JP5534212B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device that improves control of a transmission mechanism when idling stop control of an internal combustion engine is executed.

  In general, an automatic transmission mounted on a vehicle is provided with a plurality of friction engagement elements such as clutches and brakes in a transmission mechanism, and by individually controlling the hydraulic pressure applied to each of these friction engagement elements, By selectively switching between engagement and disengagement of the friction engagement elements, the shift stage (speed ratio) of the transmission mechanism is switched.

  In recent years, some vehicles equipped with an internal combustion engine employ an idling stop control system for the purpose of reducing fuel consumption and exhaust emissions. In this idling stop control system, for example, when the driver stops or decelerates the vehicle during operation of the internal combustion engine and an automatic stop request is generated, the fuel injection of the internal combustion engine is stopped (fuel cut) and the internal combustion engine is automatically operated. Then, when the driver performs an operation to start or accelerate the vehicle during the automatic stop of the internal combustion engine (fuel cut), the fuel injection is resumed when a restart request is generated. The engine is automatically restarted (see Patent Documents 1 and 2).

JP-A-7-266932 JP 2009-250071 A

  By the way, when idling stop control is executed in a state in which a travel range such as the D range (drive range) is selected and the transmission mechanism of the automatic transmission is maintained in the power transmission state, The engine starting torque is transmitted to the wheel side through the speed change mechanism, which may cause an unpleasant shock.

  As a countermeasure, the applicant reduces the hydraulic pressure applied to the engagement side clutch (friction engagement element that is engaged in the travel range) of the transmission mechanism during the automatic stop of the internal combustion engine, thereby reducing the engagement side clutch. To a semi-engaged state (slip state), and then after the restart of the internal combustion engine is completed (for example, after the rotational speed of the internal combustion engine has dropped below the peak value), the hydraulic pressure applied to the engagement side clutch is increased. The system that returns the engaged clutch to the engaged state (power transmission state) has been studied.

  When the operating characteristics of the engagement-side clutch with respect to the hydraulic pressure change due to system manufacturing variations or changes over time (for example, the hydraulic pressure value at which the engagement-side clutch is half-engaged changes), the idling stop control of the internal combustion engine is performed. In addition, there is a possibility that the hydraulic pressure applied to the engagement side clutch cannot be properly controlled. For example, if the hydraulic pressure when the engagement side clutch is in the half-engaged state is too high, the engagement side clutch is sufficiently slipped. This may cause an uncomfortable shock when the internal combustion engine is restarted. In addition, if the hydraulic pressure when the engagement side clutch is brought into the semi-engagement state is too low, it takes a long time to increase the hydraulic pressure and return the engagement side clutch to the engagement state after completion of restart of the internal combustion engine. It may be difficult to quickly start or accelerate the vehicle.

  Therefore, a problem to be solved by the present invention is to provide a vehicle control device capable of appropriately controlling the hydraulic pressure applied to the frictional engagement element on the engagement side of the transmission mechanism during idling stop control of the internal combustion engine. It is to provide.

In order to solve the above-mentioned problem, the invention according to claim 1 is applied to a vehicle that transmits the power of the internal combustion engine to the wheel side via the speed change mechanism, and is applied to a friction engagement element provided in the speed change mechanism. By continuously controlling the power transmission of the transmission mechanism, the combustion of the internal combustion engine is stopped when a predetermined automatic stop condition is satisfied, and the internal combustion engine is restarted when the predetermined restart condition is satisfied. In a vehicle control device having an idling stop control means for starting, a hydraulic pressure applied to a friction engagement element on the engagement side of the transmission mechanism is reduced during combustion stop of the internal combustion engine to reduce the friction engagement element on the engagement side. The pressure reduction control means for executing the pressure reduction control to make the release state, and the hydraulic pressure applied to the friction engagement element on the engagement side when the internal combustion engine is restarted are increased to bring the friction engagement element on the engagement side into the half engagement state. Friction engagement on the engagement side after A pressure increase control means for performing pressure control increasing the element into engagement, the vehicle speed to determine whether within a predetermined range indicating that a deceleration during the combustion stop of the internal combustion engine, the oil temperature is either within a predetermined range A learning execution condition determining means for determining that the hydraulic pressure learning execution condition is satisfied when the vehicle speed is determined to be within the predetermined range and the oil temperature is determined to be within the predetermined range; Calculation of the rotational speed difference between the output side rotational speed of the speed change mechanism and the input shaft rotational speed is started when it is determined that the relationship is established, and the engagement side when the rotational speed difference is greater than or equal to the learning determination value Hydraulic pressure learning means for learning the hydraulic pressure command value of the frictional engagement element as a hydraulic pressure at which the frictional engagement element on the engagement side begins to slide (hereinafter referred to as “reference hydraulic pressure”). Based on the learning value of the reference oil pressure learned by the oil pressure learning means, It is obtained so as to control the hydraulic pressure to be applied to Kosugakarigo element.

  In this configuration, pressure reduction control is performed to reduce the hydraulic pressure applied to the engagement-side friction engagement element while the combustion of the internal combustion engine is stopped, and to release the engagement-side friction engagement element, and then the internal combustion engine. The hydraulic pressure applied to the engagement side frictional engagement element at the time of restart is increased to bring the engagement side frictional engagement element into a semi-engagement state (slip state), and then the engagement side frictional engagement element is engaged. The pressure increase control for returning to the combined state can be executed. As a result, when the internal combustion engine is restarted, the frictional engagement element on the engagement side can be brought into a semi-engaged state, and the start torque of the internal combustion engine can be prevented from being transmitted to the wheel side via the speed change mechanism. , Can prevent the occurrence of unpleasant shock.

Further, it is determined whether or not the vehicle speed is within a predetermined range indicating that the vehicle speed is decelerating while the combustion of the internal combustion engine is stopped, it is determined whether or not the oil temperature is within a predetermined range, the vehicle speed is determined to be within the predetermined range, and the oil temperature Is determined to be within the predetermined range, it is determined that the hydraulic pressure learning execution condition is satisfied, and calculation of the rotational speed difference between the output side rotational speed of the transmission mechanism and the input shaft rotational speed is started. There engagement hydraulic pressure command value of the engagement side frictional engagement element to learn the reference hydraulic pressure (oil pressure start slipping frictional engagement element on the engagement side), the pressure reduction control and the pressure increase control of when it becomes more than learning determination value At this time, it is possible to control the hydraulic pressure applied to the frictional engagement element on the engagement side with reference to the learned value of the reference hydraulic pressure. As a result, even if the operating characteristics of the frictional engagement element on the engagement side with respect to the hydraulic pressure change due to system manufacturing variations, changes over time, etc. It is possible to appropriately control the hydraulic pressure applied to the friction engagement element. As a result, the vehicle can be started or accelerated promptly after restarting while preventing an unpleasant shock from occurring when the internal combustion engine is restarted.

Further, in the pressure reduction control, as described in claim 2 , after the automatic stop condition is satisfied, the first correction value is added and corrected to the learning value of the reference hydraulic pressure when the pressure reduction control start condition is satisfied . It is preferable to set the hydraulic pressure as the initial hydraulic pressure for pressure reduction control. Thus, the initial oil pressure of the pressure reduction control, the reference hydraulic pressure of the academic習値can be set by properly corrected, the time of pressure reduction control, the hydraulic pressure to be applied to the frictional engagement element on the engagement side By reducing the initial hydraulic pressure, the reference hydraulic pressure can be learned reliably and promptly during the pressure reduction control.

Further, when the pressure reduction control, as claimed in claim 2, so that the reference hydraulic pressure to set the hydraulic pressure of the second correction value with respect to the reference hydraulic pressure of the learned value obtained by subtracting corrected after being learned as the final hydraulic pressure of the pressure reduction control It is good to make it. In this way, the final hydraulic pressure of the pressure reduction control can be set to a hydraulic pressure that makes the frictional engagement element on the engagement side to be in a released state by being appropriately lower than the reference hydraulic pressure. By controlling the hydraulic pressure applied to the frictional engagement element on the mating side to the final hydraulic pressure, the frictional engagement element on the engagement side can be surely and quickly released.

  Here, the output shaft rotational speed of the speed change mechanism changes according to the vehicle speed, and the hydraulic pressure at which the engagement-side frictional engagement element starts to slide changes, and the fluidity of the hydraulic oil changes according to the oil temperature. Since the hydraulic pressure at which the frictional engagement element on the mating side begins to slide changes, the actual reference hydraulic pressure (hydraulic pressure at which the frictional engagement element on the engagement side begins to slide) varies depending on the vehicle speed and the oil temperature at that time.

In consideration of such circumstances, as in claim 3 , the first correction value and the second correction value may be calculated based on the vehicle speed and the oil temperature. In this way, the first correction value and the second correction value are changed in response to the change of the reference hydraulic pressure (the hydraulic pressure at which the engagement-side frictional engagement element starts to slide) according to the vehicle speed and the oil temperature. Thus, the initial hydraulic pressure and final hydraulic pressure for pressure reduction control can be set to appropriate values.

In the pressure increase control, as described in claim 2 , when the restart condition is satisfied, the hydraulic pressure obtained by subtracting and correcting the third correction value from the learning value of the reference hydraulic pressure is set as the initial hydraulic pressure for the pressure increase control. It is better to set as. In this way, the initial hydraulic pressure of the pressure increase control can be set to a hydraulic pressure that makes the frictional engagement element on the engagement side a semi-engaged state (slip state) slightly lower than the reference hydraulic pressure. By controlling the hydraulic pressure applied to the frictional engagement element on the engagement side to the initial hydraulic pressure during the pressure control, the frictional engagement element on the engagement side can be surely and quickly brought into the semi-engaged state.

In this case, as in claim 3 , the third correction value may be calculated based on the vehicle speed and the oil temperature. In this way, in response to the change in the reference hydraulic pressure (the hydraulic pressure at which the engagement-side frictional engagement element starts to slide) according to the vehicle speed and the oil temperature, the third correction value is changed to perform the pressure increase control. The initial hydraulic pressure can be set to an appropriate value.

FIG. 1 is a diagram showing a schematic configuration of an entire automatic transmission according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing the mechanical configuration of the automatic transmission. FIG. 3 is a diagram showing a combination of clutch / brake engagement / release for each gear position. FIG. 4 is a time chart for explaining pressure reduction control and pressure increase control. FIG. 5 is a flowchart for explaining the flow of processing of the fuel cut control routine. FIG. 6 is a flowchart for explaining the processing flow of the engine automatic stop condition determination routine. FIG. 7 is a flowchart for explaining the flow of processing of the starter control routine. FIG. 8 is a flowchart for explaining the processing flow of the clutch hydraulic pressure control routine. FIG. 9 is a flowchart for explaining the flow of processing of the decompression control routine. FIG. 10 is a flowchart for explaining the processing flow of the hydraulic pressure learning condition determination routine. FIG. 11 is a flowchart for explaining the flow of processing of the pressure increase control routine. FIG. 12A is a diagram conceptually illustrating an example of a map of correction values A1, and FIG. 12B is a diagram conceptually illustrating an example of a map of correction values A2. FIG. 13A is a diagram conceptually illustrating an example of the map of the correction value B1, and FIG. 13B is a diagram conceptually illustrating an example of the map of the correction value B2. FIG. 14A is a diagram conceptually illustrating an example of a map of correction values C1, and FIG. 14B is a diagram conceptually illustrating an example of a map of correction values C2.

Hereinafter, an embodiment embodying a mode for carrying out the present invention will be described.
First, a schematic configuration of the automatic transmission 11 will be described with reference to FIGS. 1 and 2.
As shown in FIG. 2, an input shaft 13 of a torque converter 12 is connected to an output shaft of an engine (not shown), and a hydraulically driven transmission gear mechanism 15 (speed change) is connected to the output shaft 14 of the torque converter 12. Mechanism). Inside the torque converter 12, a pump impeller 31 and a turbine runner 32 constituting a fluid coupling are provided to face each other, and a stator 33 for rectifying the flow of oil is provided between the pump impeller 31 and the turbine runner 32. It has been. The pump impeller 31 is connected to the input shaft 13 of the torque converter 12, and the turbine runner 32 is connected to the output shaft 14 of the torque converter 12.

  The torque converter 12 is provided with a lock-up clutch 16 for engaging or disengaging between the input shaft 13 side and the output shaft 14 side. The engine output torque is transmitted to the transmission gear mechanism 15 via the torque converter 12, and is shifted by a plurality of gears (front planetary gear 23, rear planetary gear 22 and the like) of the transmission gear mechanism 15 to drive the vehicle drive wheels (front wheels or Is transmitted to the rear wheels. The transmission gear mechanism 15 is provided with a plurality of clutches RC, HC, LC and brakes B0, B1, which are a plurality of friction engagement elements for switching a plurality of shift stages, and a one-way clutch 34 (OWC). As shown in FIG. 3, the gear ratio is switched by switching the engagement / release of the clutches RC, HC, LC and the brakes B0, B1 by hydraulic pressure and switching the combination of gears for transmitting power. It is like that.

  Here, the one-way clutch 34 regulates torque transmission only in one direction (vehicle driving direction), and a brake B1 (OWC parallel clutch) is provided in parallel with the one-way clutch 34.

  FIG. 3 shows the engagement combination of the clutches RC, HC, LC and brakes B0, B1 of the four-speed automatic transmission. The circles are held in the engaged state (torque transmission state) at that gear stage. The clutch and brake are shown, and the unmarked state shows the released state.

  For example, when the accelerator is depressed in the D range (drive range), the speed is upshifted to the first speed, the second speed, the third speed, and the fourth speed as the vehicle speed increases. In the shift from the first speed to the second speed, B0 is newly engaged from the LC engagement state. In the shift from the second speed to the third speed, B0 is released from the engaged state of LC and B0, and HC is newly engaged. In the shift from the 3rd speed to the 4th speed, the LC is released from the engaged state of the HC and the LC, and B0 is newly engaged. In the L range (low range), the LC and B1 are engaged. In the R range (reverse range), the RC and B1 are engaged. In the P range (parking range) and N range (neutral range), all the friction engagement elements are released.

  As shown in FIG. 1, the transmission gear mechanism 15 is provided with a hydraulic pump 18 driven by engine power and an electric hydraulic pump 24 driven by a motor (not shown). During engine operation, hydraulic pressure is supplied by an engine-driven hydraulic pump 18, and during idling stop, which will be described later, the engine-driven hydraulic pump 18 is stopped, so that hydraulic pressure is supplied by an electric hydraulic pump 24. It has become.

  A hydraulic control circuit 17 is provided in an oil pan (not shown) that stores hydraulic oil (oil). The hydraulic control circuit 17 includes a line pressure control circuit 19, an automatic transmission control circuit 20, a lockup control circuit 21, a manual switching valve 26, and the like, and is pumped up from an oil pan by a hydraulic pump 18 (or a hydraulic pump 24). The hydraulic fluid is supplied to the automatic transmission control circuit 20 and the lockup control circuit 21 via the line pressure control circuit 19.

  The line pressure control circuit 19 is provided with a hydraulic control valve (not shown) for line pressure control that controls the hydraulic pressure from the hydraulic pump 18 (or the hydraulic pump 24) to a predetermined line pressure. Are provided with a plurality of shift hydraulic control valves (not shown) for controlling the hydraulic pressure supplied to the clutches RC, HC, LC of the transmission gear mechanism 15 and the brakes B0, B1. The lockup control circuit 21 is provided with a lockup control hydraulic control valve (not shown) for controlling the hydraulic pressure supplied to the lockup clutch 16.

  A manual switching valve 26 that is switched in conjunction with the operation of the shift lever 25 is provided between the line pressure control circuit 19 and the automatic transmission control circuit 20. When the shift lever 25 is operated to the N range (neutral range) or the P range (parking range), even if the power supply to the hydraulic control valve of the automatic transmission control circuit 20 is stopped (OFF), The hydraulic pressure supplied to the transmission gear mechanism 15 by the manual switching valve 26 is switched so that the transmission gear mechanism 15 is in a neutral state.

  On the other hand, the engine is provided with an engine rotation speed sensor 27 that detects an engine rotation speed Ne (the rotation speed of the input shaft 13 of the torque converter 12). The transmission gear mechanism 15 has an input shaft rotation speed of the transmission gear mechanism 15. An input shaft rotation speed sensor 28 that detects Nt (turbine rotation speed that is the rotation speed of the output shaft 14 of the torque converter 12) and an output shaft rotation speed sensor 29 that detects the output shaft rotation speed No of the transmission gear mechanism 15 are provided. It has been.

  Output signals of these various sensors are input to an automatic transmission electronic control circuit (hereinafter referred to as “AT-ECU”) 30. The AT-ECU 30 is mainly composed of a microcomputer, and functions as a shift control means by executing each routine stored in a built-in ROM (storage medium), and a transmission gear mechanism according to a preset shift pattern. The transmission gears are controlled by controlling the energization of each hydraulic control valve of the automatic transmission control circuit 20 in accordance with the operating position of the shift lever 25 and the operating conditions (throttle opening, vehicle speed, etc.) so that 15 shifts are executed. By controlling the hydraulic pressure applied to each clutch RC, HC, LC and each brake B0, B1 of the mechanism 15, as shown in FIG. 3, the engagement / engagement between each clutch RC, HC, LC and each brake B0, B1 is shown. The gear ratio of the transmission gear mechanism 15 is switched by switching the release and switching the combination of gears that transmit engine power.

  Furthermore, the AT-ECU 30 is connected to the engine control device 37 and transmits and receives control signals and the like between them. The engine control device 37 is configured by one or a plurality of ECUs (for example, an engine ECU and an idling stop ECU). The engine control device 37 includes various sensors (for example, an air flow meter, a throttle opening sensor, an intake pipe pressure sensor, an exhaust gas sensor, a coolant temperature sensor, a crank angle sensor, a brake switch, an accelerator sensor, a vehicle speed sensor) Etc.) is input.

  The engine control device 37 controls the fuel injection amount, the intake air amount (throttle opening), the ignition timing, and the like according to the operation state detected by the various sensors during engine operation. Furthermore, the engine control device 37 also functions as an idling stop control means in the claims, and an automatic stop request is generated (the automatic stop condition is satisfied) when the driver stops or decelerates the vehicle during engine operation. Sometimes, the engine fuel injection is stopped (fuel cut) and the engine combustion is automatically stopped, and then the driver tries to start or accelerate the vehicle during the engine automatic stop (fuel cut). Idling stop control that resumes fuel injection and automatically restarts the engine when a restart request is generated (restart condition is satisfied) by performing an operation (for example, brake depression release, accelerator depression operation, etc.) Run.

  By the way, when the idling stop control is executed in a state where the traveling range such as the D range (drive range) is selected and the transmission gear mechanism 15 of the automatic transmission 11 is maintained in the power transmission state, the engine is restarted. The engine starting torque is transmitted to the wheel side via the transmission gear mechanism 15 and uncomfortable shock may occur.

  As a countermeasure, in this embodiment, the hydraulic pressure applied to the engagement side clutch (the friction engagement element that is engaged in the travel range) of the transmission gear mechanism 15 is reduced during the fuel cut (combustion stop) of the engine. The decompression control is performed to release the engagement side clutch, and then the hydraulic pressure applied to the engagement side clutch is increased when the engine is restarted to bring the engagement side clutch into the half engagement state (slip state). After that, the pressure increasing control for returning the engagement side clutch to the engaged state is executed. As a result, when the engine is restarted, the engagement-side clutch is brought into a half-engaged state, and transmission of the engine starting torque to the wheel side via the transmission gear mechanism 15 is suppressed.

  Further, during the pressure reduction control, the reference hydraulic pressure (the hydraulic pressure at which the engagement side clutch starts to slip) is learned based on the input shaft rotation speed Nt and the output shaft rotation speed No of the transmission gear mechanism 15, and the pressure reduction control and pressure increase control are performed. Then, the hydraulic pressure applied to the engagement side clutch is controlled based on the learning value of the reference hydraulic pressure. As a result, even if the operating characteristics of the engagement side clutch with respect to the hydraulic pressure change due to system manufacturing variations, changes over time, etc., the hydraulic pressure that is applied to the engagement side clutch during pressure reduction control or pressure increase control without being affected by it. Is controlled appropriately.

Specifically, as shown in FIG. 4, first, at the time t1 when the engine automatic stop condition is satisfied, the engine fuel cut is started and the combustion of the engine is automatically stopped. Thereafter, at a time point t2 when a predetermined decompression control start condition is satisfied, the decompression control of the engagement side clutch (for example, the clutch LC) is executed. In this pressure reduction control, first, the hydraulic pressure obtained by adding and correcting the correction value A (first correction value) to the learned value of the reference hydraulic pressure (for example, the reference hydraulic pressure learned during the previous pressure reduction control ) is set as the initial hydraulic pressure of the pressure reduction control. Then, the hydraulic pressure command value of the engagement side clutch is set to the initial hydraulic pressure.
Initial oil pressure = reference oil pressure + correction value A

  In this case, the initial hydraulic pressure is a hydraulic pressure obtained by adding the absolute value of the correction value A to the previous learned value of the reference hydraulic pressure when the correction value A is a positive value, and the previous learned value of the reference hydraulic pressure when the correction value A is a negative value. The hydraulic pressure is obtained by subtracting the absolute value of the correction value A.

  Thereafter, the engagement command of the engagement side clutch is gradually decreased by decreasing the hydraulic pressure command value of the engagement side clutch from the initial hydraulic pressure with a constant gradient and decreasing the hydraulic pressure applied to the engagement side clutch with a constant gradient. Let

  Thereafter, at a time point t3 when a predetermined hydraulic pressure learning condition is satisfied, the clutch output side rotational speed (the rotational speed obtained by multiplying the output shaft rotational speed No of the transmission gear mechanism 15 by the speed ratio of the first speed that is the gear stage at the start of the vehicle). ) And the input shaft rotational speed Nt is started to determine whether or not the rotational speed difference ΔN is greater than or equal to the learning determination value, and the rotational speed difference ΔN between the clutch output side rotational speed and the input shaft rotational speed Nt is learned. It is determined that the engagement side clutch has started slipping at time t4 when the value becomes equal to or greater than the determination value, and the hydraulic pressure at that time (for example, the hydraulic pressure command value of the engagement side clutch) is used as a reference hydraulic pressure (hydraulic pressure at which the engagement side clutch starts to slide) To learn as.

Thereafter, a hydraulic pressure obtained by subtracting and correcting the correction value B (second correction value) from the learning value of the reference hydraulic pressure (for example, the reference hydraulic pressure learned during the current pressure reduction control ) is set as the final hydraulic pressure of the pressure reduction control. By setting the oil pressure command value of the engagement side clutch to the final oil pressure, the engagement side clutch is released. Final oil pressure = Reference oil pressure-Correction value B

Thereafter, at the time t5 when the engine restart condition is satisfied, the fuel injection of the engine is restarted to automatically restart the engine, and the engagement side clutch pressure increase control is executed. In this pressure increase control, first, an oil pressure obtained by subtracting and correcting a correction value C (third correction value) from a learning value of a reference oil pressure (for example, a reference oil pressure learned during the current pressure reduction control ) is an initial oil pressure for pressure increase control. By setting the hydraulic pressure command value of the engagement side clutch to the initial hydraulic pressure, the engagement side clutch is brought into a semi-engagement state.
Initial oil pressure = reference oil pressure−correction value C

  Thereafter, at the time t6 when the engine restart is completed, the hydraulic pressure command value of the engagement side clutch is increased from the initial hydraulic pressure with a constant gradient, and the hydraulic pressure applied to the engagement side clutch is increased with a constant gradient. The engagement force of the engagement side clutch is gradually increased.

  Thereafter, at time t7 when the input shaft rotational speed Nt of the transmission gear mechanism 15 starts to decrease, the vehicle is set to the target synchronous rotational speed (the output shaft rotational speed No of the transmission gear mechanism 15). F / B control is performed to control the hydraulic pressure command value of the engagement side clutch so as to coincide with the rotation speed multiplied by the speed ratio of the first speed, which is the speed stage at the time of start, and the first speed ratio is established. At time t8, control for increasing the hydraulic pressure command value of the engagement side clutch to the maximum pressure is executed.

  The idling stop control and clutch hydraulic pressure control (pressure reduction control and pressure increase control) according to the present embodiment described above are executed by the AT-ECU 30 and / or the engine control device 37 according to the routines shown in FIGS. Hereinafter, the processing content of each of these routines will be described.

[Fuel cut control routine]
The fuel cut control routine shown in FIG. 5 is repeatedly executed at a predetermined cycle during the power-on period of the AT-ECU 30 and the engine control device 37 (while the ignition switch is on). When this routine is started, first, in step 101, it is determined based on an output signal of an accelerator sensor (not shown) whether or not the accelerator is OFF (the accelerator operation is not performed).

  If it is determined in step 101 that the accelerator is OFF, the process proceeds to step 102 where it is determined whether or not the engine speed detected by the engine speed sensor 27 is equal to or greater than a predetermined value. If it is determined that the value is equal to or greater than the predetermined value, the process proceeds to step 105 to perform fuel cut.

  On the other hand, if it is determined in step 102 that the engine speed is lower than the predetermined value, the process proceeds to step 103, and an engine automatic stop condition determination routine shown in FIG. A process of determining whether or not it is established is performed.

  Thereafter, the process proceeds to step 104, where it is determined whether or not the engine automatic stop condition is satisfied based on the determination result of the engine automatic stop condition determination process (step 103), and the engine automatic stop condition is satisfied. If it is determined, the routine proceeds to step 106 where fuel cut is performed to automatically stop the combustion of the engine.

  On the other hand, if it is determined in step 103 that the engine automatic stop condition is not satisfied, the routine proceeds to step 107, where fuel cut is stopped and fuel injection is restarted. If it is determined in step 101 that the accelerator is ON (accelerator operation is in progress), the routine proceeds to step 108, where fuel cut is stopped and fuel injection is restarted.

[Engine automatic stop condition judgment routine]
The engine automatic stop condition determination routine shown in FIG. 6 is a subroutine executed in step 103 of the fuel cut control routine of FIG. When this routine is started, first, in step 201, it is determined whether or not the vehicle speed detected by a vehicle speed sensor (not shown) is equal to or less than a predetermined value.

  If it is determined in step 201 that the vehicle speed is equal to or lower than the predetermined value, the process proceeds to step 202, and whether or not the brake is ON (braking operation) based on an output signal of a brake switch (not shown). Determine.

  If it is determined in step 201 that the vehicle speed is equal to or lower than the predetermined value, and it is determined in step 202 that the brake is ON, the process proceeds to step 203 and it is determined that the engine automatic stop condition is satisfied. .

  On the other hand, if it is determined in step 201 that the vehicle speed is higher than the predetermined value, or if it is determined in step 202 that the brake is OFF (a state where the brake operation is not performed), step 204 is performed. It proceeds and determines that the engine automatic stop condition is not satisfied.

[Starter control routine]
The starter control routine shown in FIG. 7 is repeatedly executed at a predetermined cycle during the power-on period of the AT-ECU 30 and the engine control device 37. When this routine is started, first, at step 301, it is determined whether or not it is a manual start when the driver operates an ignition switch (not shown) to start the engine. If it is determined, the routine proceeds to step 304, where the starter (not shown) is driven to rotationally drive (crank) the crankshaft of the engine to start the engine.

  On the other hand, if it is determined in step 301 that it is not at the time of manual start, the routine proceeds to step 302, where the fuel injection is restarted from the fuel cut state and the engine is started (at the time of restart). If it is not at the time of automatic start, this routine is terminated as it is.

  On the other hand, if it is determined in step 302 that the automatic start is in progress, the process proceeds to step 303, and it is determined whether or not it is difficult to start the engine in the starterless start only by fuel injection. For example, if the engine stop position (engine start position) is not within a predetermined crank angle range suitable for starterless start, it is determined that it is difficult to start only with fuel injection. If the cooling water temperature is equal to or lower than the predetermined temperature, it is determined that the engine friction during cranking is large and it is difficult to start only with fuel injection.

  If it is determined in this step 303 that it is difficult to start only with fuel injection, the routine proceeds to step 304, where the starter is driven to rotate the crankshaft of the engine to start the engine. On the other hand, if it is determined in step 303 that the engine can be started only by fuel injection (starterless start is possible), this routine is immediately terminated. In this case, starterless start with only fuel injection is executed.

[Clutch hydraulic control routine]
The clutch hydraulic pressure control routine shown in FIG. 8 is repeatedly executed at a predetermined cycle during the power-on period of the AT-ECU 30 and the engine control device 37. When this routine is started, first, in step 401, it is determined whether or not it is an automatic start time (restart time) in which fuel injection is restarted from the fuel cut state and the engine is started.

  If it is determined in step 401 that the automatic start is not in progress, the process proceeds to step 402, where it is determined whether or not the fuel is being cut (combustion is stopped), and if it is determined that the fuel is not being cut. In this case, this routine is finished as it is.

  On the other hand, if it is determined in step 402 that the fuel cut is in progress, the process proceeds to step 403 to determine whether the decompression control start condition is satisfied, for example, whether the vehicle speed is equal to or lower than a predetermined value, This routine is finished as it is when it is determined whether or not a predetermined time or more has passed since the start of fuel cut, and it is determined that the decompression control start condition is not satisfied.

  Thereafter, if it is determined in step 403 that the decompression control start condition is satisfied, the process proceeds to step 404, and a decompression control routine shown in FIG. Pressure reduction control is performed to reduce the hydraulic pressure applied to the engagement-side clutch (for example, the clutch LC) of the gear mechanism 15 so that the engagement-side clutch is released.

  Thereafter, if it is determined in step 401 that the engine is being automatically started (restarted), the process proceeds to step 405 to execute a pressure increase control routine in FIG. Pressure increase control is executed to return the engagement side clutch to the engaged state after increasing the hydraulic pressure applied to the engagement side clutch (for example, the clutch LC) to bring the engagement side clutch into the half-engaged state (slip state).

[Decompression control routine]
The decompression control routine shown in FIG. 9 is a subroutine executed in step 404 of the clutch hydraulic pressure control routine in FIG. 8, and serves as decompression control means in the claims. When this routine is started, first, in step 501, the current pressure reduction control stage is determined based on whether the value of the control stage flag FlagN_G for determining the pressure reduction control stage is 0 to 3.

  Since the control stage flag FlagN_G is set to the initial value “0” at the time of starting the pressure reduction control, the process proceeds to step 502 and the learning value of the reference oil pressure (for example, the reference oil pressure learned during the previous pressure reduction control) is set. After reading, the process proceeds to step 503, and the vehicle speed and oil temperature at the time of the previous learning (for example, when the reference hydraulic pressure is learned during the previous pressure reduction control) are read.

  Thereafter, the process proceeds to step 504, where the difference between the vehicle speed at the previous learning and the current vehicle speed is calculated, and the difference between the oil temperature at the previous learning and the current oil temperature is calculated. Then, the process proceeds to step 505, where the reference A correction value A for calculating the initial hydraulic pressure for pressure reduction control is calculated based on the learned hydraulic pressure value.

In this case, referring to the map of the correction value A1 shown in FIG. 12 (a), the correction value A1 corresponding to the difference between the vehicle speed at the previous learning and the current vehicle speed is calculated, and shown in FIG. 12 (b). The correction value A2 is calculated from the correction value A1 and the correction value A2 after calculating the correction value A2 according to the difference between the oil temperature at the previous learning and the current oil temperature with reference to the map of the correction value A2.
Correction value A = correction value A1 + correction value A2

  The map of the correction value A1 shown in FIG. 12A is set so that the correction value A1 increases as the difference between the vehicle speed at the previous learning and the current vehicle speed increases, and the correction value A2 shown in FIG. This map is set so that the correction value A2 increases as the difference between the oil temperature at the previous learning and the current oil temperature increases. The map of the correction value A1 and the map of the correction value A2 are created in advance based on test data, design data, and the like, respectively, and stored in the ROM of the AT-ECU 30 or the engine control device 37.

  Here, the output shaft rotational speed No of the transmission gear mechanism 15 changes according to the vehicle speed, and the hydraulic pressure at which the engagement side clutch begins to slide changes, and the fluidity of the hydraulic oil changes according to the oil temperature to engage. Since the hydraulic pressure at which the side clutch starts to slide changes, the actual reference hydraulic pressure (hydraulic pressure at which the engagement side clutch starts to slide) changes according to the vehicle speed and the oil temperature at that time.

  In consideration of such circumstances, in this routine, by calculating the correction value A based on the vehicle speed and the oil temperature, the reference oil pressure (the oil pressure at which the engaging clutch starts to slide) changes according to the vehicle speed and the oil temperature. Corresponding to this, the correction value A can be changed to set the initial hydraulic pressure of the pressure reduction control to an appropriate value.

  In this routine, the correction value A1 corresponding to the vehicle speed and the correction value A2 corresponding to the oil temperature are calculated separately, and the correction value A is calculated from the correction value A1 and the correction value A2. For example, the correction value A corresponding to the vehicle speed and the oil temperature may be directly calculated using a map of the correction value A that parameters the vehicle speed and the oil temperature.

Thereafter, the process proceeds to step 506, where the hydraulic pressure corrected by the correction value A with respect to the learned value of the reference hydraulic pressure (for example, the reference hydraulic pressure learned during the previous decompression control) is set as the initial hydraulic pressure of the decompression control, and the engagement side The hydraulic pressure command value of the clutch (for example, clutch LC) is set to the initial hydraulic pressure.
Initial oil pressure = reference oil pressure + correction value A

  In this case, the initial hydraulic pressure is a hydraulic pressure obtained by adding the absolute value of the correction value A to the previous learned value of the reference hydraulic pressure when the correction value A is a positive value, and the previous learned value of the reference hydraulic pressure when the correction value A is a negative value. The hydraulic pressure is obtained by subtracting the absolute value of the correction value A.

  As a result, the initial hydraulic pressure of the pressure reduction control can be set by appropriately correcting the previous learned value of the reference hydraulic pressure, and the hydraulic pressure applied to the engaging clutch during the pressure reduction control can be reduced from this initial hydraulic pressure. By doing so, it is possible to learn the reference oil pressure reliably and promptly during the pressure reduction control.

  Thereafter, the process proceeds to step 507, where the control stage flag FlagN_G is set to “1”, and this routine is terminated.

  If the control stage flag FlagN_G is set to “1” in step 507, the process proceeds from step 501 to step 508 at the next activation of this routine to determine whether or not the vehicle speed is equal to or lower than a predetermined value. If it is determined that the vehicle speed is higher than the predetermined value, the process proceeds to step 509, and this routine is terminated while the control stage flag FlagN_G is maintained at “1”.

  Thereafter, when it is determined in step 508 that the vehicle speed is equal to or lower than the predetermined value, the process proceeds to step 510, the control stage flag FlagN_G is set to “2”, and this routine is terminated.

  If the control stage flag FlagN_G is set to “2” in step 510, the next step of starting this routine proceeds from step 501 to step 511, where the engagement side clutch hydraulic pressure command value is kept constant from the initial hydraulic pressure. The hydraulic pressure applied to the engaging clutch is decreased at a constant gradient by decreasing the gradient. Thereby, the engagement force of the engagement side clutch is gradually decreased.

  Thereafter, the process proceeds to step 512, where the clutch output side rotational speed (the rotational speed obtained by multiplying the output shaft rotational speed No of the transmission gear mechanism 15 by the speed ratio of the first speed, which is the gear stage at the start of the vehicle), and the input shaft rotational speed. A rotational speed difference ΔN with Nt is calculated.

  Thereafter, the process proceeds to step 513, where a later-described oil pressure learning condition determination routine of FIG. 10 is executed to determine whether or not the oil pressure learning condition is satisfied. Thereafter, the process proceeds to step 514, where it is determined whether the oil pressure learning condition is satisfied based on the determination result of the oil pressure learning condition determination process (step 513), and it is determined that the oil pressure learning condition is satisfied. In this case, the process proceeds to step 515, and it is determined whether or not the rotational speed difference ΔN between the clutch output side rotational speed and the input shaft rotational speed Nt is equal to or greater than the learning determination value.

  If it is determined in step 515 that the rotational speed difference ΔN between the clutch output side rotational speed and the input shaft rotational speed Nt is smaller than the learning determination value, the process proceeds to step 516, and the control stage flag FlagN_G is set to “2”. This routine is terminated while maintaining the above.

  Thereafter, when it is determined in step 515 that the rotational speed difference ΔN between the clutch output side rotational speed and the input shaft rotational speed Nt is greater than or equal to the learning determination value, it is determined that the engagement side clutch has started to slip, Proceeding to step 517, the oil pressure at that time (for example, the oil pressure command value of the engagement side clutch) is learned as the reference oil pressure (the oil pressure at which the engagement side clutch starts to slide), and the vehicle speed and oil temperature at the time of learning of this reference oil pressure are determined. get. The learning value of the reference oil pressure, the vehicle speed, and the oil temperature are stored in a rewritable nonvolatile memory such as a backup RAM (not shown) of the AT-ECU 30 or the engine control device 37 (a rewritable memory that holds stored data even when the power is off). ). The processing of these steps 512 to 517 serves as a hydraulic pressure learning means in the claims.

Thereafter, the process proceeds to step 518, the control stage flag FlagN_G is set to “3”, and this routine is finished.
On the other hand, if it is determined in step 514 that the hydraulic pressure learning condition is not satisfied, the process proceeds to step 519, where it is determined whether the vehicle speed is equal to or less than a predetermined value (for example, a lower limit side threshold value described later). Is determined to be higher than the predetermined value, it is determined that there is a possibility that the hydraulic pressure learning condition may be satisfied, and the process proceeds to step 520 and the routine is performed while the control stage flag FlagN_G is maintained at “2”. finish.

  On the other hand, if it is determined in step 519 that the vehicle speed is equal to or lower than the predetermined value, it is determined that there is no possibility that the hydraulic pressure learning condition is satisfied, the process proceeds to step 521, and the control stage flag FlagN_G is set. Set to “3” and the routine is terminated.

  If the control stage flag FlagN_G is set to “3” in step 518 or step 521, the process proceeds from step 501 to step 522 at the next activation of this routine, and the learning value of the reference oil pressure (for example, this time) After reading the reference oil pressure learned during the pressure reduction control, the process proceeds to step 523, where a correction value B for calculating the final oil pressure of the pressure reduction control is calculated based on the learned value of the reference oil pressure.

In this case, the correction value B1 corresponding to the current vehicle speed is calculated with reference to the correction value B1 map shown in FIG. 13A, and the correction value B2 map shown in FIG. 13B is referred to. After calculating the correction value B2 corresponding to the current oil temperature, the correction value B2 is obtained by adding the correction value B2 to the correction value B1.
Correction value B = correction value B1 + correction value B2

  The map of the correction value B1 shown in FIG. 13A is set so that the correction value B1 increases as the vehicle speed increases. The map of the correction value B2 shown in FIG. 13B shows the correction value as the oil temperature increases. B2 is set to be small. The map of the correction value B1 and the map of the correction value B2 are created in advance based on test data, design data, and the like, respectively, and stored in the AT-ECU 30 or the ROM of the engine control device 37.

  In this routine, the correction value B is calculated based on the vehicle speed and the oil temperature, so that the correction value corresponds to the change in the reference oil pressure (the oil pressure at which the engaging clutch starts to slide) according to the vehicle speed and the oil temperature. By changing B, the final hydraulic pressure of the pressure reduction control can be set to an appropriate value.

  In this routine, the correction value B1 corresponding to the vehicle speed and the correction value B2 corresponding to the oil temperature are separately calculated, and the correction value B is calculated from the correction value B1 and the correction value B2. For example, the correction value B corresponding to the vehicle speed and the oil temperature may be directly calculated using a map of the correction value B that parameters the vehicle speed and the oil temperature.

Thereafter, the process proceeds to step 524, in which the hydraulic pressure that is lower than the learned value of the reference hydraulic pressure (for example, the reference hydraulic pressure learned during the current decompression control) by the correction value B is set as the final hydraulic pressure of the decompression control, and the engagement side clutch Is set to the final hydraulic pressure.
Final oil pressure = Reference oil pressure-Correction value B

  Accordingly, the final hydraulic pressure of the pressure reduction control can be set to a hydraulic pressure that is appropriately lower than the reference hydraulic pressure so as to disengage the engagement side clutch, and the hydraulic pressure that is applied to the engagement side clutch during the pressure reduction control. By controlling to the final hydraulic pressure, the engagement side clutch can be surely and quickly released.

[Hydraulic learning condition judgment routine]
Hydraulic learning condition determination routine shown in FIG. 10, the Ri subroutine der executed in step 513 of the pressure reduction control routine of Figure 9, serve as a learning execution condition determining means in the claims. When this routine is started, first, in steps 601 and 602, it is determined whether or not the vehicle speed is within a predetermined range (lower threshold value ≦ vehicle speed ≦ upper threshold value), and it is determined that the vehicle speed is within the predetermined range. Then, in the next steps 603 and 604, it is determined whether or not the oil temperature is within a predetermined range (lower limit side threshold ≦ oil temperature ≦ upper limit threshold).

  As a result, when it is determined in 601 and 602 that the vehicle speed is within the predetermined range, and in steps 603 and 604, the oil temperature is determined to be within the predetermined range, the reference hydraulic pressure can be learned accurately. In step 605, it is determined that the hydraulic pressure learning condition is satisfied.

  On the other hand, when it is determined in 601 and 602 that the vehicle speed is outside the predetermined range (the vehicle speed is higher than the upper threshold value or the vehicle speed is lower than the lower threshold value), or in steps 603 and 604 described above. If it is determined that the oil temperature is outside the predetermined range (the oil temperature is higher than the upper threshold value or the oil temperature is lower than the lower threshold value), it is determined that there is a possibility that the reference oil pressure may not be learned accurately. In step 606, it is determined that the hydraulic pressure learning condition is not satisfied.

[Pressure increase control routine]
The pressure increase control routine shown in FIG. 11 is a subroutine executed in step 405 of the clutch hydraulic pressure control routine shown in FIG. 8, and serves as pressure increase control means in the claims. When this routine is started, first, in step 701, the current stage of pressure increase control is determined based on whether the value of the control stage flag FlagN_K for determining the stage of pressure increase control is 0 to 3. To do.

  Since the control stage flag FlagN_K is set to the initial value “0” at the time of starting the pressure increase control, the process proceeds to step 702 and the learning value of the reference oil pressure (for example, the reference oil pressure learned during the current pressure reduction control). Then, the process proceeds to step 703, where a correction value C for calculating the initial oil pressure of the pressure increase control is calculated based on the learning value of the reference oil pressure.

In this case, the correction value C1 corresponding to the current vehicle speed is calculated with reference to the correction value C1 map shown in FIG. 14A, and the correction value C2 map shown in FIG. 14B is referred to. After calculating the correction value C2 corresponding to the current oil temperature, the correction value C2 is obtained by adding the correction value C2 to the correction value C1.
Correction value C = correction value C1 + correction value C2

  The map of the correction value C1 shown in FIG. 14A is set so that the correction value C1 increases as the vehicle speed increases. The map of the correction value C2 shown in FIG. 14B shows the correction value as the oil temperature increases. A2 is set to be small. The map of the correction value C1 and the map of the correction value C2 are created in advance based on test data, design data, and the like, respectively, and are stored in the ROM of the AT-ECU 30 or the engine control device 37.

  In this routine, the correction value C is calculated based on the vehicle speed and the oil temperature, so that the correction value C corresponds to the change in the reference oil pressure (the oil pressure at which the engaging clutch starts to slide) according to the vehicle speed and the oil temperature. By changing C, the initial hydraulic pressure for pressure increase control can be set to an appropriate value.

  In this routine, the correction value C1 corresponding to the vehicle speed and the correction value C2 corresponding to the oil temperature are calculated separately, and the correction value C is calculated from the correction value C1 and the correction value C2. For example, the correction value C corresponding to the vehicle speed and the oil temperature may be directly calculated using a map of the correction value C that parameters the vehicle speed and the oil temperature.

Thereafter, the process proceeds to step 704, where a hydraulic pressure that is lower than the learned value of the reference hydraulic pressure (for example, the reference hydraulic pressure learned during the current pressure reduction control) by the correction value C is set as the initial hydraulic pressure for the pressure increase control. The hydraulic pressure command value of the clutch (for example, clutch LC) is set to the initial hydraulic pressure.
Initial oil pressure = reference oil pressure−correction value C

  As a result, the initial hydraulic pressure of the pressure increase control can be set slightly lower than the reference hydraulic pressure to set the engagement side clutch to a half-engaged state (slip state). By controlling the hydraulic pressure applied to the engagement clutch to the initial hydraulic pressure, the engagement clutch can be surely and quickly brought into the semi-engagement state.

  Thereafter, the process proceeds to step 705, where it is determined whether or not the engine rotational speed is equal to or higher than a predetermined value (complete explosion determination value). When it is determined that the engine rotational speed is equal to or higher than the predetermined value, the engine is restarted. Is completed, the process proceeds to step 706, the control stage flag FlagN_K is set to “1”, and this routine ends.

  If the control stage flag FlagN_K is set to “1” in step 706, the process proceeds from step 701 to step 707 at the next activation of this routine, and the hydraulic pressure command value of the engagement side clutch is made constant from the initial hydraulic pressure. The hydraulic pressure applied to the engaging clutch is increased at a constant gradient by increasing the gradient. Thereby, the engagement force of the engagement side clutch is gradually increased. When the hydraulic pressure of the engagement side clutch increases and the engagement force of the engagement side clutch increases to some extent, the input shaft rotational speed Nt of the transmission gear mechanism 15 starts to decrease.

  Thereafter, the process proceeds to step 708, where it is determined whether or not the input shaft rotation speed Nt of the transmission gear mechanism 15 has started to decrease, and if it is determined that the input shaft rotation speed Nt of the transmission gear mechanism 15 has not decreased, Proceeding to step 709, the present routine is terminated while the control stage flag FlagN_K is maintained at "1".

  Thereafter, when it is determined in step 708 that the input shaft rotational speed Nt of the transmission gear mechanism 15 has started to decrease, the process proceeds to step 710, the control stage flag FlagN_K is set to “2”, and this routine is terminated. To do.

  If the control stage flag FlagN_K is set to “2” in step 710, the process proceeds from step 701 to step 711 at the next activation of this routine, and the input shaft rotation speed Nt of the transmission gear mechanism 15 is set to the target synchronization. F for controlling the hydraulic pressure command value of the engagement side clutch so as to coincide with the rotational speed (the rotational speed obtained by multiplying the output shaft rotational speed No of the transmission gear mechanism 15 by the speed ratio of the first speed, which is the shift stage at the start of the vehicle). / B control is executed.

  Thereafter, the process proceeds to step 712 to determine whether or not the first gear ratio has been established, for example, whether the rotational speed difference between the input shaft rotational speed Nt of the transmission gear mechanism 15 and the target synchronous rotational speed is equal to or smaller than a determination value. It is determined by whether or not it has continued for a predetermined time. When it is determined that the first gear ratio has been established, the routine proceeds to step 713, the control stage flag FlagN_K is set to “3”, and this routine is terminated. .

  If the control stage flag FlagN_K is set to “3” in the above step 713, the process proceeds from step 701 to step 714 at the next activation of this routine, and the hydraulic pressure command value of the engaging clutch is increased to the maximum pressure. The control is executed to increase the hydraulic pressure of the engaging clutch to the maximum pressure, and then the process proceeds to step 715 to reset the control stage flag FlagN_K of the pressure increase control to the initial value “0”, and to the next step 716 Then, the control stage flag FlagN_G of the pressure reduction control is reset to the initial value “0”, and this routine is finished.

  In the present embodiment described above, during the fuel cut of the engine (when the combustion is stopped), the pressure reduction control for reducing the hydraulic pressure applied to the engagement side clutch of the transmission gear mechanism 15 and releasing the engagement side clutch is executed. After that, when the engine is restarted, the hydraulic pressure applied to the engagement side clutch is increased to bring the engagement side clutch into the semi-engagement state (slip state), and then the pressure increase control to return the engagement side clutch to the engagement state. Therefore, when the engine is restarted, it is possible to suppress the transmission of the engine starting torque to the wheel side via the transmission gear mechanism 15 by setting the engagement side clutch in the half-engaged state. It is possible to prevent unpleasant shocks from occurring.

  Further, during the pressure reduction control, the reference hydraulic pressure (engagement) is determined based on the rotational speed difference ΔN between the clutch output side rotational speed (the rotational speed obtained by multiplying the output shaft rotational speed No by the first gear ratio) and the input shaft rotational speed Nt. The system is manufactured because the hydraulic pressure applied to the engaging clutch is controlled based on the learning value of the reference hydraulic pressure during pressure reduction control and pressure increase control. Even if the operating characteristics of the engagement side clutch with respect to the hydraulic pressure change due to variations, changes over time, etc., the hydraulic pressure applied to the engagement side clutch during pressure reduction control and pressure increase control is appropriately controlled without being affected by it. Can do. Accordingly, the vehicle can be started or accelerated promptly after restarting while preventing an unpleasant shock from occurring when the engine is restarted.

  In the above embodiment, when the rotational speed difference ΔN between the clutch output side rotational speed (the rotational speed obtained by multiplying the output shaft rotational speed No by the first gear ratio) and the input shaft rotational speed Nt becomes a predetermined value or more. In addition, it is determined that the engagement-side clutch has started to slip, and the oil pressure at that time is learned as the reference oil pressure. However, the present invention is not limited to this, and is obtained from, for example, the input shaft rotation speed Nt and the output shaft rotation speed No. When the transmission gear ratio becomes equal to or greater than a predetermined value, it may be determined that the engagement-side clutch has started to slip, and the oil pressure at that time may be learned as the reference oil pressure.

  In addition, the present invention is not limited to the above-described embodiments. For example, the configuration of the transmission gear mechanism 15, the number of shift stages, the relationship between engagement / release of friction engagement elements and the shift stages, and the like may be changed as appropriate. Various modifications can be made without departing from the spirit of the invention.

  In addition, the present invention is not limited to a stepped transmission that switches gears (speed ratios) in stages, and may be applied to a continuously variable transmission (CVT) that changes continuously.

DESCRIPTION OF SYMBOLS 11 ... Automatic transmission, 12 ... Torque converter, 15 ... Transmission gear mechanism (transmission mechanism), 16 ... Lock-up clutch, 17 ... Hydraulic control circuit, 18 ... Engine-driven hydraulic pump, 20 ... Automatic transmission control circuit, 24 DESCRIPTION OF SYMBOLS ... Electric hydraulic pump, 25 ... Shift lever, 27 ... Engine rotation speed sensor, 28 ... Input shaft rotation speed sensor, 29 ... Output shaft rotation speed sensor, 30 ... AT-ECU (shift control means, pressure reduction control means, increase Pressure control means, learning execution condition determination means, hydraulic pressure learning means), 37 ... engine control device (idling stop control means), RC, HC, LC ... clutch (friction engagement element), B0, B1 ... brake (friction engagement) element)

Claims (3)

This is applied to a vehicle that transmits the power of the internal combustion engine to the wheel side via the speed change mechanism, and continuously controls the power transmission of the speed change mechanism by controlling the hydraulic pressure applied to the friction engagement element provided in the speed change mechanism. Control of a vehicle provided with idling stop control means for intermittently stopping and stopping the combustion of the internal combustion engine when a predetermined automatic stop condition is satisfied and restarting the internal combustion engine when a predetermined restart condition is satisfied In the device
Pressure reduction control means for executing pressure reduction control to reduce the hydraulic pressure applied to the frictional engagement element on the engagement side of the speed change mechanism while the combustion of the internal combustion engine is stopped, so that the frictional engagement element on the engagement side is released. When,
The engagement-side frictional engagement element after the hydraulic pressure applied to the engagement-side frictional engagement element at the time of restarting the internal combustion engine is increased to bring the engagement-side frictional engagement element into a semi-engaged state. Pressure-increasing control means for executing pressure-increasing control for bringing
While the combustion of the internal combustion engine is stopped, it is determined whether the vehicle speed is within a predetermined range indicating that the vehicle is decelerating, it is determined whether the oil temperature is within a predetermined range, the vehicle speed is determined to be within the predetermined range, and the oil temperature is Learning execution condition determination means for determining that the hydraulic pressure learning execution condition is satisfied when it is determined that the pressure is within the predetermined range;
When the learning execution condition determining means determines that the hydraulic pressure learning execution condition is satisfied, calculation of the rotational speed difference between the output side rotational speed of the transmission mechanism and the input shaft rotational speed is started, and the rotational speed hydraulic difference of learning as a hydraulic (hereinafter referred to as "reference oil") for the hydraulic pressure command value of the frictional engagement element on the engagement side starts slipping frictional engagement elements of the engagement side when it is more than learning determination value Learning means,
The vehicle pressure reduction control means and the pressure increase control means control a hydraulic pressure applied to the engagement frictional engagement element based on a learning value of a reference hydraulic pressure learned by the hydraulic pressure learning means. Control device. The pressure reduction control means sets the hydraulic pressure obtained by adding and correcting the first correction value to the learning value of the reference hydraulic pressure as the initial hydraulic pressure of the pressure reduction control when the pressure reduction control start condition is satisfied after the automatic stop condition is satisfied. And, after the reference oil pressure is learned by the oil pressure learning means, a hydraulic pressure obtained by subtracting and correcting a second correction value from the learned value of the reference oil pressure is set as a final oil pressure for the pressure reduction control, and the pressure increase control The means sets an oil pressure obtained by subtracting and correcting a third correction value from a learning value of the reference oil pressure as an initial oil pressure for pressure increase control when the restart condition is satisfied. The vehicle control device described. The decompression control means calculates the first correction value and the second correction value based on a vehicle speed and an oil temperature ,
3. The vehicle control device according to claim 2 , wherein the pressure increase control unit calculates the third correction value based on a vehicle speed and an oil temperature .

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