JP4146118B2 - Control method of clutch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a clutch control method, and more particularly to a method for controlling connection / disconnection of a wet friction clutch provided in a power transmission system of a vehicle.
[0002]
[Prior art]
The present inventors provide a fluid coupling (including a torque converter) that can be locked up in series with a wet friction clutch between an engine and a transmission, and a vehicle that automatically connects and disconnects the wet friction clutch during a shift. A power transmission device was newly developed. In this case, if a gear-in operation is performed while the vehicle is stopped, the clutch is automatically connected thereafter, and creep occurs. This is the same as a normal AT car.
[0003]
If the clutch is connected too early, a clutch engagement shock (so-called garage shock or the like) will occur. If it is too late, it will take time from the gear-in operation to the occurrence of creep, and the driver will not know when to depress the accelerator (large time lag). Therefore, in order to achieve both the clutch connection shock and the shortening of the connection time, the play area until the clutch starts to be engaged is suddenly contacted, and when the clutch starts to be connected, the connection speed is switched and the control is performed slowly. ing.
[0004]
More specifically, when the working fluid pressure for driving the clutch to connect / disconnect is changed according to the duty pulse output from the electronic control unit, and the clutch is connected from the disengaged state, the clutch is first connected. A predetermined starting duty is output from the electronic control unit so that it is largely contacted to the vicinity of the position (this is referred to as conventional one-shot contact control), and then a predetermined gradual engagement duty that causes the clutch to be loosely connected thereafter is determined every predetermined time. Output from the electronic control unit.
[0005]
The clutch transmission start position, in other words, the torque transmission start point at which the predetermined torque can be transmitted first is called a torque point, and this torque point is learned by the control unit and used as a connection speed switching point. Yes. The reason why the torque point is used as the learning value is that there are variations or individual differences in the clutch due to manufacturing errors or the like, and the torque point is different for each clutch.
[0006]
[Problems to be solved by the invention]
By the way, in the conventional one-shot contact control, in order to reliably prevent the clutch from being connected beyond the torque point, the start duty is set to a value before the torque point, and the initial invalid stroke and clutch of the clutch piston are set. Since it is necessary to wait for the pressure rise delay, the output state of the start duty is maintained for a certain waiting time.
[0007]
However, in this method, when the waiting time elapses, the clutch always stops at the position before the torque point and the clutch is surely prevented from being excessively engaged, but it is necessary to wait for the waiting time, which further reduces the clutch connection time. I could n’t.
[0008]
In view of the above problems, the present invention has been invented, and an object thereof is to further reduce the clutch engagement time.
[0009]
[Means for Solving the Problems]
The present invention relates to a method for controlling connection / disconnection of a clutch by changing a working fluid pressure for driving connection / disconnection of a wet friction clutch according to a duty pulse output from the electronic control unit. When the torque point duty corresponding to the working fluid pressure reaching the torque point is learned and the clutch is connected from the disengaged state, first , a predetermined start duty that is a value closer to the clutch than the torque point duty is set as follows : The electronic control unit outputs a predetermined slow engagement duty that is output from the electronic control unit during the output time set so that the clutch reaches a predetermined position before the torque point, and then the clutch is loosely connected every predetermined time. Is output from
[0010]
According to this, since the value of the start duty is closer to the conventional side, the operating speed of the clutch becomes faster. On the other hand, the output time of the start duty, that is, the waiting time is determined by an actual machine test in accordance with the value of the start duty. As a result, the same one-contact mode as in the prior art can be realized in a shorter time than in the past, and the clutch engagement time can be further shortened.
[0011]
Here, it is preferable that the value of the start duty is a value corresponding to or near the complete engagement of the clutch.
[0012]
One or both of the start duty value and the output time are preferably corrected based on the temperature of the working fluid.
[0013]
The wet friction clutch may be provided in series between the engine and the transmission and downstream of the fluid coupling that can be locked up.
[0014]
On the other hand, the present invention is an apparatus for controlling connection / disconnection of a clutch by changing a working fluid pressure for driving connection / disconnection of a wet friction clutch according to a duty pulse output from the electronic control unit. When learning the torque point duty corresponding to the working fluid pressure that reaches the torque point of the clutch and connecting the clutch from the disengaged state, first , a predetermined start duty that is a value closer to the clutch than the torque point duty Is output from the electronic control unit for an output time set so that the clutch reaches a predetermined position before the torque point, and thereafter, a predetermined slow engagement duty such that the clutch is loosely connected is electronically output every predetermined time. Output from the control unit.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings.
[0016]
FIG. 1 shows a power transmission device for a vehicle in this embodiment. As shown in the figure, a clutch mechanism 1 is provided between the engine E and the transmission T / M. The clutch mechanism 1 includes a fluid coupling (fluid coupling) 2 provided on the upstream side in the power transmission direction, and a downstream side thereof. And a wet multi-plate clutch 3 as a wet friction clutch provided in series. The fluid coupling here is a broad concept including a torque converter, and the torque converter is also used in the present embodiment. The vehicle to which this apparatus is applied is a relatively large vehicle such as a truck. Engine E is a diesel engine.
[0017]
The fluid coupling 2 is interposed between the pump 4 connected to the output shaft (crankshaft) of the engine, the turbine 5 facing the pump 4 and connected to the input side of the clutch 3, and the turbine 5 and the pump 4. The stator 6 is provided. A lock-up clutch 7 is provided in parallel with the fluid coupling 2, which connects and disconnects the pump 4 and the turbine 5 to enable the fluid coupling 2 to be locked up. The wet multi-plate clutch 3 has an input side connected to the turbine 5 via the input shaft 3a, an output side connected to the input shaft 8 of the transmission T / M, and the fluid coupling 2 and the transmission T / M. Connect and disconnect.
[0018]
The transmission T / M includes an input shaft 8, an output shaft 9 disposed coaxially with the input shaft 8, and a counter shaft 10 disposed in parallel therewith. An input main gear 11 is provided on the input shaft 8. The output shaft 9 is supported by a first speed main gear M1, a second speed main gear M2, a third speed main gear M3, a fourth speed main gear M4, and a reverse main gear MR. A main gear M6 is fixed. The counter shaft 10 has an input sub gear 12 meshed with the input main gear 11, a first speed sub gear C1 meshed with the first speed main gear M1, a second speed sub gear C2 meshed with the second speed main gear M2, and 3 A third speed sub gear C3 meshing with the speed main gear M3, a fourth speed sub gear C4 meshing with the fourth speed main gear M4, and a reverse sub gear CR meshing with the reverse main gear MR via the idle gear IR are fixed. In addition, a sixth-speed sub gear C6 that meshes with the sixth-speed main gear M6 is pivotally supported.
[0019]
According to this transmission T / M, when the sleeve S / R1 spline-engaged with the hub H / R1 fixed to the output shaft 9 is spline-engaged with the dog DR of the reverse main gear MR, the output shaft 9 is reversely rotated. When the sleeve S / R1 is spline-engaged with the dog D1 of the first-speed main gear M1, the output shaft 9 rotates at the first speed. Then, when the sleeve S / 23 spline-engaged with the hub H / 23 fixed to the output shaft 9 is spline-engaged with the dog D2 of the second-speed main gear M2, the output shaft 9 rotates at the second speed, and the sleeve When S / 23 is spline-engaged with the dog D3 of the third speed main gear M3, the output shaft 9 rotates at the third speed.
[0020]
When the sleeve S / 45 that is spline-engaged with the hub H / 45 fixed to the output shaft 9 is spline-engaged with the dog D4 of the 4-speed main gear M4, the output shaft 9 rotates at a speed equivalent to 4th speed, and the sleeve When S / 45 is spline-engaged with the dog D5 of the input main gear 11, the output shaft 9 rotates at the fifth speed (direct connection). When the sleeve S6 splined to the hub H6 fixed to the countershaft 10 is splined to the dog D6 of the sixth speed sub gear C6, the output shaft 9 rotates at the sixth speed. Each of the sleeves is manually operated by a shift lever in the cab through a shift fork and a shift rod (not shown). That is, the transmission T / M is a manual type.
[0021]
The wet multi-plate clutch 3 has a normal configuration. That is, although not shown in the drawings, in the clutch casing filled with oil, the clutch plates are alternately meshed with each other on the input side and the output side, and the clutch plates are pressed against each other by the clutch piston or released. Then, the clutch is connected and disconnected. Referring to FIG. 2, the clutch piston 27 is always biased to the disengagement side by the clutch spring 28, and the clutch 3 is engaged when a hydraulic pressure exceeding this is applied to the clutch piston 27. The clutch fastening force or the torque capacity of the clutch is increased according to the applied hydraulic pressure.
[0022]
Next, a hydraulic pressure supply device for supplying hydraulic pressure to the wet multi-plate clutch 3 will be described. As shown in FIG. 2, the oil in the oil tank 13 is sucked and discharged by the hydraulic pump OP through the filter 14, and the discharge pressure is adjusted by the relief valve 15 to create a constant line pressure PL. The oil of the line pressure PL is controlled (pressure-reduced) and sent to the clutch 3. For this reason, two valves, a clutch control valve CCV and a clutch solenoid valve CSV, are used. That is, a pilot operated hydraulic control system is employed in which the clutch control valve CCV connected to the main hydraulic line is opened and closed according to the pilot hydraulic pressure Pp sent from the clutch solenoid valve CSV. The magnitude of the pilot oil pressure Pp is changed according to a duty pulse output from an electronic control unit (hereinafter referred to as ECU) 16.
[0023]
That is, the clutch solenoid valve CSV is an electromagnetic valve having an electromagnetic solenoid, which opens and closes according to ON / OFF of a duty pulse output from the ECU 16 and is always supplied with a line pressure PL. Then, the pilot oil pressure Pp corresponding to the duty (duty ratio) D of the duty pulse is output.
[0024]
The clutch control valve CCV is a spool valve that is controlled steplessly based on the pilot oil pressure Pp and is not electronically controlled. That is, the built-in spool is stroked to the open side according to the magnitude of the pilot oil pressure Pp, thereby adjusting the line pressure PL as appropriate and feeding it to the clutch 3 as the clutch pressure Pc. Thus, as a result, the hydraulic pressure supplied to the clutch 3 is duty-controlled by the ECU 16.
[0025]
An accumulator 17 is provided in the middle of the path connecting the clutch solenoid valve CSV and the clutch control valve CCV.
[0026]
FIG. 3 shows a characteristic diagram of the hydraulic pressure supply device. The horizontal axis represents the duty D of the duty pulse output from the ECU 16, more specifically, the ON duty indicating the ratio of the solenoid ON time in the basic control cycle (20 msec in this embodiment). In this embodiment, the clutch is completely engaged when the duty D is 0 (). This is to make it possible to maintain the running of the vehicle by setting the clutch in the connected state even when no power is supplied to the clutch solenoid valve CSV due to an electrical system failure or the like (so-called OFF stack state). .
[0027]
As shown in the figure, the larger the duty D is, the smaller the contact is, and the smaller the duty is. As the value of the duty D decreases, the value of the pilot hydraulic pressure Pp output from the clutch control valve CCV increases proportionally, and accordingly, the hydraulic pressure supplied to the clutch, that is, the clutch pressure Pc, and the torque capacity of the clutch 3 Tc tends to increase proportionally. Although the valve opening V of the clutch control valve CCV is 3 positions in the figure, the spool valve is slightly stroked at an intermediate opening (valve opening 0 mm in the figure) other than fully open and fully closed in practice. The pressure Pc can be changed continuously.
[0028]
Although there is a control system for the lock-up clutch 7 in this embodiment, the description is omitted here because it is not directly related to the present invention. The configuration of the hydraulic control system is substantially the same as the hydraulic control system of the wet multi-plate clutch 3.
[0029]
Next, an electronic control device for electronically controlling the power transmission device will be described with reference to FIG. In addition to the clutch solenoid valve CSV, various switches and sensors are connected to the ECU 16 in order to electronically control the apparatus. This includes an engine speed sensor 18 for detecting the engine speed, a turbine speed sensor 19 for detecting the speed on the input side of the clutch 3, that is, the speed of the turbine 5, the speed of the transmission T / M, representative Specifically, a transmission rotation sensor 20 for detecting the rotation speed of the input auxiliary gear 12 and a vehicle speed sensor 21 for detecting the vehicle speed are included. These sensors are also shown in FIG. In particular, the ECU 16 calculates the rotation speed of the input shaft 8 from the output of the transmission rotation sensor 20 and the gear ratio of the input main gear 11 and the input sub-gear 12 and sets this as the output-side rotation speed of the clutch 3. That is, the means for detecting the clutch output side rotational speed is the transmission rotation sensor 20.
[0030]
The ECU 16 also detects a parking brake switch 22 for detecting whether the parking brake is operating, a foot brake switch 23 for detecting whether the foot brake is operating, and a gear position of the transmission. A gear position sensor 24 is also connected.
[0031]
A knob switch 25 is also connected to the ECU 16. That is, in this embodiment, in order to detect the start timing of the shifting operation by the driver or to determine the timing to start the clutch disengagement, the shift knob of the cab can slightly swing in the shift direction with respect to the lever. The knob switch 25 is provided between the lever and the shift knob. When the shift operation is performed by the driver, if the shift knob is swung prior to the operation of the lever, the knob switch 25 is turned ON, and the clutch disengagement is started with this as a signal. The specific configuration is the same as that shown in JP-A-11-236931.
[0032]
Further, the power transmission device of the present embodiment is provided with a slope start assist device (HSA; Hill Start Aid) as shown in the same publication, and in the cab to manually turn on / off the device. An HSA switch 26 is provided, and the HSA switch 26 is connected to the ECU 16.
[0033]
Next, the operation and control method of the power transmission device according to this embodiment will be described.
[0034]
In this power transmission device, the power of the engine E is transmitted in the order of the fluid coupling 2, the wet multi-plate clutch 3, and the transmission T / M. In principle, the lock-up clutch 7 is always turned on (contacted) after starting, and turned off (disconnected) when stopping and starting. Therefore, when starting, the creep of the fluid coupling 2 can be used like an AT car, and the control becomes simpler than that in which the friction clutch is electronically controlled to start. Can prevent loss. The wet multi-plate clutch 3 is connected / disconnected at every shift. This is the same as a normal MT car.
[0035]
Here, the connection / disconnection control of the lock-up clutch 7 will be described in detail. The lock-up clutch 7 is engaged at a predetermined speed (approximately 10 km / h in the present embodiment) which is a relatively low vehicle speed. More precisely, the lock-up clutch engagement is established when the input shaft rotation speed reaches a predetermined rotation speed (uniformly 900 rpm in the present embodiment) or more at each gear stage. When the vehicle starts at the starting stage (for example, the second speed, which is a frequently used starting stage) and the input shaft speed reaches the predetermined speed (900 rpm), the lockup clutch is engaged, and the vehicle speed at this time is low ( About 10km / h).
[0036]
First, the operation at the start of the vehicle, that is, the case of a garage shift will be described. Suppose that the driver tries to start and operates the shift lever to the starting stage while the vehicle is stopped in the gear neutral and brake (including both foot brake and parking brake) operating states. Then, in the shift lever, the knob switch 25 is turned on by the swing of the shift knob prior to the operation of the lever, and the clutch 3 is cut off as a signal. When the shift lever is subsequently operated, the transmission T / M is geared into the starting stage, and when this is detected by the gear position sensor 24, the clutch 3 is connected. Since the turbine 5 is stopped from the drive wheel side by this connection, the pump 4 slides with respect to the turbine 5 and a creep force is generated. Therefore, if the brake is released or the accelerator is depressed, the vehicle starts to move.
[0037]
Next, the operation at the time of shifting while the vehicle is running, that is, the case of shifting up or down will be described. When the vehicle is traveling at a predetermined gear stage, it is assumed that the driver tries to shift gear and operates the shift lever to the next gear stage. Then, prior to the operation of the lever, the shift knob swings, the knob switch 25 is turned on, and the clutch 3 is disconnected with this as a signal. Then, when the shift lever is continuously operated, the transmission T / M is geared into the next shift stage, and when this is detected by the gear position sensor 24, the clutch 3 is connected. This completes the shift. During this shift, the lockup clutch 7 remains ON, and the engine power is transmitted to the clutch 3 as it is. The clutch control method during traveling will be described in detail with reference to FIGS. FIG. 5 shows the case of shifting up, and FIG. 6 shows the case of shifting down. First, the case of upshifting will be described.
[0038]
As shown in FIG. 5, when the knob switch is turned on (t1), the clutch is completely disengaged, and when the shift gear is operated to shift to the next gear stage, the clutch connection is started (t2).
[0039]
First, one-shot contact control is executed. In particular, the one-shot contact control according to the present invention is different from the conventional one. That is, the start duty (one-shot duty) Dst that causes the clutch 3 to be greatly engaged to the fully connected position beyond the torque point is output from the ECU 16 during the waiting time Δtst that is shorter than the conventional one. Here, the start duty Dst = 0 (%) and the waiting time Δtst = 0.1 sec.
[0040]
In the conventional one-contact control, the start duty Dst = about 60 (%) and the waiting time Δtst = 0.5 sec. The reason why the start duty Dst is set to about 60 (%) is that a torque point duty, which will be described later, is about 50%, and the clutch needs to be surely stopped before the torque point, and the waiting time Δtst is set to 0.5 sec. This is because this time is required to finish the initial invalid stroke of the clutch and the increase of the clutch pressure at the start duty.
[0041]
On the other hand, in the one-shot contact control according to the present invention, the starting duty on the contact side is output for a shorter time than before. In this way, since the duty value is on the contact side, the amount of oil applied to the clutch increases and the clutch can be connected more quickly. On the other hand, since the clutch itself needs to be stopped before the torque point as in the prior art, such a waiting time Δtst is set by an actual machine test. As a result, the same one-shot contact mode as in the prior art can be realized in a shorter time than in the prior art, and the clutch engagement time can be further shortened while preventing clutch contact shock.
[0042]
In particular, as in the present embodiment, it is preferable to set the start duty Dst to the closest value (completely connected equivalent value) = 0 (%). This is because the highest clutch engagement speed can be obtained. Similarly, a value in the vicinity thereof (for example, 10 (%)) is also preferable. However, the value of the start duty Dst can be arbitrarily selected as long as it is a value closer to the conventional side. The value of the start duty Dst may be determined from a map or the like based on the vehicle operating state. Since the waiting time Δtst is also set according to the model, it is not limited to 0.1 sec. This value can also take an arbitrary value.
[0043]
The one-shot contact control is open loop control. The torque point of the clutch is a learning value and is stored in the ECU 16 with the duty value. For example, as shown in FIG. 3, the torque point learning value is a duty D = 50 () indicating a torque capacity Tcm = about 200 (Nm). If the torque capacity diagram shifts as shown by a broken line due to variations in the clutch or the like, the torque point learning value also changes accordingly.
[0044]
Now, after the clutch one-shot engagement control, the control shifts to clutch loose engagement control (t3). That is, the slow engagement duty Dk that causes the clutch 3 to be loosely engaged is output from the ECU 16 at predetermined time intervals. The predetermined time here is equal to the control cycle Δt = 20 msec in this embodiment. However, it may be equal to a plurality of control cycles nΔt. Hereinafter, this predetermined time is referred to as a slow contact cycle.
[0045]
In this gradual engagement control, the value of the gradual engagement duty for each gradual engagement cycle is determined based on the rotational difference on the input / output side of the clutch. The value Ne of the engine speed detected by the engine speed sensor 18 is used as the clutch input side speed. This is because the lock-up clutch is engaged during traveling, and it can be considered that the clutch input side rotational speed = engine rotational speed. As the clutch output side rotational speed, the value Ni of the input shaft rotational speed calculated from the output of the transmission rotation sensor 20 and the gear ratio as described above is used.
[0046]
Since the shift is up here, the engine speed Ne is higher than the input shaft speed Ni as shown in FIG. Therefore, the rotation difference ΔN is calculated by subtracting the input shaft rotation speed Ni from the engine rotation speed Ne (ΔN = Ne−Ni).
[0047]
As shown in FIG. 8, the value of the step duty Ds with respect to the rotation difference ΔN is set in a map format for each gear stage of the transmission. This step duty calculation map is stored in the ECU 16.
[0048]
Specific contents of the clutch loose engagement control are as follows. First, the slow contact duty Dk3 as an initial value is output in the slow contact cycle at time t3. The value of the slow contact duty Dk3 is slightly closer to the torque point learning value. Then, the rotation difference ΔN3 at this time is calculated, and the step duty Ds3 is determined from the current gear and the value of ΔN3 according to the map of FIG. In the slow contact cycle at time t4, which is the next control round, a value obtained by subtracting the step duty Ds3 from the previous slow contact duty Dk3 is set as the current slow contact duty Dk4, which is output from the ECU 16. Hereinafter, similarly, the rotation difference ΔNn is calculated at the slow contact period at time tn (n = 4, 5, 6,...), The step duty Dsn is determined according to the map of FIG. In the slow contact cycle of tn + 1, the step duty Dsn is subtracted from the previous slow contact duty Dkn to obtain the current slow contact duty Dkn + 1, which is output from the ECU 16. By repeating such control, the clutch is gradually connected, and the rotational difference ΔN gradually decreases.
[0049]
Note that the calculation cycle of the step duty Ds and the control cycle Δt are not necessarily equal. At this time, the slow contact duty Dk is updated every time the step duty Ds is calculated, and this update cycle becomes the slow contact cycle.
[0050]
In this way, when the predetermined slow contact end condition is satisfied, the slow contact control is terminated, and the clutch rapid contact control is shifted to. The slow engagement end condition of the present embodiment is that the rotation difference ΔN becomes a small value of 150 rpm or less, or that the duty output from the ECU 16 reaches the slow contact end duty De that can be considered that the clutch is sufficiently connected. In the clutch quick contact control, a quick contact duty = 0 is output for a predetermined time = 0.3 sec. Thereafter, clutch complete engagement control is performed, and clutch engagement control is terminated. Similarly, in the clutch complete contact control, the complete contact duty = 0 is output for a predetermined time = 1 sec.
[0051]
Next, the case of downshift will be described with reference to FIGS. When shifting down, it is almost the same as when shifting up. The difference is that when the gear is downshifted, as shown in FIG. 6 (d), the input shaft rotational speed Ni is higher than the engine rotational speed Ne, so the calculation of the rotational difference ΔN is also reversed, and the rotational difference ΔN is This is a point calculated by subtracting the engine speed Ne from the speed Ni (ΔN = Ni−Ne). Further, the value of the step duty Ds is set separately from the case of upshifting, and specifically, a step duty calculation map for downshifting as shown in FIG. 9 is prepared separately. In this map, the values in the map are more suitable for downshifting. The contents of the other clutch contact control are the same as described above, and in the one-shot contact control, the start duty Dst = 0 (%) is output as a waiting time Δtst = 0.1 sec.
[0052]
Next, the case of the garage shift will be described with reference to FIGS. In FIG. 7, before the time t1, the vehicle is stopped before starting, the gear neutral, the brake operating state, the engine idling, the wet multi-plate clutch 3 is connected, the lock-up clutch 7 is disconnected, and the engine output is the fluid coupling 2, It is transmitted to the countershaft 10 and the main gear M1... Of the transmission T / M via the wet multi-plate clutch 3. This is because the mission oil stored in the transmission T / M is agitated by the rotation of the sub-gears 12. At this time, the engine speed Ne, the turbine speed Nt, and the input shaft speed Ni are all equal.
[0053]
When the driver performs a gear shifting operation from this state, the knob switch is first turned ON and the clutch is completely disengaged (t1). As a result, the input shaft rotational speed Ni falls, and when the gear is engaged in the starting stage, the clutch is engaged. Is started (t2). Simultaneously with the gear-in, the input shaft 8 is stopped by a brake from the drive wheel side, so that the rotation speed becomes zero.
[0054]
The first one-contact control is the same as described above. That is, the start duty Dst = 0 (%) is output at a constant waiting time Δtst = 0.1 sec. Next, the slow contact control similar to the above is executed. In the loose contact control, the step duty Ds is read from the garage shift dedicated map shown in FIG. In this loose connection control, the turbine 5 is gradually braked from the drive wheel side in accordance with the clutch connection, so the turbine rotational speed Nt gradually decreases.
[0055]
Therefore, when the rotational difference ΔNet (= Ne−Nt) between the engine rotational speed Ne and the turbine rotational speed Nt reaches a predetermined value Nm (300 rpm in the present embodiment), it is considered that the clutch is substantially substantially connected, and is slow. The contact control is terminated, and thereafter, the clutch sudden contact control and the clutch complete contact control similar to those described above are performed, and the connection control is terminated.
[0056]
By the way, each connection control described above is performed when the clutch oil is at room temperature. On the other hand, when the clutch oil is at a low temperature, it is preferable to correct one or both of the start duty Dst and the waiting time Δtst.
[0057]
That is, the wet multi-plate clutch 3 is easily connected when the oil temperature of the clutch oil is low. This is because when the oil temperature is low, the clutch pressure applied to the clutch piston 27 increases, the oil viscosity between the clutch plates increases and torque is transmitted more, and the hydraulic circuit such as the clutch control valve CCV and the clutch solenoid valve CSV. This is because the internal leak in the component is reduced, and the amount of oil to the clutch is increased accordingly. In the present embodiment, the oil for operation and control of the fluid coupling 2, the lockup clutch 7 and the wet multi-plate clutch 3 are common, and torque converter oil is used, and a sensor (not shown) detects this oil temperature. Is provided). This oil and transmission mission oil are used separately.
[0058]
In the above example, the start duty Dst is set to 0 (%) and the waiting time Δtst is set to 0.1 sec on the assumption that the oil temperature is normal temperature. However, if the same value is used even at a low temperature, the clutch is too connected at the end of one-shot contact, and a contact shock occurs.
[0059]
Therefore, when the oil temperature is low, it is preferable to correct one or both of the start duty Dst and the waiting time Δtst. FIG. 11 shows an example of a garage shift. In this illustrated example, the waiting time Δtst is the same (0.1 sec), and only the start duty Dst is corrected to 60 (%), which is a more disconnected value. As a result, the amount of oil applied to the clutch is reduced, the clutch control speed is reduced by the amount that the clutch is easily connected, and the one-shot contact can be completed in the same short time as described above while preventing contact shock. As a result, it is possible to obtain a clutch connection feeling that is particularly suitable for starting immediately after startup in cold weather. Since the clutch characteristics of the wet type multi-plate clutch 3 change greatly when the clutch oil temperature is 0 ° C. or lower, the correction is performed when the oil temperature is 0 ° C. or lower. The start duty Dst is set to 0 (%). It should be noted that the initial value Dk3 of the slow contact duty after one contact is slightly close to the torque point learning value as described above. The same correction is possible in the case of upshifting and downshifting.
[0060]
There are various other correction methods. For example, it is possible to make the start duty Dst the same and correct the waiting time Δtst in a shorter time. It is also possible to perform correction by balancing both the start duty Dst and the waiting time Δtst. It is possible to adopt a value other than 0 ° C. for the correction oil temperature threshold. One or both of the start duty Dst and the waiting time Δtst can be corrected according to the detected clutch oil temperature according to a map or the like.
[0061]
As described above, according to the present invention, in the clutch one-shot control, the start duty on the side closer to the clutch that exceeds the torque point is applied for a shorter time than the conventional one, so that the one-shot is prevented while preventing the contact shock. The contact control time can be reduced, and the clutch connection time can be further reduced as a whole. Also, since one or both of the start duty and waiting time are corrected based on the clutch oil temperature, the same clutch engagement state as that at normal temperature can be obtained even when the oil temperature is low during cold weather, and the optimum clutch connection feeling is always obtained. can get.
[0062]
The embodiment of the present invention is not limited to the above. In the above embodiment, the duty decreasing direction is the clutch engagement direction, but this may be reversed. The wet friction clutch referred to in the present invention is a multi-plate type in the above embodiment, but may be a single-plate type, for example. In addition, the fluid pressure referred to in the present invention is a hydraulic pressure in the above embodiment, but other fluid pressures such as pneumatic pressure may be used. The transmission according to the present invention is a constant mesh type manual transmission in the above-described embodiment. For example, a constant mesh type automatic transmission (with an automatic shifter) or a planetary gear type automatic transmission such as an AT car is used. You can use a machine. The engine can be of any type such as diesel or gasoline. The present invention is also applicable to a power transmission device that does not use a fluid coupling.
[0063]
【The invention's effect】
As described above, according to the present invention, an excellent effect that the clutch engagement time can be further shortened is exhibited.
[Brief description of the drawings]
FIG. 1 is a skeleton diagram showing a power transmission device for a vehicle according to an embodiment of the present invention.
FIG. 2 is a hydraulic circuit diagram showing a hydraulic pressure supply device according to an embodiment of the present invention.
FIG. 3 is a characteristic diagram of the hydraulic pressure supply device according to the embodiment of the present invention.
FIG. 4 is a configuration diagram illustrating an electronic control device according to an embodiment of the present invention.
FIG. 5 is a time chart showing the contents of clutch connection control according to the embodiment of the present invention, in the case of upshifting.
FIG. 6 is a time chart showing the contents of clutch connection control according to the embodiment of the present invention, in the case of downshifting.
FIG. 7 is a time chart showing the contents of clutch connection control according to the embodiment of the present invention, and is a case of a garage shift.
FIG. 8 is a step duty calculation map at the time of up-shifting according to the embodiment of the present invention.
FIG. 9 is a step duty calculation map at the time of downshift according to the embodiment of the present invention;
FIG. 10 is a step duty calculation map during a garage shift according to an embodiment of the present invention.
FIG. 11 is a time chart showing the contents of clutch connection control according to the embodiment of the present invention, and is a case of a garage shift when the clutch oil temperature is low.
[Explanation of symbols]
2 Fluid coupling 3 Wet multi-plate clutch 7 Lock-up clutch 16 Electronic control unit (ECU)
E Engine T / M Transmission CSV Clutch solenoid valve CCV Clutch control valve D Duty Dst Start duty Dk Slow engagement duty Δt Control time Δtst Waiting time

Claims (5)

The working fluid pressure for engaging and disengaging drive the wet friction clutch to a method for engaging and disengaging control of the clutch by varying in accordance with the duty pulse output from an electronic control unit, the torque point of the clutch to the electronic control unit When the torque point duty corresponding to the reached working fluid pressure is learned and the clutch is engaged from the disengaged state, first, the clutch has a predetermined start duty that is a value closer to the clutch than the torque point duty. Output from the electronic control unit for an output time set to reach a predetermined position in front, and then output a predetermined slow engagement duty from the electronic control unit every predetermined time so that the clutch is loosely engaged. A clutch control method characterized by the above.   2. The clutch control method according to claim 1, wherein the value of the start duty is a value corresponding to or near the complete engagement of the clutch.   The clutch control method according to claim 1, wherein one or both of the start duty value and the output time are corrected based on a temperature of the working fluid.   4. The clutch control method according to claim 1, wherein the wet friction clutch is provided in series between the engine and the transmission and downstream of the fluid coupling capable of being locked up. The working fluid pressure for engaging and disengaging drive the wet friction clutch a device for engaging and disengaging control of the clutch by varying in accordance with the duty pulse output from an electronic control unit, the torque point of the clutch to the electronic control unit When the torque point duty corresponding to the reached working fluid pressure is learned and the clutch is engaged from the disengaged state, first, the clutch has a predetermined start duty that is a value closer to the clutch than the torque point duty. Output from the electronic control unit for an output time set to reach a predetermined position in front, and then output a predetermined slow engagement duty from the electronic control unit every predetermined time so that the clutch is loosely engaged. A clutch control device.

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