Patent Publication Number: US-10767396-B2

Title: Vehicular latch assembly with latch mechanism having pop-off sound reduction

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/375,187 filed Aug. 15, 2016. The entire disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates generally to closure latch assemblies for use in motor vehicle closure systems. More particularly, the present disclosure is directed to a closure latch assembly for a closure panel and which is equipped with a latch mechanism providing a pop-off sound reduction function. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     In view of increased consumer demand for motor vehicles equipped with advanced comfort and convenience features, many modern motor vehicles are now provided with keyless passive entry systems to permit locking and release of closure panels (i.e., doors, tailgates, liftgates and decklids) without use of a traditional key-type entry system. In this regard, popular features now available with many vehicle closure latch systems include power locking/unlocking and power release functionality. These “powered” features are typically provided by a closure latch assembly mounted to the closure panel and which includes a ratchet and pawl type of latch mechanism controlled via at least one electric actuator. In operation, the closure panel is latched in a closed position by virtue of a ratchet being positioned in a striker capture position to releaseably retain a striker that is mounted to a structural portion of the vehicle. The ratchet is held in its striker capture position by a pawl engaging the ratchet, when the pawl is located in a ratchet holding position. The closure latch assembly is operated in a “latched” mode when the pawl is located in its ratchet holding position. To release the closure panel from its closed position, the electric actuator is actuated to move the pawl from its ratchet holding position into a ratchet releasing position, whereby a ratchet biasing arrangement forcibly pivots the ratchet from its striker capture position into a striker release position so as to release the striker. The closure latch assembly is operating in an “unlatched” mode when the pawl is located in its ratchet releasing position. As an alternative to such single ratchet/pawl latch mechanisms, it is also known to employ a double ratchet/pawl type of latch mechanism within the closure latch assembly to reduce the release effort required for the electric actuator to release the latch mechanism during a power release operation. 
     To ensure that precipitation and road debris do not enter the vehicle, vehicle closure panels are equipped with weather seals around their peripheral edge and which are configured to seal against a mating surface of the vehicle body surrounding the closure opening. These weather seals also function to reduce wind noise. The weather seals are typically made from an elastomeric material and are configured to compress upon closing and latching of the closure panel by virtue of the closure latch assembly. As is recognized, increasing the compressive clamping force applied to the weather seals provides improved noise reduction within the passenger compartment. However, with the weather seals held in a highly compressed condition, they tend to force the closure panel toward its open position and this “opening” force is resisted by the latch mechanism of the closure latch assembly. Because the seal loads exerted on the latch mechanism are increased, the forces required to release the latch mechanism are also increased which, in turn, impacts the size and power requirements of the electric actuator. Further, an audible “pop-off” sound is sometimes generated following actuation of the electric actuator during the power release operation due to the quick release of the seal loads as the striker engages the ratchet of the latch mechanism as the ratchet is driven toward its striker release position. 
     To address this dichotomy between high seal loads and low release efforts, it is known to provide an arrangement for controllably releasing the seal loading in coordination with release of the latch mechanism. For example, European Publication No. EP1176273 discloses a single ratchet/double pawl type of power-operated latch mechanism that is configured to provide a progressive releasing of the ratchet for reducing noise associated with its release. In addition, European Publication EP0978609 utilizes an eccentric mechanism in association with a single ratchet/pawl type of latch mechanism to reduce seal loads prior to release of the ratchet. 
     While current closure latch assemblies are sufficient to meet regulatory requirements and provide enhanced comfort and convenience, a need still exists to advance the technology and provide alternative closure latch assemblies and arrangements that address and overcome at least some of the known shortcomings, particularly elimination of pop-off noise. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not intended to be a comprehensive and exhaustive listing of all features, aspects, objectives and embodiments associated with the full scope of protection afforded to the inventive concepts of the present disclosure. 
     It is an aspect of the present disclosure to provide a closure latch assembly for use with a closure panel associated with a motor vehicle closure system providing a mechanism for reducing the pop-off sound attributable to seal loads upon release of the closure latch assembly. 
     It is a related aspect of the present disclosure to provide a closure latch assembly having a latch mechanism operable for releaseably latching a striker in a striker capture position in response to movement of the closure panel from an open position to a fully-closed position, and a pop-off sound reduction mechanism configured to provide opening resistance upon initial release of the latch mechanism so as to reduce exit velocity and acceleration characteristics of the striker as it exits the closure latch assembly. 
     It is another related aspect of the present disclosure to equip the closure latch assembly with a ratchet/pawl type of latch mechanism and configure the pop-off sound reduction mechanism to interact with the ratchet so as to exert a resistive force on the ratchet arranged to counteract seal loads exerted on the ratchet by the striker. 
     In accordance with these and other aspects, the present disclosure is directed to a closure latch assembly for a closure panel mounted to a motor vehicle for movement between an open position and closed position. The closure latch assembly, comprises: a latch mechanism having a ratchet and a pawl, the ratchet being moveable between a striker release position whereat the ratchet is positioned to retain the striker, the ratchet being biased toward its striker release position, the pawl being moveable between a ratchet releasing position whereat the pawl is positioned to permit the ratchet to move to its striker release position and a ratchet holding position whereat the pawl is positioned to hold the ratchet in its striker capture position, the pawl being biased toward its ratchet holding position; and a pop-off sound reduction mechanism having an auxiliary pawl and a striker lever, the auxiliary pawl being moveable between a ratchet disengaged position whereat the auxiliary pawl is disengaged from the ratchet and a ratchet engaged position whereat the auxiliary pawl is engaged with the ratchet, the auxiliary pawl being biased toward its ratchet engaged position, the striker lever being moveable between a striker disengaged position whereat the auxiliary pawl is held in its ratchet disengaged position and a striker engaged position whereat the auxiliary pawl is permitted to move to its ratchet engaged position, the striker lever being biased toward its striker disengaged position. The striker lever moves from its striker disengaged position into its striker engaged position in response to the striker engaging and moving the ratchet from its striker release position into its striker capture position. A striker exit force exerted on the ratchet by the striker when the ratchet is located in its striker capture position is counteracted by a resistive force exerted on the ratchet and caused by engagement between the ratchet and the auxiliary pawl when the auxiliary pawl is located into its ratchet engaged position in response to movement of the striker lever to its striker engaged position. 
     The latch mechanism associated with the closure latch assembly is operable in a latched state when the pawl is located in its ratchet holding position for holding the ratchet in its striker capture position. The latch mechanism is further operable in an unlatched state when the pawl is moved to its ratchet releasing position for permitting movement of the ratchet to its striker release position. The closure latch assembly further comprising a latch release mechanism for moving the pawl from its ratchet holding position to its ratchet releasing position to shift the latch mechanism from its latched state into its unlatched state. The pop-off sound reduction mechanism is operable in an engaged state when the striker lever is moved by the striker to its striker engaged position and the auxiliary pawl is moved to its ratchet engaged position. The pop-off sound reduction mechanism is also operable in a disengaged state when the striker lever is located in its striker disengaged position and the auxiliary pawl is held in its ratchet disengaged position. 
     When the latch mechanism is in its latched state and the pop-off sound reduction mechanism is in its engaged state, an auxiliary pawl spring acting on the auxiliary pawl applies the resistive force to the ratchet such that subsequent movement of the pawl to its ratchet releasing position acts to shift the latch mechanism into its unlatched mode for causing the ratchet to forcibly move the auxiliary pawl from its ratchet engaged position into its ratchet disengaged position in response to movement of the ratchet toward its striker release position so as to shift the pop-off sound reduction mechanism into its disengaged state. 
     In the closure latch assembly of the present disclosure, the pop-off sound reduction mechanism further includes a memory lever moveable between an auxiliary pawl released position and an auxiliary pawl hold position. The memory lever is biased toward its auxiliary pawl hold position. Movement of the striker lever from its striker disengaged position into its striker engaged position causes the memory lever to move from its auxiliary pawl hold position to its auxiliary pawl released position for permitting the auxiliary pawl to move from its ratchet disengaged position into its ratchet engaged position. Movement of the ratchet from its striker capture position to its striker release position causes the auxiliary pawl to move from its ratchet engaged position to its ratchet disengaged position. The memory lever is operable in its auxiliary pawl hold position to hold the auxiliary pawl in its ratchet disengaged position. 
     In accordance with one embodiment of the present disclosure, the closure latch assembly comprises: a ratchet moveable between a striker release position whereat the ratchet is positioned to receive a striker and a striker capture position whereat the ratchet is positioned to retain the striker; a ratchet spring for biasing the ratchet toward its striker release position; a pawl moveable between a ratchet holding position whereat the pawl is positioned to hold the ratchet in its striker capture position and a ratchet releasing position whereat the pawl is positioned to permit the ratchet to move toward its striker release position; a pawl spring for biasing the pawl toward its ratchet holding position; an auxiliary pawl moveable between a ratchet engaging position whereat a cam surface on the auxiliary pawl engages a ratchet segment of the ratchet and a ratchet disengaging position whereat the cam surface is disengaged from the ratchet segment; an auxiliary pawl spring biasing the auxiliary pawl toward its ratchet engaged position; a memory lever moveable between an auxiliary pawl hold position whereat the memory lever is positioned to hold the auxiliary pawl in its ratchet disengaged position and an auxiliary pawl released position whereat the memory lever permits the auxiliary pawl to move to its ratchet engaged position; a memory lever spring biasing the memory lever toward its auxiliary pawl hold position; a striker lever moveable between a striker disengaged position whereat the striker lever positions the memory lever in its auxiliary pawl hold position and a striker engaged position whereat the striker lever positions the auxiliary pawl in its auxiliary pawl released position; and a striker lever spring biasing the striker lever toward its striker disengaged position. The striker lever moves from its striker disengaged position to its striker engaged position in response to the striker engaging and moving the ratchet from its striker release position into its striker capture position. A striker exit force exerted by the striker on the ratchet when the ratchet is held in its striker capture position is counteracted by a resistive force exerted by the auxiliary pawl spring between the cam surface on the auxiliary pawl and the ratchet segment on the ratchet when the auxiliary pawl is located ratchet engaged position. 
     The closure latch assembly of the present disclosure establishes a latched state between the ratchet and the pawl when the pawl is located in its ratchet holding position for holding the ratchet in its striker capture position, and an unlatched state between the ratchet and the pawl when the pawl is moved to its ratchet releasing position. An engaged state is established between the ratchet and the auxiliary pawl when the ratchet is located in its striker capture position and the auxiliary pawl is located in its ratchet engaging position, and a disengaged state is established between the ratchet and the auxiliary pawl when the ratchet moves a predetermined distance from its striker capture position toward its striker release position which causes the auxiliary pawl to move from its ratchet engaged position to its ratchet disengaged position in opposition to the biasing of the auxiliary pawl spring. The resistive force is applied to the ratchet during the predetermined distance required to shift into the unlatched and disengaged states. The cam surface on the auxiliary pawl has a positive back-out profile configured to generate the resistive force as the auxiliary pawl is moved by the ratchet from its ratchet engaged position to its ratchet disengaged position. 
     In accordance with another embodiment of the present disclosure, there is provided a closure latch assembly for a closure panel mounted to a motor vehicle for movement between an open position and closed position. The closure latch assembly includes a latch mechanism having a ratchet and a pawl, the ratchet being moveable between a striker release position whereat the ratchet is positioned to receive a striker and a striker capture position whereat the ratchet is positioned to retain the striker, the ratchet being biased toward its striker release position, the pawl being moveable between a ratchet releasing position whereat the pawl is positioned to permit the ratchet to move to its striker release position and a ratchet holding position whereat the pawl is positioned to hold the ratchet in its striker capture position, the pawl being biased toward its ratchet holding position. The closure latch assembly also includes a ratchet motion reduction mechanism having an auxiliary pawl being moveable between a ratchet disengaged position whereat the auxiliary pawl is disengaged from the ratchet and a ratchet engaged position whereat the auxiliary pawl is engaged with the ratchet, the auxiliary pawl being biased toward its ratchet engaged position. A striker exit force exerted on the ratchet by the striker when the ratchet is located in its striker capture position is counteracted by a resistive force exerted on the ratchet by the auxiliary pawl as the auxiliary pawl is moved from its ratchet engaged position to its ratchet disengaged position in response to movement of the ratchet from its striker capture position and striker release position. 
     In accordance with another embodiment of the present disclosure, the ratchet includes a ratchet extension segment configured to engage a cam surface on the auxiliary pawl when the ratchet is located in its striker capture position and the auxiliary pawl is located in its ratchet engaged position, wherein the resistive force counteracts a cam-out force of the ratchet extension segment on the cam surface. 
     In accordance with another embodiment of the present disclosure, the auxiliary pawl is rotatable about an auxiliary pawl axis, and wherein the cam surface includes a positive cam-out profile configured to generate a rotation of the auxiliary pawl as the ratchet extension segment engages the cam surface to move the auxiliary pawl from its ratchet engaged position to its ratchet disengaged position. 
     In accordance with another embodiment of the present disclosure, the closure latch assembly further includes an auxiliary pawl spring biasing the auxiliary pawl toward its ratchet engaged position, wherein the resistive force further includes a force exerted by the auxiliary pawl spring opposing the movement of the auxiliary pawl from its ratchet engaged position to its ratchet disengaged position. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations such that the drawings are not intended to limit the scope of the present disclosure. 
         FIG. 1  is a partial isometric view of a motor vehicle having a closure panel equipped with a closure latch assembly that is structurally and functionally configured in accordance with the teachings of the present disclosure to provide a pop-off sound reduction feature. 
         FIGS. 2A through 2E  are a series of sequential views illustrating the movement of various components of a latch mechanism, a snowload mechanism, and a power-operated latch release mechanism associated with the closure latch assembly of the present disclosure during a power latch release operation; 
         FIGS. 3A through 3C  are another series of sequential views for illustrating the interaction between the components of the latch mechanism and the snowload mechanism associated with the closure latch assembly of the present disclosure during the power latch release operation; 
         FIGS. 4A through 4C  are a series of sequential views illustrating the movement of various components of the latch mechanism and a pop-off sound reduction mechanism associated with the closure latch assembly of the present disclosure during the power latch release operation; 
         FIGS. 5A through 5D  are another series of sequential views illustrating the movement of various components of the latch mechanism and the pop-off sound reduction mechanism associated with closure latch assembly of the present disclosure during a latch closing operation; 
         FIG. 6  is another view of the interaction between the components of the latch mechanism and the pop-off sound reduction mechanism associated with the closure latch assembly of the present disclosure during a manual latch reset operation; 
         FIGS. 7 and 8  graphically illustrate various plots of an exit striker velocity characteristic comparing a latch mechanism without the pop-off sound reduction mechanism ( FIG. 7 ) and with the pop-off sound reduction mechanism ( FIG. 8 ) to provide an exemplary comparison showing the improvement provided by the closure latch assembly of the present disclosure; and 
         FIGS. 9 and 10  graphically illustrate various plots of an exit striker acceleration characteristic comparing a latch mechanism without the pop-off sound reduction mechanism ( FIG. 9 ) and with the pop-off sound reduction mechanism ( FIG. 10 ) to provide an exemplary comparison showing the improvement provided by the closure latch assembly of the present disclosure. 
     
    
    
     Corresponding reference numerals indicate corresponding components throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     An example embodiment of a closure latch assembly providing a pop-off sound reduction feature will now be described more fully with reference to the accompanying drawings. To this end, the example embodiment is provided so that this disclosure will be thorough, and will fully convey its intended scope to those who are skilled in the art. Accordingly, numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of the embodiment of the present disclosure. However, it will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms, and that neither should be construed to limit the scope of the present disclosure. In the example embodiment, well-known processes, well-known device structures, and well-known technologies are not described in detail. 
     The terminology used herein is for the purpose of describing a particular example embodiment only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order or sequence of performance. It is also to be understood that additional or alternative steps may be employed. 
     When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Although the terms “first”, “second”, “third”, etc. may be used herein to describe various elements, components, regions, layers, positions and/or sections, these elements, components, regions, layers, positions and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer, position or section from another region, layer, position or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments. 
     Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     In the following detailed description, the expression “closure latch assembly” will be used to generally indicate any manually-actuated or power-operated latch device adapted for use with a vehicle closure panel to provide a noise reducing function with or without a power release feature. Additionally, the expression “closure panel” will be used to indicate any element moveable between an open position and at least one closed position, respectively opening and closing an access opening to an inner compartment of a motor vehicle and therefore includes, without limitations, decklids, tailgates, liftgates, bonnet lids, and sunroofs in addition to the swinging and/or sliding side passenger doors of a motor vehicle to which the following description will make explicit reference, purely by way of example. 
     Referring initially to  FIG. 1  of the drawings, a motor vehicle  10  is shown to include a vehicle body  12  defining an opening  14  providing access to an interior passenger compartment. A closure panel  16  is pivotably mounted to body  12  for movement between an open position (shown) and a fully-closed position to respectively open and close opening  14 . A closure latch assembly  18  is rigidly secured to closure panel  16  adjacent to an edge portion  16 A thereof and is releasably engageable with a striker  20  that is fixedly secured to a recessed edge portion  14 A of opening  14 . As will be detailed, closure latch assembly  18  is operable to engage and releasably retain striker  20  when closure panel  16  is moved to its fully-closed position. An outside handle  22  and an inside handle  24  are provided for actuating closure latch assembly  18  to release striker  20  and permit subsequent movement of closure panel  16  to its open position. An optional lock knob  26  is shown which provides a visual indication of the locked state of closure latch assembly  18  and which may also be operable to mechanically change the locked state of a lock mechanism associated with closure latch assembly  18 . A weather seal  28  is mounted on edge portion  14 A of opening  14  in vehicle body  12  and is adapted to be resiliently compressed upon engagement with a mating sealing surface of closure panel  16  when closure panel  16  is held by closure latch assembly  18  in its fully-closed position so as to provide a sealed interface therebetween which is configured to prevent entry of rain and dirt into the passenger compartment while minimizing audible wind noise. Obviously, weather seal  28  can alternatively be mounted to closure panel  16  and sealed with respect to a mating sealing surface formed on edge portion  14 A of opening  14 . For purpose of clarity and functional association with motor vehicle  10 , closure panel  16  is hereinafter referred to as vehicle door  16 . However, as noted previously, the closure panel can also be a liftgate, tailgate, decklid, or the like, without departing from the scope of the subject disclosure. 
     Referring initially to  FIGS. 2A through 2E , closure latch assembly  18  is generally shown to include, in this non-limiting configuration, a latch housing  30 , a latch mechanism  32 , a power-operated latch release mechanism  34 , a manually-operated latch release mechanism  38 , and a snowload mechanism  36 . Latch housing  30  is configured to be rigidly secured to edge portion  16 A of vehicle door  16  and includes a latch plate  40  and a base plate  102  ( FIG. 3A ) which together define an entry aperture, commonly referred to as fishmouth slot  42 , through which striker  20  travels upon movement of vehicle door  16  toward and away from its closed positions. 
     Latch mechanism  32  is shown, in this non-limiting example, configured as a single ratchet/pawl arrangement having a ratchet  44  and a pawl  46 . Ratchet  44  is mounted via a ratchet pivot pin  48  to latch housing  30  for movement between various distinct positions including a first or “striker release” position, a second or “secondary striker capture” position, and a third of “primary striker capture” position, each better defined hereinafter. A ratchet biasing member, such as a ratchet spring, is schematically shown by arrow  50  and is operable to normally bias ratchet  44  in a striker releasing direction toward its striker release position. Ratchet  44  is configured to include a contoured striker guide slot  52  which terminates in a striker capture pocket  54 , a primary latch tooth  56 , a secondary latch tooth  58 , and a raised cam surface  60 . 
     Pawl  46  of latch mechanism  32  is mounted via a pawl pivot pin  64  to latch housing  30  for movement between various distinct positions including a first or “ratchet releasing” position, a second or “secondary ratchet holding” position, and a third or “primary ratchet holding” position, each better defined hereinafter. A pawl biasing member, such as a pawl spring, is schematically shown by arrow  66  and is operable to normally bias pawl  46  in a ratchet engaging direction toward its primary ratchet holding position. Pawl  46  is configured to include a body segment  68  having a ratchet engaging feature, hereinafter referred to as a pawl latch lug  70 , and first and second upstanding pawl release lugs  72  and  74 . As will be detailed, pawl latch lug  70  engages cam surface  60  on ratchet  44  when ratchet  44  is located in its striker release position and pawl  46  is located in its ratchet releasing position to establish an “unlatched” operating state for latch mechanism  32 . With latch mechanism  32  operating in its unlatched state, vehicle door  16  may be moved to its open position relative to vehicle body  12 . Likewise, pawl latch lug  70  engages secondary latch tooth  58  on ratchet  44  when pawl  46  is located in its secondary ratchet holding position so as to hold ratchet  44  in its secondary striker capture position and establish a “secondary latched” operating state for latch mechanism  32 . With latch mechanism  32  operating in its secondary latched state, vehicle door  16  is latched in a partially-closed (i.e. soft close) position relative to vehicle body  12 . Finally, pawl latch lug  70  engages primary latch tooth  56  on ratchet  44  when pawl  46  is located in its primary ratchet holding position so as to hold ratchet  44  in its primary striker capture position and establish a “primary latched” operating state for latch mechanism  32 . With latch mechanism  32  operating in its primary latched state, vehicle door  16  is latched in its fully-closed (i.e. hard close) position relative to vehicle body  12 . 
     With continued reference to  FIGS. 2A-2E , power-operated latch release mechanism  34  is shown, in this non-limiting example, mounted within latch plate  40  and configured to generally include an electric power release motor  80  having a motor shaft  82 , a reduction gearset  84  driven by motor shaft  82 , and a power release cam  86 , which together define a power release actuator. Reduction gearset  84  includes a worm  88  having threads meshed with teeth formed on a worm gear  90 . Power release cam  86  is a uni-directional arrangement and includes first and second cam lugs  92 A,  92 B formed on and extending outwardly from worm gear  90 . Cam lugs  92 A,  92 B are configured to selectively engage first pawl release lug  72  on pawl  46  to pivot pawl  46  in a ratchet releasing direction (as indicated by arrow  96  in  FIG. 2B ) from its primary ratchet holding position into its ratchet releasing position in response to rotation of reduction gearset  84  in a latch releasing direction (as indicated by arrow  98  in  FIG. 2B ) caused by actuation of the power release actuator to provide a power latch release operation. Thus, the power latch release operation functions to shift latch mechanism  32  from its primary latched operating state into its unlatched operating state. Obviously, the power latch release operation can also be used to shift latch mechanism  32  from its secondary latched state into its unlatched state when door  16  is latched in its partially-closed position. 
     As also shown in  FIGS. 2A-2E , closure latch assembly  18  is equipped with manually-operated latch release mechanism  38  which is configured to move pawl  46 , directly or indirectly, from its primary ratchet holding position (or its secondary ratchet holding position) into its ratchet releasing position for shifting latch mechanism  32  into its unlatched operating state. Manually-operated latch release mechanism  38  is schematically shown to generally include a manually-actuated device  99  interconnected to pawl  46  via a connection mechanism  101 . Manually-actuated device  99  can include any apparatus configured to cause connection mechanism  101  to move pawl  46  to its ratchet releasing position in response to an input action from the user such as, for example, actuation of inside door handle  24  or outside door handle  22  and the like. Connection mechanism  101  is configured to convert the input action exerted by the user on manually-actuated device  99  into a force sufficient to pivot pawl  46  from one of its ratchet holding positions into its ratchet releasing position and may include, for example, cables, linkages, rods and the like. 
       FIG. 2A  shows latch mechanism  32  in its primary latched operating state with pawl  46  located in its primary ratchet holding position such that pawl latch lug  70  engages primary latch tooth  56  on ratchet  44  for mechanically holding ratchet  44  in its primary striker capture position in opposition to the biasing of ratchet spring  50 . In this operating state of latch mechanism  32 , vehicle door  16  is held in its fully-closed position. Note that power release cam  86  is located in a home position with cam lugs  92 A,  92 B displaced from engagement with either of pawl release lugs  72 ,  74 . 
       FIG. 2B  shows initiation of the power latch release operation with rotation of power release gear  90  in its latch releasing direction causing cam lug  92 B to engage first pawl release lug  72  and forcibly pivot pawl  46  in its ratchet releasing direction, in opposition to the biasing of pawl spring  66 , from its primary ratchet holding position toward its ratchet releasing position. 
       FIG. 2C  shows completion of the power latch release operation with pawl  46  located in its ratchet releasing position with cam lug  92 A engaging second pawl release lug  74  while power release cam  86  is located in its stop/home position. As will be detailed in reference to  FIGS. 3A-3C  hereinafter, full travel movement of pawl  46  from its primary ratchet holding position ( FIG. 2A ) to its ratchet releasing position ( FIG. 2C ) results in snowload mechanism  36  shifting from a non-engaged state ( FIGS. 2A and 3A ) into an engaged state ( FIGS. 2C and 3B ) for mechanically holding pawl  46  in its ratchet releasing position. Snowload mechanism  36  is subsequently shifted back into its non-engaged state ( FIGS. 2D and 3C ) in response to movement of ratchet  44  past its secondary striker capture position so as to release pawl  46  for movement toward ratchet  44 . 
       FIG. 2D  shows latch mechanism  32  in its unlatched operating state as snowload mechanism  36  is shifted back to its non-engaged state with pawl latch lug  70  slightly displaced from engagement with cam surface  60  while cam lug  92 A continues to engage second pawl release lug  74 .  FIG. 2E  shows ratchet  44  rotated completely to its striker release position and illustrates pawl latch lug  70  engaging raised cam surface  60  on ratchet  44  while cam lug  92 A has slid along in continued engagement with second pawl release lug  74 . In the positions shown in both  FIGS. 2D and 2E , power release cam  86  is prevented from further rotation in the latch releasing direction. With ratchet  44  located in its striker release position, latch mechanism  32  is operating in its unlatched state for allowing vehicle door  16  to be moved from its fully-closed position to its open position. 
     Referring now to  FIGS. 3A-3C , the functional operation of snowload mechanism  36  will now be described in greater detail. Snowload mechanism  36  generally includes a snowload lever  100  pivotably mounted to base plate  102  of latch housing  30  via a snowload lever pivot pin  104 , and a snowload lever biasing member, such as a snowload lever spring, schematically shown by arrow  106 . Snowload lever  100  includes a latch lug  108  and a release lug  110  and is shown in  FIG. 3A  biased by snowload lever spring  106  toward a first or “pawl engaged” position. Latch mechanism  32  is shown in  FIG. 3A  operating in its primary latched state with latch lug  70  on pawl  46  engaging primary latch tooth  56  on ratchet  44  such that pawl  46  is located in its primary ratchet holding position for holding ratchet  44  in its primary striker capture position. As such, latch lug  108  on snowload lever  100  is disengaged from a latching feature, such as a latch tooth  112 , formed on body segment  68  of pawl  46  such that snowload mechanism  36  is operating in its non-engaged state.  FIG. 3B  illustrates that movement of pawl  46  to its ratchet releasing position results in latch lug  108  on snowload lever  100  being biased into its pawl engaged position for latched engagement with latch tooth  112  on pawl  46 , thereby mechanically holding pawl  46  in its ratchet releasing position so as to establish the engaged operating state of snowload mechanism  36 .  FIG. 3C  illustrates that subsequent rotation of ratchet  44  in its releasing direction causes a release lug  114  on ratchet  44  to engage release lug  110  on snowload lever  100  and forcibly rotate snowload lever  100  from its pawl engaged position into a second or “pawl disengaged” position (as indicated by arrow  118 ), in opposition to the biasing of snowload lever spring  106 , such that latch lug  108  on snowload lever  100  disengages latch tooth  112  on pawl  46 . Release of latch lug  108  from engagement with latch tooth  112  permits pawl spring  66  to urge pawl  46  to rotate back towards its primary ratchet holding position. However, this shifting of snowload mechanism  36  back into its disengaged state only occurs after ratchet  44  has rotated past its secondary striker capture position, thereby assuring no unintended latching of latch mechanism  32  in its secondary latched state. 
     With particular reference now to  FIGS. 4A through 4C , closure latch assembly  18  is further shown to include a pop-off sound reduction (“POSR”) mechanism  120  that is operably associated with latch mechanism  32  and which is configured to exert a resistive load on ratchet  44  arranged to counteract the seal load exerted by striker  20  on ratchet  44  for the purpose of reducing the exit velocity and exit acceleration characteristics of striker  20  as it exits closure latch assembly  18 . The seal load is generated by compression of weather seal  28  when vehicle door  16  is latched in its fully-closed position. This resistive force, which is counteractive against the conventional opening forces, functions to prevent or significantly limit the audible latch “pop-off” sound generated upon initially shifting latch mechanism  32  into its unlatched operating state. In this regard, POSR mechanism  120  can be added to any traditional single ratchet/pawl or double ratchet/pawl latch mechanism configuration and its association with latch mechanism  32  is non-limiting and for purposes of illustration of one such exemplary interactive arrangement. 
     POSR mechanism  120  is generally configured to include an auxiliary pawl  122 , a memory lever  124 , a striker lever  126 , an auxiliary pawl spring  128 , a memory lever spring  130 , and a striker lever spring  132 . 
       FIG. 4A  illustrates latch mechanism  32  in its primary latched state with pawl  46  located in its primary ratchet holding position for holding ratchet  44  in its primary striker capture position. With ratchet  44  held in its primary striker capture position, striker  20  engages an edge portion of striker capture pocket  54  and a striker lug segment  140  of striker lever  126 . In turn, striker lug segment  140  on striker lever  126  is shown in engagement with a resilient overslam bumper  142 . As such, striker lever  126  interfaces between striker  20  and overslam bumper  142 . This interface arrangement provides consistent bumper loads and engagement effort regardless of potential striker misalignment. 
     Striker lever  126  is mounted to latch housing  30  for movement about a striker lever pivot pin  144  (shown in phantom) between a first or “striker engaged” position ( FIG. 4A ) and a second or “striker disengaged” position (FIG.  4 C). Striker lever spring  132  is shown schematically and is arranged to normally bias striker lever  126  toward its striker disengaged position. Auxiliary pawl  122  is mounted to latch housing  30  for movement about an auxiliary pawl pivot post  146  between a first or “ratchet engaged” position ( FIG. 4A ) and a second or “ratchet disengaged” position ( FIG. 4C ). Auxiliary pawl spring  128  is operably arranged to normally bias auxiliary pawl  122  toward its ratchet engaged position. Finally, memory lever  124  is mounted to latch housing  30  for movement about a memory lever pivot post  148  between a first or “auxiliary pawl release” position ( FIG. 5C ) and a second or “auxiliary pawl hold” position ( FIG. 4C ). Memory lever spring  130  acts on memory lever  124  for normally biasing memory lever  124  toward its auxiliary pawl hold position. 
       FIGS. 4A-4C  illustrate a sequential series of views showing movement of the components of POSR mechanism  120  and latch mechanism  32  during a latch release or door opening function during which latch mechanism  32  is shifted from its primary latched state ( FIG. 4A ) into its unlatched state ( FIG. 4C ). Prior to initiation of this door opening function, POSR mechanism  120  is configured to exert the resistive force on ratchet  44  (as indicated by arrow  150  in  FIG. 4B ) which, as noted, is oriented to counteract the seal load (indicated by arrow  152  in  FIG. 4B ) applied to ratchet  44  via striker  20 . In particular, POSR mechanism  120  is shown in  FIG. 4A  in an “engaged” state with a cam surface  156  formed on an outer edge portion of auxiliary pawl  122  engaging a ratchet extension segment  158  formed on ratchet  44  when ratchet  44  is located in its primary striker capture position (held by pawl  46  located in its primary ratchet holding position) and auxiliary pawl  122  is located in its ratchet engaged position. Upon movement of pawl  46  to its ratchet releasing position (via actuation of power-operated latch release mechanism  34  or operation of manually-operated latch release mechanism  38 ), initial rotation of ratchet  44  toward its striker release position ( FIG. 4B ) causes ratchet extension segment  158  to cam against cam surface  156  on auxiliary pawl  122  and forcibly pivot auxiliary pawl  122  about its pivot post  146  from its ratchet engaged position toward its ratchet disengaged position, in opposition to the biasing exerted thereon by auxiliary pawl spring  128 . Cam surface  156  is configured to include a “positive back-out” contour or profile providing a limited amount of continuous engagement with ratchet extension segment  158  of ratchet  44  during a predetermined amount of striker travel (indicated by dimension “x” in  FIG. 4B ). This positive back-out profile feature is designed so that a portion of seal load  152  conventionally used to accelerate striker  20  out of ratchet  44  is now used to pivot auxiliary pawl  122  out of engagement with ratchet  44  in the form of resistive force  150 . As a result, the exit acceleration and velocity characteristics of striker  20  upon release of latch mechanism  32  are significantly reduced by POSR mechanism  120 . Resistive force  150  is exerted on ratchet  44  for the predetermined striker travel “x” during which the seal loads associated with compressed weather seal  28  ( FIG. 1 ) are the highest. In a non-limiting example, the striker distance “x” can be in a range of 1.5-3.5 mm of travel and, more preferably, is about 2.2 mm. However, other predetermined amounts of striker travel “x” (associated with an initial amount of rotation of ratchet  44 ) can be utilized without departing from the scope of the subject disclosure. 
     Prior to disengagement of ratchet extension segment  158  from cam surface  156 , the interaction therebetween functions to move auxiliary pawl  122  to its ratchet disengaged position whereat a latch tooth  160  formed on a leg segment  162  of memory lever  124  engages a latch lug segment  164  formed on auxiliary pawl  122 , as is best shown in  FIG. 4C . Thus, memory lever  124  is operable in its auxiliary pawl hold position to mechanically hold auxiliary pawl  122  in its ratchet disengaged position.  FIG. 4C  illustrates ratchet  44  located in its striker release position, pawl  46  located in its ratchet releasing position, striker lever  126  located in its striker disengaged position, memory lever  124  located in its auxiliary pawl hold position, and auxiliary pawl  122  located in its ratchet disengaged position upon completion of the latch opening function and as vehicle door  16  is moved toward its open position. 
       FIGS. 5A through 5D  illustrate a sequential series of views showing movement of the components of POSR mechanism  120  and latch mechanism  32  during a latch closing function caused in response to vehicle door  16  moving into its fully-closed position and which results in shifting of latch mechanism  32  into its primary latched state and shifting of POSR mechanism  120  into its engaged state. In particular,  FIG. 5A  illustrates striker  20  engaging and forcibly rotating ratchet  44  in a latching direction due to engagement of striker  20  with striker guide slot  52  as ratchet  44  approaches its primary striker capture position.  FIG. 5B  illustrates that continued rotation of ratchet  44  in its latching direction results in striker  20  engaging striker lever  126  and causing striker lever  126  to pivot about its pivot pin  144  and move from its striker disengaged position into its striker engaged position, as indicated by arrow  170 . Such movement of striker lever  126  causes a striker lever lug  172  formed thereon to engage a memory lever lug  174  formed on memory lever  124 , thereby forcibly rotating memory lever  124  from its auxiliary pawl holding position toward its auxiliary pawl released position, as indicated by arrow  176 .  FIG. 5C  illustrates that such movement of memory lever  124  results in latch tooth  160  on leg segment  162  of memory lever  124  disengaging latch lug segment  164  on auxiliary pawl  122 , thereby allowing auxiliary pawl spring  128  to forcibly move auxiliary pawl  122  from its ratchet disengaged position ( FIG. 5B ) toward its ratchet engaged position, as indicated by arrow  178 . As seen, cam surface  156  of auxiliary pawl  122  is now engaged with ratchet extension  158  on ratchet  44 . Finally,  FIG. 5D  illustrates ratchet  44  located in its primary striker capture position, pawl  46  located in its primary ratchet holding position, striker lever  126  located in its striker engaged position, memory lever  124  located in its auxiliary pawl released position, and auxiliary pawl  122  located in its ratchet engaged position. As such, latch mechanism  32  is now operating it its primary latched state and POSR mechanism  120  is now operating in its engaged state upon completion of the latch closing function. 
       FIG. 6  illustrates the situation where ratchet  44  is moved to its primary striker capture position (or secondary striker capture position) without engagement with striker  20 , such as possibly during a service action or unintended release of latch mechanism  32 . As seen, POSR mechanism  120  remains in its disengaged state with striker lever  126  located in its striker released position, memory lever  124  located in its auxiliary pawl hold position, and auxiliary pawl  122  located in its ratchet disengaged position. As such, the resistive load of POSR mechanism  120  is not exerted on ratchet  44  so as to allow latch mechanism  32  to be unlatched normally. 
       FIG. 7  is an example plot of striker exit velocities at different levels (%) of seal loads measured against time for a conventional latch mechanism without POSR mechanism  120 . In comparison,  FIG. 8  is a similar example plot of striker exit velocities for closure latch assembly  18  having POSR mechanism  120 . As is evident, POSR mechanism  120  provides a significant reduction (approximately 27%) in the striker exit velocity which is equivalent to a reduction of about 200 N in the seal load.  FIGS. 9 and 10  provide a similar example comparison of striker acceleration characteristic for a closure latch assembly without a POSR mechanism ( FIG. 9 ) and closure latch assembly  18  with POSR mechanism  120  ( FIG. 10 ) illustrating a significant reduction (approximately 40%) in the striker exit acceleration which is equivalent to a seal load reduction of about 300 N. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.