JPH07310609A - Vaporized fuel treating device - Google Patents

Abstract

PURPOSE:To simplify a mechanism to liquefy vaporized fuel and to prevent incurring of a cooling energy loss. CONSTITUTION:A canister housing 34 in which granular activated coals 55 and 56 are contained and a fuel tank 23 are interconnected through a first passage 30. A housing 34 and the intake air passage 7 of an engine are interconnected through a second passage 31 and an on-off valve 32 is located in the middle of the passage 31. During closing of an on-off valve 32, vaporized fuel generated from liquid fuel 20 in the fuel tank 23 is adsorbed to the activated coals 55 and 56 and during opening of the on-off valve 32, fuel adsorbed to the activated coals 55 and 56 is eliminated and discharged in the intake air passage 7. A liquid fuel storage container 43 is embedded in the activated coals 55 in the housing 34 and when vaporized fuel from the fuel tank 23 passes through the storage container 43, fuel is eliminated from the activated coals 55 and 56 and the vaporized fuel is cooled through endothermic operation occurring when fuel is eliminated from the activated coals 55 and 56 and gasified, and stored in a liquid state in the storage container 43.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporated fuel processing apparatus for processing evaporated fuel generated from liquid fuel in a fuel tank without releasing it to the atmosphere.

[0002]

2. Description of the Related Art Conventionally, in a vehicle equipped with, for example, a gasoline engine, part of the liquid fuel (gasoline) in the fuel tank becomes vapor (vaporized fuel) as the temperature rises. In order to prevent the release of this evaporated fuel to the atmosphere, many vehicles are equipped with an evaporated fuel processing device. In this processing apparatus, a canister housing containing an adsorbent such as activated carbon and a fuel tank are connected by a first passage, and a canister housing and an intake passage of an internal combustion engine are connected by a second passage. An on-off valve is provided in the middle of the second passage. Then, when the on-off valve is closed, the evaporated fuel from the fuel tank is adsorbed by the adsorbent, and when the on-off valve is opened, the fuel adsorbed by the adsorbent is desorbed and released into the intake passage.

In the above evaporative fuel processing apparatus, when a large amount of evaporative fuel flows out from the fuel tank when traveling uphill in summer, etc., the entire amount cannot be adsorbed by the adsorbent. May be released.

Therefore, various techniques have been proposed to prevent the evaporative fuel from being released into the atmosphere even in such a case. For example, in Japanese Utility Model Laid-Open No. 63-92064, an evaporated fuel liquefaction mechanism for cooling and liquefying evaporated fuel is provided in the middle of the first passage, and the fuel liquefied by the mechanism is circulated to a fuel tank. There is. The vapor separator of the evaporative fuel liquefaction mechanism includes a plurality of condensing pipes that communicate between the upper chamber and the lower chamber, and a water jacket that surrounds the condensing pipes. Cooling water is introduced into the water jacket to cool the condenser tube. As the cooling water, for example, drain water dropped from the evaporator of the air conditioner is used.

According to this technique, the evaporated fuel from the fuel tank is cooled and liquefied when passing through the condensing pipe. Only the vaporized fuel that has not been liquefied is adsorbed by the adsorbent. Therefore, the evaporated fuel having a processing capacity higher than that of the adsorbent is not guided to the adsorbent, and the atmospheric release of the evaporated fuel is prevented.

[0006]

However, in the prior art, cooling water is used to liquefy the evaporated fuel as described above. Therefore, a vapor separator including an upper chamber, a lower chamber, a condenser pipe, a water jacket, and the like, and a conduit for guiding drain water from the evaporator of the air conditioner to the water jacket are required. As a result, the structure of the evaporated fuel liquefaction mechanism becomes complicated. Further, since cooling water is used for liquefaction, there is a problem that cooling energy is lost.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to make it possible to liquefy evaporated fuel without using cooling water, simplify the mechanism for liquefaction, and prevent loss of cooling energy. An object of the present invention is to provide an evaporated fuel processing device that can achieve the above.

[0008]

In order to achieve the above object, a first aspect of the present invention is to connect a canister housing containing an adsorbent and a fuel tank through a first passage. , The canister housing and the intake passage of the internal combustion engine are connected by a second passage, and an opening / closing valve is provided in the middle of the second passage. When the opening / closing valve is closed,
Evaporative fuel processing in which the evaporated fuel generated from the liquid fuel in the fuel tank is adsorbed by the adsorbent, and when the on-off valve is opened, the fuel adsorbed by the adsorbent is desorbed and released into the intake passage. In the device, the liquid fuel storage container is embedded in the adsorbent in the canister housing, and when the evaporated fuel from the fuel tank passes through the storage container, the fuel is desorbed from the adsorbent. The vaporized fuel is cooled by the endothermic action at the time of vaporization and stored in a liquid state in the storage container.

According to a second aspect of the present invention, in addition to the structure of the first aspect, the fuel desorbed from the adsorbent and vaporized inside the canister housing is directed toward the liquid fuel storage container. A flow changing member that changes the flow direction of the fuel is provided so that the fuel flows.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the invention, an operating state detecting means for detecting an operating state of the internal combustion engine and the second passage are passed. When the operating state by the operating state detecting means and the evaporative fuel concentration detecting means for detecting the concentration of the evaporative fuel satisfies a predetermined condition, the evaporative fuel concentration detecting operation is performed after the on-off valve is opened for a certain period of time. There is provided a first control means for closing the opening / closing valve so that the closing time of the opening / closing valve becomes longer as the fuel concentration by the means becomes smaller, and then opening the opening / closing valve again.

According to a fourth aspect of the present invention, in addition to the configuration of the first or second aspect, the fourth aspect is provided closer to the canister housing than the on-off valve in the second passage and has a predetermined volume. Operation of the negative pressure air storage container, an auxiliary opening / closing valve that is provided closer to the canister housing than the negative pressure air storage container in the second passage, and that opens and closes the second passage, and the operation of the internal combustion engine When the operating state detecting means for detecting the state and the operating state by the operating state detecting means satisfy a predetermined condition, both the on-off valve and the auxiliary on-off valve are opened, and the operating state by the operating state detecting means. When the above condition is not satisfied, the second control means for closing the auxiliary opening / closing valve while keeping the opening / closing valve open and storing the negative pressure air in the intake passage in the negative pressure air storage container; 2 control After closing the auxiliary opening / closing valve by the step, the opening / closing valve is closed when a preset time elapses, and then, when the internal combustion engine is stopped, the auxiliary opening / closing valve is opened with the opening / closing valve closed. Third control means for guiding the negative pressure air in the negative pressure air storage container into the canister housing.

[0012]

When the on-off valve of the first invention is closed, the evaporated fuel generated from the liquid fuel in the fuel tank flows into the canister housing through the first passage and is adsorbed by the adsorbent. Further, when the on-off valve is opened, the fuel adsorbed by the adsorbent is desorbed to become gas and is discharged to the intake passage of the internal combustion engine through the second passage.

In the process of such adsorption and desorption, the evaporated fuel from the fuel tank passes through the liquid fuel storage container embedded in the adsorbent. During this passage, the evaporated fuel in the storage container is cooled by the endothermic action when the fuel is desorbed from the adsorbent and vaporized. By this cooling, the evaporated fuel is liquefied and stored in the storage container in a liquid state.

Therefore, the amount of the evaporated fuel adsorbed by the adsorbent after passing through the storage container is reduced by the stored amount. It is possible to prevent more than the amount of evaporated fuel that can be adsorbed by the adsorbent from being introduced into the adsorbent. Further, since the evaporated fuel is cooled and liquefied by the endothermic action when the evaporated fuel is separated from the adsorbent, it is not necessary to separately provide a mechanism for this liquefaction.

In the second invention, in addition to the operation of the first invention, the flow of the fuel desorbed from the adsorbent and vaporized is changed by the flow changing member arranged in the canister housing. By this change, the vaporized fuel flows toward the liquid fuel storage container, and the evaporated fuel in the storage container is cooled. Therefore, as compared with the case where such a flow changing member is not provided, a larger amount of evaporated fuel in the storage container is cooled and liquefied.

In the third invention, in addition to the operation of the first or second invention, the operating state of the internal combustion engine is detected by the operating state detecting means, and the concentration of the evaporated fuel passing through the second passage is the evaporated fuel concentration. It is detected by the detection means. The first control means opens the open / close valve when the operating state by the operating state detecting means satisfies a predetermined condition. The first control means closes the opening / closing valve such that the opening / closing valve closing time becomes longer as the fuel concentration by the evaporated fuel concentration detecting means becomes smaller after a lapse of a certain time from the opening of the valve. When the valve closing time has elapsed, the first control means opens the opening / closing valve again.

Therefore, when the fuel vapor concentration is low,
The evaporative fuel is adsorbed by the adsorbent for a longer period than when it is large. As a result, a large amount of fuel vapor will be adsorbed by the adsorbent. Therefore, when the on-off valve is opened again, a large amount of fuel adsorbed on the adsorbent is desorbed at once, and most of the evaporated fuel in the liquid fuel storage container is cooled and liquefied.

By the way, during operation of the internal combustion engine, the temperature of the liquid fuel in the fuel tank generally rises and its evaporation becomes active. It is considered that the most amount of evaporated fuel is generated immediately after the operating internal combustion engine is stopped. Therefore, if the fuel adsorbed by the adsorbent is desorbed immediately after this stop, a large amount of the evaporated fuel in the liquid fuel storage container can be cooled and liquefied. But,
When the internal combustion engine is stopped, no negative pressure is generated in the intake passage, and it is difficult to guide negative pressure air to the canister housing.

On the other hand, in the fourth invention, the first
Alternatively, in addition to the function of the second invention, the operating state of the internal combustion engine is detected by the operating state detecting means. When the detected operating condition satisfies a predetermined condition, the second control means opens both the on-off valve and the auxiliary on-off valve. Therefore, the fuel adsorbed by the adsorbent in the canister housing is desorbed and discharged to the intake passage via the second passage, the auxiliary opening / closing valve, the negative pressure air storage container, and the opening / closing valve.

The second control means closes the auxiliary opening / closing valve while keeping the opening / closing valve open when the operating condition of the internal combustion engine does not satisfy the above condition. Then, the negative pressure air in the intake passage is stored in the negative pressure air storage container.

The third control means closes the opening / closing valve when a preset time elapses after the auxiliary opening / closing valve is closed by the second control means. Therefore, since the on-off valve and the auxiliary on-off valve are closed, the negative pressure air in the negative pressure air storage container is sealed in the same container.

When the internal combustion engine is stopped thereafter, the third control means opens the auxiliary opening / closing valve while keeping the opening / closing valve closed. Then, the negative pressure air in the negative pressure air storage container is introduced into the canister housing, the fuel adsorbed by the adsorbent is desorbed from the adsorbent, and is introduced into the negative pressure air storage container. Due to the endothermic action at the time of desorption, many evaporated fuels in the liquid fuel storage container are cooled and liquefied.

[0023]

【Example】

(First Embodiment) A first embodiment embodying the first and second inventions will be described below with reference to FIGS.

FIG. 1 is a schematic configuration diagram of a gasoline engine (hereinafter, simply referred to as an engine) 1 as an internal combustion engine mounted on a vehicle. Cylinder block 1a of engine 1
, A plurality of cylinders (only one is shown in the figure) 2 are arranged in parallel in the thickness direction of the paper. A piston 3 is reciprocally housed in each cylinder 2. Each piston 3 is connected to a crankshaft 5 by a connecting rod 4.

A combustion chamber 6 is formed above each piston 3, and an intake passage 7 and an exhaust passage 8 are communicated therewith. The intake port 9 between each combustion chamber 6 and the intake passage 7 is
It is opened and closed by an intake valve 11 attached to the cylinder head 1b. The exhaust port 12 between each combustion chamber 6 and the exhaust passage 8 is opened and closed by an exhaust valve 13 attached to the cylinder head 1b.

The intake passage 7 is provided with a throttle body 14, a surge tank 15, and an intake manifold 16, through which air outside the engine 1 is transferred to the combustion chamber 6.
Is taken into. A throttle valve 17 is rotatably supported by a shaft 18 in the throttle body 14.
The shaft 18 is connected to an accelerator pedal (not shown) by a cable or the like. Then, when the driver depresses the accelerator pedal, the depressing operation is transmitted to the shaft 18 via a cable or the like, and the throttle valve 17 causes the shaft 1 to move.
It rotates together with 8. The passage area of the intake passage 7 changes according to the rotation angle of the throttle valve 17, and the amount of air flowing through the intake passage 7 is adjusted.

An electromagnetic fuel injection valve 19 for supplying fuel to each combustion chamber 6 is attached to the intake manifold 16. Each fuel injection valve 19 is connected to a fuel pump 24 in a fuel tank 23 by a fuel pipe 21 and a delivery pipe 22. The fuel pump 24 sucks and discharges the liquid fuel (gasoline) 20 stored in the fuel tank 23. The liquid fuel 20 discharged from the fuel pump 24 passes through the fuel pipe 21, is distributed by the delivery pipe 22, and is supplied to each fuel injection valve 19.
A fuel filter 25 for capturing foreign matter in the liquid fuel 20 is provided in the middle of the fuel pipe 21.

The delivery pipe 22 and the fuel tank 23 are communicated with each other by a return pipe 26, and a pressure regulator 27 is arranged in the middle of the return pipe 26. The pressure regulator 27 adjusts the pressure of the fuel pumped to each fuel injection valve 19 so as to be higher than the pressure of the intake air at the intake port 9 by a constant pressure, and the surplus fuel is passed through the return pipe 26 to the fuel tank. Return to 23.

The fuel injection valve 19 is provided with a needle valve, a solenoid coil, etc. When the solenoid coil is energized, the needle valve moves to open the injection port. With the opening of the injection port, high-pressure fuel is injected from the fuel pump 24. Then, each fuel injection valve 19
The air-fuel mixture consisting of the fuel injected from the air and the air introduced into the intake passage 7 is introduced into the combustion chamber 6 through the intake port 9 when the intake valve 11 is opened.

A spark plug 28 is attached to the cylinder head 1b, and the air-fuel mixture introduced into each combustion chamber 6 is burned by the ignition of the spark plug 28. Due to this combustion, the piston 3 operates, and its reciprocating motion is converted into a rotary motion by the connecting rod 4, and the crankshaft 5 is rotationally driven. The gas (exhaust gas) generated by the combustion in the combustion chamber 6 is led from the exhaust port 12 to the exhaust passage 8 when the exhaust valve 13 is opened.

The vehicle is equipped with the liquid fuel 2 in the fuel tank 23.
Evaporative fuel processing device (hereinafter, simply referred to as processing device) for processing the evaporated fuel generated with the temperature rise of 0 2
9 is provided. The processing device 29 includes a canister housing (hereinafter, simply referred to as a housing) 34 that stores an adsorbent, and a first passage 30 that connects the housing 34 and the fuel tank 23. Further, the processing device 29 includes a second passage 31 that connects a portion of the intake passage 7 downstream of the throttle valve 17 (for example, the surge tank 15 or the like) and the housing 34.

An electromagnetic on-off valve 32 is provided in the middle of the second passage 31. The on-off valve 32 opens and closes in response to an electric signal from the outside, and opens and closes the second passage 31.

As shown in FIG. 2, the inside of the housing 34 is divided into a main chamber 36 and a sub chamber 37 by a partition plate 35. A through hole 38 is formed in a lower portion of the partition plate 35, and the main chamber 36 and the sub chamber 37 are communicated with each other through the through hole 38.

At the upper part of the housing 34, an atmosphere port 39 for taking in air (atmosphere) outside the housing 34 into the sub chamber 37 is opened. Also, the housing 34
A port 41 for communicating the upper portion of the main chamber 36 and the second passage 31 is opened at the side portion of the. Therefore, the atmosphere taken into the housing 34 from the atmosphere port 39 can flow into the second passage 31 through the sub chamber 37, the through hole 38, the main chamber 36, and the port 41.

On the other hand, in order to guide the evaporated fuel generated in the fuel tank 23 into the housing 34, a guide pipe 42, a liquid fuel storage container (hereinafter simply referred to as a storage container) 43, and a guide pipe 44 are provided inside and outside the housing 34. And pressure control valve 4
5 are provided. The storage container 43 is arranged substantially in the center of the main chamber 36. The upper surface and the bottom surface of the storage container 43 are flat and are substantially orthogonal to the direction (vertical direction) in which the fuel desorbed from the adsorbent and vaporized flows.

The pressure regulating valve 45 comprises a valve case 46, a diaphragm 47, a valve body 48 and a coil spring 49.
A tubular portion 46a is provided on the bottom of the valve case 46 so as to project upward. The diaphragm 47 is stretched in the valve case 46 and divides the case 46 into two parts, an upper part and a lower part. Disc 4
8 is formed larger than the upper end opening of the tubular portion 46a, and is fixed to the central portion of the diaphragm 47.

A hole 46b is formed in the upper part of the valve case 46, and the space above the diaphragm 47 in the valve case 46 is open to the atmosphere. Coil spring 49
Is disposed in a space above the diaphragm 47 in the valve case 46, and always urges the valve body 48 downward in the direction of closing the tubular portion 46a.

The inside of the storage container 43 and the first passage 30 are connected by a guide tube 42. In addition, the storage container 43 and the space below the diaphragm 47 of the valve case 46 are connected by a guide tube 44. And
When the urging force of the coil spring 49 overcomes the atmospheric pressure in the storage container 43, the tubular body 46a is closed by the valve body 48. When the atmospheric pressure in the storage container 43 rises and overcomes the biasing force of the coil spring 49, the valve body 48 is lifted and the tubular portion 46a is opened.

In the housing 34, upper net members 51 and 52 are stretched at a position slightly lower than the port 41 and higher than the upper surface of the storage container 43. Further, lower net materials 53 and 54 are stretched at a position lower than the bottom surface of the storage container 43 and slightly higher than the through hole 38. Between the upper and lower net materials 51, 53 in the main chamber 36, the portion other than immediately above and directly below the storage container 43 is filled with granular main activated carbon 55 forming a part of the adsorbent. Therefore, the storage container 43 is buried in the main activated carbon 55. Similarly, between the upper and lower net materials 52 and 54 in the sub chamber 37, granular sub activated carbon 56 that constitutes an adsorbent together with the main activated carbon 55 is filled.

Both of the activated carbons 55 and 56 have a function of adsorbing and releasing the evaporated fuel. Heat is generated when the evaporated fuel is adsorbed by the activated carbons 55 and 56 and changed to a liquid, and heat is absorbed when the liquid fuel adsorbed on the activated carbons 55 and 56 is desorbed (purged) and changed to a gas (vaporized). Occur.

In this embodiment, by utilizing this endothermic effect, the evaporated fuel in the storage container 43 is cooled and liquefied. That is, the guide tubes 42 and 44, the storage container 43
The pressure adjusting valve 45 has a function of guiding the evaporated fuel into the housing 34, and also has a function of liquefying the evaporated fuel. The internal space of the storage container 43 is
It serves as a liquid storage chamber for storing liquefied fuel.

As described above, the sub-chamber 37 is provided separately from the main chamber 36, and the sub-activated carbon 56 is filled therein to prevent the vaporized fuel from being released to the atmosphere. More specifically, when the evaporated fuel is left adsorbed on the main activated carbon 55, the fuel gradually moves to the non-adsorbed main activated carbon 55 side. As a result, the fuel concentration between the upper and lower net materials 51 and 53 becomes uniform. In this state, when the evaporated fuel enters the main chamber 36, the uniformly adsorbed fuel is pushed downward. Therefore, this extruded fuel is fed to the secondary activated carbon 56
To re-adsorb and prevent the fuel from being released into the atmosphere.

Further, a plurality of fins 58 as flow changing members are arranged around the storage container 43 in the main chamber 36. These fins 58 have a flat plate shape, and are arranged in an inclined state so as to be higher toward the storage container 43 side. This arrangement is made so that the air cooled by the endothermic action when the fuel is desorbed from the main activated carbon 55 flows toward the storage container 43,
This is to promote the liquefaction of the evaporated fuel within the fuel cell 3.

Immediately above and below the bottom surface of the storage container 43, mesh members 62 and 63 for forming spaces 59 and 61 not filled with the main activated carbon 55 are arranged. A space above the upper net material 51 in the main chamber 36 is a diffusion chamber 64. The diffusion chamber 64 temporarily diffuses the vaporized fuel introduced from the tubular portion 46a to the upper portion of the main chamber 36 in the horizontal direction before being adsorbed by the main activated carbon 55 for the purpose of uniformly adsorbing the vaporized fuel to the main activated carbon 55. It is a space for making it happen.

Further, from the upper surface of the storage container 43, the tubular portion 43 for communicating the diffusion chamber 64 with the inside of the storage container 43.
a is protruding. In the storage container 43, the tubular portion 43a
And a spherical check valve 65 with a diameter slightly larger than the lower end opening of
Check valve 6 upward in the direction of closing the lower end opening
5 and a coil spring 66 that constantly biases 5 are housed.

The tubular portion 43a, the check valve 65 and the coil spring 66 are for returning the evaporated fuel or the like in the housing 34 to the fuel tank 23 when the temperature in the fuel tank 23 is lowered. More specifically, when the operation of the engine 1 is stopped or the temperature of the outside air decreases, the temperature inside the fuel tank 23 also decreases. Along with this, the volume of the evaporated fuel contracts, and the pressure of the evaporated fuel (gas) becomes lower than the atmospheric pressure. Due to this pressure difference, the check valve 65 is lowered against the biasing force of the coil spring 66, and the lower end opening of the tubular portion 43a is opened. By this opening, the evaporated fuel and the liquefied fuel in the storage container 43 are
It is returned (back-purged) to the fuel tank 23 via the first passage 30. The processing device 29 is configured as described above.

As shown in FIG. 1, the following sensors are provided in each part of the engine 1. A throttle sensor 67 for detecting the rotation angle (throttle opening TA) of the throttle valve 17 is attached to the throttle body 14. The cylinder block 1a has an engine 1
A water temperature sensor 68 for detecting the temperature of the cooling water (cooling water temperature THW) is attached.

An oxygen sensor 69 for detecting the oxygen concentration in the exhaust gas is attached to the exhaust passage 8. The oxygen sensor 69 is formed by coating a zirconia element with platinum and outputs a voltage (output voltage V) according to the concentration of oxygen as shown in FIG. The oxygen sensor 69 is
It has a characteristic that the output voltage V suddenly changes in the vicinity of the theoretical air-fuel ratio (14.5). Here, the air-fuel ratio is the weight ratio of air and fuel in the air-fuel mixture. The stoichiometric air-fuel ratio is the air-fuel ratio of the air-fuel mixture containing just enough oxygen to completely burn the fuel.

Besides, an air flow meter 70 for detecting the amount of air flowing in the intake passage 7 (intake air amount Q), an intake air temperature sensor 71 for detecting the temperature of the air flowing in the intake passage 7 (intake air temperature THA), and a crank. A rotation speed sensor 72 that detects the rotation speed of the shaft 5 (engine rotation speed NE) is provided.

The vehicle is equipped with an electronic control unit (Electronic Control Unit) for controlling the operations of the fuel injection valve 19 and the opening / closing valve 32 based on the detection signals of the sensors 67 to 72.
(nit, hereinafter, simply referred to as ECU) 73 is provided. The ECU 73 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RA
M), an external input circuit, an external output circuit, and the like. R
The OM stores a predetermined control program and initial data in advance. The CPU executes various arithmetic processes according to the control program and initial data. The RAM temporarily stores the calculation result by the CPU.

In order to control the operation of the fuel injection valve 19,
The ECU 73 calculates the amount of fuel injected from the fuel injection valve 19 (injection amount) according to the following equation (1). Here, the injection amount is determined by the time (injection time) during which the needle valve of the fuel injection valve 19 is open, that is, the energization time to the solenoid coil. Therefore, in equation (1),
The injection time TAU is calculated as the injection amount.

TAU = TP × f (1) In the equation (1), TP is a basic injection time for making the air-fuel ratio the stoichiometric air-fuel ratio, and is obtained by referring to the map stored in the ROM. The map defines the basic injection time with the engine speed NE and the intake air amount Q as parameters.

Further, f is a correction coefficient calculated by the sum or product of various coefficients. The various coefficients include, for example, intake air temperature, warm-up increase, post-start increase, air-fuel ratio feedback control, and the like.

The coefficient relating to the intake air temperature is for correcting the deviation of the air-fuel ratio caused by the difference in the intake air density due to the intake air temperature, and is obtained based on the intake air temperature THA. The coefficient relating to the warm-up increase amount is for increasing the basic injection time TP for the purpose of improving the driving performance during cold, and is obtained based on the intake air temperature THA. The coefficient related to the post-startup amount increase is for stabilizing the engine speed NE immediately after the start of the engine 1, and is obtained based on the cooling water temperature THW.

A feedback correction coefficient FAF is used as a coefficient relating to the feedback control of the air-fuel ratio.
The correction coefficient FAF is for correcting the basic injection time TP so that the air-fuel ratio of the air-fuel mixture converges to the stoichiometric air-fuel ratio. This correction coefficient FAF is obtained as follows.

As shown in FIG. 3, the output voltage V of the oxygen sensor 69 is compared with the reference value Vr for the stoichiometric air-fuel ratio, and if the output voltage V is higher than the reference value Vr, it is judged to be rich,
If it is lower than the reference value Vr, it is determined to be lean. In the case of rich, it is determined whether or not lean is determined to be rich by comparing with the previous detection result. When lean is reversed to rich, FAF-RS (RS is a skip amount) is set as a new correction coefficient FAF, and when lean is not reversed to rich, FAF-KI (KI is an integral amount, RS ≧ KI) is newly updated. The correction coefficient FAF is used.

Further, when the air-fuel ratio based on the signal from the oxygen sensor 69 is lean, it is compared with the previous detection result and it is judged whether or not the state is changed from rich to lean. When reversing from rich to lean, FAF + RS becomes a new correction factor F
In addition to AF, if there is no inversion from rich to lean, FAF + KI is set as a new correction coefficient FAF. Therefore,
When the air-fuel ratio is reversed between rich and lean, the correction coefficient FAF changes (skips) stepwise, and when the air-fuel ratio is rich or lean, the correction coefficient FAF gradually increases or decreases. As described above, the correction coefficient FAF for converging the air-fuel ratio to the stoichiometric air-fuel ratio is obtained based on the detection value of the oxygen sensor 69. The ECU 73 multiplies the basic injection time TP by this correction coefficient FAF.

The air-fuel ratio feedback control using the correction coefficient FAF is performed when the following stop condition is not satisfied. As the stop condition, for example, the engine 1
Is started, the amount of injected fuel is being increased after the start, the cooling water temperature THW is lower than a predetermined value, the vehicle is running at a high load, the fuel is cut, etc. .

Further, when the air-fuel ratio is controlled to the stoichiometric air-fuel ratio, the correction coefficient FAF fluctuates around "1.0". When the ECU 73 calculates the injection time TAU as described above, it outputs a drive signal corresponding to the calculated value to the fuel injection valve 19 via the external output circuit. In response to this signal,
The energization time to the solenoid coil of the fuel injection valve 19 is controlled, the time when the needle valve is open is adjusted, and a predetermined amount of fuel is injected from the injection valve 19.

Further, the ECU 73 controls the opening / closing valve 32 by the opening / closing valve 32 in order to control the operation of the opening / closing valve 32.
It is determined whether or not the condition for releasing 1 (purge condition) is satisfied. Examples of the purging condition include that feedback control of the air-fuel ratio is being performed and the cooling water temperature THW is equal to or higher than a predetermined value. The ECU 73 outputs a signal for opening the open / close valve 32 when the purge condition is satisfied. Further, the ECU 73 outputs a signal for closing the open / close valve 32 when the purge condition is not satisfied.

Next, the operation and effect of the processing device 29 when the opening / closing valve 32 is drive-controlled by the ECU 73 as described above will be described. FIG. 2 shows a state of the processing device 29 when the ECU 73 is outputting a signal for closing the opening / closing valve 32. The evaporated fuel generated in the fuel tank 23 passes through the first passage 30, the guide pipe 42, the storage container 43, and the guide pipe 44 in this order, and reaches the space below the diaphragm 47 of the valve case 46. At this time, if the force for pushing up the valve body 48 of the evaporated fuel is smaller than the biasing force of the coil spring 49, the tubular body 46a is closed by the valve body 48. Therefore, the evaporated fuel diffusion chamber 6
4 is cut off, and the pressure of the evaporated fuel in the storage container 43 and the like gradually increases.

Due to the rise in pressure, the valve element 48 for evaporated fuel
When the force for pushing up overcomes the biasing force of the coil spring 49 (the pressure of the evaporated fuel becomes higher than a predetermined value),
The valve body 48 rises and the tubular portion 46a is opened. With this opening, the vaporized fuel that has been blocked until then passes through the tubular portion 46a and flows into the diffusion chamber 64. On this occasion,
Since the second passage 31 is closed by the opening / closing valve 32, the evaporated fuel that has flowed into the diffusion chamber 64 is not blocked by the port 41.
It is diffused in the upper part of the main chamber 36 without being discharged.
The diffused fuel vapor passes through the upper net material 51 and flows downward. The flow of the evaporated fuel is changed by the fins 58 arranged around the storage container 43. As a result, the evaporated fuel flows obliquely downward and outward while following the fins 58 as shown by the arrows in FIG.

The evaporated fuel is adsorbed by the main activated carbon 55 in the main chamber 36 in the process of flowing as described above, and changes from vapor (gas) to liquid while generating heat. Part of the generated heat is transferred to the wall surface of the storage container 43. Similarly, a part of the heat is transferred to the wall surface of the housing 34 and radiated to the outside air from here.

At this time, since the evaporated fuel flows along the fins 58, the main activated carbon 5 near the wall surface of the storage container 43
The amount of adsorption in the vicinity of the wall surface of the housing 34 is larger than the amount of adsorption by 5. Therefore, the amount of heat generated near the wall surface of the housing 34 is larger than the amount of heat generated due to adsorption near the wall surface of the storage container 43. For this reason, most of the heat generated by adsorption is radiated to the outside air from the wall surface of the housing 34, and the temperature rise of the storage container 43 due to heat generation during adsorption is suppressed. Therefore, the fuel liquefied in the storage container 43 is unlikely to be affected by the heat generated by the adsorption and is unlikely to be gas again. The fuel remains liquid.

Next, FIG. 4 shows the processing unit 29 when the ECU 73 outputs a signal for opening the on-off valve 32.
Shows the state of. Even in this state, as in the case of FIG. 2, the evaporated fuel generated in the fuel tank 23 has the first passage 30,
It flows into the space below the diaphragm 47 of the guide pipe 42, the storage container 43, the guide pipe 44, and the valve case 46.

Further, the negative pressure generated in the intake passage 7 downstream of the throttle valve 17 acts on the main chamber 36 and the auxiliary chamber 37 via the opening / closing valve 32, the second passage 31 and the port 41. Due to this negative pressure, the air outside the housing 34 is released into the atmosphere port 3
9 is sucked into the housing 34. This air descends in the sub chamber 37, passes through the through hole 38, and rises in the main chamber 36. When the air passes through the sub chamber 37 and the main chamber 36,
The fuel adsorbed on the sub activated carbon 56 and the main activated carbon 55 is desorbed. The air-fuel mixture consisting of air rising in the main chamber 36 and fuel desorbed by the air passes through the diffusion chamber 64, the port 41, the second passage 31, and the intake passage 7 in this order, and the combustion chamber 6 of the engine 1. Burned in.

On the other hand, when desorbing the fuel, activated carbon 5
The fuel adsorbed by 5, 56 changes (vaporizes) from liquid to gas while absorbing heat. Therefore, the air near the vaporized fuel is cooled. A part of the cooled air-fuel mixture hits the storage container 43 and cools the evaporated fuel in the storage container 43. The cooled evaporated fuel becomes a liquid and is stored in the storage container 43.

In particular, in this embodiment, when the air-fuel mixture rises in the main chamber 36, its flow is changed by the fins 58 around the storage container 43. The air-fuel mixture obliquely flows inward while following the fins 58 as shown by arrows in FIG. Therefore, the air-fuel mixture cooled by the vaporization of the adsorbed fuel flows along the fins 58 toward the storage container 43. Most of the cooled air-fuel mixture that has risen in the main chamber 36 hits the storage container 43 and promotes the liquefaction of the evaporated fuel in the storage container 43.

As described above, in this embodiment, the main activated carbon 55
Also, before adsorbing the evaporated fuel to the sub activated carbon 56, a part of the evaporated fuel is liquefied in the storage container 43. Therefore, the load on both activated carbons 55 and 56 is reduced by the amount of liquefaction. As a result, even if a large amount of evaporated fuel flows into the processing device 29, the evaporated fuel can be prevented from being released to the atmosphere. Further, since the amount of fuel that finally reaches the combustion chamber 6 of the engine 1 from the second passage 31 is reduced by the amount of liquefaction, the disturbance of the air-fuel ratio due to the fuel can be reduced.

In this embodiment, the storage container 43 is embedded in the central portion of the main chamber 36 filled with the main activated carbon 55. A part of the evaporated fuel is liquefied by utilizing a phenomenon that the ambient heat is taken when the fuel adsorbed on the main activated carbon 55 is vaporized. For this reason, unlike the prior art in which the cooling water is used to liquefy the evaporated fuel, in this embodiment, the mechanism for liquefying the evaporated fuel can have an extremely simple structure. Since the evaporated fuel is cooled by utilizing the endothermic action when the fuel is desorbed from the activated carbon 55, 56,
It does not impair the cooling energy of the air conditioner.

Further, a large number of fins 58 for changing the flow of the air-fuel mixture are arranged around the storage container 43 so that the cooled air-fuel mixture concentrates and hits the storage container 43. Therefore, the evaporated fuel in the storage container 43 can be efficiently cooled and liquefied. Accordingly, the capacity of the housing 34 can be reduced as compared with the case where the fin 58 is not provided.

Further, in this embodiment, the net materials 62 and 63 are arranged above and below the storage container 43, and the space 5 without the main activated carbon 55 is provided.
9 and 61 are formed. For this reason, even if a large external force such that the housing 34 is deformed due to a collision or the like is applied, both the spaces 59 and 61 function as a moving place of the main activated carbon 55. That is, the shocks can be absorbed in the spaces 59 and 61, the storage container 43 can be prevented from being deformed or cracked by the shock, and the liquefied fuel can be prevented from leaking out.

The air flow in both the spaces 59 and 61 is originally poorer than in other places, and the fuel is not easily desorbed from the main activated carbon 55. Therefore, these spaces 59,
Although the main activated carbon 55 is not filled in 61, the adsorbed amount and the desorbed amount of fuel are almost the same as the case where the main activated carbon 55 is also filled in the spaces 59 and 61. Therefore, the main activated carbon 55 can be used without impairing the adsorption and desorption performances.
The usage amount of can be reduced.

When the engine is stopped, the liquefied fuel is
As the tank cools, it is returned to the fuel tank 23 through the first passage 30. Therefore, the present embodiment has an advantage that the fuel liquefied by returning to the fuel tank 23 can be used again as fuel. (Second Embodiment) Next, a second embodiment of the third invention will be described with reference to FIGS.

In the second embodiment, the opening / closing valve 32 is opened after a large amount of evaporated fuel is adsorbed on the activated carbons 55 and 56, so that the adsorbed fuel is desorbed from the activated carbons 55 and 56 all at once, and the storage container 4 is opened.
The third embodiment is greatly different from the first embodiment in that the evaporated fuel is cooled and liquefied in the chamber 3 more efficiently. Further, in the second embodiment, the oxygen sensor 69 and the water temperature sensor 6
8 constitutes an operating state detecting means for detecting the operating state of the engine 1. The engine 1,
Since the configuration of the processing device 29 and the like is similar to that of the first embodiment,
The description is omitted here.

FIG. 5 shows an opening / closing valve control routine executed by the ECU 73. This routine is started when the ignition switch is turned on for starting the engine 1, and thereafter executed every time a predetermined time has come. FIG. 6 shows the correspondence between the feedback correction coefficient FAF and the operating state of the on-off valve 32.

First, the EC at the timing t1 in FIG.
The processing of U73 will be described. The ECU 73 determines in step 101 whether a predetermined purge condition is satisfied. This condition is the same as the purge condition in the first embodiment (the feedback control of the air-fuel ratio is being performed and the cooling water temperature THW is equal to or higher than a predetermined value). If the purging conditions are not satisfied, the routine proceeds to step 102, where a signal for closing the on-off valve 32 is output,
This routine is once ended. This process is repeatedly executed until the purge condition is satisfied.

Therefore, in the processing device 29, since the second passage 31 is closed, the evaporated fuel generated in the fuel tank 23 is adsorbed by the main activated carbon 55 and the second
Fuel does not flow from the passage 31 of the engine 1 to the engine 1. Further, in the engine 1, the feedback correction coefficient FAF fluctuates around "1.0" due to the feedback control of the air-fuel ratio. When the purge condition in step 101 is satisfied at timing t2 in FIG. 6, the ECU 73 proceeds to step 103 and determines whether the condition is the first condition after engine start. When the first purge condition is satisfied, the ECU 73 proceeds to step 104 and outputs a signal for opening the open / close valve 32.

By this valve opening, the fuel adsorbed on the activated carbons 55, 56 is desorbed and taken into the combustion chamber 6 of the engine 1 through the second passage 31 and the intake passage 7. Due to this intake, the air-fuel ratio that has been controlled to near the theoretical air-fuel ratio becomes rich. Therefore, the feedback correction coefficient FAF is reduced in order to reduce the amount of injected fuel so that the air-fuel ratio approaches the stoichiometric air-fuel ratio.

Subsequently, in step 105, it is determined whether or not a predetermined time T1 set in advance has elapsed since the output of the signal for opening the open / close valve 32 was started. Immediately after the start of signal output and when the predetermined time T1 has not elapsed, this routine is temporarily terminated.
The processes of steps 101, 103, 104, and 105 are repeated until the determination condition of step 105 is satisfied.

When the determination condition of step 105 is satisfied at the timing t3 of FIG. 6, the process proceeds to step 106, and the deviation amount ΔFAF of the air-fuel ratio is calculated. This amount is equal to the feedback correction coefficient FAF and a predetermined value (for example, “1.
0 "). The deviation amount ΔFAF varies depending on the concentration of the evaporated fuel taken into the combustion chamber 6 from the second passage 31 during the period from timing t2 to t3. This amount corresponds to the amount of fuel adsorbed on the activated carbon 55, 56 before the timing t2 or the concentration (pressure) of the fuel evaporated from the fuel tank 23. That is, the greater the amount of fuel adsorbed on the activated carbon 55, 56 or the concentration of evaporated fuel in the fuel tank 23, the greater the concentration of fuel taken into the combustion chamber 6.

Next, at step 107, the valve closing time T2 corresponding to the deviation amount ΔFAF is calculated. Specifically, as shown in FIG. 7, the ROM of the ECU 73 stores a map in which the relationship between the air-fuel ratio deviation amount ΔFAF and the valve closing time T2 of the opening / closing valve 32 is predetermined. In this map, in a region where the deviation amount ΔFAF is smaller than the predetermined value a, the valve closing time T2 is set to increase as the deviation amount ΔFAF decreases. In addition, the deviation amount ΔF
The valve closing time T2 is set to a constant value in a region where AF is equal to or larger than the predetermined value a. The ECU 73 uses the map to open the valve closing time T corresponding to the deviation amount ΔFAF in step 106.
Calculate 2 and store the value.

Then, in step 102, a signal for closing the on-off valve 32 is output, and this routine is once ended. In the control cycle next to the timing t3 in FIG. 6, the determination condition of step 103 is not satisfied,
The process proceeds to step 108, and it is determined whether the valve closing time T2 has elapsed from the end of the first purge (when the second passage 31 is closed at the timing t3). Immediately after the timing t3 and the valve closing time T2 has not elapsed,
The process of step 102 is executed. That is, the on-off valve 3
The signal for continuing to close 2 is continuously output.

Therefore, in the processing device 29, since the second passage 31 which has been open up to that time is closed, the evaporated fuel generated in the fuel tank 23 becomes the main activated carbon 5
5, the fuel does not flow from the second passage 31 to the engine 1. Further, in the engine 1, the feedback correction coefficient FAF gradually increases due to the execution of the air-fuel ratio feedback control.

At the timing t4 when the valve closing time T2 has passed from the timing t3, the ECU 73 executes the step 1
After each processing of 01 and 103 is performed, it is determined that the determination condition of step 108 is satisfied, and the process proceeds to step 109. In step 109, a signal for opening the open / close valve 32 is output, and this routine is once ended.

Due to this opening, until then, activated carbon 55,5
The fuel adsorbed on 6 is desorbed all at once, and changes from liquid to gas while removing heat from the surroundings. Also, the storage container 4
The fuel vapor concentration in 3 is high. Therefore, the evaporated fuel in the housing 34 is efficiently cooled and liquefied.

The evaporated fuel concentration detecting means is constituted by the ECU 73 and the processing of step 106 in the opening / closing valve control routine. In addition, the ECU 73 and steps 101, 103 to 105, 1 in the on-off valve control routine.
The first control means is constituted by the respective processes of 07, 108, and 109.

As described above, in this embodiment, after the engine 1 is started and when the first purge condition is satisfied, the opening / closing valve 32 is opened for the predetermined time T1 to open the second passage 31.
To release. By this opening, activated carbon 5
The fuel adsorbed by 5, 56 is desorbed, and the air-fuel ratio deviation amount ΔFAF is obtained. This deviation amount ΔFAF is the second
It is estimated as the concentration of the evaporated fuel passing through the passage 31. That is, the smaller the deviation amount ΔFAF, the smaller the evaporated fuel concentration.

The smaller the fuel concentration, the longer the period from the end of the first purge to the start of the second purge (the valve closing time T2 of the on-off valve 32), and the more evaporated fuel the activated carbon 55 has. , 56. After the valve closing time T2 has elapsed, the on-off valve 32 is opened to desorb the adsorbed fuel at once, and the evaporated fuel in the storage container 43 is cooled and liquefied.

Therefore, the evaporated fuel can be efficiently cooled and liquefied as compared with the case where the on-off valve 32 is opened while the purge condition is satisfied. The cooling efficiency can be further improved as compared with the first embodiment. (Third Embodiment) Next, a third embodiment of the fourth invention will be described with reference to FIGS.

In the third embodiment, the first point is that the negative pressure air is stored when the engine 1 is operated and the stored negative pressure air is guided to the housing 34 when the engine 1 is stopped. And is largely different from the second embodiment. Further, in the third embodiment, the oxygen sensor 6 is used as in the second embodiment.
The water temperature sensor 68 and the water temperature sensor 68 constitute an operation state detecting means for detecting the operation state of the engine 1.

The reason why such a configuration is adopted is as follows. When the engine 1 is operating, heat is generated by the operation of the fuel pump 24. Further, high-temperature fuel is returned from the return pipe 26 into the fuel tank 23. as a result,
The liquid fuel 20 in the fuel tank 23 is heated, and the liquid fuel 20 is actively evaporated. Therefore, it is considered that the generated amount of evaporated fuel is the largest immediately after the operating engine 1 is stopped. At this time, the negative pressure air is supplied to the housing 3
4 to vaporize the fuel from activated carbon 55, 56,
The evaporated fuel in the storage container 43 should be able to be efficiently liquefied. However, when the engine 1 is stopped, no negative pressure is generated in the intake passage 7, so negative pressure air cannot be introduced into the housing 34 as it is. From this point of view, the configuration of this embodiment is adopted.

The same members as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. As shown in FIG. 8, a negative pressure air storage container 74 having a predetermined volume is provided in the second passage 31 closer to the housing 34 than the on-off valve 32. An electromagnetic auxiliary opening / closing valve 7 is provided in the second passage 31 on the housing 34 side of the container 74.
5 are provided. The auxiliary opening / closing valve 75, like the opening / closing valve 32, opens and closes according to an electric signal from the outside (ECU 73).

FIG. 9 shows a valve control routine executed by the ECU 73. This routine is executed at a predetermined timing. The ECU 73 determines in step 201 whether or not a predetermined purge condition is satisfied. This condition is the purge condition in the first embodiment (the feedback control of the air-fuel ratio is being performed, and the cooling water temperature THW is
Is greater than or equal to a predetermined value). If the purge condition is satisfied, the routine proceeds to step 202, where the on-off valve 32
Then, a signal for opening both the auxiliary opening / closing valve 75 and the auxiliary opening / closing valve 75 is output, and this routine is once ended. This process is repeatedly executed while the purge condition is satisfied.

By opening these valves, the intake passage 7 is communicated with the housing 34, and the fuel adsorbed on the activated carbons 55 and 56 is desorbed. The desorbed fuel is in the second passage 3
1 and the intake passage 7 to be taken into the combustion chamber 6 of the engine 1 and burned there.

When the purge condition is not satisfied, the routine proceeds to step 203 after the judgment processing of step 201, and the signal for closing the auxiliary opening / closing valve 75 is output. By the processing of step 203, the auxiliary opening / closing valve 75 is closed while the opening / closing valve 32 remains open. Therefore, in the housing 34, the evaporated fuel generated in the fuel tank 23 is adsorbed by the main activated carbon 55, and the fuel does not flow from the second passage 31 to the engine 1. Further, the negative pressure generated due to the operation of the engine 1 acts on the inside of the container 74 via the second passage 31.

Subsequently, in step 204, after the signal for closing the auxiliary opening / closing valve 75 is started,
It is determined whether or not a predetermined time T3 set in advance has elapsed. Immediately after the start of signal output and when the predetermined time T3 has not elapsed, in step 205, a signal for opening the open / close valve 32 is output.

In step 207, it is determined whether the engine 1 is operating. If it is operating, this routine is once ended. Until the determination condition of step 204 is satisfied, steps 201, 203, 20
Each processing of 4,205,207 is repeated. Therefore, the negative pressure air in the intake passage 7 is stored in the container 74 over the predetermined time T3.

When the determination condition of step 204 is satisfied,
In step 206, a signal for closing the open / close valve 32 is output. When the opening / closing valve 32 is closed according to the process of step 206, the container 74 is closed because the auxiliary opening / closing valve 75 is already closed.
Therefore, the negative pressure air that has been stored in the container 74 by that time is enclosed. This state is maintained unless the engine 1 is operating and the purging conditions are not satisfied.

When the engine 1 is stopped, it is determined that the determination condition of step 207 is no longer satisfied, and in step 208 a signal for opening the auxiliary opening / closing valve 75 is output. By opening the auxiliary opening / closing valve 75, the housing 34 and the container 74 are communicated with each other. The negative pressure air that has been enclosed in the container 74 until then is introduced into the housing 34, and the fuel adsorbed by the activated carbons 55 and 56 is desorbed. At the time of this desorption, the fuel adsorbed on the activated carbons 55, 56 changes from liquid to gas while absorbing the heat of the surroundings, and the air in the vicinity of the vaporized fuel is cooled. Therefore, the evaporated fuel in the housing 34 is cooled and liquefied. The desorbed and vaporized fuel is stored in the container 74.

The ECU 73 and the processing of steps 201 and 203 in the on-off valve control routine constitute the second control means, and similarly, the ECU 73 and the processing of steps 204, 205, 206, 207 and 208 form the third control means. Control means is configured.

As described above, in the third embodiment, when the operating condition of the engine 1 satisfies the purge condition, both the opening / closing valve 32 and the auxiliary opening / closing valve 75 are opened, and when the operating condition does not satisfy the purge condition, The auxiliary opening / closing valve 75 is closed while the opening / closing valve 32 is opened to store the negative pressure air in the intake passage 7 in the container 74. After the auxiliary opening / closing valve 75 is closed, the opening / closing valve 32 is closed when a predetermined time T3 has passed, and when the engine 1 is stopped thereafter, the auxiliary opening / closing valve 75 is opened with the opening / closing valve 32 closed. The negative pressure air in the container 74 is guided into the housing 34.

Therefore, the negative pressure air can be introduced into the housing 34 immediately after the engine 1 which is considered to generate a large amount of evaporated fuel is stopped. With this introduction, activated carbon 5
The fuel can be desorbed from 5, 56, and a large amount of the evaporated fuel in the storage container 43 can be efficiently cooled and liquefied.

The present invention can be embodied in another embodiment shown below. (1) The sub chamber 37 and the sub activated carbon 56 may be omitted. (2) The fins 58 may be curved and the number of the fins 58 used may be appropriately changed. Further, the fin 58 may be omitted.

(3) In each of the embodiments, the top and bottom surfaces of the storage container 43 are formed in a flat shape, but they may be formed in a conical shape or a hemispherical shape. By doing so, the flow of fuel near the top surface and bottom surface is improved. In this case, space 5 without activated carbon 55
You may omit 9,61.

Although the respective embodiments of the present invention have been described above, technical ideas other than the claims which can be understood from the respective embodiments will be described below together with their effects. (A) In the evaporative fuel treatment apparatus according to claim 1, the liquid fuel storage container has surfaces (top surface and bottom surface) substantially orthogonal to the flow direction of the fuel desorbed from the adsorbent and vaporized, and the surface The evaporative fuel processing system has a space not filled with activated carbon near the.

With this structure, even when a large external force is applied to the canister housing, the space prevents the force from reaching the liquid fuel storage container, and the liquid fuel stored in the storage container leaks out. Can be prevented.
Further, the amount of the adsorbent used can be reduced without impairing the adsorption performance and desorption performance of the evaporated fuel by the adsorbent.

In this specification, means and members relating to the constitution of the invention are defined as follows. The (a) adsorbent means a material that adsorbs and releases vaporized fuel, and includes monolith activated carbon and fibrous activated carbon in addition to the granular activated carbon described in the first to third embodiments.

[0109]

As described in detail above, in the first aspect of the invention, the liquid fuel storage container is embedded in the adsorbent, and the heat is absorbed when the fuel is desorbed from the adsorbent and vaporized. The evaporated fuel passing through is cooled and stored in a liquid state. Therefore, the evaporated fuel can be liquefied with a simple structure. Moreover, since cooling water such as an air conditioner is not used to liquefy the evaporated fuel,
The loss of cooling energy can be prevented.

According to the second aspect of the present invention, the flow changing member is provided inside the canister housing, and the flow direction of the fuel is changed so that the fuel desorbed from the adsorbent and vaporized flows toward the liquid fuel storage container. I have to. Therefore, in addition to the effect of the first aspect of the invention, the evaporated fuel can be efficiently cooled, and more evaporated fuel can be liquefied and stored in the liquid fuel storage container. Further, the canister housing can be downsized.

In the third aspect of the invention, when the operating condition of the internal combustion engine satisfies the predetermined condition, the smaller the concentration of the evaporated fuel passing through the second passage becomes after the opening / closing valve is opened for a certain period of time. The on-off valve is closed so that the closing time of the on-off valve becomes longer, and then the on-off valve is opened again. Therefore, in addition to the effect of the first or second invention, after adsorbing a large amount of evaporated fuel to the adsorbent, the on-off valve is opened and vaporized at once, and the evaporated fuel in the liquid fuel storage container is efficiently liquefied. Can be made.

In the fourth invention, in addition to the on-off valve, the negative pressure air storage container and the auxiliary on-off valve are provided in the second passage.
When the operating state of the internal combustion engine does not satisfy the predetermined condition, the auxiliary opening / closing valve is closed while the opening / closing valve is opened, and the negative pressure air in the intake passage is stored in the negative pressure air storage container.
After closing the auxiliary opening / closing valve, the opening / closing valve is closed when a preset time has elapsed, and then, when the internal combustion engine is stopped, the auxiliary opening / closing valve is opened with the opening / closing valve closed. There is.

Therefore, in addition to the effects of the first or second invention, immediately after the internal combustion engine, which is considered to generate a large amount of evaporated fuel, the negative pressure air in the negative pressure air storage container is introduced into the canister housing. Therefore, the fuel adsorbed on the adsorbent can be vaporized. Therefore, most of the evaporated fuel in the liquid fuel storage container can be cooled and efficiently liquefied.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an engine, an evaporated fuel processing apparatus, and the like in a first embodiment embodying the first and second inventions.

FIG. 2 is a schematic configuration diagram showing a state of an evaporated fuel processing device when a second passage is closed by an opening / closing valve in the first embodiment.

FIG. 3 is a timing chart showing the correspondence relationship between the output voltage of the oxygen sensor and the feedback correction coefficient in the first embodiment.

FIG. 4 is a schematic configuration diagram showing a state of an evaporated fuel processing device when a second passage is opened by an opening / closing valve in the first embodiment.

FIG. 5 shows a second embodiment embodying the third invention,
6 is a flowchart illustrating an on-off valve control routine executed by the ECU.

FIG. 6 is a timing chart showing the correspondence between the feedback correction coefficient and the operating state of the on-off valve in the second embodiment.

FIG. 7 is a characteristic diagram showing a map that predefines the relationship between the amount of deviation of the air-fuel ratio and the valve closing time in the second embodiment.

FIG. 8 is a schematic configuration diagram of an engine, an evaporated fuel processing device, and the like in a third embodiment embodying the fourth invention.

FIG. 9 is a flowchart illustrating a valve control routine executed by an ECU in the third embodiment.

[Explanation of symbols]

1 ... Engine as internal combustion engine, 7 ... Intake passage, 20 ...
Liquid fuel, 23 ... Fuel tank, 29 ... Evaporative fuel treatment device, 30 ... First passage, 31 ... Second passage, 32 ... Open / close valve, 34 ... Canister housing, 43 ... Liquid fuel storage container, 55 ... Adsorbent Activated carbon, which forms part of the ...
Sub-activated carbon forming a part of the adsorbent, 58 ... Fins as a flow changing member, 68 ... Water temperature sensor forming a part of operating state detecting means, 69 ... Oxygen sensor forming a part of operating state detecting means, 73 ... Evaporated fuel concentration detecting means, ECU constituting first control means, second control means and third control means, 74 ... Negative pressure air storage container, 75 ... Auxiliary on-off valve, T2 ... Valve closing time .

Claims (4)

[Claims] 1. A canister housing containing an adsorbent and a fuel tank are connected by a first passage, and
The canister housing and the intake passage of the internal combustion engine
And an opening / closing valve is provided in the middle of the second passage. When the opening / closing valve is closed, the evaporated fuel generated from the liquid fuel in the fuel tank is adsorbed by the adsorbent, and the opening / closing valve is opened. When the valve is opened, the fuel adsorbed in the adsorbent is desorbed and released into the intake passage, and a liquid fuel storage container is embedded in the adsorbent in the canister housing. Then, when the evaporated fuel from the fuel tank passes through the same storage container, the endothermic action when the fuel is desorbed from the adsorbent and vaporized causes the evaporated fuel to cool and become a liquid state in the storage container. Evaporative fuel processing device that is designed to store in. 2. The inside of the canister housing includes:
The evaporative fuel treatment apparatus according to claim 1, further comprising a flow changing member that changes a flow direction of the fuel that is desorbed from the adsorbent and vaporized and flows toward the liquid fuel storage container. 3. An operating state detecting means for detecting an operating state of the internal combustion engine, an evaporated fuel concentration detecting means for detecting a concentration of evaporated fuel passing through the second passage, and an operating state by the operating state detecting means. Satisfies a predetermined condition, after the opening / closing valve is opened for a certain period of time, the opening / closing valve is opened so that the closing time of the opening / closing valve becomes longer as the fuel concentration by the evaporated fuel concentration detecting means becomes smaller. The evaporated fuel processing apparatus according to claim 1 or 2, further comprising: first control means for closing the valve and then opening the on-off valve again. 4. A negative pressure air storage container, which is provided closer to the canister housing than the on-off valve in the second passage and has a predetermined volume, and a negative pressure air storage container in the second passage. An auxiliary opening / closing valve provided on the side of the canister housing and opening and closing the second passage, an operating state detecting means for detecting an operating state of the internal combustion engine, and an operating state by the operating state detecting means are predetermined. When the condition is satisfied, both the opening / closing valve and the auxiliary opening / closing valve are opened, and when the operating state by the operating state detecting means does not satisfy the condition, the auxiliary opening / closing valve is closed while the opening / closing valve is opened. Second control means for storing negative pressure air in the intake passage in the negative pressure air storage container, and after a preset time elapses after the auxiliary control valve is closed by the second control means. When the internal combustion engine is stopped after closing the closing valve, the auxiliary opening / closing valve is opened with the opening / closing valve closed, and the negative pressure air in the negative pressure air storage container is introduced into the canister housing. The evaporative fuel treatment apparatus according to claim 1, further comprising a third control unit that guides the vaporized fuel.