JPH036390B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a shift control method for an automatic transmission used in vehicles such as automobiles, and particularly to a method for controlling the shift of an automatic transmission used in a vehicle such as an automobile, and in particular, a method for controlling a shock when the manual shift range is changed from the neutral range to the driving range. This relates to a shift control method that avoids this occurrence.

BACKGROUND ART Automatic transmissions used in vehicles such as automobiles generally include a hydraulic torque converter that is given rotational power by an internal combustion engine as a prime mover, and a plurality of gear stages that are provided with rotational power from the hydraulic torque converter. and a gear transmission as an auxiliary transmission that can be switched between the two, and the gear transmission can switch gears according to a predetermined shift pattern depending on the vehicle speed and the amount of depression of the accelerator pedal. It's summery.

In the automatic transmission for a vehicle as described above, the manual shift range is changed when the accelerator pedal is released and the vehicle speed is below a predetermined value that is zero or close to zero, that is, when the vehicle is substantially stopped. It is known that when the vehicle is switched from the neutral range to a driving range such as the D range, the output torque of the gear transmission increases rapidly, causing the vehicle to sink or shift shock.

In order to reduce the sinking of the vehicle and shift shock as described above, when the manual shift range is switched from the neutral range to a driving range such as the D range while the vehicle is stopped, the manual shift range is changed from the neutral range to the driving range such as the D range, without directly shifting to first gear. Japanese Patent Application No. 57-43636 filed by the same applicant as the present applicant describes a shift control method involving shotless N-D shift control in which a shift is made to the second or third gear and then downshifted to the first gear.
No. (Japanese Patent Application Laid-open No. 58-160658), this shift control method prevents a sudden change in the output torque of the gear transmission when the manual shift range is switched from the neutral range to the travel range. This reduces vehicle sinking and shift shock.However, when the manual shift range is switched from the neutral range to the driving range, the gear transmission first shifts to the second or third gear as described above. If the above-mentioned shift control is performed even when the accelerator pedal is immediately pressed to start the vehicle without waiting for a short period of time for the first speed to be ready for departure after being shifted to the first speed, When the power is on, a downshift from the second or third gear to the first gear is performed, which results in a rather large shift shock. In this case, the above-mentioned shotless N-D shift control is performed only when the manual shift range is switched from the neutral range to the driving range while the vehicle is stopped and the brake pedal is depressed. It is becoming more and more popular.

Problems to be solved by the invention According to the standard driving instructions for vehicles with automatic transmissions,
When switching the manual shift range from the neutral range to the driving range, the brake pedal is supposed to be depressed, but some drivers may switch the manual shift range from the neutral range to the driving range without depressing the brake pedal. Therefore, when the above-mentioned shockless N-D shift control is executed on the condition that the brake pedal is depressed, the shockless N-D shift control will not be performed at this time. Furthermore, in a front-wheel drive vehicle, if the manual shift range is switched from the neutral range to the drive range with the brake pedal not depressed and the parking brake tightened, the parking brake normally brakes only the rear wheels. As a result, the gear transmission is shifted to first gear without the above-mentioned shockless N-D shift control, causing the vehicle to squat, and the N-D shock is even greater than when the parking brake is not tightened. There is a possibility that it will be felt.

The present invention aims to solve the above-mentioned problems.

Means for Solving the Problems According to the present invention, the present invention provides an internal combustion engine, a hydraulic torque converter, and a gear transmission capable of switching between a plurality of gears, and the vehicle speed and the accelerator pedal are controlled. an automatic transmission that switches gears according to a predetermined shift pattern depending on the amount of depression of the engine, and the internal combustion engine drives the front wheels via the hydraulic torque converter and the automatic transmission. A method of controlling the speed change of the automatic transmission in a front-wheel drive vehicle, in which the accelerator pedal is released, the vehicle speed is below a predetermined value close to zero, and the parking brake is tightened. When the shift range is switched from the neutral range to the travel range, the speed change of the gear transmission is temporarily set to a gear higher than the lowest speed gear, and then the gear is set to the lowest speed gear. This is achieved by the following method.

Effects and Effects of the Invention According to the present invention, when the manual shift range is switched from the neutral range to the driving range while the parking brake is tightened, the above-mentioned shotless N-D shift control is performed. In a front-wheel-drive vehicle where the rear wheels are braked by tightening the brakes, the gear transmission of the automatic transmission is switched from the neutral state to the first speed gear without shotless N-D shift control, resulting in scouting. Inconveniences such as the resulting expansion of the N-D shock are reliably avoided.

EXAMPLES The present invention will now be described in detail by way of examples with reference to the accompanying drawings.

FIG. 1 schematically shows the configuration of an apparatus for carrying out the method for controlling the speed change of an automatic transmission for a vehicle according to the present invention. The automatic transmission 1 is well known in itself, and includes a three-element single-stage two-phase hydraulic torque converter 6 having a pump impeller 2, a turbine impeller 3, a stator impeller 4, and a direct coupling clutch 5. and the input shaft 7 is connected to the hydraulic torque converter 6.
The pump impeller 2, which is the input member of the hydraulic torque converter 6, is connected to the output shaft 101 of the internal combustion engine 100.
The internal combustion engine 100 is drivingly connected to the pump impeller 2 so that rotational power can be applied to the pump impeller 2 from the internal combustion engine 100.
The output shaft 9 of the gear transmission 8 is drivingly connected to a drive axle via a propulsion shaft and a differential gear, not shown.

The gear transmission 8 may be a general gear transmission of a planetary gear type, in which a plurality of frictional engagement devices such as hydraulically operated clutches and brakes are selectively engaged and operated in a predetermined combination. The gears are switched between a plurality of gear stages, for example, to achieve three forward speeds and one reverse speed.

The engagement operations of the frictional engagement devices of the direct coupling clutch 5 and the gear transmission 8 are performed by a hydraulic control device 10. The hydraulic control device 10 may have a well-known general structure, and includes three electromagnetic valves 11, 12, 13 and a manual shift lever (not shown) that is operated by a manual shift lever 14 operated by hand. It has a valve and a speed change valve, and controls the supply and discharge of hydraulic pressure to the frictional engagement device of the gear transmission 8 by opening and closing each of the electromagnetic valves 11 and 12, and shifts the gear transmission 8 between a plurality of gears and a neutral position. The engagement and release of the direct coupling clutch 5 are controlled by opening and closing the solenoid valve 13. The basic structure of this hydraulic control device 10 has already been proposed in Japanese Patent Application No. 55-69110 by the same applicant as the present applicant, and if a more detailed explanation of this hydraulic control is required, please refer to Please refer to the specification and drawings of Application No. 55-69110.

Opening/closing control of the electromagnetic valves 11 to 13 is performed by an electric control device 15 including a microcomputer. The control device 15 receives information regarding the vehicle speed from the vehicle speed sensor 16 and the throttle opening of the internal combustion engine 100 from the throttle opening sensor 17.
In other words, the shift position sensor 18 provides information regarding the amount of depression of the accelerator pedal, the shift position sensor 18 provides information regarding the shift range in which the manual shift range is set, and the foot brake switch 19 provides information regarding whether the brake pedal for braking the vehicle is being depressed. Information regarding whether or not the handbrake (parking brake) is operating is provided by the handbrake switch 20, and the solenoid valve 1 is activated in accordance with the information.
On-off electric signals are individually output to each of the terminals 1 to 13.

Next, the procedure for carrying out the speed change control method according to the present invention using the above-mentioned electric control device 15 will be explained with reference to the flowchart shown in FIG.

In the first step 1, the flag F is converted to O and the timer is reset. After step 1, proceed to step 2.

In step 2, various sensors as mentioned above are used.
And information is taken in from the switch. After step 2, proceed to step 3.

In step 3, the gear is changed according to the vehicle speed detected by the vehicle speed sensor 16 and the throttle opening detected by the throttle opening sensor 17 according to a shifting pattern determined in advance according to the vehicle speed and the throttle opening. A step Sχ is determined. After step 3, proceed to step 4.

In step 4, it is determined whether flag F is 1 or not. Flag F is a flag indicating that the manual shift range has been switched from the neutral range to the driving range such as the D range.
When F=1, the process proceeds to step 9, whereas when F=1, the process proceeds to step 5.

In step 5, it is determined whether the shift range determined by the operation of the manual shift lever 14 has been switched from the neutral range to a driving range such as the D range, 2 range, or L range based on the signal from the shift position sensor 18. A determination is made whether or not. When the manual shift range has been changed from the neutral range to the driving range, the process proceeds to step 7, whereas when the manual shift range has not been changed from the neutral range to the driving range, the process proceeds to step 6.

Step 6 is a step that is executed at all times except when the manual shift range is changed from the neutral range to the driving range, and in this step 6, the manual shift range determined in step 3 is executed. The gear position Sχ is written into the storage device as the control gear position S. After step 6, proceed to step 18.

In step 7, flag F is converted to 1. After step 7, proceed to step 8.

In step 8, the timer starts counting up. After step 8, proceed to step 9.

In step 9, it is determined whether at least one of the foot brake switch 19 and the hand brake switch 20 is closed, that is, whether the braking system of the vehicle is operating. If the braking system of the vehicle is operating, the process advances to step 10, and if the braking system of the vehicle is not operating, the process advances to step 14.

In step 10, it is determined whether the vehicle speed V detected by the vehicle speed sensor 16 is smaller than a predetermined value Vset (a small value close to zero). V≦
When Vset, proceed to step 11, and V≦Vset.
If not, proceed to step 14.

In step 11, throttle opening sensor 1
Based on the signal from 7, it is determined whether the throttle valve is in the fully closed position (idle opening position). If the throttle valve is in the fully closed position, proceed to step 12; if the throttle valve is not in the fully closed position, proceed to step 14.

In step 12, the throttle valve is in the fully closed position, that is, the accelerator pedal is released, the vehicle speed is below a predetermined value close to zero, and the brake pedal is depressed or the parking brake is tightened. This step is executed when the condition that the timer count value T is satisfied.
A determination is made as to whether or not is greater than a predetermined value _T1 .
When T≧T ₁ , proceed to step 15, and T≧T ₁
If not, proceed to step 13.

Step 13 is a step that is executed until the above-mentioned conditions are satisfied and a predetermined time determined by the predetermined value _T1 has elapsed after the manual shift range is switched from the neutral range to the driving range. In step 13, the first gear _S1 is written as the control gear S in the storage device. After step 13, proceed to step 18.

Step 14 is a step that is executed when the above-mentioned conditions are not satisfied even if the manual shift range is switched from the neutral range to the driving range. In this step 14, the flag F is converted to O, A timer reset is performed.
After step 14, proceed to step 13.

Step 15 is a step that is executed after a predetermined time T1 determined by a predetermined value _T1 has elapsed since the manual shift range was switched from the neutral range to the driving _range when the above-mentioned conditions were satisfied. , in this step 15, the count value T of the timer is a predetermined value greater than the predetermined value _T1 .
A determination is made as to whether T is greater than ₂ . T≧ _T2
, proceed to step 17, whereas T≧
If not T ₂ , proceed to step 16.

In step 16, a predetermined time determined by a predetermined value _T2 elapses after a predetermined time determined by a predetermined value _T1 has elapsed since the manual shift range was switched from the neutral range to the driving range under the conditions as described above. In step 16, the highest gear Smax that can be established in the current manual shift range is written in the storage device as the control gear S. . The highest gear Smax that can be achieved in each manual shift range varies depending on the manual shift range, and is the second gear when in the L range, the third gear when in the 2 range, and the highest gear in the D range. At some times, it is the highest speed of the gear transmission, and in the case of a three forward speed, one reverse speed change gear system, it is the third speed. step
After 16, proceed to step 18.

Step 17 is a step that is executed after a predetermined time determined by a predetermined value _T2 has elapsed since the manual shift range was switched from the neutral range to the driving range under the conditions described above. In 17, flag F
is converted to O and the timer is reset. After step 17, proceed to step 13.

In step 18, solenoid drive control of the electromagnetic valves 11 and 12 is performed in accordance with the control gear S written in the storage device. As a result, the gear position of the gear transmission 8 is switched and set according to the control gear position S. After step 18, return to step 2.

By performing speed change control according to the flowchart described above, the throttle valve is fully closed, that is, the accelerator pedal is released, the vehicle speed is below a predetermined value close to zero, and the brake pedal is not depressed or sideways. When the manual shift range is switched from the neutral range to, for example, the D range while the vehicle's braking system is braking by tightening the brakes, the timer set value will change from that moment onwards.
Until a predetermined time (extremely short time) determined by _T1 has elapsed, the solenoid is driven to achieve the first gear, and, for example, hydraulic pressure is supplied to engage the forward clutch of a gear transmission. Next, when the set value _T1 has elapsed from the instant, a solenoid is driven to achieve the third gear, for example.
In addition to the hydraulic pressure supply for engaging the forward clutch, hydraulic pressure supply for engaging the direct clutch of the gear transmission 8 and the second brake is started, and the three frictions of the forward clutch, direct clutch, and second brake are started. The third gear is actually achieved by engagement of the engagement device. In this embodiment, when the manual shift range is switched from the neutral range to the travel range with the above-mentioned conditions satisfied, the solenoid drive to achieve the first gear is first performed for a very short time. After this, the solenoid is driven to achieve the third gear, but the solenoid is driven for a very short time to achieve the first gear, and the forward clutch actually engages. Since the solenoid drive was previously performed to achieve the third gear, the first gear is not actually achieved at this time, and the third gear is first achieved after switching the manual shift range as described above. . By providing a difference between the hydraulic pressure supply start time for forward clutch engagement and the hydraulic pressure supply start time for direct clutch and second brake engagement, these three frictional engagement devices Compared to the case where the hydraulic pressure supplies are started at the same time, a decrease in the rise characteristics of the hydraulic pressure supply is avoided, and the third gear stage is achieved without a long time lag.

When a predetermined time determined by the set value _T2 has elapsed from the instant described above, the solenoid is driven to achieve the first gear, and the hydraulic pressure is discharged to release the direct clutch of the friction engagement device 8 and the second brake. and the first gear is achieved.

As mentioned above, the manual shift range is set to neutral even when the accelerator pedal is released and the vehicle speed is zero or below a predetermined value close to zero and the brake pedal is depressed and the parking brake is tightened. When switching from the range to the drive range, the third gear is first achieved,
Since the first gear is achieved after this, the vehicle sinks when the manual shift range is changed from the neutral range to the driving range even when the brake pedal is depressed and the parking brake is tightened. This avoids the occurrence of errors and large shift shocks.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto, and various embodiments are possible within the scope of the present invention. It will be clear to those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram schematically showing an embodiment of a vehicular automatic transmission that implements the speed change control method according to the present invention and a speed change control method used to implement the speed change control method, and FIG. 1 is a flowchart illustrating a method for controlling a speed change of an automatic transmission for a vehicle according to the present invention. 1... automatic transmission, 2... pump impeller, 3...
...Turbine impeller, 4...Stator impeller, 5...
...Direct coupling clutch, 6...Hydraulic torque converter, 7...Input shaft, 8...Gear transmission, 9...
Output shaft, 10...Hydraulic control device, 11-13...
Solenoid valve, 14...Manual shift lever, 15
... Electric control device, 16 ... Vehicle speed sensor, 17
...Throttle opening sensor, 18...Shift position sensor, 19...Foot brake switch, 20...Handbrake switch, 100...
...Internal combustion engine, 101... Output shaft.

Claims (1)

[Claims] 1 It has an internal combustion engine, a hydraulic torque converter, and a gear transmission that can switch between multiple gears, and switches the gears according to a predetermined gear shift pattern depending on the vehicle speed and the amount of depression of the accelerator pedal. a front wheel drive vehicle, wherein the internal combustion engine drives the front wheels via the hydraulic torque converter and the automatic transmission; When the manual shift range is switched from the neutral range to the driving range under the conditions that the pedal is released, the vehicle speed is below a predetermined value close to zero, and the parking brake is tightened, the gear transmission A method characterized by first setting a gear to a higher gear than a lowest speed gear, and then setting the gear to the lowest speed.