JP2000346191A - Driving force control device for vehicle deceleration - Google Patents

Abstract

(57) [Problem] To control an engine coast torque when a target speed ratio calculated from a target deceleration is equal to or lower than a predetermined speed ratio corresponding to a minimum input rotation speed. SOLUTION: At the time of deceleration, a target deceleration is calculated from a vehicle speed (S1, S2), a target speed ratio is calculated so as to be the target deceleration (S3, S4), and a continuously variable transmission is set so as to be the target speed ratio. Is controlled (S6). If the target speed ratio is equal to or less than the predetermined speed ratio, the target speed ratio is fixed at the predetermined speed ratio (S5, S7). Then, a decrease in engine coast torque for achieving the target deceleration at the predetermined gear ratio is calculated (S8). If the torque decrease is equal to or less than the predetermined value, the opening of the electronically controlled throttle valve is controlled so as to obtain this value (S
9, S10, S12). If the torque decrease is larger than the predetermined value, the fuel recovery of some cylinders is performed (S11, S11).
12).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deceleration driving force control device for a vehicle having a continuously variable transmission.

[0002]

2. Description of the Related Art A conventional deceleration driving force control apparatus for a vehicle equipped with a continuously variable transmission is designed to achieve a target deceleration at the time of deceleration of the vehicle as shown in the following (1) and (2). In some cases, the speed ratio of a continuously variable transmission is variably controlled.

(1) Japanese Patent Application Laid-Open No. 3-103655 Purpose: When traveling with the accelerator fully closed, the engine brake is effectively activated according to the vehicle speed at that time.

Configuration: Detects accelerator fully closed, vehicle speed v, and vehicle deceleration A (G sensor output or Δv).
Then, the target deceleration A0 during traveling with the accelerator fully closed is determined according to the vehicle speed v, and the speed ratio of the continuously variable transmission is variably controlled so that the actual deceleration A becomes the target deceleration A0. . Specifically, a deceleration difference ΔA = A−A0 is obtained,
From the deceleration difference ΔA, a correction value C of the target primary rotational speed is obtained.
Is calculated and corrected.

Thus, the higher the vehicle speed (the target deceleration A
Set 0 to a large value) to make the engine brake more effective and obtain a large deceleration. (2) Japanese Patent Application Laid-Open No. Hei 9-112680 Object: To control an engine brake during coasting so as to obtain a sense of deceleration according to a driver's expectation according to a vehicle speed. That is, the deceleration caused by the engine brake during the inertial running with the accelerator pedal released is changed according to the vehicle speed, and the feeling of deceleration expected by the driver is obtained.

In accordance with the present invention, a target input rotation speed of an input shaft of a continuously variable transmission is calculated in accordance with a driving state of a vehicle, and the speed of the continuously variable transmission is changed so that the input shaft rotation speed matches the target input rotation speed. A shift control device for controlling a ratio detects an acceleration of a vehicle and an operation state of an accelerator pedal.

When the release of the accelerator pedal is detected, the detected acceleration is compared with a predetermined threshold value.
When the acceleration exceeds the threshold value, the target input speed is corrected so as to increase (this correction amount is added to the target input speed). The threshold value is decreased as the vehicle speed increases.

Then, gear ratio control is performed based on the corrected target input rotational speed.

[0009]

However, as described above, when the speed ratio of the continuously variable transmission is variably controlled so that the target deceleration is achieved when the vehicle is decelerated, the following problems arise. there were.

That is, when the control of the deceleration is only the gear ratio, the minimum input rotation speed determined by the continuously variable transmission (necessary for obtaining a hydraulic pressure capable of controlling the gear ratio by an oil pump driven by the engine). Due to restrictions on the engine speed, it is difficult to control the speed ratio (= input speed / output speed) below a predetermined speed ratio, and the control range is limited. When trying to expand the region to the low vehicle speed side, the deceleration exceeds the control region (large deceleration), and there is a problem that a feeling of driving discomfort occurs.

In view of such a conventional problem, the present invention provides a throttle opening in addition to the conventional speed ratio when the target speed ratio calculated from the target deceleration is equal to or lower than a predetermined speed ratio corresponding to the minimum input speed. It is an object of the present invention to control the engine coast torque based on the degree (and partial cylinder fuel recovery) to achieve both improved fuel economy and a sense of deceleration.

[0012]

Therefore, in the invention according to the first aspect, as shown in FIG. 1, at the time of deceleration, the target deceleration calculating means calculates the target deceleration from the vehicle speed to calculate the target gear ratio. The target gear ratio is calculated by the means so as to achieve the target deceleration, and the gear ratio of the continuously variable transmission is controlled by the gear ratio control means to achieve the target gear ratio.

On the other hand, when the target speed ratio by the target speed ratio calculating means is equal to or less than a predetermined speed ratio, the target speed ratio of the speed ratio control means is limited to the predetermined speed ratio by the target speed ratio limiting means. Then, the engine coast torque reduction calculating means calculates the engine coast torque reduction for achieving the target deceleration at the predetermined gear ratio, and the throttle opening control means obtains the engine coast torque reduction. Thus, the opening of the electronically controlled throttle valve in the engine during fuel cut is controlled.

[0014] In the invention according to claim 2, the fuel recovery control means for the partial cylinders of the cylinders during fuel cut-off so as to obtain the decrease in the engine coast torque under a predetermined condition by the partial cylinder fuel recovery control means. I do.

According to a third aspect of the present invention, the partial cylinder fuel recovery control means changes the number of fuel recovery cylinders in accordance with the decrease in the engine coast torque.

The invention according to claim 4 is characterized in that the partial cylinder fuel recovery control means is activated when the engine torque reduction is greater than a predetermined value. The invention according to claim 5 is characterized in that the operation of the throttle opening control means is stopped when the partial cylinder fuel recovery control means operates.

In the invention according to claim 6, the target speed ratio calculating means calculates the target speed ratio based on the target deceleration and a reference engine coast torque corresponding to a current engine speed. Features.

In the invention according to claim 7, the engine coast torque decrease calculating means calculates the engine coast torque at the predetermined speed ratio at the target deceleration from a reference engine coast torque corresponding to the current engine speed. It is characterized in that the engine coast torque reduction is calculated by subtraction.

[0019]

According to the first aspect of the present invention, when the target speed ratio calculated from the target deceleration is equal to or less than the predetermined speed ratio during deceleration, the target speed ratio is fixed to the predetermined speed ratio. Calculate the amount of decrease in engine coast torque to achieve the target deceleration at the predetermined gear ratio, and control the opening of the electronically controlled throttle valve in the engine during fuel cut so as to obtain this, that is, open the throttle valve. By reducing the pump loss, the engine coast torque is reduced, and the fuel cut-off area at the time of deceleration is expanded to improve fuel efficiency.
It is possible to realize the feeling of discomfort during deceleration.

According to the second aspect of the present invention, it is possible to greatly reduce the engine coast torque by performing partial cylinder fuel recovery so as to obtain the engine coast torque decrease under predetermined conditions. The control area can be greatly expanded.

According to the third aspect of the present invention, fine control can be performed by changing the number of fuel recovery cylinders in accordance with the decrease in engine coast torque in the partial cylinder fuel recovery control.

According to the present invention, when the decrease in the engine coast torque is equal to or less than the predetermined value, the throttle opening degree control is performed, and the fine control is performed while improving the fuel efficiency, thereby reducing the engine coast torque. When the value becomes larger, the partial cylinder fuel recovery control is performed, and the control region can be expanded.

According to the fifth aspect of the present invention, at the time of the partial cylinder fuel recovery control, by fully closing the throttle opening, it is possible to secure the suction negative pressure and prevent the operability from deteriorating.

According to the invention of claim 6, when calculating the target speed ratio, the target speed ratio can be accurately calculated by using the reference engine coast torque at the current engine speed.

According to the present invention, the torque at the predetermined speed ratio at the target deceleration is subtracted from the reference engine coast torque at the current engine speed to obtain the decrease in engine coast torque. , Can be accurately calculated.

[0026]

Embodiments of the present invention will be described below. FIG. 2 is a system diagram of one embodiment of the present invention.

Electronically controlled throttle valve 2 for intake system of engine 1
Is connected to a step motor (or servo motor) 3 as a throttle actuator, and this motor 3 is driven by a signal from the control unit 10.

The fuel injection valve 4 is provided for each cylinder of the engine 1 and is similarly driven by a signal from the control unit 10. The control unit 10 includes a crank angle sensor 11 that can detect an engine speed Ne, an air flow meter 12 that detects an intake air amount Qa, a negative pressure sensor 13 that detects a suction negative pressure Pb, an accelerator opening (depression of an accelerator pedal). Amount) accelerator opening sensor 14 for detecting APO, throttle opening (opening of throttle valve 2) T
Throttle opening sensor 15 for detecting VO, vehicle speed VSP
A signal is input from a vehicle speed sensor 16 or the like that detects the vehicle speed.

Here, the control unit 10
Sets a target throttle opening based on the accelerator opening APO mainly by a built-in microcomputer, and sets the target throttle opening through the motor 3 so as to reach the target throttle opening.
The opening of the electronically controlled throttle valve 2 is controlled.

The control unit 10 also calculates a fuel injection amount corresponding to a target air-fuel ratio based on the intake air amount Qa (or suction negative pressure Pb) and the engine speed Ne, and the fuel injection valve 4 of each cylinder is calculated. In response to this, at a predetermined timing synchronized with the engine rotation, an injection pulse signal having a pulse width corresponding to the fuel injection amount is output to perform the fuel injection.
On the other hand, at the time of deceleration, a fuel cut for stopping fuel injection by the fuel injection valve 4 is performed until the engine speed Ne decreases to a predetermined recovery speed.

A continuously variable transmission (CVT) 6 is connected to the output side of the engine 1 via a torque converter 5 with a lock-up mechanism as an automatic transmission. FIG. 3 is a system diagram on the automatic transmission side.

The continuously variable transmission (CVT) 6 includes a primary pulley 22 having an input shaft 21 connected to an output shaft of an engine via a torque converter 5 having a lock-up mechanism and having a continuously variable effective diameter. A secondary pulley 24 whose effective diameter on the output shaft 23 side (differential side) can be continuously changed;
A belt 25 wound between these pulleys 22 and 24
, The primary side cylinder 26 that receives the primary pressure (shift pressure) and acts on the primary pulley 22 in the radially increasing direction, and the secondary pulley 24 that receives the line pressure and
And a secondary side cylinder 27 acting in the radially expanding direction.

Here, the line pressure input to the secondary side cylinder 27 is generated by a line pressure control valve 28 having a relief function using a hydraulic pressure from an oil pump (not shown) driven by the engine as a source pressure.

The primary pressure input to the primary side cylinder 26 is generated by a shift control valve 29 having a relief function using the line pressure as the original pressure. Therefore, the primary pressure is always lower than the line pressure, but the pressure receiving area of the primary side cylinder 26 is
Since the pressure receiving area is set larger than the pressure receiving area 7, by controlling the ratio of the primary pressure to the line pressure (primary pressure / line pressure), the pulley ratio can be changed and the speed ratio can be changed steplessly. .

Line pressure control valve 28 and shift control valve 29
Is duty-controlled by the control unit 10. Here, the control unit 10
Controls the line pressure control valve 28 and the speed change control valve 29 by a built-in microcomputer based on various input signals to control the line pressure and the primary pressure (speed ratio).

That is, based on the throttle opening TVO (or the accelerator opening APO), the target line pressure is calculated by referring to a predetermined table. Then, the line pressure is controlled by performing duty control on the line pressure control valve 28 so as to obtain the target line pressure. Further, based on the accelerator opening APO and the vehicle speed VSP, a target speed ratio is calculated with reference to a speed change map. Then, the duty ratio of the shift control valve 29 is controlled so as to obtain the target speed ratio to control the ratio of the primary pressure to the line pressure, thereby controlling the speed ratio.

The control unit 10 is usually
The control unit for controlling the engine and the control unit for controlling the transmission are separated, and necessary information is exchanged through a communication line. However, they are shown integrally here for simplification of description.

Next, the deceleration driving force control according to the present invention performed by the control unit 10 will be described with reference to a flowchart. FIG. 4 is a flowchart of a deceleration-time driving force control routine, which is executed at predetermined time intervals.

In step 1 (referred to as S1 in the figure, the same applies hereinafter), the accelerator opening A is used to determine whether or not the vehicle is decelerating.
It is determined whether or not PO = 0 (fully closed). If the PO is fully closed, the process proceeds to step 2 for the drive force control during deceleration.

In step 2, the target deceleration (ΔVSP) is calculated from the vehicle speed VSP by referring to the table shown in FIG. In step 3, a reference engine coast torque during throttle valve fully closed and fuel cut is calculated with reference to the table in FIG. 6 from the engine speed Ne.

In step 4, a target gear ratio is calculated from the target deceleration and the reference engine coast torque using the following equation. (Target gear ratio) = [(Target deceleration) × W × r] / [if
× (reference engine coast torque)] Here, W is the vehicle weight, r is the tire diameter, and if is the F / D gear ratio.

In step 5, the calculated target gear ratio is compared with a predetermined gear ratio corresponding to the minimum input speed to determine whether the target gear ratio is equal to or less than the predetermined gear ratio. If the target speed ratio exceeds the predetermined speed ratio, the process directly proceeds to step 6, and
The gear ratio control is performed so as to achieve the target gear ratio calculated in step 4, and this routine ends. Of course, at this time, the full cylinder fuel cut is performed with the throttle valve fully closed.

If the target speed ratio is equal to or less than the predetermined speed ratio, the process proceeds to step 7 and subsequent steps. In step 7, the target gear ratio is fixed at a predetermined gear ratio. In step 8, the decrease in engine coast torque is calculated by the following equation.

(Engine coast torque decrease) = (reference engine coast torque) − [(target deceleration) × W ×
r] / [if × (predetermined gear ratio)] Here, W is the vehicle weight, r is the tire diameter, and if is the F / D gear ratio.

That is, the engine coast torque at a predetermined speed ratio at the target deceleration is subtracted from the reference engine coast torque corresponding to the current engine speed to calculate the engine coast torque reduction.

In step 9, it is determined whether the calculated decrease in engine coast torque is equal to or less than a predetermined value achievable by throttle opening control. When the decrease in engine coast torque is equal to or less than the predetermined value, the process proceeds to step S10.

In step 10, a target throttle opening for deceleration-time driving force control is calculated from the decrease in engine coast torque with reference to the table of FIG. If the decrease in engine coast torque is larger than the predetermined value, the process proceeds to step S11.

In step 11, the number of fuel recovery cylinders for controlling the deceleration driving force is calculated from the decrease in the engine coast torque with reference to the table shown in FIG. Step 1
After 0 or step 11, the process proceeds to step 12.

In step 12, the gear ratio control is performed, the throttle opening control or the partial cylinder fuel recovery control is performed, and the routine is terminated. That is, while the gear ratio is controlled so as to be the target gear ratio fixed at step 7 (= predetermined gear ratio), if the decrease in engine coast torque is equal to or less than the predetermined value, the fuel cut state is maintained, and The electronically controlled throttle valve is controlled so as to achieve the target throttle opening set in step 10. If the decrease in engine coast torque is larger than the predetermined value, the throttle valve is fully closed and fuel recovery is performed for the number of fuel recovery cylinders set in step 11.

As described above, at the time of deceleration, when the target speed ratio calculated from the target deceleration is equal to or less than the predetermined speed ratio, the target speed ratio is fixed at the predetermined speed ratio, while the target speed reduction is performed at the predetermined speed ratio. By calculating the amount of decrease in engine coast torque to achieve the speed and controlling the opening of the electronically controlled throttle valve in the engine during fuel cut to obtain this, that is, by opening the throttle valve and reducing pump loss,
Decrease engine coast torque. If the decrease in engine coast torque is large, a further request is answered by partial cylinder fuel recovery.

Step 2 corresponds to the target deceleration calculating means, steps 3 and 4 correspond to the target speed ratio calculating means, and steps 6 and 12 correspond to the speed ratio controlling means. . Steps 5 and 7 correspond to target speed ratio limiting means, and step 8 corresponds to engine coast torque reduction calculating means.
Portions 0 and 12 correspond to throttle opening control means, and steps 9, 11, and 12 correspond to partial cylinder fuel recovery control means.

In this embodiment, the switching between the throttle opening control and the partial cylinder fuel recovery control is performed in step 10 by comparing the decrease in engine coast torque with a predetermined value. , The suction negative pressure may be detected, and the suction negative pressure may be compared with a predetermined value to switch between throttle opening control and partial cylinder fuel recovery control. That is, when the intake negative pressure falls below a predetermined value by the throttle opening control, the control is switched to the partial cylinder fuel recovery control. In this case, the predetermined value for determining the suction negative pressure may be a negative pressure determined from restrictions such as a brake negative pressure.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of the present invention.

FIG. 2 is a system diagram showing an embodiment of the present invention.

FIG. 3 is a system diagram of an automatic transmission.

FIG. 4 is a flowchart of a deceleration-time driving force control routine.

FIG. 5 is a diagram showing a target deceleration calculation table.

FIG. 6 is a diagram showing a reference engine coast torque calculation table;

FIG. 7 is a diagram showing a target throttle opening calculation table;

FIG. 8 is a diagram showing a fuel recovery cylinder number calculation table;

[Explanation of symbols]

 Reference Signs List 1 engine 2 electrically controlled throttle valve 3 motor 4 fuel injection valve 5 torque converter with lock-up mechanism 6 continuously variable transmission 10 control unit 11 crank angle sensor 12 air flow meter 13 negative pressure sensor 14 accelerator opening sensor 15 throttle opening sensor 16 Vehicle speed sensor 21 Input shaft 22 Primary pulley 23 Output shaft 24 Secondary pulley 25 Belt 26 Primary cylinder 27 Secondary cylinder 28 Line pressure control valve 29 Shift control valve

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16H 63:06 F term (Reference) 3G093 AA06 BA19 CB07 DA03 DA06 DB05 DB11 DB21 EA05 EA08 EA09 EB03 EC02 FA08 FA11 FB02 FB05 3G301 HA01 JA02 KA16 KA26 LA03 LB02 LC03 MA25 NA08 NE19 PA07Z PA11A PA11Z PE01Z PE06Z PF02Z PF08Z 3J052 AA04 AA14 BB02 CA21 EA04 FB34 GC03 GC13 GC23 GC36 GC44 GC46 GC72

Claims (7)

[Claims] An engine having an electronically controlled throttle valve and a continuously variable transmission, a target deceleration calculating means for calculating a target deceleration from a vehicle speed at the time of deceleration, and a target speed change ratio for achieving the target deceleration. A deceleration driving force control device for a vehicle, comprising: a target gear ratio calculating means for calculating; and a gear ratio control means for controlling a gear ratio of the continuously variable transmission to achieve the target gear ratio. And a target speed ratio limiting means for limiting a target speed ratio of the speed ratio control means to the predetermined speed ratio when the target speed ratio is equal to or less than a predetermined speed ratio, and achieving the target deceleration at the predetermined speed ratio. Coast torque reduction calculating means for calculating the engine coast torque reduction for the engine, and an electronically controlled throttle in the engine during fuel cut so as to obtain the engine coast torque reduction. The deceleration driving force control apparatus for a vehicle, characterized in that the throttle opening control means, the provided for controlling the opening. 2. A partial cylinder fuel recovery control means for performing fuel recovery of a part of the cylinders during fuel cut so as to obtain the engine coast torque reduction under a predetermined condition. Item 2. The deceleration-time driving force control device for a vehicle according to Item 1. 3. The deceleration driving force control device for a vehicle according to claim 2, wherein the partial cylinder fuel recovery control means changes the number of fuel recovery cylinders in accordance with the decrease in the engine coast torque. 4. The partial cylinder fuel recovery control means is activated when the engine coast torque reduction is greater than a predetermined value.
7. The deceleration-time driving force control device for a vehicle according to claim 1. 5. The vehicle according to claim 2, wherein the operation of the throttle opening control means is stopped when the partial cylinder fuel recovery control means is operated. Driving force control device during deceleration. 6. The target speed ratio calculating means calculates a target speed ratio based on the target deceleration and a reference engine coast torque corresponding to a current engine speed. The deceleration-time driving force control device for a vehicle according to any one of claims 1 to 5. 7. The engine coast torque reduction calculating means subtracts an engine coast torque at the predetermined speed ratio at the target deceleration from a reference engine coast torque corresponding to a current engine speed, thereby obtaining an engine coast torque. The deceleration-time driving force control device for a vehicle according to any one of claims 1 to 6, wherein a torque reduction is calculated.