JP2017110701A - Control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an automatic transmission which can improve fuel economy under advantageous conditions.SOLUTION: A control device for an automatic transmission comprises a control unit 6 which decides whether or not to perform slip control on the basis of a gradient of a road surface on which a host vehicle travels, and a temperature of a clutch. When the road surface is a downhill road or a flat road and an inclination angle of the road surface is equal to a prescribed inclination angle or larger, the control unit 6 performs slip control. When the road surface is a downhill road and the inclination angle of the road surface is equal to the prescribed inclination angle or larger, the control unit 6 performs slip control with a reduced amount of slip of the clutch compared with a case where the road surface is a flat road. When the temperature of the clutch is lower than a prescribed temperature, the control unit 6 performs slip control. The slip control alternately performs an operation for bringing the clutch into a semi-fastened state for a first prescribed time, and an operation for bringing the clutch into a completely-fastened state for a second prescribed time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for an automatic transmission.

  Conventionally, a method described in Patent Document 1 is known as a method for controlling a clutch of an automatic transmission. Patent Document 1 includes a wet multi-plate clutch for shifting gears in an automatic transmission, and executes slip control on the wet multi-plate clutch when the inertial running condition is satisfied. ing.

  The thing described in Patent Document 1 is that the accelerator pedal and the brake pedal are off, and when the road surface is a flat road or a downhill road, it is determined that the coasting condition is satisfied, and slip control is performed. The fuel consumption can be improved by reducing the engine brake acting on the vehicle.

JP2013-104555A

  However, the one described in Patent Document 1 executes slip control by determining that the inertial driving condition is satisfied when the accelerator pedal and the brake pedal are off and the road surface is a flat road or a downhill road. Yes. For this reason, the temperature of the clutch becomes excessively high due to the execution of slip control, which may cause inconvenience in the vehicle. Therefore, it has been desired to achieve fuel efficiency improvement by performing slip control under suitable conditions so as not to cause inconvenience to the vehicle.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a control device for an automatic transmission that can achieve improvement in fuel consumption under suitable conditions.

  In order to achieve the above object, the present invention provides a control device for an automatic transmission that executes slip control for setting a clutch of an automatic transmission in a semi-engaged state when the vehicle is coasting. And a controller that determines whether or not to execute the slip control based on a gradient of a road surface to be performed and a temperature of the clutch.

  According to the present invention, fuel consumption can be improved under suitable conditions.

FIG. 1 is a configuration diagram showing a main part of a vehicle equipped with a control device for an automatic transmission according to an embodiment of the present invention. FIG. 2 is a flowchart showing the flow of the slip control determination operation executed by the automatic transmission control device according to the embodiment of the present invention. FIG. 3 is a timing chart showing a clutch engagement state when slip control is executed by the automatic transmission control apparatus according to the embodiment of the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3. As shown in FIG. 1, a vehicle 10 equipped with an automatic transmission control device according to an embodiment of the present invention includes an engine 1, an automatic transmission 4, a G sensor 5, an accelerator pedal sensor 7, a brake pedal sensor 8, The vehicle speed sensor 9, the drive wheel 11, and the control unit 6 are included.

  The engine 1 is a four-cycle gasoline engine that performs a series of four strokes consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, and generates a driving force of the vehicle 10 by igniting during the compression stroke and the expansion stroke. It is configured. The engine 1 may be a diesel engine.

  The automatic transmission 4 includes a transmission mechanism 2, a clutch 3, and an actuator 12. The transmission mechanism 2 is configured as a parallel shaft gear type transmission mechanism that is generally used in a manual transmission, and has a plurality of constantly meshing transmission gears.

  The clutch 3 is configured as a dry single-plate clutch, and includes a flyhole 3A connected to the crankshaft 1A of the engine 1 and a clutch disk 3B connected to the input shaft 2A of the transmission mechanism 2.

  The clutch 3 transmits the power of the engine 1 to the transmission mechanism 2 when the clutch disk 3B and the flyhole 3A are switched to the engaged (connected) state, and from the engine 1 to the transmission mechanism 2 when the clutch disk 3B is switched to the opened state. The transmission of power to is cut off.

  The actuator 12 is configured as an electric actuator or an electrohydraulic actuator, and is driven to perform a speed change operation of the automatic transmission 4. The speed change operation performed by the actuator 12 includes a clutch on / off operation for fastening or releasing the clutch 3 and a gear stage switching operation for switching the gear stage of the transmission mechanism 2. The actuator 12 is electrically connected to the control unit 6 and is controlled by a control signal from the control unit 6. Thus, the automatic transmission 4 is configured by an AMT (Automated Manual Transmission) that automates the shifting operation of the manual transmission.

  The actuator 12 includes a speed change actuator (not shown), and a gear position switching operation is performed by the speed change actuator. The actuator 12 includes a clutch actuator (not shown), and the clutch 3 is fastened or released by the clutch actuator. Specifically, the clutch actuator operates a release rod (not shown) of the automatic transmission 4 to release the clutch 3 before the gear stage switching operation and to engage the clutch 3 after the gear stage switching operation.

  In the vehicle 10 configured as described above, the rotation output from the engine 1 is shifted at a gear ratio according to the gear stage established by the automatic transmission 4, and a differential device (not shown) and the left and right drive shafts 11A are shifted. To the left and right drive wheels 11.

  Further, the automatic transmission 4 is provided with a clutch stroke sensor 17 and a clutch temperature sensor 18. The clutch stroke sensor 17 detects the degree of engagement of the clutch 3. The clutch stroke sensor 17 is electrically connected to the control unit 6 and outputs a detection signal to the control unit 6. The clutch stroke sensor 17 indirectly detects the degree of engagement of the clutch 3 by detecting the stroke amount of the release rod, for example.

  The clutch temperature sensor 18 detects the temperature of the clutch 3 (hereinafter also referred to as clutch temperature), and outputs the detected clutch temperature to the control unit 6. The clutch temperature is not limited to that actually measured by the clutch temperature sensor 18. The clutch temperature is determined from, for example, the rotational speed or engine torque of the crankshaft of the engine 1, the rotational speed or oil temperature of the input shaft 2A of the automatic transmission 4, the slip amount, the heat capacity, or the absorbed energy of the clutch 3. You may calculate.

  The G sensor 5 detects acceleration (dynamic acceleration and static acceleration), and outputs the detected acceleration to the control unit 6. Based on the acceleration transmitted from the G sensor 5, the control unit 6 calculates the inclination angle of the road surface during traveling.

  The accelerator pedal sensor 7 is provided in the accelerator pedal 7A and detects the amount of depression of the accelerator pedal 7A. The brake pedal sensor 8 is provided in the brake pedal 8A and detects the amount of depression of the brake pedal 8A.

  The vehicle speed sensor 9 is provided on the drive shaft 11A and detects the vehicle speed based on the rotational speed of the drive shaft 11A.

  The accelerator pedal sensor 7, the brake pedal sensor 8 and the vehicle speed sensor 9 are electrically connected to the control unit 6 and output detection signals to the control unit 6.

  The control unit 6 is composed of a computer unit having a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, and an output port. The control object is electrically controlled. That is, the control part 6 is comprised from ECU (Electronic Control Unit).

  The ROM of the control unit 6 stores a program for causing the computer unit to function as the control unit 6 along with various control constants and various maps. That is, in the control unit 6, the computer unit functions as the control unit 6 when the CPU executes a program stored in the ROM.

  Various sensors such as the clutch stroke sensor 17, the accelerator pedal sensor 7, the brake pedal sensor 8, and the vehicle speed sensor 9 described above are connected to the input port of the control unit 6.

  The engine 1 and the actuator 12 of the automatic transmission 4 are connected to the output port of the control unit 6. Based on the driving state of the vehicle 10, such as the accelerator pedal depression amount detected by the accelerator pedal sensor 7, the brake pedal depression amount detected by the brake pedal sensor 8, the vehicle speed detected by the vehicle speed sensor 9, the control unit 6. And the automatic transmission 4 is controlled.

  Whether the control unit 6 performs the slip control based on the road surface inclination angle calculated from the G sensor 5, the clutch temperature, the depression amount of the accelerator pedal 7A, and the depression amount of the brake pedal 8A. To decide.

  The slip control is control for bringing the clutch 3 into a semi-engaged state. As shown in FIG. 3, in the slip control, the first predetermined time T1, the operation of setting the clutch 3 in a semi-engaged state, and the second predetermined time T2 of the clutch 3 in the fully engaged state (the clutch engagement degree is 100%). ) Are performed alternately.

  Further, the control unit 6 performs the slip control based on the road surface inclination angle calculated from the G sensor 5, the clutch temperature, the depression amount of the accelerator pedal 7A, and the depression amount of the brake pedal 8A. The target slip amount (also called the target slip amount) is set.

  The control unit 6 performs feedback control so that the actual slip amount of the clutch 3 follows the target slip amount. Here, as an actual slip amount at the time of performing feedback control, a slip amount as an actual measurement value based on a detection signal of the clutch stroke sensor 17 or a slip amount as an estimated value based on the hydraulic pressure of the actuator 12 or the like is used. it can.

  In the present embodiment, the control unit 6 executes the slip control of the clutch 3 on the condition that the vehicle 10 is traveling inertially. Inertia travel means that the vehicle 10 travels by inertia without any depression of the accelerator pedal 7A and the brake pedal 8A. Moreover, the control part 6 improves a fuel consumption by implementing a fuel cut while the vehicle 10 is coasting.

  Further, the control unit 6 determines whether or not to execute the slip control based on the road surface gradient on which the host vehicle travels and the clutch temperature. Regarding the road surface gradient, the control unit 6 executes slip control when the road surface is a downhill road or a flat road and the road surface has an inclination angle equal to or greater than a predetermined inclination angle.

  In other words, the control unit 6 executes slip control when the road surface is a flat road or a gentle downhill road, and does not execute the slip control when the road surface is an uphill road or a steep downhill road. This is because coasting is rarely continued for a long period of time above a certain level on an uphill road. Further, if slip control is executed on a steep downhill road, the engine brake is not effective and the vehicle 10 is accelerated, and a load is applied to the braking device.

  Further, the control unit 6 compares the road surface with a flat road when the road surface is a downhill road and the road surface has an inclination angle equal to or greater than a predetermined inclination angle, that is, when the road surface is a gentle downhill road. Slip control is executed by decreasing the slip amount of the clutch 3. Further, the control unit 6 performs slip control when the clutch temperature is lower than a predetermined temperature in order to protect the clutch 3.

  When slip control is performed when the road surface is a gentle downhill road, the automatic transmission 4 is not shifted down and the gear position is maintained so that a large engine brake does not act on the drive wheels 11. Yes.

  Next, the flow of the slip control determination operation executed by the control unit 6 according to the present embodiment will be described with reference to FIG. This slip control determination operation is repeatedly executed at a predetermined short cycle. Further, the slip control determination operation may be performed all the time when the vehicle is traveling, or may be performed on condition that the vehicle is traveling at a predetermined speed or more.

  As shown in FIG. 2, the control unit 6 determines whether or not the accelerator is off and the brake is off (step S1). Here, the control unit 6 refers to the detection signals of the accelerator pedal sensor 7 and the brake pedal sensor 8 and detects that the accelerator pedal 7A is not depressed and the brake pedal 8A is not depressed. Then, it is determined that the accelerator is off and the brake is off.

  If it is determined that the accelerator is off and the brake is off, the control unit 6 determines that the vehicle is coasting and proceeds to step S2, and if it is determined that the accelerator is not off and the brake is off, this step control determination operation This one routine is terminated.

  In step S2, the control unit 6 determines whether or not the road surface on which the host vehicle travels is a flat road or a downhill road. Here, the control unit 6 calculates the tilt angle of the vehicle based on the information transmitted from the G sensor 5. In the present embodiment, a positive inclination angle is defined as an uphill road, a flat road is defined when the inclination angle is 0, and a negative inclination angle is defined as a downhill road. In step S2, when the inclination angle is 0 or a negative value, it is determined that the road surface is a flat road or a downhill road.

  Note that the control unit 6 is not limited to the detection signal from the G sensor 5, and may calculate the tilt angle from the altitude information included in the map information, or may acquire the tilt angle by communication from the outside of the vehicle. Good. That is, the inclination angle may be either acquired from the sensor of the host vehicle or acquired from the outside of the vehicle.

  If the controller 6 determines in step S2 that the road surface is a flat road or a downhill road, since it is not an uphill road, it is unlikely that the accelerator pedal 7A will be depressed, so one of the slip control execution conditions is satisfied. Then, the process proceeds to step S3.

  On the other hand, when it is determined in step S2 that the road surface is neither a flat road nor a downhill road, that is, when the road surface is an uphill road (inclination angle is a positive value), the slip control execution condition is set. If not satisfied, one routine of this step control determination operation is terminated.

  In step S3, the control unit 6 determines whether or not the road surface inclination angle is equal to or greater than a predetermined inclination angle α. In the present embodiment, the predetermined inclination angle α is set to a negative value.

  If it is determined in step S3 that the slope of the road surface is equal to or greater than the predetermined slope angle α, the controller 6 is a flat road (the slope angle is 0) or a gentle downhill road and does not require a large engine brake. Then, assuming that one of the slip control execution conditions is satisfied, the process proceeds to step S4.

  On the other hand, if the control unit 6 determines that the road surface inclination angle is less than the predetermined inclination angle α in step S3, the control unit 6 is a steep downhill road and requires a large engine brake. If not, the routine for this step control determination operation is terminated once.

  In step S4, the control unit 6 determines whether or not the clutch temperature is lower than a predetermined temperature T. Here, the control unit 6 compares the clutch temperature with the predetermined temperature T in order to confirm whether the clutch temperature does not become too high when the slip control is executed.

  When it is determined in step S4 that the clutch temperature is lower than the predetermined temperature T, the control unit 6 proceeds to step 5 on the assumption that one of the slip control execution conditions is satisfied without the clutch temperature being excessively high.

  On the other hand, if the control unit 6 determines that the clutch temperature is equal to or higher than the predetermined temperature T in step S4, the clutch temperature may be too high. One routine of determination operation is completed.

  In step S5, the control unit 6 determines whether or not the road surface is a flat road. When it is determined in step S5 that the road surface is a flat road, the control unit 6 proceeds to step S6 and executes slip control with the slip amount A%.

  On the other hand, when it is determined in step S5 that the road surface is not a flat road (when the road surface is a gentle downhill road), the control unit 6 proceeds to step S7 and executes slip control with the slip amount B%. After executing the slip control in step S6 or step S7, the control unit 6 ends one routine of the step control determination operation.

  Here, the slip amount represents the degree of engagement of the clutch 3 as the amount of slip of the clutch 3. For example, the slip amount is 0% when the clutch 3 is completely engaged and the engagement degree is 100%, and the slip amount is 100 when the clutch 3 is completely released (disconnected) and the engagement degree is 0%. %become. Thus, the slip amount of the clutch 3 is a value that increases or decreases in the opposite direction with respect to the degree of engagement.

  In the present embodiment, the slip amount B% is set to a value smaller than the slip amount A%. As a result, when the road surface is a gentle downhill road (NO in step S5), a larger engine brake is required than in the case where the road surface is a flat road. By executing the slip control at the above, a larger engine brake can be applied than in the case of a flat road.

  In addition, the case where the inclination angle is strictly 0 is not limited to a flat road, but the case where the inclination angle is within a predetermined range including 0 may be a flat road. When the slope is within a predetermined range and the road is a flat road, the control unit 6 determines that the slope is larger than the upper limit threshold of the predetermined range as an uphill road, and the case where the slope is smaller than the lower limit threshold of the predetermined range. Judged as a downhill road.

  Next, the operation of the control device for the automatic transmission according to the present embodiment will be described. While the slip control is being executed, the clutch 3 is in a semi-engaged state, so that the engine brake transmitted from the engine 1 to the drive wheels 11 via the clutch 3 is reduced.

  For this reason, it is possible to extend the travel distance by coasting while performing fuel cut, so that an improvement in fuel consumption can be achieved. On the other hand, if the slip control is executed when the road surface has a steep downward slope, sufficient engine brake cannot be obtained.

  During the slip control, the clutch 3 is in a semi-engaged state, so that the temperature of the clutch 3 rises due to frictional heat. For this reason, it is necessary to consider that the temperature of the clutch 3 does not become too high due to the slip control being executed.

  Therefore, in the present embodiment, the control unit 6 determines whether or not to execute the slip control based on the road surface gradient on which the host vehicle travels and the temperature of the clutch 3 in addition to whether or not the vehicle is coasting. Is determined.

  With this configuration, the engine brake is ensured and the clutch 3 is prevented from becoming high temperature, so that fuel efficiency can be improved under suitable conditions.

  In the control device for an automatic transmission according to the present embodiment, the control unit 6 performs slip control when the road surface is a downhill road or a flat road and the road surface has an inclination angle equal to or greater than a predetermined inclination angle α. Run.

  With this configuration, the slip control is executed on a flat road and a gentle downhill road where the reduction of the engine brake is allowed. For this reason, fuel consumption can be improved under suitable conditions.

  In the control device for an automatic transmission according to the present embodiment, the control unit 6 determines that the road surface is a flat road when the road surface is a downhill road and the road surface has an inclination angle equal to or greater than a predetermined inclination angle α. Compared with the case, the slip amount of the clutch 3 is decreased and the slip control is executed.

  With this configuration, the engine braking required for a gentle downhill road can be maintained by performing slip control on a gentle downhill road by reducing the slip amount compared to a flat road.

  In the control device for an automatic transmission according to the present embodiment, the control unit 6 executes slip control when the temperature of the clutch 3 is lower than a predetermined temperature T.

  With this configuration, when the temperature of the clutch 3 is lower than the predetermined temperature T, the slip control is executed, so that the clutch 3 can be prevented from becoming high temperature. For this reason, fuel consumption can be improved under suitable conditions.

  In the control device for an automatic transmission according to the present embodiment, the slip control includes an operation for setting the clutch 3 in the semi-engaged state for the first predetermined time and an operation for setting the clutch 3 in the fully engaged state for the second predetermined time. This control is performed alternately.

  Here, if the slip control is performed in a state where the clutch 3 is in an open state, although the inertial mileage can be extended, the engine rotation speed decreases rapidly, so the fuel cut execution condition is not satisfied, The fuel cut ends at an early timing.

  In contrast, in the present embodiment, the slip control is performed in such a manner that the operation of bringing the clutch 3 into the semi-engaged state and the operation of bringing the clutch 3 into the fully engaged state are alternately performed, so that the fuel cut execution condition is satisfied for a long time. Can do.

  Moreover, the temperature rise of the clutch 3 can be suppressed by performing alternately the operation | movement which makes the clutch 3 a semi-engagement state, and the operation | movement which makes a complete engagement state. As a result, fuel efficiency can be improved under suitable conditions.

  While embodiments of the present invention have been disclosed as described above, it will be apparent to those skilled in the art that changes may be made without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

  In the present embodiment, slip control is performed for the clutch 3 configured as a starting device composed of a dry single-plate clutch, but the target of slip control is not limited to such a clutch 3. .

  For example, when the vehicle 10 includes a torque converter with a lock-up clutch, the lock-up clutch can be a target for slip control.

  Further, when the automatic transmission 4 is provided with a gear for changing gears and a brake, the gear for changing gears can be set as a target for slip control. Note that the shift speed changing clutch is generally a wet multi-plate clutch.

3 Clutch 4 Automatic transmission 6 Control unit 10 Vehicle

Claims (5)

A control device for an automatic transmission that executes slip control that puts the clutch of the automatic transmission into a semi-engaged state when the vehicle is coasting,
An automatic transmission control device comprising: a control unit that determines whether or not to execute the slip control based on a gradient of a road surface on which the host vehicle travels and a temperature of the clutch.   The said control part performs the said slip control, when the said road surface is a downhill road or a flat road, and the inclination angle of the said road surface is more than predetermined inclination angle, The said control is performed. Control device for automatic transmission.   The control unit reduces the slip amount of the clutch when the road surface is a downhill road and the road surface has an inclination angle equal to or larger than a predetermined inclination angle compared to a case where the road surface is a flat road. The control apparatus for an automatic transmission according to claim 2, wherein the slip control is executed.   4. The control device for an automatic transmission according to claim 1, wherein the controller performs the slip control when a temperature of the clutch is lower than a predetermined temperature. 5. .   The slip control is a control for alternately performing an operation for bringing the clutch into a semi-engaged state for a first predetermined time and an operation for bringing the clutch into a fully engaged state for a second predetermined time. The control device for an automatic transmission according to any one of claims 1 to 4.