JP2007309230A - Control quantity calculation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control quantity calculation device capable of suitably performing ISC control, air fuel ratio control or the like by correcting delay of response of intake air flow quantity gradually increasing when an ejector is functioned. <P>SOLUTION: ECU 40 calculates control quantity for controlling an electric throttle 13 adjusting quantity of intake air supplied to an internal combustion engine 50, and is used together with a vehicular ejector system 100 constructed with including an ejector 30 generating negative pressure higher than negative pressure to be taken out from an intake manifold 14, VSV1 functioning or stopping function of the ejector 30, and ECU 40 controlling the VSV1. The ECU 40 is provided with a response correction control quantity calculation means calculating eqeject for controlling the electric throttle 13 to increase intake air flow rate when the VSV1 is controlled to function the ejector 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control amount calculation device, and more particularly to a control amount calculation device used with a vehicle ejector system.

  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 vehicle control device including a correction unit that corrects an intake air amount (hereinafter also referred to as an intake air flow rate) taken into the internal combustion engine based on an operating state of the ejector. .

JP 2005-69175 A

  In idling, ISC control is generally performed to control the idling speed by controlling intake flow rate adjusting means such as an ISC (Idle Speed Control) valve and a throttle valve. ISC control is based on feedback control (hereinafter also simply referred to as F / B control) for controlling the intake flow rate adjusting means so as to suppress fluctuations in the idle speed of the internal combustion engine, and the control results of F / B control. , Learning control for controlling the intake flow rate adjusting means so as to maintain the idle speed at the target rotational speed, and the intake flow rate adjusting means for changing the target rotational speed according to the operating state of the air conditioner or the magnitude of the electric load It has the correction control etc. which control this. Under ISC control, the intake flow rate is adjusted to a necessary intake flow rate necessary for operating the internal combustion engine at the target rotational speed by these controls. For this reason, when the ejector is made to function during idling, the intake air flow rate increases, while the intake air flow rate is reduced by F / B control in order to suppress fluctuations in the idle rotation speed.

  FIG. 5 is a diagram schematically showing a change in the flow rate of the intake air flowing through the bypass when the ejector functions. Here, the internal flow path of the ejector corresponding to the portion that generates the negative pressure by the Venturi effect is a throttle. For this reason, when the ejector is made to function, the intake flow rate does not increase instantaneously but gradually increases, and as a result, the response until the intake flow rate increases to the final magnitude is delayed. However, in Patent Document 1, there is no particular mention about the increase mode of the intake flow rate. Therefore, in the vehicle control device proposed by Patent Document 1, when the ejector is made to function, the intake flow rate is reduced collectively by correction. it is conceivable that. That is, in the vehicle control device proposed in Patent Document 1, although fluctuations in the intake flow rate are finally suppressed, in a transient state, the intake flow rate may temporarily decrease depending on the timing of correction. was there.

  On the other hand, an increase in the intake flow rate during idling is generally suppressed by F / B control performed by ISC control, but in this case, fluctuations in the idling speed are allowed to some extent. Further, the F / B control performed by the ISC control is generally performed based on the difference between the required intake flow rate and the detected intake flow rate. Therefore, even when the vehicle control device proposed in Patent Document 1 is used, depending on a specific correction mode such as correcting the detected intake flow rate, the increase mode of the intake flow rate may be considered in the correction. Similarly, there has been a risk that fluctuations in the idle speed will be inevitably allowed due to the F / B control.

  Therefore, the present invention has been made in view of the above problems, and it is possible to suitably perform idle control, air-fuel ratio control, and the like by correcting a delay in response of the intake flow rate that gradually increases when the ejector functions. It is an object of the present invention to provide a control amount calculation apparatus capable of doing so.

  In order to solve the above problems, the present invention calculates a control amount for controlling an intake air flow rate adjusting means for adjusting an intake air flow rate supplied to an internal combustion engine, and extracts it from an intake passage of an intake system of the internal combustion engine. An ejector system for a vehicle comprising: an ejector that generates a negative pressure greater than the negative pressure to be detected; a state changing unit that functions or stops the function of the ejector; and a control device that controls the state changing unit A control amount calculation apparatus used together with a responsiveness correction for controlling the intake flow rate adjusting means so that the intake flow rate increases when the state changing means is controlled to make the ejector function. Responsiveness correction control amount calculation means for calculating a control amount for operation is provided.

  According to the present invention, the intake air flow rate can be quickly increased by the intake air flow rate adjusting means when the ejector is made to function. That is, according to the present invention, it is possible to correct a delay in response of the intake flow rate that gradually increases when the ejector is made to function. As a result, the intake flow rate that gradually increases when the ejector functions can be considered as an intake flow rate that instantaneously increases. Therefore, for example, it is easy to perform ISC control using the ejector as a correction control target in ISC control, and it is possible to more appropriately suppress fluctuations in the idle rotation speed. Further, if the ejector is a target of correction control in ISC control, it is possible to suitably suppress fluctuations in the idle rotation speed due to F / B control. In addition, according to the present invention, it is not limited to idling. For example, even when the ejector is operated during vehicle acceleration, it can be considered that the intake flow rate increases instantaneously. Therefore, the air-fuel ratio control can be suitably performed.

  Further, in the present invention, the responsiveness correction control amount calculation means may change the responsiveness correction control amount so that the intake flow rate gradually decreases. According to the present invention, even if the intake flow rate actually flowing through the bypass passage gradually increases due to the function of the ejector, it can be continuously considered that the intake flow rate has increased instantaneously.

  According to the present invention, a control amount calculation capable of suitably performing ISC control, air-fuel ratio control, and the like by correcting a delay in response of the intake flow rate that gradually increases when the ejector functions. Equipment 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 schematically shows a control amount calculation apparatus according to the present embodiment realized by an ECU (Electronic Control Unit) 40 together with a vehicle ejector system (hereinafter simply referred to as an ejector system) 100. FIG. 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 degree. In this embodiment, the electric throttle 13 implements an intake flow rate adjusting means. In this embodiment, the electric throttle 13 is also configured to adjust the intake air flow rate in order to control the idle speed. The throttle body 13b is composed of a cylindrical member in which an intake passage is formed, and pivotally supports a valve shaft 13c of a throttle valve 13a disposed in the intake passage. The electric motor 13d is configured to change the opening degree of the throttle valve 13a under the control of the ECU 40A, and a step motor is adopted as the electric motor 13d. The electric motor 13d is fixed to the throttle body 13b, and its output shaft (not shown) is connected to the valve shaft 13c. The opening degree of the throttle valve 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 idling speed can be controlled by interposing a so-called ISC valve capable of controlling the degree of shielding of the flow path in the bypass path. . Therefore, this ISC valve can be used as the intake 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 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 is connected to various sensors such as an encoder, an accelerator sensor (not shown) for detecting the state of the accelerator pedal, and a crank angle sensor (not shown) for detecting the rotational speed Ne of the internal combustion engine 50. . In the present embodiment, the ECU 40 implements a control device related to the ejector system 100 together with the control amount calculation device.

  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 VSV1 control program for controlling the VSV1 so as to stop the function, an ISC control program for performing ISC control of the electric throttle 13, and the like are also stored. However, these programs may be combined together. In this embodiment, when the VSV 1 is controlled so as to make the ejector 30 function (hereinafter, also simply referred to as ON), the response correction for controlling the electric throttle 13 so that the intake air flow rate increases. A responsiveness correction control amount calculation program (hereinafter also simply referred to as a calculation program) for calculating a control amount (hereinafter also simply referred to as eqeject) is stored in the ROM. Specifically, this eqeject is a control amount for controlling the electric throttle 13 so that the intake air flow rate is increased by an estimated intake air flow rate corresponding to the intake air flow rate that finally increases when the VSV 1 is turned ON. It has become. The calculation program further includes a program for changing eqeject so that the intake flow rate gradually decreases. In this program, eqeject is changed so that the intake flow rate gradually decreases as the intake flow rate actually flowing through the bypass passage B gradually increases.

  Note that the estimated intake air flow rate is determined in advance based on the measurement result of the bench test or the like, and is stored in the ROM. The estimated intake flow rate is preferably defined by map data in accordance with the operating state of the internal combustion engine 50. In this embodiment, the estimated intake flow rate is defined by map data in accordance with the rotational speed and load. 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. In this case, eqeject is calculated by reading eqeject from the ROM according to the operating state. In this 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. Responsiveness correction control amount calculation means is realized by the control amount calculation program. In this embodiment, the ejector system 100 is realized by the VSV 1, the ejector 30, and the ECU 40.

  Next, processing performed by the ECU 40 when calculating and changing eqeject when the VSV 1 is turned on will be described in detail with reference to the flowchart shown in FIG. The ECU 40 calculates and changes eqeject by repeatedly executing the process shown in the flowchart in a very short time based on the above-described calculation program stored in the ROM. The CPU executes processing for determining whether or not VSV1 is turned on (step 11). Whether or not VSV1 is turned on can be determined by the CPU confirming the state of internal processing based on the VSV1 control program executed by the ECU 40. However, the present invention is not limited to this, and when the VSV 1 includes, for example, a limit switch that can detect the operating state of the VSV 1, a determination may be made based on the output signal of the limit switch.

  If the determination is affirmative, the CPU detects the rotational 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 rotational speed Ne and the load. (Step 12). By using the eqeject calculated in this step for the control of the electric throttle 13, it can be considered that the intake flow rate that gradually increases when the VSV 1 is turned on instantaneously increases. Subsequently, the CPU executes a process for changing eqeject (step 13). Specifically, in this embodiment, the current eqeject is reduced by the equation shown in Step 13 to calculate a new eqejectT, and the eqeject is updated by updating the eqeject with eqejectT. However, the present invention is not limited to this, and eqeject may be changed using another appropriate calculation formula, or eqeject may be changed using map data or the like. Subsequently, the CPU executes a process for determining whether or not eqeject has become 0 (zero) (step 14). If a negative determination is made in step 14, the CPU executes step 13 again. That is, eqeject can be gradually decreased by repeatedly executing steps 13 and 14 until eqeject becomes 0 (zero). In addition, by using the eqeject calculated in step 13 for controlling the electric throttle 13 at this time, even if the intake flow rate actually flowing through the bypass passage B gradually increases after VSV1 is turned ON, the intake flow rate Can continue to be thought of as a momentary increase. If the determination is negative in step 11, the CPU repeatedly executes step 11. If the determination is affirmative in step 14, the CPU returns to step 11.

  FIG. 4 is a diagram schematically showing changes in the operating state, eqeject, and intake air flow rate of the VSV 1 corresponding to the flowchart shown in FIG. A curve C1 shows a change in the flow rate of the intake air flowing through the bypass passage B. When VSV1 is turned on, eqeject is calculated in step 12, thereby increasing eqeject. After that, the eqeject is gradually changed in steps 13 and 14, so that the eqeject gradually decreases. By using this eqeject for controlling the electric throttle 13, the intake air flow rate changes as shown by the curve C2 as a whole. As a result, the intake flow rate that gradually increases when VSV1 is turned on can be considered as an intake flow rate that instantaneously increases. Therefore, for example, it is easy to perform ISC control with the ejector 30 as a correction control target in ISC control, and accordingly, fluctuations in the idle speed can be more suitably suppressed. Further, for example, even when VSV1 is turned ON during vehicle acceleration, it can be considered that the intake air flow rate instantaneously increases. Therefore, correction of the fuel injection amount and the like are easy in timing, and air-fuel ratio control is also suitable. Will be able to do. As described above, it is possible to realize the ECU 40 that can suitably perform ISC control, air-fuel ratio control, and the like by correcting the delay in response of the intake flow rate that gradually increases when the ejector 30 functions. is there.

  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.

1 is a diagram schematically showing an ECU 40 together with an ejector system 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. It is a figure which shows typically the change of the operating state of VSV1, the eqeject, and the intake flow rate corresponding to the flowchart shown in FIG. It is a figure which shows typically the flow volume change of the intake air which distribute | circulates a bypass path when an ejector is functioned.

Explanation of symbols

1 VSV
10 Intake System 13 Electric Throttle 20 Brake Device 30 Ejector 40 ECU
50 Internal combustion engine 100 Ejector system

Claims (2)

A control amount for controlling the intake flow rate adjusting means for adjusting the intake flow rate supplied to the internal combustion engine is calculated, and 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 is generated. A control amount calculation device used with a vehicle ejector system including an ejector, a state changing unit that causes the ejector to function or stop functioning, and a control device that controls the state changing unit,
A responsiveness correction control amount for calculating a responsiveness correction control amount for controlling the intake air flow rate adjusting means so that the intake air flow rate increases when the state changing means is controlled to cause the ejector to function. A control amount calculation apparatus comprising a calculation means. 2. The control amount calculation apparatus according to claim 1, wherein the responsiveness correction control amount calculation unit changes the responsiveness correction control amount so that the intake flow rate gradually decreases.

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