Fuel vapor pump assembly and fuel evaporative emission control system including the same

Abstract

The present invention relates to a fuel vapor pump assembly and a fuel evaporation emission control system including the same. The fuel vapor pump assembly (100) can be used to pump gas containing fuel vapor from a fuel vapor adsorption device to a fuel vapor receiving device, and includes a pump portion (50) and a valve portion (80) connected to each other. The valve portion is configured as a switch valve that can be switched between an open position and a closed position without implementing a flow regulation function. In the open position, the valve portion (80) allows the gas to be pumped by the pump portion (50) through the fuel vapor pump assembly (100), while in the closed position, the valve portion (80) prevents the gas from passing through the fuel vapor pump assembly (100).

Description

Technical Field

[0001] The present invention relates to the field of pumps, and more particularly to a fuel vapor pump assembly for desorbing fuel vapor from a carbon canister, particularly in an evaporative emission control (EVAP) system of an automobile. The present invention also relates to an EVAP system including such a fuel vapor pump assembly. Background Art

[0002] During operation, a car engine burns fuel, such as gasoline, in the fuel tank to generate energy to propel the vehicle. Fuel easily evaporates and releases fuel vapor, which not only pollutes the environment but also reduces fuel economy. Currently, most cars use evaporative emission control (EVAP) systems to recover and reuse fuel vapor, preventing it from escaping into the atmosphere and potentially negatively impacting the environment, while also improving fuel economy.

[0003] The EVAP system primarily consists of a fuel tank containing, for example, gasoline, a canister for absorbing and recovering fuel vapor from the fuel tank, a desorption valve (also known as a "purge valve") for controlling the amount of fuel vapor desorbed from the canister, and related gas connection piping. The desorption valve is typically connected between the canister and the engine's intake (e.g., the intake manifold). When the engine is running, the vacuum generated in the engine's intake draws gas containing fuel vapor from the canister through the open desorption valve into the engine, thereby desorbing and regenerating the canister. However, the engine's intake may not always generate sufficient desorption vacuum, resulting in an inability to draw sufficient gas from the canister into the engine. Therefore, existing EVAP systems employ an active desorption pump (also known as a "purge / scavenger pump") connected between the canister and the engine's intake to provide power to actively draw gas containing fuel vapor from the canister, thereby maintaining the sufficient pressure differential and flow required for desorption even outside the engine's operating environment.

[0004] When a desorption pump is provided, a desorption valve is typically connected downstream of the pump and is configured as a precisely controllable solenoid valve, thereby regulating the flow of gas pumped by the pump. However, existing technologies suffer from the following issues: Desorption valves are noisy and have a short service life. For example, noise reduction features increase leakage paths, leading to significant pressure loss in the pipeline. The desorption pump and valve occupy excessive space, require numerous connecting pipes, and are complex to install, resulting in high costs. Summary of the Invention

[0005] The purpose of the present invention is to solve the above-mentioned problems and / or other defects in the prior art.

[0006] The present invention is based on the following findings of the inventors: For some hybrid vehicles and extended-range vehicles, the engine is running for a limited time; thus, in order to fully complete the task of desorbing fuel vapor from the carbon canister to the intake part of the engine, it is often necessary to adjust the desorption pump to the maximum head within the limited engine running time, and at the same time adjust the desorption valve to the maximum flow state to achieve the maximum flow of pumped gas, or adjust the flow of pumped gas by adjusting the speed of the desorption pump when the desorption valve is adjusted to the maximum flow state, so as to complete the desorption as quickly as possible; it can be seen that in these cases, the desorption valve does not play its function of accurately regulating the flow, and the desorption valve is an over-design that does not match its function. Based on the above understanding, the present invention conceives the following technical solutions to solve one or more problems existing in the prior art.

[0007] According to one aspect of the present invention, a fuel vapor pump assembly is provided. The assembly is configured to pump gas containing fuel vapor from a fuel vapor adsorption device to a fuel vapor receiving device, and includes a pump portion and a valve portion connected to each other. The valve portion is configured as an on-off valve that is switchable between an open position and a closed position without performing a flow regulation function. In the open position, the valve portion allows the gas to be pumped through the fuel vapor pump assembly by the pump portion, while in the closed position, the valve portion prevents the gas from passing through the fuel vapor pump assembly.

[0008] According to an exemplary embodiment of the present invention, the pump portion and the valve portion may share a pump assembly housing formed as one body.

[0009] According to an exemplary embodiment of the present invention, the pump assembly housing may be a one-piece injection molded part.

[0010] According to an exemplary embodiment of the present invention, the switching valve may be an electromagnetically controlled switching valve.

[0011] According to an exemplary embodiment of the present invention, the pump portion may include a pump impeller, a motor driving the pump impeller to rotate, and a control unit controlling a rotation speed of the motor.

[0012] According to an exemplary embodiment of the present invention, the pump assembly housing may be provided with an electrical interface and / or a mounting interface shared by the pump part and the valve part.

[0013] According to an exemplary embodiment of the present invention, the pump portion may be provided with an air inlet for the gas to enter the fuel vapor pump assembly, and the valve portion may be provided with an air outlet for the gas to exit the fuel vapor pump assembly.

[0014] According to another aspect of the present invention, a fuel evaporative emission control system is provided, comprising the fuel vapor pump assembly described above and a charcoal canister serving as the fuel vapor adsorbing device. The fuel vapor pump assembly is connected between the charcoal canister and the fuel vapor receiving device to pump gas containing fuel vapor from the charcoal canister to the fuel vapor receiving device.

[0015] According to an exemplary embodiment of the present invention, the fuel vapor receiving device may be an intake portion of a vehicle engine system, such as an intake manifold.

[0016] According to an exemplary embodiment of the present invention, the valve portion of the fuel vapor pump assembly can be configured to be in the open position when the vehicle engine system is operating and in the closed position when the vehicle engine system is not operating when desorbing fuel vapor from the charcoal canister.

[0017] The fuel vapor desorption solution according to the present invention achieves at least one of the following beneficial effects: Because existing flow-adjustable desorption valves fail to fully function as flow regulators, they are replaced with on-off valves that can switch between open and closed positions but lack precise flow regulation. This significantly simplifies the structure of the desorption valve, reduces valve lifespan requirements, and reduces costs. It also addresses the high noise and wear issues associated with frequent on-off switching of existing electromagnetic desorption valves to implement flow regulation. Furthermore, given the simple structure of the on-off valve, the present invention integrates it with a desorption pump to form a pump assembly comprising a valve portion and a pump portion, wherein the valve and pump portions share a housing, electrical interfaces, and / or mounting interfaces. This reduces installation space, accessories (such as wiring harnesses), and labor required to separately install the desorption valve and pump, thereby reducing equipment costs, compared to solutions with separate desorption valves and pumps. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will now be described in detail by way of non-limiting examples with reference to the accompanying drawings, which are schematic only and not necessarily drawn to scale. Furthermore, they illustrate only those parts necessary to illustrate the present invention, while other parts may be omitted or mentioned only briefly. That is, in addition to the parts or elements shown in the drawings, the present invention may also include other parts or elements. In the drawings:

[0019] Figure 1 is a schematic diagram of an EVAP system according to the prior art;

[0020] Figure 2 is a schematic diagram of an EVAP system according to an exemplary embodiment of the present invention;

[0021] Figure 3is a perspective view of a fuel vapor pump assembly according to an exemplary embodiment of the present invention as viewed from one angle;

[0022] Figure 4 yes Figure 3 A perspective view of the fuel vapor pump assembly shown from another angle;

[0023] Figure 5 yes Figure 3 A top view of the fuel vapor pump assembly is shown. DETAILED DESCRIPTION

[0024] Below, with reference to the accompanying drawings, exemplary embodiments according to the present invention are described in detail. In the following description, many specific details are set forth so that those skilled in the art can more fully understand the present invention. However, it will be apparent to those skilled in the art that the present invention may be implemented without some of these specific details. In addition, it should be understood that the present invention is not limited to the specific embodiments described. On the contrary, any combination of the features and elements described herein may be considered to implement the present invention, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments, and advantages are for illustrative purposes only and should not be considered as elements or limitations of the claims, unless expressly set forth in the claims.

[0025] Figure 1 The basic structure of an EVAP system according to prior art is schematically illustrated. The EVAP system is shown to include a canister 1 for adsorbing and recovering fuel vapor from a vehicle's fuel tank (the canister 1 can thus be considered a fuel vapor adsorption device), a desorption valve 3 for controlling the amount of fuel vapor desorbed from the canister 1, and an active desorption pump 2 connected between the canister 1 and the desorption valve 3. In the illustrated exemplary structure, the desorption valve 3 is connected to a turbocharger 5 mounted on the vehicle via a check valve 4. The turbocharger 5 is in turn connected to an intake portion (such as an intake manifold) 7 of the vehicle's engine system via an electronic throttle control module (ETC) 6 (the intake portion can thus be considered a fuel vapor receiving device). Of course, for vehicles not equipped with a turbocharger, the check valve 4 can be connected directly to the ETC 6. The desorption valve 3 is in the form of a solenoid valve with precisely controllable flow, thereby adjusting the fuel vapor desorption flow rate. During active desorption, the desorption valve 3 is adjusted to an appropriate flow rate, and the desorption pump 2 is activated. As shown by the blank arrows in the figure, the gas containing fuel vapor is pumped from the carbon canister 1 through the desorption valve 3, the check valve 4, the turbocharger 5, and the ETC 6 to the intake manifold 7, thereby completing the desorption of the carbon canister 1. As mentioned above, this existing desorption solution has problems such as high noise and wear of the desorption valve, and the large space occupied by the desorption pump and desorption valve, as well as cumbersome installation.

[0026] Figure 2The EVAP system according to an exemplary embodiment of the present invention is schematically shown. Figure 1 The EVAP system shown is different only in that a fuel vapor pump assembly 100 according to an exemplary embodiment of the present invention is used instead of the conventional EVAP system. Figure 1 The desorption pump 2 and the desorption valve 3 are shown separately arranged, so that the fuel vapor pump assembly 100 is also connected between the carbon canister 1 and the intake part 7 of the vehicle engine system, and can pump the gas containing fuel vapor from the carbon canister 1 to the intake part 7.

[0027] Figures 3 to 5 The specific configuration of a fuel vapor pump assembly 100 according to an exemplary embodiment of the present invention is shown. The fuel vapor pump assembly 100 includes a pump portion 50 and a valve portion 80 connected to each other. For example, the pump portion 50 and the valve portion 80 may share a single, integral pump assembly housing. More specifically, the pump portion 50 may include a pump housing and pump operating components housed therein, while the valve portion 80 may include a valve housing and valve operating components housed therein. The pump housing may include a pump body 54 and a pump housing cover 53 covering it, while the valve housing may include a valve body 84 and a valve housing cover 83 covering it. The pump body 54 and the valve body 84 may be integrally formed (e.g., as a single-piece injection molded part) to form one portion of the pump assembly housing, while the pump housing cover 53 and the valve housing cover 84 may also be integrally formed (e.g., as a single-piece injection molded part) to form another portion of the pump assembly housing. Thus, the fuel vapor pump assembly according to the present invention is constructed by integrating the desorption valve and the desorption pump.

[0028] The integration of the desorption valve and the desorption pump in the present invention is based on the simplified structure of the desorption valve compared to the prior art. Specifically, the prior art electromagnetic desorption valve 3 with adjustable flow rate requires the application of a specific pulse signal to control the valve's operating element to frequently open and close in a short period of time in order to precisely regulate the flow rate. This generates significant noise and wear, necessitating the inclusion of noise reduction features. This control method and operating mode results in a complex and bulky structure for the desorption valve. In contrast, the valve portion 80 in the fuel vapor pump assembly 100 according to the present invention is configured as an on-off valve that can be switched between open and closed positions without requiring precise flow rate regulation. In other words, the on-off valve can remain in the open position for extended periods, allowing gas containing fuel vapor to be pumped through the fuel vapor pump assembly 100 by the pump portion 50, while preventing the gas from passing through the fuel vapor pump assembly 100 when in the closed position. For ease of control, the valve portion 80 can be configured, for example, as an electromagnetically controlled on-off valve, in which the valve's operating element moves under the influence of electromagnetic force by energizing and de-energizing the valve to open and close. Of course, the present invention is not limited to this, and an on-off valve that opens and closes in other control modes but does not regulate flow can also be used. As can be seen, the "on-off valve" used in the present invention means that the valve operating element in the valve portion 80 configured as an on-off valve has two operating states: open and closed, rather than frequently opening and closing in a short period of time to regulate flow, as in existing electromagnetic desorption valves. This reduces the generation of significant noise and wear in the valve portion 80, eliminating the need for noise reduction features, simplifying the structure, and reducing size.

[0029] Although the valve portion 80 in the present invention does not precisely regulate the flow rate, this does not pose a problem for some hybrid vehicles and extended-range vehicles. This is because the engine operation time of such vehicles is limited. Therefore, in order to complete the fuel vapor desorption task as quickly and fully as possible, it is generally required to adjust the desorption pump to maximum head and the desorption valve to maximum flow state within the limited engine operation time to achieve the maximum flow rate of pumped gas, or to adjust the flow rate of pumped gas by adjusting the speed of the desorption pump when the desorption valve is adjusted to maximum flow state. In other words, in these cases, the valve portion 80 used as the desorption valve does not actually need to have a flow regulation function, but only needs to be able to switch between two operating states: open and closed. In the present invention, since the electromagnetic desorption valve with adjustable flow is replaced with an on-off valve that only needs to be opened and closed, the structure of the desorption valve is simplified, the cost is reduced, and the problems of high noise and high wear caused by the frequent opening and closing of the existing electromagnetic desorption valve due to the flow regulation function are avoided.

[0030] The pump section 50 includes a rotatable pump impeller as the main working element, a motor that drives the pump impeller to rotate, and a control unit that controls the motor's speed. These elements are housed in a cavity surrounded by a pump housing 53 and a pump housing 54. An inlet pipe 52 is provided on the pump housing 53, which defines an air inlet 51 for allowing gas containing fuel vapor to enter the pump assembly. The rotation axis of the pump impeller can be coaxial with the central axis of the inlet pipe 52, so that when the pump impeller rotates, the gas is sucked in by the pump impeller through the air inlet 51 and eventually discharged as shown in FIG. Figure 3 and 5 As shown in FIG, the flow channel / air channel / channel along the pump housing 53 of the impeller reaches the outlet portion 55 of the flow channel / air channel / channel of the pump housing 53 (the outlet portion 55 is also the outlet pipe of the pump portion 50). The outlet portion 55 is connected to the valve housing 83, whereby the gas driven by the impeller blades is passed along the outlet portion 55 into the valve portion 80 (the outlet pipe of the pump portion 50 is reused as the inlet pipe of the valve portion 80). When the valve operating element housed in the valve portion is in the open position, it leaves the pump assembly through the outlet pipe 82 provided on the valve housing 83 and defining the gas outlet 81 and continues to be transmitted downstream. It should be noted that although the valve portion 80 does not regulate the flow of the pumped gas in the present invention, the gas flow rate can still be adjusted by controlling the impeller rotation speed in the pump portion 50 when necessary.

[0031] In the present invention, the pump part 50 and the valve part 80 are integrated together and share the pump assembly housing. On this basis, further, the pump part and the valve part can also share various interfaces required for their operation. For example, the pump part 50 and the valve part 80 can share the electrical interface 60, so that they can be powered and / or communicate with the outside (such as transmitting control signals, etc.) in a centralized and unified manner, saving the wiring harness cost and wiring manpower required for power supply and communication separately. The pump part 50 and the valve part 80 can also share a unified installation interface 70, thereby saving the hardware and manpower costs of separately installing the desorption pump and desorption valve.

[0032] In accordance with Figure 2In the EVAP system of the illustrated embodiment, when desorbing fuel vapor from the charcoal canister 1, the valve portion (on-off valve) of the fuel vapor pump assembly 100 can be configured to be in an open position when the vehicle's engine system is operating. In this case, gas containing fuel vapor is pumped by the pump portion of the fuel vapor pump assembly 100 through the open valve portion at its maximum flow rate to the vehicle's engine system's intake, thereby rapidly desorbing the charcoal canister. This is particularly suitable for hybrid vehicles and extended-range vehicles with limited engine operating time. On the other hand, when the vehicle's engine system is not operating, its intake portion cannot be used to desorb the charcoal canister. In this case, the valve portion of the fuel vapor pump assembly 100 can naturally be in a closed position, and the pump portion is not operating. Thus, compared to the complex desorption valves of the prior art that precisely adjust the flow rate, the fuel vapor pump assembly of the present invention achieves the same desorption effect using a simple on-off valve. Furthermore, the integration of the on-off valve and the pump portion achieves the aforementioned technical benefits, significantly improving the cost-effectiveness of the desorption process. Incidentally, when the canister 1 is not required to desorb the fuel vapor, the valve portion 80 may be controlled to open and close according to other needs to perform other functions, such as leak detection.

[0033] Those skilled in the art will appreciate that the embodiments described above are exemplary and that they may be improved upon. The various elements described in the embodiments may be freely combined without causing any conflict in structure or principle.

[0034] After describing the preferred embodiments of the present invention in detail, those skilled in the art will clearly understand that various changes and improvements can be made without departing from the scope and spirit of the protection of the appended claims, and the present invention is not limited to the embodiments described in the specification.

Claims

1. A fuel vapor pump assembly (100) capable of pumping gas containing fuel vapor from a fuel vapor adsorption device to a fuel vapor receiving device, comprising a pump portion (50) and a valve portion (80) connected to each other, wherein: The valve portion is configured as an on-off valve capable of switching between an open position and a closed position without implementing a flow regulation function. In the open position, the valve portion (80) allows the gas to be pumped by the pump portion (50) through the fuel vapor pump assembly (100), while in the closed position, the valve portion (80) prevents the gas from passing through the fuel vapor pump assembly (100). The pump portion (50) and the valve portion (80) share a pump assembly housing that is formed as an integral whole.

2. The fuel vapor pump assembly (100) according to claim 1, characterized in that: The pump assembly housing is a one-piece injection molded part.

3. The fuel vapor pump assembly (100) according to claim 1, characterized in that The switch valve is an electromagnetically controlled switch valve.

4. The fuel vapor pump assembly (100) according to claim 3, characterized in that: The pump portion (50) includes a pump wheel, a motor for driving the pump wheel to rotate, and a control unit for controlling the rotation speed of the motor.

5. The fuel vapor pump assembly (100) according to claim 4, characterized in that: The pump assembly housing is provided with an electrical interface (60) and / or a mounting interface (70) shared by the pump part (50) and the valve part (80).

6. The fuel vapor pump assembly (100) according to any one of claims 1 to 5, characterized in that: The pump portion (50) is provided with an air inlet (51) for the gas to enter the fuel vapor pump assembly, and the valve portion (80) is provided with an air outlet (81) for the gas to leave the fuel vapor pump assembly.

7. A fuel evaporative emission control system, characterized in that include: A fuel vapor pump assembly (100) according to any one of claims 1 to 6; and A carbon canister (1) serving as the fuel vapor adsorption device, The fuel vapor pump assembly (100) is connected between the carbon canister (1) and the fuel vapor receiving device to pump gas containing fuel vapor from the carbon canister to the fuel vapor receiving device.

8. The fuel evaporative emission control system according to claim 7, characterized in that: The fuel vapor receiving device is an intake portion (7) of a vehicle engine system.

9. The fuel evaporative emission control system according to claim 8, characterized in that: The valve portion (80) of the fuel vapor pump assembly (100) is configured to be in the open position when the vehicle engine system is operating and in the closed position when the vehicle engine system is not operating, when desorbing fuel vapor from the charcoal canister (1).

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