JP5678427B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a control device for a vehicle that transmits a driving force of an internal combustion engine to driving wheels via an automatic transmission and that performs blipping control during a downshift during deceleration fuel cut.

  In an automatic transmission mounted on a vehicle, the power transmission path of the transmission gear mechanism is switched to switch to a plurality of gear stages having different gear stages. Further, in a vehicle equipped with such an automatic transmission, there is a transmission loss in the torque converter, so that deterioration of fuel consumption is unavoidable as compared with, for example, a vehicle equipped with a manual transmission. Therefore, a clutch that mechanically connects the output shaft of the internal combustion engine and the input shaft of the automatic transmission without using a torque converter, that is, a lock-up mechanism is provided, and the mechanism functions appropriately at all speed stages as well as at high speed stages. Vehicles that perform so-called full lockup have been put to practical use. There has also been proposed a vehicle that includes a mechanical clutch that is automatically driven instead of the torque converter, and that automatically connects and disconnects the output shaft of the internal combustion engine and the input shaft of the automatic transmission. Yes. In such a vehicle, since the output shaft of the internal combustion engine and the input shaft of the automatic transmission can be mechanically connected by engaging the clutch, the transmission loss as described above does not occur and the fuel consumption is improved. In addition, the engine braking performance equivalent to that of a vehicle equipped with a manual transmission can be obtained by connecting and disconnecting the clutch at the time of downshift.

  Many of these vehicles have a function of allowing the driver to arbitrarily switch the gear position of the automatic transmission, that is, a so-called manual shift select function. In a vehicle having this function, by operating a shift lever provided on the floor, a paddle type shift switch provided on the back of the steering wheel, or a push-type shift switch provided on the spoke of the wheel. Since the shift stage of the automatic transmission can be easily changed, it is possible to obtain a flexible vehicle travel characteristic in accordance with the driver's intention.

  By the way, in such an automatic transmission of a vehicle, when a downshift is performed through a manual shift select function, a mechanical clutch such as a lockup mechanism as described above is automatically released after being released from an engaged state. The power transmission path of the transmission gear mechanism in the transmission is switched. When the clutch is thus released and the gear position is switched, the rotational speed of the input shaft of the automatic transmission temporarily rises higher than the rotational speed of the output shaft of the internal combustion engine, resulting in a rotational speed difference therebetween. . When the clutch is re-engaged under such circumstances, a large shift shock is generated accordingly.

  Therefore, conventionally, as described in Patent Document 1, for example, when such a downshift is performed, the throttle valve is opened to increase the intake air amount, and the fuel injection amount is temporarily increased, or If the fuel cut during deceleration is in progress, the fuel injection is temporarily resumed, for example, to increase the engine rotation speed, that is, by performing blipping control, the output shaft of the internal combustion engine and the input of the automatic transmission An apparatus has been proposed in which the difference in rotational speed from the shaft is reduced to mitigate shift shock during downshifting.

JP 2008-256189 A

  In a vehicle as described above, for example, a vehicle is equipped with a manual transmission while suppressing a shift shock by repeating a downshift in a short period of time when the vehicle decelerates and executing a blipping control accordingly. Stable braking by engine braking can be performed.

However, if downshifts are frequently performed in such a short period of time, and blipping control is performed each time, there is a concern about the following inconveniences.
That is, since the exhaust purification catalyst provided in the exhaust passage has a function of storing oxygen in the carrier, the amount of oxygen stored in the carrier increases during a fuel cut such as during vehicle deceleration. It becomes like this. When a part of the fuel injected by the execution of the blipping control is discharged to the exhaust system without being used for combustion, it reacts with the oxygen stored in the carrier of the exhaust purification catalyst and burns. The temperature of the catalyst (catalyst bed temperature) may increase excessively. If the catalyst bed temperature rises excessively in an oxygen-rich atmosphere, the precious metal such as platinum, which is an activation material for the exhaust purification catalyst, aggregates and enlarges so-called sintering. As a result, the function of the exhaust purification catalyst is reduced. In particular, in the blipping control, the ignition timing is retarded in order to suppress the occurrence of knocking and the torque of the internal combustion engine from being increased more than necessary, and the exhaust temperature rise associated with such retarding of the ignition timing is suppressed. In many cases, the fuel injection amount is corrected to be increased for the purpose. If the fuel injection amount is corrected to increase in this way, the rise in the exhaust temperature can be suppressed, but the unburned components of the fuel combusted in the exhaust purification catalyst will increase, thus further promoting the temperature rise in the catalyst bed temperature. Will end up.

  An object of the present invention is to provide a vehicle control device that can make it difficult for a situation in which the catalyst bed temperature rises excessively when deceleration fuel cut is being performed.

  [1] According to one aspect of the vehicle control apparatus of the present invention, an internal combustion engine having an output shaft and an exhaust passage, a stepped automatic transmission having an input shaft, and connecting or disconnecting the output shaft and the input shaft And a control device for a vehicle including a mechanical clutch that cuts the output shaft and the input shaft when the automatic transmission downshifts, and an exhaust purification catalyst disposed in the exhaust passage, When the vehicle is decelerating, performing a decelerating fuel cut to stop fuel injection of the internal combustion engine, executing the decelerating fuel cut, and when the automatic transmission downshifts; and When the catalyst bed temperature, which is the temperature of the exhaust purification catalyst, is equal to or lower than the determination temperature, the blipping control for injecting the fuel to the internal combustion engine is executed. Basic fuel that is the amount of fuel that is injected into the internal combustion engine so that the difference between the rotational speed of the output shaft of the internal combustion engine and the rotational speed of the input shaft of the automatic transmission that is generated by downshifting the transmission is reduced. In accordance with the basic fuel injection amount, the injection amount is set and retarded from the ignition timing of the internal combustion engine that matches the basic fuel injection amount that has not been corrected for increase, so that the occurrence of knocking or shock is suppressed. The ignition timing retard amount is set, a correction amount for increasing the basic fuel injection amount according to the ignition timing retard amount is set, and the basic fuel injection is increased by the correction amount. When the fuel is injected into the internal combustion engine based on the amount and the deceleration fuel cut is performed, and when the automatic transmission is downshifted, and the catalyst bed temperature is equal to the determination temperature. Is higher, the blipping control is not executed, or the deceleration fuel cut is executed, and the automatic transmission is downshifted, and the catalyst bed temperature is higher than the determination temperature. The blipping control is executed, and less fuel is injected into the internal combustion engine than the fuel injected into the internal combustion engine by the blipping control executed when the catalyst bed temperature is equal to or lower than the determination temperature.
  [2] According to an example of the control device for the vehicle, when the catalyst bed temperature is higher than the determination temperature, the amount of intake air of the internal combustion engine when the blipping control is not executed is expressed as the catalyst bed temperature. When the temperature is equal to or lower than the determination temperature, the amount of intake air of the internal combustion engine when the blipping control is executed is increased, or when the catalyst bed temperature is higher than the determination temperature, the catalyst bed temperature is The intake air amount of the internal combustion engine is increased more than when the temperature is lower than the determination temperature, the blipping control is executed, and the internal combustion engine is injected by the blipping control executed when the catalyst bed temperature is lower than the determination temperature. Less fuel than the fuel to be injected is injected into the internal combustion engine.
  [3] According to one aspect of the vehicle control apparatus of the present invention, an internal combustion engine having an output shaft and an exhaust passage, a stepped automatic transmission having an input shaft, and connecting or disconnecting the output shaft and the input shaft And a control device for a vehicle including a mechanical clutch that cuts the output shaft and the input shaft when the automatic transmission downshifts, and an exhaust purification catalyst disposed in the exhaust passage, When the vehicle is decelerating, performing a decelerating fuel cut to stop fuel injection of the internal combustion engine, executing the decelerating fuel cut, and when the automatic transmission downshifts; and A blippin for injecting fuel to the internal combustion engine when the exhaust purification function of the exhaust purification catalyst is not suggested by the catalyst bed temperature which is the temperature of the exhaust purification catalyst Control, and in the blipping control, the difference between the rotation speed of the output shaft of the internal combustion engine and the rotation speed of the input shaft of the automatic transmission is reduced by the downshift of the automatic transmission. A basic fuel injection amount, which is the amount of fuel injected into the internal combustion engine, is set and retarded from the ignition timing of the internal combustion engine that matches the basic fuel injection amount that is not corrected for increase, and knocking or shock is generated. A retard amount of the ignition timing is set according to the basic fuel injection amount so as to be suppressed, and a correction amount for increasing the basic fuel injection amount according to the retard amount of the ignition timing is set. When the fuel is injected into the internal combustion engine based on the basic fuel injection amount that has been increased by the correction amount and the deceleration fuel cut is being performed, and the automatic transmission is When shifting, and when the catalyst bed temperature suggests that the exhaust purification function of the exhaust purification catalyst is reduced, when the blipping control is not executed, or when the deceleration fuel cut is executed And when the automatic transmission downshifts and when the catalyst bed temperature indicates that the exhaust purification function of the exhaust purification catalyst is degraded, the blipping control is executed, and so on. Less fuel than the fuel injected into the internal combustion engine is injected into the internal combustion engine by the blipping control executed when not suggested.
  [4] According to an example of the vehicle control device, the internal combustion engine when the blipping control is not executed when the catalyst bed temperature indicates that the exhaust purification function of the exhaust purification catalyst is deteriorated. The intake air amount of the internal combustion engine is increased when the blipping control is executed when it is not so suggested, or the exhaust purification function of the exhaust purification catalyst is reduced. Is suggested by the catalyst bed temperature, the intake air amount of the internal combustion engine is increased more than when not so suggested, and the blipping control is executed, and when not so suggested Less fuel than the fuel injected into the internal combustion engine is injected into the internal combustion engine by the blipping control to be executed.
  [5] According to one aspect of the vehicle control device of the present invention, an internal combustion engine having an output shaft and an exhaust passage, a stepped automatic transmission having an input shaft, and connecting or disconnecting the output shaft and the input shaft And a control device for a vehicle including a mechanical clutch that cuts the output shaft and the input shaft when the automatic transmission downshifts, and an exhaust purification catalyst disposed in the exhaust passage, When the vehicle is decelerating, performing a decelerating fuel cut to stop fuel injection of the internal combustion engine, executing the decelerating fuel cut, and when the automatic transmission downshifts; and When the catalyst bed temperature, which is the temperature of the exhaust purification catalyst, is equal to or lower than the first determination temperature, the blipping control for injecting fuel to the internal combustion engine is executed. Basic amount of fuel that is injected into the internal combustion engine so that the difference between the rotational speed of the output shaft of the internal combustion engine and the rotational speed of the input shaft of the automatic transmission that is generated by downshifting the automatic transmission is reduced. A fuel injection amount is set, and the basic fuel injection amount is set so as to be retarded from the ignition timing of the internal combustion engine that matches the basic fuel injection amount that has not been corrected for increase and the occurrence of knocking or shock is suppressed. The ignition timing retard amount is set according to the ignition timing retard amount, the correction amount for increasing the basic fuel injection amount according to the ignition timing retard amount is set, and the basic fuel that is increased by the correction amount is corrected. The fuel is injected into the internal combustion engine based on the injection amount, the deceleration fuel cut is executed, the automatic transmission is downshifted, and the catalyst bed temperature is the first level. The blipping control is executed when the temperature is lower than the second determination temperature that is higher than the temperature and higher than the first determination temperature, and is executed when the catalyst bed temperature is lower than the first determination temperature. Less fuel than that injected into the internal combustion engine by blipping control is injected into the internal combustion engine, the deceleration fuel cut is executed, and the automatic transmission downshifts, and the catalyst When the bed temperature is higher than the second determination temperature, the blipping control is not executed, the deceleration fuel cut is executed, and the automatic transmission is downshifted, and the catalyst When the bed temperature is higher than the second determination temperature, the blipping control is executed, and when the catalyst bed temperature is higher than the first determination temperature and equal to or lower than the second determination temperature. Less fuel than the fuel injected into the internal combustion engine is injected into the internal combustion engine by the blipping control to be executed.
  [6] According to one aspect of the vehicle control device of the present invention, an internal combustion engine having an output shaft and an exhaust passage, a stepped automatic transmission having an input shaft, and connecting or disconnecting the output shaft and the input shaft And a control device for a vehicle including a mechanical clutch that cuts the output shaft and the input shaft when the automatic transmission downshifts, and an exhaust purification catalyst disposed in the exhaust passage, When the vehicle is decelerating, performing a decelerating fuel cut to stop fuel injection of the internal combustion engine, executing the decelerating fuel cut, and when the automatic transmission downshifts; and Based on the relationship between the catalyst bed temperature, which is the temperature of the exhaust purification catalyst, and the first judgment temperature, the second judgment that the catalyst bed temperature is higher than the first judgment temperature due to fluctuations in the catalyst bed temperature. The internal combustion engine is caused by down-shifting the automatic transmission in the blipping control when the internal combustion engine is not suggested to be likely to reach The basic fuel injection amount, which is the amount of fuel to be injected into the internal combustion engine, is set so that the difference between the rotation speed of the output shaft and the rotation speed of the input shaft of the automatic transmission is reduced, and the increase correction is not performed The retard amount of the ignition timing is set according to the basic fuel injection amount so that the ignition timing of the internal combustion engine that matches the basic fuel injection amount is retarded and the occurrence of knocking or shock is suppressed. A correction amount for increasing the basic fuel injection amount according to the retard amount of the ignition timing is set, and based on the basic fuel injection amount corrected by increasing the correction amount, When the fuel is injected into the internal combustion engine and the deceleration fuel cut is executed, and when the automatic transmission is downshifted, and the catalyst bed temperature is changed by the fluctuation of the catalyst bed temperature, the catalyst bed temperature becomes the second determination temperature. The blipping control is executed when the relationship between the catalyst bed temperature and the first determination temperature is suggested to be high, and the blipping control is executed when it is not so suggested Less fuel than the fuel to be injected into the internal combustion engine by control is injected into the internal combustion engine to perform the deceleration fuel cut, and when the automatic transmission is downshifted, and the exhaust purification catalyst When the relationship between the catalyst bed temperature and the second determination temperature suggests that the exhaust gas purification function is reduced, the blipping control is not executed, or the previous When the deceleration fuel cut is executed, the automatic transmission is downshifted, and the exhaust purification function of the exhaust purification catalyst is reduced, the catalyst bed temperature and the second determination temperature The blipping control is performed when suggested by a relationship, and the internal combustion engine is injected with less fuel than the fuel that is injected into the internal combustion engine by the blipping control that is performed when not implied. .
  [7] According to an example of the vehicle control device, the automatic fuel reduction is performed when the deceleration fuel cut is performed, and when the automatic transmission is downshifted, the deceleration fuel cut is performed. The intake air amount of the internal combustion engine is increased more than before the transmission is downshifted, and the air-fuel ratio or the stoichiometric air-fuel ratio on the richer side than the stoichiometric air-fuel ratio is set based on the increased intake air amount of the internal combustion engine. The basic fuel injection amount is set based on the air-fuel ratio.

The vehicle control device according to [1] to [7] has the following effects.
The blipping control has a risk of causing knocking and a risk of generating a shock due to an increase in torque. Knocking or shock is less likely to occur when the ignition timing is retarded than when the ignition timing is not retarded. For this reason, the control device can make it difficult to cause knocking or shock by retarding the ignition timing of the internal combustion engine when the basic fuel injection amount for blipping control is set . On the other hand, the exhaust temperature is likely to rise as the ignition timing is retarded.
When the ignition timing of the internal combustion engine is retarded according to the basic fuel injection amount , the control device increases the fuel injection amount according to the retard amount of the ignition timing. For this reason, it becomes difficult for the exhaust temperature to rise. On the other hand, when the ignition timing of the internal combustion engine is retarded according to the basic fuel injection amount, the fuel discharged to the exhaust system tends to increase. For this reason, the fuel combusted in the exhaust purification catalyst tends to increase. For this reason, the catalyst bed temperature is likely to rise.
The control device changes the fuel injection mode of the internal combustion engine in accordance with the catalyst bed temperature when executing the deceleration fuel cut and when the automatic transmission downshifts . For this reason, it is possible to select a fuel injection mode that makes it difficult for the catalyst bed temperature to rise. For this reason, the situation where the catalyst bed temperature rises excessively can be made difficult to occur. For this reason, the sintering of the exhaust purification catalyst is less likely to occur. For this reason, the exhaust purification function of the exhaust purification catalyst is unlikely to deteriorate .
In one form of control, the control device does not perform blipping control. For this reason, it is difficult for unburned components to be discharged into the exhaust system. For this reason, compared with the case where blipping control is performed , a catalyst bed temperature becomes difficult to raise.
In another form of control, the control device executes blipping control and reduces the fuel injection amount of the internal combustion engine in the blipping control. For this reason, compared with the case where blipping control is not performed , an engine speed increases. For this reason, the shift shock is easily reduced. The unburned component is less likely to be discharged into the exhaust system as compared with the case where the fuel injection amount of the internal combustion engine in the blipping control is not reduced. For this reason, it becomes difficult for the catalyst bed temperature to rise.
The vehicle control device according to [2] or [4] has the following effects.
The control device increases the intake air amount of the internal combustion engine as described in [2] or [4] . For this reason, the amount of air flowing into the exhaust purification catalyst increases. For this reason, the exhaust purification catalyst is easily cooled by air. For this reason, the catalyst bed temperature tends to decrease.

The schematic diagram which shows the vehicle-mounted internal combustion engine and automatic transmission of 1st Embodiment , and those periphery structures. The flowchart which shows the process sequence about the vehicle control at the time of the deceleration concerning 1st Embodiment. The graph which shows the relationship between the amount of intake air, and the fall rate of a catalyst bed temperature. The graph which shows the relationship between the total fuel increase amount and the increase amount of a catalyst bed temperature. The timing chart which shows the operation example of the vehicle control at the time of the deceleration of 1st Embodiment. The flowchart which shows the process sequence about the vehicle control at the time of the deceleration of 2nd Embodiment . The flowchart which shows the process sequence about the vehicle control at the time of the deceleration of 3rd Embodiment . The timing chart which shows the operation example of the vehicle control at the time of the deceleration of 3rd Embodiment.

(First embodiment)
The first embodiment will be described with reference to FIGS.
FIG. 1 shows a control device according to this embodiment and a vehicle V to which the control device is applied. As shown in FIG. 1, the vehicle V is mounted with a six-speed automatic transmission 40 including a torque converter 41 and a transmission gear mechanism 42 in addition to the internal combustion engine 10. The driving force of the internal combustion engine 10 is transmitted to the driving wheels 46 through the driving system of the vehicle V such as the automatic transmission 40. An intake passage 21 and an exhaust passage 31 are connected to a combustion chamber (not shown) of the internal combustion engine 10. The intake passage 21 is provided with a throttle valve 22 for adjusting the amount of intake air in accordance with the opening (throttle opening TA), while the exhaust passage 31 is provided with an exhaust purification catalyst 32 for purifying exhaust. ing. The internal combustion engine 10 and the automatic transmission 40 are controlled in an integrated manner by an electronic control unit 50.

  The automatic transmission 40 is provided with a lock-up mechanism 45 having a friction clutch that mechanically connects and disconnects the input shaft (input shaft 43) and the output shaft 11 of the internal combustion engine 10. In addition to the friction clutch, the lock-up mechanism 45 includes a hydraulic system (not shown) that switches the clutch between an engaged state and a released state by hydraulic pressure. This hydraulic system is provided with a control valve for switching the engagement / release state of the friction clutch. This control valve is controlled to open and close by the electronic control unit 50. When the lockup mechanism 45 is engaged, the driving force of the internal combustion engine 10 is directly transmitted from the output shaft 11 to the input shaft 43 of the automatic transmission 40 without passing through the torque converter 41, and from the input shaft 43. It is transmitted to the transmission gear mechanism 42. In the present embodiment, the lock-up mechanism 45 is a so-called full lock-up mechanism that operates any shift speed from 1st to 6th as long as the lock-up execution condition is satisfied. Is adopted.

  In the automatic transmission 40, the shift stage is switched in two forms: an auto shift select mode (A mode) and a manual shift select mode (M mode). Here, in the A mode, basically, the gear position is automatically changed based on the vehicle speed and the operation amount of the accelerator pedal 1 (accelerator opening ACCP). On the other hand, in the M mode, the driver operates the shift lever provided on the floor of the vehicle V and the paddle type shift switch provided on the back of the steering wheel (both not shown), so that the automatic transmission 40 The command gear stage is set, and the transmission gear mechanism 42 is controlled so as to be the command gear stage. That is, the gear position is arbitrarily changed in accordance with the driver's intention. For example, when the vehicle is decelerated, the shift lever or the shift switch is operated to shift the automatic transmission 40 to the M mode, the lockup mechanism 45 is released, the shift gear mechanism 42 is used to change the shift stage to a low speed stage, and the change It is possible to obtain engine braking performance similar to that of a vehicle equipped with a manual transmission by repeating a series of downshift processes such as quickly bringing the lockup mechanism 45 into an engaged state later in a short period of time. become.

  By the way, when the vehicle is decelerated while the shift lever or the shift switch is not operated and the automatic transmission 40 is in the A mode, the speed change is not performed until the engine speed reaches the lower limit speed that does not cause a stall. . That is, the speed stage is maintained at, for example, 6th speed until the engine rotational speed reaches the lower limit rotational speed, and the speed stage is changed from 6th speed to 5th speed only when the engine rotational speed becomes the lower limit rotational speed. Later, the shift control is executed such that the gear position is changed from the 5th speed to the 4th speed when the engine speed is again lowered to the lower limit speed. By controlling the gear position of the automatic transmission 40 in this way, fuel cut over a long period can be executed during vehicle deceleration, and fuel consumption can be improved.

  The electronic control unit 50 includes an accelerator position sensor 51 that detects the accelerator opening ACCP, an air flow meter 52 that detects the intake air amount GA, and the rotational speed (input rotation) of the input shaft 43 of the automatic transmission 40 (transmission gear mechanism 42). The input rotational speed sensor 53 for detecting the speed NT), the output rotational speed sensor 54 for detecting the rotational speed of the output shaft 44 used for calculating the vehicle speed, and the shift for outputting signals based on the operation of the shift lever and the shift switch. Various sensors such as sensors 55 and 56 and a rotational speed sensor 57 for detecting the engine rotational speed NE are connected. The electronic control device 50 appropriately takes in the detection signals of these sensors, thereby controlling the internal combustion engine 10 such as throttle opening TA, fuel injection amount, ignition timing, fuel cut during deceleration, and engagement of the lockup mechanism 45. The control relating to the automatic transmission 40 such as switching of the release state and switching of the gear position by the transmission gear mechanism 42 is executed.

  By the way, as described above, a shift shock occurs when the lockup mechanism 45 is engaged when the input rotational speed NT is significantly higher than the engine rotational speed NE during downshifting during deceleration fuel cut. There is a fear. For this reason, the electronic control unit 50 performs blipping control to suppress this. That is, when the shift lever or the shift switch is operated, the electronic control unit 50 releases the lockup mechanism 45, increases the throttle opening TA, and temporarily restarts fuel injection. Then, the electronic control device 50 changes the gear position of the transmission gear mechanism 42 to the low speed gear in conjunction with the execution of the blipping control, and immediately after that change causes the lockup mechanism 45 to shift to the engaged state. Here, when the shift down and the accompanying blipping control are frequently repeated during a short time during the deceleration fuel cut, the catalyst bed temperature θ of the exhaust purification catalyst 32 may be excessively increased. As stated.

  Therefore, in the vehicle control apparatus according to the present embodiment, the catalyst bed temperature θ is monitored during the downshift during the deceleration fuel cut, and when the monitored catalyst bed temperature θ becomes relatively high, the increase is suppressed. Processing (suppression processing) is executed. Hereinafter, a series of processes related to vehicle control during deceleration fuel cut, particularly control of the internal combustion engine 10, including this suppression process, will be described with reference to FIG. This series of processing is repeatedly executed by the electronic control unit 50 with a predetermined calculation cycle Δt during engine operation.

  First, in step S110, it is determined whether or not a fuel cut is in progress. If it is determined that the fuel is not being cut, in step S200, the catalyst bed temperature θ is calculated based on the engine operating state at that time, specifically, the engine speed NE and the accelerator opening ACCP, and this processing is performed. Is terminated. The memory of the electronic control unit 50 indicates the relationship between the steady-state catalyst bed temperature, the engine speed NE, and the accelerator opening ACCP during steady operation, that is, when the engine speed NE and the accelerator opening ACCP are held constant. The calculation map shown is stored. The electronic control unit 50 refers to this calculation map to obtain the steady-state catalyst bed temperature corresponding to the engine rotational speed NE and the accelerator opening ACCP at that time, and calculates the catalyst bed temperature θ by gradually changing them. calculate.

  On the other hand, when it is determined that the fuel is being cut, it is determined in step S120 whether or not it is a downshift timing, that is, in the period from the previous calculation cycle t (i-1) to the current calculation cycle t (i). It is determined whether or not the instructed shift stage of the automatic transmission 40 set based on the detection signals of the shift sensors 55 and 56 has been changed from the high speed stage side to the low speed stage side.

  If it is determined that it is not the town shift timing, the rate of decrease θ ′ of the catalyst bed temperature θ is calculated based on the intake air amount GA in step S210. In the memory of the electronic control unit 50, the relationship between the rate of decrease θ ′ of the catalyst bed temperature θ and the intake air amount GA is stored as a calculation map. FIG. 3 is a graph showing the above relationship in this calculation map. When the intake air amount GA is large, the effect of cooling the exhaust purification catalyst 32 by the intake air is increased. Therefore, as the intake air amount GA is larger, as shown in FIG. 'Is calculated as a large value.

  In step S220, the rate of decrease θ ′ is multiplied by the calculation cycle Δt, and the multiplied value (θ ′ · Δt) is subtracted from the catalyst bed temperature θ in the previous calculation cycle, which is the current calculation cycle. A new catalyst bed temperature θ is set.

  On the other hand, when it is determined in step S110 that the fuel cut is in progress and it is determined in step S120 that it is the downshift timing, the basic fuel injection amount Q1 when the blipping control is executed is calculated in step S130. Is done. Here, the basic fuel injection amount Q1 is set to an amount that can reduce the rotational speed difference ΔN between the engine rotational speed NE and the input rotational speed NT during the downshift. Specifically, the electronic control unit 50 first calculates the rotational speed difference ΔN that occurs with the downshift based on the engine rotational speed NE immediately before the downshift, the change in the gear position associated with the downshift, the vehicle speed, and the like. . In order to reduce the rotational speed difference ΔN, the throttle valve 22 is controlled so that the throttle opening degree TA increases as the rotational speed difference ΔN increases. Then, the basic fuel injection amount Q1 is calculated so that the air-fuel ratio becomes, for example, the stoichiometric air-fuel ratio, based on the intake air amount GA increased by the change in the throttle opening TA. In this case, the target value of the air-fuel ratio is set to the stoichiometric air-fuel ratio as described above, and the target value of the air-fuel ratio is set in consideration of the fact that the amount of wall surface fuel adhesion increases with the restart of fuel injection from the fuel cut. It can also be set to a richer side than the theoretical air-fuel ratio. That is, when calculating the basic fuel injection amount Q1, the target air-fuel ratio is appropriately changed from the stoichiometric air-fuel ratio according to various situations although the stoichiometric air-fuel ratio is used as a reference.

  Further, when the fuel injection is executed based on the basic fuel injection amount Q1 calculated in this way, the above-described rotational speed difference ΔN can be reduced, but knocking occurs or the torque of the internal combustion engine 10 is reduced. It may rise more than necessary and increase the shock when restarting the fuel cut. Therefore, the electronic control unit 50 retards the ignition timing from the normal timing set based on the engine speed NE, the basic fuel injection amount Q1, and the like in order to suppress the occurrence of such knocking and shock. Further, the electronic control unit 50 also corrects the fuel injection amount to be increased in order to suppress an increase in the exhaust gas temperature associated with the retard of the ignition timing. In step S140 following step S130, a correction amount Q2 for performing such an increase correction is calculated based on the retard amount of the ignition timing and the like.

  Next, in step S150, the total fuel increase amount ΣQ2 is calculated based on the correction amount Q2 and the time during which fuel injection is performed in the blipping control, and the catalyst bed temperature θ based on the total fuel increase amount ΣQ2. The amount of increase Δθ is calculated. Even when the fuel injection is performed based only on the basic fuel injection amount Q1 without increasing the basic fuel injection amount Q1, the exhaust contains an unburned component of the fuel. By burning at 32, the catalyst bed temperature θ rises. However, since the basic fuel injection amount Q1 is basically an amount that is set so that the air-fuel ratio becomes the stoichiometric air-fuel ratio, there are few unburned components of the fuel contained in the exhaust gas. Therefore, even if the basic fuel injection amount Q1 changes, the accompanying change in the catalyst bed temperature θ is relatively small. On the other hand, since most of the correction amount Q2 for increasing the basic fuel injection amount Q1 is discharged to the exhaust passage 31 as an unburned component, the catalyst bed temperature θ increases as the correction amount Q2 increases. It will be. Therefore, in this embodiment, the increase amount Δθ of the catalyst bed temperature θ is calculated based on the total fuel increase amount ΣQ2 that is an integrated value of the correction amount Q2.

  The memory of the electronic control unit 50 stores the relationship between the increase amount Δθ of the catalyst bed temperature θ and the total fuel increase amount ΣQ2 as a calculation map. FIG. 4 is a graph showing the relationship in the calculation map. As the total fuel increase amount ΣQ2 increases, the amount of unburned components discharged to the exhaust passage 31 during the blipping control increases, and the catalyst bed temperature θ increases. Therefore, as shown in FIG. 4, as the total fuel increase amount ΣQ2 increases, the increase amount Δθ of the catalyst bed temperature θ increases.

  In step S160, the amount of increase Δθ is added to the previous calculation cycle, that is, the catalyst bed temperature θ calculated immediately before the downshift timing, and the added value is set as the catalyst bed temperature θ in the current calculation cycle. The That is, the catalyst bed temperature θ when the fuel injection of the blipping control is executed is estimated before the fuel injection is executed.

  Next, in step S170, it is determined whether the catalyst bed temperature θ is higher than the determination temperature θK. Here, the determination temperature θK is stored in the memory of the electronic control unit 50 in advance through a test or the like as a temperature at which the above-described sintering occurs in the exhaust purification catalyst 32, that is, a temperature at which the exhaust purification function decreases. ing. When it is determined in step S170 that the catalyst bed temperature θ is equal to or lower than the determination temperature θK, it is determined that the catalyst bed temperature θ does not reach the determination temperature θK even if the blipping control is executed, and the process proceeds to step S190. The blipping control is executed.

  On the other hand, when it is determined in step S170 that the catalyst bed temperature θ is higher than the determination temperature θK, blipping control is prohibited in step S180, and fuel cut is continuously performed. By prohibiting the blipping control in this way, it is possible to suppress the catalyst bed temperature θ from becoming higher than the determination temperature θK and the exhaust purification function of the exhaust purification catalyst 32 from being deteriorated. In step S180, fuel injection associated with the blipping control is prohibited. Therefore, the amount of increase Δθ added when estimating the catalyst bed temperature θ in step S160 is subtracted from the catalyst bed temperature θ to reduce the current catalyst bed. Reset as temperature θ.

Next, with reference to FIG. 5, an example of changes in the command shift speed, the fuel injection, the engine rotational speed NE, the catalyst bed temperature θ, and the like when the above-described series of processing is executed will be described.
When the downshift, that is, when the command shift speed is changed from the sixth speed to the fifth speed at the timing t1 shown in FIG. 5, the catalyst bed temperature θ when the blipping control is executed at the timing t1 is estimated. . And when this estimated catalyst bed temperature (theta) is below the determination temperature (theta) K, blipping control is performed. That is, the throttle opening degree TA is changed to the opening side from the current opening degree (for example, “fully closed”) according to the rotational speed difference ΔN between the engine rotational speed NE and the input rotational speed NT, and fuel injection is executed. Is done. As a result, the engine rotational speed NE increases and the rotational speed difference ΔN with respect to the input rotational speed NT decreases, so that it is possible to suppress the occurrence of a shift shock associated with the lock-up mechanism 45 being brought into the engaged state again. . When the blipping control is executed in this way, the unburned component of the fuel burns in the exhaust purification catalyst 32, so that the actual catalyst bed temperature (broken line in the figure) is estimated catalyst bed temperature θ. Gradually rises with a delay.

During the period from timing t1 to t2, the engine speed NE gradually decreases and the catalyst bed temperature θ also gradually decreases due to the fuel cut being executed.
At the timing t2 and the timing t3, the blipping control is executed in the same manner as the timing t1 described above during the downshift.

  Here, the catalyst bed temperature θ immediately before the blipping control is executed at the timing t3 is higher than the catalyst bed temperature θ immediately before the blipping control is executed at the timing t2. This is because the increase amount Δθ of the catalyst bed temperature θ accompanying the execution of the blipping control at the timing t2 is a decrease in the catalyst bed temperature θ due to the fuel cut being executed during the period of the timing t2 to t3. This is because it is larger than the amount. That is, blipping control associated with the downshift is executed at timing t3 before the catalyst bed temperature θ decreases to the same level as the catalyst bed temperature θ at timing t2. When the blipping control accompanying the downshift is repeatedly executed during a short period (timing t1, t2, t3), the catalyst bed temperature θ gradually increases. However, although the catalyst bed temperature θ gradually increases in this way, it does not exceed the determination temperature θK.

  On the other hand, at timing t4, when the downshift, that is, when the command shift speed is changed from the 3rd speed to the 2nd speed, the catalyst bed temperature θ when fuel injection associated with the blipping control is executed is similarly estimated, When it is determined that the estimated catalyst bed temperature θ is higher than the determination temperature θK, the blipping control is prohibited. As a result, the rotational force is transmitted from the transmission gear mechanism 42 to the output shaft 11 of the internal combustion engine 10 via the torque converter 41, and the engine rotational speed NE is gradually different from the case where the blipping control is executed. To rise. Further, since the blipping control is prohibited, the unburned components of the fuel are not discharged into the exhaust passage 31, so that the exhaust purification catalyst 32 is cooled by the intake air so that the catalyst bed temperature θ gradually decreases. become.

  If the blipping control is executed at timing t4, the actual catalyst bed temperature exceeds the determination temperature θK as shown by a two-dot chain line in FIG. Will be reduced.

  At time t5, when the accelerator pedal 1 is depressed, the fuel cut is interrupted, and the throttle opening TA is controlled based on the accelerator opening ACCP. Then, the fuel injection amount is set based on the intake air amount GA so that the air-fuel ratio becomes the stoichiometric air-fuel ratio. When the fuel injection amount is controlled so that the air-fuel ratio becomes the stoichiometric air-fuel ratio in this way, the oxygen storage amount in the exhaust purification catalyst 32 decreases compared to when the fuel is cut, so the catalyst bed temperature θ is excessively high. It will not rise.

According to this embodiment described above, the following effects can be obtained.
(1) Even when downshift is frequently performed during deceleration fuel cut, if it is estimated that the catalyst bed temperature θ exceeds the determination temperature θK by executing blipping control, the catalyst bed temperature θ increases. Since the blipping control is prohibited as a suppression process for suppressing the catalyst bed temperature, it is possible to suppress an excessive rise in the catalyst bed temperature θ due to the execution of the blipping control. As a result, the deterioration of the exhaust purification function caused by the occurrence of sintering in the exhaust purification catalyst 32 can be suitably avoided.

  (2) Of the fuel injected during blipping control, the unburned amount of fuel discharged to the exhaust passage 31 becomes richer as the correction amount Q2 for increasing the basic fuel injection amount Q1 increases. The amount of ingredients increases. In the present embodiment, the increase amount Δθ of the catalyst bed temperature θ when the blipping control is executed based on the integrated value of the correction amount Q2, that is, the total fuel increase amount ΣQ2, is calculated. The catalyst bed temperature θ after execution of control can be obtained more accurately.

  (3) The total fuel increase amount ΣQ2 is calculated on the basis of the correction amount Q2 for performing the increase correction while calculating the catalyst bed temperature θ immediately before the execution of the blipping control and the time for executing the fuel injection in the blipping control. Further, an increase amount Δθ of the catalyst bed temperature θ is calculated based on the total fuel increase amount ΣQ2. Then, the amount of increase Δθ is added to the catalyst bed temperature θ immediately before the execution of the blipping control, so that the catalyst bed temperature θ after the execution of the blipping control is estimated prior to the execution of the blipping control. . Accordingly, whether or not to execute the blipping control can be set based on the catalyst bed temperature θ after the execution of the blipping control, and it is possible to appropriately suppress the catalyst bed temperature θ from rising excessively. It becomes like this.

(Second Embodiment)
The second embodiment will be described with reference to FIG. The second embodiment will be described with a focus on differences from the first embodiment. Note that the description of the configuration common to the first embodiment is omitted.

  In the vehicle control apparatus according to the first embodiment, the catalyst bed temperature θ is monitored at the time of downshift during the deceleration fuel cut, and the blipping control is prohibited when the monitored catalyst bed temperature θ becomes higher than the determination temperature θK. I tried to do it. In contrast, in this embodiment, in addition to the first embodiment, a determination temperature θK2 lower than the determination temperature θK (θK1 in the present embodiment) is set, and the catalyst bed temperature θ is higher than the determination temperature θK2. In some cases, the fuel injection amount during blipping control is reduced. Hereinafter, such a series of processes will be described with reference to FIG.

  Further, this series of processes in the present embodiment is obtained by replacing the processes after step S170 in the same control (FIG. 2) of the previous first embodiment with the contents shown in FIG. This is the same as in the first embodiment.

  First, the catalyst bed temperature θ is calculated in step S160 of FIG. 2, and it is determined in step S310 of FIG. 6 in this embodiment whether or not the catalyst bed temperature θ is higher than the determination temperature θK1. When it is determined in step S310 that the catalyst bed temperature θ is higher than the determination temperature θK1, the blipping control is prohibited in step S320 and the present process is terminated as in the first embodiment. In step S320, since fuel injection accompanying the blipping control is prohibited, the amount of increase Δθ added when estimating the catalyst bed temperature θ in step S160 of FIG. 2 is subtracted from the catalyst bed temperature θ. Reset the current catalyst bed temperature θ.

  On the other hand, when it is determined in step S310 that the catalyst bed temperature θ is equal to or lower than the determination temperature θK1, it is determined in step S330 whether the catalyst bed temperature θ is higher than the determination temperature θK2. Here, the determination temperature θK2 is a temperature at which it is assumed that there is a high possibility that the catalyst bed temperature θ will reach the previous determination temperature θK1 due to fluctuations in the catalyst bed temperature θ, although the deterioration of the exhaust purification function can be almost ignored. These are preliminarily adapted and stored in the memory of the electronic control unit 50 through tests and the like.

  When it is determined in step S330 that the catalyst bed temperature θ is equal to or lower than the determination temperature θK2, the catalyst bed temperature θ is determined to be less than the determination temperature θK2 even if the blipping control is executed. Determination is made and blipping control is executed in step S350. On the other hand, when it is determined in step S330 that the catalyst bed temperature θ is higher than the determination temperature θK2, the degree of opening of the throttle opening TA toward the opening side is limited although blipping control is executed. The That is, the intake air amount GA resulting from the blipping control is limited, and accordingly, the basic fuel injection amount Q1 is also reduced as compared with the case of normal blipping control (step S340). Thus, by reducing the basic fuel injection amount Q1 during the blipping control, it is possible to secure the fuel injection opportunity by the blipping control while suppressing the increase in the catalyst bed temperature θ. In step S340, since the fuel injection amount at the time of blipping control is reduced, the catalyst bed temperature θ at this time is reset as follows. First, the amount of increase Δθ added when the catalyst bed temperature θ is estimated in step S160 in FIG. 2 is subtracted from the current catalyst bed temperature θ. Next, correction is performed by multiplying the total fuel increase amount ΣQ2 calculated in step S150 by a correction coefficient K (K <1), and the increase amount Δθ is calculated based on the corrected total fuel increase amount K · ΣQ2. calculate. Then, the current catalyst bed temperature θ is reset by adding the amount of increase Δθ to the catalyst bed temperature θ. The correction coefficient K is set according to the degree of reduction in the fuel injection amount during the blipping control in step S340.

  The transition of the engine speed NE and the catalyst bed temperature θ in the case where the above series of processes is executed is shown by a one-dot chain line in FIG. As shown in the figure, although not sufficient, by increasing the engine rotational speed NE, the rotational speed difference ΔN between the engine rotational speed NE and the input rotational speed NT decreases, and the catalyst bed temperature θ also increases. The excessive rise will be suppressed.

According to this embodiment described above, in addition to the effects (1) to (3) of the first embodiment, the following effects can be achieved.
(4) When it is determined that the catalyst bed temperature θ is equal to or lower than the determination temperature θK1 and higher than the determination temperature θK2, the basic fuel injection amount Q1 during the blipping control is decreased. As a result, the unburned component of the fuel discharged to the exhaust passage 31 can be reduced, and an excessive increase in the catalyst bed temperature θ due to the reaction of the unburned component on the exhaust purification catalyst 32 can be suppressed. It becomes like this. Further, unlike the case where the fuel injection is not executed at all by prohibiting the blipping control, the engine speed NE can be increased to reduce the speed difference ΔN between the engine speed NE and the input speed NT. Therefore, the effect of suppressing the shift shock can also be obtained. Therefore, it is possible to reduce the shift shock while suppressing an excessive increase in the catalyst bed temperature θ.

(Third embodiment)
A third embodiment will be described with reference to FIGS. 7 and 8. The third embodiment will be described with a focus on differences from the first embodiment. Note that the description of the configuration common to the first embodiment is omitted.

  In the vehicle control apparatus according to the first embodiment, the catalyst bed temperature θ is monitored, and the blipping control is prohibited when the monitored catalyst bed temperature θ becomes higher than the determination temperature θK during the downshift during the deceleration fuel cut. I tried to do it. On the other hand, in this embodiment, in addition to the first embodiment, when the catalyst bed temperature θ is higher than the determination temperature θK, in addition to prohibiting blipping control, the throttle opening degree TA is changed to the open side. Thus, the intake air amount GA is increased. Hereinafter, such a series of processes will be described with reference to FIG.

  Further, this series of processing in this embodiment is obtained by replacing the processing after step S170 and the processing after step S220 in FIG. 2 shown in the first embodiment with the contents shown in FIG. This process is the same as in the first embodiment.

  First, when it is determined in step S170 of FIG. 2 that the catalyst bed temperature θ is higher than the determination temperature θK, a period in which fuel injection by blipping control is not executed in step S410 of FIG. 7 in the present embodiment. That is, in order to increase the intake air amount GA during the deceleration fuel cut, the throttle opening degree TA is changed to the opening side from the current opening degree (for example, “fully closed”). Thereafter, in step S420, blipping control, specifically, fuel injection is prohibited. At this time, since the fuel injection accompanying the blipping control is prohibited, the increase amount Δθ added when the catalyst bed temperature θ is estimated in step S160 is subtracted from the catalyst bed temperature θ to obtain the current catalyst bed temperature. Reset as θ.

  On the other hand, when it is determined in step S170 that the catalyst bed temperature θ is equal to or lower than the determination temperature θK, blipping control is executed in step S190 as in the first embodiment. That is, the throttle opening degree TA is set according to the blipping control.

  Further, after the catalyst bed temperature θ when the fuel is being cut and not at the downshift timing is calculated in step S220 in FIG. 2, the catalyst bed temperature θ is determined as the determination temperature θS in step S430 in FIG. Or higher is determined. Here, the determination temperature θS is stored in the electronic control unit 50 as a value for determining whether or not the catalyst bed temperature θ has been cooled until the blipping control can be executed and is preliminarily adapted through a test or the like. ing. Needless to say, the determination temperature θS and the previous determination temperature θK have a magnitude relationship of (θK> θS). When it is determined in step S430 that the catalyst bed temperature θ is higher than the determination temperature θS, it is determined that the catalyst bed temperature θ is not sufficiently lowered, and the present process is terminated. On the other hand, when it is determined in step S430 that the catalyst bed temperature θ is equal to or lower than the determination temperature θS, it is determined that the catalyst bed temperature θ is lowered and the blipping control can be performed, and in step S440, the opening is performed. The throttle opening degree TA that has been changed to the side is changed to the closing side (for example, “fully closed”), and this process is terminated.

Next, with reference to FIG. 8, an example of changes in the command shift speed, the fuel injection, the engine rotational speed NE, the catalyst bed temperature θ, and the like when the above-described series of processing is executed will be described.
At the time of downshift during the fuel cut at the timing t11 and the timing t12 shown in FIG. 8, the blipping control is executed similarly to the timing t1 and the timing t2 of the first embodiment. At time t13, when the downshift, that is, when the command shift speed is changed from the fourth speed to the third speed, the catalyst bed temperature θ when the blipping control is executed at the timing t13 is calculated. When it is determined that the estimated catalyst bed temperature θ is higher than the determination temperature θK, the throttle opening degree TA is changed to the open side, and blipping control is prohibited. As a result, the exhaust purification catalyst 32 is cooled by the intake air, and the catalyst bed temperature θ rapidly decreases. Further, the rotational force is transmitted from the transmission gear mechanism 42 to the output shaft 11 of the internal combustion engine 10 via the torque converter 41, and the engine rotational speed NE gradually increases unlike the case where the blipping control is executed. To come.

  When downshifting, that is, when the command shift speed is changed from the third speed to the second speed at the timing t14, the catalyst bed temperature θ when the blipping control is executed at the timing t14 is estimated. And when this estimated catalyst bed temperature (theta) is below the determination temperature (theta) K, blipping control is performed. As a result, the engine speed NE increases, and the unburned components of the fuel are combusted in the exhaust purification catalyst 32, so that the actual catalyst bed temperature (broken line in the figure) becomes the estimated catalyst bed temperature θ. It gradually rises with a delay.

  If the throttle opening degree TA is not changed to the opening side at the timing t13 at the timing t13 and the timing t14, the catalyst bed temperature θ gradually decreases as shown by a two-dot chain line in FIG. It becomes like this. In this case, at the timing of the downshift during the next fuel cut, the catalyst bed temperature θ exceeds the determination temperature θK, so that the blipping control cannot be executed at the timing t14. On the other hand, in the present embodiment, when it is determined that the catalyst bed temperature θ is higher than the determination temperature θK, the throttle opening degree TA is changed to the open side. The pressure decreases until it falls below θS, and the blipping control is promptly executed at the time of downshift during the next fuel cut.

  When the accelerator pedal 1 is depressed at timing t15, the fuel cut is interrupted, and the throttle opening degree TA is controlled based on the accelerator opening degree ACCP. Then, the fuel injection amount is set based on the intake air amount GA so that the air-fuel ratio becomes the stoichiometric air-fuel ratio. When the fuel injection amount is controlled so that the air-fuel ratio becomes the stoichiometric air-fuel ratio in this way, the oxygen storage amount in the exhaust purification catalyst 32 decreases compared to when the fuel is cut, so the catalyst bed temperature θ is excessively high. It will not rise.

According to this embodiment described above, in addition to the effects (1) to (3) of the first embodiment, the following effects can be achieved.
(5) When it is determined that the catalyst bed temperature θ when the blipping control is executed is higher than the determination temperature θK, the throttle opening degree TA is changed to the open side to increase the intake air amount GA. ing. Thereby, the exhaust purification catalyst 32 can be cooled by a large amount of exhaust gas, that is, intake air during the fuel cut, and an excessive temperature rise of the exhaust purification catalyst 32 can be suppressed.

(Other embodiments)
In addition, the embodiment of the present invention is not limited to the above-described embodiments, and can be carried out, for example, in the following manner. The following modifications are not applied only to the above-described embodiment, and different modifications can be combined with each other.

  In the first embodiment, when it is determined that the catalyst bed temperature θ is higher than the determination temperature θK during the downshift during the deceleration fuel cut, the blipping control itself is prohibited. Fuel injection amount, that is, either the basic fuel injection amount Q1 or the correction amount Q2, or both the basic fuel injection amount Q1 and the correction amount Q2, or a correction correction for increasing the basic fuel injection amount Q1 by the correction amount Q2. May be prohibited. Even with such a configuration, the effects (1) or (4), (2), and (3) described above can be achieved.

  In the second embodiment, when it is determined that the catalyst bed temperature θ is higher than the determination temperature θK1 during the downshift during the deceleration fuel cut, the blipping control itself is prohibited and the catalyst bed temperature θ is higher than the determination temperature θK2. Is determined to be high, the basic fuel injection amount Q1 at the time of blipping control is decreased. When it is determined that the catalyst bed temperature θ is higher than the determination temperature θK1, the basic fuel injection amount Q1 is corrected by the correction amount Q2. The increase correction of the fuel injection amount Q1 is prohibited, that is, the correction amount Q2 is set to “0”, and when it is determined that the catalyst bed temperature θ is higher than the determination temperature θK2, although the increase correction is performed, the correction amount Q2 is decreased. Such a configuration can also be adopted. Further, when it is determined that the catalyst bed temperature θ is higher than the determination temperature θK1, the basic fuel injection amount Q1 is corrected to decrease, and when it is determined that the catalyst bed temperature θ is higher than the determination temperature θK2, the correction amount Q2 is further increased. You may employ | adopt the structure of reducing weight. Even in these configurations, the effects (1) to (4) described above can be achieved.

  When reducing the basic fuel injection amount Q1 and the correction amount Q2 for correcting the increase in the second embodiment and each of the modifications described above, for example, the basic fuel injection amount Q1 is increased in the amount of decrease, and the correction amount Q2 It is also possible to set the amount of weight reduction by weighting, for example, by reducing the amount of weight reduction.

  -About the reduction | decrease of the basic fuel injection amount Q1 and the correction amount Q2 in 2nd Embodiment and said each modification, this can also be changed according to catalyst bed temperature (theta). That is, as the estimated catalyst bed temperature θ is higher, the degree of opening of the throttle opening TA in the blipping control is reduced to reduce the basic fuel injection amount Q1 from the normal request, or the catalyst bed temperature θ is higher. As occasion demands, the degree of reduction of the correction amount Q2 may be increased. Even if it is such a structure, there can exist the effect of (2)-(4) mentioned above.

  In the third embodiment, when the catalyst bed temperature θ is higher than the determination temperature θK, the throttle opening TA is changed to the open side, and then the blipping control is prohibited. Thus, it is possible to adopt a configuration in which the basic fuel injection amount Q1 during the blipping control is reduced, the increase correction by the correction amount Q2 is prohibited, or the correction amount Q2 is reduced.

  In the third embodiment, when the catalyst bed temperature θ is higher than the determination temperature θK, the throttle opening degree TA is changed to the open side and the blipping control is prohibited, but the throttle is not prohibited without the blipping control being prohibited. Only change of the opening degree TA may be executed.

  In each of the above embodiments, the ignition timing retarding process and the fuel injection amount increasing correction process are performed in the blipping control. However, depending on the specifications such as the compression ratio of the internal combustion engine 10, the ignition timing retarding process is performed. It is not always necessary to perform the processing and the fuel injection amount increase correction processing. Incidentally, the rise in the catalyst bed temperature θ is mainly due to the emission of unburned fuel components accompanying the increase correction of the basic fuel injection amount Q1 by the correction amount Q2, but the oxygen storage of the exhaust purification catalyst 32 during the fuel cut. Since the amount increases, an excessive increase in the catalyst bed temperature θ can occur even when such an increase correction is not performed. In this case, the increase amount Δθ of the catalyst bed temperature θ accompanying the blipping control can be calculated based on the integrated value ΣQ1 of the basic fuel injection amount Q1 during the period in which the fuel injection is executed by the blipping control. Even in this configuration, the effects (1) to (5) can be achieved.

  In each of the above embodiments, the blipping control is prohibited based on the comparison result between the catalyst bed temperature θ and the determination temperatures θK (θK1), θK2, the fuel injection amount is decreased, and the intake air amount GA is increased during the control. In addition, a suppression process for suppressing an increase in the catalyst bed temperature θ is performed. However, without making such a comparison, for example, the degree of decrease in the fuel injection amount is increased as the catalyst bed temperature θ is higher, or the degree of increase in the intake air amount GA is increased as the catalyst bed temperature θ is higher. The said suppression process can also be performed in the aspect.

  In each of the above embodiments, the increase amount Δθ of the catalyst bed temperature θ is calculated based on the total fuel increase amount ΣQ2 of the increase correction accompanying the blipping control, but the basic fuel injection amount Q1 during the blipping control and The integrated value ΣQ1 of the basic fuel injection amount Q1 is calculated based on the time when fuel injection is performed in the blipping control, and the increase amount Δθ of the catalyst bed temperature θ is calculated based on the integrated value ΣQ1. Good. Further, the increase amount Δθ of the catalyst bed temperature θ may be calculated based on an addition value ΣQT obtained by adding the integrated value ΣQ1 and the total fuel increase amount ΣQ2.

  In each of the above embodiments, the throttle opening degree TA is changed to the open side in order to increase the intake air amount GA, but a variable valve mechanism that can change the maximum lift amount and lift period of the intake valve is provided. In the case of the internal combustion engine provided, in order to increase the intake air amount GA, the variable valve mechanism can be controlled to increase the maximum lift amount and the lift period.

  In each of the above embodiments, the catalyst bed temperature θ during the period excluding the blipping control is estimated based on the engine operating state such as the engine speed NE, the accelerator opening ACCP, the intake air amount, etc. It can also be directly detected by a catalyst bed temperature sensor provided directly on the purification catalyst 32 or can be estimated based on a detection value of an exhaust temperature sensor provided downstream of the exhaust purification catalyst 32 in the exhaust passage 31.

  In each of the above embodiments, a vehicle equipped with the automatic transmission 40 having the torque converter 41 and the lock-up mechanism 45 that locks up when a predetermined lock-up condition is satisfied is exemplified. A transmission referred to as a multi-mode manual transmission and the like, and a clutch for connecting / disconnecting the input shaft of the transmission and the output shaft of the internal combustion engine, based on the shift operation of the driver. The present invention can be applied even to a vehicle that can be automatically performed.

  In each of the above-described embodiments, the six-speed automatic transmission 40 in which the gear ratio is switched to six stages is used. However, the gear stage is not limited to six stages. That is, it may be 5 stages or less and 7 stages or more.

  In each of the above embodiments, the full lockup type that operates the lockup mechanism 45 is adopted regardless of the shift speed from 1st to 6th. However, the mode of operating the lockup mechanism 45 is as follows. It is not limited to this. That is, the present invention is also applied to a mechanism that operates the mechanism 45 only at a high speed stage.

  DESCRIPTION OF SYMBOLS V ... Vehicle, 1 ... Accelerator pedal, 10 ... Internal combustion engine, 11 ... Output shaft, 21 ... Intake passage, 22 ... Throttle valve, 31 ... Exhaust passage, 32 ... Exhaust purification catalyst, 40 ... Automatic transmission, 41 ... Torque converter , 42 ... Transmission gear mechanism, 43 ... Input shaft, 44 ... Output shaft, 45 ... Lock-up mechanism, 46 ... Drive wheel, 50 ... Electronic control unit, 51 ... Accelerator position sensor, 52 ... Air flow meter, 53 ... Input rotation speed Sensor 54... Output rotation speed sensor 55. Shift sensor 56. Shift sensor 57.

Claims (7)

  An internal combustion engine having an output shaft and an exhaust passage, a stepped automatic transmission having an input shaft, connecting or disconnecting the output shaft and the input shaft, and when the automatic transmission downshifts, the output shaft and the A control device for a vehicle including a mechanical clutch for cutting an input shaft, and an exhaust purification catalyst disposed in the exhaust passage,
  When the vehicle is decelerating, performing a deceleration fuel cut to stop fuel injection of the internal combustion engine;
  Fuel is injected into the internal combustion engine when the deceleration fuel cut is being performed, when the automatic transmission is downshifted, and when the catalyst bed temperature, which is the temperature of the exhaust purification catalyst, is equal to or lower than a determination temperature. Execute the blipping control,
  In the blipping control, injection is made to the internal combustion engine so that a difference between the rotational speed of the output shaft of the internal combustion engine and the rotational speed of the input shaft of the automatic transmission is reduced by downshifting the automatic transmission. The basic fuel injection amount, which is the amount of fuel to be set, is set and retarded from the ignition timing of the internal combustion engine that matches the basic fuel injection amount that has not been corrected to increase so that the occurrence of knocking or shock is suppressed. A retard amount of the ignition timing is set according to the basic fuel injection amount, a correction amount for increasing the basic fuel injection amount according to the retard amount of the ignition timing is set, and the correction amount Injecting fuel into the internal combustion engine based on the basic fuel injection amount corrected for increase by
  The blipping control is not performed when the deceleration fuel cut is being performed, and when the automatic transmission is downshifted, and when the catalyst bed temperature is higher than the determination temperature,
  Or
  When the deceleration fuel cut is being performed, and when the automatic transmission is downshifted, and when the catalyst bed temperature is higher than the determination temperature, the blipping control is executed, and the catalyst bed temperature Less fuel is injected into the internal combustion engine than the fuel injected into the internal combustion engine by the blipping control executed when the temperature is equal to or lower than the determination temperature.
  Vehicle control device.   When the catalyst bed temperature is higher than the determination temperature, the intake air amount of the internal combustion engine when the blipping control is not executed, and when the catalyst bed temperature is equal to or lower than the determination temperature, the blipping control is executed. Increasing the intake air amount of the internal combustion engine when
  Or
  When the catalyst bed temperature is higher than the determination temperature, the intake air amount of the internal combustion engine is increased more than when the catalyst bed temperature is less than or equal to the determination temperature, the blipping control is executed, and the catalyst bed temperature is Less fuel is injected into the internal combustion engine than the fuel injected into the internal combustion engine by the blipping control executed when the temperature is equal to or lower than the determination temperature.
  The vehicle control device according to claim 1.   An internal combustion engine having an output shaft and an exhaust passage, a stepped automatic transmission having an input shaft, connecting or disconnecting the output shaft and the input shaft, and when the automatic transmission downshifts, the output shaft and the A control device for a vehicle including a mechanical clutch for cutting an input shaft, and an exhaust purification catalyst disposed in the exhaust passage,
  When the vehicle is decelerating, performing a deceleration fuel cut to stop fuel injection of the internal combustion engine;
  The catalyst bed temperature, which is the temperature of the exhaust purification catalyst, reduces the exhaust purification function of the exhaust purification catalyst when the automatic fuel transmission is downshifted and when the deceleration fuel cut is executed. When not suggested, perform a blipping control to inject fuel into the internal combustion engine,
  In the blipping control, injection is made to the internal combustion engine so that a difference between the rotational speed of the output shaft of the internal combustion engine and the rotational speed of the input shaft of the automatic transmission is reduced by downshifting the automatic transmission. The basic fuel injection amount, which is the amount of fuel to be set, is set and retarded from the ignition timing of the internal combustion engine that matches the basic fuel injection amount that has not been corrected to increase so that the occurrence of knocking or shock is suppressed. A retard amount of the ignition timing is set according to the basic fuel injection amount, a correction amount for increasing the basic fuel injection amount according to the retard amount of the ignition timing is set, and the correction amount Injecting fuel into the internal combustion engine based on the basic fuel injection amount corrected for increase by
  When performing the deceleration fuel cut, when the automatic transmission is downshifted, and when the catalyst bed temperature indicates that the exhaust purification function of the exhaust purification catalyst is degraded, Do not perform blipping control,
  Or
  When performing the deceleration fuel cut, when the automatic transmission is downshifted, and when the catalyst bed temperature indicates that the exhaust purification function of the exhaust purification catalyst is degraded, Performing blipping control and causing the internal combustion engine to inject less fuel than the fuel to be injected into the internal combustion engine by the blipping control performed when not so suggested
  Vehicle control device.   When the exhaust gas purification function of the exhaust gas purification catalyst is suggested by the catalyst bed temperature, the intake air amount of the internal combustion engine when the blipping control is not executed is not so suggested To increase the intake air amount of the internal combustion engine when the blipping control is performed.
  Or
  When the catalyst bed temperature suggests that the exhaust purification function of the exhaust purification catalyst is reduced, the intake air amount of the internal combustion engine is increased more than when it is not so suggested, and the blipping control is performed. Less than the amount of fuel injected into the internal combustion engine by the blipping control performed when not so suggested
  The vehicle control device according to claim 3.   An internal combustion engine having an output shaft and an exhaust passage, a stepped automatic transmission having an input shaft, connecting or disconnecting the output shaft and the input shaft, and when the automatic transmission downshifts, the output shaft and the A control device for a vehicle including a mechanical clutch for cutting an input shaft, and an exhaust purification catalyst disposed in the exhaust passage,
  When the vehicle is decelerating, performing a deceleration fuel cut to stop fuel injection of the internal combustion engine;
  When the deceleration fuel cut is being performed, when the automatic transmission is downshifted, and when the catalyst bed temperature, which is the temperature of the exhaust purification catalyst, is equal to or lower than a first determination temperature, fuel is supplied to the internal combustion engine. The blipping control to inject
  In the blipping control, injection is made to the internal combustion engine so that a difference between the rotational speed of the output shaft of the internal combustion engine and the rotational speed of the input shaft of the automatic transmission is reduced by downshifting the automatic transmission. The basic fuel injection amount, which is the amount of fuel to be set, is set and retarded from the ignition timing of the internal combustion engine that matches the basic fuel injection amount that has not been corrected to increase so that the occurrence of knocking or shock is suppressed. A retard amount of the ignition timing is set according to the basic fuel injection amount, a correction amount for increasing the basic fuel injection amount according to the retard amount of the ignition timing is set, and the correction amount Injecting fuel into the internal combustion engine based on the basic fuel injection amount corrected for increase by
  When the deceleration fuel cut is being performed, and when the automatic transmission is downshifted, the catalyst bed temperature is higher than the first determination temperature and higher than the first determination temperature. When the temperature is lower than a second determination temperature, the blipping control is executed, and less fuel is injected than the fuel injected into the internal combustion engine by the blipping control executed when the catalyst bed temperature is lower than the first determination temperature. Injecting into the internal combustion engine,
  The blipping control is not performed when the deceleration fuel cut is being performed, and when the automatic transmission is downshifted, and when the catalyst bed temperature is higher than the second determination temperature,
  Or
  When the deceleration fuel cut is being performed, when the automatic transmission is downshifted, and when the catalyst bed temperature is higher than the second determination temperature, the blipping control is performed, and the catalyst The internal combustion engine is injected with less fuel than the fuel injected into the internal combustion engine by the blipping control executed when the bed temperature is higher than the first determination temperature and lower than the second determination temperature.
  Vehicle control device.   An internal combustion engine having an output shaft and an exhaust passage, a stepped automatic transmission having an input shaft, connecting or disconnecting the output shaft and the input shaft, and when the automatic transmission downshifts, the output shaft and the A control device for a vehicle including a mechanical clutch for cutting an input shaft, and an exhaust purification catalyst disposed in the exhaust passage,
  When the vehicle is decelerating, performing a deceleration fuel cut to stop fuel injection of the internal combustion engine;
  From the relationship between the catalyst bed temperature, which is the temperature of the exhaust purification catalyst, and the first determination temperature, when the deceleration fuel cut is being performed, and when the automatic transmission is downshifted, the catalyst bed temperature. When it is not suggested that there is a high possibility that the catalyst bed temperature will reach the second determination temperature, which is a determination temperature higher than the first determination temperature, due to the fluctuation of the engine, the blipping control for injecting fuel to the internal combustion engine is performed. Run,
  In the blipping control, injection is made to the internal combustion engine so that a difference between the rotational speed of the output shaft of the internal combustion engine and the rotational speed of the input shaft of the automatic transmission is reduced by downshifting the automatic transmission. The basic fuel injection amount, which is the amount of fuel to be set, is set and retarded from the ignition timing of the internal combustion engine that matches the basic fuel injection amount that has not been corrected to increase so that the occurrence of knocking or shock is suppressed. A retard amount of the ignition timing is set according to the basic fuel injection amount, a correction amount for increasing the basic fuel injection amount according to the retard amount of the ignition timing is set, and the correction amount Injecting fuel into the internal combustion engine based on the basic fuel injection amount corrected for increase by
  There is a high possibility that the catalyst bed temperature will reach the second determination temperature when the deceleration fuel cut is being performed, when the automatic transmission is downshifted, and due to fluctuations in the catalyst bed temperature. When it is suggested by the relationship between the catalyst bed temperature and the first determination temperature, the blipping control is executed, and the internal combustion engine is injected by the blipping control executed when not so suggested. Injecting less fuel than the fuel into the internal combustion engine,
  When the deceleration fuel cut is being performed, and when the automatic transmission is downshifted, and the exhaust purification function of the exhaust purification catalyst is reduced, the catalyst bed temperature and the second determination temperature Do not perform the blipping control when suggested by the relationship,
  Or
  When the deceleration fuel cut is being performed, and when the automatic transmission is downshifted, and the exhaust purification function of the exhaust purification catalyst is reduced, the catalyst bed temperature and the second determination temperature The blipping control is performed when suggested by a relationship, and the internal combustion engine is injected with less fuel than the fuel that is injected into the internal combustion engine by the blipping control that is performed when not implied.
  Vehicle control device.   When the decelerating fuel cut is being performed, and when the automatic transmission is downshifting, when the decelerating fuel cut is being performed, the intake of the internal combustion engine is greater than before the automatic transmission is downshifting. Increase the air volume,
  Based on the increased intake air amount of the internal combustion engine, an air / fuel ratio richer than the stoichiometric air / fuel ratio is set as a target air / fuel ratio, and the basic fuel injection amount is set based on the air / fuel ratio.
  The vehicle control device according to any one of claims 1 to 6.

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