JP2020133754A - Automatic transmission controller - Google Patents

Abstract

To provide an automatic transmission controller capable of executing downshift according to a travel state of a vehicle while reducing unintentional upshift for a driver.SOLUTION: When an inter-vehicle distance sensor (27) detects that an inter-vehicle distance between a preceding vehicle and a vehicle (1) has suddenly decreased (Yes in S103), and a target gear stage is a gear stage corresponding to upshift due to decrease in accelerator opening (Yes in S104), a transmission control unit (30) changes the target gear stage to a gear stage corresponding to downshift (S107) when a gradient sensor (25) detects that the vehicle (1) is traveling on an uphill road (Yes in S105), and changes the target gear stage to a stage to maintain a current gear stage (S106) when it is not detected that the vehicle is traveling on the uphill road (No in S105).SELECTED DRAWING: Figure 2

Description

The present invention relates to an automatic transmission control device.

Vehicle automatic transmissions include the so-called torque converter AT (Automatic transmission), which uses a torque converter as the joint between the drive source and the transmission mechanism, and the so-called AMT (Automated Manual), which automatically engages and disengages the clutch. Transmission).

The timing of switching the transmission gear of an automatic transmission generally takes into consideration a shift map based on the vehicle speed and the amount of depression of the accelerator pedal (accelerator opening) and the running condition of the vehicle (road gradient, vehicle weight, etc.). It is determined.

For example, Patent Document 1 describes a normal shift in a vehicle capable of low-speed cruise control that maintains an inter-vehicle distance that maintains a vehicle speed at a target speed in a predetermined low-speed region and maintains a constant inter-vehicle distance between the own vehicle and a preceding vehicle. In addition to the map, a configuration having an auxiliary upshift map used during the low-speed cruise control is disclosed. In the auxiliary upshift map, the shift line for upshifting has a wider range of vehicle speed parameters than the normal shift map, and by using the auxiliary upshift map during low-speed cruise control, it follows the start of the preceding vehicle. We are trying to reduce unnecessary shift-ups (busy shifts) when the vehicle starts.

Japanese Unexamined Patent Publication No. 2003-329123

In Patent Document 1, a plurality of shift maps according to the driving situation are prepared, and the drivability is improved by switching the shift map according to the driving situation. However, the driver depresses the accelerator pedal to accelerate. When the preceding vehicle approaches the own vehicle due to sudden deceleration, etc., or when another vehicle interrupts, the driver suddenly depresses the accelerator pedal, takes his foot off the accelerator pedal, etc. Emergency operation may be performed. In such a case, if the normal shift map is followed, the shift up will be executed.

Although the driver wants to decelerate in order to secure the distance from the preceding vehicle, when the shift up is executed, the engine brake becomes difficult to work and the deceleration becomes difficult. Especially when accelerating on an uphill road, if a sudden deceleration of the preceding vehicle or interruption of another vehicle occurs, it is desirable to shift down for subsequent acceleration.

The present invention has been made to solve such a problem, and an object of the present invention is to reduce an unintended shift-up by the driver and to execute a shift-down depending on the driving condition of the vehicle. The purpose is to provide an automatic shift control device.

The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following aspects or application examples.

The automatic shift control device according to this application example is an inter-vehicle distance detection unit capable of detecting the inter-vehicle distance between an automatic transmission capable of automatically shifting up and down and a preceding vehicle traveling in front of the own vehicle. It has an uphill road detection unit that can detect that the own vehicle is traveling on an uphill road, and a shift map that sets the target gear stage according to the accelerator opening and the vehicle speed, and at least based on the shift map. A shift control unit that sets a target gear and executes upshifts and downshifts of the automatic transmission is provided, and the shift control unit measures the distance between the preceding vehicle and the own vehicle by the inter-vehicle distance detection unit. When it is detected that the distance is within the predetermined distance, the reduction rate of the inter-vehicle distance is equal to or higher than the predetermined reduction rate, and the accelerator opening is lowered, the target gear stage becomes the gear stage corresponding to the shift-up. When the uphill road detection unit detects that the own vehicle is traveling on the uphill road, the target gear stage is changed to the gear stage corresponding to the downshift, and the uphill road detection unit causes the own vehicle to move uphill. When it is not detected that the vehicle is running, the target gear stage is changed to the current gear stage holding.

According to the present invention using the above means, it is possible to perform downshifting depending on the running state of the vehicle while reducing unintended upshifting by the driver.

It is a schematic block diagram which shows the drive system of the vehicle provided with the automatic shift control device in one Embodiment of this invention. It is a flowchart which shows the shift control routine executed by the shift control unit of the automatic shift control apparatus in one Embodiment of this invention. It is explanatory drawing in the case of changing the target gear stage from shift up to holding the current gear stage. It is explanatory drawing in the case of changing the target gear stage from shift up to shift down.

Hereinafter, an embodiment of an automatic transmission control device that embodies the present invention will be described.

FIG. 1 is a schematic configuration diagram showing a drive system of a vehicle provided in the automatic transmission control device of the present embodiment, and the configuration of the present embodiment will be described below based on the same diagram.

The vehicle 1 in the present embodiment is, for example, a truck, and a diesel engine (hereinafter referred to as an engine) 2 is mounted as a driving source for traveling. The input shaft 4a of the automatic transmission (hereinafter, simply referred to as a transmission) 4 is connected to the output shaft 2a of the engine 2 via the clutch device 3, and the rotation of the engine 2 is transmitted to the transmission 4 when the clutch device 3 is connected. It is supposed to be done. The transmission 4 is based on, for example, a manual transmission having 6 forward speeds and 1 reverse speed, and as described below, the shift operation and the engagement / disengagement operation of the clutch device 3 accompanying the shift are performed. It is an automated, so-called AMT (Automated Manual Transmission).

The clutch device 3 is configured as a friction type clutch that is connected to the flywheel 5 by pressing the clutch plate 6 with a pressure spring 7 while being engaged by separating the clutch plate 6 from the flywheel 5. An air cylinder 9 is connected to the clutch plate 6 via an outer lever 8, and an air tank 12 filled with compressed air is connected to the air cylinder 9 via an air passage 11 provided with a solenoid valve 10.

When the solenoid valve 10 is opened, compressed air is supplied from the air tank 12 to the air cylinder 9 via the air passage 11, and the air cylinder 9 operates to separate the clutch plate 6 from the flywheel 5 via the outer lever 8. The clutch device 3 is switched from the connected state to the disconnected state. On the other hand, when the solenoid valve 10 is closed, the air cylinder 9 does not operate due to the suspension of the supply of compressed air, so that the clutch plate 6 is pressed against the flywheel 5 by the pressure spring 7, whereby the clutch device 3 is released from the disengaged state. You can switch to the connected state. In this way, the air cylinder 9 operates in response to the opening and closing of the solenoid valve 10, and the clutch device 3 can be automatically engaged and disconnected.

The transmission 4 is provided with a gear shift unit 13 for switching gear stages, and although not shown, the gear shift unit 13 includes a plurality of air cylinders for operating shift forks corresponding to each gear stage in the transmission 4, and each. It has a built-in multiple solenoid valve that operates the air cylinder. The gear shift unit 13 is connected to the above-mentioned air tank 12 via an air passage 14, and compressed air from the air tank 12 is supplied to the corresponding air cylinder according to the opening and closing of each solenoid valve, and the air cylinder operates. When the corresponding shift fork is switched, the gear of the transmission 4 is geared according to the switching operation. In this way, the air cylinder operates according to the opening and closing of the solenoid valve of the gear shift unit 13, and the transmission 4 can be automatically changed. In the present embodiment, the clutch device 3 and the transmission 4 are mainly operated by air, but the operation method is not limited to this, and for example, hydraulic pressure may be used. Further, the clutch device 3 may be a wet multi-plate clutch.

Inside the vehicle 1, an ECU (control unit) including an input / output device (not shown), a storage device (ROM, RAM, etc.) used for storing control programs, control maps, etc., a central processing unit (CPU), a timer counter, and the like. ) 20 is installed, and comprehensively controls the engine 2, the clutch device 3, and the transmission 4.

On the input side of the ECU 20, for example, a lever position sensor 21 for detecting the switching position of the shift lever 15 provided in the driver's seat, an accelerator sensor 22 for detecting the operation amount (accelerator opening) of the accelerator pedal 16, and a brake pedal 17 Brake switch 23 for detecting the operation of, a gear sensor 24 for detecting the current gear stage of the transmission 4, a gradient sensor 25 (uphill road detection unit) for detecting the gradient of the road surface on which the vehicle 1 is traveling, and a transmission 4 Sensors such as a vehicle speed sensor 26 that detects the vehicle speed from the output shaft rotation speed and an inter-vehicle distance sensor 27 (inter-vehicle distance detection unit) that measures the inter-vehicle distance with the preceding vehicle are connected to the output shaft 4b. The inter-vehicle distance sensor 27 is, for example, a laser radar or a millimeter-wave radar. The gradient sensor 25 is not limited to directly detecting the gradient of the road surface, and may be calculated from the relationship between the rate of change in the vehicle speed of the vehicle 1 and the fuel injection amount (or engine output).

Further, the solenoid valve 10 of the clutch device 3 and the solenoid valves of the gear shift unit 13 are connected to the output side of the ECU 20, and the fuel injection valve of the engine 2 and the like are connected, although not shown. .. It should be noted that, instead of being comprehensively controlled by a single ECU 20 in this way, for example, an ECU dedicated to engine control may be provided separately from the ECU 20.

Then, for example, the ECU 20 calculates the fuel injection amount to each cylinder of the engine 2 from a map (not shown) based on the engine rotation speed and the accelerator opening degree detected by the accelerator sensor 22, and also determines the engine rotation speed and the fuel injection amount. Based on this, the fuel injection time is calculated from a map (not shown). Then, based on these calculated values, the engine 2 is operated while driving and controlling the fuel injection valve of each cylinder.

Further, the ECU 20 has a shift control unit 30 that executes an automatic shift mode when the D (drive) range is selected in the shift lever 15. The shift control unit 30 calculates the target gear stage based on the shift map in which the target gear stage is set according to the accelerator opening degree and the vehicle speed, and the traveling state of the vehicle 1 such as the road gradient and the vehicle weight. Then, while opening and closing the solenoid valve 10 of the clutch device 3 and engaging and disconnecting the clutch device 3 by the air cylinder 9, the predetermined solenoid valve of the gear shift unit 13 is opened and closed, and the corresponding shift fork is switched by the air cylinder. The gear is put into the target gear stage, whereby the vehicle is always driven with the appropriate gear stage.

The shift positions in which the shift lever 15 can be selected include an N (neutral) range in which the gear of the transmission 4 is in neutral, a D (drive) range selected when traveling forward, and an R (reverse) range selected when traveling backward. There is an M (manual) range in which the gear stage can be manually shifted up or down.

Further, the ECU 20 may have an auto cruise control unit. The auto-cruise control unit can carry out auto-cruise control that controls the engine 2 and the transmission 4 so as to maintain the target vehicle speed set by the driver.

Then, when there is a preceding vehicle in front of the own vehicle while traveling based on the auto cruise control, the auto cruise control unit accelerates or decelerates so as to keep the inter-vehicle distance from the preceding vehicle within a certain range. Auto cruise control is also feasible.

In the vehicle 1 configured in this way, the shift control unit 30 of the ECU 20 includes an inter-vehicle distance sensor 27 used for inter-vehicle distance maintenance auto-cruise control and a gradient sensor 25 capable of detecting that the vehicle 1 is traveling on an uphill road. It is possible to execute shift control that limits unnecessary shift-ups by using.

Specifically, the shift control unit 30 detects that the inter-vehicle distance between the preceding vehicle and the own vehicle has been shortened within a predetermined distance by the inter-vehicle distance sensor 27, and the reduction rate of the inter-vehicle distance is equal to or higher than the predetermined reduction rate. Detects a certain case, that is, a case where the preceding vehicle suddenly approaches or a case where another vehicle interrupts in front of the own vehicle. On that basis, the shift control unit 30 indicates that the vehicle 1 is traveling on an uphill road by the gradient sensor 25 when the target gear stage becomes the gear stage corresponding to the shift up due to the decrease in the accelerator opening. When it is detected, the target gear is changed to the gear corresponding to downshift, and when it is not detected that the vehicle 1 is traveling on an uphill road, the target gear is changed to hold the current gear.

For details, referring to FIGS. 2 to 4, FIG. 2 shows a flowchart showing a shift control routine executed by the shift control unit 30 of the ECU 20, and FIG. 3 shows the target gear stage changed from shift-up to holding the current gear stage. An explanatory diagram in the case of changing the target gear stage from upshifting to downshifting is shown in FIG. 4, respectively. Hereinafter, the shift control executed by the shift control unit 30 will be described in detail with reference to FIGS. 3 and 4 in the middle according to the flowchart of FIG.

First, in step S101 of FIG. 2, the shift control unit 30 determines whether or not the vehicle is traveling in the automatic shift mode. Specifically, the shift control unit 30 determines whether or not the shift lever 15 is in the D range position from the information from the lever position sensor 21. If the determination result is false (No), that is, in the auto cruise mode or the manual shift mode, the shift control unit 30 does not execute the shift control and returns the routine.

On the other hand, if the determination result is true (Yes), that is, if the shift lever 15 is in the D range position, the process proceeds to step S102.

In step S102, the shift control unit 30 calculates the target gear stage based on the shift map and the traveling state (road gradient, vehicle weight) of the vehicle 1.

In the following step S103, the shift control unit 30 determines whether or not the preceding vehicle suddenly approaches or is interrupted. Specifically, the shift control unit 30 determines whether or not the inter-vehicle distance detected by the inter-vehicle distance sensor 27 is equal to or less than a predetermined distance and the reduction rate of the inter-vehicle distance is equal to or greater than the predetermined reduction rate. The predetermined distance and the predetermined reduction rate are set to the reduction rate of the inter-vehicle distance and the inter-vehicle distance that require deceleration of the vehicle 1. The predetermined distance and the predetermined reduction rate are not limited to fixed values, and more appropriate control is possible by using variable values that fluctuate according to the vehicle speed.

When the determination result in step S103 is true (Yes), that is, when the inter-vehicle distance is suddenly shortened, for example, when the preceding vehicle suddenly approaches, or when another vehicle interrupts in front of the vehicle 1. Since the inter-vehicle distance is equal to or less than the predetermined distance and the reduction rate of the inter-vehicle distance is equal to or greater than the predetermined reduction rate, the process proceeds to step S104.

In step S104, the shift control unit 30 determines whether or not the target gear stage becomes the upper gear stage (becomes the gear stage corresponding to the shift up) due to the decrease in the accelerator opening degree in the shift map. That is, when the driver loosens the accelerator pedal 16 or releases the accelerator pedal due to the approach of the preceding vehicle or the interruption of another vehicle, the accelerator opening exceeds the shift-up line on the shift map and is in the upper gear. When entering the area of the stage, the determination result is true (Yes), and the process proceeds to the next step S105.

In step S105, the shift control unit 30 determines whether or not the vehicle 1 is currently traveling on an uphill road. Specifically, it is determined whether or not the road surface gradient detected by the gradient sensor 25 is equal to or greater than a predetermined gradient. If the determination result is false (No), that is, if the vehicle is traveling on a flat road or a downhill road, the process proceeds to step S106.

In step S106, the shift control unit 30 does not set the gear stage corresponding to the shift up as the target gear stage, but changes the target gear stage so as to hold the current gear stage. Therefore, the shift control unit 30 does not perform a shift operation on the transmission 4, and the gear stage of the transmission 4 is held at the current gear stage.

Here, the transition of the shift map in the case of step S106 will be described with reference to FIG. In the shift map of FIG. 3, a solid line indicates an upshift line, and a dotted line indicates a downshift line. FIG. 3 shows a case where the driver takes his / her foot off the accelerator pedal while the vehicle 1 is traveling at a vehicle speed of 40 km / h, an accelerator opening of 80%, and a gear of 4th speed.

When the driver takes his foot off the accelerator pedal, the driving point on the shift map changes from point A1 at a vehicle speed of 40 km / h and an accelerator opening of 80% to point A2 with an accelerator opening of 0%. At this time, since the shift-up line (solid line 4 → 5) of the shift map is crossed, the target gear stage is shifted up to the 5th speed according to the shift map, but the shift control unit 30 is the target gear stage. Is held in the 4th gear, which is the current gear stage. After that, the vehicle speed drops, the driving point moves from A2 point to A3 point, and after crossing the shift down line from 5th speed to 4th speed (dotted line 4 ← 5), the shift up restriction is released and the original shift Shift to shift control based on the map.

On the other hand, if the determination result in step S105 is true (Yes), that is, if the vehicle 1 is traveling on an uphill road, the process proceeds to step S107.

In step S107, the shift control unit 30 changes the target gear stage calculated in step S102 from the gear stage corresponding to upshifting to the gear stage corresponding to downshifting.

Then, in step S108, the shift control unit 30 shifts down the current gear stage so as to be the target gear stage corresponding to the shift down with respect to the transmission 4, and returns the routine.

Here, the transition of the shift map in the case of step S108 will be described with reference to FIG. The shift map of FIG. 4 shows a case where the driver takes his / her foot off the accelerator pedal while the vehicle 1 is traveling on an uphill road at a vehicle speed of 40 km / h, an accelerator opening of 100%, and a gear of 4th speed.

When the driver takes his foot off the accelerator pedal, the driving points on the shift map change from point B1 at a vehicle speed of 40 km / h and an accelerator opening of 100% to point B2 with an accelerator opening of 0%. At this time, since the shift-up line (solid line 4 → 5) of the shift map is crossed, the target gear stage is shifted up to the 5th speed according to the shift map, but the shift control unit 30 is the target gear stage. Is changed to 3rd gear, which is one step down from the current gear. After that, as the vehicle speed decreased, the driving point moved from B2 point to B3 point and maintained the 3rd speed even after crossing the downshift line (dotted line 4 ← 5) from the 5th speed to the 4th speed. After that, in order to re-accelerate on the uphill road, the accelerator is fully opened (accelerator opening 100%), the driving point moves from B3 point to B4 point, and the downshift line from 4th gear to 3rd gear (dotted line 3 ← 4) After crossing, the shift-up restriction is released and shift control is performed based on the original shift map.

Further, when the determination result in step S103 or step S104 is false (No), that is, when the distance between the vehicle and the preceding vehicle is larger than the predetermined distance, or when the accelerator opening degree decreases, the target gear stage is the upper gear. If the gear does not become a gear (the gear does not correspond to the shift up), the process proceeds to step S109.

In step S109, the shift control unit 30 determines whether or not the target gear stage is the same as the current gear stage. If the determination result is false (No), that is, if shift-up or shift-down is necessary, the process proceeds to step S108 to shift to the target gear.

On the other hand, if the determination result in step S109 is true (Yes), the process proceeds to step S110, and the shift control unit 30 holds the current gear stage and returns the routine.

As described above, in the automatic shift control device of the present embodiment, the inter-vehicle distance sensor 27 used in the auto-cruise control in the shift control is used to detect the sudden deceleration of the preceding vehicle and the interruption of another vehicle, and in response to this When the accelerator opening decreases and the target gear becomes a gear that corresponds to upshifting, upshifting is restricted, the current gear is held if it is not an uphill road, and downshifting if it is an uphill road. I do.

As a result, it is possible to limit the shift-up against the driver's intention to decelerate and realize reliable deceleration. Especially on uphill roads, by performing a downshift, smooth acceleration can be achieved thereafter. Further, by using the inter-vehicle distance sensor 27 used in auto-cruise control, the present invention can be easily applied to a vehicle capable of auto-cruise control without the need for additional parts or the like.

As described above, according to the dynamic shift control device according to the present embodiment, it is possible to execute downshifting depending on the traveling state of the vehicle while reducing upshifting unintentionally by the driver.

The description of the embodiment of the vehicle-to-vehicle distance control device according to the present invention is completed above, but the aspect of the present invention is not limited to this embodiment.

In the above embodiment, the vehicle 1 is used as a truck, but the vehicle to which the present invention can be applied is not limited to this, and the vehicle can also be applied to a passenger car.

Further, in the above embodiment, the engine 2 is a diesel engine, but the engine is not limited to this, and may be, for example, a gasoline engine. Further, the drive source is not limited to the engine and may be a motor. Further, in the above embodiment, the transmission has six forward gears and one reverse gear, but the configuration of the transmission is not limited to this.

Further, although the drive system of the vehicle of the above embodiment adopts AMT, the drive system to which the present invention can be applied is not limited to this, and for example, the engine is connected to the automatic transmission via a torque converter. It may be a configured configuration.

1 Vehicle 2 Engine 4 Transmission 16 Accelerator pedal 20 ECU
22 Accelerator sensor 24 Gear stage sensor 25 Gradient sensor (Uphill road detection unit)
26 Vehicle speed sensor 27 Inter-vehicle distance sensor (inter-vehicle distance detector)
30 Shift control unit

Claims (1)

An automatic transmission that can automatically shift up and down gears,
An inter-vehicle distance detection unit that can detect the inter-vehicle distance with the preceding vehicle traveling in front of the own vehicle,
An uphill road detection unit that can detect that the vehicle is traveling on an uphill road,
It has a shift map that sets the target gear stage according to the accelerator opening and the vehicle speed, and at least the target gear stage is set based on the shift map, and the shift control that executes the shift up and down of the automatic transmission. Department and preparation,
In the gear shift control unit, the inter-vehicle distance detection unit detects that the inter-vehicle distance between the preceding vehicle and the own vehicle is within a predetermined distance, and the reduction rate of the inter-vehicle distance is equal to or greater than the predetermined reduction rate, and the accelerator opening degree. When the target gear stage becomes the gear stage corresponding to the upshift due to the decrease in, the target gear stage is shifted when the uphill road detection unit detects that the own vehicle is traveling on the uphill road. An automatic transmission control device that changes to a gear that corresponds to down, and changes the target gear to hold the current gear when the uphill detection unit does not detect that the vehicle is traveling on an uphill.

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