JP2010060010A - Control device for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an automatic transmission capable of maintaining the vehicle speed constant while suppressing fuel consumption and improving fuel economy regardless of the steepness of an inclination angle of a traveling downward slope. <P>SOLUTION: This control device for an automatic transmission is equipped with a friction fastening means (first clutch C1) for connecting and disconnecting power transmission between an engine Eg and a drive wheel K, and a downward slope constant speed travel control means D1 for performing constant speed travel control for maintaining the vehicle speed constant. An inclination angle detecting means (inclination angle sensor) 7 for detecting the inclination angle of the traveling road surface of a vehicle is provided. The downward slope constant speed travel control means D1 includes a semi-neutral travel control part D3 for executing sliding fastening control of the friction fastening means (first clutch C1) while maintaining the speed change ratio when the vehicle is traveling a gentle downward slope DH1 in which an inclination angle detection value is less than a set value X, and a shift travel control part D4 for executing speed change control for maintaining the vehicle speed constant when the vehicle is traveling a steep downward slope DH2 in which the inclination angle detection value is the set value X or more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for an automatic transmission that performs constant speed traveling control that keeps the vehicle speed constant during downhill traveling.

  2. Description of the Related Art Conventionally, there is known an automatic transmission control device that performs neutral traveling control when performing coasting traveling when decelerating or descending a slope with the accelerator released, for the purpose of improving fuel efficiency during traveling (for example, Patent Documents). 1).

Conventionally, the control of an automatic transmission that aims to travel downhill at a constant speed, shifts down when the vehicle speed when traveling downhill exceeds a set value, and shifts up when the vehicle speed falls below the set value. An apparatus is also known (see, for example, Patent Document 2).
Japanese Examined Patent Publication No. 61-57214 JP-A-62-99221

  However, in the conventional automatic transmission control device that performs neutral travel control, the engine rotates idle during the neutral travel control, resulting in an insufficient oil pump discharge capacity that depends on the engine rotation. However, there is a concern that a shortage of lubricating oil may occur. In addition, there is a concern that due to insufficient discharge capacity of the oil pump, the original pressure cannot be generated and the clutch pressure decreases, resulting in malfunction of the frictional engagement elements and the like, and a decrease in responsiveness to the control valve unit. As a result, there arises a problem of deterioration in response from the neutral traveling to the D range traveling. Furthermore, the vehicle speed increases on a steep downhill with a large inclination angle.

Further, in an automatic transmission control device that performs constant speed running control by shift control (shift down or up), on a gentle slope downhill with a small tilt angle, the vehicle speed increases due to an increase in engine brake accompanying the shift down. It may be extremely lowered and it may be necessary to operate the accelerator.
That is, when the total running resistance applied to the vehicle becomes larger than the downhill potential energy of the vehicle due to the operation of the engine brake, the vehicle speed decreases. I had to keep the vehicle speed by consuming gasoline.

  The present invention has been made paying attention to the above-mentioned problem, and at the time of traveling on a downhill, regardless of whether the inclination angle of the downhill is steep or not, the vehicle speed is kept constant while suppressing fuel consumption, thereby improving fuel efficiency. An object of the present invention is to provide a control device for an automatic transmission that can be used.

In order to achieve the above object, in the present invention, friction fastening means for connecting / disconnecting power transmission between a driving source having an engine and driving wheels, and downhill constant control for performing constant speed traveling control for keeping the vehicle speed constant during downhill traveling. An automatic transmission control device comprising:
Inclination angle detection means for detecting the inclination angle of the road surface on which the vehicle equipped with the automatic transmission is running is provided,
The downhill constant speed traveling control means is a semi-neutral traveling control section that executes slip engagement control of the friction engagement means while maintaining a gear ratio when traveling at a gentle inclination downhill whose inclination angle detection value is less than a set value; And a shift travel control unit that performs shift control for keeping the vehicle speed constant when traveling on a steep downhill slope whose detected tilt angle is equal to or greater than a set value.

Therefore, in the control device for an automatic transmission according to the present invention, the slip engagement control of the friction engagement means is executed while maintaining the transmission ratio in the semi-neutral traveling control unit during the gentle inclination downhill traveling, and the steep inclination downhill During travel, shift control is performed in the shift travel control unit to keep the vehicle speed constant.
That is, the vehicle speed is controlled by slip engagement control of the friction engagement means when traveling on a gentle slope downhill, and the vehicle speed is controlled by shift control when traveling on a steep downhill slope. Therefore, constant speed traveling during downhill traveling can be performed regardless of the accelerator operation or the brake operation.
As a result, when traveling downhill, the vehicle speed can be kept constant while fuel consumption is suppressed, regardless of whether the inclination angle of the downhill is gentle or not, and fuel efficiency can be improved.

  Hereinafter, the best mode for realizing a control device for an automatic transmission according to the present invention will be described based on a first embodiment shown in the drawings.

  First, the configuration will be described.

  FIG. 1 is a skeleton diagram illustrating an example of an automatic transmission to which the control device of the first embodiment is applied.

  The automatic transmission in the first embodiment is a stepped automatic transmission with 7 forward speeds and 1 reverse speed. The driving force of the engine Eg is input from the input shaft Input via the torque converter TC, and the four planetary gears and 7 The rotational speed is changed by the two frictional engagement elements, output from the output shaft Output, and transmitted to the drive wheel K.

  Further, an oil pump OP is provided coaxially with the pump impeller of the torque converter TC, and is rotated by the driving force of the engine Eg to pressurize the oil. In the figure, LUC is a lock-up clutch.

  Further, an engine controller 10 (ECU) that controls the drive state of the engine Eg, an automatic transmission controller 20 (ATCU) that controls the shift state of the automatic transmission, and the like, based on output signals of the automatic transmission controller 20. And a control valve unit 30 (CVU) for controlling the hydraulic pressure of the frictional engagement element. The engine controller 10 and the automatic transmission controller 20 are connected via a CAN communication line or the like, and share sensor information and control information with each other by communication.

  Connected to the engine controller 10 are an accelerator opening sensor 1 for detecting an accelerator pedal operation amount of a driver and an engine rotation speed sensor 2 for detecting an engine rotation speed. The engine controller 10 controls the fuel injection amount and the throttle opening based on the engine rotation speed and the accelerator pedal operation amount, and controls the engine output rotation speed and the engine torque.

  The automatic transmission controller 20 includes a first turbine rotation speed sensor 3 that detects the rotation speed of the first carrier PC1, a second turbine rotation speed sensor 4 that detects the rotation speed of the first ring gear R1, and an output shaft Output. An output shaft rotation speed sensor 5 that detects a rotation speed, an inhibitor switch 6 that detects a range position selected by a driver's shift lever, and an inclination angle sensor that detects the inclination angle of the traveling road surface based on the vehicle inclination angle ( (Tilt angle detecting means) 7 is connected. Then, an optimal command shift speed or an optimal command engagement pressure based on the detected tilt angle value, the vehicle speed Vsp, and the accelerator opening APO indicating the accelerator pedal operation amount is selected, and the command shift speed or A control command for achieving the command fastening pressure is output.

Next, a transmission gear mechanism between the input shaft Input and the output shaft Output will be described.
The first planetary gear set GS1 by the first planetary gear G1 and the second planetary gear G2 and the second planetary by the third planetary gear G3 and the fourth planetary gear G4 in order on the axis from the input shaft Input side to the output shaft Output side Gear set GS2 is arranged. Further, a first clutch C1, a second clutch C2, a third clutch C3, a first brake B1, a second brake B2, a third brake B3, and a fourth brake B4 are arranged as friction engagement elements. Further, a first one-way clutch F1 and a second one-way clutch F2 are arranged.

  The first planetary gear G1 is a single pinion planetary gear having a first sun gear S1, a first ring gear R1, and a first carrier PC1 that supports a first pinion P1 that meshes with both gears S1, R1. .

  The second planetary gear G2 is a single pinion type planetary gear having a second sun gear S2, a second ring gear R2, and a second carrier PC2 that supports a second pinion P2 meshing with both gears S2 and R2. .

  The third planetary gear G3 is a single pinion planetary gear having a third sun gear S3, a third ring gear R3, and a third carrier PC3 that supports a third pinion P3 that meshes with both gears S3 and R3. .

  The fourth planetary gear G4 is a single pinion planetary gear having a fourth sun gear S4, a fourth ring gear R4, and a fourth carrier PC4 that supports a fourth pinion P4 meshing with both the gears S4 and R4. .

  The input shaft Input is connected to the second ring gear R2 and inputs the rotational driving force from the engine Eg via the torque converter TC or the like. The output shaft Output is connected to the third carrier PC3 and transmits the output rotational driving force to the driving wheel K via a final gear or the like.

  The first ring gear R1, the second carrier PC2, and the fourth ring gear R4 are integrally connected by a first connecting member M1. The third ring gear R3 and the fourth carrier PC4 are integrally connected by a second connecting member M2. The first sun gear S1 and the second sun gear S2 are integrally connected by a third connecting member M3.

  The first planetary gear set GS1 includes four rotating elements by connecting the first planetary gear G1 and the second planetary gear G2 with the first connecting member M1 and the third connecting member M3. Is done. Further, the second planetary gear set GS2 is configured to have five rotating elements by connecting the third planetary gear G3 and the fourth planetary gear G4 by the second connecting member M2.

  In the first planetary gear set GS1, torque is input to the second ring gear R2 from the input shaft Input, and the input torque is output to the second planetary gear set GS2 via the first connecting member M1. In the second planetary gear set GS2, torque is directly input to the second connection member M2 from the input shaft Input, and is input to the fourth ring gear R4 via the first connection member M1, and the input torque is Output from 3 carrier PC3 to output shaft Output.

  The first clutch C1 (input clutch I / C) is a clutch that selectively connects and disconnects the input shaft Input and the second connecting member M2. The first clutch C1 is present in a torque transmission path from the engine Eg as a drive source to the drive wheel K, and serves as a friction engagement means that is a clutch for connecting and disconnecting power transmission between the drive source and the drive wheel K. Yes. The second clutch C2 (direct clutch D / C) is a clutch that selectively connects and disconnects the fourth sun gear S4 and the fourth carrier PC4. The third clutch C3 (H & LR clutch H & LR / C) is a clutch that selectively connects and disconnects the third sun gear S3 and the fourth sun gear S4.

  The second one-way clutch F2 is disposed between the third sun gear S3 and the fourth sun gear S4. Thereby, the third clutch C3 is released, and when the rotational speed of the fourth sun gear S4 is higher than that of the third sun gear S3, the third sun gear S3 and the fourth sun gear S4 generate independent rotational speeds. Therefore, the third planetary gear G3 and the fourth planetary gear G4 are connected via the second connecting member M2, and each planetary gear achieves an independent gear ratio.

  The first brake B1 (front brake Fr / B) is a brake that selectively stops the rotation of the first carrier PC1 with respect to the transmission case Case. The first one-way clutch F1 is disposed in parallel with the first brake B1. The second brake B2 (low brake LOW / B) is a brake that selectively stops the rotation of the third sun gear S3 with respect to the transmission case Case. The third brake B3 (2346 brake 2346 / B) is a brake that selectively stops the rotation of the third connecting member M3 that connects the first sun gear S1 and the second sun gear S2 with respect to the transmission case Case. The fourth brake B4 (reverse brake R / B) is a brake that selectively stops the rotation of the fourth carrier PC4 with respect to the transmission case Case.

  FIG. 2 is an engagement operation table showing the engagement state of each friction engagement element for each shift stage in the automatic transmission to which the automatic transmission control device of the first embodiment is applied. In FIG. 2, ◯ indicates that the frictional engagement element is in an engaged state, and (◯) indicates that the frictional engagement element is in an engaged state when the engine brake is activated. No mark indicates that the frictional engagement element is in a released state.

  In the upshift and downshift between adjacent gear speeds, the engagement state of each friction engagement element provided in the transmission gear mechanism configured as described above is released, and the one friction engagement element that has been engaged is released, By performing a change gear shift in which one released frictional engagement element is engaged, it is possible to realize a first reverse speed with seven forward speeds as described below.

  That is, in the “first speed”, only the second brake B2 is engaged, and thereby the first one-way clutch F1 and the second one-way clutch F2 are engaged. In “second speed”, the second brake B2 and the third brake B3 are engaged, and the second one-way clutch F2 is engaged. In “third speed”, the second brake B2, the third brake B3, and the second clutch C2 are engaged, and the first one-way clutch F1 and the second one-way clutch F2 are not engaged. In “fourth speed”, the third brake B3, the second clutch C2, and the third clutch C3 are engaged. In "5th gear", the first clutch C1, the second clutch C2, and the third clutch C3 are engaged. In “6th speed”, the third brake B3, the first clutch C1, and the third clutch C3 are engaged. In “7th speed”, the first brake B1, the first clutch C1, and the third clutch C3 are engaged, and the first one-way clutch F1 is engaged. In “reverse speed”, the fourth brake B4, the first brake B1, and the third clutch C3 are engaged. Here, “5th gear” is a direct connection gear, “1st gear”, “2nd gear”, “3rd gear” are underdrive gears, “6th gear”, “7th gear” Becomes the overdrive (OD) gear position.

  FIG. 3 is a shift diagram showing an example of a shift map used for shift control when the D range is selected in the automatic transmission according to the first embodiment. In FIG. 3, a solid line indicates an upshift line, and a dotted line indicates a downshift line.

  When selecting the D range, a search is made for a position where an operating point determined based on the vehicle speed Vsp from the output shaft rotation speed sensor 5 (= vehicle speed sensor) and the accelerator opening APO from the accelerator opening sensor 1 exists on the shift map. To do. Then, if the operating point does not move, or if the operating point moves and remains within one shift speed region on the shift map of FIG. 3, the current shift speed is maintained as it is. On the other hand, when the driving point moves and crosses the upshift line on the shift map of FIG. 3, the shift stage indicated by the area where the driving point after crossing is shifted from the shift stage indicated by the area where the driving point before crossing exists. The upshift command is output. Further, when the operating point moves and crosses the downshift line on the shift map of FIG. 3, the shift stage indicated by the area where the operating point after crossing is shifted from the shift stage indicated by the area where the operating point before crossing exists. The downshift command is output.

  FIG. 4 is a flowchart showing the flow of the downhill constant speed travel control process (downhill constant speed travel control means) D1 executed by the automatic transmission controller 20 of the first embodiment. Each step will be described below. To do. During the downhill constant speed traveling control process D1, shift commands (each gear command, upshift command, and downshift command) are always read.

In step S1, it is determined whether or not the road surface on which the vehicle is traveling is a downhill (whether or not a downhill condition is satisfied). If YES (downhill condition is satisfied), the process proceeds to step S2. If NO (downhill condition not established), the process proceeds to step S3.
Here, whether or not the traveling road surface is a downhill is determined based on whether or not the detected inclination angle value by the inclination angle sensor 7 is equal to or greater than the threshold value A. This threshold value A is the minimum angle in the angular range where the speed is increased in the neutral traveling with the first clutch C1 that is the friction engagement means being released. In other words, when neutral traveling is performed, the speed increasing road surface is defined as a downhill.

In step S2, following the determination that the downhill condition is established in step S1, the automatic transmission is in an overdrive (OD) shift stage when the D range is selected, and the accelerator opening APO due to accelerator release is zero. Is determined (whether or not the gear ratio condition is satisfied and the power off condition is satisfied). If YES (the gear ratio condition is satisfied and the power off condition is satisfied), the process proceeds to step S4, and NO (speed ratio is satisfied). If the condition is not satisfied or the power-off condition is not satisfied, the process proceeds to step S3.
Here, whether or not the D range is selected is determined by the input of the inhibitor switch 6, and whether or not the accelerator opening APO is zero is determined by the input of the accelerator opening sensor 1. Further, whether or not it is an overdrive shift stage is determined based on a shift command.

  In step S3, following the determination that the downhill condition is not satisfied in step S1, the gear ratio condition is not satisfied, or the power-off condition is not satisfied in step S2, normal shift control (vehicle speed Vsp and accelerator opening APO and The control based on the position where the operating point determined by is present on the shift map) is executed, and the process proceeds to return.

In step S4, following the determination that the gear ratio condition and the power-off condition are satisfied in step S3, it is determined whether or not the detected inclination angle value of the inclination angle sensor 7 is less than the set value X, and YES (inclination angle If the detected value is less than the set value X, the process proceeds to step S5. If NO (inclination angle detected value = the set value X or more), the process proceeds to step S9.
Here, the “set value X” is the maximum angle in the angular range where the total running resistance applied to the vehicle exceeds the downhill potential energy possessed by the vehicle and the vehicle decelerates with the first clutch C1 being the friction engagement means engaged. is there. In other words, this set value X is set based on the inclination angle of the downhill that decelerates when descending while operating the engine brake. A downhill with an inclination angle detection value equal to or greater than the set value X is defined as a steep downhill. Here, for example, X = 4 ° is set.

In step S5, following the determination that the detected tilt angle value in step S4 is less than the set value X, that is, when the vehicle is running on a gentle slope downhill, the increasing rate of the vehicle speed Vsp from the output shaft rotational speed sensor 5 is the first. It is determined whether or not the threshold value is larger than one threshold value α. If YES (greater than the first threshold value α), the process proceeds to step S6, and if NO (first threshold value α or less), the process proceeds to step S7.
Here, the increasing rate of the vehicle speed Vsp is an absolute value of a differential value obtained by performing a differential operation on the vehicle speed Vsp detected by the output shaft rotation speed sensor 5.

  In step S6, following the determination that the vehicle speed increase rate in step S5 is larger than the first threshold value α, that is, the vehicle speed Vsp is increasing (acceleration), the shift to the first clutch C1 is maintained while maintaining the gear position. Increase slip fastening pressure and shift to return. The slip engagement pressure is increased by increasing the command oil pressure to the first clutch C1, and the first clutch C1 approaches the engagement state.

In step S7, following the determination that the vehicle speed increase rate in step S5 is less than or equal to the first threshold value α, it is determined whether or not the decrease rate of the vehicle speed Vsp from the output shaft rotational speed sensor 5 is greater than the second threshold value β. If YES (greater than the second threshold value β), the process proceeds to step S8. If NO (second threshold value α or less), the process proceeds to return.
Here, the decreasing rate of the vehicle speed Vsp is an absolute value of a differential value obtained by performing a differential operation on the vehicle speed Vsp detected by the output shaft rotation speed sensor 5.

  In step S8, following the determination that the vehicle speed reduction rate in step S7 is larger than the second threshold value β, that is, the vehicle speed Vsp is decreasing (decelerating), the slip to the first clutch C1 while maintaining the gear position. Lower the fastening pressure and shift to return. The slip engagement pressure is lowered by lowering the command hydraulic pressure to the first clutch C1, thereby bringing the first clutch C1 closer to the released state.

  If it is determined in step S5 that the vehicle speed increase rate is equal to or less than the first threshold value α and the vehicle speed decrease rate is equal to or less than the second threshold value β in step S7, the vehicle speed change is within the set range. And the sliding engagement pressure to the first clutch C1 is maintained.

  In step S9, following the determination that the detected tilt angle value is greater than or equal to the set value X in step S4, that is, when the vehicle is running steeply, the increase rate of the vehicle speed Vsp from the output shaft rotation speed sensor 5 is the third threshold value. It is determined whether or not it is greater than γ. If YES (greater than the third threshold γ), the process proceeds to step S10, and if NO (third threshold γ or less), the process proceeds to step S11.

  In step S10, following the determination that the vehicle speed increase rate in step S9 is larger than the third threshold value γ, that is, the vehicle speed Vsp is increasing (acceleration), a downshift command is output to lower the gear position by one step. Shifts and returns to return.

  In step S11, following the determination that the vehicle speed increase rate in step S9 is less than or equal to the third threshold value γ, it is determined whether or not the vehicle speed Vsp decrease rate from the output shaft rotation speed sensor 5 is greater than the fourth threshold value δ. If YES (greater than the fourth threshold δ), the process proceeds to step S12, and if NO (fourth threshold δ or less), the process proceeds to return.

  In step S12, following the determination that the vehicle speed reduction rate in step S11 is greater than the fourth threshold value δ, that is, the vehicle speed Vsp is decreasing (decelerating), an upshift command is output to increase the shift stage by one step. And move to return.

  When it is determined in step S9 that the vehicle speed increase rate is equal to or less than the third threshold value γ, and in step S11, the vehicle speed decrease rate is equal to or less than the fourth threshold value δ, the vehicle speed change is within the set range. And fix the gear position.

  Step S4 corresponds to the inclination angle determination unit D2, steps S5 to S8 correspond to the semi-neutral travel control unit D3, and steps S9 to S12 correspond to the shift travel control unit D4.

Next, the operation will be described.
First, the “technical problem of downhill constant speed traveling control” according to the present invention will be described, and then the operation of the control device for the automatic transmission according to the first embodiment will be described as “constant speed control operation during gentle slope downhill traveling”. ”And“ constant speed control action during steep downhill driving ”will be described separately.

[Technical problem of downhill constant speed traveling control]
5A and 5B are explanatory diagrams showing the breakdown of the total running resistance applied to the vehicle traveling on the downhill. FIG. 5A shows the case where the vehicle travels at a speed of 40 km, and FIG. (C) indicates when neutral control is performed at high speed, (D) indicates when semi-neutral travel control is performed at high speed, and (E) is when shift travel control is performed at high speed Is shown.

  In the figure, “Air” indicates air resistance, “Roll” indicates rolling resistance, “AT” indicates automatic friction, “ENG” indicates engine brake, and “F1” indicates a gentle slope descent of the vehicle. The magnitude of the hill potential energy is shown, and “F2” shows the magnitude of the steep downhill hill potential energy of the vehicle. Note that the total running resistance applied to the vehicle running on the downhill at 40 km / h is 100.

  Here, when the accelerator pedal position is released when the accelerator is released on the downhill at a high speed, the engine brake is activated as shown in FIG. 5B, and the total running resistance applied to the vehicle is reduced by the vehicle. It exceeds the potential energy F1 of the inclined downhill. As a result, the vehicle speed Vsp gradually decreases on a gentle slope downhill, and it is necessary to step on the accelerator in order to keep the vehicle speed Vsp constant. Further, at this time, since the accelerator opening APO is zero and the engine speed decreases, it is necessary to further increase the accelerator pedal. Therefore, it is difficult to continuously perform the fail cut with the engine Eg.

  On the other hand, when neutral traveling control is performed when traveling downhill at high speed, as shown in FIG. 5C, the engine brake does not operate, and the total traveling resistance applied to the vehicle is the potential energy of the gently inclined downhill that the vehicle has. Below F1. As a result, the vehicle speed Vsp gradually increases even on a gentle slope downhill. Furthermore, since the engine Eg is idling controlled, there is a concern that the discharge capacity of the oil pump OP will be insufficient and the lubricating oil in the automatic transmission will be insufficient. In addition, due to insufficient discharge capacity of the oil pump, the original pressure cannot be generated and the clutch pressure is lowered, so that the operation control of each frictional engagement element and the like cannot be performed sufficiently. And it becomes difficult to predict the behavior of each part, and there is a possibility that the engine speed may be higher than allowable. Further, the control valve unit 30 does not operate, and there is a possibility that the response to the transition to the D range is lowered.

  Therefore, in the present invention, when traveling downhill, regardless of whether the inclination angle of the downhill is steep or not, downhill constant speed traveling control that can maintain a constant vehicle speed and improve fuel efficiency while suppressing fuel consumption. Do.

[Constant speed control action when running on gentle slope downhill]
FIG. 6A is a schematic diagram showing the vehicle S traveling on a gentle slope downhill DH1. Here, the inclination angle of this gentle downhill DH1 is greater than the total running resistance applied to the vehicle S than the downhill potential energy of the vehicle S, and the vehicle is decelerated with the first clutch C1 being the friction engagement means engaged. It is less than 4 ° which is the maximum angle of the angle range.

  The inclination angle sensor 7 detects the inclination angle θ1a of the vehicle, and this vehicle inclination angle θ1 is the same size as the inclination angle θ1b of the traveling road surface. Therefore, the inclination angle sensor 7 detects the inclination angle θ1b of the traveling road surface based on the vehicle inclination angle θ1a.

In such a gentle slope DH1, in a driving scene in which the driver intends to carry out inertial driving while driving at the 7th speed with the driving point P1 in FIG. 3, the accelerator speed is maintained with almost no change in the vehicle speed Vsp. There is a case where the opening APO becomes zero, the operating point moves from the P1 point to the P2 point, the gear position is the highest speed stage, and the accelerator opening APO is powered off.
At this time, in the flowchart shown in FIG. 4, the process proceeds from step S 1 → step S 2 → step S 4 → step S 5, and semi-neutral travel control is executed.

  When the increase rate of the vehicle speed Vsp becomes larger than the first threshold value α, the process proceeds from step S5 to step S6, and the slip engagement pressure of the first clutch C1 is increased while maintaining the gear position. Accordingly, the degree of slip engagement of the first clutch C1 is brought close to the engaged state, and the engine brake is applied, that is, the engine brake that is operated is increased. Therefore, the total running resistance applied to the vehicle S increases, the vehicle speed Vsp can be reduced without using a foot brake, and the vehicle speed Vsp can be kept constant.

  Further, when the increasing rate of the vehicle speed Vsp is less than or equal to the first threshold value α, the process proceeds from step S5 to step S7. When the decreasing rate of the vehicle speed Vsp is greater than the second threshold value β, the process proceeds to step S7 → step S8, and While maintaining the above, the slip engagement pressure of the first clutch C1 is lowered. As a result, the degree of slip engagement of the first clutch C1 is brought close to the released state, and the engine brake is not applied, that is, the engine brake to be operated is reduced. Therefore, the total running resistance applied to the vehicle S is reduced, the vehicle speed Vsp is increased without increasing the accelerator pedal, and the vehicle speed Vsp can be kept constant.

That is, when the accelerator opening APO is set to zero during high-speed traveling on the gentle slope downhill DH1, the semi-neutral control unit D3 executes slip engagement control of the first clutch C1 while maintaining the gear position according to the vehicle speed Vsp. . Therefore, the magnitude of the engine brake to be operated increases or decreases depending on the increase or decrease of the slip engagement pressure of the first clutch C1, that is, the degree of slip engagement of the first clutch C1, and the total running resistance increases or decreases accordingly (FIG. 5 (D) reference). In other words, the slip engagement control of the first clutch C1 is performed by adjusting the balance between the gentle slope downhill position energy F1 of the vehicle S and the total running resistance applied to the vehicle S without performing the accelerator operation or the brake operation. It can travel at high speed.
Further, since the vehicle can travel at a constant speed without performing the accelerator operation, the engine Eg can continuously perform the fail cut, and the fuel efficiency can be improved.
Further, by increasing the sliding engagement pressure of the first clutch C1, the engine Eg can be rotated at a higher speed, and the discharge capacity of the oil pump OP can be secured to the extent that lubricating oil can be secured. Therefore, it is possible to solve the problem caused by performing the neutral traveling control during traveling on the gentle slope downhill DH1.

[Constant speed control action when driving down steep slopes]
FIG. 6B is a schematic diagram showing the vehicle S traveling on the steep downhill DH2. Here, the inclination angle of the steep downhill DH2 is greater than the total running resistance applied to the vehicle S than the downhill potential energy of the vehicle S, and the vehicle is decelerated with the first clutch C1 being the friction engagement means engaged. It is 4 ° or more which is the maximum angle of the angle range.

  The inclination angle sensor 7 detects the inclination angle θ2b of the vehicle, and this vehicle inclination angle θ2b is the same size as the inclination angle θ2b of the traveling road surface. Therefore, the inclination angle sensor 7 detects the inclination angle θ2b of the traveling road surface based on the vehicle inclination angle θ2a.

  In such a steep downhill DH2, when the operating point in FIG. 3 moves from the P1 point to the P2 point, the shift speed is the highest speed, and the accelerator opening APO is turned off, it is shown in FIG. In the flowchart, the process proceeds from step S1 to step S2 to step S4 to step S9, and shift travel control is executed.

  When the increasing rate of the vehicle speed Vsp becomes larger than the third threshold γ, the process proceeds from step S9 to step S10, and a shift is performed by downshifting. As a result, the total running resistance applied to the vehicle S is greatly increased, the vehicle speed Vsp is reduced without using the foot brake, and the vehicle speed Vsp is kept constant.

  When the increase rate of the vehicle speed Vsp is equal to or less than the third threshold value γ, the process proceeds from step S9 to step S11. When the decrease rate of the vehicle speed Vsp is greater than the fourth threshold value δ, the process proceeds from step S11 to step S14. Shifting with. As a result, the total running resistance applied to the vehicle S is greatly reduced, and the vehicle speed Vsp is increased without increasing the accelerator pedal, thereby keeping the vehicle speed Vsp constant.

  That is, when the accelerator opening APO is set to zero during high-speed traveling on a steep downhill DH2, the shift travel control unit D4 executes shift control that keeps the vehicle speed Vsp constant, so the engine that operates by performing shift travel control The magnitude of the brake increases and decreases, and the total running resistance increases and decreases accordingly (see FIG. 5E). That is, at the steep downhill DH2, by performing shift control, the vehicle S can travel at a constant speed by adjusting the balance between the steep downhill position energy F2 of the vehicle S and the total running resistance applied to the vehicle S.

Next, the effect will be described.
In the automatic transmission control apparatus according to the first embodiment, the following effects can be obtained.

  (1) Friction engagement means (first clutch C1) for connecting / disconnecting power transmission between the drive source having the engine Eg and the drive wheel K, and downhill constant for performing constant speed running control for keeping the vehicle speed constant during downhill running. In a control device for an automatic transmission comprising a high-speed traveling control means (downhill constant-speed traveling control processing D1), an inclination angle detection for detecting an inclination angle of a road surface on which a vehicle equipped with the automatic transmission is traveling Means (inclination angle sensor 7), and the downhill constant speed traveling control means D1 is configured to maintain the gear ratio while maintaining the gear ratio during the gentle inclination downhill DH1 traveling where the detected inclination angle is less than the set value X. Shift running that performs shift control to keep the vehicle speed constant during semi-neutral running control unit D3 that executes slip engagement control of the first clutch C1) and steep downhill slope DH2 that has an inclination angle detection value equal to or greater than a set value X And a control unit D4. For this reason, when traveling downhill, the vehicle speed can be kept constant while suppressing fuel consumption, regardless of whether the inclination angle of the downhill is gentle or not, and fuel efficiency can be improved.

  (2) The downhill constant speed travel control means D1 is an angle at which the total traveling resistance applied to the vehicle exceeds the downhill potential energy of the vehicle and decelerates while the friction engagement means (first clutch C1) is engaged. An inclination angle determination unit D2 that compares the magnitude of the detected inclination angle value with the set value X has a maximum angle of the region as a set value X. For this reason, it is possible to appropriately distinguish between the case where the semi-neutral travel control unit D3 executes the slip engagement control of the friction engagement means and the case where the shift travel control D4 executes the shift control for keeping the vehicle speed constant. it can.

  (3) The downhill constant speed traveling control means D1 determines that the downhill condition for increasing the speed in neutral traveling with the friction engagement means (first clutch C1) released is satisfied (YES in step S1), and the accelerator. The establishment of the power-off condition by releasing the foot is defined as the execution condition of the downhill constant speed traveling control. For this reason, it is possible to reliably control engine friction that occurs during downhill travel.

  (4) The downhill constant speed traveling control means D1 determines whether the automatic transmission is capable of satisfying the downhill condition (YES in step S1) and the power off condition as conditions for executing the downhill constant speed traveling control. The establishment of the gear ratio condition that the gear ratio is an overdrive gear ratio (YES in step S2) was added. Thereby, the fuel-saving effect at the time of drive | working the long gentle downhill in a highway etc. can be improved.

  (5) When the control is executed based on the inclination angle determination, the semi-neutral travel control unit D3 increases the slip engagement pressure to the friction engagement means when determining the increase in vehicle speed (YES in step S5) (step S5). S6) When determining that the vehicle speed is decreasing (YES in step S7), the slip engagement pressure to the friction engagement means is lowered (step S8), and when it is determined that the change in vehicle speed is within the set range (step S5). (NO in step S7 and NO in step S7) is executed to maintain the slip engagement pressure to the friction engagement means. As a result, it is possible to perform control according to the increase / decrease rate of the vehicle speed Vsp, and it is possible to hold the vehicle speed more accurately.

  (6) When the control is started based on the determination of the inclination angle, the shift travel control unit D4 shifts by downshifting (YES in step S9) when determining the increase in vehicle speed (step S10), and decreases the vehicle speed. When making a determination (YES in step S11), a shift is performed by upshifting (step S12), and when determining that the vehicle speed change is within the set range (NO in step S9 and NO in step S11) Control to fix the ratio is executed. For this reason, it becomes possible to perform control according to the increase / decrease rate of the vehicle speed Vsp, and the vehicle speed can be kept constant more accurately.

  As mentioned above, although the control apparatus of the automatic transmission of this invention has been demonstrated based on Example 1, it is not restricted to this Example 1 about a concrete structure, It concerns on each claim of a claim Design changes and additions are allowed without departing from the scope of the invention.

  In the first embodiment, the first clutch C1 that is a clutch that exists in the torque transmission path and connects and disconnects the power transmission from the drive source to the drive wheel K is shown as the friction engagement means. However, the present invention is not limited to this. For example, the engagement pressure of the lockup clutch LUC may be controlled.

  In the first embodiment, the set value X is set to 4 °. However, the set value X is set to 2 °, 3 °, or 4.5 ° according to the weight of the vehicle, the friction coefficient between the tire and the road surface, or the like. It is also good. In short, the set value X may be set based on the maximum angle of the angular range in which the total running resistance applied to the vehicle exceeds the downhill potential energy of the vehicle and the vehicle is decelerated while the friction engagement means is engaged.

  In the first embodiment, an example of application to a control device for a 7-speed forward reverse 1-speed automatic transmission is shown, but other automatic transmissions having a plurality of forward shift stages and continuously variable automatic transmissions The present invention can also be applied to a control device (in this case, a forward clutch is used as a friction engagement means). Further, the present invention can be applied not only to engine vehicles but also to hybrid vehicles using an engine and a drive motor as drive sources.

1 is a skeleton diagram showing an example of an automatic transmission to which a control device of Embodiment 1 is applied. FIG. It is a fastening operation | movement table | surface which shows the fastening state of each friction fastening element for every gear stage in the automatic transmission with which the control apparatus of Example 1 was applied. FIG. 6 is a shift diagram illustrating an example of a shift map used for shift control when the D range is selected in the automatic transmission according to the first embodiment. 4 is a flowchart illustrating a flow of a downhill constant speed traveling control process executed by the automatic transmission controller 20 according to the first embodiment. It is explanatory drawing which shows the breakdown of the total running resistance applied to the vehicle which is going downhill, (A) shows the time of driving | running | working at 40 km / h, (B) was turned off by accelerator foot separation at the time of high-speed driving | running | working (C) shows when neutral control is performed at high speed, (D) shows when semi-neutral travel control is performed at high speed, and (E) shows when shift travel control is performed at high speed . (A) is a schematic diagram which shows the motor vehicle which drives a gentle slope downhill, (b) is a schematic diagram which shows the motor vehicle which drives a steep slope downhill.

Explanation of symbols

Eg engine
TC torque converter
Input Input axis
Output Output axis
OP Oil pump K Drive wheel 10 Engine controller (ECU)
20 Automatic transmission controller (ATCU)
30 Control valve unit (CVU)
DESCRIPTION OF SYMBOLS 1 Accelerator opening degree sensor 2 Engine rotational speed sensor 3 1st turbine rotational speed sensor 4 2nd turbine rotational speed sensor 5 Output shaft rotational speed sensor 6 Inhibitor switch 7 Inclination angle sensor (inclination angle detection means)
GS1 1st planetary gear set
G1 1st planetary gear
G2 2nd planetary gear
GS2 2nd planetary gear set
G3 3rd planetary gear
G4 4th planetary gear
C1 1st clutch (friction engagement means)
C2 2nd clutch
C3 3rd clutch
B1 First brake
B2 Second brake
B3 3rd brake
B4 4th brake
D1 Downhill constant speed travel control means
D2 Inclination angle judgment part
D3 Semi-neutral cruise control unit
D4 shift control unit

Claims (6)

Automatic transmission comprising friction engagement means for connecting / disconnecting power transmission between a drive source having an engine and drive wheels, and downhill constant speed traveling control means for performing constant speed traveling control for keeping the vehicle speed constant during downhill traveling In the control device of the machine,
Inclination angle detection means for detecting the inclination angle of the road surface on which the vehicle equipped with the automatic transmission is running is provided,
The downhill constant speed traveling control means is a semi-neutral traveling control section that executes slip engagement control of the friction engagement means while maintaining a gear ratio when traveling at a gentle inclination downhill whose inclination angle detection value is less than a set value; A control device for an automatic transmission, comprising: a shift travel control unit that performs shift control for maintaining a constant vehicle speed when traveling on a steep downhill slope whose detected tilt angle is equal to or greater than a set value. The control device for an automatic transmission according to claim 1,
The downhill constant speed running control means has a total running resistance applied to the vehicle higher than the downhill potential energy of the vehicle, and sets the maximum angle in the angular range where the vehicle is decelerated while the friction fastening means is engaged as a set value. A control apparatus for an automatic transmission, comprising an inclination angle determination unit that compares the detected angle value with the set value. In the control device for an automatic transmission according to claim 1 or 2,
The downhill constant speed running control means controls the downhill constant speed running control between the establishment of the downhill condition for increasing the speed in the neutral running with the friction engagement means released and the establishment of the power-off condition by releasing the accelerator pedal. A control device for an automatic transmission, characterized in that the execution condition is satisfied. In the control device for an automatic transmission according to claim 3,
The downhill constant speed traveling control means has a gear ratio condition that the automatic transmission has an overdrive gear ratio when the downhill condition is satisfied and the power-off condition is satisfied as an execution condition of the downhill constant speed traveling control. A control device for an automatic transmission, characterized in that the establishment is added. The control apparatus for an automatic transmission according to any one of claims 1 to 4,
When the control is executed based on the determination of the inclination angle, the semi-neutral traveling control unit increases the slip engagement pressure to the friction engagement means when determining the increase in the vehicle speed, and the slip engagement to the friction engagement means when determining the decrease in the vehicle speed. A control device for an automatic transmission, wherein a control for reducing a pressure and maintaining a slip engagement pressure to the friction engagement means is executed when it is determined that a change in vehicle speed is within a set range. The control apparatus for an automatic transmission according to any one of claims 1 to 5,
When the control is started based on the determination of the inclination angle, the shift travel control unit performs a shift by downshifting when determining an increase in vehicle speed, and performs a shift by upshifting when determining a decrease in vehicle speed. A control device for an automatic transmission, wherein control for fixing a gear ratio is executed when it is determined that the speed ratio is within.

Images