JP2010065640A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately control engine speed in the no-load operation state of an internal combustion engine. <P>SOLUTION: The engine includes: a main throttle valve 15 opening/closing an intake passage in conjunction with accelerator operation by a driver; a sub throttle valve 14 opening/closing the intake passage by a motor 13; and a link mechanism closing the main throttle valve 15 in conjunction with movement of the sub throttle valve 14 in an opening direction or in a closing direction in the no-load operation state. An ECU 30 controls the opening/closing of the sub throttle valve 14 by driving the motor 13. When the engine is in the non-load operation state and the driving of the sub throttle valve 14 is not controlled, engine output is limited. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an internal combustion engine control device, and more particularly to an internal combustion engine control device including a main throttle valve and a sub-throttle valve in one intake passage.

  2. Description of the Related Art Conventionally, there has been known a device in which two throttle valves are provided in an intake passage of an internal combustion engine, and the amount of air taken into a combustion chamber is adjusted by opening and closing these two throttle valves. As these two throttle valves, a main throttle valve that opens and closes in conjunction with the driver's accelerator operation and a sub-throttle valve that opens and closes by driving a motor are known (see, for example, Patent Document 1 and Patent Document 2).

  Patent Document 1 proposes an intake control device provided with a mechanism for opening and closing a main throttle valve in accordance with opening and closing of a sub-throttle valve. In this device, when the main throttle valve is in the fully closed state, the sub throttle valve is opened from the fully closed state by the motor, so that the rotation of the sub throttle valve in the opening direction is transmitted to the main throttle valve. The valve is opened at a small angle from the fully closed state. As a result, the opening of the main throttle valve is automatically set to the opening required for first idle.

Further, Patent Document 2 discloses that a return spring having a biasing force in the fully open direction is provided in the sub throttle valve, and, for example, when the motor is disconnected, the sub throttle valve is returned to the initial state (fully opened state) by the spring. Yes.
Japanese Patent No. 3925073 Japanese Utility Model Publication No. 2-135463

  However, for example, in a batteryless internal combustion engine, when the engine is combusted at the time of starting, but the electric power necessary to drive the motor of the sub-throttle valve cannot be supplied to the motor, the sub-throttle valve is It may be impossible to open and close. In such a case, the apparatus of Patent Document 1 cannot drive the sub-throttle valve, and therefore may not be able to open the main throttle valve to the opening required for the first idle. Further, as in Patent Document 2, in the configuration in which the sub-throttle valve is fully opened by the return spring when the motor is not energized, an excessive amount of air is introduced into the combustion chamber when the motor is not energized when the internal combustion engine is started. As a result, it is considered that the idle rotation speed increases excessively.

  Accordingly, the present invention has been made to solve the above-described problems, and mainly provides an internal combustion engine control apparatus capable of suitably controlling the engine rotation speed in an unloaded operation state of the internal combustion engine. Objective.

  The present invention employs the following means in order to solve the above problems.

  According to the first aspect of the present invention, the main throttle valve that opens and closes the intake passage in conjunction with the accelerator operation by the driver, the sub-throttle valve that opens and closes the intake passage by driving the motor, The present invention is applied to an internal combustion engine including an interlocking mechanism that closes the main throttle valve in conjunction with the movement of the sub-throttle valve in the opening direction or the closing direction. Further, the present invention provides an opening / closing control means for driving the motor to control the opening / closing of the sub-throttle valve, and the internal combustion engine is in a no-load operation state, and the opening / closing control means drives the sub-slot valve. Output control means for limiting the output of the internal combustion engine when control is impossible.

  In an internal combustion engine having a main throttle valve and a sub-throttle valve in the intake passage, the main throttle valve is closed to the target opening in conjunction with the sub-throttle valve when the internal combustion engine is in a no-load operation state such as during idle control. Thus, the intake air amount in the no-load operation state of the internal combustion engine is controlled. At this time, if the sub-throttle valve cannot be driven, the main throttle valve cannot be closed to the target opening. Therefore, it is conceivable that the intake air amount becomes excessive when the internal combustion engine is in a no-load operation state. According to the present invention, when the sub-throttle valve cannot be driven even when the internal combustion engine is in a no-load operation state, the engine rotational speed in the no-load operation state of the internal combustion engine is preferably set to limit the output of the internal combustion engine. Can be controlled.

  In an internal combustion engine in which an electrical load is driven by power supplied from a generator such as an AC generator, the driving voltage (second voltage value) of the motor of the sub-throttle valve is the driving voltage (second voltage) of the fuel injection valve and ignition device. 1 (voltage value of 1). In such a case, for example, when the internal combustion engine is started, there is a period during which the sub-throttle valve cannot be driven even though fuel injection and ignition are performed. During this period, it is conceivable that the amount of intake air during idling becomes excessive and the idling rotational speed increases excessively.

  In view of this, the invention according to claim 2 is applied to an internal combustion engine in which fuel injection and ignition are performed by power feeding from a generator rotating in synchronization with the output shaft of the internal combustion engine and the motor is driven. In addition, the present invention relates to a control device for an internal combustion engine that performs fuel injection and ignition when the voltage supplied from the generator becomes equal to or higher than a first voltage value. The open / close control means drives the motor to drive the sub-throttle valve when the voltage supplied from the generator becomes equal to or higher than a second voltage value higher than the first voltage value. And when the voltage supplied from the generator is not less than the first voltage value and less than the second voltage value, the output control means cannot control the drive of the sub-throttle valve. The output of the internal combustion engine is limited. According to this configuration, the output of the internal combustion engine is limited when fuel injection and ignition are being performed and the motor of the sub-throttle valve is not driven. It is possible to prevent the engine from over-rotating.

  The invention described in claim 3 is characterized in that fuel injection and ignition are performed and the motor is driven by directly supplying power from the generator without going through a power storage device. That is, in a generator that rotates in synchronization with the output shaft of the internal combustion engine, for example, when the internal combustion engine is started, the electromotive force of the generator increases as the engine speed increases. Therefore, as in the third aspect of the invention, in the configuration in which the electric power from the generator is directly supplied to the fuel injection valve, the motor, etc. without going through the power storage device such as the battery, the fuel injection and ignition are performed. A period during which the sub-throttle valve cannot be driven tends to occur. Therefore, by applying the present invention to a configuration in which the power storage device is not provided, it is possible to suitably obtain an effect of preventing over-rotation during no-load operation of the internal combustion engine.

  Further, when the sub-throttle valve is driven, the main throttle valve can be driven in the closing direction via the interlock mechanism. This makes it possible to control the intake air amount during no-load operation of the internal combustion engine. In view of this, the invention according to claim 4 releases the output restriction of the internal combustion engine when the drive of the sub-throttle valve is started. According to this configuration, since the output restriction of the internal combustion engine is released by driving the sub-throttle valve, it is possible to avoid the engine speed from becoming excessively small after the sub-throttle valve is driven. As a result, engine stall can be prevented from occurring.

  As a form of releasing the output restriction of the internal combustion engine, when the sub-throttle valve is driven, the output restriction may be released all at once, but it is desirable to gradually release the output restriction.

  In an internal combustion engine, idle control is performed according to the engine temperature. For example, when restarting after warming up the internal combustion engine, idle control is performed with a smaller intake air amount than during cold start. At this time, when the main throttle valve is not driven by a motor, in the configuration in which the valve is set to the opening side more than the opening required for idle control after warm-up, when the internal combustion engine is restarted after warm-up The intake air amount is adjusted by closing the main throttle valve from the state when the motor is not driven to the target opening.

  In view of this, the invention according to claim 5 is such that the sub-throttle valve is held at a position that is more open than the opening required for idle control after warming up of the internal combustion engine when the motor is not driven. When the opening / closing control means starts driving the motor, the opening degree of the sub-throttle valve is controlled to close the main throttle valve to a target opening degree set according to the temperature of the internal combustion engine. To do. Further, the output control means implements output restriction of the internal combustion engine when restarting the internal combustion engine after warming up, and implements output restriction of the internal combustion engine other than during restarting after warming up the internal combustion engine. do not do. According to this, since the output restriction of the internal combustion engine is performed at the restart after the warm-up of the internal combustion engine in the above configuration, it is possible to prevent the over-rotation of the internal combustion engine from occurring at the warm-up restart. In addition, when the internal combustion engine has not been warmed up, the output restriction is not performed, so that the engine stall can be avoided.

  In addition, when an abnormality such as a motor failure or sticking of the sub throttle valve has occurred, the sub throttle valve cannot be driven, so that the main throttle valve cannot be driven via the interlock mechanism during no-load operation of the internal combustion engine. . Therefore, it is conceivable that the main throttle valve cannot be closed to the target opening degree when the internal combustion engine is decelerated, and as a result, a deceleration failure of the internal combustion engine occurs. In view of this point, the invention according to claim 6 is the case where the output control means cannot control the drive of the sub-throttle valve, and the sub-throttle valve drive abnormality occurs during deceleration of the internal combustion engine. If so, the output of the internal combustion engine is limited. According to this configuration, since the output restriction of the internal combustion engine is performed when a sub-throttle valve drive abnormality occurs during deceleration of the internal combustion engine, the internal combustion engine can be decelerated quickly.

  The invention according to claim 7 is applied to an internal combustion engine including an ignition device and a fuel injection valve, and the output control means uses the ignition device to retard the ignition timing and the fuel injection as an output limit of the internal combustion engine. At least one of reduction of the number of times of fuel injection by the valve is performed. According to this configuration, in order to limit the output of the internal combustion engine by ignition retard and fuel injection decimation, the output limit can be adjusted relatively easily by increasing or decreasing the ignition retard amount and changing the number of injection decimation. Can do.

(First embodiment)
Hereinafter, a first embodiment of a control device for an internal combustion engine according to the present invention will be described with reference to the drawings. The control device in the present embodiment constructs an engine control system for a motorcycle single-cylinder gasoline engine. In the control system, an electronic control unit (hereinafter referred to as ECU) is used as a center to control the fuel injection amount and ignition timing.

  FIG. 1 shows a system configuration diagram of an engine control system 10 in the present embodiment. The engine in the control system 10 is configured as a spark ignition engine. In the engine, an air cleaner 12 is provided at the most upstream portion of the intake pipe 11, and a throttle valve is provided downstream of the air cleaner 12. Two throttle valves are provided side by side in the air flow direction. Among them, a sub-throttle valve 14 whose opening is adjusted by the motor 13 is provided as an upstream throttle valve, and a main throttle valve 15 whose opening is adjusted by a driver's accelerator operation is provided as a downstream throttle valve. It has been. The openings of the main throttle valve 15 and the sub throttle valve 14 are detected by a main throttle opening sensor 16 and a sub throttle opening sensor 17, respectively.

  The engine also includes an electromagnetically driven fuel injection valve 18 that injects and supplies fuel. The fuel from the fuel injection valve 18 is introduced into the cylinder while being mixed with air in the intake pipe. Further, the engine is provided with a spark plug 19. A high voltage is applied to the spark plug 19 at a desired ignition timing through an ignition device (not shown) including an ignition coil. By applying this high voltage, a spark discharge is generated between the opposing electrodes of the spark plug 19, and the air-fuel mixture introduced into the combustion chamber is ignited and used for combustion.

  In addition, this system is provided with a permanent magnet type AC generator (ACG) 21. The ACG 21 is an AC magnet type, and includes a rotor 22 made of a permanent magnet that rotates together with a crankshaft as an output shaft of the engine, and a stator 23 made of a single-phase power generating coil disposed inside the rotor 22. The stator 23 induces an alternating voltage as the crankshaft of the engine rotates, and after rectifying the induced alternating voltage, various electric loads such as the fuel injection valve 18, the ignition device, the motor 13, etc. The ECU 30 is supplied without a battery. The electromotive force Vg of the ACG 21 is detected by the voltage sensor 24.

  Here, in the present embodiment, the fuel injection valve 18 and the ignition device among the ECU 30 and the electric load are activated or driven at a first voltage value V1 (for example, 5 V) or more. On the other hand, the motor 13 is driven at a second voltage value V2 (for example, 12V) or higher on the higher voltage side than the first voltage value V1.

  The engine is also provided with a coolant temperature sensor 25 that detects the coolant temperature and a crank angle sensor 26 that outputs a rectangular crank angle signal for each predetermined crank angle of the engine. In addition, this system is provided with an ignition switch 27 for starting the system, an accelerator opening sensor 28 for detecting an accelerator operation amount by a driver, a shift position sensor 29 for detecting a shift position of the transmission, and the like. Yes.

  As is well known, the ECU 30 is mainly composed of a microcomputer (hereinafter referred to as a microcomputer) 31 composed of a CPU, ROM, RAM, etc., and executes various control programs stored in the ROM, so that the engine operation state can be changed each time. Various control of the engine is executed accordingly. That is, the microcomputer 31 of the ECU 30 inputs detection signals from the various sensors described above and calculates the target throttle opening, fuel injection amount, ignition timing, etc. based on the various detection signals, and the motor 13 and fuel The drive of the injection valve 18 and the ignition device is controlled.

  Next, the main throttle valve 15 and the sub throttle valve 14 will be described in detail. FIG. 2 is an explanatory diagram of the configuration and operation of the main throttle valve 15 and the sub throttle valve 14. 2A shows a state when the engine is stopped (initial state), and FIG. 2B shows a state when the engine is started.

  As shown in FIG. 2A, the main throttle valve 15 is attached to a rotary shaft 41 that is rotatable with respect to the intake pipe 11. Further, the main throttle valve 15 is held in an open state by a predetermined opening (idle upper limit opening TAo) required for first idle when the engine is stopped (that is, the accelerator operation amount is zero). On the other hand, it can be rotated on both sides. In the present embodiment, the idle upper limit opening degree TAo is set based on the first idle at the time of engine cold start. A pulley (not shown) is provided at one end of the rotating shaft 41. When this pulley is operated in conjunction with the driver's accelerator operation, the rotating shaft 41 is rotated, and the main throttle valve 15 is opened and closed with the rotation.

  On the other hand, as shown in FIG. 2A, the sub-throttle valve 14 is attached to a rotary shaft 42 provided on the upstream side of the main throttle valve 15, and is kept fully open when the engine is stopped. Since the system 10 of this embodiment is not provided with a battery, the motor 13 cannot be driven immediately after the engine is started. Therefore, the intake throttle passage is always secured by opening the sub throttle valve 14 when the engine is stopped and further opening the main throttle valve 15 by the idle upper limit opening TAo. The motor 13 is connected to one end of the rotating shaft 42. When the motor 13 is driven based on a command signal from the ECU 30, the rotating shaft 42 rotates, and the sub-throttle valve 14 opens and closes with the rotation.

  The main throttle valve 15 is provided with a link mechanism 43 that opens and closes the main throttle valve 15 in conjunction with the sub throttle valve 14 during no-load operation. The link mechanism 43 adjusts the amount of air introduced into the combustion chamber when the engine is started, and controls the idle rotation speed.

  Specifically, as a control of the idling speed, immediately after the start of the engine, as shown in FIG. 2 (a), the main throttle valve 15 is opened by the idling upper limit opening degree TAo. 14 is in a fully open state. In the present system 10, since the idle upper limit opening degree TAo is set based on the first idle at the time of cold start, for example, the amount of air introduced into the combustion chamber becomes excessive after the engine is warmed up. It is conceivable that the idle rotation speed exceeds the target value. Therefore, in order to set the idle rotation speed to the target value, the motor 13 is driven to rotate the sub-throttle valve 14 in the closing direction. Then, as shown in FIG. 2B, the link mechanism 43 rotates the main throttle valve 15 in the closing direction, and the opening of the main throttle valve 15 is reduced. Thus, the amount of air passing through the main throttle valve 15 is adjusted by adjusting the opening of the sub-throttle valve 14, and as a result, the idle rotation speed is controlled to an appropriate value.

  Here, at the time of starting the engine, it is conceivable that a period during which the sub-throttle valve 14 cannot be driven due to insufficient voltage is generated although the combustion of the engine is started as the ECU 30 is started. This will be described with reference to FIG.

  FIG. 3 is a time chart showing changes in the electromotive force Vg of the ACG 21 and the engine speed during the engine start period. In FIG. 3, as the ignition switch 27 is switched from OFF to ON, the engine rotation speed increases, and thereby the electromotive force Vg of the ACG 21 increases. When the electromotive force Vg reaches the first voltage value V1, the ECU 30 is activated. Further, as the ECU 30 is activated, fuel injection and ignition are started, and combustion is started in the engine. When the engine speed further increases due to the start of combustion and the electromotive force Vg reaches the second voltage value V2, the motor 13 of the sub-throttle valve 14 is driven, and the idling speed is controlled.

  However, during the period from the time when the electromotive force Vg becomes the first voltage value V1 (time B in FIG. 3) to the time when the electromotive force Vg becomes the second voltage value V2 (time C in FIG. 3), the electromotive force Vg is Since the drive voltage of the motor 13 (V2 in this embodiment) has not been reached, the sub-throttle valve 14 cannot be driven. Therefore, the opening degree of the main throttle valve 15 cannot be controlled using the link mechanism 43 even though the engine is combusting. In such a case, since the main throttle valve 15 is held at the idle upper limit opening degree TAo with the sub-throttle valve 14 fully opened, a necessary amount of air is introduced into the combustion chamber at the cold start. Therefore, for example, when the engine is at a relatively high temperature, such as when the engine is restarted after warming up, the air amount is excessive, and it is conceivable that the engine will overspeed during idle control, as indicated by A in FIG.

  Therefore, in the present embodiment, when the opening / closing of the sub-throttle valve 14 cannot be controlled in the idle control at the time of starting the engine, the engine output is limited by retarding the ignition timing. This prevents the idle rotation speed from increasing excessively. As this process, the ECU 30 executes the following process.

  FIG. 4 is a flowchart showing an example of a processing procedure of a process related to output restriction at the time of engine start (startup output restriction process). This process is repeatedly executed at predetermined intervals by the ECU 30 when the electromotive force Vg of the ACG 21 reaches the first voltage value V1 and the ECU 30 is activated.

  In step S10 of FIG. 4, first, based on the shift position of the transmission detected by the shift position sensor 29, the engine speed detected by the crank angle sensor 26, etc., it is determined whether or not idle control is being performed. If it is during idle control, it will progress to step S11 and it will be determined whether the electromotive force Vg detected by the voltage sensor 24 is less than 2nd voltage value V2. If the electromotive force Vg is less than the second voltage value V2, the process proceeds to step S12 to determine whether or not the engine is restarted after warming up. In the present embodiment, when the starting water temperature THW is equal to or higher than a predetermined temperature THWth (for example, 60 ° C.), it is determined that the engine is restarted after warming up. In addition to the above, restarting after engine warm-up may be determined based on, for example, the elapsed time since engine stop.

  If the starting water temperature THW is lower than the predetermined temperature THWth, the process proceeds to step S14, and ignition is performed at the normal ignition timing calculated based on the engine operating state. On the other hand, when the starting water temperature THW is equal to or higher than the predetermined temperature THWth, the process proceeds to step S13, and the ignition retard amount KB is calculated.

  In the present embodiment, the ignition retard amount KB is calculated based on the starting water temperature THWo and the engine speed NE. Specifically, a value obtained by adding the ignition delay amount KB1 calculated based on the starting water temperature THWo and the ignition delay amount KB2 calculated based on the engine speed NE is set as the ignition delay amount KB.

  FIG. 5 shows a map for setting the ignition retard amount KB. In FIG. 5, (a) is a map showing the relationship between the starting water temperature THWo and the ignition retard amount KB1, and (b) is a map showing the relationship between the engine speed NE and the ignition retard amount KB2. . As shown in FIG. 5 (a), the ignition retard amount KB1 calculated based on the starting water temperature THWo is larger as the starting water temperature THWo is higher in the range where the starting water temperature THW is equal to or higher than the temperature TWHth. . Further, as shown in FIG. 5B, the ignition retard amount KB2 calculated based on the engine rotational speed NE is set to a larger value as the engine rotational speed NE is higher until the engine rotational speed is NE1. When the rotational speed is NE1 or higher, it is fixed at the maximum value. A value obtained by adding the ignition retardation amounts KB1 and KB2 calculated from these maps is used as the ignition retardation amount KB.

  Returning to the description of FIG. 4, in the following step S14, the ignition timing is retarded by the calculated ignition retard amount KB, and the ignition control is performed. Thereby, engine output is suppressed. In this embodiment, when the starting water temperature THW is lower than the predetermined temperature TWHth, engine stall is likely to occur. Therefore, in order to avoid this, the ignition delay is not performed even during idle control. .

  On the other hand, when the electromotive force Vg of the ACG 21 becomes equal to or higher than the second voltage value V2 during idle control, a negative determination is made in step S11, and the process proceeds to step S15 to determine whether or not the ignition timing is retarded. If the ignition retard is being performed, the process proceeds to step S16, and the ignition retard amount KB is calculated. Here, in order to gradually return the ignition timing to the normal value, the current value KBn is a value obtained by subtracting the predetermined amount ART from the previous value KBn−1 of the ignition retard amount KB. Then, the process proceeds to step S14, and ignition control is performed by retarding the ignition timing by the calculated ignition retard amount KB.

  If it is detected that the accelerator is operated after the engine is started, a negative determination is made in step S10 because the idle control is not being performed, and the routine proceeds to step S15, where the ignition retard amount KB is reset or ignition control is performed. carry out. If the engine is stopped, the routine is terminated without performing ignition in step S14.

  FIG. 6 is a time chart for explaining the start-time output restriction process. In FIG. 6, the solid line indicates a case where the ignition delay is performed when the engine is started, and the alternate long and short dash line indicates a case where the ignition delay is not performed when the engine is started.

  In FIG. 6, when the electromotive force Vg of the ACG 21 reaches the first voltage value V1, the ECU 30 is started, and fuel injection and ignition are started accordingly. At this time, since the electromotive force Vg is less than the drive voltage (second voltage value V2) of the motor 13, the sub-throttle valve 14 cannot be driven, and the intake air amount at the time of first idling cannot be adjusted. . Therefore, in the ignition control after the electromotive force Vg reaches the first voltage value V1, the ignition timing is retarded as a process for limiting the engine output. Specifically, the ignition delay amount KB1 calculated based on the starting water temperature THWo is used as the initial value of the ignition delay amount KB, and the ignition delay amount KB is increased as the engine speed increases. As a result, as shown by a solid line in FIG. 6, an excessive increase in the idle rotation speed is suppressed in the first idle.

  When the electromotive force Vg reaches the second voltage value V2, the motor 13 of the sub-throttle valve 14 is driven to rotate the sub-throttle valve 14 in the closing direction. Further, in conjunction with the sub-throttle valve 14, the main throttle valve 15 is rotated in the closing direction to the target throttle opening degree TAtg via the link mechanism 43. As a result, the intake air amount can be controlled, and the idle rotation speed can be controlled. Further, the ignition retard amount KB is gradually reduced when the electromotive force Vg reaches the second voltage value V2, and returned to the normal ignition timing.

  According to the first embodiment described above, the following excellent effects can be obtained.

  A configuration in which ignition delay is performed as a process for limiting engine output when the ACG 21 generates power when the engine is started and the electromotive force Vg is equal to or higher than the first voltage value V1 and lower than the second voltage value V2. Therefore, when the intake air amount at the time of idling cannot be adjusted despite the combustion being performed in the engine, it is possible to suppress an excessive increase in the idling rotational speed. Thereby, the engine rotation speed in an idle state can be suitably controlled.

  In the present system 10, no battery is provided, and the driving voltage of the fuel injection valve 18 and the ignition device and the driving voltage of the motor 13 are set to different values, so that during fuel injection and ignition during engine start-up. Where a period during which the sub-throttle valve 14 cannot be driven is likely to occur, the above configuration can advantageously obtain an effect of preventing over-rotation during idle control.

  Further, since the battery is not provided, in order to secure the intake passage immediately after the ignition is turned on, the sub throttle valve 14 is fully opened and the main throttle valve 15 is set as the initial state of the throttle valves 14 and 15. In this state, the intake air amount during idle control is adjusted by turning the main throttle valve 15 in the closing direction. For this reason, the idle rotation speed is likely to increase excessively during a period in which the motor 13 cannot be driven when the engine is started. By performing the ignition delay during the same period, it is possible to prevent over-rotation from occurring during idle control. .

  When the electromotive force Vg of the ACG 21 reaches the second voltage value V2 and thereby the sub-throttle valve 14 is driven, the ignition retard amount KB is gradually reduced. It can be avoided that the speed becomes excessively small. As a result, engine stall can be prevented. Further, by gradually reducing the ignition retard amount KB, it is possible to avoid a sudden change in the idle rotation speed.

  After the engine is warmed up, the idling engine speed is likely to increase compared to that at the time of cold start. However, since the ignition retard is implemented at the time of restart after the engine is warmed up, the main throttle valve 15 is linked by the link mechanism 43. The engine overspeed due to the fact that the engine cannot be controlled in the closing direction can be suitably suppressed. Further, since the ignition delay is not performed when the engine is not warmed up, the engine stall due to the ignition delay can be avoided.

  Since the ignition retard is implemented as a process for limiting the engine output, the idle rotation speed can be adjusted relatively easily by increasing or decreasing the ignition retard amount KB. Further, since the ignition retard amount KB is calculated based on the starting water temperature THWo and the engine speed NE, the ignition retard amount KB is set to an appropriate value in accordance with the starting water temperature THWo and the engine speed NE. As a result, the idle rotation speed can be controlled to an appropriate value.

(Second Embodiment)
Next, a second embodiment of the present invention will be described focusing on differences from the first embodiment. In the present embodiment, during engine operation, when the sub-throttle valve 14 cannot be driven due to, for example, a malfunction of the motor 13 or valve sticking, the ignition timing is retarded or the fuel is reduced as a process for limiting the engine output. Implement injection thinning.

  Specifically, when the sub-throttle valve 14 cannot be driven due to a failure of the motor 13 or the like, the opening adjustment of the main throttle valve 15 by the link mechanism 43 cannot be performed. That is, the opening of the main throttle valve 15 (main throttle opening) cannot be made smaller than the idle upper limit opening TAo. Therefore, for example, when the accelerator is fully closed as an operation for decelerating while the vehicle is running, the air amount cannot be further reduced from the value corresponding to the idle upper limit opening TAo, resulting in poor deceleration. It is possible. Therefore, in this embodiment, when the vehicle is decelerating and the sub-throttle valve 14 cannot be driven, ignition retard or injection thinning is performed as a process for limiting the engine output.

  FIG. 7 is a flowchart illustrating an example of a processing procedure of processing related to engine output restriction (abnormal output restriction processing) when the operation of the sub-throttle valve 14 is abnormal. This process is repeatedly executed by the ECU 30 at a predetermined cycle.

  In step S20 in FIG. 7, it is first determined whether or not a drive abnormality has occurred such that the sub-throttle valve 14 cannot be driven. The drive abnormality of the sub-throttle valve 14 is detected based on, for example, the deviation between the sub-throttle opening detected by the sub-throttle opening sensor 17 and the target value. If the sub-throttle valve 14 cannot be driven, the process proceeds to step S21 to determine whether or not the vehicle is decelerating. In the present embodiment, it is detected by the accelerator opening sensor 28 that the accelerator is switched from the accelerator-on state to the accelerator-off state, and the main throttle opening sensor 16 is set to a predetermined opening α that is higher than the idle upper limit opening TAo by the main throttle opening sensor 16. It is determined that the vehicle is decelerating when the opening degree is less than or equal to the large opening TAL.

  If the vehicle is decelerating, the process proceeds to step S22, and it is determined whether or not the engine rotation speed is equal to or higher than the high rotation determination value NEH. If the engine rotation speed is equal to or higher than the high rotation determination value NEH, the process proceeds to step S23, and the combustion control is performed by thinning out the fuel injection as a process for limiting the engine output. At this time, it is desirable to increase the number of thinnings as the engine speed increases.

  On the other hand, if the engine rotation speed is less than the high rotation determination value NEH, the process proceeds to step S24, and it is determined whether the engine rotation speed is equal to or higher than the medium rotation determination value NEM. The medium rotation determination value NEM is set on the lower rotation side than the high rotation determination value NEH. If it is equal to or greater than the medium rotation determination value NEM, the ignition control is performed by retarding the ignition timing as a process for limiting the engine output. At this time, it is desirable to increase the retard amount as the engine speed increases.

  According to the second embodiment described above, the following excellent effects can be obtained.

  Since the engine output is limited when the accelerator is turned off as an operation for decelerating the vehicle and the drive abnormality of the sub-throttle valve 14 occurs, the main throttle valve 15 can be rotated via the link mechanism 43. Therefore, even when the intake air amount cannot be further reduced, the vehicle can be quickly decelerated.

  As a process for limiting the engine output, when the engine speed is higher than the high engine speed determination value NEH, injection thinning is performed, and when the engine speed is equal to or higher than the medium engine speed determination value NEM and less than the high engine speed determination value NEH. Therefore, the engine output can be limited according to the engine speed. That is, when the engine speed is in the high speed range, it is necessary to reduce the engine output more greatly, and therefore the engine output is limited by thinning out the injection. On the other hand, when the engine rotation speed is in the middle rotation range, the engine output to be reduced is smaller than that in the high engine rotation range, and therefore the engine output is limited by the ignition delay angle. By doing so, the engine output is limited in a form corresponding to the engine rotation speed, so that the vehicle can be quickly decelerated while preventing a sudden change in the engine rotation speed.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be implemented as follows, for example.

  In the first embodiment, the configuration is described in which the ignition timing is retarded in a period in which the sub-throttle valve 14 cannot be driven because the drive voltage of the motor 13 is not satisfied when the engine is started. The ignition timing may be retarded when the sub-throttle valve 14 cannot be driven due to a failure in the engine. Even in this case, the opening degree of the main throttle valve 15 cannot be adjusted by the link mechanism 43 when the engine is started, and therefore it is conceivable that the idle rotation speed increases excessively. Therefore, it is possible to obtain an effect of suitably controlling the idle rotation speed by retarding the ignition timing when starting the engine when a motor failure or the like occurs.

  In the first embodiment, the ignition timing is retarded as a process for limiting the engine output. However, the process for limiting the engine output is not limited to this. For example, fuel injection thinning is performed. It is good also as a structure which implements or reduces the amount of fuel injection.

  -In the said 2nd Embodiment, you may apply this invention to the vehicle of a structure provided with a battery. Even in the case of a vehicle equipped with a battery, when the main throttle valve 15 and the sub throttle valve 14 having the same configuration as that of the above embodiment are provided, an operation abnormality of the sub throttle valve 14 occurs, so that the second This is because the same can be said for the embodiment.

  In the above embodiment, the opening of the main throttle valve 15 is rotated in the closing direction via the link mechanism 43 by rotating the sub-throttle valve 14 from the fully open state to the closing direction. As long as 15 can be turned in the closing direction, the opening degree and the turning direction of the sub-throttle valve 14 in the initial state are not particularly limited. For example, the position of the sub throttle valve 14 in the closed state with respect to the fully opened state is set to the initial state, and the sub throttle valve 14 is rotated in the opening direction, whereby the main throttle valve 15 is rotated in the closing direction via the link mechanism 43. It is good also as a structure. In the above-described embodiment, the initial state of the main throttle valve 15 is set to be held at the opening degree (idle upper limit opening degree TAo) determined based on the idle control at the time of cold start. For example, it is good also as a structure hold | maintained in the intermediate position of full open position or a full open position, and idle upper limit opening degree TAo.

  -Although it applied to the single cylinder engine in the said embodiment, the number of cylinders of an engine is not limited to this. For example, the present invention may be applied to a multi-cylinder engine such as a 4-cylinder engine. In this embodiment, the present invention is applied to a motorcycle, but may be applied to an automobile.

The system block diagram of an engine control system. Explanatory drawing about a structure and operation | movement of a main throttle valve and a sub throttle valve. The time chart which shows transition of the electromotive force Vg, an engine speed, etc. in an engine starting period. The flowchart which shows an example of the process sequence of the output restriction process at the time of starting. A map for setting the ignition retard amount. The time chart for demonstrating the output limitation process at the time of a start. The flowchart which shows an example of the process sequence of an output control process at the time of abnormality.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine control system, 13 ... Motor, 14 ... Sub throttle valve, 15 ... Main throttle valve, 16 ... Main throttle opening sensor, 17 ... Sub throttle opening sensor, 21 ... Alternator (ACG), 30 ... ECU , 31... Microcomputer, 43... Link mechanism as an interlocking mechanism.

Claims (7)

A main throttle valve that opens and closes the intake passage in conjunction with an accelerator operation by the driver, a sub-throttle valve that opens and closes the intake passage by driving a motor, and an opening direction or a closing direction of the sub-throttle valve in a no-load operation state Applied to an internal combustion engine comprising an interlocking mechanism that closes the main throttle valve in conjunction with the movement to
Open / close control means for controlling the opening / closing of the sub-throttle valve by driving the motor;
Output control means for limiting the output of the internal combustion engine when the internal combustion engine is in a no-load operation state and the opening / closing control means cannot control the driving of the sub-slot valve;
A control device for an internal combustion engine, comprising: Applied to an internal combustion engine in which fuel injection and ignition are carried out by power feeding from a generator rotating in synchronization with the output shaft of the internal combustion engine and the motor is driven,
A control device for an internal combustion engine that performs fuel injection and ignition when a voltage supplied from the generator is equal to or higher than a first voltage value;
The open / close control means controls the driving of the sub-throttle valve by driving the motor when the voltage supplied from the generator becomes equal to or higher than a second voltage value higher than the first voltage value. ,
In the case where the output control means cannot control the driving of the sub-throttle valve and the voltage supplied from the generator is equal to or higher than the first voltage value and lower than the second voltage value, the internal combustion engine The control apparatus for an internal combustion engine according to claim 1, wherein the output is limited.   The control device for an internal combustion engine according to claim 2, wherein fuel injection and ignition are performed by directly supplying power from the generator without going through a power storage device, and the motor is driven.   4. The control device for an internal combustion engine according to claim 1, wherein the output control unit releases the output restriction of the internal combustion engine when driving of the sub-throttle valve is started. 5. The sub-throttle valve is held at a position more open than the opening required for idle control after warm-up of the internal combustion engine when the motor is not driven,
The opening / closing control means controls the opening of the sub-throttle valve to close the main throttle valve to a target opening that is set according to the temperature of the internal combustion engine when driving of the motor is started. ,
The output control means implements output restriction of the internal combustion engine when the internal combustion engine is restarted after warming up, and does not implement output restriction of the internal combustion engine except during restart after the internal combustion engine is warmed up. Item 5. The control device for the internal combustion engine according to any one of Items 1 to 4.   The output control means limits the output of the internal combustion engine when the drive of the sub-throttle valve cannot be controlled and when the internal throttle engine is decelerated and when the drive abnormality of the sub-throttle valve has occurred. The control device for an internal combustion engine according to any one of claims 1 to 5. Applied to an internal combustion engine comprising an ignition device and a fuel injection valve;
7. The output control means according to any one of claims 1 to 6, wherein at least one of retarding the ignition timing by the ignition device and reducing the number of times of fuel injection by the fuel injection valve is implemented as output limitation of the internal combustion engine. The control apparatus of the internal combustion engine described in 1.

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