JP2006160104A - Controller of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller of a hybrid vehicle which improves following capability to a drive force which demands from the vehicle. <P>SOLUTION: In the controller of the hybrid vehicle of a four-wheel drive in which a clutch 2 is provided between an engine 1 and a motor 3, and which has front wheels 6 driven by the drive force supplied from the engine 1 and the motor 3, and rear wheels 10 driven by a force supplied from a motor 7, the maximum drive force of the rear wheel 10 is calculated based on a predicted road surface friction coefficient μa, and the drive force of the front wheel 6 is calculated from the demanded drive force and the maximum drive force of the rear wheel 10. When the motor 3 cannot realize the drive force of the front wheel 6, the clutch 2 is judged to be engaged. And, when the demanded drive force is distributed, the demand drive force is distributed to the clutch 2 based on the engagement judgment, the engine 1, the clutch 2 and the motors 3 and 7 are controlled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

In a conventional four-wheel drive hybrid vehicle, when a slip occurs in the drive wheel, the drive force that is insufficient in the drive wheel in which the slip has occurred can be compensated by the other drive wheel to ensure the drive force required by the driver as a whole. What is possible is disclosed in US Pat.
JP-A-11-332020

  When the required driving force can be realized using only a motor with a fast torque response when slip occurs, the driving force that is insufficient even when slip occurs can be compensated for by other driving wheels, and the driving force can be realized quickly. However, engine output may be required to supplement the driving force depending on the traveling situation. In this case, since it is necessary to start the engine and engage the clutch, there is a problem that a delay occurs while the engine output is transmitted to the drive shaft, and the required driving force cannot be realized quickly.

  The present invention has been made in view of the above problems. Even when slipping occurs regardless of the driving situation, the response delay due to engine start-up and clutch engagement, that is, the followability to the required driving force is improved, and the required driving is achieved. An object of the present invention is to provide a control device for a hybrid vehicle that quickly realizes force.

  In the present invention, a clutch is provided between the engine and the first motor, the first driving wheel driven by the power generated by the engine and the first motor, and the second driving wheel driven by the power generated by the second motor, And a power storage device that supplies electric power to the first motor and the second motor and stores the electric power generated by the first motor and the second motor. A required driving force calculating means for calculating a required driving force, a road surface friction coefficient estimating means for estimating a road surface friction coefficient of a traveling road surface, and generating slip on the second driving wheel based on the road surface friction coefficient. An anti-slip driving force calculating means for calculating an anti-slip driving force, a first driving force calculating means for calculating a first driving force to the first driving wheel based on the anti-slip driving force and the required driving force, A clutch engagement determining means for determining whether or not the driving force can be realized by the first motor, and for determining the engagement between the engine and the first motor by the clutch when the first driving force cannot be realized by only the first motor; Based on the clutch engagement determining means, a distributed drive that calculates a distributed drive force that distributes the required drive force to the first drive wheel and the second drive wheel so that the first drive wheel and the second drive wheel do not slip. A force calculating means; and a driving force control means for engaging or disengaging the clutch based on the clutch engagement determining means and controlling the driving force supplied from the engine, the first motor, and the second motor based on the distributed driving force. Prepare.

  According to the present invention, the first driving wheel (front wheel) driven by the power generated by the engine and the first motor, the second driving wheel (rear wheel) driven by the power generated by the second motor, the first motor, And a power storage device that supplies electric power to the second motor and stores the electric power generated by the first motor and the second motor. A control device for a hybrid vehicle capable of four-wheel drive is provided based on a road surface friction coefficient. The anti-slip driving force in a range in which the two drive wheels do not slip is calculated, and the first driving force is calculated from the required driving force and the anti-slip driving force. The clutch is determined to be engaged depending on whether the first driving force can be realized by the first motor. Further, when the required driving force is distributed to the first driving wheel and the second driving wheel, it is distributed based on the clutch engagement / disengagement determination, and the clutch, engine, first motor, and second motor are controlled. When it is necessary to supply the driving force from the engine, the response delay of the driving force due to the start of the engine and the engagement of the clutch can be eliminated, and the followability to the required driving force can be improved.

  A hybrid vehicle according to a first embodiment of the present invention will be described with reference to the schematic configuration diagram of FIG. The power train of the hybrid vehicle according to this embodiment includes the engine 1 and the like, and includes the first driving force transmission path 20 that drives the first driving wheels 6 and the motor 7 and the like, and drives the second driving wheels 10. It is a hybrid vehicle capable of four-wheel drive that includes a second driving force transmission path 21 and a power supply path 22 that supplies power to the motors 3 and 7.

  The first driving force transmission path 20 transmits the power between the engine 1 that is an internal combustion engine, a motor (first motor) 3 that is the same as or independent of the engine 1, and power of the vehicle, and between the engine 1 and the motor 3. The clutch 2 for switching, the continuously variable transmission 15 for changing the rotational speed and rotational radius of the output shaft for transmitting power from the engine 1 and the motor 3, and the speed reducing device 4 for reducing the rotational speed transmitted from the continuously variable transmission 15. And a differential device 5 that transmits the torque transmitted through the reduction gear 4 to the first drive wheels 6.

  The clutch 2 is a powder clutch and can adjust the transmission torque. A dry single plate clutch or a wet multi-plate clutch may be used instead of the powder clutch.

  The continuously variable transmission 15 uses a belt-type continuously variable transmission, but in addition to the belt-type, a toroidal continuously variable transmission, a transmission that changes in stages, or a transmission that uses planetary gears may be used. .

  The second driving force transmission path 21 includes a motor (second motor) 7 that serves as power for the vehicle, a reduction device 8 that reduces the rotational speed transmitted from the motor 7, and torque that is transmitted via the reduction device 8. A differential device 8 for transmitting to the second drive wheel 10 is provided.

  Although the motors 3 and 7 use AC motors, DC motors may be used instead.

  The power supply path 22 is electrically connected to the motors 3 and 7, the power storage device 12 that supplies power to the motors 3 and 7, the inverter 11 disposed between the motor 3 and the power storage device 12, and the motor 7 And an inverter 13 disposed between the power storage device 12 and the power storage device 12.

  The power storage device 3 uses, for example, various types of batteries such as lithium ion batteries, nickel / hydrogen batteries, lead storage batteries, and electric double layer capacitors, so-called power capacitors.

  The inverter 11 converts the DC charging power of the power storage device 12 into AC and supplies the power to the motor 3, and changes the AC generated power of the motor 3 to DC power to charge the power storage device 3. The inverter 13 converts the DC charging power of the power storage device 12 into AC and supplies the motor 7 with power, and changes the AC generated power of the motor 7 to DC power to charge the power storage device 3. In the case where a DC motor is used for the motors 3 and 7, DC / DC converters are used instead of the inverters 11 and 13.

  Further, based on an accelerator operation from a driver (not shown) and a vehicle speed signal from a wheel speed sensor (not shown), it is determined what to do with the operating state of the engine 1 and the operating states of the motors 3 and 7, and the determination result and the accelerator An integrated controller 14 is provided that generates command values for the engine 1, the clutch 2, the motors 3 and 7, and the continuously variable transmission 15 in response to a request from the driver through operation.

  Here, a case that is particularly effective in the hybrid vehicle control method according to the embodiment of the present invention will be described.

  Normally, a hybrid vehicle normally performs idling stop when stopped. And when the driver starts the accelerator operation, the engine operation efficiency at the time of starting is not good, so unless the vehicle is suddenly accelerated, it starts with the driving force supplied from the motor until it reaches a predetermined speed or a predetermined required driving force. In other words, the motor continues running until it reaches the limit of high-efficiency operation of the motor or the limit of output.

  At this time, if the stopped engine is rotated by the motor, a friction loss occurs, so the clutch is released. When a predetermined speed or a predetermined required driving force is reached, the engine is started, the clutch is engaged, and the driving is switched to the driving force supplied from the engine. It should be noted that the engine is started quickly with some margin in order to quickly switch to engine running.

  The above is the start of a general hybrid vehicle.

  In the case of a hybrid vehicle in which the front and rear wheels (first driving wheel 6 and second driving wheel 10) are provided with motors (motors 3 and 7), the speed limit or required driving force of the motor travel is the capability of the motors of the front and rear wheels. Total. For example, assuming that the rear wheel load of the vehicle is lighter than the front wheel load, if the road surface friction coefficient μ is low, slip may occur on the drive wheels. In this case, since the rear wheel load is light, the rear wheel starts to slip first. In this case, since the driving force of the rear wheels is reduced, the driving force less than the required driving force is distributed to the front wheels having a heavy wheel load and a margin of friction.

  However, if the drive request for the motor that drives the front wheels exceeds the performance of the motor, it is necessary to distribute the engine drive force by starting the engine and engaging the clutch for the required drive force that is insufficient for the front wheels, The required driving force for the time loss such as engine start cannot be satisfied, and the drivability is deteriorated. Such a phenomenon is not limited to the case where the wheel load of the rear wheels is light, for example, and the performance of the motor (motor 7) that drives the rear wheels compared to the motor (motor 3) that drives the front wheels is improved. It also occurs in some cases. That is, there is a difference in driving force between the front wheels and the rear wheels during motor travel, and the dependence on the rear wheel motor increases near the limit of motor travel. In such a case, since the front wheel motor is also close to the limit, the driving force cannot be distributed without waiting for the engine to start even though there is a margin in the friction limit.

  In this embodiment, for example, when slipping of the second driving wheel 10 is expected, the first driving wheel is started by starting the engine 1 and engaging the clutch 2 before exceeding the limit of motor driving. The driving force of 6 can be afforded, and the drivability of the hybrid vehicle can be improved.

  Next, the driving force control of the hybrid vehicle in the integrated controller 14 will be described using the flowchart of FIG. This flowchart is performed every predetermined time, for example, every 10 msec.

  In step S100, based on a vehicle speed (km / h) obtained from an output from a vehicle speed sensor (not shown) such as a magnetic or optical encoder, and an accelerator opening (deg) obtained from an output from an accelerator position sensor (not shown). The required driving force F (N) is calculated by searching the map shown in FIG. The map of FIG. 3 has a tendency that a larger driving force is obtained as the vehicle speed is lower. However, the detailed setting may be obtained in advance by adjusting the value of the map so as to follow the driver's feeling through experiments or the like. Further, a first-order lag process may be performed on the obtained value (step S100 constitutes a required driving force calculation means).

  In step S101, the road surface friction coefficient μ is estimated using the rotational speed of the wheel calculated using the vehicle speed sensor. As an estimation method, for example, as described in JP-A-11-78843, a method for estimating a road surface friction coefficient gradient, which is a gradient of a friction coefficient between a tire and a road surface, or JP-A-10-114263 is described. As described above, as a physical quantity that can be handled equivalently to a road surface friction coefficient gradient, there is a method of estimating based on a braking torque gradient or a driving torque gradient with respect to a slip speed (step S101 constitutes a road surface friction coefficient estimating unit). ).

  In step S102, the predicted road surface friction coefficient μa of the road to be traveled is estimated. In estimating the expected road surface friction coefficient μa, an output from an outside air temperature sensor (weather information detecting means) (not shown) is used. For example, the road surface friction coefficient μ estimated in step S101 is equivalent to a dry road surface and the outside air temperature is 10 ° C. or higher. If there is, it is considered that the frequency of change to the snow or ice / ice freezing road surface is extremely low, so it can be assumed that the road surface friction coefficient corresponding to the wet road surface changes. In addition, rain or snow weather is assumed from the condition of the wiper operation, and if the temperature is 10 ° C or higher, it is considered that the frequency of change to snow or icing road surface is very low. It can be assumed that the range is equivalent to the road surface. Further, if the temperature is less than 10 ° C., it can be assumed that the road surface friction coefficient is equivalent to snow or icy road. Further, if weather information is obtained using means for obtaining external information such as radio or the Internet, the assumption of a change in the friction coefficient of the road surface is more accurate. The predicted road friction coefficient μa is estimated based on the above information. In the example, the predicted road friction coefficient μa is estimated at a temperature of 10 ° C., but it is not necessarily 10 ° C., and a value adjusted so that it can be assumed with high accuracy may be used (step S102 is a change in road friction coefficient). Constitutes an estimation means).

  In step S103, when the predicted road surface friction coefficient μa estimated in step S102 is reached, the clutch 2 is engaged, and whether or not the driving force from the engine 1 is required in addition to the driving force supplied by the motors 3 and 7 is determined. Judging. Hereinafter, the clutch engagement / disengagement determination control performed in step S103 will be described with reference to the flowchart of FIG.

  In step S200, the required driving force F calculated in step S100 is read, and in step S201, the predicted road surface friction coefficient μa estimated in step S102 is read.

In step S202, the maximum driving force that can be generated by the first driving wheel 6 and the second driving wheel 10 at the predicted road surface friction coefficient μa,
Ffa_lmt = μa · Mf · g Formula (1)
Fra_lmt = μa · Mr · g Formula (2)
Calculated by In the following description, the first driving wheel 6 is referred to as a front wheel 6, and the second driving wheel 10 is referred to as a rear wheel 10. Ffa_lmt is the maximum driving force of the front wheel 6 that can be generated within a range where no slip occurs in the predicted road surface friction coefficient μa, and Fra_lmt is after the possible generation in a range where no slip occurs in the predicted road surface friction coefficient μa This is the maximum driving force of the wheel 10 (anti-slip driving force). Further, Mf is a load applied to the front wheel 6, Mr is a load applied to the rear wheel 10, and g is a gravitational acceleration. That is, Ffa_lmt is the maximum driving force at which the front wheel 6 does not slip when the front wheel 6 is driven by the motor 3 and the engine 1, and Fra_lmt is the maximum at which the rear wheel 10 does not slip when the rear wheel 10 is driven by the motor 7. It is a driving force (Step S202 constitutes a slip prevention driving force calculating means).

  In step S203, when the distribution of the driving force generated at the front wheels 6 and the rear wheels 10 is changed so that no slip occurs, it is determined whether or not the required driving force F can be satisfied quickly. The determination as to whether or not the required driving force F can be satisfied here is made from the engine 1 when the driving force is distributed to the front wheels 6 and the rear wheels 10 within a range where the predicted road surface friction coefficient μa does not cause a slip. It is determined whether or not the vehicle can be driven only by the driving force from the motors 3 and 7 without using the driving force.

  Here, whether the deviation (first driving force) obtained by subtracting the maximum driving force Fra_lmt that can be supplied without causing slip at the rear wheel 10 from the required driving force F is larger than the maximum driving force that can be supplied by the motor 3. Judge by no. When the deviation between the required driving force F and the maximum driving force Fra_lmt of the rear wheel 10 is larger than the maximum driving force of the motor 3, the process proceeds to step S204, where the required driving force F and the maximum driving force Fra_lmt of the rear wheel 10 are Is smaller than the maximum driving force of the motor 3, the process proceeds to step S205 (step S203 constitutes the first driving force calculating means).

  In the control of step S203, the driving force at the rear wheel 10 is set as the maximum driving force Fra_lmt, and the deviation between the required driving force and the maximum driving force Fra_lmt is compared with the maximum driving force that can be supplied from the motor 3. That is, the driving force applied to the rear wheel 10 driven by the motor 7 is preferentially used, and the driving force required for the front wheel 6 is reduced. When the driving force required for the front wheels 6 is reduced, the vehicle can be driven by the driving force supplied only from the motor 3 without using the driving force supplied from the engine 1 with respect to the required driving force. The case increases. That is, the number of cases where the vehicle is driven by the driving force supplied from the motor 3 and the motor 7 increases.

  When it is necessary to use the driving force from the engine 1 when the required driving force F is distributed, it is necessary to start the engine 1 and to engage the clutch 2 for transmitting the torque of the engine 1. The followability to F becomes worse. On the other hand, when the required driving force F can be satisfied with the driving force supplied from the motors 3 and 7 provided in the front wheels 6 and the rear wheels 10, the speed is faster than when torque is transmitted from the engine 1. The required driving force F can be satisfied by the torque response.

  The number of times of releasing the clutch 2 from the engine 1 can be increased by the control in step S203, and the number of times of supplying the driving force from the engine 1 can be decreased. Therefore, the number of operations (time) of the engine 1 can be reduced, and fuel consumption in the engine 1 can be reduced.

  In step S204, the deviation between the required driving force F and the maximum driving force Fra_lmt of the rear wheel 10 is larger than the maximum driving force of the motor 3, that is, the required driving force F is greater than the maximum driving force that can be realized by the motors 3 and 7. Since it is large, in order to make up for the shortage, it is determined whether the clutch 2 for supplying driving force from the engine 1 is engaged. Since the determination of engagement of the clutch 2 is performed based on the predicted road surface friction coefficient μa predicted in step S103, the driving force distribution with the clutch 2 engaged in advance is performed in preparation for a change in the road surface friction coefficient μ in the driving force distribution calculation control described later. Therefore, there is no delay in the driving force response generated in the process of starting the engine 1 and engaging the clutch 2, and the required driving force can be realized promptly even after the road surface friction coefficient changes.

  On the other hand, in step S202, the deviation between the required driving force F and the maximum driving force Fra_lmt of the rear wheel 10 is smaller than the maximum driving force that can be supplied from the motor 3, that is, the driving in which the required driving force F is supplied from the motors 3 and 7. If it is determined that the required driving force F is realized by the motors 3 and 7 in step S205, the power P (kW) consumed by the motors 3 and 7 and the current power storage device 12 are stored. The stored power amount P0 (kW), that is, outputable power P0 is compared. If the power P consumed by the motors 3 and 7 is larger than the stored amount P0 stored in the power storage device 12, the process proceeds to step S206, and the power P consumed by the motors 3 and 7 is stored in the power storage device 12. If it is smaller than the stored power amount P0, the process proceeds to step S207 (step S205 constitutes an input / output available power calculation means).

The power P consumed by the motors 3 and 7 is mapped in advance to the operating characteristics of the motors 3 and 7, and the power P consumed by the motors 3 and 7 including the lost power is accurately determined from the map. You can ask well. On the other hand, the amount P0 of electricity stored in the electricity storage device 12 is
P0 = Vmin × (V0−Vmin) / R / 1000 Formula (3)
Calculated by Vmin (V) is a lower limit voltage that can be used by power storage device 12, V0 (V) is a current open circuit voltage of power storage device 12, and R (Ω) is an internal resistance of power storage device 12.

  In step S206, the electric power P consumed by the motors 3 and 7 cannot be supplied by the electric storage amount P0 of the electric storage device 12, that is, the required driving force F cannot be supplied by the driving force supplied from the motors 3 and 7. Therefore, in order to make up for the shortage, it is determined whether the clutch 2 for supplying driving force from the engine 1 is engaged.

  In step S205, the amount P0 stored in the power storage device 12 and the power P consumed by the motors 3 and 7 were compared. However, when the operating efficiency of the motors 3 and 7 deteriorates, that is, the driving force supplied from the engine 1 was added. However, if the energy efficiency is better than driving with only the motors 3 and 7, the process proceeds to step S206, and the engagement determination of the clutch 2 may be performed.

  In step S207, the electric power P consumed by the motors 3 and 7 can be supplied by the electric storage amount P0 of the electric storage device 12, so that the clutch 2 is determined to be disengaged (steps S203 to S207 constitute the clutch engagement determination means). To do).

  In the driving force distribution calculation control to be described later, based on the predicted road surface friction coefficient μa, that is, the predicted road surface condition, or by determining whether the clutch 2 is engaged or disengaged from the power storage state of the power storage device 12 by the above control. When the required driving force F is distributed, the driving force distribution with the clutch 2 engaged in advance can be performed, so that there is no delay in the driving force response generated in the process of starting the engine 1 and engaging the clutch 2, and the road surface The required driving force can be realized quickly even after the friction coefficient is changed.

  Next, in step S104, driving force distribution calculation control for calculating the driving force (distributed driving force) that is actually distributed to the front wheels 6 and the rear wheels 10 is performed. Hereinafter, the driving force distribution calculation control will be described with reference to the flowchart of FIG. 5 (step S104 constitutes the distributed driving force calculation means).

  In step S300, the required driving force F calculated in step S100 is read, and in step S301, the road surface friction coefficient μ estimated in step S101 is read. In step S302, the clutch 2 engagement / disengagement determination determined in step S103 is read.

In step S303, the maximum driving force that can be generated in the front wheels 6 and the rear wheels 10 based on the road surface friction coefficient μ read in step S301,
Ff_lmt = μ · Mf · g Formula (4)
Fr_lmt = μ · Mr · g Formula (5)
Calculated by Note that Ff_lmt is the maximum driving force of the front wheel 6 that can be generated in the range where no slip occurs in the predicted road surface friction coefficient μ, and Fr_lmt can be generated in the range where no slip occurs in the road surface friction coefficient μ. This is the maximum driving force of the rear wheel 10.

  In step S304, it is determined whether or not the total value F_lmt of the maximum driving force of the front wheels 6 and the rear wheels 10 is greater than the requested driving force F read in step S300. If the total value F_lmt of the maximum driving force of the front wheel 6 and the rear wheel 10 is larger than the required driving force F, the process proceeds to step S305, where the total value F_lmt of the maximum driving force of the front wheel 6 and the rear wheel 10 is the required driving force. If smaller than F, the process proceeds to step S308.

  In step S305, it is determined whether or not the engagement or disengagement determination of the clutch 2 read in step S302 is the disengagement determination. If the clutch 2 is determined to be released, the process proceeds to step S306. If the clutch 2 is determined to be engaged, the process proceeds to step S307.

  In step S306, the driving force distributed to the front wheels 6 and the rear wheels 10 is calculated so as to satisfy the required driving force F within the range of the driving force in which the front wheels 6 and rear wheels 10 calculated in step S303 do not cause slip. Here, since it is determined that the clutch 2 is released in step S305, the required driving force F can be satisfied by the driving force supplied from the motors 3 and 7. The driving force applied to the front wheels 6 and the rear wheels 10, that is, the driving force supplied by the motor 3 and the motor 7 may be any distribution as long as the driving force distribution satisfies the required driving force F. However, it is desirable to travel in such a distribution that the discharge power from the power storage device 12 is reduced.

  In step S307, the clutch 2 is engaged, and the required driving force F is supplied to the front wheels 6 and the rear wheels 10 when the required driving force F is supplied from the engine 1 and the motors 3 and 7, that is, supplied by the engine 1 and the motor 3. The driving force to the front wheel 6 and the driving force to the rear wheel 10 supplied by the motor 7 are calculated. In addition, in order to reduce the fuel consumption of the running engine 1, the charging power to the power storage device 12 is increased as much as possible with respect to the fuel consumed by the engine 1 (including that the discharging power is reduced). Distribution is desirable. Since such distribution can be obtained from the fuel consumption characteristics of the engine shown in FIG. 6 and the loss characteristics of the motor shown in FIG. 7, the distribution data corresponding to the driving situation is stored in the storage device, and the data during the driving is stored. This can be realized by reading

  If it is determined in step S304 that the total value of the maximum driving forces of the front wheels 6 and the rear wheels 10 is smaller than the required driving force F, the driving force of the front wheels 6 is set to the maximum driving force Ff_lmt in step S308, and the rear wheels The driving force of 10 is set as the maximum driving force Fr_lmt, and the driving force is distributed between the motor 3 and the engine 1 for realizing the maximum driving force Ff_lmt in the front wheels 6. It is desirable that the driving force distribution in the motor 3 and the engine 1 travels in such a distribution that the discharge power from the power storage device 12 becomes small.

  In step S105, the torques of the motors 3 and 7 and the engine 1 and the gear ratio of the continuously variable transmission 15 are controlled so as to be the driving force calculated by the driving force distribution calculation control in step S104 (step S105 is the driving force control). Means).

  Even after the road surface friction coefficient is changed, the speed ratio of the continuously variable transmission 15 is controlled in order to quickly realize the required driving force F by the torque change of the engine 1 and the motors 3 and 7. FIG. 8 shows an image of changes in the engine operating point when the road surface friction coefficient μ decreases during traveling and the driving force distribution to the front wheels 6 increases. A broken line is an equal output line, and an equal output is generated at the operating points (a) and (b). The arrow indicates the change in operating point when the torque increases after the change in the road surface friction coefficient. In (a), it can be seen that there is a limit on the maximum torque and the required driving force cannot be realized. In this case, since it is necessary to increase the output by increasing the rotation speed, the required driving force cannot be realized quickly. On the other hand, in (b), the required torque is realized within the limit range of the maximum torque. Thus, even when the engine 1 generates equal output, it is necessary to select an operating point assuming that the road surface friction coefficient has changed. Although the engine operating point has been described above, it is necessary to select the operating point based on the gear ratio so that the motor 3 that operates at the same rotation speed as the engine speed when the clutch is engaged similarly satisfies the required driving force by increasing the torque. There is. In this embodiment, the gear ratio is set so as to operate at the operating point (b) where the required driving force can be achieved by increasing the torque even after the road surface friction coefficient changes.

  With the above control, the driving force supplied from the engine 1 and the motors 3 and 7 is controlled according to the engaged / disengaged state of the clutch 2 or the amount of power stored in the power storage device 12, and the followability to the required driving force F is improved. be able to.

  The effect of 1st Embodiment of this invention is demonstrated.

  The maximum driving force Fra_lmt of the rear wheel 10 is calculated from the predicted road surface friction coefficient μa of the traveling road surface, and the deviation between the required driving force F required for the vehicle and the maximum driving force Fra_lmt is compared with the driving force that can be supplied by the motor 3. When the deviation cannot be supplied by the motor 3, it is determined to engage the clutch 2. When the required driving force F is distributed to the front wheels 6 and the rear wheels 10, the required driving force F is distributed to the clutch 2 based on the engagement / disengagement determination, and the engagement / disengagement of the clutch 2 is controlled, and the engine 1 and the motor The driving forces of the front wheels 6 and the rear wheels 10 are controlled by controlling the torques of 3 and 7. As a result, when only the driving force supplied from the motors 3 and 7 cannot satisfy the required driving force F, the driving force can be quickly supplied from the engine 1 and the followability to the required driving force F is improved. can do.

  When the clutch 2 is determined to be engaged / disengaged, a deviation from the required driving force F to the maximum driving force Fra_lmt of the rear wheel 10 is determined, and it is determined whether the deviation is a driving force that can be supplied by the motor 3. In other words, the driving force of the rear wheel 10 is preferentially used, and further, the driving force of the front wheel 6 is reduced by maximizing the driving force, and the engagement of the clutch 2 is reduced. As a result, the engagement of the clutch 2, that is, the supply of driving force from the engine 1, can be reduced, and the amount of fuel consumed by the engine 1 can be reduced.

  Further, when the electric power P necessary for realizing the required driving force F by the motor 3 and the motor 7 is larger than the electric storage amount P0 stored in the electric storage device 12, the engine 1 is determined by determining whether the clutch 2 is engaged. Thus, the driving force can be quickly supplied, and the followability to the required driving force F can be improved.

  The clutch 2 is determined to be engaged / disengaged from the predicted road friction coefficient μa predicted from the road surface to be driven, and the driving force is distributed to the front wheels 6 and the rear wheels 10 based on the clutch 2 engagement / disengagement determination. Therefore, the clutch 2 can be quickly engaged, and the driving force can be quickly supplied from the engine 1 to the front wheels 6. As a result, the response delay time of the clutch 2 can be eliminated, and the followability to the required driving force F can be improved.

  Since the driving ratio distributed to the front wheels 6 can be realized only by increasing the torque of the engine 1 and the motor 3 when the road surface friction coefficient μ changes, the gear ratio of the continuously variable transmission 15 that is running is controlled. The required driving force F can be quickly realized even after the change of the road surface friction coefficient μ without being limited to the torque upper limit value of the engine 1 or the motor 3.

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

  It can be used for a four-wheel drive hybrid vehicle.

It is a schematic block diagram of the hybrid vehicle of this invention. It is a flowchart which shows the driving force control of this invention. 3 is a map for calculating a required driving force in the present invention. 4 is a flowchart of clutch engagement / disengagement determination control according to the present invention. It is a flowchart of the driving force distribution calculation control of the present invention. It is a map which shows the fuel consumption characteristic of the engine of this invention. It is a map which shows the loss characteristic of the motor of this invention. It is a map which shows an engine operating point change when a road surface friction coefficient changes.

Explanation of symbols

1 Engine 2 Clutch 3 Motor (first motor)
6 Front wheel (first drive wheel)
7 Motor (second motor)
10 Rear wheel (second motor)
12 power storage device 14 integrated controller 20 first driving force transmission path 21 second driving force transmission path 22 power supply path

Claims (7)

A first drive wheel provided with a clutch between the engine and the first motor, and driven by power generated by the engine and the first motor;
A second drive wheel driven by the power generated by the second motor;
In a control device for a hybrid vehicle capable of four-wheel drive, comprising: a power storage device that supplies electric power to the first motor and the second motor and stores electric power generated by the first motor and the second motor. ,
Requested driving force calculating means for calculating required driving force required for the vehicle;
Road surface friction coefficient estimating means for estimating the road surface friction coefficient of the traveling road surface;
An anti-slip driving force calculating means for calculating an anti-slip driving force that does not cause a slip on the second driving wheel based on the estimated road surface friction coefficient;
First driving force calculating means for calculating a first driving force to the first driving wheel based on the anti-slip driving force and the required driving force;
It is determined whether or not the first driving force can be realized by the first motor. When the first driving force cannot be realized only by the first motor, the clutch and the first motor are fastened by the clutch. Clutch engagement determination means for determining
Distributing drive that distributes the required driving force to the first driving wheel and the second driving wheel so that the first driving wheel and the second driving wheel do not slip based on the clutch engagement determination means. Distributed driving force calculating means for calculating force;
Driving force control means for engaging or disengaging the clutch based on the clutch fastening determination means, and controlling driving force supplied from the engine, the first motor, and the second motor based on the distributed driving force; A control device for a hybrid vehicle, comprising:   2. The hybrid vehicle control device according to claim 1, wherein the first driving force calculation unit subtracts the anti-slip driving force from the required driving force. 3.   The hybrid vehicle control device according to claim 1, wherein the anti-slip driving force is a maximum driving force within a range in which the second driving wheel does not cause the slip. Input / output possible power calculation means for calculating power that can be input / output of the power storage device,
The clutch engagement determining means determines engagement of the engine and the first motor by the clutch when electric power for realizing the first driving force by the first motor cannot be supplied from the power storage device. The control apparatus of the hybrid vehicle as described in any one of Claim 1 to 3 characterized by these. The hybrid vehicle is a hybrid vehicle including a continuously variable transmission that is connected to the first motor and the engine and transmits the power generated by the first motor and the engine to the first drive shaft.
The driving force control means includes
Gear ratio calculating means for calculating a gear ratio of the continuously variable transmission for realizing the distributed driving force distributed to the first drive wheels;
The hybrid vehicle control device according to any one of claims 1 to 4, further comprising: a gear ratio control unit that changes a gear ratio of the continuously variable transmission. Road surface friction coefficient change estimating means for estimating a change in the road surface friction coefficient of the traveling road surface,
6. The anti-slip driving force calculating unit calculates the anti-slip driving force based on a value after the change of the road surface friction coefficient estimated by the road surface friction coefficient change estimating unit. The control apparatus of the hybrid vehicle as described in any one. The road surface friction coefficient change estimating means includes weather information detecting means for detecting weather information,
The hybrid vehicle control device according to claim 6, wherein a change in the road surface friction coefficient is estimated based on the weather information.

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