ISOLATION VALVE WITH INTEGRATED SENSOR
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the benefit of U.S. Provisional Application Serial No.
61/346,641, filed May 20, 2010, the entire contents of which is hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to an isolation valve assembly that includes a sensor
integrated with the valve to measure at least one valve operating characteristic.
BACKGROUND OF THE INVENTION
[0003] Valves are employed in a multitude of industries to control flow of liquids and/or
gases. One application for such control valves appears in vehicles with stored fuel to control a
vehicle's evaporative emissions resulting from fuel vapors escaping from the vehicle's fuel
system. Evaporative emissions of modern vehicles are strictly regulated in many countries. To
prevent fuel vapors from venting directly to the atmosphere, a majority of vehicles manufactured
since the 1970s include specifically designed evaporative emissions systems. Additionally, in
recent years vehicle manufacturers began developing fully sealed fuel delivery to their engines.
[0004] In a typical evaporative emissions system, vented vapors-from the fuel system are
sent to a purge canister containing activated charcoal. The activated charcoal used in such
canisters is a form of carbon that has been processed to make it extremely porous, creating a very
large surface area available for adsorption of fuel vapors and/or chemical reactions. During
certain engine operational modes, with the help of specifically designed control valves, the fuel
vapors are adsorbed within the canister. Subsequently, during other engine operational modes,
and with the help of additional control valves, fresh air is drawn through the canister, pulling the
fuel vapor into the engine where it is burned.
[0005] Emissions systems having higher operational pressures may need specialized
isolation valves to handle larger pressure ranges. However, there is a desire for an isolation valve
that can monitor and control vapor flow at high pressures while remaining compact and easy to
install.
SUMMARY OF THE INVENTION
[0006] An isolation valve according to one embodiment of the invention comprises an
electrically-actuated solenoid valve, at least one port having a port extension, and a sensor
assembly coupled to the port extension. The sensor assembly includes a printed circuit board, an
integrated circuit disposed on the circuit board, and at least one pressure sensor coupled to at
least one port extension to measure a vapor pressure in the port extension.
[0007] An isolation valve according to another embodiment of the invention comprises an
electrically-actuated solenoid valve, a pressure-actuated relief valve, a fuel tank port having a
first port extension, and a canister port that is offset from the fuel tank port in either a vertical
direction and/or a horizontal direction and having a canister port extension. The valve also has a
sensor assembly coupled to both the fuel tank port extension and the canister port extension. The
sensor assembly includes a printed circuit board, an integrated circuit disposed on the circuit
board, a temperature sensor, at least one pressure sensor coupled to the fuel tank extension
and/or the canister port extension to measure a vapor pressure, a plurality of terminals, and a
connector that forms a signal path from the terminals to a controller. In this embodiment, the
sensor assembly is coupled to both the fuel port extension and the canister port extension, and
the fuel tank port extension and the canister port extension extend substantially parallel to each
other between their respective ports and the sensor assembly. The solenoid valve and the
pressure-actuated relief valve selectively control vapor flow between the fuel tank port and the
canister port.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 is a cross-sectional view of a valve assembly having an integrated sensor
according to one embodiment of the invention;
[0009] Figure 2 is another cross-sectional view of the valve assembly of Figure 1;
[0010] Figure 3 is an exploded view of the valve assembly shown in Figure 1;
[0011] Figure 4a is a perspective view of one embodiment of a sensor assembly to be
integrated into the valve assembly of Figure 1;
[0012] Figures 4b is a top view of one embodiment of a sensor assembly to be integrated into
the valve assembly of Figure 1;
[0013] Figures 4c is a side sectional view of one embodiment of a sensor assembly to be
integrated into the valve assembly of Figure 1.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Figures 1 through 3 illustrate an isolation valve 1 according to one embodiment of the
invention. The isolation valve 1 includes a coil assembly 2 and a valve assembly 3. The valve
assembly 3 includes a valve housing 4 that houses internal components of the valve assembly 3
in a compact manner, while the coil assembly 2 includes a coil housing 5 that houses the internal
components of the coil assembly 2, including but not limited to a solenoid 12 and a sensor
assembly 13, which may both be controlled by a controller 6. In one embodiment, the sensor
assembly 13 is heat-staked into the valve housing 4 and covered by the coil assembly 2.
However, other methods of incorporating the sensor assembly 13 into the isolation valve 1 may
be used without departing from the scope of the invention.
[0015] The isolation valve 1 may be configured to control vapor flow. In one application, the
isolation valve 1 controls vapor flow between a fuel tank and a purge canister via a first port 14
and a second port 16, but the isolation valve 1 may be used in other applications as well. For
explanatory purposes only, the first port 14 may referred to herein as an inlet port or fuel tank
port and the second port 16 may be referred to herein as an outlet port or a canister port, but
those of ordinary skill in the art will understand that the ports 1 , 16 can have any function
without departing from the scope of the invention. Moreover, the valve assembly 3 may include
multiple ports and outlets and still be within the scope of the invention.
[0016] As shown in Figures 1 and 2, the fuel tank port 14 and canister port 16 may be offset
from each other both vertically and horizontally. Although Figure 2 shows the tank port 14 above
and to the right the canister port 16, other orientations may be used without departing from the
scope of the invention. This offset configuration allows a tank port extension 14a and a canister
port extension 16a to be disposed next to each other so that they can both reach the same sensor
assembly 13, allowing the single assembly 13 to monitor multiple pressures, such as fuel tank
pressure and canister pressure, by including multiple pressure sensors 18 on the same sensor
assembly 13. Note that the ports 14, 16 and their corresponding extensions 14a, 16a can have any
configuration and orientation as long as both of the ports 14, 16 reach the sensor assembly 13,
and the extensions 14a, 16a may even be bent at various angles to accomplish this.
[0017] The sensor assembly 13 itself may be disposed in a tray 20, which may be formed as
part of the valve housing 4. The tray 20 may be configured to accommodate a connector 2 1 that
includes connector terminals 1a that provide an electrical link between terminals 22 on the
sensor assembly 13 (as shown in Figure 4a) and any component outside the valve assembly 3.
The terminals 21a can be routed in any known manner and may include additional terminals to
create the electrical link.
[0018] As shown in Figure 2, the tray 20 may accommodate one or more seals, such as Orings
23, disposed between the sensor assembly 13 and the port extensions 14a, 16a to ensure a
tight seal that directs vapor from the port extensions 14a, 16a to the sensors 18. Those of
ordinary skill in the art will understand that other seals may be used without departing from the
scope of the invention.
[0019] The isolation valve 1 shown in Figures 1 through 3 is only one possible example of
how the inventive structure can be incorporated. One possible isolation valve 1 that can
incorporate the inventive structure is described in co-pending, commonly-assigned U.S. Patent
Application No. 12/749,924, filed on March 30, 2010, the disclosure of which is incorporated
herein by reference in its entirety. However, the offset configuration and the spatial relationship
between the ports 14, 16, the port extensions 14a, 16a, and the sensor assembly 13 can be
incorporated into any valve assembly where monitoring of multiple ports is desired.
[0020] In one embodiment, the fuel tank port 14 is connected to a fuel tank (not shown) and
the canister port 14 is connected to a purge canister (not shown). The valve housing 4
accommodates a relief valve 28 whose components may be combined into a single unit via any
appropriate manufacturing process, such as overmolding. The relief valve 28 opens and closes a
vent passage 30 in the canister port 16. In one embodiment, the relief valve 28 opens to create a
vapor path from the fuel tank to the canister when the fuel tank pressure is above a
predetermined pressure value representing an over-pressure condition of the fuel tank.
[0021] The coil assembly 2 may include the solenoid 12 arranged inside the coil housing 5.
Energization of the solenoid 12 may be triggered by a control signal from the controller 6. In one
embodiment, the solenoid-actuated valve 32 may open and close in response to energization and
de-energization of the solenoid 12. In one embodiment, the solenoid-actuated valve 32 may
include an armature 33 controlled by energization and de-energization of the solenoid 12. The
armature 33 may control flow through a passage 34, and the combined operation of the
electrically-controlled armature 33 in the coil assembly and the pressure-controlled operation of
the relief valve 28 directs vapor flow in the vapor path so that the vapor can flow in a number of
ways, including directly from the fuel tank port 14 to the canister port 16, over or under the
passage 34, through the passage 34, and/or through the relief valve 28.
[0022] More particularly, in one embodiment, when the solenoid actuated valve 32 is
energized and the tank pressure reaches a predetermined level, the armature 33 withdraws and
opens the passage 34 to open a vapor path and allow vapor to flow from the fuel tank to the
canister. The specific vapor path taken by vapor flowing through the solenoid actuated valve 32
and/or the relief valve 28 will depend on the combination of the tank pressure and the
energization state of the solenoid 12, which controls the open/closed position of the solenoid
actuated valve 32.
[0023] In the embodiment shown in Figures 1 through 3, the coil housing 5 may be attached
to the valve housing 4 via tabs 37 formed on the coil housing 5.
[0024] Figures 4a, 4b, and 4c show one embodiment of the sensor assembly 13 to be
integrated into the valve assembly 3. The assembly 13 may include a printed circuit board (PCB)
40 supporting one or more of the pressure sensors 18. The PCB 40 has one or more holes 42
aligned with the pressure sensors 18, which are in turn aligned with the fuel tank port extension
14a and the canister port extension 16a to provide a vapor path between the fuel tank port 14, the
canister port 16, and their corresponding pressure sensors 18. The sensor assembly 13 may also
include an application-specific integrated circuit (ASIC) 44 to receive signals from the pressure
sensors 18, process them, and generate an output signal that is output to a processor (not shown).
[0025] In one embodiment, the ASIC 44 may be placed on the underside of the PCB 40 to
make more room for the pressure sensors 18. Those of ordinary skill in the art will understand
that the components attached to the PCB 40, including the pressure sensors 18 and ASIC 44, can
be configured in any manner to form the sensor assembly 13 without departing from the scope of
the invention. Also, the pressure sensors 8 may be disposed underneath covers 46
[0026] In one embodiment, the sensors 18 may measure fuel tank pressure in two ranges
instead of one to accommodate the large operating pressure range found in isolated fuel systems.
Small pressure variations may be measured with high resolution, while larger pressure variations
may be measured with lower resolution. The specific pressure ranges and resolution levels
selected for the sensors 18 may be based on, for example, the particular application in which the
isolation valve 1 is used or customer specifications. In one example, one sensor 18 on the
assembly 13 may measure a pressure range from -12 kPa to 30 kPa while another sensor 18 on
the same assembly 13 may measure a pressure range from -4 kPa to +4 kPa.
[0027] The ASIC 44 may also include a temperature sensor that generates a signal reflecting
the fuel vapor temperature. In one embodiment, the temperature sensor in the ASIC 44 indicates
the temperature in the tray 20, which corresponds to a temperature. Based on the pressure and
temperature readings obtained by the ASIC 44, the controller 6 can determine whether a given
pressure change is due to a leak or due to a fuel temperature change affecting the fuel
vaporization rate. In one embodiment, the small range/high resolution pressure sensing, large
range/low resolution pressure sensing, and temperature sensing are all conducted via the single
assembly 13 shown above.
[0028] For example, if the pressure sensors 18 indicate a pressure drop and the temperature
sensor in the ASIC 44 indicates a temperature drop, this may indicate that the pressure drop is
due to decreased fuel vaporization instead of a system leak. In one embodiment, one pressure
sensor 8 measures pressure over a small range and at high resolution to monitor canister
pressure and the other pressure sensors measures pressure over a large range at a lower
resolution to monitor tank pressure. However, additional sensors 18 and/or different types of
sensors may be used to measure other ranges and resolutions if desired. Also, a single sensor 18
may have multiple ranges, resolutions, and functions, eliminating the need for multiple sensors
18.
[0029] While the best modes for carrying out the invention have been described in detail,
those familiar with the art to which this invention relates will recognize various alternative
designs and embodiments for practicing the invention within the scope of the appended claims.
CLAIMS
1. An isolation valve (1), comprising:
a solenoid-actuated valve (32);
at least one port (14, 16) having a port extension (14a, 16a);
a sensor assembly (13) coupled to the port extension (14a, 16a), wherein the
sensor assembly (13) includes
a printed circuit board (40),
an integrated circuit (44) disposed on the circuit board (40), and
at least one pressure sensor (18) coupled to said at least one port extension
(14a, 16a) to measure a vapor pressure in said at least one port extension (14a 16a).
2. The isolation valve (1) of claim 1, wherein said at least one port (14, 16)
comprises:
a first port (14) having a first port extension (14a), and
a second port (16) that is offset from the first port (14), the second port (16)
having a second port extension (16a);
wherein the sensor assembly (13) is coupled to both the first and second port
extensions (14a, 16a).
3. The isolation valve (1) of claim 2, wherein said at least one pressure sensor (18) is
a single pressure sensor (18) that measures vapor pressure in both the first and second port
extensions (14a, 16a).
4. The isolation valve (1) of claim 2, wherein said at least one pressure sensor (18)
comprises a first pressure sensor (18) that measures vapor pressure in the first port extension
(14a) and a second pressure sensor (18) that measures vapor pressure in the second port
extension (16a).
5. The isolation valve (1) of claim 2, wherein the first port (14) is a fuel tank port
(14) and the second port (16) is a canister port (16).
6. The isolation valve (1) of claim 2, wherein the first and second ports (14, 16) are
offset in at least one of a vertical direction and a horizontal direction with respect to each other.
7. The isolation valve (1) of claim 6, wherein the first port extension (14a) and the
second port extension (16a) extend substantially parallel to each other between their respective
ports (14, 16) and the sensor assembly (13).
8. The isolation valve (1) of claim 1, wherein said at least one sensor ( 18) measures
pressure at a large pressure range and a low resolution and also at a small pressure range and a
high resolution.
9. The isolation valve (1) of claim 1, wherein said at least one pressure sensor (18)
comprises:
a first sensor (18) that measures pressure at a large pressure range and a low
resolution, and
a second sensor (18) that measures pressure at a small pressure range and a high
resolution.
10. The isolation valve (1) of claim 1, wherein said at least one pressure sensor (18) is
disposed on a first side of the printed circuit board (40) and the integrated circuit (44) is disposed
on a second side of the printed circuit board (40).
11. The isolation valve (1) of claim 1, wherein the sensor assembly (13) further
comprises a temperature sensor (18).
12. The isolation valve (1) of claim 1, wherein the sensor assembly (13) includes a
plurality of terminals (21a), and wherein the isolation valve (1) further comprises a connector
(21) that forms a signal path from the terminals (21a) to a controller (6).
13. The isolation valve (1) of claim 1, further comprising a pressure-actuated relief
valve (28).
14. An isolation valve (1), comprising:
a solenoid-actuated valve (32);
a pressure-actuated relief valve (28)
a fuel tank port (14) having a fuel tank port extension (14a),
a canister port (16) that is offset from the fuel tank port (14) in at least one of a
vertical direction and a horizontal direction, the canister port (16) having a canister port
extension (16a),
a sensor assembly (13) coupled to the both the fuel tank port extension (14a) and
the canister port extension (16a), wherein the sensor assembly (13) includes
a printed circuit board (40),
an integrated circuit (44) disposed on the circuit board (40),
a temperature sensor (18),
at least one pressure sensor (18) coupled to at least one of said fuel tank
extension (14a) and said canister port extension (16a) to measure a vapor pressure,
a plurality of terminals (21a); and
a connector (21) that forms a signal path from the plurality of terminals
(21a) to a controller (6),
wherein the sensor assembly (13) is coupled to both the fuel port extension (14a)
and the canister port extension (16a), and
wherein the solenoid-actuated valve (32) and the pressure-actuated relief valve
(28) selectively control vapor flow between the fuel tank port (14) and the canister port (16).
15. The isolation valve (1) of claim 14, wherein said at least one pressure sensor (18)
is a single pressure sensor (18) that measures vapor pressure in both the fuel tank port extension
(14a) and the canister port extensions (16a).
16. The isolation valve (1) of claim 14, wherein said at least one pressure sensor (18)
a that measures pressure at a large pressure range and a low resolution and also at a small
pressure range and a high resolution.
17. The isolation valve (1) of claim 14, wherein said at least one pressure sensor (18)
comprises a first pressure sensor (18) that measures vapor pressure in the fuel tank port extension
(14a) and a second pressure sensor (18) that measures vapor pressure in the canister port
extension (16a).
18. The isolation valve (1) of claim 17, wherein said at least one pressure sensor (18)
comprises:
a first pressure sensor (18) that measures pressure at a large pressure range and a
low resolution, and
a second pressure sensor (18) that measures pressure at a small pressure range and
a high resolution.
19. The isolation valve of claim 14, wherein said at least one pressure sensor (18) is
disposed on a first side of the printed circuit board (40) and the integrated circuit (44) is disposed on a second side of the printed circuit board (40).