JP3535697B2 - Transmission control device for automatic transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission, and more particularly to an upshift control during downhill traveling.

[0002]

2. Description of the Related Art Heretofore, there has been known a shift control device configured to determine a shift stage based on a running resistance and a vehicle speed so as to shift to an optimum shift stage when traveling downhill (Japanese Patent Laid-Open No. 4-4).
351).

[0003]

By the way, as disclosed in Japanese Unexamined Patent Application Publication No. 4-4351, the configuration in which the shift speed at the time of downhill is determined based on the traveling resistance and the vehicle speed increases the traveling resistance. Or (the downhill slope becomes gentle),
When the vehicle speed increases, a higher gear is selected and an upshift is performed. However, since the upshift is performed in any case regardless of the operation of the driver, there is a possibility that a sudden shift occurs and the driver feels uncomfortable.

The present invention has been made in view of the above problems, and makes it possible to perform upshift control for traveling downhill without causing the driver to feel uncomfortable, thereby improving the performance of gearshift control in an automatic transmission. The purpose is to improve.

[0005]

Therefore, the invention according to claim 1 is configured as shown in FIG. In FIG. 1, the gradient estimating means estimates a value correlated with the gradient of the road surface,
The upshift request calculation means calculates an upshift request when traveling downhill on the basis of the gradient value estimated by the gradient estimation means.

On the other hand, the upshift timing calculating means calculates the upshift timing during non-downhill traveling. Then, the upshift determination means, when the upshift request is calculated by the upshift request calculation means, the actual upshift request corresponding to the upshift request based on the upshift timing calculated by the upshift timing calculation means. Determines upshift execution.

According to this structure, even if the upshift request is calculated based on the gradient value when the vehicle is traveling downhill, the actual upshift corresponding to the upshift request is not unconditionally executed but the non-downshift is performed. Whether to actually execute the upshift is determined based on the upshift timing when traveling on a slope. Note that the calculation of the upshift request at the time of downhill traveling based on the gradient value means, for example, the case where the upshift request is calculated when the downward gradient becomes gentle, based on the allocation of the shift speed according to the gradient value. In the configuration that estimates the state of the engine brake after shifting from the gradient value and controls to the shift stage where proper engine braking can be obtained, when an upshift request is calculated to avoid excessive effect of engine braking, Including.

According to another aspect of the invention, the upshift determining means calculates the upshift request by the upshift request calculating means, and the upshift timing calculating means calculates the upshift timing during non-downhill traveling. When it is determined that the upshift is to be performed, the upshift is determined to be executed. According to this configuration, the upshift request is calculated from the change in the gradient value and the upshift is performed at the upshift timing during non-downhill traveling, which is the same as during non-downhill traveling. The upshift will be executed at the timing when traveling downhill.

According to the third aspect of the present invention, the upshift timing calculating means calculates the upshift timing based on a shift map preset corresponding to the vehicle speed and the accelerator opening. According to this configuration, as the upshift timing during non-downhill traveling, the upshift timing is calculated from the shift map set in advance corresponding to the vehicle speed and the accelerator opening. The shift map is one in which an upshift line and a downshift line are set corresponding to the vehicle speed and the accelerator opening, and when the upshift line is crossed in a certain direction, the upshift timing is determined. To be done.

According to the fourth aspect of the invention, the upshift timing calculating means calculates the accelerator opening degree at which each vehicle speed is upshifted in the shift map as the upshift timing. According to this configuration, the accelerator opening that is upshifted at the current vehicle speed is obtained from the upshift line, and when the actual accelerator opening changes from a state above the accelerator opening as the upshift timing to a state below. , That is,
The time when the vehicle crosses the upshift line due to the decrease in the accelerator opening is determined as the upshift timing during non-downhill traveling.

[0011]

According to the first aspect of the present invention, the actual upshift corresponding to the upshift request based on the gradient value during downhill traveling is determined based on the upshift timing during non-downhill traveling. Therefore, there is an effect that it is possible to perform an upshift when traveling downhill without causing the driver to feel uncomfortable.

According to the second aspect of the invention, the effect that the actual upshift corresponding to the upshift request based on the gradient value during downhill traveling can be executed at the same timing as during non-downhill traveling. is there. According to the third aspect of the present invention, the upshift timing at the time of non-downhill traveling is obtained by obtaining the upshift timing at the time of non-downhill traveling from the shift map preset corresponding to the vehicle speed and the accelerator opening. There is an effect that it can be executed at a timing that does not give a person a feeling of strangeness.

According to the fourth aspect of the invention, there is an effect that it is possible to perform the upshift during the downhill traveling at the timing of the accelerator operation when the upshift is performed during the non-downhill traveling.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 2 is a diagram showing a power system of a vehicle including an automatic transmission. In FIG. 2, the engine 1 mounted in the vehicle transmits the generated torque to vehicle drive wheels (not shown). Thus, the automatic transmission 2 is connected. The automatic transmission 2 includes a torque converter 3 for inputting a torque generated by the engine 1 through a fluid, a multi-stage speed change gear mechanism 4 for inputting an output of the torque converter 3 and changing and outputting the same, and drives these. And a hydraulic mechanism that operates.

Solenoid valves 6A and 6B are incorporated in the hydraulic mechanism of the speed change gear mechanism 4. By switching the combination of opening and closing of the solenoid valves 6A and 6B, each clutch included in the speed change gear mechanism 4 is changed. The combination of engagement and disengagement of the
The gear is changed to the 4th speed. The ON / OFF control of the plurality of solenoid valves is performed by the CPU,
This is performed based on a control signal from a control unit 50 containing a microcomputer including a ROM, a RAM, an A / D converter, an input / output interface and the like.

Signals from various sensors are input to the control unit 50. The various sensors include a throttle sensor 7 that detects an opening TVO (accelerator opening) of a throttle valve that opens and closes in conjunction with an accelerator, and the automatic transmission 2 described above.
A vehicle speed sensor 8 and the like for detecting the rotation speed of the output shaft (output shaft 5) of the vehicle and the vehicle speed VSP are provided.

A flow chart shown in FIG. 3 shows the shift control during downhill traveling performed by the control unit 50 having the functions of the gradient estimating means, the upshift request calculating means, the upshift timing calculating means and the upshift determining means. Follow the instructions below. In the flowchart of FIG. 3, in step 1 (denoted as S1 in the drawing; the same applies hereinafter), the throttle opening TVO, the vehicle speed VSP, the current gear position (gear position) GP, etc. are acquired.

In step 2, the gradient of the road surface of the vehicle is estimated and calculated. To estimate the road surface gradient, for example, turbine torque (output shaft torque of the torque converter) is calculated from the turbine rotation speed and throttle opening, and the driving force is calculated based on the turbine torque and the gear position, while rolling is performed based on the vehicle speed. Estimating air resistance, further obtaining acceleration resistance from the acceleration obtained as the amount of change in vehicle speed, and subtracting rolling / air resistance and acceleration resistance from the driving force to obtain gradient resistance (running mainly with gradient resistance. Resistance). However, the method of estimating the gradient value is not limited to the above.

At step 3, it is judged from the gradient estimation result at step 2 whether or not the traveling road surface of the vehicle is a downhill. If it is not a downhill, the routine proceeds to step 5, where a normal shift map is displayed. Based on this, the shift control is executed. The normal shift map is one in which an upshift line (see FIG. 4) and a downshift line are set according to the vehicle speed VSP and the throttle opening (accelerator opening) TVO, and the upshift line is set to a low value. Upshift is performed when the vehicle crosses from the vehicle speed side to the high vehicle speed side or from the high opening side to the low opening side, and the downshift line is changed from the high vehicle speed side to the low vehicle speed side or from the low opening side to the high opening side. A downshift will be made if the vehicle crosses.

On the other hand, when it is determined in step 3 that the vehicle is traveling downhill, the routine proceeds to step 4, where the gear position (gear position) is determined by the shift control for traveling downhill. Here, in the shift control at the time of traveling on a downhill, for example, a configuration in which the shift stage is determined with reference to a map in which the shift stage is assigned according to the vehicle speed and the slope (running resistance), and the downgrade is gentle Sometimes normal vehicle speed and throttle opening (accelerator opening)
On the other hand, when the downhill gradient is steep, the gear is controlled to a predetermined gear (for example, 3rd speed), the gradient value, the current gear GP, etc. Any configuration may be used such that the state is estimated and the gear is controlled to a shift stage in which an appropriate engine brake is obtained.

In step 6, it is determined whether or not an upshift request has been issued by the determination of the downshifting gear in step 4, that is, the gear higher than the current gear GP is determined. It is determined whether or not. Then, when the upshift request is not issued, the routine proceeds to step 8 to shift the gear to the target shift speed determined at step 6.

On the other hand, when an upshift request is issued, the routine proceeds to step 7, where the normal shift map is referred to based on the current shift stage (gear position) and vehicle speed VSP.
The upshift timing (TVOup for upshift) during non-downhill traveling is calculated. For example, when an upshift request of 3rd speed → 4th speed is requested, as shown in FIG. 4, an upshift is performed corresponding to the current vehicle speed VSP on the 3rd speed → 4th speed upshift line of the normal shift map. The throttle opening (accelerator opening) TVOup is obtained as the upshift timing during non-downhill traveling.

In step 9, the upshift timing TVOup is compared with the throttle opening TVOold at the previous execution of this routine. Then, the opening degree TVOold from the previous time is more than the upshift timing TVOup.
If is larger, the routine proceeds to step 10, where the upshift timing TVOup is compared with the latest opening TVO acquired at step 1 this time.

When it is determined in step 10 that the latest opening TVO is less than or equal to the upshift timing TVOup, that is, the throttle opening (accelerator opening) changes from the opening larger than the upshift timing TVOup. When the timing is less than the upshift timing TVOup, the routine proceeds to step 11, where the upshift is actually executed in response to the upshift request based on the shift control for downhill traveling determined in step 6. .

On the other hand, when the throttle opening change, which is the upshift pattern during non-downhill traveling, is not shown,
Step 11 is bypassed to step 12 without actually upshifting in response to the upshift request. In step 12, the throttle opening (accelerator opening) TVO acquired this time is set to the previous value TVOold.

According to the above configuration, even if an upshift request is generated by a gear position determined based on the gradient value or the like when traveling on a downhill, the upshift is not immediately performed in accordance with the upshift request. Normal (when driving downhill)
In the shift map of, the upshift is executed at the timing when the same type of upshift is performed.
It is possible to cause the driver to perform an upshift based on the gradient value or the like when traveling on a downhill without causing the driver to feel discomfort.

Further, by setting the upshift timing in the normal (non-downhill traveling) shift map as the upshift timing based on the accelerator operation, the downshift is performed at the timing corresponding to the accelerator operation by the driver. Upshift control for downhill can be performed, and the upshift control for downhill slope does not cause a driver to feel uncomfortable as a sudden shift.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of the invention according to claim 1.

FIG. 2 is a system diagram showing a power system of the vehicle in the embodiment.

FIG. 3 is a flowchart showing shift control for traveling on a downhill in the above embodiment.

FIG. 4 is a diagram showing upshift timing during non-downhill traveling.

[Explanation of symbols]

1 engine 2 automatic transmission 3 Torque converter 4 speed change gear mechanism 7 Throttle sensor 8 vehicle speed sensor 50 control unit

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-8-142711 (JP, A) JP-A-7-127720 (JP, A) JP-A-7-4506 (JP, A) JP-A-5- 10433 (JP, A) JP-A-4-4531 (JP, A) Actual development Sho 62-119555 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16H 59/00-61 / 12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (4)

(57) [Claims] 1. A gradient estimating means for estimating a value correlating to a gradient of a road surface, and an upshift request calculating means for calculating an upshift request during downhill traveling based on the gradient value estimated by the gradient estimating means. An upshift timing calculating means for calculating an upshift timing during non-downhill traveling; and an upshift timing calculated by the upshift timing calculating means when an upshift request is calculated by the upshift request calculating means. And an upshift determining unit that determines whether to actually execute an upshift corresponding to the upshift request, and a shift control device for an automatic transmission. 2. The upshift determining means, when the upshift request is calculated by the upshift request calculating means, and when the upshift timing during non-downhill traveling is determined by the upshift timing calculating means. The shift control device for the automatic transmission according to claim 1, wherein execution of upshift is determined. 3. The upshift timing calculation means,
3. The shift control device for an automatic transmission according to claim 1, wherein the upshift timing is calculated based on a shift map preset corresponding to the vehicle speed and the accelerator opening. 4. The upshift timing calculation means,
4. The shift control device for an automatic transmission according to claim 3, wherein an accelerator opening degree at which each vehicle speed is upshifted is calculated as an upshift timing in the shift map.