JPH05141284A - Control device for on-vehicle automatic transmission - Google Patents

Abstract

PURPOSE:To prevent the deterioration in operability by measuring the elapsed time after it has been detected that a shift lever has been operated from a traveling range to a nontraveling range, and by forbidding the fuel cut in the nontraveling range, when the elapsed time exceeds a prescribed value. CONSTITUTION:In an automatic transmission, when a shift lever is operated from a traveling range to a nontraveling range, the hydraulic friction-engaging device that has been engaged hitherto is released for cutting off a power- transmission route. In the case where the shift lever is in the nontraveling range, when the rotating speed of an engine detected by a rotating-speed detecting means exceeds a prescribed set value, fuel cut is carried out by a fuel-cutting means for restraining the rise in the engine rotating speed. In this case, the elapsed time after a shift-operation detecting means has detected that the shift lever has been operated to the nontraveling range is measured by a time-measuring means, and when the measured elapsed time exceeds a prescribed value, the above fuel cut is forbidden by a fuel-cut forbidding means.

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 an automatic transmission for a vehicle, and more particularly to a technique for solving the inconvenience caused by the engine rotation speed increase suppression control when a shift lever is operated to a non-travel range. is there.

[0002]

2. Description of the Related Art When a shift lever is operated from a running range to a non-running range, a hydraulic friction engagement device that has been engaged until then is released and a power transmission path is cut off. Transmissions are known. In such an automatic transmission, immediately after the shift lever is operated from the running range such as the D range and the R range to the non-running range such as the P range and the N range, the hydraulic response is delayed due to the hydraulic response delay. The friction engagement device is released after a lapse of a predetermined time. However, if the accelerator pedal is depressed during that time, the hydraulic friction engagement device is not completely released by the centrifugal hydraulic pressure and dragging occurs. For this reason,
When the shift lever is operated to the non-traveling range such as the P range or the N range, the drag engagement of the friction engagement device, which tends to occur when the shift lever is operated to the non-traveling range, is suppressed to improve durability. In order to improve the engine speed, it has been proposed to provide means for executing a fuel cut when the engine speed exceeds a predetermined set value to suppress an increase in the engine speed. For example, it is a control device for an automatic transmission mounted on a Saturn vehicle of General Motors (GM).

[0003]

By the way, according to the above-described conventional automatic transmission control system for a vehicle, the engine speed can be increased above a predetermined value in a non-driving range such as the P range or the N range. Since it is not possible, there is a drawback that it is impossible to check the engine operation and charge the battery. In addition, since the racing operation for increasing the engine rotation speed cannot be performed in the above-mentioned non-driving range, there is an inconvenience that a driver or the like is misunderstood that the engine has failed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydraulic friction engagement device associated with the shift lever being operated from a running range to a non-running range. It is an object of the present invention to provide a control device for an automatic transmission for a vehicle, in which drag is suppressed and the engine speed can be increased even when the shift lever is operated in the non-traveling range.

[0005]

The gist of the present invention for attaining the above object is that the shift lever is operated from the traveling range to the non-traveling range as shown in the schematic diagram of FIG. In an automatic transmission for a vehicle in which a hydraulic friction engagement device that has been engaged until then is released and a power transmission path is cut off, engine rotation speed detection means for detecting a rotation speed of an engine, and When the shift lever is operated to the non-driving range, when the engine speed exceeds a predetermined set value, the fuel cut means for executing the fuel cut in the non-running range to suppress the increase in the engine speed is provided. A control device comprising: (a) shift operation detecting means for detecting that the shift lever has been operated from a travel range to a non-travel range; and (b) the shift operation. A time measuring means for measuring an elapsed time after it is detected that the shift lever is operated from the traveling range to the non-traveling range by the detecting means, and (c) the elapsed time measured by the time measuring means is predetermined. When the value exceeds the value, the fuel cut prohibiting means for prohibiting the fuel cut of the non-running range by the fuel cut means is included.

[0006]

With this configuration, the time elapsed from the time when the shift operation detecting means detects that the shift lever is operated from the traveling range to the non-traveling range is measured by the time measuring means, and the elapsed time is predetermined. If the value exceeds the specified value, the fuel cut in the non-running range is prohibited by the fuel cut prohibiting means.

[0007]

According to the present invention, therefore, the shift lever is operated from the running range to the non-running range by the fuel cut means for performing the fuel cut in the non-running range when the engine speed exceeds a predetermined set value. Not only the drag of the hydraulic friction engagement device related to is suppressed but also when the elapsed time exceeds a predetermined value,
Since the fuel cut of the non-driving range is prohibited and the engine speed can be increased above the predetermined set value in the non-driving range such as the P range and the N range, it is possible to check the engine operation and charge the battery. Become. In addition, since the racing operation for increasing the engine rotation speed can be performed in the non-driving range, it is possible to eliminate the misunderstanding to the driver that the engine has failed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 2 is a skeleton view of a vehicle power transmission device to which an embodiment of the present invention is applied. In the figure, the power of the engine 10 is transmitted to the drive wheels via a torque converter 12 with a lockup clutch 12, a stepped automatic transmission 14 including three sets of planetary gear units, and a differential gear device (not shown). It has become so.

The torque converter 12 is the engine 1
Pump impeller 18 connected to zero crankshaft 16
And a turbine impeller 22 fixed to the input shaft 20 of the automatic transmission 14 and rotated by receiving oil from the pump impeller 18, and a housing 26 which is a non-rotating member via a one-way clutch 24. Stator wheel 28
And a lock-up clutch 32 connected to the input shaft 20 via a damper 30. When the hydraulic pressure in the disengagement side oil chamber 33 is higher than that in the engagement side oil chamber 35 in the torque converter 12, the lockup clutch 32 is disengaged, so that the input / output rotational speed ratio of the torque converter 12 is reduced. The torque is transmitted at a corresponding amplification factor. However, when the oil pressure in the engagement-side oil chamber 35 is higher than that in the disengagement-side oil chamber 33, the lock-up clutch 32 is engaged, so that the input / output members of the torque converter 12, that is, the crankshaft 16 and the input. The shaft 20 is directly connected.

The automatic transmission 14 has three coaxially arranged parts.
Set of single pinion type planetary gear units 34, 36, 38
And an input shaft 20, an output gear 39 that rotates together with a ring gear of the planetary gear device 38, and a counter shaft (output shaft) 40 that transmits power between the differential gear device. Some of the components of the planetary gear units 34, 36 and 38 are not only integrally connected to each other, but also selectively connected to each other by three clutches C ₀ , C ₁ and C ₂ . Further, the planetary gear units 34, 36, 3
Some of the eight components are four brakes B ₀ , B ₁ , B
₂ and B ₃ are selectively connected to the housing 26, and further, some of the components are engaged with each other or with the housing 26 by their rotational directions by three one-way clutches F ₀ , F ₁ and F ₂ . It is supposed to be done.

FIG. 4 is a sectional view showing a part of the automatic transmission 14 in more detail. The clutches C ₀ , C ₁ ,
C _2, brake _{B 0, B 1, B 2} , B 3 , as shown in FIG. 4, are composed of multiple-disc clutches and band type brake or the like, each adapted to be actuated by a hydraulic actuator By controlling the operation of these hydraulic actuators by the electronic control unit 42, which will be described later, as shown in FIG.
It is possible to obtain four forward gears and one reverse gear with different values (= rotational speed of input shaft 20 / rotational speed of counter shaft 40). In Fig. 3, "1st", "2nd", "3r"
“D” and “O / D (overdrive)” represent the first speed gear stage, the second speed gear stage, the third speed gear stage, and the fourth speed gear stage on the forward side, respectively. Becomes progressively smaller from the first gear stage to the fourth gear stage. Since the torque converter 12 and the automatic transmission 14 are configured symmetrically with respect to the axis, the lower side of the rotation axis of the input shaft 20 and the upper side of the rotation axis of the counter shaft 40 are shown in FIG. It is omitted.

Each of the clutches C ₀ , C ₁ and C ₂ is constructed so as to rotate together with the rotary shaft. The configuration of the clutches C ₁ and C ₂ will be described in detail below with reference to FIG. An intermediate shaft 42 and a sleeve shaft 44 concentric with the intermediate shaft 42 are provided following the input shaft 20, a first clutch drum 46 is fixedly mounted on the input shaft 20, and a second clutch drum 48 is provided on the sleeve shaft 44. Is fixed.
The planetary gear 50p of the planetary gear device 34 is rotatably supported by a carrier 50c integrally provided on the intermediate shaft 42, and is rotatably provided separately from the sun gear 50s provided at the shaft end of the sleeve shaft 44. Ring gear 50r
Has been meshed with. The brake B ₁ is of a band type, and is brought into sliding contact with the outer peripheral surface of the second clutch drum 48 by a hydraulic actuator (not shown).

The clutch C ₁ and its hydraulic actuator are housed in the first clutch drum 46. First
An annular first piston 54 is slidably fitted in the clutch drum 46, and a friction plate 56 rotating together with the first clutch drum 46 and a friction plate 58 rotating together with the ring gear 50r are stacked. It is adapted to be pressed by the first piston 54. Hydraulic oil is supplied from a hydraulic control circuit 70 to a first oil chamber 60 surrounded by the first piston 54 and the first clutch drum 46. Similarly, the clutch C ₂ and its hydraulic actuator are also connected to the second clutch drum 48.
A friction plate 62 that is housed inside and that rotates together with the second clutch drum 48 and a friction plate 64 that rotates together with the first clutch drum 46 are pressed by the second piston 66. It should be noted that the first piston 54 has a second spring
The pistons 66 are respectively returned by return springs 67.

The hydraulic control circuit 70 includes the automatic transmission 1 described above.
A shift control hydraulic control circuit for controlling the fourth gear and a engagement control hydraulic control circuit for controlling the engagement of the lockup clutch 32 are provided. As is well known, the hydraulic control circuit for shifting control is a solenoid.
The first solenoid valve 7 is provided with a first solenoid valve 72 and a second solenoid valve 74 that are turned on and off by No. 1 and solenoid No. 2, respectively, and is controlled by an electronic control unit 76.
By operating the second and second solenoid valves 74, the clutch and the brake are selectively operated as shown in FIG. 3 to establish any one of the first to fourth speed gear stages. It is designed to be used. Further, the engagement control hydraulic control circuit includes a third solenoid valve 78 for switching the engagement state of the lockup clutch 32 and a fourth solenoid valve 80 for controlling the slip state of the lockup clutch 32. The hydraulic control circuit 70 includes
A manual valve operated by a shift lever 96 described later is provided, and when the shift lever 96 is operated from a non-running range such as P or N range to a running range such as D, S, L, R, Supply of hydraulic oil to the friction engagement device that establishes the forward or reverse gear is allowed.

The electronic control unit 76 includes a CPU 82 and a ROM.
A so-called microcomputer including 84, RAM 86, an interface (not shown), and the like.
A throttle sensor 88 for detecting a throttle valve opening provided in an intake pipe of the engine 10, an engine rotation speed sensor 90 for detecting a rotation speed of the engine 10, an input shaft for detecting a rotation speed of an input shaft 20 of the automatic transmission 14. The rotation sensor 92, the output shaft rotation sensor 94 that detects the rotation speed of the output shaft 34 of the automatic transmission 14, and the operating position of the shift lever 96, that is, any of the L, S, D, N, R, and P ranges are detected. From the operation position sensor 98, a signal representing the throttle valve opening θ _th , a signal representing the engine rotation speed N _e (pump impeller rotation speed N _P ), and an input shaft rotation speed N _in
A signal indicating the (turbine wheel wheel rotation speed N _T ), a signal indicating the output shaft rotation speed N _out, and a signal indicating the operation position P _s of the shift operation lever 96 are respectively supplied. The CPU 82 of the electronic control unit 42 has a RAM 86.
The input signal is processed according to a program stored in advance in the ROM 84 while using the temporary storage function of the automatic transmission 1
4 for executing the shift control of No. 4 and the engagement control of the lockup clutch 32, a first solenoid valve 72, a second solenoid valve 74,
The third solenoid valve 78 and the fourth solenoid valve 80 are controlled respectively. In the above shift control, a shift diagram corresponding to an actual shift gear is selected from a plurality of shift diagrams stored in the ROM 84 in advance, and the running state of the vehicle, for example, the throttle valve opening θ _th is selected from the shift diagram. The shift gear is determined on the basis of the vehicle speed SPD calculated from the output shaft rotation speed N _out, and the first solenoid valve 7 is provided so as to obtain the shift gear.
2. The second solenoid valve 74 is driven.

The vehicle of this embodiment has an engine control unit 10
0 is provided. The engine control device 100 is supplied with a signal representing the intake air amount Q from an intake air amount sensor 102 provided in the intake pipe, and a throttle valve opening θ _th from a throttle sensor 88 provided in the intake pipe. Is supplied. Further, from the oxygen sensor 104 provided in the exhaust pipe (not shown), a signal S _O2 representing the concentration of oxygen contained in the exhaust gas is sent to the air-fuel ratio control device 10
It is supplied to 0.

The engine control unit 100, like the electronic control unit 76, has a CPU 106, a ROM 108, and a RAM.
A microcomputer including a CPU 1
06, pre-ROM108 while determining the basic injection time T _p based on the actual engine speed N _e and the intake air quantity Q from the stored relationship, the basic injection time T _p the correction in accordance with signals from the sensors Add. For example, when the amount of oxygen in the exhaust gas is on the lean side, the fuel injection amount is increased, but when it is on the rich side, the fuel injection amount is decreased and the air-fuel ratio is made the ideal air-fuel ratio. A correction signal is generated, and the basic injection time T _p is corrected based on the air-fuel ratio feedback correction signal,
The fuel is injected from the fuel injection valve 112 into the intake pipe 80 for the corrected injection time T _F. Further, the engine control device 100 prevents the catalyst from being heated and saves fuel when the actual engine rotation speed N _e is preset and exceeds the fuel cut rotation speed during decelerating travel when the throttle valve opening is at the idle position. The fuel supply from the fuel injection valve 112 is cut off by executing a so-called fuel cut for. Further, the engine control device 100 shuts off the fuel supply from the fuel injection valve 112 even when the fuel cut signal F _cut is supplied from the electronic control device 76.

The main part of the operation by the electronic control unit 42, that is, the fuel cut control in the non-traveling range of the shift lever 96 will be described in detail below with reference to the flowchart of FIG.

In the figure, in step S1, it is determined whether or not the shift lever 96 has been operated to the non-traveling range such as the P range or the N range. If the determination in step S1 is negative, the content of the timer counter C is cleared to "0" in step S2, and then this routine is ended. The timer counter C is for counting the elapsed time after the shift lever 96 is operated to the non-running range such as the P range or the N range. But,
If the determination in step S1 is affirmative, "1" is added to the content of the timer counter C in step S3. In the following step S4, it is determined whether or not the fuel cut control in the non-running range is being performed based on whether or not the content of the fuel cut flag F is "1".

When the fuel cut control for the non-running range is not executed, the determination at step S4 is negative, and therefore, at step S5, it is determined whether or not the content of the timer counter C has reached a preset determination reference value T. Or
In other words, it is determined whether or not a certain determination reference time T has elapsed since the shift lever 96 was operated to the P range or the N range. The judgment reference time T is set in advance so that the friction plate of the clutch C ₁ is not dragged due to the return of the first piston 54 and the second piston 66 after the shift lever 96 is switched to the non-traveling range, and the fuel cut control is unnecessary in advance. It is an experimentally determined time, for example
A value of about 0.8sec is set. FIG. 6 shows the shift lever 9
6 shows changes in the output shaft torque of the automatic transmission 14 and the hydraulic pressure of the oil pressure in the first oil chamber 60 of the clutch C ₁ from the time of operating to the non-running range of No. 6, and these changes in the judgment reference time T are as follows. The period is set to end sufficiently.

If the determination in step S5 is affirmative, the fuel cut control for the non-running range is not necessary, so this routine is ended. However, if the determination in step S5 is negative, the subsequent step S5
At 6, it is determined whether the engine rotation speed N _e has become equal to or higher than a preset determination reference value N ₁ . The determination reference value N ₁ is determined by the clutch C ₁ due to a delay in response when the shift lever 96 is operated from the traveling range to the non-traveling range.
During the residual engagement period, the centrifugal oil pressure in the first oil chamber 60 or the second oil chamber 68 generated by the transmission of the rotation from the engine 10 further causes the drag of the clutch C ₁ to be a problem in the minimum rotational speed range. Value, for example 4
A value of about 000 rpm is used. FIG. 7 shows the relationship between the centrifugal oil pressure generated in the first oil chamber 60 of the clutch C ₁ and its rotation speed, and the above-mentioned judgment reference value N ₁ is illustrated on the rotation speed axis. In FIG. 7, the area on the right side of the judgment reference value N ₁ is an area where the durability of the clutch C ₁ becomes a problem.

If the engine speed N _e is less than the judgment reference value N ₁ , the fuel cut control in the non-running range is not necessary, so the judgment in step S6 is denied and this routine is ended. However, when the engine speed N _e becomes equal to or higher than the determination reference value N ₁ , the determination in step S6 is affirmative, so the content of the fuel cut flag F is set to "1" and the fuel cut is executed in step S7. Then, the fuel cut signal F _cut is sent from the electronic control unit 76 to the engine control unit 10.
Since it is supplied to 0, the fuel supply from the fuel injection valve 112 is cut off.

Since the content of the fuel cut flag F is set to "1" at the same time when the fuel cut control of the non-running range is executed as described above, the determination at step S4 in the next control cycle is affirmed. So
In step S8, it is determined whether the engine rotation speed N _e has become equal to or lower than a preset determination reference value N ₂ . The judgment reference value N ₂ is a value for providing a hysteresis for stabilizing the start judgment of the fuel cut control in the non-running range, and is set to a value slightly lower than the judgment reference value N ₁ . If the determination in step S8 is negative, this routine is ended to maintain the fuel cut control even in the non-running range. However, if the determination in step S8 is positive, the output of the fuel cut signal F _cut from the electronic control unit 76 is stopped and the fuel cut by the engine control unit 100 is stopped in step S9.

As described above, according to this embodiment, when the engine speed N _e exceeds the predetermined set value N ₁ , the engine controller 100 causes the fuel cut to be executed in step S7 corresponding to the fuel cut means. hand,
Since the drag of the clutch C _{1 and the} like associated with the shift lever 96 being operated from the traveling range to the non-traveling range is suppressed, burning and sticking of the clutch C _{1 and the} like are eliminated, and the clutch C _{1 and the} like are removed. Movement of the vehicle in the non-driving range due to burning or sticking is suitably prevented.

Further, according to the present embodiment, the elapsed time C from when it is detected that the shift lever 96 is operated from the traveling range to the non-traveling range in step S1 corresponding to the shift operation detecting means is the time measuring means. Step S corresponding to
When it is determined that the elapsed time C is equal to or greater than the predetermined value T in step S5 corresponding to the fuel cut prohibiting means, the output of the fuel cut signal F _cut is stopped and the engine control device 100 is stopped.
Fuel cut by is prohibited.

Therefore, when the elapsed time C after the shift lever 96 is operated from the running range to the non-running range exceeds a predetermined value, the engine speed is changed in the non-running range such as the P range or the N range. Since the speed N _e can be raised above the predetermined set value N _1, it is possible to check the engine operation and charge the battery. In addition, since the racing operation for increasing the engine rotation speed N _e can be performed in the non-driving range of the shift lever 96, it is possible to eliminate the misunderstanding to the driver that the engine has failed.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other modes.

For example, in step S5 of the above-mentioned embodiment, the constant judgment reference time T is used, but it may be a function value that increases as the hydraulic oil temperature decreases.
Further, it may be a clearance between the first piston 54 of the clutch C ₁ and the friction plate, that is, a function value that increases with the moving stroke of the first piston 54.

Further, the judgment reference values N ₁ and N ₂ in steps S6 and S8 of the above-described embodiment may be function values that increase as the hydraulic oil temperature decreases, or the first piston 54 and the second piston. It may be a function value that increases with the movement stroke of 66.

Further, in the above-mentioned embodiment, the shift lever 96
Although but it is operated from the running range to the non-driving range it has been determined based on a signal from the operating position sensor 98, instead of this, the hydraulic pressure of the clutch C ₁ by a pressure sensor for detecting the hydraulic pressure of clutch C ₁ It is also possible to make a determination based on the detection of a decrease in

The above description is merely one embodiment of the present invention, and the present invention can be variously modified without departing from the gist thereof.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the gist of the present invention.

FIG. 2 is a diagram showing a vehicle power transmission device to which a control device according to an embodiment of the present invention is applied.

FIG. 3 is a table for explaining a relationship between a combination of operations of a first solenoid valve and a second solenoid valve and a shift speed obtained by the combination in the automatic transmission of FIG.

FIG. 4 is a diagram illustrating a configuration of a main part of the automatic transmission of FIG.

FIG. 5 is a flowchart illustrating an operation of the electronic control device of FIG.

FIG. 6 is a time chart explaining the operation of the electronic control device of FIG.

7 is a diagram showing the relationship between the input shaft rotation speed and the centrifugal hydraulic pressure generated by the rotation in the automatic transmission of FIG.

[Explanation of symbols]

14 automatic transmission 90 an engine speed sensor (engine rotational speed detecting means) 96 shift lever clutch C _1, C ₂ friction engagement device step S1 shifting operation detection means step S3 clock means step S5 fuel cut prohibiting means step S7 fuel cut means

Claims (1)

[Claims] 1. When the shift lever is operated from the traveling range to the non-traveling range, the hydraulic friction engagement device that has been engaged until then is released and the power transmission path is cut off. In the transmission, engine rotation speed detecting means for detecting the rotation speed of the engine, and when the shift lever is operated to the non-traveling range, when the engine rotation speed exceeds a predetermined set value, the fuel cut of the non-traveling range is performed. And a fuel-cutting means for suppressing an increase in the rotation speed of the engine, wherein the shift-operation detecting means detects that the shift lever is operated from a running range to a non-running range. , The elapsed time after the shift operation detecting means detects that the shift lever is operated from the traveling range to the non-traveling range And a fuel cut prohibiting means for prohibiting the fuel cut of the non-running range by the fuel cut means when the elapsed time measured by the time measure exceeds a predetermined value. Control device for automatic transmission for vehicles