JP4265352B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device, and more particularly to a vehicle control device having a function of performing regeneration when performing deceleration traveling.

  Conventionally, for example, a vehicle that is equipped with a hybrid engine system (a system that provides driving force by cooperating both an internal combustion engine and a motor) and converts braking energy generated when the vehicle is decelerating to electric power (regeneration). Vehicles having a function to perform are known. For example, in a hybrid engine, regeneration is performed by using a motor as a generator during deceleration traveling or the like. The electric energy acquired by regeneration is used again as part of the driving force for running the vehicle. By utilizing such a regeneration function, the fuel efficiency of the entire engine system can be improved.

  On the other hand, there is known a continuously variable transmission mechanism (CVT) having a function of changing the gear ratio steplessly when the output (rotational force) of an internal combustion engine or a motor is transmitted to the rotating shaft of a vehicle wheel.

  When regeneration is performed when the vehicle is decelerating, the force transmitted from the rotating shaft of the wheel to the motor via the continuously variable transmission rotates the motor that functions as a generator. At this time, a force (torque) for rotating the motor acts as a braking force for the vehicle.

Here, in the hybrid engine system including the continuously variable transmission mechanism, the gear ratio (output shaft rotational speed / input shaft rotational speed) is increased when the vehicle is decelerating, and the motor acts on the motor from the rotational shaft side of the wheel. The torque is increased and more efficient regeneration is performed (see Patent Document 1).
Japanese Patent Laid-Open No. 9-9415 JP-A-5-79364 JP-A-5-229368

  By the way, in general, the continuously variable transmission mechanism can change the gear ratio only under the condition that the rotating shaft of the wheel is rotating. Further, when the vehicle stops, it is necessary to set the gear ratio to a small value. This is to make the next vehicle start smoothly. However, considering the efficient regeneration as in Patent Document 1 above and adopting a high gear ratio when the vehicle decelerates, the opportunity to lower the gear ratio before stopping the vehicle is lost. If the gear ratio changes suddenly (becomes lower) just before the vehicle stops, the driver will feel uncomfortable.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a good driver during deceleration in a vehicle control device including a regeneration system and a continuously variable transmission mechanism. It is an object of the present invention to provide a vehicle control device that performs efficient regeneration while guaranteeing safety.

In order to achieve the above object, the present invention provides a prime mover, a wheel, a power transmission system that transmits a rotational force between both the prime mover and the wheel, a part of the power transmission system, and the prime mover. A continuously variable transmission mechanism for transmitting a rotational force between the rotational shaft of the wheel and the rotational shaft of the wheel and continuously changing a ratio of rotational speeds between the two shafts; and a rotational force transmitted through the power transmission system. A control device for controlling a vehicle comprising: a generator for generating electricity using speed detection means for detecting the speed of the vehicle; while the speed is above a predetermined value during deceleration of the vehicle Reduces the ratio of the rotational speed of the rotating shaft of the wheel to the rotational speed of the rotating shaft of the prime mover and performs power generation by the generator, and when the speed falls below the predetermined value during deceleration of the vehicle, Rotational speed of motor shaft For against and a torque control means for performing control to reduce the effects of friction torque of the rotational speed ratio to a large and prime mover rotary shaft of the wheel, the predetermined value, the rotational speed of the rotary shaft of the prime mover The sum of the braking torque when the ratio of the rotational speeds of the rotating shafts of the wheels is reduced and the friction torque before executing the control for reducing the action of the friction torque of the prime mover is the rotational shaft of the prime mover. Is equal to the sum of the braking torque when the ratio of the rotational speed of the rotating shaft of the wheel to the rotational speed of the wheel is increased and the friction torque after executing the control to reduce the action of the friction torque of the prime mover. the speed of the vehicle, the torque control means, the large ratio of the rotational speed of the rotary shaft of the wheel relative to the rotational speed of the rotary shaft of the prime mover And summarized in that to reduce the effect of friction torque of the prime mover so as to offset the increase in the braking torque due to Kusuru.

According to this configuration, during deceleration of the vehicle, while the speed exceeds a predetermined value, the ratio of the rotation speed of the wheel rotation shaft to the rotation speed of the rotation shaft of the prime mover is reduced, thereby improving the regeneration efficiency. Can be increased. Then, during deceleration of the vehicle, that the speed When below the predetermined value, the larger the ratio of the rotational speeds of the wheels of the rotary shaft with respect to the rotational speed of the rotary shaft of the engine, and to reduce the effect of friction torque of the prime mover Can do. As a result, it is possible to achieve both improvement in regeneration efficiency and ensuring good drivability.

  A motor, a wheel, a power transmission system that transmits a rotational force between both the motor and the wheel, and a part of the power transmission system, and a rotation shaft of the motor and a rotation shaft of the wheel. A continuously variable transmission mechanism that continuously transmits the rotational force and changes the ratio of the rotational speed between the two shafts steplessly, a generator that generates electric power using the rotational force transmitted through the power transmission system, In the control device for controlling a vehicle, the ratio of the rotational speed of the wheel rotational shaft to the rotational speed of the rotational shaft of the prime mover is reduced while the speed of the vehicle exceeds a predetermined value during deceleration of the vehicle, During deceleration of the vehicle, if the speed falls below the predetermined value, a torque that increases the ratio of the rotation speed of the wheel rotation shaft to the rotation speed of the rotation shaft of the prime mover and cancels the friction torque of the prime mover. Occurrence May be provided with the torque control means that.

  According to this configuration, during deceleration of the vehicle, while the speed exceeds a predetermined value, the ratio of the rotation speed of the wheel rotation shaft to the rotation speed of the rotation shaft of the prime mover is reduced, thereby improving the regeneration efficiency. Can be increased. During deceleration of the vehicle, when the speed falls below the predetermined value, a torque is generated that increases the ratio of the rotational speed of the rotating shaft of the prime mover to the rotational speed of the rotational shaft of the wheel and offsets the friction torque of the prime mover. As a result, the action of the friction torque of the prime mover can be substantially reduced.

The prime mover is an internal combustion engine having a plurality of cylinders,
The torque control means, when the speed of the vehicle is lower than the predetermined value during deceleration, a part of the plurality of cylinders of the engine whose fuel supply has been stopped along with the transition from the normal operation to the deceleration operation The friction torque of the engine is reduced by supplying fuel to the cylinder of the engine, and the predetermined value is a brake when the ratio of the rotational speed of the rotating shaft of the wheel to the rotational speed of the rotating shaft of the prime mover is reduced. The sum of the torque and the friction torque of the engine when the fuel supply is stopped is the rotation of the rotating shaft of the wheel with respect to the rotational speed of the rotating shaft of the prime mover.
The vehicle torque equal to the sum of the braking torque when the speed ratio is increased and the friction torque of the engine when fuel is supplied to some of the cylinders of the engine. The gist is speed .

  According to this configuration, when the speed of the vehicle is lower than a predetermined value during deceleration, fuel is supplied to some of the cylinders of the engine, thereby easily and effectively reducing the friction torque of the engine. Can be reduced.

  According to the present invention, it is possible to achieve both improvement in regeneration efficiency and ensuring good drivability.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode of applying the present invention to a vehicle equipped with a hybrid engine system will be described.

[Basic configuration of engine system]
As shown in FIG. 1, a hybrid engine system (hereinafter referred to as an engine system) 1 includes an internal combustion engine 20, a motor (motor / generator) 30, a generator (motor / generator) 40, a power split mechanism 50, a continuously variable transmission mechanism ( CVT) 60, reduction gear 65, inverter 70, battery 80, electronic control unit (ECU) 90, and the like are included as main components. The internal combustion engine 20 applies a rotational force to the wheels 9 and 10 of the vehicle on which the engine system 1 is mounted, and also drives the generator 40 to generate electric power. The generator 40 may be driven by the internal combustion engine 20 to generate electric power, or may be supplied with electric power from the inverter 70 to apply a rotational force to the internal combustion engine 20. The motor 30 generates electric power by receiving the supply of electric power from the battery 80 or the generator 40 and applying rotational force to the wheels 9 and 10, and conversely, by applying rotational force from the wheels 9 and 10 or the internal combustion engine 20. The battery 80 may be supplied with charging power. The rotation shaft 31 of the motor 30 is connected to the rotation shafts 9a and 10a of the wheels 9 and 10 via a continuously variable transmission mechanism (CVT) 60 and a reduction gear 65.

  The continuously variable transmission mechanism 60 transmits the rotational force of the rotary shaft (input shaft) 31 to the speed reducer 65 via the output shaft 32, and the rotational speed of the input shaft 31 and the output shaft 32 in the process of transmitting the rotational force. The ratio (gear ratio) is continuously changed.

  The crankshaft 24 of the internal combustion engine 20, the rotating shaft 31 of the motor 30, and the rotating shaft 41 of the generator 40 are connected to each other via a power split mechanism 50 incorporating a known planetary gear (not shown). ing. The planetary gear has three rotation shafts geared to each other. Each rotating shaft is coupled to any one of the crankshaft 24, the rotating shaft 31 of the motor 30, and the rotating shaft 41 of the generator 40. The planetary gear has a characteristic that the number of rotations and torque of the remaining rotation shafts are inevitably determined when two rotation speeds (number of rotations) and torque are determined among the three rotation shafts that are constituent elements of the planetary gear. In the engine system 1, by using such a characteristic of the power split mechanism 50, for example, the power generated by the internal combustion engine 20 (rotational force of the crankshaft 24) is converted to the rotating shaft 31 of the motor 30 and the rotating shaft 41 of the generator 40. Can be divided and transmitted. Further, for example, the power generated by the motor 30 and the power generated by the internal combustion engine 20 are used together to rotate the rotating shafts 9a and 10a of the wheels 9 and 10 while driving the generator 40 with the remaining power and the battery 80. Can also be charged. Further, for example, when the vehicle is stopped, power is supplied to the generator 40 with the motor 30 stopped, and the motor is driven to rotate the crankshaft 24 of the internal combustion engine 20 in the non-combustion state. And engine combustion can also be started. Furthermore, by supplying electric power to both the motor 30 and the generator 40 and driving the motor, the crankshaft 24 of the internal combustion engine 20 in the non-combustion state is rotated while the vehicle is running, and engine combustion is started. You can also.

  Further, the engine system 1 is a signal according to the operating state of the internal combustion engine 20, the motor 30, the battery 80, etc. (for example, the rotational speed NE of the internal combustion engine 20), or a signal according to the operating state of the vehicle on which the engine system 1 is mounted. Various sensors (not shown) for outputting (for example, vehicle speed SPD) are provided. These sensors are electrically connected to the ECU 90.

  The ECU 90 includes a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), a backup RAM, a timer counter, and the like. These units, an external input circuit including an A / D converter, and an external A logic operation circuit configured to be connected to the output circuit by a bidirectional bus is provided. The ECU 90 inputs signals output from various sensors (not shown) via an external input circuit, and based on these signals, grasps the operating states of the internal combustion engine 20, the motor 30, the battery 80, etc. Various controls for optimizing the operating state of the engine system 1 based on the operating states of 30, 80, etc. are performed.

[Operation characteristics of continuously variable transmission mechanism]
2A and 2B are perspective views showing an overview of the continuously variable transmission mechanism 60. FIG.

  The continuously variable transmission mechanism 60 includes a primary pulley 61 that is provided around the rotating shaft (input shaft) 31 of the motor 30, a secondary pulley 63 that is provided around the output shaft 62, and grooves C 1 and C 2 on the outer periphery of both pulleys 61 and 63. This is a well-known mechanism comprising a belt or the like that is stretched over the belt. By the hydraulic pressure control based on the command signal from the ECU 90, the widths of the outer peripheral grooves C1, C2 of the pulleys 61, 63 are changed. As a result, the outer diameters of the pulleys 61 and 63 are substantially changed, and the transmission ratio between the input shaft 31 and the output shaft 62 is changed steplessly.

[Vehicle control during deceleration]
In the engine system 1, when a vehicle on which the system 1 is mounted decelerates, the motor 30 functions as a generator, and the braking energy of the wheels 9 and 10 is converted into electric energy (regeneration is performed). The electric energy generated by the regeneration is sequentially stored in the battery 80. When regeneration is performed during deceleration, fuel supply to the internal combustion engine 20 is basically stopped.

  FIG. 3 shows a condition in which the vehicle on which the engine system 1 is mounted is decelerating while maintaining a predetermined acceleration (negative acceleration) and maintaining the speed ratio of the continuously variable transmission mechanism 60 at a predetermined value. The same graph shows the relationship between the braking torque and the vehicle speed transmitted from the output shaft 32 to the input shaft 31, and the relationship between the mechanical loss (friction torque) received by each member such as the internal combustion engine 20 and the vehicle speed. It is shown above. As shown in FIG. 3, the braking torque (hereinafter simply referred to as braking torque) T transmitted from the output shaft 32 to the input shaft 31 decreases substantially linearly corresponding to the decrease (deceleration) of the vehicle speed. On the other hand, the friction torque (hereinafter simply referred to as friction torque) F received by the input shaft 31 from each member such as the internal combustion engine 20 also decreases corresponding to the decrease (deceleration) of the vehicle speed.

  Here, the torque (deceleration torque) D for decelerating the vehicle is generated by the braking torque T and the friction torque F. Specifically, the deceleration torque D and the sum of the braking torque T and the friction torque F are substantially equal (D = T + F). Also, if the deceleration torque D is constant, the braking torque T decreases as the gear ratio (high gear) is applied, and the torque (regenerative torque) that causes the motor 30 to generate electrical energy increases accordingly. That is, at the time of deceleration, it is preferable to increase the efficiency of regeneration (the amount of charge of the battery due to regeneration) by applying the smallest possible gear ratio (high gear) and maintaining the regeneration torque at a large value.

By the way, the continuously variable reduction mechanism 60 needs to be set to a large gear ratio (low gear) when the vehicle is started, but has a mechanical characteristic that cannot change the gear ratio when the vehicle is stopped. Have For this reason, it is necessary to switch the gear ratio of the continuously variable transmission mechanism 60 to a large value (low gear) immediately before the vehicle decelerates and stops.
However, an operation of switching the speed ratio of the continuously variable transmission mechanism 60 from a small value (high gear) to a large value (low gear) immediately before the vehicle stops causes a sudden change in the deceleration torque D, which gives the driver a sense of incongruity.

[Regeneration control during deceleration]
In the engine system according to the present embodiment, the speed ratio of the continuously variable transmission mechanism 60 and the number of operating cylinders are set according to the vehicle speed in order to achieve both improvement in regeneration efficiency and ensuring good drivability when the vehicle is decelerated. By performing the change, an optimal relationship is established between the braking torque T and the friction torque F, and control (regeneration control during deceleration) that suppresses a rapid change in the deceleration torque is executed.

  First, FIG. 4 is a time chart illustrating the transition of the vehicle speed until the vehicle equipped with the engine system 1 travels at a reduced speed and stops. As shown in FIG. 4, in the engine system 1, when the vehicle gradually drops and stops, the speed ratio of the continuously variable transmission mechanism is changed at a timing (t1) when the vehicle speed SPD falls below a predetermined value SPD1 ( Change from high gear to low gear).

  On the other hand, FIG. 5 shows the relationship between a plurality of braking torques and vehicle speeds applicable in the engine system 1 and the relationship between a plurality of friction torques F and vehicle speeds that can also be applied in the engine system 1 under the same conditions as in FIG. These are shown on the same graph.

  When the vehicle speed SPD is equal to or higher than the predetermined value SPD1, the engine system 1 minimizes the gear ratio of the continuously variable transmission mechanism 60 (high gear state) and increases the regeneration efficiency. On the other hand, when the vehicle speed SPD falls below the predetermined value SPD1, the engine system 1 maximizes the gear ratio of the continuously variable transmission mechanism 60 (low gear state) and prepares for the stop of the vehicle (next start of the vehicle).

  Here, as described above, the deceleration torque D corresponds to the sum (T + F) of the braking torque T and the friction torque F. For this reason, when the speed ratio of the continuously variable transmission mechanism 60 is switched from the minimum (high gear state) to the maximum (low gear state) when the vehicle speed SPD is lower than the predetermined value SPD1, the braking torque T increases rapidly (deceleration torque). Suddenly increases), and drivability of the vehicle is impaired.

  Therefore, in the engine system 1, when the vehicle speed SPD falls below the predetermined value SPD1, the speed ratio of the continuously variable transmission mechanism 60 is switched from the minimum (high gear state) to the maximum (low gear state), and the effect of the friction torque F is substantially increased. Reduction control is performed.

  For example, in FIG. 5, when the vehicle speed is a predetermined value SPD1, the deceleration torque D is “T1 + F”. On the other hand, when the vehicle speed is slightly lower than the predetermined value SPD1, the gear ratio of the continuously variable transmission mechanism 60 is switched from the minimum (high gear state) to the maximum (low gear state), and the friction torque is reduced from F to F ′. . As a result, the deceleration torque D becomes a value “T2 + F ′” which is substantially the same as “T1 + F”. When the vehicle speed falls below the predetermined value SPD1, the gear ratio of the continuously variable transmission mechanism 60 is switched from the minimum (high gear state) to the maximum (low gear state) without reducing the friction torque. The deceleration torque D will increase significantly.

  As a specific measure for reducing the friction torque from F to F ′, the reduced cylinder operation is started for the internal combustion engine 20 whose fuel supply has been stopped in accordance with the shift from the normal operation to the deceleration operation. The reduced cylinder operation here means, for example, that the fuel supply to some cylinders among the four cylinders constituting the internal combustion engine 20 is stopped and the fuel supply to the other cylinders is performed.

[Specific control procedure]
FIG. 6 is a routine showing a specific procedure of vehicle control during deceleration according to the present embodiment. This routine is executed periodically (for example, by interruption at a predetermined crank angle) through the ECU 90 during operation of the engine system 1.

  When the process shifts to this routine, the ECU 90 first determines in step S101 whether or not a regeneration condition is satisfied. The ECU 90 determines that the regenerative condition is satisfied, for example, when the vehicle brake pedal is depressed. If the determination in step S101 is affirmative, the ECU 90 moves the process to step S102. On the other hand, if the determination in step S101 is negative, the ECU 90 once exits this routine.

  In step S102, the transmission ratio of continuously variable transmission mechanism 60 is set to a minimum value (high gear state).

  In step S103, it is determined whether or not the vehicle speed SPD is below a predetermined value SPD1. If the determination is affirmative, the process proceeds to step S104. If the determination is negative, the routine is temporarily exited.

  In step S104, the ECU 90 performs the reduced-cylinder operation at the same time as setting the speed ratio of the continuously variable transmission mechanism 60 to the maximum value (low gear state) (step S104).

  After the processing of step S104, the ECU 90 once exits this routine.

  As described above, in the above embodiment, when the vehicle speed SPD falls below the predetermined value SPD1 during deceleration of the vehicle, control is performed to generate engine torque that cancels the friction torque F by performing reduced cylinder operation. did.

  As a result, the friction torque is substantially reduced by the amount that the braking torque T changes discontinuously with the change in the gear ratio of the continuously variable transmission mechanism 60. As a result, when the vehicle decelerates, efficient regeneration can be performed under relatively high vehicle speed conditions, while the deceleration torque can be smoothly reduced as the vehicle speed decreases (abrupt changes in deceleration torque). Can be prevented). Therefore, it is possible to achieve both improvement in regeneration efficiency and ensuring good drivability.

  Since braking torque is generated during deceleration, engine combustion can be continued even with a small amount of fuel supply. For this reason, it is possible to cancel the friction torque by supplying a small amount of fuel to all the cylinders and generating a small engine torque that cannot overcome the friction torque instead of the reduced-cylinder operation. Even if such a control structure is adopted, an effect similar to that of the present embodiment can be obtained.

  In the present embodiment, the present invention is applied to an engine system including a belt-type continuously variable transmission mechanism. However, another mechanism (for example, a trochoidal type) that can change a gear ratio only when the mounted vehicle is running. The present invention can also be applied to an engine system equipped with a continuously variable transmission mechanism.

  In the present embodiment, the present invention is applied to a so-called hybrid engine system. However, the present invention can also be applied to other engine systems having a function of performing regeneration accompanying deceleration of a mounted vehicle.

  In the present embodiment, the transmission ratio of the continuously variable transmission mechanism 60 and the fuel supply to the internal combustion engine 20 are controlled based on the vehicle speed during deceleration. However, instead of the vehicle speed, the gear ratio of the continuously variable transmission mechanism 60 and the fuel supply to the internal combustion engine 20 may be controlled based on the rotational speed of the internal combustion engine 20.

1 is a schematic configuration diagram showing an engine according to an embodiment of the present invention. The perspective view which shows the external appearance of a transmission mechanism. The graph which shows the relationship between a vehicle speed and braking torque, and the relationship between a vehicle speed and friction torque. The time chart which shows the change of the vehicle speed at the time of deceleration, and the change point from a high gear to a low gear. The graph which shows the relationship between a vehicle speed and braking torque, and the relationship between a vehicle speed and friction torque. The flowchart which shows the control procedure of the transmission mechanism at the time of deceleration.

Explanation of symbols

1 .... Engine system 9,10 ... Wheels 9a, 10a ... Rotary shaft (part of power transmission system)
20 .... Internal combustion engine 24 ... Crankshaft (part of power transmission system)
30 ······ Motor 31 ····· Rotation shaft
32 ... Output shaft (part of power transmission system)
40 .. Generator 41... Rotating shaft 50... Power split mechanism 60... Continuously variable transmission mechanism 61.・ ・ ・ ・ Secondary pulley 65 ・ ・ ・ ・ Continuously variable transmission mechanism 70 ・ ・ ・ ・ ・ ・ Inverter 80 ・ ・ ・ ・ ・ ・ Battery C1, C2 ... Groove

Claims (2)

Prime mover,
Wheels,
A power transmission system for transmitting rotational force between both the prime mover and the wheel;
A continuously variable transmission mechanism that forms part of the power transmission system, transmits rotational force between the rotational shaft of the prime mover and the rotational shaft of the wheel, and continuously changes the ratio of rotational speeds between the two shafts. When,
A generator for generating power using the rotational force transmitted through the power transmission system;
A control device for controlling a vehicle comprising:
Speed detecting means for detecting the speed of the vehicle;
While the vehicle is decelerating, while the speed exceeds a predetermined value, the ratio of the rotational speed of the rotating shaft of the wheel to the rotational speed of the rotating shaft of the prime mover is reduced and power is generated by the generator.
Control that increases the ratio of the rotational speed of the rotating shaft of the wheel to the rotational speed of the rotating shaft of the prime mover and reduces the effect of the friction torque of the prime mover when the speed falls below the predetermined value during deceleration of the vehicle Torque control means for executing
With
The predetermined value is
Braking torque when the ratio of the rotational speed of the wheel rotational shaft to the rotational speed of the rotational shaft of the prime mover is reduced, and the friction torque before executing the control for reducing the action of the friction torque of the prime mover; The sum of
Braking torque when the ratio of the rotational speed of the rotating shaft of the wheel to the rotational speed of the rotating shaft of the prime mover is increased, and the friction torque after executing control to reduce the action of the friction torque of the prime mover, In the sum of
The speed of the vehicle to be equal,
The torque control means reduces the action of the friction torque of the prime mover so as to offset the increase in braking torque caused by increasing the ratio of the rotational speed of the wheel rotational shaft to the rotational speed of the rotational shaft of the prime mover. A control apparatus for a vehicle. The prime mover is an internal combustion engine having a plurality of cylinders,
When the speed of the torque control means falls below the predetermined value during deceleration of the vehicle ,
Reducing the friction torque of the engine by supplying fuel to some cylinders of the plurality of cylinders of the engine that have been stopped from the normal operation to the deceleration operation ,
The predetermined value is
The sum of the braking torque when the ratio of the rotational speed of the wheel rotational shaft to the rotational speed of the rotational shaft of the prime mover is made small, and the friction torque of the engine when fuel supply is stopped,
The braking torque when the ratio of the rotation speed of the wheel rotation shaft to the rotation speed of the rotation shaft of the prime mover is increased, and when fuel is supplied to some of the plurality of cylinders of the engine In addition to the friction torque of the engine,
2. The vehicle control device according to claim 1 , wherein the vehicle speeds are equal .

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