IC-Engine Intake Acoustic Source Data from Non-Linear Simulations

Author(s):  
Magnus Knutsson ◽  
Hans Bodén
2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Antti Hynninen ◽  
Raimo Turunen ◽  
Mats Åbom ◽  
Hans Bodén

Knowledge of the acoustic source characteristics of internal combustion engines (IC-engines) is of great importance when designing the exhaust duct system and its components to withstand the resulting dynamic loads and to reduce the exhaust noise emission. The goal of the present study is to numerically and experimentally investigate the medium speed IC-engine acoustic source characteristics, not only in the plane wave range but also in the high frequency range. The low frequency acoustic source characteristics were predicted by simulating the acoustic multiload measurements by using a one-dimensional process simulation code. The low frequency in-duct exhaust noise of a medium speed IC-engine can be quite accurately predicted. The high frequency source data is estimated by averaging the measured acoustic pressures with different methods; using the simple cross-spectra averaging method seems promising in this instance.


Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 940
Author(s):  
Zijing Wang ◽  
Mihai-Alin Badiu ◽  
Justin P. Coon

The age of information (AoI) has been widely used to quantify the information freshness in real-time status update systems. As the AoI is independent of the inherent property of the source data and the context, we introduce a mutual information-based value of information (VoI) framework for hidden Markov models. In this paper, we investigate the VoI and its relationship to the AoI for a noisy Ornstein–Uhlenbeck (OU) process. We explore the effects of correlation and noise on their relationship, and find logarithmic, exponential and linear dependencies between the two in three different regimes. This gives the formal justification for the selection of non-linear AoI functions previously reported in other works. Moreover, we study the statistical properties of the VoI in the example of a queue model, deriving its distribution functions and moments. The lower and upper bounds of the average VoI are also analysed, which can be used for the design and optimisation of freshness-aware networks. Numerical results are presented and further show that, compared with the traditional linear age and some basic non-linear age functions, the proposed VoI framework is more general and suitable for various contexts.


2017 ◽  
Vol 126 ◽  
pp. 1-18
Author(s):  
Antti Hynninen ◽  
Heikki Isomoisio ◽  
Jukka Tanttari

2010 ◽  
Vol 44-47 ◽  
pp. 3413-3417
Author(s):  
Bin Zhang ◽  
Xue Jun Liu ◽  
Rui Xiang Song ◽  
Bin Liu ◽  
Tao Feng

The physical insight of the source data of two-port acoustic source model for a duct is studied in theoretical, experimental and numerical aspects respectively. Under the ideal acoustic boundary condition of full absorption at the duct ends, the state equation of two-port acoustic source model is discussed, and the physical insight of the source data is obtained through theoretical derivation. The experimental model of two-port acoustic source is established, and the source data have been measured by the method “with an external source”. The physical meaning of source data has been demonstrated through the experimental method. The numerical simulating model for the experiment system is built, and the source data obtained numerically are compared with those measured experimentally for research. From the comparison, it is concluded that the source data of two-port acoustic source model are the traveling wave propagating outside along the duct under the acoustic boundary condition of full absorption at duct ends.


2016 ◽  
Vol 39 (2) ◽  
pp. 208-223 ◽  
Author(s):  
Yiran Shi ◽  
Ding-Li Yu ◽  
Yantao Tian ◽  
Yaowu Shi

Modelling of non-linear dynamics of an air manifold and fuel injection in an internal combustion (IC) engine is investigated in this paper using the Volterra series model. Volterra model-based non-linear model predictive control (NMPC) is then developed to regulate the air–fuel ratio (AFR) at the stoichiometric value. Due to the significant difference between the time constants of the air manifold dynamics and fuel injection dynamics, the traditional Volterra model is unable to achieve a proper compromise between model accuracy and complexity. A novel method is therefore developed in this paper by using different sampling periods, to reduce the input terms significantly while maintaining the accuracy of the model. The developed NMPC system is applied to a widely used IC engine benchmark, the mean value engine model. The performance of the controlled engine under real-time simulation in the environment of dSPACE was evaluated. The simulation results show a significant improvement of the controlled performance compared with a feed-forward plus PI feedback control.


Sign in / Sign up

Export Citation Format

Share Document