JP5070892B2 - Control device for negative pressure generator - Google Patents

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 for controlling the negative pressure generating device when a control system of a throttle valve driven by electronic control is out of order.

  2. Description of the Related Art Conventionally, a brake booster that uses negative pressure generated in an intake passage of an intake system of an internal combustion engine in a vehicle is known. The brake booster generally receives negative pressure from an intake passage (for example, an intake manifold) on the downstream side of the throttle valve, and uses the supplied negative pressure for a function of assisting the driver's pedal effort. On the other hand, an internal combustion engine in which an electric throttle is applied to an intake system is also known. The electric throttle generally has a throttle opener that mechanically opens and fixes the throttle valve at a predetermined opening in preparation for a failure of a throttle valve control system (hereinafter also simply referred to as a throttle control system). This throttle opener enables the vehicle to evacuate when the throttle control system fails.

  However, when the throttle opener is activated, the magnitude of the negative pressure generated on the downstream side of the throttle valve is also reduced. Therefore, if the brake booster negative pressure (hereinafter simply referred to as booster negative pressure) decreases as a result of brake operation when the throttle control system fails, a sufficiently large negative pressure is supplied to the brake booster. As a result, the function of the brake booster is deteriorated by a subsequent brake operation.

  On the other hand, Patent Document 1 proposes an in-vehicle control device shown below. This in-vehicle control device uses an ejector that can supply a brake booster with a negative pressure larger than the negative pressure that is to be taken out from the intake passage of the intake system of the internal combustion engine. The ejector is disposed in a bypass path that bypasses the throttle valve, and generates a larger negative pressure due to the venturi effect. The in-vehicle control device proposed by Patent Document 1 attempts to supply a larger negative pressure to the brake booster using this ejector when the control system of the electric throttle is broken. The evacuation vehicle speed and the booster negative pressure can be maintained at a high level. In addition, for example, Patent Documents 2 to 6 propose techniques that are considered to be related to the present invention.

JP 2005-186708 A JP 2001-50094 A Japanese Laid-Open Patent Publication No. 1-301452 JP 10-291469 A JP 11-182278 A JP 2000-345899 A

  By the way, when the ejector is operated, air also flows through a bypass path that bypasses the throttle valve. Therefore, when the ejector is operated when the throttle control system fails, the intake air amount becomes larger than the intake air amount that should be regulated by the throttle opener, and the torque of the internal combustion engine increases accordingly. . This is inconvenient because it causes an action contrary to this in a situation where the vehicle is desired to be decelerated or stopped during retreat.

  Accordingly, the present invention has been made in view of the above-described problems, and a negative pressure generating device capable of suitably decelerating or stopping a vehicle when an ejector is caused to function to ensure a booster negative pressure during retreat traveling. An object is to provide a control device.

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 the negative pressure generating device, wherein a throttle valve disposed in the intake passage of the intake system is driven by electronic control. When the control system of the throttle valve has failed, and when the vehicle decelerates or stops in a state in which the state changing means causes the ejector to function or is based on the failure, the ejector is by function, stop request priority for controlling said state changing means to suppress the generation of torque due to air flowing through the ejector to the internal combustion engine Characterized in that it comprises a control means.

  According to the present invention, when the vehicle decelerates or stops, the air no longer flows through the bypass path that bypasses the throttle valve, so that it is possible to suppress the generation of torque corresponding to the air in the internal combustion engine. Therefore, according to the present invention, the vehicle can be suitably decelerated or stopped when the ejector is caused to function in order to ensure negative pressure during retreat travel. Even if the function of the ejector is stopped in this way, the ejector can be made to function when the vehicle is stopped, when accelerating during retreating, or when traveling at a constant speed at a relatively high speed. Therefore, according to the present invention, the booster negative pressure can be secured in advance to be sufficiently large in preparation for the brake operation.

  In the present invention, the vehicle may be decelerated or stopped when the vehicle speed is less than a predetermined value. Here, when the vehicle speed is less than the predetermined value, that is, when the vehicle speed is low, it can be considered that the vehicle is decelerated or stopped because it can be regarded as a driving region where the vehicle stop request is high. Therefore, when the vehicle decelerates or stops, specifically, for example, when the vehicle speed is less than a predetermined value as in the present invention, it is preferable. Although the throttle opening cannot be changed by the accelerator pedal when the throttle control system fails, it is generally performed to increase the torque of the internal combustion engine by, for example, advancing the ignition timing by depressing the accelerator pedal. For this reason, when the vehicle decelerates or stops, more specifically, when the vehicle speed is less than a predetermined value, it is preferable that the accelerator pedal is not further depressed.

  In the present invention, the vehicle may be decelerated or stopped when a brake operation is being performed. More specifically, for example, when the brake operation is being performed, it is also preferable to control the state changing means so as to stop the function of the ejector.

  ADVANTAGE OF THE INVENTION According to this invention, when making an ejector function in order to ensure a booster negative pressure at the time of evacuation driving | running, the control apparatus of the negative pressure generator which can decelerate or stop a vehicle 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, 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 air amount and outputs a signal corresponding to the intake air amount.

  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. A return spring (not shown) that functions as a throttle opener is connected to the throttle valve 13a. 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 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 a throttle opening degree sensor (not shown) built in the electric throttle 13. 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 at a predetermined boost ratio with respect to the pedal depression force, and a negative pressure chamber (not shown) partitioned on the master cylinder 23 side through the ejector 30 is provided inside. The intake manifold 14 is connected to the intake passage. 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 device 20 is provided with a brake SW 24 that detects depression of the brake pedal 21. 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 in the air cleaner 11 and the air hose 5a, and the outflow port 31b is connected to the intake passage of the intake manifold 14 by the 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 air flow meter 12 and 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 routed from the intake passage of the intake manifold 14 through 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. 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, thereby generating a large negative pressure in the negative pressure extraction portion 32c due to the venturi effect. 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 40A 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 40A is mainly configured to control the internal combustion engine 50, and also controls the VSV 1 and the electric throttle 13 in this embodiment. In addition to the VSV 1 and the electric throttle 13, various control objects are connected to the ECU 40A. The ECU 40A detects the throttle opening sensor, the brake SW 24, the vehicle speed sensor 71 for detecting the vehicle speed, the accelerator sensor 72 for detecting the accelerator opening (depression amount), and the water temperature of the internal combustion engine 50. Various sensors such as a water temperature sensor 73 for detecting the rotational speed NE and a crank angle sensor 74 for detecting the rotational speed NE of the internal combustion engine 50 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 program for controlling the electric throttle 13 and various conditions. Originally, a VSV1 control program for controlling the VSV1 so as to cause the ejector 30 to function or stop functioning (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. Note that these programs may be combined together.

  The electric throttle 13 control program has a retreat travel control program. The evacuation travel control program is created so as to determine whether or not a failure (failure) has occurred in the throttle control system, and to cut off energization to the electric motor 13d when it is determined that a failure has occurred. Has been. For this reason, when a failure occurs in the throttle control system, the return spring can exert a spring force, and the throttle valve 13a is opened to a predetermined opening (for example, 7 to 8 degrees) by the return spring. The valve is fixed. As a result, a certain amount of intake air is allowed in the electric throttle 13, so that the vehicle can be retreated even if a failure occurs in the throttle control system. The failure of the throttle control system includes, for example, a failure due to an abnormality in the throttle opening sensor, an abnormality in the control circuit, an abnormality in the electric motor 13d, and the like.

  The VSV1 control program has a specific booster negative pressure securing control program for opening the VSV1 when it is determined that the throttle control system has failed during the warm period based on the retreat travel control program. ing. As a result, the booster negative pressure can be secured at a sufficient level during the retreat travel. Further, in this embodiment, the VSV1 control program is requested to stop the VSV1 when the VSV1 is opened based on the specific booster negative pressure ensuring control program or when the vehicle decelerates or stops in the open state. It has a priority control program. In this embodiment, the stop request priority control program sets when the vehicle decelerates or stops when the vehicle speed is smaller than the predetermined value A. Therefore, the VSV1 control program is also configured to include a vehicle speed determination program for determining whether or not the vehicle speed is equal to or lower than the predetermined value A. 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 stop request priority control means is realized by the microcomputer and the stop request priority control program. Yes. In the present embodiment, a control device for the negative pressure generating device is realized by the ECU 40A.

  Next, processing performed by the ECU 40A will be described in detail with reference to the flowchart shown in FIG. The ECU 40A controls the negative pressure generating device by repeatedly executing the processing shown in the flowchart in a very short time by the CPU based on the above-described various programs stored in the ROM. The CPU executes a process of determining whether or not the water temperature has exceeded a predetermined value α (for example, 75 ° C.) (step S11). That is, it is determined in this step whether or not it is warm. If the determination is negative, since it is cold, the process proceeds to step S14, and the CPU executes a process for opening VSV1 (step S14).

  On the other hand, if an affirmative determination is made in step S11, it is determined that it is warm, and the CPU executes a process of determining whether or not the throttle control system is out of order (electric thro-fail) (step S12). If the determination is negative, the CPU executes a process for closing the VSV 1 since it is a warm time that does not require any special process (step S15). On the other hand, if an affirmative determination is made in step S12, the CPU executes a process of determining whether or not the vehicle speed is equal to or higher than a predetermined value A (step S13A). That is, in this step, it is determined whether or not the vehicle speed is low, in other words, whether or not the vehicle is in a driving region where the vehicle deceleration request is high. If the determination is affirmative, the CPU executes a process for opening VSV1 (step S14). As a result, the booster negative pressure can be secured at a sufficient level during retreat travel.

On the other hand, if a negative determination is made in step S13A, the CPU executes a process for closing VSV1 (step S15). As a result, it is possible to suppress the generation of torque in the internal combustion engine 50 due to the air flowing through the bypass passage B in an operation region where the vehicle deceleration request is high, so that the vehicle can be suitably decelerated or stopped. become.

In addition, following the negative determination in step S13A, it may be further determined based on the output of the accelerator sensor 72 whether or not the accelerator pedal is depressed. If the determination is negative, the process may proceed to step S15. In this case, it can be said that the stop request is in a higher operating state, which is more preferable than the case where the determination is not performed. For example, an accelerator pedal depression determination program for performing such determination is provided as a part of the VSV1 control program, and a stop request priority control program is created so that VSV1 is closed when the accelerator pedal is not depressed further. This can be achieved. Thus, when the ejector 30 to function to ensure the booster negative pressure during emergency driving, suitably it can be realized ECU 40 A which can be decelerated or stopped vehicle.

The ECU 40 B according to the present embodiment is configured such that the stop request priority control program stored in the ROM is different, and the VSV1 control program is accompanied by a brake operation determination program. Except for this point, it is the same as the ECU 40 A according to the first embodiment. Each configuration included in the vehicle except the ECU 40 A is changed to ECU 40 B, it has become the same as each configuration shown in FIG. In this embodiment, in the stop request priority control program, the time when the vehicle decelerates or stops is set when the brake operation is performed. For this reason, the VSV1 control program has a brake operation determination program for determining whether or not a brake operation is being performed based on the output of the brake SW24. 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 stop request priority control means is realized by the microcomputer and the above-described stop request priority control program. Has been. In the present embodiment, a control device for the negative pressure generating device is realized by the ECU 40B.

Next, processing performed by the ECU 40 B 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 described in the first embodiment except that step S13A is changed to step S13B. Therefore, in this embodiment, step S13B will be described in detail. Following the affirmative determination in step S12, the CPU executes a process of determining whether or not the brake operation is not performed (brake OFF) (step S13B). If the determination is affirmative, the CPU executes a process for opening VSV1 (step S14). As a result, the booster negative pressure can be secured at a sufficient level during retreat travel.

On the other hand, if a negative determination is made in step S13B, it is determined that a brake operation is being performed, and the CPU executes a process for closing VSV1 (step S15). Thereby, since it can suppress that the torque for the part resulting from the air which distribute | circulates the bypass path B generate | occur | produces in the internal combustion engine 50, it becomes possible to decelerate or stop a vehicle suitably. As described above, when the ejector 30 is caused to function in order to ensure the booster negative pressure during the retreat travel, the ECU 40 B that can preferably decelerate or stop the vehicle can be realized.

  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 40A together with a negative pressure generator 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.

Explanation of symbols

1 VSV
10 Intake System 13 Electric Throttle 20 Brake Device 22 Brake Booster 30 Ejector 40 ECU
50 Internal combustion engine 100 Negative pressure generator

Claims (3)

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,
The throttle valve disposed in the intake passage of the intake system is driven by electronic control, and when the control system of the throttle valve is out of order, the state changing means further functions the ejector based on the failure. The function of the ejector is stopped when the vehicle decelerates or stops in a state of being caused to stop, thereby suppressing generation of torque due to air flowing into the internal combustion engine via the ejector. A control apparatus for a negative pressure generator, comprising stop request priority control means for controlling state change means. 2. The negative pressure generator control device according to claim 1, wherein the vehicle is decelerated or stopped when the vehicle speed is less than a predetermined value. 2. The control device for a negative pressure generating device according to claim 1, wherein the vehicle is decelerated or stopped when a brake operation is being performed.

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