Abstract:
A check valve which is positioned in the vacuum air line of an internal combustion engine. The check valve includes a single-piece valve body having an outlet port and two or more inlet ports, with one outlet port located substantially in line with the inlet port and connected by a venturi tube. The second inlet port is separated from the main air flow line by the valve stem and a diaphragm which allows communication there between and prevents back pressure. The second inlet port communicates with the outlet port through the valve stem and a second venturi tube which provides a vacuum boost to a device, usually vehicle brakes, connected to the inlet.

Description:
FIELD OF THE INVENTION 
     This invention relates to valves, and will have special application to check valves used in internal combustion engines. 
     BACKGROUND OF THE INVENTION 
     Internal combustion engines have long employed air flow conduits to provide vacuum assist for automobile subsystems, such as brakes, automatic transmissions and others. These systems often employed chick valves located along the air flow conduit to prevent subsystem back pressure from reaching the engine. A typical check valve of this sort is described in U.S. Pat. No. 3,889,710. 
     Prior check valves employed either a continuous diameter airway or employed multiple valves and hoses to create a venturi effect and act as a vacuum booster for the subsystem to which it was associated. Space limitations in the automobile engine compartment all but preclude the use of multiple valve-hose system, while the prior art continuous diameter airways did not provide the increased power boost desired to implement the brakes or other subsystem. 
     SUMMARY OF THE INVENTION 
     This invention provides for a space-saving vacuum booster check valve located along a conduit between the air intake manifold and the brake booster. The check valve includes three or more ports connected by hoses to the air intake, block, and one or more vehicle subsystems. Venturi tubes in the valve body connect the various ports to provide a vacuum booster effect to the subsystem. A common concave valve seat and diaphragm serve to prevent back pressure from the subsystem from entering the main conduit between the air intake and the engine block. 
     Accordingly, it is an object of this invention to provide for a novel and improved check valve assembly. 
     Another object is to provide a check valve for an internal combustion engine which acts as a vacuum booster for vacuum assisted subsystems. 
     Another object is to provide a check valve for an internal combustion engine which is efficient, economical, durable, and still meets the minimal size specifications of an automobile engine compartment. 
     Other objects will become apparent upon a reading of the following description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred embodiment of the invention has been depicted for illustrative purposes only wherein: 
     FIG. 1 is a plan view of the check valve of this invention. 
     FIG. 2 is a cross-sectional view taken along line  2 — 2  of FIG.  1 . 
     FIG. 3 is a plan view of the lower valve port. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The preferred embodiment of the invention herein described is not intended to be exhaustive or to limit the invention to the precise form disclosed. It is chosen and described to explain the principles of the invention, and its application and practical use to enable others skilled in the art to follow its-teachings. 
     Referring now to the drawings, reference numeral  10  refers generally to the check valve of this invention. Check valve  10  is normally employed in an internal combustion engine in the air flow line between the engine block and the air intake port at the full mixing port, normally a carburetor or fuel injection port. For clarity, the engine, carburetor, hose connections, and subsystems are not shown, and it is understood that these ports are common to the internal combustion engines found in almost all vehicles. 
     The air flow system in the typical internal combustion engine operates on the principle that as the engine operates, a partial vacuum is created which pulls air through the air intake port of the carburetor of fuel injector to aid in proper fuel combustion. This vacuum has been found to be useful in supplementing vacuum assist subsystems in the vehicle, particularly brakes, automatic transmissions and most recently, air conditioners. Check valve  10  provides the connection between the main airway and the subsystem and serves to inhibit back pressure from the subsystem from disturbing airflow through the main airway. 
     Check valve  10  shown in the drawings include a substantially one piece valve body  12  which is preferably formed of a top valve half  14  and a bottom valve half  16 . The designations of top and bottom halves are for descriptive purposes only and are not limitative of the orientation of valve  10  in the engine compartment. Preferably, top valve half  14  is joined to bottom valve half  16  by sonic welding, heating or other conventional method prior to its use. 
     Bottom valve half  16  includes an air inlet  18  and an air outlet  20  which are in direct air flow communication via air passageway  22 . In typical use in an internal combustion engine, air inlet  18  will be connected via a conduit (not shown) to the air intake port in the engine carburetor or other fuel injection member (not shown). Air outlet  20  is preferably connected via a conduit (not shown) to the vacuum port of the engine block (not shown). 
     As shown, bottom valve half  16  also includes lower valve seats  24 ,  26 . Each lower valve seat  24 ,  26  is defined by a continuous outer wall  28 ,  29 , and a bottom wall  30 ,  31 . A bore  32 ,  33  is defined in each lower valve seat  24 ,  26  to allow for air flow communication with air passageway  22 . Each outer wall  28 ,  29  may include stepped portion  58 ,  59  as shown to provide for ease in mating with upper valve seats  25 ,  27 , as described later in this specification. A plurality of radially spaced fingers  34 ,  35  extend integrally upwardly from each bottom wall  30 ,  31  and serve to support a flexible seal member  36 ,  37 . Air passageway  22  has an opening  38  which allows for air communication between the passageway and valve seat  24 . 
     As shown in FIG. 2, air passageway  22  is defined by a tapering outer passage  40  which narrows from inlet port  18  up to the opening  38 , and a widening passage  42  from opening  38  to the intersection of passageway  22  and valve seat  26 . This configuration of passageway  22  is commonly known as a venturi conduit, whose functions are well known to those skilled in the art. 
     Upper valve half  14  is adopted to mate with lower valve half  14  to form check valve  10 . Upper valve half  14  as shown includes inlet  44  and inlet  46  which may be connected in air flow communication by air passageway  48 . In a typical connection to an internal combustion engine, inlet  44  will be connected via an air hose (not shown) to a brake system (not shown) and inlet  46  will be either capped or connected to another subsystem of a vehicle, such as the air conditioner compressor (not shown). 
     As shown, upper valve half  14  includes valve seats  25 ,  27 . Each upper valve seat  25 ,  27  is defined by continuous outer wall  50 ,  51  and bottom wall  52 ,  53 . A bore  54 ,  55  is defined in each upper valve seat  25 ,  27  to allow for air communication with air passageway  48  and inlets  44 ,  46 . Bottom walls  52 ,  53  are preferably of a smooth concave configuration as shown with bores  54 ,  55  of a slightly lesser diameter than that of seals  36 ,  37 . Each outer wall  50 ,  51  preferably has a circumferential groove  56 ,  57  substantially complemental to the stepped portion  58 ,  59  of the lower valve seats  24 ,  26 . 
     Check valve  10  is assembled by aligning valve seats  24 ,  26  with valve seats  25 ,  27  such that stepped portions  58 ,  59  are aligned with grooves  56 ,  57 . Seals  36 ,  37  are placed on fingers  34 ,  35 , and the valve parts  14 ,  16  are then pressed together and joined as by sonic welding or other common method. The preferred method of joining valve parts  14 ,  16  will generally depend on the material used to form the valve parts, in this embodiment an injection molded heat resistant, rigid plastic. It is understood that an suitable plastic or metal or other compound may be used in forming check valve  10 , which is now ready for implementation in the internal combustion engine as follows. 
     With the above hose hook-ups mentioned above, check valve  10  functions as follows. As the engine (not shown) operates, it draws air through inlet  18 , passageway  22  and outlet  20 . This creates a partial vacuum in valve seats  24 - 27  and passageway  48  to draw seals  36 ,  37  downward against fingers  34 ,  35 . Due to the spacing of fingers  34 ,  35  (FIG. 3) free air flow from passageway  48  to passageway  22  is allowed. The partial vacuum created by the operation of the engine serves in the vacuum assistance of the operation of the brake, and, if desired, air conditioning subsystems (not shown) in a common manner. 
     If for any reason, back pressure in one of the subsystems is generated to create a positive air flow through passageway  48  to inlets  44 ,  46  a reverse flow vacuum is generated to draw seals  36 ,  37  tight against valve seat bottom walls  52 ,  53  to prevent the vacuum from interfering with the above described air flow through passageway  22 . The functioning of check valve  10  as thus far described is well-known to those skilled in the art. 
     As shown in FIG. 2 of the present invention, the tapering and widening passageways,  40 ,  42  create the novel venturi effect on the partial vacuum generated during the operation of the engine (not shown). By their configurations, passageways  40 ,  42  allow for a marked increase in the velocity with reduced pressure of the air passing through passageway  42 . Due to the connection of passageway  22  and valve seats  24 ,  25 , a marked increase in the amount of air drawn through passageway  48  and valve seats  25 ,  24  provides a significant boost in the vacuum assist for the subsystems (not shown) As an example, check valve  10  was tested in a conventional internal combustion engine which normally pulls a vacuum of about seven inches of mercury (7″ Hg). The observed vacuum at outlet  44  with valve  10  in place was eighteen inches of mercury (18″ Hg) which amounts to a 157% increase generated due to the use of valve  10  with its venturi effect passageways  40 ,  42 . 
     It is understood that the above description does not limit the invention to the precise details disclosed, but may be modified within the scope of the following claims.