JPH10331676A - Slip preventive device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate use of a wheel speed sensor, and conduct slip prevention control even for an all-wheel-drive vehicle by computing a difference in rotational speed from engine rotational speeds at present and previous time, and discriminating the generation and convergence of slip based on the difference in the rotational speed. SOLUTION: While an engine 4 is being operated, a control means 16 subtracts engine rotational speed at previous time value from an engine rotational speed detected by an engine rotational speed sensor 18 to obtain a difference in engine rotational speed. A slip discrimination value is set by retrieving it from a slip discrimination value map, the slip discrimination value is compared with the difference in engine rotational speed. When the difference in engine rotational speed is smaller than the slip discrimination value, it is discriminated as no generation of slip. When it is larger, on the contrary, it is discriminated as generation of slip, a slipping vehicle speed increasing amount estimation value is cleared if slip occurs, and the engine rotational speed at previous time is set as reference vehicle speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-slip device for a vehicle, and more particularly to an anti-slip device for a vehicle capable of appropriately performing anti-slip control of driving wheels with a simple structure.

[0002]

2. Description of the Related Art In a vehicle, when slippage occurs in a driving wheel, control is performed so as to prevent slippage of the driving wheel.
Some are provided with an anti-slip device.

In general, this slip prevention device is provided with a wheel speed sensor for detecting a rotational speed on each of a driving wheel and a driven wheel, and determines occurrence of a slip and convergence of the slip on the basis of a difference in rotational speed between the driving wheel and the driven wheel. And anti-slip control.

[0004] Such a slip prevention device is disclosed in, for example, JP-A-3-229968 and JP-A-4-59.
No. 454 and Japanese Patent Application Laid-Open No. 7-127491. Japanese Unexamined Patent Publication No. Hei 3-229968 discloses that a slip ratio between tire road surfaces is calculated based on a rotation speed of a driving wheel and a rotation speed of a driven wheel. The traction control is performed by reducing the amount of fuel supplied to the engine by the valve to reduce the driving force and changing the target engine output characteristic with respect to the accelerator operation amount. Japanese Unexamined Patent Application Publication No. 4-59454 discloses a technique that suppresses the execution of the slip prevention control when the catalyst temperature is higher than a predetermined temperature, thereby suppressing the emission of unburned gas. Japanese Unexamined Patent Publication No. Hei 7-127491 estimates the occurrence of a slip of a drive wheel in a running state of a vehicle, suppresses the occurrence of a slip of a drive wheel, and stabilizes the running state.

[0005]

Conventionally, in a slip prevention device, it is necessary to detect a vehicle speed by a wheel speed sensor of a driven wheel in order to determine occurrence of slip of a drive wheel and convergence of the slip. was there.

For this reason, the number of parts increases and the structure becomes complicated. In addition, all-wheel drive vehicles do not have driven wheels that are always equivalent to the vehicle speed. In such a case, there is a disadvantage that the slip prevention control cannot be appropriately performed.

[0007]

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned disadvantages, the present invention provides a vehicle anti-slip device for preventing and controlling the slip of a drive wheel when the drive wheel is in a slip state. A control means is provided which is provided with a determination unit which calculates an engine speed difference value from the previous engine speed value and determines slip occurrence and slip convergence based on the engine speed difference value. I do.

[0008]

According to the present invention, the occurrence of slip and the convergence of slip are determined by the amount of change in the engine speed, so that a wheel speed sensor is not required, the number of parts is reduced, and the configuration is simplified. Slip prevention control can be appropriately performed even in an all-wheel drive vehicle.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; 1 to 9 show a first embodiment of the present invention. In FIG. 7, 2 is a vehicle, 4 is an engine, 6 is a transmission, 8 is front wheels, and 10 is rear wheels.

As shown in FIG. 8, the engine 4 includes:
The ignition timing control mechanism 12 and the fuel injection control mechanism 14 are in communication.

The ignition timing control mechanism 12 and the fuel injection control mechanism 14 are provided in a control means 16. An engine speed sensor 18 for detecting the engine speed, a gear position sensor 20 for detecting the gear position of the transmission 6, and other sensors are connected to the control means 16.

The control means 16 receives various signals from various sensors and operates the ignition timing control mechanism 12 and the fuel injection control mechanism 14 to control the operating state of the engine 4. Further, the control means 16 calculates an engine speed difference value from the engine speed and the previous value of the engine speed, and determines the occurrence of slip and the convergence of the slip based on the engine speed difference value. Have.

The control means 16 sets a reference vehicle speed when it is determined that a slip has occurred, and determines the convergence of the slip based on the speed increase from the reference vehicle speed and the estimated vehicle speed increase during slip from the reference vehicle speed. Is determined, and the slip ratio is calculated and defined while the slip is continuing, and the torque reduction amount is determined based on the slip ratio, and the slip amount is fed back to the torque reduction amount.

Next, the operation of the first embodiment will be described with reference to FIGS.
A description will be given based on the flowchart of FIG.

In the slip occurrence determination routine of FIG. 1, when the program of the control means 16 is started, it is determined whether the slip flag is "1" during slip occurrence or "0" without slip (step 102).

In step 102, when there is no slip and the slip flag is "0", the engine speed (NE) is used to calculate the engine speed last value (NE previous value).
Is calculated (step 104) (see FIG. 3).

A slip determination value (DNEL) is retrieved from the slip determination value (DNEL) map shown in FIG. 4 and set (step 106).

Then, the engine speed difference value (DNE)
Is compared with the slip determination value (DNEL) to determine whether or not a slip has occurred (step 108).

[0019] Whether there is the generation of the slip, for example, in FIG. 3, for example, the engine rotational speed difference value at t ₄ time (DNE4) is slip determination value at this time (D
Since NEL) less than, it is determined that slip is not occurring, the engine rotational speed difference value at the next t ₅ time (DNE5), slip determination value at this time (DNE
L), it is determined that a slip has occurred.

In step 108, DNE> DNE
In the case of L, a slip occurs, and in the case of YES, the estimated value of the vehicle speed increase at slip (VS) is cleared, that is, V
S = 0 (step 110), and the reference vehicle speed (VSB) is set, that is, VSB = NE the previous value (step 112). Then, the slip flag is set, that is, flag = 1 (step 114). ).

On the other hand, in step 108, DN
If E <DNEL, no slip, and NO, the program is returned (step 116).

In step 102, when the slip is occurring and the slip flag is "1", and after the flag is set to 1 in step 114, the routine proceeds to the slip convergence determination routine shown in FIG. Determine convergence.

In the slip convergence determination routine shown in FIG. 2, the vehicle speed increase per sampling (DV)
Is retrieved from the DV table of FIG. 5 and set (step 202). The vehicle speed increase (DV) per sampling is determined by the gear position.

Further, an estimated value of the vehicle speed increase during slip (VS) is calculated by VS = VS previous value + DV (step 204).

Further, the speed increase (JV) from the reference vehicle speed (VSB) is calculated by JV = NE-VSB (step 206).

The slip convergence is determined by comparing the speed increase (JV) from the reference vehicle speed (VSB) with the estimated vehicle speed increase during slip (VS) (step 208).

In step 208, if JV ≧ VS,
In the case of YES while the slip is continuing, the slip ratio (S
R) is calculated and defined as SR = JV ÷ VS (step 210).

[0028] In the calculating the slip rate (SR), for example, in FIG. 9, at t ₅ when it is determined the generation of the slip, the engine speed previous value (NE4) and a reference vehicle speed (VSB) , This reference vehicle speed (VSB)
Is calculated, that is, JV ₅ = NE ₅ −VSB at time t ₅ . Then, a vehicle speed increase per sampling (DV) is retrieved from the DV table of FIG. 5 and set, and a vehicle speed increase estimated value (VS) from a reference vehicle speed (VSB) at the time of slip is calculated. in other words, t ₅ time, VS ₅ = DV, and (t _{6 time, VS 6 = VS 5 + DV} ). This JV _5, VS
₅ calculates a slip rate (SR) from, i.e., t ₅ times, and SR ₅ = JV ₅ ÷ VS _5, and, when the next sampling (t _6), the speed of the reference vehicle speed of above (VSB) The calculation is performed again from the calculation of the increase amount (JV). That is,
Slip ratio (SRn) = JVn ÷ VSn is calculated (n = 5, 6, 7, 8).

That is, the speed increase (J) from the reference vehicle speed (VSB) obtained in the process of calculating the slip ratio (SR).
V) and the reference vehicle speed (VSB), when the estimated value of the vehicle speed increase (VS) satisfies VS ≧ JV, it is determined that the slip has converged. In t ₉ Sample time points in FIG. _{9, NE 9 -VSB = JV 9} , VS 8 + DV = VS 9 is calculated, since the VS ₉ ≧ JV _9, at which time (t _9), determines that the skid convergence To end the torque reduction control.

Then, during the continuation of the slip, the torque reduction amount (for example, the ignition retard amount) is searched from the ignition retard amount map of FIG. 6, that is, the slip ratio (SR) and the gear position are determined. , The ignition retard amount is searched, and the ignition timing control mechanism 12 reduces the torque by the ignition retard amount (step 21).
2).

After the processing of step 212, the program is returned (step 214).

On the other hand, in step 208, the JV
If ≤VS and the slip converges and is NO, the slip flag is cleared, that is, the flag is set to 0 (step 216), and the program returns (step 21).
8).

As a result, the occurrence of a slip and the convergence of the slip are determined based on the amount of change in the engine speed.
Eliminates the need for conventional wheel speed sensors, reduces the number of parts,
The structure can be simplified and the cost can be reduced. Slip prevention control can be appropriately performed even in a vehicle having no driven wheels (all-wheel drive vehicle). In addition, slip prevention can be performed even in a vehicle having a wheel speed sensor. In control, it can be used as a backup at the time of sensor failure.

In the method of defining the slip ratio (SR) and determining the ignition retard amount based on the slip ratio (SR), the slip amount (SD) is fed back to the torque reduction amount, so that the slip prevention control is improved. Can be performed.

FIGS. 10 to 17 show a second embodiment of the present invention.

In the second embodiment, the control means 16
Performs the determination of the occurrence of slip in the same manner as in the first embodiment, but determines the slip convergence differently from the case of the first embodiment.

Next, the operation of the second embodiment will be described with reference to FIG.
Description will be made based on the flowchart of FIG.

In the slip occurrence determination routine of FIG. 10, when the program of the control means 16 is started, it is determined whether the slip flag is "1" during slip occurrence or "0" without slip (step 302).

In step 302, when there is no slip and the slip flag is "0", the engine speed (NE) is used to calculate the engine speed last value (NE previous value).
Then, the engine speed difference value (DNE) is calculated (step 304) (see FIG. 12).

The slip determination value (DNEL) is retrieved from the slip determination value (DNEL) map of FIG. 13 and set (step 306).

Then, the engine speed difference value (DNE)
Is compared with the slip determination value (DNEL) to determine whether or not a slip has occurred (step 308).

Whether or not the slip has occurred can be determined by, for example, referring to the engine speed difference value (DNE4) at time t _{4 in} FIG. 12 based on the slip determination value (DNE) at this time.
Since L) smaller than, it is determined that slip is not occurring, the engine rotational speed difference value at the next t ₅ time (DN
In E5), since it is larger than the slip determination value (DNEL) at this time, it is determined that a slip has occurred.

In step 308, DNE> DNE
In the case of L, a slip occurs, and in the case of YES, the estimated value of the vehicle speed increase at slip (VS) is cleared, that is, V
S = 0 (step 310), and the reference vehicle speed (VSB) is set, that is, VSB = NE the previous value (step 312). Then, the slip flag is set, that is, flag = 1 (step 314). ).

On the other hand, in step 308, DN
If E <DNEL, no slip, and NO, the program is returned (step 316).

In the case where the slip flag is "1" during the occurrence of a slip in the step 302 and after the flag is set to 1 in the step 314, FIG.
The routine shifts to the slip convergence determination routine to determine the convergence of the slip.

In the slip convergence determination routine of FIG. 11, the speed increase (JV) from the reference vehicle speed (VSB) is calculated by JV = NE-VSB (step 402).

Then, the speed increase (JV) from the reference vehicle speed (VSB) is compared with the slip-time estimated vehicle speed increase value (previous VS value) to determine whether the slip has converged (step 404).

In step 404, JV> VS
If the previous value is YES while the slip is continuing, the slip amount (SD) is calculated by SD = JV-VS previous value (step 406).

Then, the power transmission ratio during slip (DR)
Is retrieved from the DR map of FIG. 15 and set (step 408).

Then, the vehicle speed increase per sampling (DVS) is calculated by DVS = SD × DR (step 410).

Next, the estimated vehicle speed increase during slip (VS) is calculated by VS = VS previous value + DVS (step 412).

Next, the slip ratio (SR) is calculated as SR = J
It is calculated by V ÷ VS (step 414).

Then, based on the slip ratio (SR) and the gear position, the ignition retard amount is determined from the ignition retard amount map of FIG. 16 (step 416), the torque is reduced by the ignition timing control mechanism 12, and the program is returned. (Step 418).

On the other hand, in step 404, the JV
<If the previous value of VS is NO for slip convergence, the slip flag is cleared, that is, the flag is set to 0 (step 420), and the program is returned (step 4).
12).

That is, in the slip convergence determination routine of FIG. 11, if it is determined that the slip is continuing,
The vehicle speed at the time of slip is estimated by 4. This figure 1
In 4, for example, NE previous value of the time it is determined that slip occurs t ₅ when the (NE4), the reference vehicle speed (VS
B). Then, the speed increases from the reference vehicle speed (VSB) and (JV), t ₅ time, JV ₅ = NE ₅ -V
Calculate with SB. Next, the slip amount (SD) is calculated,
In other words, the difference in speed increase and (JV) vehicle speed increment estimated value (VS) the previous _{value, SD 5 = JV 5 -0 (} t 5 _{times, VS 4 = 0), (} SD 6 = JV 6 - VS ₅ (at time t ₆ )). Next, the power transmission rate during slip (D
R) is searched and set from the DR map of FIG. 15, and
The vehicle speed increase per sampling (DVS) is given by D
Calculated as VS ₅ = SD ₅ × DR ₅ (at time t ₅ ). Next, the estimated value of the vehicle speed increase during slip (VS) is expressed by VS
₅ = 0 + DVS ₅ (at time t ₅ , VS ₄ = 0), (VS ₆
= VS ₅ + DVS ₆ (at time t ₆ )), and the next sampling (t ₆ ) is performed again by calculating the above speed increase (JV).

In the calculation of the slip ratio (SR) and the torque reduction control, as shown in FIG. 17, when it is determined that the slip is continuing, the latest estimated value of the vehicle speed increase during slip (VS) is determined. Is calculated (step 412), and VS
n and JVn, the slip ratio (SRn) is calculated as SRn =
JVn ÷ VSn is calculated (step 414), the ignition retard amount is determined from the ignition retard amount map of FIG. 16 based on the slip ratio (SRn) and the gear position, and the torque is reduced.

On the other hand, in determining the slip convergence, after calculating the speed increase (JV), the JVn (the latest value) is calculated.
And VSn _-1 by comparing the (previous value) when it becomes a VSn _-1 ≧ JVN, it determines that the slip has converged, the time sampling t ₁₀ in FIG. 17, since the JV ₁₀ ≦ VS _9,
It is determined that the slip has converged, and the torque reduction control ends.

Thus, the same effect as in the first embodiment can be obtained, and since the vehicle speed at the time of slip is estimated as shown in FIG. 14, the occurrence of slip and the convergence of slip can be determined more finely. Therefore, the torque reduction control can be appropriately performed.

In the first and second embodiments, the ignition retard amount is used as the torque reduction control of the engine 4. However, it is also possible to use other means such as ignition thinning and fuel injection cut. It is.

[0060]

As apparent from the above detailed description, according to the present invention, the engine speed difference value is calculated from the engine speed and the previous value of the engine speed, and the slip is calculated based on the engine speed difference value. By providing a control means provided with a determination unit for determining occurrence of slip and convergence of slip, the occurrence of slip and convergence of slip are determined based on the amount of change in the engine speed. The number of points is reduced to simplify the configuration, and the anti-slip control can be appropriately performed even in an all-wheel drive vehicle.

[Brief description of the drawings]

FIG. 1 is a flowchart of a slip occurrence determination routine in a first embodiment.

FIG. 2 is a flowchart of a slip convergence determination routine in the first embodiment.

FIG. 3 is a time chart of slip occurrence determination.

FIG. 4 is a diagram of a slip determination value map.

FIG. 5 is a diagram of a DV table.

FIG. 6 is a diagram of an ignition retard amount map.

FIG. 7 is a schematic view of a vehicle.

FIG. 8 is a block diagram of a slip prevention device.

FIG. 9 is a time chart in the first embodiment.

FIG. 10 is a flowchart of a slip occurrence determination routine in the second embodiment.

FIG. 11 is a flowchart of a slip convergence determination routine in a second embodiment.

FIG. 12 is a time chart of slip occurrence determination.

FIG. 13 is a diagram of a slip determination value map.

FIG. 14 is a time chart for estimating the vehicle speed during slip.

FIG. 15 is a diagram of a DV table.

FIG. 16 is a diagram of an ignition retard amount map.

FIG. 17 is a time chart in the second embodiment.

[Explanation of symbols]

 2 Vehicle 4 Engine 12 Ignition timing control mechanism 16 Control means 18 Engine speed sensor 20 Gear position sensor 22 Judgment unit

Claims (3)

[Claims] An anti-slip device for a vehicle that controls slippage of a drive wheel when the drive wheel is in a slip state, calculates an engine speed difference value from an engine speed and a previous value of the engine speed, and calculates the engine speed. A slip prevention device for a vehicle, comprising: a control unit provided with a determination unit that determines occurrence of a slip and convergence of the slip based on the number difference value. 2. The control means sets a reference vehicle speed at the time of determining the occurrence of the slip, and calculates a reference value based on a speed increase from the reference vehicle speed and a slip vehicle speed increase from the reference vehicle speed. The slip prevention device for a vehicle according to claim 1, wherein the convergence of the slip is determined, and the slip ratio is calculated while the slip is continuing. 3. The slip prevention device for a vehicle according to claim 2, wherein the control unit determines a torque reduction amount based on the slip ratio.