JP4983309B2 - Vehicle driving force control device - Google Patents

Description

  The present invention relates to an apparatus for controlling a driving force transmitted to a wheel in a vehicle configured to shift a driving force generated by a driving source with a transmission and transmit the driving force to the wheel.

  In general, in a vehicle, a drive system component for transmitting a rotational driving force generated by a driving source such as an engine to a wheel, specifically, a drive shaft or a drive shaft joint (a hub for mounting a drive shaft and a wheel) The strength of the joints that connect the unit is sufficiently secured. However, for example, when sudden start or rapid acceleration is performed with the steering amount set to or close to the full steering state, such as a sudden turn or sudden start such as a spin turn, an excessive driving force (drive) Torque) may be input suddenly. In particular, in front engine / front drive (FF) type vehicles and 4WD type vehicles (especially FR-based 4WD), the left and right front wheels are the drive wheels and the steering wheels, so torque is applied to the left and right front wheels. The load applied to the drive system components that transmit the power increases.

  For example, as the drive shaft joint, for example, a Rzeppa type constant velocity joint (also called a barfield type constant velocity joint) as shown in FIG. 8 is used. The Rzeppa-type constant velocity joint 110 includes a plurality of (for example, six) balls 111, an inner cylinder member 112, an outer cylinder member 113, a cage 114, and the like, and a lubricant such as grease is contained therein. Is enclosed by a boot 115.

  The inner cylindrical member 112 is fitted and fixed to the outer periphery of the end portion of the drive shaft 120. The inner cylindrical member 112 is curved along the axial direction and in the axial direction at several circumferential positions on the outer diameter side (the same number as the balls 111). An outer curved groove 112a is provided. The outer cylinder member 113 is disposed on the outer diameter side of the inner cylinder member 112 and has a bottomed cylindrical shape. The outer cylinder member 113 has an axial direction at several circumferential positions (the same number as the balls 111) on the inner diameter side. An inner curved groove 113a that is curved along the axial direction is provided, and a shaft portion 113b that protrudes in the axial direction is provided at the center of the bottom. Then, between the outer curved groove 112a of the inner cylindrical member 112 and the inner curved groove 113a of the outer cylindrical member 113, the ball 111 held by the retainer 114 is correspondingly rollably interposed. . A shaft portion 113b extending from the outer cylinder member 113 is attached to a wheel mounting hub unit (not shown).

  If the joint angle of the constant velocity joint 110, that is, the angle formed by the drive shaft 120 and the shaft portion 113b of the outer cylinder member 113 changes depending on the vehicle state, the ball 111 and the outer curved groove 112a of the inner cylinder member 112 and the outer It moves along the inner curved groove 113a of the cylindrical member 113. As the joint angle of the constant velocity joint 110 increases, the ball 111 moves toward the open end side peripheral edge 113c of the inner curved groove 113a of the outer cylinder member 113 (the ball 111 positioned near the open end side peripheral edge 113c). Is indicated by an imaginary line).

  When transmission of driving torque is performed in a state where the joint angle of the constant velocity joint 110 is large, a load applied to the open end side peripheral edge 113c of the inner curved groove 113a of the outer cylindrical member 113 with which the ball 111 is in contact increases. Since the open end side peripheral portion 113c of the inner curved groove 113a of the outer cylinder member 113 is a relatively thin portion, it is preferable that an excessive load is not applied to the open end side peripheral portion 113c.

  By the way, the driving | running | working in the above vehicle states may not necessarily be performed by all the drivers, and some drivers may perform. Therefore, the strength of the drive system parts is ensured by assuming torque transmission in a vehicle state where the drive shaft joint angle is equal to or greater than a predetermined angle and the driver intends to start or accelerate suddenly. There is a need. Here, the strength of the drive system parts can be improved by increasing the size or replacing the material with a material having excellent strength, but this is disadvantageous in terms of vehicle motion performance and fuel consumption. There is a problem that the cost increases.

Patent Document 1 discloses a technique for preventing a sudden start of a vehicle in an oblique direction. When the steering amount is a predetermined amount or more at the time of start, the engine output is limited to start the vehicle. It is shown that the speed is controlled.
JP-A-11-334626

  However, the above Patent Document 1 only discloses that the engine output is limited to suppress the vehicle starting speed when the steering amount is greater than or equal to a predetermined amount at the time of starting. Nothing is said about ensuring the strength of drivetrain components such as joints.

  The present invention has been made in view of such points, and in a vehicle in which a driving force generated by a driving source is shifted by a transmission and transmitted to a wheel, driving system components such as a drive shaft and a drive shaft joint are provided. The purpose is to guarantee the strength of the.

In the present invention, means for solving the above-described problems are configured as follows. That is, the present invention is a vehicle driving force control device that shifts a driving force generated by a driving source with a transmission and transmits it to a wheel, and whether or not the drive shaft joint angle is a predetermined angle or more based on the vehicle state. When the joint angle determining means for determining whether or not the brake operation and the accelerator operation are performed at the same time, it is determined that the driver intends to start suddenly or accelerate rapidly. If the start or sudden acceleration determination means determines that there is no intention of start or rapid acceleration, and the drive shaft joint angle is equal to or greater than a predetermined angle and the driver has an intention of sudden start or rapid acceleration, It is characterized by comprising driving force suppressing means for suppressing the transmitted driving force.
Here, the presence or absence of the brake operation and the presence or absence of the accelerator operation are used as the determination factors as to whether the driver intends to suddenly start or accelerate. The driver intentionally suddenly starts or accelerates the vehicle. This is because the brake pedal and the accelerator pedal are depressed simultaneously. That is, if the accelerator pedal is further depressed while the brake pedal is depressed, and the brake pedal is suddenly released in this state, the vehicle can be suddenly started or accelerated.

  Here, the drive source means at least one of an engine and a motor (including a motor generator). The drive shaft joint is a constant velocity joint used to connect the drive shaft and a wheel mounting hub unit. The joint angle is an angle formed by the drive shaft connected by the constant velocity joint and a shaft member (a shaft portion extending from the outer cylinder member of the constant velocity joint) attached to the hub unit for mounting the drive wheel. .

  According to the above configuration, in a vehicle state where the drive shaft joint angle is equal to or greater than the predetermined angle and the driver intends to start or accelerate suddenly, the drive source is driven through the transmission, drive shaft, etc. Since the driving force (driving torque) transmitted to the wheels is suppressed, it is possible to avoid sudden start or sudden acceleration in such a vehicle state. And the torque transmitted to drive system components can be reduced. Therefore, the load applied to the drive system component can be reduced, and damage to the drive system component is difficult to accumulate. Therefore, the durability of the drive system component can be improved, and the strength of the drive system component can be guaranteed. . In this case, it is possible to ensure sufficient strength of the drive system component without increasing the size of the drive system component or replacing the material of the drive system component with a material having excellent strength. Cost can also be reduced.

  In the present invention, examples of the specific configuration of the joint angle determination means include the following configuration. That is, the joint angle determining means can be configured to determine that the drive shaft joint angle is equal to or greater than a predetermined angle when the vehicle height is equal to or greater than a predetermined value and the steering amount is equal to or greater than the predetermined amount. It is.

  The reason why the vehicle height is used as a determination factor as to whether or not the joint angle is greater than or equal to the predetermined angle is that the joint angle changes as the vehicle height changes depending on the number of passengers in the vehicle. In this case, with the exception of an empty vehicle state, the vehicle height is the highest in the case of a single passenger and the joint angle is the largest in the actual vehicle. For this reason, with the vehicle height as one of the determination factors, it is determined whether or not the vehicle height is the highest or close to the vehicle height, in other words, whether or not the vehicle height is a predetermined value or more.

  The reason why the steering amount is used as a determination factor as to whether or not the joint angle is greater than or equal to a predetermined angle is that the joint angle changes depending on the steering amount of the steering wheel. In this case, when the steering amount of the steering wheel is the maximum, the joint angle is the largest. For this reason, with the steering amount as one of the determination factors, it is determined whether or not the full steering state or a state close thereto, in other words, whether or not the steering amount is equal to or greater than a predetermined amount.

  Next, in the present invention, examples of the specific configuration of the driving force suppressing means include the following four forms.

  First, there is a form that suppresses the output torque of the engine.

  Second, when the vehicle is configured to decelerate the rotational power generated by the engine with a stepped automatic transmission and transmit it to the wheels, the gear stage of the stepped automatic transmission is changed. In the control map based on the accelerator opening or throttle opening of the vehicle and the vehicle speed, which is referred to at the time, the shift line from the 1st speed to the 2nd speed (shift stage switching line) is changed to the low vehicle speed side. It is done.

  Third, when the vehicle is configured to decelerate the rotational power generated by the engine with a continuously variable automatic transmission and transmit it to the wheels, the transmission ratio of the continuously variable automatic transmission is increased. The form which changes to the speed side is mentioned.

  Fourth, when the vehicle is configured to transmit the rotational driving force generated by at least one of the engine and the motor (including a motor generator) to the wheels by decelerating with the transmission, the motor A form that suppresses output is mentioned.

  According to the present invention, in a vehicle state where the drive shaft joint angle is equal to or larger than a predetermined angle and the driver intends to start or accelerate suddenly, the drive source is driven through the transmission, the drive shaft, and the like. Since the driving force (driving torque) transmitted to the wheels is suppressed, it is possible to avoid sudden start or sudden acceleration in such a vehicle state. And the torque transmitted to drive system components can be reduced. Therefore, damage is less likely to accumulate in the drive system component, so that the durability of the drive system component can be improved and the strength of the drive system component can be guaranteed.

  The best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  Hereinafter, an embodiment in which the present invention is applied to a front engine / front drive (FF) type vehicle will be described. Moreover, the case where the output torque of the engine is suppressed will be described as an example as a mode of suppressing the driving force (drive torque) transmitted to the wheels.

[Schematic configuration of vehicle]
First, a schematic configuration of a vehicle according to the embodiment will be described with reference to FIG.

  In the vehicle 1 shown in FIG. 1, a rotational driving force generated by an engine 2 as a drive source is appropriately shifted by an automatic transmission (transaxle) 3 and left and right drive shafts 4L and 4R are passed through left and right drive shafts 4L and 4R. It is configured to be transmitted to the front wheels 6FL, 6FR. Thus, the left and right front wheels 6FL, 6FR are provided as drive wheels. The automatic transmission 3 includes a torque converter, a planetary gear type transmission mechanism that sets a gear stage by a clutch, a brake, a planetary gear device, and the like, and a differential mechanism. In the automatic transmission 3, it is necessary to refer to a control map (shift map; see, for example, FIG. 7) stored in advance in the transmission control device 90 based on the accelerator opening (or throttle opening) and the vehicle speed. The gear position (gear) is determined, and the transmission control device 90 controls, for example, a hydraulic control device or the like, thereby performing a gear shift operation (change of gear step).

  Here, the left drive shaft 4L and the left front wheel 6FL are connected via a Zepper type constant velocity joint 5L (specifically, refer to FIG. 8). Specifically, the drive shaft 4L and the hub unit for mounting the front wheel 6FL are connected by the Zepper type constant velocity joint 5L. Similarly, the right drive shaft 4R and the right front wheel 6FR are also connected via a Rzeppa constant velocity joint 5R. On the other hand, the left and right rear wheels 6RL, 6RR are driven wheels and are connected to each other by a rear axle shaft (not shown).

  The left and right front wheels 6FL and 6FR are provided as steering wheels. That is, the left and right front wheels 6FL and 6FR are configured to rotate in the steering direction according to the steering amount (rotation angle) when the driver steers the steering wheel 43 installed in the vehicle 1. ing. Such a steering mechanism is configured as a so-called electric power steering mechanism including, for example, an assisting electric motor 16 and a speed reduction mechanism 17. Specifically, the assist electric motor 16 is for applying an assist force to the steering of the left and right front wheels 6FL and 6FR by the steering wheel 43. The assisting electric motor 16 is attached to the steering shaft 18 connected to the steering wheel 43 via the speed reduction mechanism 17 so as to be able to transmit torque, and the rack bar 19 is driven in the axial direction in accordance with the rotation thereof. The left and right front wheels 6FL, 6FR connected to the rack bar 19 via tie rods (not shown) are steered.

  The left and right front wheels 6FL and 6FR are provided with front brakes 7FL and 7FR, and the left and right rear wheels 6RL and 6RR are provided with rear brakes 7RL and 7RR, respectively. These front brakes 7FL and 7FR and rear brakes 7RL and 7RR are configured as so-called disc brakes, for example. Specifically, the front, rear, left and right brakes 7FL, 7FR, 7RL, and 7RR each include a disc rotor 8 and a brake caliper 9. The brake caliper 9 holds a pair of left and right brake pads (not shown) disposed on both side surfaces of the disc rotor 8.

  These brakes 7FL, 7FR, 7RL, 7RR are actuated when the driver depresses a brake pedal 42 installed in the vehicle 1. Specifically, the driver's stepping force on the brake pedal 42 is transmitted to the actuator 12 for driving the brake caliper 9 via the power transmission unit 13. The actuator 12 is used to increase or decrease the operation of the brakes 7FL, 7FR, 7RL, 7RR, that is, the hydraulic pressure (brake hydraulic pressure) with respect to the brake caliper 9. The power transmission unit 13 is for driving the actuator 12 in accordance with the depressing operation force of the brake pedal 42, and includes a negative pressure booster 14 and a master cylinder 15. The negative pressure booster 14 applies a force such as a negative pressure or compressed air of the engine 2 to the stepping operation force according to the stepping operation force of the brake pedal 42, thereby reducing the stepping operation force of the brake pedal 42. It will increase the power. The master cylinder 15 converts the depressing operation force of the brake pedal 42 into the brake hydraulic pressure supplied from the actuator 12 to the brake caliper 9.

[Engine and engine control device]
Next, an example of the engine 2 will be briefly described with reference to FIG.

  The engine 2 illustrated in FIG. 2 includes an air that is introduced from an intake system and an intake port 22a and an injector 25 into a combustion chamber 24 defined by a cylinder 21a of a cylinder block 21, a cylinder head (not shown), and a piston 23. An air-fuel mixture in which fuel to be injected is mixed at a predetermined ratio is supplied, and the air-fuel mixture is ignited and burned by spark discharge of the spark plug 26, thereby rotating the crankshaft 28 via the piston 23 and the connecting rod 27. Thus, the driving force (engine torque) of the engine 2 is output. The exhaust gas after combustion in the combustion chamber 24 is discharged from the exhaust port 22b to the exhaust system. The intake system is provided in the middle of the intake passage 37, an air cleaner (not shown) provided upstream of the intake passage 37 connected to the intake port 22a, and is opened and closed by a depression operation of the accelerator pedal 41 by the driver. A throttle valve 29 to be driven is included.

  The cylinder head 22 is provided with an intake valve 31 for opening and closing the intake port 22a and an exhaust valve 32 for opening and closing the exhaust port 22b. The intake valve 31 is opened / closed by the intake side camshaft 33 and the exhaust valve 32 is opened / closed by the exhaust side camshaft 34. The intake side camshaft 33 and the exhaust side camshaft 34 are rotationally driven by a crankshaft 28 via a timing chain (or timing belt) (not shown).

  The engine control device 80 for controlling the operation of the engine 2 is connected to a transmission control device 90 for controlling the operation of the automatic transmission 3 so that necessary information can be transmitted and received. Both control devices 80 and 90 are generally configured as well-known ECUs (electronic control devices). Here, only the engine control device 80 related to this embodiment will be described with reference to FIG.

  The engine control device 80 adjusts the engine speed and the engine torque by controlling the operation of the engine 2 based on various information inputs. For example, as shown in FIG. 3, a central processing unit (CPU) 81 is used. A read-only memory (ROM) 82, a random access memory (RAM) 83, a backup RAM 84, an input interface 85, and an output interface 86 are connected to each other via a bidirectional bus 87. It has become.

  The CPU 81 executes arithmetic processing based on an appropriate control program or control map stored in the ROM 82. The ROM 82 stores at least a control program related to basic engine control. The RAM 83 is a memory that temporarily stores calculation results in the CPU 81, data input from various sensors, and the like. The backup RAM 84 is a non-volatile memory that stores various data to be saved.

[Characteristics of Embodiment]
Next, the characteristic part of this embodiment will be described in detail with reference to FIGS.

  In this embodiment, when the joint angles of the constant velocity joints 5L and 5R (hereinafter also simply referred to as “joint angles”) are large and the driver tries to perform an operation such as a sudden start, the front wheels 6FL and 6FR The device is designed to suppress the transmitted driving force (driving torque). Here, the joint angle of the constant velocity joint 5L is a shaft member (an outer cylinder member of the constant velocity joint 5L) that is connected to the drive shaft 4L and the hub unit for mounting the front wheel 6FL, which are connected by the constant velocity joint 5L. (The same is true for the joint angle of the constant velocity joint 5R).

  Specifically, as shown in FIG. 3, the input interface 85 of the engine control device 80 includes various sensors (for example, a water temperature sensor 61, an air flow meter 62, an intake air temperature sensor 63, an accelerator position, which are necessary for basic engine control. Sensor 64, throttle position sensor 65, crank position sensor 66, intake cam position sensor 67, exhaust cam position sensor 68, etc.), at least wheel speed sensors 71a-71d, brake switch 72, steering angle sensor 73, vehicle High sensors 74L and 74R, an input shaft rotational speed sensor 76, an output shaft rotational speed sensor 77, and the like are connected.

  The output interface 86 includes, for example, an injector 25, an igniter 35 for ignition of the ignition plug 26, a throttle motor 36 for opening / closing driving of the throttle valve 29, and the like as various components necessary for basic engine control. It is connected.

  The accelerator position sensor 64 is attached to the accelerator pedal 41 and detects the amount of depression of the accelerator pedal 41 by the driver. Based on the detection output from the accelerator position sensor 64, it is possible to determine whether or not the driver has depressed the accelerator pedal 41 and to recognize the amount of depression (accelerator opening). Here, the presence or absence of the depression operation of the accelerator pedal 41 by the driver can be determined based on whether or not the depression operation amount is equal to or greater than a predetermined value (threshold value) set in advance.

  The wheel speed sensors 71a to 71d detect wheel speeds of the front wheels 6FL and 6FR and the rear wheels 6RL and 6RR, respectively. Based on the detection outputs from the wheel speed sensors 71a to 71d, the wheel speeds of the front wheels 6FL and 6FR and the rear wheels 6RL and 6RR are recognized, and the vehicle body speed of the vehicle 1 (based on the recognized wheel speeds ( Vehicle speed) and the like can be calculated.

  The brake switch 72 is attached to the brake pedal 42, and detects whether or not the driver has depressed the brake pedal 42. Based on the detection output from the brake switch 72, it is possible to determine whether or not the driver has depressed the brake pedal 42.

  The steering angle sensor 73 detects the steering torque of the steering shaft 18 connected to the steering wheel 43. Based on the detection output from the steering angle sensor 73, it is possible to calculate the steering amount (steering angle) of the steering wheel 43 leftward or rightward by the driver.

  The vehicle height sensors 74L and 74R are provided, for example, between a suspension member that supports the front wheels 6FL and 6FR and the vehicle body, respectively, and the heights (distances from the road surface) of these vehicle height sensors 74L and 74R are provided. Is detected. Based on detection outputs from these vehicle height sensors 74L and 74R, the vehicle height of the vehicle 1 can be calculated (for example, an average value). For example, the vehicle height sensors 74L and 74R can be configured to measure the distance from the road surface using a detection wave such as an ultrasonic wave or a laser beam. The vehicle height sensor may be configured to detect the inclination angle of the vehicle body of the vehicle 1 with respect to the axle portion (drive shafts 4L, 4R). Moreover, it is good also as a structure which provides a vehicle height sensor in each of front-wheel 6FL, 6FR and rear-wheel 6RL, 6RR.

  The input shaft rotational speed sensor 76 and the output shaft rotational speed sensor 77 detect the rotational speed of the input shaft and the rotational speed of the output shaft of the automatic transmission 3, respectively. Based on the detected outputs from the input shaft rotational speed sensor 76 and the output shaft rotational speed sensor 77, the ratio of the rotational speed of the input shaft and the rotational speed of the output shaft of the automatic transmission 3 (output shaft rotational speed / input shaft rotational speed). Number) can be calculated, and the current gear stage (gear stage) of the automatic transmission 3 can be estimated based on the ratio of the rotational speeds.

[Operation of engine control unit]
Next, the operation of the engine control device 80 will be described with reference to the flowchart of FIG. The routine shown in FIG. 4 is a part of the main routine related to engine control executed by the engine control device 80, and is repeated at regular intervals.

  First, in step ST11, the engine control device 80 determines whether or not the vehicle speed is equal to or lower than a predetermined speed. This determination can be made based on detection outputs from the wheel speed sensors 71a to 71d. If the vehicle speed exceeds the predetermined speed, there is no possibility of corresponding to a sudden start or acceleration as described below, so the following processing is omitted and this routine is terminated. On the other hand, when the vehicle speed is equal to or lower than the predetermined speed, there is a possibility of corresponding to a sudden start or a rapid acceleration as described below, and the process proceeds to the next step ST12. In step ST11, “below the predetermined speed” means that the vehicle 1 is stopped and includes a state where the vehicle 1 is swinging back and forth.

  Next, in steps ST12 and ST13, the engine control device 80 determines whether or not the joint angle is greater than or equal to a predetermined angle from the vehicle state. In this embodiment, the vehicle height (step ST12) and the steering amount (step ST13) are adopted as determination elements for determining whether or not the joint angle is equal to or greater than a predetermined angle.

  Specifically, in step ST12, the engine control device 80 determines whether or not the vehicle height is greater than or equal to a predetermined value. This determination can be made based on the detection outputs from the vehicle height sensors 74L and 74R. If the vehicle height is below a predetermined value, this routine is terminated. On the other hand, if the vehicle height is greater than or equal to the predetermined value, the process proceeds to the next step ST13.

  Thus, the reason why the vehicle height is used as a determination factor as to whether or not the joint angle is greater than or equal to a predetermined angle is that the joint angle changes as the vehicle height changes depending on the number of passengers of the vehicle 1 and the like. . In this case, with the exception of an empty vehicle state, the vehicle height is the highest in the case of a single passenger and the joint angle is the largest in the actual vehicle. For this reason, with the vehicle height as one of the determination factors, it is determined whether or not the vehicle height is the highest or close to the vehicle height, in other words, whether or not the vehicle height is a predetermined value or more.

  In step ST13, the engine control device 80 determines whether or not the steering amount of the steering wheel 43 is equal to or greater than a predetermined amount. This determination can be made based on the detection output from the steering angle sensor 73. Then, when the steering amount of the steering wheel 43 is less than the predetermined amount, this routine is ended. On the other hand, when the steering amount of the steering wheel 43 is equal to or larger than the predetermined amount, the engine control device 80 determines that the joint angle is equal to or larger than the predetermined angle (step ST14).

  The reason why the steering amount is used as a determination factor as to whether or not the joint angle is equal to or greater than the predetermined angle is that the joint angle changes depending on the steering amount of the steering wheel 43. In this case, when the steering amount of the steering wheel 43 is the maximum, the joint angle becomes the largest. For this reason, with the steering amount as one of the determination factors, it is determined whether or not the full steering state or a state close thereto, in other words, whether or not the steering amount is equal to or greater than a predetermined amount.

  As described above, when the vehicle height is equal to or greater than a predetermined value and the steering amount of the steering wheel 43 is equal to or greater than a predetermined amount, it is determined that the joint angle is equal to or greater than the predetermined angle.

  Next, in step ST15, the engine control device 80 determines whether or not the current gear position of the automatic transmission 3 is the first speed. This determination can be made based on detection outputs from the input shaft rotational speed sensor 76 and the output shaft rotational speed sensor 77. If the gear position of the automatic transmission 3 is not the first speed, this routine is terminated. On the other hand, when the gear position of the automatic transmission 3 is the first speed, the routine proceeds to the next step ST16.

  As described above, the shift speed of the automatic transmission 3 is confirmed by the driving force (drive torque) transmitted to the front wheels 6FL and 6FR via the drive shafts 4L and 4R by the shift speed of the automatic transmission 3. Because it changes. In this case, when the shift stage of the automatic transmission 3 is the first speed, the transmission torque is the largest. For this reason, it is determined whether or not the gear position of the automatic transmission 3 is the first speed.

  Next, in steps ST16 and ST17, the engine control device 80 determines whether the driver has an intention of sudden start or rapid acceleration based on the vehicle state. In this embodiment, the presence / absence of a brake operation (step ST16) and the presence / absence of an accelerator operation (step ST17) are adopted as determination factors as to whether or not the driver intends to start suddenly or accelerate.

  Specifically, in step ST16, the engine control device 80 determines whether or not the driver has depressed the brake pedal 42. This determination can be made based on the detection output from the brake switch 72. If the driver does not depress the brake pedal 42, this routine is terminated. On the other hand, when the driver depresses the brake pedal 42, the process proceeds to the next step ST17.

  In step ST17, the engine control device 80 determines whether or not the driver has depressed the accelerator pedal 41. This determination can be made based on the detection output from the accelerator position sensor 64. If the driver does not depress the accelerator pedal 41, this routine is terminated. On the other hand, when the driver depresses the accelerator pedal 41, the engine control device 80 determines that the driver has an intention of sudden start or rapid acceleration (step ST18).

  As described above, the presence or absence of the brake operation and the presence or absence of the accelerator operation are used as the determination factors as to whether or not the driver intends to start suddenly or accelerate suddenly. This is because the brake pedal 42 and the accelerator pedal 41 are simultaneously depressed when accelerating. That is, if the accelerator pedal 41 is further depressed in a state where the brake pedal 42 is depressed, and the brake pedal 42 is suddenly released in this state, the vehicle 1 can be suddenly started or accelerated.

  As described above, when the driver depresses the brake pedal 42 and the accelerator pedal 41 simultaneously, it is determined that the driver has an intention of sudden start or rapid acceleration.

  In step ST19, the engine control device 80 executes control for suppressing the output torque of the engine 2 to a predetermined value or less. The output torque of the engine 2 can be suppressed, for example, by controlling the opening of the throttle valve 29 to a predetermined value or less with the throttle motor 36.

  As a result, in a vehicle state where the joint angle is equal to or greater than the predetermined angle and the driver intends to start or accelerate suddenly, the front wheel is transmitted from the engine 2 via the automatic transmission 3, the drive shafts 4L, 4R, and the like. The driving force (driving torque) transmitted to 6FL and 6FR is suppressed to a predetermined value or less, and as a result, sudden start or sudden acceleration of the vehicle 1 in such a vehicle state can be avoided. Then, the torque transmitted to the drive system components can be reduced to a predetermined value or less. Therefore, the load applied to the drive system component can be reduced, and damage to the drive system component is difficult to accumulate. Therefore, the durability of the drive system component can be improved, and the strength of the drive system component can be guaranteed. . Further, it is advantageous for improving the running performance of the vehicle 1.

  And in this case, it becomes possible to ensure sufficient strength of the drive system parts without increasing the size of the drive system parts or replacing the materials of the drive system parts with those having excellent strength. In addition, the cost can be reduced. Here, the predetermined value of the torque transmitted to the drive system component is a value that can sufficiently ensure the strength of the drive system component, and is obtained empirically by performing experiments and calculations in advance. Further, the predetermined value of the output torque of the engine 2 and the predetermined value of the opening degree of the throttle valve 29 are set to such values that a predetermined value of torque transmitted to such drive system components can be obtained.

  By the way, the vehicle height sensors 74L and 74R and the steering angle sensor 73 of this embodiment and the processing functions of steps ST12 and ST13 by the engine control device 80 correspond to the joint angle determination means described in claim 1. In addition, the brake switch 72 and the accelerator position sensor 64 of this embodiment and the processing functions of steps ST16 and ST17 by the engine control device 80 correspond to the sudden start determination means described in claim 1. Further, the processing function of step ST19 by the engine control device 80 of this embodiment corresponds to the driving force suppressing means according to claim 1. Therefore, in this embodiment, the engine control device 80 corresponds to the driving force control device according to the present invention.

[Modification]
The embodiment of the present invention has been described above. However, the embodiment shown here is an example and can be variously modified. An example is given below.

  (1) In the above embodiment, the type of vehicle using only the engine as a drive source has been described as an example. However, a hybrid vehicle using a combination of an engine and a motor (including a motor generator) as a drive source may be used. Is possible. That is, the vehicle can be configured such that the rotational driving force generated by at least one of the engine and the motor can be decelerated by the transmission and transmitted to the wheels.

  (2) In the above embodiment, the FF type vehicle is taken as an example. However, the vehicle is not particularly limited as long as the left and right front wheels are driving wheels and steering wheels. For example, a 4WD vehicle can be used.

  (3) In the above embodiment, it is determined in step ST11 of FIG. 4 whether or not the vehicle speed is equal to or lower than a predetermined speed. Instead of this determination, whether or not the vehicle is in a stopped state, that is, the vehicle speed is You may make it determine whether it is "0". If the vehicle is in a stopped state, the gear position of the automatic transmission is determined to be the first speed. In this case, the determination in step ST15 in FIG. 4 can be omitted.

  (4) In the above embodiment, a stepped automatic transmission was taken as an example, but as a transmission, a belt type continuously variable transmission (CVT) capable of adjusting a gear ratio steplessly is mounted on a vehicle. It is good also as composition to do. In the case of CVT, in step ST15, based on the detection outputs from the input shaft speed sensor 76 and the output shaft speed sensor 77, the CVT gear ratio (input shaft speed / output shaft speed) is preset. It is determined whether or not it is in the range (Low range).

  In addition, an SMT (Sequential Manual Transmission) that performs clutch engagement / disengagement operation and transmission transmission operation through a hydraulic control device or the like may be mounted on the vehicle.

  (5) In the above embodiment, the case where the output torque of the engine is suppressed is taken as an example of the mode for suppressing the driving force (drive torque) transmitted to the wheels, but other modes may be adopted. .

  (5-1) For example, a control map (shift map) based on the accelerator opening (or throttle opening) of the vehicle and the vehicle speed, which is referred to at the time of the shift operation (change of the shift stage) of the stepped automatic transmission. ), The driving force (driving torque) transmitted to the wheels may be suppressed by changing the shift line from the first speed to the second speed (shift line for shifting stage) to the low vehicle speed side. In this case, since the driving force suppression control is performed not on the engine (drive source side) but on the automatic transmission side, the control subject is not the engine control device but the transmission control device as shown in FIG. 90 ′ is preferable.

  Here, the specific configuration of the transmission control device 90 ′ will be described. The transmission control device 90 ′ controls the operation of the automatic transmission by controlling the operation of the automatic transmission through, for example, the hydraulic control device 98 based on various information inputs. It adjusts the stage, etc., and is connected to an engine control device that controls the operation of the engine so that necessary information can be transmitted and received. Then, for example, as shown in FIG. 5, the transmission control device 90 ′ includes a central processing unit (CPU) 91, a read only memory (ROM) 92, a random access memory (RAM) 93, a backup RAM 94, and an input. The interface 95 and the output interface 96 are connected to each other via a bidirectional bus 97.

  The CPU 91 executes arithmetic processing based on an appropriate control program or control map stored in the ROM 92. The ROM 92 stores at least a control program related to basic shift control and the shift map described above. The RAM 93 is a memory that temporarily stores calculation results in the CPU 91, data input from various sensors, and the like. The backup RAM 94 is a non-volatile memory that stores various data to be saved. The input interface 95 includes various sensors necessary for basic shift control (for example, an accelerator position sensor 64, a throttle position sensor 65, a crank position sensor 66, an input shaft rotational speed sensor 76, an output shaft rotational speed sensor 77, In addition to the shift position sensor 78 and the like, at least wheel speed sensors 71a to 71d, a brake switch 72, a steering angle sensor 73, vehicle height sensors 74L and 74R, and the like are connected. At least an automatic transmission hydraulic control device 98 is connected to the output interface 96.

  A driving force suppression control routine executed by the transmission control device 90 'is shown in the flowchart of FIG. The routine shown in FIG. 6 is a part of the main routine related to the shift control executed by the transmission control device 90 ', and is repeated at regular intervals.

  In FIG. 6, the processes of steps ST21 to ST28 executed by the transmission control device 90 'are the same as the processes of steps ST11 to ST18 executed by the engine control device 80 shown in FIG. By these steps ST21 to ST28, when the joint angle is equal to or larger than the predetermined angle and the driver has an intention of sudden start or rapid acceleration, the process proceeds to step ST29 (corresponding to step ST19 in FIG. 4).

  Then, in step ST29, as shown in FIG. 7, the shift line from the first speed to the second speed of the shift stage of the automatic transmission is changed (shifted) by a predetermined amount to the low vehicle speed side. In FIG. 7, only the shift line when upshifting from the first speed to the second speed in the shift map of the automatic transmission is shown, and the shift line when performing the driving force suppression control is indicated by a solid line, and the driving force suppression control is illustrated. A shift line in a normal case where no operation is performed is indicated by a broken line. In this way, the first gear is quickly shifted up to the second gear, and accordingly, the driving torque transmitted from the automatic transmission to the front wheels via the drive shaft or the like is quickly suppressed. Become. Then, the torque transmitted to the drive system components can be quickly reduced below a predetermined value.

  In this case, the vehicle height sensors 74L and 74R, the steering angle sensor 73, and the processing functions of steps ST22 and ST23 performed by the transmission control device 90 'correspond to the joint angle determination means described in claim 1. Further, the brake switch 72, the accelerator position sensor 64, and the processing functions of steps ST26 and ST27 by the transmission control device 90 'correspond to the sudden start determination means described in claim 1. Further, the processing function of step ST29 by the transmission control device 90 'corresponds to the driving force suppressing means described in claim 1. In this case, the transmission control device 90 'corresponds to the driving force control device according to the present invention.

  (5-2) Also, for example, when the automatic transmission is the CVT of (4) above, the CVT transmission ratio is changed to the upshift side (acceleration side) by a predetermined amount to be transmitted to the wheels. The driving force (driving torque) may be suppressed. By so doing, the drive torque transmitted from the CVT to the front wheels via the drive shaft or the like is quickly suppressed as the CVT gear ratio is changed to the upshift side. Also in this case, as in the case described above, the driving force suppression control is performed not on the engine (drive source side) but on the CVT side (transmission side). Instead, it is preferable to use a transmission control device. The specific configuration of the transmission control device can be substantially the same as that of the above (5-1) (see FIG. 5). Note that the change of the CVT gear ratio can be performed through a hydraulic control device. In this case, the hydraulic control device can be controlled by a transmission control device.

  (5-3) Further, for example, when the vehicle is the hybrid vehicle of (1), the driving force (driving torque) transmitted to the wheels is suppressed by suppressing the output of the motor to a predetermined value or less. It is good also as a simple structure. In this case, since the driving force suppression control is performed on the driving source side, the control subject can be the engine control device similar to that in the above embodiment.

1 is a diagram illustrating an overall configuration of a vehicle according to an embodiment. It is a schematic block diagram which shows an engine control apparatus typically. It is a block diagram which shows schematic structure of an engine control apparatus. It is a flowchart which shows an example of operation | movement of an engine control apparatus. It is a block diagram which shows schematic structure of a transmission control apparatus. It is a flowchart which shows an example of operation | movement of a transmission control apparatus. It is a figure which shows the shift map of an automatic transmission, and shows the change (only at the time of upshift from 1st speed to 2nd speed) of the shift line of an automatic transmission. It is a figure which shows the drive shaft joint for demonstrating the specific example of the conventional problem.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Engine 3 Automatic transmission 4L, 4R Drive shaft 5L, 5R Constant velocity joint 6FL, 6FR Front wheel 6RL, 6RR Rear wheel 7FL, 7FR Front brake 7RL, 7RR Rear brake 29 Throttle valve 36 Throttle motor 41 Accelerator pedal 42 Brake pedal 43 Steering wheel 64 Accelerator position sensor 71a-71d Wheel speed sensor 72 Brake switch 73 Steering angle sensor 74L, 74R Vehicle height sensor 76 Input shaft rotational speed sensor 77 Output shaft rotational speed sensor 80 Engine control device 90 Transmission control device

Claims (6)

A driving force control device for a vehicle configured to shift a driving force generated by a driving source with a transmission and transmit the driving force to a wheel,
A joint angle judging means for judging whether or not the drive shaft joint angle is a predetermined angle or more from the vehicle state;
When the brake operation and the accelerator operation are performed at the same time, it is determined that the driver has an intention of sudden start or acceleration, and at other times the driver has no intention of sudden start or rapid acceleration A means for determining sudden start, etc.
When the drive shaft joint angle is equal to or greater than a predetermined angle and the driver intends to suddenly start or accelerate, driving force suppression means is provided that suppresses the driving force transmitted to the wheel. A vehicle driving force control device. The vehicle driving force control apparatus according to claim 1,
The joint angle determining means determines that the drive shaft joint angle is greater than or equal to a predetermined angle when the vehicle height is greater than or equal to a predetermined value and the steering amount is greater than or equal to a predetermined amount. Driving force control device. In the vehicle driving force control device according to claim 1 or 2 ,
A driving force control device for a vehicle, wherein the driving force transmitted to the wheels is suppressed by suppressing an output torque of the engine. In the vehicle driving force control device according to claim 1 or 2 ,
The vehicle is configured to decelerate the rotational power generated by the engine with a stepped automatic transmission and transmit it to the wheels,
The shift line from the first speed to the second speed in the control map based on the accelerator opening or throttle opening of the vehicle and the vehicle speed, which is referred to when changing the gear position of the stepped automatic transmission, is set to the low vehicle speed side. The driving force control device for a vehicle is configured to suppress the driving force transmitted to the wheels by changing to the above. In the vehicle driving force control device according to claim 1 or 2 ,
The vehicle is configured to decelerate the rotational power generated by the engine with a continuously variable automatic transmission and transmit it to the wheels,
A driving force control apparatus for a vehicle, wherein the driving force transmitted to the wheels is suppressed by changing a gear ratio of the continuously variable automatic transmission to a speed increasing side. In the vehicle driving force control device according to claim 1 or 2 ,
The vehicle is configured to decelerate a rotational driving force generated by at least one of an engine and a motor with a transmission and transmit the rotational driving force to wheels.
A driving force control device for a vehicle, wherein the driving force transmitted to the wheels is suppressed by suppressing the output of the motor.

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