JPH0560222A - Automatic transmission - Google Patents

Abstract

PURPOSE:To use a lock-up mechanism effectively even at the time of stopping and starting by providing a control means for turning a lock-up clutch on to make a torque converter ineffective and for controlling the oil pressure of an oil pressure control valve in response to the depression quantity of an accelerator pedal to start under the stop condition. CONSTITUTION:When an intension to of stop is expressed, a CPU turns an oil pressure control valve 9 on, and a manual valve 5 is switched to the N range condition. Furthermore, when the output signal of a speed sensor 11 is input and the speed is at about 0km/h, the CPU 10 turns a solenoid valve 3 on. A lock-up clutch 4 is thereby tuned on to make a torque converter ineffective. Thereafter, when the CPU 10 inputs the output signal of a throttle sensor 12 again and operation of an acceleration pedal is judged, since the speed is switched from the stop condition to the starting condition, operation quantity of the oil pressure control valve 9 at an open degree of the accelerator at this stage is decided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission,
In particular, it relates to an automatic transmission having a torque converter.

[0002] In recent years, many vehicles have been equipped with automatic transmissions in order to improve driving and running, and among them, the number of vehicles running and running using a torque converter has been increasing. ..

On the other hand, a vehicle equipped with such a torque converter has a large loss of transmission driving force. Therefore, when the vehicle speed and the gear stage are constant, the torque converter is bypassed and the engine output and the transmission are separated. A lock-up mechanism that directly connects

FIG. 6 schematically shows an automatic transmission having such a lock-up mechanism. In the figure, 1 is an oil pump and 2 is a pressure valve for distributing the oil pressure from the oil pump 1. 3 is the pressure valve 2
Solenoid valve for turning on / off (opening / closing) the hydraulic pressure distributed to the lockup (L / U) clutch 4 from the pressure valve 2 and the hydraulic pressure distributed from the pressure valve 2 to a shift lever (select lever) of the vehicle and a manual operation. It is a manual valve that interlocks with the hydraulic circuit 6 to switch the hydraulic pressure to the transmission gear unit 7.

In the operation of such an automatic transmission, when the shift lever is moved from the N range to the D range or from the P range to the D range, the manual valve 5 works in conjunction with this to operate the hydraulic pressure. The hydraulic pressure advances to the D port of the circuit 6, and this hydraulic pressure connects a planetary gear clutch (not shown) to automatically select the gear of the transmission gear unit 7, which corresponds to the vehicle speed and the depression amount of the accelerator pedal at that time. Gears are available.

The control oil pressure of the transmission gear unit 7 is distributed from the pressure valve 2, and the oil pressure is distributed from the pressure valve 2 to the lockup clutch 4 via the solenoid valve 3. When the vehicle runs at a constant gear and at a constant speed, the solenoid valve 3 is turned on by a control signal from a control unit (not shown) and the lockup clutch 4 is activated by the hydraulic pressure from the pressure valve 2. Is operated to disable the torque converter (not shown) to eliminate the loss of the transmission driving force by the torque converter.

[0007]

However, in the automatic transmission having the torque converter as described above, even when the vehicle has a lock-up mechanism, when the vehicle runs at a constant gear speed and a constant speed. Since it only operates, a creep phenomenon (unconscious start) occurs when the vehicle is stopped, and the engine idle speed must be increased while suppressing the creep phenomenon, which leads to poor fuel consumption. When the vehicle starts, the torque converter slips. There is a problem in that the engine must be driven at a high rotation speed in consideration of the above.

Therefore, an object of the present invention is to make it possible to effectively use the lock-up mechanism in an automatic transmission having a torque converter even when the vehicle is stopped or started.

[0009]

In order to solve the above problems, the automatic transmission according to the present invention comprises a vehicle speed detecting means,
Accelerator depression amount detection means, brake operation detection means,
A hydraulic control valve that is inserted between a manual valve and a pressure valve that controls the hydraulic pressure to the manual valve to control the hydraulic pressure to the manual valve, and the output signal of each detection means are input to allow the vehicle to stop. When detected, the hydraulic control valve is controlled to cut off the hydraulic pressure to the manual valve. At this time, if the vehicle speed detected by the vehicle speed detecting means indicates a stopped state, the lockup clutch connected to the pressure valve is turned on. And a control means for disabling the torque converter and controlling the hydraulic pressure of the hydraulic control valve according to the subsequent accelerator depression amount to start.

Further, when controlling the hydraulic pressure to the manual valve in accordance with the accelerator depression amount, the control means is arranged to increase the hydraulic pressure to the manual valve temporally for the same accelerator depression amount. The output hydraulic pressure of the hydraulic control valve can be controlled to 100%.

Further, when the hydraulic pressure to the manual valve is cut off, the control means controls the hydraulic pressure control valve to control the hydraulic pressure control valve when the output signal of each detection means indicates that the vehicle is not stopped and the vehicle is ready to start. Output hydraulic pressure to
It can be 100%.

[0012]

In the present invention, the hydraulic control valve is provided between the pressure valve and the manual valve, which are usually equipped in the automatic transmission, and the control means inputs the output signals of the respective detection means and outputs them from these output signals. When the intention to stop the vehicle is detected, the hydraulic control valve is controlled to cut off the hydraulic pressure from the pressure valve to the manual valve to bring the manual valve into the N range state.

At the same time, when the vehicle speed detected by the vehicle speed detecting means indicates a stopped state, the control means turns on the lockup clutch connected to the pressure valve to invalidate the torque converter, and directly drives the engine driving force to drive the engine. Send to the system.

After that, when the accelerator pedal is depressed to indicate the intention to start, the control means controls the hydraulic pressure of the hydraulic control valve according to the accelerator depression amount detected by the accelerator depression amount detecting means. Therefore, since the hydraulic pressure of the manual valve also changes in accordance with the change of the output hydraulic pressure of the hydraulic control valve, the automatic shift operation corresponding to this hydraulic pressure can be realized and the vehicle can be started smoothly.

In this way, when the vehicle is stopped or started, the control hydraulic pressure of the transmission gear unit is directly controlled by the hydraulic control valve without using the torque converter, and the planetary gear clutch system of the main value of the manual mission vehicle is used. It is possible to eliminate the creep phenomenon and high idle rotation.

Further, in the present invention, when the control means controls the hydraulic pressure to the manual valve according to the accelerator depression amount, the hydraulic pressure to the manual valve increases with time for the same accelerator depression amount. As described above, the output hydraulic pressure of the hydraulic control valve is controlled to 100%, that is, until the pressure valve and the manual valve are directly connected, and normal shift control can be performed with the lockup clutch functioning. To do so.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of an automatic transmission according to the present invention. In the figure, the same reference numerals as those in FIG. 6 designate the same or corresponding parts. In the present invention, the hydraulic control valve 9 is provided between the pressure valve 2 and the manual valve 5.
The hydraulic control valve 9 is controlled by a control signal from a CPU 10 as a control means.

The CPU 10 receives the output signals of the vehicle speed sensor 11, the throttle (accelerator opening) sensor 12, and the brake switch 13 and sends the control signal to the hydraulic control valve 9 as described above, and at the same time, the hydraulic circuit 6 and the solenoid. A control signal is also given to the valve 3. still,
An idle detection switch may be used instead of the throttle sensor.

Further, in this embodiment, a hydraulic cylinder 41 is provided between the solenoid valve 3 and the lockup clutch 4.
A hydraulic control unit 40 including a hydraulic piston 42 and a hydraulic piston 42 is provided. When the solenoid valve 3 is turned on and the control hydraulic pressure from the pressure valve 2 is applied to the hydraulic control unit 40, the hydraulic piston 42 is pressed. As a result, the working oil pressure from the pressure valve 2 is applied to the lockup clutch 4 and turned on (lockup working state), and the working oil is returned to the oil drain.

Further, similarly to the hydraulic pressure control unit 40, the hydraulic circuit 6 to which the working hydraulic pressure from the pressure valve 2 is supplied.
In this embodiment, the speed change gear unit 7 connected to is connected to the shift gear unit 7 includes seven clutches CL to hydraulic pressure by hydraulic pressure from the hydraulic pressure output ports 21 to 24 of the manual valve 5 which is interlocked with the shift lever 8 by a wire or a link shaft. A desired gear is obtained by combining some of the predetermined clutches CL through the circuit 6. The known relationship between the range of the shift lever 8 and the output port of the manual valve 5 in this case is shown in FIG.

FIG. 3 shows the transmission gear unit 7 and the PT shown in FIG.
This shows a well-known connection relationship between the O output system and the torque converter system. Power from the engine is transmitted from the input shaft 10 to the transmission gear unit 7 via the torque converter TC or the lockup clutch 4, and the transmission gear unit 7 is transmitted. The power is obtained from the output shaft 30 by appropriately selecting the gear clutch out of 7. In the figure, the torque converter TC includes an impeller TC2 on the engine side, a stator TC3 connected to an oil pump OP, and a turbine section TC1 on the transmission side, and PG1 to PG3 are controlled by a hydraulic circuit 6. The planetary gears controlled by hydraulic pressure to select a gear stage corresponding to the control hydraulic pressure are shown. OC1 to OC4 are planetary gears PG1 to P4.
Although a one-way clutch that idles only in one direction is shown to provide the desired engagement state of G3, detailed operations thereof are omitted here.

CPU 1 in such an automatic transmission
The control algorithm of 0 is shown in FIG. 4, and the operation of FIGS. 1 and 3 will be described below along the flow of FIG.

First, the CPU 10 reads the output signal of the vehicle speed sensor 11, and this vehicle speed is the lowest vehicle speed V at which the idle speed of the engine can be maintained (at the first gear and the transmission ratio of 100%).
It is determined whether the _IDL is exceeded (step S1).
This is to determine whether or not the vehicle is about to shift to the stopped state. When the vehicle speed exceeds this minimum vehicle speed V _IDL , the following control is not performed and this step S1 is repeated until the vehicle speed falls below the minimum vehicle speed V _IDL , CPU when
10 is a throttle sensor (or an idle detection switch)
It is determined from an output signal of 12 whether the accelerator pedal (not shown) is depressed (on) or not (off) (step S2), and the brake switch 13 is released at the time when the driver's foot is separated from the accelerator pedal (off). Is input to determine whether the state of the brake switch 13 is on or off (step S3), and when the brake pedal (not shown) is not depressed and the brake switch 13 is off. The process returns to step S2, but when the brake switch 13 is turned on due to depression,
Steps S1 to S3 indicate that the intention to stop the vehicle is detected.

In this way, when the intention to stop is indicated,
The CPU 10 turns on the hydraulic control valve 9 (step S4). This “on” refers to a state in which the hydraulic control valve 9 completely shuts off the hydraulic pressure from the pressure valve 2 and does not apply it to the manual valve 5. As a result, the manual valve 5 is brought into the N range state, as shown in FIG.
Since a predetermined hydraulic pressure is not applied to the speed change gear unit 7, the driving force from the engine is not applied from the input shaft 10 to the output shaft 30 and the vehicle cannot run.

Further, the output signal of the vehicle speed sensor 11 is input to determine whether the vehicle speed is approximately 0 km / h, that is, whether the vehicle is stopped (step S5).

When the vehicle speed is approximately 0 km / h, the CPU 10 turns on the solenoid valve 3 to turn on the lockup clutch 4 (step S).
6). As a result, the lockup clutch 4 is activated, the torque converter TC (FIG. 3) is disabled, and the engine output is transmitted from the input shaft 10 to the output shaft 30 via the lockup clutch 4. However, at this time, since the hydraulic pressure is not applied to the manual valve 5,
The transmission gear unit 7 has not yet transmitted the driving force to the output shaft 30.

After that, the CPU 10 again inputs the output signal of the throttle sensor 12 and determines whether or not the accelerator pedal is depressed (step S7). When it is found that the accelerator pedal is depressed (ON), Since the vehicle has changed from the stopped state to the start state, the accelerator opening (throttle opening) at this time is detected / determined (step S
8).

This detection / judgment is carried out in the range of 0 to 1 of accelerator opening.
The operation amount of the hydraulic pressure control valve 9 at each accelerator opening is determined at every 10% at 00% (step S9).

That is, as shown in FIG. 5 (a), the operation amount of the hydraulic control valve 9 is determined according to the characteristic curve A when the accelerator opening is 10% or less, and when it is 10% to 20%. The operation amount of the hydraulic control valve 9 is determined according to the characteristic curve B, and when it is 20% to 30%, the operation amount of the hydraulic control valve 9 is determined according to the characteristic curve C.
In the case of 100%, the operation amount of the hydraulic control valve 9 is determined according to the characteristic curve J. The horizontal axis of this graph is the time axis because the operation amount increases with time when the accelerator opening is constant.

Further, FIGS. 9B and 9C show changes in the characteristic curve when the accelerator opening is changed. As shown in FIG. 9B, the accelerator opening increases with time. If this happens, the operation amount of the hydraulic control valve 9 will increase with time as shown in FIG. The operation amount of the hydraulic control valve 9 can be controlled by duty ratio control. Also, the characteristic curves of (a) to (c) in the figure are CP
It is stored as a map in the memory of U10 (FIG. 1).

In this way, the operation amount of the hydraulic control valve 9 is determined according to the depression amount of the accelerator pedal, so that the hydraulic pressure is applied to the manual valve 5 by the operation amount. Then, in the manual valve 5 which receives the hydraulic pressure corresponding to this operation amount, the hydraulic pressure is transferred to the hydraulic circuit 6
Is applied to the shift gear unit 7, the shift gear unit 7 controls the planetary gears PG1 to PG3 shown in FIG. 3 to form a gear stage corresponding to the hydraulic pressure thereof, that is, the depression amount of the accelerator pedal to form the lockup clutch. The driving force from 4 is transmitted to the output shaft 30.

After step S9, the CPU 10 determines whether the accelerator opening is in the increasing direction (step S1).
0), when it is found that it is in the decreasing direction, the process returns to step S7, but when it is in the increasing direction, it is determined whether or not the control hydraulic pressure of the hydraulic control valve 9 has become maximum (step S11). This is because the operation amount of the hydraulic control valve 9 increases with time as shown in FIG. 5 (a), so that the vehicle speed gradually increases even if the starting state progresses and the accelerator opening is constant, for example. Although the steps S8 to S11 are repeated during this period, the maximum operation amount, that is, the output hydraulic pressure of the hydraulic control valve 9 is not directly controlled and the pressure valve 2 and the manual valve 5 are directly connected. In this state (Yes in step S11), the process returns to step S1 to continue the starting operation.

In this way, the lockup clutch 4 is engaged from the stopped state, and the control oil pressure corresponding to the accelerator opening is applied to the manual valve 5 when the starting state is detected, so that the planetary gear of a normal manual transmission can be obtained. Can be used as a substitute for the torque converter.

Returning to FIG. 4, when the depression of the accelerator pedal is not detected in step S7, the state of the brake switch 13 is detected (step S12), and the brake is locked only when the vehicle is in the stop intention state. The up clutch 4 is turned off (step S13), the torque converter TC is once enabled, and the process returns to step S4.

In step S5, the vehicle speed is 0 km.
/ H, the brake switch 1
The state of No. 3 is determined (step S14), and when the brake switch 13 is off and the brake pedal is not depressed, it is determined whether or not the accelerator pedal is depressed (step S15). Therefore, the hydraulic control valve 9 whose power has been shut off in step S4 is turned off (100%) and the process returns to step S1.

[0036]

As described above, according to the present invention, the hydraulic control valve is provided between the pressure valve and the manual valve, and when the intention to stop the vehicle is detected, the hydraulic control valve is controlled to control the hydraulic pressure to the manual valve. If the vehicle is in a stopped state at this time, the lockup clutch is turned on to invalidate the torque converter, and the hydraulic pressure of the hydraulic control valve is controlled according to the subsequent accelerator depression amount to be applied to the manual valve. Since the torque converter is not used when the vehicle is stopped or started, the creep phenomenon is eliminated and the safety is improved.

Further, when the vehicle is stopped, the engine speed can be reduced to a speed equivalent to that of a manual vehicle, and fuel consumption can be improved.

Furthermore, since the engine power is cut off by the hydraulic control valve when the vehicle is stopped in the D range, vibration and noise from the engine can be reduced. In addition, since the planetary gear clutch can be program-controlled by the control means, the power transmission rate can be changed,
The starting acceleration can be improved.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an automatic transmission according to the present invention.

FIG. 2 is a diagram showing a relationship between an output port of a manual valve and a range of a shift lever.

FIG. 3 is a diagram showing a known connection relationship between a torque converter, a lockup clutch, and a gear unit of a transmission.

FIG. 4 is a flowchart of a program executed by a CPU used in the automatic transmission according to the present invention.

5 is a characteristic graph showing the relationship between the accelerator opening and the operation amount of the hydraulic control valve on the time axis in the program of FIG.

FIG. 6 is a block diagram schematically showing a conventional automatic transmission equipped with a lockup clutch.

[Explanation of symbols]

 1 Oil Pump 2 Pressure Valve 3 Solenoid Valve 4 Lockup Clutch 5 Manual Valve 6 Hydraulic Circuit 7 Speed Change Gear 9 Hydraulic Control Valve 10 CPU 11 Vehicle Speed Sensor 12 Throttle Sensor 13 Brake Switch In the drawings, the same reference numerals indicate the same or corresponding parts. ..

Claims (2)

[Claims] 1. A hydraulic pressure applied to a manual valve which is inserted between a vehicle speed detection means, an accelerator depression amount detection means, a brake operation detection means, a manual valve and a pressure valve for controlling the hydraulic pressure applied to the manual valve. And a control signal for controlling the vehicle speed, and when an output signal of each detecting means is input to detect the intention to stop the vehicle, the hydraulic control valve is controlled to cut off the hydraulic pressure to the manual valve. If the vehicle speed due to indicates that the vehicle is in a stopped state, the lockup clutch connected to the pressure valve is turned on to disable the torque converter, and the hydraulic pressure of the hydraulic control valve is controlled according to the subsequent accelerator depression amount to start the vehicle. An automatic transmission comprising: a control unit for controlling the automatic transmission. 2. The control means controls the hydraulic pressure to the manual valve to increase temporally for the same accelerator depression amount when controlling the hydraulic pressure to the manual valve according to the accelerator depression amount. Output hydraulic pressure of the hydraulic control valve
The automatic transmission according to claim 1, wherein the automatic transmission is controlled to 100%.