76 research outputs found
Combustion Process in a Spark Ignition Engine: Dynamics and Noise Level Estimation
We analyse the experimental time series of internal pressure in a four
cylinder spark ignition engine. In our experiment, performed for different
spark advance angles, apart from usual cyclic changes of engine pressure we
observed oscillations. These oscillations are with longer time scales ranging
from one to several hundred engine cycles depending on engine working
conditions. Basing on the pressure time dependence we have calculated the heat
released per cycle. Using the time series of heat release to calculate the
correlation coarse-grained entropy we estimated the noise level for internal
combustion process. Our results show that for a smaller spark advance angle the
system is more deterministic.Comment: 15 pages, 7 figures, submitted to CHAO
Estimation of a Noise Level Using Coarse-Grained Entropy of Experimental Time Series of Internal Pressure in a Combustion Engine
We report our results on non-periodic experimental time series of pressure in
a single cylinder spark ignition engine. The experiments were performed for
different levels of loading. We estimate the noise level in internal pressure
calculating the coarse-grained entropy from variations of maximal pressures in
successive cycles. The results show that the dynamics of the combustion is a
nonlinear multidimensional process mediated by noise. Our results show that so
defined level of noise in internal pressure is not monotonous function of
loading.Comment: 12 pages, 6 figure
Combustion variability and uniqueness in cylinders of a large power radial engine
This paper analyzes variability and uniqueness of a combustion process in the spark ignition radial engine having nine cylinders. In the case of single cylinder disturbances, multifractal approach is proposed to identify faults in the measured cylinder pressure. For better clarity, the pressure cyclic response is illustrated by means of wavelet results. The examined engine was powered by an electronic fuel injection, giving the possibility of varying doses supplied to the individual cylinders
Chaotic Combustion in Spark Ignition Engines
We analyse the combustion process in a spark ignition engine using the
experimental data of an internal pressure during the combustion process and
show that the system can be driven to chaotic behaviour. Our conclusion is
based on the observation of unperiodicity in the time series, suitable
stroboscopic maps and a complex structure of a reconstructed strange attractor.
This analysis can explain that in some circumstances the level of noise in
spark ignition engines increases considerably due to nonlinear dynamics of a
combustion process.Comment: 5 pages, figures can be obtained from
http://archimedes.pol.lublin.pl/~raf/graf/figures.pd
ICES2003-646 ADAPTIVE CONTROL OF THE IDLE SPEED
ABSTRACT Idle speed control of an spark ignition automotive engine based on adaptive techniques has been presented. In the paper the ignition advance control was activated to stabilise the idle speed. The adaptation of the spark advance angle requires defining an adaptive coefficient, which is a compromise between operation speed and estimation accuracy. The adaptive coefficient design was evaluated through engine testing, and the performance was compared with an up-to-date tuned PID controller. The success of the adaptive controller was demonstrated in engine testing. The controller tracks not only the set point speed but also shows robustness to the load torque disturbances
STRENGTH ANALYSIS OF A PROTOTYPE COMPOSITE HELICOPTER ROTOR BLADE SPAR
This paper investigates the strenght of a conceptual main rotor blade dedicated to an unmanned helicopter. The blade is made of smart materials in order to optimize the efficiency of the aircraft by increasing its aerodynamic performance. This purpose was achieved by performing a series of strength calculations for the blade of a prototype main rotor used in an unmanned helicopter. The calculations were done with the Finite Element Method (FEM) and software like CAE (Computer-Aided Engineering) which uses advanced techniques of computer modeling of load in composite structures. Our analysis included CAD (Computer-Aided Design) modeling the rotor blade, importing the solid model into the CAE software, defining the simulation boundary conditions and performing strength calculations of the blade spar for selected materials used in aviation, i.e. fiberglass and carbon fiber laminate. This paper presents the results and analysis of the numerical calculations
Nonperiodic Oscillations of Pressure in a Spark Ignition Engine
We report our results on non-periodic experimental time series of pressure in
a spark ignition engine. The experiments were performed for a low rotational
velocity of a crankshaft and a relatively large spark advance angle. We show
that the combustion process has many chaotic features. Surprisingly, the
reconstructed attractor has a characteristic butterfly shape similar to a
chaotic attractor of Lorentz type. The suitable recurrence plot shows that the
dynamics of the combustion is a nonlinear multidimensional process mediated by
stochastic noise.Comment: Latex, 6 pages, 5 figure
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