JP2012116412A - Control device for hybrid electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly suppress a slip by performing control according to each driving situation for the slip of a drive wheel that occurs under various driving situations, in a control device for a hybrid electric vehicle.SOLUTION: The control device for the hybrid electric vehicle includes: an engine 1 and a motor 3 as a travel drive source; a clutch 2 interposed between the engine 1 and the motor 3; a slip ratio calculation means 60b for calculating an actual slip ratio of the drive wheel 8; a target slip ratio setting means 60d for setting a target slip ratio of the drive wheel 8 based on an on-off state of the clutch 2 and a travel state of the vehicle if the slip of the drive wheel 8 is detected; and an output torque control means 60e for controlling output torque of the travel drive source so that the actual slip ratio will become the target slip ratio if the slip of the drive wheel 8 is detected.

Description

  The present invention relates to a control device for a hybrid electric vehicle.

For example, on a low μ road or the like, when starting or accelerating a vehicle, the drive wheel may idle depending on how the accelerator pedal is depressed or the road surface μ. For example, if one road surface of the left and right drive wheels is frozen and the road surface μ is extremely low, the one drive wheel may idle when the accelerator pedal is depressed.
When the drive wheels are idle, the startability and acceleration of the vehicle are deteriorated, and drivability is deteriorated. In the worst case, the drive wheels are stuck, which hinders the running of the vehicle.

Therefore, a technique called an anti-spin regulator (ASR) has been developed as a technique for suppressing the idling of the drive wheel. In this ASR, the idling of the drive wheel is suppressed by controlling the brake of the drive wheel and the torque of the engine (internal combustion engine).
On the other hand, in recent years, a parallel hybrid electric vehicle equipped with an engine and a motor generator (hereinafter also simply referred to as a motor) has been developed as a traveling drive source. The drive wheel may idle due to the road surface condition or the driver's accelerator operation, and it is desired to suppress such idling of the drive wheel.

  For example, Patent Document 1 includes an engine and a motor as drive sources. When starting, torque assist is performed by the motor with an instruction torque corresponding to the accelerator opening, and wheel slip is detected during the torque assist. In such a case, a technique has been proposed in which the assist torque of the motor is reduced compared to when no slip is detected. As a result, the assist torque instruction value in the case of performing torque assist by the motor at the start can be optimized, and both the response at the start and the stability of the vehicle behavior can be achieved.

JP 2008-68704 A

  By the way, in a parallel hybrid electric vehicle, there is a configuration in which the engine can be separated and traveled using only the motor as a drive source. In this configuration, as a mode of traveling using the motor, the torque of the engine is controlled by the torque of the motor. As in the case of assisting, there are a mode in which the engine and the motor are both driven as a drive source and a mode in which only the motor is used as a drive source. If control is added, it is considered that such slip suppression can be performed appropriately and promptly.

Driving wheel slips are likely to occur not only when the vehicle starts, but also when the vehicle accelerates. If slip suppression control appropriate for each of the start and acceleration is applied, such slip suppression can be appropriately performed. It can be done quickly.
In Patent Document 1, it is assumed that torque assist is performed by a motor at the time of starting, and consideration is given to a case where the vehicle runs using only the motor as a drive source, or a case where drive wheel slip occurs during acceleration of the vehicle. The above problem cannot be solved.

  The present invention has been devised in view of such a problem, and in a hybrid electric vehicle having an engine and a motor as drive sources, each driving situation is different from driving wheel slips that occur under various driving conditions. One object of the present invention is to provide a control apparatus for a hybrid electric vehicle that can appropriately suppress slip by performing the corresponding control.

  In order to achieve the above object, a control apparatus for a hybrid electric vehicle according to the present invention includes an engine and a motor as a travel drive source, and a clutch that is interposed between the engine and the motor and separates the engine from the drive system. And a control device for a hybrid electric vehicle comprising drive wheels to which output torque from the travel drive source is transmitted via a transmission, and a clutch state detecting means for detecting a connection / disconnection state of the clutch, Vehicle state determining means for determining whether the vehicle is running or accelerating; slip detection means for detecting slip of the drive wheel; and the driving wheel based on the vehicle body speed of the vehicle and the wheel speed of the driving wheel. Actual slip ratio or actual slip corresponding value (actual slip ratio or actual rotational speed difference between driven wheel and drive wheel) that is a parameter value corresponding to the actual slip ratio is calculated. When the slip detection value is detected by the slip detection means and the slip detection means, the clutch engagement / disengagement state detected by the clutch state detection means and the vehicle state determination means are determined. Based on the running state of the vehicle, set the slip ratio of the driving wheel or the target value of the slip corresponding value which is the parameter value corresponding to the slip ratio (target slip ratio or target rotational speed difference between the driven wheel and the driving wheel). When the slip of the driving wheel is detected by the target value setting means and the slip detection means, the actual slip correspondence value calculated by the slip correspondence value calculation means is the target value set by the target value setting means. Output torque control means for controlling the output torque of the travel drive source so as to perform target slip control. It is characterized in Rukoto.

The target value when the vehicle is in a starting state is preferably set to a lower slip side (a higher side if the slip rate) than the target value when the vehicle is in an acceleration state.
The target value is set as a target value band having a width, and the target value band when the clutch is in an engaged state is set to a band wider than the target value band when the clutch is in a disconnected state. It is preferable that

The output torque control means performs feedback control (for example, PID control) based on a difference between the actual slip correspondence value calculated by the slip correspondence value calculation means and the target value set by the target value setting means. It is preferable to control the output torque of the travel drive source.
Furthermore, the output torque control means has maintained the state of the slip corresponding to the actual slip of the drive wheel at a lower slip side (a higher side if the slip rate) than the preset reference slip correspondence value for a preset time or more. In this case, or in the case where the transmission is gear shift switching for releasing the power connection between the motor and the drive wheel, the target slip control is preferably terminated.

The end of the target slip control is preferably ramp control.
Clutch control means for controlling the clutch; and achievement determination means for determining whether or not the target slip control can be achieved with the maximum output torque of the motor, wherein the clutch control means includes the clutch state detection means. When it is detected that the clutch is in the engaged state, and the achievement determining means determines that the target slip control cannot be achieved with the maximum output torque of the motor, the clutch is switched to the disconnected state. Is preferred.

  According to the control apparatus for a hybrid electric vehicle of the present invention, when slip of the drive wheel is detected, the slip of the drive wheel is determined based on the clutch engagement / disengagement state and the vehicle running state (starting state or acceleration state). The target value of the slip corresponding value which is the ratio or the parameter value corresponding to the slip ratio (for example, the target slip ratio or the target rotational speed difference between the driven wheel and the drive wheel) is set, and the actual slip corresponding value is set to the target value. Since the output torque of the travel drive source (motor or engine) is controlled so as to be, the slip ratio of the drive wheels can be appropriately controlled.

  For example, by setting the target value when the vehicle is in a starting state to a lower slip side (the higher side if the slip rate) than the target value when the vehicle is in an accelerating state, the drive wheel slips reliably when starting. It is possible to start while suppressing, and by allowing slip to some extent at the time of acceleration during traveling, slip of the drive wheel can be suppressed while ensuring good traveling performance. In other words, when starting a vehicle, it is most important to suppress the slip of the drive wheels and reliably transmit the drive wheel torque to the road surface. Therefore, it is effective to set the target value to the low slip side (the higher the slip ratio). It is. On the other hand, since the tire has a characteristic of exhibiting the maximum frictional force when it is slipping moderately, the acceleration performance can be improved by allowing the drive wheels to slip to some extent. For this reason, it is effective to set the target value on the relatively high slip side (on the low side if the slip rate).

  By setting this target value as a wide target value band, it is possible to stabilize the control. In particular, when the clutch is in the engaged state (connected state), an engine with low follow-up to the control command is also controlled. Therefore, if the target value band when the clutch is in the engaged state is set to a relatively wide band, the control can be stabilized. On the other hand, when the clutch is in the disengaged state (disengaged state, disengaged state), only the motor with high follow-up to the control command is controlled, so control is possible even if the target value band when the clutch is in the engaged state is a relatively narrow band It is possible to control the slip state more appropriately while stabilizing.

Further, by using feedback control (for example, PID control) based on the difference between the actual slip correspondence value and the target value for the output torque control of the travel drive source, the output torque of the motor can be appropriately controlled.
Further, when the actual slip correspondence value is lower than the preset reference slip correspondence value and the state on the low slip side (the slip ratio is high) continues for a preset time or longer, the target slip control is unnecessary, In addition, when the transmission is gear shift switching for releasing the power connection between the motor and the drive wheel, the output torque control of the motor cannot be performed. Therefore, unnecessary control can be eliminated by terminating the target slip control. it can.

  In addition, because it is determined that the target slip control cannot be achieved with the maximum output torque of the motor because the clutch is in the connected state, the target slip control is achieved by switching the clutch to the disconnected state and eliminating the influence of the engine. It becomes possible.

1 is a configuration diagram of a power system of a hybrid electric vehicle and a control device thereof according to an embodiment of the present invention. It is a block diagram of a control device concerning one embodiment of the present invention. It is a graph explaining the characteristic of the slip ratio (slip correspondence value) concerning one Embodiment of this invention, and its target value. It is a flowchart explaining the control concerning one Embodiment of this invention, (a) is a flowchart regarding target slip ratio (target value of a slip corresponding value) setting, (b) is a flowchart regarding torque control of a motor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a power system and its control device of a hybrid electric vehicle according to this embodiment, FIG. 2 is a block diagram of this control device, and FIG. 3 explains the characteristics of the slip ratio and its target value for this control. FIG. 4 is a flowchart for explaining the control. This will be described with reference to these drawings.

[Configuration of power system]
First, a configuration of a power system of a hybrid electric vehicle to which the control device according to the present embodiment is applied will be described.
The hybrid electric vehicle according to the present embodiment is a commercial vehicle such as a truck or a bus, for example, and is a large vehicle or a medium-sized vehicle having a larger vehicle body than a passenger vehicle, and is equipped with a diesel engine.

  As shown in FIG. 1, a vehicle (here, a vehicle front portion) includes an engine (internal combustion engine) 1, a clutch unit 2, a motor (motor generator) 3 and a transmission (transmission) 4 as a drive system. Further, the transmission 4 is connected to the rear wheels 8 and 8 as drive wheels via a propeller shaft 5, a rear differential (rear differential) 6 and drive shafts 7 and 7 so as to be able to transmit power. The front wheels 9, 9 are driven wheels.

In the present embodiment, a so-called dual clutch transmission (hereinafter also referred to as DCT) is used for the transmission 4. In this DCT, the clutch and the transmission gear mechanism are divided into two systems of odd-numbered stages and even-numbered stages, and the gears can be shifted in a very short time (only the clutch switching time) by switching the two clutches. it can.
That is, in the clutch unit 2, the first clutch 2A and the second clutch 2B are arranged side by side on the same axis. The first clutch 2A and the second clutch 2B are connected and disconnected independently by a clutch actuator (not shown).

Further, the transmission 4 includes a first transmission gear mechanism 4A equipped with a gear pair of even speed stages of 2nd speed, 4th speed and 6th speed, and odd speed speeds of 1st speed, 3rd speed and 5th speed. And a second transmission gear mechanism 4B equipped with a pair of gears arranged side by side on the same axis.
The input sides of the first clutch 2A and the second clutch 2B are connected to the output shaft 1A of the engine 1, and the output side of the first clutch 2A is connected to the input shaft (first input shaft) 40A of the first transmission gear mechanism 4A. The output side of the second clutch 2B is connected to an input shaft (second input shaft) 40B of the second transmission gear mechanism 4B.

  The first input shaft 40A is a hollow shaft and is coaxially disposed on the outer periphery of the second input shaft 40B. The first input shaft 40A is rotatably equipped with a second speed drive gear 42a, a fourth speed drive gear 44a, and a sixth speed drive gear 46a, and a portion of the second input shaft 40B protruding from the end of the first input shaft 40A. The first-speed drive gear 41a, the third-speed drive gear 43a, and the fifth-speed drive gear 45a are rotatably mounted.

  The motor 3 is mounted on the outer periphery of the first input shaft 40A between the clutch unit 2 and the first and second transmission gear mechanisms 4A and 4B. That is, the rotor (rotor) 31A of the motor 3 is fixed to the outer periphery of the first input shaft 40A, and the stator (stator) 3B is supported on the outer periphery of the rotor 3A by a transmission casing (not shown). Is arranged opposite to the rotor 3A, receives power supply during power running to rotate the rotor 3A, generates power by rotation on the rotor 3A side during regeneration, and applies a braking force according to the power generation load to the rotor 3A side. Give.

  Further, a counter shaft 40C is disposed in parallel with the input shafts 40A and 40B, next to the first input shaft 40A and the second input shaft 40B. The counter shaft 40C is fixedly provided with a 2nd speed driven gear 42b, a 4th speed driven gear 44b, a 6th speed driven gear 46b, a 1st speed driven gear 41b, a 3rd speed driven gear 43b, and a 5th speed driven gear 45b, and meshes with the drive gears of the corresponding gears. is doing. The counter shaft 40C is connected to the propeller shaft 5 via a gear pair 48, and the counter shaft 40C is interlocked with the propeller shaft 5.

  As described above, each of the drive gears 41a to 46a is rotatably supported on the input shaft 40A or 40B. However, the drive gears 41a to 46a rotate integrally with the input shafts 40A and 40B through the synchronization devices 47a to 47d, respectively. It has become. The second-speed drive gear 42a will be described as an example. The synchronizer 47a includes a sleeve 47sl that rotates integrally with the input shaft 40A or 40B and is slidable in the axial direction, and an actuator (not shown) that slides the sleeve 47sl. And a clutch gear 47cg fixed to each drive gear. When the sleeve 47sl slides and engages with the clutch gear 47cg, the drive gear to which the engaged clutch gear 47cg is fixed corresponds to the corresponding input shaft. Rotates integrally with 40A or 40B.

  Therefore, for example, when achieving the second speed, if the corresponding sleeve 47sl is slid and engaged with the clutch gear 47cg of the second speed drive gear 42a, the second speed drive gear 42a rotates integrally with the input shaft 40A. At this time, if the first clutch 2A is connected, the engine 1, the first clutch 2A, the first input shaft 40A, the second speed drive gear 42a, the second speed driven gear 42b, the counter shaft 40C, the gear pair 48 , Propeller shaft 5, rear differential 6, drive shafts 7 and 7, and drive wheels 8 and 8 are formed, and the rotation of the engine 1 is changed at a gear ratio corresponding to the second gear to drive wheels 8 and 8. Is transmitted to.

Similarly, the fourth speed and the sixth speed can also be achieved by engaging the sleeve 47sl corresponding to each clutch gear 47cg and connecting the first clutch 2A.
Similarly, the first speed, the third speed, and the fourth speed can be achieved by engaging the sleeve 47sl corresponding to each clutch gear 47cg and connecting the second clutch 2B.
Therefore, for example, in order to shift up from the second speed to the third speed, the second sleeve is connected to the clutch gear 47cg of the second speed drive gear 42a and the corresponding clutch 47A is engaged and the first clutch 2A is connected. In the state where the second clutch 2B is disconnected, the corresponding clutch 47cg of the third speed drive gear 43a is engaged with the corresponding sleeve 47sl, and the second clutch 2B is connected while the first clutch 2A is disconnected. The so-called clutch change is performed. Since the clutch gear 47cg and the sleeve 47sl of the shift destination gear stage (in this case, the third speed stage) can be pre-engaged during the second speed travel, the speed change operation affecting the torque transmission is Only the clutch is changed, and a substantially quick shift (shifting of the gear stage) can be performed.

  As described above, when one of the first clutch 2A and the second clutch 2B is connected, the other is shut off. However, in the case of this drive system, the first input shaft 40A is equipped with the motor 3, Even if both the first clutch 2A and the second clutch 2B are disconnected, the power can be transmitted to the motor 3. Therefore, both the clutches 2A and 2B are disconnected and the motor 3 can be driven at a driving torque or engine brake. It is possible to realize regenerative braking main braking without using the.

  The operation of the motor 3 is controlled by the inverter 31. The inverter 31 supplies power to the motor 3 from a battery (for example, a battery group in which a plurality of chargeable / dischargeable secondary cells (cells) such as lithium ion batteries are connected in series) during powering and outputs the power. The motor 3 functions as a motor that generates torque, and at the time of regenerative braking, the motor 3 functions as a power generator that generates electric power (regenerative power generation) using the kinetic energy of the vehicle. Used for.

[Overall configuration of control system]
The above-described engine 1, clutch 2A, 2B, motor 3, battery 32 and inverter 31 are controlled or managed by electronic control using a computer.
An engine ECU 61 for controlling the engine 1, an inverter ECU 62 for controlling the inverter 31 for operating the motor 3, and a battery ECU 63 for managing the battery 32, respectively, are provided, and these engine ECU 61, inverter ECU 62, A vehicle ECU 60 is provided to control the battery ECU 63 and the clutch 2.

Each of these ECUs 60, 61, 62, 63 is a computer comprising a CPU, ROM, RAM, input / output circuit, etc., and appropriate devices are attached or connected thereto.
The vehicle ECU 60 determines the vehicle running state (for example, vehicle speed (body speed), acceleration), the slip state of the drive wheels 8, the state of driving or braking command to the vehicle (for example, accelerator operation amount or brake operation amount), The engine ECU 61, the inverter ECU 62, the battery ECU 63, and the clutches 2A and 2B are controlled based on the charge amount of the battery 32 (hereinafter, the value of the charge amount is indicated by “SOC”).

  The battery ECU 63 includes a battery current sensor 51 that detects a charge / discharge current of the battery 32, a battery voltage sensor 52 that detects a charge / discharge voltage of the battery 32, and a battery charge / discharge counter that detects the number of times of charge / discharge of the battery 32. 54, and the charge amount SOC of the battery 32 is calculated by the battery ECU 63 based on the current and voltage when the battery 32 is charged and discharged. Therefore, the battery ECU 63 corresponds to battery charge amount detection means.

  These sensors 51 and 52 and the counter 54 are connected to each cell of the battery 32, and may detect the current, voltage, and number of charge / discharge of each cell, or one sensor for several cells. May be connected to detect the current, voltage, and the number of charge / discharge of these several cells, or a combination of connecting one sensor to each of these cells or to some cells may be combined as appropriate. Each sensor may be provided.

Further, the inverter ECU 62 manages the transmission and reception of electric power of the motor 3 and the battery 32 connected to the inverter 31 by controlling the inverter 31. For example, power generated by regenerative power generation of the motor 3 is used for charging the battery 32 in the normal state, but can be supplied to other power consuming devices when the battery 32 cannot be charged.
When driving, the vehicle ECU 60 sets a driving torque necessary for the vehicle based on the accelerator operation amount, and sets which one of the engine 1 and the motor 3 is used, or both of them. When both the motor 3 and the motor 3 are used, the drive torque is distributed. The engine ECU 61 and the inverter ECU 62 control the operation of the engine 1 or the motor 3 so as to output the drive torque set by the vehicle ECU 60.

  For example, when the vehicle starts, the clutch 2 is basically disengaged and the driving torque of only the motor 3 is used, and during the subsequent driving, the engine 1 is started and the clutch 2 is connected, and the driving torque of the engine 1 is mainly used. In addition, the vehicle travels using the driving torque of the motor 3 as an auxiliary. However, when the amount of charge of the battery 32 is insufficient, or when the temperature of the battery 32 has risen to a predetermined temperature or more, the vehicle 3 travels using only the engine 1 without using the motor 3 when starting or traveling. To do.

Further, at the time of braking, basically, the clutch 2 is disengaged and the rotational energy of the drive wheels 8 is sent only to the motor 3 to perform regenerative power generation. The electric power generated by the regenerative power generation is normally used for charging the battery 32.
However, when the amount of charge SOC of the battery 32 has reached the upper limit or near the upper limit, or when the temperature of the battery 32 has risen to a predetermined temperature or higher, the electric power generated by regenerative power generation is used for charging the battery 32. It is not possible.

That is, deterioration of the battery 32 is promoted when the charge amount becomes excessively high. Moreover, even if the charge amount is excessively reduced, the deterioration is caused. Therefore, the vehicle ECU 60 also manages the charge amount of the battery 32.
In the case of this apparatus, the vehicle ECU 60 controls the slip state of the drive wheels 8 based on the connection / disconnection state of the clutches 2A and 2B and the traveling state of the vehicle, in addition to each control unique to the hybrid electric vehicle. The point is that slip control is performed. This slip control will be described below.

[Slip control]
First, in this slip control, a target value is set for a slip ratio (also referred to as a slip ratio) of the drive wheel 8 at the time of idling of the drive wheel 8 or a slip corresponding value that is a parameter value corresponding to the slip ratio. Control is performed so that the slip correspondence value (actual slip correspondence value) becomes this target value. Here, a case where the slip correspondence value is the slip ratio λ itself will be described. Therefore, here, the slip control is referred to as slip ratio control.

The slip ratio λ of the drive wheel 8 during idling is defined by the following equation (1) from the vehicle body speed V and the wheel speed V _dw of the drive wheel 8. Here, the vehicle body speed V is obtained from the wheel speed V _fw of the driven wheel (front wheel) 9.
λ = (V−V _dw ) / V _dw (1)

As the slip correspondence value, in addition to the slip ratio λ, as a parameter value corresponding to the slip ratio, for example, the rotational speed difference ΔV between the wheel speed V _dw of the drive wheel 8 and the wheel speed V _fw of the driven wheel (front wheel) 9 (= V _dw −V _fw ) may be used.

In order to control the slip ratio, the vehicle ECU 60 includes a vehicle state determination unit 60a that determines whether the vehicle is in a starting state or an acceleration state, a slip detection unit 60b that detects a slip of the drive wheels 8, and a vehicle body speed. Slip rate calculating means (slip-corresponding value calculating means) 60c for calculating the actual slip rate λ _r of the drive wheel 8 from V and the wheel speed V _{dw of} the drive wheel 8, and the slip of the drive wheel 8 when the drive wheel 8 slips Target slip ratio setting means (target value setting means) 60d for setting a target slip ratio λ _tb that is a target value of the ratio λ, and the motor 3 and the engine so that the slip ratio λ of the drive wheels 8 becomes the target slip ratio λ _tb. Output torque control means (motor control means and engine control means) 60e for controlling the output torque of 1 (including negative torque during regeneration, etc.) and target slip ratio control can be achieved The achievement determination means 60f for determining whether or not the clutch, the clutch control means 60g for controlling the clutches 2A and 2B, and the end determination means 60h for determining the end of the target slip ratio control are all functional elements by computer software. As prepared.

Further, the vehicle ECU 60 receives the wheel speed sensor 55 for detecting the wheel speed V _dw of the driving wheel 8 and the wheel speed V _fw of the driven wheel (front wheel) 9 corresponding to the vehicle body speed V for the slip ratio control. Respective detection signals are input from a wheel speed sensor 56 to be detected and a clutch switch (clutch state detection means) 57 for detecting the connection / disconnection state of the first and second clutches 2A and 2B. Yes. The means for detecting the connection / disconnection state of each clutch 2A, 2B may be a stroke sensor for detecting the stroke of the movable element of each clutch 2A, 2B.

The vehicle state determination means 60a determines the start of the vehicle and the acceleration during the travel from the vehicle body speed V. That is, if the increased state of the vehicle body speed V continues for a preset time or longer, it is determined that the vehicle is accelerating. At this time, the vehicle body speed V at the start of acceleration of the vehicle is set to a small threshold value (stop of the vehicle). if it is less than threshold value for determining) V ₀ to determine to determine the acceleration starting and, if the vehicle speed V is small threshold greater than or equal _to V _0, the acceleration in traveling this acceleration.

When the time change rate ΔV _dw of the wheel speed V _dw of the drive wheel 8 detected by the wheel speed sensor 55 exceeds the preset reference change rate ΔV _dw 1, the slip detection means 60 b generates a slip on the drive wheel 8. It is determined that That is, at the start of slipping due to idling of the drive wheels 8, the wheel speed V _dw of the drive wheels 8 increases rapidly, so that this is detected and the slip of the drive wheels 8 is determined. The reference change rate ΔV _dw 1 that is the determination threshold is set to a value larger than the maximum value of the time change rate (corresponding to the maximum acceleration of the vehicle) when the drive wheels 8 are gripping the road surface. If this slip determination is made, then it is determined that the drive wheel 8 is slipping until the slip ratio control is finished. For this slip determination, when the difference ΔV between the wheel speed V _dw of the drive wheel 8 and the wheel speed V _fw of the driven wheel (front wheel) 9 exceeds (V _dw −V _fw ) exceeds the reference difference ΔV1, the drive wheel It may be determined that a slip has occurred in FIG.

The slip ratio calculating means 60c calculates the actual slip ratio λ _r of the driving wheel 8 during idling from the vehicle body speed V and the wheel speed V _dw of the driving wheel 8 according to the above equation (1).
When the slip detection means 60b detects the slip of the drive wheel 8, the target slip ratio setting means 60d detects whether the clutches 2A and 2B are detected by the clutch switch 57 and the vehicle state determination means 60a. The target slip ratio λ _tb of the drive wheels 8 is set based on the traveling state of

This control device is characterized by the setting of the target slip ratio _λtb . As shown in FIG. 3, whether the clutches 2A and 2B are in a connected state or a disconnected state, and whether the vehicle is in a starting state or an accelerating state. Accordingly, four target slip ratios λ _tb are prepared. Further, the target slip ratio λ _tb is not set as one value but is set as a band having a width.
Thus, the reason why the target slip ratio λ _tb is set as a target value band having a width is that feedback control based on the slip ratio λ described later can be stabilized. However, depending on the control mode, the target slip ratio can be set as a point having no width.

A first target slip ratio band λ _tb 1 shown in FIG. 3 is a target slip ratio band λ at start when the clutches 2A and 2B are both disconnected and the output torque of the engine 1 is not involved in the running of the vehicle. _tb . At this time, the vehicle is driven by the output torque of the motor 3. In this case, as the shift stage of the transmission 4, any one of the shift stages of the first transmission gear mechanism 4A equipped with the motor 3 is used.

The second target slip ratio band λ _tb 2 shown in FIG. 3 is a target slip ratio band at the start when either of the clutches 2A and 2B is connected and the output torque of the engine 1 is involved in the running of the vehicle. λ _tb . At this time, if any one of the shift stages of the first transmission gear mechanism 4A equipped with the motor 3 is used, the vehicle can be driven by adding the output torque of the motor 3 to the output torque of the engine 1.

The third target slip ratio band λ _tb 3 shown in FIG. 3 is a target slip ratio band λ during acceleration when the clutches 2A and 2B are both disconnected and the output torque of the engine 1 is not involved in the running of the vehicle. _tb . At this time, the vehicle is driven by the output torque of the motor 3. In this case, any one of the shift stages of the first transmission gear mechanism 4A equipped with the motor 3 is used as the shift stage of the transmission 4.

A fourth target slip ratio band λ _tb 4 shown in FIG. 3 is a target slip ratio band at the start when either of the clutches 2A and 2B is connected and the output torque of the engine 1 is involved in the running of the vehicle. λ _tb . At this time, if any one of the shift stages of the first transmission gear mechanism 4A equipped with the motor 3 is used, the vehicle can be driven by adding the output torque of the motor 3 to the output torque of the engine 1.

As shown in FIG. 3, the first target slip ratio band λ _tb 1 and the second target slip ratio band λ _tb 2 that are the target slip ratio bands λ _tb at the start of the vehicle both have a large slip ratio λ. (i.e., the slip is small) is set in the area, while the third target slip rate band lambda _{tb 3} and the fourth target slip ratio band lambda _{tb 4} of a target slip rate band lambda _tb during acceleration of the vehicle, In either case, the slip ratio λ is set to a small region (that is, the slip is large).

This is because, when starting the vehicle, it is most important to start with the slip of the drive wheel 8 reliably suppressed. Therefore, the target slip ratio bands λ _tb 1 and λ _tb 2 at the start of the vehicle are both slip ratios. It is set in a region where λ (slip ratio) is large (that is, there is little slip).
On the other hand, since the tire of the drive wheel 8 exhibits the maximum frictional force when the vehicle is running, the acceleration performance is better when the slip of the drive wheel 8 is allowed to some extent. Can do. For this reason, the target slip ratio bands λ _tb 3 and λ _tb 4 at the time of acceleration of the vehicle are all set in a region where the slip ratio λ (slip ratio) is small (that is, the slip is large).

Further, when both the clutches 2A and 2B are disconnected and the output torque of the engine 1 is not involved in the running of the vehicle, and the vehicle is running only by the output torque of the motor 3, the vehicle is also started. Even during acceleration, the target slip ratio band λ _tb 1, λ _tb 3 is the target slip ratio band λ when either of the clutches 2A, 2B is connected and the output torque of the engine 1 is involved in the running of the vehicle. _The width is narrower than _tb 2 and λ _tb 4.

This is because when the vehicle is running only by the output torque of the motor 3, only the output torque of the motor 3 needs to be controlled in order to control the actual slip ratio λ _r within the target slip ratio band λ _tb . . Since the motor 3 has good responsiveness during torque control, it can be sufficiently controlled even if the target slip ratio band λ _tb is set narrow. Therefore, the target slip ratio bands λ _tb 1 and λ _tb 3 when the clutches 2A and 2B are both in the disconnected state have a relatively narrow target slip ratio band λ _tb so that the slip ratio λ becomes more appropriate. It is doing.

On the other hand, when the vehicle is running using the output torque of the engine 1, in order to control the actual slip ratio λ _r within the target slip ratio band λ _tb , the output torque of only the engine 1 is controlled, Alternatively, the output torque of both the engine 1 and the motor 3 is controlled, and in any case, the control of the output torque of the engine 1 is essential. In the case of the engine 1, since the response at the time of torque control is low, if the width of the target slip ratio band λ _tb is narrowed, the control cannot be stabilized. Therefore, in the target slip ratio bands λ _tb 2 and λ _tb 4 when either of the clutches 2A and 2B is in the connected state, the width of the target slip ratio band λ _tb is relatively wide in consideration of control stability. It is.

Output torque control unit 60e, at the time of the slip of the driving wheels 8, such that the actual slip ratio lambda _r calculated by the slip ratio calculating unit 60c becomes the target slip ratio setting unit 60d target slip ratio band lambda in _tb set by The output torque of the motor 3 and the engine 1 is controlled.
Here, when the actual slip ratio lambda _r is deviated from the target slip rate band lambda _tb, the actual slip ratio lambda _r and the deviation between the target slip rate band lambda _tb, that is, the actual slip ratio lambda _r is the target slip rate band lambda in _tb The output torque of the motor 3 and the engine 1 is controlled by feedback control based on the value Δλ necessary for entering.

If the actual slip rate λ _r is larger than the upper limit value λ _{tbmax of the} target slip rate band λ _tb (the boundary value on the left side of each band in FIG. 3) (the left side in FIG. 3), the deviation Δλ Thus, if the actual slip ratio λ _r is smaller than the lower limit value λ _tbmin (the boundary value on the right side of each band in FIG. 3) of the target slip ratio band λ _tb (right side in FIG. 3), Each shall be requested.
Δλ = λ _r −λ _tbmax (2)
Δλ = λ _r −λ _tbmin (3)

  Here, PID control is used for feedback control in this case, but the combination of P control, I control, and D control may be set as necessary.

FIG. 2 is a block diagram relating to the processes of the slip ratio calculating means 60c, the target slip ratio setting means 60d, and the output torque control means 60d. If the actual slip ratio λ _r deviates from the target slip ratio band λ _tb, Δλ Then, Δλ is processed by PID control to obtain an output torque correction amount ΔT, and the output torque correction amount ΔT (n) is added to the driver's required torque T _dr to obtain the current target output torque T _t (n ) Is output.

Incidentally, if the actual slip ratio lambda _r has not deviated from the target slip ratio band lambda _tb, the required torque T _dr driver, the output torque correction amount ΔT of when the actual slip ratio lambda _r enters the target slip ratio band lambda _tb (K) is added and the current target output torque T _t (n) is output. When actual slip ratio lambda _r is entered to the target slip rate band lambda _tb, since the set previous output torque correction amount [Delta] T (n-1) to the current output torque correction amount [Delta] T (n), the actual slip ratio lambda _r As long as the actual slip ratio λ _r does not _{exceed the} target slip ratio band λ _tb , the output torque correction amount ΔT (k) when the actual slip ratio λ _r enters the target slip ratio band λ _tb becomes the current output torque correction amount ΔT (n). Set.

The output torque control means 60e outputs a command signal to the inverter ECU 62 so that the target output torque T _t (n) is all achieved by the motor 3 when traveling using only the motor 3, and only the engine 1 is operated. If the travel is used, a command signal is output to the engine ECU 61 so that the target output torque T _t (n) is all achieved by the engine 1. In the case of traveling using both the motor 3 and the engine 1, the target output torque T _t (n) is assigned to each shared target torque between the engine 1 and the motor 3, and command signals are sent to the engine ECU 61 and the inverter ECU 62, respectively. Is output.

The achievement determination means 60f compares the maximum output torque of the motor 3 stored in advance in the memory of the vehicle ECU 60 with the motor shared target torque of the target output torque T _t (n) set by the output torque control means 60e. Thus, it is determined whether or not the target slip ratio control can be achieved. That is, the achievement determination means 60f determines that the target slip ratio control can be achieved if the shared target torque of the target output torque T _t (n) is within the maximum output torque of the motor 3, and the target output torque T _t (n ) Is greater than the maximum output torque of the motor 3, it is determined that the target slip ratio control cannot be achieved.

  The clutch control means 60g detects that either of the clutches 2A and 2B is in the connected state by the clutch switch 57, and the achievement determination means 60f cannot achieve the target slip control with the maximum output torque of the motor 3. If it is determined that there is, the clutches 2A and 2B that are in the connected state are switched to the disconnected state. This is because the output torque of the engine may make it impossible to achieve the target slip control, and this is excluded.

For example, when the output torque of the engine 1 is too high and the drive wheels 8 are slipping, in order to achieve the target output torque T _t (n), a negative torque, that is, a regenerative torque is generated in the motor 3. There may be situations where it is necessary, and if the output torque of the engine 1 is too high, the target output torque T _t (n) may not be achieved even if the motor 3 generates the maximum regenerative torque. In this case, there is a case where the target output torque T _t (n) can be quickly achieved if both of the clutches 2A and 2B are released and the output torque of the engine is released. The above control of the clutch control means 60g pays attention to this point.

The end determination means 60h has a state in which the actual slip ratio λ _r of the drive wheel 8 for determining the end of the target slip ratio control is lower than the preset reference slip ratio λ ₀ (the slip ratio is higher) in advance. When the set time has continued for a predetermined time or when the transmission 4 is a shift speed switching for releasing the power connection between the motor 3 and the drive wheels 8 (in this embodiment, the gear position of the first transmission gear mechanism 4A is changed). If it has been changed), it is determined that the target slip ratio control is to be terminated.

If the state in which the actual slip ratio λ _r is higher than the reference slip ratio λ ₀ continues for a predetermined time or longer, it can be determined that the slip of the drive wheels 8 has been completed (maintained within an allowable range), and target slip ratio control is performed. Is not necessary, and when the transmission 4 is gear shift switching for releasing the power connection between the motor 3 and the drive wheels 8, the motor 3 cannot be used for driving the vehicle, and the target slip ratio control becomes impossible. For this reason, this control end condition is set.

  When it is determined that the control is finished, the output torque control means 60e finishes the target slip ratio control. It is preferable that this end is not performed immediately, but is performed gently by lamp control.

[Action, Effect]
Since the control apparatus for a hybrid electric vehicle according to an embodiment of the present invention is configured as described above, target slip ratio control is performed, for example, as shown in FIG. Note that the processing shown in FIG. 4 is performed in a predetermined control cycle.

As shown in FIG. 4A, first, the vehicle ECU 60 acquires the wheel speed V _fw of the driven wheel 9 detected by the wheel speed sensor 56 as the vehicle body speed V, and the driving wheel detected by the wheel speed sensor 55. 8 wheel speed V _dw is acquired, and connection / disconnection information of the clutches 2A and 2B is acquired from the clutch switch 57 (step S10).
Next, it is determined by the slip detection means 60b whether slip has occurred in the drive wheel 8 (step S20). If slip has occurred in the drive wheel 8, the slip rate calculation means 60c determines the vehicle speed V. From the wheel speed V _dw of the drive wheel 8, the actual slip ratio λ _r when the drive wheel 8 is idling is calculated (step S30).

Next, the target slip ratio setting means 60d determines the connection / disconnection state of the clutches 2A and 2B detected by the clutch switch 57 (step S40), and the running state of the vehicle determined by the vehicle state determination means 60a is the start state. Or the acceleration state (steps S50 and S60), and the target slip ratio λ _tb of the drive wheel 8 is set from these determination results.
The target slip ratio setting means 60d uses the first target slip ratio band λ _tb as the first target slip ratio band λ _tb when starting with the clutches 2A and 2B disengaged (when the output torque of the engine 1 is not involved in the running of the vehicle). A slip ratio band λ _tb 1 is set (step S70). The clutch 2A, at the time of acceleration 2B is in both the cutoff state, a third setting the target slip ratio band lambda _tb 3 as the target slip rate band lambda _tb (step S80).

On the other hand, the target slip ratio setting means 60d sets the target slip ratio band λ _tb as the target slip ratio band λ _tb when starting when either of the clutches 2A, 2B is connected (when the output torque of the engine 1 is involved in the running of the vehicle). A target slip ratio band λ _tb 2 of 2 is set (step S90). The clutch 2A, either 2B is the time of acceleration in the connected state, sets the fourth target slip ratio band lambda _tb 4 as the target slip rate band lambda _tb (step S100).

When the target slip ratio band λ _tb is thus set, the output torque control means 60e sets the actual slip ratio λ _r calculated by the slip ratio calculation means 60c by the target slip ratio setting means 60d when the drive wheel 8 slips. The output torque of the motor 3 and the engine 1 is controlled so as to be within the target slip ratio band λ _tb .
That is, as shown in FIG. 4 (b), to determine whether the actual slip ratio lambda _r is included in the target slip ratio band lambda in _tb (step S110), the actual slip ratio lambda _r is the target slip rate band lambda If included in _tb , the previous correction torque (output torque correction amount) ΔT (n−1) is set to the current correction torque (output torque correction amount) ΔT (n) so as to maintain the current target torque. (Step S140), the output torque correction amount ΔT (n) set to the driver's required torque _Tdr is added to calculate the current target output torque T _t (n) (Step S150).

On the other hand, if the actual slip ratio lambda _r is not included in the target slip ratio band lambda in _tb, that is, when the actual slip ratio lambda _r is deviated from the target slip rate band lambda _tb, the actual slip ratio lambda _r and the target slip rate band lambda Deviation from _tb , that is, a value Δλ necessary for the actual slip ratio λ _r to fall within the target slip ratio band λ _tb is calculated (step S120), and Δλ is subjected to PID processing to obtain the current correction torque (output torque correction). Amount) ΔT (n) is calculated (step S130), and the current output torque correction amount ΔT (n) is added to the driver's required torque _Tdr to calculate the current target output torque T _t (n). (Step S150).

In the output torque control means 60e, the target output torque T _t (n) is all set as the target output torque of the motor 3 when traveling using only the motor 3, and the target output torque when traveling using only the engine 1. If T _t (n) is all the target output torque of the engine 1 and the motor 3 and the engine 1 are used together, the target output torque T _t (n) is assigned to each shared target torque of the engine 1 and the motor 3. Allocate to Thus, the output torque of the motor 3 or the engine 1 is controlled according to the target output torque T _t (n) (step S160).

Thus, in this slip ratio control, when slip of the drive wheel 8 is detected, the drive wheel 8 is determined based on the connection / disconnection state of the clutches 2A and 2B and the traveling state of the vehicle (starting state or acceleration state). set the target slip ratio lambda _t, that the actual slip ratio lambda _r is because controlling the output torque of the motor 3 or the engine 1 so that the target slip ratio lambda _t, to appropriately control the slip ratio of the driving wheels 8 Can do.

In particular, since the target slip ratio λ _t when the vehicle is in a starting state is set to a lower slip side (a higher side if the slip ratio) than a target value when the vehicle is in an accelerating state, The vehicle can be started with certainty suppressed, and by allowing slip to some extent during acceleration during traveling, slip of the drive wheels 8 can be suppressed while ensuring good traveling performance.

Further, the target slip ratio lambda _t, by setting as a band having a width, control can be stabilized.
In particular, when the clutches 2A and 2B are in the connected state, the engine 1 having low follow-up performance with respect to the control command is also controlled. In this case, the target slip ratio band λ _{tb is set} to a relatively wide band, so that the control is stable. Can be made. On the other hand, when the clutches 2A and 2B are in the disconnected state, only the motor 3 having a high follow-up performance with respect to the control command is controlled, so the target slip ratio band λ _tb is relatively narrower than when the clutches 2A and 2B are in the connected state. Since the band is used, the slip state can be more appropriately controlled while stabilizing the control.

Further, since feedback control (here, PID control) based on the difference Δλ between the actual slip ratio λ _t and the target slip ratio λ _t is used for the output torque control of the motor 3 and the engine 1, the motor 3 and the engine 1 Output torque can be controlled appropriately.
Furthermore, if the output torque of the engine 1 is too high, the target output torque T _t (n) may not be achieved even if the maximum regenerative torque is generated in the motor 3, but in this case, either of the clutches 2A and 2B In the open state, the target output torque T _t (n) can be quickly achieved if the engine output torque is removed.

It should be _noted that the state where the actual slip ratio λ _r of the drive wheel 8 for determining the end of the target slip ratio control is lower than the preset reference slip ratio λ ₀ (the higher slip ratio) is set in advance. If the transmission continues for more than a certain time, or if the transmission 4 is a gear shift that opens the power connection between the motor 3 and the drive wheels 8 (in this embodiment, the gear position of the first transmission gear mechanism 4A is changed. Case), the target slip ratio control is terminated, so that unnecessary control is avoided.

[Others]
Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and a part of the embodiment may be changed or the implementation may be performed without departing from the spirit of the present invention. It can be implemented by applying only a part of the form.
For example, in the above-described embodiment, a dual clutch transmission in which the clutch and the transmission gear mechanism are divided into two systems of the odd-numbered stage and the even-numbered stage is illustrated, but the present invention has only one clutch. The present invention can also be applied to a single clutch transmission in which a transmission gear mechanism is not separated.

Further, in the above-described embodiment, an example of application to a large-sized or medium-sized commercial vehicle has been described. However, the object of the present invention is not limited to such an automobile, and can be applied to a vehicle (railway vehicle) other than the automobile. It is.
Further, the engine mounted on the vehicle is not limited to the diesel engine.

1 engine (internal combustion engine)
2 Clutch unit 2A First clutch 2B Second clutch 3 Motor (motor generator)
4 Transmission
4A 1st transmission gear mechanism 4B 2nd transmission gear mechanism 5 Propeller shaft 6 Rear differential (rear differential)
7 Drive shaft 8 Drive wheel (rear wheel)
9 Driven wheel (front wheel)
31 Inverter 32 Battery 40A First input shaft 40B Second input shaft 55 Wheel speed sensor (drive wheel)
56 Wheel speed sensor (driven wheel)
57 Clutch switch (clutch state detection means)
60 Vehicle ECU
60a Vehicle state determination means 60b Slip detection means 60c Slip rate calculation means (slip correspondence value calculation means)
60d target slip ratio setting means (target value setting means)
60e Output torque control means (motor control means and engine control means)
60f Achievement determination means 60g Clutch control means 60h End determination means 61 Engine ECU
62 Inverter ECU
63 Battery ECU

Claims (6)

An engine and a motor as a travel drive source, a clutch that is interposed between the engine and the motor and separates the engine from the drive system, and a drive through which an output torque from the travel drive source is transmitted via a transmission A control device for a hybrid electric vehicle including a wheel,
Clutch state detecting means for detecting the connection / disconnection state of the clutch;
Vehicle state determination means for determining whether the vehicle is running or accelerating;
Slip detecting means for detecting slip of the drive wheel;
Slip corresponding value calculating means for calculating an actual slip ratio of the driving wheel or an actual slip corresponding value corresponding to the actual slip ratio from the vehicle body speed of the vehicle and the wheel speed of the driving wheel;
When slip of the driving wheel is detected by the slip detection means, based on the clutch connection / disconnection state detected by the clutch state detection means and the running state of the vehicle determined by the vehicle state determination means, Target value setting means for setting a target value of a slip corresponding value which is a slip ratio of the driving wheel or a parameter value corresponding to the slip ratio;
When the slip detection means detects the slip of the drive wheel, the traveling drive is performed so that the actual slip correspondence value calculated by the slip correspondence value calculation means becomes the target value set by the target value setting means. A control apparatus for a hybrid electric vehicle, comprising: output torque control means for performing target slip control for controlling output torque of a power source. 2. The control of a hybrid electric vehicle according to claim 1, wherein the target value when the vehicle is in a start state is set to a lower slip side than the target value when the vehicle is in an acceleration state. apparatus. The target value is set as a target value band having a width,
The hybrid electric power according to claim 1 or 2, wherein the target value band when the clutch is in an engaged state is set to a band wider than the target value band when the clutch is in a disengaged state. Automotive control device. The output torque control means outputs the output of the travel drive source by feedback control based on a difference between the actual slip correspondence value calculated by the slip correspondence value calculation means and the target value set by the target value setting means. The control apparatus for a hybrid electric vehicle according to any one of claims 1 to 3, wherein torque is controlled. The output torque control means, when the actual slip corresponding value of the drive wheel has continued for a preset time or longer than the preset reference slip corresponding value, or the transmission The hybrid electric vehicle according to any one of claims 1 to 4, wherein the target slip control is terminated in the case of a shift speed change that opens a power connection between the motor and the drive wheel. Control device. Clutch control means for controlling the clutch;
Achievement determination means for determining whether or not the target slip control can be achieved with the maximum output torque of the motor,
The clutch control means determines that the clutch is detected by the clutch state detection means, and the achievement determination means determines that the target slip control cannot be achieved with the maximum output torque of the motor. The hybrid electric vehicle control device according to any one of claims 1 to 5, wherein when the engine is engaged, the clutch is switched to a disengaged state.

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