JP3428363B2 - Vehicle driving force control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving force control device for preventing idling of driving wheels to ensure vehicle stability and drivability, and more particularly to improvement of a driving force control device provided with a continuously variable transmission. Is.

[0002]

2. Description of the Related Art A driving force control device (or TC for preventing acceleration performance from being lowered due to idling of driving wheels during acceleration or the like)
(S = traction control system), the engine output is suppressed by reducing the opening of the second throttle driven by the actuator, fuel injection cut, ignition timing retard control, etc. BACKGROUND ART A device that suppresses idling has been conventionally known, and as a driving force control device for a vehicle equipped with a continuously variable transmission, for example, Japanese Patent Laid-Open No. 4-50440 is known.

Further, as a continuously variable transmission, a V-belt type and a toroidal type have been conventionally known, and shift control of these continuously variable transmissions is performed by detecting a detected vehicle speed (≈driving wheel speed) or a throttle opening (or). The target gear ratio is continuously changed from an operating state such as the accelerator pedal depression amount) based on a preset gear shift map.

[0004]

However, when a continuously variable transmission is combined with the above-described conventional vehicle driving force control device, when a highly responsive driving force control such as a fuel injection cut is performed, there is no The speed change response of the multi-speed transmission cannot follow the driving force control, and the speed change control device sets the ratio of the output shaft speed (≈drive wheel speed Vwr) of the continuously variable transmission to the input shaft speed as the actual speed ratio. The actual gear ratio is controlled so as to match the target gear ratio according to the operating state. However, since the responsiveness of the gear shift control is low as described above, hunting occurs as shown in FIG. Since the torque of the drive wheels also suddenly changes due to the hunting, the longitudinal acceleration applied to the vehicle body also suddenly changes, and vibration may be applied to the vehicle body to impair drivability and stability.

In engine output control performed by the driving force control device, although the fuel injection cut has a high responsiveness, the control is performed on a cylinder-by-cylinder basis, so that the control resolution is low. Since the variation is large, there is a problem that the variation of the driving force during the driving force control becomes excessive when the engine and the continuously variable transmission are combined.

Therefore, the present invention has been made in view of the above problems, and suppresses the hunting of the gear ratio of the continuously variable transmission when the driving force control device of the vehicle having the continuously variable transmission is operated. In particular, it is an object of the present invention to smoothly suppress idling of drive wheels even when a continuously variable transmission is combined with an engine having a small number of cylinders.

[0007]

A first aspect of the present invention is to provide a drive wheel 50 connected to an engine 4 via a continuously variable transmission 6 and a gear ratio of the continuously variable transmission 6 according to a driving state of a vehicle. , A drive force control start determining means 52 for determining idling of the drive wheel 50 when the slip of the drive wheel 50 on the road surface exceeds a predetermined value, and the drive force control start determining means 52. In the vehicle driving force control device, the driving force control unit 53 includes a driving force suppressing unit 53 that reduces the driving force of the driving wheels 50 when the idling of the driving wheels is determined by the driving force controlling unit 53. Load detection means 5
4. When the engine load is large, the engine output is reduced and the transmission torque of the continuously variable transmission is reduced.
High load idling suppression means 55 for reducing the gear ratio fluctuation amount
When the engine load is small, the engine output
A vehicle drive force control device comprising: a low-load idling suppression unit 56 that inhibits or suppresses a reduction in speed and reduces the transmission torque of the continuously variable transmission 6.

In a second aspect based on the first aspect, the low load idling suppression means increases the response speed of the continuously variable transmission.

In a third aspect based on the first aspect, the high load idling suppression means increases the output reduction gain of the engine.

In a fourth aspect based on the first aspect, the load detecting means detects the load state according to the engine speed when the idling of the drive wheels is detected.

[0011]

In a fifth aspect based on the first aspect, the high load idling suppressing means comprises a fuel injection cutting means.

[0013]

Therefore, according to the first aspect of the invention, when the drive wheels start idling, the high-load idling suppressing means and the low-load idling suppressing means are selectively switched according to the engine load during idling. While the engine output is reduced under high engine load conditions, the idle rotation of the drive wheels is quickly converged, while under low engine load conditions, the transmission torque of the continuously variable transmission is reduced to reduce the idle rotation of the drive wheels. Can be smoothly converged, and for example, in the high load range of the engine where hunting of the continuously variable transmission is likely to occur, the fuel injection cut amount is set large to actively reduce the engine output and By reducing the amount of gear ratio variation of the transmission to prevent hunting, the drive force control device equipped with a continuously variable transmission operates smoothly, and conversely, the output of the engine is reduced due to fuel injection cut. In a low load state in which the driving force fluctuates excessively, the response of the continuously variable transmission can be enhanced to suppress the idling of the drive wheels by continuously shifting the continuously variable transmission to the Hi side. , Regardless of the load state of the engine 4, it becomes possible to always smoothly control the driving force of the vehicle equipped with the continuously variable transmission, and in particular, the output variation of the engine tends to be excessive in the low load region due to the fuel injection cut. It is possible to significantly improve the driving force control performance in the case of combining an engine having a small number of cylinders and a continuously variable transmission as compared with the conventional example.

According to a second aspect of the present invention, the low load idling suppression means increases the response speed of the continuously variable transmission to quickly and smoothly perform the gear shifting to the Hi side according to the idling of the drive wheels. The torque transmitted to the drive wheels can be quickly reduced to suppress idling, and the response speed does not increase during slip in a high load state, so that the gear ratio during drive force control can be prevented.

According to a third aspect of the present invention, the high load idling suppressing means can increase the output reduction gain of the engine to suppress idling of the drive wheels with high responsiveness.
As the output reduction gain, this gain can be increased by increasing the number of fuel injection cut cylinders of the engine.

Further, according to the fourth aspect of the present invention, the load condition of the engine is detected according to the engine speed when the idling of the drive wheels is detected, so that the load condition can be determined easily and quickly without any special calculation. Can be accurately detected.

[0017]

The fifth aspect of the present invention is to reduce the engine output with high responsiveness by performing the high load idling suppression means by fuel injection cut, and by changing the number of fuel injection cut cylinders. The output reduction gain can be easily changed.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, the driving force control device is mainly composed of a TCS controller 1 composed of a microcomputer or the like, and an engine controller for controlling fuel injection cut to the engine 4 in response to a driving force control command signal Fh of the TCS controller 1. 2 and the primary delay constant Kr of the shift control according to the driving force reduction command Fh of the TCS controller 1.
It shows a case where the CVT controller 3 is configured to change the.

The engine 4 connected to the continuously variable transmission 6 is
The fuel injection amount, the ignition timing, etc. are controlled by the engine controller 2 in accordance with the operating state. The engine controller 2 detects the engine speed Ne and the throttle opening sensor 11 during normal operation as in the conventional example. The control is performed according to the throttle opening TVO (or the accelerator pedal depression amount) and the like.

The continuously variable transmission 6 includes rear wheels RR as driving wheels,
The CVT controller 3 is connected to the RL and changes the actual gear ratio (hereinafter, the actual gear ratio) so that the target gear ratio RTO determined by the CVT controller 3 is achieved.
Throttle opening T detected by the throttle opening sensor 11
According to the operating conditions such as VO and the vehicle speed VSP detected by the vehicle speed sensor 5, a target gear ratio RT is calculated from a gear shift map (not shown).
Calculate O.

The continuously variable transmission 6 is of the FR type connected to the rear wheels RR and RL.
RR is a driving wheel and left and right front wheels FL and FR are driven wheels.

The TCS controller 1 includes wheel speed sensors 12FR, 12 for detecting the rotational speed of each wheel or axle.
FL, 12RR, and 12RL detection signals are respectively input, and the TCS controller 1 causes the wheel speeds V _WFR ,
Based on V _WFL , V _WRR , and V _WRL , the idling of the drive wheels RR and RL is detected, and when the drive wheels RR and RL are idling, a drive force control command signal Fh is sent to the engine controller 2 and As in the example, the fuel injection is cut to suppress the output of the engine 4, and the TCS controller 1 also sends the driving force control command signal Fh to the CVT controller 3.

Then, the CVT controller 3 uses this TC
In accordance with the driving force control command signal Fh from the S controller 1, as will be described later, the time constant Kr of the first-order lag for bringing the actual speed ratio closer to the target speed ratio RTO is changed to change the speed of the continuously variable transmission 6. Control the ratio.

The vehicle speed sensor 5 detects the output shaft speed of the continuously variable transmission 6 and multiplies it by a predetermined constant to use as the vehicle speed VSP.

Here, the TCS controller 1 and the CVT
An example of the driving force control and the shift control performed by the controller 3 is shown in the flowchart of FIG. 2, and the driving force control and the shift control will be described in detail below with reference to this flowchart. The control based on this flowchart is executed every predetermined time, for example, every 10 msec.

Steps S1 to S6, S9 and S10 are TC
The control performed by the S controller 1 is shown in step S
8, S11 to S14 represent controls performed by the CVT controller 3 in response to commands from the TCS controller 1.

In step S1, the TCS controller 1
Reads the outputs of the wheel speed sensors 12FR to 12RL to obtain the speeds V _WFR , V _WFL , V _WRR , and V _WRL of the wheels, and reads the rotation speed Ne of the engine 4 from the engine controller 2.

Then, in step S2, the average speed Vwf of the driven wheels is set to the wheel speeds V _WFR , V of the left and right front wheels FR, FL.
_From the average value of _WFL , in step S3, the average speed Vwr of the driving wheels is similarly calculated from the wheel speeds V _WRR and V _WRL of the left and right rear wheels RR and RL.

Next, in step S4, the idling of the drive wheels is detected, and the target value Vws of the drive wheel speed which is the target value of the driving force control is set to a predetermined value of the driven wheel average speed Vwf representing the current vehicle speed. Calculated by adding α.

Vws = Vwf + α Here, the target drive wheel speed Vws is set to, for example, a value obtained by adding a predetermined value α (for example, 2 to 5 km / h) to the driven wheel average speed Vwf.

In step S5, idling of the drive wheels is detected by determining whether the drive wheel average speed Vwr exceeds the target drive wheel speed Vws, and the drive wheel average speed Vwr exceeds the target drive wheel speed Vws. In some cases, it is determined that the drive wheels have idled, and the process proceeds to step S6, while the drive wheel average speed Vwr
Is equal to or lower than the target drive wheel speed Vws, it is determined that the vehicle is normally traveling, and the process proceeds to step S12 and thereafter.

Next, in step S6 in which the idling of the drive wheels is detected, it is determined based on the engine speed Ne whether the current load on the engine 4 is large. That is, when the engine speed Ne is in the high rotation speed region larger than the predetermined value N1, it is determined as a high load state, while when the engine rotation speed Ne is the predetermined rotation speed N1 or less, the low load state. If it is determined that the engine speed Ne is in the low speed region of the predetermined value N1 or less, the process proceeds to step S7, where 0 is set to the driving force control command signal Fh, and then step S8 is performed.
Go to.

In step S8 when the driving force control command signal Fh = 0, the CVT controller 3 uses the read driving force control command signal Fh = 0 to determine the first-order delay time constant Kr used for the shift control as shown in FIG. After setting a value corresponding to the engine speed Ne based on a preset map, the process proceeds to step S9.

On the other hand, if the engine speed Ne exceeds the predetermined value N1 and the engine is in a high load state in step S6, the driving force control command signal Fh is set to 1 in step S10, and then step S11 is performed. move on.

In step S11 where the driving force control command signal Fh = 1, the CVT controller 3 uses the read driving force control command signal Fh = 1 to determine the first-order delay time constant Kr used for the shift control as shown in FIG. After fixing to a predetermined value K1 based on a preset map, step S9
Go to.

The time constant K of the first-order lag shown in FIG.
The map of r is set in advance according to the characteristics of the vehicle, and in the low engine speed region where the engine speed Ne is equal to or lower than the predetermined value N1, the engine speed Ne increases as the engine speed Ne increases from 0 to N1. The constant Kr is a predetermined value K0 to a predetermined value K
The engine speed N is set while gradually increasing to 1.
When e exceeds N1, the time constant Kr is set to be fixed to the predetermined value K1, and these predetermined values are set to the relationship of K0 <K1.

After setting the driving force control command signal Fh and the time constant Kr in accordance with the magnitude of the engine speed Ne in steps S7 and S8 or S10 and S11, the TCS controller 1 operates in step S10. According to the driving force control command signal Fh, the engine controller 2 is requested to reduce the output of the engine 4 according to the slip state of the driving wheels.

That is, the driving force control command signal Fh is 0,
That is, in the low rotation speed region, the maximum value of the fuel injection cut amount is set to Fc1 as shown in FIG. 4, while Fh =
1, that is, the maximum value of the fuel injection cut amount in the high rotation speed region is Fc1 in the low rotation speed region as shown in FIG.
The fuel injection cut amount Fc is variably controlled according to the size of the slip ratio S of the driving wheels, and the output reduction gain of the engine 4 can be changed between the maximum values Fc1 and Fc2. To do.

The slip ratio S is represented by S = Vwr / Vwf, and the TCS controller 1 determines the slip ratio S
Is larger, the fuel injection cut amount Fc is increased, the output of the engine 4 is reduced, and idling of the drive wheels is quickly suppressed.
Subsequent to this driving force control processing, the target gear ratio RTO is calculated in step S13.

If it is determined in step S5 that the vehicle is normally traveling, the process proceeds to step S12, where the driving force control is performed after fixing the primary delay time constant Kr = K1 used for the shift control. No, the process proceeds to step S13.

Next, in step S13, the target gear ratio is set based on the first-order lag time constant Kr set in any of steps S8, S11, and S12, the throttle opening TVO, and the vehicle speed VSP detected by the vehicle speed sensor 5. The actual gear ratio R that is actually output to the continuously variable transmission 6 after calculating the RTO
After calculating the RTO, the continuously variable transmission 6 is instructed in step S12.

That is, in step S12, first, a target gear ratio RTO corresponding to the vehicle speed VSP and the throttle opening TVO is obtained from a preset gear shift map (not shown).

Then, based on the following equation, the actual target speed ratio RRTO of the primary delay is obtained from the primary delay time constant Kr set in S8 or S11, S12, the target speed ratio RTO, and the actual target speed ratio RRTOold in the previous control. Is calculated.

RRTO = (RTO + RRTOold × Kr) / (Kr + 1) (1) Therefore, the target gear ratio RTO and the actual target gear ratio RRTO
The relationship is as shown in FIG. 6, and the engine speed Ne
The actual target speed ratio RRTO gradually changes toward the map value RTO at the speed change speed corresponding to the first-order lag time constant Kr set in accordance with the above. Although FIG. 6 shows the case where the shift is performed from the Hi side to the Lo side, the actual target gear ratio RRTO gradually changes in the opposite case as well.

When the driving wheel RR or RL starts idling and the driving wheel speed Vwr becomes a slip state in which the driving wheel speed Vwr exceeds the threshold value Vws by performing the processing of steps S1 to S14 at predetermined time intervals, the TCS controller 1 Detects the load state of the engine 4 from the engine speed Ne, and in the high speed region (high load region) where the engine speed Ne exceeds the predetermined value N1, as shown in FIG. The time constant Kr of is fixed to the time constant K1 similar to that during normal traveling, and is set so that the actual gear ratio gradually changes with the passage of time t, while the driving force control is performed by the fuel injection cut amount Fc. The maximum value of Fc2 is set to the maximum value, and fuel injection is actively cut to suppress idling of the drive wheels.

On the other hand, in the low rotation speed region (low load region) in which the engine rotation speed Ne is equal to or lower than the predetermined value N1, as shown in FIG. Since the value is set to a small value equal to or less than the time constant K1, the speed change speed of the continuously variable transmission 6 is set higher than in the slip state during normal traveling or at the time of the high load, and the actual speed ratio accompanying the idling of the drive wheels Of the fuel injection cut amount Fc, the maximum value of the fuel injection cut amount Fc is smaller than Fc2 at the time of high load.
1, the suppression of engine output due to fuel injection cut is reduced.

That is, when the load is low, as shown in FIG. 4, when the drive wheels run idle at time t0 and a slip state is detected, the maximum value of the fuel injection cut amount Fc is higher than that at the time of high load. While the reduction of the engine output is suppressed by setting to a small Fc1, the time constant Kr of the first-order lag is set to a small value of K1 or less according to the engine speed Ne, so that there is no decrease according to the decrease of the time constant Kr. Since the shift speed of the stepped transmission 6 is high and the vehicle speed VSP detected by the idling of the drive wheels RR and RL is high, the target speed ratio RTO changes from the map of FIG. 7 to the Hi side, and toward this Hi side. The transmission torque to the drive wheels can be reduced by performing the gear shift quickly, and the idling of the drive wheels can be gently suppressed. By suppressing the fuel injection cut amount Fc, the output fluctuation of the engine 4 is suppressed. Nothing It is possible to suppress the idle rotation of the driving wheels by a continuous transmission ratio control of the transmission 6.

On the other hand, in the high load, as shown in FIG. 5,
When the slip state is detected even if the drive wheels idle at time t0, the maximum value of the fuel injection cut amount Fc is set to Fc2 which is larger than that at the time of the low load, and the engine output is actively reduced. As a result, the idle speed of the drive wheels is suppressed, and the first-order lag time constant Kr is fixed to K1 as during normal traveling. Therefore, the speed change speed (sensitivity) of the continuously variable transmission 6 becomes small, which is different from the conventional example. Hunting can be prevented.

Thus, in the high load region of the engine 4 where hunting of the continuously variable transmission 6 is likely to occur, the fuel injection cut amount is set to a large amount to actively reduce the output of the engine 4, and at the same time, the continuously variable transmission 6 is also reduced. By reducing the amount of change in the gear ratio and preventing hunting, the drive force control device equipped with the continuously variable transmission 6 operates smoothly, and conversely, the output reduction of the engine 4 due to the fuel injection cut reduces the drive force. In the low load region where the fluctuation of the variable speed of the continuously variable transmission 6 becomes large, the speed change speed is increased by setting the time constant Kr of the first-order lag of the continuously variable transmission 6 to be small.
It is possible to suppress the idling of the drive wheels by continuously shifting to the Hi side, and regardless of the load state of the engine 4,
It becomes possible to smoothly and smoothly control the driving force of the vehicle equipped with the continuously variable transmission 6, and particularly, the output variation of the engine 4 in the low load region is likely to be excessive due to the fuel injection cut. The driving force control performance in the case of combining the continuously variable transmission 6 can be significantly improved as compared with the conventional example.

FIG. 8 shows a second embodiment, in which the driving force control process performed in step S9 of the first embodiment is performed only when the engine 4 is under a heavy load, and other configurations are the same as those of the first embodiment. This is similar to that of the first embodiment.

In this case, the slip of the drive wheels is detected, and the engine speed Ne is determined in step S6, the process proceeds to step S9 only when the engine is in a high load state, and the engine output is quickly reduced by cutting the fuel injection. Therefore, the idle rotation of the drive wheels can be promptly converged.

On the other hand, at the time of slip in the low load state, reduction of the engine output due to fuel injection cut is prohibited, while the time constant Kr of the continuously variable transmission 6 is set to a small value to the Hi side of the continuously variable transmission 6. The transmission torque to the drive wheels can be reduced only by a quick shift of the drive wheels, and the idling of the drive wheels can be smoothly converged. By switching the means for suppressing the slip according to the load state of the engine 4, ,
When the engine 4 having a small number of cylinders and the continuously variable transmission 6 are combined, the fuel injection cut under the low load condition is prohibited to smoothly operate the driving force control device regardless of the load condition. It is possible to improve drivability and stability.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a driving force control device showing an embodiment of the present invention.

FIG. 2 is a flowchart showing an example of control similarly performed by the TCS controller and the CVT controller.

[FIG. 3] Similarly, first-order lag time constant Kr and engine speed N
It is a map which shows the relationship of e.

FIG. 4 is a graph showing a state of driving force suppression control when a drive wheel spins in a low load state, and is a graph showing a relationship between each wheel speed, a gear ratio, and a fuel injection cut amount Fc.

FIG. 5 is a graph showing a state of driving force suppression control when a drive wheel spins in a high load state, and is a graph showing a relationship between each wheel speed, a gear ratio, and a fuel injection cut amount Fc.

FIG. 6 is an actual target gear ratio RRT according to a first-order delay constant Kr.
It is a graph which shows a mode of change of O.

FIG. 7 is a map of a target input shaft rotation speed tNt according to a vehicle speed VSP with a throttle opening TVO as a parameter.

FIG. 8 is a flowchart showing the second embodiment and showing an example of control performed by a TCS controller and a CVT controller.

FIG. 9 shows a conventional example, shows a state of gear ratio hunting in an acceleration slip state, and shows a relationship between a vehicle speed VSP and a throttle opening TVO.

FIG. 10 is a claim correspondence diagram corresponding to the first to sixth inventions.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 TCS controller 2 Engine controller 3 CVT controller 4 Engine 5 Vehicle speed sensor 6 Continuously variable transmission 11 Throttle opening sensor 12FR, 12FL, 12RR, 12RL Wheel speed sensor 51 Shift control means 52 Driving force control start determination means 53 Driving force suppressing means 54 load detection means 55 high load idling suppression means 56 low load idling suppression means

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F02D 29/02 311 F02D 29/02 311A F16H 61/00 F16H 61/00 // F16H 59:42 59:42 63:06 63: 06 (56) Reference JP-A 63-270950 (JP, A) JP-A 2-144233 (JP, A) JP-A 1-136834 (JP, A) JP-A 3-99945 (JP, A) JP-A-7-166907 (JP, A) JP-A-5-86918 (JP, A) JP-A-5-296071 (JP, A) JP-A-3-202646 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60K 28/16 B60K 41/12 F02D 29/00 F02D 29/02 311 F16H 61/00

Claims (5)

(57) [Claims] 1. A drive wheel connected to an engine through a continuously variable transmission, a shift control means for setting a gear ratio of the continuously variable transmission according to a driving state of a vehicle, and a drive wheel with respect to a road surface. A drive force control start determination means for determining idling of the drive wheels when the slip exceeds a predetermined value, and a drive for reducing the drive force of the drive wheels when the drive force control start determination means determines the idling of the drive wheels In a vehicle driving force control device including force suppressing means, the driving force controlling means detects load of an engine, and when the engine load is large, reduces the engine output and continuously Shifting to reduce transmission torque of transmission
High load idling suppression means to reduce the amount of ratio fluctuation , and engine output reduction when the engine load is small.
A drive force control device for a vehicle, comprising: a low load idling suppression means for inhibiting or suppressing , and reducing a transmission torque of a continuously variable transmission. 2. The vehicle drive force control device according to claim 1, wherein the low load idling means increases the response speed of the continuously variable transmission. Wherein said high-load idling suppression means according to claim 1, characterized in that to increase the output reduction gain of the engine or
Or the driving force control device for a vehicle according to item 2 . 4. The load detecting means detects the load state according to the engine speed when the idling of the drive wheels is detected, according to any one of claims 1 to 3 . Vehicle driving force control device. Wherein said high-load idling control means, claim 1, characterized in that with a fuel injection cut means 4 Neu
The driving force control device for a vehicle according to claim 1.