Effect of Closed Loop Fuel Control System Characteristics on Emissions from a Natural Gas-Fueled Engine

1993 ◽  
Author(s):  
Hannu E. Jääskeläinen ◽  
James S. Wallace
Kerntechnik ◽  
2009 ◽  
Vol 74 (5-6) ◽  
pp. 280-285
Author(s):  
M. Iqbal ◽  
J. Qadir ◽  
T. K. Bhatti ◽  
Q. Abbas ◽  
S. M. Mirza

2019 ◽  
pp. 64-72
Author(s):  
G.G. Arunyants

The results of analysis of problems of regulation of gas supply complex of Kaliningrad region and main ways to increase its efficiency, as well as basic solutions for creation of a software complex Т-GAZ-2 automated calculation of natural gas tariffs for ACS of gas supply system subjects, geographically distributed and information connected to the regional automated information and control system (RAIS).


Author(s):  
Axel Fehrenbacher ◽  
Christopher B. Smith ◽  
Neil A. Duffie ◽  
Nicola J. Ferrier ◽  
Frank E. Pfefferkorn ◽  
...  

The objective of this research is to develop a closed-loop control system for robotic friction stir welding (FSW) that simultaneously controls force and temperature in order to maintain weld quality under various process disturbances. FSW is a solid-state joining process enabling welds with excellent metallurgical and mechanical properties, as well as significant energy consumption and cost savings compared to traditional fusion welding processes. During FSW, several process parameter and condition variations (thermal constraints, material properties, geometry, etc.) are present. The FSW process can be sensitive to these variations, which are commonly present in a production environment; hence, there is a significant need to control the process to assure high weld quality. Reliable FSW for a wide range of applications will require closed-loop control of certain process parameters. A linear multi-input-multi-output process model has been developed that captures the dynamic relations between two process inputs (commanded spindle speed and commanded vertical tool position) and two process outputs (interface temperature and axial force). A closed-loop controller was implemented that combines temperature and force control on an industrial robotic FSW system. The performance of the combined control system was demonstrated with successful command tracking and disturbance rejection. Within a certain range, desired axial forces and interface temperatures are achieved by automatically adjusting the spindle speed and the vertical tool position at the same time. The axial force and interface temperature is maintained during both thermal and geometric disturbances and thus weld quality can be maintained for a variety of conditions in which each control strategy applied independently could fail.


Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4084
Author(s):  
Lorenzo Bongini ◽  
Rosa Anna Mastromauro ◽  
Daniele Sgrò ◽  
Fabrizio Malvaldi

Liquefied Natural Gas (LNG) plants are commonly island-operated weak grids where the interaction of high-power Variable Frequency Drives (VFDs) with the Turbine-Generator (TG) units might cause Sub-Synchronous Torsional Interaction (SSTI) phenomena. SSTI phenomena can lead the LNG plant to instability conditions. Each LNG plant configuration is characterized by a risk level, which is considered high when the electrical damping at the TG Torsional Natural Frequencies (TNFs) is negative. Starting from a real case study, a detailed electromechanical model of an LNG plant is presented. The model is comprehensive of the control system of the power conversion stage and of the TG unit. Sensitivity analysis, performed on control system parameters, allows one to detect the parameters that impact the electrical damping and the stability of the overall LNG plant. A complete simulation platform is developed. Experimental results are carried out on a real LNG plant considering four different configurations. The theoretical model and the simulation platform allow one to estimate the electrical damping and the results are confirmed by the experimental validation. It is demonstrated that fine tuning of the power conversion stage control parameters can reduce the risk related to torsional instability.


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