JPH11336890A - Control device for vehicular transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device which executes hill hold control when a vehicle is started over an uphill road without impairing power performance or drivability. SOLUTION: This control device for a vehicular transmission 100 is equipped with a hill hold means 102 which selectively prevents a rotation member connected with each driving wheel 101 from being rotated out of a rotation suspended condition to the rotation to the backward running direction, and the device is equipped with a detection means 103 detecting the easy slipping of each driving wheel 101, and with a hill hold execution means 104 allowing the hill hold means 102 to prevent the rotation member from being rotated out of a rotation suspended condition to a rotation to the backward running direction when the easy slipping of each driving wheel is detected by the detection means 103.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle transmission capable of executing a so-called hill hold for preventing a vehicle from moving backward when starting on an uphill road.

[0002]

2. Description of the Related Art When a vehicle is started, normally, release of a brake and depression of an accelerator pedal are continuously performed. Therefore, when braking is performed by depressing the brake pedal, the driving force decreases from the time when the brake pedal is released to the time when the accelerator pedal is depressed and the driving force increases. In a vehicle equipped with a manual transmission, the driving force is substantially zero because the clutch is released at that time, and in a vehicle equipped with an automatic transmission, only a creep torque is obtained.
Therefore, when starting on an uphill road, the driving torque may be insufficient and the vehicle may temporarily move backward.

[0003] A control device capable of executing a so-called hill hold for preventing such a backward movement at the time of starting on an uphill road is disclosed in Japanese Utility Model Laid-Open No. 2-56965. The device described in this publication is a control device intended for an automatic transmission, which sets a high speed stage when starting from a stopped state in order to prevent creeping start, and goes uphill due to a shortage of driving torque accompanying the setting. The reverse movement of the vehicle on the road is configured to be prevented by engaging the one-way clutch. That is, the high-speed gear set at the time of start on the uphill road is configured to be the gear that the one-way clutch that locks at the low-speed gear releases.

[0004]

According to the apparatus described in the above-mentioned publication, when the vehicle starts moving on an uphill, the driving torque becomes insufficient and the vehicle tries to move backward by its own weight, the torque to the automatic transmission is reduced. The input direction is opposite to that during normal running, so that the one-way clutch is engaged. As a result, rotation of a predetermined rotating element constituting the automatic transmission, that is, backward movement of the vehicle is prevented. . However, the gear set at that time is a gear higher than the low gear (generally the first gear) set at the time of normal start, so that the driving torque is smaller than at the time of normal start. I have to be. In particular, the driving resistance is high due to the uphill road, so the feeling of lack of driving torque due to the high speed stage increases, and the power performance and drivability may be impaired, such as the inability to obtain the intended acceleration. There is.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device for a vehicle transmission which has a hill hold function and can obtain a sufficient driving force as required. It is the purpose.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention executes hill hold only when a driving wheel is liable to slip, and otherwise executes hill hold. , The driving torque is controlled so as to increase, and the driving torque is increased to prevent the vehicle from moving backward and improve the power performance. More specifically, the present invention relates to a control device for a vehicle transmission provided with hill hold means for selectively preventing rotation of a rotating member connected to drive wheels from a rotation stop state in a reverse traveling direction, Detecting means for detecting that the driving wheel is likely to slip; and, when the detecting means detects that the driving wheel is likely to slip, the hill hold means for changing the rotation of the rotating member from the stop state to the reverse traveling direction. A hill hold executing means for preventing rotation.

Therefore, according to the control device of the present invention,
When a state in which the driving wheels easily slip is detected, the hill hold means prevents the rotation of the rotating member in the backward traveling direction, and the hill hold is performed. On the other hand, if a state in which the drive wheels are likely to slip is not detected,
The rotation of the rotating member in the backward traveling direction is allowed. That is, hill hold is not performed. Therefore, unless the driving wheels are likely to slip, the driving torque is increased by increasing the output of the power source by depressing the accelerator pedal or the like, so that the intended power performance can be obtained. If the system is configured to perform hill hold by setting a high-speed gear,
Since the drive wheels are unlikely to slip, the low-speed stage is set at the time of starting, so that the drive torque also increases at this point and the power performance is not impaired.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be specifically described with reference to the drawings. FIG. 1 shows the principle of the present invention, in which an output member of a transmission 100 is connected to driving wheels 101. The transmission 100 is for shifting the input torque and outputting the transmission. The most typical example is an automatic transmission for a vehicle, which can set a plurality of forward gears. In addition to a step-type automatic transmission and a continuously variable transmission that can continuously change the gear ratio, a manual transmission may be used. In the case of a stepped transmission, one of the rotating members such as a gear and a shaft is driven by the driving wheel 1 according to the set shift speed.
01 and the other rotating members are not connected to the driving wheels.

A hill hold means 102 is provided for holding the vehicle from moving backward when the vehicle starts moving.
The hill hold means 102 is used to drive the driving wheels 10
Means for setting a high-speed stage for freeing the one-way clutch engaged by the rotation in the reverse running direction, the means being adapted to prevent rotation of the rotary member connected to the first reverse direction. Appropriate configuration such as a means for operating a one-way clutch specially provided for holding may be employed.

[0010] The control device according to the present invention includes a drive wheel 1.
Detecting means 103 for detecting a state where 01 is likely to slip
It has. This detecting means 103 is means for estimating the friction coefficient μ of the road surface based on the vehicle speed and data obtained from the anti-lock brake system (ABS), or at the time of a high speed gear such as the second speed at the time of snowfall or snowy road. For example, means for detecting that the snow mode in which the vehicle starts to start is selected may be employed.

A hill hold executing means 104 is provided which causes the hill hold means 102 to execute hill hold control when the detecting means 103 detects that the drive wheel 101 is likely to slip. That is, low μ
When the driving wheels 101 are likely to slip on a road or the like, the hill hold executing means 104 outputs a signal to execute hill hold control such as setting a predetermined high speed stage.

More specifically, FIG. 2 shows a control system diagram of the engine 1 and the automatic transmission 2 in which a signal corresponding to the depression amount of the accelerator pedal 3 is generated. It is input to the engine electronic control unit 4. An electronic throttle valve 6 driven by a throttle actuator 5 is provided in an intake pipe of the engine 1. The electronic throttle valve 6 outputs a control signal from the electronic control unit 4 to the throttle actuator 5 in accordance with the depression amount of the accelerator pedal 3, and the opening degree is controlled in accordance with the control amount.

An electronic control unit 4 for controlling the engine 1 includes a central processing unit (CPU) and a storage unit (R).
AM, ROM) and an input / output interface. The electronic control unit 4 includes, in addition to a signal corresponding to the depression amount of the accelerator pedal 3 described above,
Output signal of engine speed sensor 7, output signal of intake air flow center (air flow meter) 8, output signal of intake air temperature sensor 9, output signal of throttle opening sensor 10, output signal of vehicle speed sensor 11, cooling water Temperature sensor 1
2 and the output signal of the brake switch 13 are input as control data. In addition to the control of the throttle actuator 5, the engine electronic control unit 4 outputs a signal to the fuel injection device 14, an igniter 15 for changing the ignition timing, and the like for torque control at the time of gear shifting or the like. It is configured.

The automatic transmission 2 connected to the engine 1 is a so-called electronically controlled automatic transmission that electrically controls the hydraulic pressure to control shifting and engagement / disengagement of a lock-up clutch. The hydraulic control circuit 16 for controlling the hydraulic pressure mainly includes three shift solenoid valves SOL1, SOL2, and SOL3 for executing a shift, a linear solenoid valve SLU for mainly controlling a lock-up clutch, and a throttle opening degree. A linear solenoid valve SLT for controlling the line pressure and a linear solenoid valve SLN for mainly controlling the back pressure of the accumulator are provided.

An electronic control unit 17 for an automatic transmission for outputting a control signal to each solenoid valve in the hydraulic control circuit 16 is provided. The electronic control unit 17 for the automatic transmission includes a central processing unit (CPU) and a storage unit (RA), like the electronic control unit 4 for the engine.
M, ROM) and an input / output interface, and therefore can be integrated with the engine electronic control unit 4 as necessary. The electronic control unit 17 for the automatic transmission performs a calculation based on input data in accordance with a map or a calculation formula stored in advance, and outputs a control signal based on the calculation result to each of the solenoid valves to shift or lock up. It is configured to execute control of engagement / disengagement of a clutch, control of transient hydraulic pressure during gear shifting, and the like.

The electronic control unit 17 for the automatic transmission stores the throttle opening sensor 1 as control data as control data.
0, the output signal of the vehicle speed sensor 11, the output signal of the coolant temperature sensor 12, the output signal of the brake switch 13, the signal from the shift position sensor 19 provided in the shift device 18, the torque converter described later. , A signal from a kick down switch 21 that is turned on when the accelerator pedal 3 is fully depressed, a signal from a pattern select switch 22 for selecting a power mode, a normal mode, or a snow mode, and the like. Is entered. The electronic control units 4 and 17 are connected so as to be able to communicate with each other, and a signal for setting each gear is transmitted from the electronic control unit 17 for the automatic transmission to the electronic control unit 4 for the engine. ing.

The automatic transmission 2 has four forward speeds and one reverse speed.
The gear stage can be set, and an example of the gear train is shown in FIG. The gear train shown here is the same as that described in Japanese Patent Application Laid-Open No. Hei 4-185967, and the automatic transmission 2 includes a lock-up clutch Lc
, A second transmission section G2 having a set of planetary gear mechanisms, and a first transmission section G1 for setting a plurality of forward speeds and reverse speeds by two sets of planetary gear mechanisms.
And

The second speed change section G2 performs high-low two-stage switching, and the carrier 27 of the planetary gear mechanism uses the turbine runner Tr of the torque converter Tc.
And the carrier 27 and the sun gear 2
8, a clutch C0 and a one-way clutch Fo are provided in a mutually parallel relationship, and a brake B0 is provided between the sun gear 28 and the housing Hu.

The sun gears 29 and 30 in each planetary gear mechanism of the first transmission portion G1 are provided on a common sun gear shaft 31, and the left (front side) planetary gear mechanism of the first transmission portion G1 in the drawing. Ring gear 32 and second
A first clutch C1 is provided between the transmission gear G2 and the ring gear 33, and a second clutch C2 is provided between the sun gear shaft 31 and the ring gear 33 of the second transmission G2. In the first transmission portion G1, the carrier 34 of the planetary gear mechanism on the left side in the figure and the ring gear 35 of the planetary gear mechanism on the right side (rear side) are integrally connected,
The output shaft 36 is connected to the carrier 34 and the ring gear 35.
Are connected.

A first brake B1 as a band brake is provided on the outer peripheral side of the clutch drum of the second clutch C2 so as to stop the rotation of the sun gear shaft 31. Hu, a first one-way clutch F1 and a second brake B2 are arranged in series, and a second one-way clutch F2 and a housing Hu between the carrier 37 and the housing Hu in the rear planetary gear mechanism. The third brake B3 is arranged in parallel.

Automatic transmission 2 provided with the above gear train
Can be set to four forward speeds and one reverse speed, and the engaged and released states of the clutch and brake for setting each speed are as shown in FIG. In FIG. 4, a circle indicates engagement, and a blank indicates a released state. Also, P, R,
Each character of N, D, 2, and L indicates a shift range.
Therefore, in the first speed and the second speed in the drive (D) range selected in the normal traveling, the one-way clutches F1, F
If the driving torque is insufficient when the vehicle starts on an uphill road, the one-way clutches F1 and F2 are released, so that the hill hold function cannot be obtained. On the other hand, in the third speed, the entire gear train is integrated, so that the hill hold function can be operated.

The automatic transmission 2 is basically based on data indicating a running state such as an engine load represented by a throttle opening, a turbine speed or a vehicle speed, and a shift map stored in advance. Thus, the shift speed to be set is determined, and the shift is executed. That is, if the vehicle speed is low, the lower gear position is set, and the higher gear position is set as the vehicle speed increases or the engine load decreases.
On the other hand, on a so-called low μ road where slipping of the drive wheels easily occurs, the hill hold control is executed, and the third speed is set even at the time of starting. FIG. 5 is a flowchart for explaining an example of the control.

In FIG. 5, while initial processing such as data reading is performed, it is determined whether or not the traveling road is a low μ road (step 1). This can be determined, for example, based on the fact that the signal from the pattern select switch 22 indicates the snow mode. Although not specifically shown, the determination may be performed by estimating a road surface friction coefficient based on a vehicle speed, a signal from an antilock brake system, or the like. The function of step 1 corresponds to the detecting means of the present invention.

If it is determined that the road is a low μ road, hill hold control is executed (step 2). The hill hold control is a control for setting the state of the automatic transmission 2 so that the vehicle does not move backward when the vehicle starts moving. Therefore, when the vehicle is stopped, the third
Speed is set. As described above, in the third speed, the entire gear train of the gear transmission is integrated, so that the gears or rotating elements connected to the drive wheels are maintained in a fixed state, and the vehicle is prevented from moving backward. Step 2 corresponds to the hill hold executing means of the present invention.

Conversely, if the low μ road is not determined, the hill hold control is prohibited (step 3).
That is, the shift control is executed according to the vehicle speed and the throttle opening, and the first speed is set when the vehicle is stopped.

Therefore, in the control shown in FIG. 5, the hill hold control is executed based on the determination of the low μ road, and therefore, for example, even on an uphill road, if the snow mode is not selected and the road surface friction coefficient is large, If it is determined, the hill hold control is not performed. That is, the first speed is set at the time of starting. As a result, the creep torque is increased by changing the operation of the brake pedal and the accelerator pedal, by using the side brake, or by increasing the speed ratio of the first speed, thereby increasing the creep torque on an uphill road. You can prevent retreating at the time of starting,
In addition, the driving torque at the time of starting increases, and sufficient starting acceleration performance can be obtained. In this case, even if the accelerator pedal is depressed greatly, the road surface friction coefficient is large, so that the driving wheels hardly slip, so that the vehicle can be prevented from moving backward and stable starting can be performed.

Next, a description will be given of control after the vehicle starts while hill hold control is being executed. When the vehicle is started with the high-speed gear set as described above, the accelerator pedal is often depressed greatly in order to increase the engine output due to the small gear ratio, and the oil (fluid) in the automatic transmission 2 is accordingly increased. ) Agitation becomes intense,
As a result, an increase in oil temperature may be a problem. Therefore, after starting in the hill hold control state, control is performed as shown in FIG.

That is, FIG. 6 shows a control example when the snow mode is selected and the shift range in which the high speed gear for the hill hold control can be set is selected. Do (Step 1
1). This flag F is a flag that is set to “1” when the hill hold control is executed as described later. If the flag F is not “1” because the hill hold control is not executed, It is determined whether the vehicle has stopped (step 12). If the vehicle is running, normal shift control, that is, shift control based on data such as the engine load and the vehicle speed or the turbine speed is performed, and the current shift stage is maintained (step 13). On the other hand, if the vehicle is stopped, the high speed stage, ie, the third speed, at which hill hold is possible is set because the snow mode is selected (step 14). Then, the flag F is set to "1" (step 15).

The hill hold control is executed as described above. As a result, when it is determined in step 11 that the flag F is set to "1", it is determined whether or not the vehicle has started. Step 16). This can be determined, for example, based on whether the vehicle speed has increased from zero. If the vehicle has been stopped, the process proceeds to step 14 to maintain the high gear.

On the other hand, if it is determined in step 16 that the vehicle has started, the vehicle shifts down to a low gear (step 17). The low gear may be a gear determined based on the engine load or the vehicle speed at that time, or may be a predetermined gear such as a first gear. In addition, the determination of the start of the vehicle is set as a reference vehicle speed with a somewhat high vehicle speed, the high gear for hill hold is maintained until the detected reference vehicle speed is exceeded, and then the downshift to the low gear is performed. It may be that. Further, the downshift to the low-speed gear may be delayed for a fixed time by timer control. That is, a delay means for downshifting to a lower speed stage may be provided. When the control in step 17 is executed, the flag F is set to "0" (step 18).

Therefore, according to the control shown in FIG. 6, it is possible to prevent the vehicle from traveling in the high-speed gear for a long time in the traveling state in which a large driving torque is required.
As a result, a situation such as an increase in oil temperature in the automatic transmission 2 can be prevented.

In the specific example described above, an example is shown in which the third speed is set as the hill hold speed, but other speeds, such as a fourth speed without using a one-way clutch or a second speed in which engine braking is effective, are described. The gear stage may be a gear stage for hill hold. Therefore, the hill hold means of the present invention can be used as a means for setting the high speed stage at the time of starting. Further, the present invention can be applied to a transmission configured to prevent the vehicle from retreating at the time of starting by means other than hill hold control by setting a high speed stage. The present invention can be applied to a target control device.

[0033]

As described above, according to the control device of the present invention, the hill hold control is executed when it is detected that the driving wheels are likely to slip, so that the slope of the road surface has a low coefficient of friction. The vehicle can be started smoothly on the road, and on uphill roads where driving wheels are unlikely to slip, such as on dry paved roads, the driving torque increases by increasing the output of the power source such as the engine, Necessary and sufficient start acceleration can be obtained, and drivability and power performance can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing in principle an example of a control device according to the present invention.

FIG. 2 is a system diagram more specifically showing a control system in an example of the control device according to the present invention.

FIG. 3 is a skeleton diagram showing a gear train of the automatic transmission.

FIG. 4 is a table showing engagement and disengagement states of a clutch and a brake for setting each shift speed in the automatic transmission.

FIG. 5 is a flowchart illustrating an example of control by a control device according to the present invention.

FIG. 6 is a flowchart for explaining another example of control by the control device according to the present invention.

[Explanation of symbols]

2: Automatic transmission 17: Electronic control unit for automatic transmission
22: pattern select switch, 100: transmission, 101: drive wheel, 102: hill hold means,
103: detecting means; 104: hill hold executing means.

Claims (1)

[Claims] 1. A control device for a vehicle transmission comprising a hill-hold means for selectively preventing rotation of a rotating member connected to a drive wheel in a reverse running direction from a rotation stop state, wherein the drive wheel slips Detecting means for detecting that the driving wheel is likely to slip; and a hill for preventing rotation of the rotating member in a reverse traveling direction from a rotation stop state of the rotating member when the detecting means detects that the driving wheel is likely to slip. A control device for a vehicle transmission, comprising: a holding unit.