JP3951419B2 - Shift control device for automatic transmission - Google Patents

Shift control device for automatic transmission Download PDF

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Publication number
JP3951419B2
JP3951419B2 JP06105798A JP6105798A JP3951419B2 JP 3951419 B2 JP3951419 B2 JP 3951419B2 JP 06105798 A JP06105798 A JP 06105798A JP 6105798 A JP6105798 A JP 6105798A JP 3951419 B2 JP3951419 B2 JP 3951419B2
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Japan
Prior art keywords
speed
clutch
shift
time
point
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Expired - Fee Related
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JP06105798A
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Japanese (ja)
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JPH11257482A (en
Inventor
秀洋 大庭
一美 星屋
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トヨタ自動車株式会社
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16HGEARING
    • F16H3/00Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion
    • F16H3/006Toothed gearings for conveying rotary motion with variable gear ratio or for reversing rotary motion power being selectively transmitted by either one of the parallel flow paths

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shift control apparatus suitable for application when performing a downshift during coasting in an automatic transmission that performs a shift of a so-called clutch-to-clutch.
[0002]
[Prior art]
In general, when the driver closes the throttle opening or coasts away from the vehicle, the downshift is executed when the vehicle speed drops and crosses the downshift point. Conventionally, shifting is performed by a preset coast-down shifting point. When this coast downshift is realized by so-called clutch-to-clutch shift, the high speed stage clutch hydraulic pressure is lowered and the low speed stage clutch hydraulic pressure is increased simultaneously to switch the engagement and release of the clutch ( For example, JP-A-6-221347). At this time, since the gear shift is executed in the coast state (the state where power is transmitted from the wheel side to the engine side: driven state), the turbine rotation speed which is supposed to decrease due to the release of the high speed side clutch is reduced. The operation of pulling up to the synchronous rotational speed is performed by engaging the stage side clutch (low speed stage side).
[0003]
However, in order to raise the turbine rotation speed by executing the shift, it takes a time corresponding to the shift time. Therefore, if the vehicle speed is reduced by rapid deceleration during this time, the turbine rotation speed falls below the engine rotation speed, and temporarily There is a risk of switching from the previous driven state to the driving state.
[0004]
Further, in an automatic transmission having a synchro mechanism, if the deceleration is large, there is a possibility that the next shift point may be crossed before there is a time margin for switching the synchro.
[0005]
Therefore, the shift point in this type of coast downshift is a normal shift so that the driven state can always be maintained without causing such a problem even during sudden deceleration to some extent in consideration of the shift time and synchro travel time. It is set on the higher vehicle speed side than the point.
[0006]
[Problems to be solved by the invention]
However, if the shift point is set on the high vehicle speed side in this way, excessive engine braking force may be generated at a low speed after the shift due to the coast down, and the shift shock is also increased accordingly. A problem occurs.
[0007]
The present invention has been made in view of such a conventional problem. By determining the shift point, which has been basically fixed conventionally, optimally according to the running state, the shift shock is alleviated and smooth. It is an object of the present invention to provide a shift control device for an automatic transmission that makes it possible to obtain an engine brake.
[0009]
[Means for Solving the Problems]
  Claim1The invention described in 1 is an automatic transmission that has a plurality of clutches and a plurality of synchro mechanisms, and that performs a clutch-to-clutch shift that performs a downshift according to a shift point during coasting, and is involved in the initial stage of the clutch-to-clutch shift. In a shift control device for an automatic transmission that performs a first quick fill in which a complete hydraulic pressure supply command is applied to a clutch to be engaged for a predetermined time, a means for obtaining a time during which the synchro mechanism moves when performing a downshift during the coasting; Means for selecting a shift point on the high vehicle speed side from among a means for obtaining the time required for the first quick fill, a shift point based on the time required for the synchro movement, and a shift point based on the time required for the first quick fill. And downshifting during the course according to the selected shift point. ,Above issuesIs a solution.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0011]
FIG. 3 is a diagram schematically showing the overall structure of a twin clutch type four-speed automatic transmission with a torque converter to which the present invention is applied.
[0012]
In FIG. 3, 1 represents an engine, 2 represents a torque converter with a lock-up mechanism, and 3 represents a twin clutch type automatic transmission.
[0013]
The output shaft 10 of the engine 1 is connected to the front cover 20 of the torque converter 2. The front cover 20 is connected to the torque converter output shaft 24 via a pump impeller 21 and a turbine 22 connected via a fluid flow, or via a lock-up clutch 23. The output shaft 24 of the torque converter 2 is connected to an input shaft (transmission input shaft) 30 of the twin clutch type automatic transmission 3 so as to be integrally rotatable. In addition, 25 is a stator and 26 is a one-way clutch.
[0014]
The input shaft 30 is connected to the first clutch input disk C1i of the first clutch C1 and the second clutch input disk C2i of the second clutch C2.
[0015]
The first clutch output shaft C1o of the first clutch C1 and the second clutch output disc C2o of the second clutch C2 are respectively connected to the first clutch output shaft 40 and the second clutch output shaft 50 outside the input shaft 30. Coaxially connected.
[0016]
Further, the auxiliary shaft 60 and the output shaft (transmission output shaft) 70 are arranged in parallel to these shafts.
[0017]
A second speed drive gear I2, a countershaft drive gear Is, and a fourth speed drive gear I4 are fixedly connected to the second clutch output shaft 50.
[0018]
On the other hand, a third speed drive gear I3 is fixedly connected to the first clutch output shaft 40 so as to be adjacent to the fourth speed drive gear I4, and a first speed drive gear I1 is fixedly connected to the torque converter 2 side. ing.
[0019]
The output shaft 70 has a second speed driven gear O2 that is always meshed with the second speed drive gear I2, a fourth speed driven gear O4 that is always meshed with the fourth speed drive gear I4, and a third gear that is always meshed with the third speed drive gear I3. A speed driven gear O3 and a first speed driven gear O1 that is always meshed with the first speed drive gear I1 are rotatably mounted.
[0020]
The first synchronizer (synchronizing mechanism) D1 includes a first hub H1 fixedly connected to the output shaft 70 and a first sleeve S1 slidably mounted on the outer peripheral end thereof in the axial direction. The one sleeve S1 is moved by the first sleeve actuator ACT1 through the first shift fork Y1 and fixedly connected to the first speed clutch gear G1 or the third speed driven gear O3 fixedly connected to the first speed driven gear O1. The first speed driven gear O1 and the third speed driven gear O3 are selectively connected to the output shaft 70 by engaging with the third speed clutch gear G3.
[0021]
Similarly, the second synchro (synchronizing mechanism) D2 comprises a second hub H2 fixedly connected to the output shaft 70, and a second sleeve S2 attached on the outer peripheral end thereof so as to be axially slidable. The second sleeve S2 is moved by the second sleeve actuator ACT2 via the first shift fork Y2, and is moved to the fourth speed clutch gear G4 or the second speed driven gear O2 fixedly coupled to the fourth speed driven gear O4. The fourth speed driven gear O4 and the second speed driven gear O2 are selectively connected to the output shaft 70 by engaging with the fixedly coupled second speed clutch gear G2.
[0022]
The countershaft 60 is provided with a countershaft driven gear Os that is always meshed with the countershaft drive gear Is, and a reverse drive gear IR that is always meshed with the first speed drive gear I1 via the idler gear MR. The countershaft driven gear Os is fixedly connected to the countershaft 60 and always rotates integrally with the countershaft 60. However, the reverse drive gear IR is rotatably mounted, and a third shaft disposed between the two gears. It is selectively connected to the countershaft 60 by a synchro (synchronizing mechanism) D3.
[0023]
The third synchro D3 comprises a third hub H3 fixedly connected to the auxiliary shaft 60, and a third sleeve S3 mounted on the outer peripheral end of the third hub S3 so as to be axially slidable. The reverse drive gear IR is selectively engaged with the countershaft 60 by moving by the third sleeve actuator ACT3 via the third shift fork Y3 and engaging with the reverse clutch gear GR fixedly coupled to the reverse drive gear IR. Rotate together.
[0024]
4A and 4B show the state of engagement of the first clutch C1, the second clutch C2, the first sleeve S1, the second sleeve S2, and the third sleeve S3 at each speed stage. is there.
[0025]
Those marked with ○ are engagements for transmitting power at the gear stage, Δ is a preliminary selection for downshift, and ▽ is a relationship added when a preliminary selection for upshift is made. Show The engagement added by the preliminary selection does not contribute to the transmission of power at the shift stage.
[0026]
For example, at the first speed, the first clutch C1 is engaged, and the first clutch output shaft 40 coupled to the first clutch output disk C1o rotates together with the first speed drive gear I1 and the third speed drive gear I3. The first speed driven gear O1, which is always meshed with the first speed drive gear I1, rotates, and then the first sleeve S1 is positioned on the first speed clutch gear G1 side, whereby the output shaft 70 is moved to the first hub. Rotates with H1 and the second hub H2 to transmit power.
[0027]
At the second speed, the second clutch C2 is engaged, and the second clutch output shaft 50 coupled to the second clutch output disk C2o is the second speed drive gear I2, the second clutch output shaft 50, the fourth speed drive gear. The second speed driven gear O2 which rotates together with I4 and the countershaft drive gear Is and always meshes with the second speed drive gear I2 rotates, and then the second sleeve S2 is positioned on the second speed clutch gear G2 side. As a result, the output shaft 70 rotates together with the first hub H1 and the second hub H2, and power is transmitted.
[0028]
At the third speed, the first clutch C1 is engaged, and the first clutch output shaft 40 coupled to the first clutch output disk C1o rotates together with the first speed drive gear I1 and the third speed drive gear I3. The third speed driven gear O3 that is always meshed with the high speed drive gear I3 rotates, and then the first sleeve S1 is positioned on the third speed clutch gear G3 side as described above, whereby the output shaft 70 is moved. It rotates together with the first hub H1 and the second hub H2 to transmit power.
[0029]
At the fourth speed, the second clutch C2 is engaged, and the second clutch output shaft 50 engaged with the second clutch output disk C2o is the second speed drive gear I2, the second clutch output shaft 50, the fourth speed drive. The fourth speed driven gear O4 that rotates together with the gear I4 and the countershaft drive gear Is and is always meshed with the fourth speed drive gear I4 rotates, and then the second sleeve S2 is positioned on the fourth speed clutch gear G4 side. As a result, the output shaft 70 rotates together with the first hub H1 and the first hub H2, and power is transmitted.
[0030]
In the reverse speed, the second clutch C2 is engaged, and the second clutch output shaft 50 coupled to the second clutch output disk C2o is the second speed drive gear I2, the second clutch output shaft 50, the fourth speed drive gear I4, The countershaft 60 rotates through the countershaft driven gear Os that rotates together with the countershaft drive gear Is and always meshes with the countershaft drive gear Is, and the third sleeve S3 is positioned on the reverse clutch gear GR side. As a result, the reverse drive gear IR rotates, and as a result, the first speed driven gear O1 rotates via the reverse idler gear MR, and then the first sleeve S1 is positioned on the first speed clutch gear G1 side. The output shaft 70 rotates together with the first hub H1 and the second hub H2, and power is transmitted.
[0031]
The gears between the respective gears are engaged by moving the sleeve necessary for completing the transmission path of the gear after the gear shift, and then releasing one of the clutches used before the gear shift. This is done by engaging the other clutch used after the shift and moving and releasing the sleeve that completes the transmission path of the shift stage before the shift.
[0032]
For example, in the shift from the second speed to the third speed, the first clutch C1 is engaged while the first sleeve S1 is moved to engage with the third clutch gear G3 and the second clutch C2 is released. Then, the second sleeve S2 is moved so as to be released from the engagement with the second speed clutch gear G2.
[0033]
In this embodiment, as shown in FIG. 4B, by predicting the next shift stage from the current driving environment (for example, the vehicle speed) and engaging the corresponding synchro mechanism in advance, Control is performed so that clutch switching control is immediately entered when a shift is determined (described later).
[0034]
Engagement and disengagement control (clutch-to-clutch switching control) of the first clutch C1 and the second clutch C2 is performed by the first clutch / clutch connected to the first clutch input disk C1i and the second clutch input disk C2i, respectively. A plate (not shown), a second clutch / clutch plate (not shown) are driven by a first clutch piston (not shown) and a second clutch piston (not shown) driven by hydraulic pressure. This is done by frictionally engaging a first clutch / clutch plate (not shown) and a second clutch / clutch plate (not shown) connected to the two-clutch output disk C2o.
[0035]
The piston is driven by controlling the supply and discharge of the hydraulic oil supplied from the hydraulic supply source OP in FIG. 3 to the piston oil chamber, and the first clutch supply hydraulic control valve VC1 and the second clutch supply hydraulic control valve VC2. Is controlled by an electronic control unit (hereinafter referred to as ECU) 100.
[0036]
The first sleeve S1, the first sleeve S2, and the third sleeve S3 are moved by the first sleeve actuator ACT1, the second sleeve actuator ACT2, and the third sleeve actuator ACT3, respectively, as described above.
[0037]
Although a detailed description of the structure of each sleeve actuator is omitted, the piston to which the shift fork is connected is moved in a desired direction, and hydraulic oil supplied from the hydraulic supply source OP is formed on both sides of the piston. This is done by controlling the supply and discharge of the piston oil chamber. Therefore, a valve for controlling the supply of hydraulic oil to each piston oil chamber and a valve for controlling the discharge of hydraulic oil from each piston oil chamber are provided, and the ECU 100 controls the opening and closing of these valves.
[0038]
In the present invention, since it is necessary to confirm whether or not each sleeve has made a predetermined movement, the first sleeve actuator ACT1, the second sleeve actuator ACT2, and the third sleeve actuator ACT3 The first, second, and third sleeve position sensors 115 a, 115 b, 115 c for detecting the positions of these are sent to the input interface circuit 101 of the ECU 100.
[0039]
The ECU 100 includes a digital computer, and an input interface circuit 101, an ADC (analog / digital converter) 102, a CPU (microprocessor) 103, a RAM (random access memory) 104, a ROM (read only memory) 105, which are connected to each other. An output interface circuit 106 is provided.
[0040]
The CPU 103 includes a gear position sensor 111 that detects a gear position, a vehicle speed sensor 112 that detects a vehicle speed (a rotation speed of the transmission output shaft), a throttle opening sensor 113 that outputs a throttle opening, and a rotation speed of the input shaft 30. The input shaft rotation speed sensor 114 for detecting the position of the sensor and the output signals of the sensors such as the sleeve position sensors 115 a, 115 b, 115 c for detecting the position of the sleeve provided in each of the sleeve actuators described above via the input interface circuit 101. Or further via the ADC 102.
[0041]
The CPU 103 generates a signal for controlling the sleeve actuator for moving the sleeves in order to perform the control of the present invention, which will be described later, from the values of the various sensors and the data stored in the ROM 105. Generating a signal for controlling the first clutch supply hydraulic control valve VC1 and the second clutch supply hydraulic control valve VC2 for controlling the clutch of the transmission, and a signal for controlling the lockup hydraulic control valve VL for controlling the lockup clutch; The data is sent to each via the output interface circuit 106.
[0042]
Next, the details of the control will be described in detail.
[0043]
First, an embodiment relating to a downshift during coasting during slow deceleration will be described. FIG. 1 is a time chart showing a shift point setting method in coast downshift control during slow deceleration.
[0044]
In this embodiment, the shift points for all the shifts are sequentially determined and changed from the shift points on the low speed stage side according to the flowchart described later.
[0045]
However, for the sake of easy understanding, first, from the outline of the qualitative work, how the coast downshift is executed based on the determined shift point (by the method described later). explain. The explanation is simplified by assuming that the engine speed NE is constant.
[0046]
This time chart shows the duty ratio for the second clutch C2 for both the fourth speed stage and the second speed stage, the duty ratio for the first clutch C1 for the third speed stage and the first speed stage, and the turbine rotational speed (= transmission). Rotation speed of input shaft 30) NT, first and second synchro D1, D2 switching state, shift output, engine rotation speed NE, synchronous rotation speed DK1, DK2, DK3, DK4 of each shift stage, and target described later The relationship between turbine rotational speeds NTt is shown.
[0047]
In the column of duty ratio and hydraulic pressure in FIG. 1, a thick line indicates the duty ratio, and a thin line indicates the hydraulic pressure. When the duty ratio is 100%, 100% of the line pressure is supplied to the clutches C1 and C2, and when the duty ratio is 0%, the hydraulic pressures of the clutches C1 and C2 are completely drained.
[0048]
As described above, the first clutch C1 functions as the third-speed clutch cl3 and the first-speed clutch cl1, and the second clutch C2 functions as the fourth-speed clutch cl4 and the second-speed clutch. It also functions as a two-stage clutch cl2. For convenience of explanation, the names will be switched as appropriate.
[0049]
The portion shown at time t1 on the left end of FIG. 1 is the state before the gear shifting operation (the fourth gear is established) in which the fourth gear clutch cl4 is fully engaged and the third gear clutch cl3 is completely released. State).
[0050]
From the state of the fourth speed stage, when the turbine rotational speed NT becomes equal to or lower than the downshift point P7 (P43) of the third speed stage in the coast state (the throttle opening is fully closed or nearly fully closed), the downshift is performed. If there is a shift determination to be made, first, at t2, the duty ratio of the fourth speed clutch cl4 is suddenly reduced to release the fourth speed clutch cl4 (not in a fully released state).
[0051]
At the same time, in order to engage the third-speed clutch cl3, the hydraulic pressure of the third-speed clutch cl3 is output at a duty ratio of 100% for the period T1 (an operation called so-called first quick fill), and thereafter (time (From t3) Waiting with the duty ratio lowered to DL1.
[0052]
The duty ratio DL3 is a value at which the third speed clutch cl3 has a capacity.
[0053]
Conventionally, since the engagement of the third speed clutch cl3 is started together with the release of the fourth speed clutch cl4, the turbine rotational speed NT starts to increase from the time t3. In order to maintain the vehicle in the weak engine brake state, the duty ratio DL1 is set so that the turbine rotational speed NT becomes a target rotational speed NTt set to be higher than the engine rotational speed NE by a predetermined value α (α> 0). To control. That is, the duty ratio of the fourth speed clutch cl4 is completely drained (0) at the time t4 when the turbine speed NT (same as the synchronous speed DK4 of the fourth speed at this time) becomes the engine speed NE + the predetermined value α. %) State, and feedback control is performed on the duty ratio of the third speed clutch cl3 so that the turbine rotational speed NT maintains the target rotational speed NTt.
[0054]
On the other hand, when it is detected that the drain timer T2 started counting from time t2 has elapsed (time t5), a command is issued to switch the second synchro D2 from the fourth gear position to the second gear position.
[0055]
Here, the second synchro D2 switching command is started after the drain timer T2 has elapsed, because the second speed clutch cl4 has a little capacity, This is because there is a possibility that the switching of the synchro D2 may be hindered. The movement of the synchro is started, moved and completed as soon as possible without causing any trouble.
[0056]
When it is confirmed that the switching of the second synchro D2 is completed at the time t6, the second speed clutch for a predetermined time T3 is required to re-engage the second speed clutch cl2 (second clutch C2) at the time t7. The duty ratio of cl2 is output 100% (first quick fill is performed), and then the duty ratio is once lowered to DL2 and waited from time t8. This state is continued until the rotational speed of the clutch C1 (the third rotational speed synchronous rotational speed DK3 at this time) reaches the target rotational speed NTt, at which time the duty of the third speed clutch cl3 (first clutch C1) is reached. The ratio is 0% (complete drain).
[0057]
Similarly to the above, since the second speed clutch cl2 (second clutch C2) has a capacity after the time t9, the control for maintaining the turbine rotational speed NT at the target rotational speed NTt thereafter is the second speed. This is realized by feedback control of the step clutch cl2.
[0058]
When it is detected that the hydraulic pressure of the third speed clutch cl3 (first clutch C1) is completely drained at time t10, the first synchro D1 is switched from the third speed position to the first speed position. Be started.
[0059]
When it is confirmed that the switching of the first sync D1 is completed at time t11, the duty ratio of the first gear clutch cl1 (first clutch C1) is again set to 100% for the predetermined time T4 at time t12 (first). When the quick fill is performed) and the rotational speed of the second speed clutch cl2 (second clutch C2) (at this time, the synchronous speed DK2 of the second speed stage) reaches the target rotational speed NTt at time t13, Drain the full-speed clutch cl2 completely.
[0060]
As a result, the hydraulic pressure of the second clutch C2 is completely drained at time t14, and thereafter the control for maintaining the turbine rotational speed NT at the target rotational speed NTt is the duty of the first speed clutch cl1 (first clutch C1). This is done by feedback control of the ratio.
[0061]
Note that, after time t15 when the turbine rotational speed NT reaches the target rotational speed NTt, the hydraulic pressure of the first speed clutch cl1 is feedback-controlled so that the turbine rotational speed NT decreases at a predetermined decreasing speed.
[0062]
At time t16, assuming that the first shift clutch cl1 is completely engaged, this control is stopped, the duty ratio of the first speed clutch cl1 is maintained at 100%, and the vehicle eventually stops at time t17. As will be described later, this time t17 is predicted from the current deceleration in order to determine the shift point, and does not necessarily coincide with the actual stop time.
[0063]
Next, a shift command (shift down) is output at each of the times t2, t7, and t12 (shift point is set). How to determine this shift point (which is also a feature of the present invention) will be described in detail. To do.
[0064]
Here, determination of the 4-3 shift point P43 when shifting from the fourth speed to the third speed while traveling at the fourth speed will be described. Note that the same shift point determination method can be used during traveling at the third speed stage and the second speed stage.
[0065]
The 4-3 shift point from the 4th speed to the 3rd speed is calculated based on the synchronous rotational speed DK4 of the 4th speed, that is, considering the deceleration of the vehicle.
[0066]
In this embodiment, in order to determine the 4-3 change point P43 from the fourth speed to the third speed, first, the shift point P21 from the second speed to the first speed 2-1 is determined. A 2-1 shift point P32 from the third speed to the second speed is determined based on the 2-1 shift point P21, and 4 from the fourth speed to the third speed is determined based on the 3-2 shift point P32. -3 shift point P43 is determined.
[0067]
FIG. 1 shows how to determine a shift point during slow deceleration, and FIG. 2 shows how to determine a shift point during sudden deceleration.
[0068]
First, how to determine the shift point at the time of slow deceleration will be described.
[0069]
The 2-1 shift point P21 from the second speed to the first speed is first detected to be in the coast state, and the time t17 at which the vehicle completely stops is predicted according to the deceleration.
[0070]
Next, a point on the fourth speed synchronous rotation speed DK4 at time t13 at which the second rotation speed synchronous rotation DK2 and the target rotation speed NTt intersect is defined as P0. The time t13 at this point P0 is the time when the duty ratio of the second speed clutch cl2 (second clutch C2) becomes 0% (drain). From this time t13, the first speed clutch cl1 (first clutch C1). ) Is also a point to start feedback control.
[0071]
At time point t13 at point P0, the first speed stage clutch C1 gradually increases its capacity, so that the 2-1 shift point P21 has the first speed stage clutch cl1 (first clutch) from this point P0. It must be before C1) is able to perform the first quick fill and have capacity. In other words, the 2-1 shift point P21 changes to a time at which the first speed clutch cl1 can have the capacity by performing the first quick fill at the synchronous speed DK4 of the fourth speed at the time t13 of the point P0. This is the time t12 when the rotational speed ΔNOF1 to be added is added.
[0072]
Next, how to determine the 3-2 shift point P32 from the third speed to the second speed will be described.
[0073]
Two factors need to be considered for the shift point P32.
[0074]
Between the 2-1 shift point P21 and the 3-2 shift point P32, the first sync D1 needs to be moved from the third speed side to the first speed side and completed. For this reason, the 3-2 shift point P32 must be set before the 2-1 shift point P21 by the time the first sync D1 moves.
[0075]
In other words, the rotational speed that changes during the time that the first synchro D1 moves (from the third speed to the first speed) is ΔNOS2, and the synchronous speed of the fourth speed at the 2-1 shift point P21 is changed to this. Let P2 be the point where ΔNOS2 is added. This point P2 is considered as the first candidate for the shift point P32 from the third speed to the second speed.
[0076]
On the other hand, if the point on the fourth rotational speed DK4 at the time t9 at which the synchronous rotational speed DK3 at the third speed and the target rotational speed NTt intersect is P3, the third speed clutch cl3 at this point P3. Since the duty ratio of the (first clutch C1) becomes 0%, the first quick fill of the second speed clutch cl2 (second clutch C2) before the point P3 is the same as when the shift point P21 is determined. And the second speed clutch cl2 must be able to have a capacity. In other words, the 3-2 shift point P32 is a point obtained by adding the rotational speed ΔNOF2 that changes in the time required for the capacity of the second speed clutch cl3 (second clutch C2) to the fourth speed synchronous rotation speed at the point P3. Must be set to P4 (previous) (second candidate point).
[0077]
  As a result, the 3-2 shift point P32 is a point.P2And two points of time point P4 are considered as candidates, but the shift point P32 must satisfy both of the above-mentioned conditions. Therefore, the point P4 on the side closer to the current vehicle speed (high vehicle speed side) is determined as the 3-2 shift point P32.
[0078]
The 4-3 shift point P43 from the fourth speed to the third speed is determined in exactly the same manner.
[0079]
From the 3-2 shift point P32 as a reference, the second synchro D2 moves from the 4th speed to the 2nd speed until the rotation speed DK4 of the 4th speed at the 3-2 shift point P32. A point in time at which the rotational speed ΔNOS3 changing with time is added is defined as a point P5 (time t3).
[0080]
Also, the time t4 at which the synchronous rotational speed DK4 of the fourth speed and the target rotational speed NTt intersect is set as the point P6, and the third speed clutch cl3 (second clutch C1) performs the first quick fill from the point P6. Let P7 (time t2) be a point obtained by adding the rotational speed .DELTA.NOF3, which changes during the time when the capacity can be obtained, to the rotational speed DK4 of the fourth speed at the time point P6.
[0081]
In the same manner as described above, the point P7, which is the point closer to the current vehicle speed side (high vehicle speed side) among the points P6 and P7, is set as the 4-3 shift point P43 from the fourth speed to the third speed. .
[0082]
Next, as shown in FIG. 2, how to determine the shift point when the vehicle is suddenly decelerated will be described.
[0083]
Compared to FIG. 1, the time t'17 is determined closer to the present time (left side of the figure), but the same as in FIG. For this reason, the movement periods of the synchronization mechanisms D1 and D2 are displayed relatively long.
[0084]
Even in the case of sudden deceleration just like the slow deceleration, first, the 2-1 shift point P'21 is determined, and the 3-2 shift point P'32 is determined based on that, and finally the 3-2 shift point P'32 is determined. 4-3 shift point P'43 is determined based on the above.
[0085]
A description will be given from the determination of the 2-1 shift point P′21 for performing the shift from the second speed to the first speed.
[0086]
A point on the synchronous rotational speed DK4 of the fourth speed stage at a point where the synchronous rotational speed DK2 of the second shift stage and the target rotational speed NTt intersect is defined as P'0. The time t′10 of P′0 is the time when the duty ratio of the second speed clutch cl2 is set to 0% (drain), and is also the time when the first speed clutch cl1 starts the feedback control. Accordingly, as in the case of slow deceleration, the 2-1 shift point P'21 must be ahead of the point P'0 by the amount of time that can have capacity after the first quick fill. That is, the point P′1 (time t′9) obtained by adding the rotational speed ΔNOF′1 that changes during the time that the first speed clutch cl1 can have capacity to the synchronous rotational speed of the fourth speed at the time of P′0. ) Is defined as 2-1 shift point P'21.
[0087]
Next, since the 3rd to 2nd shift point P'32 from the 3rd speed to the 2nd speed must naturally complete the movement of the 1st synchro D1 from the 3rd speed to the 1st speed. P'2, which is a point obtained by adding a rotational speed ΔNOS'2 that changes during the time required for the first sync D1 to move, is added to the turbine rotational speed at the shift point P'21.
[0088]
Also, the point on the synchronous rotational speed DK4 of the fourth speed at the time t'8 when the synchronous rotational speed DK3 of the third speed intersects the target rotational speed NTt is P'3, and the fourth speed of the point P'3 is P'3. A point obtained by adding a rotational speed ΔNOF′2 that changes during the time that the third speed clutch cl3 performs the first quick fill and can have the capacity to the synchronous rotational speed DK4 of the stage is defined as P′4.
[0089]
Here, the point P'2 closer to the current vehicle speed among the points P'2 and P'4 is set as the shift point P'32 from the third speed to the second speed.
[0090]
The 4-3 shift point P43 at the time of sudden deceleration is determined by the same method.
[0091]
That is, the shift point is determined by the time based on the first quick fill (time) in many cases during slow deceleration (all in the embodiment in FIG. 1), but in many cases (in the embodiment in FIG. 2) during sudden deceleration. In all cases, the shift point is determined based on the movement (time) of the synchro. In either case, that is, when the shift point is determined depending on the time of the first quick fill, etc., or when the shift point is determined depending on the movement of the synchro, after all, it depends on the deceleration. It will be required.
[0092]
In addition, since the shift point is determined according to the deceleration for both slow deceleration and sudden deceleration, if the deceleration changes even after the shift point has been determined once, the next shift point is corrected accordingly accordingly. And changed.
[0093]
Further, the shift point obtained in this way is used after being specifically added to the value of the output shaft rotation speed as will be described later.
[0094]
Next, the control flow in this embodiment will be described in detail.
[0095]
FIG. 5 is a flowchart of the overall shift control, FIG. 6 is a shift control subroutine flowchart, FIG. 7 is a synchro control subroutine flowchart, and FIG. 8 is a coast down point calculation subroutine flowchart. Since the substantive contents have already been described with reference to FIGS. 1 and 2, the procedure will be briefly described along the flowcharts.
[0096]
As shown in FIG. 5, this series of control flow mainly includes a shift control process routine (step 001) and a coast down control process routine (step 002). The coast down control processing routine (step 002) has already been described in detail prior to the change of the shift point, and is outside the scope of the present invention. Therefore, the description of the specific control flow is omitted here. The shift control routine (step 001) among these will be described in detail with reference to FIGS.
[0097]
In step 101, the current shift determination is stored in msftjdg, and in step 102, an upshift shift point and a downshift shift point are map-searched based on the shift position, shift determination stage, and accelerator opening. Here, the shift determination stage indicates a shift stage that is obtained as a result of determining the current driving condition or what speed stage should be present from the driving state. The shift position means the position of the shift lever such as the drive range, the second speed range, or the reverse range, and the upshift shift point and the downshift shift point are determined in advance by a map on the up side and the down side at that point. It is the shift threshold value of the output shaft rotation speed.
[0098]
If it is determined in step 103 that the coast downshift condition is satisfied, a coast down shift point is calculated as described with reference to FIGS. 1 and 2 (see FIG. 8: described later). In step 104, it is determined whether or not the output shaft rotational speed is higher than the upshift speed point. If it is determined that the output shaft speed is high, the shift determination stage is incremented by 1 in step 105, the up flag is turned on, and the down flag is turned off. Execute upshift judgment. On the other hand, if the output shaft rotational speed is equal to or lower than the upshift speed change point at step 104, downshift determination is similarly performed at steps 106 and 107.
[0099]
In step 108, it is determined whether or not the shift determination stage has been changed. If the shift has been performed, the process returns to step 101 to update the shift determination based on the new shift determination stage. If not changed in step 108, the process proceeds to step 109 to perform a sync control process (described in FIG. 7 described later).
[0100]
Steps 110 to 115 are for controlling the reflection of the shift output of the shift determination stage when the shift prohibition flag is off (step 110). With this control flow, even when the downshift from the fourth speed to the third speed is determined, the fourth speed → the third speed at time t2, the third speed → the second speed at time t7. At time t12, the procedure for sequentially generating the shift output from the second speed to the first speed is realized.
[0101]
Next, FIG. 7 shows a subroutine of the synchro control process executed in step 109 (FIG. 6).
[0102]
In step 201, a map search is performed for the synchro position determination (where the synchro mechanism should finally be) from the shift position, the shift determination stage, and the output shaft rotation speed. In step 202, it is determined whether or not the sync position determination obtained as a result is different from the actual sync position output. If they are different, the sync movement request flag is turned on and the sync movement completion flag is turned off in step 203. .
[0103]
FIG. 4B shows an example of a sync position determination map in the D range. For example, when the shift determination stage is the first speed stage, the output shaft rotation speed at that time is divided into cases when it is lower than No1 and when it is higher, and when the output shaft rotation speed is lower than No1, the first speed is set. In addition to the position, a neutral position is prepared in advance. When the output shaft rotation speed is greater than No. 1, the sync position is selected and connected in advance to the first speed side and the second speed position. This is because when the output shaft rotation speed is higher than No1, there is a high possibility that the next shift is a shift to the second speed. Similarly, when the shift determination stage is the second speed stage, if the output shaft rotation speed at that time is smaller than No2, the first position and the second speed position are selected for the synchro position determination, and the output shaft rotation speed is No2. When it is larger, the 2nd speed position and the 3rd speed position are determined as “sync position determination”.
[0104]
In steps 204 to 209, the operation of switching the second sync D2 position from the 4th speed position to the 2nd speed position in the slow deceleration of FIG. 1 is started from time t5 and finished at time t6, and the position of the first sync D1 is set to 3. This operation corresponds to an operation performed when it is confirmed that the operation for switching from the speed position to the first speed position starts at time t10 and is completed at time t11.
[0105]
That is, if the synchronization movement is in progress (step 204), or if the synchronization movement prohibition club is on (step 205) and the synchronization movement request flag is on (step 206), the synchronization movement is executed (step 207). Determine completion of synchro movement. If the movement is completed, the synchronization movement completion flag is turned on and the movement flag is turned off in step 204, and the synchronization position determination is substituted for the synchronization position output.
[0106]
Next, FIG. 8 shows a schematic flow of the coast down shift point calculation subroutine executed in step 103 (FIG. 6).
[0107]
In FIG. 8, it is determined in step 301 whether or not a coast down precondition is satisfied. In this embodiment, the prerequisites for the coast down are the following conditions.
[0108]
1. D range selection
2. Idle contact ON
3. The accelerator opening is less than a predetermined value close to zero.
4). Output shaft rotation speed More than a predetermined value corresponding to the time t16 (t'16)
[0109]
If the above conditions are not satisfied, the process goes to the return step and the control is terminated.
[0110]
If the precondition is satisfied, the shift point NOF considering the time required for the first quick fill and the shift point NOS considering the synchro movement time are set to 0 in step 302, and i indicating the shift stage at the time of calculation is 2 And This is to set the shift point P21 for shifting from the second speed to the first speed. When performing the shift from the third speed to the second speed, i = 3, When shifting from the fourth speed to the third speed, i = 4.
[0111]
  At step 303, the first quick fill with the vehicle deceleration as a parameter + the rotational speed ΔNOF that changes for β time and the rotational speed ΔNOS that changes for the synchronized movement time are mapped.TheSearch. Here, not the map search, the vehicleDecelerationYou may calculate directly from
[0112]
As described above, β corresponds to the time until the corresponding clutch can have a marginal capacity after the end of the first quick fill.
[0113]
In step 304, it is determined whether i = 2. Since the initial value is 2, in step 306, the coast down shift point NOS considering the synchro movement time is set to zero. Next, in step 307, in order to calculate the coast down shift point NOF considering the first quick fill time, the following calculation is performed. That is, the feedback target rotational speed NTt (= engine rotational speed + predetermined value α) is divided by the gear ratio of the gear stage indicated by i (initially the second gear ratio), and the synchronous rotational speed at the gear stage indicated by i and the target The output shaft rotational speed that makes the rotational speeds equal is calculated, and ΔNOF that has been subjected to map search in step 303 is added to that value.
[0114]
In steps 308 to 310, the greater of NOS and NOF (higher vehicle speed side) is substituted from the shift stage i to the shift stage (i-1) into the NOC at the shift point for coasting down. In step 311, 1 is added to i, and in step 312, it is determined whether i is equal to or smaller than the current gear, and if it is equal to or smaller than the current gear, the process returns to step 303 and i becomes larger than the current gear. Steps 303 to 312 are repeatedly performed until the above. Here, since i is not 2 after the second time, the process proceeds from step 304 to step 305, and NOC + ΔNOS is substituted for NOS. If i becomes larger than the current shift speed in step 312, NOC is substituted in step 313 for the down point used in the determination in step 106 of FIG.
[0115]
As described above, since the shift is performed in the range of the low speed stage side synchronous rotational speed> feedback target rotational speed NTt, the turbine rotational speed NT can always be fed back to the target rotational speed, and a predetermined engine brake is always applied. Can be generated.
[0116]
When the present invention is applied to an automatic transmission that does not have a synchro mechanism, it is naturally not necessary to consider the movement time of the synchro mechanism in determining the shift point.
[0117]
【The invention's effect】
  As explained above, this bookAccording to claim 1According to the invention,Means for determining a time required for the synchro mechanism to move when downshifting during the coast; means for determining a time required for the first quick fill; a shift point based on the time required for the synchro; and the first quick A shift point based on the time required for the fill, and means for selecting a shift point on the high vehicle speed side among the shift points, and downshifting during the course according to the selected shift point,Since there is no need to set the shift point higher than necessary, excessive engine braking during deceleration is suppressed, shift shock is always suppressed at any deceleration, and a good downshift can be executed. An excellent effect is obtained.
[Brief description of the drawings]
FIG. 1 is a time chart showing how to change and set a shift point by slow deceleration according to the present invention.
FIG. 2 is a time chart showing how to change and set a shift point by sudden deceleration according to the present invention.
FIG. 3 is a block diagram showing an outline of an automatic transmission for a vehicle to which the present invention is applied.
FIG. 4 is a diagram showing an engagement state of each friction engagement device and a switching state of a synchro mechanism of the automatic transmission.
FIG. 5 is a flowchart showing control processed in a computer to perform a coast downshift in the automatic transmission.
6 is a flowchart showing a shift control processing subroutine in FIG. 5;
FIG. 7 is a flowchart showing a synchro control processing subroutine in FIG. 5;
FIG. 8 is a flowchart showing a coast down shift point calculation subroutine in FIG. 5;
[Explanation of symbols]
C1 ... 1st clutch
C2 ... Second clutch
NT: Turbine rotation speed
NTt ... Feedback target rotation speed
30 ... Computer
40. Various sensor groups
NE ... Engine speed
DK1 to DK4 ... Synchronous rotation speed of each gear stage
ΔNOF: Rotational speed that changes during the first quick fill time
ΔNOS: Rotational speed that changes in synchro travel time

Claims (2)

  1. An automatic transmission having a plurality of clutches and a plurality of synchronization mechanisms and performing a clutch-to-clutch shift that performs a downshift according to a shift point during coasting, and is completely applied to a clutch to be engaged at the initial stage of the clutch-to-clutch shift. In a shift control device for an automatic transmission that performs a first quick fill that applies a hydraulic pressure supply command for a predetermined time,
    Means for obtaining a time for the synchro mechanism to move when downshifting during the coast;
    Means for determining the time required for the first quick fill;
    Means for selecting a shift point on the high vehicle speed side from among a shift point based on a time required for the synchro to move and a shift point based on a time required for the first quick fill;
    Shift control device for an automatic transmission, characterized in that a downshift is performed during the coasting accordance the selected shift point.
  2. Means for detecting vehicle deceleration,
    The shift control device for an automatic transmission according to claim 1, wherein a shift point based on a time required for the synchro movement and a shift point based on a time required for the first quick fill are changed in accordance with a deceleration of the vehicle. .
JP06105798A 1998-03-12 1998-03-12 Shift control device for automatic transmission Expired - Fee Related JP3951419B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
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Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP06105798A JP3951419B2 (en) 1998-03-12 1998-03-12 Shift control device for automatic transmission

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JP3951419B2 true JP3951419B2 (en) 2007-08-01

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Publication number Priority date Publication date Assignee Title
JP4515564B2 (en) * 1999-11-08 2010-08-04 アイシン・エーアイ株式会社 Shift automatic return device in automatic transmission
US6740005B2 (en) * 2001-08-01 2004-05-25 Toyota Jidosha Kabushiki Kaisha Shift control apparatus of automatic transmission of motor vehicle
JP4400639B2 (en) 2007-03-14 2010-01-20 トヨタ自動車株式会社 Hydraulic control device for automatic transmission
JP5434743B2 (en) 2010-03-29 2014-03-05 アイシン・エィ・ダブリュ株式会社 Shift control device and transmission device

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