JP2023163966A - Control device of vehicle - Google Patents

Abstract

To suppress deterioration of drivability caused by difficulty in obtaining a torque amplification action of a torque converter at a start of a vehicle involved in turning on of an accelerator.SOLUTION: When a traveling state of a vehicle has entered a prescribed traveling state where a torque amplification action of a torque converter is difficult to obtain due to increase in an output rotational speed of the torque converter after a start of the vehicle involved in turning on of an accelerator, a required torque value for an engine is increased from a value corresponding to an amount of acceleration operation by a driver until the traveling state enters a second prescribed traveling state where acceleration feeling is less likely to deteriorate. So, a drop of vehicle acceleration due to torque converter characteristics involved in an increase in vehicle speed can be suppressed. Thus, at the start of the vehicle involved in turning on of the accelerator, deterioration of drivability caused by difficulty in obtaining a torque amplification action of the torque converter can be suppressed.SELECTED DRAWING: Figure 3

Description

The present invention relates to a control device for a vehicle that includes an engine and a torque converter.

2. Description of the Related Art A control device for a vehicle is well known, which includes an engine and a power transmission device having a torque converter connected to the engine and provided in a power transmission path between the engine and drive wheels. For example, the vehicle control device described in Patent Document 1 is one such example. This Patent Document 1 states that the output of the engine is input to a torque converter, and from this torque converter is input to a continuously variable transmission, and that the output of the continuously variable transmission is transmitted to a differential gear etc. It is disclosed that the energy is distributed to the drive wheels of the vehicle.

Japanese Patent Application Publication No. 2021-188639

By the way, when the vehicle starts with the start of acceleration operation by the driver, that is, when the accelerator is turned on, the output rotational speed of the torque converter increases as the vehicle speed increases, and the differential rotational speed of the torque converter (=input rotational speed - When the output rotation speed) decreases, that is, when the speed ratio of the torque converter (= output rotation speed / input rotation speed) increases, the torque ratio of the torque converter (= output torque / input torque) decreases, that is, when the torque converter's speed ratio (= output rotation speed / input rotation speed) decreases. It becomes difficult to obtain a torque amplification effect, and the vehicle acceleration decreases. In particular, in vehicles where the gear ratio in the power transmission device downstream of the torque converter is larger than that used when starting, the differential rotation speed of the torque converter decreases because the amount of increase in the output rotation speed of the torque converter increases as the vehicle speed increases. This may make it even more difficult to obtain the torque amplification effect of the torque converter. Therefore, there is a possibility that the vehicle acceleration decreases significantly as the vehicle speed increases, resulting in deterioration of drivability.

The present invention has been made against the background of the above-mentioned circumstances, and its purpose is to improve drivability due to the difficulty in obtaining the torque amplification effect of the torque converter when the vehicle starts with the accelerator being turned on. An object of the present invention is to provide a vehicle control device that can suppress deterioration.

The gist of the first invention is as follows: (a) a power transmission device having an engine and a torque converter connected to the engine and provided in a power transmission path between the engine and drive wheels; (b) After the vehicle starts in response to the start of an acceleration operation by a driver, the running state of the vehicle changes such that the torque increases as the output rotational speed of the torque converter increases. When a predetermined driving condition occurs in which it is difficult to obtain a torque amplification effect in the converter, the required value of the torque of the engine is changed to The purpose is to increase the value according to the amount of acceleration operation by the operator.

According to the first invention, after the vehicle starts when the accelerator is turned on, the running state of the vehicle becomes a predetermined running state in which it becomes difficult to obtain a torque amplification effect in the torque converter as the output rotational speed of the torque converter increases. In this case, the required value of engine torque is increased from the value corresponding to the amount of acceleration operation by the driver until a second predetermined driving state is reached in which the feeling of acceleration is less likely to deteriorate, so that the vehicle speed is increased. It is possible to suppress a drop in vehicle acceleration due to the torque converter characteristics as the torque increases. Therefore, it is possible to suppress deterioration of drivability due to difficulty in obtaining the torque amplification effect of the torque converter when the vehicle starts with the accelerator being turned on.

1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and a diagram illustrating main parts of a control function and a control system for various controls in the vehicle. It is a figure which shows an example of the predetermined relationship between speed ratio and torque ratio among torque converter characteristics. This is a flowchart illustrating the main part of the control operation of the electronic control device, and shows the control operation for suppressing deterioration of drivability due to the difficulty in obtaining the torque amplification effect of the torque converter when the vehicle starts due to the accelerator being turned on. It is a flowchart explaining. 4 is a diagram showing an example of a time chart when the control operation shown in the flowchart of FIG. 3 is executed. FIG. This is a flowchart illustrating the main part of the control operation of the electronic control device, and shows the control operation for suppressing deterioration of drivability due to the difficulty in obtaining the torque amplification effect of the torque converter when the vehicle starts due to the accelerator being turned on. This is a flowchart to be explained, and is a different embodiment from FIG. 3.

In an embodiment of the present invention, the power transmission device includes, for example, an automatic transmission in a power transmission path between the torque converter and the drive wheels. The automatic transmission is, for example, a known planetary gear type automatic transmission, a known continuously variable transmission, or a plurality of power transmission paths including a first power transmission path via a gear mechanism and a second power transmission path through a continuously variable transmission. This is an automatic transmission such as a known transmission in which two power transmission paths are provided in parallel.

The continuously variable transmission is, for example, a continuously variable transmission in which a transmission element is wound around a primary pulley and a secondary pulley. The primary pulley, which is an input-side pulley, and the secondary pulley, which is an output-side pulley, each have a thrust force for changing the fixed sheave, the movable sheave, and the groove width between the fixed sheave and the movable sheave. and a hydraulic actuator for applying the pressure. The vehicle includes a hydraulic control circuit that independently controls pulley hydraulic pressures as working hydraulic pressures supplied to the hydraulic actuators. This hydraulic control circuit may be configured to, for example, control the flow rate of hydraulic fluid to the hydraulic actuator, resulting in a pulley hydraulic pressure. Such a hydraulic control circuit controls each thrust force (=pulley oil pressure x pressure receiving area) at the primary pulley and the secondary pulley, thereby realizing the target speed change while preventing the transmission element from slipping. Shift control is executed as follows. The transmission element is an endless annular compression type transmission belt having an endless annular hoop and a large number of thick plate-like blocks arranged in the thickness direction along the hoop, or an endless annular compression transmission belt, or This is a tension type power transmission belt, etc., which constitutes an endless ring-shaped link chain in which the ends of overlapping link plates are interconnected by connecting pins. The continuously variable transmission is a known belt type continuously variable transmission. In a broad sense, the concept of a belt-type continuously variable transmission includes a chain-type continuously variable transmission.

Further, the speed ratio (also referred to as gear ratio) in the power transmission device, the continuously variable transmission, etc. is "rotational speed of the rotating member on the input side/rotating speed of the rotating member on the output side." For example, the gear ratio of the continuously variable transmission is "rotational speed of primary pulley/rotational speed of secondary pulley." The high side in the gear ratio is the high vehicle speed side where the gear ratio becomes smaller. The low side in the gear ratio is the low vehicle speed side where the gear ratio increases. For example, the lowest side gear ratio is a gear ratio on the lowest vehicle speed side where the vehicle speed is lowest, and is a maximum gear ratio where the gear ratio has the largest value.

Further, the engine is a known internal combustion engine such as a gasoline engine or a diesel engine that generates power by burning fuel, for example. Furthermore, the vehicle may include a rotating machine or the like in addition to the engine.

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

FIG. 1 is a diagram illustrating a schematic configuration of a vehicle 10 to which the present invention is applied, as well as a diagram illustrating main parts of a control function and a control system for various controls in the vehicle 10. In FIG. 1, a vehicle 10 includes an engine 12 functioning as a power source, drive wheels 14, and a power transmission device 16 provided in a power transmission path between the engine 12 and the drive wheels 14.

The engine 12 is a known internal combustion engine such as a gasoline engine or a diesel engine. The engine 12 has an engine torque Te, which is the torque of the engine 12, by controlling an engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, etc. provided in the vehicle 10 by an electronic control device 90, which will be described later. controlled.

The power transmission device 16 includes a torque converter 20, an input shaft 22, a continuously variable transmission mechanism 24, a forward/reverse switching device 26, a gear mechanism 28, an output shaft 30, and a counter shaft in a case 18, which is a non-rotating member attached to the vehicle body. 32, a reduction gear device 34, a gear 36, a differential gear 38, and the like. The power transmission device 16 also includes left and right axles 40 connected to a differential gear 38 . The torque converter 20 has an input side connected to the engine 12. The input shaft 22 is integrally connected to a turbine shaft that is an output rotating member of the torque converter 20, and is a rotating member that connects the output side of the torque converter 20 and the input side of the continuously variable transmission mechanism 24. It is a rotating member that connects the output side of the torque converter 20 and the input side of the forward/reverse switching device 26. The continuously variable transmission mechanism 24 has an input side connected to the input shaft 22, and an output side connected to an output shaft 30 via a second clutch C2, which will be described later. The gear mechanism 28 has an input side connected to the input shaft 22 via the forward/reverse switching device 26, and an output side connected to the output shaft 30. The input shaft 22 is an input rotating member to which the power of the engine 12 is transmitted, and is a common input rotating member for the continuously variable transmission mechanism 24 and the gear mechanism 28. The output shaft 30 is an output rotating member that outputs the power of the engine 12 to the drive wheels 14, and is a common output rotating member of the continuously variable transmission mechanism 24 and the gear mechanism 28. The continuously variable transmission mechanism 24 and the gear mechanism 28 are provided in parallel in the power transmission path between the input shaft 22 and the output shaft 30. The continuously variable transmission mechanism 24 and the gear mechanism 28 are automatic transmissions provided in a power transmission path between the torque converter 20 and the drive wheels 14. The reduction gear device 34 is a reduction mechanism consisting of a pair of gears that are provided on the output shaft 30 and the counter shaft 32 so that they cannot rotate relative to each other, and mesh with each other. The gear 36 is provided on the counter shaft 32 so as not to be relatively rotatable, and is connected to the input side of the differential gear 38. The above-mentioned power also includes driving force, torque, and force unless otherwise specified.

In the power transmission device 16 configured in this manner, the power output from the engine 12 is sequentially transmitted through the torque converter 20, the forward/reverse switching device 26, the gear mechanism 28, the reduction gear device 34, the differential gear 38, the axle 40, etc. , are transmitted to the left and right drive wheels 14. Alternatively, in the power transmission device 16, the power output from the engine 12 is transmitted to the left and right drive wheels 14 via the torque converter 20, the continuously variable transmission mechanism 24, the reduction gear device 34, the differential gear 38, the axle 40, etc. be done.

The torque converter 20 includes a pump wheel 20p connected to the engine 12 and a turbine wheel 20t connected to the input shaft 22. Torque converter 20 is a fluid transmission device that transmits power from engine 12 to input shaft 22 via fluid. The torque converter 20 includes a lock-up clutch 20lu as a known direct clutch that connects the pump wheel 20p and the turbine wheel 20t, that is, connects the input and output rotating members of the torque converter 20.

The lock-up clutch 20lu is a hydraulic friction engagement device configured by, for example, a multi-plate or single-plate clutch. The lock-up clutch 20lu is configured such that the LU torque Tlu, which is the torque capacity of the lock-up clutch 20lu, is changed by the LU oil pressure PRlu, which is a regulated oil pressure supplied from the hydraulic control circuit 52 provided in the vehicle 10. The operating state or control state is switched. The control states of the lock-up clutch 20lu include a released state (also referred to as a fully released state) in which the lock-up clutch 20lu is released, a slip state in which the lock-up clutch 20lu is engaged with slippage, and a slip state in which the lock-up clutch 20lu is engaged with slippage. and an engaged state (also referred to as a fully engaged state) in which the lock-up clutch 20lu is engaged.

The power transmission device 16 includes a plurality of power transmission paths that are provided in parallel between the input shaft 22 and the output shaft 30 and can each transmit the power of the engine 12 from the input shaft 22 to the output shaft 30. ing. The plurality of power transmission paths include a first power transmission path PT1 that transmits the power of the engine 12 from the input shaft 22 via the gear mechanism 28 to the output shaft 30 and the driving wheels 14; This is a second power transmission path PT2 that transmits power from the output shaft 30 to the drive wheels 14 via the continuously variable transmission mechanism 24.

In the power transmission device 16, the power transmission path for transmitting the power of the engine 12 to the driving wheels 14 is switched between a first power transmission path PT1 and a second power transmission path PT2 depending on the running state of the vehicle 10. Therefore, the power transmission device 16 includes a plurality of engagement devices that selectively form the first power transmission path PT1 and the second power transmission path PT2. The plurality of engagement devices include a first clutch C1, a first brake B1, and a second clutch C2. The first clutch C1 is provided in the first power transmission path PT1, is an engagement device that selectively connects or disconnects the first power transmission path PT1, and is engaged during forward movement. This is an engagement device that forms the first power transmission path PT1. The first brake B1 is provided on the first power transmission path PT1, and is an engagement device that selectively connects or disconnects the first power transmission path PT1, and is engaged when traveling backward. This is an engagement device that forms the first power transmission path PT1. The first power transmission path PT1 is formed by engagement of the first clutch C1 or the first brake B1. The second clutch C2 is provided in the second power transmission path PT2, and is an engagement device that selectively connects or disconnects the second power transmission path PT2. This is an engagement device that forms two power transmission paths PT2. The second power transmission path PT2 is formed by engagement of the second clutch C2. The first clutch C1, the first brake B1, and the second clutch C2 are all known hydraulic wet friction engagement devices that are frictionally engaged by respective hydraulic actuators. The first clutch C1 is a first frictional engagement device for forward movement, the second clutch C2 is a second frictional engagement device, and the first brake B1 is a first frictional engagement device for reverse movement. The first clutch C1 and the first brake B1 are each one of the elements constituting the forward/reverse switching device 26, as described later. The control state of the first clutch C1, the first brake B1, and the second clutch C2 is changed by changing the torque capacity of the engagement device by the regulated hydraulic pressure supplied from the hydraulic control circuit 52. Can be switched.

The forward/reverse switching device 26 includes a double pinion type planetary gear device 26p, a first clutch C1, and a first brake B1. The planetary gear device 26p is a differential mechanism having three rotating elements: a carrier 26c as an input element, a sun gear 26s as an output element, and a ring gear 26r as a reaction element. Carrier 26c is connected to input shaft 22. Ring gear 26r is selectively connected to case 18 via first brake B1. The sun gear 26s is connected to a small diameter gear 60 that is provided around the input shaft 22 so as to be relatively rotatable coaxially with respect to the input shaft 22. Carrier 26c and sun gear 26s are selectively coupled via first clutch C1.

The gear mechanism 28 includes a small diameter gear 60, a gear mechanism counter shaft 62, and a large diameter gear that is provided around the gear mechanism counter shaft 62 so as to be coaxially non-rotatable relative to the gear mechanism counter shaft 62 and meshes with the small diameter gear 60. A gear 64 is provided. The large diameter gear 64 has a larger diameter than the small diameter gear 60. Further, the gear mechanism 28 includes an idler gear 66 which is provided around the gear mechanism counter shaft 62 so as to be relatively rotatable coaxially with respect to the gear mechanism counter shaft 62, and an idler gear 66 which is provided around the output shaft 30 so as to be relatively rotatable coaxially with respect to the gear mechanism counter shaft 62. The output gear 68 is provided centrally so as to be relatively unrotatable and meshes with the idler gear 66. Output gear 68 has a larger diameter than idler gear 66. Therefore, in the gear mechanism 28, one gear stage is formed in the power transmission path between the input shaft 22 and the output shaft 30. The gear mechanism 28 is a gear mechanism with gear stages, that is, a gear mechanism with fixed gear ratios (gear ratios). The gear mechanism 28 further includes a meshing mechanism that is provided around the gear mechanism counter shaft 62 and between the large diameter gear 64 and the idler gear 66 to selectively connect or disconnect the power transmission path between them. It is equipped with a type clutch D1. The dog clutch D1 is an engagement device that selectively connects or disconnects the first power transmission path PT1, and is engaged together with the first clutch C1 or the first brake B1 to transmit the first power. This is an engagement device that forms the transmission path PT1, and is included in the plurality of engagement devices. The dog clutch D1 is switched between an engaged state and a disengaged state by operating a hydraulic actuator 54 provided in the vehicle 10 using regulated hydraulic pressure supplied from the hydraulic control circuit 52.

The first power transmission path PT1 is formed by engaging both the dog clutch D1 and the first clutch C1 or first brake B1, which is provided closer to the input shaft 22 than the dog clutch D1. . In the first power transmission path PT1, a forward power transmission path is formed by engagement of the first clutch C1 and dog clutch D1, while a reverse power transmission path is formed by engagement of the first brake B1 and dog clutch D1. A power transmission path is formed. In the power transmission device 16, when the first power transmission path PT1 is formed, the power transmission device 16 is placed in a power transmission enabled state in which the power of the engine 12 can be transmitted from the input shaft 22 to the output shaft 30 via the gear mechanism 28. . On the other hand, when both the first clutch C1 and the first brake B1 are released, or when the dog clutch D1 is released, the first power transmission path PT1 is brought into a neutral state in which power transmission is disabled.

The continuously variable transmission mechanism 24 includes a primary shaft 70 provided coaxially with the input shaft 22 and integrally connected to the input shaft 22, a primary pulley 72 with a variable effective diameter connected to the primary shaft 70, and an output shaft. A secondary shaft 74 provided coaxially with the shaft 30, a secondary pulley 76 with a variable effective diameter connected to the secondary shaft 74, and a transmission belt as a transmission element wound between each of the pulleys 72 and 76. It is equipped with 78. The continuously variable transmission mechanism 24 is a known belt-type continuously variable transmission in which power is transmitted through frictional force between each pulley 72 , 76 and a transmission belt 78 , and transmits power from the engine 12 to the driving wheels 14 . Communicate to the side. The frictional force is also referred to as belt clamping force. This belt squeezing force is belt torque capacity, which is the torque capacity of the transmission belt 78 in the continuously variable transmission mechanism 24.

The primary pulley 72 includes a fixed sheave 72a connected to the primary shaft 70, a movable sheave 72b provided so as to be unable to rotate relative to the fixed sheave 72a around the axis of the primary shaft 70 and movable in the axial direction. A hydraulic actuator 72c that applies a primary thrust Wpri to the movable sheave 72b is provided. The primary thrust Wpri is the thrust of the primary pulley 72 (=primary pressure Ppri×pressure receiving area) for changing the V-groove width between the fixed sheave 72a and the movable sheave 72b. In other words, the primary thrust Wpri is the thrust of the primary pulley 72 that pinches the transmission belt 78, which is applied by the hydraulic actuator 72c. The primary pressure Ppri is a hydraulic pressure supplied to the hydraulic actuator 72c by the hydraulic control circuit 52, and is a pulley hydraulic pressure that generates the primary thrust Wpri. Further, the secondary pulley 76 includes a fixed sheave 76a connected to the secondary shaft 74, and a movable sheave 76b provided so as to be unable to rotate relative to the fixed sheave 76a around the axis of the secondary shaft 74 and movable in the axial direction. and a hydraulic actuator 76c that applies a secondary thrust Wsec to the movable sheave 76b. The secondary thrust Wsec is the thrust of the secondary pulley 76 (=secondary pressure Psec×pressure receiving area) for changing the V-groove width between the fixed sheave 76a and the movable sheave 76b. That is, the secondary thrust force Wsec is the thrust force of the secondary pulley 76 that pinches the transmission belt 78, which is applied by the hydraulic actuator 76c. The secondary pressure Psec is the hydraulic pressure supplied to the hydraulic actuator 76c by the hydraulic control circuit 52, and is the pulley hydraulic pressure that generates the secondary thrust force Wsec.

In the continuously variable transmission mechanism 24, a primary pressure Ppri and a secondary pressure Psec are each controlled by a hydraulic control circuit 52 driven by an electronic control device 90, which will be described later, so that a primary thrust Wpri and a secondary thrust Wsec are respectively controlled. Ru. As a result, in the continuously variable transmission mechanism 24, the V-groove width of each pulley 72, 76 changes, the engaging diameter (=effective diameter) of the transmission belt 78 is changed, and the gear ratio γcvt (=primary rotation speed Npri/secondary rotation The belt clamping force is controlled so that the transmission belt 78 does not slip. That is, by controlling the primary thrust Wpri and the secondary thrust Wsec, belt slippage, which is slippage of the transmission belt 78, is prevented, and the gear ratio γcvt of the continuously variable transmission mechanism 24 is set to the target gear ratio γcvttgt. The primary rotational speed Npri is the rotational speed of the primary shaft 70, is the input rotational speed of the continuously variable transmission mechanism 24, and is the same as the rotational speed of the primary pulley 72. The primary rotational speed Npri is the same as the input shaft rotational speed Nin, which is the rotational speed of the input shaft 22, and is also the same as the turbine rotational speed, which is the rotational speed of the turbine shaft of the torque converter 20, that is, the output rotational speed of the torque converter 20. It is. The secondary rotational speed Nsec is the rotational speed of the secondary shaft 74, is the output rotational speed of the continuously variable transmission mechanism 24, and is the same as the rotational speed of the secondary pulley 76.

In the continuously variable transmission mechanism 24, when the primary pressure Ppri is increased, the V-groove width of the primary pulley 72 is narrowed, and the gear ratio γcvt is reduced. Reducing the gear ratio γcvt means that the continuously variable transmission mechanism 24 is upshifted. On the other hand, in the continuously variable transmission mechanism 24, when the primary pressure Ppri is lowered, the V groove width of the primary pulley 72 is widened and the gear ratio γcvt is increased. Increasing the gear ratio γcvt means that the continuously variable transmission mechanism 24 is downshifted. In the continuously variable transmission mechanism 24, the lowest side gear ratio γmax is formed where the V-groove width of the primary pulley 72 is maximized. In the continuously variable transmission mechanism 24, belt slippage is prevented by the primary thrust Wpri and the secondary thrust Wsec, and the target gear ratio γcvttgt is realized by the mutual relationship between the primary thrust Wpri and the secondary thrust Wsec. The target speed change cannot be achieved with only one thrust force. The gear ratio of the continuously variable transmission mechanism 24 is changed by changing the thrust ratio τ (=Wsec/Wpri), which is the value of the ratio between the primary thrust Wpri and the secondary thrust Wsec, due to the interaction between the primary pressure Ppri and the secondary pressure Psec. γcvt is changed. The thrust ratio τ is the value of the ratio of the secondary thrust Wsec to the primary thrust Wpri. For example, as the thrust ratio τ increases, the gear ratio γcvt increases, that is, the continuously variable transmission mechanism 24 is downshifted.

The output shaft 30 is coaxially and relatively rotatably arranged with respect to the secondary shaft 74 . The second clutch C2 is provided in the power transmission path between the secondary pulley 76 and the output shaft 30. The second power transmission path PT2 is formed by engaging the second clutch C2. When the second power transmission path PT2 is formed, the power transmission device 16 enters a power transmission enabled state in which the power of the engine 12 can be transmitted from the input shaft 22 to the output shaft 30 via the continuously variable transmission mechanism 24. be done. On the other hand, the second power transmission path PT2 is brought into a neutral state when the second clutch C2 is released. The gear ratio γcvt of the continuously variable transmission mechanism 24 corresponds to the gear ratio in the second power transmission path PT2.

In the power transmission device 16, the speed ratio EL of the gear mechanism 28, which is the speed ratio γgear (=input shaft rotational speed Nin/output shaft rotational speed Nout) in the first power transmission path PT1, is the maximum speed change in the second power transmission path PT2. The lowermost gear ratio γmax of the continuously variable transmission mechanism 24 is set to a larger value than the lowest gear ratio γmax. That is, the gear ratio EL is set to a gear ratio lower than the lowest gear ratio γmax. The gear ratio EL of the gear mechanism 28 corresponds to the first gear ratio γ1 in the power transmission device 16, and the lowest side gear ratio γmax of the continuously variable transmission mechanism 24 corresponds to the second gear ratio γ2 in the power transmission device 16. Equivalent to. In this way, the second power transmission path PT2 has a higher gear ratio than the first power transmission path PT1. The output shaft rotation speed Nout is the rotation speed of the output shaft 30.

The vehicle 10 can selectively run in a gear drive mode or in a belt drive mode. The gear running mode is a running mode in which the first power transmission path PT1 is formed in the power transmission device 16. The belt running mode is a running mode in which the second power transmission path PT2 is formed in the power transmission device 16. In the gear running mode, when forward running is possible, the first clutch C1 and dog clutch D1 are engaged, and the second clutch C2 and first brake B1 are released. In the gear driving mode, when backward driving is possible, the first brake B1 and dog clutch D1 are engaged, and the second clutch C2 and first clutch C1 are released. In the belt running mode, the second clutch C2 is engaged, and the first clutch C1 and first brake B1 are released. In this belt running mode, forward running is possible.

The gear running mode is selected in a relatively low vehicle speed range, including when the vehicle is stopped. The belt running mode is selected in a relatively high vehicle speed range including a medium vehicle speed range. Of the belt running modes, dog clutch D1 is engaged in a belt running mode in a medium vehicle speed region, while dog clutch D1 is disengaged in a belt running mode in a high vehicle speed region of belt running modes. . The dog clutch D1 is released in the belt running mode in the high vehicle speed range, for example, to eliminate the drag of the gear mechanism 28, etc. during running in the belt running mode, and also to eliminate the drag of the gear mechanism 28 and the planetary gear in the high vehicle speed range. This is to prevent a component of the device 26p, such as a pinion, from rotating at a high speed. When the gear mechanism 28 is prevented from increasing in rotation speed, for example, the differential rotation speed between the input side rotation speed and the output side rotation speed of the first clutch C1 is prevented from increasing, and the friction of the first clutch C1 is prevented. Improves the durability of the material.

The vehicle 10 includes a mechanical oil pump 56. The oil pump 56 is connected to the pump impeller 20p, and is rotationally driven by the engine 12 to discharge hydraulic oil OIL used in the power transmission device 16. The hydraulic oil OIL discharged by the oil pump 56 is supplied to the hydraulic control circuit 52. The oil pressure control circuit 52 includes LU oil pressure PRlu, oil pressure for controlling the speed change of the continuously variable transmission mechanism 24, and belt clamping force in the continuously variable transmission mechanism 24, each of which is regulated based on the hydraulic oil OIL discharged by the oil pump 56. It supplies oil pressure for generating the same, and oil pressure for switching the control states of each of the first clutch C1, first brake B1, second clutch C2, and dog clutch D1.

The vehicle 10 further includes an electronic control device 90 as a controller including a control device for the vehicle 10. The electronic control device 90 includes, for example, a so-called microcomputer equipped with a CPU, RAM, ROM, input/output interface, etc., and the CPU uses the temporary storage function of the RAM and executes programs stored in the ROM in advance. Various controls of the vehicle 10 are executed by performing signal processing. The electronic control device 90 is configured to be divided into one for engine control, one for oil pressure control, etc. as necessary.

The electronic control device 90 includes various sensors installed in the vehicle 10 (for example, an engine rotation speed sensor 80, an input shaft rotation speed sensor 81, a secondary rotation speed sensor 82, an output shaft rotation speed sensor 83, an accelerator opening sensor 84, Various signals based on detected values by throttle valve opening sensor 85, brake switch 86, G sensor 87, operation position sensor 88, etc. The input shaft rotational speed Nin, the secondary rotational speed Nsec, the output shaft rotational speed Nout corresponding to the vehicle speed V, the accelerator opening θacc as the amount of acceleration operation by the driver, that is, the amount of accelerator operation, representing the magnitude of the driver's acceleration operation, The throttle valve opening θth is the opening of the electronic throttle valve, the brake-on signal Bon is a signal indicating that the brake pedal for operating the wheel brake is being operated by the driver, and the vehicle is the longitudinal acceleration of the vehicle 10. The acceleration G, the operation position (=operation position) POSop, etc. indicating the position at which the shift lever 89 provided in the vehicle 10 is operated are supplied.

The electronic control device 90 also sends various command signals (for example, an engine control command signal Se for controlling the engine 12, no A CVT hydraulic control command signal Scvt for controlling the speed change of the step change mechanism 24, belt clamping force, etc., a CVT hydraulic control command signal Scvt for controlling each of the first clutch C1, first brake B1, second clutch C2, and dog clutch D1. A CBD hydraulic control command signal Scbd, an LU hydraulic control command signal Slu for controlling the lock-up clutch 20lu, etc.) are output, respectively.

The shift lever 89 is a shift operation member that is operated by the driver to any one of the plurality of operation positions POSop. The operation position POSop is a signal representing the selected state of the power transmission state in the power transmission device 16, and includes, for example, P, R, N, and D operation positions. The P operation position is a parking operation position that selects the P position of the power transmission device 16 in which the power transmission device 16 is in a neutral state and the output shaft 30 is mechanically fixed so as not to rotate. The neutral state of the power transmission device 16 is realized, for example, by releasing all of the first clutch C1, first brake B1, and second clutch C2. That is, the neutral state of the power transmission device 16 is a state in which neither the first power transmission path PT1 nor the second power transmission path PT2 is formed. The R operation position is a reverse travel operation position that selects the R position of the power transmission device 16 that enables reverse travel in the gear travel mode. The N operation position is a neutral operation position that selects the N position of the power transmission device 16 in which the power transmission device 16 is in the neutral state. The D operation position is the D position of the power transmission device 16 that enables forward travel in gear travel mode or executes automatic speed change control of the continuously variable transmission mechanism 24 in belt travel mode to enable forward travel. This is the forward travel operation position for selecting the position.

The electronic control device 90 includes an engine control means, that is, an engine control section 92, a speed change control means, that is, a speed change control section 94, and a lock-up clutch control means, that is, a lock-up clutch control section 96, in order to realize various controls in the vehicle 10. ing.

The engine control unit 92 calculates the amount of drive required by the driver for the vehicle 10, for example, by applying the accelerator opening θacc and the vehicle speed V to the requested amount of drive map. The required drive amount map is a relationship for determining the required drive amount that has been determined and stored in advance experimentally or by design, that is, is predetermined. The required drive amount is, for example, the required drive force Frdem[N] at the drive wheels 14. As the required drive amount, the required drive torque Trdem [Nm] for the drive wheels 14, the required output shaft torque for the output shaft 30, etc. can also be used.

The engine control unit 92 calculates the required value of the engine torque Te, that is, the required engine torque Tedem, for obtaining the engine torque Te that realizes the required driving force Frdem, using, for example, the following predetermined equation (1). In the following equation (1), "Te" is the engine torque. “F” is the driving force Fr at the driving wheels 14. "rw" is the tire dynamic load radius of the drive wheel 14. “γ” is the actual speed ratio γcvt (=Npri/Nsec) of the continuously variable transmission mechanism 24 calculated by the speed change control unit 94 based on the primary rotation speed Npri and the secondary rotation speed Nsec when in the belt running mode. , when in the gear running mode, the gear ratio EL (=γgear) of the gear mechanism 28 is predetermined. "i" is the reduction ratio of the reduction gear device 34, differential gear 38, etc. "t" is the torque ratio of the torque converter 20 (=turbine torque Tt/pump torque Tp). The turbine torque Tt is the torque output from the torque converter 20, and is the same as the torque input to the continuously variable transmission mechanism 24, that is, the input shaft torque Tin. The pump torque Tp is the torque input to the torque converter 20, and is the same as the engine torque Te. The torque ratio t is a function of the speed ratio e (=turbine rotation speed/pump rotation speed) of the torque converter 20. The engine control unit 92 calculates the torque ratio t by applying the actual speed ratio e to a predetermined relationship between the speed ratio e and the torque ratio t as shown in FIG. 2, for example. The engine control unit 92 is based on an input shaft rotational speed Nin, which is the rotational speed of the turbine impeller 20t, which is the same as the turbine rotational speed, and an engine rotational speed Ne, which is the rotational speed of the pump impeller 20p, which is the same as the pump rotational speed. , calculate the actual speed ratio e (=Nin/Ne). The engine control unit 92 calculates "Te" as the required engine torque Tedem by substituting the required driving force Frdem into "F". The engine control unit 92 calculates the required engine torque Tedem, that is, the driver requested engine torque Tedemd according to the accelerator opening θacc, by a predetermined torque calculation using a predetermined engine torque calculation formula as shown in the following equation (1). .

Te=(F×rw)/(γ×i×t)…(1)

The engine control unit 92 uses a predetermined relationship, for example, an engine torque map, to calculate a target throttle valve opening θthtgt that provides the required engine torque Tedem. The engine control unit 92 sets the actual throttle valve opening θth to the target throttle valve opening θthtgt so that the required engine torque Tedem is obtained, and also sends an engine control command signal Se for controlling the injection signal, ignition timing signal, etc. is output to the engine control device 50.

When the operating position POSop is the P operating position or the N operating position while the vehicle is stopped, the shift control unit 94 controls the CBD oil pressure for engaging the dog clutch D1 in preparation for shifting to the gear drive mode. A control command signal Scbd is output to the hydraulic control circuit 52. When the operating position POSop is changed from the P operating position or the N operating position to the D operating position while the vehicle is stopped, the shift control unit 94 sends a CBD hydraulic control command signal Scbd for engaging the first clutch C1. Output to the hydraulic control circuit 52. As a result, the driving mode is shifted to a gear driving mode that enables forward driving. When the operating position POSop is changed from the P operating position or the N operating position to the R operating position while the vehicle is stopped, the shift control unit 94 sends a CBD hydraulic control command signal Scbd for engaging the first brake B1. Output to the hydraulic control circuit 52. As a result, the driving mode is shifted to a gear driving mode that enables reverse driving.

When the operating position POSop is the D operating position, the shift control unit 94 executes switching control to switch between the gear running mode and the belt running mode. Specifically, the shift control unit 94 corresponds to the first gear ratio corresponding to the gear ratio EL of the gear mechanism 28 in the gear running mode and the lowest gear ratio γmax of the continuously variable transmission mechanism 24 in the belt running mode. The vehicle speed V and the accelerator opening θacc are applied to an upshift line and a downshift line as a stepped transmission map, which has a predetermined relationship and has a predetermined hysteresis for switching between the second gear and the second gear. This determines whether or not a shift is necessary, and changes the driving mode based on the result of that determination.

When the shift control unit 94 determines an upshift while driving in the gear driving mode and switches to the belt driving mode, the shift control unit 94 releases the first clutch C1 and activates the second clutch C2 while the dog clutch D1 is engaged. A CBD oil pressure control command signal Scbd is output to the oil pressure control circuit 52 for performing clutch-to-clutch gear shifting in which the clutch is gripped so as to be engaged. In this way, the shift control unit 94 performs an upshift, that is, a shift of the power transmission device 16 to switch from the gear running mode to the belt running mode, by the stepped shift control by disengaging the first clutch C1 and engaging the second clutch C2. Perform a gear upshift.

When the vehicle speed V increases in the belt running mode after the stepped upshift, the shift control unit 94 outputs a CBD hydraulic control command signal Scbd for releasing the dog clutch D1 to the hydraulic control circuit 52. On the other hand, if the vehicle speed V decreases in the belt running mode after the dog clutch D1 is released, the shift control unit 94 hydraulically controls the CBD hydraulic control command signal Scbd for engaging the dog clutch D1. Output to circuit 52.

When the shift control unit 94 determines a downshift while driving in the belt driving mode and switches to the gear driving mode, the shift control unit 94 releases the second clutch C2 and disengages the first clutch C1 while the dog clutch D1 is engaged. A CBD oil pressure control command signal Scbd is output to the oil pressure control circuit 52 for performing clutch-to-clutch gear shifting in which the clutch is gripped so as to be engaged. In this way, the shift control unit 94 downshifts the power transmission device 16 to switch from the belt running mode to the gear running mode by the stepped shift control by disengaging the second clutch C2 and engaging the first clutch C1. Perform a gear downshift.

In the belt running mode, the shift control unit 94 controls the primary pressure Ppri and the secondary pressure Psec so as to achieve the target gear ratio γcvttgt of the continuously variable transmission mechanism 24 while preventing belt slippage of the continuously variable transmission mechanism 24 from occurring. A CVT hydraulic control command signal Scvt for controlling the CVT hydraulic pressure control signal Scvt is output to the hydraulic control circuit 52 to execute the speed change of the continuously variable transmission mechanism 24. gear change control

Specifically, the shift control unit 94 applies the accelerator opening θacc and the vehicle speed V to a predetermined relationship, such as a CVT shift map, to determine the target primary rotation speed Npritgt (=target input shaft rotation speed Nintgt). calculate. The speed change control unit 94 calculates a target speed ratio γcvttgt (=Npritgt/Nsec) based on the target primary rotational speed Npritgt. The shift control unit 94 calculates an estimated engine torque Tee, which is an estimated value of the engine torque Te, by applying the throttle valve opening θth and the engine rotational speed Ne to the engine torque map, for example. The shift control unit 94 calculates an estimated input shaft torque Tine (=Tee×torque ratio t), which is an estimated value of the input shaft torque Tin (=turbine torque Tt), based on the estimated engine torque Tee. The shift control unit 94 uses a thrust ratio map having a predetermined relationship to realize the target gear ratio γcvttgt while preventing belt slippage based on the target gear ratio γcvttgt and the estimated input shaft torque Tine. Calculate the thrust ratio τ. The speed change control unit 94 calculates a target primary thrust Wpritgt and a target secondary thrust Wsectgt for achieving this thrust ratio τ. The shift control unit 94 converts the target primary thrust Wpritgt and the target secondary thrust Wsectgt into a target primary pressure Ppritgt (=Wpritgt/pressure receiving area) and a target secondary pressure Psectgt (=Wsectgt/pressure receiving area), respectively. The shift control unit 94 outputs a CVT hydraulic control command signal Scvt for controlling the primary pressure Ppri and the secondary pressure Psec to the hydraulic control circuit 52 so that the target primary pressure Ppritgt and the target secondary pressure Psectgt are obtained. In addition, in the description of the speed change control of the continuously variable transmission mechanism 24 mentioned above, for convenience, the thrust force for maintaining the target speed ratio γcvttgt constant was described. During a shift transition of the continuously variable transmission mechanism 24, a thrust force for achieving a target upshift or a target downshift is added to this thrust force for maintaining a constant state.

The lockup clutch control section 96 controls the control state of the lockup clutch 20lu. For example, the lock-up clutch control unit 96 can control a lock-up area line that has a predetermined relationship, for example, a release area corresponding to a released state, a slip area corresponding to a slip state, and an engagement area corresponding to an engaged state. In the figure, by applying the vehicle speed V and the accelerator opening θacc, it is determined which region it is in, and the control state corresponding to the determined region is realized.The LU oil pressure PRlu is supplied to the lock-up clutch 20lu. The LU hydraulic control command signal Slu is output to the hydraulic control circuit 52. By releasing the lock-up clutch 20lu, the torque converter 20 is brought into a torque converter state in which a torque amplification effect can be obtained. By engaging the lock-up clutch 20lu, the torque converter 20 is placed in a lock-up state in which the pump wheel 20p and the turbine wheel 20t are rotated together. When the lockup clutch 20lu is in a slip state, the lockup clutch 20lu is operated to slip so that the slip amount Nslp in the lockup clutch 20lu becomes the target slip amount Nslptgt. The slip amount Nslp is the differential rotational speed between the input and output (=Ne-Nin), which is the difference between the input and output rotational speeds of the lock-up clutch 20lu. When the lock-up clutch 20lu is in the slip state, when the vehicle 10 is in the driving state, the engine rotational speed Ne is suppressed from rising, and muffled noise inside the vehicle is suppressed. On the other hand, when the vehicle 10 is in the driven state, the engine 12 is rotated to follow the input shaft 22 at the target slip amount Nslptgt, and for example, the fuel cut region is expanded.

By the way, the power transmission device 16 is equipped with a gear mechanism 28 to improve fuel efficiency, and a gear ratio EL is set lower than the lowest gear ratio γmax of the continuously variable transmission mechanism 24. When the vehicle 10 starts to accelerate, the amount of increase in the input shaft rotational speed Nin with respect to the increase in the vehicle speed V becomes larger than the lowest side gear ratio γmax due to the gear ratio EL. Therefore, as the speed ratio e (=Nin/Ne) of the torque converter 20 increases, the torque ratio t of the torque converter 20 tends to decrease (see Fig. 2), making it difficult to obtain the torque amplification effect of the torque converter 20. There is a risk that In this case, there is a possibility that the vehicle acceleration G decreases significantly with respect to the increase in the vehicle speed V, resulting in deterioration of drivability. It is desirable to suppress a drop in vehicle acceleration G due to torque converter characteristics as vehicle speed V increases.

On the other hand, when the driver starts an acceleration operation, that is, starts the vehicle 10 when the accelerator is turned on, the engine control unit 92 performs a torque increase control CTtup that increases the requested engine torque Tedem more than the driver requested engine torque Tedemd. Implement. However, at the beginning of the start of the vehicle 10, the increase in the input shaft rotational speed Nin is smaller than the increase in the engine rotational speed Ne, so the torque amplification effect of the torque converter 20 is easily obtained, and the vehicle acceleration G is likely to increase. Therefore, after the vehicle 10 starts moving, there is no need to perform the torque increase control CTtup in a region where the input shaft rotational speed Nin is still low and where the vehicle acceleration G tends to increase. Furthermore, after the vehicle speed V increases by accelerating in response to the accelerator being turned on, the acceleration feeling, that is, the acceleration feeling, is unlikely to deteriorate even if the vehicle acceleration G does not increase. Therefore, after the start of the vehicle 10, there is no need to perform the torque increase control CTtup in a region where the vehicle speed V increases so that the acceleration feeling is unlikely to deteriorate, that is, in a region where the input shaft rotational speed Nin increases.

Therefore, when implementing the torque increase control CTtup, the engine control unit 92 determines that after the vehicle 10 starts due to the accelerator being turned on, the running state of the vehicle 10 is such that the torque amplification effect in the torque converter 20 increases as the input shaft rotational speed Nin increases. When a predetermined driving condition is reached in which it is difficult to obtain the required engine torque Tedem, the required engine torque Tedem is increased from the driver required engine torque Tedemd, for example, by a gradual increase until a second prescribed driving condition is reached in which the acceleration feeling is difficult to obtain. (i.e. sweep up). In the torque increase control CTtup, the engine control unit 92 sweeps up the requested engine torque Tedem from the driver requested engine torque Tedemd at a predetermined slope, for example. When the running state of the vehicle 10 reaches a second predetermined running state, the engine control unit 92 finishes sweeping up the requested engine torque Tedem, and thereafter, for example, changes the increase up to that point to the driver requested engine torque Tedem. Set the added required engine torque Tedem.

The electronic control device 90 further includes a state determining means, that is, a state determining section 98, in order to realize the function of torque increase control CTtup.

The state determining unit 98 determines whether or not the accelerator is turned on. If the state determining unit 98 determines that the accelerator is turned on, it determines whether the input shaft rotational speed Nin is within a predetermined range RNGf. The predetermined range RNGf is a predetermined range of the input shaft rotational speed Nin from the predetermined running state to the second predetermined running state of the vehicle 10. The state determination unit 98 determines whether the input shaft rotational speed Nin is within a predetermined range based on, for example, whether the input shaft rotational speed Nin is greater than or equal to the first predetermined rotational speed Ninf1 and less than the second predetermined rotational speed Ninf2. Determine whether The first predetermined rotational speed Ninf1 is, for example, a predetermined threshold value for determining that the running state of the vehicle 10 has reached a predetermined running state. Since the torque increase control CTtup is deactivated at the beginning of the start acceleration of the vehicle 10, the first predetermined rotation speed Ninf1 corresponds to the lower limit value of the input shaft rotation speed Nin at which the torque increase control CTtup is executed, that is, started. . The second predetermined rotational speed Ninf2 is, for example, a predetermined threshold value for determining that the running state of the vehicle 10 has reached a second predetermined running state. Since the torque increase control CTtup is deactivated when the starting acceleration of the vehicle 10 progresses, the second predetermined rotation speed Ninf2 corresponds to the upper limit value of the input shaft rotation speed Nin at which the torque increase control CTtup is executed, that is, terminated.

The engine control unit 92 implements the torque increase control CTtup when the state determination unit 98 determines that the input shaft rotational speed Nin is within the predetermined range RNGf. On the other hand, if the state determination unit 98 determines that the input shaft rotational speed Nin is not within the predetermined range RNGf, the engine control unit 92 does not perform the torque increase control CTtup.

During the implementation of lock-up clutch engagement control CTlu that switches the lock-up clutch 20lu from a released state to an engaged state including a slip state, the engine torque Te input to the lock-up clutch 20lu is increased in consideration of control accuracy. It is preferable not to interfere with the corresponding torque increase control CTtup. In other words, the torque increase control CTtup is preferably performed when the lock-up clutch 20lu is in the released state, where the torque converter 20 can obtain a torque amplification effect.

If the state determining unit 98 determines that the accelerator is turned on, it determines whether lock-up clutch engagement control CTlu has been started.

When the state determining unit 98 determines that the input shaft rotational speed Nin is within the predetermined range RNGf and that the lock-up clutch engagement control CTlu has not been started, the engine control unit 92 performs the following operations. Execute torque increase control CTtup. On the other hand, if the state determining unit 98 determines that the lock-up clutch engagement control CTlu has been started, the engine control unit 92 does not implement the torque increase control CTtup.

FIG. 3 is a flowchart illustrating the main part of the control operation of the electronic control device 90, and shows the deterioration of drivability due to the difficulty in obtaining the torque amplification effect of the torque converter 20 when the vehicle 10 starts with the accelerator being turned on. This is a flowchart illustrating a control operation for suppressing, for example, repeated execution. FIG. 4 is a diagram showing an example of a time chart when the control operation shown in the flowchart of FIG. 3 is executed.

In FIG. 3, first, in step S10 corresponding to the function of the state determining section 98 (hereinafter, step will be omitted), it is determined whether or not the accelerator is turned on. If the determination at S10 is negative, this routine is ended. If the determination in S10 is affirmative, it is determined in S20 corresponding to the function of the state determining section 98 whether or not the input shaft rotational speed Nin is within a predetermined range RNGf. If the determination at S20 is negative, S20 is repeatedly executed. If the determination in S20 is affirmative, it is determined in S30, which corresponds to the function of the state determining section 98, whether lock-up clutch engagement control CTlu has been started. If the determination at S30 is negative, torque increase control CTtup is implemented at S40, which corresponds to the function of the engine control section 92. Next, in S50 corresponding to the function of the state determining section 98, it is determined whether the input shaft rotational speed Nin is within a predetermined range RNGf. If the determination at S50 is affirmative, the process returns to S30. If the determination in S30 is affirmative, or if the determination in S50 is negative, the torque increase control CTtup is not performed in S60, which corresponds to the function of the engine control section 92. If the torque increase control CTtup is being executed, the torque increase control CTtup is ended.

FIG. 4 is a diagram showing an example of a case where the accelerator is turned on while the vehicle 10 is stopped, and the vehicle 10 starts and accelerates with the lock-up clutch 20lu released. In FIG. 4, time t1 indicates the time when the accelerator is turned on. After the accelerator is turned on, acceleration is performed with the accelerator opening degree θacc being substantially constant, and the vehicle speed V is increased. Specifically, the engine 12 is controlled so as to obtain the required engine torque Tedem corresponding to the accelerator opening degree θacc, that is, the driver requested engine torque Tedemd, and the engine rotational speed Ne is increased and the vehicle speed V due to the start acceleration of the vehicle 10 is increased. As the input shaft rotational speed Nin increases (see after time t1). In this embodiment, when the input shaft rotational speed Nin increases and falls within the predetermined range RNGf, the torque increase control CTtup is started (see time t2). In the torque increase control CTtup, as shown by the solid line, the requested engine torque Tedem is swept up from the driver requested engine torque Tedemd (see time t2 - time t3). In the comparative example shown by the broken line, the torque increase control CTtup is not implemented, so the increase in the engine rotation speed Ne is stagnant, and together with the increase in the input shaft rotation speed Nin, the torque amplification effect of the torque converter 20 is not achieved. As a result, the vehicle acceleration G decreases significantly. In this embodiment shown by the solid line, the engine rotational speed Ne is increased by implementing the torque increase control CTtup, making it easier to obtain the torque amplification effect of the torque converter 20, and suppressing a decrease in the vehicle acceleration G. In this embodiment, when the input shaft rotational speed Nin further increases and falls outside the predetermined range RNGf, the torque increase control CTtup is terminated (see time t3). In FIG. 4, as the vehicle speed V increases, an upshift is performed from the first gear in the gear running mode to the second gear in the belt running mode, and the lock-up clutch engagement control CTlu is implemented. The lock-up clutch 20lu is switched to the engaged state (see after time t3).

As described above, according to the present embodiment, after the vehicle 10 starts to move when the accelerator is turned on, the running state of the vehicle 10 changes such that the torque amplification effect in the torque converter 20 is difficult to obtain as the input shaft rotational speed Nin increases. When the predetermined driving state is reached, the requested engine torque Tedem is increased from the driver requested engine torque Tedemd until the second predetermined driving state is reached in which the feeling of acceleration is less likely to deteriorate. It is possible to suppress a drop in vehicle acceleration G due to accompanying torque converter characteristics. Therefore, it is possible to suppress deterioration of drivability due to difficulty in obtaining the torque amplification effect of the torque converter 20 when the vehicle 10 starts with the accelerator being turned on.

The power transmission device 16 is equipped with a gear mechanism 28 to improve fuel efficiency, and by implementing the torque increase control CTtup, it is possible to easily achieve both fuel efficiency and drivability.

Next, another embodiment of the present invention will be described. In the following description, parts that are common to the embodiments are designated by the same reference numerals, and the description thereof will be omitted.

In the first embodiment described above, the running state of the vehicle 10 from the predetermined running state to the second predetermined running state was determined based on whether the input shaft rotational speed Nin was within the predetermined range RNGf. Due to the stagnation in the increase in the engine rotational speed Ne and the increase in the input shaft rotational speed Nin, the speed ratio e of the torque converter 20 increases, and the torque ratio t of the torque converter 20 tends to decrease. Therefore, in this embodiment, the torque ratio t of the torque converter 20 decreases after the vehicle speed V increases due to accelerator ON until the running state of the vehicle 10 changes from a predetermined running state to a second predetermined running state. Judgment is based on whether

If the state determining unit 98 determines that the accelerator is turned on, it determines whether the vehicle speed V has increased. The state determining unit 98 determines whether the vehicle speed V has increased, for example, based on whether the vehicle speed V has become equal to or higher than a predetermined vehicle speed Vf. The predetermined vehicle speed Vf is a predetermined threshold value for determining, for example, the vehicle speed range at the beginning of the start of the vehicle 10 in which the vehicle acceleration G tends to increase.

If the state determination unit 98 determines that the vehicle speed V has increased, it determines whether the torque ratio t of the torque converter 20 has decreased. For example, the state determination unit 98 determines that the rate of change α (=dt/dt) of the torque ratio t calculated based on the speed ratio e of the torque converter 20 is a negative value, and the absolute value of the rate of change α is a predetermined rate of change. Based on whether or not the torque ratio t is equal to or greater than αf, it is determined whether the torque ratio t is decreasing.

When the state determination unit 98 determines that the torque ratio t of the torque converter 20 is decreasing, the engine control unit 92 performs torque increase control CTtup to compensate for the decrease in the torque ratio t. If the state determining unit 98 determines that the torque ratio t of the torque converter 20 is not decreasing, the engine control unit 92 determines that the decrease in the torque ratio t of the torque converter 20 has converged. In this case, the torque increase control CTtup is not performed.

When the lock-up clutch 20lu is switched from a released state to an engaged state including a slip state, the speed ratio e of the torque converter 20 is converged to "1", and the change in the torque ratio t of the torque converter 20 is converged. Therefore, it can be seen that determining whether the torque ratio t of the torque converter 20 is decreasing includes determining whether the lock-up clutch engagement control CTlu has not been started. .

FIG. 5 is a flowchart illustrating the main part of the control operation of the electronic control device 90, and shows the deterioration of drivability due to the difficulty in obtaining the torque amplification effect of the torque converter 20 when the vehicle 10 starts with the accelerator being turned on. This is a flowchart illustrating a control operation for suppressing, for example, repeated execution. FIG. 5 is a different embodiment from the flowchart of FIG. 3 in the first embodiment described above.

In FIG. 5, first, in S10B corresponding to the function of the state determining section 98, it is determined whether or not the accelerator is turned on. If the determination in S10B is negative, this routine is ended. If the determination at S10B is affirmative, it is determined at S20B, which corresponds to the function of the state determining section 98, whether the vehicle speed V has increased. If the determination at S20B is negative, S20B is repeatedly executed. If the determination at S20B is affirmative, it is determined at S30B, which corresponds to the function of the state determining section 98, whether the torque ratio t of the torque converter 20 is decreasing. If the determination in S30B is affirmative, torque increase control CTtup is implemented in S40B corresponding to the function of the engine control section 92. Then, the process returns to S30B. If the determination in S30B is negative, the torque increase control CTtup is not performed in S50B, which corresponds to the function of the engine control section 92. If the torque increase control CTtup is being executed, the torque increase control CTtup is ended.

As described above, according to this embodiment, similarly to the first embodiment described above, it is possible to suppress a drop in the vehicle acceleration G due to the torque converter characteristics as the vehicle speed V increases. Therefore, it is possible to suppress deterioration of drivability due to difficulty in obtaining the torque amplification effect of the torque converter 20 when the vehicle 10 starts with the accelerator being turned on. Further, by implementing the torque increase control CTtup, it is possible to easily achieve both fuel efficiency and drivability.

Although the embodiments of the present invention have been described above in detail based on the drawings, the present invention can also be applied to other aspects.

For example, in the first embodiment described above, S30 in the flowchart of FIG. 3 does not necessarily need to be provided when implementing the present invention. In the flowchart of FIG. 3, if S30 is not provided, if the determination in S20 is affirmative, S40 is executed, and if the determination in S50 is positive, the process returns to S40. Even in this case, it is possible to obtain a certain effect of suppressing a drop in the vehicle acceleration G due to the torque converter characteristics as the vehicle speed V increases.

Furthermore, in the embodiment described above, the vehicle 10 includes the power transmission device 16 in which the continuously variable transmission mechanism 24 and the gear mechanism 28 are provided in parallel in the power transmission path between the input shaft 22 and the output shaft 30. However, the present invention is not limited to this embodiment. The present invention is applicable to any vehicle equipped with an engine and a power transmission device having a torque converter connected to the engine and provided in a power transmission path between the engine and drive wheels. can. Further, although the torque converter 20 is provided with a lock-up clutch 20lu, this lock-up clutch 20lu does not necessarily need to be provided when implementing the present invention.

The above-mentioned embodiment is merely one embodiment, and the present invention can be implemented with various changes and improvements based on the knowledge of those skilled in the art.

10: Vehicle 12: Engine 14: Drive wheel 16: Power transmission device 20: Torque converter 90: Electronic control device (control device)

Claims (1)

A control device for a vehicle comprising an engine and a power transmission device provided in a power transmission path between the engine and drive wheels and having a torque converter connected to the engine, the control device comprising:
After the vehicle starts in response to the start of an acceleration operation by a driver, the vehicle is in a predetermined running state in which it becomes difficult to obtain a torque amplification effect in the torque converter as the output rotational speed of the torque converter increases. In this case, the requested value of the torque of the engine is increased from the value corresponding to the amount of acceleration operation by the driver until a second predetermined driving state is reached in which the feeling of acceleration is less likely to deteriorate. Characteristic vehicle control device.

Images