JP4077414B2 - Continuously variable transmission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a continuously variable transmission which materializes a vehicle system having safety and high fuel economy by the optimum control of transmission gear ratio of a CVT when stopping an engine during travel. <P>SOLUTION: In a shift from the engine stop to the neutral state, while changing transmission gear ratio of a CVT 4 to a target transmission gear ratio in accordance with vehicle speeds after a CVT-ECU 14 disengages a lock-up clutch of a torque converter 2 and a forward/reverse clutch 3, a control parameter of a feedback control circuit is changed to reset an integral term. At the same time, the CVT-ECU 14 calculates inertia torque from the change amount of target rotation speeds of a primary pulley 18. Hydraulic pressure PD is changed by the calculated inertia torque. By so doing, a clamp pressure required by a belt 20 is secured. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to a continuously variable transmission control device for a power train system including an engine and a continuously variable transmission.

Conventionally, there is a power train system in which a continuously variable transmission such as CVT (Continuously Variable Transmission) is combined with an engine, and this CVT has a belt between a primary pulley connected to an input shaft and a secondary pulley connected to an output shaft. And the hydraulic pressure is supplied to and discharged from the cylinders of the pulleys to change the widths of the grooves of the primary pulley and the secondary pulley relative to each other (see, for example, Patent Document 1).
JP-A-5-172229

On the other hand, there are idling stop systems and eco-run systems that stop the engine when the vehicle is stopped (vehicle speed = 0 [km / h]) and improve fuel efficiency by reducing fuel consumption. A power train system combining such a system with the CVT described above is an oil pump driven by engine power to supply various hydraulic pressures for controlling the CVT when the engine is restarted and started. Separately, an electric oil pump driven by a motor is provided.
Conventionally, the above-mentioned electric oil pump has not been able to supply a hydraulic pressure that is high enough to be supplied by a mechanical oil pump. Therefore, the required hydraulic pressure cannot be secured only by the hydraulic pressure supplied by the electric oil pump. Therefore, it is necessary to drive the electric oil pump only when the vehicle is at a standstill when the hydraulic pressure required for the control is small, start the engine in other travel areas, and supply the hydraulic pressure by the mechanical oil pump. It was. Because of such a problem, in the power train system provided with the CVT, eco-run control is performed in which the engine is stopped only when the vehicle is stopped.

However, in recent years, improvement and improvement of electric oil pumps have progressed, and even with electric oil pumps, it has been possible to supply high hydraulic pressure, exhibiting performance comparable to mechanical oil pumps driven by engine power. In a hybrid vehicle in which the front drive wheels are driven by a power train consisting of an engine equipped with an eco-run system and a CVT and the rear drive wheels are driven by a motor, the front engine is stopped and the front motor is driven only by the rear motor. The CVT clutch can be disengaged and the continuously variable transmission can be controlled.
Even in the conventional eco-run system, the CVT clutch can be disengaged and the speed change control of the continuously variable transmission can be performed even if the eco-run range is expanded until the vehicle is running, such as when the engine is stopped when the accelerator is off. It became.

  However, as described above, the engine is stopped during traveling, and the clutch that connects the CVT and the engine is released to achieve a neutral state. Then, the engine is restarted and the clutch is engaged to set the engine torque to CVT. If the CVT gear ratio is high (low gear state) and the clutch is engaged when the engine is restarted, the engine speed will rise rapidly or the engine will There were problems such as braking.

  The present invention has been made in view of the above problems, and when the engine is stopped during traveling, a safe and fuel-efficient vehicle system can be constructed by optimally controlling the CVT gear ratio. An object is to provide a continuously variable transmission control device.

The continuously variable transmission control device (1) according to the present invention includes:
The engine can be stopped even when the vehicle is traveling. When the engine is stopped while traveling, hydraulic oil is supplied to the pulley when shifting to the high gear ratio side, and A continuously variable transmission control device in a vehicle system that releases engagement means provided between a continuously variable transmission from which hydraulic oil is discharged when shifting to a speed ratio side and an engine, and
When the engine is stopped and the vehicle is in a stopped state, the gear ratio of the continuously variable transmission is controlled to a first gear ratio that is a high gear ratio, and when the engine is stopped and the vehicle is in a traveling state, Control means for controlling to a second speed ratio lower than the first speed ratio,
The second gear ratio in the control means is controlled so that the lower the gear ratio is, the higher the vehicle speed is, and the lower speed ratio is set wider than the high speed ratio. With
The control means is characterized in that, when the speed ratio is controlled when the engine is stopped, the responsiveness of the speed change is lowered compared to when the speed ratio is controlled when the engine is driven .

Furthermore, the continuously variable transmission control device (2) according to the present invention includes a continuously variable transmission control device (1),
The control means is characterized in that when the speed ratio is controlled when the engine is stopped, a limit is set for a shift amount that can be shifted within a predetermined time.

Further, the continuously variable transmission control device (3) according to the present invention includes a continuously variable transmission control device (1),
When the speed ratio is controlled when the engine is stopped, the control means changes the target value of the speed change control more smoothly than when the speed ratio is controlled when the engine is driven. Features.

Furthermore, the continuously variable transmission control device (4) according to the present invention includes a continuously variable transmission control device (1),
The control means clears the integral term in the feedback control performed in the shift control when the shift control is switched between a state where the engine is driven and a state where the engine is stopped.

A continuously variable transmission control device (5) according to the present invention is a continuously variable transmission control device (1).
When the shift control is switched between a state where the engine is driven and a state where the engine is stopped, the control means determines the clamping force of the pulley of the continuously variable transmission according to the change speed of the speed ratio before and after the switch. It is characterized by changing.

Furthermore, the continuously variable transmission control device (6) according to the present invention includes a continuously variable transmission control device (5),
A restriction is provided so that the clamping force of the pulley does not exceed a clamping force that can be realized by an oil pump that drives the pulley.

A continuously variable transmission control device (7) according to the present invention includes a continuously variable transmission control device (1),
When the engine is started after the engine is stopped and the vehicle is stopped, the control means controls the engine-side rotation speed of the continuously variable transmission until the engine starts and the engagement means completes engagement. Is characterized in that the gear ratio is controlled so that is close to the idle speed.

According to the continuously variable transmission control device (1) according to the present invention, when the engine is stopped and the vehicle is stopped, the transmission ratio of the continuously variable transmission is controlled to the first transmission ratio that is a high transmission ratio. When the engine is stopped and the vehicle is in a running state, the speed is controlled to a speed ratio lower than the first speed ratio and changed according to the vehicle speed. When the vehicle speed is high, the transmission ratio of the continuously variable transmission is controlled to a low value, and the engine speed can be prevented from being increased when the clutch is engaged. Furthermore, in the case of a continuously variable transmission that uses hydraulic pressure to shift, the shift speed when shifting from the lowest gear ratio to the highest gear ratio is faster than the shift speed from the highest gear ratio to the lowest gear ratio. If the control is performed so as to be in the gear ratio, an effect of quick response can be obtained.

Further, according to the continuously variable transmission control device (1) according to the present invention, when the speed ratio is controlled when the engine is stopped, when the speed ratio is controlled when the engine is driven, Since the speed change responsiveness is lowered by changing the speed change control parameters, the speed of the speed change due to the clutch release when the engine is stopped while traveling is reduced, and the driver can be prevented from feeling uncomfortable.

Furthermore, when shifting is controlled by a hydraulic actuator such as a duty solenoid, if the shifting control output is increased, a large amount of hydraulic pressure is supplied to the shifting control unit, and another hydraulic control is performed by the flow rate balance in the hydraulic control device. However, according to the continuously variable transmission control device (2) of the present invention, when the speed ratio is controlled when the engine is stopped, it is within a predetermined time. Since the shift amount that can be shifted is limited, it is possible to prevent the shift amount from increasing.

Also, when switching the target rotation speed by switching the shift control mode, if the target value is switched stepwise, the deviation between the target rotation speed and the actual rotation speed at the time of switching increases, so the output value also increases at once. However, according to the continuously variable transmission control device (3) according to the present invention, the gear ratio is controlled when the engine is stopped. In some cases, the target value of the speed change control can be changed more smoothly when the speed ratio is controlled when the engine is driven, so that the deviation between the target speed and the actual speed is prevented from increasing. be able to.

Furthermore, when the target speed is switched, the integrated value (sum) of the deviation before the target speed is switched remains in the feedback calculation unit, and even if the deviation becomes 0, an output is generated, so that the shift is followed. However, according to the continuously variable transmission control device (4) according to the present invention, the engine is driven and the engine is stopped. When the shift control is switched at, the integral term in the feedback control performed in the shift control is cleared, so that it is possible to prevent the follow-up performance of the shift from being deteriorated.

When the target speed (target speed ratio) is switched, the speed ratio changes. As a result, the primary pulley speed of the continuously variable transmission continuously increases and decreases, and this change in rotation causes the inertia of the continuously variable transmission. Torque is generated. The belt clamping force of the continuously variable transmission is controlled to the minimum necessary pressure, but if the primary pulley rotation speed of the continuously variable transmission changes in a decreasing direction, this inertia torque is a positive value. Therefore, an inertia torque is applied to the contact point between the pulley and the belt of the continuously variable transmission, so that a necessary clamping pressure cannot be secured and the belt slips. On the other hand, when the primary pulley rotation speed of the continuously variable transmission changes in an increasing direction, the inertia torque becomes a negative value, so the normal pressure is more than necessary, and an unnecessary load is applied to the belt. There was a fear. However, according to the continuously variable transmission control device (5) according to the present invention, when the shift control is switched between the state in which the engine is driven and the state in which the engine is stopped, the speed of change of the gear ratio before and after the switching is increased. Accordingly, since the clamping force of the pulley of the continuously variable transmission is changed, it is possible to prevent the belt from slipping and to prevent an unnecessary load from being applied to the belt.

Furthermore, even if the hydraulic pressure is set by changing the inertia, if the engine stops and the line pressure PL of the hydraulic control device is small, or if the hydraulic pressure cannot be raised above a predetermined value due to the structure of the hydraulic control device, Although the actual hydraulic pressure cannot be increased as intended, according to the continuously variable transmission control device (6) of the present invention, the clamping force of the pulley exceeds the clamping force that can be achieved by the oil pump that drives the pulley. If the clamping pressure command becomes larger than the maximum supply pressure of the oil pump, the inertia torque can be suppressed by limiting the change speed of the gear ratio, for example, and reducing the rotation speed. In addition, the belt can be prevented from slipping.

Also, if the engine is started and a downshift is applied before the clutch is engaged, the engine speed and the CVT primary pulley speed will be greatly separated, and the clutch engagement response will deteriorate. According to the continuously variable transmission control device (7) of the present invention, when the engine is started after the engine is stopped and the vehicle is stopped, the engine is started and the engagement means completes the engagement. Meanwhile, since the gear ratio is controlled so that the engine side rotational speed of the continuously variable transmission is close to the idle rotational speed, the response of the clutch engagement can be improved.

The continuously variable transmission control device of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing an overall system of a hybrid vehicle to which a continuously variable transmission control device of the present invention is applied. In this hybrid vehicle, an engine 1 drives front drive wheels, and a motor / generator 7 drives rear drive wheels. To do. That is, the engine 1 drives the front drive wheels 6 via the torque converter 2, the forward / reverse clutch 3, the continuously variable transmission (hereinafter referred to as CVT) 4, and the gear 5, and the motor / generator 7 directly drives the rear drive wheels 8. To drive.

  The hybrid vehicle includes a hybrid system electronic control unit (hereinafter referred to as HV-ECU) 12, an engine electronic control unit (hereinafter referred to as ENG-ECU) 13, a torque converter 2, a forward / reverse clutch 3, and a CVT electronic control that controls CVT 4. The apparatus includes four control devices, a device (hereinafter referred to as CVT-ECU) 14 and a motor / generator electronic control device (hereinafter referred to as MG-ECU) 15 that controls the motor / generator 7. A mode (hereinafter referred to as an ENG mode), a mode in which the engine 1 is stopped and the vehicle is driven only by the driving force of the motor / generator 7 (hereinafter referred to as an EV mode), and the engine 1 is stopped and the motor / generator 7 is stopped. Mode that collects electric energy by the above (hereinafter referred to as regenerative mode) It has become possible.

The torque converter 2, the forward / reverse clutch 3 and the CVT 4 are provided with a hydraulic control device 9 controlled by the CVT-ECU 14, and the hydraulic control device 9 has a mechanical oil pump 10 driven by the engine 1 and a hydraulic pressure when the engine is stopped. The electric oil pump 11 to be supplied is connected, and these oil pumps generate a line pressure PL for operating the torque converter 2, the forward / reverse clutch 3, and the CVT 4. Thus, since the electric oil pump 11 is provided, the forward / reverse clutch 3 can be engaged even when the engine 1 is stopped.
The hydraulic control device 9 includes an electromagnetic switching valve, a linear solenoid valve, and the like, and controls the solenoid to switch the oil path and control the hydraulic pressure, thereby switching the transmission ratio of the CVT 4 and engaging / disengaging the clutch. Release.

Further, the motor / generator 7 is connected to the battery 17 via the inverter 16, and is supplied with electric energy from the battery 17 in accordance with the control of the MG-ECU 15 and driven to rotate at a predetermined torque (EV mode) and by regenerative braking. By functioning as a generator, the battery 17 is switched between a state in which electric energy is charged to the battery 17 (regeneration mode) and a no-load state in which the motor shaft is allowed to freely rotate (free).
In the above regeneration mode, the torque for forcibly rotating the motor / generator 7 becomes the braking torque, and so-called engine braking can be applied. In this case, the transmission of torque between the output shaft and the engine 1 is cut off, so that the engine is not brought in. Therefore, the energy regeneration can be efficiently performed with the power loss minimized.

  On the other hand, the torque converter 2 is provided with a lock-up clutch, a turbine impeller is connected to the input shaft of the forward / reverse clutch 3, and the lock-up clutch is engaged / released by a hydraulic pressure PLU from the hydraulic control device 9. . A forward / reverse clutch 3 capable of disconnecting forward / reverse switching and transmission of driving force to the output shaft of the torque converter 2 and forming a neutral state is connected to the output shaft of the torque converter 2. 3 is engaged / released.

  The CVT 4 connected to the output shaft of the forward / reverse clutch 3 is configured by a transmission belt 20 being stretched between a primary pulley 18 and a secondary pulley 19, and the rotation input to the input shaft is a coaxial pulley integrated primary pulley. 18 is transmitted to the secondary pulley 19 via the speed change belt 20 and output to the output shaft.

  FIG. 2 is a diagram illustrating a configuration of a hydraulic control unit for controlling the continuously variable transmission unit of the CVT 4, and the CVT-ECU 14 performs a DUTY command to the DUTY solenoids DS 1 and DS 2 provided in the hydraulic control device 9. Controls the gear ratio of CVT4. In FIG. 2, when the DUTY solenoid DS1 is driven, the upshift (speed change) hydraulic valve V1 is driven to supply hydraulic oil to the primary pulley 18, the primary oil chamber is filled with hydraulic oil, and the groove width of the pulley. Is narrowed, the applied diameter of the speed change belt 20 changes, and as a result, an upshift (accelerated speed change) is performed.

On the other hand, when the DUTY solenoid DS2 is driven, the downshift (deceleration shift) hydraulic valve V2 is driven, the hydraulic oil in the primary pulley oil chamber is discharged, and the groove width of the pulley is widened. Change, and as a result, downshift (deceleration shift).
The secondary pulley oil chamber of the secondary pulley 19 is supplied with a secondary pulley pressure PD for clamping the speed change belt 20 sandwiched between the secondary pulleys 19.

  The output value DUTY of the DUTY command for the DUTY solenoids DS1 and DS2 is calculated by the CVT-ECU 14 using the following feedback calculation formula.

Here, Kp is a proportional gain, TI is an integration time, TD is a differentiation time, γtgt is a target gear ratio, and γreal is an actual gear ratio.
The above equation (1) is a basic equation for feedback control. However, in the case of a digital arithmetic device that performs control operation using a microcomputer as in this embodiment, the operation is not performed continuously. Since the calculation is performed every period ΔT, it is general to use the feedback control equation after converting it as shown in the following equation (2).

Here, the respective terms in the expression (2) are called a proportional term (first term), an integral term (second term), and a differential term (third term) in order from the first term. Further, the speed ratio γ can be expressed as follows using the rotational speed Nin of the primary pulley 18 and the rotational speed Nout of the secondary pulley 19.
γ = Nin / Nout
Therefore, the control amount can also be expressed as follows using the target rotational speed Nintgt and the actual rotational speed Ninreal from the relationship of the above equation (2).

  In the following description, an embodiment will be described in which the CVT-ECU 14 calculates the output value DUTY based on the feedback calculation formula of the above formula (2) or formula (3), but the speed ratio γ is abstract. Since it is a variable, it is easier to design the controller by performing the calculation using the above equation (3) that represents the control amount by the CVT primary pulley rotation speed, which is usually the same rotation speed as the engine rotation speed. Accordingly, in the following description, the description will be made mainly based on Expression (3).

  On the other hand, FIG. 3 is a diagram showing signals transmitted by multiplex communication between the ECUs of the control device of the hybrid vehicle. The HV-ECU 12 includes various sensors including an idle switch state, an engine speed, a vehicle speed, and a brake switch state. Based on the information from "0: Ignition off (IGOFF)", "1: In operation", "2: Stop request", "3: Stop control" shown in the state transition diagram of the engine operation mode in FIG. The engine operation mode and the travel mode of “medium” and “4: start request” are determined, and the engine control mode, EV travel mode request, and regenerative travel mode request commands are sent to the ENG-ECU 13, CVT-ECU 14, and MG-ECU 15 I do. Further, the ENG-ECU 13 controls the throttle opening, ignition timing, fuel injection valve, intake / exhaust valve, and the like based on information from various sensors including the engine control mode, the accelerator opening, and the idle switch state. To control.

  Further, the CVT-ECU 14 engages / releases the lock-up clutch and the forward / reverse clutch 3 of the torque converter 2 and the CVT 4 based on information from various sensors including the engine control mode, shift lever selection position, engine speed, and vehicle speed. And a signal such as an engine stop prohibition request, an engine speed control request, and a target engine speed are transmitted to the ENG-ECU 13. In the EV mode, the MG-ECU 15 drives the motor / generator 7 with the electric power from the battery 17 by the inverter 16 and charges the battery 17 with the regenerative electric power from the motor / generator 7 through the inverter 16 in the regenerative mode. .

  Further, in performing the clutch control, the CVT-ECU 14 defines each control state as a clutch control mode, and, as shown in the state transition table of the clutch control mode in FIG. The engine has five clutch control modes including “1: preparation for release”, “2: release control”, “3: release”, and “4: engagement control”. The engine control mode and EV travel from the HV-ECU 12 A clutch release / engagement control mode is determined based on the mode flag / regenerative travel mode flag. That is, the CVT-ECU 14 shifts each clutch control mode to another clutch control mode when the transition conditions shown in the table of FIG. 6 are satisfied.

Next, the clutch control and the CVT shift control when the operation mode is changed will be described with reference to the clutch control mode transition condition table of FIG. 6 and the flowcharts of FIGS. 7-1 to 7-3.
The CVT-ECU 14 executes the program shown in the flowcharts of FIGS. 7-1 to 7-3 at regular intervals using a timer or the like. When the execution of this process starts, the CVT-ECU 14 first sets the clutch control mode to “0”. : Control not executed "is determined (step 101). If the clutch control mode is not “0: control not executed”, the routine proceeds to step 104.

On the other hand, when the clutch control mode is “0: control not executed”, the CVT-ECU 14 determines whether or not the transition condition [1] is satisfied (step 102). If the transition condition [1] is not satisfied, the process proceeds to step 104. If the transition condition [1] is satisfied, the CVT-ECU 14 changes the clutch control mode from “0: no control execution” to “1: release preparation”. The process proceeds to “medium” (step 103).
That is, as shown in [1] of the transition condition table of FIG. 6, when the engine control mode transits from “1: driving” to “2: stop request”, the EV driving mode flag is on. When it is determined that the drive is switched to the motor / generator 7 only, or when the regenerative travel mode flag is on, the control shifts to the clutch release control, and the clutch control mode is changed from “0: control not executed”. Move to “1: Preparing for release”.

Next, the CVT-ECU 14 determines whether or not the clutch control mode is “1: preparation for release” (step 104). When the clutch control mode is “1: Preparing for release”, the CVT-ECU 14 determines whether or not the transition condition [6] is satisfied (step 105). If the transition condition [6] is satisfied, the CVT-ECU 14 shifts the clutch control mode from “1: preparing for release” to “0: no control execution” (step 106), and then proceeds to step 131.
That is, as shown in [6] of the transition condition table of FIG. 6, when the engine control mode has been changed to “1: In operation” or “4: Start request”, or EV travel mode request, regenerative travel When the vehicle speed is less than the predetermined value and the brake is on, not the mode request, the clutch control mode is shifted from “1: Preparing for release” to “0: Control not executed”. Further, even when the clutch lever is in the neutral or P range, control is impossible, and the clutch control mode is shifted from “1: preparing for release” to “0: control not executed”.

  On the other hand, if the transition condition [6] is not satisfied in step 105, the CVT-ECU 14 makes a release control of the lockup clutch and makes an engine stop prohibition request to the ENG-ECU 13 (step 107). The release control of the lockup clutch and the release clutch 3 are performed after releasing the lockup clutch after releasing the lockup clutch without simultaneously releasing the forward / reverse clutch 3 and the lockup clutch. This is because it may not be possible to perform both simultaneously, and if two clutches arranged on the same axis are operated simultaneously, it is difficult to determine whether to release the respective clutches, and the control becomes unstable. The reason why the engine stop prohibition request is issued to the ENG-ECU 13 is to prevent the engine 1 from stalling in the middle.

  If this clutch control mode is the start by the EV travel mode flag, the driver is willing to perform a constant travel only by the accelerator operation, and therefore a shock due to the release of the lockup clutch cannot be allowed. For this reason, when the start is based on the EV travel mode flag, in order to release the lockup clutch smoothly, the lockup clutch pressure PLU as shown in the hydraulic pressure PLU of the clutch control chart by the EV travel mode transition of FIG. The lockup clutch is released smoothly without shock.

  On the other hand, when the control is started by the regenerative travel mode flag, the driver also performs the brake operation and seems to be willing to stop, so some shock is allowed. Therefore, if the start is based on the regenerative travel mode flag, the lockup clutch is suddenly released and the forward / reverse clutch 3 is quickly released as shown in the hydraulic pressure PLU of the clutch control chart by the regenerative travel mode transition in FIG. Move to release.

  When the lockup clutch is released, the CVT-ECU 14 performs control to synchronize the engine speed and the input shaft speed of the CVT 4 (step 108). This is because when the forward / reverse clutch 3 is disengaged, a shock due to the clutch disengagement will occur if there is a driving / driven state in which there is a difference between the rotational speed of the engine 1 and the input shaft rotational speed of the CVT 4. -The ECU 13 synchronizes the engine speed and the CVT input shaft speed using an electronic throttle or the like.

Next, the CVT-ECU 14 determines whether or not the transition condition [2] is satisfied (step 109). If the transition condition [2] is not satisfied, the process proceeds to step 131. On the other hand, when the transition condition [2] is satisfied, the CVT-ECU 14 changes the clutch control mode from “1: preparing for release” to “2: releasing control” (step 110), and then proceeds to step 131. .
That is, as shown in [2] of the transition condition table of FIG. 6, the release of the lockup clutch is confirmed, and the state where the deviation between the rotational speed of the engine 1 and the rotational speed of the input shaft of the CVT 4 is small continues for a predetermined time. When the control mode is “2: stop request” and the travel mode is the EV travel mode or the regenerative travel mode, the CVT-ECU 14 changes the clutch control mode from “1: preparing for release” to “2”. : "Under release control"

  On the other hand, if it is determined in step 104 that the clutch control mode is not “1: preparation for release”, the CVT-ECU 14 determines whether the clutch control mode is “2: release control in progress” (step 111). ). When the clutch control mode is “2: during release control”, the CVT-ECU 14 determines whether or not the transition condition [7] is satisfied (step 112). When the transition condition [7] is satisfied, that is, when the clutch lever is in the neutral or P range, control is impossible, so the clutch control mode is changed from “2: release control in progress” to “0: control not executed”. (Step 113), the process proceeds to Step 131.

  If the transition condition [7] is not satisfied in step 112, the CVT-ECU 14 gradually decreases the clutch pressure PC1 of the forward / reverse clutch 3 (step 114). As a result, the forward / reverse clutch 3 is gradually released. Also in this case, as in the case of releasing the lockup clutch, when the clutch control mode is started by the EV travel mode flag, as shown in the clutch control chart by the EV travel mode transition in FIG. When the control is started by the regenerative travel mode flag, as shown in the clutch control chart by transition to the regenerative travel mode in FIG. The clutch can be released quickly.

Next, the CVT-ECU 14 makes an engine control mode transition prohibition request (step 115).
Here, the engine control mode transition prohibition requires processing such as re-engagement of the clutch when the engine control mode transitions while the clutch hydraulic pressure PC1 of the forward / reverse clutch 3 is gradually decreased. This is because the vehicle behavior is also affected and the control becomes busy, so that stable control is maintained. When the release of the forward / reverse clutch 3 is started, the CVT-ECU 14 controls the HV-ECU 12 in the engine control mode. Request a transition prohibition.

  Next, the CVT-ECU 14 determines whether or not the transition condition [3] is satisfied (step 116). If the transition condition [3] is not satisfied, the process proceeds to step 131. On the other hand, when the transition condition [3] is satisfied, that is, when it is determined that the forward / reverse clutch 3 has been released, the CVT-ECU 14 changes the clutch control mode from “2: release control in progress” to “3: release”. (Step 117). Next, the engine control mode transition prohibition and engine stop prohibition requests are canceled and the electric oil pump 11 is started to be driven (step 118), and then the process proceeds to step 131. Since the engine is completely stopped by releasing the engine stop prohibition request and the engine is stopped, the mechanical oil pump 10 that is a hydraulic pressure supply source is also stopped. Therefore, the electric oil pump 11 is driven to continue the pressure control. To do.

  When determining whether the forward / reverse clutch 3 has been released, if the engine speed and the CVT input shaft speed are controlled synchronously as described above, the clutch release cannot be determined based on the engine speed. The release of the forward / reverse clutch 3 is determined. However, since the actual PC1 pressure has a response delay with respect to the PC1 command pressure, the actual PC1 pressure when the PC1 command pressure is equal to or lower than the predetermined oil pressure continues for a predetermined time, that is, at time t1 in FIGS. Therefore, it is determined that the clutch has been released. Since the response delay changes depending on the oil temperature, the predetermined time is changed according to the oil temperature.

  On the other hand, if it is determined in step 111 that the clutch control mode is not “2: release control in progress”, the CVT-ECU 14 determines whether or not the clutch control mode is “3: release” (step 119). When the clutch control mode is “3: release”, the CVT-ECU 14 determines whether or not the transition condition [8] is satisfied (step 120). When the transition condition [8] is satisfied, that is, when the clutch lever is in the neutral or P range, control is impossible, so the clutch control mode is shifted from “3: release” to “0: control not executed”. After (step 121), the process proceeds to step 131.

  In step 120, when the transition condition [8] is not satisfied, the CVT-ECU 14 holds the hydraulic pressure command value at the time of releasing the clutch of the forward / reverse clutch (step 122). This is because if the PC1 pressure is 0, the hydraulic oil is released from the clutch oil chamber of the forward / reverse clutch 3 and the hydraulic oil needs to be filled into the clutch oil chamber when the forward / backward clutch 3 is engaged next time. This is because the hydraulic oil in the clutch oil chamber is kept full so that there is no response delay in the engagement time of the clutch.

Next, the CVT-ECU 14 determines whether or not the transition condition [4] is satisfied (step 123). If the transition condition [4] is not satisfied, the process proceeds to step 131. On the other hand, when the transition condition [4] is satisfied, that is, when the engine control mode is “4: start request” and the electric oil pump 11 is operating normally, the CVT-ECU 14 switches to the clutch control mode. After shifting from “3: release” to “4: engaged control” (step 124), the process proceeds to step 131.
When it is determined in step 123 that the electric oil pump is stopped for some reason, the engine is started first, and the CVT-ECU 14 is in a state where the engine speed is equal to or higher than a predetermined speed. After determining that the mechanical oil pump 10 can supply a stable hydraulic pressure, the clutch control mode is shifted from “3: release” to “4: engaged control”.

  If it is determined in step 119 that the clutch control mode is not “3: release”, the CVT-ECU 14 determines whether or not the clutch control mode is “4: engaged control” (step 125). If the clutch control mode is not “4: engaged control”, the routine proceeds to step 131. On the other hand, when the clutch control mode is “4: engaged control”, the CVT-ECU 14 performs synchronous control of the rotational speed of the engine 1 and the input shaft rotational speed of the CVT 4 and prohibits the engine from being stopped with respect to the ENG-ECU 13. A request is made (step 126).

As in the case of release, the above-mentioned rotation speed synchronization control is performed when the driving / driven state is such that there is a difference between the engine rotation and the CVT input shaft rotation before and after the clutch is engaged. It is because it comes out.
The ENG-ECU 13 starts the engine at the time of transition to the ENG mode. However, if the rotational speed of the engine 1 is made to follow the actual input shaft rotational speed of the CVT 4, the engine is caused by vibration of the input shaft rotational speed of the CVT 4 or the like. Since there is a risk of vibration up to the number of revolutions, the target primary pulley revolution number for the continuously variable transmission during clutch engagement control is calculated based on the requested output calculated from the engine torque estimated based on the accelerator operation amount and the vehicle speed. Then, the engine speed is controlled so that the rotation ratio between the continuously variable transmission target primary pulley speed and the engine speed becomes 1.0. Further, the CVT-ECU 141 performs the shift control of the CVT 4 so that the primary pulley rotational speed follows the continuously variable transmission target primary pulley rotational speed.

  Next, the CVT-ECU 14 determines whether or not the deviation between the rotational speed of the engine 1 and the input shaft rotational speed of the CVT 4 has continued for a predetermined time (step 127). Move to step 131. On the other hand, when the state where the rotational speed deviation is not more than the predetermined value continues for a predetermined time, the CVT-ECU 14 engages the forward / reverse clutch by gradually increasing the clutch pressure PC1 of the forward / reverse clutch 3, and at the time of release. Similarly to the above, in order to perform the control stably, the engine control mode transition is prohibited for the HV-ECU 12 (step 128).

  Next, the CVT-ECU 14 determines whether or not the transition condition [5] is satisfied (step 129). If the transition condition [5] is not satisfied, the process proceeds to step 131. On the other hand, when the transition condition [5] is satisfied, that is, when the completion of engagement of the forward / reverse clutch 3 is determined, or when the clutch lever is switched to the neutral or P range, the CVT-ECU 14 is locked up. After releasing the clutch engagement permission, engine control mode transition prohibition and engine stop prohibition requests, the clutch control mode is changed from “4: engaged control” to “0: control not executed” (step 130). Move to step 131.

  Even when the completion of the engagement of the forward / reverse clutch 3 is determined, since the engine rotational speed and the input shaft rotational speed of the CVT 4 coincide with each other, it is impossible to determine whether the clutch engagement is completed based on the rotational speed. That is, based on the clutch hydraulic pressure command value, that is, after a predetermined time has elapsed after the clutch pressure PC1 becomes the engagement command value, it is determined that the engagement is completed at time t2 in FIGS. Also in this case, similar to the clutch release, since the responsiveness changes depending on the oil temperature of the hydraulic oil, the predetermined time is changed depending on the oil temperature.

  Next, the CVT-ECU 14 determines whether the engine is stopped and the clutch is in a released state (step 131). When the engine is stopped and the clutch is in the released state, the CVT-ECU 14 sets the target gear ratio γtgt of the CVT 4 to a gear ratio set from a target value different from the normal mode (step 132). The target gear ratio γtgt at this time is determined by a map shown in FIG. 10A in which the target gear ratio is calculated from the vehicle speed. In this map, as shown in the figure, the target speed ratio γtgt is set back to the maximum speed ratio (γmax) at low speeds, and is set to the minimum speed ratio (γmin) at high speeds. This is because when the engine is started and returned during running, if the gear ratio γ is a large value, the engine speed increases when the clutch is engaged. In addition, in the case of a CVT that performs a shift using hydraulic pressure, there is also a characteristic that the shift speed when shifting from γmin to γmax is faster than the shift speed from γmax to γmin. It is better to have a better response. The setting of the target gear ratio may be a map setting as the target rotational speed as shown in FIG. 10B. In the following description, a case where the target rotational speed Nintgt is controlled will be described.

  When switching the gear ratio control, if the target value is switched stepwise, the deviation at the time of switching (= target rotation speed−actual rotation speed) increases, so there is a risk of shifting hunting and overshooting. In the case of switching, the CVT-ECU 14 sets the target rotational speed Nintgt so as to continuously switch at a predetermined inclination as shown in FIG. Note that the shift tracking performance varies depending on parameters such as the oil temperature of the hydraulic oil and the CVT input shaft rotation speed, so the predetermined inclination is changed depending on parameters such as the oil temperature of the hydraulic oil and the CVT input shaft rotation speed. Set to a constant.

Next, the CVT-ECU 14 changes the feedback gain based on the feedback arithmetic expression of the equation (3) to a setting different from that in the normal time and limits the output value DUTY output to the shift control unit so as not to exceed a certain value ( Step 133).
Unlike a normal shift, a shift by releasing the clutch when the engine is stopped during travel requires that the speed of the shift be reduced so that the driver does not feel uncomfortable. For this reason, the CVT-ECU 14 sets the speed change speed by setting the feedback gain of the feedback calculation formula (3) different from the normal time, for example, by reducing the proportional gain Kp and the differential time TD or increasing the integral time TI. Reduce the feeling of discomfort given to the driver.

  Further, as described above, even if the feedback gain is set differently, if the control deviation increases, the output value also increases accordingly. In the case of a system in which the shift is controlled by a hydraulic actuator such as a duty solenoid, if a large shift control output is output, a large amount of hydraulic pressure is supplied to the shift control unit, and the pressure of other hydraulic control units as described above. In particular, when the engine is stopped and the hydraulic pressure is supplied by the electric oil pump 11, this possibility is particularly likely to occur. For this reason, the CVT-ECU 14 sets a threshold value for the output value DUTY of the feedback calculation formula (3) based on the oil temperature, the line pressure PL which is the original pressure of the hydraulic pressure control device 9 supplied by the oil pump, and the centrifugal hydraulic pressure due to the pulley rotation. The output value DUTY is kept below the above threshold. The line pressure PL can be predicted from the measured value of the hydraulic sensor that measures the hydraulic pressure PD of the output shaft pulley 19, the PD command value, and the like.

Next, the CVT-ECU 14 clears the integral term of the feedback control only when the gear ratio control is switched (step 134).
The integral term of the feedback control is to integrate the deviation and reflect it in the output value in order to make the deviation (= target rotational speed-actual rotational speed) 0, but it is integrated due to the influence of the deviation before switching the target rotational speed. If the terms are in an accumulated state, problems such as deterioration in follow-up performance of the shift and overshooting occur. For this reason, when the CVT-ECU 14 performs switching of the target rotation speed, the value of the integral term (second term) of the computation unit that performs the feedback computation of Expression (3) is as shown in FIG. Once cleared to zero, the shift-following performance is improved.

Next, the CVT-ECU 14 adjusts the clamping pressure of the belt 20 based on the inertia torque (step 135).
When the target rotational speed is switched, the gear ratio continuously changes, and as a result, the pulley rotational speed of the CVT input shaft 18 continuously increases and decreases. Due to this change in rotation, inertia torque is generated in the continuously variable transmission portion of the CVT, and as described above, when the pulley rotation speed of the input shaft 18 of the CVT 4 changes in the decreasing direction, the necessary clamping pressure cannot be secured. On the other hand, when the pulley rotation speed of the input shaft 18 of the CVT 4 changes in an increasing direction, an unnecessary load is applied to the belt, so that the CVT-ECU 14 performs the target rotation as shown in FIG. By calculating the inertia torque based on the amount of change of several Nintgt and changing the oil pressure PD by the calculated inertia torque, the necessary clamping pressure is ensured and unnecessary load is prevented.
The inertia torque is a torque that acts on the rotating body in an attempt to keep rotating due to the inertia (inertia) of the rotating body when the rotation of the rotating body is decelerated or stopped. When the inertia torque Tin, inertia (moment of inertia) Iin, and rotational speed Nin are used, the inertia torque Tin can be obtained by the following equation.
Tin = Iin * dNin / dt

  And even if the oil pressure setting by the inertia change is performed, such as when the line pressure PL of the oil pressure control device 9 is small or when the oil pressure cannot be increased to a predetermined value or more due to the balance with the clutch pressure, the oil pressure is set. If it cannot be raised, the necessary clamping pressure cannot be ensured and the belt may slip. However, since it is absolutely necessary to avoid the belt slipping, in such a case, CVT- The ECU 14 sets, as a threshold value, a predetermined value set from the clamp pressure command value of the secondary pulley 19 of the CVT 4 and the limit value of the line pressure predicted from the engine speed or the electric oil pump drive command value with respect to the shift speed, By slowing down the speed of the shift, the change of inertia torque is suppressed and the belt is prevented from slipping.

  On the other hand, if it is determined in step 131 that the engine is not stopped and the clutch is not released, the CVT-ECU 14 estimates the CVT 4 speed ratio control based on the normal speed ratio control, that is, the accelerator operation amount. A target gear ratio is set based on the required output calculated from the engine torque and the vehicle speed (step 136). Also in this case, when the target value is switched stepwise, the deviation at the time of switching increases, so that the CVT-ECU 14 has the target rotational speed so as to continuously switch at a predetermined inclination as shown in FIG. Set up.

  Next, the CVT-ECU 14 returns the feedback gain based on the feedback calculation formula to the normal setting, and limits the output value DUTY output to the shift control unit only during switching of the target rotational speed (step 137). Further, the CVT-ECU 14 clears the integral term of the calculation part of the feedback control (step 138) and improves the follow-up performance of the speed change as shown in FIG. At the same time, as shown in FIG. 12C, the clamping pressure of the belt 20 is adjusted based on the inertia torque (step 139) to secure the necessary clamping pressure on the belt and prevent unnecessary load from being applied.

Next, the CVT-ECU 14 calculates the target rotational speed Nintgt from the target speed ratio γtgt set in step 132 or step 136. Nintgt = γtgt * Nout
(Step 140). As described above, when the control is performed at the target rotational speed Nintgt, this calculation is not necessary.
Then, the CVT-ECU 14 obtains a DUTY value by the feedback calculation equation (3) using the target rotational speed Nintgt (step 141), and then determines whether or not the DUTY value is greater than 0 (step 142). . When DUTY ≧ 0%, the CVT-ECU 14 outputs the DUTY value to the DUTY solenoid DS1 (step 143), and when DUTY <0%, the DUTY value is output to the DUTY solenoid DS2 (step 143), and the program ends. To do.

  Note that if a downshift is applied before starting the engine and engaging the clutch, the engine speed and CVT primary pulley speed will be greatly separated, and the clutch engagement response will be worsened. When the engine is started after the vehicle is stopped, the gear ratio is set so that the CVT primary pulley rotational speed is close to the engine idle rotational speed until the engine is started and the clutch is completely engaged. It is preferable to control.

  In the above embodiment, an example in which the continuously variable transmission control device of the present invention is applied to a hybrid vehicle having an engine and a motor / generator has been described. However, the continuously variable transmission control device of the present invention is not a hybrid vehicle. It can also be used in the case where the eco-run area is expanded until the vehicle travels, such as when the engine is stopped in an accelerator-off deceleration state when applied to a power train eco-run system comprising an engine and CVT.

  In the above-described embodiment, a plurality of ECUs such as an HV-ECU and a CVT-ECU are used as the control device. However, the functions of the plurality of ECUs may be implemented by a single ECU. .

It is a figure which shows the whole system of the hybrid vehicle to which the continuously variable transmission control apparatus of this invention is applied. It is a figure which shows the structure of the hydraulic control part for controlling the continuously variable transmission part of CVT. It is a figure which shows the signal transmitted by multiplex communication between each ECU of a continuously variable transmission control apparatus. It is a figure which shows the state transition of the operation mode of an engine. It is a figure which shows the state transition of a clutch control mode. It is a table | surface which shows the transition conditions of each clutch control mode. It is a flowchart which shows the effect | action at the time of the change of an operation mode. It is a flowchart which shows the effect | action at the time of the change of an operation mode. It is a flowchart which shows the effect | action at the time of the change of an operation mode. It is a figure which shows the control chart of the clutch by EV driving mode transfer. It is a figure which shows the control chart of the clutch by regenerative driving mode transfer. It is a map which shows the target gear ratio of CVT at the time of an engine stop and clutch release. It is a figure which shows the rotation speed change at the time of target rotation speed switching of CVT, and the integral term of a feedback control circuit. It is a figure which shows the belt clamp pressure at the time of switching of the target rotational speed of CVT.

Explanation of symbols

1 Engine 2 Torque converter 3 Forward / reverse clutch 4 CVT
5 Gear 6 Front Drive Wheel 7 Motor / Generator 8 Rear Drive Wheel 9 Hydraulic Control Device 10 Mechanical Oil Pump 11 Electric Oil Pump 12 HV-ECU
13 ENG-ECU
14 CVT-ECU
15 MG-ECU
16 Inverter 17 Battery 18 Primary pulley 19 Secondary pulley 20 Belt DS1, DS2 DUTY solenoid V1, V2 Hydraulic valve

Claims (7)

The engine can be stopped even when the vehicle is traveling. When the engine is stopped while traveling, hydraulic oil is supplied to the pulley when shifting to the high gear ratio side, and A continuously variable transmission control device in a vehicle system that releases engagement means provided between a continuously variable transmission from which hydraulic oil is discharged when shifting to a speed ratio side and an engine, and
When the engine is stopped and the vehicle is in a stopped state, the gear ratio of the continuously variable transmission is controlled to a first gear ratio that is a high gear ratio, and when the engine is stopped and the vehicle is in a traveling state, Control means for controlling to a second speed ratio lower than the first speed ratio,
The second gear ratio in the control means is controlled so that the lower the gear ratio is, the higher the vehicle speed is, and the lower speed ratio is set wider than the high speed ratio. With
The control means reduces the responsiveness of the shift when controlling the speed ratio when the engine is stopped, compared to when controlling the speed ratio when the engine is driven. Step transmission control device. In the continuously variable transmission control device according to claim 1 ,
The continuously variable transmission control device according to claim 1, wherein the control means limits a shift amount that can be shifted within a predetermined time when the speed ratio is controlled when the engine is stopped. In the continuously variable transmission control device according to claim 1 ,
When the speed ratio is controlled when the engine is stopped, the control means changes the target value of the speed change control more smoothly than when the speed ratio is controlled when the engine is driven. A continuously variable transmission control device. In the continuously variable transmission control device according to claim 1 ,
The control means clears the integral term in the feedback control performed in the shift control when the shift control is switched between a state where the engine is driven and a state where the engine is stopped. apparatus. In the continuously variable transmission control device according to claim 1 ,
When the shift control is switched between a state where the engine is driven and a state where the engine is stopped, the control means determines the clamping force of the pulley of the continuously variable transmission according to the change speed of the speed ratio before and after the switch. A continuously variable transmission control device characterized by being changed. In the continuously variable transmission control device according to claim 5 ,
A continuously variable transmission control device, wherein a restriction is provided so that the clamping force of the pulley does not exceed a clamping force that can be realized by an oil pump that drives the pulley. In the continuously variable transmission control device according to claim 1 ,
When the engine is started after the engine is stopped and the vehicle is stopped, the control means controls the engine-side rotation speed of the continuously variable transmission until the engine starts and the engagement means completes engagement. A continuously variable transmission control device that controls a transmission gear ratio so that is close to an idle speed.