System comprising a refrigerant compressor and method for operating the refrigerant compressor

Abstract

A system includes a refrigerant compressor and an electronic control device therefor. The compressor includes a drive unit and a compression mechanism drivable thereby having a crankshaft-drivable piston. The control device captures and controls, in an open- and/or closed-loop manner, the crankshaft rotational speed and at least approximately captures the piston position. The control device determines an energy evaluation variable difference while the drive unit is switched off proportional to the energy required to perform one crankshaft revolution; at a measurement rotational speed, determines an energy evaluation variable proportional to the rotational energy at the measurement rotational speed; determines the number of crankshaft revolutions remaining, while the drive unit is switched off, until a standstill of the compression mechanism; and checks whether the remaining crankshaft revolutions upon switch-off of the drive unit at a reference piston position enable stopping of the compression mechanism in the suction phase thereof.

1 - 30  (canceled) 
     
     
         31 . A system comprising a refrigerant compressor and an electronic control device ( 13 ) for the refrigerant compressor ( 1 ), which refrigerant compressor ( 1 ) at least comprises
 a drive unit ( 16 ),   a compression mechanism ( 5 ) standing in an active connection with a rotor of the drive unit ( 16 ), having at least a piston ( 9 ) that can move back and forth in a cylinder of a cylinder block ( 8 ) and can be driven by way of a crankshaft ( 6 ), so as to cyclically draw refrigerant into the cylinder during a suction phase and compress the refrigerant in the cylinder during a compression phase that follows the suction phase,   wherein the electronic control device ( 13 ) is set up for   capturing and controlling and/or regulating a rotational speed (ω) of the crankshaft ( 6 ),   at least approximately capturing a piston position of the piston ( 9 ),   wherein the electronic control device ( 13 ) is set up for   when the drive unit ( 16 ) is shut off, determining an energy evaluation variable difference (W) that is proportional to the energy required for performing one crankshaft revolution,   at a measurement rotational speed (ω), determining an energy evaluation variable (E(ω)), which is proportional to the rotational energy at the measurement rotational speed (ω), as well determining the number of crankshaft revolutions (N) remaining until standstill of the compression mechanism ( 5 ) when the drive unit ( 16 ) is shut off,   checking whether the remaining crankshaft revolutions (N) at shut-off of the drive unit ( 16 ) at a reference piston position allow stopping of the compression mechanism ( 5 ) in its suction phase,   if necessary, turning the drive unit ( 16 ) on and, taking into consideration the energy evaluation variable difference (W), determining a shut-off rotational speed (ω shut-off ), at which the drive unit ( 16 ) should be shut off at the reference piston position, so as to bring about a standstill of the compression mechanism ( 5 ) in the suction phase and to shut off the drive unit ( 16 ) at the shut-off rotational speed (ω shut-off ),   or, if necessary, turning the drive unit ( 16 ) on and operating it at a limit rotational speed (ω limit ) that can be predetermined, and, taking into consideration the energy evaluation variable difference (W), determining a shut-off piston position and shutting off the drive unit ( 16 ) at the limit rotational speed (ω limit ) and the shut-off piston position.   
     
     
         32 . The system according to  claim 31 , wherein the control device ( 13 ) is set up for
 determining the energy evaluation variable difference (W) by means of formation of the difference of the energy evaluation variables (E(ω 1 ), E(ω 2 )) at two consecutive revolutions of the crankshaft ( 6 ), so as to be able to determine, by means of formation of the quotient of energy evaluation variable/energy evaluation variable difference (E(ω)/W), how many revolutions (N; N=E(ω)/W) the drive-free compression mechanism ( 5 ) can continue to run, proceeding from the measurement rotational speed (ω) and the reference piston position, wherein based on the post-decimal portion of the determined number of revolutions (N), it can be determined whether the compression mechanism ( 5 ) would come to a standstill in the suction phase or in the compression phase,   and, using the quotient formation and taking into consideration the post-decimal portion of the determined number of revolutions (N), driving the compression mechanism ( 5 ) in such a manner and shutting off the drive unit ( 16 ) in such a manner that the compression mechanism ( 5 ) comes to a standstill during the suction phase.   
     
     
         33 . The system according to  claim 31 , wherein the control device ( 13 ) is set up for shutting off the drive unit ( 16 ) and determining the energy evaluation variable difference (W) only when the rotational speed (ω) is greater than or equal to a minimum rotational speed (ω min ), preferably one that can be predetermined. 
     
     
         34 . The system according to  claim 31 , wherein the reference piston position is the top dead center of the piston ( 9 ) in the cylinder ( 8 ). 
     
     
         35 . The system according to  claim 31 , wherein the electronic control device ( 13 ) is set up for driving the compression mechanism ( 5 ) in such a manner that the shut-off rotational speed (ω shut-off ) is reached, and shutting off the drive unit ( 16 ) at the shut-off rotational speed (ω shut-off ) and the reference piston position, wherein the shut-off rotational speed (ω shut-off ) is determined in that
 the energy evaluation variable (E(ω b )) is determined at a determination rotational speed (ω b ) that functions as a measurement rotational speed, which is preferably present when the drive unit ( 16 ) is shut off to determine the energy evaluation variable difference (W), 
 the number of revolutions (N) is calculated by means of quotient formation: N=E(ω b )/W, 
 an adapted number of revolutions (N′) is calculated, in that the number of revolutions (N) is rounded up to the next greater whole number, and subsequently, an adaptation number between 0 and 1 is added, and 
 the shut-off rotational speed (ω shut-off ) is calculated within a constant factor (c), as the root of the product of the adapted number of revolutions (N′) and the energy evaluation variable difference (W):
   ω shut-off   =c *( N′*W ) 0.5 .
 
 
 
     
     
         36 . The system according to  claim 35 , wherein the adaptation number lies in the range of 0.1 to 0.4, preferably of 0.2 to 0.3, and wherein the reference piston position is the top dead center of the piston ( 9 ) in the cylinder ( 8 ). 
     
     
         37 . The system according to  claim 31 , wherein the electronic control device ( 13 ) is set up for driving the compression mechanism ( 5 ) in such a manner that the limit rotational speed (ω limit ) is reached, and shutting off the drive unit ( 16 ) at the limit rotational speed (ω limit ) and the shut-off piston position, wherein the shut-off piston position is determined in that
 the energy evaluation variable (E(ω limit )) is determined at the limit rotational speed (ω limit ), 
 the number of revolutions (N) is calculated by means of quotient formation: N=E(ω limit )/W, 
 the post-decimal portion of the number of revolutions (N) is determined, 
 an adapted post-decimal portion is determined in that an adaptation number between 0 and 1 is subtracted from the post-decimal portion of the number of revolutions (N), 
 the adapted post-decimal portion is converted to a piston position and this is deducted from the reference piston position. 
 
     
     
         38 . The system according to  claim 37 , wherein the adaptation number lies in the range of 0.1 to 0.4, preferably of 0.2 to 0.3, and wherein the reference piston position is the top dead center of the piston ( 9 ) in the cylinder ( 8 ). 
     
     
         39 . The system according to  claim 31 , wherein the electronic control device ( 13 ) is set up for
 a) shutting off the drive unit ( 16 ) and   b) when the drive unit ( 16 ) is shut off,   b1) determining the energy evaluation variable difference (W),   b2) determining the energy evaluation variable (E(ω run-down )) for a run-down rotational speed (ω run-down ) that is then present and functions as a measurement rotational speed,   b3) calculating the number of revolutions (N) by means of quotient formation: N=E (ω run-down )/W,   b4) and comparing the post-decimal portion of the number of revolutions (N) with an adaptation number between 0 and 1, and   c) if the post-decimal portion is greater than the adaptation number, driving the compression mechanism ( 5 ) only for the duration of part of a complete revolution of the crankshaft ( 6 ).   
     
     
         40 . The system according to  claim 39 , wherein the electronic control device ( 13 ) is set up for iteratively repeating at least the steps b 2 ), b 3 ), b 4 ), and c). 
     
     
         41 . The system according to  claim 39 , wherein the adaptation number lies in the range of 0.1 to 0.4, preferably of 0.2 to 0.3, and wherein the reference piston position is the top dead center of the piston ( 9 ) in the cylinder ( 8 ). 
     
     
         42 . The system according to  claim 31 , wherein the electronic control device ( 13 ) is set up for determining the energy evaluation variable (E(ω)) for the measurement rotational speed (ω) by means of squaring the measurement rotational speed (ω). 
     
     
         43 . The system according to  claim 32 , wherein the control device ( 13 ) is set up for determining the energy evaluation variable difference (W) in such a manner that multiple energy evaluation variable differences (W) are determined for rotational speeds (ω 1 , ω i+1 ) at two consecutive revolutions, in each instance, in a sequence of more than two consecutive revolutions, and an average value is formed from these energy evaluation variable differences (W). 
     
     
         44 . A method for operation of a refrigerant compressor having a drive unit ( 16 ), a compression mechanism ( 5 ) that can be driven by means of the drive unit ( 16 ), comprising a piston ( 9 ) as well as a crankshaft ( 6 ) that stands in connection with the latter by way of a connecting rod, characterized in that the method comprises the following steps:
 when the drive unit ( 16 ) is shut off, determining an energy evaluation variable difference (W), which is proportional to the energy required for performing one crankshaft revolution,   at a measurement rotational speed (ω), determining an energy evaluation variable (E(ω)), which is proportional to a rotational energy at the measurement rotational speed (ω), and calculating the number (N) of crankshaft revolutions remaining when the drive unit ( 16 ) is shut off, until a standstill of the compression mechanism occurs,   checking whether the remaining crankshaft revolutions (N) at shut-off of the drive unit ( 16 ) at a reference piston position allow stopping of the compression mechanism ( 5 ) in its suction phase,   if necessary, turning on the drive unit ( 16 ) and, taking into consideration the energy evaluation variable difference (W), determining a shut-off rotational speed (ω shut-off ), at which the drive unit ( 16 ) must be shut off at the reference piston position, so as to bring about a standstill of the compression mechanism ( 5 ) in the suction phase and shut-off of the drive unit ( 16 ) at the shut-off rotational speed (ω shut-off ),   or, if necessary, turning on the drive unit ( 16 ) and operating the same at a limit rotational speed (ω limit ) that can be predetermined and, taking into consideration the energy evaluation variable difference (W), determining a shut-off piston position and shut-off of the drive unit ( 16 ) at the limit rotational speed (ω limit ) and at the shut-off piston position.   
     
     
         45 . The method according to  claim 44 , wherein
 the energy evaluation variable difference (W) is determined by means of formation of the difference of the energy evaluation variables (E(ω 1 ), E(ω 2 )) at two consecutive revolutions of the crankshaft ( 6 ),   by means of formation of the quotient of energy evaluation variable/energy evaluation variable difference (E(ω)/W), it is determined how many revolutions (N; N=E(ω)/W) the drive-free compression mechanism ( 5 ) can continue to run, proceeding from the measurement rotational speed (ω) and the reference piston position, wherein it is determined, on the basis of the post-decimal portion of the determined number of revolutions (N), whether the compression mechanism ( 5 ) would come to a standstill in the suction phase or in the compression phase,   using the quotient formation and taking into consideration the post-decimal portion of the determined number of revolutions (N), the compression mechanism ( 5 ) is driven in such a manner, and the drive unit ( 16 ) is shut off in such a manner that the compression mechanism ( 5 ) comes to a standstill during the suction phase.