JP2018017243A - Control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To switch a gear stage to a different gear stage without generating a large shock when it is determined that friction engagement elements (clutches C1 to C4 or the like) of an automatic transmission 3 are failed during the traveling of a vehicle.SOLUTION: A control device of a vehicle comprises an N-D control routine for changing a gear to a target gear stage while cooperating with the torque-down control of an engine 1 when the gear is switched to a D-range from an N-range during traveling. When it is determined that there is a risk of a fail in a friction engagement element by a "turbine blow" (step S201: fail determination means), a gear stage in which a friction engagement element having a risk of a fail is released is set as a target gear stage (S202), and after the gear is switched to the N-range once (S203), the gear is switched to the D-range once again, thus performing the N-D control routine (S204).SELECTED DRAWING: Figure 7

Description

  The present invention relates to a control device for a vehicle in which an engine and a stepped automatic transmission are mounted, and more particularly, the friction engagement element is caused by the rotation of an input shaft of the automatic transmission during running of the vehicle. This relates to the control when the engagement failure (failure) is determined.

  2. Description of the Related Art Conventionally, as an automatic transmission mounted on a vehicle such as an automobile, a stepped gear transmission mechanism that transmits engine driving force via a torque converter has been used. In this gear transmission mechanism, a clutch is used. A plurality of shift stages are established by selectively engaging or releasing a plurality of friction engagement elements such as a brake and a brake. Then, when the vehicle is traveling in the forward travel range such as the D range, a suitable gear position is selected according to the vehicle speed and the accelerator opening.

  While such a vehicle is running, any of the plurality of friction engagement elements forming the selected gear stage may cause engagement failure, and the engine torque may not be sufficiently transmitted to the output side. is there. In this case, the turbine rotation of the torque converter, that is, the rotation of the input shaft of the automatic transmission is greatly blown up (so-called turbine blowing). For example, in the vehicle automatic transmission of Patent Document 1, there is a risk of failure. A target shift stage where the engagement element is not engaged is set and switched to this.

Japanese Patent Laid-Open No. 03-199766

  However, if the shift control is performed in a state where the frictional engagement element is failing as in the conventional example, a large shock may occur. In other words, when one frictional engagement element is released for shifting, if the other frictional engagement element is poorly engaged, the input shaft rotation speed converges to the synchronous rotation speed after the shift is completed. This is because so-called backup engagement is performed, and another friction engagement element is suddenly engaged.

  Focusing on this point, an object of the present invention is to switch to another shift stage that can be established without generating a large shock when a failure of the friction engagement element of the automatic transmission is determined while the vehicle is running. That is.

  In order to achieve the above object, the present invention is directed to a control device for a vehicle equipped with an engine and a stepped automatic transmission, and the traveling control range of the automatic transmission is changed from the N range during traveling of the vehicle. When switching to the D range, ND control means is provided for performing shift control to the target gear stage (hereinafter also referred to as ND control) in cooperation with the torque reduction control of the engine.

  Further, a fail determination means for determining that there is a risk of failure in the engaged frictional engagement element when the input shaft rotation of the automatic transmission is greatly increased by a predetermined amount or more during traveling of the vehicle in the D range. Then, the gear position in which the frictional engagement element determined to be likely to fail is released is set as the target gear position, the travel control range is once switched to the N range, and then switched to the D range again. And a failure time control means for executing a shift control (ND control) by the ND control means.

  The D range of the travel control range is not only the so-called drive range but also the general forward travel range including the eco mode and the sport mode, and the N range is related to the D range. This is the so-called neutral range in which all frictional engagement elements that can be combined are released. The ND control mentioned above is one in which one of the two friction engagement elements for forming the target gear position in the D range is preferentially engaged with the other, for example, Japanese Patent Application Laid-Open No. 2009-2009. -299878.

  In the vehicle control apparatus according to the present invention, when the travel control range of the automatic transmission is in the D range while the vehicle is traveling, the input shaft rotation is greatly increased by a predetermined amount or more when the vehicle is traveling. The failure determination means determines that there is a risk of engagement failure (fail) in any of the plurality of friction engagement elements that are engaged at this gear. It should be noted that the input shaft rotation is greatly increased by a predetermined value or more, for example, when the rotation speed of the input shaft is rapidly increased by a predetermined value or more with respect to the rotation speed of the output shaft of the automatic transmission.

  Then, according to the failure determination, the failure time control means first sets the gear stage where the engaged friction engagement element is released at the current gear stage as the target gear stage, and the travel control range is temporarily set. , Switched to the N range. As a result, all the frictional engagement elements that can be engaged in the D range are released, and no malfunction occurs even if any of them is failed.

  Subsequently, the shift control (ND control) by the ND control means is executed, and the engine torque-down control suppresses the rising of the input shaft rotation, and two friction engagement elements that do not cause a failure. Are engaged to form a new target shift speed. At this time, as described above, one of the friction engagement elements is preferentially engaged with the other by the ND control, and the shock is suppressed together with the torque reduction of the engine.

  In this way, it is possible to switch to another gear position by engaging a friction engagement element that does not cause a failure without causing a large shock. As a result, the vehicle can be evacuated. In addition, it is preferable that the other shift stage to be switched as described above is the closest in the high speed stage than the current shift stage, and this makes it easier to further suppress the shock.

  As described above, according to the vehicle control apparatus of the present invention, the input shaft rotation of the automatic transmission that is in the D range during driving of the vehicle is greatly increased by a predetermined amount or more, and the friction engagement element fails. First, after switching to the N range and releasing all the frictional engagement elements, a new gear position is formed by ND control, so that a large shock is not generated. , It is possible to switch to another shift stage that can be established.

It is a schematic block diagram of the power train of the vehicle which concerns on embodiment. It is a skeleton figure which shows the structure of an automatic transmission. It is a graph which shows the engagement state of the clutch and brake for each gear stage in an automatic transmission. It is a schematic block diagram of the part which controls a friction engagement element in a hydraulic control circuit. It is a flowchart figure which shows an example of ND control routine. FIG. 5 is a view corresponding to FIG. 3 schematically showing a friction engagement element or the like that may cause a failure when a failure determination is made during traveling at the third gear. It is a flowchart figure which shows an example of the shift control routine at the time of a failure.

  Hereinafter, an embodiment in which the control device of the present invention is applied to an FF (front engine / front drive) vehicle will be described. First, FIG. 1 schematically shows an overall configuration of a power train mounted on a vehicle. The power train includes an engine 1, a torque converter 2, an automatic transmission 3, and the like, and an output from the automatic transmission 3 is transmitted to, for example, a driving wheel 6 that is a front wheel of the vehicle via a differential device 5 or the like. It has come to be.

  As an example, the engine 1 is a multi-cylinder gasoline engine, and an output shaft of the engine 1 is connected to a torque converter 2. As is well known, the engine 1 is equipped with an injector 11 that can adjust the fuel injection amount, an igniter 12 that can adjust the ignition timing of the spark plug, and an electric throttle valve 13 that can adjust the intake air amount. In addition, a crank angle sensor 101 (see FIG. 2) is provided for detecting the rotation speed (engine rotation speed) of the crankshaft 1a.

  As shown in FIG. 2, the torque converter 2 includes an input-side pump impeller 21, an output-side turbine runner 22, and a stator 23 that develops a torque amplification function, and is provided between the pump impeller 21 and the turbine runner 22. It is a publicly known one that transmits power through a fluid. The torque converter 2 is provided with a lock-up clutch 24 that connects the turbine runner 22 on the output side to the input side, and also detects the rotation speed (turbine rotation speed) of the turbine shaft 2a that is the output shaft. A sensor 102 is also provided.

-Automatic transmission-
The automatic transmission 3 comprises a known stepped gear transmission mechanism, and its input shaft 3a is connected to the turbine shaft 2a so that rotation from the torque converter 2 is inputted. The rotation input in this way is shifted as described below and transmitted from the output shaft 3b to the differential device 5 through the output gear 3c. The rotation speed of the output shaft 3 b (output shaft rotation speed No) is detected by the output shaft rotation speed sensor 103.

  As shown in FIG. 2, the automatic transmission 3 includes a first transmission unit (front planetary) 31, a second planetary gear unit 32a, and a third planetary gear unit 32b. The first planetary gear unit 31a is a main component. And the second transmission unit (rear planetary) 32, the first to fourth clutches C1 to C4, the first and second brakes B1 and B2, and the like.

  The first planetary gear device 31a constituting the first transmission unit 31 is a double pinion type planetary gear mechanism, and supports a sun gear S1, a plurality of pairs of pinion gears P1 meshing with each other, and the pinion gears P1 so as to be able to rotate and revolve. Planetary carrier CA1 and ring gear R1 meshing with sun gear S1 via pinion gear P1.

  The planetary carrier CA1 is coupled to the input shaft 3a and rotates integrally with the input shaft 3a. The sun gear S1 is fixed to the transmission case 30 and cannot rotate. The ring gear R1 functions as an intermediate output member, is decelerated with respect to the input shaft 3a, and transmits the decelerated rotation to the second transmission unit 32.

  The second planetary gear unit 32a constituting the second transmission unit 32 is a single pinion type planetary gear mechanism, which is a sun gear S2, a pinion gear P2, and a planetary carrier RCA that supports the pinion gear P2 so as to be capable of rotating and revolving. And a ring gear RR that meshes with the sun gear S2 via the pinion gear P2.

  The third planetary gear device 32b constituting the second transmission unit 32 is a double pinion type planetary gear mechanism, and includes a sun gear S3, a plurality of pairs of pinion gears P2 and P3 meshing with each other, and the pinion gears P2 and P3. A planetary carrier RCA that supports rotation and revolution is provided, and a ring gear RR that meshes with the sun gear S3 via pinion gears P2 and P3. The planetary carrier RCA and the ring gear RR are shared by the second planetary gear device 32a and the third planetary gear device 32b.

  The sun gear S2 is selectively connected to the transmission case 30 by the first brake B1, is selectively connected to the ring gear R1 via the third clutch C3, and is connected to the planetary carrier CA1 via the fourth clutch C4. Selectively linked. Sun gear S3 is selectively coupled to ring gear R1 via first clutch C1. The planetary carrier RCA is selectively coupled to the transmission case 30 by the second brake B2. The planetary carrier RCA is selectively coupled to the input shaft 3a via the second clutch C2. The ring gear RR is connected to the output shaft 3b and rotates integrally.

  The four clutches C1 to C4 and the two brakes B1 and B2 are friction engagement elements that are frictionally engaged by hydraulic actuators Ac1 to Ac6 (see FIG. 4). By selectively engaging these frictional engagement elements, the forward 8-speed gear stage (the first-speed gear stage to the eighth-speed gear stage, which is a shift stage) and the reverse gear stage (shift stage). Reverse gear stage) is established.

  FIG. 3 is an engagement table showing an engaged state or a released state of the first clutch C1 to the fourth clutch C4, the first brake B1, and the second brake B2 for each gear stage. ", And a blank indicates" released state ". As shown in FIG. 3, in the automatic transmission 3, the gear ratio (the rotational speed Nin of the input shaft 3a / the rotational speed No of the output shaft 3b) is changed by engaging the first clutch C1 and the second brake B2. The largest first gear (1st) is established, and the engagement of the first clutch C1 and the first brake B1 establishes the second gear (2nd).

  Further, the engagement of the first clutch C1 and the third clutch C3 changes the third speed gear stage (3rd), and the engagement of the first clutch C1 and the fourth clutch C4 changes the fourth speed gear stage (4th) to the first clutch C1. The fifth gear (5th) is established by engagement of the second clutch C2. Further, the sixth gear (6th) is brought about by engagement of the second clutch C2 and the fourth clutch C4, and the seventh gear (7th) is brought about by engagement of the second clutch C2 and the third clutch C3. The eighth gear (8th) is established by the engagement of the first brake B1.

  If the travel control range of the automatic transmission 3 is the drive range (D range), one of the first gear to the eighth gear is formed, while if the reverse drive range (R range), As shown in FIG. 3, the third clutch C3 and the second brake B2 are engaged to form a reverse speed (Rev). Further, in the neutral range (N range) and the parking range (P range) in which power transmission is interrupted, all frictional variant elements other than the second brake B2, that is, the first clutch C1 to the fourth clutch C4 and the first brake B1. To release. In the P range, for example, the rotation of the output shaft 3b is mechanically restricted by a parking lock mechanism (not shown).

-Hydraulic control circuit-
Engagement and disengagement of the plurality of friction engagement elements (clutches C1 to C4 and brakes B1 and B2) as described above are controlled by the hydraulic control circuit 4. FIG. 4 shows an example of a circuit diagram of linear solenoid valves SL1 to SL6 that supply control oil pressure to the hydraulic actuators Ac1 to Ac6 of the friction engagement elements in the hydraulic control circuit 4. Note that a circuit for controlling the torque converter 2 and the like is not shown.

  The linear solenoid valves SL1 to SL6 have basically the same configuration, and are individually excited and de-energized by the ECU 100 to regulate the line hydraulic pressure PL and supply it directly to the hydraulic actuators Ac1 to Ac6. Thereby, the engagement hydraulic pressure of each friction engagement element is individually adjusted, and the gear stage is established as shown in the engagement table of FIG. When the gear stage is switched, a clutch-to-clutch shift is performed by changing the grip between the disengagement side frictional engagement element and the engagement side frictional engagement element.

  The release-side friction engagement element is a release-side friction engagement element when the gear is switched. For example, in the engagement table of FIG. The clutch C1 corresponds to the 5th speed → 6th speed upshift. Similarly, the engagement-side friction engagement element is a hydraulic friction engagement element on the engagement side. In the 3rd speed → 4th speed upshift and the 5th speed → 6th speed upshift, the clutch C4 is used. Corresponds.

-ECU-
The ECU 100 is a known computer device that includes a CPU, a ROM, a RAM, a backup RAM, a timer, and the like. The ROM stores various control programs, a map to be referred to when executing them, and the like. The CPU executes arithmetic processing by a control program or the like stored in the ROM. The RAM is a memory for temporarily storing calculation results from the CPU, data inputted from each sensor, and the backup RAM is a non-volatile memory for storing data to be saved when the engine 1 is stopped. It is.

  As shown in FIG. 1, in addition to the crank angle sensor 101, the turbine rotational speed sensor 102, and the output shaft rotational speed sensor 103, the ECU 100 includes an accelerator opening that detects an operation amount (accelerator opening) of an accelerator pedal (not shown). A degree sensor 104, a shift position sensor 105 that detects a position (shift position) of a shift lever (not shown), and the like are connected. An injector 11 for adjusting the state of the engine 1, an igniter 12, an electric throttle valve 13, and the like are also connected to the ECU 100.

  The ECU 100 performs various control calculations based on signals input from the various sensors (including switches) and the like. The fuel injection amount by the injector 11, the ignition timing of the ignition plug by the igniter 12, and the throttle valve 13. The operating state of the engine 1, for example, the engine torque or the like is controlled by controlling the opening degree (that is, the intake air amount).

  Further, the ECU 100 controls the hydraulic actuators Ac1 to Ac6 of the hydraulic control circuit 4 according to signals from the accelerator opening sensor 104 and the shift position sensor 105 and the traveling state of the vehicle, and the automatic transmission 3 of the automatic transmission 3 as described above. A plurality of friction engagement elements are engaged and released to establish an appropriate gear (1st gear to 8th gear, reverse gear). Although one ECU 100 is shown in FIG. 1, this may be divided into a plurality of ECUs for engine control and transmission control.

  In the present embodiment, for example, when the shift lever is operated to the drive position and the traveling control range of the automatic transmission 3 is the D range, the shift map (not shown) is referred to based on the traveling state of the vehicle, for example. Thus, a suitable gear stage is selected. The shift map is stored in the ROM of the ECU 100 in the form of a shift diagram using the vehicle speed and the accelerator opening (or the throttle opening) as parameters.

  Specifically, the ECU 100 calculates the vehicle speed based on a signal from the output shaft rotational speed sensor 103 (output shaft rotational speed No), and shifts based on the vehicle speed and a signal from the accelerator opening sensor 104 (accelerator opening). The target gear is determined with reference to the map. Further, based on the signal from the turbine rotational speed sensor 102 (the turbine rotational speed coincides with the rotational speed of the input shaft 3a, hereinafter referred to as the input shaft rotational speed Nin) and the output shaft rotational speed No, the current gear Determine the stage.

  If the current gear stage and the target gear stage are different from each other, the gear change is performed as described below to switch the gear stage. For example, if the current gear is the third gear and the vehicle speed increases and crosses the 3 → 4 upshift line in the shift map, the target gear calculated from the shift map is the fourth gear. A control signal (hydraulic command value to the linear solenoid valves SL1 to SL6) for switching to the fourth gear is output to the hydraulic control circuit 4 of the automatic transmission 3 to perform an upshift from the third speed to the fourth speed. .

  Also, for example, if the accelerator pedal is depressed when the current gear stage is the fifth speed gear stage and crosses the 5 → 4 downshift line in the shift diagram, the target gear stage calculated from the shift map is the fourth speed. Therefore, a control signal for switching to the 4th gear stage is output to the hydraulic control circuit 4 of the automatic transmission 3 to downshift from the 5th gear to the 4th gear. Although detailed description is omitted, in the present embodiment, the shift control of the clutch-to-clutch is performed using a shift model represented by the gear train motion equation of the automatic transmission 3.

  That is, in general, in clutch-to-clutch shift control, the required input torque of the input shaft 3a is handled by the engagement side and release side frictional engagement elements, and the engagement side and release side according to the degree of progress of the shift. The torque sharing of the friction engagement element is changed. Therefore, a suitable torque sharing ratio that changes in accordance with the progress of such shift is set in advance for each shift pattern (for example, power-on upshift, power-off upshift, etc.) by, for example, experiments and simulations, and the ROM of ECU 100 Remember me.

  Then, the ECU 100 reads out the torque sharing rate corresponding to the degree of progress during the shift control, and uses the shift model to request the required input torque of the input shaft 3a, the request for the engagement-side and release-side friction engagement elements. Calculate the torque capacity. The ECU 100 controls the engine torque according to the degree of progress of the shift so that the calculated required input torque is obtained. Further, the engagement side and release side frictional engagement elements are controlled (hydraulic pressure control by the hydraulic pressure control circuit 4) according to the degree of progress of the shift so that the calculated required torque capacity is obtained.

-ND control routine-
By the way, in the present embodiment, for example, when the driver operates the shift lever from the neutral position to the drive position (hereinafter referred to as ND operation) in order to start a stopped vehicle, the travel control range of the automatic transmission 3 is set. Becomes the D range and the target gear stage becomes the first gear stage. Therefore, as shown in FIG. 3, the first clutch C1 is gradually engaged while the second brake B2 is engaged.

  On the other hand, if, for example, the shift lever is accidentally operated to the neutral position while the vehicle is running, and then the ND operation is performed, the target gear is set to a higher gear (second speed to 8 speed gear stage). In this case, two frictional engagement elements are engaged as shown in FIG. 3, so that one frictional engagement element is preferentially engaged, and the engine 1 is ND control is performed to suppress the shift shock by performing torque down control.

  FIG. 5 specifically shows an example of the ND control routine according to the present embodiment. This routine is executed, for example, for a predetermined time while the vehicle is traveling (when the vehicle speed exceeds a stop determination value close to zero). It is executed repeatedly at intervals. First, in step S101 after the start, it is determined whether or not an ND operation has been performed based on a signal from the shift position sensor 105. If the determination is negative (NO), the process ends (end). If the -D operation is performed and an affirmative determination is made (YES), the process proceeds to step S102.

  In step S102, the target gear is calculated with reference to the shift map based on the vehicle speed and the accelerator opening as described above. Then, in step S103, it is determined whether or not the calculated target gear is greater than or equal to the second speed. If the determination is negative (NO), that is, if it is the first speed, the process proceeds to step S109, which will be described later. (YES), the two friction engagement elements are engaged as described above.

  Therefore, in step S104, it is determined whether or not it is necessary to perform torque-down control of the engine 1 in order to engage the two friction engagement elements without a large shock. That is, it is determined whether or not the accelerator is on based on the signal from the accelerator opening sensor 104. If, for example, the accelerator opening is equal to or greater than a preset threshold and the accelerator is on (YES), the process proceeds to step S105. Then, torque down control of the engine 1 is executed, and the process proceeds to step S106.

  In addition, as torque reduction control of the engine 1, for example, the opening degree of the throttle valve 13 may be made smaller than a normal value corresponding to the accelerator opening degree to reduce the intake air amount. Alternatively or in addition to this, the fuel injection amount by the injector 11 can be reduced, or the ignition timing by the igniter 12 can be retarded.

  On the other hand, for example, if the accelerator opening is less than a preset threshold value and a negative determination is made in step S104 (NO), the torque reduction control is not performed and the process proceeds to step S106 to form two frictional engagements that form the target gear stage. Any one of the engagement elements is engaged early. That is, the hydraulic pressure command value output to the linear solenoid valves Ac1 to Ac6 (see FIG. 4) corresponding to the friction engagement element is increased early in a predetermined manner.

  As a predetermined mode, a time until the maximum pressure is reached after an increase in the hydraulic pressure command value is set in advance, and so-called quick apply control, low-pressure standby control, and sweep control are performed within this time. You can do it. In this case, the time for increasing the hydraulic pressure is set to a certain length or longer so that the engagement shock can be reduced.

  Subsequently, in step S107, it is determined whether or not a predetermined condition for starting the engagement of the other friction engagement element among the two friction engagement elements forming the target gear stage is satisfied. As this predetermined condition, for example, the hydraulic pressure command value of the one friction engagement element exceeds a preset value, or the elapsed time after the increase of the hydraulic pressure command value exceeds a preset time. And so on.

  If the predetermined condition is not satisfied, a negative determination is made (NO), and the process of step S107 is repeated. In other words, it waits until a predetermined condition is satisfied, and if the predetermined condition is satisfied and an affirmative determination is made in step S107 (YES), the process proceeds to step S108, and the other friction engagement element is gradually engaged. That is, the hydraulic pressure command value output to the linear solenoid valves Ac1 to Ac6 corresponding to the friction engagement element is gradually increased according to the required torque capacity, and then the routine is ended (END).

  That is, when two friction engagement elements are engaged according to the ND operation, the shock is suppressed by preferentially engaging one of them. On the other hand, the target gear stage calculated in step S102 is the first gear stage. In step S109, where a negative determination is made (NO) in step S103, the output is output to the linear solenoid valve Ac1 of the first clutch C1. The hydraulic pressure command value is gradually increased according to the required torque capacity, and then the routine is ended (END).

  By executing the ND control routine of FIG. 5, the ECU 100 cooperates with the torque-down control of the engine 1 when the travel control range of the automatic transmission 3 is switched from the N range to the D range while the vehicle is traveling. On the other hand, the ND control means for performing the shift control to the target gear stage is configured. Thus, in this embodiment, the ND control means is in the form of a software program.

-Shift control during failure-
As described above, in the automatic transmission 3 that is in the D range during the traveling of the vehicle, any of the plurality of friction engagement elements forming the selected gear stage becomes incompletely engaged, and the engine 1 Torque may not be sufficiently transmitted to the output side. As a result, the rotation of the input shaft 3a of the automatic transmission 3 (input shaft rotation speed Nin), that is, the turbine rotation speed detected by the turbine rotation speed sensor 102 suddenly increases (so-called “turbine blowing”). .

  Therefore, in the present embodiment, it is determined that the “turbine blowing” has occurred, and it is determined that there is a risk of failure of engagement between the two friction engagement elements forming the gear stage at that time, The two friction engagement elements are shifted to another gear stage in which neither of them is engaged. Specifically, as schematically shown by a thick frame F in FIG. 6, for example, when “turbine blowing” occurs in the third gear, the linear solenoid valve corresponding to the first clutch C1 or the third clutch C3. A failure of SL1 and SL3 is considered.

  That is, as shown in FIG. 6 with hatching, since both the first clutch C1 and the third clutch C3 may fail, both the first and third clutches C1 and C3 are engaged. In the example shown in the figure, the 6th gear stage or the 8th gear stage is set as a new target gear stage, that is, the target gear stage of the transition destination.

  However, in the gear shifting in such a state where the frictional engagement element is failing, unlike the normal state, a large shock may occur. For example, when releasing the third clutch C3 in the above example, if the first clutch C1 is poorly engaged, the input shaft rotational speed Nin does not converge to the synchronous rotational speed after the end of the shift. This is because so-called backup engagement is performed and the fourth clutch C4 is suddenly engaged.

  Focusing on this point, in the present embodiment, when "turbine blowing" occurs as described above, first, the travel control range is switched to the N range and the friction engagement element is once released, The above-described ND control routine is executed to shift to another gear stage. Hereinafter, referring to the flowchart of FIG. 7, taking as an example a case where either one of the linear solenoid valves SL1 and SL3 fails in a state where the third gear is established (the first clutch C1 and the third clutch C3 are engaged). This will be described in detail.

  The illustrated failure time control routine is repeatedly executed, for example, at predetermined time intervals while the vehicle is running. First, in step S201 after the start, it is determined whether turbine blow has occurred. This is, for example, when the signal (input shaft rotational speed Nin) of the turbine rotational speed sensor 102 suddenly rises above a preset threshold with respect to the signal of the output shaft rotational speed sensor 103 (rotational speed No of the output shaft 3b). What is necessary is just to determine with turbine blowing having generate | occur | produced.

  If a negative determination is made that turbine blowing has not occurred (NO), the routine is once terminated (END). On the other hand, if an affirmative determination is made that turbine blow has occurred (YES), the routine proceeds to step S202, where another gear stage in which neither the first or third clutch C1, C3 that may fail is engaged is engaged. Determine the gear stage. At this time, it is preferable that the sixth gear is the closest among the higher gears than the current gear (the third gear).

  Subsequently, in step S203, the travel control range of the automatic transmission 3 is once switched to the N range. As a result, the frictional engagement elements (the first clutch C1 to the fourth clutch C4 and the first brake B1) that can be engaged in the D range are all released, so that the first or third clutch C1, C3 has failed. However, no problem occurs. Then, in step S204, the above-described ND control routine is executed and the routine is terminated (END).

  In other words, the second and fourth clutches C2 and C4 that do not cause a failure are engaged to form a sixth gear, and at this time, as described above with reference to FIG. The engagement element (for example, the second clutch C2) is preferentially engaged with the other friction engagement element (for example, the fourth clutch C4), and torque reduction control of the engine 1 is also performed as necessary. Is suppressed.

  By executing step S201 of the flow shown in FIG. 7, the ECU 100 causes the frictional engagement element being engaged to fail when the input shaft rotation of the automatic transmission 3 is greatly increased by a predetermined amount or more during traveling of the vehicle. Fail determination means for determining that there is a risk of failure, and by executing steps S202 to S204, the gear stage in which the frictional engagement element that is likely to fail is released is set as the target gear stage, After switching to the N range, the failure time control means is configured to switch to the D range again and execute the ND control routine.

  Therefore, according to the control device for a vehicle according to the present embodiment, when it is determined that there is a possibility that a “turbine blowing” occurs during the traveling of the vehicle and the friction engagement element is in a failure of engagement, the failure is detected. Since another gear stage that does not have the risk of being set is set as the target gear stage of the transition destination and once switched to the N range, it is made to transition to the other gear stage by ND control, so a big shock is generated It is possible to switch to another gear stage without making it. As a result, the vehicle can be evacuated.

-Other embodiments-
The above description of the embodiment is merely an example, and is not intended to limit the configuration or use of the present invention. For example, in the above-described embodiment, the case where the present invention is applied to the FF vehicle equipped with the automatic transmission 3 with the forward 8 speed is described as an example. However, the present invention is not limited to this, for example, the forward 7 speed or less and the forward The present invention can also be applied to a vehicle equipped with an automatic transmission of 9 speeds or more, an FR (front engine / rear drive) type vehicle, or a four-wheel drive vehicle.

  In the above-described embodiment, the case where the present invention is applied to a vehicle equipped with a gasoline engine is described as an example. However, the present invention is not limited to this, and the present invention is not limited to this, for example, other spark ignition such as an alcohol engine or a gas engine. It can also be applied to vehicles equipped with an engine. Further, the present invention is not limited to a vehicle equipped with only an engine as a driving force source, and can be applied to, for example, a hybrid vehicle (a vehicle equipped with an engine and an electric motor as a driving force source).

  The present invention is particularly effective when applied to a passenger car or the like because it can be switched to another gear stage without generating a large shock when a failure of a friction engagement element is determined in an automatic transmission of a vehicle. .

1 Engine 3 Stepped automatic transmission C1-C4, B1, B2 Clutch, brake (friction engagement element)
100 ECU (ND control means, failure determination means, failure time control means)

Claims (1)

A control device for a vehicle equipped with an engine and a stepped automatic transmission,
ND control means for performing shift control to the target gear stage in cooperation with torque reduction control of the engine when the travel control range of the automatic transmission is switched from the N range to the D range during travel of the vehicle. With
Fail determination means for determining that there is a risk of failure in the engaged frictional engagement element due to the input shaft rotation of the automatic transmission blowing up more than a predetermined amount during traveling of the vehicle in the D range;
The shift speed at which the frictional engagement element determined to be a failure is released is set as the target shift speed, the travel control range is once switched to the N range, and then switched to the D range again. A vehicle control apparatus comprising: a fail-time control unit that executes shift control by the D control unit.

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