JP2000009157A - Clutch control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the occurrence of degradation in fuel consumption and vibration, in idling when a vehicle is in a creeping state, and also prevent the vehicle from being backward driven when the vehicle is running over an uphill road. SOLUTION: This clutch control device for a vehicle is formed out of a starting clutch 5 disposed over to the power transmission route starting from an engine over to the wheels, an accel opening sensor 33, a brake fluid pressure sensor 35, a slope sensor 31 detecting the slope of the running surface of a road, and of a vehicle speed sensor 34. When the opening of an accel is found by the accel opening sensor 33 to have been almost closed, and when the vehicle speed is found by the vehicle speed sensor 34 to have been very low or almost suspended, the operation of the clutch 5 is controlled in response to both braking torque BT obtained from the detected value of the brake fluid pressure sensor 35 and the slope of a road surface detected by the slope sensor 31, so that creep torque CT is thereby controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch control device for a vehicle, which controls the operation of clutch means provided in a power transmission system from an engine to wheels to control driving force transmitted to wheels. More specifically, the present invention relates to a clutch control device that controls a driving force, that is, a creep force when an accelerator opening is substantially fully closed and a vehicle is substantially stopped. The accelerator opening is a value corresponding to the throttle opening of the engine, and can be expressed using not only the throttle opening but also the amount of depression of the accelerator pedal.

[0002]

2. Description of the Related Art In an automatic transmission having a torque converter, even when the accelerator is fully closed in a traveling range, the torque from the torque converter driven by the engine idling is transmitted to the wheels to enable creep traveling. It is. On the other hand, in an automatic transmission that does not have a torque converter, control is often performed to enable creep traveling by partially engaging the clutch when the accelerator is fully closed in the traveling range.

In this case, when the vehicle is stopped by stepping on the brake, no creep torque is required, and in this state, the engine consumes extra fuel by the amount of the creep torque to reduce fuel consumption. . There is also a problem that unpleasant engine idle vibration is generated as the engine load increases. For this reason, for example, in Japanese Patent Application Laid-Open No. 1-244930, in an automatic clutch device that generates a creep torque in a traveling range, a brake operation state is detected by a brake switch signal, and the creep torque is reduced when the brake is depressed. It is disclosed to perform the control to make it.

[0004]

A brake switch is mounted to turn on a stop lamp (brake lamp) in conjunction with a brake operation, and the brake pedal is lightly depressed from the viewpoint of safety such as rear-end collision prevention. It is set so that the brake switch is activated and the stop lamp is turned on. On the other hand, the operation of the brake pedal is provided with play, and is usually set so that no brake torque is generated in the first depression stroke of the brake. That is, when the brake pedal is lightly depressed, a state may occur in which the brake switch operates but no brake torque is generated. For this reason,
When the control for reducing the creep torque is performed based on the brake switch signal as described above, the creep torque may decrease even though the brake pedal is lightly depressed but no brake torque is generated.

[0005] The creep torque has the advantage that when the vehicle is stopped on an uphill road and the vehicle is started, the vehicle can be restrained from retreating and the drivability can be improved. On the other hand, the conventional control described above has the following advantages. There's a problem. In order to stop and hold the vehicle without operating the accelerator pedal on an uphill road, the slope resistance torque of the uphill road (torque for moving the vehicle backward according to the gradient) and the hill hold torque (the vehicle is stopped and held) And the desired torque). When the brake pedal is not operated, the creep torque is the hill hold torque as it is, and when the brake pedal is operated, the sum of the creep torque and the brake torque is the hill hold torque.

Here, when the vehicle is stopped when the hill hold torque (= creep torque) and the gradient resistance torque are balanced with the brake pedal released on an uphill road, the conventional brake pedal is depressed. In the control, a control is performed to reduce the creep torque in response to the operation of the brake switch. In this control, the creep torque decreases even when the brake pedal is slightly operated and the brake switch operates, but no brake torque is generated.Therefore, the hill hold torque, which has been balanced with the gradient resistance torque, decreases, and the brake pedal is released. There was a case where a trouble occurred in which the vehicle retreated unexpectedly due to stepping on the vehicle.

The present invention has been made in view of such a problem.
When the vehicle is stopped by stepping on the brake in the driving range, the fuel efficiency is reduced by generating creep torque, and the problem of the vehicle moving backward on an uphill road while reliably preventing the occurrence of engine idling vibration. It is an object of the present invention to provide a vehicle clutch control device capable of performing creep running control that does not occur.

[0008]

In order to achieve the above object, a vehicle clutch control device according to the present invention is provided with a clutch means (for example, an embodiment) provided in a power transmission path from an engine to wheels. The starting clutch 5 in the embodiment, the accelerator opening detecting unit (for example, the accelerator opening sensor 33 in the embodiment), the brake torque detecting unit (for example, the brake fluid pressure sensor 35 in the embodiment), and the gradient of the traveling road surface. It has a gradient detecting means (for example, the gradient sensor 31 in the embodiment) for detecting, and a vehicle speed detecting means (for example, the vehicle speed sensor 34 in the embodiment), and the accelerator opening detecting means detects that the accelerator opening is almost fully closed. When it is detected that there is, and when the vehicle speed detecting means detects that the vehicle is in a slow or stopped state,
The operation of the clutch means is controlled in accordance with the brake torque detected by the brake torque detection means and the road surface gradient detected by the gradient detection means, and the driving force transmitted from the engine to the wheels via the power transmission path ( Creep torque).

At this time, the actuation of the clutch means is such that the driving force transmitted to the wheels is reduced as the braking torque is increased, and the driving force transmitted to the wheels is increased as the road surface gradient increases toward the uphill side. Is preferably controlled.

With the control device having such a configuration, when the brake is actuated when the vehicle is almost stopped and the vehicle is in a creep running state with the accelerator fully closed, the brake torque actually generated by the brake operation is reduced. The creep torque is adjusted accordingly, so that the slope resistance torque and the hill hold torque can always be maintained in a balanced state even when stopped on an uphill road, and the vehicle moves backward even in the case of light braking operation. When the vehicle is started by depressing the accelerator pedal from a stopped state, the vehicle can be started smoothly without retreating. Furthermore, since the creep torque is adjusted according to the road slope, the creep torque is set so that the slope resistance torque and the hill hold torque are balanced at any road slope, and the vehicle can be driven without stepping on the brake pedal on an uphill road. It can be held in a stopped state.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a power transmission path of a vehicle having a vehicle clutch control device according to the present invention, in particular, a continuously variable transmission CV mainly including this path.
The configuration of T is shown. This continuously variable transmission CVT is a metal V
This is a belt-type continuously variable transmission using a belt. The belt-type continuously variable transmission CVT includes a metal V-belt mechanism 10 disposed between an input shaft 1 and a counter shaft 2, and a planetary disposed between the input shaft 1 and a drive-side movable pulley 11. It has a gear-type forward / reverse switching mechanism 20 and a starting clutch 5 disposed between the counter shaft 2 and an output-side member (differential mechanism 8 and the like). The input shaft 1 of the continuously variable transmission CVT is connected to an output shaft of the engine ENG via a coupling mechanism CP, and the power transmitted to the differential mechanism 8 is transmitted to left and right wheels (not shown).

The metal V-belt mechanism 10 includes a drive-side movable pulley 11 disposed on the input shaft 1 and a counter shaft 2
It comprises a driven-side movable pulley 16 disposed above and a metal V-belt 15 wound between the pulleys 11 and 16.

The drive-side movable pulley 11 includes a fixed pulley half 12 rotatably disposed on the input shaft 1, and a movable pulley half 13 axially movable relative to the fixed pulley half 12. Consists of Beside the movable pulley half 13, there is a cylinder wall 12 connected to the fixed pulley half 12.
A drive-side cylinder chamber 14 is formed so as to be surrounded by “a”. A hydraulic pressure supplied into the drive-side cylinder chamber 14 generates a side pressure that moves the movable pulley half 13 in the axial direction.

The driven-side movable pulley 16 comprises a fixed pulley half 17 fixedly mounted on the counter shaft 2 and a movable pulley half 18 which is movable relative to the fixed pulley half 17 in the axial direction. On the side of the movable pulley half 18,
A driven-side cylinder chamber 19 is formed surrounded by a cylinder wall 17 a connected to the fixed pulley half 17, and the movable pulley half 18 is moved in the axial direction by hydraulic pressure supplied into the driven-side cylinder chamber 19. A lateral pressure is generated.

Therefore, by appropriately controlling the oil pressure supplied to the cylinder chambers 14 and 19, an appropriate pulley side pressure that does not cause slippage of the belt 15 is set, and the pulley widths of the pulleys 11 and 16 are set. Can be changed, thereby changing the winding radius of the V-belt 15 to change the speed ratio in a stepless manner.

The planetary gear type forward / reverse switching mechanism 20 has a double pinion type planetary gear train. The sun gear 21 is connected to the input shaft 1, the carrier 22 is connected to the fixed pulley half 12, and the ring gear 23 is a reverse brake. 2
7 can be fixedly held. Further, it has a forward clutch 25 capable of connecting the sun gear 21 and the carrier 22, and when the forward clutch 25 is engaged, all the gears 21, 22, 22 are engaged.
23 rotates integrally with the input shaft 1 and the drive-side pulley 11
Are driven in the same direction as the input shaft 1 (forward direction). on the other hand,
When the reverse brake 27 is engaged, the ring gear 23 is fixedly held, so that the carrier 22 is driven in a direction opposite to that of the sun gear 21, and the drive pulley 11 is moved in a direction opposite to the input shaft 1 (reverse direction). Driven.

The starting clutch 5 is a hydraulically operated clutch for controlling power transmission between the counter shaft 2 and the output side member. When engaged, power can be transmitted between the two and the engagement force is controlled. Thereby, the transmission capacity (transmission torque capacity) of the torque transmitted to the wheel side can also be controlled. For this reason, when the starting clutch 5 is engaged, the engine output shifted by the metal V-belt mechanism 10 is transmitted to the differential mechanism 8 via the gears 6a, 6b, 7a, 7b. And transmitted to the other wheels (not shown). When the starting clutch 5 is released (the transmission torque capacity is zero), this power cannot be transmitted, and the transmission is in a neutral state.

The clutch control device according to the present invention performs the creep torque control by controlling the engagement of the starting clutch 5 particularly when the vehicle is almost stopped. The clutch control device is configured as shown in FIG. This device detects an inclination of a road surface on which the vehicle is traveling (that is, an inclination angle in a vertical plane of the vehicle in a traveling direction of the vehicle). This sensor directly detects an inclination angle of the vehicle body with respect to a horizontal plane. However, in this example, the gradient is calculated from the longitudinal acceleration G of the vehicle, and a G sensor is actually used.)
And a select lever sensor 32 that detects a select lever position (particularly, whether or not the vehicle is in a travel range position) that is operated by a driver to select a shift range, and an accelerator opening (engine throttle opening or accelerator pedal depression amount). , A vehicle speed sensor 34 for detecting the running speed of the vehicle, a brake fluid pressure sensor 35 for detecting the brake fluid pressure,
And a controller 30 that receives the detection signals from 1 to 35 and controls the operation of the electromagnetic proportional valve 36. The electromagnetic proportional valve 36 controls the operating oil pressure supplied to the starting clutch 5, and controls the engaging force of the starting clutch 5 by this operating oil pressure control to control the transmission of the driving force from the engine ENG to the wheels.

The control of the engaging force of the starting clutch 5 will be described with reference to FIG. In this control, first, it is determined from the detection signal from the select lever sensor 32 whether or not the current range is a travel range (D range, R range, etc.) (step S1). In the case of the P range), the process proceeds to step S8,
Control in the neutral mode is performed, and the starting clutch 5 is released.

On the other hand, when the vehicle is in the travel range, it is determined from the detection signal of the accelerator opening sensor 33 whether or not the accelerator is fully closed (the state in which the accelerator pedal is released) (step S2), and the accelerator pedal is depressed. If so, the process proceeds to step S5, where it is determined whether or not the vehicle is starting. When the vehicle is starting, control based on the starting mode (specifically, control for engaging the starting clutch according to changes in vehicle speed and accelerator opening) is performed. ) Is performed (step S6), and when the vehicle is not starting, the normal traveling mode is performed and the starting clutch 5 is completely engaged (step S7).

In step S2, the accelerator opening is almost fully closed (the accelerator pedal is released).
Is determined, the current vehicle speed V detected by the vehicle speed sensor 34 is determined to be equal to or lower than the creep determination vehicle speed Vc (step S3). When V> Vc, it means that the vehicle is traveling normally. The control of steps S5 to S7 is performed. On the other hand, when V ≦ Vc, the vehicle is in the creep running state, and the process proceeds to step S4 to perform control in the creep mode. It should be noted that the creep determination vehicle speed Vc is a speed at which the vehicle is stopped or very close to the stop, and is a speed at which it is determined whether or not creep traveling control should be performed. is there.

Next, regarding the control in the creep mode,
This will be described with reference to FIG. In this control, first, the brake fluid pressure BP is detected by the brake fluid pressure sensor 35 (Step S11), and the brake torque BT is calculated from the detected value (Step S12). FIG. 7B shows the relationship between the brake fluid pressure BP and the brake torque BT. As can be seen from this figure, the two are in a proportional relationship and can be calculated based on this relationship. FIG. 7A shows the relationship between the brake pedal depression amount BS and the brake hydraulic pressure BP. For this reason, instead of detecting the brake hydraulic pressure BP, the brake pedal depression amount BS is detected. (A)
It is also possible to calculate the brake torque BT from the relationship of (B) and (B).

Next, it is determined whether or not the brake torque BT calculated in this manner is larger than the operation determination torque BT0 (step S13). If BT ≦ BT0, the process proceeds to step S19 to perform normal creep control described later. . On the other hand, when BT> BT0, the process proceeds to step S14, and it is determined whether the current vehicle speed V is zero, that is, whether the vehicle is currently stopped. When the vehicle is not traveling but traveling, the process proceeds to step S19 to perform normal creep control. The operation determination torque BT0 is a value for determining whether or not the brake operation has been performed. An extremely small torque value is set, and when the brake torque exceeds this value, it is determined that the brake has been operated, and The control is switched (step S13).

When the vehicle is stopped, the acceleration G in the front-rear direction of the vehicle is measured by the G sensor (gradient sensor) 31 (step S15), and the gradient θ of the road surface is calculated from the acceleration G (step S16). The road surface gradient θ calculated in this manner is a switching determination gradient θ0 (a gradient for performing switching determination between the normal creep control and the weak creep control.
(Set in °) is determined (step S17). If θ ≧ θ0, the process proceeds to step S19 to perform normal creep control, and if θ <θ0, the process proceeds to step S18 to perform weak creep control. Do.

The normal creep control performed in accordance with the above flow is to control the engagement capacity of the starting clutch 5 so that a constant drive necessary for performing creep running on a flat road is transmitted to the wheels. This is performed when the brake is not operated, when the vehicle is creeping (when the vehicle is not stopped), and when the road surface gradient is equal to or greater than the switching determination gradient θ0 (when θ> θ0 = 4 °). In this example, the creep torque is the switching determination gradient θ0 (= 4 °).
With the vehicle stopped on the road surface and the brake released,
The magnitude is set to be in proportion to the gradient resistance torque F.

This will be specifically described with reference to FIG.
This diagram schematically shows the torque acting on the vehicle 50 in a state where the vehicle 50 is stopped on an uphill road having a gradient θ.
T represents creep torque, arrow BT represents brake torque, and arrow F represents gradient resistance torque. In the case of the normal creep control, when the gradient θ = 4 ° and the brake torque BT = 0, a torque balanced with the gradient resistance torque F is set as the creep torque CT. That is,
When the vehicle is stopped on a road surface having a gradient of θ = 4 °, the vehicle is kept stopped without operating the brake, and the gradient resistance torque F decreases while the creep torque CT remains constant as the gradient decreases. Transition to creep running state.

On the other hand, the weak creep control is performed as shown in the flow chart of FIG. That is, first, the brake torque BT calculated as described above is read (step S2).
1) The gradient resistance torque F is calculated from the gradient θ obtained as described above (step S22). Then, it is determined whether the total torque (WCT + BT) of the preset weak creep torque WCT (constant value) and the brake torque BT is larger than the gradient resistance torque F (step S23).

In step S23, (WCT + BT)
If it is determined that> F, the process proceeds to step S24, and the creep torque CT is set as the weak creep torque WCT.
The engagement control of the starting clutch 5 is performed so as to obtain the following. This weak creep torque WCT is determined by the above-described step S
This is a value sufficiently smaller (close to almost zero) than the creep torque set in the normal creep control of No. 19, whereby the engine load is reduced, fuel consumption is reduced, and engine idle vibration is also reduced.

On the other hand, in step S23, (WCT
+ BT) ≦ F, the clutch of the starting clutch is generated such that a creep torque such that the hill hold torque (the total torque of the creep torque CT and the brake torque BT) is equal to the gradient resistance torque F is generated. Joint control is performed. Accordingly, when the brake is only lightly applied, a creep torque larger than the weak creep torque WCT is generated, and the vehicle does not move backward.

In this embodiment, the case where the present invention is applied to a belt-type continuously variable transmission has been described. However, the clutch control device of the present invention is not limited to such a transmission, and a clutch for performing power transmission control may be used. The present invention is applicable to other types of continuously variable transmissions and automatic transmissions.

[0031]

As described above, according to the present invention,
When the brake is operated while the vehicle is almost stopped and the vehicle is in creep running with the accelerator fully closed, the creep torque is adjusted according to the brake torque actually generated by this brake operation. Even when the vehicle is stopped, the gradient resistance torque and the hill hold torque can always be maintained in a balanced state. Even in the case of a light brake operation, the vehicle does not move backward and the accelerator pedal is depressed from the stopped state. When the vehicle is started, the vehicle can be started smoothly without retreating. Further, in the state where the brake is operated, the clutch control is performed so as to reduce the creep torque within a range where the vehicle does not retreat, so that the engine load can be reduced, the fuel efficiency can be improved, and the engine idle vibration can be reduced. .

Further, since the creep torque is adjusted according to the road surface gradient, the creep torque is set so that the gradient resistance torque and the hill hold torque are balanced at any road surface gradient, and the brake pedal is not depressed on an uphill road. Can also hold the vehicle in a stopped state.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a power transmission path of a vehicle having a clutch control device according to the present invention.

FIG. 2 is a block diagram showing a configuration of a clutch control device according to the present invention.

FIG. 3 is a flowchart showing control contents by the clutch control device.

FIG. 4 is a flowchart showing control contents by the clutch control device.

FIG. 5 is a flowchart showing control contents by the clutch control device.

FIG. 6 is a schematic diagram showing directions of creep torque, brake torque and gradient resistance torque when the vehicle body is on an uphill road.

FIG. 7 is a graph showing a relationship between a brake pedal depression amount and a brake fluid pressure, and a relationship between a brake fluid pressure and a brake torque.

[Explanation of symbols]

 5 Start clutch 30 Controller 31 Gradient sensor (G sensor) 33 Accelerator opening sensor 34 Vehicle speed sensor 35 Brake fluid pressure sensor

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Claims (2)

[Claims] 1. A clutch disposed in a power transmission system from an engine to wheels, an accelerator opening detector for detecting an accelerator opening, a brake torque detector for detecting a brake torque, and a vehicle traveling road surface. And a vehicle speed detecting means for detecting a running speed of the vehicle. The accelerator opening detecting means detects that the accelerator opening is substantially fully closed, and the vehicle speed detecting When the vehicle is detected to be in a slow or stopped state by the means, the operation of the clutch means is performed in accordance with the brake torque detected by the brake torque detecting means and the road surface gradient detected by the gradient detecting means. A vehicle clutch control device for controlling. 2. The driving force transmitted to the wheel decreases as the brake torque detected by the brake torque detecting means increases, and the driving force transmitted to the wheel increases as the gradient detected by the gradient detecting means increases toward the uphill side. 2. The vehicle clutch control device according to claim 1, wherein the operation of the clutch unit is controlled so as to increase the transmitted driving force.