Deezler,
point 1) I said "more or less" because you need to add an heat loss map that was not shown in the paper.
From the paper: "The estimated combustion efficiency and the work conversion efficiency are shown in Figs. 27 and 28, respectively. From Eq.(12), we can also reconstruct a map of the heat-loss efficiency required to produce the measured fuel conversion efficiencies."
There are more heat losses at low EGR levels and advanced timing because of higher peak flame temperatures (2700 K at 21% O2 vs ~2100 K at 14% O2). See fig 6.
Quote:
|
Whoa, they allowed fueling rate to vary by up to 10%. That kind of throws a wrench in the whole thing. I'll keep reading...
|
How so? They controlled to keep IMEP at 3 bar. They just say that if if took more than a 10% adjustment in fueling rate to maintain their IMEP value the tests were stopped. You can chose to have IMEP vary at fixed fueling rate or have fueling vary at fixed IMEP as you change the EGR and SOI parameters, no?
Ernie,
"IGNITION DELAY
Ignition delay is influenced by both physical and chemical factors, and is thus affected by characteristics of the fuel injection equipment (injection pressure, nozzle hole diameter), injection timing (ambient temperature and density) and charge dilution (EGR rate) [22, 23]. Here, ignition delay is defined as the time from SOI to start-of- combustion (SOC), as determined by the crank angle at which 10% of the cumulative heat release occurred. This crank-angle correlates well with the beginning of rapid, high-temperature heat release. Figure 16 shows that, at the same injection timing, the ignition delay increases with decreasing O2 concentration."