JP2007327353A - Control device for negative pressure generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a negative pressure generator capable of suitably securing a negative pressure by using an ejector and capable of solving a problem of response delay at a time of transition for securing a negative pressure. <P>SOLUTION: This device comprises the ejector 30 generating a negative pressure greater than that to be taken out of an intake manifold 14 and a VSV 1 functioning the ejector 30 or stopping function of the ejector 30. An ECU 40 controls a negative pressure generation device 100 arranged in a channel independent from an electric throttle adjusting intake air quantity at a time of idling of an internal combustion engine 50, and is provided with a priority control means controlling the VSV 1 with priority over control of an electric throttle 13 when adjusting intake air quantity to intake air quantity demanded by the internal combustion engine 50 during idling. <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. With regard to this ejector, for example, Patent Document 1 proposes a negative pressure generating device provided with an idler control valve (hereinafter also simply referred to as ISCV) and an idling pipeline that bypasses the throttle valve. Patent Document 2 proposes a negative pressure generator having a structure in which an ejector and an ISCV are integrated. Further, Patent Document 3 proposes a vehicle negative pressure supply device that includes an ejector throttle valve that is assembled to a support shaft that rotates integrally with a throttle valve so as to be integrally rotatable, in a bypass passage in which the ejector is disposed. ing.

JP 2004-285838 A JP 2004-299567 A JP 2005-201196 A

  Here, in the negative pressure generating device proposed in Patent Documents 1 and 2, the ejector generates a negative pressure in accordance with the magnitude of the intake flow rate adjusted by the ISCV. For this reason, if an attempt is made to secure a negative pressure as large as possible with an ejector as necessary, it is considered that the idle rotational speed will inevitably increase due to the structure. In this case, since the negative pressure to be taken out from the intake system of the internal combustion engine becomes small, it is impossible to generate a large negative pressure by the ejector. That is, these negative pressure generators have a structure in which the ejector cannot be fully utilized when the negative pressure to be taken out from the intake system of the internal combustion engine is large. In this regard, the vehicle negative pressure supply device proposed in Patent Document 3 cannot also control the throttle valve and the ejector throttle valve independently. Therefore, when the negative pressure to be taken out from the intake system of the internal combustion engine is large as well. It is considered that the ejector cannot be fully utilized. On the other hand, since the ejector is not supplied with a large amount of negative pressure per unit time, there is a possibility that the negative pressure cannot be sufficiently secured when it is attempted to secure the negative pressure as necessary.

  Therefore, the present invention has been made in view of the above problems, and it is possible to suitably secure a negative pressure by using an ejector. Further, it is possible to improve the problem of a delay in responsiveness at the time of shifting to securing a negative pressure. An object of the present invention is to provide a control device for a negative pressure generator.

  In order to solve the above-described problems, the present invention provides an ejector that generates a negative pressure larger than a negative pressure to be taken out from an intake passage of an intake system of an internal combustion engine, and a state changing unit that causes the ejector to function or stop functioning. And a negative pressure generator control device for controlling a negative pressure generator disposed in a path independent of the idle flow rate adjusting means for adjusting the intake flow rate during idling of the internal combustion engine. In addition, when adjusting the intake flow rate to the intake flow rate required by the internal combustion engine during idling, priority control means for controlling the state change means is provided in preference to the idle flow rate adjustment means.

  According to the present invention, the negative pressure generating device is arranged in a path independent of the idle flow rate adjusting means, and the negative pressure generating device can be controlled independently of the idle flow rate adjusting means. When the pressure is low, that is, when the negative pressure to be taken out from the intake system of the internal combustion engine is high, the ejector can be used to ensure the negative pressure. In addition to this point, according to the present invention, since the state changing unit is controlled in preference to the idle flow rate adjusting unit, the state changing unit is configured to reduce the degree of shielding of the flow path while adopting such a structure. By realizing it with a controllable flow rate control valve or the like, it is possible to keep the ejector functioning at all times. Therefore, according to the present invention, the problem of delay in response at the time of shifting to securing negative pressure, which is a problem when the ejector is caused to function as necessary, can be improved.

  In the present invention, the priority control means may further cause the ejector to function when an intake air flow required by the internal combustion engine is larger than an intake air flow that increases when the state changing means is controlled. The state changing means may be controlled. Here, for example, when the state changing means is a valve having a structure that switches the flow path to full open and full close, if the valve is fully opened when the target value of the idling speed is low, the intake flow rate becomes the internal combustion flow rate. There is a possibility that the intake flow rate becomes excessively higher than that required by the engine and the idling speed increases. On the other hand, according to the present invention, it is possible to increase the opportunity for the ejector to function without adversely affecting the maintenance of the idling speed. As a result, the negative pressure can be secured in advance, so that the problem of delay in response at the time of shifting to securing the negative pressure, which is a problem when the ejector is made to function as necessary, can be improved.

  Further, according to the present invention, an intake air flow rate required by the internal combustion engine is an intake air flow rate indicated by a predetermined control amount that does not require responsiveness among control amounts for controlling the idle flow rate adjusting means. Also good. Here, since the ejector has a throttle structure, the intake air flow rate gradually increases when the ejector functions. In other words, the ejector has a property of low responsiveness with respect to an increase in the intake flow rate. Therefore, the intake flow rate indicated by the control amount that requires responsiveness, specifically, for example, the control amount related to feedback control performed to suppress fluctuations in the idle speed, can be quickly handled. The idle speed can be suitably controlled by adjusting the flow rate adjusting means. According to the present invention in view of such a point, it is possible to increase opportunities for the ejector to function without impairing the controllability of the idle rotation speed. As a result, the negative pressure can be secured in advance, so that the problem of delay in response at the time of shifting to securing the negative pressure, which is a problem when the ejector is made to function as necessary, can be improved.

  According to the present invention, there is provided a control device for a negative pressure generating device that can suitably secure a negative pressure by using an ejector, and that can improve the problem of delay in response at the time of shifting to the securing of the negative pressure. it can.

  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 a 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. Further, the electric throttle 13 has a configuration for adjusting the intake flow rate in order to control the idle rotation speed. In this embodiment, the electric throttle 13 implements an idle flow rate adjusting means. 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 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 13 a is detected by the ECU 40 based on an output signal from an encoder (not shown) built 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. In this case, for example, a bypass path is formed with respect to the throttle valve 13a, and the idle speed can be controlled by interposing the ISCV in the bypass path. Therefore, this ISCV can be used as an idle flow rate adjusting means. 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 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 40, and a 2-position 2-port normally closed solenoid valve is employed in this embodiment. 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 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 internal combustion engine 50 is provided with an air conditioner compressor 55. The air conditioner compressor 55 has a drive shaft pulley connected to an output shaft pulley of the internal combustion engine 50 via a belt. In addition to an air conditioner compressor 55 as an auxiliary machine, pulleys such as a power steering pump and a generator (not shown) are connected to the pulley of the output shaft of the internal combustion engine 50 via a belt. The drive shaft of the air conditioner compressor 55 is provided with an electromagnetic clutch (not shown). The electromagnetic clutch is intermittently controlled under the control of the ECU 40 in accordance with ON / OFF of an air conditioner SW (not shown), whereby the air conditioner compressor 55 is driven and stopped.

  The ECU 40 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 40 is mainly configured to control the internal combustion engine 50. In this embodiment, the ECU 40 also controls the electric throttle 13 and VSV1. In addition to the electric throttle 13 and the VSV 1, various control objects are connected to the ECU 40 via a drive circuit (not shown). The ECU 40 includes an encoder, an accelerator sensor (not shown) for detecting the state of the accelerator pedal, a crank angle sensor (not shown) for detecting the rotational speed Ne of the internal combustion engine 50, and various sensors such as an air conditioner SW. It is connected.

  The ROM is configured to store a program in which various processes executed by the CPU are described. In the present embodiment, the function of the ejector 30 is set under various conditions in addition to the program for controlling the internal combustion engine 50, or A VSV 1 control program for controlling the VSV 1 so as to stop the function, an ISC control program for controlling the electric throttle 13 by ISC (Idle Speed Control), and the like are also stored. However, these programs may be combined together. The ISC control program includes an ISC control request amount calculation program and an electric throttle control program for controlling the electric throttle 13 based on the calculated final ISC control request amount (hereinafter also simply referred to as eqcal). It is configured. When VSV1 is controlled so as to make the ejector 30 function (hereinafter, also simply referred to as when VSV1 is turned on), eqcal is an ordinary ISC control amount (hereinafter, referred to as VSC1 calculation program). It is calculated by subtracting a control amount (hereinafter also simply referred to as eqeject) corresponding to an intake flow rate that increases when VSV1 is turned on from simply eqcalb). On the other hand, when VSV1 is controlled so as to stop the function of ejector 30 (hereinafter also referred to simply as VSV1 being turned off), this ISC control request amount calculation program calculates eqcal as eqcalb. Done. In the present embodiment, eqcalb is specifically composed of various control amounts shown below.

  eqcalb is composed of eqg, eqi, eqdlnt, eqsta, eqthw, eqac, eqels, eqcat, eqdln, eqaenst, eqps, eqps, eqnd, eqpg, eqvtf, and eqaddmax. Note that these various control amounts constituting eqcalb may have negative values. These various control amounts are calculated by the ISC control request amount calculation program, and eqcalb is calculated by the ISC control request amount calculation program as the sum of these various control amounts. Here, eqg is a control amount for learning control of the electric throttle 13. eqi is a control amount for feedback control of the electric throttle 13. eqdlnt is a control amount having a magnitude corresponding to the target rotational speed. eqsta is a control amount for increasing the rotational speed Ne when the internal combustion engine 50 is started. eqthw is a control amount having a size corresponding to the height of the water temperature. eqac is a control amount having a magnitude corresponding to the load of the air conditioner compressor 55. eqels is a controlled variable having a magnitude corresponding to the generator load. eqcat is a control amount for increasing the intake flow rate in accordance with the catalyst warm-up control. eqdln is a control amount for increasing the intake air flow rate when the rotational speed Ne decreases due to disturbance or the like. eqaenst is a control amount for avoiding engine stall.

  eqps is a control amount having a magnitude corresponding to the driving load of the power steering pump. eqnd is a control amount having a magnitude corresponding to the load of the transmission (not shown) in the driving and non-driving ranges. eqpg is a control amount for performing correction according to the purge amount of the evaporated fuel. eqvtf is a control amount for performing correction when a VVT (Variable Valve Timing) mechanism (not shown) fails toward the advance side. eqaddmax is a control amount having a magnitude corresponding to the maximum value of the final standard flow rate. Note that the largest one of eqdp (dashpot correction amount), eqdwn (deceleration idle-up correction amount), and eqcrs (travel correction amount) is selected as eqddmax. Among the various control quantities described above, eqdlnt, eqsta, eqthw, eqac, eqels, eqcat, eqvtf, and eqaddmax are control quantities that do not require responsiveness.In this embodiment, the sum of these control quantities is The ISC required control amount calculation program calculates a predetermined control amount that does not require responsiveness (hereinafter also simply referred to as eqejeb).

  In the present embodiment, the VSV1 control program is configured to have a program for turning on VSV1 when eqejeb is larger than eqeject. Note that eqejeb indicates the intake flow rate required by the internal combustion engine 50, and eqeject indicates the intake flow rate that increases when VSV1 is turned on. In the present embodiment, various control means, detection means, determination means, and the like are realized by the CPU, ROM, RAM (hereinafter also referred to as CPU, etc.) and the above-described various programs, and in particular, the CPU and the VSV1 control program. Thus, priority control means is realized. 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 40 to control the VSV 1 will be described in detail with reference to a flowchart shown in FIG. The ECU 40 controls the negative pressure generating device 100 by repeatedly executing the processing shown in the flowchart in a very short time based on the above-described VSV1 control program and ISC control request amount calculation program stored in the ROM. To do. The CPU executes a process for calculating eqejeb (step 11). Subsequently, the CPU detects the rotation speed Ne based on the output signal of the crank angle sensor, detects the load based on the output signal of the encoder, and executes a process of calculating eqeject based on the detected rotation speed Ne and the load (step). 12). In this embodiment, map data of the estimated intake flow rate defined according to the rotational speed Ne and the load is stored in the ROM, and eqeject is calculated based on this estimated intake flow rate. The estimated intake flow rate is an estimated value of the intake flow rate that increases when the VSV 1 is turned on, and is determined in advance based on the measurement result of the bench test or the like. However, the present invention is not limited to this. For example, eqeject may be directly stored in the ROM instead of the estimated intake flow rate.

  Subsequently, the CPU executes processing for determining whether there is a negative pressure securing request or whether eqejeb is larger than eqeject (step 13). That is, it is determined whether or not the negative pressure is required in this step, and whether or not the idle speed can be maintained even if the ejector 30 is functioned and whether or not the idle speed can be controlled. The negative pressure securing request is made, for example, when the negative pressure in the negative pressure chamber of the brake booster 22 does not satisfy the reference value or when there is a pumping brake. Even if there is no negative pressure securing request, if the determination is affirmative in step 13, the CPU executes a process for turning on VSV1 (step 14). Thereby, the opportunity to make the ejector 30 function can be increased. Note that this step may be skipped if VSV1 is already ON. Subsequently, the CPU executes a process of calculating eqcal by subtracting eqeject from eqcalb (step 15). The electric throttle 13 is controlled based on the eqcal calculated in this step. That is, in the present embodiment, the electric throttle 13 is controlled based on the eqcal calculated in step 15 after VSV1 is turned on in step 14, and thus the VSV 1 is turned on in preference to the electric throttle 13. be able to.

  If a negative determination is made in step 13, the CPU executes a process for turning off VSV1 (step 16), and executes a calculation process for setting eqcalb to eqcal (step 17). Thereby, since the ejector 30 is functioning, it is possible to prevent the maintenance of the idle speed from being adversely affected and the controllability of the idle speed from being impaired. In this case, the VSV 1 does not contribute to the intake flow rate, and the intake flow rate is adjusted only by the electric throttle 13. That is, if a negative determination is made in step 13, the electric throttle 13 is controlled with priority over VSV1. If there is a negative pressure securing request in step 13, VSV1 is turned on in step 13 regardless of whether eqejeb is larger than eqeject. Thereby, the ejector 30 can be made to function suitably as needed from a viewpoint of safety improvement, such as ensuring brake performance. As described above, the ECU 40 can be prioritized to ensure the negative pressure by the ejector 30, and the ECU 40 that can improve the problem of delay in responsiveness at the time of shifting to securing the negative pressure can be realized by increasing the opportunities for the ejector 30 to function.

  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 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 ECU40 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 55 Compressor for air conditioner 100 Ejector system

Claims (3)

The internal combustion engine includes: 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 the internal combustion engine; and a state changing unit that causes the ejector to function or stop functioning. A control device for a negative pressure generating device for controlling a negative pressure generating device disposed in a path independent of an idle flow rate adjusting means for adjusting an intake flow rate at the time of idling,
Negative pressure generation characterized by comprising priority control means for controlling the state changing means in preference to the idle flow rate adjusting means when adjusting the intake flow rate required for the internal combustion engine during idling. Control device for the device. Further, when the intake air flow rate required by the internal combustion engine is larger than the intake air flow rate that increases when the state change unit is controlled, the priority control unit causes the state change unit to function the ejector. The control device for a negative pressure generating device according to claim 1, wherein the control device is controlled. The intake air flow rate required by the internal combustion engine is an intake air flow rate indexed by a predetermined control amount that does not require responsiveness among control amounts for controlling the idle flow rate adjusting means. Item 3. The control device for the negative pressure generator according to Item 1 or 2.

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