US20110303197A1

US20110303197A1 - Microcondenser device

Info

Publication number: US20110303197A1
Application number: US12/797,257
Authority: US
Inventors: Dennis B. Chung
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2010-06-09
Filing date: 2010-06-09
Publication date: 2011-12-15
Also published as: EP2580461A4; EP3219532B1; JP2016121691A; EP3219532A1; WO2011156452A1; JP6142019B2; JP2013531759A; CN103069146A; JP5878921B2; EP2580461A1; US9334837B2; US20130118457A1; CN103069146B; MX2012014424A; EP2580461B1; CA2801604C; CA2801604A1

Abstract

A microcondenser device for an evaporative emission control system associated with an internal combustion engine includes a housing having a lower wall and at least one side wall extending upward from the lower wall. The lower wall and the at least one side wall together defining a chamber in the housing. A thermoelectric element is supported by the at least one side wall in spaced relation relative to the lower wall. An inlet is defined in the housing for admitting fuel vapor into the chamber. A condensation outlet is defined in the housing for discharging liquid fuel that is condensed from the fuel vapor in the chamber. A porous heat sink element is received in the chamber for absorbing the fuel vapor admitted through the inlet. The porous heat sink element is in conductive thermal contact with the thermoelectric element.

Description

BACKGROUND

The present disclosure generally relates to evaporative emission control systems for internal combustion engines, and more particularly relates to a microcondenser device for an evaporative emission control system associated with an internal combustion engine.
Conventional vehicle fuel systems associated with internal combustion engines typically employ a fuel canister for receiving fuel vapor from a vehicle's fuel tank. The fuel canister is adapted to temporarily retain the received vapor therein to prevent it from being released to the atmosphere. More particularly, fuel vapor can enter the fuel canister from the fuel tank wherein the fuel vapor is absorbed and retained in a carbon bed of the fuel canister. Typically, the retention of the displaced fuel vapor within the fuel canister is only temporary as the fuel vapor retained in the fuel canister is periodically purged to allow the canister to accommodate and absorb additional fuel vapor from the fuel tank. During such purging, the fuel vapor captured by the canister can be sent to the vehicle's engine, and particularly to an induction system of the engine, for combustion.
Various other systems have been proposed to more strictly control containment of fuel vapors and/or improve vehicle efficiency by controlling fuel vapor processing. For example, some systems include a bladder disposed in the vehicle's fuel tank that expands and contracts to control fuel vapor. A pump can be used in association with the bladder for applying pressure to the walls of the bladder. The pressure is applied for purposes of forcing the bladder walls against the fuel contained therein to prevent or limit vapor formation. A fuel canister, as described in the preceding paragraph, can optionally be used in the bladder fuel system for capturing fuel vapor that forms despite the use of the bladder.
Also known is a canisterless evaporative emission control system for an internal combustion engine. One particular known system includes a fuel tank wherein vaporized fuel is generated and a microcondenser device for processing the vaporized fuel received from the fuel tank. The microcondenser device has a heat sink portion formed of carbon foam in thermal communication with a thermoelectric element for removing heat from the heat sink portion. The fuel vapor is processed by passing the fuel vapor through the heat sink portion to remove heat therefrom and condense at least a portion of the fuel vapor to liquid fuel. Drawbacks of this known canisterless control system include significant power consumption requirements for the thermoelectric element and a significant volume of uncondensed fuel vapor passing through the microcondenser device.

SUMMARY

According to one aspect, a microcondenser device is provided for an evaporative emission control system associated with an internal combustion engine. The device includes a housing having a lower wall and at least one side wall extending upward from the lower wall. The lower wall and the at least one side wall together define a chamber in the housing. A thermoelectric element is supported by the at least one side wall in spaced relation relative to the lower wall. An inlet is defined in the housing for admitting fuel vapor into the chamber. A condensation outlet is defined in the housing for discharging liquid fuel that is condensed from the fuel vapor in the chamber. A porous heat sink element is received in the chamber for absorbing the fuel vapor admitted through the inlet. The porous heat sink element is in conductive thermal contact with the thermoelectric element.
According to another aspect, a microcondenser device for an evaporative emission control system includes a housing having an inlet for receiving fuel vapor and a condensation outlet for discharging condensed fuel vapor. A porous heat sink element is disposed in the housing and fluidly interposed between the inlet and the condensation outlet for absorbing the fuel vapor received through the inlet. A thermoelectric element is in thermal contact with the thermal heat sink element for removing heat from the fuel vapor absorbed by the porous heat sink element to condense the fuel vapor. At least one support baffle supports the porous heat sink element within the housing.
According to a further aspect, a microcondenser device for an evaporative emission control system includes a housing having an inlet for receiving fuel vapor and a condensation outlet for discharging condensed fuel vapor. A porous heat sink element is disposed in the housing and is fluidly interposed between the inlet and the condensation outlet for absorbing the fuel vapor received through the inlet. A thermoelectric element is in thermal contact with the porous heat sink element for removing heat from the fuel vapor absorbed by the porous heat sink element to condense the fuel vapor. A heat removal assembly is in conductive thermal contact with a hot side of the microcondenser element for removing heat therefrom. The heat removal assembly comprises at least one of: a heat pipe or a liquid cooling circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an evaporative emission control system having a microcondenser device for processing fuel vapor.

FIG. 2 is a perspective view, partially in cross-section, of the microcondenser device.

FIG. 3 is an elevational cross-section view of the microcondenser device.

FIG. 4 is plan cross-section view of the microcondenser device.

FIG. 5 is an elevational cross-section view of a microcondenser device according to an alternate embodiment.

FIG. 6 is a plan cross-section view of the microcondenser device of FIG. 5.

FIG. 7 is an elevational cross-section view of a microcondenser device according to another alternate embodiment.

FIG. 8 is a plan cross-section view of the microcondenser device of FIG. 7.

FIG. 9 is an elevational cross-section view of a microcondenser device according to yet another alternate embodiment.

FIG. 10 is a plan cross-section view of the microcondenser device of FIG. 9.

FIG. 11 is a schematic elevational view of a microcondenser device having a heat pipe (shown in cross-section) for removing heat therefrom.

FIG. 12 is a schematic elevational view of a microcondenser device having a cooling fluid circuit for removing heat therefrom.

DETAILED DESCRIPTION

Referring now to the drawings wherein the showings are for purposes of illustrating one or more exemplary embodiments and not for purposes of limiting same, FIG. 1 schematically shows an evaporative emission control system 10 for an internal combustion engine 12. As shown, the engine 12 is provided with an induction system including an intake pipe 14 in which a throttle valve 16 is operatively mounted. A throttle valve opening (THA) sensor 18 is connected to the throttle valve 16. The throttle valve opening sensor 18 outputs a signal corresponding to the opening angle (THA) of the throttle valve 16 and supplies the signal to an electronic control unit (ECU) 20. Fuel injection valve 22, only one of which is shown, are inserted into the intake pipe 14 at locations intermediate between the cylinder block of the engine 12 and the throttle valve 16 and slightly upstream of the respective intake valves (not shown). The fuel injection valves 22 can be connected through a fuel supply pipe 24 to a fuel tank 26 and a fuel pump unit 28 is provided therealong for delivering fuel from the tank 26 to the fuel injection valves 22. Each fuel injection valve 22 can be electrically connected to the ECU 20, and its valve opening can be controlled by a signal from the ECU 20.
One or more sensors can be provided on the intake pipe 14 for monitoring conditions at the intake pipe. For example, the intake pipe 14 can be provided with an intake pipe absolute pressure (PBA) sensor 34 for detecting an absolute pressure (PBA) in the intake pipe 14 and an intake air temperature (TA) sensor 36 for detecting an air temperature (TA) in the intake pipe 14 at positions downstream of the throttle valve 16. These sensors, including sensors 34, 36, can each output a signal corresponding to a sensed condition (e.g., PBA or TA) and supply the outputted signal to the ECU 20. In addition, the fuel tank 26 can be provided with one or more sensors for monitoring specific conditions associated therewith, including, for example, a tank pressure (PTANK) sensor 38 for detecting a pressure (PTANK) in the fuel tank, a fuel temperature (TGAS) sensor 40 for detecting a fuel temperature (TGAS) in the fuel tank 26, and a fuel level sensor 42 for detecting a fuel level (i.e., a remaining fuel amount) in the fuel tank 26. Like the other sensors described herein, the fuel tank sensors, including sensors 38, 40, 42, can each output a signal corresponding to a sensed condition at the fuel tank 26 and provide the signal to the ECU 20.
Additional sensors can be provided on or in association with the engine 12. More particularly, an engine rotational (NE) sensor 44 for detecting an engine rotational speed (NE) can be disposed near the outer periphery of a camshaft or crankshaft (both not shown) of the engine 12. There can also be provided an engine coolant temperature sensor 46 for detecting a coolant temperature (TW) of the engine 12 and an oxygen concentration sensor (also referred to as a “LAF sensor”) 48 for detecting an oxygen concentration in exhaust gases from the engine 12. Detection signals from these sensors 44, 46, 48 can be supplied to the ECU 20. The LAF sensor 48 can function as a wide-area air-fuel ratio sensor adapted to output a signal substantially proportional to an oxygen concentration and exhaust gases (i.e., proportional to an air-fuel ratio of air-fuel mixture supplied to the engine 12).
The evaporative emission control system 10 further includes a microcondenser device 50. With additional reference to FIG. 2, the microcondenser device 50 includes a housing 52 having an inlet 54 for receiving fuel vapor and a condensation outlet 56 for discharging condensed fuel vapor. In the illustrated embodiment, the inlet 54 is connected to the fuel tank 26 through vapor line 58 so that fuel vapors formed in the fuel tank 26 can be delivered to the microcondenser device 50. The condensation outlet 56 is also connected to the fuel tank 26. In particular, the condensation outlet 56 is connected to the fuel tank 26 through condensation discharge line 60 for directing condensed vapor (i.e., liquid fuel) from the microcondenser device back to the fuel tank 26. The housing 52 can also have a vapor outlet 62 for discharging fuel vapor that remains vaporized after passing through the microcondenser device 50. In the illustrated embodiment, the vapor outlet 62 is fluidly connected to the intake pipe 14 upstream of the fuel injectors 22 via vapor line 64. This allows fuel vapor discharged by the microcondenser device 50 to be recirculated through the internal combustion engine 12 for combustion therein.
As will be described in more detail below, the microcondenser device 50 can also include a thermoelectric element 66 for condensing fuel vapors admitted through the inlet 54. The thermoelectric element 66 can be a Peltier microelement that employs or uses the Peltier effect to condense evaporative or vaporized fuel received from the fuel tank 26 via the vapor line 58. Advantageously, providing the thermoelectric element 66 as a Peltier microelement can be effective for condensing vaporized fuel from the fuel tank 26 while being of a small size and requiring minimum power consumption thereby not taxing the spatial layout of the vehicle or its electrical system. Operation of the microcondenser device 50 can occur as described in U.S. Pat. No. 7,527,045, which is expressly incorporated in its entirety herein.
With additional reference to FIGS. 3 and 4, the housing 52 has a bottom or lower wall 70 and at least one side wall 72, 74, 76, 78 extending upward from the lower wall 70. The lower wall 70 and the at least one side wall 72-78 together define a chamber 80 in the housing 52. In the embodiment illustrated in FIGS. 2-4, the housing 52 has a cuboid or box-shaped configuration such that the at least one side wall includes four rectangular side walls 72, 74, 76, 78, each extending orthogonally upward from the lower wall 70. As shown, the inlet 54 is defined in the housing 52, and particularly the side wall 76 thereof, for admitting fuel vapor into the chamber 80. The condensation outlet 56 is defined in the housing 52, and particularly in the side wall 72 thereof, for discharging liquid fuel that is condensed from the fuel vapor in the chamber 80. The vapor outlet 62 is defined in the housing 52, and particularly in the side wall 78 thereof, for discharging uncondensed fuel vapor from the chamber 80.
The thermoelectric element 66 is supported by the at least one side wall (i.e., side walls 72-78 in the embodiment illustrated in FIGS. 2-4) in spaced relation relative to the lower wall 70. By this arrangement, the thermoelectric element 66 is spaced apart vertically from the bottom wall 70. For supporting the thermoelectric element 66 in spaced relation relative to the lower wall 70, the at least one side wall (i.e., side walls 72-78) can include a recess 82 defined by a shoulder 84 and face 86 extending upward from the shoulder 84. In particular, each of the side walls 72-78 of the illustrated embodiment can include shoulder 84 and face 86 defining the recess 82. As shown, the thermoelectric element 66 can be supported on the shoulder 84 and sized such that at least one peripheral edge of the thermoelectric element 66 is positioned closely adjacent the face 86. In the illustrated embodiment, the thermoelectric element 66 can have a rectangular configuration including four peripheral edges 66 a and each peripheral edge 66 a can be positioned closely adjacent face 86 of a corresponding one of the side walls 72-78. By this arrangement, the thermoelectric element 66 is nestably received within the recess 82 defined in the housing 52.
A porous heat sink element 100 can be disposed in the housing 52, and particularly received in the chamber 80 of the housing 52. The porous heat sink element is fluidly interposed between the inlet 54 and the condensation outlet 56 for absorbing the fuel vapor received or admitted through the inlet 54. The thermoelectric element 66 can be in thermal contact with the porous heat sink element 100 for removing heat from the fuel vapor absorbed by the porous heat sink element 100 to condense the fuel vapor. In particular, the porous heat sink element 100 can be in conductive thermal contact with the thermoelectric element 66. In addition to be interposed between the inlet 54 and the condensation outlet 56, the porous heat sink element 100 is also fluidly interposed between the inlet 54 and the vapor outlet 62, which discharges fuel vapor that remains vaporized after passing through the porous heat sink 100.
In one embodiment, the porous heat sink element 100 is a carbon foam heat sink element. Being formed of carbon foam provides advantages such as higher thermal conductivity and greater surface area per unit volume than conventional heat sinks and/or heat sinks formed of aluminum fins. Moreover, the carbon foam heat sink element 100 has greater heat transfer efficiency than conventional arrangements which results in the overall electric load needed to power the microcondenser device 50 being considerably lower than would be necessary if the heat sink were formed with conventional fins.
In the illustrated embodiment, a copper plate 102 is interposed between the porous heat sink element 100 and the thermoelectric element 66. Accordingly, conductive heat transfer occurs from the porous heat sink element 100, then to the copper plate 102, and next to the thermoelectric element 66. Using the copper plate 102 allows for improved heat transfer from the porous heat sink element 100 to the thermoelectric element 66. In particular, the copper plate 102 can have an improved flatness, particularly on a side 104 that interfaces with the porous heat sink element 100 (i.e., improved flatness compared to other efficient heat transfer materials). In addition, a thermal paste 106 can be interposed between at least one of the copper plate 102 and the thermoelectric element 66 or the copper plate 102 and the porous heat sink element 100. In the illustrated embodiment, as shown, thermal paste 106 is interposed between both the copper plates 102 and the thermoelectric element 66 and the copper plate 102 and the porous heat sink element 100. The thermal paste 106 facilitates better heat transfer between conductive elements of the microcondenser device 50.
As shown in the illustrated embodiment, the copper plate 102 is supported by the shoulder 84 and the thermoelectric element 66 is supported on top of the copper plate 102. Together, the thermoelectric element 66 and the copper plate 102 are nestably received within the recess 82 defined in the housing 52. Particularly, in the illustrated embodiment, these elements 66, 102 form an upper side of the housing 52 and close the chamber 80 defined by the housing 52. A seal 108 can be interposed between the underside 104 of the copper plate 102 and the shoulder 84 defined in each of the side walls 72-78. The nesting relation of the copper plate 102 and the thermoelectric element 66 within the recess 82 and/or the provision of the seal 108 is believed to advantageously reduce or eliminate frost or fog formation on the microcondenser device 50, and particularly the housing 52 thereof, which improves efficiency of the device 50 (i.e., less power is needed to operate the device). [Question for inventors: what material is the seal 108 formed of?]
Also to improve efficiency of the microcondenser device 50, the housing 52 can be formed of a plastic material. This provides the housing 52 with a low heat mass body and a low thermal conductivity body material. The particular plastic material employed for the housing 52 can have sufficient rigidity while otherwise reducing the amount of energy needed for the thermoelectric element 66 to cool vaporized fuel passing through the porous heat sink element 100. Using plastic also provides an additional minimal weight benefit through the use of a lighter material.
Specifically, for example, the body material of the housing 52 can be polyamide, polyacetal, PEI, PPS, or any other fuel-resistant plastic material providing for low heat loss and/or low thermal mass. In addition, to further limit thermal loss to the environment, an insulation or an insulating layer can be disposed one of: around an exterior of the housing 52 or inside the housing around the porous heat sink element 100. In the illustrated embodiment, a foam insulating layer 110 is shown provided around an exterior of the housing 52. Alternatively, other insulating materials can be applied to the exterior of the housing 52. For example, aerogels or other foams can be applied to an exterior of the housing for insulating the housing from thermal losses to the surrounding environment.
The microcondenser device 50 can additionally include at least one support baffle supporting the porous heat sink element 100 within the housing 52. As will be described in more detail below, the at least one support baffle supports the porous heat sink element 100 in an elevated position (i.e., in spaced apart relation) from the lower wall 70 and in conductive thermal contact with the thermoelectric element 66. As will also be described in more detail below, the at least one support baffle can urge the porous heat sink element 100 toward the thermoelectric element 66 and/or into thermal contact with the thermoelectric element 66. The at least one support baffle can be one or more baffles shaped or configured to provide various sub-chambers within the chamber 80 of the housing 52. The baffles can be formed of a foam insulation material, such as a Teflon foam insulation, for example, which provides the baffles with some resiliency and enable the stacked baffles to urge the porous heat sink element 100 toward the copper plate 102, which assists in efficient heat transfer therebetween.
In the illustrated embodiment, the at least one support baffle includes a plurality of stacked baffles, which facilitates the baffles urging or supplying support pressure against the porous heat sink element 100. Whether stacked, shaped or otherwise configured, the one or more support baffles can be arranged to efficiently direct fuel vapor into the porous heat sink element 100 and/or to facilitate efficient liquid drainage (i.e., condensed fuel vapor). In the illustrated embodiment, the plurality of baffles includes a base baffle 112 having a cut out or recess 114 accommodating the condensation outlet 56. Intermediate baffles 116, 118, 120, 122 are stacked on the base baffle 112. In particular, intermediate baffles 116, 118 are together stacked and form a first pair of stacked baffles. Likewise, intermediate baffles 120, 122 are together stacked and form a second pair of stacked baffles. Thus, the baffles 116-122 are arranged in stacked pairs wherein the first pair of stacked baffles 116, 118 are together stacked adjacent the inlet 54 and the second pair of baffles 120, 122 are stacked adjacent the vapor outlet 62, and wherein the pairs of stacked baffles 116, 118 and 120, 122 flank the condensation outlet 56.
The baffles can be arranged so as to direct gas and/or liquid flow within the microcondenser device 50 and support the porous heat sink element 100. For example, upper baffles 124, 126 are disposed in stacked relation above the intermediate baffles 116-122 and can directly support the porous heat sink element 100. In particular, the illustrated embodiment, the upper baffle 124 is stacked on the first pair of intermediate baffles 116, 118 adjacent the vapor inlet 54 and the upper baffle 126 is stacked on the second pair of intermediate baffles 120, 122 adjacent the vapor outlet 62. Like the intermediate baffles 116-122, the upper baffles 124, 126 can be laterally spaced apart from one another to flank the condensation outlet 56.
In the illustrated embodiment of FIGS. 2-4, the baffles are arranged so as to define a plenum chamber 128 adjacent the vapor inlet 54 and extending from the side wall 72 to the side wall 74. The plenum chamber 128 can allow the fuel vapor admitted through the vapor inlet 54 to expand along a dimension of the porous heat sink element 100 extending from the side wall 72 to the side wall 74 and thus more effectively absorb the fuel vapor. In particular, the plenum chamber 128 of the illustrated embodiment is formed by the side walls 72, 74, 76, the baffles 118 and 124, and the porous heat sink element 100. The plenum chamber 128 extends along substantially an entire width of the porous heat sink element 100 (e.g., the width extending between the side walls 72, 74). The plenum chamber 128 can function to ensure that fuel vapor entering through the inlet 54 is allowed to spread out before being absorbed into the porous heat sink element 100.
The baffles also define a condensation chamber 130 vertically between the condensation outlet 56 and the porous heat sink element 100. As shown, the condensation chamber 130 is disposed below the porous heat sink element 100. This allows gravity to assist in removing condensed fuel from the porous heat sink element 100 and directing the same to the condensation outlet 56. The upper baffle 124 is smaller in the illustrated embodiment that the upper baffle 126, which defines an expanded area 132 of the condensation chamber 130. The expanded area 132 facilitates gravitational removal of condensed fuel from the porous heat sink element 100 on a side of the condensation chamber 130 adjacent the vapor inlet 54. [is this correct?]
With reference to FIGS. 5 and 6, a microcondenser device 150 is illustrated. The microcondenser device 150 can be the same as the microcondenser device 50 except as indicated below. In FIGS. 5 and 6, the base and intermediate stacked baffles of the microcondenser device 50 are replaced with a single shaped baffle 152 that includes a base portion 154 similar in configuration to the base baffle 112 and intermediate baffle portions 156, 158 that are similar in configuration to the stacked intermediate baffles 116-122. The microcondenser device 150 includes upper baffles 160, 162 disposed in stacked relation on the intermediate baffle portions 156, 158. Unlike the microcondenser device 50, the microcondenser 150 has its upper baffles 160, 162 sized and arranged to provide varying shapes for plenum chamber 164 and condensation chamber 166. In particular, the upper baffle 160 has a rear side 168 aligned with a rear side 170 of the intermediate baffle portion 156. Accordingly, no expanded area 132 is defined above the intermediate baffle portion 156; however, the plenum chamber 164 has an increased depth (i.e., a dimension from the vapor inlet 54 and/or side wall 76 to the upper baffle 160). Instead of the expanded area 132, an expanded area 172 is disposed above the intermediate baffle portion 158. The expanded area 172 results from the rear edge 174 of the upper baffle 162 being laterally spaced apart from the rear side 176 of the intermediate baffle portion 158.
With reference to FIGS. 7 and 8, another microcondenser device 250 is illustrated. The microcondenser device 250 can be the same as the microcondenser device 150 except as indicated below. In the embodiment illustrated in FIGS. 7 and 8, the upper baffle 162 is replaced with upper baffle 126 (i.e. the same baffle used in the microcondenser device 50). Accordingly, in this embodiment, there is no expanded area of the condensation chamber 130 above the intermediate baffle portion 156 or above the intermediate baffle portion 158, only the enlarged plenum chamber 164.
With reference to FIGS. 9 and 10, still another microcondenser device 350 is illustrated, which can be the same as the microcondenser device 150 except as indicated below. In the microcondenser device 350, upper baffle 124 (same as used in the microcondenser 50) is disposed above the intermediate baffle portion 156 and the upper baffle portion 162 is disposed above the intermediate baffle portion 158. Accordingly, by this arrangement, expanded area 132 is disposed above the intermediate baffle portion 156 and expanded area 172 is disposed above the intermediate baffle portion 158. A small plenum chamber 128 is also disposed above the intermediate baffle portion 156 adjacent the inlet 54.
Returning reference to FIGS. 2-4, the porous heat sink element 100 can have a varying porosity. One exemplary varying porosity for the porous heat sink element 100 is schematically illustrated by the stippling in the figures. As shown, the porous heat sink element 100 can have an increased porosity at a first side or portion 100 a, which is adjacent the plenum chamber 128 and the inlet 54, than adjacent a second side or portion 100 b. The porous heat sink element 100 can also have an increased porosity adjacent an underside or underside portion 100 c than an upper side or upper side portion 100 d that is adjacent the thermoelectric element 66. While the illustrated embodiment includes progressively decreasing porosity from the first side portion 100 a to the second side portion 100 b and from the underside portion 100 c to the upper side portion 100 d, it is to be appreciated that such varying porosity could occur only from one side to another (e.g., from side portion 100 a to side portion 100 b or from side portion 100 c to side portion 100 d). Alternatively, other arrangements or patterns of varying porosity could be used with the heat sink element 100.
As best shown in FIG. 3, the arrangement of the vapor inlet 54 and the outlets 56, 62 relative to one another can facilitate efficient vapor flow and liquid flow through the microcondenser device 50. As used herein, relative positioning can refer to positioning of a central axis or central area of each of the inlet 54 and outlets 56, 62 relative to one another. In particular, as shown, the vapor outlet 62 can be relatively positioned vertically above the vapor inlet 54 and above the condensation outlet 56. The condensation outlet 56 can be relatively positioned below the vapor inlet 54 and below the vapor outlet 62. The vapor inlet 54 can be disposed vertically between the vapor outlet 62 and the condensation outlet 56. In addition to relative positioning, relative sizing can facilitate efficient fuel flow through the microcondenser device 50. For example, as shown, the vapor inlet 54 can have an increased size relative to the condensation outlet 56, which itself can have an increased size relative to the vapor outlet 62.
With reference to FIGS. 11 and 12, the microcondenser device 50 can additionally include a heat removal assembly 170 or 172 that is in thermal contact with a hot side 66 b of the thermoelectric element 66. The heat removal assembly 170 or 172 can comprise at least one of heat pipe 170 (FIG. 11) or a liquid cooling circuit 172 (FIG. 12). In FIG. 11, an exemplary heat pipe 170 is shown having a casing 174, a wick 176 and a vapor cavity 178. As is known and understood by those skilled in the art, the heat pipe 170 can facilitate more rapid removal of heat from the hot side 66 b of the thermoelectric element 66, which reduces the power consumption of the thermoelectric element for condensing fuel vapor in the cavity 80. In FIG. 12, an exemplary liquid cooling circuit 172 is shown having a pump 180, a heat exchanger 182 and a liquid circulation loop 184. As is known and understood by those skilled in the art, the pump 180 circulates a heat transfer fluid (e.g., antifreeze) in the loop 184 from the hot side 66 b of the thermoelectric element 66 where the fluid absorbs heat from the thermoelectric element 66 to the heat exchanger 182 where the fluid dissipates its absorbed heat. Alternatively or in addition, the hot side 66 a of the thermoelectric element 66 can be cooled by convection fins and/or a fan (both not shown). Although not shown, a thermal paste can be used between the heat removal assembly 170 or 172 and the hot side 66 a of the thermoelectric element 66. Using the heat pipe 170 or the liquid cooling circuit 172, rapid heat removal can occur from the hot side 66 a of the thermoelectric element 66 increasing its efficiency.
Advantageously, the microcondenser devices described herein can provide improved efficiencies which allow the devices to have smaller footprints when employed in a vehicle electrical system. It will be appreciated that various of the above-disclosed and other features and functions, or alternatives or varieties thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.

Claims

1. A microcondenser device for an evaporative emission control system associated with an internal combustion engine, comprising:

a housing having a lower wall and at least one side wall extending upward from the lower wall, the lower wall and the at least one side wall together define a chamber in the housing;

a thermoelectric element supported by the at least one side wall in spaced relation relative to the lower wall;

an inlet defined in the housing for admitting fuel vapor into the chamber;

a condensation outlet defined in the housing for discharging liquid fuel that is condensed from the fuel vapor in the chamber; and

a porous heat sink element received in the chamber for absorbing the fuel vapor admitted through the inlet, the porous heat sink element in conductive thermal contact with the thermoelectric element.

2. The microcondenser device of claim 1 further including at least one support baffle supporting the porous heat sink element in an elevated position from the lower wall and in conductive thermal contact with the thermoelectric element.

3. The microcondenser device of claim 1 wherein the porous heat sink element is a carbon foam element having a varying porosity.

4. The microcondenser device of claim 1 further including a vapor outlet defined in the housing for discharging uncondensed fuel vapor, the vapor outlet elevated relative to the inlet and the inlet elevated relative to the condensation outlet.

5. The microcondenser device of claim 1 further including a heat pipe or a liquid cooling circuit for removing heat from the thermoelectric element.

6. A microcondenser device for an evaporative emission control system, comprising:

a housing having an inlet for receiving fuel vapor and a condensation outlet for discharging condensed fuel vapor;

a porous heat sink element disposed in the housing and fluidly interposed between the inlet and the condensation outlet for absorbing the fuel vapor received through the inlet;

a thermoelectric element in thermal contact with the porous heat sink element for removing heat from the fuel vapor absorbed by the porous heat sink element to condense the fuel vapor; and

at least one support baffle supporting the porous heat sink element within the housing.

7. The microcondenser device of claim 6 wherein the porous heat sink element is a carbon foam heat sink element.

8. The microcondenser device of claim 6 wherein the housing has a vapor outlet for discharging fuel vapor that remains vaporized after passing through the porous heat sink element, the porous heat sink element fluidly interposed between the inlet and the vapor outlet.

9. The microcondenser device of claim 8 wherein the housing includes a bottom wall and at least one side wall extending upward from the bottom wall, the thermoelectric element is spaced apart vertically from the bottom wall, the at least one support baffle supports the porous heat sink element in spaced apart relation from the bottom wall.

10. The microcondenser device of claim 9 wherein the at least one support baffle urges the porous heat sink element toward the thermoelectric element.

11. The microcondenser device of claim 9 wherein the at least one support baffle urges the porous heat sink element into thermal contact with the thermoelectric element.

12. The microcondenser device of claim 9 wherein a plenum chamber is formed by the at least one side wall, the at least one support baffle and the porous heat sink element, the plenum chamber extending along substantially an entire width of the porous heat sink element.

13. The microcondenser device of claim 12 wherein the porous heat sink element has an increased porosity adjacent the plenum chamber.

14. The microcondenser device of claim 9 wherein the porous heat sink element has an increased porosity adjacent a first side of the porous heat sink element disposed adjacent the inlet than a second side adjacent the vapor outlet.

15. The microcondenser device of claim 14 wherein the porous heat sink element has an increased porosity adjacent an underside of the porous heat sink element disposed adjacent the condensation outlet than an upper side adjacent the thermoelectric element.

16. The microcondenser device of claim 9 wherein the porous heat sink element has an increased porosity adjacent an underside of the porous heat sink element disposed adjacent the condensation outlet than an upper side adjacent the thermoelectric element.

17. The microcondenser device of claim 6 wherein the thermoelectric element is nestably received within a recess defined in the housing.

18. The microcondenser device of claim 17 wherein the housing includes a bottom wall and at least one side wall extending upward from the bottom wall, the at least one side wall includes a recess defined by a shoulder and face extending upward from the shoulder, the thermoelectric element supported on the shoulder and sized such that at least one peripheral edge of the thermoelectric element is positioned closely adjacent the face.

19. The microcondenser device of claim 18 wherein a copper plate is interposed between the porous heat sink element and the thermoelectric element.

20. The microcondenser device of claim 1 wherein a copper plate is interposed between the porous heat sink element and the thermoelectric element.

21. The microcondenser device of claim 20 wherein a thermal paste is interposed between at least one of: the copper plate and the thermoelectric element or the copper plate and the porous heat sink element.

22. The microcondenser device of claim 6 wherein the porous heat sink element has an increased porosity adjacent the inlet than adjacent the condensation outlet.

23. The microcondenser device of claim 6 wherein the housing is formed of a plastic material.

24. The microcondenser device of claim 6 wherein an insulating layer is disposed one of: around an exterior of the housing or inside the housing around the porous heat sink element.

25. The microcondenser of claim 6 further including a heat removal assembly for removing heat from a hot side of the microcondenser element, the heat removal assembly comprising at least one of: a heat pipe or a liquid cooling circuit.

26. A microcondenser device for an evaporative emission control system, comprising:

a heat removal assembly in conductive thermal contact with a hot side of the microcondenser element for removing heat therefrom, the heat removal assembly comprising at least one of: a heat pipe or a liquid cooling circuit.