JP2005226554A - Control device for internal combustion engine and control method for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more appropriately update learned values in an unlearned region and secure good startability of an internal combustion engine. <P>SOLUTION: Out of the learned values in the unlearned region, learned values in a region in which intake air amount is smaller than that in a learn-completed region and which is not positioned in a lean side are updated after guard processing in a guard range R is performed (S190, S200). Out of the learned values in the unlearned region, learned values in a region in which intake air amount is smaller than that in the learn-completed region and which is positioned in the lean side are updated by using the learned values without performing guard processing in the guard range R (S180, S200). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an internal combustion engine control device and an internal combustion engine control method.

Conventionally, as a control device for this type of internal combustion engine, an apparatus that updates a learning value based on position information with respect to a learning area that has not been learned in learning of an air-fuel ratio has been proposed (for example, Patent Document 1). In this device, a reflection ratio is set by position information about a learned learning area with respect to an unlearned learning area, and the learning value of the unlearned learning area is updated based on the set reflection ratio and the learned learning value. Thereby, the learning accuracy of the entire learning region is made uniform.
JP-A-8-284716

  However, in the control device for an internal combustion engine described above, the learning value of the unlearned learning region may not be updated properly. In the unlearned learning region where the intake air amount is large, even if the learned value is slightly deviated from the appropriate value, the internal combustion engine is not significantly affected because the intake air amount is large due to the large intake air amount. In the region where the intake air amount is small, even if the learning value is slightly deviated from the appropriate value, the intake air amount is small, which greatly affects the operation of the internal combustion engine. In particular, when starting the internal combustion engine, it may not be possible to obtain a good startability, so an abnormality determination may occur. In a hybrid vehicle that automatically stops or starts an internal combustion engine, a slight decrease in startability may be processed as an abnormality detection.

  An object of the control device and the control method for an internal combustion engine of the present invention is to update the learning value in the unlearned region more appropriately. Another object of the control device and control method for an internal combustion engine of the present invention is to ensure good startability of the internal combustion engine.

  The internal combustion engine control apparatus and internal combustion engine control method according to the present invention employ the following means in order to achieve at least a part of the above-described object.

The control device for an internal combustion engine of the present invention comprises:
A control device for an internal combustion engine,
Learning execution means for performing learning regarding the air-fuel ratio in fuel injection control for the internal combustion engine with a plurality of intake air amount regions as a plurality of learning regions;
Of the plurality of learning regions, the learning value of the learning completion region in which learning by the learning execution unit has been completed is the learning value, and learning by the learning execution unit is not completed in the plurality of learning regions. The learning value in the unlearned area and the learning value in the area where the intake air amount is larger than the learning completion area and the learning value on the rich side in the area where the intake air amount is smaller than the learning completion area are based on the learning value in the learning completion area The corrected result is used as the learning result, and the learning value is used as the learning result for the learning value on the lean side in the region where the intake air amount is smaller than the learning completion region among the learning values in the unlearned region among the plurality of learning regions. A learning result adjusting means for adjusting;
Fuel injection control means for executing fuel injection control for the internal combustion engine using the learning result adjusted by the learning result adjusting means;
It is a summary to provide.

  In the control apparatus for an internal combustion engine according to the present invention, the learning value for the learning value in the learning completion region is set as the learning result, and the learning value and the learning in the region that is the learning value in the unlearned region and has a larger intake air amount than the learning completion region. As for the learning value on the rich side in the region where the intake air amount is smaller than the completion region, the result of correction based on the learning value in the learning completion region is used as the learning result. For the learning value on the lean side in the region with a small amount, this learning value is adjusted as a learning result. And the fuel injection control with respect to an internal combustion engine is performed using the learning result adjusted in this way. Since the lean learning value in the region where the intake air amount is small greatly affects the startability of the internal combustion engine, it can be used as a learning result without any correction based on the learning value in the learning completion region. Can be ensured. Therefore, the learning value in the unlearned area can be updated more appropriately.

  In such a control apparatus for an internal combustion engine of the present invention, the correction based on the learning value in the learning completion region may be correction within a correction range based on the learning value in the learning completion region. In this case, the correction range may be a range that is set as a range of a predetermined deviation from the median value when the average value of the learned values in the learning completion region is the median value. Further, the learning result adjusting means is a learning value in an unlearned region among the plurality of learning regions, a learning value in a region where the intake air amount is larger than a learning completion region, and a region where the intake air amount is less than a learning completion region. For the learning value on the rich side, when the learning value is within the correction range, the learning value is adjusted as a learning result, and when the learning value is outside the correction range, the learning value of the values within the correction range is adjusted to the learning value. It may be a means for adjusting the closest value as a learning result.

The internal combustion engine control method of the present invention includes:
A control method for an internal combustion engine comprising:
(A) performing learning related to an air-fuel ratio in fuel injection control for the internal combustion engine with a plurality of intake air amount regions as a plurality of learning regions;
(B) The learning value of a learning completion region in which learning has been completed among the plurality of learning regions is used as a learning result, and a learning value of an unlearned region in which learning has not been completed among the plurality of learning regions. As a result of the correction based on the learning value in the learning completed region, the learning value in the region where the intake air amount is larger than the learning completion region and the learning value on the rich side in the region where the intake air amount is smaller than the learning completion region And the learning value for the lean side learning value in a region where the intake air amount is less than the learning completion region among the plurality of learning regions and the learning value in the unlearned region,
(C) The fuel injection control for the internal combustion engine is executed using the learning result.

  In the control method for an internal combustion engine of the present invention, the learning value for the learning value in the learning completion region is taken as the learning result, and the learning value and learning in the region that is the learning value in the unlearned region and has a larger intake air amount than the learning completion region. As for the learning value on the rich side in the region where the intake air amount is smaller than the completion region, the result of correction based on the learning value in the learning completion region is used as the learning result. For the lean learning value in the region where the amount is small, this learning value is used as a learning result, and fuel injection control for the internal combustion engine is executed using this learning result. Since the lean learning value in the region where the intake air amount is small greatly affects the startability of the internal combustion engine, it can be used as a learning result without any correction based on the learning value in the learning completion region. Can be ensured. Therefore, the learning value in the unlearned area can be updated more appropriately.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of a configuration of an engine system 20 in which a control device 60 for an internal combustion engine as an embodiment of the present invention is incorporated. The engine system 20 of the embodiment is mounted on an automobile as a power source, and includes an engine 22 and a control device 60 that drives and controls the engine 22.

  The engine 22 is configured as an internal combustion engine capable of outputting power using a hydrocarbon-based fuel such as gasoline or light oil. The engine 22 sucks air purified by an air cleaner 24 through a throttle valve 26 and a fuel injection valve 28. Is injected into the fuel chamber through the intake valve 30 and is explosively burned by an electric spark from the spark plug 32, and is pushed down by the energy. The reciprocating motion of the piston 34 is converted into the rotational motion of the crankshaft 36. Exhaust gas from the engine 22 is discharged to the outside air through a purification device (three-way catalyst) 38 that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx).

  The control device 60 is configured as a microcomputer centered on a CPU 62, and includes a ROM 64 for storing a processing program, a RAM 66 for temporarily storing data, an input / output port (not shown), and the like in addition to the CPU 62. The control device 60 includes a crank position from a crank position sensor 42 that detects the rotational position of the crankshaft 36, a cooling water temperature from a water temperature sensor 46 that detects the temperature of cooling water in the engine 22, and intake air that performs intake and exhaust to the combustion chamber. From the cam position from the cam position sensor 48 that detects the rotational position of the camshaft that opens and closes the valve 30 and the exhaust valve, from the throttle position from the throttle valve position sensor 50 that detects the position of the throttle valve 26, from the exhaust pipe purifier 38 The air-fuel ratio from the air-fuel ratio sensor 52 attached upstream, the oxygen signal from the oxygen sensor 54 attached downstream from the exhaust pipe purification device 38, the ignition signal from the ignition switch 80, the operating position of the shift lever 81 Detect shift The shift position SP from the transition sensor 82, the accelerator opening Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, and the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85 , Signals from various sensors that detect the state of the engine 22, such as the vehicle speed V from the vehicle speed sensor 88, are input via an input port (not shown). From the control device 60, a drive signal to the fuel injection valve 28, a drive signal to the throttle motor 40 for adjusting the position of the throttle valve 26, a control signal to the ignition coil 44 integrated with the igniter, the intake valve 30 Various control signals for driving the engine 22, such as a control signal to the variable valve timing mechanism 56 capable of changing the opening / closing timing, are output via an output port (not shown).

  The engine system 20 configured in this way has an opening degree of the throttle valve 26 so that a driving force according to the accelerator opening degree Acc as the depression amount of the accelerator pedal 83 and the vehicle speed V detected by the vehicle speed sensor 88 is output to the vehicle. The operation of the engine 22 is controlled by control, fuel injection control from the fuel injection valve 28, ignition control of the ignition plug 32, valve timing control of the variable valve timing mechanism 56, and the like.

  In the engine system 20, learning about the air-fuel ratio used for fuel injection control from the fuel injection valve 28 (hereinafter referred to as air-fuel ratio learning) is started at the timing when the engine 22 is started and warm-up is almost completed. . In the embodiment, the air-fuel ratio learning is performed in five learning areas: an idle operation area, a low intake air quantity area, a low / medium intake air quantity area, a medium / high intake air quantity area, and a high intake air quantity area. When the engine 22 is operating stably, the target air-fuel ratio is compared with the air-fuel ratio calculated from the actually detected value, the average value of the differences is used as the learning value, and the parameter in the calculation of the average value is predetermined. This is done by completing the learning when the number is reached. Since air-fuel ratio learning does not form the core of the present invention, further detailed description is omitted.

  Since such air-fuel ratio learning is performed in a plurality of learning regions, learning is not necessarily completed in all of the learning regions. Therefore, for updating the learning value, it is necessary to update the learning value in consideration of a region where learning is completed and a region where learning is not completed. In the embodiment, such learning value update processing is performed by the learning value update processing illustrated in FIG. This process is executed each time learning is completed after learning is completed in two or more learning regions.

  When the learning value update process is executed, the CPU 62 of the control device 60 first determines whether learning is completed in all learning regions (step S100). When learning is completed in all learning regions, the learning values in all learning regions are updated (step S110), and this process is terminated. When it is determined that learning has not been completed in all learning regions, it is determined whether there is a learning region in which learning has been completed (step S120), and when there is no learning region in which learning has been completed, This process is terminated. If there is a learning region in which learning has been completed, the learning value of the learning region in which learning has been completed is updated (step S130), and the average value C is used using the learning value of the learning region in which learning has been completed. (Step S140), and a guard range R having the average value C as the median value is set by adding or subtracting the value D to the calculated average value C (step S150).

  When the guard range R is set in this manner, learning values A of learning regions that have not been updated (unupdated regions) are sequentially extracted from learning values of learning regions that have not been learned (step S160), and the extracted learning The intake air amount region in the learning region of the value A is compared with the intake air amount region in the learning region of the learning value used when the guard range R is set (step S170). When the intake air amount region in the learning region of the extracted learning value A is higher (larger) than the intake air amount region in the learning region of the learning region used when the guard range R is set, the extracted learning value A is guarded. Guard processing is performed in the range (step S190), and the learning value A subjected to guard processing is updated (step S200). When the intake air amount region in the learning region of the extracted learning value A is lower (less) than the intake air amount region in the learning region of the learning region used when the guard range R is set, the learning value is on the lean side. (Step S180), when it is on the lean side, it is updated with the learning value A without performing guard processing (step S200), and when it is on the rich side, the extracted learning value A is guard-processed within the guard range. At the same time, the learning value A subjected to the guard process is updated (steps S190 and S200). The updating process for the learning value in the unlearned area is executed until there is no unupdated area (step S210). When all the learning values in the unlearned area are updated, the learning value updating process is terminated. As described above, when learning of the unlearned area is completed, the learning value is updated with the learning completed.

  FIG. 3 is an explanatory diagram for explaining how the learning value in the unlearned area is updated. In the figure, white circle learning values P1 to P3 are learning values in a learning region where learning is completed, and black circle learning values P4 to P7 are learning values in a learning region where learning is not completed. Further, in the figure, arrows indicate how learning values are changed by guard processing. In the learning value update processing of FIG. 2, the average value C of the learning values for setting the guard range is performed using the white circle learning values P1 to P3. Is set. The learning values P6 and P7 in the unlearned area are guarded by the guard range because the intake air amount is larger than the area in which learning has been completed. As a result, the learning value P6 outside the guard range is changed and updated within the guard range. Of the learning values P4 and P5 in the unlearned area, the learning value P5 is located on the rich side although the amount of intake air is smaller than the area where learning has been completed, and thus is updated by guard processing by the guard range. On the other hand, the learning value P4 has a smaller intake air amount than the area where learning has been completed and is positioned on the lean side, so that the guard processing by the guard range is not performed, and the value is updated as it is. In this manner, the guard processing based on the guard range is not performed on the learning value that is less on the lean side than the region where learning is completed and is positioned on the lean side for the following reason. In a region where the intake air amount is small, a slight change in the air-fuel ratio greatly affects the stability of the operation of the engine 22. The influence on the lean side is particularly large. Such an effect appears more greatly when the engine 22 is started, and the startability of the engine 22 is reduced due to a slight lack of stability. Therefore, to ensure good startability, the learning value on the lean side with a small amount of intake air is updated without correction or guard processing until the learning is completed. By using the value, good startability is ensured. In a hybrid vehicle, the engine is automatically started, and an abnormality is determined that startability is poor. Therefore, by applying such learning value update processing to a hybrid vehicle, good startability of the internal combustion engine in the hybrid vehicle can be ensured.

  According to the control device 60 of the internal combustion engine of the embodiment described above, the guard value is subjected to the guard processing for the learning value that is less in the learning value in the unlearned region than the region in which learning is completed and is located on the lean side. Since updating is performed using the value without performing, it is possible to ensure good startability. In particular, when such a control device 60 for an internal combustion engine is mounted on a hybrid vehicle, it is possible to suppress abnormality determination accompanying a slight decrease in startability. Further, according to the control device 60 of the internal combustion engine of the embodiment, the learning value in the unlearned region other than the learning value located on the lean side is less than the learning value in the learning value in the unlearned region and the amount of intake air is smaller. Since the guard process is performed according to the guard range, it can be updated to a more appropriate value.

  In the control apparatus 60 for the internal combustion engine of the embodiment, only the learning value that is less in the learning value in the unlearned region than the region in which learning has been completed and that is located on the lean side is not subjected to guard processing by the guard range. It is assumed that the guard value is used for the learning value in the other unlearned area, but the learning value in the unlearned area is less than the area where learning is completed. As for the value, the guard processing by the guard range may not be performed even on the rich side.

  In the control apparatus 60 for an internal combustion engine of the embodiment, the guard value is subjected to guard processing for learning values other than the learning value located on the lean side with less intake air amount than the learning completed region among the learning values in the unlearned region. In the learning value in the unlearned area, the learning value located on the lean side is less than the area in which learning has been completed. The learning value other than the learning value located on the lean side is less than the area where learning is completed, and correction processing is performed by multiplying the correction coefficient, etc., and inhaling from the learning value of the learning value in the unlearned area The correction processing may not be performed for a learning value that has a small amount of air and is located on the lean side. In this case, the learning value subjected to the correction process may be out of the guard range.

  The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

1 is a configuration diagram showing an outline of a configuration of an engine system 20 in which a control device 60 for an internal combustion engine as an embodiment of the present invention is incorporated. 4 is a flowchart illustrating an example of a learning value update process executed by a control device 60. It is explanatory drawing explaining the mode of the update of the learning value of an unlearned area | region.

Explanation of symbols

  20 Engine System, 22 Engine, 24 Air Cleaner, 26 Throttle Valve, 28 Fuel Injection Valve, 30 Intake Valve, 32 Spark Plug, 34 Piston, 36 Crankshaft, 38 Purifier, 40 Throttle Motor, 42 Crank Position Sensor, 44 Ignition Coil , 46 Water temperature sensor, 48 Cam position sensor, 50 Throttle valve position sensor, 52 Air-fuel ratio sensor, 54 Oxygen sensor, 56 Variable valve timing mechanism, 60 Control device, 62 CPU, 64 ROM, 66 RAM, 80 Ignition switch, 81 shift Lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor Sa, 88 vehicle speed sensor.

Claims (5)

A control device for an internal combustion engine,
Learning execution means for performing learning regarding the air-fuel ratio in fuel injection control for the internal combustion engine with a plurality of intake air amount regions as a plurality of learning regions;
Of the plurality of learning regions, the learning value of the learning completion region in which learning by the learning execution unit has been completed is the learning value, and learning by the learning execution unit is not completed in the plurality of learning regions. The learning value in the unlearned area and the learning value in the area where the intake air amount is larger than the learning completion area and the learning value on the rich side in the area where the intake air amount is smaller than the learning completion area are based on the learning value in the learning completion area The result of the correction is used as a learning result, and the learning value is used as the learning value for the learning value on the lean side in the learning value in the unlearned region and the amount of intake air is less than the learning completion region among the plurality of learning regions. Learning result adjusting means for adjusting as
Fuel injection control means for executing fuel injection control for the internal combustion engine using the learning result adjusted by the learning result adjusting means;
A control device for an internal combustion engine.   The control device for an internal combustion engine according to claim 1, wherein the correction based on the learning value in the learning completion region is correction within a correction range based on the learning value in the learning completion region.   3. The control device for an internal combustion engine according to claim 2, wherein the correction range is a range that is set as a range of a predetermined deviation from the median value when an average value of the learned values in the learning completion region is a median value.   The learning result adjusting means includes a learning value in an unlearned region among the plurality of learning regions and a rich value in a region having a larger intake air amount than the learning completion region and a region having a smaller intake air amount than the learning completion region. When the learned value is within the correction range, the learning value is adjusted as a learning result. When the learned value is outside the correction range, the learning value is closest to the learned value. 4. The control device for an internal combustion engine according to claim 2, wherein the control device is a means for adjusting a value as a learning result. A control method for an internal combustion engine comprising:
(A) performing learning related to an air-fuel ratio in fuel injection control for the internal combustion engine with a plurality of intake air amount regions as a plurality of learning regions;
(B) The learning value of a learning completion region in which learning has been completed among the plurality of learning regions is used as a learning result, and a learning value of an unlearned region in which learning has not been completed among the plurality of learning regions. As a result of the correction based on the learning value in the learning completed region, the learning value in the region where the intake air amount is larger than the learning completion region and the learning value on the rich side in the region where the intake air amount is smaller than the learning completion region And the learning value for the lean side learning value in a region where the intake air amount is less than the learning completion region among the plurality of learning regions and the learning value in the unlearned region,
(C) A control method for an internal combustion engine, wherein fuel injection control for the internal combustion engine is executed using the learning result.

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