JP2010065529A - Control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine capable of suitably making both compatible in reduction in fuel consumption by the automatic stopping-starting function and stabilization of an engine operation state by the learning function. <P>SOLUTION: This device learns a learning value on the suction air volume capable of stably operating the internal combustion engine in idle operation, and adjusts the suction air volume based on the learning value, and has the automatic stopping-starting function of temporarily automatically stopping the internal combustion engine when a predetermined stopping condition including a condition where an engine operation area is a specific operation area containing an idle operation area is realized and restarting the internal combustion engine when a predetermined restarting condition is realized, and executes leaning of the learning value based of this difference ΔGA (S304-S309) by calculating the difference ΔGA from its reference value GATA by detecting the passage intake volume GA in an area except for the specific operation area (S303). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an internal combustion engine control device that performs an automatic stop start function for automatically stopping and starting an internal combustion engine and a learning function for learning an engine control amount that realizes a stable operation during idle operation. .

  In recent years, in order to reduce fuel consumption and emissions, the internal combustion engine is automatically stopped when the vehicle stops traveling at an intersection or the like, and the internal combustion engine is automatically started at an arbitrary timing during the automatic stop. It has been proposed and put to practical use to perform a startable control, so-called automatic stop / start control (see, for example, Patent Document 1).

  In addition, during idling of the in-vehicle internal combustion engine, a target speed is set for the rotational speed of the output shaft (engine rotational speed), and the intake air amount and fuel are set so that the target speed matches the actual engine rotational speed. A so-called idle speed control (ISC) control that feedback-controls an engine control amount such as an injection amount has been put into practical use. In this ISC control, as the target rotational speed, a rotational speed as low as possible is set under the condition that the stable operation of the internal combustion engine during idling operation is maintained. Thereby, engine noise and fuel consumption rate are suppressed as much as possible while maintaining stable operation of the internal combustion engine during idling.

Furthermore, it has also been proposed to execute learning control for learning the engine control amount during execution of ISC control. By using the engine control amount (ISC learned value) learned through this learning control in the idle operation region and other operation regions, the engine control amount can be adjusted with high accuracy regardless of individual differences or changes over time of the internal combustion engine. It becomes like this.
JP 2006-46103 A

  In the internal combustion engine in which the automatic stop / start control is executed, since the operation of the internal combustion engine is automatically stopped in the situation where the engine is idling, the opportunity to learn the ISC learning value through the learning control is very small. There is a risk that the value will be far from the actual value.

  In order to suppress the occurrence of such inconvenience, it is conceivable to periodically learn the ISC learning value after prohibiting the automatic stop of the internal combustion engine by the automatic stop start control. However, in this case, since the opportunity for the internal combustion engine to be automatically stopped is reduced, the effect of reducing the fuel consumption of the internal combustion engine is reduced accordingly.

  Note that the present invention is not limited to a device that performs the ISC control and learning control described above, but a device that performs learning control for learning an engine control amount (learned value) that can stably operate the internal combustion engine during idle operation. If so, these facts are generally common.

  The present invention has been made in view of the above circumstances, and an object thereof is an internal combustion engine capable of achieving both a reduction in fuel consumption by an automatic stop / start function and stabilization of an engine operating state by a learning function. It is to provide an engine control device.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
The invention according to claim 1 is a learning means for learning a learning value for an engine control amount capable of stably operating the internal combustion engine during idle operation, and an adjusting means for adjusting the engine control amount based on the learning value. And when the predetermined stop condition including the condition that the engine operation region is a specific operation region including the idle operation region is satisfied, the internal combustion engine is temporarily automatically stopped and the predetermined restart condition is satisfied. In an internal combustion engine control device comprising an automatic stop / starting means for restarting the internal combustion engine sometimes, it has a detecting means for detecting an actual value of the engine control amount, and the learning means learns the learning value. The gist is to execute based on the degree of deviation between the actual value and a predetermined reference value in a region other than the specific operation region.

  According to the above configuration, the learning value about the engine control amount that can stably operate the internal combustion engine during the idle operation is set to the engine control amount in the region other than the specific operation region, in other words, in the operation region other than the idle operation region. Can learn based on. As a result, it is not necessary to prohibit the automatic stop of the internal combustion engine in order to learn the learning value. Therefore, it is possible to maintain a high frequency of the automatic stop of the internal combustion engine. Can be suitably reduced.

  Moreover, although the learning value is learned based on the engine control amount in a region other than the idle operation region of the internal combustion engine, the same value is obtained based on the degree of deviation between the actual value of the engine control amount and a predetermined reference value. The engine control amount that can suppress the deviation, in other words, the correction amount of the engine control amount suitable for stable operation of the internal combustion engine during idle operation can be obtained, and the learning value can be learned based on this. . Therefore, the engine operating state can be suitably stabilized by the learning function based on the learning value.

  According to a second aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, the control device stores in advance a relationship between an operating state of the internal combustion engine and the reference value, and the learning means The gist is to obtain the reference value from the relationship based on the operating state of the internal combustion engine.

  According to the above configuration, since the reference value is calculated based on the operating state of the internal combustion engine based on a predetermined relationship, the learned value can be learned with high accuracy over a wide operating region.

As the engine control amount, in addition to the fuel injection amount, an intake air amount can be adopted as in claim 3.
Further, the configuration in which the intake air amount is adopted as the engine control amount is applied to an internal combustion engine provided with a throttle valve for changing a passage cross-sectional area of the intake passage as in claim 4, and An air flow meter provided upstream of the throttle valve in the intake flow direction functions as the detection means, and can be applied to a device in which the opening degree of the throttle valve and the engine speed are adopted as the operating state of the internal combustion engine.

  According to a fifth aspect of the present invention, in the control device for an internal combustion engine according to the fourth aspect, the learning means detects the actual condition detected when an execution condition that the opening degree of the throttle valve is smaller than a predetermined opening degree is satisfied. The gist is that the degree of deviation is obtained based on the value and the reference value.

  Normally, when the internal combustion engine is in the idle operation region and when it is in the other operation region, the opening of the throttle valve is set to a different opening, and the engine control amount is adjusted to a different amount. Therefore, as described above, when learning a learning value for an engine control amount capable of stably operating the internal combustion engine during idle operation as described above based on the engine control amount in a region other than the idle operation region, the engine operation region However, there are different areas when the learning value is actually applied (when it is applied) and when the actual value of the engine control amount is detected for learning the learning value (when it is detected). Therefore, due to the difference in the engine operation range, the engine control amount differs between the application time and the detection time, and the learning value is learned based on the engine control amount in the idle operation region. Compared to the case, it can be said that the learning accuracy of the learning value is likely to be lowered.

  In this regard, according to the above configuration, the actual engine control amount detected when the throttle valve opening is smaller than the predetermined opening, in other words, when the difference in the engine control amount due to the difference in the engine operation region is small. The learning value can be learned based on the value, and the learning can be executed with high accuracy.

  According to a sixth aspect of the present invention, in the control device for an internal combustion engine according to any one of the first to fifth aspects, the learning means has the learning value on condition that the degree of deviation is larger than a predetermined value. The gist is to allow the renewal of

  According to the above configuration, the learning value can be updated only when the operation state of the internal combustion engine becomes unstable, and the internal combustion engine can be updated while suppressing the update frequency of the learning value. The instability of the operating state can be suppressed accurately.

  According to a seventh aspect of the present invention, in the control device for an internal combustion engine according to the sixth aspect, the learning means changes the predetermined value by an amount corresponding to the update amount in accordance with the update of the learned value. This is the gist.

  According to the above configuration, after the learning value is once updated to suppress the instability of the operating state of the internal combustion engine, the learning value is updated again when the degree of deviation further increases. The learning value can be updated repeatedly as it increases.

A control apparatus for an internal combustion engine according to an embodiment embodying the present invention will be described below.
FIG. 1 shows a schematic configuration of an internal combustion engine to which the control device according to the present embodiment is applied.

  As shown in FIG. 1, the intake passage 11 of the internal combustion engine 10 is provided with a throttle valve 12 for changing the passage sectional area. A throttle motor 13 is connected to the throttle valve 12. Then, the opening degree of the throttle valve 12 (throttle opening degree TA) is adjusted through the drive control (throttle control) of the throttle motor 13, thereby adjusting the amount of air taken into the combustion chamber 14 through the intake passage 11. The The intake passage 11 is provided with a fuel injection valve 15. Fuel is injected into the intake passage 11 through drive control (fuel injection control) of the fuel injection valve 15.

  The internal combustion engine 10 is provided with a spark plug 16 for igniting an air-fuel mixture composed of intake air and injected fuel inside the combustion chamber 14. An igniter 17 is connected to the spark plug 16. The spark plug 16 operates when a high voltage output from the igniter 17 is applied. Through the operation control (ignition timing control) of the igniter 17, the air-fuel mixture burns at an appropriate timing, the piston 18 reciprocates, and the crankshaft 19 as the output shaft of the internal combustion engine 10 rotates. The air-fuel mixture after combustion is sent out from the combustion chamber 14 to the exhaust passage 20 as exhaust.

  In the internal combustion engine 10, the intake passage 11 and the combustion chamber 14 are communicated and blocked by the opening / closing operation of the intake valve 21. The intake valve 21 opens and closes with the rotation of the intake camshaft 22 to which the rotation of the crankshaft 19 is transmitted. On the other hand, the combustion chamber 14 of the internal combustion engine 10 and the exhaust passage 20 are communicated and blocked by the opening / closing operation of the exhaust valve 23. The exhaust valve 23 opens and closes with the rotation of the exhaust camshaft 24 to which the rotation of the crankshaft 19 is transmitted.

FIG. 2 shows a schematic configuration of a vehicle on which the internal combustion engine 10 is mounted.
As shown in FIG. 2, in the vehicle 30, the crankshaft 19 of the internal combustion engine 10 as a drive source thereof is a flywheel 31 fixed to the end of the crankshaft 19, and the driver operates the clutch pedal 32. Accordingly, the flywheel 31 and the transmission 33 are connected to the transmission 33 via a clutch 34 that connects and disconnects the flywheel 31 and the transmission 33. A propeller shaft 35 that is an output shaft of the transmission 33 is connected via a differential gear 36 to a drive shaft 38 on which wheels 37 are mounted.

  The transmission 33 can be switched between a neutral state in which the driving force of the crankshaft 19 is not transmitted to the wheel 37 side and a transmission state in which the driving force of the crankshaft 19 is transmitted to the wheel 37 side by operating the shift lever 39 by the driver. This is a multi-stage manual transmission. Specifically, a neutral (N) position where the driving force of the crankshaft 19 is not transmitted to the wheel 37 side, and a forward shift position (1st to 5th) transmitted to the wheel 37 side after the rotation of the crankshaft 19 is shifted. Speed), the shift position of the reverse shift position transmitted to the wheel 37 side after the rotation of the crankshaft 19 is reversed is selected by the operation of the shift lever 39 by the driver.

  When the rotational force is output to the crankshaft 19 by the internal combustion engine 10 to drive the vehicle 30 and the transmission 33 is in the transmission state (forward shift position or reverse shift position), the flywheel 31 and the transmission 33 Are coupled by a clutch 34. Thus, the rotational force of the crankshaft 19 is finally transmitted to the wheel 37 via the clutch 34 through the transmission 33, the propeller shaft 35, the differential gear 36, and the drive shaft 38 in this order.

  The vehicle 30 is provided with a starter motor 40 that generates torque. The starter motor 40 is driven when the internal combustion engine 10 is started, and the rotational force is transmitted to the crankshaft 19. Thereby, starting of the internal combustion engine 10 is assisted.

  The vehicle 30 includes various sensors for detecting the operation state and the operation state of the internal combustion engine 10. Such sensors include, for example, a crank sensor 51 for detecting the rotational speed of the crankshaft 19 (engine rotational speed NE) of the internal combustion engine 10 (FIG. 1), and the intake passage 11 upstream of the throttle valve 12 in the intake flow direction. An air flow meter 52 is provided for detecting the amount of air passing through the intake passage 11 (passage intake amount GA). Further, an accelerator sensor 53 for detecting the depression amount AC of the accelerator pedal 41, a throttle sensor 54 for detecting the throttle opening degree TA, and a temperature sensor 55 for detecting the temperature of the engine cooling water (cooling water temperature THW). Is provided. In addition, a clutch sensor 58 for detecting whether or not the clutch pedal 32 is depressed, a brake sensor 59 for detecting whether or not the brake pedal 42 is depressed, and a speed for detecting the traveling speed of the vehicle 30 (vehicle speed SPD). A sensor 60 and the like are also provided.

  In addition, the vehicle 30 is provided with an electronic control unit 50 configured with, for example, a microcomputer. The electronic control device 50 takes in the detection signals of the sensors and performs various calculations, and executes various controls such as throttle control, fuel injection control, and ignition timing control based on the calculation results.

  In the present embodiment, the amount of air taken into the combustion chamber 14 (FIG. 1) of the internal combustion engine 10 (in-cylinder intake amount) is adjusted as follows. That is, first, a control target value (required in-cylinder intake air amount Tga) for the in-cylinder intake air amount is calculated based on the depression amount AC of the accelerator pedal 41, the engine speed NE, and an ISC learning value GK described later. . Next, as a control target value (target throttle opening degree Tta) for the throttle opening degree TA, a value is calculated so that the required in-cylinder intake air amount Tga and the actual in-cylinder intake air amount coincide with each other.

  Then, the drive of the throttle motor 13 is controlled so that the target throttle opening degree Tta and the actual throttle opening degree TA coincide with each other. Through such throttle control, the amount of air taken into the combustion chamber 14 of the internal combustion engine 10 is adjusted to an amount suitable for the operating state.

  In the present embodiment, the required in-cylinder intake air amount Tga is calculated by adding the basic intake air amount corresponding to the ISC learning value GK to the additional intake air amount corresponding to the depression amount AC of the accelerator pedal 41. The basic intake air amount is a value corresponding to the in-cylinder intake air amount that enables stable operation of the internal combustion engine 10 when the accelerator pedal 41 is not depressed, and the added intake air amount is to be increased by depressing the accelerator pedal 41. This value corresponds to the intake air amount. In the present embodiment, the processing relating to the adjustment of the in-cylinder intake air amount functions as an adjusting means.

  The vehicle 30 (FIG. 2) automatically stops the internal combustion engine 10 when the vehicle 30 stops at an intersection or the like, and automatically starts the internal combustion engine 10 at any timing during the automatic stop so that the vehicle 30 can start. It has an automatic stop / start function. With this automatic stop / start function, the fuel consumption and emission of the internal combustion engine 10 can be reduced.

  Hereinafter, a process for automatically stopping the internal combustion engine 10 (automatic stop process) and a process for automatically starting the internal combustion engine 10 (restart process) will be described with reference to FIGS. 3 and 4. In the present embodiment, these automatic stop processing and restart processing function as automatic stop starting means.

  FIG. 3 is a flowchart showing the procedure of the automatic stop process, and FIG. 4 is a flowchart showing the procedure of the restart process. The series of processes shown in these flowcharts is executed by the electronic control unit 50 as an interrupt process for each predetermined period.

Here, first, the processing procedure of the automatic stop process will be described with reference to FIG.
As shown in FIG. 3, in this process, first, the operating state of the vehicle 30 and the internal combustion engine 10 is read through the detection signals of the various sensors (step S101), and the automatic stop condition is established from the operating state. Is determined (step S102). Specifically, for example, it is determined that the automatic stop condition is satisfied when all of the following conditions (a) to (g) are satisfied.
(A) The vehicle 30 is stopped.
(B) The internal combustion engine 10 has been warmed up (the cooling water temperature THW is higher than the water temperature lower limit).
(C) The accelerator pedal 41 is not depressed.
(D) The brake pedal 42 is depressed.
(E) The clutch pedal 32 is depressed.
(F) The operating position of the shift lever 39 is the (N) position.
(G) There is no history of execution of the automatic stop of the internal combustion engine 10 after all of the above conditions (a) to (g) are satisfied.

  When any one of the above conditions (A) to (G) is not satisfied (step S102: NO), the automatic stop condition is not satisfied, and the condition for executing the automatic stop of the internal combustion engine 10 is satisfied. If this is not the case, the present process is temporarily terminated.

  Thereafter, when it is determined that the automatic stop condition is satisfied because the vehicle 30 stops at the intersection (step S102: YES), for example, the fuel supply to the internal combustion engine 10 is stopped and the internal combustion engine is stopped. The operation of the engine 10 is stopped (S103). Thereafter, this process is temporarily terminated.

  As described above, in the present embodiment, it is determined that the automatic stop condition including the condition that the engine operation state is the specific operation region is satisfied when all of the conditions (b) to (g) are satisfied, Based on this determination, the operation of the internal combustion engine 10 is automatically stopped. Note that, as is clear from the conditions (A) to (G), the specific operation region includes the idle operation region of the internal combustion engine 10.

Next, with reference to FIG. 4, the processing procedure of the restart process will be described.
As shown in FIG. 4, in this process, first, the operation state of the vehicle 30 and the internal combustion engine 10 is read through the detection signals of the various sensors (step S201), and the restart condition is established from the operation state. Is determined (step S202). Specifically, under the condition that the internal combustion engine 10 is in a stopped state through the automatic stop process described above, if any one of the above conditions (A) to (F) is not satisfied, the restart condition Is determined to have been established.

  When the internal combustion engine 10 is not automatically stopped or when the internal combustion engine 10 is automatically stopped, if all of the above conditions (A) to (F) are satisfied (step) (S202: NO), the restart condition is not satisfied, and it is determined that the restart condition of the internal combustion engine 10 is not satisfied.

  Thereafter, when any one of the above conditions (A) to (F) is not satisfied in the automatic stop state of the internal combustion engine 10 (step S202: YES), the internal combustion engine 10 is restarted assuming that the restart condition is satisfied. Processing is executed (step S203). Specifically, the starter motor 40 is driven to perform cranking of the internal combustion engine 10, and well-known fuel injection control and ignition timing control are performed to restart the internal combustion engine 10. Thereafter, this process is temporarily terminated.

  In the present embodiment, as the ISC learning value GK described above, a learning value is calculated for the intake air amount (specifically, the in-cylinder intake amount) that can stably operate the internal combustion engine 10 during idle operation.

  Usually, learning of the ISC learning value GK is executed based on the intake air amount when the internal combustion engine 10 is idling. In the present embodiment, the automatic stop of the internal combustion engine 10 by the automatic stop start function is executed on condition that the operation region of the internal combustion engine 10 is a specific operation region including the idle operation region. Therefore, if the ISC learning value GK is learned on the basis of the intake air amount during the idling operation of the internal combustion engine 10, the opportunity for detecting the intake air amount, and consequently the learning opportunity for the ISC learned value GK, is extremely reduced. There is a possibility that the ISC learning value GK may become a value far from the value in accordance with the actual situation.

  Therefore, in the present embodiment, learning of the ISC learning value GK is performed based on the intake air amount when the engine operation region is an operation region other than the specific operation region. Thus, the ISC learning value GK that enables stable operation of the internal combustion engine 10 during idle operation is learned based on the intake air amount in the operation region other than the specific operation region, in other words, in the operation region other than the idle operation region. Will come to be. Therefore, it is not necessary to prohibit the automatic stop of the internal combustion engine 10 in order to learn the ISC learning value GK, the execution frequency of the automatic stop of the internal combustion engine 10 is maintained high, and the fuel consumption is preferable by the automatic stop start function. To be reduced.

  Here, the intake air amount during the idling operation of the internal combustion engine 10 and the intake air amount in the operation region other than the specific operation region have a high correlation. Therefore, the relationship between these intake air amounts is obtained in advance based on the results of experiments and simulations, etc., so that the intake air amount in the operation region other than the specific operation region can be It is possible to obtain the intake air amount with high accuracy.

  For this reason, in the present embodiment, although the ISC learning value GK is learned based on the intake air amount in a region other than the idle operation region of the internal combustion engine 10, the actual value of the intake air amount (in this embodiment, Based on the passage intake air amount GA), a correction amount of the intake air amount suitable for stable operation of the internal combustion engine 10 during idle operation can be obtained, and the ISC learning value GK is learned based on the correction amount. can do. Therefore, the engine operating state can be suitably stabilized by the learning function based on the ISC learning value GK.

In this embodiment, the ISC learning value GK includes a basic value GKb and a correction amount GKk, and a value obtained by adding the basic value GKb and the correction amount GKk is obtained as an ISC learning value GK (= GKb + GKk). The basic value GKb is a value for compensating for the difference between the in-cylinder intake amount and the reference amount due to individual differences in the intake system components (for example, the intake passage 11 and the throttle valve 12) of the internal combustion engine 10, It is obtained through operation of an external device connected to the vehicle 30 before shipment from the factory, and is stored in advance in the electronic control unit 50 (specifically, its nonvolatile memory 50a). The correction amount GKk is a value for compensating for the difference between the in-cylinder intake amount and the reference amount caused by the change in intake system components of the internal combustion engine 10 with time, and is learned through the following learning process. In the present embodiment, this learning process functions as learning means.

Hereinafter, the execution procedure of the learning process will be described.
FIG. 5 is a flowchart showing a specific processing procedure of the learning process, and FIG. 6 is a timing chart showing an example of an execution mode of the learning process. Note that the series of processing shown in the flowchart of FIG. 5 is executed by the electronic control unit 50 as processing at predetermined intervals.

As shown in FIG. 5, in this process, it is first determined whether or not an execution condition is satisfied (step S301). Here, it is determined that the execution condition is satisfied when all of the following conditions are satisfied.
The internal combustion engine 10 is not automatically stopped through the automatic stop process.
The throttle opening TA is smaller than the predetermined opening (specifically, the opening corresponding to the opening “idle opening” when the throttle opening TA is in the idle operation state).

  If the execution condition is not satisfied (step S301: NO), the following processing (steps S302 to S305, S307 to S311) is performed unless the execution condition is not satisfied (step S306: NO). ) Is temporarily terminated without executing.

  In the example shown in FIG. 6, the vehicle 30 is traveling in a state where the throttle opening degree TA is large and the passage intake air amount GA is large before the time t1, and the following processing is performed because the execution condition is not satisfied. Not executed. When the depression of the accelerator pedal 41 is released while the vehicle 30 is traveling, the throttle opening degree TA becomes a very small opening degree (idle opening degree), whereby the execution condition is satisfied (after time t1). Then, execution of the following processing is started.

  That is, when the execution of the learning process is repeated and the above execution condition is satisfied (step S301 in FIG. 5: YES), first, the reference value for the passage intake air amount GA is determined from the map based on the throttle opening degree TA and the engine speed NE. GATA is obtained (step S302). As the reference value GATA, a value corresponding to the passage intake air amount GA when the internal combustion engine 10 having the reference characteristics is assumed to have not changed with time is obtained. In the map, the relationship between the reference value GATA and the engine operating state determined by the throttle opening degree TA and the engine speed NE is obtained from experimental results and set. This map is stored in advance in the electronic control unit 50 (specifically, its ROM). Thus, in the present embodiment, since the reference value GATA is calculated from the map based on the operating state of the internal combustion engine 10, the reference value GATA can be accurately calculated over a wide operating region.

  Next, a difference ΔGA (= GATA−GA) between the reference value GATA and the actual passage intake air amount GA is calculated (step S303), and the average value of the difference ΔGA in a period in which the execution condition is continuously established. ΔGAave is calculated (step S304).

  Further, an average value NEave is calculated for the engine rotational speed NE at the timing when the difference ΔGA is calculated during the period in which the execution condition is established (step S305). After such processing, this processing is temporarily terminated.

  Here, when the internal combustion engine 10 is in the idling operation region and when it is in the other operation region, the throttle opening TA is set to a different opening, and the intake air amount is adjusted to a different amount.

  When the ISC learning value GK is learned based on the intake air amount when the region is other than the idling operation region as in the present embodiment, the engine operation region is applied when the ISC learning value GK is actually applied (application). ) And when detecting the actual value of the intake air amount (passage intake air amount GA) for learning the ISC learning value GK (at the time of detection). For this reason, the intake air amount differs between the application time and the detection time due to such a difference in the engine operation region, and the ISC learning value GK is accordingly based on the intake air amount in the idle operation region. Compared with the case of learning, it can be said that the learning accuracy of the ISC learning value GK is likely to be lowered.

  In the present embodiment, when the execution condition is satisfied, it is determined that the throttle opening TA is small, in other words, that the difference in the intake air amount due to the difference in the engine operation region is the engine operation region. The difference ΔGA is obtained based on the passage intake air amount GA detected when the engine operating region is set. This makes it possible to calculate a value that is unlikely to cause a decrease in the learning accuracy of the ISC learning value GK as the difference ΔGA.

The processes in steps S302 to S305 are repeatedly executed while the execution condition is established (step S301: YES).
Thereafter, when the execution condition is not satisfied (step S301: NO and step S306: YES), the converted value GAcn is calculated from the map based on the average value ΔGAave of the difference ΔGA and the average value NEave of the engine speed NE ( Step S307).

  Here, a value obtained by converting the average value ΔGAave so as to be a value corresponding to the average value ΔGAave of the difference ΔGA when the engine rotational speed NE is the reference rotational speed NEb is calculated as the converted value GAcn. In the map, there is a relationship in which the converted value GAcn is calculated in this way (specifically, a relationship between the average value ΔGAave of the difference ΔGA, the average value NEave of the engine rotational speed NE, and the converted value GAcn). The map is obtained and set based on the results of experiments and simulations, and the map is stored in advance in the electronic control unit 50 (specifically, its ROM). Note that, as the reference rotation speed NEb, a standard engine rotation speed NE (for example, 650 rotations / minute) during the idling operation of the internal combustion engine 10 having a reference characteristic is set.

  Next, it is determined whether or not the converted value GAcn satisfies the relational expression “upper limit value MAX> converted value GAcn> lower limit value MIN” (step S308). Here, when the above relational expression is satisfied, the difference between the current correction amount GKk and the converted value GAcn is less than a predetermined amount (in this embodiment, an amount corresponding to 1% of the correction amount GKk). To be judged.

  When the above relational expression is not satisfied (step S308: NO), that is, when “upper limit MAX ≦ converted value GAcn” or “converted value GAcn ≦ lower limit MIN”, the difference ΔGA is large. Assuming that the change in the in-cylinder intake amount due to the time-dependent change of the intake system components of the internal combustion engine 10 is progressing, the converted value GAcn at this time is stored as the correction amount GKk (step S309).

  Thereafter, a value obtained by adding the update amount of the correction amount GKk in the process of step S309 (specifically, “correction amount GKk after update” − “correction amount GKk before update”) to the upper limit MAX and the lower limit MIN, respectively. The new upper limit value MAX and lower limit value MIN are calculated (step S310). Then, after both the average value ΔGAave of the difference ΔGA and the average value NEave of the engine rotational speed NE are reset to “0” (step S311), this process is temporarily ended.

  The example illustrated in FIG. 6 illustrates an execution mode of the learning process when the converted value GAcn and the upper limit value MAX are equal. In the example shown in FIG. 6, when the execution condition is not satisfied (time t2), the converted value GAcn obtained at this time is stored as the correction amount GKk, and the upper limit value MAX and the lower limit value MIN are updated amounts of the correction amount GKk. It is changed by (amount indicated by “A” in the figure).

  On the other hand, if the above relational expression is satisfied (step S308 in FIG. 5: YES), the difference ΔGA is small, and it is assumed that the change in the in-cylinder intake amount due to the change with time of the intake system components of the internal combustion engine 10 has not progressed much. The process of updating the correction amount GKk (step S309) and the process of changing the upper limit value MAX and the lower limit value MIN (step S310) are not executed (jumped). Then, after the average value ΔGAave of the difference ΔGA and the average value NEave of the engine rotational speed NE are reset to “0” (step S311), this process is temporarily ended.

  As described above, in the present embodiment, on the condition that the degree of deviation between the passage intake air amount GA and the reference value GATA is greater than or equal to a predetermined value, specifically, the converted value GAcn is greater than or equal to the upper limit MAX or the lower limit. The update of the correction amount GKk is permitted on condition that the value is MIN or less. Therefore, the correction amount GKk is updated only when the change in the in-cylinder intake amount due to the time-dependent change of the intake system components of the internal combustion engine 10 advances and the possibility that the operating state of the internal combustion engine 10 becomes unstable becomes high. Accordingly, the instability of the operating state of the internal combustion engine 10 can be accurately suppressed while the update frequency of the correction amount GKk is suppressed.

  In the present embodiment, when the correction amount GKk is updated, the upper limit MAX and the lower limit MIN are changed by an amount equal to the update amount of the correction amount GKk in accordance with the update. Therefore, after it is once determined that the converted value GAcn has changed by more than the allowable amount through the process based on the upper limit MAX and the lower limit MIN, the conversion is performed through the process based on the upper limit MAX and the lower limit MIN changed according to the determination. It can be determined that the value GAcn has further changed. Accordingly, the change in the conversion value GAcn is updated such that the correction amount GKk is updated once again after the correction amount GKk is once updated to suppress the instability of the operating state of the internal combustion engine 10. Accordingly, the correction amount GKk can be repeatedly updated.

  Then, immediately after the execution condition is not satisfied, the process for updating the correction amount GKk is executed (step S301: NO and step S306: NO), and the processes of steps S307 to S311 are not executed. (Jumped), the process is temporarily terminated.

  In the learning process of the present embodiment, the correction amount GKk is updated based on the difference ΔGA between the passage intake air amount GA and the reference value GATA in the region other than the specific operation region. Therefore, the update of the correction amount GKk, and hence the learning of the ISC learning value GK, can be executed based on the passage intake air amount GA in the operation region other than the specific operation region, in other words, the operation region other than the idle operation region. . As a result, it is not necessary to prohibit the automatic stop of the internal combustion engine 10 in order to learn the ISC learning value GK, so that it is possible to maintain a high frequency of execution of the automatic stop of the internal combustion engine 10, and an automatic stop start function As a result, the fuel consumption can be suitably reduced.

  Moreover, although the ISC learning value GK is learned based on the intake air amount in a region other than the idle operation region of the internal combustion engine 10, it is based on the difference ΔGA between the passage intake air amount GA and a predetermined reference value GATA. A correction amount that can suppress the difference ΔGA, in other words, a correction amount suitable for stable operation of the internal combustion engine 10 during idle operation is obtained, and based on this, an ISC learning value GK (specifically, a correction amount) is obtained. GKk) can be learned. Therefore, the engine operating state can be suitably stabilized by the learning function based on the ISC learning value GK.

As described above, according to the present embodiment, the effects described below can be obtained.
(1) The fuel consumption can be suitably reduced by the automatic stop / start function, and the engine operating state can be suitably stabilized by the learning function based on the ISC learning value GK.

  (2) Since the reference value GATA is calculated based on the throttle opening degree TA and the engine rotational speed NE based on the map stored in advance, the reference value GATA can be calculated with high accuracy over a wide operation region. As a result, the ISC learning value GK can be learned.

  (3) When the throttle opening degree TA is small, in other words, the difference ΔGA based on the passage intake air amount GA detected when the difference in the intake air amount due to the difference in the engine operation region is a small engine operation region. I asked for it. Therefore, it is possible to calculate a value that is unlikely to cause a decrease in the learning accuracy of the ISC learning value GK as the difference ΔGA, and to learn the ISC learning value GK with high accuracy.

  (4) The update of the correction amount GKk is permitted on condition that the converted value GAcn is not less than the upper limit value MAX or not more than the lower limit value MIN. Therefore, the correction amount GKk is updated only when the change in the in-cylinder intake air amount due to the time-dependent change of the intake system parts of the internal combustion engine 10 advances and the operation state of the internal combustion engine 10 is likely to become unstable. Instability of the operating state of the internal combustion engine 10 can be accurately suppressed while suppressing the update frequency of the correction amount GKk.

  (5) When the correction amount GKk is updated, the upper limit MAX and the lower limit MIN are changed by an amount equal to the update amount of the correction amount GKk in accordance with the update. Therefore, the change in the converted value GAcn is updated such that the correction value GKk is updated again after the correction value Gcn is further changed after the correction value GKk is once updated to suppress the instability of the operating state of the internal combustion engine 10. Accordingly, the correction amount GKk can be repeatedly updated.

The embodiment described above may be modified as follows.
As a calculation parameter for the reference value GATA, the target throttle opening degree Tta may be used instead of using the throttle opening degree TA. Also, parameters for calculating the target throttle opening degree Tta (specifically, the depression amount AC of the accelerator pedal 41, the engine speed NE, the ISC learning value GK, and the required in-cylinder intake amount Tga) are used as the calculation parameter for the reference value GATA. Can also be used. In short, it is only necessary that the reference value GATA can be accurately obtained based on the operating state of the internal combustion engine 10.

  The period for calculating the average value ΔGAave of the difference ΔGA and the average value NEave of the engine rotational speed NE is not limited to the period in which the execution condition is continued, and can be arbitrarily changed. In this case, the correction amount GKk may be updated based on the average values ΔGAave and NEave when the period ends.

  Instead of calculating the average value ΔGAave of the difference ΔGA and the average value NEave of the engine speed NE, for example, “{“ previously calculated gradual change value ”× (N−1) +“ value detected this time ” Each time the difference ΔGA is calculated, a gradual change value of the difference ΔGA or the engine rotational speed NE may be calculated through a calculation formula such as “} / N”. In this case, the correction amount GKk may be updated at an arbitrary timing based on the gradual change value of the difference ΔGA and the gradual change value of the engine rotational speed NE.

  Based on the difference ΔGA between the passage intake air amount GA and the reference value GATA and the engine rotation speed NE when the passage intake air amount GA is detected without calculating the average value ΔGAave of the difference ΔGA and the average value NEave of the engine rotation speed NE. Thus, the correction amount GKk may be updated.

  -Every time the difference ΔGA is calculated, the difference ΔGA is converted so as to be a value corresponding to the difference ΔGA when the engine rotational speed NE is the reference rotational speed NEb, and the average value of the converted values is used as a converted value. You may make it ask.

  If the decrease in the learning accuracy of the ISC learning value GK due to the difference in the intake air amount due to the difference in the engine operating region at the time of application and detection is appropriately suppressed, the “throttle opening TA is The condition that it is smaller than the predetermined opening degree may be omitted.

As an execution condition, a condition that “the amount of gas flowing into the combustion chamber 14 without passing through the throttle valve 12 is small” may be newly added and set. Here, even if the throttle opening degree TA is the same, the gas that flows into the combustion chamber 14 without passing through the throttle valve 12 (for example, the gas after combustion returned to the intake passage 11 from the exhaust passage 20 or the combustion chamber 14 [ When the amount of EGR gas]) is different, the amount of intake air of the internal combustion engine 10 is also different. In general, since it is difficult to precisely measure the amount of such gas flowing into the combustion chamber 14, the actual value of the intake air amount detected when the gas flows into the combustion chamber 14 is sometimes changed. An error is likely to occur between the value corresponding to the engine operating state. In this regard, according to the above configuration, the difference ΔGA is calculated based on the actual value detected when the amount of the gas flowing into the combustion chamber 14 is small, in other words, when the error due to the inflow of the gas is small. The difference ΔGA can be obtained with high accuracy. As such conditions, for example, the following “condition a” to “condition c” can be set.
“Condition A” In an internal combustion engine provided with a changing mechanism for changing the opening timing of the intake valve 21 and a valve characteristic changing mechanism for changing the closing timing of the exhaust valve 23, both the intake valve 21 and the exhaust valve 23 are opened. The valved period (valve overlap period) is shorter than the predetermined period.
“Condition B” In an internal combustion engine having an external EGR mechanism that includes an EGR passage that communicates with the exhaust passage 20 and the intake passage 11 and an EGR valve that is provided in the EGR passage and changes the passage sectional area thereof, the opening of the EGR valve The degree is not more than a predetermined opening (for example, 0 [= valve closing]).
The vehicle is equipped with an internal combustion engine equipped with a “condition C” changing mechanism and an external EGR mechanism, and the vehicle is traveling at a reduced speed (specifically, the speed of decrease in the vehicle speed SPD is equal to or higher than a predetermined speed) thing). Note that when the depression of the accelerator pedal 41 is released while the vehicle is running, the throttle opening TA becomes a very small opening (the idle opening), the in-cylinder intake amount decreases, and the vehicle speed SPD decreases. At this time, normally, in the internal combustion engine provided with the valve characteristic changing mechanism, the operation of the valve characteristic changing mechanism is controlled so that the valve overlap period is shortened. In the internal combustion engine equipped with the external EGR mechanism, the EGR valve is controlled. Is adjusted to a small opening, and the amount of EGR becomes very small. Therefore, by adopting “Condition C”, it can be determined that the amount of EGR is small, that is, the amount of gas flowing into the combustion chamber 14 without passing through the throttle valve 12 is small.

  Instead of calculating the difference ΔGA between the passage intake air amount GA and the reference value GATA, a ratio Rga between the passage intake air amount GA and the reference value GATA may be calculated. In short, it is only necessary to obtain values corresponding to the degree of deviation between the passage intake air amount GA and the reference value GATA, such as the difference ΔGA and the ratio Rga. Even with such a configuration, it is possible to calculate the conversion value based on the degree of divergence, update the correction amount based on the conversion value, and learn the ISC learning value GK.

  A value obtained by multiplying the basic value and the correction amount may be obtained as the ISC learning value. Also in this case, the correction amount may be updated based on the degree of deviation between the passage intake air amount GA and the reference value GATA in a manner similar to the above embodiment.

  The learning method of the basic value GKb can be arbitrarily changed. Specifically, a known learning method for learning a learning value for the intake air amount during execution of idle speed control (ISC) control, a method for updating the correction amount described above, or the like can be employed.

  The timing for learning the basic value GKb is not limited to before the factory shipment of the vehicle 30, but may be after the factory shipment of the vehicle 30. In this case, it is desirable to prohibit the update of the correction amount GKk until the learning of the basic value GKb is completed.

  The basic value GKb may be omitted and the correction amount GKk may be used as the ISC learning value GK. Also with this configuration, through the learning of the ISC learning value GK, it is possible to compensate for the difference between the in-cylinder intake amount and its reference amount due to individual differences in intake system components of the internal combustion engine 10 and changes over time.

The automatic stop condition can be appropriately changed as long as it includes a condition that the engine operation region is a specific operation region including the idle operation region.
The present invention can be applied to a vehicle provided with an automatic transmission.

The present invention can also be applied to a control device that performs ISC control during idling when the internal combustion engine is not automatically stopped.
The present invention can be applied not only to a device that learns a learned value for the intake air amount as an ISC learned value, but also to a device that learns a learned value for the fuel injection amount as an ISC learned value. In this case, the ISC learning value may be learned as follows. That is, first, a reference value for the fuel injection amount is obtained based on the opening time of the fuel injection valve in the fuel injection control executed in the operation region other than the specific operation region. In accordance with this, the actual value of the fuel injection amount is calculated based on the air-fuel ratio of the air-fuel mixture detected through the air-fuel ratio sensor provided in the exhaust passage and the passage intake air amount detected through the intake air amount sensor. Then, learning of the ISC learning value is executed based on the degree of deviation between the actual value of the fuel injection amount and the reference value.

1 is a schematic configuration diagram of an internal combustion engine to which a control device according to an embodiment embodying the present invention is applied. The schematic block diagram of the vehicle by which an internal combustion engine is mounted. The flowchart which shows the specific process sequence of an automatic stop process. The flowchart which shows the specific process sequence of a restart process. The flowchart which shows the specific process sequence of a learning process. The timing chart which shows an example of the process aspect of a learning process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Intake passage, 12 ... Throttle valve, 13 ... Throttle motor, 14 ... Combustion chamber, 15 ... Fuel injection valve, 16 ... Spark plug, 17 ... Igniter, 18 ... Piston, 19 ... Crankshaft, 20 DESCRIPTION OF SYMBOLS ... Exhaust passage, 21 ... Intake valve, 22 ... Intake camshaft, 23 ... Exhaust valve, 24 ... Exhaust camshaft, 30 ... Vehicle, 31 ... Flywheel, 32 ... Clutch pedal, 33 ... Transmission, 34 ... Clutch, 35 ... propeller shaft, 36 ... differential gear, 37 ... wheel, 38 ... drive shaft, 39 ... shift lever, 40 ... starter motor, 41 ... accelerator pedal, 42 ... brake pedal, 50 ... electronic control unit, 50a ... memory, 51 ... Crank sensor, 52... Air flow meter (detection means), 53. , 54 ... throttle sensor, 55 ... temperature sensor, 58 ... clutch sensor, 59 ... brake sensor, 60 ... speed sensor.

Claims (7)

A learning means for learning a learning value for an engine control amount capable of stably operating the internal combustion engine during idling operation, an adjusting means for adjusting the engine control amount based on the learning value, and an engine operation region being an idle operation region The internal combustion engine is temporarily automatically stopped when a predetermined stop condition including a condition that it is in a specific operation region including the engine is satisfied, and the internal combustion engine is restarted when a predetermined restart condition is satisfied In an internal combustion engine control device comprising automatic stop and start means,
Detecting means for detecting an actual value of the engine control amount;
The control device for an internal combustion engine, wherein the learning means executes learning of the learning value based on a deviation degree between the actual value and a predetermined reference value in a region other than the specific operation region. The control apparatus for an internal combustion engine according to claim 1,
The control device stores in advance the relationship between the operating state of the internal combustion engine and the reference value,
The control device for an internal combustion engine, wherein the learning means obtains the reference value from the relationship based on an operating state of the internal combustion engine. The control apparatus for an internal combustion engine according to claim 1 or 2,
The control apparatus for an internal combustion engine, wherein the engine control amount is an intake air amount. The control apparatus for an internal combustion engine according to claim 3,
The internal combustion engine is provided with a throttle valve that changes the cross-sectional area of the intake passage,
The detection means is an air flow meter provided upstream of the throttle valve in the intake passage in the intake flow direction,
The operating state of the internal combustion engine is an opening degree of the throttle valve and an engine rotational speed. The control apparatus for an internal combustion engine according to claim 4,
The learning means obtains the degree of deviation based on the actual value detected when the execution condition that the opening degree of the throttle valve is smaller than a predetermined opening degree is satisfied and the reference value. A control device for an internal combustion engine. In the control device for an internal combustion engine according to any one of claims 1 to 5,
The control device for an internal combustion engine, wherein the learning means permits the learning value to be updated on condition that the degree of deviation is larger than a predetermined value. The control apparatus for an internal combustion engine according to claim 6,
The learning means changes the predetermined value by an amount corresponding to the update amount in accordance with the update of the learning value.

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