JP5873277B2 - Vehicle power transmission control device - Google Patents

Description

  The present invention relates to a vehicle power transmission control device.

  In recent years, a stepped transmission having a plurality of shift stages and not including a torque converter and a clutch torque (clutch transmitted) is interposed between an output shaft of an internal combustion engine and an input shaft of a stepped transmission. And a control means for controlling the clutch torque and the speed of the stepped transmission using the clutch actuator and the speed change actuator according to the running state of the vehicle. Control devices have been developed (see, for example, Patent Document 1). Such a power transmission control device is also called an automated manual transmission (AMT).

  In a vehicle equipped with an AMT, when a gear shifting operation (an operation for changing the gear position of the transmission) is performed, the clutch is operated from the engaged state (clutch torque> 0) by the clutch actuator before the gear shifting operation is started (clutch torque> 0). Clutch torque = 0), the shift operation is performed by the operation of the shift actuator while the clutch is maintained in the disconnected state, and the clutch is changed from the disconnected state to the connected state by the operation of the clutch actuator after the end of the shift operation. Returned.

JP 2006-97740 A

  In a vehicle equipped with an AMT, usually, a shift speed (required shift speed) to be selected from among the plurality of shift speeds is determined based on a running state of the vehicle (particularly, a vehicle speed and an accelerator opening), and a stepped speed change is performed. The speed of the machine is controlled so as to be the current required speed. In addition, if the difference in the number of steps when the required shift speed changes is 2 or more, the gear position of the stepped transmission is normally changed from the required shift speed before the change to the required shift speed after the change once. Is done. Hereinafter, this operation is referred to as “skip shift”. Typically, the skip shift is executed when the gear position is changed to the low speed side (so-called kick down) based on the rapid increase in the accelerator opening (skip down shift).

  By the way, at the time of kickdown, the amount of increase in the drive torque of the drive wheels is larger when the skip downshift is performed than when the gear position is changed to the low speed side by one. Therefore, if a skip downshift is performed in a state where slippage is likely to occur on the drive wheels, such as when the vehicle is traveling on a road surface with a low road surface friction coefficient (low μ road surface), due to a sudden increase in drive torque of the drive wheels, The running state of the vehicle tends to become unstable.

  In order to cope with this problem, it is conceivable to prohibit the kick-down itself in a state where the drive wheel is likely to slip. However, in this case, it is not possible to meet the driver's request that the driver wants to obtain a larger driving torque (and hence a larger acceleration) by shifting the gear position to the low speed side.

  An object of the present invention is a vehicle power transmission control device applied to a vehicle equipped with an AMT, and in the case where kickdown is performed in a state in which slipping is likely to occur on a drive wheel, while suppressing slipping of the wheel. An object of the present invention is to provide a driving wheel capable of increasing the driving torque of the driving wheel.

  The vehicle power transmission control device according to the present invention includes the stepped transmission (T / M), the clutch (C / T), and the control means (ECU, ACT1, ACT2) and the same type as described above. This is a power transmission control device.

  In a state where slip of a vehicle wheel (especially a drive wheel) is not detected, the control means performs a skip shift (especially a skip down) when the difference in the number of steps when the required shift speed changes is 2 or more. Shift) is executed.

In a state where slippage of the wheels (particularly driving wheels) is detected , the control means does not perform a skip shift and does not perform a skip shift when the difference in the number of steps when the required shift speed changes is two or more. a plurality of times toward the required speed after the change the gear position of the variable transmission from the required speed before the change is configured to gradually change one by one stage.
The power transmission control device is characterized in that the control means is configured not to execute the skip shift for a predetermined period from a time point when the wheel slip is detected once. .

  According to this, since the driving torque of the driving wheel increases stepwise in a plurality of times, the time when the driving wheel slips can be delayed as compared with the case where the skip downshift is performed ( (See FIG. 5 described later). In other words, wheel slip can be suppressed. In addition, since the driving torque of the driving wheels increases, it is possible to meet the driver's request that “I want to obtain a higher driving torque (and hence a higher acceleration) by shifting the gear position to the low speed side”. .

1 is a schematic configuration diagram of a vehicle equipped with a vehicle power transmission control device according to an embodiment of the present invention. 3 is a graph showing a map defining “stroke-torque characteristics” for the clutch shown in FIG. 1. 3 is a graph showing a map that defines the relationship between “vehicle speed and accelerator opening” and “gear to be selected” for the transmission shown in FIG. 1. It is the flowchart which showed the outline | summary of the control of the gear stage performed by embodiment of this invention. FIG. 5 is a time chart showing an example of an operation in the case where a shift of a gear is changed to a low speed side in order of a plurality of steps in place of a skip shift in a state where a wheel slip is detected.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a vehicle power transmission control device according to the present invention will be described with reference to the drawings.

(Constitution)
FIG. 1 shows a schematic configuration of a vehicle equipped with a power transmission control device (hereinafter referred to as “the present device”) according to an embodiment of the present invention. This vehicle includes a so-called automated manual transmission (AMT) that includes an internal combustion engine as a power source and uses a stepped transmission that does not include a torque converter and a clutch.

  This vehicle includes an engine E / G, a transmission T / M, and a clutch C / T. E / G is one of well-known internal combustion engines, for example, a gasoline engine that uses gasoline as fuel and a diesel engine that uses light oil as fuel. The E / G output shaft A1 is connected to the T / M input shaft A2 via C / T.

  The transmission T / M is one of well-known stepped transmissions that do not include a torque converter having a plurality of (for example, six) forward gears, one reverse gear, and a neutral gear. . The T / M output shaft A3 is connected to the drive wheels of the vehicle via a propeller shaft (not shown), a differential (not shown), and the like. The switching of the T / M shift speed is executed by controlling the transmission actuator ACT2. By changing the gear position, the reduction ratio (ratio of the rotational speed Ni of the input shaft A2 to the rotational speed No of the output shaft A3) is changed.

  The clutch C / T has one of well-known configurations, and the maximum torque (clutch torque Tc) that can be transmitted between the output shaft A1 of the E / G and the input shaft A2 of the T / M. It is configured to be adjustable. Specifically, the clutch C / T is a friction clutch disk having one of well-known configurations provided to rotate integrally with the input shaft A2 of the transmission T / M. The clutch disks are coaxially arranged so as to face each other with respect to a flywheel provided to rotate integrally with the output shaft A1 of the engine E / G. The axial position of the clutch disc relative to the flywheel can be adjusted. The axial position of the clutch C / T (specifically, the clutch disk) is adjusted by the clutch actuator ACT1. That is, this vehicle is not provided with a clutch pedal.

  Hereinafter, the axial movement amount of the clutch C / T (clutch disk) from the “original position” in the joining direction (crimping direction) is referred to as a clutch stroke. The “original position” is, for example, a reference position within the movable range in the axial direction of the clutch disk, or an end position (position where the stopper contacts the stopper) on the side far from the flywheel in the movable range. When the clutch C / T is in the “original position”, the clutch stroke is “0”.

  As shown in FIG. 2, the clutch torque Tc is adjusted by adjusting the clutch stroke. In the state of “Tc = 0”, no power is transmitted between the output shaft A1 of the engine E / G and the input shaft A2 of the transmission T / M. This state is referred to as “divided state”. Further, in the state of “Tc> 0”, power is transmitted between the output shaft A1 and the input shaft A2. This state is called a “joined state”.

  Further, a state where the clutch C / T is not slipped in the connected state (a state where the rotational speed Ne of the output shaft A1 and the rotational speed Ni of the input shaft A2 coincide) is particularly referred to as a “completely connected state”. A state where slippage occurs in the clutch C / T (a state where Ne and Ni do not match) is particularly called a “half-joined state”.

  In addition, this device detects the presence / absence of an operation of an accelerator opening sensor S1 that detects an operation amount (accelerator opening) of an accelerator pedal AP, a shift position sensor S2 that detects a position of a shift lever SF, and a brake pedal BP. Brake sensor S3, rotation speed sensor S4 that detects the rotation speed Ne of the output shaft A1, rotation speed sensor S5 that detects the rotation speed Ni of the input shaft A2, clutch stroke sensor S6 that detects the clutch stroke, and wheels And a wheel speed sensor S7 for detecting the rotational speed of the motor.

  Furthermore, this apparatus includes an electronic control unit ECU. The ECU controls the actuators ACT1 and ACT2 based on the information from the above-described sensors S1 to S7 and other sensors, etc., so that the C / T clutch stroke (accordingly, the clutch torque Tc), and , T / M shift speed is controlled. The ECU also controls the drive torque of the output shaft A1 of the E / G by controlling the fuel injection amount of the E / G (the opening of the throttle valve). Specifically, the fuel injection amount (throttle valve opening) is controlled so that the E / G drive torque increases as the accelerator opening increases.

  This device stores a shift map as shown in FIG. 3 in a ROM (not shown) in the ECU. FIG. 3 shows an example of the case where 1st to 6th speeds are provided as forward shift speeds. In the present apparatus, the gear position of the transmission T / M is determined based on the shift map. More specifically, in this apparatus, when the position of the shift lever SF is at a position corresponding to the “automatic mode”, the vehicle speed calculated based on the wheel speed obtained from the wheel speed sensor S7 and the accelerator opening sensor One shift speed to be selected (hereinafter referred to as “required shift speed”) is selected depending on which shift speed area on the shift map the combination with the accelerator opening obtained from S1 corresponds to. The For example, when the current vehicle speed is α and the current accelerator opening is β (see the black dot shown in FIG. 3), “3rd speed” is selected as the required shift speed.

  Such a shift map can be created by repeatedly performing an experiment in which the optimum shift stage is adapted to the combination of the vehicle speed and the accelerator opening while changing the combination in various ways. On the other hand, when the position of the shift lever SF is at a position corresponding to the “manual mode”, the required shift speed is selected based on the operation of the shift lever SF by the driver.

  The transmission T / M realizes (establishes) the current required shift speed among a plurality of shift speeds. When the vehicle travels in a state where the shift speed is established (fixed) to the required shift speed, the clutch C / T is normally maintained in a fully engaged state.

  On the other hand, when the required shift speed is changed while the vehicle is running, the shift operation of the transmission T / M (operation when the shift speed is changed) is performed. The start of the shift operation corresponds to the start of movement of a member (specifically, a sleeve) that moves in association with the change of the gear position, and the end of the shift operation corresponds to the end of movement of the member. When the shift operation is performed, the clutch C / T is changed from the engaged state (completely connected state, Tc> 0) to the disconnected state (Tc = 0) before the shift operation is started, and the clutch is maintained in the disconnected state. The shift operation is performed in the state, and the clutch is returned from the disconnected state to the engaged state (completely connected state) after the end of the shift operation. As described above, this vehicle is a vehicle equipped with an AMT.

(Shift speed control)
Next, shift speed control will be described with reference to the flowchart shown in FIG. In step 405, it is determined whether or not slipping of wheels (particularly, driving wheels) has been detected. The “slip” can be detected using a known method based on the detection result of the wheel speed sensor S7 of each wheel. Specifically, “slip” can be detected when the difference between the vehicle body speed and the wheel speed calculated based on the detection result of the wheel speed sensor S7 of each wheel is equal to or greater than a predetermined minute value.

  If no slip of the wheel (especially the drive wheel) has been detected (“No” in step 405), normal control is executed in step 410. In normal control, when the required shift speed is changed and the difference in the number of gears is 2 or more, the T / M shift speed is changed from “required shift speed before change” to “required shift speed after change” once. Will be changed. That is, skip shift is executed. Typically, a skip downshift is executed when the required shift stage moves two or more steps to the low speed side based on the rapid increase in the accelerator opening.

  On the other hand, when a slip of a wheel (particularly, a driving wheel) is detected (“Yes” in step 405), special control is executed in step 415. In the special control, if the difference in the number of steps when the required shift speed is changed is 2 or more, the skip shift is not executed, and the T / M shift speed is changed from “the required shift speed before change” to “after the change. It is changed in order one step at a time in multiple steps toward the “required gear”.

  Hereinafter, the operation and effect of this special control will be described with reference to the time chart shown in FIG. In the example shown in FIG. 5, the driving torque of the drive wheels temporarily exceeded the slip limit due to a temporary sudden increase / decrease in the accelerator opening immediately after time t1 while the vehicle was traveling at “5-speed”. Due to this, slip is detected in the drive wheels.

  In the example shown in FIG. 5, at time t2 after time t1, the required shift speed is moved from “5th speed” to “2nd speed” due to a stepwise increase in the accelerator opening (kick down). ). At this time, when the normal control is executed, a skip downshift from “5th speed” to “2nd speed” is executed as indicated by a broken line. In this case, since the amount of increase in driving torque by skip downshift is large, the driving torque of the driving wheels exceeds the slip limit immediately after time t2. Accordingly, the slip amount of the drive wheel changes with a large value immediately after time t2 (see the area indicated by the fine dots). As a result, the vehicle acceleration decreases immediately after time t2 due to the slip of the drive wheels.

  On the other hand, in the present apparatus, the special control is executed. That is, as indicated by the solid line, after the time t2, the gear position is changed to the low speed side in order of three steps from “5th speed” to “2nd speed”. In this case, since the amount of increase in the driving torque of the driving wheel is small compared to when the skip shift is executed, the driving torque of the driving wheel does not exceed the slip limit immediately after time t2. In other words, the time when the drive torque of the drive wheel exceeds the slip limit is delayed as compared with the case where the skip shift is executed. That is, it is possible to delay the timing at which the drive wheel slip occurs (see the shaded area). As a result, the vehicle acceleration can increase in accordance with the increase of the drive torque during the period until the slip occurs on the drive wheels.

  As described above, according to the present apparatus, when kickdown is performed in a state in which slipping is likely to occur on the drive wheel, special control is executed instead of normal control, thereby suppressing wheel slip. It is possible to increase the driving torque of the driving wheels (thus increasing the vehicle acceleration).

  In the example shown in FIG. 5, when the gear position is changed from “5th speed” to “2nd speed” in three times in order from the “5th speed” to the “low speed side”, the time during which each speed stage is maintained is equal. Alternatively, the time during which each gear position is maintained may be gradually shortened. Further, in the example shown in FIG. 5, the skip (down) shift is not performed over a predetermined time period T <b> 1 (see FIG. 5) from the time t <b> 1 when the wheel slip is once detected. May be configured.

  The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention. For example, in the above embodiment, a power transmission control device including a transmission including one input shaft and one clutch connected to the one input shaft is applied. A power transmission control device including a transmission including an input shaft and two clutches connected to each of the two input shafts may be applied. This device is also called a double clutch transmission (DCT).

  T / M ... transmission, E / G ... engine, C / T ... clutch, A1 ... engine output shaft, A2 ... transmission input shaft, A3 ... transmission output shaft, ACT1 ... clutch actuator, ACT2 ... speed change Actuator, ECU ... Electronic control unit

Claims (2)

It is a ratio of the rotational speed of the input shaft to the rotational speed of the output shaft, comprising an input shaft for inputting power from the output shaft of the internal combustion engine of the vehicle and an output shaft for outputting power to the drive wheels of the vehicle. A stepped transmission having a plurality of predetermined speeds with different reduction ratios;
A clutch interposed between an output shaft of the internal combustion engine and an input shaft of the stepped transmission and capable of adjusting a clutch torque that is a maximum value of torque that can be transmitted by the clutch;
Control means for controlling the clutch torque of the clutch and the gear position of the stepped transmission based on the running state of the vehicle ;
Comprising a detection means for detecting a slip of the wheel before Symbol vehicle, and
The control means includes
Based on the running state of the vehicle, a required shift speed that is a shift speed to be selected from among the plurality of shift speeds is determined, and the shift speed of the stepped transmission is controlled to be the current required shift speed. Configured to
The control means includes
In a state where the slip of the wheel is not detected, when the difference in the number of steps when the required shift speed is changed is 2 or more, the shift speed of the stepped transmission is changed from the required shift speed before the change. Is configured to perform a skip shift that changes to the required shift speed at a time,
In the state in which the slip of the wheel is detected, if the difference in the number of steps when the required shift speed is changed is 2 or more, the skip shift is not performed and the shift speed of the stepped transmission is changed before the change. In the power transmission control device for a vehicle, configured to sequentially change one step at a time in a plurality of times from the required gear to the changed required gear .
The control means includes
A vehicle power transmission control device configured not to execute the skip shift for a predetermined period from a point in time when the slip of the wheel is detected once. The power transmission control device for a vehicle according to claim 1,
The control means includes
When the gear stage of the stepped transmission is changed one by one in multiple steps from the requested gear stage before the change to the requested gear stage after the change, the time during which each gear stage is maintained A vehicle power transmission control device configured to be gradually shortened.

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