Vehicle control device

Abstract

To suppress a change in vehicle deceleration due to the stop of a fuel cutoff during deceleration.SOLUTION: During the deceleration of a vehicle, an electronic control unit 26 executes a deceleration fuel cutoff for stopping fuel injection to an engine 10, and deceleration lockup for bringing a lockup clutch 15 into an engagement state. Then, the electronic control unit 26 ends the deceleration fuel cutoff and deceleration lockup in response to the fulfillment of a recovery condition. On the other hand, when a request to suppress the heat-up of a filter device 25 is made before the fulfillment of the recovery condition, the electronic control unit 26 stops the deceleration fuel cutoff, but continues the deceleration lockup.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle control device.

Background Art

[0002] By the way, there is a vehicle equipped with a lock-up clutch that mechanically engages an engine and a transmission. In such a vehicle, in order to extend the fuel cut-off time during deceleration, deceleration lock-up may be performed to engage the lock-up clutch during deceleration.

[0003] As a vehicle control device that performs such deceleration lock-up, the device described in Patent Document 1 is known. The engine of the vehicle controlled by the vehicle control device in this document is provided with a filter device that collects particulate matter (PM) in the exhaust gas. And when it becomes necessary to suppress the temperature rise of the filter device during the execution of fuel cut-off, the vehicle control device stops the fuel cut-off and resumes the combustion of the engine. Further, the vehicle control device releases the lock-up clutch together with the stop of the fuel cut-off.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When shifting from a state where the engine performs fuel cut-off and the lock-up clutch is engaged to a state where the engine performs combustion operation and the lock-up clutch is released, the engine braking effect becomes weak. Therefore, when the fuel cut-off is stopped during the execution of deceleration lock-up, the deceleration feeling of the vehicle may change, and the passengers may feel discomfort.

Means for Solving the Problems

[0006] The vehicle control device that solves the above problems is a device that controls a vehicle having a lock-up clutch that mechanically connects an engine and a transmission. The vehicle control device performs a deceleration fuel cut process that performs a fuel cut of the engine during deceleration of the vehicle, and a deceleration lock-up process that engages the lock-up clutch during the execution of the fuel cut by the deceleration fuel cut process. By engaging the lock-up clutch during the execution of the fuel cut, a decrease in the engine speed can be suppressed. And thereby, the fuel cut period can be extended. Note that in the deceleration fuel cut process, when a predetermined return condition is satisfied, the fuel cut is terminated and the combustion of the engine is restarted.

[0007] Also, when the vehicle control device aborts the fuel cut by the deceleration fuel cut process before the return condition is satisfied, it performs a continuation process of continuing the engaged state of the lock-up clutch even after the restart of the combustion of the engine. If the engaged state of the lock-up clutch is released together with the cancellation of the fuel cut, the deceleration of the vehicle significantly decreases. On the other hand, in the above vehicle control device, since the engaged state of the lock-up clutch is maintained even after the cancellation of the fuel cut, a decrease in the deceleration of the vehicle after the cancellation of the fuel cut is suppressed. Therefore, the vehicle control device has an effect of suppressing a change in the vehicle deceleration accompanying the cancellation of the deceleration fuel cut.

[0008] When the above engine is provided with a filter device that collects particulate matter in the exhaust gas, the cancellation of the fuel cut before the return condition is satisfied is performed, for example, when the temperature of the filter device is estimated to be equal to or higher than a predetermined value.

[0009] The vehicle control device may be configured to execute slip control for performing feedback control on the engaging force of the lock-up clutch so that the slip amount of the lock-up clutch becomes the target slip amount. When the vehicle control device executes the slip control during the continuation of the engaged state of the lock-up clutch by continuous processing, it may be configured to execute the slip control with a value larger than that when the slip control is executed during fuel cut as the value of the target slip amount. Further, the vehicle control device that executes the slip control may be configured to execute the slip control with a value smaller than that when the slip control is executed during fuel cut as the value of the target slip amount when the slip control is executed during the continuation of the engaged state of the lock-up clutch by continuous processing. Furthermore, the vehicle control device that executes the slip control may be configured to execute the slip control with the same value as that when it is assumed that the fuel cut is being performed without being stopped as the value of the target slip amount when the slip control is executed during the continuation of the engaged state of the lock-up clutch by continuous processing.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0011] Hereinafter, an embodiment of the vehicle control device will be described in detail with reference to FIGS. 1 to 4. <Configuration of the vehicle drive system> First, with reference to FIG. 1, the configuration of the drive system of the vehicle to which the vehicle control device of this embodiment is applied will be described. An engine 10 is mounted on the vehicle. The crankshaft 11, which is the output shaft of the engine 10, is connected to the transmission input shaft 14, which is the input shaft of the automatic transmission 13, via a torque converter 12, which is a fluid coupling having a torque amplification function. The torque converter 12 is provided with a lock-up clutch 15 that mechanically connects the engine 10 and the automatic transmission 13. The lock-up clutch 15 engages in response to the supply of hydraulic oil to mechanically connect the crankshaft 11 and the transmission input shaft 14. On the other hand, the transmission output shaft 16, which is the output shaft of the automatic transmission 13, is connected to the left and right wheels 18 via a differential 17. Note that a hydraulic control circuit 29 for controlling the hydraulic pressure of the lock-up clutch 15 and the automatic transmission 13 is installed in the vehicle.

[0012] The engine 10 includes a plurality of cylinders 19 that perform combustion, an intake passage 20 that is an intake introduction passage to each cylinder 19, and an exhaust passage 23 that is an exhaust discharge passage from each cylinder 19. Further, an injector 22 that injects fuel into the intake air is provided for each cylinder 19 in the engine 10. A throttle valve 21 for adjusting the flow rate of the intake air flowing inside is installed in the intake passage 20. A catalytic device 24 for exhaust purification is installed in the exhaust passage 23. Further, a filter device 25 for collecting particulate matter (PM) in the exhaust gas is installed in a portion of the exhaust passage 23 downstream of the catalytic device 24.

[0013] <Configuration of the vehicle control device> An electronic control unit 26 as a vehicle control device is installed in the vehicle. The electronic control unit 26 is configured as an electronic control unit having an arithmetic processing device 27 and a storage device 28. Programs and data for vehicle control are stored in the storage device 28. The arithmetic processing device 27 executes various processes for vehicle control by reading and executing programs from the storage device 28.

[0014] The electronic control unit 26 receives detection signals from sensors installed in various parts of the vehicle, such as the crank angle sensor 30, the input rotation speed sensor 31, the vehicle speed sensor 32, and the accelerator pedal sensor 33. The crank angle sensor 30 is a sensor that detects the rotational phase of the crankshaft 11. Note that the electronic control unit 26 calculates the engine speed NE, that is, the rotational speed of the crankshaft 11, based on the detection result of the crank angle sensor 30. The input rotation speed sensor 31 is a sensor that detects the input rotation speed NI, that is, the rotational speed of the transmission input shaft 14. The vehicle speed sensor 32 is a sensor that detects the vehicle speed V, that is, the traveling speed of the vehicle. The accelerator pedal sensor 33 is a sensor that detects the accelerator opening ACC, that is, the amount of operation of the driver's accelerator pedal.

[0015] Based on the detection results of these sensors, the electronic control unit 26 controls the operations of the engine 10, the lock-up clutch 15, the automatic transmission 13, etc. Specifically, the electronic control unit 26 controls the operation of the engine 10 through operations such as the opening of the throttle valve 21 and the fuel injection amount of the injector 22. Also, the electronic control unit 26 controls the operations of the lock-up clutch 15 and the automatic transmission 13 through the operation of the hydraulic control circuit 29.

[0016] <Suppression of the temperature rise of the filter device 25> When the vehicle decelerates, the electronic control unit 26 performs deceleration fuel cut, which temporarily stops the fuel injection of the engine 10. Also, when the vehicle decelerates, the electronic control unit 26 performs deceleration lock-up in which the lock-up clutch 15 is engaged to extend the fuel cut time.

[0017] On the one hand, as described above, the engine 10 is provided with a filter device 25 that collects PM in the exhaust. When fuel cut is performed, the exhaust flowing through the exhaust passage 23 is replaced with fresh air, and oxygen is supplied to the filter device 25. Then, the PM deposited on the filter device 25 is burned by the supplied oxygen. If fuel cut continues for a long time with a large amount of PM deposited on the filter device 25, there is a risk of overheating of the filter device 25 due to heat generation from the combustion of PM. In contrast, when there is a possibility of overheating of the filter device 25 if fuel cut continues, the electronic control unit 26 requests suppression of the temperature rise of the filter device 25. Then, the electronic control unit 26 suppresses overheating of the filter device 25 by stopping fuel cut in response to the request.

[0018] FIG. 2 shows a flowchart of a request determination routine executed by the electronic control unit 26 to determine whether to request suppression of the temperature rise of the filter device 25. The filter device 25 repeatedly executes this routine at each predetermined control cycle during the running of the vehicle.

[0019] When starting this routine, first, in step S100, the electronic control unit 26 calculates the maximum F / C time based on the PM collection amount of the filter device 25. The electronic control unit 26 estimates the PM collection amount of the filter device 25 based on the operating state of the engine 10, such as the intake air amount, air-fuel ratio, etc. The maximum F / C time represents the maximum value of the continuous time of fuel cut that can be performed without causing overheating of the filter device 25. And when the PM collection amount is large, the electronic control unit 26 calculates a shorter time as the value of the maximum F / C time than when it is small.

[0020] Subsequently, in step S110, the electronic control unit 26 determines whether the F / C time is equal to or greater than the maximum F / C time. The F / C time represents the duration of the fuel cut up to the present. When the fuel cut is not being performed, the F / C time becomes "0". And when the F / C time is equal to or greater than the maximum F / C time (YES), the electronic control unit 26 determines in step S120 that there is a requirement to suppress the temperature rise of the filter device 25 and ends the processing of this routine in the current control cycle. On the other hand, when the F / C time is less than the maximum F / C time (NO), the electronic control unit 26 determines in step S130 that there is no requirement to suppress the temperature rise of the filter device 25 and ends the processing of this routine in the current control cycle. Note that as described above, the maximum F / C time is calculated as the maximum value of the duration of the fuel cut that can be performed without causing overheating of the filter device 25. Therefore, when the F / C time becomes equal to or greater than the maximum F / C time, it is a case where it is estimated that the temperature of the filter device 25 is equal to or higher than the temperature regarded as overheating.

[0021] <Deceleration control> Next, with reference to FIG. 3, the control during vehicle deceleration such as fuel cut during deceleration and lock-up during deceleration will be described. FIG. 3 shows a flowchart of a deceleration control routine executed by the electronic control unit 26 for the control during vehicle deceleration. The electronic control unit 26 repeatedly executes this routine at every predetermined control cycle during the running of the vehicle.

[0022] When starting this routine, first, in step S200, the electronic control unit 26 determines whether the accelerator opening ACC is "0%". That is, in step S200, the electronic control unit 26 determines whether the driver has released the accelerator pedal. And when the accelerator opening ACC is not "0%" (NO), the electronic control unit 26 turns off the F / C flag, the LU flag, and the F / C cancellation flag respectively in step S210 and ends the processing of this routine in the current control cycle.

[0023] Note that the F / C flag is a flag indicating whether fuel cut during deceleration is in progress. The electronic control unit 26 starts fuel cut during deceleration when the F / C flag switches from off to on. Also, the electronic control unit 26 ends fuel cut during deceleration and resumes the combustion of the engine 10 when the F / C flag switches from on to off. On the other hand, the LU flag is a flag indicating whether lock-up during deceleration is in progress. The electronic control unit 26 starts lock-up during deceleration when the LU flag switches from off to on. Also, the electronic control unit 26 ends lock-up during deceleration when the LU flag switches from on to off. As described above, when the accelerator opening ACC is not "0%" (S200: NO), in step S210, the F / C flag and the LU flag are set to off. Therefore, fuel cut during deceleration and lock-up during deceleration are ended in response to the driver depressing the accelerator pedal.

[0024] On the other hand, when the accelerator opening ACC is "0%" (S200: YES), the electronic control unit 26 determines whether the LU flag is on in step S220. Then, when the LU flag is on (YES), the electronic control unit 26 proceeds to step S250, and when it is off (NO), it proceeds to step S230 for each process.

[0025] When the LU flag is off and the process proceeds to step S230, the electronic control unit 26 determines in step S230 whether the engine speed NE is equal to or higher than "N1" and the vehicle speed V is equal to or higher than "V1". "N1" represents the F / C start engine speed, which is the lower limit of the engine speed NE at which fuel cut during deceleration starts. Also, "V1" represents the F / C start vehicle speed, which is the lower limit of the vehicle speed V at which fuel cut during deceleration starts. When the engine speed NE is equal to or higher than "N1" and the vehicle speed V is equal to or higher than "V1" (S230: YES), the electronic control unit 26 proceeds with the process to step S240. Then, in step S240, the electronic control unit 26 turns on the F / C flag and the LU flag respectively, and ends the process of this routine in the current control cycle. Also, when the engine speed NE is less than "N1" or the vehicle speed V is less than "V1" (S230: NO), the electronic control unit 26 ends the process of this routine in the current control cycle as it is. Thus, when the accelerator opening ACC becomes "0%" in a state where the engine speed NE is equal to or higher than "N1" and the vehicle speed V is equal to or higher than "V1", the electronic control unit 26 starts fuel cut during deceleration and lock-up during deceleration.

[0026] On the other hand, when the LU flag is on and the process proceeds to step S250, the electronic control unit 26 determines, in step S250, whether the engine speed NE is less than or equal to "N2" or the vehicle speed V is less than or equal to "V2". "N2" represents the F / C return speed, which is the lower limit value of the engine speed NE at which fuel cut is implemented during deceleration. A positive value smaller than the above-mentioned "N1" is set for "N2". On the other hand, "V2" represents the F / C return vehicle speed, which is the lower limit value of the vehicle speed V at which fuel cut is implemented during deceleration. A positive value smaller than the above-mentioned "V1" is set for "V2". Then, when the engine speed NE is less than or equal to "N2" or the vehicle speed V is less than or equal to "V2" (S250: YES), the electronic control unit 26 proceeds to the above-mentioned step S210. That is, the electronic control unit 26 ends the lock-up during deceleration when either the engine speed NE becomes less than or equal to "N2" or the vehicle speed V becomes less than or equal to "V2". Also, at this time, if the F / C flag is on and fuel cut during deceleration is being implemented, the electronic control unit 26 also ends the fuel cut during deceleration accordingly.

[0027] On the other hand, when the engine speed NE exceeds "N2" and the vehicle speed V exceeds "V2" (S250: NO), the electronic control unit 26 proceeds to step S260. Then, in step S260, the electronic control unit 26 determines whether there is a requirement for suppressing the temperature rise of the filter device 25. If there is no requirement for suppressing the temperature rise (NO), the electronic control unit 26 ends the processing of this routine in the current control cycle as it is. In this case, the electronic control unit 26 continues the lock-up during deceleration. Also, in this case, if the electronic control unit 26 is implementing fuel cut during deceleration, it also continues the fuel cut during deceleration.

[0028] On the other hand, when there is a requirement for suppressing temperature rise (S250: YES), the electronic control unit 26, in step S270, after turning off the F / C flag, ends the processing of this routine in the current control cycle. In this way, when the temperature rise suppression of the filter device 25 is required, the electronic control unit 26 ends the fuel cut during deceleration. However, at this time, the LU flag is maintained on. That is, even when the temperature rise suppression of the filter device 25 is required, the electronic control unit 26 continues the lock-up during deceleration.

[0029] Note that in this embodiment, by turning on the F / C flag in step S240 of FIG. 3, the deceleration fuel cut process for implementing the fuel cut of the engine 10 during vehicle deceleration is started. Also, by turning on the LU flag in the same step S240, the deceleration lock-up process for engaging the lock-up clutch 15 during the implementation of the fuel cut by the deceleration fuel cut process is started. Further, by turning off the F / C flag in step S270 of FIG. 3, when the cancellation of the fuel cut is required during the implementation of the fuel cut by the deceleration fuel cut process, the combustion of the engine 10 is restarted. And by not operating the LU flag in the same step S270, the continuous process of continuing the engaged state of the lock-up clutch 15 is implemented even after the restart of the combustion of the engine 10.

[0030] <Operational Effects of the Embodiment> The operation and effects of this embodiment will be described. FIGS. 4(A) to (F) show the transitions of the following parameters during vehicle deceleration. Note that FIG. 4(A) shows the transition of the accelerator opening ACC, FIG. 4(B) shows the requirement for suppressing temperature rise, FIG. 4(C) shows the F / C flag, FIG. 4(D) shows the LU flag, FIG. 4(E) shows the engine speed NE, and FIG. 4(F) shows the vehicle acceleration. In the case of FIG. 4, when the accelerator opening ACC becomes "0%" at time t1 during vehicle travel, the F / C flag and the LU flag are switched from off to on. That is, at time t1, the deceleration fuel cut and the deceleration lock-up are started.

[0031] When there is no requirement to suppress the temperature rise of the filter device 25 as described above, the switching of the F / C flag from ON to OFF is performed when any of the following situations (a) to (c) occurs. Situation (a) is when the engine speed NE becomes "N2" or less. Situation (b) is when the vehicle speed V becomes "V2" or less. Situation (c) is when the accelerator opening ACC is other than "0%", that is, when the accelerator pedal is depressed. In the deceleration fuel cut process, the establishment of any of the above situations (a) to (c) is set as the return condition for the deceleration fuel cut. On the other hand, when it is estimated that the temperature of the filter device 25 is equal to or higher than a predetermined temperature, in the requirement determination routine of FIG. 2, suppression of the temperature rise of the filter device 25 is required. In this case, the deceleration fuel cut process is stopped before the above return condition is established.

[0032] As shown by the broken line in FIG. 4(B), when the state where the suppression of the temperature rise of the filter device 25 is not required continues after time t1, both the deceleration fuel cut and the deceleration lock-up are continued until the return condition is satisfied. The transition of the F / C flag in this case is shown by the broken line in FIG. 4(C), and the transition of the vehicle acceleration in this case is shown by the broken line in FIG. 4(F).

[0033] Here, as shown by the solid line in FIG. 4(B), consider the case where the suppression of the temperature rise of the filter device 25 is required at time t2 during the execution of the deceleration fuel cut and the deceleration lock-up. When the electronic control unit 26 determines that the suppression of the temperature rise of the filter device 25 is required before the return condition is satisfied at time t2, as shown by the solid line in FIG. 4(C), the F / C flag is turned OFF to stop the deceleration fuel cut. When the deceleration fuel cut ends and the combustion of the engine 10 resumes, the supply of oxygen to the filter device 25 is interrupted, and the combustion of the deposited PM is delayed. Therefore, further temperature rise of the filter device 25 is suppressed.

[0034] On the one hand, the electronic control unit 26 extends the fuel cut period by suppressing a decrease in the engine speed NE by performing lock-up during deceleration in combination with fuel cut during deceleration. When the fuel cut during deceleration is stopped in response to the requirement of suppressing the temperature rise of the filter device 25, the continuation of the lock-up during deceleration becomes unnecessary for the purpose of extending the fuel cut period.

[0035] Here, as shown by the dashed-dotted line in FIG. 4(D), consider the case where the LU flag is also turned off at the time t2 when the F / C flag is turned off, and the lock-up during deceleration is also stopped. In addition, the transition of the engine speed NE in this case is shown by the dashed-dotted line in FIG. 4(E), and the transition of the vehicle deceleration in this case is shown by the dashed-dotted line in FIG. 4(F). Since the accelerator opening ACC is also "0%" after the time t2, the engine 10 after the restart of combustion performs idling operation. Therefore, when the lock-up during deceleration is also stopped together with the stop of the fuel cut during deceleration, the engine speed NE rapidly decreases to near the idle speed. Then, when the lock-up clutch 15 is released, the effect of the engine brake becomes weak, so the deceleration of the vehicle greatly decreases.

[0036] On the other hand, when the vehicle control device according to the present embodiment stops the fuel cut during deceleration before the return condition is satisfied, the lock-up during deceleration is continued. The transition of the LU flag in the case of the present embodiment is shown by the solid line in FIG. 4(D), and the transition of the vehicle acceleration in the case of the present embodiment is shown by the solid line in FIG. 4(F). The deceleration of the vehicle after the stop of the fuel cut during deceleration in this case decreases compared to the case where the fuel cut during deceleration is continued. However, since the lock-up during deceleration is continued, the decrease in the deceleration of the vehicle is limited compared to the case where the lock-up during deceleration is also stopped together with the fuel cut during deceleration.

[0037] According to the vehicle control device of the present embodiment described above, the following effects can be obtained. (1) In this embodiment, when the deceleration fuel cut is aborted and the combustion of the engine 10 is restarted before the return condition is satisfied, the deceleration lock-up is continued. As a result, the change in the vehicle deceleration before and after the abort of the deceleration fuel cut is reduced. Consequently, the deterioration of drivability due to the change in the vehicle deceleration can be suppressed.

[0038] (2) In this embodiment, when it is estimated that the temperature of the filter device 25 is equal to or higher than a predetermined temperature, the deceleration fuel cut is aborted. Therefore, overheating of the filter device 25 can be prevented.

[0039] (Other embodiments) This embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other as long as they are not technically contradictory.

[0040] <Slip control of the lock-up clutch 15> During the engagement of the lock-up clutch 15 for deceleration lock-up, slip control may be performed. Slip control is control that sets the lock-up clutch 15 in a slip state where some slippage occurs. During slip control, the electronic control unit 26 sets a target slip amount, which is the target value of the slip amount that is the rotational difference between the crankshaft 11 and the transmission input shaft 14. Further, the electronic control unit 26 obtains the actual value of the slip amount based on the detection results of the crank angle sensor 30 and the input rotation speed sensor 31. Then, the electronic control unit 26 performs feedback control of the engaging force of the lock-up clutch 15 so that the actual value of the slip amount approaches the target slip amount. More precisely, at this time, the electronic control unit 26 performs feedback control of the operating oil pressure supplied by the hydraulic control circuit 29 to the lock-up clutch 15. The configuration mode of the vehicle control device when slip control is performed during deceleration lock-up is shown below.

[0041] Line L1 in Fig. 5 shows an example of the setting mode of the target slip amount in slip control. Here, the target slip amount is set based on the vehicle speed V. Also, here, slip control is performed in the range where the predetermined vehicle speed V is "V3" or less. And in the range where the vehicle speed V exceeds "V3", the lock-up clutch 15 is fully engaged so that the crankshaft 11 and the transmission input shaft 14 rotate synchronously.

[0042] Now, as described above, the electronic control unit 26 performs a continuation process of continuing the engagement state of the lock-up clutch 15 even after restarting the combustion of the engine 10 due to the request to cancel the fuel cut during deceleration. That is, there are a case where slip control is executed during the continuation of lock-up during deceleration by the continuation process after the restart of combustion, and a case where slip control is executed during the execution of fuel cut during deceleration. In the following description, the slip control in the former case is described as slip control after F / C cancellation. Also, the slip control in the latter case is described as slip control during F / C. The target slip amount in each of the slip control during F / C and the slip control after F / C cancellation may be set according to any one of the following setting modes 1 to 3.

[0043] [Setting Mode 1] When executing slip control after F / C cancellation, a value larger than that when executing slip control during F / C is set as the value of the target slip amount. For example, in slip control during F / C, the target slip amount is set in the mode shown by line L1 in Fig. 5. And in slip control after F / C cancellation, the target slip amount is set in the mode shown by line L2 in Fig. 5. Immediately after the restart of combustion of the engine 10, rotational fluctuations of the engine 10 are likely to occur. The rotational fluctuations of the engine 10 are more likely to be transmitted to the vehicle power transmission system as the engagement of the lock-up clutch 15 is stronger. And when the rotational fluctuations are transmitted to the power transmission system, there is a possibility that vibrations and noises will occur in the vehicle body. On the other hand, when a large value is set for the target slip amount, the engagement of the lock-up clutch 15 becomes weaker. Therefore, if the target slip amount is set as described above, vibrations and noises of the vehicle body due to the rotational fluctuations of the engine 10 immediately after the restart of combustion can be suppressed.

[0044] [Setting Mode 2] When performing slip control after F / C interruption, set a smaller value as the target slip amount than when performing slip control during F / C. For example, in slip control during F / C, the target slip amount is set in the manner shown by line L1 in FIG. 5, while in slip control after F / C interruption, the target slip amount is set in the manner shown by line L3 in FIG. 5. In such a case, the decrease in vehicle deceleration before and after the cancellation of fuel cut during deceleration is reduced.

[0045] [Setting Mode 3] In both slip control after F / C interruption and slip control during F / C, set the target slip amount in a similar manner. That is, even when performing slip control after F / C interruption, the same value as when assuming slip control is being performed during F / C may be set as the value of the target slip amount. For example, in both slip control during F / C and slip control after F / C interruption, the target slip amount is set in the manner shown by line L1 in FIG. 5. In such a case, since there is no need to switch the content of slip control between during the execution of fuel cut during deceleration and after the cancellation of fuel cut during deceleration, the control design of slip control becomes easier.

[0046] Note that during the execution of lock-up during deceleration, the lock-up clutch 15 may be maintained in a fully engaged state without performing slip control. <Regarding Cancellation of Fuel Cut During Deceleration> In the above-described embodiment, when suppression of the temperature rise of the filter device 25 was required, the deceleration fuel cut was stopped before the return condition was satisfied. The deceleration fuel cut may be stopped under other conditions. For example, when the engine coolant temperature becomes equal to or lower than a threshold value, the deceleration fuel cut may be stopped and the combustion of the engine 10 may be restarted. In an extremely low temperature environment, if the deceleration fuel cut continues for a long time, the temperature of the engine 10 may drop to such an extent that smooth restart is not possible, or the temperature of the catalyst device 24 may drop until the catalyst becomes inactive. Therefore, if the deceleration fuel cut is stopped when the engine coolant temperature becomes equal to or lower than the threshold value during the execution of the deceleration fuel cut, deterioration of the restartability of the engine 10 and exhaust performance after the fuel cut ends can be suppressed. In any case, when the deceleration fuel cut is stopped before the return condition is satisfied, by continuing the deceleration lock-up even after the combustion restarts, deterioration of drivability due to changes in the vehicle deceleration can be suppressed.

[0047] <Regarding the setting of the target slip amount> In the above-described embodiment, the target slip amount was set based on the vehicle speed V, but the target slip amount may be set based on other parameters, for example, the engine speed NE. Further, the target slip amount may be set to a fixed value. Even in that case, different values may be set as the target slip amount value during the slip control during F / C and during the slip control after F / C cancellation.

Explanation of reference numerals

[0048] 10…Engine 11…Crankshaft 12…Torque converter 13…Automatic transmission 14…Transmission input shaft 15…Lock-up clutch 16…Transmission output shaft 17…Differential 18…Wheel 19…Cylinder 20…Intake passage 21…Throttle valve 22…Injector 23… Exhaust passage 24… Catalytic device 25… Filter device 26… Electronic control unit 27… Arithmetic processing unit 28… Memory device 29… Hydraulic control circuit 30… Crank angle sensor 31… Input rotation speed sensor 32… Vehicle speed sensor 33… Accelerator pedal sensor

Claims

1. An apparatus for controlling a vehicle having a lock-up clutch that mechanically connects an engine and a transmission, comprising: a deceleration fuel cut process that performs fuel cut of the engine during deceleration of the vehicle and resumes combustion of the engine by ending the fuel cut when a predetermined return condition is satisfied; a deceleration lock-up process that engages the lock-up clutch during the fuel cut by the deceleration fuel cut process; a continuation process that continues the engaged state of the lock-up clutch even after restarting combustion of the engine when the fuel cut by the deceleration fuel cut process is aborted before the return condition is satisfied; performing: executing slip control that performs feedback control of the engaging force of the lock-up clutch so that the slip amount of the lock-up clutch becomes a target slip amount; and when executing the slip control during the continuation of the engaged state of the lock-up clutch by the continuation process, executing the slip control with a value larger than the value of the target slip amount when executing the slip control during the fuel cut Vehicle control device.

2. An apparatus for controlling a vehicle having a lock-up clutch that mechanically connects an engine and a transmission, comprising: a deceleration fuel cut process that performs fuel cut of the engine during deceleration of the vehicle and resumes combustion of the engine by ending the fuel cut when a predetermined return condition is satisfied; a deceleration lock-up process that engages the lock-up clutch during the fuel cut by the deceleration fuel cut process; a continuation process that continues the engaged state of the lock-up clutch even after restarting combustion of the engine when the fuel cut by the deceleration fuel cut process is aborted before the return condition is satisfied; performing: executing slip control that performs feedback control of the engaging force of the lock-up clutch so that the slip amount of the lock-up clutch becomes a target slip amount; and when executing the slip control during the continuation of the engaged state of the lock-up clutch by the continuation process, executing the slip control with a value smaller than the value of the target slip amount when executing the slip control during the fuel cut Vehicle control device.

3. An apparatus for controlling a vehicle having a lock-up clutch that mechanically connects an engine and a transmission, a deceleration fuel cut process that performs fuel cut of the engine during deceleration of the vehicle and ends the fuel cut and resumes combustion of the engine when a predetermined return condition is satisfied, a deceleration lock-up process that engages the lock-up clutch during the execution of the fuel cut by the deceleration fuel cut process, a continuation process that continues the engaged state of the lock-up clutch even after the restart of combustion of the engine when the fuel cut by the deceleration fuel cut process is aborted before the return condition is satisfied, performs, slip control that performs feedback control of the engaging force of the lock-up clutch so that the slip amount of the lock-up clutch becomes a target slip amount, and when the slip control is executed during the continuation of the engaged state of the lock-up clutch by the continuation process, the slip control is executed with the same value as the value of the target slip amount when it is assumed that the fuel cut is being performed without being aborted. Vehicle control device.

4. The engine is provided with a filter device that collects particulate matter in the exhaust, The aborting of the fuel cut before the return condition is satisfied is performed when the temperature of the filter device is estimated to be equal to or higher than a predetermined temperature. The vehicle control device according to any one of claims 1 to 3.

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