Composite Valve

The present invention relates to a valve and, more particularly, to a composite valve including a plurality of valve means incorporated as an integral structure therein.

It is often desired to combine a plurality of valves which operate in relation to each other into a single composite valve. By providing such a composite valve, piping between a plurality of separate valves may be omitted and an entirely compact fluid control means is available. A composite valve is particularly effective as a control means to be incorporated in the secondary air supply system for supplying secondary air to the exhaust system of an engine for the purpose of purifying exhaust gases.

When several valves are combined into a composite valve, the design of the exact structure of the composite valve is of course determined in accordance with the particular requirements with regard to the composite valve. However, as a general structure, conventional composite valves have been designed so as to have a housing which is a unitary member or an assembly of several parts and incorporates therein several ports, valve seats, and internal passages required, to which various valve elements and valve actuating means such as diaphragms are individually assembled. In most cases the housings of conventional composite valves are of complicated three-dimensional designs which require complicated manufacturing processes, and, furthermore, they require a large amount of work for assembling individual valves and valve actuating means such as diaphragms into the housings, thereby naturally increasing their cost.

It is therefore the object of the present invention to provide a novel composite valve having a simple structure which is easy in design, manufacture, and assembly.

In accordance with the present invention, the above-mentioned object is accomplished by a composite valve comprising a first dish-like member having an open face and concaved portions which define a plurality of diaphragm chambers, a second dish-like member having an open face and concaved portions which define complex passages, an intermediate member having opposite open faces adapted to join said open faces of said first and second dish-like members and complex partitions which define bearing portions and complex passages, a diaphragm element interposed between said open faces of said first dish-like member and said intermediate member, a plurality of valve elements having stem portions mounted in said bearing portions and stem end portions connected to said diaphragm element, and seat elements interposed between said open faces of said second dish-like member and said intermediate member and providing valve seats which co-operate with said valve elements.

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only and thus are not limitative of the present invention and wherein:

FIG. 1 is a plan view of an embodiment of the composite valve according to the present invention;

FIG. 2 is a side view of the composite valve shown in FIG. 1;

FIGS. 3-7 are sectional views along lines III--III, IV--IV, V--V, VI--VI and VII--VII in FIG. 1, respectively; and

FIG. 8 is a diagram showing the operation system of the composite valve shown in FIGS. 1-7.

Referring to the drawings, the composite valve herein shown is particularly designed as a control valve for a secondary air supply system for purifying exhaust gases of an engine. In these figures, 1 designates a first dish-like member having an open face and concaved portions which define a plurality of diaphragm chambers. In this embodiment the composite valve is designed so as integrally to include five valve means A, B, C, D, and E, and therefore the first dish-like member 1 has five concaved portions designated by 1a, 1b, 1c, 1d, and 1e for the valve means A-E.

Reference numeral 2 designates a second dish-like member which also has an open face and concaved portions, wherein the concaved portions are adapted to define complex passages. The concaved portions are designated by reference numerals 2a, 2b, 2c, 2d, and 2e. Between the first and the second dish-like members is provided an intermediate member 3 having opposite open faces adapted to join said open faces of said first and second dish-like members and complex partitions which define bearing portions 3a, 3b, 3c, 3d, and 3e, and complex passages designated by 3f, 3g, 3h, 3i, 3j, etc..

A diaphragm element 4 is interposed between the opposite open faces of the first dish-like member 1 and the intermediate member 3. In the shown embodiment, the diaphragm element 4 is formed as a unitary element which provides diaphragm elements for all diaphragm means for operating valve means A-E, i.e., it includes diaphragm portions 4a, 4b, 4c, 4d, and 4e corresponding to valve means A-E. In the bearing portions 3a, 3b, 3c, and 3e are individually slidably mounted shaft portions of valve elements 5a, 5b, 5c, and 5e. End portions of these valve elements are individually connected to the diaphragm portions 4a, 4b, 4c, and 4e of the diaphragm element 4. At individual diaphragm portions 4a-4e, disk elements 6a, 7a, 6b, 7b, 6c, 7c, and 6e, 7e are mounted on the opposite sides thereof and are fastened together with the diaphragm element by means of the end portions of the valve elements which penetrate therethrough and nuts 8a, 8b, 8c, and 8e screwed onto the shaft end portions of the valve elements, thereby establishing actuating connection between the individual diaphragm portions and the valve elements. In the case of the valve means D, the disk portion of a valve element 5d is directly mounted on the one side of the diaphragm portion 4d in a manner that a stub shaft portion provided at a central portion of the valve disk portion is penetrated through the diaphragm portion 4d and a disk element 6d provided on the other side thereof and the end portion of the stub shaft portion is enlarged by plastic deformation so as to fasten the integral connection of the valve element 5d, the diaphragm portion 4d and the disk element 6d. The diaphragm portions 4a-4e are exerted with biasing force by compression coil springs 9a, 9b, 9c, 9d, and 9e, respectively.

Between the opposing end faces of the second dish-like member 2 and the intermediate member 3 are interposed valve seat elements 10a, 10b, 10c, and 10e providing valve seats which co-operate with valve elements 5a, 5b, 5c, and 5e. For valve element 5d, a portion of the intermediate member 3 directly provides a valve seat 10d.

The intermediate member 3 has a port 11 formed at a portion thereof, in which is mounted a stub tube element 12. The port 11 communicates to the passage 3f. The second dish-like member 2 is formed with ports 13 and 14 in which are individually mounted stub tube elements 15 and 16. The port 13 communicates to the passage 2a, while the port 14 communicates to the passage 2b.

Along the joining surfaces of the diaphragm element 4 and the intermediate member 3, corresponding to diaphragm portions 4a-4e, annular sealing elements 17a, 17b, 17c, 17d, and 17e are provided. Furthermore, although it is not shown in the figure, any proper sealing means such as a gasket may be provided along the joining surfaces of the diaphragm element 4 and the first dish-like member 1 and of the second dish-like member 2 and the intermediate member 3. The first and second dish-like members 1 and 2 and the intermediate member 3 interposed therebetween are, as best shown in FIG. 2, clamped together by a number of bolts 18.

In the composite valve thus assembled, the concaved portions 1a-1c provide diaphragm chambers which are supplied with control fluid pressure through plug port means (not shown in the figure) mounted to penetrate the wall portions of the first dish-like member 1, said control fluid pressure controlling displacement of individual diaphragm portions 4a-4c thereby controlling operation of the individual valve means A-C. Similarly, a plug port means (not shown) is mounted to a wall portion of the intermediate member to provide a connection of control fluid pressure to a chamber 3k.

FIG. 8 is an operational diagram for the composite valve shown in FIGS. 1-7. In this case, the composite valve is adapted to operate as a control valve in a secondary air supply system for supplying secondary air to the exhaust system of an engine. In this case, the port 11 is supplied with secondary air delivered from an air pump, while the air delivered to the port 13 is conducted to an air injection port of the secondary air supply system. The port 14 serves to discharge excess air and is connected to an air cleaner of the engine so as to discharge the excess air into the air cleaner. The valve means A and B are air control valves ACV.sub.1 and ACV.sub.2 which are adapted to be oppositely operated in synchronization with each other by control vacuum supplied through vacuum control valve VCV.sub.1 and vacuum switching valves VSV.sub.1 and VSV.sub.2 so as to supply a controlled portion of the air supplied from the air pump to the air injection port through ACV.sub.1 while discharging the remaining portion toward the air cleaner through ACV.sub.2 . This changing-over operation is explained as follows, if referred to FIGS. 1-7: The air supplied through the port 11 is introduced into the passage 3f, wherefrom the air flows to the passage 2a if the valve element 5a is opened, thereby delivering air through the port 13. On the other hand, if the valve element 5b is opened, the air introduced into the passage 3f flows into the passage 2b, wherefrom it is discharged through the port 14 toward the air cleaner.

The valve means C provides a relief bypass valve RBV. This valve is controlled by vacuum supplied to the diaphragm chamber 1c through the vacuum control valve VCV.sub.2 and the vacuum switching valve VSV.sub.2 and operates so as to release the air supplied through the port 11 towards the air cleaner when it opens. Referring to FIGS. 1-7 in this connection, the air supplied to the passage 3f through the port 11 further flows through the passage 3g to the passage 3h, wherefrom it flows into the passage 2c if the valve element 5c is opened, so as to be discharged through the passage 2b and the port 14.

The valve means D provides a relief valve RV which protects the air pump from overloading. In more detail, if the delivery pressure of the air pump has risen beyond a predetermined value, this valve opens so as to release the air supplied through the port 11 towards the air cleaner through the port 14. Referring to FIGS. 1-7 in this connection, the air introduced into the passage 3f through the port 11 flows to the passage 2d, and if the valve element 5d is pushed up from the valve seat 10d, the air passes through the valve clearance to flow into the passage 3j, wherefrom it flows through the passages 2c and 2b to the port 14.

The valve means E provides an afterburn check valve ABV which is controlled by manifold vacuum introduced into the diaphragm chamber 3k formed on one side of the diaphragm portion 4e opposite to the side facing the concaved portion 1e in a manner that when the manifold vacuum has increased beyond a predetermined value, the valve is opened so as to release the secondary air supplied from the air pump toward the air cleaner. This is to prevent afterburn which might occur when the throttle valve is fully closed to decelerate a vehicle running at a relatively high speed, due to a great increase of manifold vacuum which causes abrupt evaporation of fuel droplets attached to the wall of the intake passage thereby causing rich fuel-air mixture which is mostly exhausted into the exhaust system as uncombusted mixture and is combusted in the exhaust system where secondary air is supplied. Referring to FIGS. 1-7 in this connection, the air introduced into the passage 3f through the port 11 flows to the passage 2d, and if the valve element 5e is opened, the air is then conducted through the passages 3i, 2e, and 2c, and then it further flows through the passage 2b to the port 14 so as to be discharged therefrom.

From the foregoing, it will be appreciated that the present invention only requires individually to produce first and second dish-like members, an intermediate member and a diaphragm element which are all relatively simple and effectively two-dimensional in structure, and several valve elements and valve seat elements which are also very simple in structure, and to assemble them together in an overlaying manner to provide a composite valve which incorporates a plurality of valve means adapted to operate in relation to one another, and is characterized by a simple design and a requirement for simpler and less expensive manufacturing and assembling processes.

Although the invention has been shown and described with respect to a preferred embodiment thereof, it should be understood by those skilled in the art that various changes and omissions of the form and detail thereof may be made therein without departing from the scope of the invention in accordance with the function or system of individual composite valves required.