JP2010249230A - Fail-safe control method for vehicle automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fail-safe control method for an automatic transmission for a vehicle for restraining a transfer delay to a fail-safe state. <P>SOLUTION: Since a fail-safe valve 96 is operated under the output hydraulic pressure P<SB>b</SB>of a linear solenoid valve SLP in its dead zone with an area less than a predetermined duty ratio A% in control voltage S<SB>SLP</SB>of the linear solenoid valve SLP as the dead zone, when a solenoid control valve fails, the solenoid control valve can be maximally quickly transferred to the fail-safe state without making a determination. That is, the fail-safe control method for the automatic transmission for the vehicle can be provided for restraining the transfer delay to the fail-safe state. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a failsafe control method for an automatic transmission for a vehicle, and more particularly to an improvement for suppressing a delay in transition to a failsafe state.

  2. Description of the Related Art A fail-safe technique for an automatic transmission for a vehicle that performs predetermined fail-safe control when an electromagnetic control valve fails is known in a hydraulic control circuit that controls hydraulic pressure for performing shift control of an automatic transmission. For example, this is the control device for an automatic transmission described in Patent Document 1. According to this technique, the linear solenoid valve that is not energized among the linear solenoid valves that are operated by supplying an energization amount that exceeds a predetermined value is set to a predetermined value that prevents the linear solenoid valve from being operated by the abnormality determination unit. Since abnormality determination (failure determination) is performed by supplying an energization amount less than the value, the frequency of linear solenoid valve abnormality determination can be increased without affecting the shift control of the automatic transmission, and abnormality detection Accuracy can be improved.

JP 2007-205371 A

  However, in the conventional technology as described above, when the electromagnetic control valve fails, a failure determination based on the state of the result is performed, and then the determination is made to shift to the fail-safe state. For this reason, there is a possibility that adverse effects such as engine overrun due to a delay in transition may occur. For this reason, development of the fail safe control method of the automatic transmission for vehicles which suppresses the transition delay to a fail safe state was calculated | required.

  The present invention has been made against the background of the above circumstances, and an object thereof is to provide a fail-safe control method for an automatic transmission for a vehicle that suppresses a delay in transition to a fail-safe state. .

  In order to achieve such an object, the gist of the present invention is to operate a predetermined fail-safe valve at the time of failure of an electromagnetic control valve in a hydraulic control circuit that controls hydraulic pressure for performing shift control of an automatic transmission. A fail-safe control method for an automatic transmission for a vehicle, wherein a region where the control voltage of the electromagnetic control valve is within a predetermined range is defined as a dead zone, and the fail-safe valve is controlled by an output hydraulic pressure of the electromagnetic control valve in the dead zone. It is characterized by operating.

  According to this configuration, in the hydraulic control circuit for controlling the hydraulic pressure for performing the shift control of the automatic transmission, the fail-safe control method for the automatic transmission for a vehicle that operates the predetermined fail-safe valve when the electromagnetic control valve fails. The electromagnetic control valve has a dead zone where the control voltage of the electromagnetic control valve is within a predetermined range, and the fail safe valve is operated by the output hydraulic pressure of the electromagnetic control valve in the dead zone. When failing, it is possible to shift to the fail-safe state as quickly as possible without making a determination. That is, it is possible to provide a fail-safe control method for a vehicle automatic transmission that suppresses a delay in transition to a fail-safe state.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a skeleton diagram illustrating a configuration of a vehicle drive device to which the present invention is preferably applied. It is a block diagram explaining the input / output signal which concerns on the electronic controller provided in the vehicle in order to control the drive device etc. of FIG. It is a figure which shows an example of the shift map used for the shift control of the belt-type continuously variable transmission by the electronic controller of FIG. FIG. 3 is a diagram illustrating a main part of a configuration related to hydraulic control of an input side hydraulic cylinder and an output side hydraulic cylinder of a belt-type continuously variable transmission in the hydraulic control circuit of FIG. 2. It is a figure explaining the dead zone of the linear solenoid valve with which the hydraulic control circuit of FIG. 4 was equipped, and the threshold value which switches a fail safe valve.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a skeleton diagram illustrating a configuration of a vehicle drive device 10 to which the present invention is preferably applied. This drive device 10 is a horizontal automatic transmission that is suitably employed in an FF (front engine / front drive) type vehicle, and drives the power output from an engine 12 that is a power source for traveling to the left and right. This is a power transmission device for transmitting to the wheels 24L, 24R. That is, the output of the engine 12 includes a crankshaft of the engine 12, a torque converter 14 as a fluid transmission device, a forward / reverse switching device 16, a belt type continuously variable transmission (CVT) 18 that is an automatic transmission for a vehicle, It is configured to be distributed to the left and right drive wheels 24L, 24R via the reduction gear device 20 and the differential gear device 22.

  The engine 12 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine that generates driving force by combustion of fuel injected in a cylinder. The torque converter 14 is connected to the forward / reverse switching device 16 via a pump impeller 14p connected to the crankshaft of the engine 12 and a turbine shaft 34 corresponding to an output side member of the torque converter 14. A turbine impeller 14t is provided to transmit power through a fluid. A direct coupling clutch (lock-up clutch) 26 is provided between the pump impeller 14p and the turbine impeller 14t. The direct coupling clutch 26 is engaged or released by a hydraulic control circuit 90. When the direct coupling clutch 26 is completely engaged, the pump impeller 14p and the turbine impeller 14t are integrally rotated. It is configured as follows.

  The pump impeller 14p is connected to a mechanical hydraulic pump 28 that generates hydraulic pressure by rotating the pump impeller 14p, that is, by driving the engine 12. The hydraulic control circuit 90 performs shift control and belt clamping pressure control of the belt-type continuously variable transmission 18 with the hydraulic pressure output from the hydraulic pump 28, and controls the engagement and release of the direct coupling clutch 26. Or it is comprised so that the oil_pressure | hydraulic (original pressure) for supplying lubricating oil to each part may be generated.

  The forward / reverse switching device 16 is composed mainly of a forward clutch C1 and a reverse brake B1, and a double pinion planetary gear device 16p. With respect to the forward / reverse switching device 16, the turbine shaft 34 of the torque converter 14 is integrally connected to the sun gear 16s, and the input shaft 36 of the belt type continuously variable transmission 18 is integrally connected to the carrier 16c. ing. The carrier 16c and the sun gear 16s are selectively connected via a forward clutch C1, and the ring gear 16r is selectively fixed to a housing which is a non-rotating member via a reverse brake B1. It has become. The forward clutch C1 and the reverse brake B1 correspond to an intermittent device, and preferably both are hydraulic friction engagement devices that are frictionally engaged by a hydraulic cylinder.

  In the forward / reverse switching device 16 configured as described above, when the forward clutch C1 is engaged and the reverse brake B1 is released, the forward / reverse switching device 16 is brought into an integral rotation state. The turbine shaft 34 is directly connected to the input shaft 36, and a forward power transmission path is established (achieved), and the forward driving force is transmitted to the belt type continuously variable transmission 18 side. When the reverse brake B1 is engaged and the forward clutch C1 is released, the forward / reverse switching device 16 establishes (achieves) a reverse power transmission path, and the input shaft 36 is connected to the turbine. The shaft 34 is rotated in the opposite direction, and the driving force in the reverse direction is transmitted to the belt type continuously variable transmission 18 side. When both the forward clutch C1 and the reverse brake B1 are released, the forward / reverse switching device 16 is in a neutral state (power transmission cut-off state) in which power transmission is cut off.

  The belt-type continuously variable transmission 18 is a vehicular continuously variable transmission that is connected to the engine 12 via the torque converter 14 and the forward / reverse switching device 16 and that can continuously change the output of the engine 12. An input side variable pulley (primary sheave) 42 having a variable effective diameter provided on the input shaft 36, an output side variable pulley (secondary sheave) 46 having a variable effective diameter provided on the output shaft 44, and these variable A transmission belt 48 wound between pulleys 42 and 46 is provided.

The variable pulleys 42 and 46 are fixed rotating bodies 42a and 46a fixed to the input shaft 36 and the output shaft 44, respectively, and are not rotatable relative to the input shaft 36 and the output shaft 44 in the axial direction. Movable rotating bodies 42b and 46b provided so as to be movable, and an input-side hydraulic cylinder 42c and an output-side hydraulic cylinder 46c as hydraulic actuators that apply thrust to change the V-groove width therebetween, respectively. Has been. In such a variable pulley 42 and 46, by supplying hydraulic pressure P _PS to the input side hydraulic cylinder 42c is controlled by the hydraulic control circuit 90 which will be described later with reference to FIG. 4, V grooves of the variable pulleys 42 and 46 The width is changed to change the engagement diameter (effective diameter) of the transmission belt 48, and the gear ratio γ (= input shaft rotational speed N _IN / output shaft rotational speed N _OUT ) is continuously changed. Furthermore, the secondary pressure (hereinafter, referred to as the belt clamping pressure) is a hydraulic pressure of the output side hydraulic cylinder 46c by the P _SS is also pressure regulation control by the hydraulic control circuit 90 which will be described later with reference to FIG. 4, the drive belt 48 The belt clamping pressure is controlled so that no slippage occurs.

  FIG. 2 is a block diagram for explaining input / output signals related to the electronic control unit 50 provided in the vehicle for controlling the vehicle drive device 10 and the like. The electronic control unit 50 is configured to include a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like, for example. The CPU uses a temporary storage function of the RAM and stores a program stored in the ROM in advance. In accordance with the signal processing, the output control of the engine 12, the shift control of the belt-type continuously variable transmission 18, the belt clamping pressure control, the torque capacity control of the direct coupling clutch 26, and the like are executed. If necessary, the engine 12 and the belt type continuously variable transmission 18 to the direct clutch 26 are controlled separately.

As shown in FIG. 2, the electronic control device 50 receives signals from various sensors that are provided in each part of the vehicle and indicate the state of the vehicle. That is, the detected crankshaft angle of rotation by an engine rotational speed sensor 52 (position) A _CR (°) and the rotational speed signal representing the crankshaft rotation speed corresponding to the (engine rotational speed) N _E of the engine 12, the turbine rotation The signal representing the rotational speed (turbine rotational speed) _NT of the turbine shaft 34 detected by the speed sensor 54, and the input rotational speed of the belt type continuously variable transmission 18 detected by the input shaft rotational speed sensor 56. The output shaft 44 is a signal representing the rotational speed (input shaft rotational speed) N _IN of the input shaft 36 and the output rotational speed of the belt type continuously variable transmission 18 detected by a vehicle speed sensor (output shaft rotational speed sensor) 58. speed of rotation (the output shaft rotational speed) N _OUT ie vehicle speed signal representing a vehicle speed V corresponding to the output shaft speed N _OUT, detected by a throttle sensor 60 Intake pipe 32 of the engine 12 throttle valve opening signal representing the throttle valve opening theta _TH of the electronic throttle valve 30 provided in (see Figure 1) was detected in the engine 12 by a cooling water temperature sensor 62 signal representing the cooling water temperature T _W, a signal representative of the oil temperature T _CVT of the hydraulic circuit 90, such as the belt type continuously variable transmission 18 detected by the CVT oil temperature sensor 64, an accelerator pedal detected by the accelerator opening sensor 66 an accelerator opening signal representative of the accelerator opening a _CC is an operation amount of 68, a brake operation signal indicating whether B _ON operation of the foot brake is a service brake, which is detected by a foot brake switch 70, detected by the lever position sensor 72 and a lever position of the shift lever 74 (operating position) so that the operation position signal or the like representing the P _SH is supplied Yes.

The electronic control unit 50 outputs a signal for controlling the operation of each part of the vehicle. That is, the engine output control command signal S _E for controlling the output of the engine 12 is injected from, for example, a throttle signal for driving a throttle actuator 76 for controlling the opening / closing of the electronic throttle valve 30 or a fuel injection device 78. An injection signal for controlling the amount of fuel, an ignition timing signal for controlling the ignition timing of the engine 12 by the ignition device 80, and the like are output. Further, the shift control command signal S _T for example, a linear solenoid valve SLP for controlling the flow rate of the hydraulic fluid to the input side hydraulic cylinder 42c (FIG. 4 for changing the speed ratio γ of the belt-type continuously variable transmission 18 command signal for driving the reference), the transmission clamping force control command for aligning the clamping force of the belt 48 signal S _B for example, a belt clamping pressure P _out pressure the regulating linear solenoid valve SLS or the like (see FIG. 4) A command signal for driving, a lock-up control command signal for controlling engagement or disengagement of the direct clutch 26, for example, an operation of a lock-up control valve for switching between an engaged state and a disengaged state of the direct clutch 26. It is described later command signal for driving a solenoid valve for controlling the command signal and the like for driving the linear solenoid valve for controlling the line pressure P _L is And it is outputted to the hydraulic control circuit 90.

  The shift lever 74 is disposed, for example, in the vicinity of the driver's seat, and is one of five lever positions “P”, “R”, “N”, “D”, and “L” that are sequentially positioned. It is designed to be manually operated. The “P” position (range) releases the power transmission path of the driving device 10, that is, a neutral state (neutral state) in which the power transmission of the driving device 10 is interrupted, and mechanically outputs the output by the mechanical parking mechanism. This is a parking position (position) for preventing (locking) the rotation of the shaft 44. The “R” position is a reverse travel position (position) for making the rotation direction of the output shaft 44 reverse. Further, the “N” position is a neutral position (position) for achieving a neutral state in which the power transmission of the driving device 10 is interrupted. Further, the “D” position is a forward travel position (position) in which an automatic transmission mode is established and an automatic transmission control is executed within a transmission range that allows the belt-type continuously variable transmission 18 to be changed. The “L” position is an engine brake position (position) where a strong engine brake is applied. Thus, the “P” position and the “N” position are non-traveling positions that are selected when the vehicle is not traveling, and the “R” position, the “D” position, and the “L” position are when the vehicle is traveling. This is the selected driving position.

Further, the electronic control unit 50 executes shift control for automatically and continuously changing the speed ratio γ of the belt type continuously variable transmission 18 according to the driving state of the vehicle. For example, basically, an accelerator operation amount θ _ACC (accelerator opening A _CC) detected by the accelerator opening sensor 66 from an automatic shift map as shown in FIG. 3 which is predetermined and stored in a predetermined storage device. ) And the vehicle speed V detected by the vehicle speed sensor 58, the target rotational speed NINT on the input side is calculated, and the actual input shaft rotational speed NIN corresponds to the deviation so that the actual rotational speed NIN matches the target rotational speed NINT. Then, the shift control of the belt type continuously variable transmission 18 is performed. The map in FIG. 3 corresponds to the shift control relationship during normal driving, and the target rotational speed NINT that sets a larger gear ratio γ is set as the vehicle speed V is lower and the accelerator operation amount θ _ACC is larger. ing. The vehicle speed V corresponds to the output shaft rotational speed NOUT, the target rotational speed NINT, which is the target value of the input shaft rotational speed NIN, corresponds to the target speed ratio, and the minimum speed ratio γ of the belt type continuously variable transmission 18 It is determined within a range between _min and the maximum gear ratio γ _max .

FIG. 4 is a diagram for explaining a main part of the configuration relating to the hydraulic control of the input side hydraulic cylinder 42c and the output side hydraulic cylinder 46c of the belt type continuously variable transmission 18 in the hydraulic control circuit 90. As shown in FIG. 4, the hydraulic pressure control circuit 90 uses the hydraulic pressure LPM2 regulated by a predetermined pressure regulating valve (not shown) as a source pressure in accordance with the control voltage S _SLP supplied from the electronic control unit 50. A linear solenoid valve SLP, which is an electromagnetic control valve that outputs a hydraulic pressure P _SLP related to the control of the input side hydraulic cylinder 42c, and a control pressure S _SLP supplied from the electronic control unit 50 using the hydraulic pressure LPM2 as a source pressure. A linear solenoid valve SLS, which is an electromagnetic control valve that outputs a hydraulic pressure P _SLS related to the control of the output side hydraulic cylinder 46c, and the hydraulic pressure P _SLP output from the linear solenoid valve SLP is supplied to the input side hydraulic cylinder 42c. a transmission ratio control valve 92 to output the hydraulic pressure P _PS is, the output-side oil according to the hydraulic pressure P _SLS output from the linear solenoid valve SLS A clamping pressure control valve 94 to output the hydraulic pressure P _SS supplied to the cylinder 46c, is operated upon failure of the linear solenoid valve SLP (the failure) so that the fail state (valve element position of the left side in FIG. 4) And a fail-safe valve 96 to be provided.

Said fail-safe valve 96, when failure of the linear solenoid valve SLP (the failure) to stop supply to the input side hydraulic cylinder 42c of the hydraulic P _PS outputted from the transmission ratio control valve 92 (input) . That is, in the state where the linear solenoid valve SLP is operating normally, the hydraulic P _PS of the valve element 96a is output from the transmission ratio control valve 92 is a valve element position of the right side shown in FIG. 4 While the supply to the input side hydraulic cylinder 42c is performed, when the linear solenoid valve SLP fails, the valve element 96a is set to the left valve element position shown in FIG. hydraulic pressure P supplied _PS said to the input side hydraulic cylinder 42c of the is configured to be blocked (blocking) that. In order to realize such an operation, a spring 96b that urges the valve element 96a to the left valve element position is provided, and the hydraulic pressure P _SLP supplied from the linear solenoid valve _SLP is a predetermined threshold value P. while the valve element 96a is a valve element position of the right side of FIG. 4 in the case where _b above, when the hydraulic pressure P _SLP is less than the threshold value P _b is left the valve element 96a is shown in FIG. 4 Each pressure receiving area in the valve element 96a and the biasing force of the spring 96b are determined so that the position of the valve element is the same.

In configured hydraulic control circuit 90, the hydraulic control of the output hydraulic pressure P _PS by the input-side hydraulic cylinder 42c of the transmission ratio control valve 92 which is determined in accordance with the oil pressure P _SLP of the linear solenoid valve SLP is performed as previously described . That is, by supplying hydraulic pressure P _PS to the input side hydraulic cylinder 42c is controlled by the speed ratio control valve 92, takes the drive belt 48 and the V-groove width is changed in the variable pulley 42 and 46 diameter (Effective diameter) is changed, and the gear ratio γ of the belt type continuously variable transmission 18 is continuously changed. Further, said output side hydraulic pressure control of hydraulic cylinder 46c by the output oil pressure P _SS of the clamping pressure control valve 94 which is determined depending on the hydraulic pressure P _SLS linear solenoid valve SLS is performed. That is, when the secondary pressure P _SS is the clamping pressure control valve pressure regulation control by 94 is a hydraulic pressure of the output side hydraulic cylinder 46c, the belt clamping force is controlled so as not to cause slipping on the drive belt 48 .

Here, in the hydraulic control circuit 90 of the present embodiment, regarding the hydraulic control of the input side hydraulic cylinder 42c by the transmission ratio control valve 92, the control voltage (duty ratio) S _{SLP of the} linear solenoid valve SLP related to the control is controlled. Is a dead zone in which the value is equal to or less than a predetermined value (predetermined A%). FIG. 5 is a diagram for explaining the dead zone of such a linear solenoid valve SLP, in which general characteristics in the prior art are indicated by broken lines, and characteristics in the present embodiment are indicated by solid lines. As shown in FIG. 5, in the hydraulic control circuit 90 according to the present embodiment, the input side hydraulic cylinder 42c is controlled in a region where the control voltage (duty ratio) S _{SLP of the} linear solenoid valve _SLP is not less than A% and not more than 100%. output hydraulic pressure P _PS control oil pressure (primary sheave pressure) i.e. the transmission ratio control valve 92 is configured to be controlled. In other words, in the region where the control voltage (duty ratio) S _{SLP of the} linear solenoid valve SLP is less than A%, the change of the control voltage S _SLP or the change of the hydraulic pressure P _SLP is the output of the speed ratio control valve 92. It is not reflected in the hydraulic pressure _PPS .

The fail safe valve 96 is configured to be actuated by an output hydraulic pressure in a dead zone of the linear solenoid valve SLP. That is, as shown in FIG. 5, the linear solenoid valve pressure P _SLP is right valve the valve element 96a is shown in FIG. 4 when a predetermined threshold P _b or contained in the dead band supplied from SLP while being a child position normal state is established, left the valve element 96a in the case hydraulic pressure P _SLP is less than the threshold value P _b (if it is within the range shown by hatching in FIG. 5) is shown in FIG. 4 The pressure receiving area of the valve element 96a and the urging force of the spring 96b are determined so that a fail state is established. In other words, in the hydraulic control circuit 90 of this embodiment, the output of the linear solenoid valve SLP pressure P _PS actual use area (100% or less duty ratio A%) and the dead zone (the duty ratio of 0% to A% They are separated in less than), and is configured the fail-safe valve 96 at the predetermined threshold value P _b included in the dead zone to switch the fail-side.

Thus, according to this embodiment, in the hydraulic control circuit 90 that controls the hydraulic pressure for performing the shift control of the belt type continuously variable transmission 18, the predetermined fail-safe valve 96 is used when the linear solenoid valve SLP fails. A fail-safe control method for a vehicular automatic transmission that activates a dead zone in which the control voltage S _SLP of the linear solenoid valve _SLP is within a predetermined range, that is, a duty ratio of 0% or more and less than A%. since the by the output oil pressure P _b of the linear solenoid valve SLP is intended for actuating the fail safe valve 96, if the electromagnetic control valve is fail, be transferred to as soon as possible the fail-safe state without performing the determination Can do. That is, it is possible to provide a fail-safe control method for a vehicle automatic transmission that suppresses a delay in transition to a fail-safe state.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and may be implemented in other modes.

For example, in the above-described embodiment, the example in which the present invention is applied to the hydraulic control circuit 90 including the linear solenoid valve SLP in which the region where the control voltage S _SLP is less than the predetermined duty ratio A% is a dead zone has been described. However, for example, the present invention is preferably applied to a configuration in which a dead zone is defined in a region on the side where the control voltage is relatively high. That is, the present invention is also suitably applied to a hydraulic control circuit including a linear solenoid valve in which a region where the control voltage is equal to or higher than a predetermined duty ratio is a dead zone.

  In the above-described embodiment, the hydraulic control circuit 90 including the fail-safe valve 96 whose valve position is switched according to the hydraulic pressure from the single linear solenoid valve SLP has been described, but two or more electromagnetic controls are provided. The present invention is also suitably applied to a hydraulic control circuit including a fail-safe valve that is switched according to an AND condition or an OR condition related to the output hydraulic pressure of the valve.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

18: Belt type continuously variable transmission (automatic transmission for vehicles)
90: Hydraulic control circuit 96: Fail-safe valve SLP, SLS: Linear solenoid valve (electromagnetic control valve)

Claims (1)

In a hydraulic control circuit for controlling a hydraulic pressure for performing a shift control of an automatic transmission, a fail-safe control method for an automatic transmission for a vehicle that operates a predetermined fail-safe valve at the time of a failure of an electromagnetic control valve,
A fail-safe of an automatic transmission for a vehicle, characterized in that a region where the control voltage of the electromagnetic control valve is within a predetermined range is a dead zone, and the fail-safe valve is operated by an output hydraulic pressure of the electromagnetic control valve in the dead zone. Control method.

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