JP2008267245A - Control device for negative pressure generation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a negative pressure generation device more suitably making an ejector work, when making the ejector work according to a fuel cut control. <P>SOLUTION: An ECU 40 controls a negative pressure generation device including: the ejector 30 generating negative pressure larger than negative pressure to be taken from an intake manifold 14 of an internal combustion engine 50 mounted on the vehicle; and a VSV1 making or stopping making the ejector 30 work. The ECU 40 further includes a specific prohibition control means prohibiting the control of the VSV1 to make the ejector 30 work at the same time as a fuel cut control when the VSV1 is controlled to make the ejector 30 work according to the fuel cut control executed in the internal combustion engine 50. <P>COPYRIGHT: (C)2009,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 causes an ejector to function according to fuel cut control.

  Conventionally, a negative pressure such as a brake booster is larger than a negative pressure (hereinafter simply referred to as an intake pipe negative pressure) to be taken out from an intake passage (for example, an intake manifold or a surge tank) of an intake system of an internal combustion engine in a vehicle. An ejector is used to supply the pressure actuator. With regard to this ejector, for example, Patent Document 1 proposes a technique that is considered to be related to the present invention.

JP 2006-118495 A

  In recent years, interest in environmental issues such as global warming and air pollution has increased, and in vehicles, reducing emissions of hydrocarbons such as hydrocarbon HC contained in exhaust gas is an important issue. It has become. For this purpose, it is one of the effective measures to quickly raise the temperature of the catalyst disposed in the exhaust system of the internal combustion engine to the reaction temperature. Therefore, after the internal combustion engine is started, the catalyst is activated. In general, control for retarding the ignition timing of the internal combustion engine is generally performed. At the same time, in order to compensate for the decrease in torque, the throttle valve is also controlled so as to open the intake passage to increase the intake flow rate (hereinafter, these controls are simply referred to as catalyst warm-up control). By performing catalyst warm-up control, more air-fuel mixture can be combusted at a time closer to the exhaust stroke, so that exhaust gas can reach the catalyst at a higher temperature. The temperature can be raised to the reaction temperature.

  However, when the intake passage is largely opened by the throttle valve as described above, the negative pressure generated in the intake system of the internal combustion engine is reduced. In this case, since the brake booster extracts the negative pressure from the intake system of the internal combustion engine, the function of assisting the brake operation becomes insufficient, and as a result, the operation burden on the driver increases. On the other hand, when the catalyst warm-up control is performed, a larger negative pressure can be supplied to the brake booster by using the ejector. In this case, since the intake passage is opened relatively large, even if the ejector functions, the degree of fluctuation of the intake air amount relatively decreases. For this reason, idling does not become unstable even if the ejector is made to function.

  On the other hand, when the water temperature of the internal combustion engine exceeds a predetermined value and the catalyst is activated, the catalyst warm-up control becomes unnecessary. In this case, the throttle valve is throttled to an appropriate opening in order to reduce the target rotational speed during idling for the purpose of improving fuel efficiency. However, if the ejector is functioned in this case, the air-fuel ratio is affected, and it becomes difficult to control the idle speed to the target speed. As a result, idling may become unstable. The simplest measure for this is to prevent the ejector from functioning. However, if the ejector is not allowed to function, the following problems occur.

  Since the ejector has a structure that generates a large negative pressure by the venturi effect, the passage corresponding to a portion that generates a large negative pressure in the ejector is narrowed down. When the ejector is not functioned for a long time, the intake air does not flow, so that this passage is likely to be clogged. The cause of the clogging is, for example, that moisture contained in the intake air condenses and accumulates in this passage and freezes in the winter, or intake air containing oil enters the ejector and adheres to the wall surface of this passage. As a result of the oil being combined with the dust on the wall surface, it is generated in a deposit that gradually closes the passage. Such clogging may occur not only in the ejector itself, but also in the entire flow path of the negative pressure generating device including the ejector.

  On the other hand, if the ejector is made to function when fuel injection is not performed in the combustion cycle of the internal combustion engine, the above-mentioned clogging can be suppressed without adversely affecting idling. In order to make the ejector function in this way, specifically, it is preferable to make the ejector function according to, for example, fuel cut control performed in an internal combustion engine. However, in this case, although the occurrence of clogging described above can be suppressed, it is still from the viewpoint of obtaining a higher cleaning effect in suppressing the occurrence of clogging, or from the viewpoint of dealing with the case where clogging is promoted instead. It turns out that there is room for improvement.

  Therefore, the present invention has been made in view of the above-described problems, and provides a control device for a negative pressure generating device that can cause the ejector to function more suitably when the ejector functions according to fuel cut control. With the goal.

  In order to solve the above 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 provided in a vehicle, and a state change that causes the ejector to function or stop functioning. A negative pressure generating device for controlling a negative pressure generating device configured to include the means, wherein the ejector is made to function in accordance with fuel cut control performed in the internal combustion engine. It is characterized by comprising specific prohibition control means for prohibiting the state change means from being controlled to function the ejector simultaneously with the fuel cut control when the state change means is controlled.

  Here, the ejector is generally disposed in a bypass path that bypasses the throttle valve, and the intake air is the pressure difference between the upstream pressure of the throttle valve and the downstream pressure (intake pipe negative pressure) (hereinafter simply referred to as the front and rear of the ejector). Distributes the ejector according to the differential pressure). Therefore, it can be said that when the ejector is operated in a state where the ejector front-rear differential pressure is large, a greater momentum is given to the intake air flowing through the ejector, and thus a higher cleaning effect can be obtained.

  On the other hand, fuel cut control is performed when the accelerator pedal that was being depressed is released, but at this time there is a time delay between when the throttle valve is closed and when the intake pipe negative pressure further increases. . Therefore, when the ejector functions in a state where the ejector front-rear differential pressure is larger, it is possible to cause the ejector to function in a state where the ejector front-rear differential pressure is larger if the state change means is not controlled simultaneously according to the fuel cut control. As a result, a higher cleaning effect can be obtained.

  Further, when the throttle valve is opened during vehicle acceleration, the pressure difference between the upstream side and the downstream side of the throttle valve may be almost eliminated. At this time, a phenomenon may occur in which oil mist containing oil flows backward from the internal combustion engine to the intake passage on the upstream side of the throttle valve via the PCV pipe or the intake passage. For this reason, when the state changing means is controlled simultaneously in accordance with the fuel cut control, there is a risk that the oil mist that has flowed back will flow into the negative pressure generator, and as a result, the generation of deposits is promoted. On the other hand, the occurrence of clogging of the negative pressure generator may be promoted.

  The present invention has been made in view of the above points, and according to the present invention, it is possible to obtain a higher cleaning effect and cope with a case where the occurrence of clogging is promoted. Accordingly, when the ejector is caused to function, the ejector can be caused to function more suitably. In the case of controlling the state changing means in accordance with the fuel cut control, even when the state of the state changing means is not controlled at the same time as the fuel cut control, even if the mode of prohibition is not adopted in the form of control (specifically, In this case, the specific prohibition control means of the present invention can be said to be realized in the form included in advance in the control means for controlling the state change means. Are also included in the practice of the present invention.

  Further, in the present invention, even if the specific prohibition control unit prohibits the state changing unit from controlling the ejector to function until a predetermined time elapses after the fuel cut control is started. Good. Specifically, for example, it is preferable to prohibit until a predetermined time elapses as in the present invention.

  In addition, from the viewpoint of obtaining a higher cleaning effect, the predetermined time may be appropriately set to a time during which the intake pipe negative pressure increases more than when the state changing means is controlled simultaneously according to the fuel cut control. On the other hand, from the viewpoint of suppressing the occurrence of clogging in the negative pressure generator, it is preferable to set the time required for the oil mist that has flowed back until it is sucked again into the intake passage on the downstream side of the throttle valve. The predetermined time in this case can be determined by, for example, an experiment or the like by previously grasping the time until the oil mist is sucked into the intake passage on the downstream side of the throttle valve according to the operating state of the internal combustion engine.

  The present invention may further include a predetermined time changing means for changing the predetermined time according to the operating state of the internal combustion engine or the vehicle immediately before the fuel cut control is performed. Here, the amount of oil mist that flows back to the intake passage upstream of the throttle valve varies depending on the operating state (for example, the rotational speed) of the internal combustion engine immediately before the fuel cut control is performed. In this regard, when the predetermined time is set to a constant value as described above, it is possible to more reliably suppress the occurrence of clogging, but the control of the state changing means is prohibited even when unnecessary. As a result, the cleaning time is shortened, and the cleaning effect may be reduced as a whole. On the other hand, according to the present invention, it is possible to obtain an optimum effect on the balance.

  Also, if the operating state of the internal combustion engine immediately before fuel cut control continues to be a high load and high speed, or if the driving state of the vehicle continues to be in an accelerated state, the oil mist In the case where a large amount of backflow occurs, according to the present invention, the occurrence of clogging can be favorably suppressed by changing the predetermined time significantly longer.

  According to the present invention, the specific prohibition control means is controlled so that the state changing means causes the ejector to function according to the operating state of the internal combustion engine or the vehicle immediately before the fuel cut control is performed. It may be prohibited. Also, as described above, when the operation state of the internal combustion engine immediately before the fuel cut control is continued to be high load and high speed, or when the vehicle operation state is continuously accelerated. Since a large amount of backflow of oil mist is generated, in such a case, it is also preferable to prohibit the state changing means from being controlled to function the ejector as in the present invention.

  In the present invention, the specific prohibition control means is controlled so that the state change means causes the ejector to function when snow is attached to the vehicle and the temperature of the intake air is lower than a predetermined value. It may be prohibited. Here, in the ejector, the temperature of the intake air decreases when the intake air flows through a passage that is narrowed down to generate a larger negative pressure. For this reason, when the snowmelt water having a low temperature is included in the intake air, there is a high risk of freezing in the negative pressure generating device. According to the present invention, the negative pressure generating device is blocked due to freezing. It can be prevented or suppressed. Whether snow is attached or not can be easily detected, for example, by checking whether or not the de-icer switch (glass heat wire switch) is ON, and a sensor that detects the temperature of the glass or body. It may be possible to detect whether the temperature is 0 ° C. or not.

  ADVANTAGE OF THE INVENTION According to this invention, when making an ejector function according to fuel cut control, the control apparatus of the negative pressure generator which can make an ejector function more suitably can be provided.

  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 realized by an ECU (Electronic Control Unit) 40 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 air amount and outputs a signal corresponding to the intake air amount. The air flow meter 12 incorporates an intake air temperature sensor (not shown), and the intake air temperature (hereinafter simply referred to as intake air temperature) is detected by the ECU 40 based on the output of the intake air temperature sensor.

  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 amount of intake air supplied to the internal combustion engine 50 by changing the opening. The throttle body 13b is composed of a cylindrical member in which an intake passage is formed, and 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 40, 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 40 based on an output signal from a throttle opening degree sensor (not shown) built in the electric throttle 13.

  In addition to the throttle-by-wire system in which the throttle valve 13a such as the electric throttle 13 is driven by an actuator, the throttle mechanism is linked to an accelerator pedal (not shown) via a wire or the like instead of the electric throttle 13, and the throttle valve A mechanical throttle mechanism in which the opening degree of 13a is changed may be applied. 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 intake system 10 is provided with a PCV pipe 16 that communicates the internal combustion engine 50 with an intake passage on the upstream side of the throttle valve 13a.

  The brake device 20 includes a brake pedal 21, a brake booster (negative pressure operating device) 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 generates a negative pressure that is larger than the negative pressure to be taken out from the intake system 10, more specifically, the intake manifold 14 that is downstream of the throttle valve 13a (hereinafter simply referred to as intake manifold negative pressure). This is a configuration for supplying 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. Further, the negative pressure filled in the negative pressure chamber of the brake booster 22 is hereinafter simply referred to as booster negative pressure.

  A VSV (vacuum switching valve) 1 is interposed in the air hose 5a. The VSV 1 is a configuration for communicating and blocking the bypass path B based on the control of the ECU 40, and in this 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. The VSV 1 is configured to cause the ejector 30 to function or stop functioning by communicating and blocking the bypass path B. In the present embodiment, the state 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 check 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. In this embodiment, the negative pressure generating device 100 is realized by including the VSV 1 and the ejector 30. More specifically, the negative pressure generating device 100 has air hoses 5a, 5b and 5c and a check valve 34. Configured.

  The ECU 40 is a microcomputer (hereinafter simply referred to as a microcomputer) that includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory) (not shown). And an input / output circuit. The ECU 40 is mainly configured to control the internal combustion engine 50. In this embodiment, the ECU 40 also controls the VSV 1, the electric throttle 13, and the like. In addition to the VSV 1 and the electric throttle 13, various control objects are connected to the ECU 40. The ECU 40 includes an air flow meter 12, a throttle opening sensor, a water temperature sensor 71 for detecting the water temperature of the internal combustion engine 50, a crank angle sensor 72 for detecting the rotational speed NE of the internal combustion engine 50, and not shown. Various sensors and switches such as de-icer switches are connected.

  The ROM is configured to store a program in which various processes executed by the CPU are described. In this embodiment, in addition to the program for controlling the internal combustion engine 50, the ejector 30 functions under various conditions. Alternatively, a VSV1 control program for controlling the VSV1 so as to stop the function (hereinafter simply referred to as opening or closing the VSV1) is also stored. The VSV 1 is basically opened by the VSV 1 control program when it is cold (for example, 75 ° C. or less) and closed when it is warm. The fuel cut (hereinafter simply referred to as F / C) control program is configured as a part of the program for controlling the internal combustion engine 50, and the F / C control program has a certain rotational speed NE. It is created to perform F / C when the accelerator pedal is released in a high state. Moreover, these programs may be combined together.

  The VSV1 control program includes a cleaning control program that opens VSV1 when F / C control is started in accordance with F / C control performed in the internal combustion engine. Further, in this embodiment, the VSV1 control program is based on the cleaning control program described above, and when the VSV1 is opened according to the F / C control, the VSV1 is prohibited from being opened simultaneously with the F / C control. It has a control program. In the present embodiment, specifically, the specific prohibition control program is created so as to prohibit the VSV 1 from being opened until the predetermined time T elapses after the F / C control is started.

  The specific prohibition control program is created so as to prohibit the VSV 1 from being opened according to the operating state of the internal combustion engine 50 or the vehicle immediately before the F / C control is performed. Specifically, when the operation state of the internal combustion engine 50 immediately before the F / C control is performed is a high load and a high rotation speed, the operation state of the vehicle immediately before the F / C control is performed is It is created so as to completely prohibit the VSV 1 from being opened while the F / C control is being performed when the acceleration state continues.

  In addition, this specific prohibition control program further determines that VSV1 is set when the vehicle is covered with snow and the intake air temperature is lower than a predetermined value (temperature at which the ejector 30 reduces the intake air temperature to 0 ° C. or lower). In the present embodiment, specifically, in a state where snow is attached to the vehicle, the F / C control is performed while the de-icer switch is turned on. , VSV1 is completely prohibited from being opened. At the same time, the prohibition is performed only when the intake air temperature is lower than the predetermined value in order to prevent a situation in which the VSV 1 is not opened according to the F / C control due to forgetting to turn off the de-icer switch.

  On the other hand, the VSV1 control program includes a predetermined time change program that changes the predetermined time T1 in accordance with the operating state of the internal combustion engine 50 or the vehicle immediately before the F / C control is performed. In the present embodiment, the predetermined time changing program specifically detects the rotational speed NE immediately before the F / C control is performed, and the predetermined time T is defined in advance according to the rotational speed NE. The corresponding predetermined time T is read from the map data, and the predetermined time T is changed to the newly read predetermined time T. For this reason, in this embodiment, the predetermined time map data is also stored in the ROM. In this embodiment, various control means, detection means, determination means, and the like are realized by the microcomputer and the above-described various programs. In particular, the specific prohibition control means between the microcomputer and the specific prohibition control program is the microcomputer and the predetermined time. The changing program implements a predetermined time changing means.

  Next, processing performed by the ECU 40 will be described in detail with reference to the flowchart shown in FIG. The ECU 40 opens the VSV 1 simultaneously with the F / C control according to the F / C control by repeatedly executing the processing shown in the flowchart in a very short time based on the above-described various programs stored in the ROM. Prohibit that. In addition, this flowchart is performed at the time of warm in a present Example. The CPU executes processing for determining whether or not F / C deceleration is in progress (step S11). If the determination is negative, it is a warm time that does not require any special processing, so the CPU executes processing for closing VSV 1 (step S15). On the other hand, if an affirmative determination is made in step S11, the CPU executes a process of reading the operating condition of VSV1 (step S12).

  Here, in this embodiment, the microcomputer stores the history of the rotational speed NE and load of the internal combustion engine 50, the throttle opening degree, and the like. In step S12, the rotational speed immediately before the F / C control is performed based on this history. NE is read, and the operating state of the internal combustion engine 50 (here, the rotational speed NE and the load) and the vehicle operating state (here, the throttle opening) immediately before the F / C control is performed can determine these continuation states. Is read as follows. At the same time, in this step, the ON / OFF state of the de-icer switch is detected and the intake air temperature is detected. At the same time, in this step, a predetermined time T corresponding to the rotational speed NE immediately before the F / C control is performed is read.

  Subsequently, the CPU executes a process of determining whether or not the VSV 1 should not be prohibited from being opened (step S13). Specifically, in this step, whether or not the operating state of the internal combustion engine 50 has continued to be high load and high speed, whether or not the driving state of the vehicle has been continuously accelerated, It is determined whether the de-icer switch is ON and the intake air temperature is not lower than a predetermined value. If any one of these determinations is negative, the process proceeds to step S15. As a result, it is possible to completely inhibit the VSV 1 from being opened simultaneously in accordance with the F / C control, and the VSV 1 from being opened while the F / C control is being performed. It can suppress that generation | occurrence | production of is promoted.

  It should be noted that the duration of the continuous state, the rotational speed NE and the magnitude of the load corresponding to a high load and a high rotational speed, and the magnitude of the throttle opening corresponding to the acceleration state are the degree of occurrence of backflow of oil mist. Can be determined as appropriate by grasping the above by an experiment or the like. Further, the rotational speed NE and the load corresponding to the high load and the high rotational speed can be prepared by, for example, storing the rotational speed NE and load map data in the ROM and defining the map data in advance as an area. Further, if a negative determination is made in step S13, step S12 may be skipped in a routine subsequent to the next time until a negative determination is made in step S11.

  If all the determinations described above are affirmative determinations, the CPU further executes a process of determining whether or not the predetermined time T has elapsed in step S13. If a negative determination is made, the CPU proceeds to step S15, further returns, and returns to step S11. As a result, when the predetermined time T has elapsed in the routine after the next time, an affirmative determination is made in step S13, and at this time, the CPU executes a process for opening VSV1 (step S14). As a result, the VSV 1 can be prohibited from being opened simultaneously in accordance with the F / C control, and the VSV 1 can be prevented from being opened until the predetermined time T elapses. It is possible to suitably suppress the occurrence of clogging in terms of the balance with the cleaning effect.

  In the present embodiment, the case where the predetermined time T is changed according to the rotational speed NE is shown, but the predetermined time T may be a fixed value. The predetermined time T in this case is determined in advance according to the operating state of the internal combustion engine 50, for example, the longest time until the oil mist that has flowed back is sucked into the intake passage on the downstream side of the throttle valve 13a. It is preferable to determine by grasping. In this case, the predetermined time changing program and the predetermined time map data are not required. The predetermined time T increases the momentum of the intake air flowing through the ejector 30, and from the viewpoint of obtaining a higher cleaning effect, the intake pipe negative pressure increases more than when the VSV 1 is simultaneously controlled according to the F / C control. It may be set as appropriate for the time to perform. In addition, the predetermined time T in this case may be a fixed value, and may be appropriately defined by map data according to the operating state of the internal combustion engine 50, for example. By the above, when making the ejector 30 function according to F / C control, ECU40 which can make the ejector 30 function more suitably is realizable.

  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 an ECU 40 together with a 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 ECU40 with a flowchart.

Explanation of symbols

1 VSV
10 Intake System 13 Electric Throttle 14 Exhaust Manifold 16 PCV Piping 20 Brake Device 22 Brake Booster 30 Ejector 40 ECU
DESCRIPTION OF SYMBOLS 50 Internal combustion engine 71 Water temperature sensor 72 Crank angle sensor 100 Negative pressure generator

Claims (5)

A negative pressure configured to include 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 provided in the vehicle, and a state changing unit that causes the ejector to function or stop functioning. A control device for a negative pressure generator for controlling the generator,
When the state changing means is controlled to cause the ejector to function in accordance with fuel cut control performed in the internal combustion engine, the state changing means is controlled to cause the ejector to function simultaneously with the fuel cut control. A control device for a negative pressure generating device, comprising specific prohibition control means for prohibiting the operation. The specific prohibition control unit prohibits the state change unit from being controlled to function the ejector until a predetermined time elapses after the fuel cut control is started. Item 2. A control device for a negative pressure generator according to Item 1. The negative pressure generator according to claim 2, further comprising a predetermined time changing unit that changes the predetermined time according to an operating state of the internal combustion engine or the vehicle immediately before the fuel cut control is performed. Control device. The specific prohibition control means prohibits the state changing means from being controlled to cause the ejector to function in accordance with the operating state of the internal combustion engine or the vehicle immediately before the fuel cut control is performed. The control device for a negative pressure generator according to claim 1, wherein: The specific prohibition control means prohibits the state change means from being controlled to cause the ejector to function when snow is attached to the vehicle and the temperature of the intake air is lower than a predetermined value. The control device for a negative pressure generator according to claim 1, wherein:

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