JP2011144723A - Vaporized fuel processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vaporized fuel processing device that can stably maintain a sufficient negative pressure without causing a short of fuel supply to an internal combustion engine. <P>SOLUTION: The vaporized fuel processing device includes a fuel pump 11, a canister 10, a pressure regulator 13, an aspirator 12 for generating a negative pressure by utilizing a part of discharged fuel discharged from the fuel pump 11, and the like, and the vaporized fuel processing device retrieves vaporized fuel by the negative pressure of the aspirator 12. The pressure regulator 13 and the aspirator 12 communicate with the fuel pump 11 via a relief passage 7 and a fuel introducing passage 6, respectively. Further, a fuel introducing valve 21 for increasing and decreasing a fuel amount introduced to the aspirator 12 while maintaining the amount and is provided to the fuel introducing passage 6. The fuel introducing valve 21 is an electromagnetic valve controlled to open and close by an EUC 25 and the fuel introducing amount is increased and decreased by a control of a duty ratio determined by dividing a valve opening time length by a total of a valve opening time length and a valve closing time length. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a fuel tank for storing fuel, a fuel pump for supplying fuel in the fuel tank to an internal combustion engine, a canister for adsorbing evaporated fuel (vapor) generated in the fuel tank, and evaporation from the fuel tank. A vapor passage for guiding the fuel to the canister, a recovery passage for collecting the evaporated fuel adsorbed in the canister into the fuel tank, a relief means for relieving a part of the fuel discharged from the fuel pump into the fuel tank, Negative pressure generating means for generating a negative pressure using a part of the fuel discharged from the fuel pump, and the evaporated fuel adsorbed in the canister by the negative pressure by the negative pressure generating means passes through the recovery passage The present invention relates to an evaporative fuel processing device that is recovered in a fuel tank.

  There exists following patent document 1 as this kind of evaporative fuel processing apparatus. In the evaporative fuel processing apparatus of Patent Document 1, negative pressure generating means is provided on a relief passage branched from a pressure regulator as relief means. Therefore, the negative pressure generating means communicates indirectly with the fuel pump via the pressure regulator. In this case, when the fuel pump is driven during operation of the automobile, a part of the fuel discharged from the fuel pump is relieved from the pressure regulator into the fuel tank as surplus fuel. At this time, negative pressure is generated by introducing surplus fuel relieved from the pressure regulator to the negative pressure generating means. The fuel pressure supplied from the fuel pump to the engine is regulated by a pressure regulator.

JP 2002-235608 A

  In Patent Document 1, the amount of fuel discharged from the fuel pump (constant) = the amount of fuel supplied to the engine + the surplus fuel relief amount by the pressure regulator. Since the negative pressure generating means is provided on the relief passage branched from the pressure regulator, the amount of fuel introduced into the negative pressure generating means = the surplus fuel relief amount by the pressure regulator. That is, the amount of fuel introduced into the negative pressure generating means, and hence the degree of negative pressure by the negative pressure generating means based on this, depends on the amount of surplus fuel relief by the pressure regulator. With this, a sufficient negative pressure cannot be secured stably.

  In order to solve this problem, it is conceivable that the negative pressure generating means communicates directly with the fuel pump separately from the pressure regulator. However, even if the negative pressure generating means and the fuel pump are directly connected in the configuration as in Patent Document 1, a new problem arises. Specifically, when the negative pressure generating means and the fuel pump are in direct communication, as shown in FIG. 6, the amount of fuel discharged from the fuel pump (constant) = the amount of fuel supplied to the engine + the surplus fuel by the pressure regulator This is the amount of relief plus the amount of fuel introduced into the negative pressure generating means. In this case, since the negative pressure generating means is in direct communication with the fuel pump, there is an advantage that the amount of fuel introduced into the negative pressure generating means is stabilized. However, on the other hand, the maximum amount of fuel supplied to the engine is reduced by the amount of fuel introduced into the negative pressure generating means. In addition, if a sufficient amount of fuel is introduced into the negative pressure generating means, the amount of fuel supplied to the engine may be insufficient. For example, in a situation where a large amount of fuel is required in the engine, such as when the accelerator is fully open, as shown by the shaded area in FIG. 6, (fuel supply amount to the engine + fuel introduction amount to the negative pressure generating means + excess fuel by the pressure regulator) The theoretical value of (relief amount) may exceed the discharge amount of the fuel pump, and the fuel supply amount to the engine may be insufficient. On the other hand, if a sufficient amount of fuel is supplied to the engine, the amount of fuel introduced to the negative pressure generating means is reduced.

  Therefore, for example, when a large amount of fuel is required in the engine, shortage of fuel supply to the engine can be avoided as shown in FIG. As such a fuel introduction amount control means, for example, a solenoid valve can be cited, but a new problem arises that it is impossible to generate a negative pressure when the valve is closed by simply shutting off the fuel introduction by the solenoid valve. . Moreover, in Patent Document 1, since the negative pressure generating means is provided on the relief passage, the fuel introduction amount control means cannot be provided upstream of the negative pressure generating means. This is because if the flow rate control means is provided upstream of the negative pressure generating means on the relief passage, the pressure regulating action by the pressure regulator becomes unstable.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and an object thereof is to provide an evaporative fuel processing apparatus that can stably maintain a sufficient negative pressure without causing a shortage of fuel supply to an internal combustion engine.

  The present invention relates to a fuel tank that stores fuel, a fuel pump that supplies fuel in the fuel tank to an internal combustion engine, a canister that adsorbs evaporated fuel generated in the fuel tank, and evaporated fuel from the fuel tank. A vapor passage for guiding the fuel to the canister, a collection passage for collecting the evaporated fuel adsorbed in the canister into the fuel tank, and a part of the fuel discharged from the fuel pump is relieved into the fuel tank. Relief means and negative pressure generating means for generating a negative pressure using a part of the fuel discharged from the fuel pump, and is adsorbed in the canister by the negative pressure generated by the negative pressure generating means. The evaporative fuel processing apparatus collects the evaporated fuel in the fuel tank through the recovery passage, and the relief means passes the relief passage through the fuel. While being communicated amplifier and communication, the negative pressure generating means is communicated directly with the fuel pump via a further fuel introduction passage and the relief passage. And it has the fuel introduction amount control means which can be increased / decreased while maintaining the fuel introduction amount from the fuel pump to the negative pressure generating means.

  In the present invention, the fuel introduction amount is increased or decreased according to various situations while securing the fuel introduction amount to the negative pressure generating means to some extent. Therefore, the relief amount by the relief means is constant (fixed amount) unlike the prior art. Here, it can be said that the relief means is a pressure adjusting means for adjusting the fuel pressure supplied from the fuel pump to the internal combustion engine. Therefore, the amount of relief by the relief means may be a minimum amount that can exert the pressure adjusting action. Therefore, in the present invention, the surplus fuel can be introduced into the negative pressure generating means as an increased amount while ensuring the pressure regulating action by the relief means at the minimum, instead of relieving the surplus fuel from the relief means as in the prior art. Attention.

  According to this, since the negative pressure generating means is directly communicated with the fuel pump via the fuel introduction passage different from the relief passage, the fuel discharge amount from the fuel pump (constant) = the fuel supply amount to the engine + The amount of fuel introduced into the relief amount by the relief means + the negative pressure generating means. Therefore, the amount of fuel introduced into the negative pressure generating means is not directly affected by the relief amount by the relief means. Thus, the fuel introduction amount control means can be provided while ensuring a stable pressure adjusting action by the relief means. In addition, the relief means may ensure a relief amount that can adjust the fuel pressure supplied to the internal combustion engine to the minimum. Therefore, the fuel introduction amount to the negative pressure generating means can be increased accordingly. According to the fuel introduction amount control means of the present invention, since the fuel introduction amount from the fuel pump to the negative pressure generation means is always maintained at a predetermined amount, the negative pressure can be stably generated. In addition, since the fuel introduction amount can be controlled to increase or decrease according to various situations, for example, even when a large amount of fuel is required in the engine, a shortage of fuel supply to the engine can be reliably avoided.

  As the fuel introduction amount control means, for example, an electromagnetic valve whose opening / closing timing is controlled by a control device can be used. The solenoid valve can only switch between the shut-off state (valve closed state) and the communication state (valve open state) of the fuel introduction passage, and the valve opening amount cannot be directly controlled. Therefore, in this case, the amount of fuel introduced into the negative pressure generating means is maintained by controlling the duty ratio determined by the valve opening time / (valve opening time + valve closing time) of the electromagnetic valve by the control device. You can increase or decrease. Specifically, the solenoid valve is repeatedly opened and closed within a short period of time, and the valve opening time ratio in one cycle is controlled with one opening and closing as one cycle. The overall fuel introduction amount can be increased or decreased without interruption.

  The control device stores in advance a duty ratio map corresponding to the fuel introduction amount to be introduced into the negative pressure generating means. Therefore, the amount of fuel introduced into the negative pressure generating means is actually controlled based on the duty ratio map. Thus, it is not necessary to calculate the duty ratio sequentially in the control means based on the fuel introduction amount to be introduced into the negative pressure generating means, and it is possible to increase / decrease the fuel introduction amount accurately and quickly.

  In the present invention, the amount of fuel introduced into the negative pressure generating means is calculated by the discharge amount of the fuel pump− (fuel supply amount to the internal combustion engine + relief amount by the relief means). At this time, since the discharge amount of the fuel pump and the relief amount by the relief means are constant, the fuel introduction amount to the negative pressure generating means varies substantially according to the fuel supply amount to the internal combustion engine. Therefore, in order to control the fuel introduction amount, it is only necessary to grasp the fuel supply amount, and the control program (calculation program) can be simplified.

  The following means can be cited as means for grasping the fuel supply amount. As a first means, since the fuel discharged from the fuel pump is injected and supplied from the fuel injection valve to the internal combustion engine through the fuel supply passage, the amount of fuel supplied to the internal combustion engine is determined as the fuel injection valve. It can obtain | require by detecting the fuel injection quantity from. The fuel injection amount is controlled based on a fuel supply amount map corresponding to the intake air amount to the internal combustion engine and the rotational speed of the internal combustion engine, which is stored in advance in the control device. Therefore, as a second means, the fuel supply amount to the internal combustion engine can be obtained based on the fuel supply amount map by detecting the intake air amount and the rotational speed of the internal combustion engine.

  If the fuel supply amount to the internal combustion engine is obtained from the fuel injection amount from the fuel injection valve, the actual fuel supply amount can be obtained, and the fuel introduction amount to the negative pressure generating means can be accurately controlled. On the other hand, if the fuel supply amount to the internal combustion engine is obtained from the intake air amount and the rotation speed of the internal combustion engine based on the fuel supply amount map, the fuel injection amount from the fuel injection valve can be predicted. The amount of fuel introduced can be quickly controlled without the need for detection.

  According to the fuel vapor processing apparatus of the present invention, a sufficient negative pressure can be stably maintained without causing a shortage of fuel supply to the internal combustion engine.

It is a schematic diagram which shows the basic composition of an evaporative fuel processing apparatus. It is a longitudinal cross-sectional view of an aspirator. It is a graph which shows the fuel flow volume in this invention. It is the 1st flow which controls the amount of fuel introduction to an aspirator in a control device. It is a 2nd flow which controls the fuel introduction amount to an aspirator in a control apparatus. It is a fuel flow rate graph which shows the problem of a prior art. It is a fuel flow rate graph which shows the 2nd problem of a prior art.

  Hereinafter, representative embodiments of the present invention will be described, but the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention. In particular, the fuel vapor processing apparatus according to the present invention includes a fuel tank, a fuel pump, a canister, a vapor passage, a recovery passage, a relief means, and a negative pressure generating means, which are essential components, and the negative pressure generated by the negative pressure generating means. Various other components can be added as long as they have a basic configuration for recovering the evaporated fuel. The evaporative fuel processing apparatus of the present invention can be suitably applied to vehicles such as automobiles that use highly volatile fuel (for example, gasoline) as fuel.

Example 1
As shown in FIG. 1, the evaporative fuel processing device includes a fuel tank 1 that stores fuel F, a fuel pump 11 that pumps fuel F in the fuel tank 1 to an internal combustion engine 30, and a fuel tank 1 The canister 10 that adsorbs the evaporated fuel (vapor) generated in the above, the vapor passage 2 that guides the evaporated fuel in the fuel tank 1 to the canister 10, and the evaporated fuel that is adsorbed in the canister 10 is recovered in the fuel tank 1. A negative pressure is generated by using the recovery passage 3, a pressure regulator 13 that relieves a part of the fuel F discharged from the fuel pump 11 into the fuel tank 1, and a part of the fuel discharged from the fuel pump 11. The aspirator 12 is provided. The aspirator 12 corresponds to the negative pressure generating means of the present invention, and the pressure regulator 13 corresponds to the relief means of the present invention.

  The fuel tank 1 is a sealed tank. The fuel pump 11 is installed at the bottom of the fuel tank 1 and pumps the fuel F through the fuel supply passage 4. A pressure regulator 13 is communicated with the fuel pump 11 via a relief passage 7 branched from the fuel supply passage 4. An aspirator 12 is directly connected to the fuel pump 11 through a fuel introduction passage 6 branched from the fuel supply passage 4 at a portion different from the relief passage 7. The fuel supply passage 4 is connected to an injector 32 that injects fuel into an intake passage 31 formed in an intake manifold of the engine 30. A throttle valve 33 that controls the amount of intake air when the engine is driven is provided in the intake passage 31. The fuel tank 1 is provided with a pressure sensor P that detects the internal pressure of the fuel tank 1. A detection signal from the pressure sensor P is input to an engine control unit (ECU) 25. Further, the intake air amount sucked from the intake passage 31, the fuel injection amount from the injector 32, the rotational speed of the engine 30, and the like are also input to the EUC 25. The intake air amount is controlled by the opening degree of the throttle valve 33 corresponding to the depression amount of an accelerator (not shown).

  On the fuel introduction passage 6, a fuel introduction valve 21 that controls the amount of fuel F introduced from the fuel pump 11 to the aspirator 12 is provided. The fuel introduction valve 21 is composed of an electromagnetic valve whose opening / closing timing is controlled by the ECU 25. The ECU 25 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and the like. A predetermined control program (details will be described later) is stored in advance in the ROM, and the CPU controls the fuel introduction valve 21 and the like at a predetermined timing based on the control program. The ECU 25 corresponds to the control device of the present invention, and the fuel introduction valve 21 corresponds to the fuel introduction amount control means of the present invention. A pressure control valve 22 is provided on the vapor passage 2 to hold the internal pressures of the fuel tank 1 and the canister 10 within a certain range. The pressure control valve 22 is a bidirectional check valve including a positive pressure valve 22a and a negative pressure valve 22b. The pressure control valve 22 is normally closed. When the internal pressure of the fuel tank 1 becomes a predetermined value or more, the positive pressure valve 22a is opened, and when the internal pressure of the fuel tank 1 becomes a predetermined value or less, the negative pressure valve 22b is opened. The Further, when the evaporated fuel adsorbed in the canister 10 is desorbed and collected, the pressure control valve 22 holds the inside of the canister 10 in a negative pressure state. The set pressure of the pressure control valve 22 is set from the viewpoint of preventing damage to the fuel tank 1, and may be, for example, about ± 5 kPa. In this case, the internal pressure of the fuel tank 1 is controlled to be maintained at about +5 kPa to −5 kPa. A recovery passage valve 23 is provided on the recovery passage 3 as an opening / closing means for switching between the communication state and the shut-off state of the recovery passage 3. The collection passage valve 23 is constituted by an electromagnetic valve that is controlled to be opened and closed by the ECU 25.

  The canister 10 is a hermetically sealed container, and the inside thereof is filled with an adsorbent C made of activated carbon or the like that can adsorb and desorb evaporated fuel. The evaporated fuel introduced into the canister 10 is adsorbed by the adsorbent C, but the air component permeates. The canister 10 is connected to an air passage 5 whose front end is open to the atmosphere. An atmospheric passage valve 20 is also mounted on the atmospheric passage 5 as an opening / closing means for switching the communication state and the blocking state of the atmospheric passage 5. The atmospheric passage valve 20 is also an electromagnetic valve whose opening and closing is controlled by the ECU 25.

  The aspirator 12 is provided at the tip on the collection passage 3. The aspirator 12 is provided to recover the evaporated fuel adsorbed in the canister 10 by applying a negative pressure into the canister 10 via the recovery passage 3. A part of the fuel F discharged from the fuel pump 11 and pumped through the fuel supply passage 4 is introduced into the aspirator 12 through the fuel introduction passage 6. As shown in FIG. 2, the aspirator 12 includes a venturi part 41 and a nozzle part 45. The venturi section 41 includes a throttle 42, a tapered inlet diameter-reduced portion 43 provided on the upstream side of the throttle 42 in the fuel flow direction, and a tapered outlet expansion portion provided on the downstream side of the throttle 42 in the fuel flow direction. 44, the inlet diameter-reduced part 43, the throttle 42, and the outlet widened part 44 are formed coaxially. A suction port 41p to which the recovery passage 3 is connected is formed at the upstream end portion of the inlet diameter-reduced portion 43 of the venturi portion 41. On the other hand, the nozzle portion 45 includes a nozzle body 46 that is coaxially accommodated inside the inlet diameter-reduced portion 43 of the venturi portion 41, and the injection port 46 p of the nozzle body 46 is in the vicinity of the throttle 42 of the venturi portion 41. It is positioned. Further, a fuel introduction port 47 to which the fuel introduction passage 6 is connected is formed at the base end portion (the side opposite to the injection port 46p) of the nozzle body 46.

  When the fuel F is introduced into the aspirator 12 from the fuel introduction port 47, the introduced fuel F is injected from the injection port 46 p of the nozzle body 46, and the central portion of the throttle 42 and the outlet widening portion 44 of the venturi portion 41. It flows at high speed in the axial direction. As a result, negative pressure is generated in the vicinity of the throttle 42 of the venturi section 41, and negative pressure also acts on the recovery passage 3 connected to the suction port 41p and the canister 10 connected upstream thereof. By this negative pressure, the evaporated fuel adsorbed in the canister 10 is desorbed (purged). The evaporated fuel desorbed and recovered from the canister 10 is discharged from the discharge port 12a together with the fuel F injected from the nozzle body 46.

  The aspirator 12 may be provided in the gas layer of the fuel tank 1 (above the liquid level of the fuel F), or may be provided in the liquid tank under the fuel tank 1. When it is provided in the gas layer, it is preferably provided downward, and when it is provided in a liquid immersion state, it is preferably provided downward. If the aspirator 12 is provided in the air layer, the fuel F in the fuel tank 1 can be prevented from flowing back to the recovery passage 3 side via the aspirator 12 immediately after the fuel introduction from the fuel pump 11 is stopped. Furthermore, if it is provided downward in the air layer, it is also possible to avoid the fuel F in the aspirator 12 flowing back to the recovery passage 3 side immediately after the fuel introduction from the fuel pump 11 is stopped. On the other hand, when the aspirator 12 is provided in a liquid-immersed state and operated with the fuel F, the negative pressure tends to be larger than that in the case where the aspirator 12 is disposed in the air layer, and there is an advantage that the evaporated fuel can be efficiently recovered from the canister 10. . Furthermore, if it is provided upward in the fuel F, the time lag from when the fuel pump 11 is driven until the negative pressure is generated is reduced, and the responsiveness is improved. However, if the aspirator 12 is in the fuel F, immediately after the fuel introduction from the fuel pump 11 is stopped, the fuel F in the fuel tank 1 may flow backward to the recovery passage 3 side via the aspirator 12. Therefore, when the aspirator 12 is provided in a liquid immersion state, it is preferable to provide a backflow prevention means such as a check valve on the recovery passage 3.

  Next, a processing mechanism by the evaporated fuel processing apparatus having the above configuration will be described. The air passage valve 20 on the air passage 5 is normally open (when off) and is closed when energized (ON) by the ECU 25. On the other hand, the recovery passage valve 23 on the recovery passage 3 is normally closed (when off) and is opened by energization (ON) by the ECU 25. When the fuel pump 11 is not driven, such as when parking or refueling, when the internal pressure of the fuel tank 1 becomes equal to or higher than the set pressure of the pressure control valve 22 due to generation of fuel vapor or refueling, the positive pressure valve of the pressure control valve 22 22 a opens, and the gas (air and evaporated fuel) in the fuel tank 1 flows into the canister 10 through the vapor passage 2. Then, the evaporated fuel is selectively adsorbed and held by the adsorbent C in the canister 10. The remaining air passes through the adsorbent C and is dissipated from the canister 10 through the atmospheric passage 5 into the atmosphere, and the pressure of the fuel tank 1 is released. Thus, a significant increase in internal pressure of the fuel tank 1 is suppressed while avoiding air pollution, and the fuel tank 1 is protected. When the internal pressure of the fuel tank 1 is within the set pressure range of the pressure control valve 22, the pressure control valve 22 is closed, so that the fuel tank 1 is in a sealed state. On the other hand, when the internal pressure of the fuel tank 1 becomes equal to or lower than the set pressure of the pressure control valve 22 due to a temperature drop or the like, the negative pressure valve 22b of the pressure control valve 22 is opened, and the outside air passes through the atmosphere passage 5, the canister 10, and the vapor passage 2. The fuel flows into the fuel tank 1 in this order. As a result, a significant decrease in internal pressure of the fuel tank 1 is suppressed, and the fuel tank 1 is protected.

  During driving of the fuel pump 11 such as during traveling, the atmospheric passage valve 20 is basically controlled to close and the recovery passage valve 23 is controlled to open. In addition, a part of the fuel F discharged from the fuel pump 11 is supplied from the fuel supply passage 4 to the aspirator 12 through the fuel introduction passage 6. As a result, a negative pressure is generated by the aspirator 12, the evaporated fuel adsorbed in the canister 10 is sucked and desorbed, and is recovered from the aspirator 12 into the fuel tank 1 through the recovery passage 3. At this time, the inside of the canister 10 is kept at a negative pressure by the pressure control valve 22. When the internal pressure of the fuel tank 1 becomes equal to or higher than the set pressure of the pressure control valve 22 due to fuel recovery, re-evaporation of evaporated fuel, etc., the evaporated fuel in the fuel tank 1 passes through the vapor passage 2 and canister 10 as in parking. Flows in. As described above, during the normal recovery of the evaporated fuel, the atmospheric passage valve 20 on the atmospheric passage 5 is basically closed, so that outside air does not flow into the fuel tank 1 and the fuel tank 1 Increase in pressure is suppressed. On the other hand, another part of the fuel F discharged from the fuel pump 11 is relieved from the pressure regulator 13 into the fuel tank 1 through the relief passage 7. The amount of relief by the pressure regulator 13 in this embodiment is set to an amount that can adjust the fuel pressure supplied through the fuel supply passage 4 to the minimum (see FIG. 3).

  However, when the external environment is high temperature, or when the fuel F becomes high temperature due to the driving heat of the engine or the fuel pump 11 and a large amount of evaporated fuel is generated, the internal pressure of the fuel tank 1 can also rise rapidly. In such a case, when the pressure detected by the pressure sensor P becomes equal to or higher than a predetermined value, the atmospheric passage valve 20 is controlled to open and the recovery passage valve 23 is controlled to close, and the fuel tank 1 is connected via the canister 10. The inside air is vented. Thereby, a significant pressure increase in the fuel tank 1 is suppressed. When the pressure detected by the pressure sensor P becomes lower than a predetermined value due to the pressure release of the fuel tank 1, the atmospheric passage valve 20 is controlled to close again and the recovery passage valve 23 is controlled to open. Thus, by providing the recovery passage valve 23 on the recovery passage 3, it is possible to control the supply of evaporated fuel to the aspirator 12 regardless of the operation of the aspirator 12 accompanying the drive of the fuel pump 11. Appropriate processing can be performed according to the internal pressure state.

  The fuel pressure-fed through the fuel supply passage 4 is injected from the injector 32 into the intake passage 31 and supplied to the combustion chamber of the engine 30 together with the intake air. The fuel supply amount to the engine 30, that is, the fuel injection amount from the injector 32 is controlled by the ECU 25 in accordance with the load and the rotational speed of the engine 30. The load of the engine 30 corresponds to the intake air amount. Specifically, if the intake air amount and the rotational speed are low, the fuel injection amount from the injector 32 is small. On the other hand, if the intake air amount and the rotational speed are high, the fuel injection amount from the injector 32 becomes large. Incidentally, the load tendency of the engine 30 and the fluctuation tendency of the rotational speed do not always match. For example, if the accelerator is stepped on greatly during high-speed gear traveling, the load on the engine 30 increases, but the rotational speed does not necessarily become higher than the rotational speed during low-speed gear traveling. In addition, the EUC 25 stores a fuel supply amount map corresponding to the load and the rotational speed of the engine 30 in advance, and the intake air amount and the rotational speed of the engine 30 are detected and input to the EUC 25 while the vehicle is traveling. Then, the EUC 25 controls the fuel injection amount from the injector 32 based on the fuel supply amount map from the detection signal.

  On the other hand, the amount of fuel introduced from the fuel pump 11 to the aspirator 12 is controlled by a fuel introduction valve 21 provided on the fuel introduction passage 6. The fuel introduction valve 21 made of an electromagnetic valve repeats opening and closing quickly in a short time, and the ECU 25 controls the duty ratio determined by the valve opening time / (valve opening time + valve closing time). As shown in FIG. 3, the surplus fuel is increased or decreased according to the amount of fuel supplied to the engine 30 while maintaining a certain amount of fuel introduced. The EUC 25 stores in advance a duty ratio map corresponding to the fuel introduction amount to be introduced into the aspirator 12, and the fuel introduction amount into the aspirator 12 is controlled based on the duty ratio map.

  Based on this premise, a method for controlling the amount of fuel introduced into the aspirator 12 will be described with reference to FIG. While the fuel pump 11 is being driven, the fuel injection amount from the injector 32 is detected and input to the EUC 25 (step S1). The fuel injection amount is an actual fuel supply amount. Next, in the EUC 25, the fuel introduction amount to the aspirator 12 is calculated by a calculation formula based on the discharge amount of the fuel pump 11− (the fuel supply amount to the engine 30 + the relief amount by the pressure regulator 13) (step S2). Note that the relief amount by the pressure regulator 13 is constant, and the relief amount is also input to the EUC 25 in advance. Finally, the fuel introduction valve 21 is controlled to a predetermined duty ratio by referring to the calculated fuel introduction amount in a duty ratio map stored in advance (step S3). While the fuel pump 11 is being driven, this operation is repeated, so that excess fuel is increased or decreased according to the amount of fuel supplied to the engine 30. Therefore, even when a large amount of fuel is required in the engine 30, there is no shortage of fuel supply.

  When the fuel pump 11 is stopped, the fuel introduction valve 21 is closed, and fuel introduction into the aspirator 12 is also stopped while the fuel pressure in the fuel supply passage 4 is maintained.

(Example 2)
In the first embodiment, the fuel injection amount from the injector 32 is detected as the fuel supply amount to the engine 30 and the fuel introduction amount to the aspirator 12 is controlled. However, the fuel is supplied based on the predicted fuel injection amount from the injector 32. The amount introduced can also be controlled. That is, the fuel injection amount from the injector 32 is controlled based on a fuel supply amount map corresponding to the intake air amount and the engine speed, but if the intake air amount and the engine speed can be detected, the fuel can be detected. The fuel injection amount can be predicted based on the supply amount map. Therefore, in the second embodiment, the amount of intake air to the engine 30 and the rotation speed of the engine 30 are detected, and the fuel introduction amount is controlled based on the fuel supply amount map. That is, the fuel supply amount map is used for fuel introduction amount control simultaneously with fuel injection amount control.

  Specifically, as shown in FIG. 5, during the driving of the fuel pump 11, the intake air amount to the engine 30 and the rotational speed of the engine 30 are detected and input (step S1). Next, in the EUC 25, the fuel supply amount is grasped by referring to the detection signal of the intake air amount and the rotational speed to the fuel supply amount map, and the discharge amount of the fuel pump 11− (the fuel supply amount to the engine 30 + the pressure regulator 13) The fuel introduction amount to the aspirator 12 is calculated by a calculation formula based on the relief amount (step S2). Finally, the fuel introduction valve 21 is controlled to a predetermined duty ratio by referring to the calculated fuel introduction amount in a duty ratio map stored in advance (step S3). By repeating this operation while the fuel pump 11 is being driven, the excess fuel can be increased or decreased in accordance with the amount of fuel supplied to the engine 30 as in the first embodiment. According to this, it is possible to quickly control the fuel introduction amount without the trouble of detecting the actual fuel injection amount.

(Modification)
In the above embodiment, the solenoid valve (fuel introduction valve 21) provided on the fuel introduction passage 6 is used as the fuel introduction amount control means. However, the fuel introduction amount control means is not necessarily provided on the fuel introduction passage 6. Moreover, it may not be a solenoid valve. For example, the fuel introduction amount control means is arranged in the nozzle portion 45 of the aspirator 12 so as to be able to advance and retreat in the axial direction with respect to the nozzle body 46, and the fuel injection amount from the nozzle body 46 can be controlled according to the advance and retreat position. It can also be a needle valve. In this case, an actuator for advancing and retracting the needle valve is provided in the nozzle portion 45 of the aspirator 12.

  The pressure control valve 22 provided on the vapor passage 2 may be an electromagnetic valve whose opening and closing is controlled by the ECU, similarly to the recovery passage valve 23. In this case, the pressure control valve 22 is always closed, and it may be set so that the valve opening control is performed when the pressure sensor P detects that the internal pressure of the fuel tank 1 has become a predetermined value or more.

  It is also possible to provide a pressure control valve between the canister 10 on the atmospheric passage 5 and the atmospheric passage valve 20 to keep the inside of the canister 10 at a negative pressure. Further, heating means such as a heater for heating the adsorbent C can be provided in the canister 10. When the evaporated fuel is recovered, the heating means is driven to heat the adsorbent C, so that the desorption efficiency is improved and the evaporated fuel recovery efficiency is improved. In addition, a separation means such as a separation membrane that can separate the fuel component and the air component is provided at an appropriate position of the evaporative fuel processing apparatus, and a configuration in which the dilution gas is circulated while the fuel component is concentrated and recovered by the separation means is adopted. You can also.

DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Vapor passage 3 Recovery passage 4 Fuel supply passage 6 Fuel introduction passage 7 Relief passage 10 Canister 11 Fuel pump 12 Aspirator 13 Pressure regulator 21 Fuel introduction valve 30 Engine 31 Intake passage 32 Injector 41 Venturi portion 45 Nozzle portion 46 Nozzle body C Adsorbent F Fuel P Pressure sensor

Claims (6)

A fuel tank for storing fuel, a fuel pump for supplying the fuel in the fuel tank to the internal combustion engine, a canister for adsorbing the evaporated fuel generated in the fuel tank, and the evaporated fuel from the fuel tank to the canister A vapor passage for guiding, a recovery passage for collecting the evaporated fuel adsorbed in the canister into the fuel tank, and a relief means for relieving a part of the fuel discharged from the fuel pump into the fuel tank; Negative pressure generating means for generating a negative pressure using a part of the fuel discharged from the fuel pump, and the evaporated fuel adsorbed in the canister by the negative pressure generated by the negative pressure generating means. An evaporative fuel processing device that recovers into the fuel tank through the recovery passage,
The relief means is in communication with the fuel pump via a relief passage;
The negative pressure generating means is in direct communication with the fuel pump via a fuel introduction passage different from the relief passage,
An evaporative fuel processing apparatus comprising fuel introduction amount control means capable of increasing or decreasing while maintaining the fuel introduction amount from the fuel pump to the negative pressure generating means. It is an evaporative fuel processing apparatus of Claim 1, Comprising:
The fuel introduction amount control means is a solenoid valve whose opening and closing timing is controlled by a control device;
By controlling the duty ratio determined by the valve opening time / (valve opening time + valve closing time) of the electromagnetic valve by the control device, it is increased or decreased while maintaining the amount of fuel introduced into the negative pressure generating means. An evaporative fuel processing apparatus. The evaporative fuel processing apparatus according to claim 2,
In the control device, a duty ratio map corresponding to the fuel introduction amount to be introduced into the negative pressure generating means is stored in advance,
An evaporative fuel processing apparatus, wherein the amount of fuel introduced into the negative pressure generating means is controlled based on the duty ratio map. An evaporative fuel processing apparatus according to any one of claims 1 to 3,
The evaporative fuel processing apparatus is characterized in that the fuel introduction amount to the negative pressure generating means is calculated by the discharge amount of the fuel pump− (fuel supply amount to the internal combustion engine + relief amount by the relief means). . It is an evaporative fuel processing apparatus of Claim 4, Comprising:
The fuel discharged from the fuel pump is injected and supplied from a fuel injection valve to the internal combustion engine through a fuel supply passage.
The fuel supply amount to the internal combustion engine is obtained by detecting the fuel injection amount from the fuel injection valve. It is an evaporative fuel processing apparatus of Claim 4, Comprising:
In the control device, a fuel supply amount map corresponding to the intake air amount and the rotational speed to the internal combustion engine is stored in advance,
The fuel supply amount to the internal combustion engine is obtained based on the fuel supply amount map by detecting the intake air amount and the rotational speed.

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