JP4958516B2 - Four-wheel drive control device - Google Patents

Description

  The present invention relates to a four-wheel drive control device for an electric vehicle using an electric motor as a drive source and a high-brid electric vehicle using both an engine and an electric motor as a drive source.

  As a conventional four-wheel drive control device, there is one that drives, for example, left and right front wheels by an output of an engine as a main drive source, and drives, for example, left and right rear wheels by an output of an electric motor as a sub drive source.

  In this four-wheel drive control device, A / T shift signal, wheel speed signal, engine speed signal, motor speed signal, throttle opening signal, ABS (Antilock Brake System) signal, fail signal, TCS (Traction Control System) In response to various signals such as signals, the output of the electric motor is intermittently switched between the two-wheel drive state and the four-wheel drive state.

  However, the conventional four-wheel drive control device has a problem of switching to the two-wheel drive state against the driver's intention based on the throttle opening signal, the A / T shift signal, and the like during four-wheel drive travel.

  For example, when driving while adjusting the accelerator delicately at an intersection, etc., if there is no slip on the wheels, the controller determines that the vehicle is in the engine brake state when the accelerator is returned, and the four-wheel drive state is driven by two-wheel drive. There is a case of switching to a state.

  Due to such switching, there is a problem that the driver feels uncomfortable when traveling at an intersection, and improvement has been desired.

JP 2000-355227 A

  The problem to be solved by the present invention is that automatic switching from a four-wheel drive state to a two-wheel drive state against the driver's intention gives a sense of incongruity.

The present invention automatically switches between a two-wheel drive state and a four-wheel drive state according to a traveling state grasped based on at least throttle opening information of the automobile so as not to give a sense of incongruity due to automatic switching. In the four-wheel drive control device that controls the auto mode to be controlled by the control means, the control means includes a lock auto mode, and is provided with a switch that allows the auto mode and the lock auto mode to be selected. The main feature is that the switching control from the four-wheel drive state to the two-wheel drive state is regulated by the throttle opening information to maintain the four-wheel drive state.

According to the present invention, when the lock auto mode is selected by the switch, switching control from the four-wheel drive state to the two-wheel drive state based on the throttle opening information can be restricted and the four-wheel drive state can be maintained.

  Accordingly, it is possible to maintain the four-wheel drive state during a delicate accelerator operation while automatically switching between the two-wheel drive state and the four-wheel drive state.

  The purpose of avoiding a sense of incongruity due to automatic switching is realized by restricting switching control from a four-wheel drive state to a two-wheel drive state by a throttle opening signal.

[Overall configuration of four-wheel drive vehicle]
FIG. 1 is a skeleton plan view of a four-wheel drive vehicle to which a four-wheel drive control device according to an embodiment of the present invention is applied. As shown in FIG. 1, the four-wheel drive vehicle 1 is a high-brid electric vehicle that uses both an engine and an electric motor as drive sources, and is an engine 3 as an internal combustion engine that is a main drive source, and a sub drive source. And an electric motor 5.

  The engine 3 drives left and right front wheels 7 and 9 as main drive wheels, and the electric motor 5 drives left and right rear wheels 11 and 13 as auxiliary drive wheels. However, the front wheels can be driven by the electric motor 5 as the auxiliary drive source, and the rear wheels 11 and 13 can be driven by the engine 3 as the main drive source. The left and right front wheels 7 and 9 are provided with disc brakes 15 and 17 as braking means, and the left and right rear wheels 11 and 13 are also provided with brakes 16 and 18 as braking means.

  The output of the engine 3 is input to a front differential device 21 (hereinafter referred to as “front differential 21”) via a transmission 19 as a transmission. The front wheels 7 and 9 are linked to the front differential 21 via left and right axle shafts 23 and 25.

  A generator 27 as a power generator is provided on the engine 3 side. The generator 27 generates power in conjunction with the rotation of the engine 3.

The electric motor 5 is controlled by a controller 29 as control means. The electric motor 5 is configured as a drive source of the speed reduction drive device 31 and is powered by the generator 27 and driven. The output of the electric motor 5 is input to the speed reduction mechanism 33 of the speed reduction drive device 31. A rear differential device 35 (hereinafter referred to as “rear differential 35”) is input from the speed reduction mechanism 33. The left and right rear wheels 11 and 13 are linked to the rear differential 35 via left and right axle shafts 37 and 39. The left and right rear wheels 11 and 13 are provided with disc brakes 41 and 43 as braking means. The drive system path from the electric motor 5 to the rear wheels 11 and 13 is provided with an interrupting section for interrupting torque transmission. In this embodiment, torque is provided between the speed reduction mechanism 33 and the rear differential 35. A clutch 45 is provided as an interrupting portion for interrupting transmission. The clutch 45 is intermittently controlled to transmit torque by the controller 29.
[Control means]
The controller 29 as the control means includes an ECU (Electric Control Unit) 47 and a motor 4WD / ECU 49. The ECU 47 and the 4WD / ECU 47 construct a CAN (Community Area Network) and share information with each other. The ECU 47 may be a single ECU combined with the 4WD • ECU 47, or may be composed of a plurality of ECUs.

  The ECU 47 is, for example, an A / T shift signal that is a signal from the A / T shift sensor 50 of the transmission 19 as a vehicle information, a wheel speed signal from the wheel speed sensor 51, and an engine speed from the engine speed sensor 53. Signal, throttle opening signal from throttle opening sensor 55 of the accelerator, motor rotation speed signal from motor rotation speed sensor 57, brake signal from disc brakes 15, 17, 16, 18 and vehicle abnormality A fail signal, a TCS signal indicating whether or not a TCS (Traction Control System) controller is performing TCS control, and the like are input.

The motor 4WD / ECU 49 has a 4WD auto mode, a 4WD lock auto mode, and a 2WD mode as drive control modes. Each mode can be selected by operating the switch 59.
[Four wheel drive control]
In the four-wheel drive control, in the 4WD auto mode and the 4WD lock auto mode, torque assist or the like is performed by the rear wheels 11 and 13 when starting or when the front wheels 7 and 9 slip. In both the 4WD auto mode and the 4WD lock auto mode, the basic control is performed by driving the electric motor 5 in addition to the engine 3 in a predetermined low speed range from about 15 to 30 km / h from the start. To do. On the other hand, in the middle / high speed range, only the engine 3 is driven to be in a two-wheel drive state.
In addition to such basic control, the clutch 4 is engaged / disengaged by the motor 4WD / ECU 49 based on various signals as vehicle information input to the ECU 47 to automatically switch between the two-wheel drive state and the four-wheel drive state.

  That is, the 4WD auto mode is based on the A / T shift signal, wheel speed signal, engine speed signal, throttle opening signal, motor speed signal, ABS signal, fail signal, and TCS signal. The drive state is automatically switched and controlled.

  The switching control based on the throttle opening signal and the A / T shift signal is performed when the throttle opening reaches a predetermined value or when the shift position, which is a shift position, is 3 or more as a predetermined high speed stage. The driving state is set.

  The 4WD lock auto mode automatically switches between a two-wheel drive state and a four-wheel drive state according to a signal other than the throttle opening signal and the A / T shift signal, and the throttle opening signal and the A / T shift. Switching control between the two-wheel drive state and the four-wheel drive state based on the signal is restricted and the four-wheel drive state is set.

  The four-wheel drive control will be described with reference to FIGS. FIG. 2 is a flowchart showing an outline of drive mode control. FIG. 3 is a flowchart showing details of the 4WD auto mode. FIG. 4 is a flowchart showing details of the 4WD lock auto mode.

  As shown in FIG. 2, in the four-wheel drive control, vehicle data communication is performed in step S1. That is, an A / T shift signal, a wheel speed signal, an engine speed signal, a throttle opening signal, a motor speed signal, a brake signal, a fail signal, a TCS signal, and the like are input to the ECU 47. Thereby, the process of step S1 is completed, and the process proceeds to step S2.

  In step S2, the drive control mode is determined. That is, it is determined whether the drive control mode is selected as the 4WD auto mode, 4WD lock auto mode, or 2WD mode.

  If the 4WD auto mode is selected, the process proceeds to step S3. If the 4WD lock auto mode is selected, the process proceeds to step S4. If the 2WD mode is selected, the process proceeds to step S5. .

  In step S3, the 4WD auto mode is executed, and in step S4, the 4WD lock auto mode is executed. In step S5, the 2WD mode is executed, and the motor 4WD / ECU 49 causes the clutch 45 to be disconnected and the drive of the electric motor 5 to be stopped.

After each step S3 to S5 is completed, the process from step S1 is repeated.
[4WD auto mode]
The 4WD auto mode according to step S4 in FIG. 2 will be described with reference to FIG.

  As shown in FIG. 3, in the 4WD auto mode, various signals are read in step S11. That is, the motor 4WD / ECU 49 controls the ABS (Antilock Brake System) based on the A / T shift signal, wheel speed signal, engine speed signal, throttle opening signal, motor speed signal, brake signal, etc. The ECU 47 reads an ABS signal, a fail signal, and a TCS signal indicating whether or not the operation is performed. Thereby, the process of step S11 is completed, and the process proceeds to step S12.

  In step S12, the clutch 45 is determined to be disengaged based on the read signal. That is, whether or not the shift position has reached the third speed or more, whether or not the wheel speed, the engine speed, the throttle opening, the motor speed has reached a predetermined value, the presence or absence of an ABS signal, a fail signal, a TCS signal, etc. to decide. Then, based on the determination result, it is determined whether or not the clutch 45 is to be disconnected.

  When based on the throttle opening signal and the A / T shift signal, it is determined that the clutch is disengaged when the throttle opening reaches a predetermined value or when the shift position becomes the third speed or higher.

  If it is determined that the clutch is to be disconnected, the process proceeds to step S13. If it is determined that the clutch is not to be disconnected, the process proceeds to step S14.

  In step S13, the clutch 4 is disengaged by the motor 4WD / ECU 49. When the clutch 45 is disconnected, the torque transmission between the speed reduction mechanism 33 and the rear differential 35 is cut off. For this reason, transmission of the driving force of the electric motor 5 to the left and right rear wheels 11 and 13 is restricted, resulting in a two-wheel drive state with only the left and right front wheels 7 and 9. Thereby, the process of step S13 is completed, and the process from step S11 is repeated.

In step S14, the clutch 45 is fastened by the motor 4WD / ECU 49. Therefore, torque transmission is in a connected state between the speed reduction mechanism 33 and the rear differential 35, and the driving force of the electric motor 5 is transmitted from the speed reduction mechanism 33 to the clutch 45, the rear differential 35, and the left and right axle shafts 37, 39. To the left and right rear wheels 11 and 13. For this reason, the four-wheel drive state by the left and right front and rear wheels 7, 9, 11, 13 is achieved. Thereby, the process of step S14 is completed, and the process from step S11 is repeated.
[4WD lock auto mode]
The 4WD lock auto mode according to step S5 in FIG. 2 will be described with reference to FIG.

  As shown in FIG. 4, in the 4WD lock auto mode, a 4WD lock signal is input in step S21. That is, the 4WD lock signal output based on the selection of the switch 59 is input to the motor 4WD / ECU 49. Thereby, the process of step S21 is completed, and the process proceeds to step S22.

  In step S22, A / T shift regulation and throttle opening signal reading regulation are performed in accordance with the 4WD lock signal. That is, the motor 4WD / ECU 49 transmits a restriction signal for restricting the A / T shift from shifting to a high speed stage of 3rd speed or higher to the A / T shift side via the ECU 47. As a result, the A / T shift is limited so that it does not shift to the third speed or higher and shifts only to the second speed, which is the lower speed. In this case, the gear position can be set to the first speed.

  At the same time, the motor 4WD / ECU 49 is restricted from reading the accelerator opening signal in response to the 4WD lock signal, and the detected value of the accelerator opening is invalidated. Thereby, the process of step S22 is completed, and the process proceeds to step S23.

  In step S23, various signals are read. That is, the motor 4WD / ECU 49 sends an A / T shift signal, wheel speed signal, engine speed signal, motor speed signal, ABS signal, fail signal, and TCS signal other than the accelerator opening signal that is restricted from reading from the ECU 47. Read. Thereby, the process of step S21 is completed, and the process proceeds to step S24.

  In step S24, the clutch 45 is determined to be disengaged based on the read signal. That is, it is determined whether or not the engine speed, the wheel speed, and the motor speed have reached predetermined values, and the presence / absence of an ABS signal, a fail signal, and a TCS signal. Then, based on the determination result, it is determined whether or not the clutch 45 is to be disconnected.

  At this time, in the 4WD lock auto mode, the reading of the throttle opening signal is restricted and the A / T shift is restricted from shifting to a higher speed of 3rd speed or higher, and therefore based on the throttle opening and the shift position. The clutch disengagement decision is not made.

  When it is determined that the clutch is to be disconnected, the process proceeds to step S25, and when it is determined that the clutch is not to be disconnected, the process proceeds to step S26.

  In step S25, processing similar to that in step S13 in FIG. 3 is performed, and in step S26, processing similar to that in step S14 in FIG. 3 is performed. After both steps S25 and S26 are completed, the processing from step S21 is repeated.

  Therefore, in the 4WD lock auto mode, the two-wheel drive state and the four-wheel drive state are automatically switched and controlled according to signals other than the throttle opening signal and the A / T shift signal. Further, switching control from the four-wheel drive state to the two-wheel drive state by the throttle opening signal is regulated to maintain the four-wheel drive state.

  In the present embodiment, the four-wheel drive state is maintained except during braking or when the allowable rotational speed of the electric motor is exceeded.

For this reason, in the 4WD lock auto mode, when delicate accelerator control is performed at the time of traveling at an intersection, the vehicle does not change from the four-wheel drive state to the two-wheel drive state against the intention of the driver, and travels without a sense of incongruity. be able to. In addition, even if the accelerator is released during a freezing slope, the gear will not be shifted up to the third speed, and the vehicle will be driven with little or no sense of incongruity without changing from the four-wheel drive state to the two-wheel drive state. Can do.
[Effect of Example]
According to the present embodiment, in the 4WD lock auto mode, the two-wheel drive state and the four-wheel drive state are automatically switched and controlled according to the traveling state, and the four-wheel drive state to the two-wheel drive state based on the throttle opening information. It is possible to maintain the four-wheel drive state by restricting the switching control.

  Therefore, even when the two-wheel drive state and the four-wheel drive state are automatically switched by the 4WD lock auto mode, the four-wheel drive state can be reliably maintained.

  In the 4WD auto mode, the two-wheel drive state is set when the throttle opening becomes a predetermined value or when the shift position becomes the third speed or higher, which is a predetermined high speed stage. In the 4WD lock auto mode, the motor 4WD • ECU49 With this control, it is possible to invalidate the detected value of the throttle opening by restricting the reading of the throttle opening signal and to restrict the shift position to the third speed or higher and maintain the four-wheel drive state.

  For this reason, in this embodiment, the four-wheel drive state can be easily and reliably maintained.

  In the present embodiment, the auxiliary drive source that is intermittently switched to switch between the two-wheel drive state and the four-wheel drive state is the electric motor 5 that is driven by the generated power by the rotation of the engine 3, and the shift position is set in the 4WD lock auto mode. Is restricted to 3rd speed or higher.

  Therefore, in the present embodiment, it is possible to maintain the high speed of the engine 3 and reliably secure the power generation amount of the generator 27 in the 4WD lock auto mode. For this reason, the electric motor 5 can be driven reliably and the four-wheel drive state can be reliably maintained.

  More specifically, when the electric motor 5 is generally used as the sub drive source, the rotational speed of the engine 3 decreases and the power generation amount of the generator 27 decreases when the shift position reaches the third speed or higher. When the amount of power generation is reduced, it is not possible to secure electric power for driving the electric motor 5, and there is a possibility that the four-wheel drive state cannot be maintained.

  On the other hand, in this embodiment, as described above, the shift position is restricted to the third speed or higher so that the power generation amount of the generator 27 can be secured.

  Further, in this embodiment, since switching between the two-wheel drive state and the four-wheel drive state is performed by the engagement of the clutch 45 provided between the speed reduction mechanism 33 of the speed reduction drive device 31 and the rear differential 35, the switching is easy and It can be done reliably.

  As mentioned above, although the Example of this invention was described, this invention is not limited to this, The various design change accompanying the element of a structure is possible. For example, in the above embodiment, the throttle opening signal is invalidated and the shift position is restricted to the third speed, and the switching control between the two-wheel drive state and the four-wheel drive state is restricted. Both the signal and the shift position signal may be invalidated.

  In the above embodiment, the predetermined high speed stage is set to the third speed. However, for example, the low speed stage can be set to the first speed, and the high speed stage can be set to the second speed or the fourth speed.

It is a skeleton top view of a four-wheel drive vehicle to which a four-wheel drive control device is applied (Example). It is a flowchart which shows the outline of drive mode control (Example). It is a flowchart which shows the detail of 4WD auto mode (Example). It is a flowchart which shows the detail of 4WD lock auto mode (Example).

Explanation of symbols

1 Four-wheel drive vehicle 3 Engine (main drive source)
5 Electric motor (sub drive source)
7,9 Front wheel (main drive wheel)
11, 13 Rear wheel (sub drive wheel)
27 Generator 29 Controller (control means)
45 Clutch (intermittent part)
47 ECU
49 Motor 4WD / ECU
59 switch

Claims (5)

In a four-wheel drive control device that causes a control means to perform an auto mode for automatically switching control between a two-wheel drive state and a four-wheel drive state according to a running state grasped based on at least throttle opening information of the automobile,
The control means includes a lock auto mode,
Provide a switch that enables selection between the auto mode and the lock auto mode,
The lock auto mode, the throttle opening information by the four-wheel drive control unit according to claim regulate the switching control possible to maintain the four-wheel drive state from four-wheel drive state to a two-wheel drive state. The four-wheel drive control device according to claim 1,
A main drive source for driving the main drive wheel and a sub drive source for driving the sub drive wheel;
The four-wheel drive control device, wherein the control means switches between the two-wheel drive state and the four-wheel drive state by intermittently transmitting drive force from the auxiliary drive source. The four-wheel drive control device according to claim 2,
The main drive source is an engine;
The four-wheel drive control device, wherein the sub drive source is an electric motor that is driven by electric power generated by rotation of the engine. The four-wheel drive control device according to claim 3,
In the lock auto mode , when the switching control from the four-wheel drive state to the two-wheel drive state is regulated by the throttle opening information, the four-wheel drive state is maintained except during braking or when the allowable rotational speed of the electric motor is exceeded. A four-wheel drive control device. The four-wheel drive control device according to claim 3 or 4,
The four-wheel drive control device, wherein the control means sets the shift position to the first speed or the second speed in the four-wheel drive state in the lock auto mode.

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