JP4409207B2 - Transmission control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is used for an automatic transmission of an automobile. The present invention relates to an improvement in downshift control by an automatic transmission. The present invention takes in the amount of depression of the brake pedal operated by the driver as one of the input information, and uses this as information for instructing the vehicle to decelerate when the brake pedal is depressed. And a control logic for executing downshift control of the automatic transmission.
[0002]
Here, the “automatic transmission device” refers to a gear that is set stepwise by arithmetic control using information relating to engine rotation and information relating to the accelerator opening as input information, even if the driver does not directly change the transmission. A device that selectively controls the combination of gears. This "automatic transmission" is a transmission that automatically executes selection of a transmission gear according to input information, and is equipped with a transmission lever for selecting a transmission gear by operation, or opens and closes a clutch by operation. So-called semi-automatic, which is equipped with a clutch pedal for performing the operation, interrupting the control automatically executed by the control device, and performing a shift operation by the operation The type of transmission is also included in its category.
[0003]
[Prior art]
Automatic transmissions are also widely used in commercial vehicles such as trucks and buses. In commercial vehicles, the vehicle weight varies greatly depending on the cargo loading state or the number of passengers, so it is practically difficult to design the automatic shift operation to satisfy the driver under all conditions. . In particular, many commercial vehicle drivers are skilled in driving operations, and do not rely on automatic transmission control for all gear shifting operations. -A device that can perform a fine driving operation by operating a pedal is preferred. For this reason, even in a device that is configured so that the clutch is automatically connected / disconnected by hydraulic control in accordance with the speed change operation, a clutch pedal is provided to perform automatic interrupt control for the driver. Devices configured to be able to disengage the clutch by operation or to be controlled to a half-clutch state have become widespread.
[0004]
In such devices, most of the speed change levers are provided with N (neutral), D (drive), and R (reverse) ranges, and in addition, UP and DOWN instruction operations can be performed. An example of the shift state of the shift lever is shown at the left end of FIG. 1 which is a reference drawing of the embodiment device of the present invention described later. That is, when the speed change lever is set to the D (drive) position, the optimum gear ratio is selected and set from the information on the engine rotation and the accelerator pedal opening at that time by automatic control of the speed change control device. The
[0005]
In a vehicle equipped with such a shift control device, in a steady running state, the shift lever is set to the D (drive) position, and the selection of the shift gear is automatically executed. That is, the vehicle travels by selecting and setting an appropriate transmission gear by calculation according to the vehicle speed and the engine load. At this time, in many control devices, the control logic is selected so that the fuel efficiency of the engine is the best, corresponding to the accelerator opening at that time. At this time, when the accelerator pedal is released and the brake pedal is stepped on, the vehicle speed may decrease, so that the engine rotation speed may decrease and the transmission gear may be changed. However, this does not directly change the speed change gear by operating the brake pedal.
[0006]
Further, in the conventional apparatus, in a vehicle equipped with an ABS (anti-lock brake system), there is known an apparatus for temporarily prohibiting the change of the transmission gear during the operation of the ABS. This is because it is safe to keep the axle connected to the engine rotation shaft when the vehicle is in a sudden braking state where the ABS operates. Such temporary prohibition control is in principle unrelated to the logic of gear selection control of the automatic transmission.
[0007]
Some vehicles sold in recent years are configured such that an automatic transmission is provided with a manual mode and can be changed by an operation. This is a shift lever provided with an H (hold) position. When the gearshift lever is set to the H (hold) position, automatic gear selection is prohibited until manual mode is released from that point onward, and the driver operates the gearshift lever UP or DOWN. You will follow the instructions. That is, when the driver operates the shift lever to the UP position or the DOWN position without stepping on the clutch pedal, the shift control device automatically reduces the fuel supply amount to the engine, disengages the clutch, and sets the shift gear to the shift lever instruction. Accordingly, the clutch is automatically engaged when the transmission gear is changed. Even if the amount of depression of the accelerator pedal does not change over the period during which this speed change operation is being performed, the control device performs control so that the amount of fuel supplied to the engine is appropriately adjusted in accordance with the engagement / disengagement of the clutch. . Furthermore, when the driver operates the shift lever twice at short intervals at the DOWN position, the shift gear is shifted down by two steps while the clutch is disengaged. Such an operation is also possible.
[0008]
Such a manual mode is useful for downshifting when actually traveling on the road. That is, in a state where the vehicle is constantly accelerated, if the automatic mode is set, the transmission gear is automatically and rationally selected by the driver pressing the accelerator pedal. However, the control for enabling the engine brake by downshifting is not always automatically performed properly. By enabling selection control by the driver as described above, the automatic control of the transmission gear is complemented especially when the vehicle speed is reduced.
[0009]
Japanese Patent Application Laid-Open No. H10-228707 discloses that the amount of depression of a brake pedal is used as input information for an automatic transmission. In this patent document 1, there is a description in FIG. 5 and FIG. 9 and the related description that the depression angle of the brake pedal by the driver is used for speed control as a control function.
[0010]
[Patent Document 1]
Japanese Patent Laid-Open No. 5-77762
[Problems to be solved by the invention]
As described above, in the conventional device, in principle, the amount of depression of the accelerator pedal is used as the input information given by the driver to control the automatic transmission. This is sufficient as input information for accelerating the vehicle, but this is not always sufficient as information for decelerating the vehicle. The brake pedal operation information by the driver is information that the driver is trying to decelerate the vehicle, and the inventor of the present application considers whether it can be actively used for controlling the automatic transmission. did.
[0012]
However, if the brake is stepped on while the automatic transmission selects the n-th gear, it does not mean that this can be immediately shifted down to the (n-1) -th stage as a driver's intention to decelerate. . For example, when the driver is about to stop the vehicle suddenly, it is not reasonable to automatically disengage the clutch and change the transmission.
[0013]
In the present invention, instead of selecting a transmission gear according to the vehicle speed (or engine speed) and the amount of depression of the accelerator pedal, the operation information of the brake pedal by the driver is input and this is appropriately shifted. An object of the present invention is to provide an automatic transmission used as down information. An object of this invention is to provide the automatic transmission which can perform downshift control rationally.
[0014]
[Means for Solving the Problems]
The present invention provides a control map for executing a downshift of the brake pedal depression amount (β) with respect to the engine speed (ω) in order to use the brake operation information as input information for the automatic transmission. There is the biggest feature to use.
[0015]
That is, according to the present invention, in a transmission control device that selectively controls a transmission gear using information including the engine speed and the accelerator opening as input information, the brake pedal depression amount is taken as one of the input information, and the engine speed ( Control logic for performing a downshift with reference to a map of the brake pedal depression amount (β) with respect to ω) is provided.
[0016]
The control logic can be set to be effective when the accelerator pedal is released. The control logic can be set to be effective when the transmission lever position is at the D position.
[0017]
The map uses engine speed (ω) and brake pedal depression amount (β) as two-dimensional input information, and limit curves of two transmission gears are set on the two-dimensional coordinates (ω, β). It is desirable that the two-dimensional map for downshifting the transmission when the dimension input information exceeds the limit curve on the coordinates from a state where the engine speed (ω) is large to a small state.
[0018]
In an example of the map, when the engine speed (ω) is taken on the horizontal axis and the brake pedal depression amount (β) is taken on the vertical axis, the limit curve has points A (ω ₁ , β ₁ ), points A curve passing through B (ω ₂ , β ₂ ) and point C (ω ₃ , β ₃ ) can be obtained.
However, ω ₁ is the lowest engine speed ω ₂ that can be driven is the medium engine speed ω ₃ is the engine idling speed β ₁ is the amount that the brake pedal is not actually depressed (β ₁ ≒ 0)
β ₂ is the intermediate depression amount of the brake pedal β ₃ is the maximum depression amount of the brake pedal. This will be described in detail later with reference to FIG.
[0019]
As in the conventional device, the device of the present invention is basically a map that takes the accelerator opening (α%) with respect to the engine speed (ω rpm) as the logic for selectively controlling the transmission gear of the transmission control device. Above, a map depicting a curve for performing the shift down is used. In accordance with the input information, when the accelerator opening increases with respect to the engine speed and exceeds the curve, shift down control is executed (see FIG. 3 as an example). This control logic is practically unavailable in areas where the accelerator pedal is released. When the brake pedal is depressed at this time, the apparatus of the present invention sets a map that takes the brake pedal depression amount (β%) with respect to the engine rotation speed (or vehicle speed) (ω rpm) as control logic. Shift down control is executed using.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
First, an outline of an automatic transmission apparatus embodying the present invention will be described with reference to FIG. This example relates to the semi-automatic transmission in the above description.
[0021]
The rotational output of the engine 1 is transmitted to the transmission 3 via the clutch 2, and is further transmitted from the propeller shaft 4 to an unillustrated axle. The fuel injection pump 5 of the engine 1 is controlled by an engine ECU 6 constituted by a program control circuit. The clutch 2 of this device is a so-called mechanical clutch, and its connection / disconnection operation is controlled by a clutch / actuator 37. In this example, the transmission 3 is a mechanical type having seven forward speeds and one reverse speed, and is controlled by the shift unit 7 in the XY directions. The clutch actuator 37 and the shift unit 7 are controlled by the air pressure supplied from the air tank 8. The air pressure supplied to the clutch actuator 37 is controlled by the clutch control valve 9. The shift unit 7 incorporates control valves in the X direction (shift) and the Y direction (select) inside, and air pressure is supplied to the shift cylinder and the select cylinder through these control valves. The control valve incorporated in the clutch control valve 9 and the shift unit 7 is electrically controlled by a transmission control device 10 configured by a program control circuit. The present invention is implemented in the transmission control device 10 and is implemented by adding control logic of the transmission control device 10.
[0022]
In addition to being controlled by the clutch / actuator 37, the clutch 2 can be directly mechanically controlled via a hydraulic system 13 by a hydraulic pump 12 driven by a clutch pedal 11. That is, when the clutch 2 is in the connected state, the driver can perform connection / disconnection control including the half clutch by stepping on the clutch pedal 11 in the driver's seat. Using the clutch control by the clutch pedal 11, the driver can perform the control by the own clutch operation without depending on the control of the automatic clutch when the vehicle starts from the stop state. The clutch disengagement operation by the clutch pedal 11 has priority over the clutch control by the transmission control device 10. In general, the clutch operation by the clutch pedal 11 is often used only when starting, that is, only when starting the vehicle from a state where the vehicle speed is zero. As explained above, the driver of this type of commercial heavy vehicle is generally a professional driver and does not feel annoying to control the clutch engagement state with his / her left foot when starting. Rather, this device is well-received by the driver because it can perform delicate clutch control in the low gear at the start as desired and smoothly start. Further, by performing clutch control with the left foot of the driver at the time of starting, fuel consumption can be saved and the amount of exhaust gas can be reduced.
[0023]
Returning to the description of the configuration shown in FIG. 1, in conjunction with the operation of the clutch pedal 11, the clutch switch 14 for detecting that the clutch pedal 11 is in the released state, and that the clutch pedal 11 has been depressed. A clutch switch 15 is provided to detect this, and these detection outputs are taken into the transmission control device 10. The accelerator pedal 16 is provided with an accelerator position sensor 17 whose output is taken into the engine ECU 6.
[0024]
The state of the transmission lever 18 provided in the driver's seat is taken into the transmission control device 10. As shown at the left end of FIG. 1, the speed change lever 18 has four positions, N range (neutral position), D range (drive position), H range (hold position), and R range (reverse position). Can be set. Here, the H range is an operation position for temporarily prohibiting the shift control of the transmission control device 10 by the driver's operation and for setting the manual mode described above.
[0025]
When the speed change lever 18 is set to the D range at the time of start, all gear selection settings after start are automatically executed under the control of the transmission control device 10. For example, if the shift lever 18 is shifted to the D range and the vehicle is started, the second speed is selected and set when the vehicle speed is zero, and the shift gear is automatically shifted up according to the acceleration state after the vehicle starts. Go. Each time the transmission gear is changed, the clutch 2 is repeatedly disconnected and connected under the control of the transmission control device 10, and the flow rate of fuel supplied to the engine 1 is increased or decreased in synchronization therewith.
[0026]
Further, when the shift lever 18 is in the H (hold) range, by operating the lever up or down, the driver gives an exceptional upshift or downshift to automatic gear selection. can do. This operation can be shifted up or down by two stages by swinging up or down twice. Also at this time, the clutch 3 is automatically disconnected, a gear shift is executed, the clutch 3 is controlled to be automatically connected, and the fuel flow rate is automatically adjusted.
[0027]
The vehicle speed information is taken into the transmission control device 10 from a vehicle speed sensor 35 that detects the rotation of the propeller shaft 4. In order to detect the state of the transmission 3, the transmission 3 is provided with a countershaft rotation sensor 36, and this output information is taken into the transmission control device 10. The transmission control device 10 is connected to the engine ECU 6 via a communication bus 34. The engine ECU 6 is also connected to the monitor interface 20 and the display 21 arranged in the driver's seat via the communication bus 34.
[0028]
The embodiment of the present invention is characterized in that it takes in information on the depression amount of the brake pedal 22. The detection output of the stroke sensor 23 interlocked with the stroke of the brake pedal 22 is connected to the transmission control device 10. The pneumatic system of the brake pressure cylinder 24 that is linked to the brake pedal 22 is connected to the brake control system as is well known. The configuration of the brake control system is a well-known technique and is not directly related to the present invention. Therefore, the description in this drawing is omitted and the description thereof is also omitted. Practically, it is convenient to obtain the depression amount information of the brake pedal 22 from a brake control circuit (brake ECU) (not shown) via a communication bus.
[0029]
The state information of the pressure sensor 25 of the air tank 8 is taken into the transmission control device 10. In this configuration, when the air pressure of the air tank 8 is lowered, a control signal is sent to the emergency valve 26 so that the emergency air pressure 27 is used, thereby improving the reliability of the automatic transmission. Is. In addition, the transmission control device 10 includes PTO (Power Take Off) device status information 28, retarder device status information 29, brake control system status information 30, exhaust brake control system status information 31, brake pressure. Information 33 and the like are captured.
[0030]
An operation switch 38 disposed in the driver's seat is connected to the transmission control device 10, and an alarm buzzer 39 disposed in the driver's seat is connected to the transmission control device 10. The transmission control device 10 receives an operation input from the emergency operation end 40 disposed in the driver's seat. The operation switch 38, the alarm buzzer 39, and the emergency operation end 40 are used when the operation of the transmission control device 10 is in an abnormal state. These are important elements for preventing a road breakdown of the vehicle, but since their configuration and operation are not directly related to the present invention, further detailed explanation is omitted here.
[0031]
Information on the engine load factor is taken into the transmission control device 10 from the engine ECU 6. The engine load factor is defined as the ratio of the current engine output torque to the maximum engine output torque that can be output depending on the current rotational speed of the engine. This calculation is performed by the engine ECU 6 and is also taken into the transmission control device 10 via the communication bus 34 and used as auxiliary information for transmission gear selection control.
[0032]
Here, the shift control of the transmission control device 10 will be described. The transmission control device 10 includes information on the engine rotational speed (ω) to be input and an accelerator opening (appearing in the output of the position sensor 17 of the accelerator pedal 16). Software that selects the optimal gear is set according to the information of α). When the accelerator pedal 16 is depressed greatly during the steady running state, the downshift gear is automatically selected and set. FIG. 3 shows an example of the control map. This control map performs shift-down control from 5th gear to 4th gear, but from 1st gear to top gear (up to 7th gear in this example), for controlling upshift or downshift of each gear. A control map is set as software in the transmission control device 10.
[0033]
The feature of the present invention is that a control map for controlling the downshift is provided for the brake pedal depression amount (β) with respect to the engine rotation speed (ω) as illustrated in FIG. When the shift lever is in the D range, the accelerator pedal is released, and the accelerator opening is substantially zero, the shift down is executed using this control map.
[0034]
In the control map shown in FIG. 2, when the engine rotation speed (ω) is taken on the horizontal axis and the brake pedal depression amount (β) is taken on the vertical axis, the point A (ω ₁ , β ₁ ), Curves passing through point B (ω ₂ , β ₂ ) and point C (ω ₃ , β ₃ ) are drawn. Here, ω ₁ is the lowest rotational speed of the engine that can travel, and ω ₂ is the engine rotational speed of about medium speed. ω ₃ is the engine idling speed. Because of its nature
0 <ω ₃ <ω ₁ <ω ₂
It becomes. β ₁ is zero or an extremely small value of the brake pedal depression amount, β ₂ is a moderate value of the brake pedal depression amount, and β ₃ is a value at which the brake pedal is almost fully depressed. is there. That is,
0 <β ₁ <β ₂ <β ₃
It becomes. When the relationship between the engine rotation speed and the brake / depression amount moves from the right side to the left side of the curve passing through the points A, B, and C, the transmission is downshifted from the nth speed to the n-1th speed.
[0035]
In FIG. 2, while the vehicle is running at the operating point P ₁ and the transmission is set to n-speed, the brake pedal is gently depressed, the vehicle speed decreases, and the engine speed decreases accordingly. Shall. At this time, the operating point moves from P ₁ to P ₂ . This is because the operating point passes through the curve passing through points A, B, and C from right to left, and the transmission is downshifted from the nth speed to the n-1th speed.
[0036]
Further, it is assumed that the brake pedal is strongly depressed during traveling at the operating point P ₁ and the operating point moves from P ₁ to P ₃ . At this time, the line connecting the two operating points P ₁ and P ₂ is a substantially vertical straight line. That is, before the vehicle speed decreases due to the effect of the brake, the curve AB and the same BC are crossed. In this case, downshifting is not performed. The driver's intention is to stop the vehicle suddenly by sudden braking, and it is reasonable not to execute shift down / down of the transmission. Generally, it takes about 1/2 second of operation time to shift down a transmission. When the movement of the brake pedal is fast on this map, the shift down is not activated immediately when the operating point exceeds the curve, but the nth speed is maintained. In other words, it is preferable that the shift map be ignored when the change amount (% / sec) of the brake pedal is equal to or less than the specified value and equal to or more than the specified value.
[0037]
Furthermore, it is assumed that further time has elapsed from the state where the operating point is at P _3, and that the engine rotational speed has decreased and the operating point has reached P ₄ as the vehicle speed has decreased. That is, the vehicle speed is reduced while the brake pedal is depressed. It is assumed that the brake pedal is loosened when the vehicle speed becomes extremely small. That the operation point on this control map when moving from P ₄ to P _5, down-shifting of the transmission is performed to the n gear n-1 speed.
[0038]
Thus, the downshift control according to the driver's intention can be performed using the control map illustrated in FIG. Equipped with such a control map for shifting down from n-speed to n-1 speed, shifting down from n-1 speed to n-2 speed, shifting down from n-2 speed to n-3 speed, etc. By doing so, a reasonable downshift control of the automatic transmission can be executed.
[0039]
FIG. 4 shows a main part flowchart relating to the control of the embodiment apparatus of the present invention. That is, when the shift lever is in the D position, the accelerator pedal is released, and the brake pedal is depressed, the control map described in FIG. 2 is set according to the gear ratio selected at that time, and the shift down is performed. Determined. If this is the downshift position from the top of the control map, downshift is performed at that point.
[0040]
【The invention's effect】
According to the present invention, the operation information of the brake pedals by the driver can be used as input and appropriately used as downshift information. According to the present invention, it is possible to provide an automatic transmission that can reasonably perform downshift control.
[Brief description of the drawings]
FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention.
FIG. 2 is an example of a control map of the embodiment device of the present invention.
FIG. 3 is an example of a control map when an accelerator pedal is depressed.
FIG. 4 is a main part control flowchart of an apparatus according to an embodiment of the present invention;
[Explanation of symbols]
1 Engine 2 Clutch 3 Transmission 4 Propeller Shaft 5 Fuel Injection Pump 6 Engine ECU
7 Shift unit 8 Air tank 9 Clutch control valve 10 Transmission control device 11 Clutch pedal 12 Hydraulic pump 13 Hydraulic system 14 Clutch switch (upper end)
15 Clutch switch (lower end)
16 Accelerator pedal 17 Accelerator position sensor 18 Shift lever 19 Blinker switch 20 Monitor interface 21 Indicator 22 Brake pedal 23 Stroke sensor 24 Brake pressure cylinder 25 Pressure sensor 26 Emergency valve 27 Emergency air pressure 28 PTO device information 29 Retarder Information 30 Anti-lock brake device control information 31 Exhaust brake control system information 32 Brake state information 33 Brake pressure information 34 Communication bus 35 Vehicle speed sensor 36 Countershaft rotation sensor 37 Clutch actuator 38 Operation switch 39 Alarm buzzer 40 Emergency operation end

Claims (1)

In a transmission control device that selectively controls a transmission gear using information including the engine speed and the accelerator opening as input information,
A control logic for taking in the brake pedal depression amount as one of the input information and performing a downshift with reference to a map of the brake pedal depression amount with respect to the engine rotation speed ,
The map uses engine speed (ω) and brake pedal depression amount (β) as two-dimensional input information, and limit curves of two transmission gears are set on the two-dimensional coordinates (ω, β). A two-dimensional map for downshifting the transmission when the dimension input information exceeds the limit curve on the coordinates from a state where the engine speed (ω) is large to a small state;
The limit curve of the two-dimensional map is a curve that passes through a point A (ω ₁ , β ₁ ), a point B (ω ₂ , β ₂ ), and a point C (ω ₃ , β ₃ ). Machine control device.
Where ω ₁ is the minimum engine speed that can be driven
ω ₂ is medium engine speed
ω ₃ Is the engine idling speed
β ₁ is the amount that the brake pedal is not actually depressed
(Β ₁ ≒ 0)
β ₂ is a moderate amount of brake pedal depression
β ₃ is almost the maximum depression amount of the brake pedal
And

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