Low-viscosity vane pump for evaporative emission system

Abstract

A low viscosity vane pump for an evaporative emission system includes a housing providing a bore in fluid communication with an inlet passage and an outlet passage, and a rotating assembly disposed within the bore and configured to rotate relative to the bore. The rotating assembly includes a rotor mounted on the shaft and having a plurality of slots. The rotor has a first face portion and a second face portion engaged with the housing. A vane is received in each slot, each vane having a first surface and a second surface extending a length from a first end to a second end in a longitudinal direction. The first ends are received in their respective slots. The rotating assembly includes a recess on at least one of the first face portion, the second face portion, the first surface of the first end portion, and the second surface of the first end portion.

Description

Technical Field

[0001] The invention relates to a vane pump and an evaporative emission system including the vane pump. Background Art

[0002] Evaporative emissions systems have long been a necessity for gasoline-powered vehicles. The system must be leak tested during the vehicle startup procedure to ensure that fuel vapors are not escaping into the atmosphere. A pump is used to create a vacuum or pressurize the system. An external filter is used to prevent contamination that could damage the pump or other parts of the system during operation. Several valves may be closed during this testing procedure to maintain system pressure, and the pressure is monitored to determine if any leaks are present.

[0003] When a leak is present in the evaporative system at high ambient temperatures (>35°C), the gasoline vapor (VOC) escaping through the leak exceeds what the properly functioning evaporative system is designed to do. Over a 24 hour period, the amount of gas released from the vapor chamber of the fuel tank through a 1 mm leak can exceed the regulatory allowance for evaporative leaks by 10 times. Therefore, there is a need for an evaporative emissions system leak test that can quickly and accurately detect leaks in the system.

[0004] Vane pumps are designed so that during operation the vanes extend outward from the centerline of their supporting rotor, which compress the air and cause it to flow through the pumping chamber. The vanes are typically oriented perpendicular to the drive shaft and slide within corresponding slots in the rotor as the vanes follow the contour of the chamber wall during rotor rotation. The prior art uses vanes of rectangular design with smooth, uniform surfaces on all running surfaces of the rotor and vanes. Summary of the invention

[0005] In one example embodiment, a vane pump includes a housing providing a hole in fluid communication with an inlet channel and an outlet channel and a rotating assembly disposed in the hole and configured to rotate relative to the hole. The rotating assembly includes a rotor mounted on a shaft and having a plurality of slots. The rotor has a first face and a second face engaged with the housing. A blade is received in each slot, each blade having a first surface and a second surface extending in a longitudinal direction from a first end to a length of a second end. The first end is received in its corresponding slot. The rotating assembly includes a recess located on at least one of the first face, the second face, the first surface of the first portion, and the second surface of the first portion.

[0006] In another embodiment of any of the above, each vane comprises a substantially rectangular cross-section provided by spaced apart long sides in conjunction with spaced apart short sides. The long sides are provided by a first surface and a second surface, and the recess is provided on at least one of the first surface and the second surface.

[0007] In another embodiment of any of the above, the short sides extend a first width in a thickness direction transverse to the longitudinal direction, the long sides extend in a height direction transverse to the longitudinal direction and the thickness direction, and the recess has a second width in the thickness direction that is smaller than the first width.

[0008] In another embodiment of any of the above, the slot has a slot width, a slot height, and a slot depth. The first width is substantially equal to the slot width, and the first portion causes the first width to be at least partially disposed within the slot depth during operation of the vane pump.

[0009] In another embodiment of any of the above, a plurality of recesses are provided on each blade.

[0010] In another embodiment of any of the above, at least one recess is provided on each of the first face portion and the second face portion.

[0011] In another embodiment of any of the above, the recess extends to a distal end of the second portion.

[0012] In another embodiment of any of the above, the recess is provided on at least one of the first face portion and the second face portion.

[0013] In another embodiment of any of the above, the first face portion and the second face portion are each bounded by a perimeter, and the recess is completely contained within the perimeter.

[0014] In another embodiment of any of the above, the rotor and blades are plastic and the recess is defined by a molded surface.

[0015] In another embodiment of any of the above, the vane pump includes a motor connected to the rotating assembly via a shaft.

[0016] In another example embodiment, an evaporative emissions system including the vane pump includes a fuel system having a fuel tank and a carbon canister, the fuel system containing vapor. At least one valve is set in a closed position during a leak detection procedure. The vane pump includes a motor connected to a rotating assembly via a shaft. A controller is in communication with the pump, and the controller is configured to maintain pressure on the system having the vane pump during the leak test procedure. The rotating assembly is configured to collect vapor in the recess during operation.

[0017] In another embodiment of any of the above, each vane comprises a substantially rectangular cross-section provided by spaced apart long sides engaging spaced apart short sides. The long sides are provided by a first surface and a second surface, and the recess is provided on at least one of the first surface and the second surface.

[0018] In another embodiment of any of the above, the short side extends a first width in a thickness direction transverse to the longitudinal direction, and the long side extends in a height direction transverse to the longitudinal direction and the thickness direction. The recess has a second width in the thickness direction that is less than the first width. The groove has a groove width, a groove height, and a groove depth. The first width is substantially equal to the groove width, and the first portion causes the first width to be at least partially disposed within the groove depth during operation of the vane pump.

[0019] In another embodiment of any of the above, the recess is provided on at least one of the first face portion and the second face portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention may be further understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0021] Figure 1A Portions of an example evaporative fuel system are schematically shown.

[0022] Figure 1B is used for Figure 1A Schematic diagram of the leak detection module (LDM) of the system shown.

[0023] Figure 2A is a perspective view of an example rotary vane pump.

[0024] Figure 2B It is taken along line 2B-2B Figure 2A A cross-sectional view of the pump.

[0025] Figure 3A A front view of the pump is shown with the first plate removed, exposing the rotor in the middle plate.

[0026] Figure 3B It is a perspective view of the middle plate with the filter installed.

[0027] Figure 4A and 4B They are Figure 3B A first side perspective view and a second side perspective view of an intermediate plate are shown.

[0028] Figure 5 is a top view of the rotor.

[0029] Figure 6 is a broken side view of the blade.

[0030] Fig. 7A is a side view of another example blade.

[0031] Figure 7B yes Fig. 7A An end view of the blade is shown.

[0032] The embodiments, examples and alternatives in the preceding paragraphs, claims or the following description and drawings, including their different aspects or corresponding independent features, may be considered individually or in any combination. Features described in conjunction with one embodiment apply to all embodiments, unless these features are not matched. Corresponding reference numerals and names in different drawings represent the same elements. DETAILED DESCRIPTION

[0033] Figure 1A A portion of an example evaporative fuel system 10 is schematically shown. The system 10 includes a fuel tank 12 having a fuel filler 14 with a filler cap 16. A fuel pump 18 supplies gasoline, for example, from the fuel tank 12 to an internal combustion engine 20. A fuel level sensor 15 communicates with a controller 40 and measures the level of fuel within the fuel tank 12, which also correlates to the amount of fuel vapor within the fuel tank 12.

[0034] The system 10 is configured to capture and regulate the flow of fuel vapors within the system. In one example, a fuel tank isolation valve 24 is fluidly disposed between the fuel tank 12 and a carbon canister 22 that captures and stores fuel vapors for subsequent use by the engine 20. A purge valve 26 is fluidly connected between the carbon canister 22 and the engine 20. A controller 40 adjusts the position of the purge valve 26 to selectively provide fuel vapors to the engine 20 to utilize these fuel vapors during operation.

[0035] The integrity of the system 10 must be tested periodically to ensure that no fuel vapor is leaking from the system 10. One type of system 10 uses a leak detection module (LDM) 28, which can be used to evacuate and / or pressurize the system to determine if a leak exists, for example, using a pressure sensor 53. In an example leak test procedure, the purge valve 26 is closed and the controller 40 operates the leak detection module 28 to evacuate or pressurize the system. Another pressure sensor 51 may be used to monitor the pressure of the fuel vapor within the fuel tank 12 during other conditions. An optional ambient temperature sensor 55 is in communication with the controller 40. The temperature sensor 55 may help quantify the heat transfer characteristics of the fuel vapor within the fuel tank 12 relative to the surrounding atmospheric temperature.

[0036] LDM28 Figure 1BSchematically shown in . LDM28 includes a pump 30 disposed in a housing. An example pump is disclosed in U.S. Application No. 17 / 765,628, entitled “Pump for Evaporative Emission Systems,” filed on March 31, 2022, which is incorporated herein by reference in its entirety. Some consumers prefer to use vacuum-operated systems, while others prefer pressurized systems. Therefore, in order to provide a pressurized vapor emission system test, the pump 30 will draw air from the atmosphere through a filter 32 and direct the air toward the carbon canister 22. Another filter 34 may be provided on the other side of the pump 30 to protect the pump from debris. In order to provide a vapor emission system test of reduced pressure or negative pressure (i.e., vacuum), the pump 30 will draw air from the carbon canister 22 and exhaust it to the atmosphere. An example leak detection method is disclosed in U.S. Application No. 18 / 023,523, entitled “Entropy Method for Leak Detection Module for Evaporative Emission Systems,” filed on February 27, 2023, which is incorporated herein by reference in its entirety.

[0037] In one example, when LDM 28 is not performing leak detection of fuel system 10, canister valve solenoid (CVS) 31 is in an open position to allow air to pass through first fluid passage 61 between the remainder of system 10 and the atmosphere. This enables system 10 to draw air from the atmosphere as needed.

[0038] When the LDM 28 performs a leak test of the fuel system 10, the CVS 31 is in a closed position, which provides a second fluid passage 63 on the side of the carbon canister 22. The CVS check valve 33 is disposed in the second fluid passage 63 and selectively isolates the carbon canister 22 from the pump 30 and the atmosphere. The pressure sensor 53 is configured to read the pressure in the second fluid passage 63 when the CVS 31 is closed, but the pressure sensor may also be used for other purposes.

[0039] LDM 28 includes the necessary hardware to determine if system 10 is leaking to atmosphere. During leak testing, pump 30 is isolated from the amount of air being checked for leaks depending on how CVS check valve 33 is used. Pump 30 can create negative pressure (vacuum) or positive pressure in the evaporative emissions system depending on its direction of rotation as described above. The leak boundaries of system 10 include fuel filler 14 and cap 16, purge valve 26, the fresh air side of carbon canister 22 (the side connected to LDM 28), the vapor chamber of fuel tank 12, and the vapor lines connecting all components (including second fluid passage 63).

[0040] During the leak test, the pressure sensor 53 is in fluid communication with the second fluid passage 63 and monitors the pressure conditions generated in the system 10 by the pump 60. The pressure sensor 53 communicates with the controller 40, which determines whether there is a pressure change in the evaporative emission system within a predetermined time that may indicate a leak. Any pressure change detected by the pressure sensor 53 and monitored by the controller 40 indicates a leak. The OBDII diagnostic system 41 communicates with the controller 40 and uses the pressure information from the pressure sensor to generate an engine fault code, which can be stored and used to illuminate a "check engine" light on the vehicle dashboard indicating that vehicle maintenance is required. An example diagnostic system is disclosed in U.S. application No. 17 / 882,055, entitled "Evaporative Emission Leak Check Module with Integrated Control and Communication System," filed on August 5, 2022, which is incorporated herein by reference in its entirety.

[0041] The controller 40 and the OBDII system 41 may be integrated or separate. In terms of hardware architecture, such a controller may include a processor, a memory, and one or more input and / or output (I / O) device interfaces communicatively coupled via a local interface. The local interface may include, for example but not limited to, one or more buses and / or other wired (e.g., CAN, LIN, and / or LAN) or wireless connectors. The local interface may have additional elements omitted for simplicity, such as controllers, buffers (caches), drivers, repeaters, and receivers to enable communication. In addition, the local interface may include address, control, and / or data connectors to enable appropriate communication between the above components.

[0042] The controller may be a hardware device for executing software, particularly software stored in memory. The processor may be a custom or commercially available processor, a central processing unit (CPU), an auxiliary processor associated with the controller in a plurality of processors, a microprocessor-based semiconductor (in the form of a microchip or chipset), or generally any device for executing software instructions.

[0043] The memory may include any one or a combination of volatile storage elements (e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, VRAM, etc.) and / or non-volatile storage elements (e.g., ROM, etc.). In addition, the memory may include electronic, magnetic, optical and / or other types of storage media. The memory may also have a distributed architecture in which multiple components are remote from each other but accessible by a controller.

[0044] The software in the memory may include one or more separate programs, each of which includes an ordered list of executable instructions for implementing logical functions. System components implemented as software may also be understood as source programs, executable programs (object code), scripts, or any other entity including a set of instructions to be executed. When constructed as a source program, the program is translated by a compiler, assembler, interpreter, etc., which may or may not be contained in the memory.

[0045] When the controller is operating, the processor may be configured to execute software stored in the memory, to transfer data to and from the memory, and to generally control the operation of the computing device according to the software. The software in the memory is read in whole or in part by the processor, possibly buffered within the processor, and then executed.

[0046] exist Figure 2A An example leak detection module 28 is shown in greater detail in Module 28. Module 28 includes a pump 30 that receives atmospheric air through an inlet port 34. The pump provides pressurized air to an outlet port 36, which may be supplied to the carbon canister 22 or other evaporative component of the system 10 through a check valve 33.

[0047] The pump 30 has a housing 40 formed of a first plate 42 and a second plate 44 fixed on either side of an intermediate plate 46. It should be understood that the pump 30 can be constructed in a manner different from that disclosed. For example, an intermediate plate need not be used. In the example described, the inlet port 34 and the outlet port 36 are disposed on the edge of the intermediate plate 46, rather than on one or both of the first plate 42 and the second plate 44. Reference Figure 2A and 2B , the intermediate plate 46 has a first side 46a proximate to and abutting the first plate 42, and a second side 46b proximate to and abutting the second plate 44. In the example described, the first side 46a and the second side 46b abut and engage the first plate 42 and the second plate 44. The motor 48 is mounted on the first plate and rotationally drives the rotor 52 received in the hole 62 of the intermediate plate 46 via the shaft 50. The rotor 52 includes a hole 90 ( Figure 5 ).

[0048] In the example, the first plate 42, the second plate 44 and the intermediate plate 46 are made of a plastic material, such as nylon or polypropylene, which may be filled with graphite or Teflon. In one example, the plastic is injection molded, which provides a surface with characteristics that are identifiable and indicate the molding process (such as shrink lines and flow lines). The plates 42, 44, 46 include at least two locating holes 54, each of which is configured to temporarily receive a through pin during assembly of the pump 30 so that the plates are accurately aligned with each other. The fasteners 56 are received in the fastening holes 58 in the first plate 42, the second plate 44 and the intermediate plate 46. In the example, the ends of the fasteners 56 (which may be metal) are plastically deformed to securely hold the first plate 42 and the second plate 44 in a clamping relationship around the intermediate plate 46. Threaded fasteners, rivets or other types of fastening may also be used.

[0049] The example pump 30 is of rotary vane construction. Figure 3A and 3B , an oblong hole 62 is shown. However, a circular hole with an offset rotor may be used instead if desired. The rotor 52 includes a plurality of slots 64 around its circumference. The slots 64 slidably receive vanes 66 that are movable within the slots to seal the outer periphery of the hole 62 from centrifugal forces, as is known in rotary vane pumps. For the oblong hole 62, two cavities 80, 82 are provided to form a dual chamber configuration that balances the pressure on the rotor 52.

[0050] The passage 74a on the first side portion 46a fluidly connects the inlet 34 with the hole 62, such as Figure 3A and 4A The first passage 74a includes a first passage 76a fluidly connected to the ambient side V of the first cavity 80 and a second passage 78a fluidly connected to the ambient side V of the second cavity 82. The socket 68a is fluidly disposed in the first passage 74a between the inlet port 34 and the bore 62.

[0051] In a similar manner, the second channel 74b on the second side portion 46b fluidly connects the outlet 36 with the aperture 62, as shown in FIG. Figure 4B The second passage 74b includes a second passage 76b fluidly connected to the pressure side P of the second cavity 82 and a second passage 78b fluidly connected to the pressure side P of the first cavity 80. The socket 68b is fluidly disposed in the second passage 74b between the outlet port 36 and the bore 62.

[0052] At least one of the sockets 68a, 68b receives a filter 32 (e.g., foam), but both sockets 68a, 68b may include a filter 32 if desired. In this way, contaminants are filtered from the system 10 and no external lines or fittings are required due to the inclusion of an internal filter within the pump 30. The LDM 28 does not need to be protected against ISO ultrafine dust (1-22 microns) because it does not have a calibrated hole included in some types of leak detection pumps. The type of foam filter element that may be included in the LDM 28 may not prevent ultrafine dust from entering the pump assembly. On the contrary, this is not a risk to pump performance because the dust is relatively low in concentration relative to the volume of air passing through the pump 30.

[0053] Pumps designed to move fluids rely on lubrication of the material being pumped. Since air pumps do not have liquid to lubricate the rotating components during vane extension, the pump relies on centrifugal force to extend the vanes. Condensation in a vane pump of (water) vapor, such as in the fuel system 10, can cause sticking of the rotating and sliding components due to adhesion created between two wetted surfaces. The disclosed vane pump reduces sticking in the presence of vapor by providing one or more channels or recesses along the exit path of the vanes that allow condensation to accumulate and / or due to centrifugal forces created during rotation.

[0054] The pump 30 includes a housing provided by one or more plates 42, 44, 46 as described above. The aperture 62 is in fluid communication with an inlet passage and an outlet passage (e.g., channels 74a, 74b). These passages may be configured in any suitable manner to supply air to and from the aperture 62 for the fuel system 10.

[0055] A rotating assembly including rotor 52 and vanes 66 is disposed within bore 62 and configured to rotate relative thereto. Volumes are circumferentially disposed between adjacent vanes 66, forming chambers that change size during rotation to create a pressure differential across pump 30. As the rotating assembly is driven by motor 48, centrifugal force causes each vane 66 to slide radially outward relative to its corresponding slot 64 to sealingly engage the outer circumferential wall of bore 62. Because each vane 66 must slide rapidly in and out relative to its slot during rotation, any stiction that prevents this sliding motion will prevent the vanes 66 from sealing, thereby causing pump 30 to fail to achieve its desired pressure.

[0056] To reduce the effects of viscosity (especially in the presence of steam), one or more recesses are provided in the rotating assembly at the rotating and / or sliding interface. However, the recesses are configured so that pressurized air cannot leak from the high pressure chamber to the low pressure chamber over the rotor 52 or blades 66.

[0057] The rotor 52 has a first face portion 98 and a second face portion 100 ( Figure 5 and 7A), which engage and rotate relative to the housing during operation. In order to reduce sticking between the rotor 52 and the housing, at least one recess 102 is provided on at least one of the first face portion 98 and the second face portion 100. In the example described, a plurality of L-shaped recesses are provided. The first face portion 98 and the second face portion 100 are each bounded by the outer periphery 96 (dashed line), and the recess 102 is completely contained within the outer periphery 96. This better prevents leakage from one chamber to another.

[0058] Example blades 66, 166 in Figure 6-7B 6 and are generally referred to as "vanes 66". Each vane 66 has a substantially rectangular cross-section provided by spaced apart long sides 108, 110 joined to spaced apart short sides 112, 114. The long sides 108, 110 are provided by the first surface 104 and the second surface 106. The short sides 112, 114 extend a first width 124 in a thickness direction T transverse to the longitudinal direction L. The long sides 108, 110 extend a height 128 in a height direction H transverse to the longitudinal direction L and the thickness direction T. The groove 66 has a groove width 92, a groove height 94, and a groove depth 95. The first width 124 is substantially equal to the groove width 92, and the first portion 118 causes the first width 124 to be at least partially disposed within the groove depth 95 during operation of the pump 30. Using the recess 122 of the present invention, the contact at the interface between the first portion 118 and the groove 64 is reduced by about 50% in one example.

[0059] Each vane 66 received in a corresponding one of the slots 66 extends a length from a first end 118 to a second end 120 in the longitudinal direction L. The first end 118 is received in its corresponding slot 66 and the second end 120 has a tip 116 that engages the outer peripheral wall of the hole 62 .

[0060] In order to reduce sticking between the blade 66 and the rotor slot 64, one or more recesses 122 are provided on at least one of the first surface 104 and the second surface 106. The recess 122 has a second width 126 in the thickness direction T, which provides an effective depth for collecting any condensed vapor. The second width 126 corresponding to the thickness of the blade 66 at the recess 122 is less than the first width 124. In the example described, the recess 122 extends to the end 116 of the second portion 120. Centrifugal force gathers liquid from the interface between the rotor 52 and the first portion 118 of the blade 66 so that it can be discharged from these mating surfaces to the end 116 and out of the outlet of the pump. The wall 130 having the first width 124 and extending the entire height 128 of the blade 66 in the height direction H prevents leakage from passing over the blade in the slot 64.

[0061] In the example, the rotor 52 and the blades 66 are constructed of a plastic material suitable for the application. In one example, the recesses 102, 122 are defined by a molded surface that is structurally identifiable and different from other types of surfaces (e.g., machined surfaces). Coatings may be added to the recesses 102 and / or 122 to enhance liquid shedding from the surface if desired. The geometry of the recesses 102, 122 may vary depending on the materials used, pump speed, pressure, and application.

[0062] In operation, the controller 40 communicates with the pump 30 to maintain pressure on the system. The evaporative emission system 10 operates the pump 30 substantially without viscosity, enabling the pump 30 to reach the desired pressure for leak testing.

[0063] It should also be understood that although a specific component arrangement is disclosed in the illustrated embodiment, other arrangements will also benefit from it. Although a specific order of steps is shown, described and claimed, it should be understood that unless otherwise indicated, these steps can be performed in any order, can be separated or combined and will still benefit from the present invention.

[0064] Although different examples have specific components shown in the figures, the embodiments of the present invention are not limited to these specific combinations. Some components or features of one example may be used in combination with features or components of another example.

[0065] Although example embodiments have been disclosed, one of ordinary skill in the art would recognize that certain modifications would fall within the scope of the claims. Therefore, the following claims should be studied to determine their true scope and content.

Claims

1. A vane pump, comprising: a housing providing an aperture in fluid communication with the inlet passage and the outlet passage; a rotating assembly disposed within the bore and configured to rotate relative to the bore, The rotating assembly comprises: a rotor mounted on the shaft and having a plurality of slots, the rotor having a first face portion and a second face portion engaged with the housing; a blade received in each slot, each blade having a first surface and a second surface extending in a longitudinal direction a length from a first end to a second end, the first end being received in its respective slot, and The rotating assembly includes a recessed portion located on at least one of the first face portion, the second face portion, the first surface of the first end portion, and the second surface of the first end portion, wherein a plurality of recessed portions are provided on each blade.

2. The vane pump according to claim 1, wherein: Each vane comprises a substantially rectangular cross-section provided by spaced apart long sides in conjunction with spaced apart short sides, the long sides being provided by the first surface and the second surface, and at least one of the plurality of recesses is provided on at least one of the first surface and the second surface.

3. The vane pump according to claim 2, wherein: The short side extends a first width in a thickness direction transverse to the longitudinal direction, the long side extends in a height direction transverse to the longitudinal direction and the thickness direction, and at least one of the plurality of recesses has a second width in the thickness direction that is smaller than the first width.

4. The vane pump according to claim 3, wherein: The slot has a slot width, a slot height, and a slot depth, the first width being substantially equal to the slot width, and the first portion causing the first width to be at least partially disposed within the slot depth during operation of the vane pump.

5. The vane pump according to claim 1, wherein: The other of the recessed portions is provided on at least one of the first surface portion and the second surface portion.

6. The vane pump according to claim 1, wherein: The first face portion and the second face portion are each bounded by a peripheral portion, and the other of the recessed portions is completely contained within the peripheral portion.

7. The vane pump according to claim 1, wherein: The rotor and the blades are plastic, and the plurality of recesses are defined by a molded surface.

8. The vane pump of claim 1, comprising a motor connected to the rotating assembly via the shaft.

9. A vane pump comprising: a housing providing an aperture in fluid communication with the inlet passage and the outlet passage; a rotating assembly disposed within the bore and configured to rotate relative to the bore, The rotating assembly comprises: a rotor mounted on the shaft and having a plurality of slots, the rotor having a first face portion and a second face portion engaged with the housing; a blade received in each slot, each blade having a first surface and a second surface extending in a longitudinal direction a length from a first end to a second end, the first end being received in its respective slot, and The rotating assembly includes a recessed portion disposed on at least one of the first face portion, the second face portion, the first surface of the first end portion, and the second surface of the first end portion, wherein the recessed portion extends to a distal end of the second end portion.

10. The vane pump according to claim 9, wherein: At least one recess is provided on each of the first surface and the second surface.

11. An evaporative emission system comprising the vane pump according to claim 1, comprising: a fuel system including a fuel tank and a carbon canister, the fuel system containing vapor; at least one valve which is set in a closed position during a leak detection procedure, The vane pump includes a motor connected to a rotating assembly via a shaft, and A controller is in communication with the pump, the controller being configured to maintain pressure on a system having the vane pump during a leak testing procedure, the rotating assembly being configured to collect vapor in the recess during operation.

12. A vane pump comprising: a housing providing an aperture in fluid communication with the inlet passage and the outlet passage; a rotating assembly disposed within the bore and configured to rotate relative to the bore, The rotating assembly comprises: a rotor mounted on the shaft and having a plurality of slots, the rotor having a first face portion and a second face portion engaged with the housing; a blade received in each slot, each blade having a first surface and a second surface extending in a longitudinal direction a length from a first end to a second end, the first end being received in its respective slot, and wherein the rotating assembly includes a recessed portion provided on at least one of the first face portion, the second face portion, the first surface of the first end portion, and the second surface of the first end portion, wherein each blade includes a substantially rectangular cross-section provided by spaced apart long sides in conjunction with spaced apart short sides, the long sides being provided by the first surface and the second surface, and the recessed portion is provided on at least one of the first surface and the second surface, wherein the short sides extend a first width in a thickness direction transverse to the longitudinal direction, the long sides extend in a height direction transverse to the longitudinal direction and the thickness direction, and the recessed portion has a second width in the thickness direction that is smaller than the first width, The groove has a groove width, a groove height, and a groove depth, the first width is substantially equal to the groove width, and the first end causes the first width to be at least partially disposed within the groove depth during operation of the vane pump.

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