JP6794015B2 - Vehicle control device - Google Patents

Description

The present invention relates to a control device used in a vehicle equipped with a continuously variable transmission.

In vehicles such as automobiles, the power from the drive source is input to the input shaft of the transmission, and the power shifted by the transmission is transmitted from the output shaft to the drive wheels via the differential gear or the like.

A continuously variable transmission (CVT) is known as a transmission mounted on a vehicle. The belt-type continuously variable transmission is an example of a continuously variable transmission, and has a configuration in which an endless belt is wound around a primary pulley on the input side and a secondary pulley on the output side. Each pulley of the primary pulley and the secondary pulley includes a fixed sheave and a movable sheave that faces the fixed sheave with a belt sandwiched between them and can move in the opposite direction (rotational axis direction). By changing the distance between the fixed sheave and the movable sheave in each pulley, the winding diameter of the belt for each pulley can be changed, and the gear ratio (pulley ratio) can be continuously changed steplessly.

In order to switch between forward and reverse of the vehicle, the continuously variable transmission is provided with a planetary gear (planetary gear mechanism) as a forward / backward switching mechanism. The planetary gear is provided between the input shaft and the primary shaft that supports the primary pulley, or between the secondary shaft that supports the secondary pulley and the output shaft.

In a configuration in which the planetary gear is provided between the secondary shaft and the output shaft, for example, the secondary shaft and the sun gear of the planetary gear are integrally rotatably connected, and the output shaft and the ring gear of the planetary gear are integrally rotatably connected. ing. The carrier of the planetary gear is provided so as to be rotatable relative to the secondary shaft. When the vehicle moves forward, the carrier is put into a free rotation state, and the sun gear and the ring gear are directly connected. As a result, the power transmitted to the secondary shaft causes the sun gear and the ring gear to rotate integrally, and the output shaft to rotate integrally with the ring gear. On the other hand, when the vehicle is moving backward (backward), the direct connection between the sun gear and the ring gear is released, and the carrier is fixed so as not to rotate. As a result, when the sun gear rotates integrally with the secondary shaft, the ring gear rotates in the direction opposite to that of the sun gear, and the output shaft rotates integrally with the ring gear in the direction opposite to that when the vehicle is moving forward. At this time, due to the configuration of the planetary gear, the rotation speed of the ring gear (output shaft) is always lower than the rotation speed of the sun gear.

Therefore, the maximum gear ratio when moving backward is larger than the maximum gear ratio when moving forward, and if the magnitude of the power input to the input shaft is the same, the output shaft when moving backward is compared with when moving forward. The driving force output to is increased. In this configuration where the difference in driving force between forward and reverse is large, there is a concern that the vehicle may pop out due to creep when the brakes are released, and a grown noise (brake noise) may occur due to insufficient braking force, especially when moving backward. Considerable ingenuity is required to control the transmission.

Japanese Unexamined Patent Publication No. 2004-176890

An object of the present invention is to provide a vehicle control device capable of dispelling various concerns in a configuration in which a driving force difference between a vehicle moving forward and backward is large.

In order to achieve the above object, the vehicle control device according to the present invention transmits power to a primary pulley and a secondary pulley on a power transmission path from an input shaft in which engine power is input to an output shaft in which power is output. A planetary gear equipped with a belt-type continuously variable transmission mechanism that shifts steplessly by changing the pulley ratio, a sun gear that can rotate integrally with the carrier and secondary pulley, and a ring gear that can rotate integrally with the output shaft. A mechanism is provided, the carrier is put into a free rotation state in the forward range, the sun gear and the ring gear are directly connected, the direct connection between the sun gear and the ring gear is released in the reverse range, and the carrier is fixed non-rotatably. A control device used for vehicles equipped with a transmission, a pulley ratio changing means for changing the pulley ratio of a continuously variable transmission mechanism to a target pulley ratio, and an idle high rotation speed in which the idle speed of the engine is higher than a predetermined speed. In the state, the pulley ratio limiting means for limiting the upper limit of the target pulley ratio to a pulley ratio smaller than the maximum pulley ratio of the continuously variable transmission mechanism according to the idle high rotation state is included.

Due to its configuration, the continuously variable transmission mounted on the vehicle in which the vehicle control device according to the present invention is used has a constant forward range and reverse movement, with the power input to the input shaft and the pulley ratio of the continuously variable transmission mechanism being constant. Compared with the range, the maximum gear ratio is larger in the reverse range than in the forward range, and therefore the driving force output to the output shaft is larger in the reverse range than in the forward range. Therefore, the idle speed of the engine of the vehicle is higher than the predetermined speed (for example, the engine speed when the device that loads the engine such as the air conditioner is not operating and the engine is sufficiently warmed up). In the high rotation speed state, the creep torque during idle rotation of the engine becomes excessive when the vehicle is moving backward.

Therefore, in the idle high rotation state, when the pulley ratio is changed to the target pulley ratio, the upper limit of the target pulley ratio is smaller than the maximum pulley ratio, and the pulley ratio is limited according to the idle high rotation state. To. As a result, the pulley ratio while the vehicle is stopped can be limited to a pulley ratio smaller than the maximum pulley ratio. Therefore, the creep torque at the time of starting the vehicle can be suppressed. In particular, it is possible to prevent the creep torque from becoming excessive when the vehicle starts in the reverse direction, and it is possible to eliminate concerns such as popping out due to creep when the vehicle brake is released and generation of grown noise due to insufficient braking force. ..

Whether or not the engine is in a high idle speed state may be determined by acquiring the idle speed of the engine and comparing the acquired idle speed with a predetermined speed. In this case, the pulley ratio according to the idle high rotation state may be the pulley ratio according to the difference between the idle rotation speed and the predetermined rotation speed.

Further, a numerical value or an event having a correlation with the high or low idle speed may be detected, and the idle high speed state may be determined based on the detection.

A numerical value that correlates with the high and low idle speeds is, for example, the water temperature of the engine, and even if the state detecting means detects the water temperature and determines that the water temperature is lower than a predetermined temperature, it is determined to be in a high idle speed state. Good.

An event that correlates with the high and low idle speeds is, for example, the on / off of the air conditioner of the vehicle, the on / off of the air conditioner is detected, and the high idle speed occurs when the air conditioner is on. It may be determined as a state.

According to the present invention, since the creep torque when the vehicle starts can be suppressed, the vehicle jumps out due to creep when the brake is released, and a grown sound is generated due to insufficient braking force. Various concerns can be dispelled in configurations with large driving force differences.

It is a figure which shows the structure of the main part of the vehicle which mounted the control device which concerns on one Embodiment of this invention. It is a skeleton diagram which shows the structure of the drive system of a vehicle. It is a figure which shows the state of the engaging element included in the power split type continuously variable transmission. It is a collinear diagram which shows the relationship of the rotation speed (rotation speed) of a sun gear, a carrier and a ring gear of a planetary gear mechanism included in a power split type continuously variable transmission. It is a figure which shows each relationship between an engine water temperature, a creep torque, an idle speed, and a pulley ratio at a time of stopping.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Main part composition of the vehicle>

FIG. 1 is a diagram showing a configuration of a main part of a vehicle 1 on which a transmission ECU 12 according to an embodiment of the present invention is mounted.

The vehicle 1 is an automobile whose drive source is the engine 2.

The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) for injecting fuel into the intake air, and a spark plug for generating electric discharge in the combustion chamber. Has been done. Further, the engine 2 is provided with a starter for starting the engine 2.

The output of the engine 2 is transmitted to the drive wheels (for example, the left and right front wheels) of the vehicle 1 via the torque converter 3 and the continuously variable transmission (CVT) 4.

The vehicle 1 is provided with a plurality of ECUs (Electronic Control Units) having a configuration including a CPU and a memory. The plurality of ECUs include an engine ECU 11 and a transmission ECU 12. Each ECU is connected so that bidirectional communication can be performed by a CAN (Controller Area Network) communication protocol.

An accelerator sensor 13, an engine speed sensor 14, a water temperature sensor 15, and the like are connected to the engine ECU 11.

The accelerator sensor 13 outputs a detection signal according to the amount of operation of the accelerator pedal (not shown) operated by the driver. Based on the signal input from the accelerator sensor 13, the engine ECU 11 sets the ratio of the operation amount to the maximum operation amount of the accelerator pedal, that is, 0% when the accelerator pedal is not depressed, and the accelerator pedal is depressed to the maximum. Calculate the accelerator opening, which is a percentage with time as 100%.

The engine speed sensor 14 outputs a pulse signal synchronized with the rotation of the engine 2 (rotation of the crankshaft) as a detection signal. The engine ECU 11 converts the frequency of the pulse signal input from the engine rotation speed sensor 14 into the rotation speed (engine rotation speed) of the engine 2.

The water temperature sensor 15 outputs a detection signal according to the temperature of the cooling water flowing through the engine 2 (engine water temperature).

The engine ECU 11 is provided in the engine 2 for starting, stopping, and adjusting the output of the engine 2 based on the information acquired from the detection signals of various sensors and / or various information input from other ECUs. Controls electronic throttle valves, injectors and spark plugs.

A shift position sensor 16 or the like is connected to the transmission ECU 12.

The shift position sensor 16 outputs a detection signal according to the position of the shift lever (select lever). As the position of the shift lever, for example, a P position, an R position, an N position and a D position are provided. The P position, R position, N position and D position correspond to the P range (parking range), R range (reverse range), N range (neutral range) and D range (forward range) of the shift range, respectively. The shift lever can perform a shift operation between the P position, the R position, the N position and the D position, and the shift operation can instruct the switching of the shift range.

The transmission ECU 12 has, for example, the gear ratio (unit gear ratio) of the power split type continuously variable transmission 4 based on the information acquired from the detection signals of various sensors and / or various information input from other ECUs. For the change, various valves provided in the hydraulic circuit 17 for supplying the electric pressure to each part of the power split type continuously variable transmission 4 are controlled. The valve includes a hydraulic control valve for controlling the hydraulic pressure supplied to the primary pulley 53 (see FIG. 2) and a hydraulic control valve for controlling the hydraulic pressure supplied to the secondary pulley 54 (see FIG. 2). .. As the oil pressure control valve, a valve capable of controlling the output oil pressure by a current value, for example, a linear solenoid valve is used. Further, the hydraulic circuit 17 is provided with a mechanical oil pump driven by the power of the engine 2 as a source of oil pressure.

<Vehicle drive system>

FIG. 2 is a skeleton diagram showing the configuration of the drive system of the vehicle 1.

The engine 2 includes an E / G output shaft 21. The E / G output shaft 21 is rotated by the power generated by the engine 2.

The torque converter 3 includes a pump impeller 31, a turbine runner 32, and a lockup clutch 33. An E / G output shaft 21 is connected to the pump impeller 31, and the pump impeller 31 is provided so as to be integrally rotatable around the same rotation axis as the E / G output shaft 21. The turbine runner 32 is rotatably provided about the same rotation axis as the pump impeller 31. The lockup clutch 33 is provided to directly connect / separate the pump impeller 31 and the turbine runner 32. When the lockup clutch 33 is engaged, the pump impeller 31 and the turbine runner 32 are directly connected, and when the lockup clutch 33 is released, the pump impeller 31 and the turbine runner 32 are separated.

When the E / G output shaft 21 is rotated while the lockup clutch 33 is released, the pump impeller 31 rotates. When the pump impeller 31 rotates, an oil flow from the pump impeller 31 to the turbine runner 32 is generated. This flow of oil is received by the turbine runner 32, and the turbine runner 32 rotates. At this time, the amplification action of the torque converter 3 occurs, and the turbine runner 32 generates a power larger than the power (torque) of the E / G output shaft 21.

In the state where the lockup clutch 33 is engaged, when the E / G output shaft 21 is rotated, the E / G output shaft 21, the pump impeller 31 and the turbine runner 32 are rotated together.

The power split type continuously variable transmission 4 transmits the power input from the torque converter 3 to the differential gear 6. The power split type continuously variable transmission 4 includes an input shaft 41, an output shaft 42, a continuously variable transmission mechanism 43, a reverse gear mechanism 44, a planetary gear mechanism 45, a split drive gear 46, and a split driven gear 47.

The input shaft 41 is connected to the turbine runner 32 of the torque converter 3 and is provided so as to be integrally rotatable around the same rotation axis as the turbine runner 32.

The output shaft 42 is provided parallel to the input shaft 41. An output gear 48 is supported on the output shaft 42 so as not to rotate relative to each other. The output gear 48 meshes with the differential gear 6 (the input gear of the differential gear 6).

The continuously variable transmission mechanism 43 has the same configuration as a known belt-type continuously variable transmission (CVT). Specifically, the continuously variable transmission mechanism 43 includes a primary shaft 51, a secondary shaft 52 provided in parallel with the primary shaft 51, a primary pulley 53 supported by the primary shaft 51 so as not to rotate relative to the primary shaft 51, and a secondary shaft 52. It is provided with a secondary pulley 54 that is supported so as not to rotate relative to each other, and a belt 55 that is wound around the primary pulley 53 and the secondary pulley 54.

The primary pulley 53 is a movable sheave that is arranged so as to face the fixed sheave 61 fixed to the primary shaft 51 and the fixed sheave 61 with the belt 55 interposed therebetween, and is supported by the primary shaft 51 so as to be movable in the axial direction and not to rotate relative to each other. (Primary sheave) 62 and. A cylinder 63 fixed to the primary shaft 51 is provided on the opposite side of the movable sheave 62 from the fixed sheave 61, and a piston chamber (oil chamber) 64 is formed between the movable sheave 62 and the cylinder 63. There is.

The secondary pulley 54 is arranged so as to face the fixed sheave 65 fixed to the secondary shaft 52 and the fixed sheave 65 with the belt 55 interposed therebetween, and is supported by the secondary shaft 52 so as to be movable in the axial direction and non-relatively rotatable. (Secondary sheave) 66 is provided. A cylinder 67 fixed to the secondary shaft 52 is provided on the opposite side of the movable sheave 66 from the fixed sheave 65, and a piston chamber (oil chamber) 68 is formed between the movable sheave 66 and the cylinder 67. There is. In the direction of the rotation axis, the positional relationship between the fixed sheave 65 and the movable sheave 66 is reversed from the positional relationship between the fixed sheave 61 and the movable sheave 62 of the primary pulley 53.

In the continuously variable transmission mechanism 43, the hydraulic pressure supplied to the piston chambers 64 and 68 of the primary pulley 53 and the secondary pulley 54 is controlled, and the groove widths of the primary pulley 53 and the secondary pulley 54 are changed to change the primary. The pulley ratio between the pulley 53 and the secondary pulley 54 is continuously and steplessly changed.

Specifically, when the pulley ratio is reduced, the oil supply supplied to the piston chamber 64 of the primary pulley 53 is increased. As a result, the movable sheave 62 of the primary pulley 53 moves toward the fixed sheave 61, and the distance (groove width) between the fixed sheave 61 and the movable sheave 62 becomes smaller. Along with this, the winding diameter of the belt 55 with respect to the primary pulley 53 becomes large, and the distance (groove width) between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 becomes large. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 becomes small.

When the pulley ratio is increased, the oil supply to the piston chamber 64 of the primary pulley 53 is reduced. As a result, the thrust of the secondary pulley 54 with respect to the belt 55 becomes larger than the thrust of the primary pulley 53 with respect to the belt 55, the distance between the fixed sheave 65 and the movable sheave 66 of the secondary pulley 54 becomes smaller, and the fixed sheave 61 and the movable sheave 61 become smaller. The distance from 62 becomes large. As a result, the pulley ratio between the primary pulley 53 and the secondary pulley 54 becomes large.

On the other hand, the thrust of the primary pulley 53 and the secondary pulley 54 needs to have a magnitude that does not cause slippage between the primary pulley 53 and the secondary pulley 54 and the belt 55. Therefore, the oil pressure supplied to the piston chamber 68 of the secondary pulley 54 is controlled so that a thrust corresponding to the magnitude of the torque input to the input shaft 41 can be obtained.

The reverse gear mechanism 44 has a configuration in which the power input to the input shaft 41 is reversed and decelerated and transmitted to the primary shaft 51. Specifically, the reverse gear mechanism 44 has a larger diameter and a larger number of teeth than the input shaft gear 71, which is supported by the input shaft 41 so as not to rotate relative to the input shaft 41, and has a larger number of teeth, and is spline-fitted to the primary shaft 51. It includes a primary shaft gear 72 that is supported in the direction of the rotation axis and is non-relatively rotatable and meshes with the input shaft gear 71.

The planetary gear mechanism 45 includes a sun gear 81, a carrier 82, and a ring gear 83. The sun gear 81 is supported on the secondary shaft 52 by spline fitting so that it can move in the direction of the rotation axis and cannot rotate relative to each other. The carrier 82 is fitted onto the output shaft 42 so as to be relatively rotatable. The carrier 82 rotatably supports a plurality of pinion gears 84. A plurality of pinion gears 84 are arranged on the circumference and mesh with the sun gear 81. The ring gear 83 has an annular shape that collectively surrounds a plurality of pinion gears 84, and meshes with each pinion gear 84 from the outside in the rotational radial direction of the secondary shaft 52. Further, an output shaft 42 is connected to the ring gear 83, and the ring gear 83 is provided so as to be integrally rotatable around the same rotation axis as the output shaft 42.

The split drive gear 46 is fitted onto the input shaft 41 so as to be relatively rotatable.

The split driven gear 47 is provided so as to be integrally rotatable around the same rotation axis as the carrier 82 of the planetary gear mechanism 45. The split driven gear 47 is formed to have a smaller diameter than the split drive gear 46 and has a smaller number of teeth than the split drive gear 46.

Further, the power split type continuously variable transmission 4 includes clutches C1 and C2 and a brake B1.

The clutch C1 is switched between an engaged state in which the input shaft 41 and the split drive gear 46 are directly connected (coupled so as to be integrally rotatable) and an released state in which the direct connection is released.

The clutch C2 is switched between an engaged state in which the sun gear 81 of the planetary gear mechanism 45 and the ring gear 83 are directly connected (coupled so as to be integrally rotatable) and an released state in which the direct connection is released.

The brake B1 is switched between an engaged state in which the carrier 82 of the planetary gear mechanism 45 is braked and an released state in which the carrier 82 is allowed to rotate.

<Shift mode>

FIG. 3 is a diagram showing the states of the clutches C1 and C2 and the brake B1 when the vehicle 1 is moving forward and backward. In FIG. 3, “◯” indicates that the clutches C1 and C2 and the brake B1 are in the engaged state. “X” indicates that the clutches C1 and C2 and the brake B1 are in the released state. FIG. 4 is a collinear diagram showing the relationship between the rotation speeds (rotational speeds) of the sun gear 81, the carrier 82, and the ring gear 83 of the planetary gear mechanism 45.

The power split type continuously variable transmission 4 has a belt mode and a split mode as shift modes in the D range.

In the belt mode, as shown in FIG. 3, the clutch C1 and the brake B1 are released and the clutch C2 is engaged. As a result, the split drive gear 46 is separated from the input shaft 41, the carrier 82 of the planetary gear mechanism 45 becomes free (free rotation state), and the sun gear 81 of the planetary gear mechanism 45 and the ring gear 83 are directly connected.

The power input to the input shaft 41 is reversed and decelerated by the reverse gear mechanism 44 and transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43 to rotate the primary shaft 51 and the primary pulley 53. The rotation of the primary pulley 53 is transmitted to the secondary pulley 54 via the belt 55 to rotate the secondary pulley 54 and the secondary shaft 52. Since the sun gear 81 of the planetary gear mechanism 45 and the ring gear 83 are directly connected, the sun gear 81, the ring gear 83, and the output shaft 42 rotate together with the secondary shaft 52. Therefore, in the belt mode, as shown in FIG. 4, the gear ratio (unit gear ratio) of the power split type continuously variable transmission 4 matches the pulley ratio.

In the split mode, the clutch C1 is engaged and the clutch C2 and the brake B1 are released, as shown in FIG. As a result, the input shaft 41 and the split drive gear 46 are directly connected, the carrier 82 of the planetary gear mechanism 45 becomes free, and the sun gear 81 and the ring gear 83 of the planetary gear mechanism 45 are separated.

The power input to the input shaft 41 is reversed and decelerated by the reverse gear mechanism 44, transmitted to the primary shaft 51 of the continuously variable transmission mechanism 43, and transmitted from the primary shaft 51 via the primary pulley 53, the belt 55, and the secondary pulley 54. Is transmitted to the secondary shaft 52, and is transmitted to the sun gear 81 of the planetary gear mechanism 45. On the other hand, the power input to the input shaft 41 is accelerated and transmitted from the split drive gear 46 to the carrier 82 of the planetary gear mechanism 45 via the split driven gear 47.

Since the gear ratio between the split drive gear 46 and the split driven gear 47 is constant and invariant (fixed), in the split mode, if the power input to the input shaft 41 is constant, the carrier 82 of the planetary gear mechanism 45 rotates. Is held at a constant speed. Therefore, when the pulley ratio is increased, the rotation speed of the sun gear 81 of the planetary gear mechanism 45 decreases, so that the rotation speed of the ring gear 83 (output shaft 42) of the planetary gear mechanism 45 decreases as shown by the broken line in FIG. Go up. As a result, in the split mode, the larger the pulley ratio, the smaller the gear ratio of the continuously variable transmission mechanism 43.

The rotation of the output shaft 42 in the belt mode and the split mode is transmitted to the differential gear 6 via the output gear 48. As a result, the drive shafts 7 and 8 of the vehicle 1 rotate in the forward direction.

In R range, becomes reverse mode, as shown in FIG. 3, the clutch C1, C2 is released, the brake B1 is engaged. As a result, the split drive gear 46 is separated from the input shaft 41, the sun gear 81 of the planetary gear mechanism 45 and the ring gear 83 are separated, and the carrier 82 of the planetary gear mechanism 45 is braked.

The power input to the input shaft 41 is reversed and decelerated by the reverse gear mechanism 44, transmitted to the primary shaft 51 of the stepless speed change mechanism 43, and transmitted from the primary shaft 51 via the primary pulley 53, the belt 55, and the secondary pulley 54. The sun gear 81 of the planetary gear mechanism 45 is rotated integrally with the secondary shaft 52. Since the carrier 82 of the planetary gear mechanism 45 is braked, when the sun gear 81 rotates, the ring gear 83 of the planetary gear mechanism 45 rotates in the opposite direction to the sun gear 81. The rotation direction of the ring gear 83 is opposite to the rotation direction of the ring gear 83 during forward movement (belt mode and split mode). Then, the output shaft 42 rotates integrally with the ring gear 83. The rotation of the output shaft 42 is transmitted to the differential gear 6 via the output gear 48. As a result, the drive shafts 7 and 8 of the vehicle 1 rotate in the reverse direction.

<Pulley ratio limiting process>

FIG. 5 shows the relationship between the temperature of the cooling water flowing through the engine 2 (engine water temperature), the driving force output from the output shaft 42 (creep torque), the idle rotation speed of the engine 2, and the pulley ratio when the vehicle is stopped. It is a figure which shows.

For the purpose of improving the starting performance of the vehicle 1, the continuously variable transmission mechanism 43 is usually set before the vehicle 1 is stopped so that the gear ratio of the power split type continuously variable transmission 4 is the maximum gear ratio while the vehicle 1 is stopped. Pulley ratio is changed to the maximum pulley ratio (low return). In order to change the pulley ratio of the continuously variable transmission mechanism 43 to the maximum pulley ratio, the transmission ECU 12 sets the target pulley ratio, which is the target value of the pulley ratio of the continuously variable transmission mechanism 43, to the maximum pulley ratio of the continuously variable transmission mechanism 43. The oil pressure supplied to the primary pulley 53 and the secondary pulley 54 is controlled so that the pulley ratio matches the target pulley ratio. Further, even when the engine 2 is started, the transmission ECU 12 normally sets a target value of the pulley ratio of the continuously variable transmission mechanism 43 so that the gear ratio of the power split type continuously variable transmission 4 becomes the maximum gear ratio. The pulley ratio is set to the maximum pulley ratio of the continuously variable transmission mechanism 43, and the pulley ratio of the continuously variable transmission mechanism 43 is changed to the maximum pulley ratio (low return).

However, as shown in FIG. 5, when the engine water temperature, which is the temperature of the cooling water flowing through the engine 2, is lower than the predetermined temperature T (for example, 80 ° C.), the engine ECU 11 causes the water temperature sensor 15 (see FIG. 1). The engine 2 is controlled so that the lower the engine water temperature acquired from the detection signal of), the higher the idle speed of the engine 2. The idle speed of the engine 2 is higher than the predetermined speed (for example, the engine speed when the device that is the load of the engine 2 such as the air conditioner is not operating and the engine 2 is sufficiently warmed up). In the rotating state, as shown by the two-point chain line in FIG. 5, the driving force (creep torque) during idle rotation of the engine 2 becomes large.

Therefore, the engine water temperature is acquired from the engine ECU 11 by the transmission ECU 12, and the idle speed is high in a state where the engine water temperature is lower than the predetermined temperature T, that is, in the idle high speed state where the idle speed is higher than the predetermined speed. Therefore, the upper limit of the target pulley ratio is limited to a pulley ratio smaller than the maximum pulley ratio of the continuously variable transmission mechanism 43. Specifically, the relationship between the engine water temperature in the idle high rotation state and the upper limit of the target pulley ratio, that is, the relationship between the engine water temperature shown in FIG. 5 and the pulley ratio while the vehicle is stopped is in the form of a two-dimensional map of the transmission ECU 12. It is stored in a non-volatile memory (ROM, flash memory, EEPROM, etc.). Then, based on the two-dimensional map, the transmission ECU 12 sets the target pulley ratio to the pulley ratio according to the engine water temperature acquired from the engine ECU 11. As a result, regardless of the D range and the R range, the creep torque is reduced to the same creep torque as when the idle speed is a predetermined speed in the idle high speed state.

<Effect>

As described above, in the idle high rotation state, when the pulley ratio of the continuously variable transmission mechanism 43 is changed to the target pulley ratio, the upper limit of the target pulley ratio is smaller than the maximum pulley ratio and the engine water temperature (idle rotation). The pulley ratio is limited according to the number). As a result, the creep torque at the time of starting the vehicle 1 can be suppressed. In particular, it is possible to prevent the creep torque from becoming excessive when the vehicle 1 starts in the reverse direction, and to eliminate concerns such as popping out due to creep when the vehicle 1 is released from the brake and generation of a grown sound due to insufficient braking force. Can be done.

<Modification example>

Although one embodiment of the present invention has been described above, the present invention can also be implemented in other embodiments.

For example, the idle speed of the engine 2 is not limited to the case where the engine water temperature is lower than the predetermined temperature T, but also changes depending on whether the air conditioner of the vehicle 1 is turned on or off. Therefore, when the air conditioner is turned on, the upper limit of the target pulley ratio may be limited to a pulley ratio smaller than the maximum pulley ratio of the continuously variable transmission mechanism 43. Further, not limited to the air conditioner, if the electric load (for example, a headlight) whose idle speed of the engine 2 increases when the engine 2 is turned on, the upper limit of the target pulley ratio is set when the electric load is turned on. It may be limited to a pulley ratio smaller than the maximum pulley ratio of the continuously variable transmission mechanism 43.

Further, when the transmission ECU 12 acquires the idle rotation speed of the engine 2 from the engine ECU 11 and the rotation speed of the engine 2 is the idle rotation speed, the creep torque is calculated from the rotation speed to obtain the creep torque. The upper limit of the target pulley ratio may be limited to a pulley ratio smaller than the maximum pulley ratio of the continuously variable transmission mechanism 43 so that the torque is reduced to a constant torque.

Control may be executed to limit the upper limit of the target pulley ratio to a pulley ratio smaller than the maximum pulley ratio of the continuously variable transmission mechanism 43 not only at the time of low return but also during the running of the vehicle 1, or the vehicle 1 may start. From time to low return, control that limits the upper limit of the target pulley ratio to a pulley ratio smaller than the maximum pulley ratio of the continuously variable transmission mechanism 43 may not be executed.

Further, when the vehicle 1 starts on a slope, the control that limits the upper limit of the target pulley ratio to a pulley ratio smaller than the maximum pulley ratio of the continuously variable transmission mechanism 43 may not be executed.

Each of the above-mentioned sensors merely illustrates a sensor related to the present invention, and other sensors may be connected to the engine ECU 11 and the transmission ECU 12.

Some or all of the functions of the engine ECU 11 and the transmission ECU 12 may be integrated into one ECU.

Further, in the above-described embodiment, it is assumed that the hydraulic circuit 17 is provided with a mechanical oil pump, but in addition to the mechanical oil pump, an electric oil pump driven by the power of an electric motor is provided in the hydraulic circuit 17. It may have been. The present invention can also be applied to the control of a vehicle using an electric oil pump.

Although the power split type continuously variable transmission 4 has been taken up as an example of the continuously variable transmission, the present invention can be widely applied to a vehicle equipped with a belt type continuously variable transmission.

In addition, various design changes can be made to the above-mentioned configuration within the scope of the matters described in the claims.

1 Vehicle 2 Engine 4 Power split type continuously variable transmission (continuously variable transmission)
12 Transmission ECU (vehicle control device, pulley ratio changing means, pulley ratio limiting means)
41 Input shaft 42 Output shaft 43 Continuously variable transmission mechanism 45 Planetary gear mechanism 53 Primary pulley 54 Secondary pulley 55 Belt 81 Sun gear 82 Carrier 83 Ring gear

Claims (1)

A belt-type continuously variable transmission that shifts power steplessly by changing the pulley ratio of the primary pulley and secondary pulley on the power transmission path from the input shaft where the engine power is input to the output shaft where the power is output. And a planetary gear mechanism including a carrier, a sun gear provided so as to be integrally rotatable with the secondary pulley, and a ring gear provided so as to be integrally rotatable with the output shaft, and the carrier is in a free rotation state in the forward range. The control used in a vehicle equipped with a continuously variable transmission in which the sun gear and the ring gear are directly connected, the direct connection between the sun gear and the ring gear is released in the reverse range, and the carrier is fixed so as not to rotate. It ’s a device,
A pulley ratio changing means for changing the pulley ratio of the continuously variable transmission mechanism to a target pulley ratio, and
In the idle high rotation state where the idle speed of the engine is higher than the predetermined rotation speed, the upper limit of the target pulley ratio is set to a pulley ratio smaller than the maximum pulley ratio of the stepless speed change mechanism according to the idle high rotation state. Including pulley ratio limiting means to limit
The pulley ratio limiting means during traveling of the vehicle, depending on the water temperature of the engine, the rather smaller than the upper limit of the target pulley ratio maximum pulley ratio of the continuously variable transmission mechanism, and as the water temperature of the engine is low limited to have small pulley ratio, the vehicle control device.

Images