Determining top-dead-center (tdc) of reciprocating compressor

Abstract

Various embodiments include approaches for determining a top-dead-center (TDC) of a reciprocating compressor. In some cases, an apparatus includes: a pressure transducer configured to measure pressure fluctuations inside a compressor cylinder and convert the pressure fluctuations into an asynchronous waveform; and at least one computing device operably connected with the pressure transducer, the at least one computing device configured to: extract a data set representing piston angles over a single revolution of a piston within the compressor cylinder from the asynchronous waveform; remove data representing invalid piston angles from the data set to form a refined data set; determine an average piston angle for the single revolution from the refined data set; and adjust the refined data set to identify a top-dead-center (TDC) position of the piston within the compressor cylinder.

I claim: 
     
         1 . An apparatus comprising:
 a pressure transducer configured to measure pressure fluctuations inside a compressor cylinder and convert the pressure fluctuations into an asynchronous waveform; and   at least one computing device operably connected with the pressure transducer, the at least one computing device configured to:
 extract a data set representing piston angles over a single revolution of a piston within the compressor cylinder from the asynchronous waveform; 
 remove data representing invalid piston angles from the data set to form a refined data set; 
 determine an average piston angle for the single revolution from the refined data set; and 
 adjust the refined data set to identify a top-dead-center (TDC) position of the piston within the compressor cylinder. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the at least one computing device is configured to remove the data representing invalid piston angles from the data set by identifying and excluding piston angles based upon a compression ratio of the single revolution of the piston within the compressor cylinder. 
     
     
         3 . The apparatus of  claim 1 , wherein the at least one computing device is configured to remove the data representing invalid piston angles from the data set by identifying and excluding piston angles based upon a volumetric efficiency of the single revolution of the piston within the compressor cylinder. 
     
     
         4 . The apparatus of  claim 1 , wherein the at least one computing device is configured to remove the data representing invalid piston angles from the data set by identifying and excluding piston angles based upon a clearance volume of the single revolution of the piston within the compressor cylinder. 
     
     
         5 . The apparatus of  claim 1 , wherein the at least one computing device is configured to adjust the refined data set to position a data value corresponding to the TDC position of the piston within the compressor as a first data value in the refined data set. 
     
     
         6 . The apparatus of  claim 1 , wherein the asynchronous waveform includes a series of uniformly spaced time domain data points. 
     
     
         7 . The apparatus of  claim 1 , wherein the at least one computing device is configured to extract the data set representing the piston angles over the single revolution using a threshold-hysteresis model. 
     
     
         8 . A system comprising:
 at least one computing device configured to identify a top-dead-center (TDC) position of a piston within a compressor cylinder by performing actions including:
 obtaining an asynchronous waveform indicating pressure fluctuations inside a compressor cylinder; 
 extracting a data set representing piston angles over a single revolution of the piston within the compressor cylinder from the asynchronous waveform; 
 removing data representing invalid piston angles from the data set to form a refined data set; 
 determining an average piston angle for the single revolution from the refined data set; and 
 adjusting the refined data set to identify the TDC position of the piston within the compressor cylinder. 
   
     
     
         9 . The system of  claim 8 , wherein the at least one computing device is configured to remove the data representing invalid piston angles from the data set by identifying and excluding piston angles based upon a compression ratio of the single revolution of the piston within the compressor cylinder. 
     
     
         10 . The system of  claim 8 , wherein the at least one computing device is configured to remove the data representing invalid piston angles from the data set by identifying and excluding piston angles based upon a volumetric efficiency of the single revolution of the piston within the compressor cylinder. 
     
     
         11 . The system of  claim 8 , wherein the at least one computing device is configured to remove the data representing invalid piston angles from the data set by identifying and excluding piston angles based upon a clearance volume of the single revolution of the piston within the compressor cylinder. 
     
     
         12 . The system of  claim 8 , wherein the at least one computing device is configured to adjust the refined data set to position a data value corresponding to the TDC position of the piston within the compressor as a first data value in the refined data set. 
     
     
         13 . The system of  claim 8 , wherein the asynchronous waveform includes a series of uniformly spaced time domain data points. 
     
     
         14 . The system of  claim 8 , wherein the at least one computing device is configured to extract the data set representing the piston angles over the single revolution using a threshold-hysteresis model. 
     
     
         15 . A computer program product comprising program code, which when executed on at least one at least one computing device, causes the at least one computing device to identify a top-dead-center (TDC) position of a piston within a compressor cylinder by performing actions including:
 obtaining an asynchronous waveform indicating pressure fluctuations inside the compressor cylinder;   extracting a data set representing piston angles over a single revolution of a piston within the compressor cylinder from the asynchronous waveform;   removing data representing invalid piston angles from the data set to form a refined data set;   determining an average piston angle for the single revolution from the refined data set; and   adjusting the refined data set to identify the top-dead-center (TDC) position of the piston within the compressor cylinder.   
     
     
         16 . The computer program product of  claim 15 , wherein the removing of the data representing invalid piston angles from the data set includes identifying and excluding piston angles based upon a compression ratio of the single revolution of the piston within the compressor cylinder. 
     
     
         17 . The computer program product of  claim 15 , wherein the removing of the data representing invalid piston angles from the data set includes identifying and excluding piston angles based upon a volumetric efficiency of the single revolution of the piston within the compressor cylinder. 
     
     
         18 . The computer program product of  claim 15 , wherein the removing of the data representing invalid piston angles from the data set includes identifying and excluding piston angles based upon a clearance volume of the single revolution of the piston within the compressor cylinder. 
     
     
         19 . The computer program product of  claim 15 , further comprising:
 adjusting the refined data set to position a data value corresponding to the TDC position of the piston within the compressor as a first data value in the refined data set.   
     
     
         20 . The computer program product of  claim 15 , wherein the asynchronous waveform includes a series of uniformly spaced data points, and wherein the extracting of the data set representing the piston angles over the single revolution includes using a threshold-hysteresis model.