WO2018221747A1

WO2018221747A1 - Travel control device, vehicle, travel control method, and travel control program

Info

Publication number: WO2018221747A1
Application number: PCT/JP2018/021294
Authority: WO
Inventors: 恒高柳; 芳克井川; 享大 ▲徳▼山; 村田　直史; 圭介山本; 伊智郎粟屋; 貴規佐々木; 翼竹尾; 昇小島
Original assignee: 三菱自動車工業株式会社
Priority date: 2017-06-01
Filing date: 2018-06-01
Publication date: 2018-12-06
Also published as: JP2018202957A

Abstract

[Solution] A travel control device that executes constant-speed travel control and changing-speed control is provided with a target vehicle speed calculator, a target driving force calculator, a target output calculator, a constant-speed travel gear output unit, a changing-speed gear output unit, and a mediating unit. The changing-speed gear output unit has a downshift determination unit that determines whether or not a downshift is needed on the basis of a downshift threshold value and the target output. When the target output falls below the downshift threshold value and a downshift is determined to be needed, downshift control is performed, in which a changing-speed target gear is set to a value that is one gear downshifted from the current gear.

Description

Travel control device, vehicle, travel control method, and travel control program

The present invention relates to a travel control device, a vehicle, a travel control method, and a travel control program.

When the vehicle travels on a downhill road, the vehicle speed increases, so the vehicle operator (driver) needs to operate the brake, such as stepping on a brake pedal. Further, in the deceleration operation, AT (Automatic Transmission) is the maximum gear stage and the deceleration force is insufficient, and it takes time to decelerate. This is because AT is not downshifted, so AT has the maximum gear, that is, the minimum gear ratio, and the engine brake does not work.
In such a case, in a device that controls the vehicle speed, which is generally called “cruise control”, the AT shifts down during downhill driving or deceleration operation where the actual vehicle speed exceeds the target vehicle speed. Executed.
For example, when a road gradient is estimated and it is determined that the road is a downhill road or a deceleration operation, a downshift is executed by feedforward control.
However, in order to estimate the road gradient, a complicated calculation needs to be performed.

Further, Patent Document 1 performs AT shift control by adjusting the driver requested driving force and the constant speed traveling requested driving force, and shifts when the constant speed traveling requested driving force falls below the driving force based on the maximum engine braking force of the vehicle. Disclose down.

Further, in the apparatus disclosed in Patent Document 1, since the determination is performed based on the driving force, the setting of the shift-up threshold differs depending on the vehicle speed, and the process is complicated.

Japan, JP 2007-038933 A

According to a certain aspect of the present invention, in the control for keeping the vehicle speed constant, the AT is shifted down so that the actual vehicle speed does not exceed the target vehicle speed when traveling on a downhill road or during deceleration operation without performing complicated calculations. Control is performed.

According to the first aspect of the present invention, the travel control device that performs the constant speed travel control for traveling the vehicle at the target vehicle speed and the shift control for performing an appropriate shift according to the travel state calculates the target vehicle speed. A target vehicle speed calculation unit, a target drive force calculation unit that calculates a target drive force for traveling at the target vehicle speed, a target output calculation unit that calculates a target output based on the target vehicle speed and the target drive force, A constant-speed traveling gear output unit that outputs, as a constant-speed traveling target gear step, a gear stage that causes the vehicle to travel at the target vehicle speed based on the target output, and is installed in parallel with the constant-speed traveling gear output unit, and the target output And a mediation unit that mediates between the constant speed travel target gear and the gear shift target gear and outputs the target gear to the automatic transmission. The shift gear output unit is a downshift that is an engine brake output when the current gear of the automatic transmission is shifted down by one stage, calculated based on the target output, engine brake torque, and engine speed. A downshift determining unit that determines whether or not downshift is necessary based on the threshold value. If the target output falls below the shift-down threshold value and it is determined that a shift-down is necessary, a shift-down control is performed to set the shift target gear to a value shifted down by one step from the current gear.

According to this aspect, the downshift control can be performed without performing a complicated calculation by using the target output. As a result, the engine braking force can be increased and the vehicle speed can be prevented from exceeding when the vehicle is traveling on a downhill road or decelerating in constant speed traveling control. In addition, since the engine brake output after the downshift control is set as the downshift threshold for determination, excessive downshifting can be prevented.

In the first aspect, the target output calculation unit may multiply the calculated target output by a predetermined coefficient so as to reduce the target output.

According to this aspect, the coefficient (gain) is multiplied by the target output used for the determination of the downshift control so as to reduce the sensitivity. For this reason, excessive shift down can be suppressed, and deterioration of passenger comfort and shift hunting (gear level fluctuation and instability) can be prevented.

According to the second aspect of the present invention, the transmission gear output unit has a shift-up determination unit. The shift-up determination unit is a deviation between the engine output generated by the fuel, the engine brake output at the current gear stage of the automatic transmission, and the engine brake output when the current gear stage is shifted up by one stage. It is determined whether or not the upshift is necessary based on the upshift threshold. When it is determined that the engine output generated by the fuel exceeds the shift-up threshold value and needs to be shifted up, the shift-up target gear stage is set to a value shifted up by one stage from the current gear stage. Is done.

According to this aspect, it is possible to perform the upshift control without performing a complicated calculation by using the target output that is uniquely determined regardless of the gear stage. Thereby, shift hunting can be prevented while maintaining the vehicle speed.
Further, when the road surface slope becomes gentle during traveling on a downhill road, several steps of upshifting will not occur at a time. For this reason, a passenger | crew's comfort deterioration can be prevented.
Further, when an acceleration operation is performed from a downhill road, it is possible to suppress the occurrence of several stages of shift up at a time.

In the second aspect, the engine output generated by the fuel may be multiplied by a predetermined coefficient so as to increase the engine output generated by the fuel.

According to this aspect, since the engine output generated by the fuel used for the determination of the upshift control is multiplied by the coefficient (gain), excessive shift up can be suppressed and deterioration of passenger comfort can be prevented. .

In the second aspect, when the engine speed after the shift target gear stage is shifted up by one stage from the current gear stage is below the lower limit value of the engine speed, It may be determined that no up is necessary.

According to this aspect, when the engine speed after the upshift is lower than the lower limit value of the engine speed, the engine is not shifted up, and therefore engine stall due to a low engine speed can be prevented.

In the first or second aspect, the downshift determination unit is configured such that the engine speed after the shift target gear stage is shifted down by one stage from the current gear stage exceeds an upper limit value of the engine speed. It may be determined that no downshift is necessary.

According to this aspect, when the engine speed after the downshift exceeds the upper limit value of the engine speed, the engine is not downshifted, so that it is possible to prevent the passenger comfort from being deteriorated due to the high engine speed. .

In the first or second aspect, the transmission gear output unit may include a timer that outputs an input value with a predetermined time delay. The timer may use outputs of the downshift determination unit and the upshift determination unit as input values.

According to this aspect, since the output of the shift target gear stage is delayed by the timer, frequent shift changes and deterioration of passenger comfort can be prevented. Further, it is possible to prevent a jump shift in which several stages of shift up occur at a time during constant speed traveling on a downhill road.

In the first or second aspect, the arbitration unit may compare the constant speed travel target gear and the shift target gear, and output the smaller one as the target gear.

According to this aspect, the appropriate target gear stage can be selected and output by the arbitration unit, and the shift target gear stage can be selected only when necessary.

A vehicle according to the third aspect of the present invention includes any one of the travel control devices described above.

According to the fourth aspect of the present invention, the travel control method for performing the constant speed travel control for traveling the vehicle at the target vehicle speed and the shift control for performing an appropriate shift according to the travel state calculates the target vehicle speed. A step of calculating a target driving force for traveling at the target vehicle speed, a step of calculating a target output based on the target vehicle speed and the target driving force, and a target vehicle speed based on the target output. A constant speed traveling target gear output step for outputting a gear stage for driving the vehicle as a constant speed traveling target gear step and the constant speed traveling target gear output step are performed in parallel, and a shift target gear step is output based on the target output. And a step of arbitrating between the constant speed travel target gear and the shift target gear and outputting the target gear to the automatic transmission. The shift gear output step is a downshift that is an engine brake output when the current gear stage of the automatic transmission calculated by the target output, engine brake torque, and engine speed is shifted down by one stage. And determining whether a downshift is necessary based on the threshold value. The shift gear output step sets the shift target gear to a value shifted down by one step from the current gear when the target output exceeds the shift-down threshold and it is determined that a shift-down is necessary. Shift down control is performed.

According to the fifth aspect of the present invention, the travel control program for performing the constant speed travel control for traveling the vehicle at the target vehicle speed and the shift control for performing an appropriate shift according to the travel state calculates the target vehicle speed. A step of calculating a target driving force for traveling at the target vehicle speed, a step of calculating a target output based on the target vehicle speed and the target driving force, and a target vehicle speed based on the target output. A constant speed travel target gear output step for outputting a gear stage for driving the vehicle as a constant speed travel target gear stage, and the constant speed travel target gear output step are performed in parallel, and a shift target gear stage is output based on the target output. And a step of arbitrating between the constant speed travel target gear and the shift target gear and outputting the target gear to the automatic transmission. The shift gear output step is a downshift that is an engine brake output when the current gear of the automatic transmission is shifted down by one step, calculated based on the target output, engine brake torque, and engine speed. And determining whether a downshift is necessary based on the threshold value. When it is determined that the target output exceeds the shift-down threshold and a shift-down is necessary, a shift-down control is performed to set the shift target gear to a value shifted down by one step from the current gear.

According to the travel control device, the vehicle, the travel control method, and the travel control program of the embodiment, the downshift determination is performed based on the downshift threshold value and the target output, so that the downshift control is performed without performing complicated calculations. be able to.

FIG. 1 is a block diagram showing constant speed traveling control according to the first embodiment. FIG. 2 is a block diagram showing the shift control according to the first embodiment. FIGS. 3A and 3B are graphs showing the relationship between the engine output and engine brake output and the engine speed according to the first embodiment. FIG. 4 is a flowchart showing the downshift control according to the first embodiment. FIG. 5A and FIG. 5B are graphs showing changes in engine brake output at the time of upshifting according to the second embodiment. FIG. 6A and FIG. 6B are time charts showing the vehicle speed and the gear stage after the deceleration operation on the downhill road according to the second embodiment. FIG. 7 is a flowchart showing the upshift control according to the second embodiment. FIG. 8 is a block diagram showing shift control using a timer according to the third embodiment. FIG. 9A and FIG. 9B are time charts showing road surface gradient, output, and gear stage when the timer according to the third embodiment is used. FIG. 10 is a block diagram illustrating control of the arbitration unit according to the fourth embodiment.

Hereinafter, a travel control device, a vehicle, a travel control method, and a travel control program according to an embodiment will be described with reference to the drawings.

[First Embodiment]
Hereinafter, a first embodiment will be described with reference to FIGS.
FIG. 1 shows a schematic configuration of a travel control device, a vehicle, a travel control method, and a travel control program according to the present embodiment.
As shown in FIG. 1, the travel control device 1 includes a target vehicle speed calculation unit 10, a target driving force calculation unit (FF) 20, a target driving force calculation unit (FB) 30, and a target engine torque calculation unit 40. The gear output unit 50 is provided as a main configuration. The travel control device 1 is mounted on a vehicle 90.
The vehicle 90 includes a transmission (automatic transmission) 91 and an engine 92 as main components.

In the vehicle 90, constant speed traveling control is performed, so that constant speed traveling is performed at the target vehicle speed.
The constant speed running control in this embodiment will be described below.
The target acceleration is calculated by the target acceleration calculator 11 of the target vehicle speed calculator 10, and the target vehicle speed is calculated by the target vehicle speed calculator 12.

Next, the target acceleration is input to the acceleration resistance calculation unit 21 of the target driving force calculation unit (FF) 20, the target vehicle speed is input to the running resistance calculation unit 22, and the calculated resistance is added to the vehicle 90. Resistance, that is, a target driving force (FF) corresponding to the resistance. The target driving force (FF) calculated in the target driving force calculation unit (FF) 20 is calculated by feedforward control.

On the other hand, the target vehicle speed is input to the target driving force calculation unit (FB) 30, and the deviation between the target vehicle speed and the actual vehicle speed input from the vehicle 90 is input to the PI controller 31 to calculate the target driving force (FB). Is done. The target driving force (FB) calculated by the target driving force calculation unit (FB) 30 is calculated by feedback control.

Next, the target driving force (FF) and the target driving force (FB) are added by an adder to obtain a target driving force, which is input to the target output calculation unit 51 of the gear output unit 50 together with the target vehicle speed. The target driving force is a target value of driving force for performing constant speed traveling at the target vehicle speed.
The target output calculation unit 51 calculates the target output by multiplying the target driving force and the target vehicle speed. The calculated target output is input to the shift determination unit 52, where it is determined whether a shift-up or a shift-up is necessary to obtain a gear according to the target output, and the target gear is transmitted to the transmission 91 of the vehicle 90. A stage is output.

Further, the target engine torque calculation unit 40 receives the target driving force, the tire radius, and the actual gear ratio from the vehicle 90, and calculates the target engine torque. The calculated target engine torque is output to the engine 92 of the vehicle 90.

Here, the traveling control device 1 includes, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program as an example, and the CPU reads the program into a RAM or the like to execute information processing / arithmetic processing. As a result, various functions are realized. The program is preinstalled in a ROM or other storage medium, provided in a state stored in a computer-readable storage medium, or distributed via wired or wireless communication means. Etc. may be applied. The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

Here, when the vehicle 90 that performs constant speed traveling control performs downhill road traveling or deceleration operation, the actual vehicle speed exceeds the target vehicle speed, so it is necessary to shift down the AT. In the present embodiment, the gear output unit 50 determines the shift change in the downhill traveling or the deceleration operation in parallel with the determination of the shift change in the constant speed traveling.

FIG. 2 is a block diagram showing the shift control according to this embodiment.
The gear output unit 50 includes a constant speed traveling gear output unit 55, a transmission gear output unit 56, and an arbitration unit 59 as main components.
The constant speed traveling gear output unit 55 includes a target output calculation unit 551 and a shift determination unit 552. The constant speed traveling gear output unit 55 outputs, as a constant speed traveling target gear stage, a gear stage that causes the vehicle 90 to travel at the target vehicle speed based on the target output.
The transmission gear output unit 56 is installed in parallel with the constant speed traveling gear output unit 55. The transmission gear output unit 56 includes a target output calculation unit 561 and a shift determination unit 562. The transmission gear output unit 56 outputs a transmission target gear stage based on the target output.
The arbitration unit 59 arbitrates between the constant speed traveling target gear stage output from the constant speed traveling gear output unit 55 and the shift target gear stage output from the transmission gear output unit 56, and the smaller one is set as the target gear stage. Output to transmission 91.

A target vehicle speed and a target driving force are input to the gear output unit 50. The target vehicle speed and the target driving force are input to both the constant speed traveling gear output unit 55 and the transmission gear output unit 56, respectively.
The target vehicle speed and the target driving force input to the constant speed traveling gear output unit 55 are input to the target output calculation unit 551 to calculate the target output (constant speed). The target output (constant speed) is input to the downshift determination unit 553 and the upshift determination unit 554 of the shift determination unit 552 and needs to be upshifted or upshifted to achieve a gear stage corresponding to the target output (constant speed). Is determined, and the target gear stage (constant speed) is output.

On the other hand, the target vehicle speed and the target driving force input to the transmission gear output unit 56 are input to the target output calculation unit 561 to calculate a target output (shift). The target output (shift) is input to the shift-down determination unit 563 and the shift-up determination unit 564 of the shift determination unit 562, and it is necessary to shift up or shift up to obtain a gear stage corresponding to the target output (shift). Is determined, and the target gear stage (shift) is output.

Here, the determination of the shift determination unit 562 in the transmission gear output unit 56 will be specifically described below.
In traveling at a constant speed, for example, when traveling on a downhill road, the actual vehicle speed exceeds the target vehicle speed, so the engine brake is used to decelerate. In this case, since a larger engine brake output can be obtained by shifting down by one stage, a determination is made using the target output of the vehicle 90 and the engine brake output when shifting down by one stage from the current gear stage. And
The engine brake output is calculated by multiplying the engine brake torque and the engine speed. Here, the engine brake torque may be set in advance with a map or constant defined for each engine speed, or the engine brake torque calculated by the engine ECU may be used. Good. Moreover, you may correct | amend with the load torque of auxiliary machines, such as an air conditioner of a vehicle 90, and an alternator.

3A and 3B are graphs showing the relationship between the engine output and engine brake output and the engine speed according to the present embodiment.
In the graph of FIG. 3A, the vertical axis represents output, the horizontal axis represents engine speed, and the vertical arrow direction is a positive direction. A one-dot chain line indicates the maximum output of the engine 92 of the vehicle 90, and a solid line indicates the engine brake output when the engine 92 is shifted down by one stage from the current gear stage.
In the graph of FIG. 3B, the vertical axis indicates the output, the horizontal axis indicates the engine speed, and the vertical axis arrow direction is negative, that is, a graph in which the output of the graph of FIG. It has become. The solid line indicates the engine brake output when the engine 92 is shifted down by one stage from the current gear stage.
As shown in FIG. 3 (a), the engine brake output is a negative output, and as the engine speed increases, the engine brake output decreases in the negative direction, that is, the absolute value increases. Since only the output in the negative direction is used in downhill traveling and deceleration operation, only the negative range of the graph in FIG. 3A is represented in FIG.

The target output (shift) calculated by the target output calculation unit 561 of the transmission gear output unit 56 in FIG. 2 is the output A (A <0) in the case of the engine speed ω ₁ in FIG. To do. In this case, since the target output (shift) exceeds the solid engine brake output in the negative direction, the shift determination unit 562 determines to perform a one-stage downshift. When downshifting by one stage, the engine speed increases in the direction of the thick arrow, and the target output (shift) and the engine brake output coincide with each other at the engine speed ω ₂ (see the points on the graph), and the engine that matches the target output (shift) Brake output can be obtained.
Therefore, the engine brake output when the gear is shifted down by one gear from the current gear is used as the shift-down threshold in the determination of the downshift.

Here, it is possible to use the engine brake output at the current gear stage as the shift down threshold, but by using the engine brake output when the current gear stage is shifted down by one stage, excessive shift down or Prevent frequent downshifts.

Further, the target output (shift) calculated by the target output calculation unit 561 of the transmission gear output unit 56 of FIG. 2 may be multiplied by a coefficient (gain). As the gain, a predetermined value is set so as to reduce the target output (shift).

FIG. 4 is a flowchart showing the downshift control according to this embodiment.
In step S401, the target output calculation unit 561 calculates a target output (shift), and the process proceeds to step S402.
Next, the downshift determination unit 563 calculates the engine brake output when the current gear stage is shifted down by one stage (S402), and proceeds to step S403.
Next, the downshift determination unit 563 determines whether or not the target output (shift) is below the engine brake output when the target gear (shift) is shifted down by one step from the current gear (S403). If it is determined that the value is below, the process proceeds to step S404. If it is determined not to fall below, the process proceeds to step S405.
In step S404, the downshift determination unit 563 determines that a downshift is necessary, and outputs a flag: 1.
In step S405, the downshift determination unit 563 determines that no downshift is necessary, and outputs a flag: 0.

In the present embodiment, in addition to the determination using the above-described shift-down threshold in the determination of the shift-down, the upper limit value of the engine speed that is the threshold when the engine speed is shifted down from the current gear by one step. You may provide the conditions of permitting a shift down when it is below (for example, 3000 rpm).

According to the present embodiment, by using the target output, it is possible to perform the downshift control without performing a complicated calculation. As a result, the engine braking force can be increased and the vehicle speed can be prevented from exceeding when the vehicle is traveling on a downhill road or decelerating in constant speed traveling control. Further, since the engine brake output after the downshift is set as the downshift threshold and the determination is performed, an excessive downshift can be prevented.

Further, according to the present embodiment, the target output used for the determination of the downshift control is multiplied by a coefficient (gain) so as to reduce the sensitivity, so that an excessive downshift is suppressed and the passenger comfort is deteriorated and shifted. Hunting can be prevented.

Further, according to the present embodiment, when the engine speed after the downshift exceeds the upper limit value of the engine speed, the engine is not downshifted, thereby preventing deterioration of passenger comfort due to the high engine speed. Can do.

[Second Embodiment]
Hereinafter, the second embodiment will be described with reference to FIGS.
In the first embodiment described above, the determination of downshifting is performed. In the second embodiment, the determination of upshifting is performed. Since the other points are the same as in the first embodiment, the same components are denoted by the same reference numerals and the description thereof is omitted.

FIGS. 5A and 5B are graphs showing the transition of the engine brake output at the time of upshifting according to the present embodiment.
5A and 5B, the vertical axis indicates the output, P _FUEL is the engine output generated by the fuel, P _L is the engine brake output at the current gear stage, and P _H is the current gear. The engine brake output when shifting up one stage from the stage is shown.

FIG. 5A shows each output before the upshift.
When the gradient becomes loose e.g. descending a slope in the running, the engine output generated by the fuel in the current gear position is P _FUEL and engine brake output shown in FIG. 5 (a) is a P _L shown in FIG. 5 (a), when the engine brake output when one stage upshift from the current gear position is assumed to be P _H of FIG. 5 (a), the engine brake output and the current gear position in the case of one stage upshift from the current gear P _FUEL is smaller than the deviation P _H -P _L from the engine brake output. Therefore, if the upshift is performed in this case, the engine brake output is insufficient, and the actual vehicle speed exceeds the target vehicle speed. This is because the output cannot be adjusted by the AT alone, and as a result, shift hunting occurs in which the gear stage fluctuates and becomes unstable.

Therefore, in this embodiment, the output is adjusted according to the engine torque request. Specifically, the deviation P _H − between the engine brake output when the engine output P _FUEL generated by fuel at the current gear stage is shifted up by one stage from the current gear stage and the engine brake output at the current gear stage. If P _L is exceeded, it is determined that a shift up is necessary.
Therefore, the difference P _H -P _L between the engine brake output when the current gear stage is shifted up by one stage and the engine brake output at the current gear stage is determined as the shift-up threshold value in the determination of the shift-up.

FIG. 5B shows each output immediately before the upshift.
The engine output P _FUEL generated by the fuel at the current gear stage is a value obtained by multiplying the target vehicle speed by the target driving force, that is, the target output (> 0). Since this P _FUEL exceeds the deviation P _H −P _L , a shift up is performed. At this time, the engine brake force is sufficient by the engine brake output after the upshift, and the target vehicle speed can be maintained. Therefore, shift hunting can be prevented.
In the above example, the difference P _H − between the engine brake output when the engine output P _FUEL generated by fuel at the current gear stage is shifted up by one stage from the current gear stage and the engine brake output at the current gear stage. Although it is determined that the upshift is necessary when exceeding P _L , the upshift may be performed when the following expression (1) is satisfied.

P _FUEL > (P _H −P _L ) × α + β (1)

In the formula (1), for example, α = 1.5 and β = 0 are preferable, but not limited to this, an appropriate value can be set according to control.

Further, the engine output P _FUEL generated by the fuel may be multiplied by a coefficient (gain). The gain is set to a predetermined value so as to increase the engine output P _FUEL generated by the fuel.

In this embodiment, since the upshift is performed after the engine torque is requested, the upshift is difficult compared to the case where the above determination is not made.
6 (a) and 6 (b), the vehicle speed and gear stage after the deceleration operation (COAST operation) on the downhill road are shown in the time chart. 6 (a) and 6 (b), the upper vertical axis indicates vehicle speed (km / h), the lower vertical axis indicates gear stage, and the horizontal axis indicates time (seconds). FIG. 6A is a time chart of the vehicle speed and gear stage when the travel control apparatus as a reference example is used, and FIG. 6B is a chart of the vehicle speed and gear stage when the travel control apparatus 1 of this embodiment is used. It is a time chart.
In both FIG. 6A and FIG. 6B, the deceleration operation is performed between time 0 and time 20.
When the traveling control device as a reference example is used as shown in FIG. 6A, when the deceleration operation is completed at time 20, the control (downhill road control) by the transmission gear output unit 56 is stopped and the upshift is performed. Is done. At this time, the gear stage changes from 3 to 7, and then 8. That is, a jump shift occurs in which a shift change of two or more stages is performed. Thereafter, downhill road control is resumed from time 30 and a downshift is performed. Thus, a shift busy that shifts up once occurs when an acceleration operation is performed from a downhill road.
On the other hand, when this embodiment is used, even if the deceleration operation is completed at time 20, as shown in FIG. This is because the shift up is performed after the engine torque is requested as described above, and therefore it is difficult to shift up compared to the case where the above determination is not performed.

FIG. 7 is a flowchart showing the upshift control according to this embodiment.
In step S701, the shift-up determination section 564 calculates an engine brake output P _L in the current gear position, the process proceeds to step S702.
Next, the upshift determination unit 564 calculates the engine output P _FUEL generated by the fuel at the current gear stage (S702), and proceeds to step S703.
Next, the shift-up determination section 564 calculates an engine brake output P _H in the case of one stage upshift from the current gear position (S703), it shifts to step S704.
Next, the upshift determining unit 564 determines whether or not the engine output P _FUEL exceeds the deviation P _H −P _L (S704). If it is determined that the engine output P _FUEL exceeds the deviation P _FUEL , the process proceeds to step S705. When it determines with not exceeding, it changes to step S706.
In step S705, the upshift determination unit 564 determines that the upshift is necessary, and outputs a flag: 1.
In step S706, the upshift determination unit 564 determines that the upshift is not necessary, and outputs a flag: 0.

In the present embodiment, in addition to the determination using the above-described engine output in the determination of the upshift, the engine speed when the current gear stage is shifted up by one stage is the lower limit value of the engine speed that is a threshold value. A condition of permitting upshifting when the speed is (for example, 1000 rpm) or more may be provided.

According to this embodiment, by using a target output that is uniquely determined without changing depending on the vehicle speed, it is possible to perform upshift control without performing complicated calculations. Thereby, shift hunting can be prevented while maintaining the vehicle speed.
Further, when the road surface slope becomes gentle during traveling on a downhill road, several steps of shift-up are not generated at a time, so that it is possible to prevent passenger comfort from deteriorating.
Further, when an acceleration operation is performed from a downhill road, it is possible to suppress the occurrence of several stages of shift up at a time.

Further, according to the present embodiment, when the engine speed after the upshift is below the lower limit value of the engine speed, the engine is not shifted up, and therefore engine stall due to a low engine speed can be prevented.

Further, according to the present embodiment, the engine output generated by the fuel used for the determination of the upshift control is multiplied by a coefficient (gain), so that excessive shift up is suppressed and deterioration of passenger comfort is prevented. Can do.

[Third Embodiment]
Hereinafter, the third embodiment will be described with reference to FIGS. 8 to 9B.
In the first embodiment described above, a shift-down determination is performed. In the second embodiment, a shift-up determination is performed. In the third embodiment, a timer is provided for a shift-down and a shift-up determination. Since the other points are the same as those of the first and second embodiments, the same reference numerals are given to the same components, and the description thereof is omitted.

FIG. 8 is a block diagram showing shift control using the timer according to the present embodiment.
As shown in FIG. 8, the timer 58 is provided between the transmission gear output unit 56 and the arbitration unit 59. The timer 58 delays the output of the transmission gear output unit 56 by a predetermined time and outputs it to the arbitration unit 59.

FIG. 9A and FIG. 9B show the road surface gradient, output, and gear stage when using the timer according to this embodiment in the time chart.
9 (a) and 9 (b), the upper vertical axis represents the road surface gradient, the middle vertical axis represents the target output, the lower vertical axis represents the gear stage, and the horizontal axis represents time. In the output time chart of the middle stage, the alternate long and short dash line indicates the downshift threshold, and the alternate long and two short dashes line indicates the upshift threshold. FIG. 9A is a time chart of road gradient, output, and gear stage when a travel control device as a reference example is used. FIG. 9B is a time chart of road gradient, output, and gear stage when the travel control device 1 provided with the timer 58 of the present embodiment is used.
Both FIG. 9A and FIG. 9B show a case where the road surface gradient becomes gentle at time t1 when traveling downhill on the road at a constant speed.
As shown in FIG. 9A, when the traveling control apparatus as a reference example is used, when traveling at a gear stage of 5, the gradient becomes gentle at time t1 and the target output increases. Since the target output exceeds the upshift threshold at time t2, the upshift is performed. At this time, since the target output is a value obtained by multiplying the target vehicle speed and the target driving force, the gear stage does not decrease immediately even if the gear is shifted up. The gear is shifted up to 8 and the gear is shifted up to 8. Thereafter, the target output continues to decrease, and the gear stage is shifted down from 8 to 7 because it falls below the downshift threshold at time t3. Since the gear stage has been shifted down, the value of the shift down threshold value is also changed to the engine brake output in the case where the current gear stage has been shifted down by one stage to 6.

On the other hand, when this embodiment is used, as shown in FIG. 9B, when traveling at a gear stage of 5, the gradient becomes gentle at time t1 and the target output increases. The target output exceeds the upshift threshold at time t5, but the upshift is confirmed at time t6 by the timer 58. Therefore, the target output decreases during the time t5 to t6, and the gear stage shifts up from 5 to 6. Thereafter, the target output rises again, the target output exceeds the upshift threshold at time t7, and the upshift to the gear stage: 7 is determined by the timer 58 at time t8.

According to the present embodiment, since the output of the shift target gear stage is delayed by the timer 58, frequent shift changes and deterioration of passenger comfort can be prevented. Further, it is possible to prevent a jump shift in which several stages of shift up occur at a time during constant speed traveling on a downhill road.

[Fourth Embodiment]
Hereinafter, the fourth embodiment will be described with reference to FIG.
In the first embodiment, the second embodiment, and the third embodiment, the arbitration unit outputs the smaller one of the constant speed travel target gear stage and the shift target gear stage as the target gear stage. In this embodiment, further conditions are provided. Since the other points are the same as those of the first embodiment, the second embodiment, and the third embodiment, the same components are denoted by the same reference numerals and the description thereof is omitted.

FIG. 10 is a block diagram showing the control of the arbitration unit according to the third embodiment.
The constant speed travel target gear stage is input from the constant speed travel gear output unit 55 to the arbitration unit 59. Further, the gear shift target gear stage is input from the transmission gear output unit 56 to the arbitration unit 59. The arbitration unit 59 selects a smaller one of the constant speed travel target gear stage and the shift target gear stage by the selector 591.

Next, a logical product is obtained by the logic gate 592. The logic gate 592 outputs 1 to the ON timer 595 when all the following conditions are satisfied.
(1) A shift target gear is selected by the selector 591.
(2) The target driving force is less than 0 (a negative value).
(3) The excess of the vehicle speed exceeds a predetermined speed (in this embodiment, 2 km / h).
(4) In the case of a deceleration operation (COAST operation), the actual acceleration exceeds the lower limit value of the target acceleration.
By setting a predetermined speed as a parameter in the condition (2), it is possible to adjust the excess amount of the vehicle speed at which the downhill road control is started. Further, the downhill road control is not performed in a deceleration operation (COAST operation) on an uphill slope (uphill slope). However, simply adjusting the target acceleration starts downhill road control at low vehicle speeds, and fuel is not cut at high vehicle speeds. Therefore, acceleration is determined in condition (4) so that downhill road control is not started by a deceleration operation on an ascending slope.
If any or all of the above conditions are not satisfied, 1 is output to the OFF timer 594 via the logic gate 593.

The ON timer 595 outputs the input value to the descending slope control flag selector 596 as an ON signal. The OFF timer 594 outputs the input value to the descending slope control flag selector 596 as an OFF signal. The descending slope control flag selector 596 resets the descending slope control flag when the OFF signal changes from 0 to 1, and outputs the constant speed travel target gear as the target gear. Further, when the ON signal changes from 0 to 1, the descending slope control flag selector 596 holds the descending slope control flag and outputs the shift target gear as the target gear.

According to the present embodiment, an appropriate target gear stage can be selected and output by the arbitration unit 59, and downhill road control is performed only when a downhill road that satisfies a condition is necessary, and a shift target gear stage is selected. be able to.

This application is based on a Japanese patent application filed on June 1, 2017 (Japanese Patent Application No. 2017-109116), the contents of which are incorporated herein by reference.

DESCRIPTION OF SYMBOLS 1 Traveling control apparatus 10 Target vehicle speed calculating part 20 Target driving force calculating part (FF)
30 Target driving force calculator (FB)
50

gear output units

51, 551, 561 target

output calculation units

52, 552, 562 shift determination unit 55 constant speed traveling gear output unit 56 transmission gear output unit 58 timer 59 arbitration unit 90 vehicle 91 transmission (automatic transmission)
553, 563

Downshift determination unit

554, 564 Upshift determination unit

Claims

A travel control device that performs constant speed travel control for traveling a vehicle at a target vehicle speed and shift control for performing an appropriate shift according to a travel state,
A target vehicle speed calculation unit for calculating the target vehicle speed;
A target driving force calculator for calculating a target driving force for traveling at the target vehicle speed;
A target output calculator for calculating a target output based on the target vehicle speed and the target driving force;
A constant speed traveling gear output unit that outputs a gear stage that causes the vehicle to travel at the target vehicle speed based on the target output as a constant speed traveling target gear stage;
A transmission gear output unit that is installed in parallel with the constant speed traveling gear output unit and outputs a shift target gear stage based on the target output;
An arbitration unit that arbitrates between the constant speed travel target gear stage and the shift target gear stage and outputs the target gear stage to the automatic transmission;
With
The shift gear output unit is a downshift that is an engine brake output when the current gear of the automatic transmission is shifted down by one stage, calculated based on the target output, engine brake torque, and engine speed. A shift down determination unit that determines whether or not a shift down is necessary based on a threshold value;
When the target output falls below the shift-down threshold value and it is determined that a shift-down is necessary, a shift-down control is performed to set the shift target gear to a value shifted down by one step from the current gear.
Travel control device.
The travel control device according to claim 1, wherein the target output calculation unit multiplies the calculated target output by a predetermined coefficient so as to reduce the target output.
The transmission gear output unit includes an engine output generated by fuel, the engine brake output at the current gear stage of the automatic transmission, and the engine brake output when the current gear stage is shifted up by one stage. A shift-up determination unit that determines whether or not a shift-up is necessary based on a shift-up threshold that is a deviation;
When it is determined that the engine output generated by the fuel exceeds the shift-up threshold value and needs to be shifted up, the shift-up target gear stage is set to a value shifted up by one stage from the current gear stage. The travel control device according to claim 1 or 2, wherein:
The travel control device according to claim 3, wherein the engine output generated by the fuel is multiplied by a predetermined coefficient so as to increase the engine output generated by the fuel.
The upshift determination unit determines that no upshift is required when the engine speed after shifting the shift target gear stage by one stage from the current gear stage is below a lower limit value of the engine speed. The travel control device according to claim 3 or 4, wherein:
The downshift determination unit determines that a downshift is not required when the engine speed after the shift target gear stage is shifted down by one stage from the current gear stage exceeds an upper limit value of the engine speed. The travel control device according to any one of claims 1 to 5.
The shift gear output unit includes a timer that outputs an input value with a predetermined time delay, and the timer uses the outputs of the downshift determination unit and the upshift determination unit as input values. The travel control device according to any one of the above.
The travel control according to any one of claims 1 to 7, wherein the arbitration unit compares the constant speed travel target gear stage with the shift target gear stage, and outputs the smaller one as the target gear stage. apparatus.
A vehicle comprising the travel control device according to any one of claims 1 to 8.
A traveling control method for performing constant speed traveling control for traveling a vehicle at a target vehicle speed and shift control for performing an appropriate shift according to a traveling state,
Calculating the target vehicle speed;
Calculating a target driving force for traveling at the target vehicle speed;
Calculating a target output based on the target vehicle speed and the target driving force;
A constant speed travel target gear output step for outputting a gear stage for driving the vehicle at the target vehicle speed based on the target output as a constant speed travel target gear stage;
A transmission gear output step that is performed in parallel with the constant speed traveling target gear output step, and that outputs a shift target gear stage based on the target output;
A step of arbitrating between the constant speed travel target gear stage and the shift target gear stage and outputting the target gear stage to an automatic transmission,
The shift gear output step is a downshift that is an engine brake output when the current gear stage of the automatic transmission calculated by the target output, engine brake torque, and engine speed is shifted down by one stage. And determining whether a downshift is necessary based on a threshold value,
When the target output exceeds the shift-down threshold value and it is determined that a shift-down is necessary, a travel control that performs shift-down control that sets the shift target gear to a value shifted down by one step from the current gear Method.
A traveling control program for performing constant speed traveling control for traveling a vehicle at a target vehicle speed and shift control for performing an appropriate shift according to a traveling state,
Calculating the target vehicle speed;
Calculating a target driving force for traveling at the target vehicle speed;
Calculating a target output based on the target vehicle speed and the target driving force;
A constant speed travel target gear output step for outputting a gear stage for driving the vehicle at the target vehicle speed based on the target output as a constant speed travel target gear stage;
A transmission gear output step that is performed in parallel with the constant speed travel target gear output step, and that outputs a shift target gear stage based on the target output;
And mediating between the constant speed travel target gear stage and the shift target gear stage and outputting the target gear stage to the automatic transmission,
The shift gear output step is a downshift that is an engine brake output when the current gear of the automatic transmission is shifted down by one step, calculated based on the target output, engine brake torque, and engine speed. And determining whether a downshift is necessary based on a threshold value,
When the target output exceeds the shift-down threshold value and it is determined that a shift-down is necessary, a travel control that performs shift-down control that sets the shift target gear to a value shifted down by one step from the current gear program.