JP2001150981A - Control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fuel consumption by using a control device for a vehicle for properly detecting the gentle acceleration and enriched-zone acceleration of the vehicle and setting a target output out of an enriched zone. SOLUTION: The gentle acceleration and enriched-zone acceleration of the vehicle are detected in accordance with an accelerator opening APS and a target air/fuel ratio KAF, and a target Pe1 of an engine 11 and a target Np1 of a CVT 16 are set corresponding to the conditions of the gentle acceleration and enriched-zone acceleration and changed to a target Pe2 of the engine 11 and a target Np2 of the CVT 16 to obtain a target horse power PS near a stoichiometric air/fuel ratio. A Pe correcting coefficient Kpe is found in accordance with a deviation ΔNp between a actual rotating speed Npr and a target Np2 of a primary shaft 17 of the CTV 16 for correcting the target Np2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a control device for a vehicle having an internal combustion engine and a continuously variable transmission.

[0002]

2. Description of the Related Art C used as a belt-type continuously variable transmission
VT (Continuously Variable Transmission) generally has a belt wound around a primary pulley connected to an input shaft and a secondary pulley connected to an output shaft.
By supplying / discharging hydraulic pressure to / from the cylinder of each pulley, each groove width of the primary pulley and the secondary pulley is relatively changed to change the speed.

Conventionally, in such a CVT, a controller sets a required output required by the vehicle based on an accelerator opening operated by a driver and a speed (vehicle speed) of the vehicle, and the required output is exhibited. The speed ratio of the CVT is set so as to be set. Then, the controller controls the hydraulic pressure so as to achieve the set speed ratio, thereby relatively changing the groove widths of the primary pulley and the secondary pulley, and causing the vehicle to travel as required by the driver.

[0004]

By the way, in a vehicle having an engine equipped with a CVT, when a driver depresses an accelerator pedal to accelerate, the controller outputs a required output set based on the accelerator opening and the vehicle speed. The speed ratio of the CVT is increased so as to be exerted, that is, set to the deceleration side.

[0005] In such a CVT shift control, for example, the driver intends to accelerate slowly, but suddenly presses the accelerator pedal too much and feels more acceleration than expected. You may notice that the accelerator pedal is released. In this case, in order to obtain high horsepower corresponding to the large accelerator opening, the engine enters the low-speed, high-load enriched operation area once, and then returns to the desired horsepower operation area by returning the accelerator pedal. Here, there is a problem that fuel efficiency is deteriorated.

[0006] Such a phenomenon will be described in detail. FIG. 5 is a graph showing an operation state of a vehicle having an engine and a CVT by a conventional control device. As shown in FIG. 5, when the driver suddenly depresses the accelerator pedal from the low-speed low-load acceleration start position of the engine, the operating state of the engine is determined based on the accelerator opening and the vehicle speed, based on the target average effective pressure, That is, the engine load (output) Pe is set, and the engine shifts to the high acceleration initial position on the horsepower A curve. Then, as the engine speed Ne rises, the gear ratio is reduced to shift to a middle acceleration position on the horsepower B curve, and the horsepower B
Move on the curve to the end of acceleration position. Thereafter, when the driver returns the accelerator pedal, the engine speed Ne and the engine load Pe decrease, and the driver moves to a desired acceleration position on a desired horsepower A curve. When the operating state of the engine changes, the vehicle speed is substantially constant, and the engine speed Ne and the engine load Pe increase, and the vehicle enters the enrichment zone during acceleration, leading to deterioration of fuel efficiency.

[0007] Japanese Patent Publication No. 3-35536 discloses, for example, Japanese Patent Publication No. Hei 3-35536, which is capable of sufficiently obtaining acceleration in a transient state after an acceleration operation. Is effective, but there is a problem that sufficient output cannot be obtained at the time of slow acceleration, and further, a feeling of acceleration cannot be obtained due to the inertia torque of the CVT.

The present invention has been made to solve the above-described problem, and aims to improve fuel efficiency and prevent poor acceleration by properly detecting slow acceleration of a vehicle and setting a target output that does not cause an enrichment zone. To provide a vehicle control device with improved drivability.

[0009]

In order to achieve the above-mentioned object, the vehicle control apparatus according to the first aspect of the present invention detects slow acceleration of the vehicle, and the target air-fuel ratio at this time is higher than the stoichiometric air-fuel ratio. Calculate the target horsepower according to the driving state when
A target output and a target rotational speed for obtaining the target horsepower in the vicinity of the stoichiometric air-fuel ratio are set, and the speed ratio of the continuously variable transmission and the output of the internal combustion engine are controlled so as to achieve the set target output and the target rotational speed. Like that.

Therefore, when the vehicle is slowly accelerated and the enriched air-fuel ratio is detected, the target output and the target rotational speed for obtaining the target horsepower near the stoichiometric air-fuel ratio are set, so that the operation state of the internal combustion engine is changed to the enriched zone. , And deterioration of fuel efficiency due to inadvertent acceleration of the driver due to excessive depression of the accelerator pedal is prevented.

In the vehicle control apparatus according to the present invention, the actual rotation speed of the input shaft of the continuously variable transmission is detected, and the target output is corrected based on the target rotation speed and the actual rotation speed. The output of the internal combustion engine is controlled based on the corrected target output. Therefore, since the output of the internal combustion engine is controlled using the actual rotational speed of the input shaft of the continuously variable transmission, poor acceleration can be prevented and drivability can be improved.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic configuration of a vehicle control device according to one embodiment of the present invention, FIG. 2 is a flowchart of CVT output control by the vehicle control device of this embodiment, and FIG. FIG. 4 is a graph showing a rotational speed and an engine load, and FIG. 4 is a graph showing a correction coefficient for a primary rotational speed deviation.

In the vehicle control apparatus according to the present embodiment, as shown in FIG. 1, a drive shaft 12 of an engine 11 is connected to a torque converter 13, and an output shaft 14 of the torque converter 13 is connected via a transmission clutch 15. An input shaft (primary shaft) 17 of a CVT 16 as a step transmission can be connected and disconnected, and the transmission clutch 15 can be driven by an actuator 18 operated by a hydraulic drive device (not shown). This CVT 16 is the engine 11
Pulley 19 connected to the side of the vehicle, a secondary pulley 20 connected to the noise shaft side of the vehicle, and both pulleys 19 and 2.
The rotation input to the primary shaft 17 is input from the coaxially integrated primary pulley 19 to the secondary pulley 20 via the belt 21 and output to the secondary shaft 22. It has become so.

That is, the primary pulley 19 has a fixed sheave 19a and a movable sheave 19b.
A primary cylinder 19c is formed on the back side of the main body. Therefore, by supplying / discharging the hydraulic pressure to / from the primary cylinder 19c, the movable sheave 19
By moving b, the groove width of the pulley can be made variable.
On the other hand, similarly, the secondary pulley 20 is
a and a movable sheave 20b, and a secondary cylinder 20c is formed on the back side of the movable sheave 20b. Therefore, by supplying and discharging hydraulic pressure to and from the secondary cylinder 20c, the movable sheave 20b can be moved relative to the fixed sheave 20a, and the groove width of the pulley can be made variable.

The CVT 16 is controlled by a hydraulic circuit. That is, the secondary hydraulic pressure (line pressure) adjusted by the regulator valve 23 is applied to the secondary cylinder 20c, and the primary oil pressure adjusted by the speed ratio control valve 24 to the line pressure is applied to the primary cylinder 19c. Note that 25
Reference numeral denotes an oil pan, and reference numeral 26 denotes an oil pump that supplies oil in the oil pan 25 to the regulator valve 23 side.

The secondary shaft 22 of the CVT 16 is connected to a differential gear 28 via a starting clutch 27. The starting clutch 27 can be driven by an actuator 29 operated by a hydraulic drive device (not shown). The amount of torque transmitted from the shaft 22 to the left and right drive wheels 30 can be adjusted.

The vehicle includes an engine 11 and a CVT 16.
Electronic control unit (ECU) for engine that controls
The ECU 31 includes an input / output device, a storage device that stores a control program, a control map, and the like, a central processing unit, and a timer and a counter.
The ECU 31 performs comprehensive control of the engine 11. That is, detection information of various sensors such as an engine speed sensor (crank angle sensor) 32, a vehicle speed sensor 33, an accelerator pedal position sensor 34, and a primary speed sensor 35 is input to the ECU 31.
31 determines a fuel injection mode, a fuel injection amount, an ignition timing, and the like based on detection information of various sensors. Furthermore, EC
The U31 can change the pulley ratio by controlling the hydraulic pressure of the regulator valve 23 and the gear ratio control valve 24 of the CVT 16 to change the gear ratio setting. The ECU 31 also controls the actuators 18 and 29 of the transmission clutch 15 and the starting clutch 27.

By the way, in the vehicle control device of the present embodiment, the ECU 31 detects slow acceleration of the vehicle and acceleration of the enriched area (slow acceleration and enriched area acceleration detecting means).
When slow acceleration and enrichment region acceleration of the vehicle are detected, a target horsepower is calculated (target horsepower calculation means) according to the driving state at that time, and a target output and a target output for obtaining the target horsepower near the stoichiometric air-fuel ratio are obtained. The target rotation speed is set (target value setting means), and the speed ratio of the CVT 16 and the output of the engine 11 are controlled (control means) so as to achieve the set target output and target rotation speed. Specifically, C
The actual rotation speed of the input shaft (primary shaft 17) of the VT 16 is detected (rotation speed detection means), and the target output is corrected based on the target rotation speed and the actual rotation speed detected by the rotation speed detection means (target output correction means). Then, the output of the engine 11 is controlled based on the corrected target output.

Here, the control of the ECU 31 in the above-described vehicle control device according to the present embodiment will be described in detail with reference to the flowchart of FIG. 2 and the graph of FIG. 3 showing the change of the driving state during the slow acceleration and the enrichment region acceleration of the vehicle. Will be described.

As shown in FIG. 2, first, in step S1,
The accelerator detected by the accelerator position sensor 34
The opening APS and the engine speed detected by the engine speed sensor 32
The gin rotation speed Ne is read. And in step S2
Indicates that the accelerator opening APS is equal to a predetermined accelerator opening AP
S_SSmaller and the target air-fuel ratio KAF is 14.7
By detecting whether the vehicle speed is
The enrichment region acceleration is determined. In this case, the target sky
The fuel ratio KAF is based on the engine speed and the engine load Pe.
Required. Then, the accelerator opening APS is adjusted to a predetermined value.
Axel opening APS _SOr the target air-fuel ratio KAF
If it is 14.7 or higher, the vehicle accelerates rapidly or runs steadily
And the process proceeds to step S13 to
11 and CVT 16 are output controlled as usual.

On the other hand, in step S2, the accelerator opening APS is smaller than a predetermined accelerator opening degree APS _S, and, if the target air-fuel ratio KAF is smaller than 14.7, determined slow acceleration and enriched zone acceleration of the vehicle And step S3
Move to In this step S3, the target P which is the target average effective pressure of the engine 11 is
and e _1, reads the target Np ₁ is a target primary rotation speed of CVT16, calculates a target horsepower PS on the basis of the target Pe ₁ and the target Np _1. In this case, in the graph of FIG. 3, if the driver suddenly depresses the accelerator pedal too much from the acceleration start position at low rotation and low load of the engine 11,
The target Pe of the engine 11 is an enrich zone at a high load on the horsepower A curve. Therefore, in step S4, the target horsepower PS is set to the stoichiometric feedback SF.
/ B region (near the stoichiometric air-fuel ratio), the target Pe ₁
And the target Np ₁ are set to the target Pe ₂ and the target N on the horsepower A curve.
Change to p ₂ (acceleration position).

However, the ECU 31 determines that the target Pe_TwoAnd eyes
Standard Np_TwoDoes not cause a shift delay in CVT16
Therefore, the CVT 1 due to the shift delay of the CVT 16
6 caused a delay in the rotation of the primary shaft 17
Would. Therefore, during this time, the target Pe_TwoTo correct
Occurs due to a delay in the rotation of the primary shaft 17
It tries to suppress the decrease in horsepower. That is, step S
5, the CVT detected by the primary rotation speed sensor 35
16 actual rotation speed Np of the primary shaft 17 _rRead
In step S6, the actual rotational speed Np_rAnd target Np
_TwoIs calculated. Then, in step S7
The correction coefficient map shown in FIG.
To Pe correction coefficient K_Pe, And the target N
p_TwoTo the Pe correction coefficient K_Pe, The correction target P
e_aIs calculated. The correction target Pe thus obtained_a
And actual rotation speed Np_rIs the acceleration relay position shown in Fig. 3.
It is a place. This causes a shift delay of the CVT 16
Acceleration failure is prevented.

In step S9, this correction target
Pe_aAnd actual rotation speed Np_rAnd the target air-fuel ratio KAF_TSeeking
In step S10, the calculated target air-fuel ratio KAF_TBut
It is determined whether it is smaller than 14.7, that is, in FIG.
Whether or not the indicated acceleration relay position is in the enrich zone
Check. In this step S10, the target air-fuel ratio KAF
_TIs smaller than 14.7 and the acceleration relay position is enriched
If it is in the zone, in step S11, the target air-fuel ratio KA
F is set to 14.7 and the actual rotational speed Np _rBy
The target Pe is set. This reduces the horsepower
Although the feeling of acceleration is slightly worse, it enters the enriched region
This prevents the fuel economy from deteriorating. On the other hand,
In step S10, the target air-fuel ratio KAF_TIs 14.7 or more
If the fast relay position is in the SF / B zone, step S
At 12, the target air-fuel ratio KAF is corrected to the target Pe._aAnd actual rotation
Number Np_rTarget air-fuel ratio KAF calculated from_TIf set to
Together, target Pe_aIs set as the target Pe. And settings
Engine based on the target air-fuel ratio KAF and the target Pe
11 is controlled.

Therefore, during shifting of the CVT 16 during slow acceleration of the vehicle and acceleration in the enriched region, the vehicle shifts from the acceleration start position to the acceleration position via the acceleration relay position in the SF / B zone. Then, from this acceleration position, the engine speed Ne (primary speed Np) and the engine load Pe rise and shift on the horsepower B curve.

As described above, in the vehicle control device of the present embodiment, when the slow acceleration and the enrichment region acceleration of the vehicle are detected, the target Pe of the engine 11 for obtaining the target horsepower PS near the stoichiometric air-fuel ratio is obtained. ₂ and the target Np ₂ of the CVT 16 are set, the operating state of the engine 11 does not enter the enrich zone, and deterioration of fuel efficiency due to inadvertent acceleration of the driver due to excessive depression of the accelerator pedal is prevented. In this case, to detect the actual rotational speed Np _r of the primary shaft 17 of CVT16, the actual rotational speed N
seeking Pe correction coefficient K _Pe based on the deviation ΔNp the p _r and the target Np _2, target Np ₂ This Pe correction coefficient K _Pe
Is corrected, and acceleration drivability can be prevented to improve drivability.

In the above-described embodiment, the gradual acceleration of the vehicle is determined based on the accelerator opening APS. However, the rate of change of the accelerator opening may be used instead of the accelerator opening APS, or the throttle opening may be determined. May be used. Furthermore, although the target air-fuel ratio KAF _T had an upper limit value such that the near stoichiometric, in the case where poor acceleration is considered greater may delete the upper limit setting. Furthermore, in the above-described embodiment, the target Np or the like may be set so as to be S / F / B, and in particular, it may not be feedback control, and It may be a lean air-fuel ratio. In the above-described embodiment, the belt-type CVT 16 is used as the continuously variable transmission.
However, another type of continuously variable transmission such as a toroidal type CVT may be used.

[0028]

As described in detail in the above embodiment, according to the vehicle control apparatus of the first aspect of the present invention, the target horsepower calculated according to the driving state at the time of slow acceleration of the vehicle and acceleration in the enrichment region. The target output and the target rotational speed are set so as to obtain near the stoichiometric air-fuel ratio, and the speed ratio of the continuously variable transmission and the output of the internal combustion engine are controlled so that the set target output and the target rotational speed are obtained. Therefore, the operating state of the internal combustion engine does not enter the enriched zone, and it is possible to prevent deterioration of fuel efficiency due to inadvertent acceleration of the driver due to excessive depression of the accelerator pedal.

Further, according to the vehicle control apparatus of the present invention, the actual rotational speed of the input shaft of the continuously variable transmission is detected, and the target output is corrected based on the target rotational speed and the actual rotational speed. Since the output of the internal combustion engine is controlled based on the corrected target output, acceleration failure can be prevented and drivability can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a vehicle control device according to an embodiment of the present invention.

FIG. 2 is a flowchart of CVT output control by the vehicle control device according to the embodiment.

FIG. 3 is a graph showing a primary rotation speed and an engine load when the vehicle is slowly accelerated.

FIG. 4 is a graph showing a correction coefficient for a primary rotational speed deviation.

FIG. 5 is a graph showing an operating state of a vehicle having an engine and a CVT by a conventional control device.

[Explanation of symbols]

Reference Signs List 11 engine (internal combustion engine) 16 CVT (type continuously variable transmission) 17 primary shaft 23 regulator valve 24 gear ratio control valve 31 electronic circuit unit for engine, ECU (target horsepower calculation means, target value setting means, control means, target output) Correction means) 32 engine speed sensor 33 vehicle speed sensor 34 accelerator position sensor 35 primary speed sensor (rotation speed detecting means)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI theme coat ゛ (reference) F16H 59:38 F16H 59:38 F term (reference) 3D041 AA26 AA32 AA66 AB01 AC01 AC08 AC19 AC20 AD02 AD10 AD23 AD31 AD51 AE07 AE09 AE14 AE31 AE36 AF01 AF09 3G093 AA06 BA15 BA19 CB06 DA01 DA06 DB01 DB05 DB11 EA05 EA13 EB03 FA07 FA08 FA10 3J052 AA14 CA21 EA04 FB33 GC13 GC23 GC36 GC44 GC46 GC72 HA11 BA01 CA01 LA01 3J067 AB01

Claims (2)

[Claims] In a control apparatus for a vehicle having an internal combustion engine and a continuously variable transmission, a slow acceleration detecting means for detecting a slow acceleration of the vehicle, and a target air-fuel ratio setting means for setting a target air-fuel ratio at the time of the slow acceleration When the slow acceleration detection means detects slow acceleration of the vehicle and the target air-fuel ratio set by the target air-fuel ratio setting means is more enriched than the stoichiometric air-fuel ratio, the target horsepower is adjusted according to the driving state. Target horsepower calculating means for calculating, target output setting means for setting a target output and a target rotation speed for obtaining the target horsepower calculated by the target horsepower calculating means near the stoichiometric air-fuel ratio, and setting by the target value setting means. And a control means for controlling a speed ratio of the continuously variable transmission and an output of the internal combustion engine so that the target output and the target rotation speed are obtained. 2. A control device for a vehicle according to claim 1, wherein said rotational speed detecting means detects an actual rotational speed of an input shaft of said continuously variable transmission, and said target rotational speed and said rotational speed detecting means detect the actual rotational speed. Target output correction means for correcting the target output based on the actual rotation speed, the control means,
A control device for a vehicle, wherein the output of the internal combustion engine is controlled based on the target output corrected by the target output correction means.