JPH03258933A - Control device for driving wheel torque - Google Patents

Abstract

PURPOSE:To improve trancient responsibility by determining the initial throttle opening by effective torque determined from driving wheel total torque and surplus torque when feedback control of the throttle opening is started in order to restrict excessive slip of driving wheels. CONSTITUTION:When feedback control of the opening of a throttle valve 9 is started to restrict excessive slip of driving wheels Wr, a driving wheel torque reducing means U determines driving wheel effective torque by means of a calculating means 103 from driving wheel total torque calculated by a calculating means 101, and surplus torque consumed by excessive slip, calculated by a calculating means 102. The initial throttle opening is determined by a calculating means 104 based on the driving wheel effective torque. When the excessive slip is large, fuel cut is performed by a fuel cutting means 10, and when the excessive slip is reduced to shift to feed-back control, this initialization is effective. Thus, driving wheel torque can be quickly converged to an optimum value.

Description

DETAILED DESCRIPTION OF THE INVENTION A3 Object of the Invention (1) Field of Industrial Application The present invention relates to a drive wheel torque control device used for traction control to prevent excessive slip of the drive wheels.

(2) Conventional technology In the so-called traction control system that prevents excessive slip of the driving wheels when starting or accelerating a vehicle, it is known that the system performs feedback control on the throttle opening of the internal combustion engine as a means of reducing driving wheel torque. (See, for example, Japanese Patent Laid-Open No. 62-7954). According to such a drive wheel torque control device, the drive wheel torque is controlled so that the drive wheel slip is at an optimal value, and it is possible to obtain the optimal driving force that matches the coefficient of friction of the road surface and the driving condition of the vehicle. .

(3) Problems to be Solved by the Invention However, in conventional drive wheel torque control devices, the previous throttle opening or a constant value is used as the initial throttle opening at the start of throttle opening feedback control. However, there was a time delay before the throttle opening reached the target drive wheel slip, which caused problems with transient response. In particular, when the drive wheel slip is large, the fuel is cut to suppress the drive wheel torque.
In a system that shifts to feedback control of the throttle opening after the slip ratio decreases, there is a problem in that it is difficult to smoothly change the driving wheel torque when shifting from fuel cut to throttle opening control.

The present invention has been made in view of the above-mentioned circumstances, and when performing feedback control of the throttle opening to provide optimal driving wheel slip, it provides more precise throttle opening by giving an appropriate initial throttle opening at the start of the feedback control. The purpose is to control drive wheel torque.

B1 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides, as shown in FIG. A driving wheel torque control device comprising a driving wheel torque reducing means for suppressing the excessive slip by feedback controlling the opening degree of a throttle valve of an internal combustion engine connected to the driving wheels, wherein the driving wheel torque reducing means includes the driving wheel torque reducing means for suppressing the excessive slip. means for determining the total torque of the drive wheels; means for determining the surplus torque consumed by excessive slip of the drive wheels; means for determining the effective torque of the drive wheels from the total torque and the surplus torque; and means for determining the effective torque of the drive wheels from the effective torque. and means for determining the initial throttle opening when controlling the valve to close.

At this time, the surplus torque can be determined from the slip change rate of the drive wheels, and the effective torque can be determined by linear approximation from the total torque and the drive wheel slip change rate.

In addition, if this driving wheel torque control device has a means for cutting fuel when excessive slip of the driving wheels is large, it is desirable that the initial throttle opening is determined when the fuel is restored from the fuel cut state, and in that case, The effective torque can be determined from the maximum edge torque and the maximum surplus torque of the driving wheels within a predetermined time from the start of the fuel cut.

Furthermore, the means for determining the total torque of the drive wheels includes means for calculating crankshaft torque from engine operating conditions, filtering means for filtering the calculated crankshaft torque, and gear ratio and transmission transmission for the filtered crankshaft torque. It can be composed of means for multiplying efficiency.

0] Effect According to the above configuration, first, the total torque of the driving wheels and the surplus torque consumed for slipping of the driving wheels are determined, and from the difference between these total torque and the surplus torque, the amount of the driving wheels consumed to accelerate the vehicle is determined. The effective torque of Subsequently, the throttle opening degree for drawing out the effective torque is determined as the initial throttle opening degree, and based on this initial throttle opening degree, feedback control of the throttle opening degree of the internal combustion engine is started in order to prevent excessive slip of the drive wheels. Ru.

This control device has a means for cutting the fuel when the excessive slip of the driving wheels is large, and is particularly effective when applied when the excessive slip decreases and the control shifts from fuel cut to throttle opening feedback control. In addition, by applying filtering processing when estimating the crankshaft torque, it is possible to absorb the time delay error from when the engine operating condition changes until the crankshaft torque actually changes, and to reduce the drive wheel torque even during the transition period. can be accurately grasped.

(3) Examples Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 2 is a schematic configuration diagram of a vehicle equipped with this control device, and this vehicle is equipped with a pair of drive wheels Wr and a pair of driven wheels Wf driven by an internal combustion engine E.
r and the driven wheel Wf are respectively provided with a driving wheel speed detector l and a driven wheel speed detector 2 that detect their speeds V- and Vv. The internal combustion engine E is provided with a rotational speed detector 3 consisting of a gear and an electromagnetic pickup for detecting the rotational speed Ne of its crankshaft, and a gear position detector 5 for detecting the gear position of its transmission 4. In addition, the intake passage 6 is provided with an intake pipe internal pressure detector 7 for detecting the intake pipe internal pressure PR, and a throttle valve 9 connected to a pulse motor 8 and driven to open and close. A fuel injection valve 11 having a fuel cut means 10 is provided. Further, as other detectors, an atmospheric pressure detector 12 that detects the atmospheric pressure PA, and a water temperature detector 18 that detects the temperature TW of the cooling water in the water jacket are provided. The driving wheel speed detector 1, the driven wheel speed detector 2, the rotational speed detector 3, the gear position detector 5, the intake pipe internal pressure detector 7, the pulse motor 8, the fuel cut means 10. atmospheric pressure detector 12,
The water temperature detector 18 is connected to an electronic control unit U consisting of a microcomputer.

FIG. 3 shows an electronic control unit (U) for processing the detection signals inputted from the respective detectors based on a control program and driving the throttle valve 9 via the pulse motor 8. This electronic control unit U includes a central processing unit (CPU) 13 for performing the arithmetic processing and processing, and a read-only memory that stores data such as the control program and various maps. 7 (ROM) 14, Random access memo that temporarily stores the detection signals and calculation results of each of the above-mentioned detectors! J (RAM>15, each of the above-mentioned detectors, namely driving wheel speed detector 1, driven wheel speed detector 2, rotational speed detector 3, gear position detector 5, intake pipe internal pressure detector 7,
It is composed of a fuel cut means 10, an atmospheric pressure detector 12, a human power section 6 to which a water temperature detector 18 is connected, and an output section 17 to which the pulse motor 8 is connected. The electronic control unit U uses the central processing unit 13 to perform arithmetic processing on each detection signal input from the human power section 16 and the data stored in the read-only memory 4, based on a control program to be described later. , and finally drives the pulse motor 8 via the output 817. As a result, the throttle valve 9 is controlled to close, and the output torque of the internal combustion engine E changes.
As a result, the drive wheel torque is controlled to an optimal value in order to suppress excessive slip of the drive wheels Wr of the vehicle.

Next, the details of the drive wheel torque control executed in the electronic control unit (U) will be explained in detail based on the flowcharts of FIGS. 4 to 6. Note that the flowchart in Figure 5 is
This shows a subroutine corresponding to step S3 in the figure, and the flowchart in FIG. 6 corresponds to step S2 in FIG.
5 shows a subroutine corresponding to No. 5.

In FIG. 4, in step Sl, the fuel cut means l
Based on the signal from E, it is determined whether or not the fuel is being cut, and in step S2, the rotational speed Ne of the internal combustion engine E is determined to be 150% based on the detection signal of the rotational speed detector 3.
It is determined whether or not it is less than or equal to ORPM. Then, the process proceeds to step S3 only if the fuel is being cut and Ne>150 ORPM, and in other cases, the process proceeds to step S4. In addition, fuel cut is driven wheel slip V
', that is, from the driving wheel speed Vw output by the driving wheel speed detector 1 to the driven wheel speed Vv output by the driven wheel speed detector 2
This is performed when it is determined that the difference between the reference speed (I) and Y, which is a function of , is sufficiently large, and it is determined that the drive wheel Wr is slipping excessively. Here, the above V and Vip are VE=V, -vup Vtp=F (Vv)=*VV However, K is expressed as a constant.

Now, if the fuel is being cut and the condition Ne>150ORPM is not satisfied, a throttle feedback cycle which is a function of the rotational speed Ne of the internal combustion engine E is searched based on the map in step S4. In the following step s5, it is determined whether or not it is a feedback cycle, and if YES, the control coefficient K THP I KTIII + KTIII is determined in order to perform PID feedback control of the throttle opening in step S6.
+” is determined.

Next, in step S7, it is determined whether or not throttle feedback was performed last time. If YES, in step S8, the item ■; θ, □F111N is
″ = θT)!Fll! '-' KT
III ”*Vi is calculated based on ``*Vi.The negative sign of the second term on the right side in the above equation is because VE larger than zero is taken as a positive direction.On the other hand, step S
7 is N○, the initial throttle opening θTlllNl7, which will be detailed later, is set to θA IIFB in step S9.
Replaced by I0. Once the first term; θa EPBI is determined, restrictions are added to the first term in steps SIO to S13 below. That is, step S10
θa8□1 is the throttle opening θa that compensates for the friction of the internal combustion engine E. It is determined whether it is 1 or more, and NO
If so, θa at step Sll. 9 is replaced with θT□□. Further, in step SL2, θa8□1 is the throttle opening θ which is 80% of the throttle opening at which the internal combustion engine generates the maximum torque. It is determined whether or not it is less than or equal to T', and N
If O, θway・ is θTIIF1r in step S13.
replaced by Next, in step 314, the second term;
It is calculated based on Vil, and further set to 0 in step S15.
The term θ7□FilDN is calculated based on θTIIFI11'=KTHD*Vi.

Subsequently, in step S16, the feedback control amount θa8
□ is θT, I□=θTHPmr-θtapHp-θT8□.

When calculated based on In steps SL7 to S20, a limit is added to the feedback control amount θARPB. That is, in step S17, θa□1. is the aforementioned θa. It is determined whether or not 9 or more, and if NO, in step 318 θTo” is determined to be θ
Replaced by T□. Also, in step S19, θTH
FB is the aforementioned θ. It is determined whether or not it is 7' or less,
If NO, θ in step S20. ,. is θaIIFI
Replaced by I.

Now, during the fuel cut in step S1 and step S2, if the conditions of .degree. and Ne>150ORPM are satisfied, step s3, that is, the subroutine shown in the flowchart of FIG. 5 is executed with an interruption of 10m5. First, in step S21, it is determined whether the previous fuel cut flag FF/C is zero or not.
In the case of O, that is, when the fuel is being cut, the throttle initialization flag F is further set in step S22.
It is determined whether THINIT is zero or not. If YES, the process moves to step S25, and if NO, it is assumed that the initial throttle opening degree θTHTMIT has already been determined, and the process moves to step S32, which will be described later. Further, if the fuel cut flag FF/C is zero in step S21, that is, if fuel cut is performed for the first time, the throttle initialization counter is set to 100 m5 and started in step 323. Then, in the following step S24, the throttle initialization flag FTHI□ is set.

is reset to zero and the process moves to step S25.

Now, in step S25, the crankshaft torque TQou
T is determined as a function of the intake pipe internal pressure Pi and the rotational speed Ne of the internal combustion engine. That is, in step 338 in FIG. 6, which is a subroutine of step S25,
The maximum crankshaft torque TQ114X when the throttle is fully open is searched from the table in accordance with the current rotational speed Ne of the internal combustion engine E. Next, in step S39, the intake pipe internal pressure P when the throttle is fully open is adjusted in accordance with the rotational speed Ne of the internal combustion engine E. A and intake pipe internal pressure P under no load. L is retrieved from the table. Next, in step S40, the water temperature correction coefficient Ktwa is searched from the table based on the output signal of the water temperature detector 18, and in step S41,
Based on the output signal of the atmospheric pressure detector 12, the atmospheric pressure correction coefficient K FATll is searched from the table. Then, in step S42, the intake pipe internal pressure P□OT when the throttle is fully open, the intake pipe internal pressure PIIIL when no load is searched in step S39, and the current intake pipe internal pressure P8.
The intake pipe internal pressure correction coefficient Kp is determined by the following linear correction formula.
ntu is calculated.

Kpat-= (P m P vl, IL) /
(P 1w0T P INL ) Next, step S4
At 3, the air-fuel ratio flag Fw. 1 is set, and if the air-fuel ratio flag Fwot is set,
That is, in a normal operating state, 1 is selected as the air-fuel ratio correction coefficient K_AFTll in step S44.

Also, the air-fuel ratio flag F. , is not set, that is, when the load is low, etc., the air-fuel ratio correction coefficient KAFT is set as the predetermined value KA, T, in step S45. (0
, 9) are selected. Then, in step 346, the crankshaft maximum torque TQM retrieved in step 338 is determined.
AX is the intake pipe internal pressure correction coefficient K calculated in step S42.
PI17. By multiplying the current intake pipe internal pressure P,
The crankshaft torque corresponding to is calculated, and the result is the water temperature correction coefficient K TWTI retrieved in step S40.
, atmospheric pressure correction coefficient K pAr searched in step S41
, s and the air-fuel ratio correction coefficient KAF7 selected in step S44 or step S45 are multiplied to estimate the current crankshaft torque TQoUT. In addition, the intake pipe internal pressure P when the throttle is fully open! Instead of estimating the crankshaft torque TQ, , a using IWOτ and the intake pipe internal pressure PB at no-load, a, the maximum crankshaft torque TQ, It is also possible to estimate one IA.

Now, as described above, the crankshaft torque TQouT is estimated in step S25 in FIG.
There is some time delay before the actual change in A actually occurs because it takes time for the air detected by the intake pipe internal pressure detector 7 to be sucked into the internal combustion engine E, compressed and exploded. For this purpose, in the subsequent step S26, the crankshaft torque TQOUT is subjected to first-order lag filtering processing based on the following equation.

T Qout ” = α * T QOUT ’ + (
1-α)*TOOLIT (0 × α × 1>) This filtering process absorbs the error due to the above-mentioned time delay, and even during the transition period of the operating state of the internal combustion engine E, the rank shaft torque TQa becomes precise at each moment. , is estimated.

Next, in step S27, the filtered crankshaft torque TQout is multiplied by the transmission transmission coefficient determined according to the output signal of the gear position detector 5 by the gear ratio G/R. , drive wheel edge torque TQo from the following equation.

TI is calculated.

TOOLI? ”=K)l*G/R*TQO
In LI7 step 328, the drive wheel slip change rate
The maximum value Vl:M over the past 100 m5 and the maximum value TQoutx'' over the past 100 m5 of the driving wheel edge torque TQou,r'' are searched. That is, the driving wheel slip is the differential value of the driving wheel slip V6 calculated based on the driving wheel speed Vw output from the driving wheel speed detector 1 and the driven wheel speed V output from the driven wheel speed detector 2. Rate of change VH1 and the driving wheel edge torque TQout
” is temporarily stored in the random access memory 15,
Among them, the maximum value V0S and maximum value TQ in the past 100m5. 1Jrll'' is selected.Next, in step S29, it is determined whether 100m5 has elapsed, and N
In the case of O, the above-mentioned θa is determined in step S30. ' is replaced with the initial throttle opening degree θa11rllT. On the other hand, if YES in step S29, step S
Effective torque TQ, which is used to accelerate the vehicle at 31.

TT<that is, the drive wheel edge torque TQOUT'' minus the surplus torque consumed by the excessive slip of the drive wheel Wr) is the maximum value O- of the drive wheel slip change rate obtained in step 328 above and the drive wheel Maximum value of edge torque TQ
The map is searched from ``outT,''.

Next, in step S32, the initial throttle opening θTllTl
1, T is calculated by the following equation.

Here, aTH/aTQ indicates the throttle opening change required to give a unit torque change at the crankshaft, and is stored as a function of the rotational speed Ne of the internal combustion engine E. In addition, KPA is the above dTH/
This is a correction coefficient determined based on the output signal of the atmospheric pressure detector 12 in order to correct ciTQ.

In this way, the initial throttle opening θTIIIIII7
Once obtained, the next steps 333 to S36 are performed.
Similarly to the above, the minimum value is limited to 0° and 0, and the maximum value is limited to 01° and 1. Finally, in step S37, the throttle initialization flag F_TIIIT is set to 1.

Thus, when throttle feedback control is newly started in step S9 of FIG. 4, the aforementioned θT)IINI7 is used as the initial throttle opening.

The above-mentioned initial throttle opening degree θTlllN1 is the driving wheel effective torque TQ+wrt used for acceleration of the vehicle,
In other words, the driving wheel Wr is calculated from the driving wheel edge torque TOOLIT.
This corresponds to the throttle opening that provides the torque after subtracting the excess torque consumed by excessive slip, making it possible to quickly converge the final throttle opening to a value that provides the optimal drive wheel slip ratio. .

Next, another embodiment for obtaining the driving wheel effective torque TQrNIT will be described.

Figure 7 shows how the relationship between the driving wheel edge torque TQo++,'' and the driving wheel slip rate of change 06 changes for various road surface friction coefficients μ, using linear approximation. It is understood that the ratio of ineffective torque increases as the driving wheel slip change rate 08 increases.Thereby, the road surface μ is determined from the intersection of the driving wheel edge torque T 0OLI7 ” and the driving wheel slip change rate O9, and the road surface μ
Drive wheel effective torque TQIN from the position where the line intersects with the horizontal axis
rT can be obtained. Therefore, various road surfaces μ
By storing the driving wheel edge torque TQouT'' and the driving wheel slip change rate </ε as functions in the read-only memory 14, the effective driving wheel torque TQxxrt can be stored in the read-only memory 14 as functions.
can be found.

C1 Effects of the invention As described above, according to the present invention, when starting feedback control of the throttle opening of the internal combustion engine to suppress excessive slip of the driving wheels, the initial throttle opening is equal to the driving wheel edge torque and the surplus torque. Since the drive wheel torque is determined based on the drive wheel effective torque determined from the above, the drive wheel torque can be rapidly converged to the optimum value, and its transient response can be improved. In particular, in a system that performs a fuel cut to suppress the drive wheel torque when the drive wheel slip rate is large, and then shifts to throttle opening control after the slip rate becomes small, from fuel cut to throttle opening control, It becomes possible to smoothly change the drive wheel torque when shifting to control. Furthermore, the crankshaft torque calculated from the operating state of the internal combustion engine is filtered, and the result is multiplied by the transmission transmission efficiency and gear ratio to obtain the drive wheel torque. The time delay error until the crankshaft torque changes is absorbed, making it possible to accurately determine the drive wheel torque.

[Brief explanation of drawings]

Fig. 1 is a complaint correspondence diagram of the present invention, Fig. 2 is a schematic configuration diagram of a vehicle equipped with this control device, Fig. 3 is a block diagram showing the electronic control unit, and Fig. 4 is the content of control in the electronic control unit. 5 is a flowchart showing the subroutine of step S3, FIG. 6 is a flowchart showing the subroutine of step S25, and FIG. 7 is a graph for determining the driving wheel effective torque. ], 01... Drive wheel edge torque calculation means, 102...
- Surplus torque calculation means, 103... Drive wheel effective torque calculation means, 104... Initial throttle opening calculation means,
9... Throttle valve, 10... Fuel cut means E... Internal combustion engine, U... Electronic control unit (drive wheel torque reduction means), Wr... Drive wheel

Claims (1)

[Claims] [1] When excessive slip of the drive wheels (Wr) is detected,
A driving wheel torque reducing means (U) that suppresses the excessive slip by feedback controlling the opening degree of a throttle valve (9) of an internal combustion engine (E) connected to the driving wheel (Wr). In the control device, the driving wheel torque reduction means (U) includes means (101) for determining the total torque of the driving wheels and means (102) for determining surplus torque consumed by excessive slip of the driving wheels (Wr).
), means (103) for determining the effective torque of the driving wheels from the total torque and surplus torque, and means (104) for determining the initial throttle opening when controlling the throttle valve (9) to close from the effective torque. A drive wheel torque control device comprising: [2] The drive wheel torque control device according to claim [1], wherein the surplus torque is determined from a drive wheel slip change rate. [3] The drive wheel torque control device according to claim 1 or [2], wherein the effective torque is obtained by linear approximation from the total torque and the drive wheel slip change rate. [4] The drive wheel torque control device further controls the drive wheel (Wr
) comprises a means (10) for cutting the fuel when excessive slip is large, and the initial throttle opening is determined when the fuel is restored from the fuel cut state.
] The drive wheel torque control device described in the above. [5] The driving wheel torque control device according to claim 4, wherein the effective torque is determined from a maximum total torque and a maximum surplus torque of the driving wheels within a predetermined time from the start of fuel cut. [6] The means (101) for determining the total torque of the drive wheels includes means for calculating crankshaft torque from the engine operating state, filtering means for filtering the calculated crankshaft torque, and filtering means for filtering the calculated crankshaft torque. The drive wheel torque control device according to claim 1, comprising means for multiplying a gear ratio and transmission transmission efficiency.