JP2006348874A - Controller for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively suppress catalyst exhaust gas odor even at high altitude, about a controller for an internal combustion engine. <P>SOLUTION: An atmospheric pressure KPA is acquired based on output of an atmospheric pressure sensor (a step 100). Judging whether this atmospheric pressure KPA is smaller than a high altitude judgement value or not (a step 102), in the case that the atmospheric pressure KPA is smaller than the high altitude judgement value, the higher the altitude of a vehicle, the more correction is conducted to increase a target air flow rate at the time of odor suppressing control (steps 104, 106). A target throttle opening at the time of odor suppression is calculated from the corrected target air flow rate. In the odor suppression control, air is supplied to catalyst by opening the throttle during speed reduction fuel cut-off. Thus, the catalyst becomes an oxidation state and generation of hydrogen sulfide is prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine mounted on a vehicle.

Hydrogen sulfide (H ₂ S) may be generated in the exhaust gas of the internal combustion engine of the vehicle. Since hydrogen sulfide has a strange odor, if hydrogen sulfide is generated in the exhaust gas, it may not be noticed during traveling, but there may be a odor (catalyst exhaust odor) outside the vehicle after stopping. This hydrogen sulfide is generated by reducing the sulfur adsorbed by the catalyst that purifies the exhaust gas. When the internal combustion engine is operated at a rich air-fuel ratio, the catalyst is reduced by the unburned fuel in the exhaust gas and hydrogen sulfide is easily generated. Therefore, when the vehicle stops immediately after that, the catalyst The exhaust odor tends to be strong.

  In Japanese Utility Model Publication No. 63-79425, in order to suppress the catalyst exhaust odor as described above, secondary air is introduced into the exhaust passage when the vehicle is decelerated, and the catalyst is oxidized by the secondary air. A technique for suppressing the generation of hydrogen sulfide is disclosed.

Japanese Utility Model Publication No. 63-79425 Japanese Utility Model Publication No. 63-60047 JP-A-6-299894 JP-A-9-49628

  By the way, in the high altitude where the atmospheric pressure is low, since the air density is small, oxygen is also diluted. For this reason, when traveling on high altitudes, it becomes difficult to sufficiently oxidize the entire catalyst during deceleration of the vehicle, so that a catalyst exhaust odor is more likely to occur than on flat ground.

  However, since the conventional technology did not consider the ease with which the catalyst exhaust odor is generated at high altitudes, even if the catalyst exhaust odor is suppressed on flat ground, the catalyst exhaust odor may be generated when traveling on high altitudes. there were.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a control device for an internal combustion engine that can effectively suppress the catalyst exhaust odor even at high altitudes.

In order to achieve the above object, a first invention is a control device for an internal combustion engine,
A catalyst provided in an exhaust passage of an internal combustion engine mounted on a vehicle and purifying exhaust gas;
An altitude index detecting means for detecting a vehicle altitude or an index correlated with the vehicle altitude;
Parameter correction means for performing correction control for correcting a control parameter related to the total amount of oxygen supplied to the catalyst during deceleration of the internal combustion engine in a direction to increase the total amount as the vehicle altitude increases.
It is characterized by providing.

The second invention is the first invention, wherein
High altitude determination means for performing high altitude determination based on the detection value of the altitude index detection means,
The parameter correction means performs the correction control when the highland determination is affirmed.

The third invention is the first or second invention, wherein
The parameter correction means includes means for performing the correction control so that the control parameter continuously changes according to the vehicle altitude.

According to a fourth invention, in any one of the first to third inventions,
Fuel cut means for performing fuel cut during the deceleration,
The control parameter is a throttle opening during fuel cut,
The increasing direction is a direction in which the throttle opening is increased.

The fifth invention is the fourth invention, wherein
An accelerator position sensor that detects that the accelerator pedal has been depressed;
And a throttle return means for reducing the throttle opening when it is detected that the accelerator pedal is depressed when the parameter correction means is corrected to increase the throttle opening. .

According to a sixth invention, in any one of the first to fifth inventions,
Fuel cut means for performing fuel cut during the deceleration,
The control parameter is a start delay time from when the fuel cut execution condition is satisfied to when the fuel cut is started,
The increasing direction is a direction for shortening the start delay time.

According to a seventh invention, in any one of the first to sixth inventions,
Fuel cut means for performing fuel cut during the deceleration,
The control parameter is a fuel cut return rotational speed,
The increasing direction is a direction in which the fuel cut return rotational speed is decreased.

Further, an eighth invention is any one of the first to seventh inventions,
A secondary air supply means for supplying secondary air to the catalyst during the deceleration;
The control parameter is a supply amount of the secondary air,
The increasing direction is a direction in which the supply amount of the secondary air is increased.

  According to the first aspect of the present invention, the control parameter related to the total amount of oxygen supplied to the catalyst during deceleration of the internal combustion engine can be corrected so that the total amount increases as the vehicle altitude increases. For this reason, even in a high altitude where oxygen is lean, the catalyst can be sufficiently oxidized during deceleration of the internal combustion engine, so that the catalyst exhaust odor can be effectively suppressed.

  According to the second invention, it is possible to perform the correction control only when the vehicle is on a high ground, and to avoid performing the correction control when the vehicle is on a flat ground.

  According to the third aspect of the invention, the control parameter can be corrected without excess or deficiency according to the vehicle altitude. For this reason, it is possible to reliably suppress the catalyst exhaust odor at high altitudes of any altitude, and to suppress the deterioration of the catalyst to the minimum.

  According to the fourth invention, the above effect can be achieved without adding a special mechanical configuration for supplying oxygen to the catalyst.

  According to the fifth aspect of the present invention, it is possible to reliably prevent generation of torque that is greater than the driver's request immediately after resumption of fuel injection when forced recovery from the deceleration fuel cut is performed.

  According to the sixth aspect of the present invention, the above effect can be achieved without adding a special mechanical configuration for supplying oxygen to the catalyst.

  According to the seventh aspect, the above-described effect can be achieved without adding a special mechanical configuration for supplying oxygen to the catalyst.

  According to the eighth aspect of the invention, it is possible to achieve the above effect while reliably preventing the drive feeling from being affected when the correction control is performed.

Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the element which is common in each figure, and the overlapping description is abbreviate | omitted.
Embodiment 1 FIG.
[Description of system configuration]
FIG. 1 is a diagram for explaining a system configuration according to the first embodiment of the present invention. As shown in FIG. 1, the system of the present embodiment includes an internal combustion engine 10 that serves as power for the vehicle. An intake passage 12 and an exhaust passage 14 communicate with the internal combustion engine 10.

  An air flow meter 16 for detecting the amount of air flowing through the intake passage 12, that is, the amount of intake air flowing into the internal combustion engine 10 is disposed in the intake passage 12. A throttle valve 18 is disposed downstream of the air flow meter 16. The throttle valve 18 is an electronically controlled valve that is driven by a throttle motor 20 based on an accelerator opening or the like. In the vicinity of the throttle valve 18, a throttle position sensor 22 for detecting the throttle opening is disposed. The accelerator opening is detected by an accelerator position sensor 24 provided in the vicinity of the accelerator pedal.

  The internal combustion engine 10 is a multi-cylinder engine having a plurality of cylinders, and FIG. 1 shows a cross section of one of the cylinders. Each cylinder included in the internal combustion engine 10 is provided with an intake port that communicates with the intake passage 12 and an exhaust port that communicates with the exhaust passage 14. A fuel injection valve 26 for injecting fuel into the intake port is disposed in the intake port. The intake port and the exhaust port are respectively provided with an intake valve 28 and an exhaust valve 29 for making the intake passage 12 and the cylinder or the exhaust passage 14 and the cylinder conductive or closed. Each cylinder is provided with a spark plug 30 that emits a spark for igniting the air-fuel mixture in the cylinder. The internal combustion engine 10 is not limited to the configuration shown in the figure, and may be, for example, a system in which fuel is directly injected into a cylinder.

  Each cylinder of the internal combustion engine 10 includes a cylinder 32 and a piston 34. A crank angle sensor 38 for detecting the rotation angle of the crankshaft 36 is attached in the vicinity of the crankshaft 36 that is rotationally driven by the reciprocating motion of the piston 34. The crank angle sensor 38 is a sensor that reverses the Hi output and the Lo output each time the crankshaft rotates by a predetermined rotation angle. According to the output of the crank angle sensor 38, it is possible to detect the rotational position and rotational speed of the crankshaft, and further the engine rotational speed NE and the like.

  An upstream catalyst 40 and a downstream catalyst 42 for purifying exhaust gas are arranged in series in the exhaust passage 14 of the internal combustion engine 10. The upstream catalyst 40 is a relatively small capacity catalyst generally called a start converter (SC). The downstream catalyst 42 is a catalyst having a relatively large capacity generally called an underfloor converter (UF). The upstream catalyst 40 is disposed at a position closer to the exhaust port than the downstream catalyst 42, and exhaust gas having a high temperature flows in. Therefore, the upstream catalyst 40 is warmed up in a short time from the start and has good exhaust purification performance. Demonstrate. On the other hand, the downstream catalyst 42 takes a longer time to warm up than the upstream catalyst 40, but has a large capacity, and thus exhibits excellent exhaust purification performance once warmed up.

  An air-fuel ratio sensor 44 for detecting the exhaust air-fuel ratio at that position is disposed upstream of the upstream catalyst 40. Further, an oxygen sensor 46 that generates a signal corresponding to whether the air-fuel ratio at that position is rich or lean is disposed between the upstream catalyst 40 and the downstream catalyst 42.

  1 includes a temperature sensor 47 for detecting the temperature of the upstream catalyst 40, a temperature sensor 48 for detecting the temperature of the downstream catalyst 42, an atmospheric pressure sensor 49 for detecting the atmospheric pressure KPA, and an ECU (Electronic Control Unit) 50. The ECU 50 is connected to the various sensors and actuators described above. The ECU 50 can control the operating state of the internal combustion engine 10 based on those sensor outputs.

[Features of Embodiment 1]
Next, an outline of the operation of the system in the present embodiment will be described.
The system of the present embodiment is a process for stopping fuel injection when the internal combustion engine 10 is decelerated (when the ECU 50 determines that the accelerator is OFF) and the engine speed NE is greater than or equal to a set value, that is, fuel cut. Execute (F / C). By executing the fuel cut, the fuel consumption can be improved and the catalyst can be protected. The fuel cut at the time of deceleration is hereinafter referred to as “deceleration fuel cut”.

  Further, the system of the present embodiment performs fuel increase control for increasing the fuel injection amount so that the air-fuel ratio becomes richer than the stoichiometric air-fuel ratio when the load is high. When the fuel increase control is performed, the upstream catalyst 40 and the downstream catalyst 42 are reduced by the unburned fuel in the exhaust gas.

  When the upstream catalyst 40 and the downstream catalyst 42 are in a reduced state and are at a high temperature, the sulfur content adsorbed on the upstream catalyst 40 and the downstream catalyst 42 is reduced, so that hydrogen sulfide is easily generated. When hydrogen sulfide is generated, a catalyst exhaust odor may be felt inside and outside the vehicle when the vehicle stops.

  In the present embodiment, in order to prevent the generation of the catalyst exhaust odor, when conditions that facilitate the generation of hydrogen sulfide are satisfied, that is, there is a fuel increase history and the upstream catalyst 40 and the downstream catalyst 42 become high temperature. If so, odor suppression control is performed to increase the intake air amount by opening the throttle valve 18 during execution of the deceleration fuel cut. When this odor suppression control is performed, the amount of air flowing through the exhaust passage 14 increases, so that a large amount of oxygen is supplied to the upstream catalyst 40 and the downstream catalyst 42. As a result, since the upstream catalyst 40 and the downstream catalyst 42 can be sufficiently oxidized during the deceleration fuel cut, the generation of hydrogen sulfide can be suppressed.

  Before the vehicle stops, the vehicle is always decelerated, that is, the internal combustion engine 10 is decelerated. Therefore, by performing the odor suppression control while the internal combustion engine 10 is decelerating, the catalyst exhaust odor when the vehicle is stopped can be effectively suppressed.

  On the other hand, when there is no fuel increase history or when the upstream catalyst 40 and the downstream catalyst 42 are not at a high temperature, it is difficult to generate hydrogen sulfide, so the necessity of performing the odor suppression control is low. Rather, in this case, in order to prevent the deterioration of the upstream catalyst 40 and the downstream catalyst 42, it is preferable to reduce the amount of oxygen supplied to the upstream catalyst 40 and the downstream catalyst 42 as much as possible. Therefore, in the present embodiment, the odor suppression control is performed during the deceleration fuel cut only when there is a fuel increase history and the upstream catalyst 40 and the downstream catalyst 42 are at a high temperature, and in other cases, The throttle valve 18 was closed during the deceleration fuel cut so that the oxygen supply amount to the upstream catalyst 40 and the downstream catalyst 42 was reduced.

  By performing the odor suppression control described above, the catalyst exhaust odor can be reliably suppressed on flat ground. However, at high altitude where oxygen is lean, the total amount of oxygen supplied to the upstream catalyst 40 and the downstream catalyst 42 during odor suppression control is reduced. As a result, the upstream catalyst 40 and the downstream catalyst 42 as a whole are not sufficiently oxidized, and a situation in which the downstream catalyst 40 is not sufficiently oxidized is likely to occur. For this reason, the catalyst exhaust odor may not be suppressed at high altitudes even if the odor suppression control is performed under the same control conditions as the low altitude flat ground.

  Therefore, in the present embodiment, correction is performed to increase the throttle opening during execution of odor suppression control as the vehicle altitude is higher. As a result, the higher the vehicle altitude, the larger the volumetric flow rate of the air flowing through the exhaust passage 14 during the execution of the odor suppression control. You can make up for the minute. Therefore, the catalyst exhaust odor can be reliably suppressed even at high altitudes. Further, it is possible to suppress the deterioration of the upstream catalyst 40 and the downstream catalyst 42 as compared with the case where the oxygen supply amount during execution of the odor suppression control is uniformly increased regardless of whether it is a flat land or a highland.

[Specific Processing in Embodiment 1]
2 and 4 are flowcharts of routines executed by the ECU 50 in the present embodiment in order to realize the above functions. These routines are executed every predetermined time (for example, every 8 msec). The routine shown in FIG. 2 is a routine for correcting the target flow rate of the air flowing through the exhaust passage 14 during the odor suppression control according to the vehicle altitude. In the ECU 50, a predetermined odor suppression reference flow rate represented by a volume flow rate is set in advance as a target flow rate. The reference flow rate at the time of odor suppression is a flow rate that is necessary and sufficient for effectively performing odor suppression control on a flat ground.

  According to the routine shown in FIG. 2, first, the atmospheric pressure KPA is acquired based on the output of the atmospheric pressure sensor 49 (step 100). In the present embodiment, the atmospheric pressure KPA is used as an index that correlates with the vehicle altitude to perform processing according to the vehicle altitude.

  Next, it is determined whether or not the atmospheric pressure KPA is smaller than the high altitude determination value (step 102). As a result, when it is recognized that the atmospheric pressure KPA is equal to or higher than the highland determination value, it can be determined that the vehicle is on a flat ground. In this case, since the target flow rate does not need to be corrected, the target flow rate is not changed, and the preset reference flow rate during odor suppression becomes the target flow rate as it is.

  On the other hand, if it is determined in step 102 that the atmospheric pressure KPA is smaller than the high altitude determination value, it can be determined that the vehicle is in the high altitude. In this case, since the target flow rate needs to be corrected, a correction coefficient for correcting the target flow rate is calculated (step 104). As shown in FIG. 3, the ECU 50 stores a map in which the correction coefficient is determined in relation to the atmospheric pressure KPA. Here, the correction coefficient (> 1) is calculated by referring to the map. Then, a value obtained by multiplying the calculated correction coefficient by the reference flow rate during odor suppression is set as the target flow rate (step 106).

  In the map shown in FIG. 3, the correction coefficient is continuously increased as the atmospheric pressure KPA decreases. As a result, the target flow rate can be continuously increased as the atmospheric pressure KPA decreases, that is, as the vehicle altitude increases, so an optimal target flow rate with no excess or deficiency is set according to the degree of oxygen dilution at high altitude. can do.

  The routine shown in FIG. 4 is a routine for performing odor suppression control. In the routine shown in FIG. 4, it is first determined whether or not a deceleration fuel cut is being executed (step 108). The ECU 50 monitors the establishment of the deceleration fuel cut execution condition by another routine. The conditions for executing the deceleration fuel cut are that the throttle opening is the reference deceleration opening (fully closed or substantially fully closed) and the engine speed NE is equal to or greater than the set value. That is, when it is detected that the throttle valve 18 is closed to the reference deceleration opening degree by releasing the accelerator pedal, and the engine speed NE is equal to or higher than the set value, the deceleration fuel cut is performed. Be started. When the deceleration fuel cut is started, the deceleration F / C flag is set to 1 to indicate that the deceleration fuel cut is in progress. In step 108, it is determined based on the value of the deceleration F / C flag whether or not the deceleration fuel cut is being executed. As a result, when it is recognized that the deceleration fuel cut is not being executed, the odor suppression control is not performed and the current processing cycle is terminated.

  On the other hand, if it is determined in step 108 that the deceleration fuel cut is being performed, then it is determined whether or not there is a fuel increase history (step 110). The presence / absence of the fuel increase history is determined based on the value of the increase history flag. The increase history flag is set to 1 to indicate that the upstream catalyst 40 and the downstream catalyst 42 are in the reduction state when the fuel increase control is performed at a high load or the like. The increase history flag is reset to 0 when the conditions that the upstream catalyst 40 and the downstream catalyst 42 are sufficiently oxidized after the fuel increase control is completed. For example, the increase history flag is reset when the integrated value of the intake air amount after the end of the fuel increase control exceeds a predetermined value.

  If it is determined in step 110 that there is no fuel increase history, it can be determined that hydrogen sulfide is unlikely to be generated. In this case, odor suppression control is not performed, and the current processing cycle is terminated. As a result, normal deceleration fuel cut with the throttle valve 18 closed to the reference deceleration opening degree is continued.

  On the other hand, if it is recognized in step 110 that there is a history of fuel increase, whether or not the temperatures of the upstream catalyst 40 and the downstream catalyst 42 are high enough to generate hydrogen sulfide is determined next. A determination is made (step 112). This determination is made based on the outputs of the temperature sensors 47 and 48. As a result of this determination, when it is recognized that the upstream catalyst 40 and the downstream catalyst 42 are not at a high temperature, it can be determined that hydrogen sulfide is hardly generated. In this case, odor suppression control is not performed, and the current processing cycle is terminated. As a result, normal deceleration fuel cut with the throttle valve 18 closed to the reference deceleration opening degree is continued.

  Thus, according to the processing of steps 110 and 112 described above, when it is difficult to generate hydrogen sulfide, the odor suppression control is not performed. For this reason, since unnecessary supply of oxygen to the upstream catalyst 40 and the downstream catalyst 42 can be avoided, it is possible to prevent the deterioration of the upstream catalyst 40 and the downstream catalyst 42 from proceeding.

On the other hand, if it is determined in step 112 that the upstream catalyst 40 and the downstream catalyst 42 are at a high temperature, the condition that hydrogen sulfide is likely to be generated is combined with the determination in step 110 that there is a fuel increase history. It can be judged that Therefore, in this case, odor suppression control is performed as follows. First, a target throttle opening that can realize the target flow rate set by the routine processing shown in FIG. 2 is calculated (step 114).
As shown in FIG. 5, the ECU 50 stores a map that defines the relationship between the target flow rate and the throttle opening that can achieve this at a predetermined engine speed NE. Here, the target throttle opening is calculated by referring to the map.

  In the map shown in FIG. 5, four maps corresponding to the amount of deposit (carbon deposit) attached to the intake valve 28 are shown. As the deposit amount increases, the substantial opening width of the intake valve 28 decreases, so that a larger throttle opening is required to ensure the same intake air amount. In the system of the present embodiment, the deposit amount is learned by a known method, and one of the four maps is used according to the current deposit amount. In step 114, the target throttle opening is calculated with reference to the map corresponding to the current deposit amount among the four maps.

  Next, the throttle motor 20 is driven to open the throttle valve 18 in order to realize the target throttle opening calculated in the process of step 114 (step 116). Thereby, the air flow rate of the exhaust passage 14 is controlled to the target flow rate. This target flow rate is corrected to increase in accordance with the vehicle altitude by the processing of the routine shown in FIG. For this reason, by realizing the target flow rate, it is possible to supply an amount of oxygen that can sufficiently oxidize the entire upstream catalyst 40 and downstream catalyst 42 even in a high altitude where oxygen is lean. As a result, generation of catalyst exhaust odor can be reliably suppressed even at high altitudes.

  In the first embodiment described above, the atmospheric pressure KPA is detected by the dedicated atmospheric pressure sensor 49, but the method for detecting the atmospheric pressure KPA is not limited to this. For example, a method of detecting the atmospheric pressure KPA by taking in an output of an intake pressure sensor (not shown) arranged in the intake passage 12 when the engine is stopped, or a target air-fuel ratio of the exhaust air-fuel ratio detected by the air-fuel ratio sensor 44. A method of learning the atmospheric pressure KPA from the deviation amount with respect to may be used.

  Further, in the first embodiment described above, the process corresponding to the vehicle altitude is performed using the fact that the atmospheric pressure KPA correlates with the vehicle altitude, but the present invention is not limited to this. For example, in the present invention, the vehicle altitude itself may be detected by using GPS (Global Positioning System) or the like.

  Further, in the first embodiment described above, the high altitude determination is first performed, and only when the high altitude determination is affirmed, the throttle opening during the odor suppression control is increased and corrected. The determination may not be performed. For example, the throttle opening at the time of odor suppression control may be corrected by always multiplying a correction coefficient according to the vehicle altitude from flat to high.

  Moreover, in Embodiment 1 mentioned above, although the throttle opening at the time of odor suppression control is correct | amended so that it may increase continuously according to vehicle height, in this invention, it is stepwise according to vehicle height. You may correct | amend so that it may increase.

  Further, in the first embodiment described above, whether or not the catalyst is in the reduction state is determined based on the presence or absence of the fuel increase history, but in the present invention, this determination is performed by a method other than the presence or absence of the fuel increase history. May be performed.

  In the first embodiment described above, the atmospheric pressure sensor 49 is the “altitude index detecting means” in the first invention, and the throttle opening during the deceleration fuel cut is the “control parameter” in the first invention. The direction in which the throttle opening is increased corresponds to the “increase direction” in the first invention. Further, the “parameter correction means” in the first aspect of the present invention is realized by the ECU 50 executing the processing of steps 104, 106, 114 and 116 described above. Further, the ECU 50 executes the processing of step 102, thereby realizing the “high altitude determination means” in the second invention. The ECU 50 executes fuel cut when the internal combustion engine 10 is decelerated, whereby the “fuel cut means” according to the fourth aspect of the present invention is realized.

Embodiment 2. FIG.
[Features of Embodiment 2]
Next, the second embodiment of the present invention will be described with reference to FIG. 6. The description will focus on the differences from the first embodiment described above, and the description of the same matters will be omitted or simplified. . The system of the present embodiment can be realized by causing the ECU 50 to execute a routine shown in FIG. 6 described later in place of the routine shown in FIG. 4 in the system of the first embodiment described above.

  In the system that performs the deceleration fuel cut as in the first embodiment described above, generally, when the driver requests acceleration during the execution of the deceleration fuel cut, that is, when the accelerator pedal is depressed, the acceleration is performed. In order to meet the demand, the fuel injection is resumed and the fuel cut state is forcibly returned to the output generation state. When the odor suppression control is not performed during the deceleration fuel cut, the throttle valve 18 is closed to the reference deceleration opening (fully closed or substantially fully closed), so that the internal combustion engine immediately after the restart of fuel injection at the forced return The torque of 10 is small.

  On the other hand, when the odor suppression control is performed during the deceleration fuel cut, the intake air amount is increased by opening the throttle valve 18, so that the torque of the internal combustion engine 10 immediately after the restart of fuel injection is large. . As described above, in the first embodiment, the throttle opening at the time of odor suppression control is increased according to the vehicle altitude, so that the torque immediately after resuming fuel injection increases as the altitude increases. For this reason, a situation may occur in which excessive torque is generated in comparison with the driver's request during forced recovery.

  Therefore, in this embodiment, when the throttle valve 18 is opened by the odor suppression control during the deceleration fuel cut, if the accelerator pedal is depressed even slightly, the throttle opening is returned to the reference deceleration opening. As a result, when forcibly returning, the throttle valve 18 can be closed to the opening at the time of normal deceleration fuel cut before resuming fuel injection, so that it is possible to reliably prevent an excessive torque immediately after resuming fuel injection. Can do.

[Specific Processing in Second Embodiment]
FIG. 6 is a flowchart of a routine executed by the ECU 50 in the present embodiment in order to realize the above function. This routine is similar to the routine shown in FIG. 4 except that steps 118 and 120 are inserted at the appropriate locations. In FIG. 6, the same steps as those shown in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  The routine shown in FIG. 6 determines whether or not the accelerator pedal has been depressed after step 112 for determining whether or not the upstream catalyst 40 and the downstream catalyst 42 are at a high temperature as compared with the routine shown in FIG. Step 118 is inserted. Whether or not the accelerator pedal has been depressed is determined based on the output of the accelerator position sensor 24.

  If it is determined in step 118 that the accelerator pedal is not depressed, the processing of steps 114 and 116 is executed in the same manner as in the routine shown in FIG. Done. That is, while the accelerator pedal is not depressed, the same processing as in the first embodiment is executed.

  On the other hand, if it is determined in step 118 that the accelerator pedal has been depressed even slightly, the throttle opening at the time of normal deceleration fuel cut, that is, the reference deceleration opening is set as the target throttle opening (step 120). In this case, next, the throttle motor 20 is driven to realize the target throttle opening (step 116), and the throttle valve 18 is closed to the reference deceleration opening. In this way, when the throttle valve 18 is closed to the reference deceleration opening, when the accelerator pedal is further depressed and forced recovery from the deceleration fuel cut is performed, excessive torque immediately after the fuel injection is resumed. Can be reliably prevented.

  In the second embodiment described above, the “throttle return means” according to the fifth aspect of the present invention is realized by the ECU 50 executing the processing of steps 118 and 120 described above.

Embodiment 3 FIG.
[Features of Embodiment 3]
Next, the third embodiment of the present invention will be described with reference to FIG. 7 to FIG. 9. The description will focus on the differences from the first embodiment described above, and the description of the same matters will be omitted. Or simplify. The system of the present embodiment can be realized by causing the ECU 50 to execute a routine shown in FIG. 7 described later using the hardware configuration shown in FIG.

  In the above-described first embodiment, when the vehicle is at a high altitude, the amount of oxygen that is diluted in order to sufficiently secure the amount of oxygen supplied to the upstream catalyst 40 and the downstream catalyst 42 that are executing the odor suppression control is determined as the throttle opening. This is compensated for by increasing the air flow rate, that is, by increasing the air flow rate.

  On the other hand, in the present embodiment, when the vehicle is at high altitude, the duration of the odor suppression control is made longer than that when the vehicle is on flat ground, without increasing the air flow rate, so that the upstream catalyst 40 and the downstream catalyst 42 are moved. It was decided to secure a sufficient oxygen supply amount. In other words, the amount of oxygen diluting at high altitudes was compensated by increasing the air supply time.

  Since the odor suppression control is performed during the deceleration fuel cut, the duration of the odor suppression control can be increased by increasing the duration of the deceleration fuel cut. In the present embodiment, the duration of the deceleration fuel cut is increased by shortening the start delay time of the deceleration fuel cut as the vehicle height increases.

  In a system that performs a deceleration fuel cut, a predetermined start delay time is generally set. That is, the deceleration fuel cut is not started immediately after the execution condition is satisfied, but is started after the start delay time elapses for reasons such as prevention of hunting. Therefore, if the start delay time is shortened, the start time of the deceleration fuel cut is advanced, so that the duration of the deceleration fuel cut can be lengthened.

  In this embodiment, in order to further increase the duration of the deceleration fuel cut, in addition to the method of reducing the start delay time, a method of lowering the fuel cut return rotational speed is also used. In a system that performs deceleration fuel cut, a predetermined return rotational speed is generally set. When the engine speed NE decreases to the return speed during the deceleration fuel cut, the deceleration fuel cut is terminated, that is, the fuel injection is resumed. Therefore, if the fuel cut return rotational speed is lowered, the end time of the deceleration fuel cut is delayed, so that the duration of the deceleration fuel cut can be lengthened.

  In the present embodiment, the process of reducing the fuel cut return rotational speed is not always performed at high altitude, but is performed only when the vehicle brake is activated during the deceleration fuel cut. When the vehicle brake is activated, the reduction in the engine speed NE is accelerated, so that the deceleration fuel cut duration is shortened. In this case, by reducing the fuel cut return rotational speed, the shortening of the fuel cut duration can be offset, and a sufficient deceleration fuel cut duration can be ensured.

[Specific Processing in Embodiment 3]
FIG. 7 is a flowchart of a routine executed by the ECU 50 in the present embodiment in order to realize the above function. This routine is executed every predetermined time. In FIG. 7, the same steps as those shown in FIGS. 2 and 4 described above are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  According to the routine shown in FIG. 7, first, it is determined whether or not the execution condition for the deceleration fuel cut is satisfied (step 122). Specifically, it is determined whether or not the throttle opening is closed to a reference deceleration opening (fully closed or substantially fully closed) and the engine speed NE is equal to or higher than a set value. If it is recognized that the deceleration fuel cut execution condition is not satisfied, the current processing cycle is terminated.

  On the other hand, when the execution condition of the deceleration fuel cut is confirmed in the above step 122, it is next determined whether or not there is a fuel increase history in order to determine whether or not hydrogen sulfide is likely to be generated. Step 110) and determination of whether the upstream catalyst 40 and the downstream catalyst 42 are at a high temperature (step 112) are sequentially performed.

  When it is recognized in step 110 that there is no fuel increase history, or when it is found in step 112 that the upstream catalyst 40 and the downstream catalyst 42 are not at a high temperature, hydrogen sulfide is likely to be generated. Therefore, it is not necessary to perform odor suppression control. Therefore, in this case, the normal deceleration fuel cut is executed after waiting for the elapsed time after the deceleration fuel cut execution condition is satisfied to reach the reference start delay time (step 124).

  On the other hand, if it is recognized in step 110 that there is a history of fuel increase, and if it is found in step 112 that the upstream catalyst 40 and the downstream catalyst 42 are at a high temperature, hydrogen sulfide is generated. It can be determined that it is easy to do. In this case, next, the atmospheric pressure KPA is acquired (step 100), and it is further determined whether or not the atmospheric pressure KPA is smaller than the high altitude determination value (step 102).

  If it is determined in step 102 that the atmospheric pressure KPA is smaller than the high altitude determination value, it can be determined that the vehicle is in the high altitude. In this case, next, the set value of the deceleration fuel cut start delay time is shortened (step 128). As shown in FIG. 8, the ECU 50 stores a map in which the deceleration fuel cut start delay time is determined in relation to the atmospheric pressure KPA. Here, the reference value of the deceleration fuel cut start delay time is changed to a value shorter than the reference start delay time by referring to the map. In the map shown in FIG. 8, the deceleration fuel cut start delay time is continuously shortened as the atmospheric pressure KPA is smaller, that is, as the vehicle altitude is higher.

  On the other hand, when it is recognized in step 102 that the atmospheric pressure KPA is equal to or higher than the highland determination value, it can be determined that the vehicle is on a flat ground. On flat ground, even if the odor suppression control is performed without reducing the start delay time of the deceleration fuel cut, a sufficient odor suppression effect can be obtained. Therefore, in this case, the set value of the start delay time is not changed and remains at the reference start delay time.

  In the routine shown in FIG. 7, it is next determined whether or not the elapsed time since the execution condition of the deceleration fuel cut is satisfied has reached the set start delay time (step 130). If it is recognized that the start delay time has elapsed, a deceleration fuel cut is executed (step 132). When the deceleration fuel cut is started in this way, odor suppression control for opening the throttle valve 18 to the odor suppression reference opening is performed (step 134). In this embodiment, since the start delay time is shortened according to the vehicle height as described above, the deceleration fuel cut is started earlier as the vehicle height is higher, and therefore the odor suppression control is also started earlier. As a result, the amount of air supplied to the upstream catalyst 40 and the downstream catalyst 42 can be increased earlier as the vehicle altitude is higher. For this reason, even in a highland where oxygen is lean, an amount of oxygen that can sufficiently oxidize the entire upstream catalyst 40 and downstream catalyst 42 can be supplied. Therefore, even in high altitudes, generation of hydrogen sulfide that causes catalyst exhaust odor can be sufficiently suppressed.

  When the odor suppression control is started, it is next determined whether or not the driver has stepped on the brake pedal (step 136). The presence or absence of depression of the brake pedal can be determined by a known method, for example, a method for determining based on the engine speed NE or the speed at which the vehicle speed decreases, or a method for determining based on a signal for turning on the brake lamp.

  If it is determined in step 136 that the brake pedal is depressed, the set value of the fuel cut return rotational speed is lowered (step 138). As shown in FIG. 9, the ECU 50 stores a map in which the fuel cut return rotational speed is determined in relation to the atmospheric pressure KPA. Here, by referring to the map, the set value of the fuel cut return rotational speed is changed to a value smaller than the reference fuel cut return rotational speed. In the map shown in FIG. 9, the lower the atmospheric pressure KPA, that is, the higher the vehicle altitude, the lower the fuel cut return rotational speed.

  On the other hand, when the depression of the brake pedal is not recognized in step 136, the set value of the fuel cut return rotational speed is not lowered and is kept at the reference fuel cut return rotational speed.

  In the routine shown in FIG. 7, it is next determined whether or not the engine speed NE has decreased to the fuel cut return speed (step 140). As a result, when it is recognized that the engine speed NE is smaller than the fuel cut return speed, it can be determined that the condition for ending the deceleration fuel cut is satisfied. In this case, the deceleration fuel cut is terminated (step 142), and fuel injection is resumed.

  In the present embodiment, as described above, when the brake pedal is depressed while the odor suppression control is performed, the fuel cut return rotational speed is lowered from the reference value, so the fuel cut period is extended. The As a result, the shortening of the deceleration fuel cut duration due to the effect of the vehicle brake operation is offset, and the duration of the deceleration fuel cut and thus the duration of the odor suppression control can be sufficiently secured. In this case, the higher the vehicle altitude, the lower the fuel cut return rotational speed, and the longer the duration of the odor suppression control. For this reason, the effect fall of the odor suppression control by the influence of the oxygen dilution in a highland can also be offset. For this reason, in this embodiment, the catalyst exhaust odor can be obtained even when there are two overlapping conditions that weaken the effect of odor suppression control, such as when the brake pedal is depressed at a high altitude where oxygen is lean. Can be sufficiently suppressed.

  By the way, in Embodiment 3 described above, the reduction in the fuel cut return rotational speed is performed only when the brake pedal is depressed. However, the present invention is not limited to this. Accordingly, the fuel cut return rotational speed may be lowered.

  Further, in the above-described third embodiment, as a method for increasing the duration of the odor suppression control at high altitude, a method for shortening the start delay time of the deceleration fuel cut and a method for reducing the fuel cut return rotational speed are used in combination. However, only one of these may be used.

  In the above-described third embodiment, the start delay time and the fuel cut return rotational speed are the “control parameter” in the first aspect of the invention, in which the start delay time is reduced and the fuel cut return rotational speed is reduced. This corresponds to the “increase direction” in the first invention. Further, the ECU 50 executes the processing of steps 128 and 138, thereby realizing the “parameter correcting means” in the first invention. Further, the “fuel cut means” in the sixth and seventh aspects of the present invention is realized by the ECU 50 executing fuel cut when the internal combustion engine 10 is decelerated.

  Note that the processing of shortening the start delay time or reducing the fuel cut return rotational speed peculiar to the third embodiment may be performed in combination with the first or second embodiment.

Embodiment 4 FIG.
Next, the fourth embodiment of the present invention will be described with reference to FIG. 10 to FIG. 12. The difference from the first embodiment will be mainly described, and the same matters will be described. Is omitted or simplified.

[Description of system configuration]
FIG. 10 is a diagram for explaining a system configuration according to the fourth embodiment of the present invention. In FIG. 10, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  As shown in FIG. 10, the system of the fourth embodiment further includes secondary air supply means for supplying secondary air to the exhaust passage 14 in addition to the system configuration of the first embodiment. Hereinafter, the configuration of the secondary air supply means will be described.

  An injection hole 51 communicates with the exhaust passage 14. The injection hole 51 is a conduit for introducing secondary air into the exhaust passage 14. The injection hole 51 communicates with the air pipe 52. The air pipe 52 includes a valve unit 54 in the middle thereof. The air pipe 52 is connected to an air pump 56 at its end. The air pump 56 can suck air through the air filter 58 and send the air to the air pipe 52 as secondary air. The secondary air sent to the air pipe 52 is supplied to the upstream catalyst 40 and the downstream catalyst 42 through the injection hole 51 and the exhaust passage 14.

  The valve unit 54 includes an air switching valve 62 and a check valve 64. The air switching valve 62 is a diaphragm type negative pressure drive valve. The air switching valve 62 communicates with the intake passage 12 via a VSV (Vacuum Switching Valve) 66. The air switching valve 62 is opened when negative pressure in the intake passage 12 is supplied via the VSV 66, and is a diaphragm type that maintains the closed state when the negative pressure is not supplied. A valve mechanism 68 is provided. Therefore, in the system according to the present embodiment, the air switching valve 62 is turned on by turning on the VSV 66 (conducting state), and the air switching valve 62 is turned off (cut off) by turning the VSV 66 off. Can be set in a shut-off state. The VSV 66 and the air pump 56 described above are each connected to the ECU 50.

  The operation of the air pump 56 and the state of the VSV 66 are controlled in conjunction. That is, when the air pump 56 is operated, the VSV 66 is set to an on state, and the air switching valve 62 is set to a conductive state. When the operation of the air pump 56 is stopped, the VSV 66 is set to an off state and the air switching valve 62 is set to a cutoff state. Therefore, when the air pump 56 is operated, the secondary air is supplied to the exhaust passage 14. That is, the operation time of the air pump 56 corresponds to the supply time of the secondary air to the exhaust passage 14 and further corresponds to the secondary air supply amount to the upstream catalyst 40 and the downstream catalyst 42.

  The check valve 64 is a valve mechanism that allows only a forward fluid flow from the air pump 56 toward the exhaust passage 14 and prevents a reverse flow. The check valve 64 is provided to prevent high-temperature exhaust gas from flowing backward from the exhaust passage 14 side to the air pump 56 side when an open failure occurs in the air switching valve 62.

[Features of Embodiment 4]
In the embodiment described above, the throttle valve 18 is opened as a method of supplying air for oxidizing the upstream catalyst 40 and the downstream catalyst 42 when odor suppression control is performed during the deceleration fuel cut. On the other hand, in the present embodiment, the throttle valve 18 is not opened, and the secondary air is supplied to the exhaust passage 14 to secure the amount of air for oxidizing the upstream catalyst 40 and the downstream catalyst 42. It is said. In this embodiment, in order to offset the influence of oxygen dilution at high altitude, correction is performed to increase the supply amount of secondary air as the vehicle altitude increases.

  In the system shown in FIG. 10, since the secondary air is supplied at a constant volume flow rate per unit time when the air pump 56 is operated, the total supply amount of the secondary air is proportional to the operating time of the air pump 56. For this reason, in the present embodiment, the correction for increasing the supply amount of the secondary air corresponds to the correction for extending the secondary air supply time, that is, the operation time of the air pump 56.

[Specific Processing in Embodiment 4]
FIG. 11 and FIG. 12 are flowcharts of routines executed by the ECU 50 in the present embodiment in order to realize the above functions. These routines are executed every predetermined time. 11 and 12, the same steps as those shown in FIGS. 2 and 4 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  The routine shown in FIG. 11 is a routine for correcting the target supply time of secondary air in accordance with the vehicle altitude. In the ECU 50, a predetermined reference supply time is set in advance as a target supply time of the secondary air. The reference supply time is set to a time during which a sufficient secondary air supply amount necessary for effectively performing odor suppression control on a flat ground can be secured.

  According to the routine shown in FIG. 11, first, the atmospheric pressure KPA is acquired (step 100), and then it is determined whether or not the atmospheric pressure KPA is smaller than the high altitude determination value (step 102). As a result, when it is recognized that the atmospheric pressure KPA is equal to or higher than the highland determination value, it can be determined that the vehicle is on a flat ground. In this case, the correction of the target supply time of the secondary air is not performed, and the preset reference supply time becomes the target supply time as it is.

  On the other hand, if it is determined in step 102 that the atmospheric pressure KPA is smaller than the high altitude determination value, it can be determined that the vehicle is in the high altitude. In this case, next, a correction coefficient for extending the target supply time of the secondary air is calculated (step 144). The ECU 50 stores a map (not shown) in which the correction coefficient is determined in relation to the atmospheric pressure KPA. As this map, a map having the same tendency as the map shown in FIG. 3 is used. In step 144, a correction coefficient (> 1) is calculated by referring to the map. Then, a value obtained by multiplying the correction coefficient by the reference supply time is set as the target supply time of the secondary air (step 146).

  The routine shown in FIG. 12 is a routine for performing odor suppression control. According to the routine shown in FIG. 12, the same processing as the routine shown in FIG. 4 is performed until the processing of step 112 for determining whether or not the upstream catalyst 40 and the downstream catalyst 42 are at a high temperature. In the process up to step 112, when it can be determined that hydrogen sulfide is likely to be generated, odor suppression control is performed to suppress the catalyst exhaust odor. Specifically, secondary air is supplied by operating the air pump 56 for the target supply time (step 148). In this case, the supply time of the secondary air is corrected so as to become longer according to the vehicle altitude by the routine processing shown in FIG. 11 described above. Therefore, even in a high altitude where oxygen is lean, an amount of oxygen that can sufficiently oxidize the entire upstream catalyst 40 and downstream catalyst 42 is supplied, so that generation of catalyst exhaust odor can be reliably suppressed. it can.

  In the fourth embodiment described above, the secondary air supply amount is the “control parameter” in the first invention, and the direction in which the secondary air supply amount is increased is the “increase direction in the first invention”. Respectively. Further, the ECU 50 executes the processing of the above steps 144, 146 and 148, thereby realizing the “parameter correcting means” in the first invention.

  Further, the secondary air supply process peculiar to the fourth embodiment may be performed in combination with the first to third embodiments.

Embodiment 5. FIG.
[Features of Embodiment 5]
Next, a fifth embodiment of the present invention will be described with reference to FIG. 13. The description will focus on the differences from the above-described embodiments, and the description of similar matters will be omitted or simplified. . The system of the present embodiment can be realized by causing the ECU 50 to execute a routine shown in FIG. 13 described later using the hardware configuration shown in FIG.

  In the fourth embodiment described above, when the odor suppression control is performed during the deceleration fuel cut, the throttle valve 18 is not opened, and much of the air for oxidizing the upstream catalyst 40 and the downstream catalyst 42 is increased to the vehicle altitude. Regardless, it is supposed to be served by secondary air. On the other hand, in the present embodiment, when performing odor suppression control, the upstream catalyst 40 and the downstream catalyst 42 are oxidized by opening the throttle valve 18 on the flat ground without supplying the secondary air. Secure the air. In the highlands, secondary air is supplied in addition to opening of the throttle valve 18, and the effect of oxygen dilution is offset by the added secondary air.

[Specific Processing in Embodiment 5]
FIG. 13 is a flowchart of a routine executed by the ECU 50 in the present embodiment in order to realize the above function. This routine is executed every predetermined time. In FIG. 13, the same steps as those shown in FIGS. 2 and 4 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  According to the routine shown in FIG. 13, during the deceleration fuel cut, the same processing as the routine shown in FIG. 4 is performed until the processing of step 112 for determining whether or not the upstream catalyst 40 and the downstream catalyst 42 are hot. If it can be determined in the processing up to step 112 that hydrogen sulfide is likely to be generated, the throttle valve 18 is then turned on to oxidize the upstream catalyst 40 and the downstream catalyst 42 to suppress the generation of hydrogen sulfide. Odor suppression control that opens to the reference opening at the time of odor suppression is performed (step 150).

  Next, according to the routine shown in FIG. 13, the atmospheric pressure KPA is acquired (step 100), and it is further determined whether or not the atmospheric pressure KPA is smaller than the high altitude determination value (step 102).

  If it is determined in step 102 that the atmospheric pressure KPA is smaller than the high altitude determination value, it can be determined that the vehicle is in the high altitude. In this case, the secondary pump is supplied by operating the air pump 56 for a predetermined time (step 152). As a result, the influence of oxygen dilution at high altitudes is offset, so that a sufficient catalyst exhaust odor suppression effect can be obtained.

  On the other hand, when it is recognized in step 102 that the atmospheric pressure KPA is equal to or higher than the highland determination value, it can be determined that the vehicle is on a flat ground. In this case, since the amount of air supplied through the throttle valve 18 is sufficient, the secondary air is not supplied.

  In the fifth embodiment described above, the secondary air supply amount is the “control parameter” in the first invention, and the direction in which the secondary air supply amount is increased is the “increase direction in the first invention”. Respectively. Further, the “parameter correcting means” according to the first aspect of the present invention is realized by the ECU 50 executing the processing of step 152 described above.

  In addition, the secondary air supply process peculiar to the fifth embodiment described above may be performed in combination with the first to third embodiments.

It is a figure for demonstrating the system configuration | structure of Embodiment 1 of this invention. It is a flowchart of the routine performed in Embodiment 1 of the present invention. It is a figure which shows the map referred in order to obtain | require a correction coefficient in the routine shown in FIG. It is a flowchart of the routine performed in Embodiment 1 of the present invention. It is a figure which shows the map referred in order to obtain | require target throttle opening in the routine shown in FIG. It is a flowchart of the routine performed in Embodiment 2 of this invention. It is a flowchart of the routine performed in Embodiment 3 of the present invention. It is a figure which shows the map referred in order to obtain | require the start delay time of the deceleration fuel cut in the routine shown in FIG. It is a figure which shows the map referred in order to obtain | require a fuel cut return rotation speed in the routine shown in FIG. It is a figure for demonstrating the system configuration | structure of Embodiment 4 of this invention. It is a flowchart of the routine performed in Embodiment 4 of this invention. It is a flowchart of the routine performed in Embodiment 4 of this invention. It is a flowchart of the routine performed in Embodiment 5 of this invention.

Explanation of symbols

Reference Signs List 10 internal combustion engine 12 intake passage 14 exhaust passage 18 throttle valve 20 throttle motor 22 throttle position sensor 24 accelerator position sensor 26 fuel injection valve 40 upstream catalyst 42 downstream catalyst 44 air-fuel ratio sensor 46 oxygen sensor 47, 48 temperature sensor 49 atmospheric pressure sensor 50 ECU
56 Air Pump 66 VSV

Claims (8)

A catalyst provided in an exhaust passage of an internal combustion engine mounted on a vehicle and purifying exhaust gas;
An altitude index detecting means for detecting a vehicle altitude or an index correlated with the vehicle altitude;
Parameter correction means for performing correction control for correcting a control parameter related to the total amount of oxygen supplied to the catalyst during deceleration of the internal combustion engine in a direction to increase the total amount as the vehicle altitude increases.
A control device for an internal combustion engine, comprising: High altitude determination means for performing high altitude determination based on the detection value of the altitude index detection means,
The control apparatus for an internal combustion engine according to claim 1, wherein the parameter correction means performs the correction control when the highland determination is affirmed.   3. The control apparatus for an internal combustion engine according to claim 1, wherein the parameter correction means includes means for performing the correction control so that the control parameter continuously changes in accordance with a vehicle altitude. Fuel cut means for performing fuel cut during the deceleration,
The control parameter is a throttle opening during fuel cut,
4. The control apparatus for an internal combustion engine according to claim 1, wherein the increasing direction is a direction in which the throttle opening is increased. An accelerator position sensor that detects that the accelerator pedal has been depressed;
And a throttle return means for reducing the throttle opening when it is detected that the accelerator pedal is depressed when the parameter correction means is corrected to increase the throttle opening. The control apparatus for an internal combustion engine according to claim 4. Fuel cut means for performing fuel cut during the deceleration,
The control parameter is a start delay time from when the fuel cut execution condition is satisfied to when the fuel cut is started,
6. The control device for an internal combustion engine according to claim 1, wherein the increasing direction is a direction for shortening the start delay time. Fuel cut means for performing fuel cut during the deceleration,
The control parameter is a fuel cut return rotational speed,
7. The control device for an internal combustion engine according to claim 1, wherein the increasing direction is a direction in which the fuel cut return rotational speed is decreased. A secondary air supply means for supplying secondary air to the catalyst during the deceleration;
The control parameter is a supply amount of the secondary air,
8. The control device for an internal combustion engine according to claim 1, wherein the increasing direction is a direction in which the supply amount of the secondary air is increased.

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