JPH11200960A - Fuel vapor treatment device - Google Patents

Abstract

(57) Abstract: Provided is an evaporative fuel processing apparatus capable of achieving a function of efficiently processing fuel vapor in a wide operating region including an idle operation of an engine with a low cost and a simple configuration. A purge passage 23 extending from a canister 20 to an intake passage 13 bifurcates on the way, and an opening at one end is connected to an upstream side near a throttle valve 14 and an opening at another end is connected to the inside of the ISC valve 16. Have been. ISC
The valve 16 is a rotary on-off valve driven by the electromagnetic action of a solenoid, and the effective internal area of the bypass passage 15 of the intake air at the time of idling operation is obtained by rotating a valve body inside the valve 16 around a rotation axis. Is adjusted, and when the effective cross-sectional area has a predetermined area corresponding to the idling operation region when the air conditioner is operating, the flow of vapor from the purge passage 23 to the bypass passage 15 is allowed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention collects fuel vapor generated in a fuel tank in a canister without releasing it into the atmosphere, and purifies the collected fuel into an intake passage of an engine for processing. More particularly, the present invention relates to a fuel vapor processing apparatus that performs purging even when an engine is idle.

[0002]

2. Description of the Related Art As one of devices mounted on a vehicle or the like,
There is a fuel vapor treatment device. This device temporarily collects fuel vapor (hereinafter, referred to as vapor) generated in a fuel tank into a canister so as not to be released into the atmosphere, and purges the collected fuel vapor to an intake passage of an engine as necessary. It is for. The vapor purged into the intake passage is added to the original fuel supplied into the combustion chamber of the engine by the fuel injection device.

FIG. 4 shows an example of an engine system equipped with a conventional fuel vapor processing device. Gasoline engine 1
During normal operation of the engine system 100 composed mainly of the engine 12, the amount of intake air is adjusted by the opening of a throttle valve 114 provided in the middle of the intake passage 113. On the other hand, at the time of idling operation, suction is performed by opening an idle speed control valve (ISC valve) 116 provided in a bypass passage 115 having openings on the upstream and downstream sides of the throttle valve 114 and bypassing the intake passage 113. The air flow is adjusted.

The canister 120 collects vapor generated in the fuel tank 119 through a vapor passage 122 and then purges the purge passage into an intake passage 113 through a purge passage 123. A purge control valve 123a provided in the middle of the purge passage 123 is an electromagnetic valve whose opening can be adjusted steplessly, and controls the amount of vapor going from the canister 120 to the intake passage 113 by an electronic control unit (ECU). )
It is adjusted appropriately based on the control signal from 121.

Incidentally, the amount of vapor purged from the canister 120 into the intake passage 113 affects the air-fuel ratio related to the combustion of the engine 112. Therefore, normally, while the purge flow rate is adjusted by opening and closing the purge control valve 123a, the fuel injection amount is corrected by estimating, for example, the influence of the purge by feedback from the deviation amount of the air-fuel ratio. In such a case, the air-fuel ratio is more likely to be disturbed by the influence of the purge as the engine load represented by the fuel injection amount, the engine speed, and the like is smaller. Therefore, in order to execute purging under such conditions, precise control of the purge flow rate is required.

On the other hand, the temporary storage capacity of the vapor by the canister 120 is limited, and in order to constantly maintain this storage capacity, the vapor once collected in the canister 120 is purged into the intake passage as soon as possible. Better. From such a viewpoint, it is more advantageous to cause the canister 120 to perform the purge not only during the normal operation but also during the idle operation. For example, when the idle operation is performed in the air conditioner operating state, the outside air temperature is high, and vapor is easily generated from the fuel tank 119. Further, in such a situation, the fuel injection amount is sufficiently large, and the conditions for performing the purge are satisfied (the air-fuel ratio is relatively unlikely to be disturbed even if the purge is performed). desirable.

[0007]

As described above, the essential function of the fuel vapor processing apparatus, that is, the function of preventing the vapor generated in the fuel tank from being released into the atmosphere, is achieved, and the operating state of the engine is stabilized. In order to maintain
Purge control valve (opening / closing control valve) capable of precise opening adjustment
Obviously, the installation of is essential. However,
Incorporating an on-off control valve that satisfies such conditions into the engine system only for the purging process complicates the entire system and is disadvantageous in terms of cost.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a low-cost and simple function of efficiently processing fuel vapor in a wide operating region including an idle operation of an engine. It is an object of the present invention to provide an evaporative fuel treatment apparatus which can be achieved by the above configuration.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, an invention according to claim 1 is characterized in that a bypass passage for bypassing an upstream side and a downstream side of a throttle valve disposed in an intake pipe, and an idle operation. An idle speed control valve that varies the effective cross-sectional area of the bypass passage in order to adjust the amount of intake air at the time, and once collecting fuel vapor generated in the fuel tank by a canister. A fuel vapor processing apparatus for purging the fuel vapor into the intake pipe through a purge passage, wherein the idle speed control valve has first and second openings serving as an inlet and an outlet of the intake air, respectively. And a third opening serving as an inlet for the fuel vapor, wherein at least one of the first and second openings is provided based on the movement of the valve body. By changing the effective cross-sectional area of the bypass passage by changing the cross-sectional area, the third opening and the second opening are communicated with each other, and the purge passage has an opening to the intake pipe. The gist of the invention is that at least a part of the end is connected to the third opening of the idle speed control valve.

According to this configuration, even when the engine is in an idling operation state, purging can be appropriately performed under an operation condition in which a large amount of fuel vapor is generated. Further, simplification of the entire apparatus and reduction of the manufacturing cost can be achieved.

According to a second aspect of the present invention, in the fuel vapor processing apparatus according to the first aspect, the purge passage is branched into two passages on the intake pipe side, one of which is the throttle valve of the intake pipe. The gist is that it is connected upstream and the other is connected to the third opening of the idle speed control valve.

According to this configuration, during normal operation of the engine,
The fuel vapor is directly purged into the intake pipe, and during idle operation, the purge is performed under precise flow control via the idle speed control valve. Purge control can be performed.

[0013] The invention according to claim 3 is the invention according to claim 1 or 2.
In the fuel vapor processing apparatus described above, the gist of the present invention is that the idle speed control valve selectively connects the third opening and the second opening at a predetermined moving position of the valve body.

According to this configuration, it is possible to execute a purge by selecting a specific operation state such as an air conditioner operation in which fuel vapor is likely to be generated during the idle operation. As a result, the fineness of the purge control can be further improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a fuel vapor processing apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an engine system of an automobile provided with a fuel vapor processing apparatus according to the present embodiment. The system 10 includes a gasoline engine 12 having a combustion chamber 11, an intake passage 13 for supplying a mixture of fuel (including vapor (fuel vapor)) and air to the combustion chamber 11, and a middle of the intake passage 13. A throttle valve 14 that adjusts a flow rate of intake air flowing through the passage based on operation of an accelerator pedal (not shown), and a throttle sensor 1 that detects an opening degree TA of the throttle valve 14.
4a, a bypass passage 15 of the intake passage 13 having openings on the upstream and downstream sides of the throttle valve 14, and an ISC valve provided in the bypass passage 15 for adjusting a flow rate of a small amount of intake air supplied during idling operation or the like. (Idle speed control valve) 16, an exhaust passage 17 for discharging exhaust gas generated by combustion of the air-fuel mixture, a fuel injection valve 18 for injecting fuel into an intake passage 13 near the combustion chamber 11, and a fuel injection valve 18. A fuel tank 19 for storing fuel to be supplied, a canister 20 for once collecting vapor (fuel vapor) generated in the fuel tank 19, and ignition at a predetermined ignition timing in conjunction with rotation of a camshaft (not shown). Distributor 11 for applying voltage to plug 11a
b, a rotational speed sensor 11c provided in the distributor 11b and detecting the rotational speed NE of the engine. And an ECU (electronic control device) 2
1 gives a control command to each part of the engine system 10 based on various operating state parameters TA, NE, and the like.

The canister 20 is connected to a vapor passage 22 for introducing vapor from the fuel tank 19 and a purge passage 23 for purging collected vapor into the intake passage 13. The purge passage 23 bifurcates on the way from the canister 20 to the intake passage 13, and has one end connected to the intake passage 13 near the upstream side of the throttle valve 14, and the other end of the branched purge passage 23. Are connected to the ISC valve 16. In the purge passage 23, check valves 24 and 25 are respectively provided in the middle of the two branched passages, and regulate the backflow of the vapor to the canister 20 side.

FIGS. 2A to 2D are schematic sectional views of the ISC valve 16 according to the present embodiment. This ISC
The valve 16 is a rotary valve driven by an electromagnetic action of a solenoid, and is provided in a housing 34 which communicates with an intake air inlet 31, an outlet 32, and one end opening (a vapor inlet) 33 of the purge passage 23. And a rotatable valve body 35. Based on a command signal from the ECU 21, a valve 35 driven by a predetermined amount of current flowing through a solenoid (not shown) rotates relative to the housing 34 about a rotation shaft 36, and the opening of the intake air inlet 31 is opened. Change the area. In this way, the flow rate of the intake air flowing through the bypass passage 15 is adjusted steplessly.
The slit 37 formed in the valve body 35 communicates with the one end opening 33 of the purge passage 23 and flows in from the purge passage 23 only when the rotation phase of the valve body 35 with respect to the housing 34 is at a predetermined phase. The vapor is opened into the ISC valve 16.

Next, the operation of the fuel vapor processing apparatus configured as described above will be described with reference to FIGS. When the engine system (see FIG. 1) 10 performs the normal operation, the flow rate of the intake air supplied to the combustion chamber 11 is controlled by opening the throttle valve 14 that operates according to the operation of an accelerator pedal (not shown). Adjusted by degree. At this time, the purge is performed from the canister 20 through the path A of the purge passage 23, and the vapor is directly discharged from the opening of the passage A to the intake passage 13.

On the other hand, when the engine system 10 performs the idling operation, the throttle valve 14 is fully closed, and all the supply of the intake air to the engine 12 is performed through the bypass passage 15. That is, ISC
The intake air flow rate is adjusted by adjusting the opening of the valve 16.

At this time, as the target intake air flow rate is higher, the ECU 21 rotates the valve element 35 in the ISC valve 16 to sequentially activate the bypass passage 15 as shown in FIGS. 2 (a) to 2 (d). Enlarge the cross-sectional area. In particular, IS
When the relative rotation phase of the valve body 35 with respect to the housing of the C valve 16 is in the phase shown in FIG. 2C, the path B of the purge passage 23 and the space in the ISC valve 16 communicate with each other. The air flows through the bypass passage 15 toward the downstream side of the intake passage 13 through the passage 16. The two check valves 24 and 25 provided in the middle of the branched purge passage 23 are connected to the vapor canister 20.
In order to restrict the flow to the side, the vapor or the intake air does not flow backward toward the canister 20 regardless of whether the engine 12 is in the idle operation state or the normal operation state.

On the other hand, FIGS. 3A and 3B show the purge of vapor (via the path B) corresponding to the case where the horizontal axis of the ISC valve 16 is set to the horizontal axis of the same scale. The relationship between the flow rate and the intake air flow rate is shown. However, the change modes of the purge flow rate and the intake air flow rate are both on the assumption that the throttle valve 14 is in the fully closed state. Points (a) to (d) indicated by arrows in FIG. 3 (B) correspond to FIG. 2 (a) to FIG.
This corresponds to the operating position of the valve body 35 of the ISC valve 16 shown in (d).

Here, as shown in FIG. 3B, the idling state of the engine 12 can be divided into, for example, three operating regions depending on the opening degree of the ISC valve 16 at that time. That is, the engine speed is the lowest and the ISC
A region (i) corresponding to a normal idle operation in which the amount of intake air supplied through the valve 16 is small, and a region (ii) in which the engine speed and the amount of intake air are slightly higher, such as an idle operation when the air conditioner is operating. And a so-called idling operation at the time of cold start or start-up such as a warm-up operation of the engine 12, and a region (iii) in which the engine speed and the intake air amount are set higher. . Of these three areas, the idle operation area (i
In i), the outside air temperature is high, and the amount of fuel vapor generated in the fuel tank 19 is the largest. Therefore, in the ISC valve 16 of the present embodiment, the housing inner wall 34a
A slit 37 is provided in a part of the valve body 35 for adjusting the effective cross-sectional area of the bypass passage 15 by sliding with the housing 34, so that the rotation phase of the valve body 35 with respect to the housing 34 becomes a predetermined phase corresponding to this region (ii). In some cases, the slit 37 overlaps with the opening from the purge passage 23 so that the purge passage 23 and the inside of the housing 34 communicate with each other (see FIG. 2C). As a result, as shown in FIG. 3A, when the valve opening of the ISC valve 16 is in the same region (ii), purging is selectively performed.

As described above, in the fuel vapor processing apparatus according to the present embodiment, the purge passage 23 is branched into two branches toward the intake passage 13, and one end thereof is connected to the intake passage 13 upstream of the throttle valve 14. At the same time, the other end is connected to an ISC valve 16 in the middle of the bypass passage 15. Then, the slit 3 is formed in the valve body 35 of the ISC valve 16.
7, the purge passage 23 is opened to the bypass passage 15 only when the effective sectional area of the bypass passage 15 has a predetermined sectional area corresponding to the region (ii).
The ISC valve 16 also functions as a purge control valve conventionally provided independently in the middle of the purge passage. For this reason, even when the engine 12 is in the idling operation state, it is possible not only to perform the purge as appropriate under the operating conditions where the amount of generated fuel vapor is large, but also to simplify the entire apparatus and reduce the production cost. At the same time, it can be planned.

As described in detail above, according to the present embodiment, the following effects can be obtained. -Even when the engine 12 is in the idle state, the purge can be selectively executed in the operation region where the amount of the evaporated fuel is large. -By using the ISC valve 16 also as a purge control valve, simplification of the apparatus and reduction of production cost can be achieved.

In this embodiment, the valve body 35 in the ISC valve 16 has only one slit, and the purge is performed only when the engine 12 is in an idle state when the air conditioner is operating. However, if, for example, a plurality of slits having different opening widths are provided, a plurality of slits in the idle operation region divided by the size of the effective cross-sectional area of the bypass passage 15 may be provided. It can also be configured to allow for a fixed amount of purge.

In the branched purge passage 23,
In the middle of the branch passage directly connected to the intake passage 13, for example, a diaphragm type opening / closing control valve may be provided. With this configuration, even when the engine 12 is in a normal operating state, the purge flow rate can be adjusted stepwise according to the opening degree of the throttle valve 14 and the like.

In this embodiment, the ISC valve 16
The adjustment of the effective area of the bypass passage 15 by the
The intake air introduction part 31 of the C valve 16 was adjusted by opening and closing it with a valve body 35.
5 may be used to open and close. Further, a configuration may be adopted in which both the introduction part 31 and the derivation part 32 are opened and closed by the valve body 35 to perform adjustment.

In the present embodiment, a rotary valve is used as the ISC valve 16. However, the ISC valve 16 may be, for example, an effective sectional area of the bypass passage 15 based on a slide of a long valve. It is also possible to use a long valve for adjusting the pressure and controlling the purge.

While the embodiment of the present invention has been described above, technical ideas other than the claims that can be grasped from the embodiment will be described below together with their effects.

(1) A first opening serving as an introduction portion of the first fluid, a second opening serving as an outlet of the first fluid,
A housing having a third opening serving as an inlet for the second fluid, and at least one of the first and second openings being housed in the housing and sliding along an inner wall of the housing. A flow control valve, wherein one of the effective cross-sectional areas is variable, and a valve body that allows the third opening and the second opening to communicate with each other is provided.

According to the above configuration, the fluid adjusting function of mixing the second fluid appropriately according to the flow rate of the first fluid while adjusting the flow of the first fluid can be achieved with a simple structure and It can be achieved accurately.

(2) The first and second openings are connected to a bypass passage that bypasses an upstream side and a downstream side of a throttle valve disposed in an intake pipe of the engine. The flow control valve according to (1), which is connected to a purge passage derived from a canister for temporarily collecting fuel vapor generated in a fuel tank of the engine.

(3) The flow control valve according to (1) or (2), wherein the valve body communicates the third opening with the second opening at a predetermined sliding position. According to the configuration of (2) or (3), a function of adjusting the intake air amount and the purge flow rate by adjusting the flow rate of the intake air flowing through the bypass passage and appropriately mixing the vapor flowing from the canister according to the flow rate. Can be easily and accurately achieved.

[0035]

According to the first aspect of the present invention, even when the engine is in an idling operation state, purging can be appropriately performed under an operation condition in which a large amount of fuel vapor is generated. Further, simplification of the entire apparatus and reduction of the manufacturing cost can be achieved.

According to the second aspect of the present invention, during normal operation of the engine, the fuel vapor is directly purged into the intake pipe, and during idle operation, the purge is performed under precise flow control via the idle speed control valve. By doing so, the purge control can be performed with necessary and sufficient accuracy in each of the normal operation and the idle operation.

According to the third aspect of the present invention, it is possible to execute a purge by selecting a specific operation state such as an air conditioner operation in which fuel vapor is easily generated, even during an idle operation. become. As a result, the fineness of the purge control can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an engine system to which a fuel vapor processing device according to the present invention is applied.

FIG. 2 is a schematic cross-sectional view showing an ISC valve of the embodiment and an operation mode thereof.

FIG. 3 is a diagram showing a variation of a purge flow rate and an intake air amount with respect to a valve opening degree of the ISC valve according to the embodiment.

FIG. 4 is a schematic configuration diagram showing an example of an engine system equipped with a conventional fuel vapor processing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Engine system, 11 ... Combustion chamber, 11a ... Spark plug, 11b ... Distributor, 11c ... Rotation speed sensor, 12 ... Engine, 13 ... Intake passage, 14 ... Throttle valve, 15 ... Bypass passage, 16 ... ISC
(Idle speed control) Valve, 17: exhaust passage, 18: fuel injection valve, 19: fuel tank, 20: canister, 21: ECU (electronic control device), 22: vapor passage, 23: purge passage, 24, 25 ... Check valve, 31: intake air introduction part, 32: intake air outlet part, 33: opening of purge passage, 34: housing, 3
5: valve element, 36: rotating shaft, 37: slit.

Claims (3)

[Claims] 1. A bypass passage for bypassing an upstream side and a downstream side of a throttle valve disposed in an intake pipe, and an idle passage for varying an effective sectional area of the bypass passage so as to adjust an intake air amount during idling operation. A fuel control apparatus for an engine having a speed control valve, wherein the fuel vapor generated in the fuel tank is once collected by a canister and the fuel vapor is purged into the intake pipe through a purge passage. The idle speed control valve includes first and second openings serving as an inlet and an outlet for the intake air, and a third opening serving as an inlet for the fuel vapor. Changing the effective cross-sectional area of the bypass passage by changing the effective cross-sectional area of at least one of the first and second openings based on the movement of the body; In addition, the third opening and the second opening are communicated with each other, and at least a part of an opening end of the purge passage to the intake pipe is formed by the third opening of the idle speed control valve. A fuel vapor processing device connected to the opening. 2. The fuel vapor processing device according to claim 1, wherein the purge passage is branched into two passages on the intake pipe side, one of which is connected to the intake pipe upstream of the throttle valve, and the other. Is connected to the third opening of the idle speed control valve. 3. The fuel vapor according to claim 1, wherein the idle speed control valve selectively communicates the third opening and the second opening at a predetermined moving position of the valve body. Processing equipment.