WO2017074985A1

WO2017074985A1 - Fuel vapor recovery system

Info

Publication number: WO2017074985A1
Application number: PCT/US2016/058752
Authority: WO
Inventors: Robert Philip Benjey; Thomas Joseph Stoltz
Original assignee: Eaton Corporation
Priority date: 2015-10-26
Filing date: 2016-10-26
Publication date: 2017-05-04

Abstract

A fuel vapor recovery system includes a fuel vapor storage container configured to receive a fuel vapor from a fuel tank, a vapor fuel line coupled to the fuel vapor storage container, the vapor fuel line configured to be fluidly coupled to an intake manifold of a vehicle engine, and a fuel vapor pump coupled to the vapor fuel line and configured to pump the fuel vapor from the fuel vapor storage container to the intake manifold. The fuel vapor pump is configured to be driven by a fuel flow from the fuel tank to the engine.

Description

FUEL VAPOR RECOVERY SYSTEM

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application

Nos. 62/246,220, filed October 26, 2015 and 62/408,861 filed on October 17, 2016, the contents of which are incorporated herein by reference thereto.

FIELD

[0002] The present disclosure relates generally to a fuel vapor recovery system for a vehicle and, more particularly, to a fuel vapor recovery system having a fuel flow powered vapor pump.

BACKGROUND

[0003] Some vehicles may be equipped with a fuel vapor recovery system to capture and store vaporized hydrocarbons released from a fuel tank, for example, during refueling. The vaporized hydrocarbons may be stored in a fuel vapor storage canister packed with an adsorbent such as charcoal or carbon. At a later time when the vehicle engine is in operation, the fuel vapor recovery system may use a vacuum or pressure to purge the vapors into an intake manifold of the engine for use as fuel. The purge flow vacuum or pressure may be generated by one or more pumps and/or ejectors or by pressures in in the engine intake manifold.

[0004] However, it can be difficult purge the vapor storage canister without intake manifold vacuum that can occur with highly boosted engines. Further, pressure fluctuation in the fuel vapor recovery system between vacuum and pressure may affect engine emission performance. Accordingly, while known systems function for their intended purposes, it is desirable to provide an improved fuel vapor recovery system.

[0005] The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

SUMMARY

[0006] In one aspect, a fuel vapor recovery system is provided. The system includes a fuel vapor storage container configured to receive a fuel vapor from a fuel tank, a vapor fuel line coupled to the fuel vapor storage container, the vapor fuel line configured to be fluidly coupled to an intake manifold of a vehicle engine, and a fuel vapor pump coupled to the vapor fuel line and configured to pump the fuel vapor from the fuel vapor storage container to the intake manifold. The fuel vapor pump is configured to be driven by a fuel flow from the fuel tank to the engine.

[0007] In addition to the foregoing, the described fuel vapor recovery system may include one or more of the following features: wherein the fuel vapor pump includes a hydraulic motor coupled to a centrifugal pump; wherein the hydraulic motor is configured to couple to a liquid fuel line between the fuel tank and the engine, the hydraulic motor driven by a flow of fuel in the liquid fuel line; wherein the centrifugal pump is coupled to the vapor fuel line and is configured to pump fuel vapor between the fuel vapor storage container and the intake manifold; a step up gear train coupled between the hydraulic motor and the centrifugal pump; a bypass conduit coupled to the vapor fuel line and configured to bypass the fuel vapor pump; wherein the bypass conduit includes a bypass check valve configured to manage fuel vapor flow through the bypass conduit; wherein the bypass conduit includes a regulator valve configured to manage fuel vapor flow through the bypass conduit; wherein the regulator valve includes a diaphragm and a spool, the spool configured to move between a closed position and an open position; and wherein the regulator valve further includes a pressure line coupled between the diaphragm and the intake manifold.

[0008] In another aspect a vehicle is provided. The vehicle includes an engine having an intake manifold, a fuel tank assembly, and a fuel vapor recovery system. The fuel vapor recovery system includes a fuel vapor storage container configured to receive a fuel vapor from the fuel tank assembly, a vapor fuel line coupled between the fuel vapor storage container and the intake manifold, and a liquid fuel line coupled between the fuel tank assembly and the engine. A fuel vapor pump is coupled to the vapor fuel line and the liquid fuel line, the fuel vapor pump configured to be driven by a fuel flow in the liquid fuel line to pump the fuel vapor from the fuel vapor storage container to the intake manifold.

[0009] In addition to the foregoing, the described vehicle may include one or more of the following features: wherein the fuel vapor pump includes a hydraulic motor coupled to a centrifugal pump; wherein the hydraulic motor is configured to couple to a liquid fuel line between the fuel tank and the engine, the hydraulic motor driven by a flow of fuel in the liquid fuel line; wherein the centrifugal pump is coupled to the vapor fuel line and is configured to pump fuel vapor between the fuel vapor storage container and the intake manifold; a step up gear train coupled between the hydraulic motor and the centrifugal pump; a bypass conduit coupled to the vapor fuel line and configured to bypass the fuel vapor pump; wherein the bypass conduit includes a bypass check valve configured to manage fuel vapor flow through the bypass conduit; wherein the bypass conduit includes a regulator valve configured to manage fuel vapor flow through the bypass conduit; wherein the regulator valve includes a diaphragm and a spool, the spool configured to move between a closed position and an open position; and wherein the regulator valve further includes a pressure line coupled between the diaphragm and the intake manifold.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0011] FIG. 1 is a schematic view of an example fuel vapor recovery system in accordance with the principles of the present disclosure;

[0012] FIG. 2 is a schematic view of another example fuel vapor recovery system in accordance with the principles of the present disclosure; and

[0013] FIG. 3 is a perspective view of an example fuel vapor pump that may be used in the systems shown in FIGS. 1 and 2 in accordance with the principles of the present disclosure.

DETAILED DESCRIPTION

[0014] With initial reference to FIG. 1 , an example fuel vapor recovery system 10 is shown. In the illustrated example, the fuel vapor recovery system 10 is for a vehicle (not shown) such as an automobile having a fuel tank assembly 12 and an internal combustion engine 14 that can have a throttle 16 and an intake manifold 18. However, it will be appreciated that the fuel vapor recovery system 10 may be utilized with various other systems or vehicles.

[0015] As discussed herein in detail, the fuel vapor recovery system 10 can generally include a fuel vapor storage canister 20, a fuel vapor pump 22, a pressure sensor 24, a purge or vapor fuel line 26, and a liquid fuel line 28.

[0016] In the illustrated example, the fuel tank assembly 12 can include a fuel tank 30 having a fuel pump assembly 32, which may include one or more pumps for pressurizing and supplying fuel to fuel injectors (not shown) of the engine 14. Vapors generated in fuel tank 30, for example during refueling, may be directed to the storage canister 20 via a conduit 34. The fuel vapors stored in the storage canister 20 may subsequently be purged to the intake manifold 18 during a purging operation. During the purging operation, a purge valve 36 (e.g., a pulse width modulation solenoid) is opened and air is drawn through an intake conduit 38. As such, the stored fuel vapor is directed by the fuel vapor pump 22 through vapor fuel line 26 to the engine intake manifold 18.

[0017] With reference to FIG. 3, the fuel vapor pump 22 may include a hydraulic motor 40, a gear train 42, and a centrifugal pump 44. The hydraulic motor 40 is operably associated with the liquid fuel line 28 and is operated by hydraulic pressure and the flow of fuel from the fuel tank 30 to the engine 14. Gear train 42 (e.g., a step up gear train) transfers motion or torque from the hydraulic motor 40 to drive an impeller (not shown) of the centrifugal pump 44. As such, the vapor pump 22 utilizes fuel flow to the engine 14 to power the high volume, low pressure pump 44. In this way, the fuel flow in fuel line 28 drives the pump impeller, which facilitates flow of fuel vapor from the vapor canister 20 to the engine 14.

[0018] In the example implementation, fuel vapor recovery system 10 can maintain positive pressure at the purge valve 36 and may be set at a pressure higher than engine intake manifold pressure, thereby enabling highly boosted engines (e.g., turbochargers, superchargers, etc.) to have purge flow when boosting (e.g., producing charge air with a turbocharger compressor). The pressure in manifold 18 can change from a vacuum state to a pressure state relative to atmospheric pressure when boosting occurs. This can happen when the engine power demand goes up and the engine speed also increases to meet power demand. As a result, the fuel flow rate also increases to meet the demand, which increases the liquid fuel flow rate through the hydraulic motor 40. This can result in generating higher pressure in the vapor purge line 26 to enable a continued supply the purge vapor to the now pressurized intake manifold 18.

[0019] Because the liquid fuel is supplied through line 28 during both boost and without boost, the vapor flow may exceed the driven flow of vapor pump 22 under some conditions. Accordingly, system 10 includes a bypass conduit 48 (FIG. 1) configured to receive excess vapor flow, for example, when manifold vacuum exists. The bypass conduit 48 can include a regulator valve 50, for example, to manage vapor flow from the vapor canister 20 to the purge valve 36. In one example, regulator valve 50 can be a check valve.

[0020] During operation, when the vehicle is running, liquid fuel is pumped via the pump assembly 32 through line 28 to the engine 14. This flow rate can be used to drive the hydraulic motor 40, which drives the vapor pump 22. As the flow rate increases, the engine 14 is often boosting and the manifold 18 is pressurized. Liquid flow can drive the pump impeller to pump vapor from the vapor canister 20 to the engine 14 via the purge line 26 and purge valve 36, thereby providing flow even under boost conditions.

[0021] When the manifold 18 is in vacuum, the vapor flow occurs when the purge valve 36 is opened and the regulator valve 50 opens. Thus, purge can occur regardless of manifold pressure conditions. To optimize purge vapor flow, a step up gear ratio 42 can be utilized to increase the speed of the hydraulic motor 40 output in the fuel flow path high enough for the centrifugal pump 44 to operate properly. However, it will be appreciated that other types of pumps and motor combinations may be utilized.

[0022] FIG. 2 illustrates another example fuel vapor recovery system 100 for a vehicle having a fuel tank assembly 1 12 and an internal combustion engine 114. In the example embodiment, engine 114 can be operably associated with a throttle 116, an intake manifold 118, and a boosting device 108 such as a charge air compressor of a turbocharger (not shown). However, it will be appreciated that the fuel vapor recovery system 100 described herein may be utilized with various other systems or vehicles.

[0023] As discussed herein in greater detail, the fuel vapor recovery system 100 can generally include a fuel vapor storage canister 120, a fuel vapor pump 122, a pressure sensor (not shown), a vapor fuel line 126, and a liquid fuel line 128.

[0024] In the illustrated example, fuel tank assembly 112 can include a fuel tank 130 having a fuel pump assembly 132, which may include one or more pumps for pressurizing and supplying fuel to fuel injectors (not shown) of the engine 114. Vapors generated in fuel tank 130, for example during refueling, may be directed to the storage canister 120 via a conduit 134. The fuel vapors stored in the storage canister 120 may subsequently be purged to the intake manifold 118 during a purging operation. During the purging operation, a purge valve 136 (e.g., a pulse width modulation solenoid) is opened and air is drawn through an intake conduit 138. As such, the stored fuel vapor is directed by the fuel vapor pump 122 through vapor fuel line 126 to the engine intake manifold 118.

[0025] With continued reference to FIG. 3, the fuel vapor pump 122 may include a hydraulic motor 140, a gear train 142, and a centrifugal pump 144. The hydraulic motor 40 is operably associated with the liquid fuel line 128 and is operated by the hydraulic pressure and flow of fuel from the fuel tank 130 to the engine 114. Gear train 142 (e.g., a step up gear train) transfers motion or torque from the hydraulic motor 140 to drive an impeller (not shown) of the centrifugal pump 144. As such, the vapor pump 122 utilizes fuel flow to the engine 1 14 to power the high volume, low pressure pump 144. In this way, the fuel flow in fuel line 128 drives the pump impeller, which facilitates a flow of fuel vapor from the vapor canister 120 to the engine 114.

[0026] In the example implementation, fuel vapor recovery system 100 can maintain positive pressure at the purge valve 136 and may be set at a pressure higher than engine intake manifold pressure, thereby enabling highly boosted engines (e.g., turbochargers, superchargers, etc.) to have purge flow when utilizing the boosting device 108. Because the liquid fuel is supplied through line 128 during both boost and without boost, vapor flow may exceed the driven flow of vapor pump 122 under some conditions. Accordingly, system 100 includes a bypass conduit 148 (FiG. 2) configured to receive excess vapor flow, for example, when manifold vacuum is low or pressurized. [0027] In one example, the bypass conduit 148 can include a regulator valve 160 configured to manage vapor flow through the bypass conduit 148. The regulator valve 160 can be a diaphragm-type valve that may include a spool 162, a spool seat 164 having an orifice 166, a spring 168, a diaphragm 170, and a pressure line 172. However, system 100 may utilize various other types of valves that enables the system to function as described herein.

[0028] In the example embodiment, the diaphragm 170 is operably coupled to the pressure line 172 at one end and the other end is coupled to the intake manifold 1 18. As such, the pressure in the intake manifold 118 causes regulator valve 160 to move between an open position and a closed position. Accordingly, the spool 162, which is coupled to the diaphragm 170, moves to the spool seat 164 to the closed position to block orifice 166 when manifold vacuum is low or the manifold is pressurized. The spool 162 is moved to the open position away from the spool seat 164 when a high manifold vacuum occurs. Thus, a vapor flow for bypassing vapor pump 122 can be established through the bypass conduit 148 to pull fuel vapor directly from the vapor canister 120 and/or fuel tank 130.

[0029] As such, during operation, fuel vapor recovery system 100 opens the bypass conduit 148 to bypass the vapor pump 122 when high manifold vacuum occurs. When the purge valve 136 is opened under these conditions, manifold vacuum is applied to the vapor purge line 126, thereby pulling fuel vapor and air through the system 100, which purges fuel vapors from one or more storage beds of the vapor canister 120.

[0030] As the manifold pressure is changed from a vacuum to a positive pressure (e.g., during boosting), the regulator valve 160 closes to increasingly bias the system to a pressurized state. When boost pressure is high (manifold pressure is positive and high) the pump bypass 148 is closed to allow a pressure higher than the manifold pressure, which enables purge to occur via vapor pump 22 with engine boost operating.

[0031] When the vehicle is running, liquid fuel is pumped via the pump assembly 132 through line 128 to the engine 114. This flow rate can be used to drive the hydraulic motor 140, which drives the high flow, low pressure vapor pump 122. As the flow rate increases, the engine 114 is often boosting and the manifold 118 is pressurized. Liquid flow can drive the pump impeller to pump vapor from the vapor canister 120 to the engine 1 14 via a purge line 126 and purge valve 136, thereby providing flow even under boost conditions.

[0032] When the manifold 118 is in vacuum, the vapor flow occurs when the purge valve 36 is opened and the regulator valve 160 opens. Thus, purge can occur regardless of manifold pressure conditions. To optimize purge vapor flow, a step up gear ratio 142 can be utilized to increase the speed of the hydraulic motor 140 in the fuel flow path high enough for the centrifugal pump 144 to operate properly. However, it will be appreciated that other types of pumps and motor combinations may be utilized.

[0033] Described herein are systems and methods for a vehicle fuel vapor recovery system having a vapor fuel pump driven by a fuel flow to the engine. The vapor fuel pump includes a gear train operably disposed between a hydraulic motor and a centrifugal pump. The hydraulic motor, which is driven by a fuel flow to the engine, drives the centrifugal pump via the gear train to thereby pump fuel vapor from a vapor storage canister and/or a fuel tank. A bypass line and associated bypass valve are configured to enable the fuel vapor recovery system to purge fuel vapor during both pressure and vacuum conditions in an intake manifold of the engine.

[0034] The foregoing description of the examples has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular example are generally not limited to that particular example, but, where applicable, are interchangeable and can be used in a selected example, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

CLAIMS What is claimed is:

1. A fuel vapor recovery system comprising:

a fuel vapor storage container configured to receive a fuel vapor from a fuel tank; a vapor fuel line coupled to the fuel vapor storage container, the vapor fuel line configured to be fluidly coupled to an intake manifold of a vehicle engine; and

a fuel vapor pump coupled to the vapor fuel line and configured to pump the fuel vapor from the fuel vapor storage container to the intake manifold, wherein the fuel vapor pump is configured to be driven by a fuel flow from the fuel tank to the engine.

2. The system of claim 1 , wherein the fuel vapor pump includes a hydraulic motor coupled to a centrifugal pump.

3. The system of claim 2, wherein the hydraulic motor is configured to couple to a liquid fuel line between the fuel tank and the engine, the hydraulic motor driven by a flow of fuel in the liquid fuel line.

4. The system of claim 3, wherein the centrifugal pump is coupled to the vapor fuel line and is configured to pump fuel vapor between the fuel vapor storage container and the intake manifold.

5. The system of claim 2, further comprising a step up gear train coupled between the hydraulic motor and the centrifugal pump.

6. The system of claim 1 , further comprising a bypass conduit coupled to the vapor fuel line and configured to bypass the fuel vapor pump.

7. The system of claim 6, wherein the bypass conduit includes a bypass check valve configured to manage fuel vapor flow through the bypass conduit.

8. The system of claim 6, wherein the bypass conduit includes a regulator valve configured to manage fuel vapor flow through the bypass conduit.

9. The system of claim 8, wherein the regulator valve includes a diaphragm and a spool, the spool configured to move between a closed position and an open position.

10. The system of claim 9, wherein the regulator valve further includes a pressure line coupled between the diaphragm and the intake manifold.

1 1. A vehicle comprising:

an engine having an intake manifold;

a fuel tank assembly; and

a fuel vapor recovery system comprising:

a fuel vapor storage container configured to receive a fuel vapor from the fuel tank assembly; a vapor fuel line coupled between the fuel vapor storage container and the intake manifold;

a liquid fuel line coupled between the fuel tank assembly and the engine; and

a fuel vapor pump coupled to the vapor fuel line and the liquid fuel line, the fuel vapor pump configured to be driven by a fuel flow in the liquid fuel line to pump the fuel vapor from the fuel vapor storage container to the intake manifold.

12. The vehicle of claim 11 , wherein the fuel vapor pump includes a hydraulic motor coupled to a centrifugal pump.

13. The vehicle of claim 12, wherein the hydraulic motor is configured to couple to a liquid fuel line between the fuel tank and the engine, the hydraulic motor driven by a flow of fuel in the liquid fuel line.

14. The vehicle of claim 13, wherein the centrifugal pump is coupled to the vapor fuel line and is configured to pump fuel vapor between the fuel vapor storage container and the intake manifold.

15. The vehicle of claim 12, further comprising a step up gear train coupled between the hydraulic motor and the centrifugal pump.

16. The vehicle of claim 10, further comprising a bypass conduit coupled to the vapor fuel line and configured to bypass the fuel vapor pump.

17. The vehicle of claim 16, wherein the bypass conduit includes a bypass check valve configured to manage fuel vapor flow through the bypass conduit.

18. The vehicle of claim 16, wherein the bypass conduit includes a regulator valve configured to manage fuel vapor flow through the bypass conduit.

19. The vehicle of claim 18, wherein the regulator valve includes a diaphragm and a spool, the spool configured to move between a closed position and an open position.

20. The vehicle of claim 19, wherein the regulator valve further includes a pressure line coupled between the diaphragm and the intake manifold.