JP2006266315A - Start friction element controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a deterioration of a clutch by starting with the acceleration corresponding to an acceleration operation by a driver in a control to fasten the start clutch for a vehicle start. <P>SOLUTION: An engine rotational number NE is increased at an instant t1 and after by increasing acceleration opening APO from 0% to K% by the driver. At an instant t2, when the engine rotational speed NE in increasing as shown in (1) reaches a threshold NTRIG (Yes in step S1), the start clutch 3 is advanced to the fastening direction (step S6), and a clutch output side rotational speed NC starts to increase from 0 at the instant t2 and after. The start clutch 3 is controlled to fasten so that real acceleration ACCREAL of a vehicle conforms to target acceleration ACCTAR (steps S3 and S55), and so that the engine rotational speed NE falls between a lowr limit NHOLDMIN (steps S4 and S5) and an upper limit (steps S7 and S8). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control that realizes vehicle start by completely engaging a clutch that connects and disconnects an engine side and a drive wheel side when starting the vehicle while slip-engaging for starting.

Engagement control that provides a starting friction element such as a clutch on the drive transmission path from the engine to the drive wheel, and advances the released starting friction element from the slip state to complete engagement based on the accelerator operation by the driver when the vehicle starts. Conventionally, for example, the invention described in Patent Document 1 is known.
The starting clutch control device described in Patent Document 1 automatically performs a cooperative operation of a clutch and an accelerator, which has been performed by a driver so far, when a vehicle starts with a clutch engaged. . That is, in the engagement control of the starting clutch, while maintaining the engine speed Ne not to be smaller than the threshold value Nth, the engagement target speed Ntgt based on the throttle opening operated by the driver and the engine speed Ne A difference Ngap is calculated, a clutch pressure command value Tc is obtained from the difference Ngap, the estimated traveling load, and the estimated engine torque, and power transmission control for increasing or decreasing the clutch pressure is performed.

In addition, although it is not a clutch fastening control for starting, conventional clutch fastening control for temporarily releasing the clutch at the time of shift (shift) operation of the automatic transmission and re-engaging the clutch when the shift operation is completed is conventionally, for example, The thing as described in patent document 2 is known.
The clutch automatic control vehicle described in Patent Document 2 obtains a rotational speed difference between an engine rotational speed and a transmission rotational speed, obtains an allowable range of a target acceleration at the time of a shift operation from the rotational speed difference and an accelerator opening, Control is performed to engage the clutch so that the vehicle acceleration during shifting is within this allowable range.
Japanese Patent Laid-Open No. 2002-21888 Japanese Patent Laid-Open No. 11-247895

  However, the conventional clutch control causes problems as described below. That is, in the starting clutch control device described in Patent Document 1, the clutch torque increment is calculated from the rotational speed difference between the engagement target rotational speed determined by the throttle opening and the actual engine rotational speed, and the travel load estimated from the vehicle speed is calculated. Accordingly, since power transmission control is performed to increase the clutch torque increment in response to this, only control for compensating for the difference in rotational speed while matching the vehicle speed can be performed, and clutch control that starts at an acceleration according to the driver's accelerator pedal operation I can't do it.

  Then, it seems that by adopting the automatic clutch control described in Patent Document 2, it is possible to perform the power transmission control of the clutch so as to realize the target acceleration based on the driver's accelerator operation.

  However, the automatic clutch control during shifting described in Patent Document 2 cannot be simply applied to the clutch control during starting.

The reason is that the calculated target acceleration is not always appropriate, and if it is too large than the realizable acceleration obtained from road surface gradient, engine output or clutch engagement control, it is too large than the upper limit of the target acceleration allowable range. It becomes. At this time, since the vehicle acceleration at the start is smaller than the lower limit value of the target acceleration, the clutch is advanced in the engagement direction so as to be within these upper limit value and lower limit value.
As described above, in the automatic clutch control described in Patent Document 2 in which only the acceleration error is considered and the engine torque state is not considered, the engine is subjected to an excessive load by moving the clutch in the engagement direction. As a result, the engine speed decreases and the engine torque decreases, and the target acceleration cannot be achieved.

  In addition, if the calculated target acceleration is too smaller than the acceleration necessary and sufficient for driving, the target acceleration can be sufficiently achieved, but only the error of the acceleration is seen and the engine torque state is not considered In the automatic clutch control described in Document 2, the surplus obtained by subtracting the torque required for running from the engine torque increases the engine speed, leading to an increase in the differential rotation of the clutch and shortening the life of the clutch. Resulting in.

  An object of the present invention is to propose an automatic control device for a starting clutch that realizes acceleration according to an accelerator operation by a driver when the vehicle starts, and does not impair the durability of the clutch.

For this purpose, the control device for the starting friction element according to the invention is as claimed in claim 1,
When starting a vehicle, assuming a starting friction element control device that controls the fastening force of a friction element provided on a drive transmission path between the prime mover and driving wheels of the vehicle for starting,
The control device comprises target acceleration calculation means for calculating the target acceleration of the vehicle based on the accelerator operation of the driver, and target range calculation means for calculating the target range of the engine speed based on the accelerator operation,
Control for fastening the starting friction element is performed so that the acceleration of the vehicle coincides with the target acceleration and the engine speed falls within the target range.

According to the control device of the present invention, the target acceleration of the vehicle is calculated based on the driver's accelerator operation, and the vehicle acceleration is matched with the target acceleration. Can be realized.
Further, the target range of the engine speed is calculated based on the accelerator operation, and the engine speed is kept within the target range, so that the engine torque is not insufficient at the time of start and the life of the clutch is not shortened. Responsiveness and durability can be improved.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
FIG. 1 is a system diagram showing the overall configuration of a drive system including a starting friction element and its control device according to an embodiment of the present invention.
The engine 1 is drivingly coupled to the transmission 2 via a starting clutch 3 corresponding to a starting friction element. The starting clutch 3 makes the clutch stroke amount, that is, the engagement force variable by the hydraulic pressure to the engagement side or the release side. This hydraulic pressure is controlled by the clutch hydraulic actuator 4. The clutch hydraulic actuator 4 increases or decreases the hydraulic pressure supplied to the starting clutch 3, so that any one of a fastening state in which the engine torque of the engine 1 is transmitted to the transmission 2 as it is, a released state in which it is not transmitted at all, and a slip state in between. Can be selected.
While the start clutch 3 is in the engaged state and the slip state, the engine torque of the engine 1 is transmitted to the drive wheels through the start clutch 3, the transmission 2, a propeller shaft, a differential gear, and a drive shaft (not shown) in sequence.

The controller 5 gives a throttle opening command to the throttle valve actuator 6 that opens and closes the throttle valve opening of the engine 1 according to the accelerator opening, and also gives a clutch duty command to the hydraulic actuator 4. Further, when the vehicle starts, the controller 5 controls the engagement of a starting clutch 3 to be described later, the throttle opening compensation command TVOADD for the throttle opening actuator 6 and the clutch duty command for the hydraulic actuator 4. give.
Therefore, the controller 5 includes a signal from a brake switch that detects whether or not a brake pedal (not shown) is depressed, and an accelerator opening from an accelerator opening sensor 8 that detects the amount of depression of the accelerator pedal 7 operated by the driver. From the APO, the engine speed NE from the engine speed sensor 9 that detects the engine 1 side speed of the starting clutch 3, and the clutch speed sensor 10 that detects the transmission 2 side (output side) speed of the starting clutch 3 Clutch rotational speed NC, vehicle road surface gradient information, vehicle load information, selected transmission gear ratio of transmission 2, and operating state of engine 1 (intake air amount, fuel injection amount, throttle opening TVO) are input. To do.

  In the present embodiment based on these input information, when the vehicle starts, the start clutch 3 is advanced in the engagement direction based on the target acceleration, or the engagement control for maintaining the slip state is performed. The target acceleration ACCTAR is calculated by executing the process indicated by the diagram.

In FIG. 2, the engine torque estimating unit 51 reads the intake air amount of the engine 1, the fuel injection amount, and the throttle opening TVO, and calculates the engine speed NE and the engine torque TE for each throttle opening TVO. The current engine torque is estimated with reference to a known full performance map representing the relationship.
The gradient correction unit 52 calculates a torque correction amount for correcting the engine torque according to the road surface gradient of the vehicle from the road surface gradient information, that is, the engine speed NE, the selected transmission ratio of the transmission 2, the vehicle weight, and the tire radius.
The subtraction unit 53 performs a subtraction process for subtracting the torque correction amount calculated by the gradient correction unit 52 from the estimated engine torque estimated by the engine torque estimation unit 51.

The load correction unit 54 calculates a torque correction amount for correcting the engine torque according to the vehicle load from the vehicle load information, that is, the oil pump discharge amount, the power consumption of the vehicle air conditioner, and the like.
The subtracting unit 55 performs a subtracting process for subtracting the torque correction amount calculated by the load correcting unit 54 from the engine torque subtracted by the engine subtracting unit 53.

The equivalent inertia calculation unit 56 calculates the equivalent inertia from the engine 1 to drive wheels (not shown) according to the selected gear ratio of the transmission 2.
The division unit 57 divides the engine torque subtracted by the subtraction unit 55 by the equivalent inertia calculated by the equivalent inertia calculation unit 56, and obtains an ideal acceleration that is a theoretically required value.

  In consideration of the response of the engine torque TE to the throttle opening command, etc., the target acceleration adjusting unit 58 is configured to obtain the ideal acceleration obtained by the dividing unit 57 in order to prevent the driver from feeling uncomfortable with the actual acceleration. The target acceleration ACCTAR is obtained by performing arithmetic processing using the following equation (1).

なお、図２に機能別ブロック線図で示す上記処理においては、推定したエンジン１のトルクを、登坂路の路面勾配に基づき補正し（勾配補正部52）、車載エアコン等の補機類の電力消費量に基づき補正し（負荷補正部54）、走行環境および運転状態を総合的に考慮して目標加速度ACCTARを算出するものである。しかし、上記処理において誤差なきとも限らないことから、本実施例ではエンジン回転数が後述する上限値より大きくなる場合の処理で、目標加速度ACCTARを実際の加速度値にシフトさせる制御を行う。 Equation (1) is a function F (s) of a second-order lag system. Here, ω is a value determined by the lowest order frequency of the drive system natural frequency. ω is determined by vehicle characteristics. ζ is a value that determines the time gradient of the target acceleration ACCTAR. By adjusting ζ according to the vehicle running specifications, it is possible to make the rising of the target acceleration ACCTAR abrupt or slow.

In the above-described processing shown by the functional block diagram in FIG. 2, the estimated torque of the engine 1 is corrected based on the road surface gradient of the uphill road (gradient correction unit 52), and the power of auxiliary equipment such as the on-vehicle air conditioner is corrected. The target acceleration ACCTAR is calculated by comprehensively taking into account the driving environment and the driving state by correcting based on the consumption (load correcting unit 54). However, since there is no limitation in the above processing, in this embodiment, control for shifting the target acceleration ACCTAR to the actual acceleration value is performed in the processing when the engine speed becomes larger than the upper limit value described later.

FIG. 3 is a flowchart showing a start clutch engagement control program in the present embodiment. FIG. 3 shows a main routine for vehicle starting fastening control for controlling the starting clutch 3 for starting the vehicle.
When the vehicle is stopped and the starting clutch 3 is disengaged, the driver selects the D range or the R range, the brake switch is in the off state, and the accelerator opening APO is greater than 0%, the controller 5 The fastening control for the vehicle start shown is performed.

First, in step S1, it is determined whether or not the engine speed NE is larger than a threshold value NTRIG stored in advance. NTRIG is the minimum engine speed required for starting. If the engine speed NE is less than or equal to the threshold value NTRIG (No), the engine speed NE is low and inconvenient for starting, so the engine speed NE is continuously monitored. When the engine speed NE is larger than the threshold value NTRIG (Yes), the process proceeds to step S2.
In step S2, the target acceleration ACCTAR calculated by the processing of FIG. 2 described above is read.
In the next step S3, the vehicle speed is obtained by multiplying the clutch rotational speed NC by the selected gear ratio of the transmission 2, a reduction gear ratio of a differential gear (not shown), etc., and the actual acceleration ACCREAL is calculated from the time change of the vehicle speed. Then, it is determined whether or not the calculated actual acceleration ACCREAL is smaller than the target acceleration ACCTAR. When it is determined that the actual acceleration ACCRAL is smaller than the target acceleration ACCTAR (Yes), the process proceeds to step S4, and it is determined whether or not the engine speed NE is smaller than the lower limit value NHOLDMIN.

The lower limit value NHOLDMIN in step S4 is obtained from the range of the area stored in advance in the controller 5. The lower limit value NHOLDMIN is set larger as the throttle opening TVO increases.
The region here refers to region (1) or (2) in the overall engine performance map shown in FIG. Region (1) represents a region where the variation in engine torque is small relative to the variation in engine speed due to the characteristics of engine 1, as can be seen from the entire performance map. By selecting the lower limit value NHOLDMIN within the range (1), even if the engine speed NE is near the lower limit value NHOLDMIN, it is possible to prevent a sudden drop in engine torque, and clutch engagement control. Thus, smooth vehicle start can be realized.
On the other hand, the region (2) represents an engine speed region where the engine torque is maximum due to the characteristics of the engine 1 as can be seen from the entire performance map. By selecting the lower limit value NHOLDMIN within the range (2), a large engine torque can be obtained even when the engine speed NE is near the lower limit value NHOLDMIN, and the vehicle start performance is improved. be able to.
Whether to use region (1) or (2) depends on the design specifications.
Of course, the lower limit value NHOLDMIN is larger than the threshold value NTRIG described above. Further, the throttle opening TVO shown in FIG. 6 is proportional to the accelerator opening APO operated by the driver.

If it is determined in step S4 that the engine speed NE is not smaller than the lower limit value NHOLDMIN (No), the process proceeds to step S6.
In step S6, the clutch duty is increased to increase the fastening force of the starting clutch 3. The reason is that it is determined in step S3 that the actual acceleration is insufficient with respect to the target acceleration. Then, the process returns to step S2. This is for continuing the engagement control of the starting clutch 3.

  On the other hand, if it is determined in step S4 that the engine speed NE is smaller than the lower limit value NHOLDMIN (Yes), the process proceeds to step S5. This is to prevent the engine speed NE from dropping.

FIG. 4 is a flowchart showing the process control when the engine speed NE is smaller than the lower limit value NHOLDMIN in the starting clutch control of this embodiment. FIG. 4 shows a subroutine executed in step S5, which is mainly intended to compensate for an increase in the throttle opening TVO.
In FIG. 4, in step S51, the clutch duty is held in order to maintain the fastening force of the starting clutch 3. Here, the reason why the clutch duty is not increased is to prevent the adverse effect that the engine speed is further lowered by advancing the clutch 3 in the engagement direction in a state where the engine speed NE is smaller than the lower limit value NHOLDMIN. .

  In the next step S52, the throttle opening TVO is compensated. Therefore, the throttle opening compensation amount TVOADD is calculated, and the throttle opening compensation amount TVOADD is added to the current throttle opening TVO to obtain the compensated throttle opening TVO. The calculation of the throttle opening compensation amount TVOADD is obtained by storing the characteristic diagram shown in FIG. 7 in advance and referring to this characteristic diagram. The characteristic diagram shown in FIG. 7 shows the relationship between the rate of decrease in engine speed per unit time and the throttle opening compensation amount TVOADD. As the engine speed NE drops more rapidly, the throttle compensation amount TVOADD is increased.

In step S53, it is determined whether or not engine speed NE has reached or exceeded lower limit value NHOLDMIN. If it is not greater than or equal to the lower limit value NHOLDMIN (No), the process returns to step S51, and steps S51 to S52 are repeated until the engine speed NE becomes equal to or greater than the lower limit value NHOLDMIN. On the other hand, if the lower limit value NHOLDMIN is exceeded (Yes),
Proceed to step S54.

  In step S54, the clutch duty is increased to increase the fastening force of the starting clutch 3.

In the next step S55, it is determined whether or not the actual acceleration is greater than or equal to the target acceleration ACCTAR. When the actual acceleration is not equal to or higher than the target acceleration ACCTAR (No), the process returns to step S54, and the above steps S54 to S55 are repeatedly executed.
On the other hand, if the actual acceleration is greater than or equal to the target acceleration ACCTAR (Yes), the process proceeds to step S56. In step S56, the throttle opening compensation amount TVOADD is reset to 0, the subroutine control is exited, and the process returns to step S2 of the main routine.

  Returning to the main routine of FIG. 3, if it is determined in step S3 that the actual acceleration is not smaller than the target acceleration ACCTAR (No), the process proceeds to step S7, where the engine speed NE is greater than the upper limit value NHOLDMAX. Determine whether or not.

The upper limit value NHOLDMAX in step S7 is obtained from the range of the area stored in advance in the controller 5. As the throttle opening TVO increases, the upper limit value NHOLDMAX is set larger.
The region here refers to region (1) or (2) in the overall engine performance map shown in FIG. Region (1) represents a region where the variation in engine torque is small relative to the variation in engine speed due to the characteristics of engine 1, as can be seen from the entire performance map. By selecting the upper limit value NHOLDMAX within the range (1), even if the engine speed NE is close to the upper limit value NHOLDMAX, it is possible to prevent a sudden drop in engine torque and clutch engagement control. Thus, smooth vehicle start can be realized.
On the other hand, the region (2) represents an engine speed region where the engine torque is maximum due to the characteristics of the engine 1 as can be seen from the entire performance map. By selecting the upper limit value NHOLDMAX within the range (2), a large engine torque can be obtained even when the engine speed NE is near the upper limit value NHOLDMAX, and the vehicle start performance is improved. be able to.
Whether to use region (1) or (2) depends on the design specifications.
Of course, the upper limit value NHOLDMAX is larger than the lower limit value NHOLDMIN described above. Further, the throttle opening TVO shown in FIG. 6 is proportional to the accelerator opening APO operated by the driver.

If it is determined in step S7 that the engine speed NE is not greater than the upper limit value NHOLDMAX (No), the process proceeds to step S9.
In step S9, the clutch duty is maintained to maintain the fastening force of the starting clutch 3. This is because it is determined in step S3 that the actual acceleration is not insufficient with respect to the target acceleration, and the engine speed NE is below the upper limit value NHOLDMAX. Then, the process proceeds to step S10.

  On the other hand, if it is determined in step S7 that the engine speed NE is greater than the upper limit value NHOLDMAX (Yes), the process proceeds to step S8.

  FIG. 5 is a flowchart showing the processing control when the engine speed NE is larger than the upper limit value NHOLDMAX in the starting clutch control of this embodiment. FIG. 5 shows a subroutine executed in step S8, and the main purpose is to perform control for changing the target acceleration ACCTAR.

In FIG. 5, in step S81, the clutch duty is increased to increase the fastening force of the starting clutch 3. Thereby, the torque transmitted from the engine 1 to the transmission 2 via the starting clutch 3 increases.
Here, for example, referring to a characteristic diagram as shown in FIG. 8, the difference ΔN between the engine speed NE and the upper limit value NHOLDMAX is calculated, and the increase amount of the clutch duty increases as the difference ΔN increases.

In the next step S82, it is determined whether or not the engine speed NE has become equal to or lower than the upper limit value NHOLDMAX. If it is not less than or equal to the upper limit value NHOLDMAX (No), the process returns to step S81, and the above steps S81 to S82 are repeatedly executed until the engine speed NE becomes less than or equal to the upper limit value NHOLDMAX. On the other hand, if the upper limit value NHOLDMAX or less (Yes),
Proceed to step S83.

  In step S83, the actual acceleration ACCRAR is substituted into the target acceleration ACCTAR, and the target acceleration ACCTAR used so far is shifted to the actual acceleration ACCRAL. Then, the subroutine control is exited and the process returns to step S2 of the main routine.

The description returns to the main routine of FIG.
In step S10, it is determined whether or not the engine speed NE matches the clutch speed NC. If the engine speed NE does not match the clutch speed NCLT (No), the process returns to step S2 and the above control is repeated. On the other hand, when the engine rotational speed NE becomes the clutch rotational speed NC (Yes), this main routine is ended and the engagement control of the starting clutch 3 for starting the vehicle is completed.

9 and 10 are time charts showing the operation of the vehicle starting fastening control of this embodiment.
FIG. 9 shows the process control when entering the subroutine of step S5, and FIG. 10 shows the process control when entering the subroutine of step S8.
If the driver fully returns the brake pedal (not shown) at the instant t1, and the driver depresses the accelerator pedal 7 to increase the accelerator opening APO from 0% to K%, the engine speed NE increases after the instant t1. To do.

  At the subsequent instant t2, as shown in (1), when the increasing engine speed NE reaches the threshold value NTRIG (Yes in step S1), the engaging force of the starting clutch 3 is increased (step S6). The vehicle start fastening control is started. After the instant t2, the clutch output side rotational speed NC starts increasing from zero.

  The operation of the process when the engine speed NE is smaller than the lower limit value NHOLDMIN will be described.

When the actual acceleration indicated by the broken line is smaller than the target acceleration ACCTAR indicated by the solid line as shown in (2) at the instant t4 in FIG. 9 due to variations in estimation accuracy of the estimated torque shown in FIG. If the engine speed NE falls below the lower limit value NHOLDMIN as shown in (3) after the instant t4 in FIG. 9 (Yes in step S4), the clutch duty is held (step S51). Therefore, the clutch engagement capacity of the starting clutch 3 becomes constant after the instant t4 as shown in (4). Then, as shown in (5), a throttle opening compensation amount TVOADD is given (step S52).
When the engine speed NE recovers to the lower limit value NHOLDMIN as indicated by (6) at the instant t5 in FIG. 9 (Yes in step S53), the engaging force of the starting clutch 3 is increased after the instant t5 (step S54). The actual acceleration ACCREAL indicated by the broken line starts increasing as indicated by (7). At the following instant t6, when the actual acceleration ACCRAL becomes equal to or higher than the target acceleration ACCTAR indicated by the solid line as shown in (8) (Yes in step S55), the throttle opening compensation is ended as shown in (9) (step S56). The clutch duty is continuously increased after the instant t6 (step S6). Note that the clutch duty remains constant slightly after the instant t6 (step S9).
At the following instant t8, as shown in (10), when the clutch rotational speed NC matches the engine rotational speed NE (step S10), the vehicle start fastening control of this embodiment is terminated.
Therefore, even if the estimation accuracy of the estimated torque shown in FIG. 2 is reduced or a disturbance that cannot be corrected by the correction units 52 and 54 shown in FIG. 2 is applied, the actual acceleration ACCREAL can be matched with the target acceleration ACCTAR. it can.

  The operation of the process when the engine speed NE is larger than the upper limit value NHOLDMAX will be described.

If the engine speed NE exceeds the upper limit value NHOLDMAX (Yes in step S7) as shown in (3) at the instant t3 in FIG. 10 due to variations in estimation accuracy of the estimated torque shown in FIG. Is increased (step S81). Therefore, the clutch engagement capacity of the starting clutch 3 continues to increase after the instant t3 as shown in (4). Then, the actual acceleration ACCREAL indicated by the broken line in (5) exceeds the target acceleration ACCTAR indicated by the solid line.
When the engine speed NE decreases to the upper limit value NHOLDMAX as shown in (6) at the instant t9 in FIG. 10 (Yes in step S82), the clutch engagement capacity is also shown in (4) according to the characteristic diagram shown in FIG. The decrease starts between the instant t3 and the instant t9. At the instant t9, as shown in (7), the target acceleration ACCTAR is shifted to the actual acceleration ACCRAL and changed (step S83).
At the following instant t8, as shown in (8), when the clutch rotational speed NC matches the engine rotational speed NE (step S10), the vehicle start fastening control of this embodiment is finished.
Accordingly, the estimated degree of the estimated torque shown in FIG. 2 is reduced, or a disturbance that cannot be corrected by the correction units 52 and 54 shown in FIG. 2 is applied, so that the target acceleration ACCTAR is calculated to be lower than the actual situation and the engine speed is reduced. Even if the value exceeds the upper limit value NHOLDMAX, the actual acceleration ACCREAL can be matched with the target acceleration ACCTAR (instant t9).

As described above, in this embodiment, the start clutch 3 provided on the drive transmission path between the engine 1 and the drive wheels (not shown) is controlled to be engaged for the start of the vehicle.
In this fastening control, the controller 5 calculates the target acceleration ACCTAR of the vehicle based on the accelerator opening APO operated by the driver as shown in FIG. Further, the controller 5 calculates a lower limit value NHOLDMIN and an upper limit value NHOLDMAX, which are target ranges of the engine speed NE, based on the throttle opening degree TVO (accelerator opening degree APO) as shown in FIG.
Then, the clutch duty of the starting clutch 3 is controlled so that the actual acceleration ACCREAL of the vehicle matches the calculated target acceleration ACCTAR and the engine speed NE falls between the lower limit value NHOLDMIN and the upper limit value NHOLDMAX.
In this way, the engine speed NE is kept between the lower limit value NHOLDMIN and the upper limit value NHOLDMAX, so that the actual acceleration ACCREAL can be made to follow the target acceleration ACCTAR well, based on the driver's accelerator operation. The starting feeling can be realized at a high level.
In addition, the engine speed NE is kept between the lower limit value NHOLDMIN and the upper limit value NHOLDMAX, so the engine torque is not insufficient at the time of starting and the life of the clutch is not shortened. Can be improved.

  Here, the lower limit value NHOLDMIN and the upper limit value NHOLDMAX are selected from the range of the region (1) in which the fluctuation of the engine torque TE is small relative to the fluctuation of the engine speed NE on the entire performance map of the engine 1 shown in FIG. Thus, even if the engine speed NE temporarily deviates from between the lower limit value NHOLDMIN and the upper limit value NHOLDMAX, it is possible to prevent a sudden drop or increase in engine torque. Therefore, the vehicle start clutch fastening control is facilitated and a smooth vehicle start can be realized.

  Alternatively, by selecting the lower limit value NHOLDMIN and the upper limit value NHOLDMAX from the range of the region (2) where the engine torque TE is maximum on the entire performance map of the engine 1 shown in FIG. 6, the engine speed NE becomes the lower limit value NHOLDMIN. A large engine torque can be obtained even if it temporarily falls between the upper limit value NHOLDMAX and the upper limit value NHOLDMAX. Therefore, the starting performance of the vehicle can be improved.

  In order to control the clutch duty of the starting clutch 3 so that the engine speed NE falls between the lower limit value NHOLDMIN and the upper limit value NHOLDMAX, specifically, when the engine speed NE falls below the lower limit value NHOLDMIN, With reference to the characteristic diagram shown in FIG. 7 stored in advance, the throttle opening TVO of the engine 1 is compensated based on the time decrease rate −ΔNE / Δt of the engine speed NE that has been lowered. As a result, the engine speed NE can be recovered to the lower limit value NHOLDMIN. Therefore, the target acceleration ACCTAR can be achieved while preventing the engine torque from decreasing.

  Alternatively, when the engine speed NE exceeds the upper limit value NHOLDMAX, the clutch duty is increased in the above step S81, and in the subsequent step S82, it is determined whether the engine speed NE has fallen within the upper limit value NHOLDMAX. The target acceleration ACCTAR is changed to the actual acceleration ACCRIAL with the value recovered below the upper limit. Thus, the target acceleration ACCTAR obtained by the calculation of FIG. 2 described above does not necessarily have an error, and even when the target acceleration ACCTAR deviates from the actual situation and is smaller than the acceleration necessary and sufficient for traveling, FIG. As shown in (7), it becomes possible to match the practical acceleration necessary and sufficient for running. Therefore, it is possible to reduce the engine speed NE from being increased (blank) and to avoid the deterioration of the start clutch 3 due to the increase in the differential rotation of the start clutch 3.

1 is a system diagram illustrating an overall configuration of a drive system including a starting friction element and a control device thereof according to an embodiment of the present invention. In the same Example, it is a block diagram according to function which shows the process which calculates target acceleration ACCTAR. It is a flowchart which shows the control program of start clutch fastening of the Example. 5 is a flowchart showing process control when an engine speed NE is smaller than a lower limit value NHOLDMIN in the control program. 4 is a flowchart showing process control when an engine speed NE is larger than an upper limit value NHOLDMAX in the control program. FIG. 5 is a characteristic diagram referred to in order to obtain a lower limit value NHOLDMIN and an upper limit value NHOLDMAX corresponding to the throttle opening degree TVO (accelerator opening degree APO) in the control program. FIG. 5 is a diagram referred to in order to obtain a throttle opening compensation amount TVOADD corresponding to a time decrease rate “−ΔNE / Δt” of a lower engine speed NE in the control program. FIG. 7 is a diagram referred to in order to obtain a clutch duty command corresponding to a difference “ΔN” between an engine speed NE that has been exceeded and an upper limit value NHOLDMAX in the control program. It is a time chart which shows the effect | action of the vehicle starting clutch fastening control of the Example, Comprising: The case where an engine speed falls below lower limit NHOLDMIN is shown. It is a time chart which shows the effect | action of the vehicle starting clutch fastening control of the Example, Comprising: The case where an engine speed exceeds the upper limit NHOLDMAX is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Transmission 3 Start clutch 4 Clutch hydraulic actuator 5 Controller 6 Throttle valve actuator 7 Accelerator pedal 8 Accelerator opening sensor 9 Engine speed sensor
10 Clutch speed sensor

Claims (5)

In a starting friction element control device for performing control for fastening a friction element provided on a drive transmission path between a prime mover and a driving wheel of the vehicle at the time of starting,
The control device comprises target acceleration calculation means for calculating the target acceleration of the vehicle based on the accelerator operation of the driver, and target range calculation means for calculating the target range of the engine speed based on the accelerator operation,
An apparatus for controlling a starting friction element, wherein the starting friction element is controlled so that an acceleration of a vehicle coincides with the target acceleration and a motor rotational speed is within the target range.   2. The starting friction element control device according to claim 1, wherein the target range calculation means selects the target range from a rotational speed region in which the fluctuation of the motor torque is small relative to the fluctuation of the motor rotational speed. Control device for starting friction element.   2. The starting friction element control device according to claim 1, wherein the target range calculation means selects the target range from a rotation speed region where the motor torque is the largest. In the control apparatus of the starting friction element of any one of Claims 1-3,
When the motor speed falls below the target range, a starting friction is provided that compensates for the output of the motor based on the lower motor speed and keeps the motor speed within the target range. Element control unit. In the control apparatus of the starting friction element of any one of Claims 1-4,
When the prime mover rotational speed exceeds the target range, the starting friction element is operated in the direction of increasing the fastening force so that the prime mover rotational speed falls within the target range,
A control apparatus for a starting friction element, wherein a target acceleration is changed to an actual acceleration in a state where a motor rotational speed is within the target range.

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