JP2903803B2 - Hydroplane detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydroplane detecting apparatus for detecting a hydroplane state generated by a water film between a tire and a road surface during running.

[0002]

2. Description of the Related Art Conventionally, as this type of hydroplane detection apparatus, for example, an apparatus described in Japanese Patent Application Laid-Open No. Sho 60-60463 is known.

[0003] This conventional source discloses a technique for detecting a hydroplane state when the deceleration of a driven wheel speed sensor value is large at a high vehicle speed in a traction control system using both a throttle and a brake.

When the hydroplane state is detected, it is determined that the vehicle is in the slip state in relation to the driving wheel speed, and traction control is performed. This is not a true acceleration slip but a pseudo slip. Because there is
Brake control is prohibited as a measure against hydroplanes.

[0005]

However, in such a conventional hydroplane detecting device, since the hydroplane state is detected only by the deceleration of the driven wheel speed sensor value, the driven wheel speed sensor is used. Only a short section from the entry of the hydroplane where the deceleration of the value is abrupt is a detection section of the hydroplane state, but thereafter, a section where the deceleration of the driven wheel speed sensor value becomes gentle below the reference value Is a non-detection section despite being in the hydroplane state. This is because the driven wheel speed characteristics when entering the hydroplane show a rapid deceleration of -5 G or more due to the water film resistance at the time of entry, and thereafter, the deceleration becomes gradual as the water film resistance weakens. Is shown. Further, the reference value of the deceleration cannot be set to a small value in order to prevent erroneous detection when the driven wheel speed is reduced other than in the hydroplane.

Further, in order to detect the instantaneous occurrence of hydroplay in the conventional apparatus, a high-speed calculation is required. In this case, for example, when the vehicle is running on a rough road over a bump, a road disturbance may occur. If the following wheel speed sensor value suddenly decelerates instantaneously, it is erroneously detected as the hydroplane state.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. In a hydroplane detecting apparatus for detecting a hydroplane state generated by a water film between a tire and a road surface during running, the present invention provides a hydroplane detection apparatus. A first object is to accurately detect a hydroplane state over almost the entire area from entry to exit during entry.

Further, in addition to the first problem, the followability between the driven wheel speed sensor value and the driven wheel speed filter value is improved, and the driven wheel speed filter value can be used for judging the acceleration / deceleration slip state. Doing so is a second problem.

[0009]

According to a first aspect of the present invention, there is provided a hydroplane detecting apparatus, comprising:
The difference between the driven wheel speed filter value and the driven wheel speed sensor value is calculated, and when the difference is equal to or larger than a predetermined value, the hydroplane state is detected.

That is, as shown in the claim correspondence diagram of FIG. 1, a driven wheel speed sensor a for detecting a driven wheel speed and a low pass filter having a predetermined cut-off frequency are applied to the driven wheel speed sensor value. Driven wheel speed filter value generating means b for generating a filter value, calculating a difference between the driven wheel speed filter value and the driven wheel speed sensor value, and detecting that the vehicle is in the hydroplane state when the difference is equal to or greater than a predetermined value. And a hydroplane detecting means c.

In order to solve the second problem, in the hydroplane detecting apparatus according to the second aspect, a low-pass filter is applied to the driven wheel speed sensor value, and an upper limit value is provided for the change amounts on the acceleration side and the deceleration side. This is a means for creating a driven wheel speed filter value.

That is, as shown in the claim correspondence diagram of FIG. 1, a driven wheel speed sensor a for detecting a driven wheel speed, a low pass filter having a predetermined cutoff frequency is applied to the driven wheel speed sensor value, And a driven wheel speed filter value generating means b ′ for generating a driven wheel speed filter value by setting an upper limit value for the amount of change on the deceleration side, and calculating a difference between the driven wheel speed filter value and the driven wheel speed sensor value. And a hydroplane detecting means c for detecting a hydroplane state when the difference is equal to or greater than a predetermined value.

[0013]

The operation of the first aspect of the present invention will be described.

If a hydroplane condition occurs during traveling, the hydroplane detecting means c outputs the driven wheel speed filter value generated by the driven wheel speed filter value generating means b and the driven wheel speed from the driven wheel speed sensor a. A difference from the speed sensor value is calculated, and if the difference is equal to or greater than a predetermined value, it is detected that the vehicle is in the hydroplane state.

That is, the value of the driven wheel speed sensor from the driven wheel speed sensor a shows a characteristic that when the vehicle enters the hydroplane state, the driven wheel rapidly decelerates due to water film resistance, and thereafter the degree of deceleration becomes gentle. On the other hand, driven wheel speed filter value creation means b
The driven wheel speed filter value created by (1) shows a characteristic in which the deceleration is gentler than the driven wheel speed sensor value by applying a low-pass filter having a predetermined cutoff frequency to the driven wheel speed sensor value.

Therefore, the difference between the driven wheel speed filter value and the driven wheel speed sensor value appears over almost the entire area from entry to exit when entering the hydroplane state, and the hydroplane state is detected with high accuracy. Is done.

Also, for example, even when a road surface disturbance enters the vehicle and the driven wheel speed sensor value suddenly decelerates instantaneously when driving on a rough road or the like, the difference between the driven wheel speed filter value from which the high-frequency component has been cut off is a predetermined value. The hydroplane state is not detected as long as the condition is not exceeded.

The operation of the invention according to claim 2 will be described.

In the driven wheel speed filter value creating means b ', a low pass filter having a predetermined cutoff frequency is applied to the driven wheel speed sensor value, and an upper limit value is provided for the amount of change on the acceleration side and the deceleration side to set the driven wheel speed filter value. A fast filter value is created.

Therefore, when the driven wheel speed filter value is an acceleration change amount exceeding the upper limit value, the acceleration side upper limit value of the driven wheel speed filter value is effective, and deceleration is performed when the driven wheel speed filter value exceeds the upper limit value. In the case of the change amount, the deceleration-side upper limit value of the driven wheel speed filter value is effective. For example, if the driven wheel speed sensor value changes in the order of acceleration → deceleration → acceleration → deceleration... The sensor value and the driven wheel speed filter value do not greatly separate from each other, and the responsiveness of both values is improved.When this driven wheel speed filter value is used to determine the acceleration / deceleration slip state, the acceleration / deceleration slip state Will be fairly evaluated.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration will be described.

FIG. 2 is an overall view of a braking / drive system control system for a rear wheel drive vehicle to which the hydroplane detection device according to the embodiment of the present invention is applied.

This rear-wheel drive vehicle has a throttle control for controlling a motor throttle opening degree so that a rear wheel slip ratio is within an optimum allowable range when an acceleration slip occurs, and is independent for right and left rear wheels when an acceleration slip occurs. In addition to a traction control system that is used in combination with a brake control that applies a braking force, an anti-skid brake control system that performs front and rear wheel brake fluid pressure control to prevent wheel lock during deceleration slip is mounted. Centralized electronic control of these systems is performed by a traction control system & anti-skid brake control system electronic control unit TCS / ABS-ECU (hereinafter abbreviated as TCS / ABS-ECU).

The TCS / ABS-ECU has a right front wheel speed sensor 1
Right front wheel speed sensor value VWF from (equivalent to driven wheel speed sensor)
R, a front left wheel speed sensor value VWFL from a front left wheel speed sensor 2 (corresponding to a driven wheel speed sensor), a rear right wheel speed sensor value VWRR from a rear right wheel speed sensor 3, and a rear wheel speed sensor 4 Left side wheel speed sensor value VWRL, the lateral acceleration sensor value YG from the lateral acceleration sensor 5, and the switch signal from the TCS switch 6.
SWTC and switch signal from brake lamp switch 7
Throttle 1 actual opening DKV from SWST and throttle control module TCM (hereinafter abbreviated as TCM)
And the automatic transmission control unit A /
Gear position signal and shift-up signal from TC / U (hereinafter abbreviated as A / TC / U) and engine rotation from ECCS C / U (hereinafter abbreviated as ECCS C / U) A number signal, a second throttle signal TVO2 from the second throttle sensor 17, and the like are input.

Then, the acceleration slip is detected from the TCS / ABS-ECU and the throttle 2 as a throttle opening / closing signal is detected.
The target opening DKR is output to the TCM, and a solenoid signal as a brake pressure increase / decrease signal is output to each solenoid valve of the common hydraulic unit TCS / ABS-HU (hereinafter abbreviated as TCS / ABS-HU). (Traction control combined with throttle and brake). Also, a deceleration slip is detected, and a solenoid signal as a brake pressure increase / decrease signal is output to TCS /
Output to each solenoid valve of ABS-HU (anti-skid brake control).

In addition to the above output, the TCS / ABS-ECU outputs a lighting command to the TCS fail lamp 14 when the TCS fails, and outputs a lighting command to the TCS operating lamp 15 during the TCS operation.

The TCM is a control circuit mainly including a throttle motor driving circuit. The TCM receives a first throttle signal TVO1 from the first throttle sensor 16 and outputs it to the TCS / ABS-ECU as a throttle 1 actual opening degree DKV. Or input the second throttle signal TVO2 from the second throttle sensor 17 as feedback information to the throttle 2 target opening DKR, or input the throttle 2 target opening DK from the TCS / ABS-ECU.
A motor drive current IM is applied to the throttle motor 18 based on R.

Here, the first throttle valve 19 provided with the first throttle sensor 16 is connected to the accelerator pedal 2.
The second throttle valve 21 provided with the second throttle sensor 17 is provided in the engine intake passage 22 in series with the first throttle valve 19, and is opened / closed by the throttle motor 18. Valve.

The traction control system includes an air flow meter AFM as a peripheral system as shown in FIG.
And an ECCS C / U and an injector, and an engine centralized electronic control system that performs centralized control of fuel injection control, ignition timing control, idle speed correction, etc., is installed. When the ON signal is input, control (select low control) for selecting a smaller valve opening degree of the first throttle signal TVO1 and the second throttle signal TVO2 is performed for transient characteristic correction, and the canister control and the EGR control are performed. Aborted.

Further, as shown in the figure, an automatic transmission control system having an A / TC / U and a shift solenoid and performing a shift control, a lock-up control and the like is mounted as a peripheral system as shown in FIG. , The gear position signal and the shift-up signal are taken into the TCS / ABS-ECU.

Further, as a peripheral system, as shown, a constant speed traveling control system having an ASCD actuator and performing automatic vehicle speed control so as to maintain a set vehicle speed is mounted. When the ON signal of the traction switch signal TCS SW is input, the opening control of the first throttle valve 19 is stopped, and when the OFF signal of the TCS SW is input, the return speed of the first throttle valve 19 is reduced.

FIG. 3 is a hydraulic circuit diagram showing a brake fluid pressure control system commonly used for traction brake control and anti-skid brake control independent of the left and right rear wheels.

This brake fluid pressure control system comprises a brake pedal 27, a hydraulic booster 28, a master cylinder 30 having a reservoir 29, wheel cylinders 31, 32,
33, 34, shared hydraulic unit TCS / ABS-HU
, Pump unit PU, and first accumulator unit
AU1, second accumulator unit AU2, front wheel side damping unit FDPU, rear wheel side damping unit RD
With PU.

The TCS / ABS-HU has a first switching valve 35a.
, A second switching valve 35b, and a left front wheel pressure increasing valve 36a.
, A right front wheel pressure increasing valve 36b and a left rear wheel pressure increasing valve 36
c, right rear wheel pressure increasing valve 36d, left front wheel pressure reducing valve 3
7a, a right front wheel pressure reducing valve 37b, a left rear wheel pressure reducing valve 37c, a right rear wheel pressure reducing valve 37c, a front wheel side reservoir 38a, a rear wheel side reservoir 38b, and a front wheel side pump 39.
a, a rear wheel side pump 39b, and a front wheel side damper chamber 40a.
And a rear-wheel-side damper chamber 40b and a pump motor 41.

At the time of normal braking or anti-skid brake control, the two switching valves 35a and 35b are set to the OFF position as shown in the figure to introduce the hydraulic pressure from the master cylinder 30, and during traction brake control (traction control). At the time of brake control).
In order to introduce the hydraulic pressure from the accumulator unit AU2, both switching valves 35a and 35b are set to the ON position. For example, in the pressure increase mode in the traction brake control, both control valves 36c, 36d, 37c, 37d are used.
Are set to the OFF position as shown in the figure, only the pressure increasing valves 36c, 36d are set to the ON position in the holding mode, and both control valves 36c, 36d, 37c, 37d are set in the pressure reducing mode.
Is set to the ON position, and the brake fluid from the wheel cylinders 33 and 34 is stored in the rear wheel side reservoir 38b.
The rotation of the rear wheel side pump 39b causes the rear wheel side damper chamber 40 to rotate.
b.

The first accumulator unit AU1 comprises:
The second accumulator unit AU2 is used as a hydraulic pressure source for the traction brake control, and both units AU1 and AU2 are connected to the reservoir 29.
A predetermined accumulator pressure is maintained by a common pump unit PU that sucks brake fluid from the pump.

The front-wheel-side damping unit FDPU and the rear-wheel-side damping unit RDPU are provided with a shared hydraulic unit TCS / AB in order to improve pedal feeling.
The influence of the fluid pressure change in the S-HU on the master cylinder 30 is suppressed.

The operation will be described.

(A) Normal Traction Control Operation FIG. 4 is a control block diagram showing the outline of the traction control performed by the TCS / ABS-ECU. The traction control logic can be roughly divided into the following four types of control.

(1) Calculation of Actual Slip State Filter processing is performed on the signals of the wheel speed sensors 1, 2, 3, and 4, and based on the wheel speed values after the filter processing, the actual slip state (slip amount, slip amount difference value) is calculated. ) Is calculated.

(2) Calculation of Target Slip State Filter processing is performed on the signal of the lateral acceleration sensor 5 to determine a turning / straight running based on lateral acceleration and to calculate a target slip state suitable for the running state based on the vehicle speed.

(3) Brake control A required brake increasing / decreasing speed (control duty ratio) is calculated by comparing the actual slip state with the target slip state, and is output to the TCS / ABS-HU.

(4) Throttle control Necessary throttle opening and opening / closing speed are calculated by comparing the actual slip state with the target slip state and output to the TCM.

The characteristics of this control logic are as follows:
In order to secure the limit detectability (steering force, skill sound, etc.) based on the base chassis performance according to each road surface condition that leads to active safety and to obtain active safety, the allowable slip state according to the magnitude of the lateral acceleration, The division of throttle / brake control is decided.

Further, in order to ensure stability during shifting and to improve controllability at each gear position, throttle / brake control according to the gear position is performed.

Further, in order to realize smooth acceleration feeling and controllability while suppressing slip hunting, and to realize engine torque increase / decrease control with good response, optimal throttle control according to the engine speed is performed.

(B) Hydroplane detection operation FIG. 5 is a flowchart showing a flow of a hydroplane detection processing operation performed in the TCS / ABS-ECU. Each step will be described below.

In step 50, the right front wheel speed sensor value VWFR from the right front wheel speed sensor 1 and the left front wheel speed sensor value VWFL from the left front wheel speed sensor 2 are filtered by a low-pass filter having a predetermined cutoff frequency. The front wheel speed filter value FVWFR and the left front wheel speed filter value FVWFL are used (corresponding to the driven wheel speed filter value generating means of claim 1).

In step 51, the right front wheel speed filter value F
The control right front wheel speed filter value VFTFR and the control front left wheel speed filter value VFTFL are respectively created by setting upper limits for the amounts of change on the acceleration side and the deceleration side in VWFR and the left front wheel speed filter value FVWFL. Described below).

That is, at the time of acceleration slip, when the right front wheel speed filter value FVWFR or the left front wheel speed filter value FVWFL is smaller than the larger value of the left and right rear wheel speeds VWRR and VWRL as the drive wheel speeds, as shown in FIG. , 10msec on the acceleration side
(10msec processing cycle) After holding, the maximum slope is regulated to + 0.4G, and on the deceleration side, 10msec is held for 2sec for -0.
Decelerate by 1G and then limit the slope to a maximum of -0.35G.

If the right front wheel speed filter value FVWFR or the left front wheel speed filter value FWWFL is greater than the larger one of the left and right rear wheel speeds VWRR and VWRL during a deceleration slip,
As shown in FIG. 7, the inclination is restricted to a maximum of -1.13G on the deceleration side.

In step 52, a high pre-flag HYPF indicating whether or not the hydroplane is in effect is set to HYPF = 1.
(Hydroplane state) is determined.

When HYPF = 0, the routine proceeds to step 53, where the difference between the control front right wheel speed filter value VFTFR and the front right wheel speed sensor value VWFR is equal to or greater than a set value V0 (for example, 5 km / h) and It is determined whether the difference between the front left wheel speed filter value VFTFL and the front left wheel speed sensor value VWFL is equal to or greater than the set value V0.

When the condition of step 53 is satisfied, the routine proceeds to step 54, where the high pre-flag HYPF is set to HYPF = 1 indicating the hydroplane state (steps 53 and 54 correspond to the hydroplane detecting means in claims). .

On the other hand, if YES is determined in the step 52, the process proceeds to a step 55 in which the difference between the control right front wheel speed filter value VFTFR and the right front wheel speed sensor value VWFR is set to a set value V1.
(For example, 2 km / h) and it is determined whether or not the difference between the control front left wheel speed filter value VFTFL and the front left wheel speed sensor value VWFL is smaller than the set value V1.

When the condition is satisfied in step 55, the process proceeds to step 56, where the high pre-flag HYPF is cleared to HYPF = 0, assuming that it has exited the hydroplane state.

If the vehicle enters the hydroplane state during traveling, step 50 → step 51 → step 52
→ The flow proceeds to step 53 → step 54. When the high pre-flag HYPF = 1 is set and the state of the hydroplane is exited, step 50 → step 51
The flow proceeds from step 52 to step 55 to step 56, and the high pre-flag HYPF = 0 is cleared.

That is, when entering the hydroplane state,
The front wheel speed sensor values of the left and right front wheels, which are the driven wheels, show characteristics such that the left and right front wheels rapidly decelerate due to the water film resistance immediately after the entry, and thereafter the deceleration becomes moderate, as shown by the solid line characteristics in FIG. . On the other hand, the control front wheel speed filter value has a lower limit than the front wheel speed sensor value by having a common upper limit when a low-pass filter is applied, as shown by the one-dot chain line characteristic in FIG.

Therefore, when the hydroplane is detected only by the degree of change of the driven wheel speed sensor value as in the prior art, it can be detected only in the section A of FIG. In the case of the example, since the detection is made based on the difference between the control front wheel speed filter value and the front wheel speed sensor value, when the vehicle enters the hydroplane state, the hydraulic pressure is accurately detected over almost the entire area B from the entry to the exit. A plane state will be detected.

Further, for example, even when the front wheel speed sensor value is suddenly decelerated instantaneously due to road surface disturbance such as when driving on a rough road,
As long as the difference from the control front wheel speed filter value from which the high frequency component has been cut does not exceed the set value V0, the hydroplane state is not detected.

Since the control front wheel speed filter value is created by setting an upper limit value for the change amounts on the acceleration side and the deceleration side, when the control front wheel speed filter value is an acceleration change amount exceeding the upper limit value, When the control front wheel speed filter value is on the acceleration side upper limit value and the control front wheel speed filter value is a deceleration change amount exceeding the upper limit value, the control front wheel speed filter value deceleration side upper limit value is effective. That is, for example, when the front wheel speed sensor value changes from deceleration to acceleration as shown in FIG. 7, the front wheel speed sensor value and the control front wheel speed filter value do not greatly separate. When the controllability of the front wheel speed filter value is used to determine the acceleration / deceleration slip state, the acceleration / deceleration slip state is properly evaluated without overestimation or underestimation. , Hydroplane condition As shown in FIG. 8, when the front wheel speed sensor value is used for control, the pseudo acceleration slip is evaluated as an excessive acceleration slip S1, whereas it is evaluated as a small acceleration slip S2. .

FIG. 9 is a flow chart showing the flow of the control operation corresponding to the hydroplane performed by the TCS / ABS-ECU. Each step will be described below.

In step 60, the high pre-flag HYP
It is determined whether F is HYPF = 1.

When it is determined YES at step 60,
The program proceeds to a step 61, wherein the engine output TE is controlled so as to maintain the vehicle speed VFTF at that time. This engine output control is performed by controlling the opening of the second throttle valve 21.

The vehicle speed VFTF is obtained by calculating the average value of the control front right wheel speed filter value VFTFR and the control front left wheel speed filter value VFTFL.

For example, TE = α × VFTF ² + β (α × VFT
The engine output TE is controlled so as to satisfy F ² ; air resistance proportional to the square of the vehicle speed, β: rolling resistance.

In step 62, it is determined whether or not the vehicle is in the acceleration slip state based on the difference between the rear wheel speed filter value and the control front wheel speed filter value.

When it is determined YES in step 62,
Proceeding to step 63, brake control is performed with the pressure increasing / decreasing speed being lower than usual.

On the other hand, if NO is determined in the step 60, the process proceeds to a step 64, in which the recover high pre-flag RH is set.
It is determined whether YF is RHYF = 0.

If it is determined YES in step 60,
Proceeding to step 65, it is determined whether or not the high pre-flag HYPF has just changed from 1 to 0. If YES, the process proceeds to step 66, where the recover high pre-flag RH
YF is set to RHYF = 1.

If RHYF = 1 is set in step 66, and if NO is determined in step 64, step 6
The program proceeds to step 7, where the filter effect is lowered to obtain a control front wheel speed filter value, and traction control using both throttle and brake is performed.

At step 68, it is determined whether or not the vehicle is in the non-acceleration slip state. If the determination is YES, the routine proceeds to step 69, where the recovery high pre-flag RHYF is set to RH.
Cleared to YF = 0.

At step 69, RHYF = 1 is set. At step 64, YES is determined. When step 65 is NO, the routine proceeds to step 70, where the control front wheel speed filter value is set by the above-described ordinary filter effect. Then, the traction control is performed by using both the throttle and the brake.

The control action corresponding to the hydroplane will be described.

When entering the hydroplane state, the flow proceeds to step 60 → step 61 → step 62 → step 63. On the throttle control side, the vehicle speed VFTF at the time of entering the hydroplane is maintained as it is regardless of the occurrence of acceleration slip. Throttle-dependent control is performed to adjust the engine output TE to
Under the condition that the acceleration slip occurs, the brake control with the low control gain is performed.

By the former throttle control, the vehicle speed VFTF at the time of entering the hydroplane state is substantially maintained, and when the vehicle is at the high vehicle speed side in the hydroplane state, vehicle deceleration due to excessive throttle throttle is suppressed, and the hydroplane state is suppressed. When the vehicle speed is low, stability degradation due to excessive opening of the throttle is suppressed.

In other words, when the normal control based on the acceleration slip is performed as it is, in the hydroplane state, the slip state of the driving wheels is overestimated due to the rapid decrease of the driven wheel speed, and the throttle control is performed regardless of the vehicle speed. On the high vehicle speed side where the engine output reduction response is low, the vehicle deceleration becomes large due to the throttle being too narrow, and on the low vehicle speed side where the engine output reduction response is high, the slip cannot be suppressed due to the excessive opening of the throttle. This leads to deterioration of stability.

According to the latter brake control, vehicle stability is ensured by suppressing the acceleration slip of the drive wheels with a good response when the accelerator is depressed in the hydroplane state.

That is, when the accelerator pedal is depressed in the hydroplane state, the drive wheels suddenly slip, as shown in FIG. 10, and brake control with good responsiveness is required. Also, at this time, when the brake control is performed by the normal control gain, the tire tends to grip due to the deceleration due to the water film resistance on the driven wheel (front wheel) side, and the driving wheel (rear wheel) side has excessive slip evaluation. As shown by the thick dotted line in FIG. 11, the rear wheels tend to lock due to the braking slip, and both the front and rear wheels lose tire grip. Therefore, as shown in FIG. 12, the brake control is performed with a lower control gain to suppress the brake pressure from becoming excessive, so that the driving wheel speed does not cause the braking slip as shown by the thin dotted line characteristic in FIG. It converges to the vehicle speed.

The operation of the hydroplane recovery control will be described.

When exiting the hydroplane state, step 60 → step 64 → step 65 → step 66
And the recover high pre-flag RHYF becomes RHYF
= 1 is set, and in the next control cycle, the process proceeds from step 64 to step 67, where traction control is performed based on the control front wheel speed filter value by the low filter effect, and the vehicle accelerates after exiting the hydroplane state. Nature is secured.

That is, when the traction control is performed based on the control front wheel speed filter value by the ordinary filter effect after the escape from the hydroplane state, the actual acceleration slip amount is S3 as shown in FIG. Nevertheless, the control driven wheel speed filter value indicated by the one-dot chain line does not readily return, and the acceleration slip amount is regarded as (S3 + S4). The excessive slip evaluation causes excessive acceleration slip control. On the other hand, as shown by the two-dot chain line characteristic in FIG. 13, the control front wheel speed filter value due to the low filter effect becomes a value close to the actual driven wheel speed, and the excessive slip evaluation is eliminated.

When the vehicle enters the non-acceleration slip state, RHYPF = 0 is cleared in step 69, and thereafter, step 60 → step 64 → step 65 → step 7
Then, the traction control is performed based on the control front wheel speed filter value based on the normal filter effect which is preferable for detecting the hydroplane state.

The effect will be described.

(1) In a hydroplane detecting apparatus for detecting a hydroplane state generated by a water film between a tire and a road surface during running, a control front wheel speed filter value VFT
The device calculates the difference between FR (VFTFL) and the front wheel speed sensor value VWFR (VWFL), and detects that the vehicle is in the hydroplane state when the difference is greater than or equal to the set value V0. The hydroplane state can be accurately detected over almost the entire area from the entry to the exit.

(2) A low-pass filter is applied to the front wheel speed sensor value VWFR (VWFL), and an upper limit value is provided for the change amount on the acceleration side and the deceleration side to control the front wheel speed filter value VWFR for control.
Because it is a device that creates FTFR (VFTFL), the front wheel speed sensor value VWFR (VWFL) and the control front wheel speed filter value VFTFR
(FFTFL), and the control front wheel speed filter value VFTFR (VFTFL) can be used to determine the acceleration / deceleration slip state.

(3) When the hydroplane state is detected, the engine output TE is controlled so as to control the throttle so that the vehicle speed VFTF is kept constant. Therefore, when the vehicle speed is high in the hydroplane state, the throttle is excessively throttled. Deceleration can be suppressed, and when the vehicle is on the low vehicle speed side in the hydroplane state, stability deterioration due to excessive opening of the throttle can be suppressed.

(4) When detecting the hydroplane, when the acceleration slip is detected by depressing the accelerator, the device is adapted to perform the brake corresponding control with a low control gain. By suppressing the acceleration slip of the wheels with good response, vehicle stability can be ensured.

(5) When the vehicle escapes from the hydroplane state, the traction control is performed based on the control front wheel speed filter value by the low filter effect until the non-acceleration slip state is reached. Acceleration can be ensured.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to this embodiment. For example, in the embodiment, the example in which the hydroplane detection device is applied to the traction control system is shown. However, the invention can be applied to other in-vehicle control systems that need to change the control content depending on whether or not the vehicle is in the hydroplane state. Of course.

[0091]

As described above, according to the first aspect of the present invention, there is provided a hydroplane detecting apparatus for detecting a hydroplane state generated by a water film between a tire and a road surface during running, and a driven wheel speed The difference between the filter value and the driven wheel speed sensor value is calculated, and when the difference is equal to or greater than a predetermined value, the device is detected as being in the hydroplane state. The effect is obtained that the hydroplane state can be accurately detected over the entire area.

Further, in the present invention described in claim 2,
A low-pass filter is applied to the driven wheel speed sensor value,
Since the means for generating a driven wheel speed filter value by setting an upper limit value for the change amount on the acceleration side and the deceleration side is provided, the followability between the driven wheel speed sensor value and the driven wheel speed filter value is good, and the driven wheel speed filter The effect is obtained that the value can be used for judging the acceleration / deceleration slip state.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims showing a hydroplane detection device of the present invention.

FIG. 2 is an overall diagram of a braking / drive system control system for a rear wheel drive vehicle to which the hydroplane detection device of the embodiment is applied.

FIG. 3 is a hydraulic circuit diagram illustrating a brake fluid pressure control system of a braking / drive system control system of the hydroplane detection device according to the embodiment.

FIG. 4 is a block diagram illustrating an outline of traction control in the embodiment.

FIG. 5 is a flowchart showing a flow of a hydroplane detection processing operation performed by an electronic control unit of the traction control system & anti-skid brake control system of the embodiment device.

FIG. 6 is a diagram showing a front wheel speed sensor value characteristic and a control front wheel speed filter value characteristic in the embodiment device.

FIG. 7 is a diagram showing a drive wheel speed characteristic, a front wheel speed sensor value characteristic, and a control front wheel speed filter value characteristic when shifting from deceleration to acceleration in the embodiment apparatus.

FIG. 8 is a graph showing wheel speed characteristics in a hydroplane state.

FIG. 9 is a flowchart showing a flow of a hydroplane-compatible control processing operation performed by the electronic control unit of the traction control system & anti-skid brake control system of the embodiment device.

FIG. 10 is a characteristic diagram of a vehicle speed, a drive wheel speed, and a driven wheel speed when an accelerator is depressed after entering the hydroplane.

FIG. 11 is a comparison characteristic diagram of drive wheel slip convergence with a normal control gain and a low control gain when brake control is performed after entering the hydroplane.

FIG. 12 is a brake pressure characteristic diagram in brake control with a normal control gain and a low control gain.

FIG. 13 is a graph showing wheel speed characteristics when an accelerator pedal is depressed after exiting the hydroplane state.

[Explanation of symbols]

 a driven wheel speed sensor b, b 'driven wheel speed filter value creating means c hydroplane detecting means

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B60T 8/58-8/86 B60K 41/20 F02D 29/02 G01P 3/56

Claims (2)

(57) [Claims] A driven wheel speed sensor for detecting a driven wheel speed; and a driven wheel speed filter value generating means for generating a driven wheel speed filter value by applying a low pass filter having a predetermined cutoff frequency to the driven wheel speed sensor value. And a hydroplane detecting means for calculating a difference between the driven wheel speed filter value and the driven wheel speed sensor value, and detecting that the hydroplane state is established when the difference is equal to or greater than a predetermined value. Features Hydroplane detector. 2. A driven wheel speed sensor for detecting a driven wheel speed, a low-pass filter having a predetermined cut-off frequency applied to the driven wheel speed sensor value, and an upper limit value provided for an amount of change on the acceleration side and a deceleration side. Driven wheel speed filter value generating means for generating a driven wheel speed filter value, calculating a difference between the driven wheel speed filter value and the driven wheel speed sensor value, and in a hydroplane state when the difference is equal to or more than a predetermined value. A hydroplane detecting device, comprising: a hydroplane detecting means for detecting that there is a hydroplane.