JP2003049676A - Output torque control device for vehicle power source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control system that can determine a slip of a driving wheel via a simple structure and can avoid resultant racing of a power source and a drop in driving torque after the slip. SOLUTION: The output torque control system, which is for the power source in a vehicle having a drivetrain for transmitting torque output from the power source to the driving wheels via a mechanism with a transmission function, comprises a power source controlling means (Steps S7, S8, S10 and S13) for increasing and decreasing the output torque of the power source according to a vehicle speed of the vehicle or a rotational speed corresponding to the vehicle speed, and a rotational speed of the driving wheels or a member rotatable integrally with the driving wheels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle configured to transmit torque from a power source such as an internal combustion engine to drive wheels through a drive system including a mechanism having a speed change function such as a continuously variable transmission. The present invention relates to a device that controls the output torque of a power source, and particularly to a device that controls the output torque based on the determination of the slip of the drive wheels.

[0002]

2. Description of the Related Art In various vehicles such as a vehicle using an internal combustion engine as a power source or a vehicle using an internal combustion engine and an electric motor as a power source, a transmission is used in order to generate a driving force according to a request. It is configured to transmit torque to the drive wheels via the drive system including the drive wheels. As its drive system,
The one with the strength and torque capacity required for the vehicle is adopted,
Also, during actual operation, the torque capacity is controlled so as not to become excessively large. However, since the torque acting on the drive system changes greatly while the vehicle is running, it is necessary to control in consideration of fluctuations in the torque. Depending on the content of the control, inconvenience such as deterioration of fuel consumption may occur. is there.

As an example, a vehicle having a continuously variable transmission will be described. As a continuously variable transmission for a vehicle, a torque transmitting member such as a belt or a power roller is directly or oily to a rotating body such as a pulley or a disk. There is known a continuously variable transmission that is configured to continuously change the gear ratio by making contact with each other indirectly and changing the portion that transmits torque between these members in the radial direction. ing. In this type of continuously variable transmission, the surface of the rotating member has a smooth curved surface so that the torque transmitting position between the rotating member and the torque transmitting member can be continuously changed.

In order to transmit necessary and sufficient torque between the curved surface and the torque transmitting member, in a belt type continuously variable transmission, the belt is sandwiched by pulleys composed of a fixed sheave and a movable sheave. The clamping force is set so that a frictional force corresponding to the torque to be applied and transmitted is generated between the pulley and the belt. Further, in a toroidal type (traction type) continuously variable transmission using a power roller, the shear force of the oil film interposed between the input roller and the output roller and the power roller is different from the shear force corresponding to the torque to be transmitted. The sandwiching force of the power roller by each disk is set so that

In the continuously variable transmission, the holding pressure for holding the torque transmission member may be at least a pressure determined based on the torque to be transmitted. However, if the clamping pressure is higher than necessary, the power transmission efficiency of the continuously variable transmission will be reduced, and the durability of the continuously variable transmission will be reduced. Furthermore, the clamping pressure must be set hydraulically. If configured, the power loss in the hydraulic pump increases, and eventually the fuel economy of the vehicle equipped with the continuously variable transmission deteriorates.

Therefore, the most preferable pinching pressure in the continuously variable transmission is the pressure that sets the state immediately before slippage occurs between the rotating member and the torque transmitting member, and such pressure control is usually feedback control. Alternatively, it is performed by feedforward control or control that combines these controls. For such control,
After the driving wheels temporarily idle on a so-called low μ road or on a step on the road surface, a situation such as gripping the road surface or sudden braking, or a situation where the antilock brake system (ABS) acts, The torque applied to the drive system is large and changes abruptly, which causes disturbance. When such a disturbance state occurs, a torque exceeding the assumed torque acts on the continuously variable transmission, and slippage may occur on the belt or the like.

If the continuously variable transmission is excessively slipped and its torque transmitting surface is damaged, the continuously variable transmission will not operate normally. Therefore, in general, excessive slippage is detected or estimated. If so, control is performed to increase the torque capacity of the continuously variable transmission, such as increasing the clamping pressure described above. However, control for increasing the torque capacity of the continuously variable transmission has unavoidable restrictions such as control delay and insufficient control amount, and it may not always be possible to reliably prevent excessive slippage of the continuously variable transmission. .

On the other hand, an apparatus for executing a control for reducing the engine torque when the drive wheels slip is described in, for example, Japanese Patent Application Laid-Open No. 5-149157. In the invention described in this publication, when the engine torque is controlled by the throttle opening, if the throttle opening is controlled so as to achieve the target torque based on the slip of the driving wheels, the control delay may cause an overshoot. Therefore, the torque adjustment time for increasing or decreasing the engine torque by a predetermined amount is changed based on the slip state of the drive wheels.

[0009]

In a vehicle such as a vehicle equipped with a continuously variable transmission in which the torque applied to the drive system is restricted, when the drive wheel slips, it acts on the output side of the continuously variable transmission. Since the negative torque that has been reduced decreases rapidly, the rotational speed of the power source rapidly increases. Therefore, in this case, the torque that acts on the continuously variable transmission decreases.
However, if the grip force is restored after the drive wheels slip, the output shaft and the drive wheels integrated with the output shaft will not rotate when the rotation speed of the drive system from the power source to the drive wheels increases. Since the torque rapidly decreases, a large torque including the inertia torque suddenly acts on the continuously variable transmission.

The invention described in the above publication is an invention configured to perform control for reducing the engine torque when the drive wheels slip, and the drive wheels exert a grip force after the slip. It is not configured to perform control for coping with a large torque applied to the drive system when recovered. Therefore, in the invention described in the above publication, it may not be possible to reliably avoid slippage in the continuously variable transmission due to a large torque applied to the drive system after slipping of the drive wheels. On the other hand, on the contrary, although the engine torque can be sufficiently reduced, the drive torque at the time when the drive wheel recovers the grip force becomes insufficient, which may cause a feeling of deceleration or a feeling of pulling in, which may impair drivability. .

On the other hand, in order to avoid excessive slippage in the continuously variable transmission, it is necessary to constantly monitor the operating state of the continuously variable transmission, and at least detect the slip condition. If a sensor is attached to the continuously variable transmission in order to detect such an operating state of the continuously variable transmission, accurate control becomes possible, but disadvantages such as an increase in vehicle weight and cost occur. .

The present invention has been made in view of the above technical problems, and is intended for situations in which the rotational speed of a power source increases or torque acting on a drive system increases, such as when the drive wheels slip. An object of the present invention is to provide a control device capable of accurately controlling the output torque of a power source without increasing control equipment excessively.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention relates to a situation in which the torque applied to a drive system increases and a vehicle speed or a rotational speed corresponding thereto and a drive wheel or an integral body thereof. It is characterized in that the determination is made based on the rotational speed of the member and the output torque of the power source is controlled. More specifically, the invention of claim 1 is an output torque control device for a power source for a vehicle having a drive system for transmitting torque output from a power source to drive wheels through a mechanism having a gear shifting function, in the vehicle. A power source control means for increasing / decreasing the output torque of the power source based on the vehicle speed or a rotation speed corresponding thereto and a rotation speed of the drive wheel or a member rotating integrally with the drive wheel. It is a characteristic control device.

As described in claim 2, the power source control means in claim 1 is configured to change the manner of decreasing the output torque of the power source according to the operating state of the power source. be able to.

Therefore, according to the first or second aspect of the present invention, the vehicle speed normally detected as the vehicle or the rotational speed corresponding to the vehicle speed, and the rotational speed of the drive wheels or the rotational speed corresponding to the rotational speed of the wheels are used. Since the slip state is determined, the slip of the wheel can be determined without using special sensors, and as a result, the overall configuration can be simplified. Also, since the output torque of the power source is increased or decreased based on the result of the determination,
It is possible to effectively prevent the power source from being blown up, and to prevent a drop in torque when the wheels are gripped again, a shock, or an excessive torque acting on the drive system.

Further, the invention of claim 3 has a drive system for transmitting the torque output from the power source to the drive wheels via a mechanism having a gear shifting function, and the power is transmitted when the slip of the drive wheels is determined. In a vehicle power source output torque control device for reducing the output torque of a power source, a plurality of output torque reducing means having different output torque reducing characteristics and the output torque reducing means according to a slip state of the drive wheels are provided. And a selecting means for reducing the output torque of the power source by the selected output torque reducing means.

The selecting means may be configured to change the output torque reducing means while the output torque of the power source is being reduced, as described in claim 4.

Alternatively, the selecting means has a large output torque decrease amount and a relatively slow control response when the slip amount of the drive wheels is large. It is possible to select an output torque reducing means that has relatively fast control response when the drive wheel slip amount is small.

Therefore, while the torque applied to the drive system changes depending on the slip state of the drive wheels, the output torque reducing means changes according to the slip state of the drive wheels. Since the selection is made, the blowing up of the power source due to the slip of the drive wheels is effectively suppressed. In addition, since it is possible to match the timing of eliminating the slip of the drive wheels with the return of the output torque of the power source, the output torque is insufficient at the time when the slip of the drive wheels is eliminated, or conversely, the drive system. A situation in which a large torque acts on the vehicle is avoided in advance. Further, since the amount of decrease in the output torque can be increased, also in this respect, the rising of the power source can be effectively suppressed.

In particular, in the invention of claim 4 or claim 5, in the process in which the drive wheel is gripped again and the amount of slip is gradually reduced, the output torque reducing means is selected according to such behavior of the drive wheel. Therefore, it is possible to reliably avoid the shortage of the output torque at the time when the slip of the drive wheels is eliminated.

The invention of claim 6 has a drive system for transmitting the torque output from the power source to the drive wheels through a mechanism having a gear shifting function, and the power is transmitted when the slip of the drive wheels is determined. In an output torque control device for a vehicle power source that reduces the output torque of the power source, an output torque control unit that changes a reduction amount of the output torque of the power source according to a slip state of the drive wheel, and When slip of the drive wheels is determined again while controlling the reduction amount of the output torque of the power source according to the slip state, the reduction control of the output torque of the power source is performed at that time. An output torque control updating unit that executes a reduction control of the output torque of the power source based on the slippage of the drive wheel that is stopped and newly determined.

Therefore, in the invention of claim 6, when the slip state of the drive wheels is newly determined while the output torque of the power source is being reduced, the output torque of the power source according to the new situation is changed. The drop control is executed. for that reason,
If the content of the control that reduces the output torque of the power source becomes suitable for the operating state of the drive system, and the power source blows up or the drive system includes a continuously variable transmission, The occurrence of excessive slippage is avoided in advance.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described based on specific examples. First, a drive system of a vehicle and a control system thereof which are objects of the present invention will be described. FIG. 4 schematically shows a drive system including a belt type continuously variable transmission 1 as a transmission. The transmission 1 is connected to a power source 3 via a forward / reverse switching mechanism 2.

The power source 3 is composed of an internal combustion engine, or an internal combustion engine and an electric motor, or an electric motor,
The point is a drive member that generates power for traveling. In the following description, the power source 3 will be referred to as the engine 3. Further, the forward / reverse switching mechanism 2 is a mechanism adopted because the rotation direction of the engine 3 is limited to one direction, and outputs the input torque as it is and reversely outputs it. Is configured.

In the example shown in FIG. 4, a double pinion type planetary gear mechanism is adopted as the forward / reverse switching mechanism 2.
That is, a ring gear 5 is arranged concentrically with the sun gear 4, and a pinion gear 6 meshed with the sun gear 4 and another pinion gear 7 meshed with the pinion gear 6 and the ring gear 5 are arranged between the sun gear 4 and the ring gear 5. The pinion gears 6 and 7 are attached to the carrier 8
It is held by both rotation and revolution. And
Two rotating elements (specifically, sun gear 4 and carrier 8)
Is provided with a forward clutch 9 for integrally connecting
Further, a reverse brake 10 that reverses the direction of the output torque by selectively fixing the ring gear 5 is provided.

The continuously variable transmission 1 has the same structure as a conventionally known belt type continuously variable transmission, and each of a driving pulley 11 and a driven pulley 12 arranged in parallel to each other has a fixed sheave, Hydraulic actuators 13, 14
And a movable sheave that can be moved back and forth in the axial direction. Therefore, each pulley 11, 12
Groove width changes by moving the movable sheave in the axial direction, and accordingly, the winding radius of the belt 15 wound around each pulley 11, 12 (effective diameter of the pulleys 11, 12) continuously changes. However, the gear ratio changes continuously. The drive pulley 11 is connected to the carrier 8 which is an output element of the forward / reverse switching mechanism 2.

The hydraulic actuator 14 in the driven pulley 12 receives hydraulic pressure (line pressure or its correction pressure) corresponding to the torque input to the continuously variable transmission 1 via a hydraulic pump and a hydraulic control device (not shown). Is being supplied. Therefore, when each sheave in the driven pulley 12 sandwiches the belt 15, tension is applied to the belt 15 and a clamping pressure (contact pressure) between the pulleys 11 and 12 and the belt 15 is secured. .
On the other hand, the hydraulic actuator 13 in the drive pulley 11 is supplied with pressure oil according to the gear ratio to be set, and the groove width (effective diameter) is set according to the target gear ratio. .

The driven pulley 12 is connected to a differential 17 via a gear pair 16, and torque is output from the differential 17 to drive wheels 18.

Various sensors are provided to detect the operating state (running state) of a vehicle equipped with the continuously variable transmission 1 and the engine 3 described above. That is, the engine 3
Engine speed sensor 19 that detects the number of rotations and outputs a signal, input rotation speed sensor 20 that detects the number of rotations of drive pulley 11 and outputs a signal, and detects the number of rotations of drive wheels 18 and output a signal A wheel rotation speed sensor 21 is provided. Further, although not particularly shown, an accelerator opening sensor that detects a depression amount of the accelerator pedal and outputs a signal, a throttle opening sensor that detects a throttle valve opening and outputs a signal, and a brake pedal are depressed. A brake sensor that outputs a signal in some cases is provided.

In order to control the engagement / release of the forward clutch 9 and the reverse brake 10, the clamping pressure of the belt 15, and the gear ratio, the electronic control unit for a transmission (CVT) is used. -ECU) 22 is provided. The electronic control unit 22 is mainly composed of a microcomputer as an example, performs an operation according to a predetermined program on the basis of input data and data stored in advance, and various states such as forward and reverse or neutral. Also, it is configured to execute control such as setting of required clamping pressure and setting of gear ratio.

Here, an example of data (signals) input to the transmission electronic control unit 22 will be shown.
Of the input rotation speed Nin, the output rotation speed N of the continuously variable transmission 1
Signals of o are input from the corresponding sensors (not shown). Also, from the engine electronic control unit 23 that controls the engine 3, the engine speed Ne signal, the engine (E / G) load signal, the throttle opening signal, and the accelerator pedal (not shown) depression amount. An accelerator opening signal etc. is input. Further, a brake signal, an ABS operation signal, a wheel rotation speed signal and the like are input from an electronic control unit (ABS-ECU) 24 for an anti-lock brake system that avoids locking of wheels.

The control device of the invention intended for a vehicle having the above-mentioned drive system prevents the engine 3 from blowing up when the drive wheels 18 slip, and when the drive wheels 18 re-grip. The engine 3 and the continuously variable transmission 1 are controlled so as to mitigate the increase in the torque applied to the drive system and prevent the continuously variable transmission 1 from slipping. FIG. 1 is a flowchart showing an example of the control, and the example shown here is
This is an example of the case where the drive wheels 18 are gripped again after the drive wheels 18 slip while the vehicle is traveling.

The routine shown in the flow chart of FIG.
It is repeatedly executed every predetermined short time Δt, and first, the vehicle speed V
It is determined whether b is greater than or equal to a predetermined threshold value Vb1 (step S1). The vehicle speed Vb is essentially the ground speed, which is the speed calculated from the rotational speeds of all wheels, the amount of change of the vehicle per unit time calculated by a position detection device such as a navigation device, and the rotational speed of the non-driving wheels. Any of the vehicle speeds obtained from the above may be used. In the example shown in FIG. 1, the rotational speed of the non-driving wheels is adopted. This is to prevent a test on a test device (not shown) such as a chassis dynamo from being mistaken for a running state.

If the determination in step S1 is affirmative because the vehicle is actually traveling, the drive wheels 1
It is determined whether or not slip has occurred in 8 (step S2). Specifically, it is determined whether the rotational speed Va of the drive wheels 18 is faster than the rotational speed Vb of the non-drive wheels, and the difference ΔV between these rotational speeds is equal to or greater than a predetermined threshold value ΔV1.

If the drive wheel 18 slips due to a so-called disturbance condition such as overcoming a low μ road or a step on the road surface, a positive determination is made in step S2. In that case, the flag F is " 1 "(step S
3).

In this case, if the rotational speed of the drive wheels 18 is used to determine the vehicle speed, the upshift may be determined when the determination that the vehicle speed has increased is established. In order to prevent gear shift based on such erroneous determination, a command for fixing the gear ratio is output (step S
4). Further, when the drive wheel 18 slips, a large torque including the inertia torque acts on the drive system with the subsequent re-grip, so that the clamping pressure is increased in order to prevent slipping in the continuously variable transmission 1. A command to output is output (step S5). That is, the driven pulley 1 described above
The hydraulic pressure supplied to the hydraulic actuator 14 on the second side is increased. The increase amount of the hydraulic pressure may be a predetermined constant value, or may be an increase amount that changes based on the driving state of the engine 3 or the traveling state of the vehicle.

Further, a lockup release command is output (step S6). This is because when a torque converter with a lockup clutch (not shown) is provided between the engine 3 and the forward / reverse switching mechanism 2, the lockup clutch is controlled from the completely engaged state to the released side. Is the order of. This is to eliminate the state where the engine 3 and the drive system thereafter are mechanically directly connected.

Then, a mode for reducing the output torque Te of the engine 3 is selected (step S7). That is, a means for reducing the engine torque Te (Te down means) and a control constant are selected. Here, the Te down means is a means for retarding the ignition timing in the engine 3, a means for reducing the opening of an electronic throttle valve for controlling the intake amount of the engine 3, and a means for reducing the fuel supply amount to the engine 3. And so on.

These means have different characteristics for reducing the output torque, and the retarding means has a fast control response, but the amount of decrease in the output torque is relatively small, and the exhaust gas provided in the exhaust system is also different. It becomes a factor that raises the temperature of the purification catalyst. On the other hand, the means for reducing the intake air amount or the fuel supply amount has a slow control response for reducing the output torque, but can increase the reduction amount of the output torque.

When the output torque of the engine 3 is reduced, normally, the ignition timing retard control with good responsiveness is employed. On the other hand, if the engine water temperature is low or the battery terminal voltage is low, there is a high possibility of misfire.Therefore, instead of retarding the ignition timing, the electronic throttle valve should be used to reduce the intake amount. Adopted. Further, when the exhaust gas temperature is high, a control for reducing the intake air amount by an electronic throttle valve is adopted in order to avoid the above-mentioned damage to the exhaust gas purification catalyst.

When a means for reducing the intake air amount is adopted instead of the ignition timing retard control, the control response is slow, so that it is lowered in order to eliminate the inconvenience caused by the delay in the change of the output torque. The output torque reduction mode is set so that the output torque is restored at an early stage. Specifically, the threshold value described later is made different from that in the case of the ignition timing retard control, and the output torque is quickly restored.

As another example of the output torque reduction mode, in a so-called direct injection engine in which fuel is directly injected into the cylinder, when the stratified charge combustion is performed, the fuel injection amount is reduced. Reduce the output torque,
When the air-fuel ratio is close to the stoichiometric air-fuel ratio and homogeneous combustion is performed, retard control of ignition timing is adopted to reduce the output torque.

After the output torque reduction mode is selected in accordance with the state of the engine 3 or the vehicle as described above, control for reducing the output torque of the engine 3 is instructed according to the selected mode (step S8). When the output torque of the engine 3 is reduced, the engine 3 is suppressed or prevented from being blown up, and the drive torque of the drive wheels 18 is reduced, so that the slip of the drive wheels 18 changes. Therefore, in step S9, it is determined whether or not the driving wheels 18 have begun to grip again. Specifically, the change rate ΔΔV of the rotational speed difference ΔV has a negative value, and the rotational speed difference ΔV is equal to a predetermined threshold value ΔV2.
It is determined whether or not the following.

If these conditions are not satisfied,
The drive wheel 18 slips and the number of rotations of the drive wheel 18 is increasing. Therefore, in that case, the control returns without performing any particular control. On the other hand, if the determination in step S9 is affirmative, it means that the drive wheels 18 have begun to grip again. In that case, the rotational speed difference ΔV between the driving wheel 18 and the non-driving wheel gradually decreases. Therefore, the decrease amount ΔTe of the output torque of the engine 3 is calculated based on the rotational speed difference ΔTe.
Decrease according to V (step S10). Specifically, the output torque decrease amount ΔTe is set according to the ratio between the threshold value ΔV2 and the gradually changing rotational speed difference ΔV. Such control is executed by gradually advancing the retarded ignition timing so as to restore it, or gradually opening it so as to restore the reduced throttle opening.

Therefore, since the return control of the reduced output torque is performed on condition that the rotational speed difference ΔV is equal to or less than the threshold value ΔV2, the threshold value ΔV is satisfied.
2 determines the output torque recovery timing.
Therefore, when the output torque reducing means having a slow control response is selected in step S7 described above, the threshold Δ
Set V2 to a large value to accelerate the output torque recovery start timing.

In the process of restoring the output torque of the engine 3 in this way, the rotational speed difference ΔV becomes the third value.
It is determined whether or not the threshold value ΔV3 is less than or equal to the threshold value ΔV3 (step S11). This third threshold value .DELTA.V3 is a small value. Therefore, in step S11, it is judged whether or not the slip amount of the drive wheel 18 has become a slight amount. If the determination in step S11 is negative, it means that the drive wheels 18 are still largely slipping, so the routine returns to continue the conventional control.

On the other hand, if the determination in step S11 is affirmative, it means that the slip of the drive wheels 18 has almost settled (settled), so the flag F is reset to zero (step S12) and the output torque is reduced. Decrease amount ΔT
e is set to zero (step S13). That is, the reduced output torque is completely restored.

Therefore, the timing at which the engine torque once reduced is completely restored is determined by the third threshold value ΔV3. Therefore, when the output torque reducing means having a slow control response is selected in step S7 described above, the threshold value ΔV3 is set to a large value to accelerate the timing for starting the complete recovery of the output torque.

According to the above control, the amount of decrease Δ in the engine torque is caused by the decrease in the slip amount of the drive wheels 18.
When Te is decreased and the drive wheels 18 are gripped again, the output torque reduction control of the engine 3 is completed and the original torque is restored. Therefore, when the slip of the drive wheels 18 ends, the drive torque becomes insufficient,
It is possible to avoid a sense of discomfort due to a feeling of deceleration or a feeling of pulling in.

Such engine torque return control is
It can be executed regardless of the magnitude of the decrease amount ΔTe of the engine torque executed due to the slip of the drive wheels 18. In other words, the engine torque decrease amount ΔTe can be increased. Therefore, according to the above control, the drive wheels 18
Even if a slip occurs, it is possible to effectively prevent the engine 3 from rising, and even if the belt 15 of the continuously variable transmission 1 slips, the engine torque is reduced, so Can be suppressed to prevent damage to the continuously variable transmission 1.

By making the engine torque decrease amount ΔTe zero, the slip of the drive wheels 18 and the accompanying torque decrease control are completed. Therefore, the return command for returning the clamping pressure increased in step S5 to the original state is issued. Is output (step S14), and the lock-up permission control for engaging the lock-up clutch is executed (step S15). Further, a gear ratio fixation release command for releasing the fixation of the gear ratio is output (step S16).

If the determination in step S2 is negative, the flag F is determined (step S17). Such a state occurs both when the drive wheel 18 does not slip and when the slip of the drive wheel 18 is in the process of converging.

In the former case where the drive wheels 18 are not slipping, the flag F is set to "0", and therefore the routine returns without performing any control. On the other hand, in the latter case where the slip of the drive wheels 18 is in the process of converging, the flag F is set to "1", and therefore, the process proceeds to the step S9 described above, and the slip state of the drive wheels 18 is changed. To be judged. The control thereafter is as described above.

Therefore, in the above-described control shown in FIG. 1, the drive wheel 18 is newly slipped during the process of executing the engine torque reduction control based on the slip of the drive wheel 18 which has once occurred, and the determination is made. If so, that is, if the determination in step S2 is affirmative, the control in steps S3 to S16 is executed. As a result,
According to the control shown in (1), the control of the engine torque, the control of the clamping pressure, and the control of the lockup are executed in accordance with the situation such as the slip of the drive wheels 18 occurring in the drive system. It is possible to avoid excessive slippage of the gear 1 and damage of the continuously variable transmission 1 accompanying it.

In addition, when the vehicle is stopped,
If the determination in step S1 is negative, the drive wheels 1
Each control due to the slip of 8 is returned to the normal state.
That is, the flag F is reset to zero (step S1
8) The engine torque decrease amount ΔTe is reset to zero (step S19), a clamping pressure return command is output (step S20), and further lockup is permitted (step S21). Then, a gear ratio fixation release command for releasing the fixation of the gear ratio is output (step S22).

By the way, there are a plurality of means for reducing the engine torque, and the respective characteristics are different. Further, the slip state of the drive wheels 18 and the torque applied to the drive system including the continuously variable transmission 1 corresponding to the slip state also vary depending on the magnitude and duration. Therefore, it is preferable that the means for reducing the engine torque is selected or changed in accordance with the slip state of the drive wheels 18 in addition to being selected according to the operating state of the engine 3 or the vehicle.

From the above viewpoint, the control example shown in FIG. 2 is an example in which the means for reducing the engine torque is switched in the so-called returning process after the drive wheels 18 start gripping again. That is, the control example shown in FIG.
This is a modification of a part of the control example shown in FIG. 1 described above, and the Te down means and the control constant are selected in step S.
7, the engine torque down command I is output (step S8). Since this is the first torque-down command immediately after the slip of the drive wheels 18 is determined, the control response is slow, and the torque-down command is issued by means having a large torque reduction amount. Specifically, it is a control for closing the electronic throttle valve or a control for reducing the fuel supply amount.

Then, it is judged whether or not the slip of the drive wheels 18 tends to converge (step S81). This is because the change rate ΔΔV of the rotational speed difference ΔV is “0”.
It is determined by whether or not If the determination in step S81 is negative, the process returns without performing any particular control. On the contrary, if the determination is affirmative, the engine torque return command I is output (step S82) and the engine torque down command II is output (step S83).

In response to the engine torque return command I in step S82, the control by the engine torque reducing means having a relatively slow control response executed in step S8 is stopped, and the output torque reducing amount by the engine torque reducing means is set to zero. Command control. On the other hand, the engine torque down command II in step S82 is a command control for reducing the output torque of the engine 3 by another engine torque reducing means, for example, the control response is fast and the output torque reduction amount is This is a command for executing retard control of a small ignition timing. Therefore, at the beginning when the slip of the drive wheels 18 is determined, the engine torque reduction control is executed by means of a large torque reduction amount, and after the slip of the drive wheels 18 starts to converge, the engine torque with a quick control response is obtained. Change to drop control.

After step S83, steps S9 to S16 are executed in the same manner as the control shown in FIG. Further, the other controls are executed in the same manner as the example shown in FIG. Therefore, since the engine torque is rapidly returned in response to the re-grip of the drive wheel 18, even if the engine torque is greatly reduced based on the slip of the drive wheel 18, the drive torque is reduced when the slip of the drive wheel 18 ends. It is possible to avoid a shortage of the vehicle and a resulting uncomfortable feeling due to a feeling of deceleration or a feeling of pulling in.

Changes in wheel speeds (rotational speeds of driving wheels and non-driving wheels), wheel speed differential values (rate of change of rotational speed difference described above), output shaft torque, and engine torque when the above control is carried out. It is as shown in FIG. At time t1 when the vehicle is traveling at a predetermined vehicle speed, if the driving wheel 18 is lifted and slips due to acceleration on a low μ road or riding on a step, the wheel speed of the driving wheel 18 starts to increase, and the differential The value is positive,
Moreover, the output shaft torque decreases.

Immediately after that, the determination of the slip of the drive wheels 18 is established at time t2, and as a result, the engine torque is reduced by a predetermined amount ΔTe. As the engine torque is reduced, the increasing tendency of the rotation speed of the drive wheels 18 is
As indicated by the thick solid line in FIG. 3, the torque becomes gentler than when the engine torque reduction control is not executed (thin solid line in FIG. 3). That is, the wheel speed differential value becomes somewhat smaller. Therefore, the engine 3 is prevented from rising.

In this state, the driving wheels 18 re-grip at the time t3, and the wheel speed starts to decrease, so that the differential value becomes a negative value. Also, the output shaft torque increases. When the wheel speed decreases and reaches the above-mentioned second threshold value ΔV2 (at time t4), the engine torque return control is started, and the decrease amount of the engine torque corresponds to the decrease in the rotation speed of the drive wheels 18. Gradually reduced. Then, when the wheel rotation speed difference ΔV decreases to the third threshold value ΔV3, the engine torque is completely restored.

As a result, the timings of the end of the slip of the drive wheels 18 and the return of the engine torque coincide with each other.
A situation in which the output shaft torque (driving torque) drops and a shock is generated is avoided. On the other hand, drive wheel 1
In the conventional control in which the engine torque reduction control is executed regardless of the slip state of No. 8, and the control is continued until the slip of the drive wheels 18 ends, as shown by the broken line in FIG. It lowers and causes shock. On the contrary, in the conventional control in which the engine torque return control is executed at an early point in order to avoid the drop in the output shaft torque, a large torque acts on the continuously variable transmission 1 as the drive wheels 18 grip again. However, there is a high possibility that slippage of the belt 15 and damage accompanying it will occur.

As described above, according to the control device of the present invention, since the end of the slip of the drive wheels 18 and the return of the engine torque can be made to coincide with each other, the output shaft torque and the drive torque drop and the accompanying deceleration. Since it is possible to avoid the feeling, and to increase the amount of decrease in the engine torque, it is possible to suppress the blow-up due to the slip of the drive wheels 18, and to prevent the drive system from being lost when the drive wheels 18 are gripped again. It is possible to suppress the torque applied to the continuously variable transmission 1 and avoid a situation such as excessive slippage of the continuously variable transmission 1. Further, since the slip of the drive wheels 18 can be determined based on the vehicle speed and the wheel speed, it is not necessary to provide a special sensor, and the control device can be simplified and the vehicle weight can be reduced.

The relationship between the above-described concrete example and the present invention will be briefly described below. Step S shown in FIGS. 1 and 2.
7, S8, ~ S83, S10, S13 functional means,
It corresponds to the power source control means in the inventions of claims 1 and 2. Further, the functional means for executing the ignition timing retard control, the throttle opening reduction control, and the like by the engine electronic control unit 23 corresponds to the output torque reduction means in the inventions of claims 3 to 5, and FIG. 1 and FIG.
The functional means of steps S7 to S83 shown in (1) corresponds to the selecting means in the invention of claims 3 to 5.
Further, steps S7 to S13 shown in FIGS.
The functional means of corresponds to the output torque control means in the invention of claim 6, and the drive wheel 1 is executed during execution of these steps.
8 slip is determined and the steps S7 to S1 are performed again.
The functional means for executing 3 corresponds to the output torque control updating means in the invention of claim 6.

It should be noted that the present invention is not limited to the above-mentioned specific examples, and when the slip of the wheel is judged, the difference in the wheel speed may be judged in consideration of the tire diameter difference. The slip may be configured to be determined based on the rate of change of the rotation speed difference. Further, in the above specific example, the example in which the continuously variable transmission 1 is adopted as the transmission is shown, but the present invention can be applied to control of a vehicle having a drive system including a transmission of another type. .

[0068]

As described above, according to the invention of claim 1 or 2, the vehicle speed normally detected as the vehicle or the rotation speed corresponding to the vehicle speed and the rotation speed of the drive wheels or the rotation speed corresponding thereto. Since the slip state of the wheel is determined based on the rotation speed of the wheel, the slip of the wheel can be determined without using special sensors, and as a result, the overall configuration can be simplified. Further, since the output torque of the power source is increased or decreased based on the result of the determination, it is possible to effectively prevent the power source from being blown up, and to reduce the torque or shock when the wheels are re-griped, or to the drive system. It is possible to prevent excessive torque from acting.

According to the invention of claims 3 to 5,
While the torque applied to the drive system changes according to the slip state of the drive wheels, the output torque reduction means is selected according to the slip state of the drive wheels, so that the power source As well as being able to effectively suppress the blow-up, it is possible to eliminate the slippage of the drive wheels and restore the output torque of the power source at the same time. It is possible to avoid a situation where a large torque acts on the drive system.

Particularly, in the invention of claim 4 or claim 5, at the time when the slip amount of the driving wheel becomes gradually smaller and the gripping force of the driving wheel is recovered, the output torque having the characteristic according to such behavior of the driving wheel. Since the lowering means is selected, it is possible to reliably avoid a situation where the output torque is insufficient at the time when the slip of the drive wheels is eliminated or a large torque acts on the drive system.

According to the sixth aspect of the invention, when the slip state of the driving wheels is newly determined while the output torque of the power source is being reduced, the power source of the power source according to the new situation is determined. Since the output torque reduction control is executed, the content of the control to reduce the output torque of the power source becomes suitable for the operating state of the drive system, and the power source blows up or the drive system includes a continuously variable transmission. If so, it is possible to prevent excessive slippage of the continuously variable transmission.

[Brief description of drawings]

FIG. 1 is a flow chart for explaining an example of control by a control device of the present invention.

FIG. 2 is a flowchart for explaining another example of control by the control device of the present invention.

FIG. 3 is a time chart showing changes in wheel speed, output shaft torque, engine torque and the like when the control shown in FIG. 1 is executed.

FIG. 4 is a diagram schematically showing a drive system and a control system of a vehicle equipped with a continuously variable transmission according to the present invention.

[Explanation of symbols]

1 ... Continuously variable transmission, 3 ... Engine (power source), 11 ...
Drive pulley, 12 ... driven pulley, 15 ... belt, 22 ... electronic control unit for transmission (CVT-EC)
U), 23 ... Electronic control unit for engine (E / G-EC
U).

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // F16H 59:44 F16H 59:44 59:46 59:46 63:06 63:06 F term (reference) 3D041 AA07 AA48 AC20 AD02 AD04 AD10 AD22 AD23 AD37 AD41 AE00 AE05 AE07 AE09 AE31 AE37 3G093 AA06 BA01 BA15 CB05 DA01 DA06 DB03 DB04 DB05 DB11 DB15 EA02 PA05 PA08 PA32 VA05 PA02 MA01 VA09 PA02 MA01 FB02 MA01 NA01 VB01W VB02W VB03W VB16Z VB17Z VC01Z VC03Z VD02Z

Claims (6)

[Claims] 1. An output torque control device for a vehicle power source having a drive system for transmitting torque output from a power source to drive wheels through a mechanism having a gear shift function, wherein a rotation speed corresponding to a vehicle speed or a vehicle speed of the vehicle is provided. A power source control means for increasing or decreasing an output torque of the power source based on a speed and a rotational speed of the drive wheel or a member rotating integrally with the drive wheel. Output torque control device. 2. The power source for vehicle according to claim 1, wherein the power source control means includes means for changing a manner of decreasing the output torque of the power source according to an operating state of the power source. Output torque control device. 3. A drive system for transmitting torque output from a power source to drive wheels via a mechanism having a gear shifting function, and reducing output torque of the power source when slip of the drive wheels is determined. In an output torque control device for a vehicle power source, a plurality of output torque reduction means having different output torque reduction characteristics and the output torque reduction means are selected according to a slip state of the driving wheels, and the selected output is selected. An output torque control device for a vehicle power source, comprising: selecting means for reducing the output torque of the power source by a torque reducing means. 4. The selecting means is configured to change the output torque reducing means while the output torque of the power source is being reduced.
An output torque control device for a vehicle power source according to item 1. 5. The selecting means selects an output torque reducing means that has a large decrease amount of the output torque and a relatively slow control response when the slip amount of the driving wheels is large, and The output torque control device for a vehicle power source according to claim 3 or 4, wherein the output torque control device is configured to select an output torque reducing means having a relatively fast control response when the slip amount is small. 6. A drive system for transmitting torque output from a power source to a drive wheel through a mechanism having a speed change function, and reducing output torque of the power source when slip of the drive wheel is determined. In an output torque control device for a vehicle power source, output torque control means for changing a reduction amount of output torque of the power source according to a slip state of the drive wheels, and the power according to a slip state of the drive wheels. When the slip of the drive wheels is determined again while controlling the reduction amount of the output torque of the power source, the control of reducing the output torque of the power source, which is being executed at that time, is stopped and a new determination is made. An output torque control device for a vehicle power source, comprising: output torque control updating means for executing a reduction control of an output torque of the power source based on the drive wheel slip.