JPS62253952A - Exhaust-gas recirculating valve assembly - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a valve assembly for controlling exhaust gas recirculation in an internal combustion engine.

When employing an electrically actuated valve assembly to control exhaust gas recirculation, one actuator should be isolated from the exhaust gas to ensure proper operation. Electrically actuated valve assemblies previously proposed for controlling exhaust gas recirculation have not isolated the actuator from stray gases in a practical manner.

The present invention provides a practical electrically actuated exhaust gas recirculation valve assembly that isolates the actuator from the exhaust gas to ensure proper operation.

In one preferred embodiment of an exhaust gas recirculation valve assembly employing the present invention, the valve member controls the flow of exhaust gas from the exhaust gas chamber through a graduated valve seat. A solenoid coil is positioned outside the chamber, and the valve member has a valve stem extending to a solenoid armature surrounded by the coil. The valve stem is surrounded about the solenoid coil and a pair of spring-loaded seals sealing the opening into the chamber, and the armature-valve member-seal subassembly floats laterally to connect the solenoid coil and the valve stem. Compensate for potential misalignment with the exit.

The details and other features and advantages of three embodiments of the invention are set forth in the remainder of the specification and illustrated in the accompanying drawings.

Referring first to FIGS. 1-3, an exhaust gas recirculation valve assembly 1o is an inlet 14 for receiving exhaust gas from the engine.
The base 12 includes a base 12 having a diameter. A cover 1 is placed above the base 12.
6 containing an exhaust gas chamber 18, each base 12 having a valve seat 2
3 graduated outlets 20a, 20 surrounded by 2
b, has 20c.

A solenoid coil 24 is mounted on the bracket 26 so as to cover each valve seat 22. Each coil 24 has an armature 28
A valve stem 30 extends from each armature 28 to a valve member 32 disposed within the chamber 18 .

A pair of seals 34 and 36 surround each valve stem 30. Each upper or bracket seal 34 is attached to the valve stem 3
a central disc portion 38 that embraces the bracket 26, and a peripheral lip 40 biased by a spring 42 to engage the bracket 26. The bracket seal 34 is attached to the valve stem 30 and the armature 2.
The opening 44 through the bracket 26 is sealed around 8.

Each lower cover seal 36 has a hub 4 that hugs a valve stem 30.
6 and a peripheral flange portion 48 biased by a spring 42 into engagement with the cover 16. Cover seal 36 seals an opening 50 through cover 16 around valve stem 30.

Seals 34 and 36 are formed of sintered graphite bronze 5 stainless steel or other material selected to provide the desired smoothness and wear resistance. The hole 52 through the hub 46 of the lower seal 36 is chamfered at the top and bottom to allow the valve stem 30 to easily slide through the seal 36. No chamfering is required on the hole 54 through the thin central disc portion 38 of the upper seal 34.

To construct the valve assembly 10, the three solenoid coils 24 are secured to the bracket 26 and the coil-bracket subassembly is turned upside down.

Place the lower seal 36, spring 42 and upper seal 34 on the valve stem 30, place the armature 28 on the valve stem 30, and turn the tip 56 of the valve stem 3o over to remove the armature - valve member -.
Three armature-valve member-seal subassemblies 55 are created by securing the seal subassemblies. A spring 57 is inserted into each solenoid coil 24 and then armature 28 is inserted into the solenoid coil 24 through the bracket opening 44. Cover 16 is secured to base 12 with fasteners 58, the cover base subassembly is inverted and assembled with valve member 32 passing through opening 50 and engaging valve seat 22, and fasteners 60 are secured to bracket 26.

Spring 42 reacts between central disk portion 38 of upper seal 34 and peripheral flange portion 48 of lower seal 36 to engage seal 34 with bracket 26 and seal 36 with cover 16, respectively.

In operation, each spring 57 urges a respective armature 28 and valve stem 30 to engage a respective valve member 32 with an associated valve seat 22. When the solenoid coil 24 is energized, the respective armature 28 and valve stem 30 are lifted against the bias of the respective spring 57, and the respective valve member 32 is lifted away from the associated valve seat 22. to allow exhaust gas recirculation.

Preferably, the areas of the eight ports 20a, 20b, 20c are calibrated as a binary series such that the area of the outlet 20b is the area of the outlet 2.
0a and the area of the outlet 20c is twice that of the outlet 20b, but in some applications,
Other combinations of exit areas may be used. Exhaust gas recirculation is calibrated by energizing the appropriate solenoid coil(s) 24 to lift the appropriate valve member(s) away from the associated valve seat(s) 22. Measured by allowing recirculation of exhaust gas through one or more of the outlets 20a, 20b, 20c.

Each solenoid coil 24 has a pole piece 62 threaded into a yoke 64. The adjustment of the pole piece 62 within the yoke 64 is due to the preload that the associated spring 57 applies to the corresponding armature-stem-valve member and the corresponding armature 20 when the corresponding coil 24 is unenergized, respectively. and the corresponding armature-valve stem-valve member stroke when the corresponding coil 24 is energized.

Although assembly 10 is shown here as having a circular base 12, it will be appreciated that other configurations may be employed within the space limitations of the particular engine application. ' Referring now to FIG. 4, the exhaust gas recirculation valve assembly 110
includes a base 112 having an inlet 114 for receiving exhaust gases from the engine.

A cover 116 is provided above the base 112 to cover the wandering gas chamber 1.
18, the base 112 has three graduated outlets 120 (only one shown) each surrounded by a valve seat 122.

A solenoid coil 124 is mounted on the bracket 126 so as to cover each valve seat 122. Each coil 124 surrounds an armature 128 and a valve stem 130 extends from each armature 128 to a valve member 132 disposed within chamber 118 .

A pair of seals 134 and 136 surround each valve stem 130. Each upper bracket seal 134 is attached to the valve stem 1
30 and engage the bracket 126 with the spring 14
2. Bracket seal 134 seals bracket 1 around valve stem 130 and armature 128.
The opening 144 through 26 is sealed.

Each lower cover seal 136 has a hub 146 that embraces the valve stem 130 and a peripheral flange portion 148 biased by a spring 142 into engagement with the cover 116. Cover seal 136 seals opening 150 through cover 116 around valve stem 130 .

Seals 134 and 136 are sintered graphite bronze.

Constructed of stainless steel or other material selected to provide the desired smoothness and abrasion resistance.

The base 112 of the assembly 110 directs the measured exhaust gas to outlet 1.
20 to a common discharge opening 139.

The embodiment shown in FIG. 4 is assembled, adjusted and operated in the same manner as described above for the embodiment shown in FIGS. 1-3.

Referring now to FIGS. 5-6, an exhaust gas recirculation valve assembly 210 includes an inlet 21 for receiving exhaust gas from the engine.
4. Includes a base 212 having a diameter of 4. Above the base 212 is a cover 216 that encloses the exhaust gas chamber 218 and covers the base 212.
has three calibrated outlets 220 (only one shown) each surrounded by a valve seat 222.

A solenoid coil 224 is mounted on the bracket 226 so as to cover each valve seat 222 . Each coil 224 surrounds an armature 228 with a valve stem 230 extending from each armature 228 to a valve member 232 disposed within chamber 218 .

A pair of seals 234 and 236 surround each valve stem 2 and 30. Each upper bracket seal 234 has a central disk portion 238 that embraces the valve stem 230 and the bracket 22.
6 and a circumferential lip 240 biased by a spring 242 into engagement with the peripheral lip 240 . The bracket seal 234 is attached to the valve stem 2
30 and the opening 244 through the bracket 226 around the armature 228 is sealed.

Each lower cover seal 236 has a spring 2 for engaging the cover 216 with a central disc portion 246 that embraces the valve stem 230.
42 and a peripheral rim 248 biased by 42. A cover seal 236 seals the cover 21 around the valve stem 230.
6 is sealed.

Seals 234 and 236 are formed of a material such as sintered graphite bronze selected to provide the desired smoothness and wear resistance. Addition.

The central disk portion 246 of the lower seal 236 is connected to the mandrel 23.
valve stem 23 to prevent deposits from accumulating on the valve stem 23.
Rub 0.

To construct valve assembly 210, three solenoid coils 224 are secured on bracket 226 and valve member 232 is secured.
, lower seal 236, spring seat 255a and return spring 2
55b, place the seal spring 242 and upper seal 234 on the valve stem 230, place the armature 228 on the valve stem 230, and flip the tip 256 of the valve stem 230 to secure the armature-valve member-seal subassembly. This creates three armature-valve member-seal subassemblies 255. The armature 228 is then inserted into the solenoid coil 224 through the bracket opening 244, the cover 216 and base 212 are assembled with the valve member 232 passing through the opening 250 and engaging the valve seat 222, and the fastener 260 is inserted into the bracket 226. and insert and screw into the base 212 through the cover 216.

Spring 242 reacts between central disc portion 238 of upper seal 234 and central disc portion 248 of lower seal 236 to pull seal 234 between bracket 226 and seal 236.
are respectively engaged with the cover 216.

In operation, each spring 255b is connected to a respective armature 2
28 and valve stem 230 to urge the corresponding valve member 2
32 into engagement with the associated valve seat 222 . When the solenoid coil 224 is energized, each armature 228 and valve stem 230 are lifted against the bias of the corresponding spring 255b and the corresponding valve member 232 is lifted away from the associated valve seat 222. 9 allows exhaust gas recirculation.

Each solenoid coil 224 has a pole piece 262 threaded into a yoke 264. Adjustment of the pole piece 262 within the yoke 264 determines the air gap and stroke of its corresponding armature-stem-valve member. After adjusting the pole pieces 262 within the yoke 264, the yoke 264 is laterally crimped to prevent changes in its adjustment.

Each valve member 232 swivels onto a ball 266 formed at the end of the corresponding valve stem 230 to attach the corresponding valve seat 222.
ensuring proper alignment of valve member 232 above.

Note that each orifice 220 has a narrowest opening at the top and a wider area 268 at the bottom. With this configuration, sediment that tends to accumulate within the orifice 220 is forced into the wider area 268 by the valve member 232 in the direction of flow through the orifice 220, reducing the likelihood of clogging the orifice 220.

As can be seen from the above, varying the extent to which each valve member is lifted away from its corresponding valve seat;
Exhaust gas recirculation can therefore also be measured with these assemblies by actuating one or more solenoids, such as linear solenoids, that vary the flow area between the valve member and the corresponding valve seat. Furthermore, the time during which each valve member is lifted away from its corresponding valve seat is varied.

Thus, one or more solenoids may be operated as a pulse width modulated or frequency modulated solenoid to vary the flow past the valve member.

Moreover, in each embodiment, the solenoid 24.124
, 224 need not be precisely aligned on the valve seat 22, 122° 222. However, in one aspect of the invention, the valve stem 30, 130, 230 is not compressed by a fixed seal within the cover opening 50° 150.250. Instead, an armature-valve member-seal subassembly 55,1
55, 255 float laterally to open the bracket opening 44,
144, 244 and cover openings 50, 150, 250
This compensates for potential misalignment of the solenoid coils 24, 124, 224 while still ensuring that the solenoid coils 24, 124, 224 are sealed.

Note that the lower side or the central disk portion 2 of the cover seal 236
46 is slightly convex to aid in centering within opening 250 during assembly, but still allow seal 236 to float laterally as described above.

[Brief explanation of drawings]

FIG. 1 shows the first part of an exhaust gas recirculation valve assembly incorporating the present invention.
FIG. 2 is a bottom view of the embodiment shown in FIG. 1, showing the outlet of the scale chamber, and FIG. 3 shows the armature-valve employed in the embodiment shown in FIG. 1. FIG. 3 is an enlarged view of the member-seal subassembly. FIG. 4 shows a second exhaust gas recirculation valve assembly incorporating the present invention.
FIG. 5 is a partial cross-sectional view of a third embodiment of an exhaust gas recirculation valve assembly incorporating the present invention; FIG. 6 is a plan view of the fifth embodiment. . [Explanation of symbols of main parts]

Claims (1)

[Claims] 1. An exhaust gas chamber (18; 118; 218), an inlet opening (14; 114; 214) to the chamber, and an outlet opening (20a, 20b, 20c; 120;
220) and a valve seat (220) surrounding said inlet or said outlet.
22; 122; 222);
; 212), said base (12; 112; 212) having a cover (1) closing said chamber (18; 118; 218).
6; 116; 216), the cover (16; 116)
; 216) has an opening (5) generally aligned with the valve seat (22; 122; 222).
0;150;250) and the opening (50;150;25
a valve stem (30; 130; 230) passing through the valve stem (30; 130; 230); and a valve member (30; 130; 230) attached to one end of the valve stem (30; 130;
32; 132; 232) and the valve stem (30; 130; 230) at the other end of the valve stem (30; 130; 230) to actuate the valve stem (30; 130; 230).
;132;232) to the valve seat (22;122;222)
) an actuator (24; 124; 224) actuatable for reciprocation into and out of engagement with the exhaust gas recirculation valve assembly (10; 110; 210);
The valve assembly (10; 110; 120) further includes the chamber (
18; 118; 218) and the valve stem (30; 1
a movable seal (36; 136;
236) surrounding the valve stem (30; 130; 230) and urging the movable seal (36; 136; 236) into engagement with the cover (16; 116; 216) to open the cover opening. and a spring (42; 142; 242) sealing the valve (50; 150; 250). 2. In claim 1, the valve member (32; 132; 232) is connected to the chamber (18; 118).
; 218) at one end of the valve stem (30; 130; 230);
30) has a solenoid armature (28; 128; 2) at the other end.
28) is attached, and the armature (28; 128; 2
28) is surrounded by a solenoid coil (24; 124; 224) which reciprocates said valve member (32; 132; 232) into and out of engagement with said valve seat (22; 122; 222). The valve stem (30; 130
; 230); an exhaust gas recirculation valve assembly; 3. In claim 2, a bracket (24; 124; 224) supporting the solenoid coil (24; 124; 224) on the base (12; 112; 212) is provided.
26; 126; 226), and the bracket (26;
126; 226) is the cover opening (50; 150; 2
apertures (44; 144; 244) generally aligned with
), the valve stem (30; 130; 230) passes through the bracket opening (44; 144; 244), and the bracket (26; 126; 226) and the cover (1
6; 116; 216) and the valve stem (30; 13).
a movable bracket seal (34; 0; 230);
134; 234), and this movable bracket seal (
34; 134; 234) is the spring (42; 142; 2
42) by said bracket (26; 126; 226)
said bracket opening (44;
144; 244).