"The objective of this study was to investigate the similarities between the development of nonlinear combustion variations in spark ignition engines under lean fueling and high levels of EGR using nitrogen to simulate EGR. Data analysis techniques from nonlinear dynamics were employed to determine patterns in heat release and indicated mean effective pressure (IMEP). The results from these tools indicate a transition from noisy stochastic variations near the stoichiometric fueling condition and under low levels of added inert, to noisy deterministic behavior, and back to noisy stochastic variations as the lean and EGR limits are reached, respectively.
The level of communication between successive cycles was found to be a strong function of the residual gas and fresh intake charge composition. Results from the lean equivalence ratio and constant fuel-to-oxidizer ratio EGR portions of the investigation showed that cyclic variations develop in the same manner, and the level of determinism is very similar in both systems. The constant fuel pulsewidth EGR tests resulted in lower levels of determinism than the other cases because the fresh combustion charge is already oxygen deficient and the addition of residual fuel does not enhance the combustion mixture as much as in the other two cases.
Examination of cyclic heat release values for both lean engine operation and operation using EGR with a constant fuel-to-oxidizer ratio revealed that lengthy, complex sequences of matching heat release values exist in and between the sets. The observation of nearly identical repeating heat release sequences may have important implications in the development of a control system for use with both lean and high EGR systems"--Abstract, page iii.
Drallmeier, J. A.
Isaac, Kakkattukuzhy M.
Bayless, Jerry R.
Mechanical and Aerospace Engineering
M.S. in Mechanical Engineering
University of Missouri--Rolla
xi, 106 pages
© 2000 Robert Wesley Sutton, All rights reserved.
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Sutton, Robert Wesley, "Investigation of cyclic dispersion under lean fueling and high levels of simulated EGR" (2000). Masters Theses. 1923.
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