Vehicle control device

Abstract

Provided is a vehicle control device capable of effectively suppressing wheel spin of a drive wheel by reducing a time lag of traction control.　A vehicle control device (20) includes a slip ratio detection rate means (22) for detecting a slip ratio of a drive wheel (WR) of a vehicle (1), and supplies braking hydraulic pressure to a braking device (9) of the drive wheel (WR) when the slip ratio exceeds a threshold value. The vehicle control device (20) supplies minute preload to the braking device (9), and supplies braking hydraulic pressure higher than the preload to brake the drive wheel (WR) when the slip ratio exceeds the threshold value. The vehicle control device (20) repeatedly supplies and stops the minute preload when supplying the minute preload.

Description

Vehicle control device

[0001] The present invention relates to a vehicle control device, and particularly to a vehicle control device that can effectively suppress wheel spin of drive wheels of a vehicle.

[0002] Conventionally, a vehicle control device that suppresses wheel spin of drive wheels by operating a braking device of the drive wheels of a vehicle is known.

[0003] Patent Document 1 discloses a vehicle control device that suppresses wheel spin of drive wheels by operating a braking device of the rear wheels to ensure traction when the slip ratio of the rear wheels of a motorcycle exceeds a threshold value.

[0004] Japanese Unexamined Patent Application Publication No. 2020-142357

[0005] However, for example, when automatically controlling a disk brake system that operates by hydraulic pressure, if there is an extra gap, in other words, an ineffective stroke, between the hydraulic piston of the brake caliper and the brake pad, a time lag occurs from when an operation command is given to a hydraulic modulator that supplies braking hydraulic pressure until a predetermined braking force is generated, and there is a problem that the effect of traction control is reduced.

[0006] An object of the present invention is to solve the above problems of the prior art and provide a vehicle control device that can reduce the time lag of traction control and effectively suppress wheel spin of drive wheels.

[0007] To achieve the above object, the present invention has slip ratio detection means (22) for detecting the slip ratio of drive wheels (WR) of a vehicle (1), and in a vehicle control device (20) that supplies braking hydraulic pressure to a braking device (9) of the drive wheels (WR) when the slip ratio exceeds a threshold value, the vehicle control device (20) supplies a minute pre-pressure to the braking device (9), and when the slip ratio exceeds the threshold value, supplies a braking hydraulic pressure higher than the pre-pressure to brake the drive wheels (WR), which is the first feature.

[0008] Further, the vehicle control device (20) has a second feature in that when supplying the minute pre-pressure, the supply and stop are repeated.

[0009] Furthermore, the vehicle control device (20) has a third feature in that it changes the magnitude of the brake hydraulic pressure supplied when the slip ratio exceeds a threshold, and the period until the supply of the brake hydraulic pressure is stopped, according to the behavior of the vehicle (1).

[0010] Furthermore, the fourth characteristic is that the drive wheel (WR) is the rear wheel of the vehicle (1), and the behavior of the vehicle (1) is an indicator related to the stroke of the rear cushion (8) that supports the rear wheel (WR).

[0011] Furthermore, a fifth feature is that the supply of the preload is triggered by the detection of the vehicle (1) starting.

[0012] According to the first feature, in a vehicle control device (20) having a slip ratio detection means (22) for detecting the slip ratio of the drive wheels (WR) of a vehicle (1), and supplying braking hydraulic pressure to a braking device (9) of the drive wheels (WR) when the slip ratio exceeds a threshold, the vehicle control device (20) supplies a small amount of preload to the braking device (9), and when the slip ratio exceeds the threshold, supplies braking hydraulic pressure higher than the preload to brake the drive wheels (WR). By supplying a small amount of preload in advance, the ineffective stroke of the braking device can be reduced. As a result, by activating the braking device when the slip ratio exceeds the threshold, the time lag between the start of control and the generation of a predetermined hydraulic pressure in the braking device can be reduced, and torque control to suppress wheel spin can be executed with high accuracy.

[0013] According to the second feature, the vehicle control device (20) repeatedly supplies and stops the minute preload, thereby making it possible to avoid a state in which the friction material of the braking device is in contact, so-called brake drag.

[0014] According to the third feature, the vehicle control device (20) changes the magnitude of the brake hydraulic pressure supplied when the slip ratio exceeds a threshold, and the period until the supply of the brake hydraulic pressure is stopped, according to the behavior of the vehicle (1), thereby enabling the supply of appropriate brake hydraulic pressure according to the behavior of the vehicle.

[0015] According to the fourth feature, the drive wheel (WR) is the rear wheel of the vehicle (1), and the behavior of the vehicle (1) is an indicator related to the stroke of the rear cushion (8) that supports the rear wheel (WR), so it is possible to supply appropriate braking hydraulic pressure in relation to the behavior of the vehicle body.

[0016] According to the fifth feature, since the supply of the preload is triggered by the detection of the vehicle (1) starting, it is possible to efficiently suppress slippage that occurs when starting on slippery road surfaces, etc.

[0017] This is a right side view of a motorcycle to which a vehicle control device according to one embodiment of the present invention is applied. This is a block diagram showing the vehicle control device and its surrounding configuration. This is a flowchart showing the procedure for rear wheel slip suppression control. This is a time chart showing the manner of hydraulic pressure supplied to the rear brake caliper. This is a block diagram showing the configuration of a vehicle control device according to a second embodiment of the present invention.

[0018] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 is a right side view of a motorcycle 1 to which a vehicle control device 20 according to one embodiment of the present invention is applied. The motorcycle 1 is a saddle-type vehicle to which the rotational power of a power unit P, which is an integrated internal combustion engine and transmission, is transmitted to the rear wheel WR via a drive chain 10.

[0019] A head pipe F1 is fixed to the front ends of a pair of left and right main frames F2 that make up the vehicle frame F, pivotally supporting a steering stem (not shown). A top bridge 5 and a bottom bridge 4 are fixed above and below the steering stem, supporting a pair of left and right front forks 2. The front wheel WF is pivotally supported at the lower end of the front forks, and a front fender 3 covering the upper part of the front wheel WF is attached to the lower part of the bottom bridge 4. A steering handle 6 is attached to the upper part of the top bridge 5. A fuel tank 7 is located behind the head pipe F1. A rear frame F3 supporting a seat 17 and a rear fender 15 is connected to the rear of the main frame F2.

[0020] A pivot frame F4 is connected to the lower rear of the main frame F2, supporting a pivot 12 that pivotally supports the swingarm 11. The swingarm 10 that pivotally supports the rear wheel WR is suspended from the vehicle frame F by a rear cushion 8. The power unit P is supported between the main frame F2 and pivot frame F4 and an under frame F5 that extends downward from the rear of the head pipe F1. The combustion gases of the power unit P are discharged through the exhaust pipe 14 and out of a muffler 16 located behind the rear cushion 8.

[0021] The rear wheel WR is equipped with a hydraulic rear brake caliper 9, which acts as a braking device to brake the brake disc. A brake pedal 13 for the driver to operate the rear brake caliper 9 is pivotally supported on the pivot plate F4 on the right side in the vehicle width direction. Meanwhile, the motorcycle 1 is equipped with a hydraulic modulator 30 controlled by a vehicle control device 20. The hydraulic modulator 30 is configured to supply hydraulic pressure to the rear brake caliper 9 in response to various sensor signals, regardless of the driver's operation of the brake pedal 13. A front wheel rotation speed sensor 41 is located near the rotation axis of the front wheel WF to detect the rotation speed of the front wheel WF, and a rear wheel rotation speed sensor 42 is located near the rotation axis of the rear wheel WF to detect the rotation speed of the rear wheel WR.

[0022] Figure 2 is a block diagram showing the vehicle control device 20 and its surrounding configuration. The same reference numerals indicate the same or equivalent parts. The vehicle control device 20 includes a starting detection means 21 that detects when the motorcycle 1 has started moving, a rear wheel slip ratio detection means 22 that detects the slip ratio of the rear wheel WR, a rear brake caliper control means 23 that arbitrarily operates the hydraulic brake system of the rear wheel WR, and a power unit torque suppression means 26 that appropriately reduces the output of the power unit P. The rear brake caliper control means 23 has an ineffective stroke reduction portion 24 and a slip suppression portion 25.

[0023] The vehicle control device 20 receives signals from a throttle opening sensor 61 that detects the opening of the throttle valve that adjusts the output of the power unit P, a clutch sensor 62 that detects the clutch engagement state, a front wheel rotation speed sensor 41 that detects the rotation speed of the front wheel WF, a rear wheel rotation speed sensor 42 that detects the rotation speed of the rear wheel WR, a power unit rotation speed sensor 63 that detects the rotation speed of the power unit P, and a rear cushion stroke sensor 18 that detects the stroke amount of the rear cushion 8.

[0024] The rear brake caliper control means 30 operates a hydraulic modulator 30 in response to various sensor signals to supply hydraulic pressure to the rear brake caliper 9. The dead stroke reduction unit 24 performs dead stroke reduction control to reduce the dead stroke, which is the excess gap between the hydraulic piston and brake pad of the rear brake caliper 9. The slip suppression unit 25, assuming that the dead stroke reduction control has been performed, supplies braking hydraulic pressure to the rear brake caliper 9 when the slip ratio of the rear wheel WR exceeds a threshold to suppress the slip of the rear wheel WR. The power unit torque suppression means 26 controls the output of the power unit P in response to various sensor signals.

[0025] Figure 3 is a flowchart showing the procedure for rear wheel slip suppression control. In step S1, the starting detection means 21 determines whether or not the vehicle has started moving. If the determination in step S1 is positive, the process proceeds to step S2, where the invalid stroke reduction unit 24 performs invalid stroke reduction control, which supplies a small amount of force to the rear brake caliper 9. On the other hand, if the determination in step S1 is negative, the process returns to the determination in step S1.

[0026] In the following step S3, it is determined whether the slip ratio of the rear wheel WR detected by the rear wheel slip ratio detection means 22 exceeds a threshold. If the determination in step S3 is positive, the process proceeds to step S4, where the slip suppression unit 25 supplies braking hydraulic pressure to the rear brake caliper 9 to suppress the slip of the rear wheel WR. On the other hand, if the determination in step S3 is negative, the process returns to the determination in step S3.

[0027] In step S5, the supply mode of the brake hydraulic pressure is changed according to the body behavior of the motorcycle 1. The body behavior is detected, for example, based on the stroke amount and reciprocating motion of the rear cushion 8. In the following step S6, it is determined whether the rear wheel slip ratio has fallen below a threshold. If the determination is positive, the process proceeds to step S7, where the supply of brake hydraulic pressure is terminated, and the series of control operations ends. On the other hand, if the determination in step S6 is negative, the process returns to step S5.

[0028] Figure 4 is a time chart showing the configuration of hydraulic pressure supplied to the rear brake caliper 9. In this time chart, the solid line shows the hydraulic pressure Pa supplied to the rear brake caliper 9 by the rear wheel slip suppression control according to this embodiment, and the dashed line shows the hydraulic pressure Pb supplied to the rear brake caliper 9 by the conventional rear wheel slip suppression control. When the rear brake caliper control means 23 detects that the motorcycle 1 has started moving at time 0 (zero), it starts the ineffective stroke reduction control. In this embodiment, the ineffective stroke reduction control is configured to repeatedly supply and stop minute amounts of preload (A1, A2, A3). This ineffective stroke reduction control makes it possible to avoid a state in which the brake pads are in contact with the brake disc, so-called brake drag.

[0029] At time t1, the maximum value of the supplied hydraulic pressure by the rear wheel slip suppression control, which is initiated when the rear wheel slip ratio exceeds a threshold, is detected. On the other hand, in conventional rear wheel slip suppression control, the maximum value of the supplied hydraulic pressure is detected at time t2, and it can be seen that the time from the start of control to the generation of a predetermined hydraulic pressure is shortened by the ineffective stroke reduction control according to this embodiment. In this embodiment, preload is supplied along a sine wave, but preload may also be supplied along a square wave. The magnitude of the minute preload is set to a value that provides high responsiveness within a range that does not cause rear brake drag. In addition, the period for supplying preload can be set to a period that does not cause the hydraulic pressure to rise too high.

[0030] In this embodiment, the vehicle control device 20 supplies a small amount of preload to the rear brake caliper 9, and when the slip ratio exceeds a threshold, it supplies a braking hydraulic pressure higher than the preload to brake the rear wheel WR. By supplying a small amount of preload in advance, the ineffective stroke of the rear brake caliper 9 can be reduced. As a result, by activating the rear brake caliper 9 when the slip ratio exceeds a threshold, the time lag between giving an activation command to the hydraulic modulator 30 and generating a predetermined braking force can be reduced, and torque control to suppress wheel spin can be executed with precision.

[0031] Furthermore, the vehicle control device 20 changes the magnitude of the brake hydraulic pressure supplied when the slip ratio exceeds a threshold, and the period until the supply of brake hydraulic pressure is stopped, according to the behavior of the motorcycle 1. This makes it possible to supply appropriate brake hydraulic pressure according to the behavior of the motorcycle 1. In addition, the vehicle control device 20 changes the magnitude of the brake hydraulic pressure and the period until the supply is stopped according to an indicator related to the stroke of the rear cushion 8, such as the stroke amount and the manner of reciprocating motion, so that it can supply appropriate brake hydraulic pressure in relation to the behavior of the vehicle body. Furthermore, since the supply of preload is triggered by the detection of the motorcycle 1 starting, it is possible to efficiently suppress slip that occurs when starting on slippery road surfaces, etc. The rear wheel slip suppression control by the rear brake caliper 9 described above can be used in combination with control that suppresses the torque of the power unit by the power unit torque suppression means.

[0032] Figure 5 is a block diagram showing the configuration of a vehicle control device 60 according to a second embodiment of the present invention. The same reference numerals indicate the same or equivalent parts. The vehicle control device 60 includes a jump detection means 27 for detecting when the motorcycle 1 has jumped, a landing detection means 28 for detecting when the motorcycle 1 has landed after the jump, a rear wheel slip ratio detection means 22, a rear brake caliper control means 23, and a pressure amount map 50 that determines the hydraulic pressure supplied to the rear brake caliper 9 based on various conditions. The rear brake caliper control means 23 has an ineffective stroke reduction section 24 and a slip suppression section 25. The pressure amount map 50 also includes a stroke speed-pressure amount map 51 and a Δwheel speed-pressure amount map 52.

[0033] The vehicle control device 60 receives signals from a throttle opening sensor 61, a clutch sensor 62, a front wheel rotation speed sensor 41, a rear wheel rotation speed sensor 42, a power unit rotation speed sensor 63, a rear cushion stroke sensor 18, and a gyro sensor 19 that detects the vehicle's posture and acceleration.

[0034] The rear brake caliper control means 23 operates the hydraulic modulator 30 in response to various sensor signals to supply hydraulic pressure to the rear brake caliper 9. The dead stroke reduction unit 24 performs dead stroke reduction control to reduce the dead stroke, which is the excess gap between the hydraulic piston and brake pad of the rear brake caliper 9. The slip suppression unit 25, assuming that the dead stroke reduction control has been performed, supplies braking hydraulic pressure to the rear brake caliper 9 to suppress slip of the rear wheel WR when the slip ratio of the rear wheel WR exceeds a threshold.

[0035] The vehicle control device 60 according to this embodiment is capable of suppressing excessive slip of the rear wheel WR that occurs when the motorcycle 1 lands after a jump. By suppressing slip during landing, it is possible to prevent the vehicle's behavior from becoming unstable due to skidding or the rear wheel suddenly gripping. In addition, the vehicle control device 60 can also suppress wheelies during landing by supplying a predetermined hydraulic pressure to the rear brake caliper 9 while the motorcycle 1 is jumping, thereby generating an inertial force that lowers the front of the vehicle.

[0036] In the control described above, the hydraulic pressure supplied to the rear brake caliper 90 is derived from the stroke speed-pressure amount map 51 and the delta-wheel speed-pressure amount map 52. The stroke speed-pressure amount map 51 is set so that the amount of pressure increases as the stroke speed of the rear cushion 8 increases. The delta-wheel speed-pressure amount map 52 is set so that the amount of pressure increases as the slip ratio, which is determined from the delta-wheel speed of the rear wheel WR, increases. These maps are pre-set based on the phenomenon that when the stroke speed of the rear cushion is small upon landing after a jump, the traction of the rear wheel WR increases due to a large vertical load or a large coefficient of friction of the road surface, and when the stroke speed of the rear cushion is large upon landing after a jump, the traction of the rear wheel WR decreases due to a small vertical load or a small coefficient of friction of the road surface.

[0037] The motorcycle's configuration, the power unit's configuration, the shape and structure of the rear brake caliper and hydraulic modulator, the type and number of sensors, and the vehicle control device's configuration are not limited to the above embodiments and can be modified in various ways. The vehicle control device according to the present invention is not limited to motorcycles but can be applied to various vehicles such as three-wheeled and four-wheeled vehicles.

[0038] 1...Motorcycle (vehicle), 9...Rear brake caliper (braking device), 20...Vehicle control device, 21...Starting detection means, 22...Rear wheel slip ratio detection means, 23...Rear brake caliper control means, 24...Ineffective stroke reduction part, 25...Slip suppression part, 30...Hydraulic modulator, A1, A2, A3...Small preload, WR...Rear wheel (drive wheel)

Claims

1. A vehicle control device (20) having a slip ratio detection means (22) for detecting the slip ratio of the drive wheels (WR) of a vehicle (1), and supplying braking hydraulic pressure to a braking device (9) of the drive wheels (WR) when the slip ratio exceeds a threshold, wherein the vehicle control device (20) supplies a small amount of preload to the braking device (9), and when the slip ratio exceeds a threshold, supplies braking hydraulic pressure higher than the preload to brake the drive wheels (WR).

2. The vehicle control device (20) is characterized in that it repeatedly supplies and stops the minute preload when supplying it, as described in claim 1.

3. The vehicle control device according to claim 1 or 2, characterized in that the vehicle control device (20) changes the magnitude of the brake hydraulic pressure supplied when the slip ratio exceeds a threshold, and the period until the supply of the brake hydraulic pressure is stopped, according to the behavior of the vehicle (1).

4. The vehicle control device according to claim 3, characterized in that the drive wheel (WR) is the rear wheel of the vehicle (1), and the behavior of the vehicle (1) is an indicator relating to the stroke of the rear cushion (8) that supports the rear wheel (WR).

5. The vehicle control device according to claim 1 or 2, characterized in that the supply of the preload is triggered by the detection of the vehicle (1) starting.

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