematical models), in the forms presented above, have been applied to physical phenomena in the field of physiology [ 19 , 20 , 21 , 22 , 23 ], medicine [ 27 , 30 ], mechanics [ 13 , 14 , 16 , 18 ], and thermodynamics [ 15 ], etc. In the present paper, the CMSE is applied to signals of a pendulum system with a friction effect.…”

“…In this paper, we discuss the concept of multi-scaled entropy applied to response time series of dynamical systems in the case of a pendulum with a frictional load (previous related studies on mechanical systems include [ 13 , 14 , 15 , 16 ]). In the following sections, we define the mathematical model, introduce the entropy approach and discuss simulation results.…”

Impact of Spray Cone Angle on the Performances of Methane/Diesel RCCI Engine Combustion under Low Load Operating Conditions

“…It serves to reduce soot, Carbon Oxides (CO), and Nitrogen Oxides (NO x ) simultaneously. This option is commercially presented in three different approaches: 1/Homogeneous Charge Compression Ignition (HCCI) [5][6][7], which provides the ignition of a lean homogeneous air-fuel mixture; 2/Premixed Charge Compression Ignition (PCCI), is an adaptative form of HCCI, it controls combustion instability by a second injection to enrich wherever flame should be started; 3/Reactivity Controlled Compression Ignition (RCCI) [7,8], based on high reactivity fuel, that is, diesel and nheptane as well as a low reactive fuel such as gasoline, iso-octane, and natural gas. The LTC is based on a combination of injection timing, mixture homogeneity, and dual fuel mode.…”