scholarly journals An Ion Current Based Peak-Finding Algorithm for Pressure Peak Position Estimation

2000 ◽  
Author(s):  
Magnus Hellring ◽  
Ulf Holmberg
Keyword(s):  
Peak Position ◽  
Position Estimation ◽  
Ion Current ◽  
Peak Finding ◽  
Pressure Peak

A Simple Virtual Sensor for Combustion Timing

2003 ◽  
Vol 125 (3) ◽  
pp. 462-467 ◽  
Author(s):  
U. Holmberg ◽  
M. Hellring
Keyword(s):  
Closed Loop ◽  
Low Complexity ◽  
Peak Position ◽  
Ion Current ◽  
Virtual Sensor ◽  
Loop Control ◽  
Spark Plug ◽  
Crank Angle ◽  
Pressure Peak ◽  
Order Of Magnitude

A low-complexity virtual sensor for the pressure peak position of the crank angle in a spark-ignited car motor is proposed. The algorithm estimates the pressure peak position from the ion current, measured from the spark plug. The complexity of the algorithm is an order of magnitude smaller than any other proposed schemes. Still, performance is not sacrificed. Closed-loop control is demonstrated on a SAAB 9000 driven on the highway.

Modeling and Calculation of Initial Ignition Gas Pressure Flow through the Rigid Porous Media in 100 mm Ignition Simulator

2012 ◽  
Vol 560-561 ◽  
pp. 1103-1113
Author(s):  
Zheng Gang Xiao ◽  
Wei Dong He ◽  
San Jiu Ying ◽  
Fu Ming Xu
Keyword(s):  
Porous Media ◽  
Gas Flow ◽  
Ceramic Composite ◽  
Peak Position ◽  
Chamber Pressure ◽  
Lateral Side ◽  
Physical Processes ◽  
Local Permeability ◽  
Pressure Peak ◽  
Flow Through

To acquire better understanding of the early ignition phenomena in 100mm ignition simulator loaded with packed propellant bed, a theoretical model of ignition gas flow through rigid porous media is developed. Three pressure gauges are installed in the lateral side of ignition simulator for chamber pressure measurements after ignition. The pseupropellant loaded in the chamber is similar to the standard 13/19 single-base cylindrical propellant in size. It is composed of rigid ceramic composite with low thermo conductivity. It is assumed that the pseupropellant bed is rigid in contrast to the previous elastic porous media assumption. The calculated pressure values can be verified by the experimental data well at the low loading density of pseupropellant bed of 0.18 g/cm3. However, there is still error between the experimental and calculated results in the early pressure peak position close to the ignition primer when the loading density of pseupropellant bed increases to 0.73 and 1.06g/cm3, due to the change of local permeability of pseupropellant bed at high loading density, which is assumed a constant in the model for the modeling easily. The calculations can enable better understanding of physical processes of ignition gas flow in the ignition simulator loaded with the pseupropellant bed.

Experimental Study on Kilometer-Deep Shaft Working Face Advancing Step and Mining-Induced Stress Distribution Law

2013 ◽  
Vol 353-356 ◽  
pp. 1422-1426
Author(s):  
Chang Qing Ma ◽  
Bao Qing Dai ◽  
Guang Peng Qin
Keyword(s):  
Stress Distribution ◽  
Peak Position ◽  
Distribution Law ◽  
Support Design ◽  
Limit Value ◽  
Induced Stress ◽  
Working Face ◽  
Coal Wall ◽  
Pressure Peak ◽  
Sphere Of Influence

Based on the engineering background of Tangkou in Shandong province, this thesis carries out mining-induced stress distribution law comparative study and analysis of 2313 working face which is lying below-1100 miles, using methods of theoretical analysis, numerical simulation and field measurement, and obtains the limited synergistic effect of mining-induced stress variation and working face advancing steps under the condition of kilometer-deep shaft. That is, with the increase of working face advancing steps, there will be a corresponding increase in the advanced abutment pressure peak, sphere of influence, and the distance from the peak position to the coal wall, within its limit value. The conclusion of this study have some guidance for the safe production and support design of working face in kilometer-deep shaft.

scholarly journals Development and implementation of the linear phase algorithm in a two-dimensional sun-sensor

2021 ◽  
Author(s):  
Albert Kar-Kei Yam
Keyword(s):  
Embedded System ◽  
Performance Testing ◽  
Peak Position ◽  
Position Estimation ◽  
Dimensional System ◽  
Two Dimensional ◽  
Linear Phase ◽  
Estimation Performance ◽  
Sun Sensor ◽  
Two Dimensional System

The sub-pixel peak position estimation performance of the Linear Phase algorithm was enhanced and extended for use with a two-dimensional sensor. The two-dimensional system is composed of orthogonal pairs of slits diffracting light onto a single pixel array. The adaptation of the Linear Phase algorithm into the two-dimensional system was performed by manipulating the sensor image into two one-dimensional images. Performance testing used simulated sensor output and images attained from a real sun-sensor. The Linear Phase algorithm was then implemented into an embedded system to simulate onboard processing. A C8051 microcontroller was used as the embedded microcontroller. Results from the embedded processing were compared against the native Matlab implementation for consistency in sub-pixel peak position estimation performance. The Linear Phase algorithm was able to perform with excellent results, comparable to current two-dimensional sun-sensor algorithms.

Numerical Analysis of the Pressure Peak Position Shift With Deadrise Angle in Two-Dimensional Wedge Water Entry

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Xu Zhang ◽  
Peiqing Liu ◽  
Qiulin Qu ◽  
Yunke Zhao ◽  
Tianxiang Hu ◽  
...  
Keyword(s):  
Dynamic Pressure ◽  
Peak Position ◽  
Water Entry ◽  
Two Dimensional ◽  
Initial Stage ◽  
Pressure Term ◽  
Root Position ◽  
Pressure Peak ◽  
Position Shift ◽  
Volume Method

This study deals with the pressure peak position shift with deadrise angle during the initial phase of a two-dimensional (2D) wedge water entry. The finite volume method with volume of fluid (VOF) and dynamic mesh technique is used to simulate the water entry process of the 2D wedges with the moderate deadrise angles within the range α = 20 deg–60 deg. The results show that with the increasing deadrise angle, the pressure peak position shifts from the spray root to the wedge apex. And, the critical deadrise angle of pressure peak position shift is identified in the range between 40.8 deg and 41 deg, which is more precise than previous studies. In the initial stage of water entry of a 2D wedge, the pressure on wedge side is determined by the dynamic pressure term and unsteady term simultaneously. For the spray root position, at small deadrise angles, the unsteady term is stronger than the dynamic pressure term; at large deadrise angles, the former is weaker than the later.

scholarly journals Development and implementation of the linear phase algorithm in a two-dimensional sun-sensor

2021 ◽  
Author(s):  
Albert Kar-Kei Yam
Keyword(s):  
Embedded System ◽  
Performance Testing ◽  
Peak Position ◽  
Position Estimation ◽  
Dimensional System ◽  
Two Dimensional ◽  
Linear Phase ◽  
Estimation Performance ◽  
Sun Sensor ◽  
Two Dimensional System

The sub-pixel peak position estimation performance of the Linear Phase algorithm was enhanced and extended for use with a two-dimensional sensor. The two-dimensional system is composed of orthogonal pairs of slits diffracting light onto a single pixel array. The adaptation of the Linear Phase algorithm into the two-dimensional system was performed by manipulating the sensor image into two one-dimensional images. Performance testing used simulated sensor output and images attained from a real sun-sensor. The Linear Phase algorithm was then implemented into an embedded system to simulate onboard processing. A C8051 microcontroller was used as the embedded microcontroller. Results from the embedded processing were compared against the native Matlab implementation for consistency in sub-pixel peak position estimation performance. The Linear Phase algorithm was able to perform with excellent results, comparable to current two-dimensional sun-sensor algorithms.

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