JP2011208588A - Method of controlling internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the number of executions of idling stop control as many as possible, while ensuring educational opportunity of valve opening for controlling the number of idling rotations.SOLUTION: An internal combustion engine includes an idling stop function of stopping the idling of the internal combustion engine when a predetermined stop condition is established; and automatically restarting the internal combustion engine when a predetermined restart condition is established. The internal combustion engine learns the valve opening for controlling the number of idling rotations when a predetermined educational execution condition is established during the idling of the internal combustion engine. In a method of controlling the internal combustion engine, one of the stop conditions includes the passage of a predetermined period of time from the establishment of the predetermined educational execution condition during the idling of the internal combustion engine.

Description

  The present invention relates to a control method for an internal combustion engine having an idling stop function.

  Conventionally, it is well known to learn an opening value of an electronic throttle valve or an ISC valve during idling for the purpose of constantly maintaining the idling speed of an internal combustion engine at a required target speed. This focuses on the point that deposits adhere to an electronic throttle valve or the like with aging, and the amount of intake air with respect to the valve opening decreases. The learning of the valve opening during idle speed control is performed by operating an electronic throttle valve or the like when a predetermined learning execution condition is satisfied, and the opening when the measured engine speed is stabilized near the target idle speed. Do by remembering. The learned value of the valve opening is used for subsequent idle speed control.

  On the other hand, when the vehicle is stopped (ie, the vehicle speed is 0), the brake pedal is depressed, and the battery voltage is equal to or higher than a predetermined value, the internal combustion engine is idled in order to improve fuel consumption. It is also becoming popular to perform idle stop control to stop.

  When the idling stop control is performed, the number of times that the idling of the internal combustion engine occurs is inevitably reduced, so that the number of executions of learning of the valve opening described above is also reduced. Then, correction of the valve opening degree with respect to adhesion of the deposit to the valve is not performed over a long period of time. For this reason, the intake air amount is insufficient and the rotational speed of the internal combustion engine during idling becomes unstable.

  In order to solve this problem, in an internal combustion engine that performs idling stop, a method is considered in which idling is maintained without idling stop until learning of the valve opening described above is completed (for example, patents). Reference 1).

  Learning the valve opening for idle speed control takes a long time to complete if the auxiliary load is not stable during the learning. For example, if an air conditioner, a light, or the like is operated during learning, the auxiliary machine load fluctuates and the engine speed does not easily converge to the target idle speed. When the method described in Patent Document 1 is adopted, especially in summer and winter when the air conditioner is always operated, learning is not completed between the stop of the vehicle and the restart, and the opportunity for idling stop is lost. As a result, it becomes difficult to obtain the effect of improving fuel consumption.

Japanese Patent No. 3969365

  An object of the present invention is to increase the number of times that the idle stop control is performed as much as possible while ensuring the opportunity to learn the valve opening for controlling the idle speed.

  In other words, the idling stop control method for an internal combustion engine according to the present invention stops idling of the internal combustion engine when a predetermined stop condition is satisfied, and automatically restarts the internal combustion engine when the predetermined restart condition is satisfied. A control method for an internal combustion engine that includes a stop function and that further learns a valve opening for idle speed control when a predetermined learning execution condition is satisfied during idling of the internal combustion engine, One of the characteristics is that a predetermined time has elapsed since a predetermined learning execution condition was satisfied during idling of the internal combustion engine.

  Here, the “valve opening” includes not only the opening of the electronic throttle valve but also an ISC bypass passage that bypasses the throttle valve, and an ISC that controls the intake air amount during idle operation in the ISC bypass passage. It includes the overall opening of a valve in a passage for supplying air during idling of the internal combustion engine, such as an ISC valve in an internal combustion engine provided with a valve (idle speed control valve).

  If this is the case, the learning execution condition is satisfied even if the auxiliary load is not stable during learning of the valve opening for idle speed control and it takes a long time to complete the learning. Since the idling of the internal combustion engine is stopped when a predetermined time elapses, the number of times that the idle stop control is performed can be increased.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to increase the frequency | count that idle stop control is performed as much as possible, ensuring the learning opportunity of the valve opening degree for idle speed control.

1 is a schematic configuration explanatory diagram of an internal combustion engine according to an embodiment of the present invention. The flowchart which shows the control procedure of the embodiment.

  An embodiment of the present invention will be described with reference to the drawings.

  The internal combustion engine 100 is a spark ignition type for automobiles and has a plurality of cylinders. FIG. 1 representatively shows the configuration of one cylinder.

  An electronic throttle valve 2 is disposed in the intake system 1 of the internal combustion engine 100, and a surge tank 3 is disposed downstream thereof. A fuel injection valve 4 is attached downstream of the surge tank 3. The cylinder head 6 that forms the combustion chamber 5 is provided with an intake valve 7 and an exhaust valve 8 and an ignition plug 9 that generates a spark. The electronic throttle valve 2, the fuel injection valve 4, and the spark plug 9 are controlled by the electronic control device 10. The opening degree of the electronic throttle valve 2 is normally controlled in accordance with the operation amount (depression degree) of the accelerator pedal, but may be controlled regardless of the operation amount of the accelerator pedal during idling or the like.

The exhaust system 11 of the internal combustion engine 100 is provided with a three-way catalyst 13 as a catalyst in an exhaust pipe 12 leading to a muffler (not shown), and a signal corresponding to the oxygen concentration in the exhaust gas is sent to the electronic control unit 10. Is attached with an O ₂ sensor 14.

The electronic control device 10 is a microcomputer system including a CPU 10a, a RAM 10b, a ROM 10c, a flash memory 10d, an I / O interface 10e, and the like. The I / O interface 10e has an intake pressure signal a output from an intake pressure sensor 15 that detects the pressure in the surge tank 3 constituting the intake system 1, and a rotation for detecting the engine speed including the idling speed. A rotational speed signal b output from the number sensor 16, a vehicle speed signal c output from the vehicle speed sensor 17 for detecting the vehicle speed, and an opening output from the throttle sensor 18 for detecting the opening state of the electronic throttle valve 2. A degree signal d, a water temperature signal e output from a water temperature sensor 19 for detecting the coolant temperature of the engine as a temperature of the internal combustion engine 100, an accelerator signal f output from an accelerator sensor 20 for detecting an operation amount of an accelerator pedal, The brake signal g output from the brake sensor 21 that detects the amount of brake operation, and the voltmeter 22 that detects the battery voltage Battery voltage signal h outputted, the signal i or the like from the O ₂ sensor 14 are inputted. Further, from the I / O interface 10e, an opening degree control signal p for opening and closing the electronic throttle valve 2 is a valve opening drive signal corresponding to the fuel injection time calculated for the fuel injection valve 4. q and an ignition signal r are output to the spark plug 9, respectively. Various control programs are stored in the ROM 10c or the flash memory 10d, and the programs are read into the RAM 10b and decoded by the CPU 10a. The electronic control device 10 performs control of the intake air amount, control of the fuel injection amount, control of the ignition timing, and the like according to the program.

  The electronic control unit 10 performs idle speed control for maintaining the engine speed at a required idle speed during idling. Further, when a predetermined learning execution condition is satisfied during idling, learning of the throttle valve opening for idle speed control is performed.

  The learning execution condition includes a condition that the vehicle speed is 0, the cooling water temperature is equal to or higher than a predetermined threshold value, and the engine speed is within a certain idling range (near the target idle speed). . In the present embodiment, the learning execution condition does not include a condition in which the auxiliary machine load applied to the internal combustion engine 100 fluctuates when operated by the user. That is, it does not include electric loads such as the operating state of the air conditioner, blower, defogger, etc., and the lighting state of the light.

  Learning of the opening degree of the electronic throttle valve 2 is performed by operating the electronic throttle valve 2 during idling and storing the opening degree when the actually measured engine speed is stabilized near the target idle speed as a learned value. The stored learned value of the throttle valve opening is used for subsequent idle speed control. In the present embodiment, learning of the throttle valve opening is performed once in a period (one trip) from when the ignition switch is turned on to when the ignition switch is turned off.

  In addition, the electronic control device 10 stops idling of the internal combustion engine 100 when a predetermined stop condition is satisfied, and automatically stops the internal combustion engine 100 when a predetermined restart condition is satisfied. To implement. The program for idle stop control is executed every time a predetermined stop condition is satisfied.

  The stop conditions include at least that the operation amount of the accelerator pedal is 0 (not depressed), the operation amount of the brake pedal is not 0 (depressed), and the battery voltage is equal to or higher than a predetermined value. included. In addition, in this embodiment, learning of the throttle valve opening for idle speed control has been completed at least once since the ignition switch was last turned on, or predetermined learning is executed during idling. The idling is stopped on the condition that a predetermined time has passed after the condition is established. The predetermined time is set to 30 seconds, for example. This is based on the fact that the learning of the throttle valve opening is completed in several seconds to 30 seconds if there is no change in auxiliary load that is not easily estimated by the user's operation. In other words, the predetermined time corresponds to the maximum time (estimated value) required to complete learning under the condition that the air conditioner, the blower, the defogger, the light, etc. are not operating.

  Hereinafter, the procedure of processing executed by the electronic control unit 10 according to a program for idle stop control during idling of the internal combustion engine 100 will be described with reference to FIG.

  In step S1, it is determined whether or not learning of the throttle valve opening for idle speed control has already been completed at least once since the ignition switch was last turned on (that is, during the same trip). If the learning has been completed once or more, the process proceeds to step S6. If learning has not been completed, the process proceeds to step S2.

  In step S2, it is determined whether or not a learning execution condition for the throttle valve opening is satisfied. If the learning execution condition is satisfied, the process proceeds to step S3.

  In step S3, the throttle valve opening is learned. In this learning, the electronic throttle valve 2 is opened or closed in order to reduce the difference between the measured engine speed and the target idle speed, and the measured engine speed converges near the target idle speed and stabilizes. wait.

  In step S4, it is determined whether or not learning of the throttle valve opening is completed. That is, it is determined whether or not the actually measured engine speed has stabilized near the target idle speed and the throttle valve opening at that time has been stored as a learned value. If the learning is completed, the process proceeds to step S6.

  In step S5, it is determined whether or not a predetermined time (30 seconds) has elapsed from the satisfaction of the learning execution condition without completing learning of the throttle valve opening. If the predetermined time has elapsed since the learning execution condition was satisfied, the process proceeds to step S6. Otherwise, it proceeds to step S3 and continues learning.

  In step S6, whether or not other conditions permitting idle stop are satisfied, specifically, the accelerator pedal operation amount is 0, the brake pedal operation amount is not 0, and the battery voltage is predetermined. It is determined whether it is above. If other conditions permitting idle stop are satisfied, the process proceeds to step S7. Otherwise, continue idling.

  In step S7, idling is stopped. The idling stop continues until the restart condition is satisfied.

  When the restart condition is satisfied during the execution of the program for idle stop control described above, control for automatically restarting the internal combustion engine 100 is immediately performed.

  Assuming that other conditions permitting idle stop are satisfied, the operation when the control method of this embodiment is implemented will be described. First, during the first idling operation after the driver inserts the ignition key and turns on the ignition switch, the throttle valve opening degree for idling speed control is always learned. Until this learning is completed, the procedure of steps S1, S2, S3, and S4 is sequentially performed, and the idle operation is continued. When this learning is completed within a predetermined time, that is, within 30 seconds, thereafter, steps S6 → S7 are sequentially performed, and idle stop control is executed. On the other hand, if the learning is not completed within 30 seconds, the procedure of steps S1, S2, S3, S4, and S5 is sequentially performed until 30 seconds elapse after the learning execution condition is satisfied, and the idle operation However, after 30 seconds have elapsed since the learning execution condition is satisfied, steps S6 to S7 are sequentially performed, and the idle stop control is executed.

  If the driver has completed learning of the throttle valve opening during the previous idle operation in the second and subsequent idle operations after turning on the ignition switch, the steps S1 → S6 → S7 are sequentially performed. The idle stop control is executed. If the learning is not yet completed, the idle operation is continued until the learning is completed or until 30 seconds elapses after the learning execution condition is satisfied, as in the first idle operation described in the previous stage. Thereafter, the idle stop control is executed.

  As described above, according to the idling stop control method of the internal combustion engine 100 of the present embodiment, the auxiliary machine is not used, or the auxiliary machine load is stable, and the valve opening degree for idle speed control is controlled. When learning does not require time, the internal combustion engine 100 can be stopped as soon as learning is completed. On the other hand, even in the summer and winter months when the air conditioner is in constant operation, even if the auxiliary load is not stable during learning of the valve opening, it takes a long time to complete the learning. Since the internal combustion engine 100 is stopped after 30 seconds from the establishment, the learning is abandoned and the number of times that the idle stop control is performed can be increased as much as possible. In addition, since learning of the valve opening is attempted regardless of the operation status of the auxiliary machine, a necessary and sufficient learning opportunity can be ensured to effectively solve the problem of insufficient intake air amount due to adhesion of the valve deposit.

  The present invention is not limited to the embodiment described above.

  For example, the present invention may be applied to an internal combustion engine in which an ISC bypass passage that bypasses the throttle valve is provided and an ISC valve that controls the intake air amount is provided in the ISC bypass passage. That is, the idle rotation is performed by operating the ISC valve when a predetermined learning execution condition is satisfied during idling of the internal combustion engine and storing the ISC valve opening when the measured engine rotation speed is stabilized near the target idle rotation speed. In the control method for learning the ISC valve opening for number control, idling of the internal combustion engine is stopped when a predetermined stop condition is satisfied, including a lapse of a predetermined time after the predetermined learning execution condition is satisfied. You may do it.

  In the above embodiment, after completing learning once during one trip, learning is not performed again during the trip, but this is not a limitation. Learning is performed once every predetermined distance, for example, 5000 to 6000 km, and after completing learning once during the traveling, learning is not performed again until the next predetermined distance is entered. Also good.

  In addition, various changes may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Internal combustion engine 10 ... Electronic control unit 20 ... Accelerator sensor 21 ... Brake sensor 22 ... Voltmeter

Claims (1)

An idling stop function for stopping idling of the internal combustion engine when a predetermined stop condition is satisfied, and automatically restarting the internal combustion engine when a predetermined restart condition is satisfied;
Furthermore, a control method for an internal combustion engine that learns a valve opening for idle speed control when a predetermined learning execution condition is satisfied during idling of the internal combustion engine,
One of the stop conditions is
A control method for an internal combustion engine, characterized in that a predetermined time has elapsed since a predetermined learning execution condition was satisfied during idling of the internal combustion engine.

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