DE102021112564A1 - EVAPORATIVE EMISSION SYSTEM - Google Patents

Abstract

Evaporative emission control (EVAP) system that collects fuel vapor from a fuel tank, comprising an evaporative emissions (EVAP) canister and a fuel vapor line extending between the fuel tank and the EVAP canister, and a fuel pump assembly disposed in the fuel tank. A vapor-liquid separator removes HC-liquid fuel suspended in the fuel vapor and returns it to a HC-liquid-fuel reservoir of the fuel tank and is in fluid communication with the fuel vapor line to convey the fuel vapor to the EVAP canister.

Description

INTRODUCTION

This disclosure relates to an emissions control system for a motor vehicle, and more particularly to an evaporative emissions purge system for the emissions control system.

Most vehicles powered by an internal combustion engine include an emission control system. An emission control system reduces the regulated emissions associated with the transport and/or combustion of hydrocarbon (HC) based fuels. Emission control systems may include both aftertreatment systems that treat products of combustion and evaporative emission control (EVAP) systems that capture HC-laden fuel vapors generated by liquid HC fuels present in a vehicle's fuel tank and fuel system. Today's vehicles include fuel systems that do not vent directly to the atmosphere. Instead, the fuel systems vent through an evaporative emission control (EVAP) canister that captures the fuel vapor and prevents it from being released into the atmosphere.

EVAP canisters typically contain activated charcoal. Fuel vapor that is in the vehicle's fuel tank can be routed from the tank through the EVAP canister where the activated carbon absorbs and stores the HC fuels suspended in the fuel vapor. Under certain vehicle operating conditions, fresh air is drawn in through the EVAP canister, which pulls the stored HC fuel out of the activated carbon and delivers it to the engine for combustion. This activity regenerates the activated carbon in the EVAP canister and prepares it to store additional HC fuel from fuel vapor generated by fuel in the fuel tank.

Refueling a vehicle creates a significant fuel vapor load in the fuel tank because the liquid fuel entering the fuel tank displaces fuel vapor that is above the level of the liquid fuel. In addition, the fuel entering the tank through the filler pipe will stir up the fuel in the tank, resulting in a higher than normal amount of suspended HC fuel in the fuel vapor. It is desirable to remove as much of the suspended HC fuel in the fuel vapor as possible before directing the fuel vapor to the EVAP canister.

SUMMARY

In an exemplary embodiment, an evaporative emission control (EVAP) system that collects HC-laden fuel vapor (fuel vapor) from a fuel tank includes a fuel tank, an evaporative emissions (EVAP) canister, an evaporative fuel line extending between the fuel tank and the EVAP -Reservoir extends, and arranged in the fuel tank fuel pump assembly. The fuel pump assembly includes a fuel pump and a vapor-liquid separator integral with the fuel pump assembly that removes HC liquid fuel suspended in fuel vapor and returns it to a HC liquid fuel reservoir of the fuel tank and is in fluid communication with the fuel vapor line to deliver fuel vapor to the EVAP canister.

In addition to one or more of the features described herein, the vapor-liquid separator includes a vapor-liquid cyclone separator.

In addition to one or more of the features described herein, the vapor-liquid cyclone separator includes a separator housing having a cylindrical upper portion with a vapor inlet and a vapor outlet and a conical lower portion with a liquid fuel outlet. The vapor inlet opens into the cylindrical top portion in a tangential orientation to induce swirl in the fuel vapor and separate HC liquid fuel therefrom.

In addition to one or more of the features described herein, the HC liquid fuel is collected at the walls of the cylindrical upper portion and returned to the HC liquid fuel reservoir of the fuel tank through the liquid fuel outlet of the conical lower portion.

In addition to one or more features described herein, the vapor-liquid cyclone separator further includes a fuel shut-off riser fluidly connected to the vapor inlet and defining a conduit for entry of fuel vapor into the vapor-liquid cyclone separator.

In addition to one or more features described herein, the fuel pump assembly is a drop-in pump installed in the fuel tank through an opening in the fuel tank.

In addition to one or more of the features described herein, the fuel pump includes pen arrangement further includes a mounting flange arrangement sealingly closing the opening in the fuel tank and supporting the vapor-liquid cyclone separator and the fuel pump therein.

In addition to one or more of the features described herein, the vapor outlet includes a tubular extension having a valve seat disposed therein and a ball valve trapped within the tubular extension between the valve seat and one end thereof to prevent fuel from entering the fuel vapor line and the EVAP - to prevent containers.

In another exemplary embodiment, an evaporative emission control (EVAP) system that collects fuel vapor from a fuel tank includes a fuel tank, an evaporative emissions (EVAP) canister, a fuel vapor line extending between the fuel tank and the EVAP canister, a A fuel pump assembly disposed in the fuel tank, comprising a fuel pump and a vapor-liquid separator that removes liquid HC fuel suspended in the fuel vapor and returns it to a liquid HC fuel reservoir of the fuel tank and is in fluid communication with the fuel vapor line to evacuate the fuel vapor to Promote EVAP canister.

In addition to one or more of the features described herein, the vapor-liquid separator includes a vapor-liquid cyclone separator.

In addition to one or more of the features described herein, the vapor-liquid cyclone separator includes a separator housing having a cylindrical upper portion with a vapor inlet and a vapor outlet and a conical lower portion with a liquid fuel outlet. The vapor inlet opens into the cylindrical top portion in a tangential orientation to induce swirl in the fuel vapor and separate HC liquid fuel therefrom.

In addition to one or more of the features described herein, the HC liquid fuel is collected at the walls of the cylindrical upper portion and returned to the HC liquid fuel reservoir of the fuel tank through the liquid fuel outlet of the conical lower portion.

In addition to one or more features described herein, the vapor-liquid cyclone separator further includes a filler shut-off riser fluidly connected to the vapor inlet and defining a conduit for entry of fuel vapor into the vapor-liquid cyclone separator.

In addition to one or more of the features described herein, the vapor-liquid cyclone separator may be mounted inside the fuel tank on an upper surface thereof.

In addition to one or more of the features described herein, an in-tank fuel vapor line extends from the vapor outlet of the separator housing and is fluidly connected to the fuel vapor line that extends between the fuel tank and the EVAP canister.

In addition to one or more of the features described herein, the vapor outlet includes a tubular extension having a valve seat disposed therein and a ball valve trapped within the tubular extension between the valve seat and one end thereof to prevent fuel from entering the fuel vapor line and the EVAP - to prevent containers.

In another exemplary embodiment, an automotive vehicle includes an internal combustion engine that receives pressurized fuel from a fuel tank via a pressurized fuel line. An evaporative emission control (EVAP) system that collects fuel vapor from the fuel tank includes a fuel tank, an evaporative emissions (EVAP) canister, a fuel vapor line that extends between the fuel tank and the EVAP canister, and a fuel pump assembly that is Fuel tank is arranged. The fuel pump assembly includes a fuel pump and a vapor-liquid separator integral with the fuel pump assembly that removes HC liquid fuel suspended in fuel vapor and returns it to a HC liquid fuel reservoir of the fuel tank and is in fluid communication with the fuel vapor line to deliver fuel vapor to the EVAP canister.

In addition to one or more of the features described herein, the vapor-liquid separator includes a vapor-liquid cyclone separator having a separator housing with a cylindrical top portion including a vapor inlet and a vapor outlet, and a conical bottom portion with a liquid fuel outlet. The vapor inlet opens into the cylindrical upper portion in a tangential orientation to cause swirling of the fuel vapor resulting in separation of the HC liquid fuel therefrom.

In addition to one or more of the features described herein, the fuel pump assembly is a drop-in pump that is installed in the fuel tank through an opening in the fuel tank and further includes a mounting flange assembly that seals the opening in the fuel tank and the vapor-liquid cyclone separator and carries the fuel pump inside.

In addition to one or more of the features described herein, the vapor outlet includes a tubular extension having a valve seat disposed therein and a ball valve trapped within the tubular extension between the valve seat and one end thereof to prevent fuel from entering the fuel vapor line and the EVAP - to prevent containers.

The above features and advantages, as well as other features and advantages of the disclosure are readily apparent from the following detailed description when considered in connection with the accompanying drawings.

character list

• 1 eine Seitenansicht, teilweise in Phantomdarstellung, eines Fahrzeugs mit Merkmalen der Offenbarung zeigt,
• 2 eine schematische Ansicht eines EVAP-Systems mit Merkmalen der Offenbarung zeigt,
• 3 eine schematische Ansicht eines Dampf-Flüssigkeits-Abscheiders mit Merkmalen der Offenbarung zeigt,
• 4 eine Schnittansicht des Dampf-Flüssigkeits-Abscheiders von 3 entlang Linie 4-4 zeigt und
• 5 eine schematische Ansicht einer weiteren Ausgestaltung des EVAP-Systems mit Merkmalen der Offenbarung zeigt.

Other features, advantages and details are set forth in the following detailed description, by way of example only, which detailed description makes reference to the drawings, in which:

• 1 shows a side view, partially in phantom, of a vehicle having features of the disclosure,
• 2 shows a schematic view of an EVAP system with features of the disclosure,
• 3 shows a schematic view of a vapor-liquid separator with features of the disclosure,
• 4 a sectional view of the vapor-liquid separator of FIG 3 shows along line 4-4 and
• 5 12 shows a schematic view of another embodiment of the EVAP system incorporating features of the disclosure.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. Corresponding reference characters throughout the drawings indicate like or corresponding parts and features.

A motor vehicle according to an exemplary embodiment is in 1 illustrated generally at 10. Motor vehicle 10 includes a body 12 and is driven by a prime mover in the form of an internal combustion engine 14 . The engine 14 receives pressurized fuel from a fuel tank 18 via a pressurized fuel line 20 . The motor vehicle 10 is also shown with front 22 and rear 24 wheels. The front and rear wheels 22, 24 are mechanically connected to the internal combustion engine 14, e.g. B. via one or more transmissions (not shown), a transaxle (not shown) or the like.

According to an exemplary embodiment, the motor vehicle 10 includes an evaporative emission control (EVAP) system 30, 2 that collects the HC-laden fuel vapor (fuel vapor) 32 from the vehicle tank 18, stores the hydrocarbon, and then delivers it to the engine 14. With reference now to 2 and further reference to 1 For example, the EVAP system 30 includes the fuel tank 18 and an evaporative emission control (EVAP) canister 34, which may be filled with activated carbon 36 or other suitable absorbent material. The activated carbon 36 absorbs and stores the hydrocarbon from the fuel vapor 32 that is carried over from the fuel tank 18 during events such as refueling. In the embodiment shown, the EVAP canister 34 includes a fresh air or ambient air port 38, a fuel vapor inlet 40, and a fuel vapor outlet 42. The fuel vapor inlet is in fluid communication through a fuel vapor line 44 that extends between the fuel tank 18 and the EVAP canister 34 with the fuel tank 18 of the vehicle.

In an exemplary embodiment, the fuel vapor vent 42 is in fluid communication with an intake system 16 of the internal combustion engine 14 through a fuel vapor supply line 48. A purge pump 50 may be operative during certain engine operating phases to draw fresh air 52 into and through the EVAP canister 34 via the fresh air port 38 to suck. This process draws stored hydrocarbon from the activated carbon 36 through the fuel vapor supply line 48 to the engine and burns it there. In this process, the EVAP canister 34 is regenerated and prepared to store additional hydrocarbons from the fuel vapor 32 that is subsequently removed from the vehicle's fuel tank 18 .

In an exemplary embodiment, the vehicle fuel tank 18 includes an interior area 56 in which liquid HC fuel 58 is stored. The fuel vapor 32 is typi specifically in the region 60 of the fuel tank 18 above the surface of the liquid HC fuel 58 through vaporization and/or agitation of the liquid HC fuel. A fuel pump assembly 62 is disposed within the fuel tank interior 56 and includes a fuel pump 63 configured to be in constant contact with the liquid HC fuel 58 . At the in 2 In the embodiment shown, the fuel pump assembly 62 is a drop-in pump that is installed in the fuel tank 18 through an opening 64 in an upper portion of the tank. The fuel pump assembly 62 further includes a mounting flange assembly 66 which seals the fuel tank opening 64 and thus supports the fuel pump 63 by sealing engagement therewith. Other fuel pump configurations, including those located external to the fuel tank 18, are contemplated within the scope of the present disclosure. The fuel pump 63 of the fuel pump assembly 62 is operative during normal operation of the engine 14 to deliver pressurized HC liquid fuel 58 into the intake system 16 of the engine 14 via the pressurized fuel line 20 previously described.

As indicated, when the vehicle is refueled, a significant amount of fuel vapor 32 may be generated in the fuel vapor region 60 of the vehicle's fuel tank 18 . As liquid fuel 58 is added to the fuel tank through fuel filler line 70, thereby raising the level of liquid fuel 58 in the tank, the fuel vapor is subjected to the pressure of the rising liquid fuel and is therefore forced to exit the fuel vapor region 60 of the tank through fuel vapor line 44. The fuel vapor traverses the conduit and enters the EVAP canister where the hydrocarbon in the vapor is stored in activated charcoal 36 . Excess vapor pressure is released through fresh air inlet 38 . As indicated herein, the movement of the liquid fuel 58 in the fuel tank 18 due to the flow of incoming fuel via the fuel filler line may result in more than normal HC liquid fuel being suspended in the fuel vapor 32 . It is desirable to remove as much of the suspended HC fuel in the fuel vapor as possible before the fuel vapor is directed to the EVAP canister 34 via the fuel vapor line 44 .

With reference to 2 , 3 and 4 is in one embodiment a vapor-liquid separator, such as. B. a vapor-liquid cyclone separator 76, disposed integrally with the fuel pump assembly 62 and can remove HC liquid fuel 58 that is suspended in the fuel vapor 32, and return it to the HC liquid fuel reservoir of the fuel tank 18. The vapor-liquid cyclone separator 76 includes a separator housing 78 having a vapor inlet 80, a vapor outlet 82, and a liquid fuel outlet 84. In one embodiment, the separator housing 78 includes a cylindrical upper portion 86 and a conical lower portion 88. The cylindrical upper portion 86 includes the Steam inlet 80 designed to intersect with or open into the upper part in a tangential orientation, as in FIG 4 illustrated. In one embodiment, the vapor inlet may be fluidly connected to a fill shut-off riser 90 extending outwardly therefrom and toward the HC liquid fuel reservoir 58 in the fuel tank 18 . Fuel vapor 32 enters vapor-liquid cyclone separator 76 through riser 90, as further described herein. The vapor outlet 82 of the vapor-liquid cyclone separator 76 is in fluid communication with the fuel vapor line 44 extending from the fuel vapor inlet 40 of the EVAP canister 34, and the liquid fuel outlet 84 is in communication with the fuel vapor region 60 of the fuel tank 18.

As described herein, in the operation of the EVAP system 30 it is desirable to remove as much liquid hydrocarbon as possible from the fuel vapor 32 before it is introduced into the EVAP canister 34 . In one example, during refueling, the movement of the liquid HC fuel 58 and the rising fuel level in the fuel tank 18 causes excess HC fuel 58 to become suspended in the fuel vapor 32 . The increasing pressure in the fuel tank resulting from the rising fuel level in the fuel tank moves the fuel vapor into and through the riser tube 90 where it exits tangentially into the cylindrical upper portion 86 of the separator housing 78 of the vapor-liquid cyclone separator 76. As in 4 As illustrated, the tangential entry of the fuel vapor 32 into the cylindrical upper portion 86 of the separator housing 78 causes the fuel vapor to swirl, resulting in the separation of the liquid HC fuel 58 from the vapor 32 . The HC liquid fuel collects on the wall of the separator housing 78 and drains through the conical lower portion 88 and back through the liquid fuel outlet 84 to the liquid fuel reservoir in the fuel tank. The fuel vapor 32 (now stripped of excess HC liquid fuel) exits the vapor-liquid cyclone separator 76 through the vapor outlet 82 and is transported through the fuel vapor line 44 to the EVAP canister 34 .

In one embodiment, the fill shut-off riser 90 shuts off the flow of fuel into the fuel tank 18 when the HC liquid fuel 58 fills a reached full level. When the level of liquid fuel reaches the fill shut-off riser inlet 92, it blocks the escape of fuel vapor 32 from the fuel tank 18 and causes the pressure in the tank to rise. The increase in pressure acts on the gas station nozzle (not shown) in a known manner to signal that the fuel tank is full; this leads to a termination of the supply of fuel to the fuel tank 18.

In one embodiment, the separator housing vapor outlet 82 may include a tubular extension 94 having a valve seat 96 disposed therein. A ball valve 98 is trapped in the tubular extension between the valve seat 96 and the end 100 thereof. The ball valve 98 and valve seat 96 cooperate to prevent fuel from entering the fuel vapor line 44 and the EVAP canister 34 in the event of a vehicle rollover. Should the fuel tank 18 be inverted in a vehicle rollover, the ball valve 98 will seat against the valve seat 96 to prevent the flow of HC liquid fuel through the tubular extension.

With reference now to 5 For example, in one embodiment, it may be necessary to mount the cyclonic vapor-liquid separator 76 in the fuel tank 18 remote from the fuel pump assembly 62 . In such a case, the vapor-liquid cyclone separator may be mounted to an upper surface (ie, top) 106 inside the fuel tank. An in-tank fuel vapor line 108 extends from the vapor outlet 82 of the separator housing 78 and is fluidly connected to the fuel vapor line 44 that extends between the fuel tank and the EVAP canister 34 . In one embodiment, the fluidic connection between the in-tank fuel vapor line 108 and the fuel vapor line 44 is at the mounting flange assembly 66 of the fuel pump assembly 62 to minimize the required openings in the fuel tank. With this configuration, the operation of the EVAP system 30 remains substantially the same as described herein.

While the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents substituted without departing from the scope. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope of the disclosure. Therefore, the present disclosure should not be limited to the particular forms, but should include all forms that fall within its scope.

Claims (10)

An evaporative emission control (EVAP) system that collects HC-laden fuel vapor (fuel vapor) from a fuel tank, comprising: a fuel tank, an evaporative emission canister (EVAP canister), a fuel vapor line extending between the fuel tank and the EVAP canister, and an in-tank fuel pump assembly, comprising: a fuel pump and a vapor-liquid separator that is integral with the fuel pump assembly and removes HC liquid fuel suspended in the fuel vapor and returns it to a HC liquid fuel reservoir of the fuel tank and is in fluid communication with the fuel vapor line to transport the fuel vapor to the EVAP - to promote containers. EVAP system after claim 1 wherein the vapor-liquid separator comprises a vapor-liquid cyclone separator. EVAP system after claim 2 , wherein the vapor-liquid cyclone separator comprises a separator body having a cylindrical upper portion with a vapor inlet and a vapor outlet and a conical lower portion with a liquid fuel outlet, the vapor inlet opening into the cylindrical upper portion in a tangential orientation to form a to cause swirling of the fuel vapor and to separate HC liquid fuel therefrom. EVAP system after claim 3 , whereby the HC liquid fuel collects on the walls of the cylindrical upper part and is returned to the HC liquid fuel reservoir of the fuel tank through the liquid fuel outlet of the conical lower part. EVAP system after claim 3 wherein the vapor-liquid cyclone separator further comprises a fuel shut-off riser fluidly connected to the vapor inlet and defining a conduit for entry of fuel vapor into the vapor-liquid cyclone separator. EVAP system after claim 1 wherein the fuel pump assembly is a drop-in pump installed in the fuel tank through an opening in the fuel tank. EVAP system after claim 6 wherein the fuel pump assembly further comprises a mounting flange assembly sealingly closing the opening in the fuel tank and supporting the vapor-liquid cyclone separator and the fuel pump therein. EVAP system after claim 3 wherein the vapor outlet comprises a tubular extension having a valve seat disposed therein and a ball valve trapped within the tubular extension between the valve seat and an end thereof to prevent fuel from entering the fuel vapor line and the EVAP canister. Motor vehicle, comprising: an internal combustion engine receiving pressurized fuel from a fuel tank via a pressurized fuel line, and an evaporative emission control (EVAP) system that collects fuel vapor from the fuel tank, comprising: a fuel tank, an evaporative emission canister (EVAP canister), a fuel vapor line extending between the fuel tank and the EVAP canister, and an in-tank fuel pump assembly, comprising: a fuel pump and a vapor-liquid separator that is integral with the fuel pump assembly and removes HC liquid fuel suspended in the fuel vapor and returns it to a HC liquid fuel reservoir of the fuel tank and is in fluid communication with the fuel vapor line to transport the fuel vapor to the EVAP - to promote containers. motor vehicle after claim 9 wherein the vapor-liquid separator comprises a vapor-liquid cyclone separator including a separator housing having a cylindrical upper portion with a vapor inlet and a vapor outlet and a conical lower portion with a liquid fuel outlet, the vapor inlet opening into the cylindrical upper portion in a tangential orientation to cause swirling of the fuel vapor resulting in separation of the HC liquid fuel therefrom.

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