JPH04254063A - Control device for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent engine brake feeling from being spoiled by restricting the change of a speed change pattern into a high oil temperature pattern in the state of engine load being less than the specified value at the hold mode travel time. CONSTITUTION:On the basis of input information such as vehicle speed and engine load, a speed change control means outputs a speed change control signal to a speed change control circuit according to a speed change pattern to perform the speed change control of an automatic transmission. When the oil temperature of the automatic transmission becomes the specified high temperature, the speed change pattern is changed into a high oil temperature pattern by a speed change pattern changing means so as to enlarge a low speed stage region. When engine load is less than the specified value at the hold mode travel time, however, the change into the high oil temperature pattern is restricted by a high oil temperature pattern restricting means so as to prevent the sudden change of engine brake feeling caused by upshift. When the oil temperature reaches the specified temperature higher than the change point to high oil temperature, a restriction releasing means releases this restriction.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides a hold mode for fixing the gear stage of an automatic transmission according to a selected range, and a high oil temperature pattern to prevent a decrease in durability due to an increase in oil temperature. The present invention relates to a control device for an automatic transmission.

0002

2. Description of the Related Art Automatic transmissions have been known in which a hold mode is added to the shift pattern of an automatic transmission, thereby making it possible to fix the gear position in accordance with a selected range. The shift to the hold mode is performed by the driver's button operation, thereby enabling gear shifting operations similar to those of a manual transmission according to the driver's intention. In this case, for example, if the driver does not like shifting between 3rd and 4th gear while driving at high speed, D(
By selecting the hold mode of the drive) range, the gear position can be fixed at 3rd speed.

[0003] Furthermore, the torque converter hydraulic fluid of an automatic transmission tends to reach a high temperature in a high speed range. Therefore, in order to prevent a decrease in durability due to such a rise in oil temperature, when the oil temperature rises above a certain level, the low gear range and lock Control may be performed to automatically shift to a high oil temperature pattern with an enlarged up region. For example, in the automatic shift control device for a vehicle automatic transmission described in Japanese Patent Publication No. 48-217, when the oil temperature is high, the shift pattern is switched to a shift pattern that widens the low gear range.

0004

[Problems to be Solved by the Invention] However, when the oil temperature is automatically shifted to the high oil temperature pattern when the oil temperature is high as described above, especially in a control device for an automatic transmission having a hold mode, for example, If the oil temperature rises and enters the high oil temperature pattern when the vehicle speed is, for example, 120 km/h in hold mode (3rd gear fixed) and the accelerator is released to apply engine braking, Regardless of the driver's will, the fourth gear locks up and the deceleration suddenly drops, causing problems such as loss of engine braking effectiveness or engine braking feel.

The present invention has been made in view of the above-mentioned problems, and is intended to prevent engine engine feel from being impaired due to a shift to a high oil temperature pattern while a vehicle with an automatic transmission is running under engine braking. The purpose is to

[0006]

[Means for Solving the Problems] As shown in FIG. 1, the configuration of the automatic transmission control device according to the present invention is to control the automatic transmission according to a predetermined shift pattern including a hold mode based on various input information. A shift control means outputs a shift control signal to a shift control circuit, and when the oil temperature of the automatic transmission reaches a predetermined high temperature, the shift pattern is changed to a predetermined high oil temperature in which a lower gear range is expanded than usual. In a control device for an automatic transmission having a shift pattern changing means for changing to a high oil temperature pattern, when the engine load is below a predetermined level when running in a hold mode, the shift pattern changing means restricts the change to a high oil temperature pattern. It is characterized by comprising pattern restriction means.

[0007] The high oil temperature pattern may also have a lockup region that is larger than that of the normal shift pattern.

Further, the high oil temperature pattern limiting means changes to the high oil temperature pattern on the condition that the engine load is below a predetermined value while driving in the hold mode, and the vehicle speed is above a predetermined value. may be limited.

[0009] In addition to the above-mentioned configuration, a restriction release means may be provided for releasing the restriction by the shift pattern changing means when a predetermined temperature higher than the temperature at which the oil temperature pattern is changed to the high oil temperature pattern is reached. can.

0010

[Operation] The shift control means outputs a shift control signal to the shift control circuit of the automatic transmission according to a predetermined shift pattern based on various input information such as vehicle speed and engine load.
Accordingly, shift control of the automatic transmission is performed. Also,
When the oil temperature of the automatic transmission reaches a predetermined high temperature,
The shift pattern changing means automatically changes the shift pattern to a high oil temperature pattern, and shift control is performed using a pattern in which the lower gear range is expanded than usual. However, when running in hold mode and the engine load is below a predetermined level, the high oil temperature pattern limiting means restricts changes to the high oil temperature pattern, thereby preventing sudden changes in engine engine feel due to upshifts. .

[0011] The above effect is the same in the case where the oil temperature pattern has a high oil temperature pattern in which the lock-up region is expanded as well as the low-speed gear region.

Furthermore, by adding a predetermined vehicle speed or higher as an operating condition for the high oil temperature pattern limiting means, it is possible to efficiently maintain the engine engine feel during hold mode driving, particularly in areas where high demands are made. Can be done.

Furthermore, by releasing the restriction by the shift pattern limiting means when a predetermined temperature on the higher side than the temperature at which the temperature is changed to the high oil temperature pattern is reached, the high oil temperature is unconditionally maintained when the temperature exceeds the limit temperature. You can switch to a pattern.

[0014]

[Embodiment] Hereinafter, an embodiment will be explained based on the drawings.

FIG. 2 is an overall system diagram of one embodiment of the present invention. In this embodiment, an automatic transmission 2 connected to an engine 1 is a hydraulic automatic transmission consisting of a torque converter and an auxiliary transmission device, and a hydraulic control circuit 3 for controlling gear shifts is a lock-up automatic transmission. Electromagnetic solenoid 4
and electromagnetic solenoids 5, 6, and 7 for shifting between 1st and 2nd speeds, 2nd and 3rd speeds, and 3rd and 4th speeds. A control unit 8 is provided to control these electromagnetic solenoids 4 to 7.
A throttle valve opening signal from a throttle sensor 10 attached to a throttle valve 9 of the engine 1 and a turbine rotation speed signal from a turbine rotation speed sensor 11 attached to an output shaft of a torque converter of an automatic transmission 2 are input. , and also D (drive) depending on the driver's will.
, S (sporty) and L (low) ranges and a mode of economy, power, and hold. Temperature etc. are input. The control unit 8 is
Based on these input signals, a shift signal is outputted to each of the shift electromagnetic solenoids 5 to 7 according to a predetermined shift pattern, and a lockup signal is outputted to the lockup electromagnetic solenoid 4.

The shift pattern of this embodiment consists of three ranges, D, S, and L. The D range has power mode, economy mode, and hold mode, and the S and L ranges have power and economy common. The shift mode and hold mode are each set as a shift map. Here, in the economy mode, the high speed gear is set to a relatively low vehicle speed side with emphasis on fuel efficiency, and in the power mode, the high speed gear is set on the high vehicle speed side with emphasis on output. Further, the hold mode is to fix the gear position basically at 3rd gear in the D range, 2nd gear in the S range, and 1st gear in the L range. Further, in this embodiment, a high oil temperature pattern (HT mode) is set for each range as a shift pattern when the oil temperature of the automatic transmission 2 becomes high.

[0017] In the control unit 8, the gear position is determined according to the vehicle speed (calculated from the turbine rotation speed) and the throttle opening (corresponding to the engine load) based on the respective gear shift map, depending on the gear shift mode selected by the driver. .

FIG. 3 shows a shift map for the economy mode in the D range, FIG. 4 shows a shift map for the hold mode in the D range, and FIG. 5 shows a shift map for the HT mode in the D range. Each shift map has vehicle speed on the horizontal axis and throttle valve opening on the vertical axis, and each shift line for upshift and downshift, as well as the lockup activation line and lockup release line, are set respectively. be. In the economy mode shift map shown in Figure 3, the right arrow indicates, for example, 3
The solid line marked →4 is the shift up line (in the case of 3→4, the shift up line from 3rd to 4th gear), and the dashed line with a leftward arrow marked, for example, 3←4, is the shift down line. line (if 3←4, downshift line from 4th gear to 3rd gear) is shown, and →3L/U and →
The dash-dotted lines marked 4L/U indicate the lock-up operating lines for 3rd and 4th gears, respectively, and 3L/U← and 4L/U
The two-dot chain lines marked with ← indicate the lock-up release lines for 3rd and 4th gears, respectively. In addition, in the hold mode shift map shown in Figure 4, the gear stage is basically fixed at 3rd gear, but from the viewpoint of ensuring starting performance and preventing overrun,
A region for shifting to 2nd speed is set on the low vehicle speed side, and a region for shifting to 4th speed is set on the high vehicle speed side. Additionally, the shift map for the HT mode in Figure 5 is basically one in which the low gear range is expanded compared to the economy mode in Figure 3, and the lock-up range of each gear is expanded toward the lower vehicle speed side. .

As described above, switching to the hold mode is performed at the driver's will. For example, if the hold mode in the D range is selected while driving at high speed, the vehicle will be fixed at 3rd speed at a vehicle speed of 120 km/h, for example.

[0020] Furthermore, switching to the HT mode is basically performed when the oil temperature (TATF) reaches a predetermined switching setting temperature (TH2).
This is done when the However, in the hold mode, if the vehicle speed (VSP) is higher than the set vehicle speed (VHT) and the throttle valve opening is zero (idle switch signal is on), even if the switching set temperature (TH2) is exceeded. Do not switch to HT mode. Note that when the throttle valve opening is no longer zero, switching to the HT mode is performed after a certain period of time (within 5 seconds) from that point. Further, when the oil temperature (TATF) further increases and exceeds the limit temperature (TH1, where TH1>TH2), the mode is unconditionally switched to the HT mode.

Although the D range has been described above, similar control is performed for the S range and the L range in this embodiment.

Next, the above control of this embodiment will be explained with reference to the flowchart of FIG. Note that S1 to S8 indicate each step.

[0023] When starting, first, it is checked in S1 whether or not the hold mode is on.

If NO in S1 (not in hold mode), it is checked in S2 whether TATF>TH2, and if TATF>TH2, the HT mode is turned on in S3.

If YES in S1 (hold mode), it is determined in S4 whether TATF>TH1. And if TATF>TH1, then S3
Go to and turn on HT mode.

If NO in S4 (TATF≦TH1), the process goes to S5 to determine whether TATF>TH2. Then, if TATF>TH2, VS in S6 and S7
It is sequentially determined whether P≧VHT and whether the idle switch signal is on. If VSP≧VHT and the idle switch signal is on, the process goes to S8 and the HT mode is turned off.

[0027] Also, NO (VS
If P<VHT or the idle switch signal is off), the process goes to S3 and the HT mode is turned on.

[0028] When NO in S2 (TATF≦TH2),
And when NO (TATF≦TH2) in S5, S8
to turn off HT mode.

In the above embodiment, switching to the high oil temperature pattern is prohibited only when the throttle valve opening is zero (idle switch signal is on); however, switching to the high oil temperature mode is prohibited. It is also possible to perform this in a low load region where the throttle valve opening is equal to or less than a predetermined opening.

[0030]

[Effects of the Invention] Since the present invention is constructed as described above, it is possible to prevent engine engine feeling from being impaired due to a shift to a high oil temperature pattern when a vehicle with an automatic transmission is running under engine braking. Can be done.

[Brief explanation of the drawing]

[Figure 1] Overall configuration diagram of the present invention

[Figure 2] Overall system diagram of one embodiment of the present invention

[Figure 3] Shift map of economy mode in D range of the same example

[Figure 4] Shift map in hold mode in D range of the same example

[Figure 5] Shift map of HT mode (high oil temperature pattern) in D range of the same example

[Figure 6] Flowchart for executing control in the same embodiment

[Explanation of symbols]

1 Engine 2 Automatic transmission 3 Hydraulic control circuit 4 Electromagnetic solenoid for lock-up 5 Electromagnetic solenoid for 1st speed - 2nd speed shift 6 2nd speed -
3rd speed shift electromagnetic solenoid 7 3rd-4th speed shift electromagnetic solenoid 8 Control unit 9 Throttle valve 10 Throttle sensor 11 Turbine speed sensor 12 Pattern select switch

Claims (4)

[Claims] 1. A shift control means for outputting a shift control signal to a shift control circuit of an automatic transmission according to a predetermined shift pattern including a hold mode based on various input information; In a control device for an automatic transmission having a shift pattern changing means for changing the shift pattern to a predetermined high oil temperature pattern in which a lower gear range is expanded than usual when the oil temperature becomes high, the engine load is lowered when running in a hold mode. 1. A control device for an automatic transmission, comprising: a high oil temperature pattern restricting means for restricting a change to a high oil temperature pattern by the shift pattern changing means when the oil temperature is below a predetermined value. 2. The control device for an automatic transmission according to claim 1, wherein the high oil temperature pattern has a lockup region that is also expanded compared to the normal shift pattern. 3. The high oil temperature pattern limiting means changes to the high oil temperature pattern on the condition that the engine load is below a predetermined level while the vehicle is running in the hold mode, and the vehicle speed is above a predetermined level. 3. The control device for an automatic transmission according to claim 1, wherein the automatic transmission control device is configured to limit: 4. Claims 1 and 2, further comprising a restriction release means for releasing the restriction by the shift pattern restriction means when a predetermined temperature higher than the temperature at which the oil temperature pattern is changed to the high oil temperature pattern is reached. or the automatic transmission control device according to 3.