Wavelet analysis of cycle-to-cycle pressure variations in an internal combustion engine

Abstract

Using a continuous wavelet transform we have analyzed the cycle-to-cycle variations of pressure in an internal combustion engine. The time series of maximum pressure variations are examined for different loading and their wavelet power spectrum is calculated for each load. From the wavelet power spectrum we detected the presence of long, intermediate and short-term periodicities in the pressure signal. It is found that depending on the load, the long and intermediate-term periodicities may span several cycles, whereas the short-period oscillations tend to appear intermittently. Knowledge of these periodicities may be useful to develop effective control strategies for efficient combustion.3

Analysis of pressure fluctuations in a natural gas engine under lean burn conditions

“…In order to develop effective control strategies for efficient combustion, it is important to understand the dynamics of cycle-to-cycle pressure variations [4][5][6]. Earlier studies on pressure fluctuations were carried out primarily in gasoline and diesel engines [7][8][9][10][11][12][13][14][15][16][17][18]. Using the methods of nonlinear dynamics and other techniques, researchers have investigated the complex dynamics of pressure fluctuations in these engines, including the possibility of chaotic oscillations [10][11][12][13][14][15][16].…”

“…In our recent work, we have used wavelet analysis to investigate the cycle-to-cycle variability of pressure oscillations in spark-ignition [17] and diesel [18] engines under different loading. In this paper, we perform wavelet analysis of cycle-to-cycle pressure -3 -variations in a natural gas-fired engine under different lean burn conditions.…”

Diagnostics of a combustion process in the aircraft radial engine

“…2a). Using the Morlet wavelet [6] one can see that the changing of the injection timing for about 150 cycles is working as a specific switch between different possible dynamical responses. Evidently, higher value of injection time which triggers appearance of oscillations with the period between 10-100 cycles.…”

“…The main activity of a new treatment are focused on the identification of a dynamical process. Following this direction, the recent papers employed the wavelet and multifractal analyses [6][7][8]. In this note we continue this specific analysis by considering aircraft multicylinder engine combustion process (Fig.…”

Analysis of repeatability of Diesel engine acceleration

“…The essential issue connected with the engine work is nonrepeatability in combustion. This phenomenon is also present in a stationary combustion process as cycle-to-cycle fluctuations of combustion determinants including cyclic indicated mean effective pressure, or heat release [2][3][4][5][6][7][8][9]. In case of acceleration, such fluctuations are superimposed on its increasing trend [1].…”