JP2008008255A - Controller for negative pressure generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a negative pressure generator capable of supplying evaporated fuel with priority to an internal combustion engine used together with the negative pressure generator, and capable of restraining an ejector function from being limited unnecessarily when the evaporated fuel is preferentially supplied. <P>SOLUTION: A purge preference control means for controlling a VSV 1 is provided to reduce an amount of intake air flowing in the ejector 30 according to the supply of the evaporated fuel to the internal combustion engine 50, more concretely, to close a flow passage into a full closed state so as to bring the amount of intake air flowing in the ejector 30 into zero, in an ECU 40A for controlling the negative pressure generator 100 having the ejector 30 for negative pressure more negative than negative pressure taken out of an intake manifold 14, and the VSV 1 for changing the amount of intake air flowing in the ejector 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for a negative pressure generating device, and more particularly to a control device for a negative pressure generating device that controls a negative pressure generating device configured with an ejector.

  Conventionally, in a vehicle, a negative pressure larger than the negative pressure to be taken out from the intake passage of the intake system of the internal combustion engine communicating with each cylinder from the atmosphere (hereinafter also simply referred to as the intake system of the internal combustion engine) is supplied to the brake booster. An ejector is used to do this. The ejector is generally disposed in a bypass path that bypasses the throttle valve, and generates a larger negative pressure due to the venturi effect. As a technique using this ejector, for example, Patent Document 1 discloses a negative pressure source device for a negative pressure booster using an ejector.

Sho 62-214245

  By the way, a purge system has been conventionally known in which fuel vapor performance is improved by supplying evaporated fuel to an internal combustion engine using the negative pressure of the intake system of the internal combustion engine. In this purge system, when the negative pressure of the intake system of the internal combustion engine decreases, the supply flow rate of the evaporated fuel (hereinafter also simply referred to as the purge flow rate) decreases, so that a large amount of evaporated fuel cannot be supplied to the internal combustion engine. There is such a problem. On the other hand, when the ejector functions, the intake air flowing through the bypass passage acts to lower the negative pressure of the intake system of the internal combustion engine. For this reason, if the ejector is also functioning at the same time as the supply of the evaporated fuel (hereinafter simply referred to as purge) is performed, the fuel amount of the evaporated fuel (hereinafter also simply referred to as the purge amount) as the purge flow rate decreases. There is a risk that the evaporative fuel cannot be used effectively.

  In particular, in an internal combustion engine configured to open a throttle to reduce pump loss such as a direct injection engine, the negative pressure of the intake system is often decreased, and it is difficult to efficiently use evaporated fuel. It has become.

  Therefore, the present invention has been made in view of the above problems, and can give priority to the supply of evaporated fuel to an internal combustion engine in which the negative pressure generator is used, and more than necessary to prioritize the supply of evaporated fuel. It is an object of the present invention to provide a control device for a negative pressure generator that can suppress the function of an ejector from being restricted.

  In order to solve the above-described problems, the present invention provides an ejector that generates a negative pressure larger than the negative pressure to be taken out from an intake passage of an intake system of an internal combustion engine, and an intake air amount that changes the amount of intake air flowing through the ejector A control device for a negative pressure generating device configured to control the negative pressure generating device, the intake air flowing through the ejector according to the supply of evaporated fuel to the internal combustion engine It further comprises purge priority control means for controlling the intake air amount changing means so as to reduce the amount of exhaust gas. That is, according to the present invention, since the negative pressure of the intake system of the internal combustion engine can be increased by restricting the function of the ejector according to the supply of the evaporated fuel, the supply of the evaporated fuel can be prioritized.

  The term “depending on the supply of the evaporated fuel” is not limited to whether or not the evaporated fuel is supplied, but also includes the supply state. Specifically, for example, the flow path of the purge flow rate adjusting means for further adjusting the supply flow rate of the evaporated fuel when the supply of the evaporated fuel is not limited to the case where the supply of the evaporated fuel is changed to a certain state. This also includes responding to the degree of shielding. That is, when the intake air amount changing means is realized by, for example, a flow rate adjusting valve capable of changing the degree of shielding of the flow path, the purge priority control means performs purging according to the degree of flow shielding of the purge flow rate adjusting means. It is also possible to control the intake air amount changing means so that the degree of flow passage shielding of the intake air amount changing means increases as the degree of flow passage shielding of the flow rate adjusting means decreases. Thereby, priority can be given to the supply of the evaporated fuel so as to be compatible with the function of the ejector to some extent.

  The present invention also includes an ejector for generating a negative pressure larger than the negative pressure to be taken out from the intake passage of the intake system of the internal combustion engine, and an intake air amount changing means for changing the amount of intake air flowing through the ejector. A control device for a negative pressure generating device for controlling a negative pressure generating device configured, wherein a purge flow rate adjusting means for adjusting the supply flow rate of the evaporated fuel is opened so as to communicate the flow path at a predetermined degree or more. In this case, the purge priority control means controls the intake air amount changing means so as to reduce the amount of intake air flowing through the ejector. That is, in a state where a large amount of evaporated fuel is to be used, the purge flow rate adjusting means is generally wide open to increase the purge flow rate. Therefore, according to the present invention, according to the state where a large amount of evaporated fuel is to be used. Therefore, priority can be given to the supply of evaporated fuel.

  In the present invention, the amount of intake air flowing through the ejector may be reduced to zero. In particular, when giving priority to the supply of the evaporated fuel, it is preferable to reduce the amount of intake air flowing through the ejector, for example, as in the present invention. When the intake air amount changing means is realized by, for example, a flow rate adjusting valve that can change the degree of shielding of the flow path, this flow rate adjusting valve is set so that the purge priority control means shields the flow path fully closed. The present invention can be realized by controlling. In addition, when the intake air amount changing means is realized by, for example, a control valve that can change the flow path to fully open or fully closed, the purge priority control means controls the control valve to fully close to realize the present invention. it can. In the above-described invention, the purge priority control means can also control the intake air amount changing means so as to shield the flow path at a predetermined degree so as not to completely stop the function of the ejector. Accordingly, the ejector function can be maintained to some extent while giving priority to the supply of the evaporated fuel.

  Further, according to the present invention, when the fuel concentration of the evaporated fuel is not more than a predetermined value, the purge priority control means does not control the intake air amount changing means so as to reduce the amount of intake air flowing through the ejector. Also good. Here, the case where the fuel concentration of the evaporated fuel (hereinafter also simply referred to as the purge concentration) is equal to or less than a predetermined value is an indicator of the shortage of available evaporated fuel, and the available evaporated fuel is insufficient. In some cases, the need for purging is scarce in the first place. Therefore, if priority is given to the supply of the evaporated fuel up to such a case, the function of the ejector is restricted more than necessary, which is inconvenient. The present invention has been made in view of the above points, and according to the present invention, it is possible to suppress the function of the ejector from being restricted more than necessary when giving priority to the supply of evaporated fuel.

  In the control device for the negative pressure brake negative pressure generator, the present invention can be configured to give priority to the ejector when the brake negative pressure is a predetermined value or less. In the case where the brake negative pressure becomes equal to or lower than the predetermined value and the braking effectiveness is deteriorated, the sufficient braking effectiveness can be secured by giving priority to the ejector.

  According to the present invention, it is possible to give priority to the supply of evaporated fuel to an internal combustion engine that is used together with the negative pressure generator, and it is also possible to prevent the function of the ejector from being restricted more than necessary when giving priority to the supply of evaporated fuel. It is possible to provide a control device for a possible negative pressure generator.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram schematically showing a control device for a negative pressure generating device according to the present embodiment, which is realized by an ECU (Electronic Control Unit) 40A, together with the negative pressure generating device 100. The components shown in FIG. 1 including the internal combustion engine 50 are mounted on a vehicle (not shown). The intake system 10 of the internal combustion engine 50 includes an air cleaner 11, an air flow meter 12, an electric throttle 13, an intake manifold 14, an intake port (not shown) communicating with each cylinder (not shown) of the internal combustion engine 50, and the configuration thereof. For example, intake pipes 15a, 15b and the like are appropriately disposed between the two. The air cleaner 11 is configured to filter the intake air supplied to each cylinder of the internal combustion engine 50, and communicates with the atmosphere via an air duct (not shown). The air flow meter 12 is configured to measure the intake flow rate and outputs a signal corresponding to the intake flow rate.

  The electric throttle 13 includes a throttle valve 13a, a throttle body 13b, a valve shaft 13c, and an electric motor 13d. The throttle valve 13a is configured to adjust the total intake flow rate supplied to each cylinder of the internal combustion engine 50 by changing the opening. The electric throttle 13 is also configured to adjust the intake flow rate in order to control the idle speed. The throttle body 13b is composed of a cylindrical member in which an intake passage is formed, and pivotally supports a valve shaft 13c of a throttle valve 13a disposed in the intake passage. The electric motor 13d is configured to change the opening degree of the throttle valve 13a under the control of the ECU 40A, and a step motor is adopted as the electric motor 13d. The electric motor 13d is fixed to the throttle body 13b, and its output shaft (not shown) is connected to the valve shaft 13c. The opening degree of the throttle valve 13a is detected by the ECU 40A based on an output signal from an encoder (not shown) incorporated in the electric throttle 13 (hereinafter simply referred to as an encoder).

  The throttle mechanism is preferably a throttle-by-wire system in which a throttle valve 13a such as an electric throttle 13 is driven by an actuator. However, the present invention is not limited to this. For example, a mechanical throttle mechanism in which the opening of the throttle valve 13a is changed in conjunction with an accelerator pedal (not shown) via a wire or the like instead of the electric throttle 13 may be applied. Good. The intake manifold 14 is configured to branch one intake passage on the upstream side corresponding to each cylinder of the internal combustion engine 50 on the downstream side, and distributes intake air to each cylinder of the internal combustion engine 50.

  The brake device 20 includes a brake pedal 21, a brake booster 22, a master cylinder 23, and a wheel cylinder (not shown). The brake pedal 21 operated by the driver to brake the rotation of the wheel is connected to an input rod (not shown) of the brake booster 22. The brake booster 22 is configured to generate an assist force with a predetermined boost ratio with respect to the pedal depression force, and a negative pressure chamber (not shown) internally partitioned on the master resin 23 side To the intake passage of the intake manifold 14. The output rod (not shown) of the brake booster 22 is further connected to the input shaft (not shown) of the master cylinder 23. The master cylinder 23 receives the assist force in addition to the pedal depression force. Hydraulic pressure is generated according to the applied force. The master cylinder 23 is connected to each wheel cylinder provided in a disc brake mechanism (not shown) of each wheel via a hydraulic circuit, and the wheel cylinder generates a braking force with the hydraulic pressure supplied from the master cylinder 23. . The brake booster 22 is not particularly limited as long as it is a pneumatic type, and may be a general one.

  The ejector 30 is configured to generate a negative pressure larger than the negative pressure to be taken out from the intake system 10, more specifically, the intake manifold 14, and supply it to the negative pressure chamber of the brake booster 22. The ejector 30 has an inflow port 31a, an outflow port 31b, and a negative pressure supply port 31c. Among these, the negative pressure supply port 31c is connected to the negative pressure chamber of the brake booster 22 by the air hose 5c. The inflow port 31a is connected to the intake passage of the intake pipe 15a by an air hose 5a, and the outflow port 31b is connected to the intake passage of the intake manifold 14 by an air hose 5b so as to sandwich the electric throttle 13, more specifically, the throttle valve 13a. ing. Thus, a bypass path B that bypasses the electric throttle 13 is formed by the air hoses 5 a and 5 b including the ejector 30. When the ejector 30 is not functioning, the negative pressure chamber of the brake booster 22 is connected to the intake manifold 14 via the air hose 5b, the outlet port 31b of the ejector 30, the negative pressure supply port 31c, and the air hose 5c. Negative pressure is supplied.

  A VSV (vacuum switching valve) 1 is interposed in the air hose 5a. The VSV 1 is configured to communicate and block the bypass path B under the control of the ECU 40A. In the present embodiment, a 2-position 2-port normally closed solenoid valve is employed. However, the present invention is not limited to this, and the VSV 1 may be another appropriate electromagnetic valve or the like, and may be, for example, a flow rate adjustment valve that can control the degree of shielding of the flow path. Further, the VSV 1 is configured to change the amount of intake air flowing through the ejector 30 and to function or stop the function of the ejector 30 by communicating and blocking the bypass passage B. In the present embodiment, the intake air amount changing means is realized by VSV1.

  FIG. 2 is a diagram schematically showing the internal configuration of the ejector 30. The ejector 30 includes a diffuser 32 inside. The diffuser 32 includes a tapered taper portion 32a, a divergent taper portion 32b, and a negative pressure extraction portion 32c corresponding to a passage communicating these. The tapered taper portion 32a is opened so as to face the inflow port 31a, and the divergent taper portion 32b is opened so as to face the outflow port 31b. Moreover, the negative pressure extraction part 32c is connected to the negative pressure supply port 31c. The inflow port 31a is provided with a nozzle 33 for injecting the inflowing intake air toward the tapered portion 32a. The intake air injected from the nozzle 33 flows through the diffuser 32, and further from the outflow port 31b to the air hose 5b. To leak. At this time, a high-speed jet is generated in the diffuser 32 to generate a large negative pressure in the negative pressure extraction portion 32c due to the venturi effect, and this negative pressure is further reduced from the negative pressure supply port 31c through the air hose 5c to the negative pressure chamber. To be supplied. Due to the function of the ejector 30, the brake booster 22 can obtain a larger negative pressure than when the brake booster 22 is taken out from the intake manifold 14. The internal flow path between the negative pressure extraction part 32c and the negative pressure supply port 31c, the internal flow path between the outflow port 31b and the negative pressure supply port 31c, and the air hose 5c connection part of the brake booster 22 The provided reverse support valves 34 are for preventing backflow. Further, the ejector 30 is not limited to the one having the internal structure shown in FIG. 2, and an ejector having another different internal structure may be applied instead of the ejector 30.

  The exhaust system 60 is configured to include an exhaust manifold 61, a three-way catalyst 62, a silencer (not shown), and an intake pipe appropriately disposed between these components. The exhaust manifold 61 is configured to join the exhaust from each cylinder, and the exhaust passage branched in correspondence with each cylinder is gathered into one exhaust passage on the downstream side. The three-way catalyst 62 is configured to purify exhaust gas, and performs oxidation of hydrocarbons HC and carbon monoxide CO and reduction of nitrogen oxides NOx. In the exhaust system 60, an A / F sensor 63 for linearly detecting the air-fuel ratio based on the oxygen concentration in the exhaust is upstream of the three-way catalyst 62, and the air-fuel ratio is based on the oxygen concentration in the exhaust from the stoichiometric air-fuel ratio. Also, oxygen sensors 64 for detecting whether the gas is rich or lean are respectively disposed downstream of the three-way catalyst 62.

  The purge system 70 includes a fuel tank 71, a canister 72, and a purge control valve 73. The canister 72 is configured to capture the evaporated fuel generated in the fuel tank 71 at the connection destination. The canister 72 is provided with activated carbon (not shown) for adsorbing the evaporated fuel inside, and the activated carbon improves the efficiency of adsorption of the evaporated fuel as the temperature decreases, and the adsorbed evaporated fuel desorbs as the temperature increases. It has the property of improving efficiency. The canister 72 is connected to the intake manifold 14 through a purge passage. A purge control valve 73 is interposed in the purge passage. The purge control valve 73 is a configuration for adjusting the purge flow rate, and is a flow rate control valve in which the degree of shielding of the flow path is appropriately changed under the control of the ECU 40A. When the purge control valve 73 communicates with the flow path, the evaporated fuel desorbed in the canister 72 is guided to the intake passage of the intake manifold 14 by the negative pressure of the intake system 10. In this embodiment, the purge flow rate adjusting means is realized by the purge control valve 73.

  The ECU 40A includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output circuit, and the like (not shown). The ECU 40A is mainly configured to control the internal combustion engine 50. In this embodiment, the ECU 40A also controls the VSV 1, the purge control valve 73, the electric throttle 13, and the like. In addition to the VSV 1, the purge control valve 73, and the electric throttle 13, various control objects are connected to the ECU 40A via a drive circuit (not shown). The ECU 40A includes a VSV1 state detection sensor (not shown) for detecting the operating state of the VSV1, a purge control valve 63 state detection sensor (not shown) for detecting the operating state of the purge control valve 73, and an A / F sensor 63. Various sensors such as an oxygen sensor 64, an encoder, an accelerator sensor (not shown) for detecting the state of the accelerator pedal, and a crank angle sensor (not shown) for detecting the rotational speed Ne of the internal combustion engine 50 are connected. ing.

  The ROM is configured to store a program in which various processes executed by the CPU are described. In this embodiment, the ROM circulates the ejector 30 under various conditions in addition to the program for controlling the internal combustion engine 50. The VSV1 control program for controlling the VSV1 so as to change the amount of intake air and to cause the ejector 30 to function or stop functioning (hereinafter also simply referred to as opening or closing VSV1) and the purge control valve 73 are controlled. A purge control program for performing purge control is also stored. However, these programs may be combined together. In this embodiment, the VSV1 control program further specifically blocks the flow path in a fully closed state so as to reduce the amount of intake air flowing through the ejector 30 in accordance with the supply of evaporated fuel. And a purge priority control program for controlling the VSV 1 so that the amount of intake air flowing through the engine is zero. In this embodiment, various control means, detection means, determination means, etc. are realized by the CPU, ROM, RAM (hereinafter also referred to as CPU, etc.) and the above-mentioned various programs. A purge priority control means is realized by the program. In the present embodiment, the negative pressure generator 100 is realized by the VSV 1 and the ejector 30.

  Next, a process performed by the ECU 40A when controlling the VSV 1 to give priority to the supply of the evaporated fuel according to the supply of the evaporated fuel will be described in detail with reference to the flowchart shown in FIG. The ECU 40A controls the VSV 1 by repeatedly executing the processing shown in the flowchart in a very short time based on the purge priority control program stored in the ROM. The CPU executes processing for determining whether or not the ejector 30 is operating (step 11). Whether or not the ejector 30 is in operation can be determined based on, for example, the output signal of the VSV1 state detection sensor. If the determination is negative, the CPU continues to execute the processing shown in this step until an affirmative determination is made in step 11. On the other hand, if the determination is affirmative, the CPU executes processing for determining whether purge control is being performed (step 12Aa).

  Whether or not the purge control is being performed can be determined based on, for example, the output signal of the purge control valve 73 state detection sensor based on whether or not the purge control valve 73 is fully closed and does not block the flow path. However, the present invention is not limited to this, and whether or not the purge control is being performed may be determined based on, for example, an internal process performed by the ECU 40A. In this case, it is possible to determine whether or not the purge control is being performed, for example, based on whether or not a condition for performing the purge control is satisfied. The conditions for performing the purge control specifically include, for example, whether or not the water temperature has reached a predetermined temperature, and whether or not a predetermined time has passed without the purge control being performed. These are performed in order to estimate whether or not there is sufficient evaporated fuel available in the canister 72. However, the present invention is not limited to this, and the conditions for performing the purge control may be appropriate conditions. For example, it may be determined whether or not the air-fuel ratio is stoichiometric.

  If a negative determination is made in step 12Aa, the CPU executes the process shown in step 11 again. On the other hand, if an affirmative determination is made in step 12Aa, the CPU executes a process for closing VSV1 (step 13). That is, as a result of an affirmative determination in step 12Aa, by closing VSV1 in step 13, VSV1 can be closed according to the supply of evaporated fuel. As a result, the negative pressure of the intake system 10 can be quickly increased by the amount by which the intake air flowing through the ejector 30 is reduced, so that priority can be given to the supply of evaporated fuel.

  If VSV1 is realized by a flow rate control valve or the like that can change the degree of shielding of the flow path, instead of closing VSV1 in step 13, for example, at a predetermined degree so as not to completely stop the function of the ejector. It is also possible to control the VSV 1 so as to shield the flow path. Thereby, while giving priority to the supply of the evaporated fuel, the function of the ejector can be maintained to some extent. In this case, a program for controlling the VSV 1 may be stored in the ROM so as to shield the flow path at a predetermined degree as the purge priority control program.

  Further, when VSV1 is realized by a flow rate adjustment valve or the like that can change the degree of shielding of the flow path, instead of closing VSV1 in step 13, for example, purging according to the degree of flow shielding of the purge control valve 73 is performed. It is also possible to control VSV1 so that the degree of channel shielding of VSV1 increases as the degree of channel shielding of control valve 73 decreases. Thereby, priority can be given to the supply of the evaporated fuel so as to be compatible with the function of the ejector to some extent. In this case, a program for controlling the VSV 1 may be stored in the ROM. Further, the degree of shielding of the flow path of the purge control valve 73 can be detected, for example, based on the output signal of the purge control valve 73 state detection sensor. As described above, it is possible to realize the ECU 40A that can prioritize the supply of the evaporated fuel to the internal combustion engine 50 in which the negative pressure generator 100 is used.

  The ECU 40B according to the present embodiment reduces the amount of intake air flowing through the ejector 30 when the purge priority control program is opened so that the purge control valve 73 communicates with the flow path at a predetermined degree α or more. Specifically, according to the first embodiment, except that the program is for controlling the VSV 1 so that the flow amount is shielded in a fully closed state and the amount of intake air flowing through the ejector 30 is made zero. It is the same as ECU 40A. Moreover, each structure with which a vehicle is provided is the same as each structure shown in Example 1 except ECU40A. In this embodiment, the purge priority control means is realized by the CPU and the like and this purge priority control program.

  Next, when the purge control valve 73 is opened to communicate with the flow path at a predetermined degree α or more, the process performed by the ECU 40B in controlling the VSV 1 to give priority to the supply of the evaporated fuel is shown in FIG. This will be described in detail with reference to the flowchart shown in FIG. The flowchart shown in FIG. 4 is the same as the flowchart shown in FIG. 3 except that step 12Aa is changed to step 12Ab. Therefore, in this embodiment, step 12Ab will be described in detail. In step 12Ab, the CPU executes a process of determining whether or not the purge control valve 73 is opened to communicate with the flow path at a predetermined degree α or more. Whether or not it is open can be determined based on, for example, an output signal of the purge control valve 73 state detection sensor. In this step, it is determined whether a large amount of evaporated fuel is going to be used.

  If an affirmative determination is made in step 12Ab, the CPU executes processing for closing VSV1 (step 13). Thereby, priority can be given to supply of evaporative fuel according to the state which is going to utilize a lot of evaporative fuel. If the VSV 1 is realized by a flow rate control valve that can change the degree of shielding of the flow path, the flow path is shielded at a predetermined degree instead of closing the VSV 1 in step 13 as in the first embodiment. The VSV 1 may be controlled as described above. As described above, it is possible to realize the ECU 40B that can prioritize the supply of the evaporated fuel to the internal combustion engine 50 in which the negative pressure generator 100 is used.

  Specifically, the ECU 40C according to this embodiment sets the entire flow path so that the amount of intake air flowing through the ejector 30 is reduced when the purge priority control program further reduces the purge concentration to a predetermined value β or less. The ECU 40A is the same as the ECU 40A according to the second embodiment except that it is configured to have a program for not controlling the VSV 1 so that the amount of intake air that flows through the ejector 30 while being shielded in the closed state is zero. Yes. The purge priority control program included in the ECU 40B according to the second embodiment may be configured to include the above program. Moreover, each structure with which a vehicle is provided is the same as each structure shown in Example 1 except ECU40A. In this embodiment, the purge priority control means is realized by the CPU and the like and this purge priority control program.

  Next, processing performed by the ECU 40C will be described in detail with reference to the flowchart shown in FIG. The flowchart shown in FIG. 5 is the same as the flowchart shown in FIG. 3 except that step 12B is added after step 12Aa. For this reason, in this embodiment, step 12B will be described in detail. If an affirmative determination is made in step 12Aa, the CPU executes a process for detecting the purge concentration and also executes a process for determining whether or not the purge concentration is greater than a predetermined value β (step 12B). Here, when purging is performed, the supplied evaporated fuel is reflected in the air-fuel ratio. From this, the purge amount can be detected by using the output signals of the A / F sensor 63 and the oxygen sensor 64, and further the purge concentration can be calculated. There is a known technique for detecting the purge concentration using the A / F sensor 63 and the oxygen sensor 64, and in this embodiment, the purge concentration detecting method itself may be an appropriate one and will be described here. Is omitted. Further, the present invention is not limited to the A / F sensor 63 and the oxygen sensor 64. For example, an HC sensor (hydrocarbon sensor) may be provided in the purge passage or the intake manifold 14 to detect the purge concentration based on the output signal of the HC sensor. It is.

  If an affirmative determination is made in step 12B, it is determined that the purge concentration is sufficiently high and priority must be given to the supply of evaporated fuel, and the CPU executes the processing shown in step 13. This gives priority to the supply of evaporated fuel. On the other hand, if the determination in step 12B is negative, that is, if the purge concentration is less than or equal to the predetermined value β, the CPU executes the processing shown in step 13 because there is little need to prioritize the supply of evaporated fuel. Instead, the process shown in step 11 is executed. Thereby, it can suppress that the function of the ejector 30 is restrict | limited more than necessary in giving priority to supply of evaporative fuel. As described above, it is possible to give priority to the supply of the evaporated fuel to the internal combustion engine 50 in which the negative pressure generating device 100 is used, and further to suppress the function of the ejector 30 from being restricted more than necessary when giving priority to the supply of the evaporated fuel. A possible ECU 40C can be realized.

  In each of the above embodiments, when the brake negative pressure is not more than a predetermined value, the ejector can be prioritized. In the case where the brake negative pressure becomes equal to or lower than the predetermined value and the braking effectiveness is deteriorated, the sufficient braking effectiveness can be secured by giving priority to the ejector. The brake negative pressure can be obtained by providing the brake device 20 with a negative pressure sensor and receiving the output signal by the ECU 40A. In each of the flowcharts described above, the ECU 40A determines whether the brake negative pressure is equal to or less than a predetermined value when it is determined that the ejector 30 is not operating. When it is determined that the brake negative pressure is equal to or lower than the predetermined value, VSV1 is opened to give priority to the ejector.

  The embodiment described above is a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

2 is a diagram schematically showing a control device for a negative pressure generating device realized by an ECU 40A together with the negative pressure generating device 100. FIG. 3 is a diagram schematically showing an internal configuration of an ejector 30. FIG. It is a figure which shows the process performed by ECU40A with a flowchart. It is a figure which shows the process performed by ECU40B with a flowchart. It is a figure which shows the process performed by ECU40C with a flowchart.

Explanation of symbols

1 VSV
10 Intake System 20 Brake Device 30 Ejector 40 ECU
DESCRIPTION OF SYMBOLS 50 Internal combustion engine 60 Exhaust system 70 Purge system 100 Negative pressure generator

Claims (5)

Negative pressure configured to include an ejector that generates a negative pressure larger than the negative pressure to be taken out from the intake passage of the intake system of the internal combustion engine, and an intake air amount changing means that changes the amount of intake air flowing through the ejector A control device for a negative pressure generator for controlling the generator,
A negative pressure characterized by comprising purge priority control means for controlling the intake air amount changing means so as to reduce the amount of intake air flowing through the ejector in response to the supply of evaporated fuel to the internal combustion engine. Generator control device. Negative pressure configured to include an ejector that generates a negative pressure larger than the negative pressure to be taken out from the intake passage of the intake system of the internal combustion engine, and an intake air amount changing means that changes the amount of intake air flowing through the ejector A control device for a negative pressure generator for controlling the generator,
When the purge flow rate adjusting means for adjusting the supply flow rate of the evaporated fuel is opened so as to communicate with the flow path at a predetermined degree or more, the purge priority control means determines the amount of intake air flowing through the ejector. A control device for a negative pressure generator, wherein the intake air amount changing means is controlled so as to decrease. 3. The control apparatus for a negative pressure generating device according to claim 1, wherein the amount of intake air flowing through the ejector is reduced to be zero. The purge priority means does not control the intake air amount changing means so as to decrease the amount of intake air flowing through the ejector when the concentration of the evaporated fuel is not more than a predetermined value. The control apparatus of the negative pressure generator of any one of 3. The control device for a negative pressure generating device according to any one of claims 1 to 4, wherein when the brake negative pressure is equal to or less than a predetermined value, the ejector is prioritized.

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