Patent Publication Number: US-2021180582-A1

Title: Cylinder head for a compressor

Description:
The invention relates to a cylinder head for a compressor, in particular a reciprocating compressor for use in motor vehicles, which is suitable for compressing a compressible working medium, in particular air, for use in a compressed air supply device of a motor vehicle. 
     Reciprocating compressors and/or compressors or air compressors serve for the compression of gases, for example air, which is used as a working medium for operating various systems in a motor vehicle. 
     The reciprocating compressor substantially consists of a main body and/or crankshaft housing or cylinder housing, in which at least one reciprocating piston is arranged, and a cylinder head. During operation, ambient air is suctioned into the reciprocating piston chamber via an inlet channel, the ambient air is compressed and subsequently passed on via a channel. In the case of a multi-stage reciprocating compressor, the compressed air is passed on into a further and/or downstream compressor stage and is compressed further therein. The compressed air is subsequently conducted into the compressed air tank via an air treatment unit. 
     Such a cylinder head is disclosed, for example, in DE 10 2015 225 069 A1 and is composed of a plurality of components which are arranged in layers one on top of the other. The components form various channels or chambers through which air or a cooling medium, in particular cooling water, flows. For cooling the compressed air, the guidance of the channel through the cylinder head and/or through the individual components of the cylinder head is selected such that the channel is as long as possible and is guided as closely as possible past the cooling medium channel. Due to the compact design of the cylinder head, however, it is not possible to avoid that a heat exchange takes place between the airflows which are guided through the cylinder head and which have different temperatures. 
     In this case, the heat transfer between the airflows which are at different temperatures takes place via the partition walls of the channels. Due to the metal design of these partition walls the thermal conductivity is very good. A drawback is that this heat transfer negatively influences the efficiency of the reciprocating compressor. 
     The object of the invention is to improve the cylinder head construction such that the efficiency of the reciprocating compressor is increased. 
     The object is achieved according to the invention by a cylinder head embodiment which is constructed such that an undesired heat transfer between two fluid flows is minimized. Further advantageous features of the embodiment according to the invention are disclosed in the subclaims. 
     A cylinder head for a reciprocating compressor for compressing a compressible working medium, comprising a cylinder cover and a valve carrier plate, is proposed, said cylinder head being constructed as follows and having the following features. 
     An intermediate element is arranged between the cylinder cover and the valve carrier plate, and a plurality a channel sections and/or chambers are arranged between the valve carrier plate and the intermediate element and between the cylinder cover and the intermediate element and/or are formed thereby, through which various media flows can be conducted. In order to improve the efficiency of the reciprocating compressor, one or more insulation chambers are provided in the cylinder head, which at least in regions thermally insulate the channel sections and/or chambers from one another. 
     In a preferred embodiment, for example in a single-stage reciprocating compressor, an inlet chamber and an outlet chamber are provided, the insulation chamber being arranged therebetween. In the case of multi-piston compressors or even multi-stage compressors, further insulation chambers may also be arranged between the different temperature ranges. 
     Moreover, an outlet channel may be provided in the cylinder head, wherein the insulation chamber at least in regions thermally insulates the inlet chamber and the outlet chamber relative to the outlet channel. 
     The insulation chambers may be substantially formed by recesses in the valve carrier plate and/or in the cylinder cover. In this case, therefore, the recesses are closed by means of the intermediate element. 
     Preferably, the insulation chambers contain enclosed ambient air. During assembly, therefore, no additional working step needs to be factored in. Alternatively, however, the insulation chambers may also be filled with an insulating material or contain a vacuum. 
     It may also be provided that the intermediate element has connection openings which connect together the channel sections and/or chambers in the valve carrier plate and in the cylinder cover. Thus the airflow and/or the cooling medium flow may pass from one plane to another. The intermediate element may also be a sealing element. 
     In one embodiment, the cylinder head may be a cylinder head for a multi-stage reciprocating compressor, wherein the inlet chambers of the compressor stages are arranged between the outlet chambers of the compressor stages. 
     Moreover, an insulation chamber may be arranged between the outlet chamber and the inlet chamber of the second compressor stage and/or between the inlet chamber of the second compressor stage and the inlet chamber of the first compressor stage. 
    
    
     
       By means of exemplary embodiments, further advantageous features of the invention are described with reference to the drawings. The cited features may not only be used advantageously in the combination shown but may also be individually combined together. The figures show in detail: 
         FIG. 1  shows the reciprocating compressor with the cylinder head (section B-B) 
         FIG. 2  shows a plan view of the cylinder head (section A-A) 
         FIG. 3  shows an alternative construction for a cylinder head 
         FIG. 1  shows a two-stage reciprocating compressor  1  and/or compressor with a cylinder head  2  in section. The section line may be seen in  FIG. 2 . The cylinder head  2  is composed of the valve carrier plate  5 , the cylinder head cover  7  and an intermediate element  6  arranged therebetween. 
     
    
    
       FIG. 2  shows a plan view of the cylinder head  2 , wherein the section line A-A of  FIG. 1  may be seen. 
     The reciprocating compressor  1  has a water cooling system which runs through the cylinder housing  3  and through the cylinder head  2 . The exact path of the cooling medium channels  8 . 1  and  8 . 2 , which are connected together so that a flow of cooling medium may flow through the two regions, is not able to be identified. 
     As may also be seen in  FIGS. 1 and 2 , a plurality of channel sections  8 . 1 ,  10  run between the valve carrier plate  5  and the intermediate element  6  and between the cylinder cover  7  and the intermediate element  6  and a plurality of chambers  14 . 1 ,  14 . 2 ,  15 . 1  and  15 . 2  are present. Moreover, a plurality of insulation chambers  9 . 1 ,  9 . 2  are arranged in the cylinder head  2 . 
     In this exemplary embodiment the insulation chambers  9 . 1  and  9 . 2  are arranged such that, in particular, the channel section  10 , through which the hot compressed air of the second compressor stage  18  is conducted to the outlet opening  20 , is insulated from the chambers  14 . 1 ,  14 . 2 ,  15 . 1  and  15 . 2 . This prevents undesired heating of the intake air, in particular the cool ambient air, and the precompressed air which is conducted from the first compressor stage  17  to the second compressor stage  18 . 
     The path of the insulation chambers may be seen in  FIG. 2 , wherein it may be identified that a complete separation is not necessarily achieved between the hot and cold airflows by means of the insulation chambers. However, the direct heat transfer through the metal partition walls is at least significantly reduced by the partial insulation. 
     As may be identified, the insulation chambers  9 . 1  and  9 . 2  are sealed cavities which are formed substantially by recesses in the valve carrier plate  5  and in the cylinder cover  7  and are closed by the intermediate element  6 . The insulation chambers  9 . 1  and  9 . 2  are filled with ambient air which has been enclosed during assembly. 
     In the case of two-stage reciprocating compressors  1  it is essential that the precompressed air from the first compressor stage  17  is cooled as far as possible before it is suctioned into the second compressor stage  18  via the inlet chamber  14 . 2 . In order to achieve this, the airflow is conducted from the outlet chamber  15 . 1  of the first compressor stage  17  through a connecting channel  19  in the cylinder housing  3 . The walls of the connecting channel  19  are in contact at one point with the cooling channel  8 . 2  and additionally have a large cooling surface relative to the ambient air. 
       FIG. 3  shows an alternative construction for a cylinder head  1 . This cylinder head differs substantially by the arrangement of the channels and chambers. Thus in this case the insulation chambers  9 . 3  are arranged between the connecting channel  19  and the compressed air channel  10 . The insulation chamber  9 . 3  is incorporated in the valve carrier plate  5  and is closed by the sealing element  4 . 
     LIST OF REFERENCE NUMERALS 
     
         
           1  Compressor 
           2  Cylinder head 
           3  Cylinder housing 
           4  Sealing element 
           5  Valve carrier plate 
           6  Intermediate element 
           7  Cylinder cover 
           8  Cooling medium channel 
           9 . 1  . . .  9 . 3  Insulation chamber 
           10  Compressed air channel 
           11  Intake air channel second stage 
           12  Outlet valve 
           13  Inlet valve 
           14 . 1 ,  14 . 2  Inlet chamber 
           15 . 1 ,  15 . 2  Outlet chamber 
           16  Reciprocating piston chamber 
           17  First compressor stage 
           18  Second compressor stage 
           19  Connecting channel 
           20  Outlet opening