Diverter valve and pressure regulator assembly

Abstract

In a system for delivering air from an air pump to an internal combustion engine exhaust system, a diverter valve and pressure regulator assembly also supplies air to an auxiliary pneumatic device. A diverter valve member is shifted when necessary to recharge the auxiliary device to maintain a predetermined minimum pressure and also during engine deceleration to interrupt air flow to the exhaust system and thus preclude exhaust backfiring.

Description

This invention relates to a diverter valve and pressure regulator assembly for use in a system which delivers air from an air pump both to the exhaust system of an internal combustion engine and to an auxiliary pneumatic device, and more particularly, to an assembly having pressure regulating means which operate diverter valve means to charge the auxiliary pneumatic device.

Known diverter valve units, such as that set forth in U.S. Ser. No. 301,619 filed Oct. 27, 1972 and now U.S. Pat. No. 3,835,646, include anti-backfire and pressure relief provisions. In those units, a diaphragm is actuated by a sudden decrease in manifold pressure to shift a diverter valve member for a selected period during deceleration; in its shifted position, the valve member diverts the entire air flow away from the exhaust system to preclude exhaust backfiring and instead directs the air flow either to the engine induction system air cleaner or through a separate silencer. In addition, that diverter valve unit has a pressure relief valve member which permits a portion of the air flow to divert away from the exhaust system and escape to the air cleaner or through the silencer when the air pump discharge pressure exceeds a certain value.

This invention provides an improved diverter valve and pressure regulator assembly which, in addition to the functions of the known units, also supplies and regulates the pressure of air for an auxiliary pneumatic device.

In a diverter valve and pressure regulator assembly provided by this invention, an actuating diaphragm positions a diverter valve member in response to variations in the pressure of the air supplied to the auxiliary pneumatic device. If such pressure drops below a predetermined minimum value, the diverter valve member is shifted to interrupt flow from the air pump to the engine exhaust system until the auxiliary device is recharged. In addition, a control diaphragm responds to the abrupt increase in induction manifold vacuum which occurs upon engine deceleration and opens a control valve which equalizes the pressures across the actuating diaphragm; while this occurs, the actuating diaphragm again shifts the diverter valve member to interrupt air flow to the exhaust system to preclude exhaust backfiring.

The details as well as other features and advantages of this invention are set forth in the detailed description below and are shown in the drawing in which:

FIG. 1 is a schematic view of an internal combustion engine having an air pump for delivering air to the exhaust system and showing this diverter valve and pressure regulator assembly in an enlarged sectional elevational view; and

FIG. 2 is a view indicated by the line 2--2 in FIG. 1 further enlarged to show a check valve used as a portion of the anti-backfire mechanism.

Referring to the drawing, an internal combustion engine 10 drives an air pump 12 which supplies air through a conduit 14, a diverter valve and pressure regulator assembly 16, and a second conduit 18 to the exhaust manifold 20 or other portion of the exhaust system 22. As is well known, air supplied in this manner supports combustion of exhaust gas hydrocarbonns and carbon monoxide and reduces emission of those constituents to the atmosphere.

Assembly 16 includes an upper housing 24 having a lateral inlet 26 receiving air from conduit 14 and opening to a valve chamber 28. Housing 24 also has a main outlet 30 opening from valve chamber 28 for discharging air to conduit 18. A diverter valve member 32 is disposed in valve chamber 28 and has a valve surface 34 engageable with a valve seat 36 surrounding main outlet 30.

Housing 24 also has a diversion outlet 38 opening from valve chamber 28 to a conduit 40 which may extend to an engine induction air cleaner 42 secured above a carburetor 44. A pressure relief valve member 46 is biased by a spring 48 to engage a valve seat 50 surrounding diversion outlet 38. Spring 48 allows relief valve 46 to move away from seat 50 and permit air flow to air cleaner 42 or another silencer whenever the pump discharge pressure in valve chamber 28 exceeds a certain level. This can occur when diverter valve member 32 engages seat 36 or when the engine and pump are operating at high speeds.

Diverter valve member 32 is secured to the upper end of a hollow stem 52. Adjacent its lower end, stem 52 extends through a backing plate 54, a ring spacer 56, a flexible check valve 58, a dished plate 60, an actuating diaphragm 62, and a retainer plate 64. The bottom 66 of stem 52 is spun outwardly over plate 64 and is closed by a plug 68.

A fiberglass-reinforced nylon insert 70 has a lower rim 72 secured between upper housing 24 and a lower housing 74, diaphragm 62 being retained between insert 70 and lower housing 74. Insert 70 also has an upper rim 76 pressed into a bore 78 of upper housing 24 -- a deep groove 80 in rim 78 facilitating the press fit.

Insert 70 additionally has a guide portion 82 which supports and guides stem 52. A regulated pressure chamber 84 is defined between diaphragm 62 and insert 70, and a lip seal 86 surrounds stem 52 to prevent air leaks between chambers 28 and 84.

Insert 70 further has a fitting 88 connected through a conduit 90 to a reservoir 92. A valve 94 controls the flow of air from reservoir 92 to a pneumatic motor 96 in any desired manner.

In operation, pump 12 delivers air through conduit 14 and inlet 26 to valve chamber 28 where it enters lateral holes 98 in diverter valve member 32 and stem 52 and passes down through a passage 100 defined in stem 52, through openings 101 at the bottom of stem 52 into a chamber 102 defined by dished plate 60, and upwardly through a plurality of openings 104 in dished plate 60 into regulated pressure chamber 84. When chamber 84 and reservoir 92 are charged to a predetermined minimum pressure, diaphragm 62 is lowered against the bias of a spring 105 to lower stem 52 and thus valve member 32 until it engages a stop defined by the upper surface 106 of guide portion 82. As the pump discharge pressure in valve chamber 28 and in chamber 102 drops below the pressure in chamber 84, the outer rim of check valve 58 flexes downwardly and engages over openings 104 to prevent back flow of air from reservoir 92. As the pressure in reservoir 92 and chamber 84 drops below the predetermined minimum value, spring 105 raises stem 52 to again engage valve member 32 with valve seat 36, thus directing air flow through valve stem passage 100 to recharge chamber 84 and reservoir 92. Reservoir 92 thus may be maintained at a predetermined minimum pressure of, for example, 3 psi. It will be appreciated, of course, that pressure relief valve 46 does not open until a higher pump discharge pressure of, perhaps, 10 psi is reached.

A cup 108 is welded to lower housing 74 to define a control chamber 110. A passage 112 leads through lower housing 74 from regulated pressure chamber 84 to control chamber 110, and a passage 114 leads through lower housing 74 from control chamber 110 to a bias chamber 116 defined between diaphragm 62 and lower housing 74.

A control valve disc 118, backed by a washer 120, overlies the entrance 122 to passage 114 from control chamber 110. Valve disc 118 and washer 120 are secured to a stem 124 which extends through a guide 126 formed by lower housing 74. Stem 124 is secured to a control diaphragm 128.

A vacuum chamber 130, defined between diaphragm 128 and lower housing 74, is subjected to the vacuum in the engine induction manifold 132, downstream of the carburetor throttle 134, by a conduit 136 and a fitting 138. A spring 140, disposed in vacuum chamber 130, biases stem 124 and valve disc 118 to the position shown.

During engine deceleration, manifold vacuum rises abruptly, and the vacuum in chamber 130 increases to raise diaphragm 128 and stem 124 and lift valve disc 118 away from entrance 122. Air is then admitted from regulated pressure chamber through passage 112, control chamber 110, and passage 114 to bias chamber 116. Bias chamber 116 has only a restricted outlet through a small aperture 144 formed in lower housing 74, and the air admitted to bias chamber 116 from regulated pressure chamber 84 thus equalizes the pressures across diaphragm 62. Spring 105 thereupon raises stem 52 to engage valve member 32 with valve seat 36, thus preventing air flow to the exhaust system to preclude exhaust backfiring. At such time, or as soon as chamber 84 and reservoir 92 are recharged, the entire air flow is diverted through outlet 50 past relief valve member 46.

Valve stem 124 has a passage 146 to connect vacuum chamber 130 with a timing chamber 148 defined between control diaphragm 128 and a lower cup 150. A flap-type check valve 152 is disposed in passage 146 to regulate flow from chamber 148 to chamber 130.

The details of check valve 152 are shown most clearly in FIG. 2. A washer member 154 is disposed under diaphragm 128 and has a plurality of apertures 156 which receive legs 158 formed on the lower portion of stem 124. Four of these legs are riveted, as at 160, to retain washer 154.

The outer rim 162 of check valve member 152 is supported by the inner rim 164 of washer 154. A central flap 166 of check valve 152 overlies an annular valve seat 168 formed at the base of stem 124. A notch 170 is coined in seat 168. During the period when manifold vacuum in vacuum chamber 130 is increasing, flow from chamber 148 through passage 146 to chamber 130 is restricted to pass through notch 170. Thus, the volume of chamber 148 and the size of notch 170 determine the time required for the pressure in chamber 148 to be reduced to the point where spring 140 will lower diaphragm 128, stem 124 and valve disc 118 to the position shown. During a period of increasing pressure in chamber 130, central flap 166 will be pushed downwardly to allow unrestricted flow from chamber 130 through passage 146 to chamber 148 and thus permit immediate return of diaphragm 128, stem 124 and valve disc 118 to the position shown.

When valve disc 118 returns to the position shown, flow from regulated pressure chamber 84 to bias chamber 116 is interrupted, the pressure in bias chamber 116 bleeds down to atmospheric through aperture 144, and the higher pressure in regulated pressure chamber 84 lowers diaphragm 62 and stem 52 to move diverter valve member 32 away from seat 36 and re-establish air flow through outlet 30 to the exhaust system.

It will be appreciated, therefor, that this diverter valve and pressure regulator assembly supplies and regulates the pressure of air for an auxiliary pneumatic device in addition to controlling the air flow to the engine exhaust system in the desired manner.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A diverter valve and pressure regulator assembly for use on an internal combustion engine having an exhaust system, an air pump, and an auxiliary pneumatic device, said assembly comprising a housing having an inlet adapted to receive air from said pump, an outlet adapted to discharge air to said exhaust system, and a valve seat intermediate said inlet and said outlet, a diverter valve member associated with said valve seat, a spring biasing said diverter valve member toward said valve seat to restrict air flow from said inlet to said outlet, and a diaphragm secured to said housing to define a regulated pressure chamber therebetween, a passage extending from said inlet to said chamber to supply air thereto, said chamber being adapted for connection to said device to supply air thereto, said diaphragm being connected to said diverter valve member and responsive to the pressure in said regulated pressure chamber to shift said diverter valve member away from said valve seat against the bias of said spring when the pressure in said chamber exceeds a predetermined minimum and to permit said spring to shift said diverter valve member toward said valve seat when the pressure in said chamber drops below said minimum whereby air flow through said outlet is restricted to charge said regulated pressure chamber and said device to said minimum pressure, and which further comprises means responsive to engine operating conditions for equalizing the pressures across said actuating diaphragm to permit said spring to shift said diverter valve member toward said valve seat whereby air flow through said outlet to said exhaust system is restricted.

2. A diverter valve and pressure regulator assembly for use on an internal combustion engine having an exhaust system, an air pump, and an auxiliary pneumatic device, said assembly comprising an upper housing having an inlet adapted to receive air from said pump, an outlet adapted to discharge air to said exhaust system, and a valve seat intermediate said inlet and said outlet, a diverter valve member biased into engagement with said valve seat, a stem secured to said valve member, a diaphragm secured to said stem and defining a regulated pressure chamber with said housing, said stem having a passage connecting said inlet and said chamber for supplying air thereto, said chamber being adapted for connection to said device for supplying air thereto, a check valve in said passage for preventing air flow from said chamber to said inlet, said diaphragm being responsive to the pressure in said regulated pressure chamber to shift said diverter valve member away from said valve seat when the pressure in said chamber exceeds a predetermined minimum and to permit said diverter valve member to engage said valve seat when the pressure in said chamber is below said minimum whereby air flow through said outlet is restricted to charge said regulated pressure chamber and said device to said minimum pressure, a lower housing defining a bias chamber with said actuating diaphragm, said lower housing having a restricted aperture opening from said bias chamber and a passage connecting said regulated pressure chamber and said bias chamber, a control valve in said housing passage biased to prevent flow from said regulated pressure chamber to said bias chamber, and means for operating said control valve to permit flow from said regulated pressure chamber to said bias chamber and thereby equalize the pressures therein to permit said diverter valve to engage said valve seat and thus restrict flow to the engine exhaust system.