JP5087566B2 - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine, improving the restartability of the internal combustion engine after failing in its automatic start. <P>SOLUTION: The control device 60 controls the opening/closing of a throttle valve 21 provided in an intake passage 20 of the internal combustion engine 10 to automatically stop the internal combustion engine 10 when predetermined automatically stopping conditions are established, or to automatically start the internal combustion engine 10 when predetermined automatically starting conditions are established. When automatically starting the internal combustion engine 10, it sets the opening of the throttle valve 21 to be a predetermined value &Delta;Q smaller than an opening D0 required during idling so that the amount of intake air to be supplied to the internal combustion engine 10 is reduced to improve fuel consumption and reduce exhaust gas. The control device 60 detects a failure in automatically starting the internal combustion engine 10. When detecting a failure in automatically starting the internal combustion engine 10, it makes the opening of the throttle valve 21 at restarting the internal combustion engine 10 greater than the opening previously set at automatically starting it. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a technique for improving restartability after an automatic start failure of an internal combustion engine.

  2. Description of the Related Art Conventionally, for the purpose of improving fuel consumption, a vehicle having an eco-run function that automatically stops an internal combustion engine when a predetermined automatic stop condition is satisfied is known. In such a vehicle, the internal combustion engine is automatically started when a predetermined automatic start condition is satisfied after the internal combustion engine is automatically stopped.

  Here, for example, in Patent Document 1, in a vehicle having an eco-run function, when the internal combustion engine is automatically started, the throttle opening is limited to a predetermined opening regardless of the accelerator request, and the amount of intake air supplied to the internal combustion engine is set. Techniques for reducing are disclosed. According to this technique, the engine blow-up can be suppressed when the internal combustion engine (engine) is automatically started. As a result, fuel consumption can be improved.

JP 2006-152965 A

  However, according to the technique disclosed in Patent Document 1, the amount of intake air supplied to the internal combustion engine when the internal combustion engine is automatically started is limited. In addition, there has been a risk that the automatic start of the internal combustion engine may fail due to an operation error of the driver (engine stall). As described above, when the automatic start of the internal combustion engine ends in failure, the exhaust gas flows backward to the intake passage (intake manifold) side where the negative pressure is generated due to the restriction of the throttle opening. When the internal combustion engine is restarted due to the backflow of the exhaust gas, there is a problem that startability is deteriorated.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device for an internal combustion engine that can improve restartability after failure of automatic start of the internal combustion engine. To do.

In order to solve the above problems, an internal combustion engine control apparatus according to the present invention includes an open / close control means for controlling opening / closing of a throttle valve provided in an intake passage of the internal combustion engine, and an internal combustion engine when a predetermined automatic stop condition is satisfied. An automatic stopping means for automatically stopping; and an automatic starting means for automatically starting the internal combustion engine that has been automatically stopped by the automatic stopping means when a predetermined automatic start condition is satisfied, wherein the internal combustion engine is automatically started by the automatic starting means In addition, the open / close control means is a control device for an internal combustion engine that reduces the intake air amount supplied to the internal combustion engine by setting the opening of the throttle valve by a predetermined value smaller than the opening required at the normal start. , equipped with an automatic start failure detection means for detecting a failure of the automatic start of the internal combustion engine occurring when reducing the intake air amount of the supply, the automatic start failure detection means If the failure of the automatic start of the engine is detected, the switching control means, the opening degree of the throttle valve at the time of restart of the internal combustion engine, greater than the opening degree set during the previous automatic startup and normal start It is characterized by being made smaller than the opening required at times .
Here, as the “predetermined value”, for example, an opening degree of about 2/3 of an opening degree required during normal starting (normal starting opening degree) can be exemplified.

  In the control apparatus for an internal combustion engine according to the present invention, the automatic start means automatically starts the internal combustion engine when a predetermined automatic start condition is satisfied. At this time, the opening / closing control means sets the opening of the throttle valve smaller than the normal starting opening by a predetermined value. As a result, it is possible to reduce the amount of intake air supplied to the internal combustion engine, suppress the blow-up, and improve fuel efficiency. By the way, when the amount of intake air supplied to the internal combustion engine decreases and the internal combustion engine fails to start automatically due to a driver's operation error or the like, exhaust gas is generated on the intake passage side where negative pressure is generated due to restriction of the throttle opening. It will flow backward and the restartability will be worsened. Therefore, in this apparatus, when the automatic start failure detecting means detects the failure of the automatic start, the opening / closing control means sets the opening degree of the throttle valve when the internal combustion engine is restarted to the opening set at the previous automatic start. It is set larger than the degree. As a result, when the internal combustion engine is restarted after a failure in automatic start, the amount of intake air supplied to the internal combustion engine can be increased. As a result, even if the automatic start of the internal combustion engine fails and the exhaust gas flows backward to the intake passage side, a sufficient intake amount is supplied to the internal combustion engine at the next automatic start of the internal combustion engine to restart the engine. Can be improved.

  In this control device, the intake amount to the internal combustion engine at the time of restart is increased by controlling the opening and closing of the throttle valve provided in the intake passage. Thereby, for example, the present invention can be easily realized as compared with the case where the intake valve provided for each cylinder of the internal combustion engine is controlled.

  In the control apparatus for an internal combustion engine according to the present invention, the opening / closing control means reduces the predetermined value to reduce the opening of the throttle valve from the opening set at the previous automatic start when the internal combustion engine is restarted. The aspect which enlarges can be illustrated.

  In this control device, by reducing the predetermined value, the amount of intake air supplied to the internal combustion engine can be easily increased when the internal combustion engine is restarted after the automatic start failure. Thereby, the restartability after the automatic start failure of the internal combustion engine can be easily improved.

  In the control device for an internal combustion engine according to the present invention, the opening / closing control means sets the opening degree of the throttle valve to the opening degree set at the time of the previous automatic start when the internal combustion engine is restarted by setting the predetermined value to zero. The aspect which makes it larger can be illustrated.

  In this control device, when the predetermined value is set to zero, the amount of intake air supplied to the internal combustion engine can be more easily and reliably increased when the internal combustion engine is restarted after the automatic start failure. Thereby, the restartability after the automatic start failure of the internal combustion engine can be improved more easily and reliably.

  According to the control device for an internal combustion engine according to the present invention, as described above, the restartability after the automatic start failure of the internal combustion engine can be improved.

It is a whole lineblock diagram showing the engine system concerning a 1st embodiment of the present invention. It is a flowchart which shows the control content which ECU of the system performs. It is a timing chart which shows the behavior of an engine and a throttle valve by control of ECU of the system. It is a flowchart which shows the control content which ECU of the engine control system which concerns on 2nd Embodiment of this invention performs. It is a flowchart which shows the control content which ECU of the engine control system which concerns on 3rd Embodiment of this invention performs.

[First Embodiment]
Hereinafter, an embodiment of an engine system embodying a control device for an internal combustion engine according to the present invention will be described with reference to the drawings. First, the overall configuration of the engine system according to the first embodiment will be described with reference to FIG. FIG. 1 is an overall configuration diagram showing an engine system according to a first embodiment of the present invention.
As shown in FIG. 1, the engine system includes an engine 10 that serves as a power source for the vehicle, and an ECU 60 that controls the engine system as a whole. The engine 10 of the present embodiment corresponds to the “internal combustion engine” of the present invention, and the ECU 60 of the present embodiment corresponds to the “control device for the internal combustion engine” of the present invention.

  As shown in FIG. 1, the engine 10 includes a combustion chamber 11 that combusts a mixed gas of fuel and intake air, an intake passage 20 that serves as a passage for supplying intake air to the combustion chamber 11, and exhaust gas discharged from the combustion chamber 11. And an exhaust passage 30 serving as a passage.

  The combustion chamber 11 includes an intake port 12 that communicates with the intake passage 20 and an exhaust port 14 that communicates with the exhaust passage 30. The intake port 12 is provided with an intake valve 13. The intake port 12 is opened and closed by driving the intake valve 13. The exhaust port 14 is provided with an exhaust valve 15. The exhaust port 14 is opened and closed by driving the exhaust valve 15.

  The intake passage 20 includes a throttle valve 21 that is provided in the middle of the passage 20 and controls the flow rate of intake air, and a throttle sensor 22 that detects the opening of the throttle valve 21. The throttle sensor 22 is connected to the ECU 60.

  The ECU 60 includes a microcomputer that performs electronic control of each part of the engine system. As is well known, the microcomputer includes a central processing unit (CPU), a read / write memory (RAM), a read only memory (ROM), and the like, and performs processing of signals input to the ECU 60 and the like. The ECU 60 is connected to various sensors, switches, and the like. For example, the brake ON / OFF signal from the brake switch 61, the engine rotational speed from the rotational speed sensor 62, and the door OPEN / CLOSE from the driver seat door switch 63. Signal, OPEN / CLOSE signal of the hood from the engine hood switch 64, ON / OFF signal of the winker and hazard from the turn switch 65, the accelerator depression amount from the accelerator opening sensor 66, the shift position from the shift position switch 67, the vehicle speed The vehicle speed from the sensor 68 is received as an input. The ECU 60 of this embodiment also serves as the “open / close control means”, “automatic stop means”, “automatic start means”, and “automatic start failure detection means” of the present invention.

  Next, the control content performed by the ECU 60 of the present embodiment will be described with reference to FIG. FIG. 2 is a flowchart showing the contents of control performed by the ECU of the system.

  As shown in FIG. 2, in step S21, the ECU 60 determines whether or not an automatic stop condition for the engine 10 is satisfied. The automatic stop conditions are: (1) turn signal and hazard are OFF, (2) vehicle speed is zero, (3) shift range is N range (neutral position), and (4) engine hood is For example, it may be closed, and (5) the door of the driver's seat is closed. When the ECU 60 determines that the automatic stop condition is not satisfied (S21: No), for example, when any one of the above conditions (1) to (5) is not satisfied, the subsequent processing ends. To do. On the other hand, when the ECU 60 determines that the automatic stop condition is satisfied (S21: Yes), for example, when all of the above conditions (1) to (5) are satisfied, the process proceeds to step S22.

  In step S22, the ECU 60 automatically stops the engine 10. In the engine system according to the present embodiment, such an eco-run function can improve fuel consumption and reduce exhaust gas. And ECU60 transfers a process to step S23.

  In step S23, the ECU 60 determines whether or not an automatic start condition for the engine 10 is satisfied. The automatic start conditions are (6) the shift range is the D range (forward position) or the R range (reverse position), (7) the brake switch is ON, and (8) the accelerator depression amount is zero. Can be mentioned. When the ECU 60 determines that the automatic start condition is not satisfied (S23: No), for example, when any one of the above conditions (6) to (8) is not satisfied, the subsequent processing is ended. To do. On the other hand, when the ECU 60 determines that the automatic start condition is satisfied (S23: Yes), for example, when all of the above conditions (6) to (8) are satisfied, the process proceeds to step S24.

In step S24, the ECU 60 starts the automatic start of the engine 10. And ECU60 transfers a process to step S25.
In step S25, the ECU 60 decreases the opening degree of the throttle valve 21 by ΔQ from the opening degree (normal starting opening degree) D0 required during normal starting (see FIG. 3). This ΔQ corresponds to the “predetermined value” of the present invention. Thus, by reducing the amount of intake air supplied to the engine 10, it is possible to suppress a blow-up at the time of automatic start of the engine 10 and improve fuel efficiency. And ECU60 transfers a process to step S26.

  In step S26, the ECU 60 determines whether an engine stall (engine stall) has been detected. Specifically, the ECU 60 detects the engine stall based on the engine speed obtained from the speed sensor 62, for example. Then, when the engine stall is not detected (S26: No), the ECU 60 ends the subsequent processing. On the other hand, when the engine stall is detected (S26: Yes), the ECU 60 proceeds to step S27.

  In step S27, the ECU 60 sets the next reduction amount of the throttle opening to ΔQ / 2. Then, the ECU 60 ends the subsequent processing. Thereby, the amount of intake air to the engine 10 at the next automatic start can be increased by ΔQ / 2 from the previous time. As a result, even if the automatic start of the engine 10 fails and the exhaust gas flows backward to the intake passage 20 side, a sufficient intake amount is supplied to the engine 10 at the next automatic start of the engine 10 and restarted. Can be improved.

  If the engine 10 also fails to restart, the ECU 60 may set the amount of decrease in the throttle opening at the next start to a value smaller than the previous time, for example, ΔQ / 4. Thereby, the startability of the engine 10 at the next automatic start can be improved more reliably.

  Next, an example of behaviors exhibited by the engine 10 and the throttle valve 21 under the control of the ECU 60 will be described with reference to FIG. FIG. 3 is a timing chart showing the behavior of the engine and the throttle valve under the control of the ECU of this system.

  As shown in FIG. 3B, since the shift range is the D range before time t1, the condition (1) is not satisfied and the automatic stop condition is not satisfied (step S21: No). Therefore, the ECU 60 does not automatically stop the engine. At time t1, since the shift range becomes the N range (assuming that other automatic stop conditions are satisfied), the ECU 60 determines that the automatic stop condition is satisfied (step S21: Yes). Then, as shown in FIG. 3A, the ECU 60 automatically stops the engine 10 (step S22).

Between time t1 and time t2, as shown in FIG. 3B, the shift range remains the N range, so the above condition (6) is not satisfied and the automatic start condition is not satisfied (step S23: No).
Thereafter, at time t2, since the shift range is the D range and the brake switch is ON (other automatic start conditions are satisfied), the ECU 60 determines that the automatic start conditions are satisfied (step S23: Yes). Then, as shown in FIG. 3A, the ECU 60 starts the automatic start of the engine 10 (step S24). At this time, as shown in FIG. 3D, the ECU 60 sets the opening degree of the throttle valve 21 to an opening degree D1 that is reduced by ΔQ from the normal starting opening degree D0. As a result, the amount of intake air supplied to the engine 10 decreases, so that the engine speed is prevented from rising. The time Δt for reducing the intake air amount is not particularly limited, but may be about several seconds, for example.

  By the way, in this example, as shown in FIG. 3C, the brake is turned off at time t3 due to a malfunction, a driver's error, or the like. For this reason, the engine 10 fails to start automatically as shown in FIG. That is, the ECU 60 detects the engine stall (step S26: Yes). Here, if the engine 10 fails to start automatically, the exhaust gas flows backward to the intake passage 20 side where the negative pressure is generated due to the restriction of the throttle valve 21 to the opening degree D1. When the engine 10 is restarted due to the backflow of the exhaust gas, the startability may be deteriorated. Therefore, the ECU 60 sets the amount of decrease in the throttle opening at the next start to ΔQ / 2 (step S27). At time t4, the brake is turned on, the automatic start condition is satisfied again, and the ECU 60 starts restarting the engine 10. At this time, as shown in FIG. 3 (d), the ECU 60 sets the opening degree of the throttle valve 21 to an opening degree D2 that is reduced by ΔQ / 2 from the normal starting opening degree D0. As a result, when the engine 10 is restarted, the amount of intake air supplied to the engine 10 can be increased by an amount corresponding to ΔQ / 2 from the previous start.

  As described above, according to the engine system according to the present embodiment as described in detail, when the ECU 60 detects a failure in the automatic start of the engine 10, the opening degree D2 of the throttle valve 21 when the engine 10 is restarted is set. The opening degree D1 set at the previous automatic start is set larger. As a result, even if the automatic start of the engine 10 fails and the exhaust gas flows backward to the intake passage 20 side, a sufficient intake amount is supplied to the engine 10 at the next automatic start of the engine 10 and restarted. Can be improved.

  Further, in this system, the amount of intake air to the engine 10 at the time of restart is increased by controlling opening and closing of the throttle valve 21 provided in the intake passage 20. For this reason, for example, the restartability of the engine 10 can be easily improved as compared with the case where the intake valve 13 provided for each cylinder of the engine 10 is controlled.

[Second Embodiment]
Next, a second embodiment of an engine system that embodies the control device for an internal combustion engine according to the present invention will be described with reference to FIG. FIG. 4 is a flowchart showing the contents of control performed by the ECU of the engine control system according to the second embodiment of the present invention.

  The engine system according to the second embodiment is different from that of the first embodiment in the control contents performed by the ECU 60. The overall configuration of the system is the same as that of the first embodiment, and the same reference numerals are used for the same components. Below, it demonstrates centering on difference with the said 1st Embodiment.

  In this system, as shown in FIG. 4, the automatic stop condition of the engine 10 is established and the engine 10 is automatically stopped (step S41: Yes, step S42), and the automatic start condition of the engine 10 is established and the engine 10 is When starting automatically (step S43: Yes, step S44), the ECU 60 decreases the throttle opening by ΔQ (step S45). Up to this point, the process is the same as in the first embodiment, but when the ECU 60 detects an engine stall (step S46), it sets the next throttle opening reduction amount to an appropriate value instead of ΔQ. (Step S47). Here, the appropriate value means a reduction amount of the throttle opening smaller than ΔQ in order to supply an intake air amount necessary for starting the engine 10 appropriately according to the state of the engine 10. Then, the ECU 60 ends the subsequent processing.

  In this way, by setting the amount of decrease in the next throttle opening to an appropriate value, the intake amount to the engine 10 at the next automatic start can be increased by an amount corresponding to the appropriate value from the previous time. As a result, even if the automatic start of the engine 10 fails and the exhaust gas flows backward to the intake passage 20 side, the engine 10 is supplied with an appropriate amount of intake air and restarted at the next automatic start of the engine 10. Can be improved effectively.

[Third Embodiment]
Next, a third embodiment of the engine system embodying the control device for an internal combustion engine according to the present invention will be described with reference to FIG. FIG. 5 is a flowchart showing the control contents performed by the ECU of the engine control system according to the third embodiment of the present invention.

  The engine system according to the third embodiment is different from that of the above-described embodiment in the control content performed by the ECU 60. Note that the overall configuration of the system is the same as that of the above-described embodiment, and thus the same reference numerals are used for the same components. Below, it demonstrates centering on difference with the said embodiment.

  In this system, as shown in FIG. 5, the automatic stop condition of the engine 10 is established and the engine 10 is automatically stopped (step S51: Yes, step S52), and the automatic start condition of the engine 10 is established and the engine 10 is When starting automatically (step S53: Yes, step S54), the ECU 60 decreases the throttle opening by ΔQ (step S55). Up to this point, the ECU 60 of the present embodiment is the same as the above embodiment, but when the engine stall is detected (step S56), the amount of decrease in the next throttle opening is set to zero instead of ΔQ ( Step S57). That is, if the automatic stop of the engine 10 fails, the ECU 60 does not decrease the throttle opening at the time of restart, but sets the normal start opening D0. Then, the ECU 60 ends the subsequent processing.

  Thus, by setting the amount of decrease in the next throttle opening to zero, the amount of intake air to the engine 10 at the next automatic start can be easily and reliably increased. Therefore, the restartability after the automatic start failure of the engine 10 can be easily and reliably improved.

  In addition, the said embodiment is only a mere illustration and does not limit this invention at all, Of course, various improvement and deformation | transformation are possible within the range which does not deviate from the summary.

  For example, in the embodiment, the conditions (1) to (5) are exemplified as the automatic stop condition. However, the present invention is not limited to this, and the automatic stop condition may be set using values of other sensors. Moreover, although the said conditions (6)-(8) were illustrated as an automatic start condition in the said embodiment, it is not restricted to this, You may set automatic stop conditions using values, such as another sensor.

10 Engine 11 Combustion chamber 20 Intake passage 21 Throttle valve 30 Exhaust passage 60 ECU
61 Brake switch 62 Rotational speed sensor 63 Driver seat door switch 64 Engine hood switch 65 Turn switch 66 Accelerator opening sensor 67 Shift position switch 68 Vehicle speed sensor D0 Normal start opening ΔQ Predetermined value

Claims (3)

Open / close control means for controlling opening / closing of a throttle valve provided in an intake passage of the internal combustion engine;
Automatic stop means for automatically stopping the internal combustion engine when a predetermined automatic stop condition is satisfied;
Automatic start means for automatically starting the internal combustion engine that has been automatically stopped by the automatic stop means when a predetermined automatic start condition is satisfied,
When the internal combustion engine is automatically started by the automatic starting means, the open / close control means sets the opening of the throttle valve to be smaller by a predetermined value than the opening required at the normal start, and the intake air supplied to the internal combustion engine A control device for an internal combustion engine for reducing the amount,
An automatic start failure detecting means for detecting a failure of the automatic start of the internal combustion engine that occurs when the intake air amount to be supplied is reduced ;
When the automatic start failure detecting means detects a failure of the automatic start of the internal combustion engine, the opening / closing control means sets the opening of the throttle valve when the internal combustion engine is restarted to the opening set at the previous automatic start. A control device for an internal combustion engine, characterized in that it is larger than the degree and smaller than the opening required at the time of normal starting . The control apparatus for an internal combustion engine according to claim 1,
The opening / closing control means makes the opening of the throttle valve larger than the opening set at the previous automatic start when the internal combustion engine is restarted by reducing the predetermined value. apparatus. The control apparatus for an internal combustion engine according to claim 1,
The opening / closing control means makes the opening of the throttle valve larger than the opening set at the time of the previous automatic start when the internal combustion engine is restarted by setting the predetermined value to zero. Control device.

Images