Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
  • B60K15/03—Fuel tanks
  • B60K15/035—Fuel tanks characterised by venting means
  • B60K15/03504—Fuel tanks characterised by venting means adapted to avoid loss of fuel or fuel vapour, e.g. with vapour recovery systems
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
  • F02M25/08—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding fuel vapours drawn from engine fuel reservoir
  • F02M25/0854—Details of the absorption canister

Definitions

• the invention relates to a ventilation device for a fuel tank of an internal combustion engine according to the type of the main claim.
• a ventilation device with an adsorption filter for example an activated carbon filter
• US Pat. No. 4,175,526, US Pat. No. 4,862,856 which prevents fuel vapors from escaping into the atmosphere from a fuel tank.
• the fuel vapors arise as soon as the fuel exceeds the saturation temperature, which is dependent on the ambient pressure. First, those parts of the fuel that have the lowest saturation temperature evaporate.
• the evaporation rate of the fuel increases with increasing fuel temperature or falling ambient pressure.
• the fuel vapors are a heavy burden on the environment and a health hazard for people, especially when inhaled.
• the adsorption filter is connected to the fuel tank by a filter line that ends in the interior of the adsorption filter, for example in the area that is filled with activated carbon.
• a suction line which is controlled by a tank ventilation valve, connects the adsorption filter with a downstream of a throttle selorganes lying section of an intake manifold of the internal combustion engine.
• the fuel vapors are drawn in by the negative pressure prevailing in the intake manifold behind the throttle element while the fuel machine is running and are fed to the internal combustion engine for combustion. In downtimes, or when the tank ventilation valve is closed, or if, due to the load conditions of the internal combustion engine, sufficient vacuum is not built up in the intake manifold to allow the fuel vapors to be extracted, these are adsorbed in the adsorption filter.
• the limited space available for the adsorption filter means that the storage capacity is limited.
• the adsorption filter is flushed with fresh air, which is fed to the filter via a ventilation line connected to the atmosphere.
• the fresh air first reaches the adsorption filter through a shut-off valve controlling the ventilation line, where it absorbs the fuel vapors and supplies it to the internal combustion engine through the intake line and the intake manifold.
• the shut-off valve When the shut-off valve is closed and the tank ventilation valve is closed, the fuel tank, the filter line and the adsorption filter should form a unit that is hermetically sealed from the atmosphere for functional and environmental reasons.
• a negative pressure is set in relation to the environment in this unit (see DE-OS 40 03 751). If one of the components has a leak, the negative pressure cannot be maintained because air flows in from outside into this unit.
• the shut-off valve is opened, and when the tank ventilation valve is open, fresh air flows through the shut-off valve into the adsorption filter, regenerates the adsorption filter and is fed to the internal combustion engine as a mixed stream. With such a shut-off valve there is a risk that condensate will accumulate in its electrical area and lead to malfunctions or failure of the shut-off valve.
• shut-off valve there is the risk that it will be kept closed unintentionally due to a malfunction of the electromagnetic circuit and that an inadmissibly high excess pressure will build up in the fuel tank, the lines and the adsorption filter when the tank ventilation valve is closed, which leads to malfunctions.
• the fresh air flowing into the adsorption filter contains impurities, e.g. in the form of dust and dirt particles. These impurities are partially deposited in the interior of the shut-off valve, for example on the sealing surfaces of a valve closing body and a valve seat. When the valve is closed again, the deposited impurities prevent the shut-off valve from closing again tightly. If the unit is now to be subjected to a further leak test, air penetrates from outside through the non-tight shut-off valve into the unit which is under negative pressure. This means that it is no longer possible to clearly state whether the leak is due to a possible leak somewhere in the unit or the non-tight shut-off valve.
• the venting device according to the invention for a fuel tank of an internal combustion engine with the characterizing features of the main claim has the advantage that, despite the use of a fine-pored particle filter, it is ensured that only a negligibly low negative pressure is caused by the particle filter in the adsorption filter.
• the large flow cross section of the particle filter reduces the pressure drop of the medium flowing through the particle filter.
• the particle filter has a long service life due to the large surface area.
• the ventilation line running at least partially outside the adsorption filter enables simple assembly of the shut-off valve and the ventilation line.
• the electrical connections required for the control do not have to be routed to the outside through housing openings that are sealed off from the environment.
• shut-off valve design and arrangement of the shut-off valve is advantageous in such a way that condensates can flow off without impairing the function of the shut-off valve. It is also advantageous if the magnetic circuit of the shut-off valve is designed so that the shut-off valve is pressed against the magnetic force at a predetermined excess pressure in the fuel tank.
• the arrangement of at least one baffle in the adsorption filter advantageously allows a more intensive and longer flow through the adsorption medium.
• FIG. 1 shows a first exemplary embodiment of a ventilation device designed according to the invention
• FIG. 2 shows a second exemplary embodiment of a ventilation device partially designed according to the invention
• FIG. 3 shows a third exemplary embodiment of a ventilation device designed according to the invention and shown partially.
• FIG. 1 shows schematically a ventilation device for a fuel tank of an internal combustion engine, for example for a motor vehicle.
• the ventilation device comprises, inter alia, an adsorption filter 1, a fuel tank 2 and a tank ventilation valve 3.
• the fuel tank 2 is filled via a filler neck 6, which is closed with a tank cap 7.
• the adsorption filter 1 and the fuel tank 2 are connected to one another by a filter line 8, which starts from a region of the fuel tank 2 in which the vaporous portions of the fuel preferably collect.
• the liquid phase changes into the vaporous phase at the values corresponding to the vapor pressure curve and enriches the space above the liquid phase with fuel vapor.
• a commercially available fuel for a known, for example, mixture-compressing, externally ignited internal combustion engine can contain portions whose saturation temperature is below 40 ° C., which are thus already completely evaporated at a fuel temperature of 40 ° C.
• the vapor pressure of the fuel corresponds to the sum of the partial pressures of the vaporous portions of the fuel.
• the vapor pressure of a fuel used for a known, for example, mixture-compressing spark-ignition internal combustion engine can reach values of up to 1.9 bar, that is to say above the standard pressure of approximately 1.013 bar. With increasing temperature or falling ambient pressure, the evaporation rate increases to the point at which an equilibrium is reached again.
• the adsorption filter 1 is connected by a suction line 16, which is controlled by the tank ventilation valve 3.
• the suction line 16 ends in the suction pipe 13 in a section lying downstream of a throttle element 18, in which there is negative pressure depending on the load.
• the end of the suction line 16 facing the adsorption filter 1 is located on a suction line connection 20 of a, for example, disk-shaped housing cover 21, which closes, for example, a correspondingly cylindrical housing 22 of the adsorption filter 1 on one side.
• the housing cover 21 is tightly connected to the housing 22 and the suction line 16.
• An annular housing section 24 of the housing 22, the housing cover 21 and the filter insert 23 delimit a first storage space 26 which is connected to the suction line 16 through the suction line connection 20 and to the suction pipe 13 when the tank ventilation valve 3 is open.
• a second filter insert 27 covers the entire inner cross section of the housing 22 of the adsorption filter 1 at an axial distance from it.
• an adsorption space 28 is delimited, which is completely or only partially filled with an adsorption medium 31, for example activated carbon.
• the adsorption space 28 is connected to the first storage space 26 through the gas-permeable first filter insert 23.
• the filter line 8 connecting the fuel tank 2 to the adsorption filter 1 is guided through the housing cover 21 by means of a filter connection 32 and tightly connected to the housing cover 21.
• the first storage space 26 is penetrated by the filter line 8 in its entire axial extent.
• the filter line 8 penetrates the first filter insert 23 in an opening 33 and ends e.g. in the adsorption space 28 filled with activated carbon.
• the fuel tank 2 and the adsorption space 28 are thus directly connected through the filter line 8.
• a gas-tight partition 36 penetrates the inner cross section of the housing 22 on the side of the second filter insert 27 facing away from the adsorption space 28 and is tightly connected to the housing 22.
• a second storage space 37 is delimited by a housing section 29 of the housing 22, the second filter insert 27 and the partition wall 36.
• the first storage space 26, the adsorption space 28 and the second storage space 37 are connected to one another in a gas-permeable manner by the first 23 and second filter insert 27.
• the partition wall 36 and an annular end section 30 of the housing 22 form a cup-shaped filter space 38, which is open to the atmosphere and is completely covered by a fine-pored particle filter 41 at its end opposite the partition wall 36.
• the particle filter 41 thus extends over the entire inner cross section of the housing 22 and separates the filter space 38 in a gas-permeable manner from the atmosphere and is able to retain the finest dirt particles from the atmosphere.
• An inner wall 39 encloses the inner cross section of the housing 22, so that the particle filter 41 extends at least over the clear width of the housing 22 delimited by the inner wall 39.
• the particle filter 41 is thus formed across a large area transversely to the regeneration air flow and thus causes only a slight pressure drop below 5 mbar at an air flow of approx. 3 m / h.
• the housing cover 21, the housing 22 and the partition 36 form a closed space which has an external connection through the suction line connection 20, the filter line connection 32 and a first ventilation line connection 42.
• the housing 22 has a second vent line connector 45 which, for example, the same angle 'coordinate with respect to the housing 22 zylindri ⁇ rule as the first vent line 42 has terminal.
• One end of a U-shaped ventilation line 46 is pushed tightly into each of the two ventilation line connections 42, 45, so that the filter space 38 and the second storage space 37 are connected to one another.
• the ventilation line 46 is sealed off from the housing 22 by elastic sealing elements 47, 48, for example O-rings.
• a shut-off valve 51 for example an electromagnetically actuable valve, controls the ventilation line 46.
• the shut-off valve 51 In order to avoid that in the event of the tank ventilation valve 3 and shut-off valve 51 being closed accidentally or due to malfunctions, an overpressure generated by fuel vapors to burst the fuel tank 2, the filter line 8, the suction line 16 or the housing 22 of the adsorption filter 1, the shut-off valve 51 must be able to be positively opened by an overpressure.
• the magnetic circuit 54 of the shut-off valve 51 must be designed such that, in the case of a predetermined excess pressure in the adsorption filter 1, for example 0.3 bar, the pressure force acting on a valve closing part 55 is sufficient to do this when the magnetic circuit 54 is excited in the closed position of the shut-off valve 51 moved valve closing part 55 against the magnetic force in the open position of the shut-off valve.
• the shut-off valve 51 can, as shown in FIG. 1, be designed with a valve closing part 55, which is opened by a return spring 49 in the non-excited state of the magnetic circuit 54 in the open position in the direction of the lower connection connected to the filter chamber 38
• the valve closing part 55 is pushed onto the valve seat 50 in the direction of the upper connecting piece 52 and only with such a force that a pressure force generated by an overpressure of about 0.3 bar in the adsorption filter 1 is sufficient to close the valve closing part 55 to push against the magnetic force away from the valve seat 50 in the direction of the lower connecting piece 53. Due to the now open shut-off valve 51, the pressure in the adsorption filter 1 and fuel tank 2 can decrease.
• the shut-off valve 51 can also be formed with a valve closing part which, when the magnetic circuit is excited, is displaced against the force of a return spring in the direction from the upper connecting piece 52 to the lower connecting piece 53 and thereby comes into contact with the valve seat until one comes through an overpressure of approx.
• valve closing part In the non-excited state of the magnetic circuit, the valve closing part is moved by the return spring in the direction of the upper connecting piece 52, ie away from the valve seat, in the opening position of the shut-off valve.
• a broken valve 51 * is also shown in dashed lines in FIG. 1, which is arranged within the filter space 38 and for which the same statements regarding function and structure apply as for the shutoff valve 51.
• the ventilation connections 42 and 45 in the housing 22 are closed.
• the ventilation connection 42 ' penetrates the partition 36 and is connected to the upper connection piece 52 * of the shut-off valve 51' which runs inclined upwards.
• a lower nozzle can be dispensed with in the shutoff valve 51 ', since the shutoff valve 51' which is arranged vertically can be open at the bottom in the direction of the particle filter 41.
• the shut-off valve 51 thus also fulfills the function of a safety valve.
• the shut-off valve 51 is opened in the de-energized state in order to prevent the power supply, e.g. after an accident, to avoid an increase in pressure in the fuel tank 2.
• To open the shut-off valve 51 in the de-energized state e.g. the return spring 49.
• the shut-off valve 51 is oriented in such a way that the magnetic circuit 54 is arranged at the point of the shut-off valve 51 which is the highest in the gravitational field.
• the outflow of condensate from the second storage space 37, the ventilation line 46 and the shut-off valve 51 in the direction of the atmosphere is favored in that the valve closing part 55 along a vertical opening and closing movement a vertical axis 56 and the valve seat 50 is concentric to this vertical axis 56.
• the magnetic circuit 54 lies above the valve seat 50 and, for example, also above the upper connector 52 or above the air duct in the shut-off valve 51 from the upper connector 52 to the valve seat 50.
• the air flowing into the adsorption filter 1 from the atmosphere is first cleaned of impurities, for example in the form of dust, by the particle filter 41.
• the fresh air flow experiences a pressure drop through the particle filter 41, which propagates directly into the fuel tank as a negative pressure and there increases the evaporation rate of the fuel unintentionally.
• a filling gun sealing against the filler neck 6 is used.
• the fuel vapors are displaced by the adsorption filter 1 and cause, among other things, a pressure drop at the particle filter 41, which leads to an increase in pressure at the fuel nozzle, which unintentionally triggers the automatic shut-off mechanism of the fuel nozzle when a certain size is reached.
• the cross-sectional area of the particle filter 41 significantly influences the pressure drop caused on the particle filter 41.
• the pore size In order to achieve adequate cleaning of the fresh air drawn in, the pore size must be very small, that is, a small-pored particle filter 41 must be selected, as a result of which the pressure drop increases sharply. This undesirable side effect can be compensated for by a large cross-sectional area, so that the risk of unintentional triggering of the switch-off mechanism of the fuel nozzle as well as the increase in the evaporation rate of the fuel in the fuel tank 2 is reduced.
• the particle filter 41 is given a large cross-sectional area with a pressure drop of a reasonable size in that the particle filter 41 extends at least over the entire inner cross section of the housing 22.
• the shut-off valve 51 or 51 * is closed. Due to the negative pressure prevailing in the intake manifold, a negative pressure is established in the fuel tank 2, the filter line 8, the adsorption filter 1 and the suction line 16. The tank ventilation valve 3 is then closed.
• a pressure sensor 80 is used to determine the pressure.
• tion filter 1 is arranged and protrudes into one of the rooms 26, 28 or 37.
• the pressure sensor 80 like the tank ventilation valve 3 and the shutoff valve 51 or 51 ', is connected to an electronic control unit 81. If one of these components or a connection has a leak, air flows in the direction of the negative pressure areas and leads to a pressure equalization, so that the negative pressure can only be maintained for a short time and the pressure sensor 80 transmits a changing signal to the control unit 81.
• both the shut-off valve 51 and the tank ventilation valve 3 are closed tightly. If one of the valves mentioned does not close completely, air penetrates into the shut-off space through the leaky valve. It is no longer possible to make a reliable statement as to the extent to which the system has a leak or whether the air penetrates through a valve which is not fully closed.
• the shut-off valve 51 through which the fresh air regenerating the adsorption filter 1 flows first, is particularly susceptible. The risk is particularly great here that contaminants of the air settle in the shut-off valve 51 and prevent a completely tight closing.
• the large-area particle filter 41 which is integrated in the housing 22 and covers the inner cross section, prevents the shut-off valve 51 from being contaminated without impairing the general functionality of the ventilation device through an excessive drop in pressure of the fresh air flowing through it.
• FIGS. 2 and 3 show two further exemplary embodiments of a ventilation device designed according to the invention with an adsorption filter for a fuel tank, the tank ventilation valve and the intake pipe having been omitted. Compared to the exemplary embodiment according to FIG.
• the adsorption filter 1 shown in FIG. 2 has a first storage space 26, which is separated from the adsorption space 28 by the first filter insert 23, and a second storage space 37, which deviates from the exemplary embodiment shown in FIG. 1 by at least partially with the Adsorption medium 31 filled adsorption space 28 is separated by the second filter insert 27 and a first guide plate 60.
• the second storage space 37 extends only partially over the entire inner cross section of the housing 22.
• the first guide plate 60 projects from the partition 36, for example in the longitudinal direction of the inner wall 39 of the housing 22 and perpendicular to the partition 36 ⁇ way into the adsorption space 28 and ends at a distance from the first filter insert 23, so that a free cross section remains between the first guide plate 60 and the first filter insert 23.
• the first guide plate 60 is at a short distance from the right inner wall 39 of the housing 22, for example.
• a second baffle 61 extends partially from the housing cover 21, for example perpendicularly to the housing cover 21, into the adsorption space 28 as far as at least into the adsorption medium 31.
• a cross section remains free between the end of the second guide plate 61 facing the partition 36.
• the adsorption space 28 is divided by the two, for example parallel baffles 60, 61 into three, for example two approximately 57, 58 of approximately the same size and a chamber 59 smaller by the volume of the storage space 37, which are separated from one another by those between the first baffle 60 and the first filter insert 23 and the second guide sheet 61 and the partition 36 free cross sections are connected.
• the smaller right chamber 59 is gas-permeable to the first storage space 26 through the first filter insert 23 and connected to the second storage space 37 through the second filter insert 23.
• the suction line connection 20 and the filter line connection 32 are arranged in the area of the housing cover 21, which partially delimits the left chamber 57, so that there is the greatest possible distance between the entry of the fresh air at the second filter insert 27 and the suction line connection 20, that is to say a large amount of adsorption medium 31 flows around.
• shut-off valve 51 already described for the exemplary embodiment according to FIG. 1 is inserted in the manner explained there with the nozzles 52 and 53 in ventilation line connections 42 and 45, so that the shut-off valve 51 connects the filter space 38 through the large-area particle filter 41 is limited, and the second storage space 37 can be produced.
• the housing 22 of the adsorption filter 1 according to FIG. 3 has a lateral indentation 62, the size of which is such that the shut-off valve 51 and the ventilation line 46 can be accommodated therein without protruding beyond the outline of the housing 22 .
• a longitudinal wall 65 of the indentation 62 parallel to the inner wall 39 of the housing 22 the two ventilation line connections 42 to the second storage space 37 and 45 to the filter space 38 are arranged, into which the connections 52 and 53 of the ventilation line 46 are inserted.
• a lower guide plate 63 Arranged between the partition wall 36 and the first filter insert 23 is a lower guide plate 63, for example running parallel to the latter, starting from the inner wall 39 at the indentation 62 and projecting into the adsorption space 28 at a distance from the first filter insert 23 the entire cross section of the housing 22 to the opposite overlying inner wall 39 extends. A cross section remains free between the end of the lower guide plate 63 lying in the adsorption space 28 and the inner wall 39 of the housing 22.
• the adsorption space 28 is divided by the lower guide plate 63 into a lower chamber 67 on the partition 36 and an upper chamber 68 on the first filter insert 23.
• the second filter insert 27 is arranged between the lower guide plate 63 and the partition wall 36 and, together with the partition wall 36, the lower guide plate 63 and the housing 22, delimits the second storage space 37.
• An upper baffle plate 64 partially projects into the adsorption space 28, but at least into the adsorption medium 31 and divides the upper chamber 68 into a left-hand chamber 69 and a right-hand chamber 70.
• the suction line connection 20 and the filter line connection 32 are in that Arranged region of the housing cover 21, which lies above the right chamber 70.
• the upper guide plate 64 ends above the lower guide plate 63, so that a vertical free cross section remains between the upper guide plate 64 and the lower guide plate 63, via which gas exchange between the chambers 69 and 70 can take place. In this way, the greatest possible distance is reached between the entry of the fresh air in the second storage space 37 and the suction line connection 20 and thus a lot of adsorption medium 31 flows around.
• the shut-off valve 51 which is inserted into the ventilation line connections 42 and 45 of the indentation 62 by means of the connecting pieces 52 and 53, is included in the contour of the housing 22 and is therefore better protected against damage.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Transportation (AREA)
• General Engineering & Computer Science (AREA)
• Cooling, Air Intake And Gas Exhaust, And Fuel Tank Arrangements In Propulsion Units (AREA)
• Supplying Secondary Fuel Or The Like To Fuel, Air Or Fuel-Air Mixtures (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6446436

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (19)

Citations (6)

Family Cites Families (18)

• 1991
  • 1991-12-06 DE DE4140258A patent/DE4140258C1/de not_active Revoked
• 1992
  • 1992-11-13 DE DE59203690T patent/DE59203690D1/de not_active Expired - Lifetime
  • 1992-11-13 US US08/098,344 patent/US5450833A/en not_active Expired - Fee Related
  • 1992-11-13 JP JP50968793A patent/JP3320722B2/ja not_active Expired - Fee Related
  • 1992-11-13 KR KR1019930702059A patent/KR100265311B1/ko not_active IP Right Cessation
  • 1992-11-13 WO PCT/DE1992/000948 patent/WO1993010993A1/de active IP Right Grant
  • 1992-11-13 EP EP92923382A patent/EP0570552B1/de not_active Expired - Lifetime

Patent Citations (6)

Non-Patent Citations (2)

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