JPH01105046A - Speed change control device for automatic transmission - Google Patents

Abstract

PURPOSE:To promote the improvement of accelerating and driving quality while suppressing a slip and ensuring a starting quality by performing high speed shift starting with an output of a low mu output means on a low mu road and a shift down by one speed shift after the starting. CONSTITUTION:A control unit 20 inputs each signal of a range position sensor 5, throttle opening sensor 6, car speed sensor 7, driven wheel speed sensor 8a and a drive wheel speed sensor 8b, and when a low mu road is decided by a speed difference between a driven wheel and a drive wheel, the control unit 20 corrects a speed change shift in an automatic transmission 2 from a normal starting of 1-speed or 2-speed to a high speed side of 4-speed, suppressing a slip of the drive wheel to perform starting. Next performing the starting, when a car speed increases to, for instance, 20Km/H or more, the speed change shift is corrected by shift down to 3-speed. Thus while ensuring a starting quality in the low mu road, the improvement of accelerating and driving quality after the starting can be promoted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a shift control device for an automatic transmission.

[Prior art]

BACKGROUND ART Conventionally, many vehicles equipped with automatic transmissions have been put into practical use that are equipped with a shift control device that automatically performs all shift control of a plurality of gears associated with starting, running, and stopping.

In such an automatic transmission, there is generally a shift control bag W (hereinafter referred to as a normal shift control device) that automatically controls the shift within a shift range preset in the shift control device in accordance with the range position of the manually operated shift lever. ) is used. To explain with a specific example, the range positions for forward travel are 'rDJ (drive), 'S',
There are three types of rLJ, and in the rDJ range, automatic gear shifting is performed in the range of 1st to 4th gears, which are all gears, and rsJ
In the range, automatic shifting is performed in the range of 1st to 3rd speeds, and furthermore, in the rLJ range, automatic shifting is performed in the range of 1st and 2nd speeds.

By the way, recently, even in the above-mentioned normal shift control device, there is a system that controls the gear so that a manual shift feeling can be obtained, that is, a specific gear is associated with each range position, and each range position of the shift lever is controlled to correspond to that gear. There is a speed change control device (hereinafter referred to as a manual speed change control device) that performs control to maintain the speed. For example, in the above example, the rDJ range is set to 3rd gear, the "S" range is set to 2nd gear, and the rLJ range is set to 1st gear, and the shift lever is manually operated to change the range position, thereby allowing manual gear shifting. A manual speed change control device has been proposed that allows this.

The gear position when the vehicle starts in the forward driving range position is 1st speed in the normal transmission control device, and is also set to 2nd speed in the rDJ range position in the manual transmission control device. (This is so that it can be set to 2nd gear only when starting, taking into consideration the starting acceleration.)

As described above, in the conventional automatic transmission shift control device, the shift stage is normally set to 1 consecutive gear or 2nd gear when the vehicle starts.
In the automatic transmission shift control device described in Publication No. 8,
Parked and in a slot.

When the torque opening is zero, that is, when the shift lever is in the idling state, the shift lever is set to "N".
There is a control system that temporarily sets the gear position to 2nd or 3rd gear when the shift lever is operated from the rNJ range position to the rDJ range position. 1. The torque fluctuation during engagement is the largest among the gear ratios. The purpose is to reduce the above-mentioned engagement shock by engaging a second or third gear with a small gear ratio, so as not to cause an unpleasant engagement shock that is increased by a higher gear ratio. When the throttle is depressed (when starting the vehicle), the gear is switched from 2nd or 3rd gear to 1st gear and returns to normal gear shift control.

That is, in the conventional shift control device for an automatic transmission, the gear position at the time of starting is controlled to be set to 1st speed or 2nd speed.

[Problem that the invention seeks to solve]

Incidentally, from the viewpoint of acceleration performance of the vehicle when starting, it is desirable to transmit a large drive torque to the drive wheels of the vehicle at the time of starting, and it is also efficient in terms of acceleration after starting.

However, when starting on a low μ road, for example when starting from a snowy road, ice burn, mixed road, sandy road, etc. where the friction between the drive wheels and the road surface is low, large drive torque may be inadvertently transmitted to the drive wheels. , there is a problem that the drive wheels spin (slip), making it impossible to start.

Therefore, in such cases, in vehicles with so-called manual transmissions that do not use automatic transmissions, the shift lever
is arbitrarily operated to shift to a gear position that generates a low driving torque, that is, a high-speed 3rd or 4th gear position, thereby transmitting a small driving torque to the drive wheels to prevent the drive wheels from spinning and start the vehicle. However, in vehicles with automatic transmissions that are automatically controlled by conventional transmission control devices,
Since the gear position at the time of starting is automatically set to the first gear or second gear which generates a high driving torque, there is a problem that the vehicle cannot start.

Accordingly, an object of the present invention is to provide a shift control device for an automatic transmission that can improve the starting performance of a vehicle on a low μ road and the practical running performance after starting.

[Means for solving problems]

A shift control device for an automatic transmission according to the present invention is a shift control device for an automatic transmission that sets the gear stage of the automatic transmission to 1st or 2nd speed when starting a vehicle in a drive range, and is provided with A low μ output means outputs a signal when the condition is recognized, and a starting supplementary device receives the output of the low μ output means and sets a gear position at the time of starting the vehicle to a high speed gear of 3rd speed or higher. It is something.

[Operation] In the shift control device for an automatic transmission according to the present invention, during normal start-up when the friction between the road surface and the drive wheels is sufficiently large, the shift control device sets the gear stage of the automatic transmission to 1st or 2nd speed. Therefore, a sufficiently large driving torque is transmitted to the driving wheels, resulting in excellent starting acceleration. On the other hand, when the friction between the road surface and the driving wheels is small, that is, when it is understood that the state is low,
In response to the output of the output means, the start correction means changes the gear position of the automatic transmission to a high speed gear of 3rd gear or higher (low drive torque generation side gear)
This setting prevents the drive wheels from spinning and allows a stable start, and after the start, the travel correction means shifts down the automatic transmission by at least one gear from the gear set at the time of start, so the speed is quickly achieved. The drive torque can be increased over time (eliminating the feeling of sluggishness during acceleration), and the practical driving performance (acceleration performance) after starting is also improved.

〔Effect of the invention〕

According to the shift control device for an automatic transmission according to the present invention, as explained above, when starting on a low μ road, slip is suppressed by starting at a high speed gear with low drive torque to ensure starting performance, and after starting, the starting performance is ensured. (By shifting down to the first gear, the driving torque can be increased and acceleration and drivability can be improved.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

First, the overall outline of a shift control device 1 for an automatic transmission will be explained with reference to FIG. A known transmission 2 equipped with a planetary gear mechanism is connected to an engine output shaft via a torque converter, and switches its power transmission path by appropriately operating a friction element such as a clutch or brake attached to the transmission. In other words, a gear change is performed. The hydraulic pressure supply mode to the actuator for operating the friction element is switched by a hydraulic control circuit HC, and the hydraulic pressure supply control by the hydraulic control circuit HC is performed by a plurality of solenoids S.
This is done by a combination of excitation and demagnetization of the OL (a solenoid pattern).

A control unit 20 is provided which controls the speed change of the transmission 2 by controlling the solenoid SQL, and the control unit 20 has two mode switches (selection of two speed change characteristic modes consisting of a POWER mode and an ECONOMY mode). Changeover operation switch (
Hereinafter referred to as P/E mode switch) 3 and HO (described later)
In addition to each signal input to the selection changeover operation switch (hereinafter referred to as HOLD mode switch) 4 that cancels the LD mode setting, five sensors (range position sensor 5, throttle opening sensor 6, vehicle speed sensor 7, and driven wheel Signals from a rotational speed sensor 8a and a driving wheel rotational speed sensor 8b) are input. Further, the control unit 20 outputs a solenoid pattern signal to the solenoid SQL, and also outputs lighting/unlighting signals to the three display lamps 11, 12, and 13.

The range position sensor 5 detects the range position described later, the throttle opening sensor 6 detects the opening of the engine throttle valve, and the vehicle speed sensor 7
is for detecting the running speed of the vehicle, and the driven wheel rotation speed sensor 8a and the drive shaft rotation speed sensor 8b are for detecting the rotation speeds of the driven wheels and the driving wheels, respectively.

The control unit 20 includes each of the switches 3 and 3.
4 and each sensor 5 to 8b and individually converts the signal into a digital signal;
It is equipped with a microcomputer consisting of U, CLOCK, ROM, and RAM, an output interface, and a drive circuit for outputting a solenoid pattern signal to the solenoid SQL mentioned above.
Control programs for the start correction control (start correction means) and running correction control (driving correction means), control programs necessary for normal shift control, and various memory maps (shift control characteristics in the three shift modes described later, i.e., throttle opening signal and vehicle speed) A memory map, etc. that defines four gear ranges based on signals, shift amplifiers, and downshift timings, etc.) are input and stored in advance. The RAM is also provided with various memories (buffer memory, flag memory, counter memory, etc.) necessary to execute each of the above-mentioned controls.

Next, as shown in FIGS. 2 and 3, the P/E mode switch 3, the HOLD mode switch 4, and the display lamp 1 are
Specific examples 1 to 13 will be explained.

rPJ, rRJ, rN by manually moving the shift lever 14 installed in the driver's seat back and forth.
Each range position of J, rDJ, rSJ, and rLJ can be arbitrarily selected.

As is known, the above rPJ, rRJ, and rNJ indicate "parking", "reverse", and "neutral", and rDJ, "S", and rLJ are the range positions of the forward gear, Since the transmission 2 has 4 forward speeds with overdrive, when the HOLD mode is not set (hereinafter referred to as automatic shift mode), the rDJ operates in the range of 1st to 4th gears. automatic shifting is selected, and in RSJ, automatic shifting is available in the range of 1st to 3rd speeds.
' speed selection, and in rLJ, automatic shift selection between 1st speed and 2nd speed. Also, the above rDJ, “S”, rLJ
When the HOLD shift is set (hereinafter referred to as HOLD shift mode), each range position is "D" to hold 3rd gear (fixed), and rsJ to hold 2nd gear (fixed).
(fixed), and "L" holds 1st speed (fixed). The lunge position display section 15 provided on the side of the shift lever 14 displays the rPJ, rRJ, rNJ, rDJ, rS
J, rLJ, and the possible gears "3", "2", and "1" in the HOLD shift mode are displayed, and the current range position (hold The gear position to be changed) is displayed on the first lunge position display section 15.

A HOLD mode switch 4 for switching between the HOLD shift mode and the automatic shift mode is attached to the side surface of the operating portion of the shift lever 14, and in this embodiment, it is a momentary type switch. Therefore, when the HOLD mode switch 4 is pressed once when it is not currently in the HOLD shifting mode, it means that the HOLD shifting mode is selected, and when it is pressed once when it is currently in the HOLD shifting mode, the HOLD shifting mode is canceled. In addition, a P/E mode switch 3 for shifting control characteristic selection is provided at a position directly in front of the shift lever 14, and in this embodiment, it is an alternate switch. . Therefore, for example, when the P/E mode switch 3 is pushed in, the ECONOMY mode is selected, and when it is pressed again from this state, the POWER mode is selected, which returns to its original position.

On the other hand, as shown in FIG. 3, the meter panel 16 is provided with a speedometer 1, 7, a tachometer 18, a second range position display section 19, and the three lamps 11, 12, and 13. . The second range position display section 19 is designed to display the current range position using a pointer 19a that is linked to the shift lever 14. Unlike the HOLD shift mode, the shift mode is held during the shift mode.
3", "2", and "1" are not displayed.

The P/E mode switch 3 is used to manually select two different shift control characteristics shown in FIG. 4 in the automatic shift mode. That is, in the embodiment, two types are set in advance in the ROM of the control unit 20: a POWER mode that emphasizes driving performance such as acceleration, and an ECONOMY mode that emphasizes economy such as fuel consumption, and the P/E mode switch 3 This operation switches between the POWER mode and the ECONOMY mode. In these two shift control characteristics, the timing of upshifting and downshifting is determined by using the throttle opening and vehicle speed signals as parameters.
R mode is set so that the vehicle speed is higher than ECONOMY mode, so that it can always drive powerfully (large drive torque).

Further, the HOLD mode switch 4 can be manually operated to associate a specific gear position with each range position for forward travel as described above, and manually operate the shift lever 14 to change the range position. This allows manual gear shifting, and in this embodiment, as shown in Figure 4, the gear is fixed at 3rd gear at the rDJ range position.
In the "S" range position, it is fixed at 2nd speed, and in the rLJ range, it is controlled to be fixed at 1st speed.

In the display lamps 11 to 13, the lamp 11 lights up to indicate that the POWER mode is selected, and the lamp 12 lights up to indicate that the ECONOMY mode is selected. The lamp 13 lights up to indicate that the HOLD shift mode is selected.

On the other hand, the transmission 2, the hydraulic control circuit HC, and the solenoid SQL have the same structure and mechanism as those conventionally known, so a description thereof will be omitted.

Next, the control contents of the automatic transmission shift control device 1 configured as above will be explained below.

First, the control contents of the control unit 20 in normal speed change control (normal control other than the low μ state that is the object of the present invention, hereinafter referred to as normal control) will be briefly described.

When the automatic shift mode is selected, that is, when the HOLD mode switch 4 is in a state to cancel the HOLD shift mode, the range position signal from the range position sensor 5 (currently selected range position) is Within the determined gear range, a preset solenoid pattern signal is output to solenoid SQL to perform automatic shift control based on each shift control characteristic. In this case, the shift control characteristic is P/E mode. PO selected by switch 3
This is done according to WER mode or ECONOMY mode. That is, at the time of starting, a continuous solenoid pattern signal is output to the solenoid SQL to set the gear position of the transmission 2 to 1st speed and start, and after starting, each signal from the throttle opening sensor 6 and vehicle speed sensor 7 is output. In response to this, a solenoid pattern signal corresponding to each gear (1st to 4th speed) is output in the four gear ranges based on the gear shift control characteristics, and the shift up and down shift are performed as appropriate from running to stopping. It is meant to be controlled. In this automatic shift mode, when the POWER mode is selected as the shift control characteristic, only the lamp 11 is lit up and the remaining lamps 12 and 13 are turned off. Furthermore, when the ECONOMY mode is selected as the speed change control characteristic, only the lamp 12 is lit up and the remaining lamps 11 and 13 are turned off.

On the other hand, when the driver selects the HOLD shift mode, that is, when the HOLD shift mode is set by operating the HOLD mode switch 4, a specific gear position corresponding to the currently selected range position (see Fig. 4) is selected. is held fixed. Then, by manually moving the shift lever 14 to change the range position, for example from 3rd gear to 2nd gear (when the shift lever 14 is operated from the "D" range position to the "S" range position). The gear is shifted to. Also, when starting in HOLD shift mode, "L"
Control is performed to start by outputting a solenoid pattern signal for 1 speed in the range position and 2nd speed in the rSJ range position, but in the rDJ range, a fixed gear position (3rd speed) is output in consideration of starting acceleration. ) is designed to output a solenoid pattern signal for 2nd speed, which is one speed lower than 2nd speed. Therefore, the gear position at the time of normal start in the HOLD shift mode is set to 1st or 2nd gear. Also, when this HOLD shift mode is selected, lamps 11 and 12 are displayed to indicate the type of shift control characteristics.
are both turned off, and only the lamp 13 indicating that the HOLD shift mode is selected is lit. Note that the lamps 11 and 12 are turned off regardless of whether the P/E mode switch 3 selects the POWER mode or the ECONOMY mode.

Here, since the control program of the control unit 20 in the normal control explained above is conventionally known, a detailed explanation of this control will be omitted. The start correction control and running correction control when it is recognized that the condition is present will be explained below based on the flowchart shown in FIG.

In the figure, 81 to S9 indicate each step, and when the ignition switch (the path shown) is turned on, the normal control (the path shown in the flowchart) and the start correction/travel correction control are started. In step 3.1, the range position signal from the digital position sensor 5 is read, it is determined whether the rDJ range is selected by the shift lever 14, and the rDJ range is selected by the shift lever 14.
Ranges other than J range (i.e. “S” range or rLJ
range), the process moves to S9 and normal control at the selected range position is performed, and in the case of the rDJ range, the process moves to S2.
to move to.

In S2, the vehicle speed signal from the vehicle speed sensor 7 is read, and it is determined whether the vehicle speed is zero (i.e., whether the vehicle is stopped or not), and if the vehicle speed is not zero (i.e., if the vehicle is running).
moves to S8 and normal control at the rDJ range position is performed, and when the vehicle speed is zero (that is, when stopped), S
Move to 3. At this time, the solenoid pattern signal of the starting gear position (1st or 2nd gear) in normal control is output to the solenoid SQL, and the gear position of the diamond transmission 2 is set to 1st gear or 2nd gear.

In S3, the rotational speed signal P from the driven wheel rotational speed sensor 8a and the rotational speed signal Pb from the driving wheel rotational speed sensor 8b are respectively read, and it is determined whether Pb>P (that is, whether the driving wheel is idling). p b 5
In the case of P (not idling), the process moves to S8 and normal control at the rDJ range position is performed. If P h > p m (idling state), the process moves to S4.

In S4, a 4th speed solenoid pattern signal is outputted to the solenoid SQL again, and the starting speed (1st or 2nd speed) initially set based on normal control is corrected to 4th speed. In other words, when the drive wheels are in a slip state, the gear of the transmission 2 is corrected to 4th gear, which is the high speed gear (low torque transmission gear), and the drive wheel is started while suppressing the slip. It is. Next, the process moves to step 85, where it is determined whether the vehicle speed signal is equal to or higher than 201 ua/h. If the speed does not reach 20km/h, return to s4,
36 when the vehicle speed reaches 20 km/h or more while maintaining 4th gear.
to move to.

In S6, a solenoid pattern signal for 3rd gear, which is one gear lower than the corrected gear at the start, is output to solenoid SQL, and the gear of the transmission 2 is corrected to 3rd gear. In other words, this is to prevent slippage after a stable start so as not to impede practical driving performance in terms of acceleration and response to throttle opening, and to prevent sudden torque fluctuations from being transmitted to the drive wheels. Therefore, the drive torque is increased by correcting the gear position to be one gear lower than the corrected gear position at the time of starting. Next, the process moves to 87, where it is determined whether the vehicle speed signal is not zero (that is, whether the vehicle is running or not). If the vehicle is running), the process moves to S8 and the subsequent control is r.
The control is returned to normal control at the DJ range position.

Therefore, according to the automatic transmission shift control device 1 of the present embodiment, if normal control is performed at the rDJ range position, when starting on a low μ road such as a snowy road, ice burn, mixed road, or sandy road, the drive When the wheels are in a slip state, inadvertently transmitting a large drive torque to the drive wheels and being unable to start the vehicle is automatically prevented.

Needless to say, when starting on a low μ road, if it is determined that it is better to start in the low gear of 1st or 2nd gear depending on the situation, the "s It is also possible to start the vehicle in 1st or 2nd gear by operating the shift lever 14 to the range position.

In addition, in the flowchart of the start correction/running correction control shown in FIG. 5 of this embodiment, the set vehicle speed at s5 is set to 2.
0 km/h, but if the vehicle speed is set appropriately, it will be 20 km/h.
S5 is not limited to km/h, and S5 may be determined using a timer counter that has been set for a predetermined time. Furthermore, S5 may be determined based on the relative relationship between the throttle opening signal and the vehicle speed; It may be determined based on the acceleration request, and the solenoid S in s4
Output the 3rd speed solenoid pattern signal to QL, and
6, the second speed solenoid pattern signal may be output.

Furthermore, as a modified example, as shown in FIGS. 6 to 8, the driven wheel rotation speed sensor 8a and the driving wheel rotation speed sensor 8b are omitted, and a 5NOW switch 8A consisting of a manual operation switch is placed on the front right side of the shift lever 14. Further, the lamp 21 may be provided at the right position of the lamp 13 in the meter panel 16. That is, the signal from the 5NOW switch 8A is output in the control unit 20, and when the 5NOW switch 8A is turned ON, the lamp 21 is displayed as being lit, and when it is turned OFF, the lamp 21 is turned off. S3 in the control flowchart (Fig. 5) is replaced with S3' shown in Fig. 9, and when the 5NOW switch 8A is in the ON state, 84
Control may be performed so that the subsequent start correction (S4) and running correction (S6) are performed. That is, when starting on a low-μ road such as a snowy road, the driver manually operates the 5NOW switch 8A to perform start correction and running correction control, which also enables reliable start. Furthermore, of course, the above-mentioned driven wheel rotation speed sensor 8a and driving wheel rotation speed sensor 8b,! :5
It is also possible to use a mechanism in which the NOW switch 8A is installed in parallel to automatically or manually control the start correction and running correction.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a general schematic diagram of a shift control device for an automatic transmission, and FIG. 2 shows the arrangement of a shift lever, a P/E mode switch, and a HOLD mode switch. A perspective view of the main parts, Fig. 3 is a front view showing the arrangement of lamps indicating the type of shift control characteristics and lamps indicating that HOLD mode is selected, and Fig. 4 shows shift control in each mode in normal shift control. Explanatory diagram showing the fifth
The figure is a flowchart showing a control routine for start correction/travel correction control, and FIGS. 6 to 9 are views corresponding to FIGS. 2, 3, 1, and 9, respectively, according to modified examples. 5... Range position sensor, 6... Throttle opening sensor, 7... Vehicle speed sensor, 8a... Driven wheel rotation speed sensor, 8b... Driving wheel rotation speed sensor, 8A... 5NOW
Switch, 20...Control unit. Figure 1 Figure 2 Figure 4 Figure 6 Figure 9

Claims (1)

[Scope of Claims] 1) In a shift control device for an automatic transmission that sets the gear stage of the automatic transmission to 1st or 2nd gear when starting a vehicle in a drive range, it is determined that a low μ state exists between the road surface and the wheels. a low μ output means that outputs a signal when the vehicle is started; a start correction means that receives the output of the low μ output means and sets the gear position at the time of starting the vehicle to a high speed gear of 3rd gear or higher; 1. A shift control device for an automatic transmission, comprising a travel correction means for downshifting at least one gear after starting the gear.