JP2002013625A - Speed-change controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speed-change controller, capable of shifting-down to an optimum stage by properly skipping gear stages, when automatically controlling a multi-stage transmission. SOLUTION: This speed change controller for controlling a speed change timing, while applying a two-dimensional map of an engine speed or a car speed and an acceleration opening as a speed change control map, comprises a target engine speed determining part 7 for determining a target engine speed, after the shifting-down on the basis of the acceleration opening when the shifting-down is requested, a shifting-down gear stage determining part 8 for determining the gear stage forecasted to be the optimum gear stage to obtain the engine speed which is closet to the target engine speed, determined by the target engine speed determining part 7 after the speed change, among gear stages which are lower than the present gear stage by more than one stage, as a target gears stage, and an automatic speed change control-part 9 for controlling the automatic speed change operation for shifting-down, on the basis of the target gear stage determined by the shifting-down gear change determining part 8.

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.

[0002]

2. Description of the Related Art Generally, in a transmission of a vehicle in which a vehicle mass (load) greatly fluctuates, such as a tractor for pulling a trailer or a large truck, an auxiliary transmission for switching a gear position between a high speed side and a low speed side. For example, when the vehicle is running under a high load such as loading luggage, the sub-transmission is switched to the lower gear to increase the drive torque transmitted to the drive wheels, and the vehicle runs in an empty state. Under such a low load, the fuel efficiency can be improved by switching the subtransmission to the high speed side.

In such a multi-stage transmission with an auxiliary transmission, a mechanical clutch similar to that of a manual transmission, a clutch actuator for connecting and disconnecting the clutch, and a shift actuator for switching a gear shift position are provided. A mechanical automatic transmission (or semi-automatic switchable to manual mode as needed) mainly comprising a select actuator for switching a gear select position so that a shift can be performed without stepping on a clutch pedal during traveling. Transmission) has already been developed,
In recent years, some tractors have 16 gears in order to increase the range of use of trailers that can be towed.

[0004]

However, in this kind of conventional automatic transmission, a target shift speed and a shift timing are uniquely set using a two-dimensional map based on the vehicle speed and the accelerator opening as a control map. As a result, the vehicle is shifted down one step at a time when the vehicle speed decreases during deceleration or climbing a hill. The gears are successively set to the lower gear, and a plurality of downshifts are performed continuously in a short period of time, so that drivability (response and smoothness from the vehicle to the driver's intention can be obtained) There is a problem that the feeling of whether or not it can be remarkably impaired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and when automatically controlling a multi-stage transmission, a shift control device capable of appropriately jumping over a shift speed and downshifting to an optimum shift speed. The purpose of this is to improve drivability by providing.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a shift control apparatus for controlling a shift timing using a two-dimensional map based on an engine speed or a vehicle speed and an accelerator opening as a shift control map. A target engine speed determining means for determining a target engine speed after downshifting based on the opening degree; and a target engine determined by the target engine speed determining means after shifting in a shift speed one or more lower than the current shift speed. Downshift stage determination means for determining a gear stage expected to be the engine speed closest to the engine speed as a target gear stage, and automatic downshifting based on the target gear stage determined by the downshift speed stage determination device. Automatic shift control means for controlling a shift operation.

Thus, when a downshift request is made, the target engine speed after downshift is determined by the target engine speed determination means based on the accelerator opening, and then the downshift operation is performed. In the gear determination step, a gear position expected to become the engine speed closest to the target engine rotation speed determined by the target rotation speed determination means after shifting in a gear position one or more stages lower than the current gear position is set as the target speed. The shift speed is determined, and the determined target shift speed is instructed to the automatic shift control means to control the automatic shift operation for downshifting, so that the optimal shift speed at which a good engine speed is maintained after shifting is achieved. It is possible to realize a skip downshift that shifts down gears by skipping gears as appropriate, Since appeared that are adapted to determine a target engine speed after downshifting based on the accelerator opening degree, it also becomes possible to realize the shift control that reflects the driver's intention.

Further, in the present invention, a vehicle mass detecting means for detecting a vehicle mass, a road surface gradient detecting means for detecting a road surface gradient, a vehicle mass and a road surface gradient detected by the vehicle mass detecting means and the road surface gradient detecting means. It is preferable to include a target engine speed corrector that appropriately corrects the target engine speed based on the above and outputs the target engine speed to the target engine speed determiner.

In this manner, the target rotation speed is appropriately corrected in accordance with a change in the load of the vehicle due to the vehicle mass or the road surface gradient. It is possible to avoid such a problem that power shortage occurs later.

[0010]

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

FIGS. 1 to 5 show an example of an embodiment of the present invention. As shown in FIG. 1, a shift control device according to the present embodiment has a control device including a computer device for performing calculations. The acceleration calculation unit 1, the driving force calculation unit 2, the vehicle mass calculation unit 3, the road surface gradient calculation unit 4,
The system includes a target rotation speed correction unit 5, a shift down request determination unit 6, a target rotation speed determination unit 7, a shift down gear position determination unit 8, and an automatic shift control unit 9.

That is, the acceleration calculation unit 1 inputs the shaft rotation speed information from the propeller shaft rotation sensor 10 mounted on the vehicle, converts it into a vehicle speed, and differentiates the vehicle speed with time to thereby instantaneously calculate the acceleration α. It is to be calculated.

In the driving force calculating section 2, an engine control computer 11 (ECU: Electronic Control) is provided.
Unit), the engine torque T is calculated based on the fuel injection amount information and the engine speed information.

[Number 1] is substituted into F = (T × ηm × i T / M × i dif) / R TIRE ... (1) and calculates the driving force of the vehicle.

In the relational expression (1), ηm indicates mechanical efficiency, i _{T / M} indicates a gear ratio, i _dif indicates a deflation ratio, and R _TIRE indicates a tire diameter. These are only known values. , The driving ratio calculating unit 2 has already input the gear ratio i _{T / M.} The gear ratio i _{T / M} is determined based on the gear position information from the gear position switch 12 mounted on the vehicle. Select and substitute.

The vehicle mass calculating section 3 recognizes the time of gear shifting based on the gear position information from the gear position switch 12 and the clutch stroke information from the clutch stroke sensor 13, and calculates the acceleration α before the gear shifting. ₁ and the deceleration α ₀ during gear shifting are taken in from the acceleration calculating unit 1 and the driving force F ₁ before gear shifting is calculated from the driving force calculating unit 2.
And the following relational expression (2)

The vehicle mass W is calculated by substituting W = F ₁ / (α ₁ −α ₀ ) (2).

Here, the relational expression (2) is obtained by solving a simultaneous equation of the equation of motion before the shift and the equation of motion during the shift.
The equation of motion before shifting is given by the following equation (3)

F ₁ −R = W × α ₁ (3) On the other hand, the equation of motion during shifting, in which substantial driving force is lost due to clutch disengagement, is represented by the following relational expression (4).

## EQU4 ## -R = W × α ₀ (4), and the relational expression (2) is obtained from the relational expression (3) -the relational expression (4). F
₁ , the vehicle mass W can be estimated by substituting the acceleration α ₁ before shifting and the deceleration α ₀ during shifting.

Further, the vehicle mass calculating section 3 integrates the calculated values of the past n times regarding the vehicle mass W, divides the total value by n + 1 and averages them to obtain the vehicle mass W.
Is updated.

Here, at the time of initial setting, an appropriate initial value is set, and at the time of the first shift from the initial setting, the initial value and the first calculated value are integrated to obtain "2 (n + 1 ) ".

When the vehicle is a tractor for towing a trailer, a different initial value is set depending on the presence or absence of a trailer pickup signal indicating that the trailer is connected (for example, 50 when the trailer pickup signal is ON).
It is preferable to set the time t and OFF when the time t is OFF.

When the vehicle mass W calculated by the vehicle mass calculation unit 3 is out of a predetermined range, for example, a range of 10 to 50 t, the calculation value is regarded as large and the detected value is excluded. After the calculation of the vehicle mass W is repeated 10 times or more from the initial setting, the vehicle mass W
The calculated value of the vehicle mass W out of the range of ± 50% with respect to the memory value is excluded.

When the power is turned on (including when the change of the trailer pickup signal continues for one second or more when the vehicle is a tractor for towing a trailer), the setting returns to the initial setting. Is continued for 5 minutes or more, the average calculation is newly performed with the final memory value, which is the average value of the vehicle mass W up to now, as an initial value.

Further, the road surface gradient calculating section 4 includes a vehicle mass W calculated by the vehicle mass calculating section 3, a current acceleration α calculated every moment by the acceleration calculating section 1,
The current driving force F calculated every moment by the driving force calculation unit 2 is inputted, and the following relational expression obtained by transforming the above-described equation of motion into a form for obtaining the running resistance R is provided. (5)

R = F− (W × α) (5) The running resistance R is calculated, and the running resistance R is calculated by the following relational expression (6).

R = (μrW + μcSV2 + Wsinθ) (6) to obtain the gradient resistance Wsinθ, and this gradient resistance W
sin θ is further divided by the vehicle mass W to obtain a road slope sin θ
Is calculated.

That is, when W is the vehicle mass, μr is the rolling resistance coefficient, μc is the drag coefficient, S is the vehicle cross-sectional area, V is the vehicle speed, and θ is the angle of inclination of the road surface with respect to the horizontal plane, the running resistance R becomes the rolling resistance. μrW and wind pressure resistance μcSV2
And the gradient resistance Wsinθ, it can be regarded as a sum of the resistance and the rolling resistance μ of the wheel from the running resistance R.
Subtracting rW and wind pressure resistance μcSV2 gives the slope resistance Wsin
θ can be obtained.

Although not specifically shown in FIG. 1, the road gradient calculating section 4 is made to input various information for grasping the driving state. During operation Manual clutch disengagement (in the case of semi-automatic transmissions, especially in the case of a vehicle with a manual clutch left when starting or stopping) During operation of the foot brake Excluding the driving state during operation of the retarder For example, the memory value of the road surface gradient sin θ is updated by averaging the calculated values of the past ten times (the number of times of calculation repeated in a very short time).

The vehicle mass W calculated by the vehicle mass calculation unit 3 and the road surface gradient sin θ calculated by the road surface gradient calculation unit 4 are input to the target rotation speed correction unit 5. The target engine speed corrector 5 appropriately corrects the target engine speed based on the vehicle mass W and the road surface gradient sin θ and outputs the target engine speed to the target engine speed determiner 7.

That is, the target rotation speed correction unit 5 has the configuration shown in FIG.
And a control map in which the vertical axis represents the accelerator opening and the horizontal axis represents the engine speed, the engine speed target line N indicated by a solid line is stored in the control map.
₁ , an engine speed target line N ₂ indicated by a dashed line,
Three pairs of target speed pattern is set in the engine speed target line N ₃ shown by the two-dot chain line, in the target rotational speed correction unit 5, either from these three sets of target speed pattern Is to be selected.

Here, when selecting any one of the three sets of target rotational speed patterns, the target rotational speed corrector 5
In FIG. 3, a gradient threshold value matrix as shown in FIG. 3 is programmed, and the gradient threshold value determined according to the vehicle mass W calculated by the road gradient calculating unit 4 is used to calculate the current value from the road gradient calculating unit 4. (In the table of the gradient threshold value matrix, sin θ is multiplied by 100 and expressed as a percentage) to select the target rotation speed pattern.

That is, when the vehicle mass W is heavy due to a load or the like, or when the road surface gradient sinθ is large when climbing a hill, the load on the vehicle is large, so that the power shortage after shifting down is considered. Therefore, the target line of the engine speed is positively shifted to the higher engine speed side.

As the target engine speed in this embodiment, an engine speed with good fuel efficiency at the time when the engine torque is generated most efficiently is appropriately selected.
It is the result of adding the increase and decrease according to the accelerator opening to the engine speed.Especially in a region where the accelerator opening is large, it is considered that the driver has a strong intention to accelerate by deeply depressing the accelerator pedal. As a result, the engine speed target lines N _{1 to} N ₃ are swung toward a higher speed to obtain a higher horsepower.

The shift-down request judging section 6 inputs the engine speed information from the engine control computer 11 and the accelerator opening information from the accelerator stroke sensor 14 mounted on the vehicle, respectively.
The current engine speed and the accelerator opening are illuminated on a shift control map held in an automatic shift control unit 9 described later to determine whether or not a downshift request has occurred.

Here, the shift control map held in the automatic shift control section 9 is, for example, as shown in FIG. 4, in which the vertical axis represents the accelerator opening and the horizontal axis represents the engine speed. Shift up line U and shift down line D
Is shifted up from the region between the shift-up line U and the shift-down line D when the shift to the right region is made over the shift-up line U, and the shift is made on the left side after the shift-down line D. It is set to shift down when shifting to the area.

FIG. 4 shows only a shift-up line U and a shift-down line D for a required shift speed for the sake of convenience of explanation, and substantially the same positions at positions corresponding to different engine speeds. It goes without saying that the shift-up line U and the shift-down line D are set for all the shift speeds.

The target rotation speed pattern selected by the target rotation speed correction unit 5, ie, the low load target line N ₁ ,
Either the medium load target line N ₂ or the high load target line N ₃ is input to the target rotation speed determination unit 7, and the shift down request determination unit 6 is provided to the target rotation speed determination unit 7. When information indicating that a downshift request has occurred is input, a target engine speed N _ET corresponding to the accelerator opening is determined in accordance with the target speed pattern fetched from the target speed corrector 5. Thus, the output is output to the downshift speed determination unit 8.

The shift down speed position determining unit 8 receives the target engine speed N _ET specified by the target speed determining unit 7 and the shaft speed N _out from the propeller shaft speed sensor 10 and inputs them. , The following relational expression (7)

## EQU7 ## The target gear ratio i _Target is calculated according to i _Target = N _ET / N _out (7), and the gear having the gear ratio i _{T / M} closest to the target gear ratio i _Target is selected. The gear position is determined as a target gear position for downshifting.

That is, in the downshift gear position determination section 8,
The target shift speed for downshifting is determined according to the flowchart shown in FIG.
After the target engine speed N _ET input from the target speed determination unit 7 is recognized in step S2, if the shaft speed N _out input from the propeller shaft rotation sensor 10 is recognized in step S2, At S3, the gear position at which the engine speed closest to the target engine speed N _ET is obtained after shifting is determined, and at Step S4, Step S3 is performed.
Is output to the automatic shift control unit 9 as the target shift speed.

Here, the automatic transmission control unit 9 performs a substantial automatic transmission operation of a mechanical automatic transmission (not shown) (or a semi-automatic transmission which can be appropriately switched to a manual mode), that is, a shift actuator and It is designed to control the operation of the select actuator,
The automatic shift control unit 9 receives the target shift speed determined by the shift down shift speed determination unit 8 and performs downshifting to the target shift speed.

Thus, according to the transmission control device configured as described above, the target rotation speed correction unit 5 is controlled by the vehicle mass calculation unit 3 and the road surface gradient calculation unit 4 based on the vehicle mass W and the road surface gradient sin θ. One of the three sets of target speed patterns is selected, and then when the shift-down request determining unit 6 recognizes that a downshift request has occurred, the target speed determining unit 7 sets the target speed. The target engine speed N _ET according to the accelerator opening is determined in accordance with the target speed pattern from the number corrector 5, and then the shift down speed determiner 8 determines that the target speed is one or more lower than the current speed. gear position is expected to be the engine speed is closest to the target engine speed N _ET determined by the target speed determining section 7 after shifting in the shift speed is determined as the target gear position, the determination of Target gear automatic transmission control unit 9
The automatic shift operation for downshifting is controlled in accordance with the instruction of (1), so that it is possible to realize a skip downshift in which the shift down is performed by appropriately jumping over the shift speed to the optimal shift speed in which a good engine speed is maintained after shifting. This makes it possible to avoid a problem in which downshifts are continuously performed a plurality of times in a short time and drivability is significantly impaired.

Further, since the target engine speed after downshifting is determined based on the accelerator opening at which the driver's intention regarding acceleration / deceleration appears, the shift control reflecting the driver's intention is performed. It can also be achieved.

Further, in this embodiment, the vehicle mass W and the road gradient sin θ are detected by the vehicle mass calculation unit 3 and the road surface gradient calculation unit 4, and the target rotation speed correction unit is detected based on the vehicle mass W and the road surface gradient sin θ. 5, the target engine speed pattern is changed to appropriately correct the target engine speed N _ET , so that the vehicle mass W and the road surface gradient s are obtained.
The target engine speed N _ET can be appropriately corrected in accordance with the load change of the vehicle due to inθ, and there is a problem that power shortage occurs after a gear shift in the case of a steep ascending slope with a large load. Can be avoided.

The speed change control device of the present invention is not limited to the above embodiment, but may be a two-dimensional map adopting the vehicle speed instead of the engine speed as the speed change control map. It goes without saying that various changes can be made without departing from the spirit of the present invention.

[0041]

According to the above-described transmission control apparatus of the present invention, various excellent effects as described below can be obtained.

(I) According to the first aspect of the present invention, the shift down is performed by appropriately jumping over the shift speed and shifting down to the optimum shift speed at which a good engine speed is maintained after the shift. Therefore, it is possible to avoid a problem that a plurality of downshifts are continuously performed in a short time, thereby greatly improving drivability. Since the target engine speed after downshifting is determined based on the accelerator opening at which the driver's intention regarding acceleration / deceleration appears, shift control that reflects the driver's intention can also be realized.

(II) According to the second aspect of the present invention, the vehicle mass and the road surface gradient are detected by the vehicle mass detection device and the road surface gradient detection device, and the target rotational speed is determined based on the vehicle mass and the road surface gradient. Since the corrector corrects the target engine speed and outputs it to the target engine speed determiner, the target engine speed can be appropriately corrected according to the load change of the vehicle due to the vehicle mass or the road surface gradient. In this case, it is possible to avoid a problem that power shortage occurs after shifting, for example, on a steep slope with a large load.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a control map having three sets of target rotation speed patterns.

FIG. 3 is a table showing an example of a gradient threshold value matrix.

FIG. 4 is an explanatory diagram showing an example of a shift control map.

FIG. 5 is a flowchart illustrating a procedure for determining a target shift speed.

[Explanation of symbols]

3 vehicle mass calculation unit (vehicle mass detection means) 4 road surface gradient calculation unit (road surface gradient detection means) 5 target rotation speed correction unit (target rotation speed correction unit) 7 target rotation speed determination unit (target rotation speed determination unit) 8 shift Down shift stage determination unit (shift down shift stage determination unit) 9 Automatic shift control unit (automatic shift control unit)

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Claims (2)

[Claims] 1. A shift control device for controlling a shift timing using a two-dimensional map based on an engine speed or a vehicle speed and an accelerator opening as a shift control map. A target engine speed determining means for determining a target engine speed; and an engine speed closest to the target engine speed determined by the target engine speed determining device after a shift in a shift speed one or more lower than the current shift speed. Downshift stage determining means for determining a gear stage expected to be a target gear stage, and automatic shift control for controlling automatic downshift operation based on the target gear stage determined by the downshift gear stage determining means And a shift control device. 2. A vehicle mass detecting means for detecting a vehicle mass, a road surface gradient detecting means for detecting a road surface gradient, and a target engine rotation based on the vehicle mass and the road surface gradient detected by the vehicle mass detecting device and the road surface gradient detecting device. 2. The transmission control device according to claim 1, further comprising a target rotation speed correction unit that appropriately corrects the number and outputs the rotation to the target rotation speed determination unit.