JP4675039B2 - Vehicle driving force control device - Google Patents

Description

  The present invention relates to a vehicular driving force control device, and more particularly to a vehicular driving force control device that can reliably perform engagement or half-engagement of a lockup clutch when the vehicle is in a driven state.

  As shown in FIG. 3, a torque converter 21 used as a fluid coupling of an automatic transmission of a vehicle includes a lockup clutch 31 between a pump impeller (engine side) 24 and a turbine runner (transmission side) 26. A so-called mechanical clutch is provided. When the vehicle speed exceeds a predetermined vehicle speed, the lockup clutch 31 is pressed against the front cover 35, and the input shaft (front cover 35) and the output shaft (turbine runner 26) are fastened by the frictional force generated at this time. By transmitting power directly, the transmission efficiency of the automatic transmission is increased and fuel efficiency is improved.

  In the released state where the lockup is not performed, the pressure supplied from the oil pump of the hydraulic control circuit 34 is the pressure on both sides of the lockup piston 36, that is, the pressure in the release side oil chamber 33 and the pressure in the engagement side oil chamber 32. Are almost the same.

  When the lockup control mechanism is activated, the oil supplied from the oil pump causes the pressure in the engagement side oil chamber 32 to be higher than the pressure in the release side oil chamber 33, and the lockup clutch 31 (clutch fading) and the front cover. 35 is connected (engaged) and locked up.

JP-A-10-184896 JP 7-81460 A

  By the way, the lock-up clutch has a property that it is difficult to be engaged when the vehicle is in a driven state (power-off state). Here, the driven state of the vehicle refers to a state in which torque is transmitted from the driving wheels toward the engine (the engine generates negative torque).

  As described above, the lock-up clutch is engaged / released by the balance of hydraulic pressures acting on both sides thereof. In FIG. 11, when the vehicle is in a driving state (power-on state), the flow in the torus T of the torque converter 21 is as indicated by an arrow Y1, and the flow velocity between the front cover 35 and the lockup piston 36 is increased (pressure). Is equivalent to the balance of the force of pressing the lockup clutch 31 against the front cover 35).

  On the other hand, in the driven state of the vehicle, the flow in the torus T is reversed from the direction indicated by the arrow Y1 in FIG. 11 (the turbine 26 drives the pump 24), and the flow velocity between the front cover 35 and the lockup piston 36 is increased. Since it cannot be obtained sufficiently (equivalent to a reduction in the force of pressing the lockup clutch 31 against the front cover 35), it becomes difficult to engage the lockup clutch 31.

  It is desired that the lock-up clutch is reliably engaged when the vehicle is in a driven state. When the lockup clutch is engaged in the driven state of the vehicle, the rotational torque of the driving wheels is directly transmitted to the engine without passing through the torque converter, thereby improving the engine speed. This is because fuel cut is realized by the increase in the engine speed and contributes to improvement in fuel consumption.

  Further, if the automatic transmission is shifted when the vehicle is in a driven state, it may be difficult to engage the lockup clutch. For example, when an upshift (power-off upshift) is performed due to the driven state, if the shift is delayed, it may be difficult to engage the lockup clutch. That is, in general, in an automatic transmission, a predetermined low speed stage is set in advance when the lockup clutch is released regardless of the throttle valve opening and the vehicle speed, but from the low speed stage set as such, When the shift is delayed when the upshift is performed at the high speed stage where the lockup clutch can be engaged as the accelerator is turned off, it becomes difficult to engage the lockup clutch. The reason will be described below.

  When the engine speed is upshifted, the torque acting on the torque converter increases because the engine speed is reduced, and the engagement of the lockup clutch becomes difficult accordingly. This is the first reason.

  In addition, due to the relationship between the shift shock associated with the shift and the shock associated with the engagement of the lock-up clutch, the lock-up clutch is engaged after the shift operation is completed. This leads to a delay in engagement of the lockup clutch. In addition, as a countermeasure against shock associated with the engagement of the lock-up clutch, the lock-up clutch is not engaged instantaneously when the accelerator is off, but the engagement operation is performed over a predetermined time. Engagement time is delayed. Here, in general, as a countermeasure against a shock when the accelerator is off, control is performed so that the driving force remains for a while even when the accelerator is turned off (a sudden movement change is buffered). If the engagement of the lockup clutch is delayed until the time when the driven state is reached, the engagement of the lockup clutch becomes difficult. This is the second reason.

  By the way, as described above, since it is difficult to engage the lockup clutch in the driven state, the following shift stage selection control (setting of the shift map) is performed regarding the downshift accompanying the accelerator off. There was a case.

  Originally, a situation is considered in which it is better to select a predetermined high speed stage (for example, the fourth speed) in terms of fuel consumption according to the traveling conditions such as the vehicle speed. Here, it is assumed that the high gear (fourth gear in this example) is a gear that is set in advance when the lockup clutch is released. In this case, when the downshift accompanying the accelerator off is performed when the accelerator is off, the reason is that the lockup clutch is difficult to engage in the driven state, or the lockup clutch is used in the downshift in the driven state. The lock-up clutch is not engaged (or half-engaged) due to the effect of the force on the release side acting on the gear, and the lock-up clutch is engaged even after shifting to a shift stage after downshifting (for example, third gear). The disengaged state remains. As a result, the effect of increasing the engine speed due to the engagement of the lock-up clutch in the driven state cannot be obtained, and the engine speed decreases. As a result, the fuel cut effect cannot be obtained sufficiently.

  Therefore, in the past, focusing on the fact that the effect of fuel cut after shifting is greater than the improvement in fuel efficiency by selecting the high speed before shifting (fourth speed in this example), the shifting stage when the accelerator is off (before downshifting) When the lock-up clutch is released due to the accelerator being off, it is difficult to upshift to a preset gear position (fourth speed in this example) (a gear stage in which the lockup clutch can be engaged (three in this example)). In some cases, the up-point of the shift map is set on the upper side so that (speed) can be easily selected. As described above, since the gear position (low speed gear) to which the lockup clutch is engaged is easily selected, the gear position to which the same lockup clutch is engaged even after the driven state associated with the accelerator off is achieved. Then, the lockup clutch is maintained in the engaged state to obtain a fuel cut effect.

  If the difficulty of engaging the lock-up clutch in the driven state is resolved compared to the conventional shift stage selection control as described above, the shift stage when the accelerator is off is optimal in terms of fuel consumption from the driving conditions. The above-described selection of the high speed stage (fourth speed in this example) eliminates the problem and helps improve fuel efficiency (elimination of fuel consumption loss due to use of the low speed stage).

  In Patent Document 1, slip control of the lockup clutch is performed by controlling the ISC valve when the lockup clutch is in the released state and the accelerator is turned off, and then the lockup clutch is controlled. A technique is disclosed in which full engagement is performed. However, there is a problem that even if the ISC control valve is opened, if it is in a driven state, the shift to the slip control is not successful. Also, if the ISC control valve is opened to such an extent that the shift to the slip control can be realized, the vehicle is in a driving state or the deceleration acceleration corresponding to the accelerator off cannot be obtained despite the accelerator off state. The driving feeling may get worse. In addition, opening the ISC control valve causes a torque fluctuation during deceleration, resulting in a problem that travel feeling is lowered.

  An object of the present invention is to provide a vehicle driving force control device that can reliably perform engagement or half-engagement of a lockup clutch when the vehicle is in a driven state.

The vehicle driving force control apparatus according to the present invention includes an engine output control unit that controls output of an engine, a lock-up clutch provided between the engine and driving wheels, and the driving wheel provided between the driving wheels. Driving force reduction means capable of reducing the driving force transmitted to the wheel, and when the vehicle is in a driven state or when the vehicle is in a transition from a driving state to a driven state, the lock When the up clutch is engaged or semi-engaged, the engine output control unit increases the opening of the electronic throttle, compared to when the lock-up clutch is not engaged or semi-engaged, and the output of the engine by injecting the fuel at the fuel injection valve is controlled to increase, the drive force reducing means, in the engine output control unit that performs as an output of the engine is increased It is characterized in that the work movement of Ru reduce the driving force control to be transmitted to the drive wheel so as to cancel the increase in the driving force of the driving wheel according to the control at the same time.

  In the present invention, when the vehicle is in a driven state or when the vehicle is in a transition from a driving state to a driven state and the lockup clutch is engaged or semi-engaged. The engine output is increased and the driving force transmitted to the drive wheels is reduced as compared with the normal case. As a result, the power transmission path from the engine to the vehicle is in a driving state, so that engagement or half-engagement of the lockup clutch is reliably executed. In the present invention, the engine output control unit can control the engine output to be larger than normal by increasing the opening of the electronic control throttle as compared to normal.

  In the vehicle driving force control apparatus according to the present invention, the driving force reducing means is at least one of an engagement element of a transmission, a brake, and a motor generator.

  In the vehicle driving force control apparatus according to the present invention, a first detection unit that detects a rotation state of a rotating body between the lock-up clutch and the driving wheel, and a second detection that detects a rotation state of the engine. And the control of the engine output control unit and the operation of the driving force reduction means are terminated based on the detection result of the rotation state of the rotating body and the detection result of the rotation state of the engine. Yes. Based on both detection results, it is detected that the lock-up clutch is engaged or semi-engaged, and the engine output is detected when the lock-up clutch is engaged or semi-engaged. The control by the control unit and the operation of the driving force reducing means can be finished. In this case, the end mode can gradually decrease the control amount or the operation amount so as not to give the driver a sense of incongruity.

  The present invention relates to an engine, a lock-up clutch, and means (an engagement element of a transmission, a brake, and a motor) that are between the lock-up clutch and the drive wheel and that can reduce the drive force transmitted to the drive wheel. In a vehicle driving force control apparatus equipped with at least one of generators), the lockup clutch is engaged or semi-engaged when the vehicle is in a driven state or during a transition from a driving state to a driven state. It is determined whether or not it is necessary, and as a result of the determination, it is necessary to engage or semi-engage the lockup clutch when the vehicle is in a driven state or during a transition from a driving state to a driven state. When it is determined, the engine output is set to a higher level than in a normal driven state or a transition from the driven state to the driven state (the electronic throttle is opened). A braking force control for operating an engine output control and operating a means between the lock-up clutch and the driving wheel and capable of reducing a driving force transmitted to the driving wheel. It is characterized by doing.

  In the present invention, based on the rotation state of the rotating body between the lockup clutch and the drive wheel and the rotation state of the engine, the engagement or half engagement state of the lockup clutch is detected, The engine output control and the braking force control are ended when the lockup clutch is engaged or semi-engaged.

  According to the vehicle driving force control device of the present invention, when the vehicle is in a driven state, engagement or half-engagement of the lockup clutch can be reliably performed.

  Hereinafter, an embodiment of a vehicle driving force control device of the present invention will be described in detail with reference to the drawings.

(First embodiment)
The purpose of this embodiment is to reliably engage the lockup clutch in the driven state (power-off state).

  The embodiment includes a transmission including a lockup clutch, a motor generator device or a brake and a control device disposed on the downstream side of the lockup clutch, and output control of a power source (engine) upstream of the lockup clutch. In the transient state from the driven state or the driving state (power-on state) to the driven state, the electronic control throttle opening is made larger than the electronic control throttle opening corresponding to the normal accelerator opening. , Motor generator regenerative braking, braking operation or braking force due to engagement of engagement elements of the transmission, to enable engagement of the lockup clutch without significantly changing the driving force characteristics in the tire It is.

  FIG. 3 is a skeleton diagram of the vehicle drive device. The power of the engine 20 is transmitted to the drive wheel via a torque converter (fluid coupling) 21 with a lock-up clutch 21, a stepped automatic transmission 10 composed of three sets of planetary gear units, a differential gear device (not shown), and the like. Is done.

  The torque converter 21 is a turbine (turbine runner) fixed to a pump (pump impeller) 24 connected to the crankshaft 23 of the engine 20 and an input shaft 25 of the automatic transmission 10 and opposed to the pump 24 via oil. 26, a stator 29 fixed to the housing 28 via a one-way clutch 27, and a lock-up clutch 31 connected to the input shaft 25 via a damper 30.

  In the torque converter 21, an engagement side oil chamber 32 is formed on the right side in the drawing from the lockup piston 36, and a release side oil chamber 33 is formed on the left side in the drawing from the lockup piston 36. Yes.

  When the hydraulic pressure in the disengagement side oil chamber 33 is higher than the engagement side oil chamber 32 of the torque converter 21 by the oil pressure control device 34, the lockup clutch 31 is released and the oil is passed from the pump 24 to the turbine 26. Torque is transmitted.

  On the other hand, when the hydraulic pressure in the engagement side oil chamber 32 is higher than that in the release side oil chamber 33, the lockup clutch 31 is pressed against the front cover 35 to be engaged, and the input / output member of the torque converter 21, that is, the crank The shaft 23 and the input shaft 25 are mechanically directly connected. Further, when the hydraulic pressures in the release side oil chamber 33 and the engagement side oil chamber 32 are maintained in an appropriate balance, the lockup clutch 31 enters a slip state, and a power transmission state intermediate between release and engagement is formed.

  The automatic transmission 10 includes a first transmission unit 320 that switches between two stages of high and low, and a second transmission unit 340 that can switch between a reverse transmission stage and four forward stages. The first speed change unit 320 is supported by the sun gear S0, the ring gear R0, and the carrier K0 so as to be rotatable, and the HL planetary gear device 360 including the planetary gear P0 meshed with the sun gear S0 and the ring gear R0, and the sun gear S0 and the carrier. A clutch C0 and a one-way clutch F0 provided between K0 and a brake B0 provided between the sun gear S0 and the housing 380 are provided.

  The second transmission unit 340 includes a first planetary gear device 400 including a planetary gear P1 that is rotatably supported by the sun gear S1, the ring gear R1, and the carrier K1 and meshed with the sun gear S1 and the ring gear R1, and the sun gear S2. A second planetary gear device 420 comprising a planetary gear P2 that is rotatably supported by the ring gear R2 and the carrier K2 and meshed with the sun gear S2 and the ring gear R2, and the sun gear S3, the ring gear R3, and the carrier K3 is rotatable. And a third planetary gear unit 440 including a planetary gear P3 supported and meshed with the sun gear S3 and the ring gear R3.

  The sun gear S1 and the sun gear S2 are integrally connected to each other, the ring gear R1, the carrier K2, and the carrier K3 are integrally connected, and the carrier K3 is connected to the output shaft 120c. The ring gear R2 is integrally connected to the sun gear S3 and the intermediate shaft 48. A clutch C1 is provided between the ring gear R0 and the intermediate shaft 48, and a clutch C2 is provided between the sun gear S1 and the sun gear S2 and the ring gear R0. The housing 38 is provided with a band-type brake B1 for stopping the rotation of the sun gear S1 and the sun gear S2. A one-way clutch F1 and a brake B2 are provided in series between the sun gear S1 and the sun gear S2 and the housing 38. The one-way clutch F <b> 1 is engaged when the sun gear S <b> 1 and the sun gear S <b> 2 try to rotate in the opposite direction to the input shaft 22.

  A brake B3 is provided between the carrier K1 and the housing 38, and a brake B4 and a one-way clutch F2 are provided in parallel between the ring gear R3 and the housing 38. The one-way clutch F2 is engaged when the ring gear R3 tries to rotate in the reverse direction.

  In the automatic transmission 10 configured as described above, for example, according to the operation table shown in FIG. 4, it is switched to one of the reverse gears and the five forward gears (1st to 5th) with different gear ratios. In FIG. 4, “◯” represents engagement, a blank represents release, “解放” represents engagement during engine braking, and “Δ” represents engagement not involved in power transmission. The clutches C0 to C2 and the brakes B0 to B4 are all hydraulic friction engagement devices that are engaged by a hydraulic actuator.

As shown in FIG. 5, an intake pipe of the engine 20 of the vehicle is provided with an electronic throttle 5 2. An accelerator opening sensor 51 detects an accelerator opening that changes according to the operation of the accelerator pedal 50. The control device 100 outputs a throttle valve control command SG1 to the throttle opening control device 53 based on the accelerator opening detected by the accelerator opening sensor 51. Throttle opening control unit 53, based on the throttle valve control command SG1, controls the opening of the electronic throttle 5 2.

The engine rotation speed sensor 54 detects the rotation speed Ne of the engine 20 and outputs a signal indicating the rotation speed Ne of the engine 20 to the control device 100. Here, the engine rotation speed Ne corresponds to the rotation speed of the crankshaft 23.
Throttle opening sensor 55 detects the opening TA of the electronic throttle 5 2, and outputs a signal indicating the detection result to the controller 100.
The vehicle speed sensor 56 detects the vehicle speed V from the rotational speed No. of the output shaft 120 c of the automatic transmission 10 and outputs a signal indicating the detection result to the control device 100.

The operation position sensor 57 detects the operation position of the shift lever of the automatic transmission 10 and outputs a signal indicating the detection result to the control device 100.
The turbine rotation speed sensor 58 substantially detects the input shaft rotation speed Nin by detecting the rotation speed of the turbine 26 or the rotation speed of the clutch drum of the clutch C0, and outputs a signal indicating the detection result to the control device 100. To do. Here, the input shaft rotation speed Nin corresponds to the rotation speed of the input shaft 25.

  The control device 100 performs fuel cut control by closing the fuel injection valve 80 of the engine 20. In the fuel cut control, in a driven state (when the vehicle is decelerating) such as when the accelerator opening is fully closed as in the present embodiment, the control device 100 performs a predetermined fuel cut return rotational speed. The fuel injection valve 80 of the engine 20 is closed during a period when the engine rotational speed Ne is higher than that.

  In the present embodiment, when the lockup clutch 31 is engaged in the driven state, the engine rotational speed Ne increases due to the rotational force of the drive wheels (corresponding to the input shaft rotational speed Nin). As a result, it is possible to extend the period during which the engine rotational speed Ne is higher, which contributes to an improvement in fuel consumption.

  The control device 100 executes engagement control and slip control of the lockup clutch 31. In the ROM 79 of the control device 100, the lockup clutch 31 is released in the first gear stage (1st) and the second gear stage (2nd) of the automatic transmission 10 regardless of the throttle opening degree TA and the vehicle speed V. Then, it is set in advance. Further, in the ROM 79, at the third shift speed (3rd) to the fifth shift speed (5th) of the automatic transmission 10, for example, as shown in FIG. Correspondence) Based on V, it is set that the lockup clutch 31 is disengaged, slip-controlled, or engaged.

  When the automatic transmission 10 is in the third shift speed (3rd) to the fifth shift speed (5th), the control device 100 performs release of the lockup clutch 31, slip control, and engagement based on the relationship of FIG. Which one is to be performed is determined, and a lockup clutch control signal SG2 indicating any one of the determined release, slip control, and engagement is output to the hydraulic control device 34.

  Based on the lock-up clutch control signal SG2, the hydraulic control device 34 controls the hydraulic pressure supplied to the engagement-side oil chamber 32 and the release-side oil chamber 33 of the torque converter 21, as described above, and the lock-up clutch 31. To generate one of the states of release, slip and engagement.

  In the slip control described above, the rotational loss of the torque converter 21 is made as much as possible by absorbing the rotational fluctuation of the engine 20 for the purpose of improving the fuel efficiency as much as possible without impairing the drivability in the driving state of the vehicle. Therefore, the lockup clutch 31 is maintained in the slip state.

  Further, even when the vehicle is driven, that is, during deceleration coasting, the engine rotation speed Ne is made higher than the fuel cut return rotation speed to expand the control range of the fuel cut control, or a large deceleration G is applied to the vehicle. For this purpose, deceleration slip control is executed as the engagement control during deceleration of the lockup clutch 31. This deceleration slip control is executed on condition that the throttle valve opening TA is substantially zero, the vehicle speed V is equal to or higher than a predetermined value, and the like.

  The control device 100 outputs a braking force control signal SG3 to the brake (braking force) control device 230. The brake control device 230 applies a predetermined deceleration G to the vehicle by operating the foot brake for a predetermined amount for a predetermined time based on the braking force control signal SG3. In this embodiment, instead of the brake control device 230, a braking force control device 230 that operates a regenerative brake of a rear motor generator or engages a brake B3 or B4 that is an engagement element of the automatic transmission 10 is used. can do. Here, the regenerative brake of the rear motor generator is disposed between the lock-up clutch 31 and the drive wheels, and can reduce the drive force transmitted to the drive wheels.

  In the present embodiment, a braking force control device 230 that applies a predetermined braking force by controlling the operating state of the brake or the regenerative brake or the engagement state of the engagement element of the automatic transmission, and the electronic throttle devices 52 and 53 are used. Thus, the lockup clutch 31 is brought into an engageable state without changing the driving force characteristics (such as tire torque). In this case, in the present embodiment, the control using the braking force control device 230 and the electronic throttle devices 52 and 53 is performed when the vehicle is in the “driven state” or “at the time of transition from the driving state to the driven state”. To be done. Hereinafter, the time when the control of this embodiment is performed will be described.

  As described above, it is difficult to engage the lockup clutch 31 when the vehicle is in a driven state (a state where the engine 20 generates negative torque). As shown in FIG. 6, when the accelerator opening is fully closed at the time T1, the engine torque starts to decrease slightly later than the time T1, and the decrease proceeds with time, and the time T2 And after that time T2, a negative torque is generated.

  Here, the “driven state” is after the time point T2, and the “transitional state from the driven state to the driven state” is between T1 and T2. The present embodiment realizes reliable engagement of the lockup clutch 31 in the “driven state”. However, in consideration of a response delay in control of a brake or the like, “from the driven state to the driven state”. The control of the braking force control device 230 and the electronic throttle device 52 is started from the “transition time”.

  In addition, after shifting to the “driven state”, a downshift command is issued and the engine may generate a larger negative torque (when it becomes difficult to engage the lockup clutch 31 newly). In the “driven state”, control of the braking force control device 230 and the electronic throttle device 52 is started.

  Next, the operation of this embodiment will be described with reference to FIG. FIG. 1 shows a control flow of the first embodiment. 1 is stored in advance in the ROM 79 of the control device 100.

[Step S1] and [Step S2]
In step S1, it is determined whether or not the accelerator is fully closed. Control device 100 determines whether or not the accelerator is fully closed based on the detection result of accelerator opening sensor 51. If the result of determination in step S1 is that the accelerator is fully closed (step S1-Y), the flag F is checked in step S2.

  In step S2, since the flag F = 0 at the beginning of this control flow, the process proceeds to step S3. On the other hand, if the result of determination in step S1 is that the accelerator is not fully closed (step S1-N), the process proceeds to step S11, where the control of the braking force control device 230 and the electronic throttle 52 is terminated / stopped.

[Step S3]
In step S3, it is determined whether or not the lock-up clutch 31 is determined to be engaged. Here, the control device 100 determines whether or not the lockup clutch 31 should be engaged. This determination is made with respect to gears (third gear to fifth gear) other than the gears (first gear and second gear) preset in the ROM 79 as releasing the lockup clutch 31. FIG. It is done with reference to.

  As shown in FIG. 5, based on the output shaft rotational speed No and the throttle valve opening TA of the automatic transmission 10, the state of the lockup clutch 31 is determined to be one of disengagement, slip control, and engagement. On the other hand, regarding the shift speeds (first shift speed and second shift speed) that are set in advance to release the lockup clutch 31, the determination result in step S3 is negative.

  As a result of the determination in step S3, if it is determined that the engagement determination of the lockup clutch 31 is present (should be engaged) (step S3-Y), step S4 is performed. On the other hand, as a result of the determination in step S3, when it is determined that the engagement determination of the lockup clutch 31 is not present (not to be engaged) (step S3-N), this control flow is reset.

[Step S4]
In step S4, a command to engage the lockup clutch 31 is output (step S4). The engagement command for the lockup clutch 31 is output from the control device 100 to the hydraulic control device 34 as a lockup clutch control signal SG2. Step S5 is performed after step S4.

[Step S5]
In step S5, an opening command for the electronic throttle 52 is output. That is, the opening amount of the electronic throttle 52 is increased from the opening amount of the electronic throttle 52 corresponding to the normal accelerator opening. The control device 100 outputs the opening command for the electronic throttle 52 in step S5 to the throttle opening control device 53 as the throttle valve control command SG1. This step S5 is executed simultaneously with step S4. Following step S5, step S6 is performed.

[Step S6]
In step S6, simultaneously with step S5, the braking force control device 230 performs control to increase the braking force so as to cancel the increase in the tire driving force due to the electronic throttle opening command (step S5). The control device 100 outputs a braking force control signal SG3 indicating the braking force to be increased in step S6 to the braking force control device 230. Subsequent to step S6, step S7 is executed.

[Step S7] and [Step S13]
In step S7, it is determined whether or not the engagement of the lockup clutch 31 is completed. When the engine rotational speed Ne and the input shaft rotational speed (the rotational speed of the rotating element (AT member) constituting the automatic transmission 10) Nin are the same (see t5 in FIG. 2), the control device 100 It is determined that the engagement of the lockup clutch 31 has been completed.

  As a result of the determination in step S7, when the engagement of the lockup clutch 31 is not completed (step S7-N), the flag F is set to 1 (step S13), and then this control flow is reset, It waits for the engagement of the lockup clutch 31 to be completed in steps S1 → S2 → S7.

  If the fully closed state of the accelerator is released by the time the engagement of the lockup clutch 31 is completed (if the accelerator pedal 50 is depressed), the control of the braking force control device 230 and the electronic throttle 52 is stopped ( Step S11). In this case, the control mode of the braking force control device 230 and the electronic throttle 52 is such that the driver does not feel uncomfortable by gradually decreasing the control amount. On the other hand, when it is determined that the engagement of the lockup clutch 31 is completed as a result of the determination in step S7 (step S7-Y), the process proceeds to step S8.

[Step S8]
In step S8, a closing command for the electronic throttle 52 is output. Here, a command is output so that the electronic throttle 52 is gradually (gradually) closed. The control device 100 outputs the electronic throttle 52 closing command in step S8 to the throttle opening control device 53 as the throttle valve control command SG1. Following step S8, step S9 is executed.

[Step S9] and [Step S10]
In step S9, a command for gradually decreasing the braking force by the braking force control device 230 is output. The control device 100 outputs the braking force gradual decrease command in step S9 to the braking force control device 230 as a braking force control signal SG3. Step S9 is executed simultaneously with step S8. Thereafter, after the flag F = 0 is set, this control flow is reset.

[Step S11] and [Step S12]
As described above, when the accelerator is not fully closed (step S1-N), the control of the braking force control device 230 and the electronic throttle 52 is ended in step S11. When the control of the braking force control device 230 and the electronic throttle 52 is not executed, it is left as it is. Following step S11, the flag F is set to F = 0 (step S12), and this control flow is reset.

  Next, with reference to FIG. 2, an operation related to the engagement of the lockup clutch 31 of the present embodiment will be described.

  FIG. 2 is a time chart for explaining the present embodiment. FIG. 2 shows the engine rotational speed Ne, the input rotational speed of the automatic transmission 10 (the rotational speed input to the automatic transmission 10 on the downstream side of the torque converter 21) Nin, the accelerator opening, the MG regenerative brake or the brake. The control amount, the opening degree of the electronic throttle 52, the shift command, the tire torque, and the train torque are shown.

  First, a conventional general operation when the control according to the present embodiment is not performed will be described.

  As shown in FIG. 2, the accelerator is turned off at time t1, and the accelerator opening 101 becomes zero. In general, the opening 102 of the electronic throttle 52 generally begins to decrease substantially simultaneously with the accelerator off at the time t1, and is fully closed slightly later than the accelerator opening 101, as indicated by the broken line in the figure. The tire torque 103 at this time decreases with time and shifts from a positive value to a negative value. Here, the vehicle is in a driving state when the tire torque 103 is a positive value, and is in a driven state when the tire torque 103 is a negative value.

  In the characteristics of the tire torque 103 as shown in FIG. 2, when the engagement determination of the lockup clutch 31 is made at the time t2 (step S3-Y), the driven state (tire torque 103 is negative: power Since the lock-up clutch 31 is in an off state, it is difficult to engage the lock-up clutch 31.

  If the lock-up clutch 31 is not engaged, as indicated by a two-dot chain line denoted by reference numeral 107, the engine rotational speed 107 is decreased, and the fuel cut is restored (fuel cut) below the predetermined fuel cut return rotational speed. ), Fuel consumption deteriorates. When it is difficult to engage the lock-up clutch 31 in the driven state of the vehicle, the lock-up clutch 31 that increases the engine rotation speed Ne higher than the fuel cut return rotation speed and expands the control range of the fuel cut control. It becomes difficult to execute the deceleration slip control. Therefore, in the present embodiment, the following operation is performed in order to reliably engage the lockup clutch 31 in the driven state of the vehicle.

  Below, operation | movement when control of this embodiment is performed is demonstrated.

  In the present embodiment, in the above case, the engagement determination of the lockup clutch 31 is made at time t2 (step 3-Y), and when the engagement command of the lockup clutch 31 is output (step S4), the t2 In the vicinity of the time point, the closing operation of the electronic throttle 52 is stopped halfway (see the solid line compared with the broken line of the electronic throttle opening 102 in step S5).

  In the above, if the closing operation of the electronic throttle 52 is stopped halfway around the time t2, the tire torque characteristic 103 becomes the driving state side as indicated by the alternate long and short dash line (or the driven state is entered). Even if this happens, the deceleration torque corresponding to the fully closed state of the accelerator cannot be obtained sufficiently).

  Therefore, as shown by reference numeral 104, correction control is performed by the braking force control device 230 to compensate for the shortage of the deceleration torque (step S6). By the correction control, the characteristic (driving force characteristic) of the tire torque 103 is set to the same state (the tire torque 103 indicated by the solid line) as when the closing operation of the electronic throttle 52 is not stopped halfway (normally normal operation). And does not affect drivability.

  In this case, since the closing operation of the electronic throttle 52 is stopped halfway, the power train is in a power-on state (the train torque 105 remains a positive value). In this state, the lockup clutch 31 can be engaged without any problem.

  The broken line 105 indicates the train torque 105 when the closing operation of the electronic throttle opening 102 is not stopped halfway, and at the time t2 when the engagement determination (step S3-Y) of the lockup clutch 31 is made. Since the train torque 105 has a negative value, it is difficult to engage the lockup clutch 31. On the other hand, in the present embodiment, the lockup clutch 31 can be engaged without any problem by controlling so that the train torque 105 does not become a negative value.

  The lockup clutch 31 is engaged, for example, based on an engagement command (step S4) that is output simultaneously with the engagement determination at the time t2 (step S3-Y), as indicated by the engine speed 107, as shown in FIG. This is performed from time t3 to time t5. With the engagement of the lock-up clutch 31, the engine rotation speed at the time point from t3 to t5 is as much as there is no transmission loss (slip) of the rotational force of the drive wheel (corresponding to the input rotation speed 106, Nin) by the torque converter 21. 107 gradually rises. Here, the input rotational speed 106 corresponds to the rotational speed of the input shaft 25 (FIG. 3), and the engine rotational speed 107 corresponds to the rotational speed of the crankshaft 23.

  When the engagement of the lockup clutch 31 is completed at the time t5, the input / output members of the torque converter 21 are mechanically coupled directly, so that the input rotational speed 106 and the engine rotational speed 107 coincide.

  At the time point t4, based on the relationship between the input rotational speed 106 and the engine rotational speed 107, immediately before completion of engagement of the lockup clutch 31 is detected (step S7-Y), the electronic throttle is opened from the time point t5 onward. The degree 102 and the braking force 104 are gradually reduced (step S8 and step S9).

  As described above, according to the present embodiment, the lock-up clutch 31 can be engaged even when the vehicle is in a driven state or a transition from the driven state to the driven state, and the fuel during deceleration can be achieved. Cut is effectively realized and fuel efficiency is improved.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. In the second embodiment, parts that are the same as in the above embodiment are given the same reference numerals, and descriptions thereof are omitted.

  In the first embodiment, the case where the lockup clutch 31 is in the engaged state has been described. In the second embodiment, the case where the lockup clutch 31 is in the slip state (half-engaged) will be described.

  In the control flow of the second embodiment shown in FIG. 8, “engagement” in steps S3, S4, and S7 of the control flow of the first embodiment shown in FIG. It has been changed to. The rest is common to the control flow of the first embodiment.

  FIG. 9 shows a time chart of the second embodiment. In FIG. 3, only the relationship between the engine speed 107 and the input speed 106 is different from FIG. When the lock-up clutch 31 is half-engaged as in the second embodiment, after the half-engagement is completed (step S7, after t5), for example, about 50 [ rpm], the engine rotation speed 107 is maintained at a lower level. Since the accelerator is turned off at t 1 and the vehicle is in a driven state, the input rotational speed 106 is higher than the engine rotational speed 107.

  According to the second embodiment, the lock-up clutch 31 can be half-engaged (slip state) even when the vehicle is in a driven state or a transition from the driving state to the driven state, and the fuel during deceleration Cut is effectively realized and fuel efficiency is improved.

(Third embodiment)
Next, a third embodiment will be described with reference to FIG. In the third embodiment, parts that are the same as those in the above embodiments are given the same reference numerals, and descriptions thereof are omitted.

In the third embodiment, the lock-up clutch is reliably engaged when a shift is performed when the vehicle is in a driven state or a transition from the driven state to the driven state. With reference to FIG. 10 , the control flow of 3rd Embodiment is demonstrated.

  As in the first embodiment, first, it is determined whether or not the accelerator is fully closed (step S1). If it is fully closed (step S1-Y), the flag F is checked (step S2). Since the flag F is initially zero, step S3 is performed.

[Step S3]
In step S <b> 3, the control device 100 determines whether or not to downshift based on the vehicle speed V and the throttle opening TA according to a shift map (not shown) stored in the ROM 79. As a result of the determination in step S3, control device 100 performs step S4 when determining that a downshift is to be performed (step S3-Y), and when determining that no downshift is to be performed (step S3-N). Passes step S4 and performs step S5.

[Step S4]
In step S <b> 4, the control device 100 outputs a downshift command to the hydraulic control device 34. The hydraulic control device 34 controls the hydraulic pressure for engaging / disengaging the engagement elements and the like of the automatic transmission 10 as shown in FIG. 4 in order to shift to the gear stage instructed by the downshift command. Following step S4, step S5 is performed.

  Step S5 and step S6 are common to step S3 and step S4 in FIG. As shown in parentheses in step S5, step S6, and step S12, this control flow can be performed in common in the case of engagement / half-engagement.

  In the third embodiment, as shown in steps S3 to S6, the downshift operation (steps S3 and S4) is performed before the engagement operation (steps S5 and S6) of the lockup clutch 31. . In general, since the time from the engagement command of the lockup clutch 31 to the start of engagement is long, in the third embodiment, the engagement of the lockup clutch 31 is started after downshifting (step S3). To step S6).

  This can be realized by controlling the engagement operation of the lockup clutch 31 (for example, starting the engagement after a predetermined time has elapsed after receiving the engagement command). Further, instead of such engagement control of the lockup clutch 31, it can also be realized by outputting an engagement command (step S6) after a predetermined time elapses after the shift command (step S4).

[Step S7]
In step S7, it is determined whether or not non-shifting or shifting has been completed. As a result of the determination, if it is not completed (step S7-N), the flag F is set to 1 (step S15) and waits until it is completed (step S2 → step S7). When completed, step S8 is performed.

  Steps S8 to S11 are the same as steps S3 to S9 in FIG. Following step S11, step S12 is performed.

[Step S12]
If the half-engagement command for the lockup clutch 31 is output in step S6, half-engagement control (slip control) for the lockup clutch 31 is performed as step S12. That is, when the lock-up clutch 31 is half-engaged, feedback is performed so that the input rotational speed 106 and the engine rotational speed 107 are maintained at a predetermined rotational speed (50 [rpm] in the above example) as described above. Control is performed.

  According to the third embodiment, regarding the shift speed selection control as described above, the optimum high speed stage (fourth speed in the above example) in terms of fuel consumption is selected as the shift stage when the accelerator is off. The shift map can be set so that the vehicle is easily driven, and the downshift is performed in accordance with the accelerator off in a state where the vehicle is driven by the accelerator off, and the gear position after the downshift (in the above example, 3 Speed), the lockup clutch can be reliably engaged.

  In the third embodiment, a case has been described in which the lockup clutch is (half) engaged when the downshift is performed in accordance with the power-off state. Even in the case where the lockup clutch is (half) engaged when shifting is performed, the (half) engagement of the lockup clutch can be reliably performed with the same control flow.

  As described above, in the present embodiment, in the driven state, the tire torque (whole vehicle) is maintained in the driven state, and the power train (train torque) is (virtually) set to the driving state (power-on state). To do. As a result, it is possible to reliably engage the lockup clutch while suppressing deterioration of drivability.

  In order to bring the power train into the driving state when the accelerator is off, the electronic throttle is controlled to the open state. In order to set the tire side to the driven state, a braking force is applied by actuating a foot brake, a regenerative brake of the rear motor generator, or a brake which is an engagement element of the automatic transmission.

  As in this embodiment, when the lock-up clutch is engaged or half-engaged at a predetermined speed (the third speed in the above example) or more, at the time of an upshift (power-off up) accompanying the accelerator off, or after that Since the vehicle is in a driven state (power-off state), conventionally, it has been difficult to engage or half-engage the lock-up clutch. However, in this embodiment, there is no problem even in such a case. The lock-up clutch can be engaged or semi-engaged.

  In general, when shifting is performed, a load exceeding the inertia torque is applied to the engine, so that a release-side force is applied to the lockup clutch in the engaged state or the semi-engaged state. When the vehicle is in a driving state, a release-side force acts on the lock-up clutch during an upshift. When the vehicle is in a driven state, a release-side force acts on the lockup clutch during downshifting.

  If a downshift is performed when the vehicle is in a driven state, the engine rotational speed Ne is increased, and a force toward the disengagement side acts greatly on the lockup clutch.

  When a downshift in the driven state of the vehicle accompanying the accelerator off is performed and a force toward the release side acts on the lockup clutch, conventionally, the engagement of the lockup clutch is against the force toward the release side. In order to maintain or return to the combined state or the semi-engaged state, the control is performed to generate a positive engine torque to drive the vehicle, thereby maintaining or returning the engaged state or the semi-engaged state. It was thought. On the other hand, according to the present embodiment, when the downshift in the driven state of the vehicle accompanying the accelerator off is performed and a force toward the release side acts on the lockup clutch, the vehicle is in the driven state. In this state, the engagement state or the semi-engagement state of the lockup clutch can be maintained or returned without any problem.

  In each of the above embodiments, the transmission has been described as the stepped automatic transmission 10, but may be a continuously variable transmission.

It is a flowchart which shows the control method of 1st Embodiment of the driving force control apparatus for vehicles of this invention. It is a time chart which shows operation | movement of 1st Embodiment of the driving force control apparatus for vehicles of this invention. 1 is a configuration diagram illustrating a lockup clutch, a torque converter, and an automatic transmission to which a first embodiment of a vehicle driving force control device of the present invention is applied. It is a figure which shows the action | operation table | surface of the automatic transmission to which 1st Embodiment of the vehicle driving force control apparatus of this invention is applied. It is a block diagram which shows the structure of 1st Embodiment of the driving force control apparatus for vehicles of this invention. It is explanatory drawing for demonstrating the time of operation | movement of 1st Embodiment of the driving force control apparatus for vehicles of this invention. It is a graph which shows the engagement, slip, and release | release area | region of the lockup clutch of 1st Embodiment of the driving force control device for vehicles of this invention. It is a flowchart which shows the control method of 2nd Embodiment of the driving force control apparatus for vehicles of this invention. It is a time chart which shows operation | movement of 2nd Embodiment of the driving force control apparatus for vehicles of this invention. It is a flowchart which shows the control method of 3rd Embodiment of the driving force control apparatus for vehicles of this invention. It is explanatory drawing for demonstrating the state of the lockup clutch at the time of the drive of the conventional general vehicle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Automatic transmission 20 Engine 21 Torque converter 23 Crankshaft 24 Pump 25 Input shaft 26 Turbine 31 Lockup clutch 32 Engagement side oil chamber 33 Release side oil chamber 34 Hydraulic control device 35 Front cover 36 Lockup piston 50 Accelerator pedal 51 Accelerator Opening sensor 52 Electronic throttle 53 Throttle opening control device 54 Engine rotation speed sensor 55 Throttle opening sensor 56 Vehicle speed sensor 58 Turbine rotation speed sensor 79 ROM
80 Fuel injection valve 100 Control device 120c Output shaft 230 Braking force control device C0 to C2 Clutch B0 to B4 Brake Ne Engine rotation speed Ni Input shaft rotation speed No Output shaft rotation speed SG1 Throttle valve control command SG2 Lockup clutch control signal SG3 Braking force control signal T Torus TA Throttle opening V Vehicle speed

Claims (3)

An engine output control unit for controlling the output of the engine;
A drive force reduction means provided between a lockup clutch provided between the engine and the drive wheel and a drive force transmitted between the drive wheel and capable of reducing the drive force transmitted to the drive wheel;
When the vehicle is in a driven state or when the vehicle is in a transition from a driving state to a driven state and the lock-up clutch is engaged or semi-engaged, the lock-up clutch Compared to the case where the engine is not engaged or half-engaged, the engine output control unit increases the opening of the electronic throttle and increases the engine output by injecting fuel with the fuel injection valve. And the driving force reduction means cancels the increase in the driving force of the driving wheel due to the control simultaneously with the control in the engine output control unit that performs the output of the engine to be increased. the vehicle driving force control apparatus characterized by a work moving the Ru reduce the driving force transmitted to. The vehicle driving force control device according to claim 1,
The vehicle driving force control device, wherein the driving force reducing means is at least one of an engagement element of a transmission, a brake, and a motor generator. In the vehicle driving force control device according to claim 1 or 2,
Furthermore,
A first detection unit for detecting a rotation state of a rotating body between the lock-up clutch and the drive wheel;
A second detector for detecting the rotational state of the engine;
Based on the detection result of the rotation state of the rotating body and the detection result of the rotation state of the engine, the control by the engine output control unit and the operation of the driving force reduction means are terminated. Force control device.

Images