JPH02163434A - Control of engine output of vehicle - Google Patents

Abstract

PURPOSE:To permit the disposal for the variation of the atmospheric pressure by the correction of an aimed fuel injection quantity by converting the aimed engine output to an aimed fuel injection quantity and calculating the corresponding aimed throttle opening degree and controlling the throttle opening degree. CONSTITUTION:A calculation part 503 calculates the engine torque Te by correcting the axle torque Tphi according to the cooling water temperature, Tphia, and an atmo sphere correction value Tea is added to the calculation value, and a calculation part 507 calculates the corresponding aimed fuel injection quantity Fv through a lower limit value setting part 506. Then, intake air temperature correction is performed in a correction part 508, and the aimed equivalent throttle opening degree theta b is calcu lated in a calculation part 509, and the correction for the bypass opening degree DELTAtheta1 is performed, and the calculation part calculates an aimed throttle opening degree theta2. Further, a PID control part 514 outputs the opening degree correction value DELTAtheta2 corresponding to DELTAF according to the difference DELTAF between the aimed fuel injection quantity Fo and the fuel injection quantity F which is calculated on the basis of the intake air quantity obtained by a flow meter, and said correction quantity is added to theta2. Thus, the engine output can be controlled to an aimed value with high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for controlling the engine output of a vehicle when the engine output of the vehicle is set to a target engine output.

(Prior Art) Acceleration slip prevention devices (traction control devices) have been known that prevent slips of drive wheels that occur when a vehicle is suddenly accelerated. In such a traction control device, when acceleration slip of the drive wheels is detected, the slip rate S is controlled so that the coefficient of friction μ between the tire and the road surface is within the maximum range (the shaded range in Figure 18). . Here, the slip rate S is [(VP −V
B)/VP]X100 (percent), where VP is the wheel speed of the driving wheels and VB is the vehicle body speed.

In other words, when a slip of the drive wheels is detected, the engine output is controlled so that the slip ratio S falls within the shaded range, and the friction coefficient μ between the tires and the road surface is controlled within the maximum range. It prevents the drive wheels from slipping during acceleration, improving the vehicle's acceleration performance.

(Problem to be solved by the invention) In such a Traxidin control device,
When a slip of the driving wheels is detected, it is required to control the engine output to a target engine output at which no slip occurs.

The present invention has been made in view of the above points, and an object of the present invention is to provide a method for controlling engine output of a vehicle that can accurately control engine output to a target engine output.

[Structure of the Invention] (Means and effects for solving the problem) In a vehicle engine output control method for controlling a throttle opening so that the engine output of the vehicle becomes a target engine output, the target engine output is controlled by target fuel injection. target throttle opening calculation means for calculating a target throttle opening corresponding to the target fuel injection amount converted by the target fuel injection amount converting means; This is a vehicle engine output control method in which the throttle opening is controlled so that the throttle opening is the same as the opening.

(Embodiment) Hereinafter, an acceleration slip prevention device for a vehicle according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an acceleration slip prevention device for a vehicle. The figure shows a front-wheel drive vehicle, and WPR is the front right wheel,
WPL is the front left wheel, WRR is the rear right wheel, WRL
indicates the rear left wheel. Also, 11 is the wheel speed VPI of the front right wheel (drive wheel) WFR? 12 is a wheel speed sensor that detects the wheel speed VPL of the front left wheel (driving wheel) WPL; 13 is a wheel speed sensor that detects the wheel speed VRR of the rear right wheel (driven wheel) WRR; 14 is a wheel speed sensor that detects the wheel speed VRL of the rear left wheel (driven wheel) WRL. Wheel speed VFR detected by the wheel speed sensors 11 to 14
, VFL, VRR, VRIjt are input to the track/a controller 15. This traction controller 15 includes an intake air temperature detected by an intake air temperature sensor (not shown), an atmospheric pressure detected by an atmospheric pressure sensor (not shown),
Engine rotation speed N detected by a rotation sensor (not shown)
e, fuel injection ff1F per cycle calculated by a fuel control system (not shown) is input. The traction controller 15 sends a control signal to the engine 16 to perform control to prevent the drive wheels from slipping during acceleration.

As shown in FIG. 1(A), this engine 16 operates in addition to a main throttle valve THa whose opening degree θl is controlled by an accelerator pedal. It has a sub-throttle valve THs which is controlled by e2. The opening e2 of this sub-throttle valve THs is determined by the traction controller 15.
This is done by the motor drive circuit 52 controlling the rotation of the motor 52g1 based on the opening degree signal θS from. The driving force of the engine 16 is controlled by controlling the opening e2 of the sub-throttle valve THa in this manner. In addition, the above main throttle valve T Hl % sub-throttle valve T
The opening degree of Hs is determined by the throttle position sensor TP.
Detected by SI and TPS2. Furthermore, a bypass passage 52 is provided between the upstream and downstream sides of the main and sub-throttle valves THm and THs to ensure an intake air amount during idling.
b is provided, and the opening amount of this bypass passage 52b is controlled by a stepper motor 52s.

Further, 17 is a wheel cylinder that brakes the front right wheel WFR, and 18 is a wheel cylinder that brakes the front left wheel WFL. Normally, these wheel cylinders are activated by operating a brake pedal (not shown).
Pressure oil is supplied via a mask cylinder or the like (not shown). When traction control is activated, pressure oil can be supplied from another route as described below. Pressure oil is supplied from the hydraulic source 19 to the wheel cylinder 17 through an inlet valve 17i, and pressure oil is discharged from the wheel cylinder 17 to the reservoir 20 through an outlet valve 17o.

Further, pressure oil is supplied from the hydraulic source 19 to the wheel cylinder 18 via an inlet valve 18i,
Pressure oil is discharged from the wheel cylinder 18 to the reservoir 20 via an outlet valve 18o. Opening/closing control of the inlet valves 17i and 1811 and the outlet valves 17o and 18o is performed by the traction controller 15.

Next, the detailed configuration of the traction controller 15 will be described with reference to FIGS. 2(A) and 2(B).

The wheel speeds VFR and VI'L of the driving wheels detected by the wheel speed sensors 11 and 12 are determined by the high vehicle speed selection section (SH).
31 and the wheel speed V! -'R and wheel speed VPL
The one with the higher wheel speed is selected and output. At the same time, the wheel speeds VFR and VPL of the driving wheels detected by the vehicle speed sensors 11 and 12 are averaged in an averaging section 32 to obtain an average wheel speed (VFR+VFL)/
2 is calculated.

The wheel speed output from the high vehicle speed selection section 31 is weighted and multiplied by a variable KO in a section 33, and the average wheel speed output from the averaging section 32 is weighted and multiplied by a variable (1-KO) in a section 34. They are each sent to an adding section 35 and added to form the driving wheel speed VP. Note that the variable KG is a variable that changes depending on the centripetal acceleration GY, as shown in FIG.

As shown in FIG. 3, it is set so that the centripetal acceleration GY is proportional to the centripetal acceleration until it reaches a predetermined value (for example, 0.1 g), and then becomes "1" when it reaches "2".

Further, the wheel speeds of the driven wheels detected by the wheel speed sensors 13 and 14 are input to a low vehicle speed selection section 36, and the smaller wheel speed is selected. Further, the wheel speeds of the driven wheels detected by the wheel speed sensors 13 and 14 are input to the high vehicle speed selection section 37, and the larger wheel speed is selected. The smaller wheel speed selected by the low vehicle speed selection section 36 is weighted by a variable Kr in section 38, and the larger wheel speed selected by the high vehicle speed selection section 37 is weighted by section 39. , the variable is multiplied by (1-Kr). This variable is defined as the centripetal acceleration GY as shown in Figure 4.
It changes between "1" and "0" depending on the time.

Further, the wheel speeds output from the weighting unit 38 and the weighting unit 39 are added in an adding unit 40 to obtain the driven wheel speed VR, and further, the driven wheel speed VR is calculated in the multiplication unit 40' as ( 1+α) and set as the target driving wheel speed VΦ.

Then, the driving wheel speed VF output from the adding section 35
and "target drive wheel speed V output from the bipedal multiplier 40'
Φ is subtracted by the subtraction unit 41 and the slip mDVL'
(-VP-VΦ) is calculated. This slip fa
DVi' is further added to the centripetal acceleration G in the addition section 42.
The slip ff1DVi' is corrected according to the rate of change ΔGY of Y and the centripetal acceleration GY. That is, the slip amount correction section 43 is set with a slip correction ffiVg that changes according to the centripetal acceleration GY as shown in FIG. 5, and the slip amount correction section 44 is set with the centripetal acceleration GY as shown in FIG. A slip correction ff1Vd is set that changes according to the rate of change ΔGY. Then, in the adding section 42, the slip corrections JIVd and Vg are added to the slip mDvi' outputted from the subtracting section 41 to obtain the slip ff1DVi.

This slip mDVi is sent to the calculation section 45a in the TSn calculation section 45 at a sampling time T of, for example, 151 seconds, and the slip ff1DVL is integrated while being multiplied by a coefficient Kl to obtain the correction torque TSn'. That is, the correction torque obtained by correcting the slip ff1DVi, that is, the integral correction torque TSn' is obtained as TSn'-ΣKI DVt (Kl is a coefficient that changes depending on the slip amount DVi). The integral correction torque TSn' is a correction value for the torque that drives the driving wheels WFR and WPL, and is a correction value for the torque that drives the driving wheels WFR and WPL, and is based on the fact that the characteristics of the power transmission mechanism between the engine 16 and the driving wheels change due to changing gears. Since it is necessary to adjust the control gain according to
In b, the integral correction torque TS is multiplied by a coefficient GK1 that differs depending on the gear position and corrected according to the gear position.
n is calculated.

Furthermore, the above slip ff1DVi is the sampling time T
Each time, the correction torque TPn' is sent to the calculation section 46a of the TPn calculation section 46 and corrected by the slip amount DVi. In other words, the corrected torque corrected by the slip jaDVL as TPn' - DV i #Kp (Kp is a coefficient),
In other words, the proportional correction torque TPn' is obtained. Then, the proportional correction torque TPn is multiplied by a different coefficient GKp depending on the gear position in the coefficient multiplier 46b for the same reason as the integral correction torque Tsn', and the proportional correction torque TPn after correction according to the gear position is obtained. Calculated.

Further, the driven wheel speed VR output from the addition section 40 is inputted to the reference torque calculation section 47 as the vehicle body speed VB. Then, in the vehicle body acceleration calculation section 47a within this reference torque calculation section 47, the acceleration VB (GB) of the vehicle body speed is calculated.

Then, the vehicle body acceleration VB (GB) calculated by the vehicle body acceleration calculating section 47a is passed through a filter 47b and is made into a vehicle body acceleration GBF. In this filter 47b, in order to quickly shift from the state of the "1" position shown in FIG. 15 to the state of the "2" position when acceleration increases, the GBPI t which is the output of the previous filter 47b and the currently detected GB , and are averaged with the same weighting, GBPll - (GB n + GBPn 1 ) /
2-(1). Also, the slip rate S>Sl
(Sl is set to a value slightly smaller than the maximum slip rate Ssax) and when the acceleration decreases, for example, "2"
When moving from the position to the "3" position, the filter 47b is switched to a slow filter in order to move slowly. In other words, GBPn = (GI3 n + 7 GBFn i
)/8-(2), the previous output of the filter 47b is weighted.

In addition, when the slip rate S≦81 and the acceleration decreases, that is, “1
When acceleration decreases in the region of
Since we want to stay at X, filter 47b is switched to a slower filter. In other words, GBPn = (GB n + 1
5GBFnl)/te
--(3), a great deal of weight is placed on the output of the previous filter 47b. In this way, the filter 47
In b, the filter 47b is switched in three stages as shown in equations (1) to (3) above depending on the state of acceleration. Then, the vehicle body acceleration GBF is sent to a reference torque calculation section 47c, where a reference torque TG is calculated. That is, TG=GBPXWXRe is calculated. Here, W is the vehicle weight and Re is the tire radius.

Then, the reference torque TO and the integral correction torque T
Subtraction with Sn is performed in a subtraction unit 48, and further subtraction with the proportional correction torque TPn is performed in a subtraction unit 49. In this way, the target torque TΦ is calculated as TΦ-TG-TSn-TPn.

This target torque TΦ indicates the axle torque that drives the driving wheels WFR and WFL. This axle torque TΦ is manually inputted to the addition unit 501 via a switch S1 opened and closed by a start/end determination unit 50 that determines the start/end of traction control, and is inputted to an adding unit 501 by factors that influence the relationship between the axle torque TΦ and engine torque, such as The axle torque is corrected for the coolant temperature of the engine 16. This correction is TΦ
This is performed by adding the correction ITΦa from the correction unit 502. Then, the corrected axle torque TΦl output from the adding section 501 is calculated by the engine torque calculating section 503.
In , the target engine torque To is divided by the total gear ratio between the engine 16 and the drive shaft. To this target engine torque Ta, an addition section 504 adds a correction m T ea of the target engine torque Te resulting from atmospheric conditions etc. from a To correction section 505 . The target engine torque Tel corrected in this way is determined by the lower limit value setting section 50 that sets the lower limit value T11m of the engine torque.
6, as shown in FIG. 16 or FIG. 17, the value is limited to a value equal to or higher than a lower limit value T111 that changes depending on the elapsed time t from the start of traction control or the vehicle speed VB. Then, the target engine torque Tel, which is limited to a value equal to or higher than the lower limit value Tlfi of the engine torque by the lower limit value setting unit 51, is sent to the target fuel injection amount calculation unit 507, and the target fuel injection for outputting the target engine torque Tel is sent to the target fuel injection amount calculation unit 507. mFt is calculated. The target fuel injection amount calculation unit 507 calculates the target fuel injection mFt from the engine rotational speed Ne and the target engine torque Tel by referring to the three-dimensional map shown in FIG. That is, it is calculated as FL −f [Ne, Te1l.

Here, Ft is the fuel injection amount per injection, f [No,
The telephone number is the engine rotation speed No. and the target torque Te.
This is a three-dimensional map with l as a parameter.

Note that Ft may be a product of the engine rotational speed NO by a coefficient Ka and the target torque Tel as shown in FIG. 21, that is, Ft - Ka (Ne) * Tel. Furthermore, Ka(No) may be a constant.

Further, in the target fuel injection amount calculation unit 507, the fuel injection amount ff1Ft is corrected by the intake air temperature and atmospheric pressure and converted into the fuel injection amount Fv under standard atmospheric conditions.

In other words, Fv - Ft/1Kt (AT) * Kp (AT) 1. Here, KL is the density correction coefficient using the intake air temperature (AT) as a parameter as shown in Figure 22, and Kp is the density correction coefficient using the atmospheric pressure (AT) as a parameter as shown in Figure 23. It shows.

The target fuel injection amount m F v calculated in this way is corrected by the intake air temperature in the target fuel injection amount correction section 508, and is set as the target fuel injection amount FO.

In other words, F.O. =Fv*Ka’ (AT) It is said that

Here, FO is the target fuel injection amount after correction, Fv is the target fuel injection amount before correction, and Ka' is a correction coefficient based on the intake air temperature (AT).

Hereinafter, the target fuel injection jllFO output from the target fuel injection amount correction section 508 is determined by the equivalent target throttle opening calculation section 5.
09, the equivalent target throttle opening degree θb for the engine rotational speed Ne and the target fuel injection amount FO is determined by referring to the map shown in FIG. This equivalent target throttle opening θb is the throttle valve opening for achieving the target fuel injection ff1FO when there is one throttle valve. Further, if there is a bypass passage 52b that bypasses the sub-throttle valve THs, the equivalent target throttle opening eb is subtracted from the equivalent target throttle opening θb by the opening corresponding to the amount of air passing through the bypass passage 52b. . That is, in the subtraction unit 510, the opening degree Δθl corresponding to the amount of air passing through the exhaust passage is subtracted from the equivalent target throttle opening degree eb.

Hereinafter, the above (θb - Δ6) 1) is sent to the target throttle/sottle opening calculation unit 512 to calculate the sub throttle valve THs when the throttle opening of the main throttle valve TH+e is 01.
A target throttle opening degree θ2 is calculated.

In this way, if the fuel injection mFt per cycle is determined, the amount of intake air taken into the engine can be calculated,
Furthermore, the target throttle opening e2 of the sub-throttle valve THs is determined from this intake air amount. The reason why the target throttle opening e2 can be determined if the fuel injection amount F per cycle is known in this manner will be described below. In other words, the amount of intake air taken into the engine via the secondary main throttle valve THa (auxiliary throttle valve THs) and the bypass passage 52b is detected by an air flow sensor (not shown) provided in the air cleaner. The detected intake air amount is sent to the fuel control system to determine the fuel injection amount Ft per cycle. In other words, in the fuel control system, the fuel injection amount per cycle F is calculated from the intake air amount.
t is being calculated. Therefore, if the fuel injection mFt per cycle is known, the amount of intake air taken into the engine at that time can be calculated backwards. Once this amount of intake air is known, the target throttle opening e2 of the sub-throttle valve THs can be determined by considering the amount of air passing through the bypass passage 52b and the opening of the main throttle valve TH11. Therefore, in this embodiment, the fuel injection EkFt per cycle required to obtain the target engine torque Tel is calculated, and the sub-throttle valve THs is adjusted while making various corrections.
By determining the target throttle opening e2, highly accurate engine output control is realized.

By the way, the corrected target fuel injection amount FO outputted from the target fuel injection amount correction section 508 is sent to the subtraction section 513, and the fuel injection amount FO is sent to the subtraction section 513, and the fuel injection amount is calculated at every predetermined sampling time based on the intake air amount of the engine detected by the air flow sensor. A difference ΔF from the current fuel injection amount F calculated by the control system is calculated. This ΔF is sent to the PID control unit 514, and ΔF is
PID control is performed on F, and an opening correction amount Δθ2 corresponding to ΔF is calculated. This opening correction amount Δe is added to the target throttle opening e2 in an adding section 51 to calculate a feedback-corrected target opening er. In other words, θr-02+Δθ2. Here, the opening correction amount Δθ is the opening correction amount Δθp1 based on proportional control, and the opening correction amount Δθ1 based on integral control.
, the opening degree correction amount Δθd by differential control is added. In other words, Δe−Δθp+Δθ1+Δθd.

Here, Δep ” Kp (No) * Kth (Ne) *
ΔFΔe I −K 1 (No) * K th
(Ne) * Σ (ΔF)Δθd −Kd(Ne
) zero Kth(Ne) (calculated in the PID$i control unit 514 as ΔF-ΔFoldl. Here, Kp, Kl, and 9 are engine rotation speed Ne
These are proportional, integral, and differential gains with parameters as parameters, and their characteristic diagrams are shown in FIGS. 26 to 28. Also,
Kth is ΔF- with engine speed No. as a parameter
Δθ food exchange gain (Figure 29), ΔF is target fuel injection amount F
The deviation between O and the fuel injection ff1F calculated by the fuel control system, ΔF Old, is ΔF at the previous sampling timing.

The target opening degree er obtained as described above is sent to the motor drive circuit 52 as the sub-throttle valve opening signal θS, and the opening degree of the sub-throttle valve THs is controlled.

Further, the wheel speeds VRR and VRL of the driven wheels are sent to the centripetal acceleration calculating section 53, and the centripetal acceleration GY' is calculated in order to determine the degree of turning. This centripetal acceleration GY' is sent to the centripetal acceleration correction section 54, and the centripetal acceleration GY' is corrected according to the vehicle speed.

That is, GY-Kv-GY'l is calculated, and the coefficient Kv changes according to the vehicle speed as shown in FIGS. 7 to 12, so that the centripetal acceleration GY is corrected according to the vehicle speed.

Incidentally, the higher driven wheel speed output from the high vehicle speed selection section 37 is subtracted from the wheel speed VFR of the driving wheels in the subtraction section 55. Further, the higher driven wheel speed output from the high vehicle speed selection section 37 is subtracted from the driving wheel speed VPL in a subtraction section 56.

The output of the subtraction unit 55 is multiplied by KB (Q
<KB<1), and the output of the subtraction section 56 is outputted to the multiplication section 58.
After being multiplied by (1-KB) in the adding section 59, the slip mDVPR of the right drive wheel is obtained.

At the same time, the output of the subtraction section 56 is multiplied by K8 in a multiplication section 60, and the output of the subtraction section 55 is multiplied by (1-KB) in a multiplication section 61, and then added in an addition section 62. The slip EIDVFL is assumed to be EIDVFL.

As shown in Fig. 13, the variable KB changes according to the elapsed time from the start of traction control, and when the traction control starts, rO
, 5J, and is set to approach rO, 8J as the traction control progresses.

For example, when KB is set to rO, 8J, when slip occurs in only one drive wheel, the brake control is performed by recognizing that slip has occurred in the other drive wheel by 20% of that of the other drive wheel. I have to. This is because if the brakes on the left and right drive wheels are completely independent, when only one drive wheel is braked and its rotation is reduced, the action of the differential will cause the opposite drive wheel to slip and apply the brakes. This is because it is repeated and is not desirable.

The slip amount D V PR of the right drive wheel is determined by the differential section 63.
The slip amount DVFL of the left driving wheel is differentiated in the differentiator 64 to calculate the amount of change over time, that is, the slip acceleration GPR, and the slip amount DVFL of the left driving wheel is differentiated in the differentiator 64 to calculate the amount of change over time, that is, the slip acceleration GPL. . Then, the slip acceleration GPR is sent to the brake branch pressure change amount (ΔP) calculating section 65, and the GPR (G FL) - ΔP conversion map shown in FIG. 14 is referred to to obtain the slip acceleration CFI? The amount of change ΔP in brake fluid pressure for suppressing this is determined. This amount of change in brake fluid pressure Δ
P is sent to the ΔP-T conversion section via the switch S2 whose opening/closing is controlled by the start/end determination section 50, and the opening time T of the inlet valve 171 in FIG. 1(A) is calculated.

Similarly, the slip acceleration GPL is a change in brake fluid pressure! (ΔP) is sent to the W peak part 66 and the G shown in FIG.
The PR(GPL)-ΔP conversion map is referred to to determine the amount of change ΔP in brake fluid pressure for suppressing slip acceleration GPL. This amount of change in brake fluid pressure ΔP
is sent to the ΔP-T conversion unit 68 via the switch S3 whose opening/closing is controlled by the start/end determination unit 50, and the open time T of the inlet valve 181 in FIG. 1(A) is calculated.

Note that the switches S1 to S3 are opened and closed in conjunction with each other.

In addition, in Fig. 14, when applying the brakes when turning, in order to strengthen the brakes on the inner drive wheels,
The inner wheel side when turning is shown by a broken line a.

Next, the operation of the present invention configured as described above will be explained. In FIGS. 1 and 2, wheel speed sensor 1
The wheel speed of the driven wheel (rear wheel) output from 3.14 is determined by the high vehicle speed selection section 36. Low vehicle speed selection section 37. It is input to the centripetal acceleration calculation section 53.

In the low vehicle speed selection section 36, the smaller wheel speed of the left and right driven wheels is selected, and the high vehicle speed selection section 37
In , the wheel speed of the larger one of the left and right driven wheels is selected. When the wheel speeds of the left and right driven wheels are the same during normal straight-line driving, the low vehicle speed selection section 3
The same wheel speed is selected from 6 and the high vehicle speed selection section 37. In addition, the wheel speeds of the left and right driven wheels are input to the centripetal acceleration calculation unit 53, and the turning angle when the vehicle is turning, that is, how steep the turn is, is determined from the wheel speeds of the left and right driven wheels. The degree to which the

Hereinafter, how the centripetal acceleration is calculated in the centripetal acceleration calculating section 53 will be explained.

In a front-wheel drive vehicle, since the rear wheels are driven wheels, the vehicle speed at that position can be detected by the wheel speed sensor regardless of slip caused by the drive, so Ackermann geometry can be used. In other words, in a steady turn, the centripetal acceleration GY' is GY'-v2/r
...(4) Calculated as (V - vehicle speed, - turning radius).

For example, when the vehicle is turning to the right as shown in FIG. 19, the center of turning is Mo, and the center of turning MO
If the distance from to the inner wheel (WRR) is l, the tread is Δr, the wheel speed of the inner wheel (WI?R) is vl, and the wheel speed of the outer wheel (WRL) is v2, then v2/ vl-(Δr+rL)/rl...(5
).

Then, by transforming the above equation (5), 1/rl = (v2-vl)/Δr・vl =
16). Then, the claimed center acceleration GY' characterized by the inner ring side is GY'5=vL2/rl-vl2(v2-vl)/Δr*v
l-vl (v2-vl)/Δr-(7
) is calculated as

That is, the centripetal acceleration GY' is calculated using the seventh equation.

By the way, when turning, the inner wheel speed v1 is smaller than the outer wheel speed v2, so the inner wheel speed vl is used to calculate the centripetal acceleration GY', so the centripetal acceleration GY' is calculated to be smaller than the actual one. be done. Therefore, the coefficient KG multiplied by the weighting section 33 is estimated to be small because the centripetal acceleration GY' is estimated to be small. Therefore,
Since the drive wheel speed vF is estimated to be small, the slip ff1DV' (VP-VΦ) is also estimated to be small. As a result, since the target torque TΦ is estimated to be large, the target engine torque is also estimated to be large, thereby providing sufficient driving force even when turning.

By the way, at extremely low speeds, the distance from the inner wheels to the turning center MO is rl, as shown in Figure 19, but in a vehicle that understeers as the speed increases, the turning center is at M. The distance is r(r>r
l).

Even if the speed increases in this way, since the turning radius is calculated as ``l'', the centripetal acceleration GY' calculated based on the above formula 7 will be calculated as a larger value than the actual value. The centripetal acceleration GY′ calculated in the centripetal acceleration calculation unit 53 is sent to the centripetal acceleration correction unit 54, so that the centripetal acceleration GY becomes smaller at high speeds.
The centripetal acceleration GY' is multiplied by the coefficient Kv shown in FIG. This variable Kv is set to decrease according to the vehicle speed, and may be set as shown in FIG. 8 or 9. In this way, the centripetal acceleration correction unit 54 outputs the corrected centripetal acceleration GY.

On the other hand, as the speed increases, oversteer occurs (r<
rl) In the vehicle, the centripetal acceleration correction unit 54 performs a correction that is completely opposite to that of the understeering vehicle described above. That is, one of the variables Kv shown in FIGS. 10 to 12 is used to correct the centripetal acceleration GY' calculated by the centripetal acceleration calculating section 53 so that it increases as the vehicle speed increases.

By the way, the smaller wheel speed selected in the low vehicle speed selection section 36 is multiplied by a variable in the weight section 38 as shown in FIG. 4, and the high vehicle speed selected in the high vehicle speed selection section 37 is weighted. is the variable (1-Kr
) will be multiplied. For example, if the centripetal acceleration GY is 0.9
It is set to "1" when the turning becomes larger than g, and becomes "0" when the centripetal acceleration GY becomes smaller than 0.4 g.
is set to

Therefore, for a turn in which the centripetal acceleration GY is greater than 0.9 g, the wheel speed of the lower vehicle speed among the driven wheels output from the low vehicle speed selection section 36, that is, the wheel speed of the inner wheel at the time of selection is selected. be done.

Then, the weighting is performed by adding the wheel speeds output from sections 38 and 39 in an adding section 40 to obtain the driven wheel speed VR.
Further, the driven wheel speed VR is multiplied by (1+α) in a multiplier 40' to obtain the target driving wheel speed VΦ.

Further, after the higher wheel speed of the drive wheels is selected in the high vehicle speed selection section 31, weighting is performed in the section 33.
In this case, the variable KG is multiplied as shown in FIG. Furthermore, the average vehicle speed (V
FR+VFL)/2 is weighted in section 34,
(1-KG), and the above-mentioned weighting is added to the output of the section 33 and the adding section 35 to obtain the driving wheel speed VF. Therefore, when the centripetal acceleration GY becomes, for example, 0.1 g or more,
KG-1, the wheel speed of the larger of the two drive wheels output from the high vehicle speed selection section 31 is output. In other words, when the turning angle of the vehicle increases and the centripetal acceleration GY becomes, for example, 0.9 g or more,
In order to obtain rKG-Kr-IJ, on the driving wheel side, the wheel speed of the outer wheel side with a higher wheel speed is set as the driving wheel speed VF, and on the driven wheel side, the wheel speed of the inner wheel side with a lower wheel speed is set as the driven wheel speed VR. Therefore, the slip amount DVi' (=VF-VΦ) calculated by the subtraction unit 41 is estimated to be large. Therefore, in order to estimate the target torque TΦ to be small, the engine output is reduced, the slip ratio S is reduced, and the lateral force A can be increased as shown in FIG. can be raised to make a safe turn.

The slip amount DVi' is calculated by the slip amount correction section '43.
, a slip correction amount vg as shown in FIG. 5 is added only when turning when centripetal acceleration GY occurs, and
In the slip amount correction section 44, a slip EIVd as shown in FIG. 6 is added.

For example, if we assume a turn at a right angle,
In the first half of the turn, the centripetal acceleration GY and its rate of change over time ΔGY take positive values, but in the second half of the curve, the rate of change GY of the centripetal acceleration GY over time ΔGY takes a negative value. Therefore, in the first half of the curve, the adder 42 has a slip ff1DVi.
', the slip correction amount Vg (>0) shown in Fig. 5 and the slip correction ff1Vd (>0) shown in Fig. 6 are added to form the slip amount DVi, and in the latter half of the curve, the slip correction amount Vg (>0) is added. ) and slip correction amount va c
<o> is added to obtain the slip amount DV1. Therefore, by estimating the slip amount DVi in the second half of the turn to be smaller than the slip amount DVi in the first half of the turn, engine output is reduced and lateral force is increased in the first half of the turn, and the second half of the turn is made smaller than the first half. It restores engine output and improves vehicle acceleration.

In this way, the corrected slip faDVi is sent to the TSn calculation section 45 with a sampling time T of, for example, 15 rinS. In this TSn calculating section 45, the slip amount DVL is multiplied by a coefficient KI and integrated to obtain a correction torque TSn.

In other words, TSn-GKiΣKl-DVI (Kl is slip f
The correction torque obtained by correcting the slip amount DVi, that is, the integral correction torque TSn is obtained as a coefficient that changes according to f1DVl.

Moreover, the above slip ff1DV1 is the sampling time T
Each time, the correction torque TPn is sent to the TPn calculation unit 46 and the correction torque TPn is calculated. In other words, TPn −GKp DVi −Kp (Kp is the coefficient)
The correction torque corrected by the slip EIDVI, that is, the proportional correction torque TPn is determined as follows.

Furthermore, the values of the coefficients GKi and GKp used in the calculations in the coefficient multipliers 45b and 46b are switched to values corresponding to the gear position after the shift after a set time from the start of the shift during upshifting. This is because it takes time from the start of the shift until the gear is actually changed and the shift is completed, and when the shift is started, the above-mentioned gear corresponding to the high gear after the shift is started.

Using the numbers GKI and GKp, the above correction torque TSn
, the value of TPn becomes a value corresponding to the above-mentioned high speed gear, so even though the actual shift has not finished, it becomes smaller than the value before the start of the shift, and the target torque TΦ becomes large, inducing slip and control. This is because it becomes unstable.

Further, the driven wheel speed VR output from the addition section 40 is inputted to the reference torque calculation section 47 as the vehicle body speed VB. Then, the vehicle body acceleration calculating section 47a calculates the acceleration VB (GB) of the vehicle body speed. Then, the acceleration CB of the vehicle body speed calculated by the vehicle body acceleration calculating section 47a is filtered by any one of formulas (1) to (3) by the filter 47b as explained in the configuration section, and the acceleration CB is The GBP is kept at an optimal position depending on the state of the vehicle. Then, in the reference torque calculation unit 47c, the reference torque TG (=GBPx
WxRe) is calculated.

The reference torque TG and the integral correction torque T
Subtraction with Sn is performed in a subtraction unit 48, and the proportional correction torque TPn is further subtracted in a subtraction unit 49. In this way, the target torque TΦ is calculated as TΦ-TG-TSn-TPn.

This target torque TΦ, that is, the axle torque TΦ, is input to the adding section 501 via the switch S1, and the axle torque TΦ is corrected, for example, with respect to the cooling water temperature of the engine 16, and is set to TΦl. Then, the corrected axle torque TΦl output from the adding section 501 is converted into a target engine torque TO in the engine torque calculating section 503. To this target engine torque To, a correction m''rea of the target engine torque Te due to atmospheric conditions etc. is added in an adding unit 504.The target engine torque Tel thus corrected is the lower limit value T1 of the engine torque.
In the lower limit value setting unit 506 which sets 1-, the lower limit value of the target engine torque Tel is limited. and,
This target engine torque Tel is sent to a target fuel injection amount calculation unit 507, and a target fuel injection amount Ft for outputting the target engine torque Tel is calculated.

Further, in the target fuel injection amount calculating section 507, the fuel injection amount Ft is corrected based on the intake air temperature and atmospheric pressure, and is converted into the fuel injection amount Fv under standard atmospheric conditions.

In this way, the calculated target fuel injection m F v is corrected by the intake air temperature in the target fuel injection amount correction section 508, and is set as the target fuel injection ff1FO.

Thereafter, the target fuel injection amount FO output from the target air amount correction section 508 is sent to the equivalent target throttle opening calculation section 509, and the map in FIG. A target throttle opening degree eb is determined. Then, in the subtraction unit 510, an opening degree ΔF corresponding to the amount of air passing through the bypass passage 52b is subtracted from the equivalent target throttle opening degree eb.

Hereinafter, the above (θb-Δe1) is sent to the target throttle opening calculation unit 512, and the target throttle opening e2 of the sub throttle valve THs when the throttle opening of the main throttle valve TH■ is 01 is calculated.

By the way, the corrected target fuel injection jlFO outputted from the target fuel injection amount correction section 508 is sent to a subtraction section 513, and the fuel is controlled at every predetermined sampling time based on the intake air amount of the engine detected by the air flow sensor. The difference ΔF from the current fuel injection amount F calculated by the system is calculated. This ΔF is sent to the PID control unit 514,
PID control is performed based on ΔF, and an opening degree correction amount Δθ2 corresponding to ΔF is calculated. This opening correction amount Δθ2 is added to the target throttle opening e2 in an adding section 51 to calculate a feedback-corrected target opening θr.

The target opening e'' obtained as described above is sent to the motor drive circuit 52 as the sub-throttle valve opening signal es, and the opening of the sub-throttle valve THs is controlled.

Incidentally, the higher driven wheel speed output from the high vehicle speed selection section 37 is subtracted from the wheel speed VFR of the driving wheels in the subtraction section 55. Further, the higher driven wheel speed output from the high vehicle speed selection section 37 is subtracted from the driving wheel speed VPL in a subtraction section 56.

Therefore, the outputs of the subtraction units 55 and 56 are estimated to be small to reduce the number of times the brake is used even during turning, and the slip of the driving wheels is reduced by reducing the engine torque.

The output of the subtraction unit 55 is multiplied by 8 (0) in the multiplication unit 57.
<KB<1), and the output of the subtraction section 56 is outputted to the multiplication section 58.
After being multiplied by (1-KB) in the adding section 59, it is added to the slip amount DVFR of the right drive wheel.

At the same time, the output of the subtraction section 56 is multiplied by KB in a multiplication section 60, and the output of the subtraction section 55 is multiplied by (1-KB) in a multiplication section 61, and then added in an addition section 62 to produce the output of the left driving wheel. The amount of slip is DVFL.

As shown in Fig. 13, the variable KB changes according to the elapsed time t from the start of traction control, and when the traction control starts, r
It is set to rO, 5J, and as the traction control progresses, it approaches rO, 8J. In other words, when reducing the slip of the drive wheels by braking, it is possible to apply the brakes to both axles at the same time when braking is started, thereby reducing the unpleasant steering shock that occurs when braking is started on a split road, for example. . On the other hand, the operation when the brake control is continued and the above KB becomes rO, 8J will be described. In this case, when slip occurs in only one drive wheel, brake control is performed by recognizing that slip has occurred in the other drive wheel by 20% of that of the one drive wheel.

This is because if the brakes on the left and right drive wheels are made completely independent, only one drive wheel will be braked, and when rotation decreases, the opposite drive wheel will slip and brake due to the action of the differential, and this operation will be interrupted. This is because it is repeated and is not desirable. The slip mDVFR of the right drive wheel is differentiated in a differentiator 63 to calculate its temporal variation, that is, the slip acceleration GPR, and the slip amount DVFL of the left drive wheel is differentiated in a differentiator 64 to calculate its temporal change. Amount of change, that is, slip acceleration GPL
is calculated. Then, the slip acceleration GFR is sent to the brake fluid pressure change Jl (ΔF) calculating section 65, and the G PR (G PL) - ΔP conversion map shown in FIG. The amount of change ΔP in brake fluid pressure is determined.

Furthermore, the amount of change ΔP is ΔP used to calculate the opening time T of the inlet valve 171 when the switch S2 is opened, that is, when the start/end determining section 50 determines that the control start condition is satisfied.
−T converter 67. In other words, the valve opening time T calculated in the ΔP-T converter 67 is
The FR brake operation time is PR. Also, similarly,
The slip acceleration GPL is sent to the brake fluid pressure change amount (ΔF) calculation unit 66, and the GPR (GPL) shown in FIG.
−ΔP conversion map is referred to and slip acceleration GP
The amount of change ΔP in brake fluid pressure for suppressing L is determined. This amount of change ΔP is calculated from ΔP-
The signal is given to the T converter 68. In other words, the ΔP-T converter 6
The valve opening time T calculated in 8 is the left drive wheel WF.
The brake operation time of L is assumed to be FL. This prevents the left and right drive wheels WPR, WPL from causing more slip.

In addition, in Fig. 14, when applying the brakes when turning, in order to strengthen the brakes on the inner drive wheels,
The inner wheel side when turning is shown by a broken line a. In this way, when turning, the load shifts to the outer wheel side and the inner wheel side becomes prone to slipping. This can sometimes prevent the inner ring from slipping.

In the above embodiment, feedback control is performed by PID control based on ΔF to correct the target opening e2. The control may be performed such that the correction amount is increased by the amount of correction 602 obtained by the control.

Further, although an acceleration slip prevention device is shown as an embodiment of the present invention, the present invention is not limited to this device, and can be similarly applied to any device that controls a throttle valve.

[Effects of the Invention] As detailed above, according to the present invention, in the vehicle engine output control method of controlling the throttle opening so that the vehicle engine output becomes the target engine output, the target engine output is controlled by the target fuel injection. Since the target throttle opening degree is calculated after converting the amount into a quantity, even if the atmospheric pressure or air density changes, it can be dealt with by correcting the target fuel injection quantity, so an appropriate target throttle opening degree can be obtained. It is possible to provide a method for controlling the engine output of a vehicle.

[Brief explanation of the drawing]

FIG. 1(A) is an overall configuration diagram of an acceleration slip prevention device to which the control method according to the present invention is applied, FIG. 1(B) is a diagram showing the arrangement of the main and sub-throttle valves, and FIG. A) and (B) are block diagrams showing the control of the traction controller in Fig. 1 (A) divided into functional blocks, Fig. 3 is a diagram showing the relationship between centripetal acceleration GY and variable KG, Fig. 4 is a diagram showing the relationship between the centripetal acceleration GY and the variable Kr, Figure 5 is a diagram showing the relationship between the centripetal acceleration GY and the slip correction QVg, and Figure II6 is a diagram showing the relationship between the centripetal acceleration GY and the slip correction amount Vd. Figures 7 to 12 are diagrams showing the relationship between the vehicle speed VB and the variable Kv, and Figure 13 is a diagram showing the relationship between the vehicle speed VB and the variable Kv.
Figure 14 shows the change over time in the slip amount Q G FR (G PL) and the change amount Δ in the brake fluid pressure.
Figures 15 and 18 are diagrams showing the relationship between slip ratio S and road surface friction coefficient μ, Figure 16 is a diagram showing the characteristics of Tl1s-, and Figure 17 is a diagram showing the relationship between Tli
*-A diagram showing VB characteristics, FIG. 19 is a diagram showing the state of the vehicle during turning, FIG. 20 is a diagram showing a target engine torque-engine rotation speed map, and FIG. 21 is an engine rotation speed Ne characteristic of coefficient Ka. Figure 22 is a diagram showing the intake air temperature characteristics of the coefficient Kt, Figure 23 is a diagram showing the atmospheric pressure characteristics of the coefficient Kp, Figure 24 is a diagram showing the intake air temperature characteristics of the coefficient Ka', and Figure 25 is the target A/N-engine rotation speed map; Figure 26 is a diagram showing engine rotation speed characteristics of proportional gain Kp; Figure 27 is a diagram showing engine rotation speed characteristics of integral gain Kl; Figure 28 is differential gain. FIG. 29 is a diagram showing the engine rotation speed characteristic of Kd, and FIG. 29 is a diagram showing the engine rotation speed characteristic of conversion gain. 11-14...Wheel speed sensor, 15...Traction controller, 45...TSn calculation unit, 45b. 46b... Coefficient multiplier, 46... TPn calculation unit, 4
7... Reference torque calculation section, 503... Engine torque calculation section, 507... Target fuel injection amount calculation section, 512
. . . target throttle opening calculation unit, 53 . . . centripetal acceleration calculation unit, 54 . . . centripetal acceleration correction unit. Applicant's agent Patent attorney Takehiko Suzue (B) V Fig. Fig. Fig. Fig. 4VB Fig. Fig. Fig. Fig. 4VB Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. 4. Fig. Fig. Fig. Fig. Fig. Fig. Fig. 4) Figure 22: Atmospheric pressure, f, ffi (AT) (Ap) Go to Figure 20 Figure 20 Figure Figure 2

Claims (2)

[Claims] (1) A vehicle engine output control method for controlling a throttle opening so that the vehicle engine output becomes a target engine output, including a target fuel injection amount converting means for converting the target engine output into a target fuel injection amount; and a target throttle opening calculation means for calculating a target throttle opening corresponding to the target fuel injection amount converted by the target fuel injection amount conversion means, and the throttle opening is controlled so as to reach the target throttle opening. A vehicle engine output control method characterized by: (2) To the target throttle opening, a throttle opening correction amount corresponding to the deviation between the target fuel injection amount and the fuel injection amount calculated by the fuel control system is added to the target throttle opening correction amount. 2. The method for controlling engine output of a vehicle according to claim 1, wherein the throttle opening is controlled so that the throttle opening is equal to the throttle opening.