JP5120241B2 - Creep traveling control device for vehicle and creep traveling control method for vehicle - Google Patents

Description

  The present invention relates to a technique for controlling creep travel of a vehicle by controlling engagement of a starting clutch provided between an engine and drive wheels.

2. Description of the Related Art Conventionally, a technique is known in which a road surface gradient is detected by a gradient detection sensor, and the engagement capacity of a starting clutch is controlled according to the detected gradient (see Patent Document 1).
JP 2006-17147 A

  However, the conventional technique has a problem that the cost is increased because the gradient detection sensor is expensive.

  A creep travel control device for a vehicle according to the present invention is a device for controlling creep travel of a vehicle having a starting clutch provided between an engine and a transmission, and a rotation direction detecting means for detecting the rotation direction of wheels. A rotational angular velocity detecting means for detecting the rotational angular speed of the wheel; a rotational angular acceleration calculating means for calculating the rotational angular acceleration of the wheel based on the rotational direction and the rotational angular speed; and a fastening capacity of the starting clutch based on the rotational angular acceleration. A clutch engagement capacity calculation means for calculating the engagement time, a clutch engagement time calculation means for calculating an engagement time from the start to the completion of engagement of the starting clutch based on the rotational angular acceleration, and a clutch engagement capacity and a clutch engagement time. And clutch engagement control means for controlling the engagement of the starting clutch.

  A creep driving control method for a vehicle according to the present invention is a method for controlling creep driving of a vehicle having a start clutch provided between an engine and a transmission, which detects the rotational direction of a wheel and detects the rotational angular velocity of the wheel. Is detected, the rotational angular acceleration of the wheel is calculated based on the rotational direction and rotational angular velocity, the starting clutch engagement capacity is calculated based on the rotational angular acceleration, and the starting clutch is engaged based on the rotational angular acceleration. The engagement time from the start to the completion is calculated, and the engagement of the starting clutch is controlled based on the clutch engagement capacity and the clutch engagement time.

  According to the present invention, the engagement of the start clutch can be controlled in accordance with the road surface gradient without using a sensor for detecting the road surface gradient.

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

  FIG. 1 is a block diagram illustrating a configuration of a vehicle creep travel control apparatus according to an embodiment. The driving force of the engine 1 is transmitted to the transmission 4 via the first clutch C1 or the second clutch C2. The driving force changed by the transmission 4 is transmitted to the left and right drive wheels 8a and 8b via the speed reducer 5 and the axles 7a and 7b. The transmission 4 including the clutches C1 and C2 is also called a dual clutch type (twin clutch type) automatic manual transmission.

  The first clutch C1 is for odd gears (first speed, third speed, fifth speed, reverse speed), and the second clutch C2 is for even gear speeds (second speed, fourth speed, sixth speed). When an odd gear is selected as the transmission gear, the first clutch C1 is engaged, and when an even gear is selected, the second clutch C2 is engaged. In this dual clutch type automatic manual transmission, for example, when a shift command from an odd gear to an even gear is issued during traveling in an odd gear selection state in which the first clutch C1 is engaged, the next selection is made. Shifting from the odd gear to the even gear is performed by changing the clutch in which the gear selection of the even gear is preceded and the first clutch C1 is released and the second clutch C2 is engaged.

  The rotation sensor 6 detects the rotation direction and rotation angular velocity of the axle 7a that transmits the driving force to the wheels 8a via the speed reducer 5. Since the axle shaft 7a and the wheel 8a rotate integrally, it can be said that the rotation sensor 6 detects the rotation direction and the rotation angular velocity of the wheel 7a. The rotation sensor 6 detects the rotational angular velocity in the forward direction of the vehicle as a positive value, and detects the rotational angular velocity in the backward direction of the vehicle as a negative value. The detected signal is output to the controller 10.

  The controller 10 performs control of the engine 1, engagement control of the clutches C <b> 1 and C <b> 2, and control of the transmission 4. In particular, the controller 10 controls the engine 1, the clutches C <b> 1 and C <b> 2, and the transmission 4 in order to perform so-called creep travel from a state where the vehicle is stopped.

  FIG. 2 is a flowchart showing the content of creep travel control performed by the controller 10. With the vehicle stopped, the controller 10 starts the process of step S10.

  In step S10, it is determined whether or not the absolute value of the rotational angular velocity ω detected by the rotation sensor 6 is greater than 0, that is, whether or not the vehicle has started to move from a stopped state. If it is determined that the absolute value of the rotational angular velocity ω is 0, the process of the flowchart is terminated, and if it is determined that the absolute value is greater than 0, the process proceeds to step S20.

  In step S20, it is determined whether or not the absolute value of the rotational angular velocity ω detected by the rotation sensor 6 is equal to or greater than a predetermined clutch engagement determination angular velocity W. The predetermined clutch engagement determination angular velocity W is a threshold value for determining whether or not the clutches C1 and C2 are to be engaged based on the magnitude of the rotational angular velocity ω, and an appropriate value is set in advance through experiments or the like. Keep it. If it is determined that the absolute value of the rotational angular velocity ω is less than the predetermined clutch engagement determination angular velocity W, the process returns to step S10. If it is determined that the absolute value of the rotation angular speed ω is greater than or equal to the predetermined clutch engagement determination angular speed W, the process proceeds to step S30.

  In step S30, the rotational angular acceleration α is calculated from the following equation (1) based on the rotational angular velocity ω detected by the rotation sensor 6.

  α = Δω / Δt (1)

  For example, when the time when the absolute value of the rotational angular velocity ω starts to be greater than 0 is t0 and the time when the absolute value of the rotational angular velocity ω is equal to or greater than a predetermined clutch engagement determination angular velocity W is t1, the rotational angular velocity at time t1. Using ω, ω / (t1−t0) can be calculated as the rotational angular acceleration α.

  In step S40, it is determined whether or not the calculated rotational angular acceleration α is greater than zero. If it is determined that the rotational angular acceleration α is greater than 0, the process proceeds to step S50. Steps S50 to S70 are, for example, processing performed in a situation where the vehicle is stopped on the downhill and the vehicle starts to move forward when the driver releases the brake.

  In step S50, the clutch to be engaged is determined based on the rotational angular acceleration α.

  FIG. 3 is a diagram showing the relationship between the rotational angular acceleration α and the clutch to be selected. As shown in FIG. 3, when the rotational angular acceleration α is equal to or less than the predetermined acceleration α1, the first clutch C1 is selected. When the rotational angular acceleration α is larger than the predetermined acceleration α1, the second clutch C2 is selected. select. This is because the first clutch C1 is engaged during the normal start when the rotational angular acceleration α is equal to or less than the predetermined acceleration α1, and the first speed gear is selected as the transmission gear of the transmission 4, and the rotational angular acceleration α is predetermined. If the acceleration is greater than α1, the second clutch C2 is engaged and the second gear is selected. That is, the case where the rotational angular acceleration α is larger than the predetermined acceleration α1 is, for example, a case where the slope of the downhill is large, so that when the first gear is connected, the shock at the time of connection becomes large. Therefore, a second gear having a smaller gear ratio than that of the first gear is connected to reduce a shock at the time of connection.

  In step S60, the clutch engagement capacity determined in step S50 is calculated based on the rotational angular acceleration α. FIG. 4 is a diagram showing the relationship between the rotational angular acceleration α and the clutch engagement capacity. As shown in FIG. 4, the clutch engagement capacity is reduced as the rotational angular acceleration α increases. That is, the greater the downhill gradient, the more the vehicle moves without the need for creep torque, so the clutch engagement capacity is reduced and the creep torque is reduced. The controller 10 holds data that defines the relationship between the rotational angular acceleration α and the clutch engagement capacity as shown in FIG. 4 and refers to the data based on the rotational angular acceleration α calculated in step S30. Thus, the clutch engagement capacity is calculated.

  In step S70, a clutch engagement time required from the start of clutch engagement to the completion of clutch engagement is determined based on the rotational angular acceleration α. FIG. 5 is a diagram showing the relationship between the rotational angular acceleration α and the clutch engagement time. As shown in FIG. 5, the clutch engagement time is shortened as the rotational angular acceleration α increases. That is, the greater the downhill gradient, the more the vehicle moves without the need for creep torque, so the creep torque is increased over time. The controller 10 holds data that defines the relationship between the rotational angular acceleration α and the clutch engagement time as shown in FIG. 5, and refers to the data based on the rotational angular acceleration α calculated in step S30. Thus, the clutch engagement time is calculated.

  The controller 10 issues a command to engage the clutch determined in step S50 based on the clutch engagement capacity calculated in step S60 and the clutch engagement time calculated in step S70. Based on this command, the engagement of the clutch determined in step S50 is controlled.

  If it is determined in step S40 that the rotational angular acceleration α is 0 or less, the process proceeds to step S80. Steps S80 to S110 are, for example, processing performed in a situation where the vehicle is stopped on the uphill and the vehicle starts to move backward when the driver releases the brake. In this case, the first clutch C1 is selected as the clutch that is engaged for creep running.

  In step S80, the engagement capacity of the first clutch C1 is calculated based on the absolute value of the rotational angular acceleration α. FIG. 6 is a diagram showing the relationship between the rotational angular acceleration α and the clutch engagement capacity. As shown in FIG. 6, as the absolute value | α | of the rotational angular acceleration α increases, the clutch engagement capacity increases. That is, as the slope of the uphill is larger, the creep torque is increased and the rollback of the vehicle is suppressed. The controller 10 holds data defining the relationship between the rotational angular acceleration α and the clutch engagement capacity as shown in FIG. 6, and the above data is based on the absolute value of the rotational angular acceleration α calculated in step S30. The clutch engagement capacity is calculated by referring to FIG.

  In step S90, the necessary engine torque is calculated based on the clutch engagement capacity calculated in step S80. FIG. 7 is a diagram showing the relationship between the clutch engagement capacity and the required engine torque. As shown in FIG. 7, the required engine torque increases as the clutch engagement capacity increases. The controller 10 has data that defines the relationship between the clutch engagement capacity and the engine torque as shown in FIG. 7, and by referring to the data based on the clutch engagement capacity calculated in step S80, Calculate the required engine torque.

  As described above, the clutch engagement capacity is calculated based on the absolute value of the rotational angular acceleration α. Accordingly, by preparing in advance data defining the relationship between the absolute value of the rotational angular acceleration α and the required engine torque, referring to the above data based on the absolute value of the rotational angular acceleration α calculated in step S30. The required engine torque may be calculated. In this case, the required engine torque increases as the absolute value of the rotational angular acceleration α increases.

  In step S100, the current engine torque is subtracted from the required engine torque calculated in step S90 to obtain the torque increase amount ΔT_eng of the engine torque. The current engine torque is the engine torque in the idling state.

  In step S110, the clutch engagement time is determined based on the absolute value of the rotational angular acceleration α. FIG. 8 is a diagram showing the relationship between the absolute value | α | of the rotational angular acceleration α and the clutch engagement time. As shown in FIG. 8, the clutch engagement time is shortened as the absolute value of the rotational angular acceleration α increases. That is, the greater the slope of the uphill, the faster the clutch engagement is completed and the vehicle rollback is effectively suppressed. The controller 10 has data that defines the relationship between the absolute value of the rotational angular acceleration α and the clutch engagement time, as shown in FIG. 8, and is based on the absolute value of the rotational angular acceleration α calculated in step S30. The clutch engagement time is calculated by referring to the data.

  The controller 10 issues a command for increasing the engine torque to the engine 1 based on the torque increase amount ΔT_eng of the engine torque obtained in step S100. Based on this command, the engine 1 increases the output engine torque. Further, after issuing the engine torque increase command, the controller 10 issues a command for engaging the first clutch C1 based on the clutch engagement capacity calculated in step S80 and the clutch engagement time calculated in step S110. put out. Based on this command, the engagement of the first clutch C1 is controlled.

  FIG. 9 illustrates the engagement capacity of the first clutch C1, the engine torque command that is engaged based on the command from the controller 10, and the actual torque that is transmitted to the transmission 4 when the processing from step S80 to step S110 is performed. It is a figure which shows the time change of an engine torque, respectively. As described above, the engine torque command value increases based on the torque increase amount ΔT_eng. Further, the engagement capacity of the first clutch C1 gradually increases and becomes the clutch engagement capacity obtained in step S80 after the clutch engagement time obtained in step S110. As the clutch engagement capacity increases, the actual engine torque transmitted to the transmission 4 also increases.

  According to the vehicle creep travel control device in one embodiment, the device is a device for controlling the creep travel of a vehicle including start clutches C1 and C2 provided between the engine 1 and the transmission 4, and the rotation of the wheels. The direction and rotational angular velocity are detected, and the rotational angular acceleration of the wheel is calculated based on the detected rotational direction and rotational angular velocity. Based on the calculated rotational angular acceleration, the engagement capacity and engagement time of the start clutches C1, C2 are calculated, and the engagement of the start clutches C1, C2 is controlled based on the clutch engagement capacity and the clutch engagement time. Accordingly, the start-up clutches C1 and C2 can be engaged and creep travel can be controlled according to the road surface gradient without providing a dedicated sensor for detecting the road surface gradient. Also, when the brake switch is turned off (brake force is 0) from a state where the vehicle has stopped on a hill, the conventional technology for starting the engagement of the starting clutch weakens the braking force even if the vehicle starts to move. Engagement of the start clutch is not started unless the switch is turned off. However, according to the vehicle creep travel control device in one embodiment, engagement of the start clutch can be started according to the vehicle behavior.

  Further, since the engine torque at the time of detecting the reverse of the vehicle is increased more than the engine torque at the time of detecting the forward movement of the vehicle, it is possible to suppress the rollback in which the vehicle moves backward when starting uphill. Furthermore, the engine torque increases as the absolute value of the rotational angular acceleration at the time of vehicle reverse detection increases. For example, as the slope of the uphill increases, the creep torque is increased and the rollback is more effectively suppressed. can do.

  According to the vehicle creep travel control device in one embodiment, the starting clutch is the first clutch C1 that is engaged when the odd-numbered gear stage of the transmission 4 is selected, and the second clutch that is engaged when the even-numbered gear stage is selected. When the rotational direction is the forward direction of the vehicle, it is determined which of the first clutch C1 and the second clutch C2 is to be engaged based on the rotational angular acceleration. In particular, when the rotational angular acceleration is equal to or less than a predetermined angular acceleration, the first clutch C1 is determined as an engagement clutch, and when the rotational angular acceleration is greater than the predetermined angular acceleration, the second clutch C2 is determined as an engagement clutch. As a result, for example, when the slope of the downhill is large, the second speed gear is connected via the second clutch C2, and the creep travel is performed. Shock can be reduced.

  The present invention is not limited to the embodiment described above. For example, although it has been described that the first clutch C1 and the second clutch C2 are provided as the starting clutch, only one starting clutch may be provided. In this case, the process of step S50 in the flowchart shown in FIG. 2 is omitted.

  Although the rotation direction and rotation angular velocity of the wheel are detected by one rotation sensor 6, a rotation direction detection sensor and a rotation angular velocity detection sensor may be provided.

It is a block diagram which shows the structure of the creep drive control apparatus for vehicles in one Embodiment. 4 is a flowchart showing processing contents performed by a controller 10. It is a figure which shows the relationship between the rotational angular acceleration at the time of a downhill start, and the clutch to select. It is a figure which shows the relationship between the rotation angular acceleration at the time of a downhill start, and clutch fastening capacity | capacitance. It is a figure which shows the relationship between the rotation angular acceleration at the time of a downhill start, and clutch fastening time. It is a figure which shows the relationship between the rotation angular acceleration at the time of uphill start, and a clutch fastening capacity | capacitance. It is a figure which shows the relationship between the clutch fastening capacity | capacitance at the time of uphill start, and required engine torque. It is a figure which shows the relationship between the rotation angular acceleration at the time of uphill start, and clutch fastening time. It is a figure which respectively shows the time change of the engagement capacity of the 1st clutch fastened based on the command from a controller at the time of uphill starting, an engine torque command, and the real engine torque transmitted to a transmission.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine 4 ... Transmission 6 ... Rotation sensor 8a, 8b ... Wheel C1, C2 ... Clutch 10 ... Controller

Claims (7)

A creep travel control device for a vehicle that controls creep travel of a vehicle by controlling engagement of a starting clutch provided between an engine and a transmission,
Rotation direction detection means for detecting the rotation direction of the wheel;
Rotation angular velocity detection means for detecting the rotation angular velocity of the wheel;
A rotational angular acceleration calculating means for calculating a rotational angular acceleration of a wheel based on the rotational direction and the rotational angular velocity;
Clutch engagement capacity calculating means for calculating an engagement capacity of the starting clutch based on the rotational angular acceleration;
Clutch engagement time calculation means for calculating an engagement time from the start of engagement of the starting clutch to completion based on the rotational angular acceleration;
Clutch engagement control means for controlling the engagement of the starting clutch based on the clutch engagement capacity and the clutch engagement time;
A creep travel control device for a vehicle, comprising: The creep travel control device for a vehicle according to claim 1,
The vehicle creep running further comprising engine torque control means for increasing the engine torque when the rotation direction is the reverse direction of the vehicle to be higher than the engine torque when the rotation direction is the forward direction of the vehicle. Control device. The creep travel control device for a vehicle according to claim 2,
The creep driving control device for a vehicle according to claim 1, wherein the engine torque control means increases the engine torque as the clutch engagement capacity increases. The creep travel control device for a vehicle according to claim 2,
The creep driving control device for a vehicle according to claim 1, wherein the engine torque control means increases the engine torque as the absolute value of the rotational angular acceleration increases. The creep travel control device for a vehicle according to any one of claims 1 to 4,
The starting clutch is composed of a first clutch that is engaged when the odd-numbered shift stage of the transmission is selected, and a second clutch that is engaged when the even-numbered speed stage is selected,
When the rotational direction is the forward direction of the vehicle, the clutch further includes an engagement clutch determining unit that determines which one of the first clutch and the second clutch is to be engaged based on the rotational angular acceleration. A creep travel control device for a vehicle characterized by the above. The creep travel control device for a vehicle according to claim 5,
The engagement clutch determining means determines the first clutch as an engagement clutch when the rotational angular acceleration is equal to or less than a predetermined angular acceleration, and when the rotational angular acceleration is greater than the predetermined angular acceleration, A creep travel control device for a vehicle, wherein the clutch is determined as an engagement clutch. A vehicle creep travel control method for controlling creep travel of a vehicle including a start clutch provided between an engine and a transmission,
Detect the direction of wheel rotation,
Detect the rotational angular speed of the wheel,
Based on the rotational direction and the rotational angular velocity, calculate the rotational angular acceleration of the wheel,
Based on the rotational angular acceleration, calculate the engagement capacity of the starting clutch,
Based on the rotational angular acceleration, calculate the engagement time from the start of engagement of the start clutch until completion,
A creep travel control method for a vehicle, wherein the engagement of the start clutch is controlled based on the clutch engagement capacity and the clutch engagement time.

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