Theoretical investigation of flame propagation process in an SI engine running on gasoline–ethanol blends

Estimation of in-cylinder laminar flame speed from experimental data using two-zone combustion simulation of a spark ignition engine

“…[1,3,4,7,9,10]. Figure 3 shows the pressure trace for Royal Enfield 350cc PFI bullet engine using the pressure transducer and Engine Test Express software.…”

“…Based on coupled analysis of flame front location and cylinder pressure data, Blizard and Keck [3], (later extended by Keck [4] and Hakan Bayraktar [5,7]) have derived the following burning law:…”

“…where τ b = l t /S L is the characteristic reaction time to burn the mass of an eddy of size l t calculated empirically depending on maximum valve lift and ratio of inlet gas density to unburned gas density [4,7], m e is the mass entrained by the flame front, U t is the characteristic speed determined empirically depending on the mean inlet gas speed and the ratio of unburned gas density to inlet gas density [4,7], S L is the laminar flame speed and A f is flame surface area corresponding to enflamed volume V f are determined from a geometric model as described by Bayraktar [7]. With the help of the above Eqs.…”

In-cylinder pressure-based direct techniques and time frequency analysis for combustion diagnostics in IC engines

“…EOC can be evaluated in the HRR analysis as the crank angle at which x b reaches a certain threshold (e.g. 0.99) for single-zone models [29], or as the crank angle at which the theoretical x b reaches the experimental combustion efficiency measured from emissions for two-and multi-zone models. Otherwise, since HRR expresses the rate at which the fuel releases its chemical energy, a correspondence can be set between EOC and the crank angle at which the HRR falls below a minimum threshold, e.g.…”

Modelling cycle to cycle variations in an SI engine with detailed chemical kinetics

“…To run many cycles of a computational fluid dynamics (CFD) model with detailed chemistry however would be extremely computationally expensive. Less complex models exist that assume the flame is spherical and propagates at the turbulent flame speed from the spark [16][17][18]. In these models the cylinder is divided into unburned and burned zones and the burned zone may be subdivided into several zones that have burned at different times.…”