Abstract:
The present disclosure provides a device for variably controlling a flow rate of intake air of a turbocharger compressor including a housing, a compressor wheel, a sliding insert disposed in a straight tube in the housing coaxially with the straight tube, wherein the sliding insert variably adjusts an intake air recirculation passageway while moving closer to or farther from the straight tube in an axial direction, and a drive unit which provides power for moving the sliding insert, such that efficiency of the compressor may be improved because a flow rate of intake air is increased as the intake air is recirculated, and performance of an engine may be improved by improving performance of a turbocharger because an air amount required for the engine may be controlled by means of a variable slit structure.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of Korean Patent Application No. 10-2016-0043900, filed on Apr. 11, 2016, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The present disclosure relates to a device for variably controlling a flow rate of intake air of a turbocharger compressor. More particularly, it relates to a device for variably controlling a flow rate of intake air of a turbocharger. 
       BACKGROUND 
       [0003]    The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
         [0004]    In general, a turbocharger is a device which increases output of an engine of a vehicle by supercharging a cylinder of the engine with inflow air by rotating a turbine wheel and a compressor wheel by using high-temperature and high-pressure energy of exhaust gas being discharged from the engine. 
         [0005]    Usually, a commercially available diesel engine employs an intake air recirculation compressor housing which is typically applied to improve performance of the turbocharger compressor. 
         [0006]    Some intake air recirculation compressor housings, which are commercially available, include a slit for recirculating intake air, and the slit is provided in a form of a predetermined gap in the housing made of an aluminum material. 
         [0007]    For example, as illustrated in  FIG. 5 , the intake air recirculation compressor housing includes a compressor housing  10  for guiding intake air and discharge air, and a compressor wheel  11  for introducing air, and a slit  13  for recirculating intake air is formed in a straight tube  12  in the compressor housing  10  along a circumference of a front end portion of the compressor wheel  11 . 
         [0008]    Therefore, low-compressed and high-flow-rate intake air (air flow stabilization) is provided as air flows in a forward direction through the slit under a chock condition, and high-compressed and low-flow-rate intake air is provided as the intake air is recirculated when air flows in a reverse direction through the slit under a surge condition as indicated by arrows, thereby improving performance by expanding an operation region of the compressor. 
         [0009]    However, we have found that because a gap of the slit formed in the current intake air recirculation compressor housing is about 3 to 4 mm, and thus an area of an intake air recirculation passageway is fixed, there is a limitation in improving performance of the compressor. 
         [0010]    The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. 
         [0011]    Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
       SUMMARY 
       [0012]    The present disclosure provides a device for variably controlling a flow rate of intake air of a turbocharger compressor to adjust an area of an intake air recirculation passageway applied to recirculate intake air in an intake air recirculation compressor housing of a commercially available diesel engine, such that efficiency of the compressor may be improved because a flow rate of intake air is increased as the intake air is recirculated, and performance of an engine may be improved by improving performance of a turbocharger because an air amount required for the engine may be controlled by means of a variable slit structure. 
         [0013]    In one form, the present disclosure provides a device for variably controlling a flow rate of intake air of a turbocharger compressor, the device including: a compressor housing which guides intake air and discharge air; a compressor wheel for air intake; a sliding insert which is disposed in a straight tube in the compressor housing coaxially with the straight tube, and variably adjusts an intake air recirculation passageway while moving forward and rearward in an axial direction; and a drive unit which provides power for operating the sliding insert. 
         [0014]    In one form, the drive unit may include: an actuator which generates power; a rod-lever assembly which is connected to a rod of the actuator and rotatable; and a pinion gear which is mounted on the rod-lever assembly and moves the sliding insert. 
         [0015]    In another form, the pinion gear of the drive unit may be connected to and mesh with a rack gear disposed on the sliding insert and may move the sliding insert by means of a rack-and-pinion mechanism. 
         [0016]    In still another form, the actuator of the drive unit may be configured as a constant-pressure diaphragm type actuator. 
         [0017]    In yet another form, the sliding insert may be guided by being in contact with an inner wall of the straight tube by using a plurality of guide protrusions formed on an outer circumferential surface thereof when the sliding insert is moved. 
         [0018]    In still yet another form, the intake air recirculation passageway, which is changed in accordance with the movement of the sliding insert, may be formed in the form of a gap formed between an insert side inclined surface and a straight tube side inclined surface, and the gap formed between the insert side inclined surface and the straight tube side inclined surface may be structured to be inclined from a center to an outer periphery toward a front side where intake air inflows. The gap formed between the insert side inclined surface may be structured to be inclined from a center of the sliding insert to an outer periphery of the sliding insert toward a front side of the device where intake air inflows, and the straight tube side inclined surface may be structured to be inclined from a center of the straight tube to an outer periphery of the straight tube toward the front side of the device where intake air inflows. 
         [0019]    The device for variably controlling a flow rate of intake air of a turbocharger compressor, which is provided by the present disclosure, has at least the following advantages. 
         [0020]    First, an area of the intake air recirculation slit is variably expanded in the compressor housing of the turbocharger, such that it is possible to improve performance of the turbocharger by increasing the amount of intake air, and as a result, it is possible to improve performance of an engine and marketability of the engine. 
         [0021]    Second, with a structure that greatly expands an operation region, particularly, a surge region of the turbocharger compressor, it is possible to expand the surge region in the event of a surge phenomenon that instantaneously occurs when an accelerator pedal is pressed and then released, and as a result, it is possible to eliminate surge noise. 
         [0022]    It is understood that the term “vehicle” or “vehicular” or other similar terms as used herein are inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g. fuel derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles. 
         [0023]    Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0024]    The above and other features of the present disclosure will now be described in detail with reference to various forms thereof illustrated in the accompanying drawings, in which: 
           [0025]      FIG. 1  is a perspective view illustrating a device for variably controlling a flow rate of intake air of a turbocharger compressor according to one form of the present disclosure; 
           [0026]      FIG. 2  is a perspective view illustrating a state in which respective components of the device for variably controlling a flow rate of intake air of a turbocharger compressor according to one form of the present disclosure are disassembled; 
           [0027]      FIG. 3  is a cross-sectional view illustrating a narrow slit gap position and a state in which the device for variably controlling a flow rate of intake air of a turbocharger compressor according to one form of the present disclosure is operated; 
           [0028]      FIG. 4  is a cross-sectional view illustrating a wide slit gap position and a state in which the device for variably controlling a flow rate of intake air of a turbocharger compressor according to one form of the present disclosure is operated; and 
           [0029]      FIG. 5  is a front view and a cross-sectional view illustrating a typical intake air recirculation compressor housing. 
       
    
    
       [0030]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         [0031]    Reference numerals set forth in the Drawings include reference to the following elements as further discussed below: 
         [0032]      10 : compressor housing 
         [0033]      11 : compressor wheel 
         [0034]      12 : straight tube 
         [0035]      13 : intake air recirculation passageway 
         [0036]      14 : sliding insert 
         [0037]      15 : drive unit 
         [0038]      16 : actuator 
         [0039]      17 : rod-lever assembly 
         [0040]      17   a:  lever portion 
         [0041]      17   b:  rod portion 
         [0042]      18 : pinion gear 
         [0043]      19 : rack gear 
         [0044]      20 : guide protrusion 
         [0045]      21 : insert side inclined surface 
         [0046]      22 : straight tube side inclined surface 
         [0047]      23 : hose 
         [0048]      24 : bushing 
         [0049]      25 : gear housing 
         [0050]      26 : opening 
         [0051]    It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the disclosure. The specific design features of the present disclosure as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
         [0052]    In the figures, reference numbers refer to the same or equivalent parts of the present disclosure throughout the several figures of the drawings. 
       DETAILED DESCRIPTION 
       [0053]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
         [0054]    While the disclosure will be described in conjunction with various forms of the present disclosure, it will be understood that present description is not intended to limit the disclosure to forms. On the contrary, the disclosure is intended to cover various alternatives, modifications, equivalents and other forms, which may be included within the spirit and scope of the disclosure as defined by the present disclosure. 
         [0055]      FIG. 1  is a perspective view illustrating a device for variably controlling a flow rate of intake air of a turbocharger compressor according to one form of the present disclosure, and  FIG. 2  is a perspective view illustrating a state in which respective components of the device for variably controlling a flow rate of intake air of a turbocharger compressor according to one form of the present disclosure are disassembled. 
         [0056]    As illustrated in  FIGS. 1 and 2 , the device for variably controlling a flow rate of intake air of a turbocharger compressor includes a compressor housing  10  which has a straight tube  12  into which outside air flows, and a compressor wheel (designated by reference numeral  11  in  FIG. 5 ) which is positioned in the compressor housing  10 , for example, at an immediate rear side of the straight tube  12  and sucks air. 
         [0057]    Therefore, air, which inflows through the straight tube  12  when the compressor wheel  11  is rotated, may be discharged to an engine along a passageway in the compressor housing  10 . 
         [0058]    Here, because shapes of the compressor housing  10  and the compressor wheel  11  and a structure in which the compressor housing  10  and the compressor wheel  11  are coupled are similar to those of a typical intake air recirculation compressor housing, specific descriptions thereof will be omitted. 
         [0059]    The device for variably controlling a flow rate of intake air of a turbocharger compressor includes a sliding insert  14  which serves as a means for changing an area of an intake air recirculation passageway. 
         [0060]    The sliding insert  14  has a circular tube shape, and is disposed in the straight tube  12  coaxially with the straight tube  12  and installed to be slidable forward and rearward in an axial direction of the straight tube  12 . 
         [0061]    That is, a plurality of guide protrusions  20  is formed to protrude from an outer circumferential surface of the sliding insert  14  so as to be parallel with each other in a longitudinal direction and disposed in a circumferential direction at predetermined intervals. For example, as shown in  FIG. 2 , three guide protrusions  20  are disposed in the circumferential direction at an interval of approximately 120°, and the sliding insert  14  is guided by the straight tube  12  by means of the guide protrusions  20  when the sliding insert  14  slides forward and rearward in a state in which the sliding insert  14  is in contact with and engages an inner wall of the straight tube  12 . 
         [0062]    A rack gear  19  is formed at one side of the outer circumferential surface of the sliding insert  14 , for example, on a surface of any one guide protrusion  20  among the plurality of guide protrusions  20 , and the rack gear  19  is engaged with a pinion gear  18  to be described below, such that the sliding insert  14  may slide forward and rearward by the rack-and-pinion mechanism. 
         [0063]    In particular, with the forward and rearward sliding operation of the sliding insert  14 , an intake air recirculation passageway  13 , that is, a slit may be variably adjusted. 
         [0064]    To this end, the intake air recirculation passageway  13  is formed between a circumferential surface of a rear end portion of the sliding insert  14  and an inner circumferential surface of a rear end portion of the straight tube  12  which faces the rear end portion of the sliding insert  14 . 
         [0065]    That is, the intake air recirculation passageway  13  is formed in the form of a gap formed between an insert side inclined surface  21  formed at the circumferential surface of the rear end portion of the sliding insert  14  and a straight tube side inclined surface  22  formed at the inner circumferential surface of the rear end portion of the straight tube  12 . 
         [0066]    In this case, the gap formed between the insert side inclined surface  21  and the straight tube side inclined surface  22  may be structured to be inclined from a center to an outer periphery toward a front side where the intake air inflows. 
         [0067]    Therefore, a part of the intake air, which inflows through the straight tube  12 , may be discharged and flow forward through the intake air recirculation passageway  13  formed between the insert side inclined surface  21  and the straight tube side inclined surface  22 , and then flow back into the straight tube  12 . 
         [0068]    The device for variably controlling a flow rate of intake air of a turbocharger compressor includes a drive unit  15  as a means for moving the sliding insert  14  forward and rearward. 
         [0069]    The drive unit  15  includes an actuator  16  which generates power, a rod-lever assembly  17  which is connected to a rod of the actuator  16  and rotatable, and the pinion gear  18  which is mounted on the rod-lever assembly  17  and moves the sliding insert  14 . 
         [0070]    Here, the actuator  16  may be a constant-pressure diaphragm type actuator, and a hose  23 , which supplies pressure from an outlet of the compressor, is connected to the actuator  16 . 
         [0071]    The rod-lever assembly  17  includes a lever portion  17   a  which is connected to the rod of the actuator, and a rod portion  17   b  which has the pinion gear  18  mounted at a tip thereof, and is connected to the lever portion  17   a  at a rear end thereof. 
         [0072]    The rod-lever assembly  17  is, by means of the rod portion  17   b,  penetratively fastened to a bushing  24  installed on a front surface of the compressor housing  10 , and in this case, the rod-lever assembly  17  is freely rotatable around the rod portion  17   b.    
         [0073]    The pinion gear  18  at the tip of the rod portion of the rod-lever assembly  17 , which is installed as described above, is placed in a gear housing  25  formed at one side of the outer circumference of the straight tube  12 , and in this state, gear teeth of the pinion gear  18  are exposed through an opening  26  of the gear housing  25 , such that the pinion gear  18  may be engaged with the rack gear  19  formed on the sliding insert  14 . 
         [0074]    In this case, an actuator rod side connecting portion of the lever portion  17   a  of the rod-lever assembly  17  is eccentric to the rod portion  17   b,  and as a result, rectilinear motion of the actuator  16  may be converted into rotational motion of the rod portion  17   b  and the pinion gear  18 . 
         [0075]    Therefore, an operation of the device for variably controlling a flow rate of intake air of a turbocharger compressor, which is configured as described above, will be described below. 
         [0076]      FIGS. 3 and 4  are cross-sectional views illustrating states in which the device for variably controlling a flow rate of intake air of a turbocharger compressor according to one form of the present disclosure is operated, and illustrating a narrow slit gap position and a wide slit gap position, respectively. 
         [0077]    As illustrated in  FIGS. 3 and 4 , the device for variably controlling a flow rate of intake air of a turbocharger compressor adjusts a gap of the slit (intake air recirculation passageway) by moving a position of the sliding insert  14 . 
         [0078]    According to an operational mechanism, the gap of the slit may be adjusted through processes of transmitting pressure from the outlet of the compressor, operating the rod of the actuator  16 , rotating the rod-lever assembly  17 , rotating the pinion gear  18  connected to the rod-lever assembly  17 , and moving a position of the sliding insert  14 . 
         [0079]    That is, the gap of the slit is increased when pressure is supplied to the actuator, and the gap of the slit is decreased when pressure is not supplied to the actuator. 
         [0080]    Here, the actuator  16  is operated over tension of a spring which is initially set in accordance with tension of the constant-pressure diaphragm type spring. 
         [0081]    An initial position of the sliding insert  14  is set such that the gap of the slit is about 3 to 4 mm which is similar to the gap of the existing fixed type intake air recirculation compressor housing, and the sliding insert  14  is operated in a direction in which the gap of the slit is increased. 
         [0082]    Therefore, the effect of the device for variably controlling a flow rate of intake air of a turbocharger compressor according to the present disclosure is increased in a surge region where a flow rate of intake air is insufficient and pressure is high at the outlet of the compressor. 
         [0083]    In a case in which pressure is high at the outlet of the compressor, the gap of the slit is further increased, and a flow rate of intake air, which recirculates and inflows, is further increased, such that a surge line of the compressor ensures a larger operation region, and an operation region is slightly increased even in a chock line due to an increase in flow rate and flow stabilization. 
         [0084]    The disclosure has been described in detail with reference to various forms. However, it will be appreciated by those skilled in the art that changes may be made in these forms without departing from the principles and spirit of the present disclosure. 
         [0085]    The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.