JP3228094B2 - Transmission control device for continuously variable transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a shift control device for a continuously variable transmission mounted on a vehicle.

[0002]

2. Description of the Related Art Conventionally, a V-belt type or a toroidal type (friction wheel type) has been known as a continuously variable transmission used for vehicles such as automobiles, and a transmission control device for such a continuously variable transmission. Then, based on the throttle opening of the engine (or the accelerator opening, the same applies hereinafter) and the vehicle speed, a target value of the number of revolutions input to the continuously variable transmission is set, and the gear ratio according to this target number of revolutions is obtained. Such a control is known.

In the above-described transmission control apparatus for a continuously variable transmission, as the throttle opening is smaller, the gear ratio is set to a higher speed side (the target input rotation speed is smaller). Since the ratio is set to the low speed side (the target input rotation speed is large), the throttle opening decreases when the driver releases the accelerator pedal during downhill running, and the gear ratio is set to the high speed side to set the target speed. Since the input speed decreases, the engine brake is controlled in a direction in which it does not work. For this reason, the driver may feel an extra feeling of acceleration despite releasing the accelerator pedal, and the frequency of the brake operation may increase during downhill traveling, which may increase the consumption of the braking device. Conceivable.

Japanese Patent Application Laid-Open No. 6-819 discloses a technique for reducing frequent brake operations during coasting on a downhill.
No. 32 is known, which is to set the lower limit value of the target input rotation speed of the continuously variable transmission in accordance with the increase of the absolute value of the weight gradient resistance of the vehicle, and to positively apply the engine brake. Is operated.

[0005]

However, in the above-mentioned conventional shift control device, the lower limit of the target input rotational speed is set to a large value in accordance with the increase in the absolute value of the weight gradient resistance of the vehicle. When the coasting is performed with the accelerator pedal released on a downhill that is not the target, the target input speed changes frequently according to the change in the gradient, so in addition to the engine speed constantly changing, if the gradient decreases The engine brake suddenly decreases, and if the gradient increases, the engine brake rapidly increases, and the deceleration changes rapidly and stepwise according to the gradient, which may give the driver discomfort or discomfort. As shown in the figure, while the accelerator pedal is released, the gradient turns to an uphill during the downhill during coasting with the accelerator pedal released, and the gradient of this uphill is equal to the absolute value of the weight gradient resistance of the downhill. Or if such as the increase,
From slope uphill to turn the time t ₁ later, in order to increase the absolute value of the weight grade resistance is equal, because the target input rotational speed remains likewise larger correction and downhill, the engine brake is rapidly increasing vehicle There has been a problem in that the deceleration becomes excessively large, giving the driver discomfort and discomfort.

Accordingly, the present invention has been made in view of the above-mentioned problems, and prevents a sudden increase in deceleration even if the vehicle turns from a downhill to an uphill during coasting, thereby causing the driver to feel uncomfortable or uncomfortable. It is an object of the present invention to provide a shift control device of a continuously variable transmission that can smoothly coast without causing discomfort.

[0007]

According to a first aspect of the present invention, as shown in FIG. 18, a speed ratio changing means 5 for changing a speed ratio of a continuously variable transmission 2 and a continuously variable transmission according to a driving state of a vehicle. Transmission control means 51 for calculating a target input rotation speed of the input shaft of the machine and controlling the speed ratio changing means 5 so that the input shaft rotation speed matches the target input rotation speed. In the shift control device, the deceleration detecting means 51 for detecting the deceleration of the vehicle, the opening degree detecting means 52 for detecting the operation state of the accelerator pedal, and the opening degree detecting means for detecting the release of the accelerator pedal. The detected deceleration and
Deceleration comparing means 53 for comparing with a preset constant velocity region
And a correction amount for calculating a correction amount per a predetermined unit time for correcting the target input rotation speed to be small when the deceleration exceeds a preset constant speed region , in accordance with a detected value of the deceleration. The speed change control means 50 includes a calculating means 54 and a corrected target input rotational speed setting means 55 for subtracting the correction amount from the target input rotational speed. The shift control means 50 changes the gear ratio based on the corrected target input rotational speed. Control means 5.

In a second aspect based on the first aspect, the correction amount calculating means increases the absolute value of the correction amount per a predetermined unit time according to the magnitude of the deceleration.

In a third aspect based on the first or second aspect, the correction amount calculating means sets the correction amount per predetermined unit time to zero or substantially zero when the deceleration is equal to or less than a predetermined value. I do.

In a fourth aspect based on the first aspect, the correction amount calculating means compares the deceleration with a second threshold value and sets the deceleration to a second threshold value. Is exceeded, the correction amount per predetermined unit time is set substantially constant regardless of the magnitude of the deceleration.

[0011]

According to the first aspect of the present invention, the transmission control means controls the transmission ratio changing means such that the input shaft rotation speed of the continuously variable transmission matches the target input rotation speed according to the driving state of the vehicle. However, when the driver releases the accelerator pedal, if the deceleration of the vehicle exceeds a preset constant velocity range , a correction amount per predetermined unit time is calculated according to the deceleration, The gear ratio is changed according to the corrected target input speed. Since the target input rotation speed changes continuously by reducing the correction amount per unit time, the engine braking force can be continuously reduced according to the deceleration, and the coasting is performed with the accelerator pedal released. When the gradient changes from a downhill to an uphill, the engine braking force according to the driver's expectations is continuously changed while suppressing a sudden change in deceleration, and smooth coasting without discomfort is felt. It can be performed.

According to a second aspect of the present invention, the correction amount calculating means increases the absolute value of the correction amount per a predetermined time in accordance with the magnitude of the deceleration. If the deceleration increases when changing from a downhill to an uphill, the corrected target input speed can be reduced quickly to increase the speed at which the engine braking force is weakened, giving the driver an uncomfortable feeling. The deceleration can be performed while continuously changing the engine braking force without giving.

In the third invention, the correction amount per unit time is set to zero or almost zero when the deceleration is equal to or less than a predetermined value. The input rotation speed hardly decreases, and the vehicle gradually decelerates.However, when coasting on a gentle uphill where the deceleration is equal to or less than a predetermined value with the accelerator pedal released, the target input rotation speed is reduced. By suppressing the fluctuation, it is possible to prevent a sense of incongruity and realize coasting as expected by the driver.

According to a fourth aspect of the present invention, when the deceleration exceeds a second predetermined value, the correction amount per unit time for decreasing the target input rotation speed becomes substantially constant, and the gradient during coasting becomes large. When turning from a downhill to an uphill or a flat road, it is possible to prevent a sense of speed increase of the vehicle due to a sharp decrease in the target input speed, and to continuously control the engine braking force according to the driver's expectation. .

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, a continuously variable transmission 2 (C in the figure)
VT) is set to a predetermined speed ratio according to the driving state of the vehicle by the speed ratio changing means 5 controlled by the speed change controller 7. The continuously variable transmission 2 is, for example, a V-belt type or a toroidal type. It is composed of expressions.

The shift control controller 7 is mainly composed of a microprocessor or the like, and has a vehicle speed sensor 8 for detecting a vehicle speed VSP, a throttle opening sensor 9 for detecting a throttle opening TVO, a driving wheel rotation sensor 11, a braking device. Brake switch 12 for detecting the operating state of the vehicle, a vehicle acceleration sensor 14 for detecting the longitudinal acceleration G of the vehicle, an idle switch 15 for detecting the released state of the accelerator pedal, and detecting the rotational speed No of the output shaft of the continuously variable transmission 2. As means for detecting the output shaft rotation sensor 13 and the input shaft rotation speed Ni of the continuously variable transmission 2, the driving is performed based on a signal indicating the driving state of the vehicle input from the engine rotation sensor 10 which detects the engine rotation speed Ne. Control target input rotation speed D according to state
In addition to calculating SRREV, a target gear ratio DSRRTO is instructed to a gear ratio changing means 5 composed of an actuator or the like so that the input shaft rotational speed = engine rotational speed Ne matches the target input rotational speed. The driving force from the engine 1 is transmitted to the drive shaft 3 coupled with the drive shaft 3.

In this embodiment, the case where the engine 1 is directly connected to the input shaft of the continuously variable transmission 2 is shown, and the engine speed Ne is equal to the input shaft speed Ni. When a speed reduction mechanism, a torque converter, or the like is interposed between the transmission 2 and the input shaft, an input shaft rotation sensor may be provided, and the detected value may be set as the input shaft rotation speed Ni.

The transmission control controller 7 is also connected to an engine control controller 6 for controlling the engine 1 according to the driving state of the vehicle, and sends a transmission ratio control signal and the like from the transmission control controller 7 to the engine control controller 6. On the other hand, various operation information such as fuel injection cut-off is transmitted from the engine controller 6 and the engine 1
And the speed change controller 7 constitute an integrated control system that is controlled synchronously.

The engine controller 6 performs supercharging pressure control and the like in addition to fuel injection control from the fuel injection nozzle 4 and ignition timing control in accordance with the operating state of the vehicle. The control is the throttle opening TV
O, engine speed Ne, intake air amount, etc.
In addition to the air-fuel ratio feedback control, when the throttle is fully closed, fuel cut is performed at a predetermined engine speed or higher, and when the throttle is fully closed, control such as fuel injection recovery is performed. In the present embodiment, a case is shown in which the engine 1 is configured by a spark ignition type internal combustion engine.

An example of the control performed by the shift control controller 7 is shown in the flowcharts of FIGS. 2 to 10, and the details of the control will be described in detail with reference to these flowcharts.

Here, FIG. 2 is a diagram showing a state where the time is predetermined, for example, 5 ms.
An outline of a main routine of the shift control executed for each ec is shown. FIG. 3 and subsequent drawings show a subroutine for performing an engine brake correction during downhill traveling or the like. Will be described in detail.

[1. Shift control] In the main routine of FIG. 2, first, in step S1, the operating state of the vehicle is read from the above-described sensors and the like, and in step S2, the throttle opening TVO and the vehicle speed V read in step S1 are read.
Based on the SP, a control target input rotation speed DSRREV which is a target value of the input shaft rotation speed Ni (= engine rotation speed Ne) of the continuously variable transmission 2 is calculated from the shift map shown in FIG.

In step S3, a later-described step S1 is executed.
0, the control target input rotation speed DSRRE when the engine brake is operated according to the longitudinal acceleration G applied to the vehicle.
V is corrected.

In step S4, the control target input rotational speed DSRREV after the correction by the engine brake is performed.
And the target speed ratio DS so that the input shaft speed Ni matches.
RRTO is calculated, and in step S5, a control signal is output to the speed ratio changing means 5 of the continuously variable transmission 2 so that the continuously variable transmission 2
Control the transmission gear ratio.

[2. Engine Brake Correction Control] The flowchart of FIG. 3 shows the outline of the subroutine of the engine brake correction control performed in step S3, and the details of this subroutine are configured as shown in the flowcharts of FIGS. First, the outline of the engine brake correction control will be described.

In step S10, the control target input rotational speed DSRRE obtained in step S2 of the main routine is determined.
V, the input shaft speed Ni of the continuously variable transmission 2 (hereinafter, referred to as Ni).
(Hereinafter simply referred to as the input shaft rotation speed) is determined.

In step S11, the longitudinal acceleration of the vehicle (hereinafter referred to as "the vehicle acceleration") is determined in order to determine whether the engine brake needs to be further strengthened or needs to be weakened.
The threshold value is simply calculated as acceleration or deceleration.

In step S12, the acceleration generated in the vehicle is detected, and the magnitude of the acceleration is compared with the threshold value obtained in step S11 to determine whether the engine brake is to be further strengthened or further reduced. Is determined based on the operation state of the accelerator pedal.

In step S13, a correction amount of the target input rotational speed per unit time, which is a speed at which the engine braking force is changed, is calculated according to the magnitude of the acceleration obtained in step S12.

Then, in step S14, step S
13, a corrected target input rotation speed DS for generating an engine braking force corresponding to the acceleration based on the correction amount obtained in step 13.
RENBR is calculated, and in step S15, the corrected target input rotation speed DSRENBR is changed to the control target input rotation speed DSRRE.
After newly setting V, the process returns to the main routine after step S4, and the target speed ratio DSRRTO is calculated from the control target input rotation speed DSRREV to which the engine brake correction has been added.

Hereinafter, the details of the engine brake correction control will be described with reference to the flowcharts of FIGS.

[2.1 Determination of Correction Range of Control Target Input Rotational Speed and Acceleration Threshold] FIG. 4 shows a subroutine process performed in step S3 shown in the main routine of FIG. 2, and steps S101 to S104. Corresponds to steps S10 and S11 in the outline shown in FIG.

In step S101, based on the vehicle speed VSP read in step S1, the upper limit input rotation speed DSR which is the upper limit value of the correction control range is obtained from the map shown in FIG.
Calculate HLMT. The map shown in FIG. 11 is a map in which the input rotation speed corresponding to the vehicle speed VSP is set in advance using the throttle opening TVO as a parameter, and is stored in a storage means such as a ROM (not shown) of the shift control controller 7. .

On the other hand, in step S102, similarly,
Lower limit input rotation speed DSRHL which is the lower limit value of the correction control range
MT is calculated based on the vehicle speed VSP.

Next, in steps S103 and S104, in order to determine whether the engine brake needs to be further strengthened or needs to be further weakened, FIG.
Based on the map shown in FIG. 2, a threshold VSPOVLM on the acceleration side and a threshold VSPUDL on the deceleration side
M is calculated according to the vehicle speed VSP.

The map shown in FIG. 12 is set in advance according to the sensible acceleration expected by the driver when the accelerator pedal is released (idle switch 15 = ON), and changes according to the speed. The constant velocity region is set around a constant velocity region having a predetermined acceleration range. This constant velocity region does not indicate a physical constant velocity (acceleration = 0 G), and when the accelerator pedal is released, the driver Is an area where the driver feels that the vehicle is traveling at a substantially constant speed. An acceleration area in which the driver experiences the acceleration of the vehicle above the constant velocity area, and a driver experiences the deceleration of the vehicle below the constant velocity area. The deceleration range is defined, and the boundary between the constant speed range and the acceleration range is the acceleration-side threshold VSPOVLM.
The boundary between the constant speed range and the deceleration range is the deceleration side threshold VSPUDLM.
It is.

An example in which an idle switch 15 is used as an opening degree detecting means for detecting an operation state of an accelerator pedal will be described. In a spark ignition type internal combustion engine such as a gasoline-powered car or a gas-fueled car, the throttle opening TVO is used. Thus, the release state of the accelerator pedal may be detected.

As described above, in steps S101 to S104, the upper limit input speed DSRHLMT, the lower limit input speed DSRLLMT of the correction control range, and the acceleration / deceleration threshold value VSPO
After setting VLM and VSPUDLM, the process proceeds to the acceleration / deceleration determination process in step S110 shown in FIG.

[2.2 Acceleration / Deceleration Judgment Processing] In steps S110 to S118 of FIG. 5, it is determined in which area the current vehicle acceleration is in the map of FIG. Step S12.

First, in step S111, it is determined whether or not the vehicle speed VSP read in step S1 is in a predetermined low-speed region, for example, 10 km / h or less. Acceleration TKRAM
While S6 is set to 0, if not, the process proceeds to step S112.

[0042] In step S112, the acceleration of the vehicle before the current vehicle speed VSP and predetermined time, for example, 5 cycles ago (50 msec ago) vehicle acceleration (deceleration) from the difference of the vehicle speed VSP _-5 in seeking TKRAMS6. Although the case where the differential value of the vehicle speed VSP is used as the deceleration detecting means is shown, the differential value of the detection value G of the vehicle acceleration sensor 14 or the detection value of the driving wheel rotation sensor 11 may be used.

Next, in step S113, the vehicle acceleration TKRAMS6 is compared with the acceleration-side threshold value VSPOVLM obtained in step S103, and the vehicle acceleration TKR is calculated.
If AMS6 is larger than threshold value VSPOVLM, it is determined that the current vehicle acceleration TKRAMS6 is in the acceleration region where the engine brake needs to be increased in the map shown in FIG. 12, and the process proceeds to step S117.
The acceleration flag VSPPLS is set to 1; otherwise, the process proceeds to step S114 to determine whether the vehicle is in the deceleration range.

In step S114, the vehicle acceleration TKRA
If MS6 is smaller than the deceleration side threshold value VSPUDLM obtained in step S104, it is determined that the engine brake needs to be weakened, and the flow advances to step S116 to set the deceleration flag VSPMNS to 1; Is determined to be in the constant velocity region of FIG. 12, and the process proceeds to step S115 to set 1 to the constant velocity flag VSPEQS. In step S118, the vehicle acceleration TKRA
Also in the case of the low speed range where MS6 = 0, step S11 is performed.
At 5, the constant speed flag is set to 1.

Thus, the threshold values VSPOVLM, VS
By comparing the PUDLM with the vehicle acceleration TKRAMS6, the region of the vehicle acceleration in the map of FIG. 12 is identified by the acceleration, deceleration, and constant speed flags. After that, the process proceeds to step S120 of FIG. The search for the correction amount of the target input rotation speed and the mode division according to the accelerator pedal operation are performed.

[2.3 Target Input Rotational Speed Correction Amount Setting, Mode Separation According to Driving Operation] Steps S120 to S120 in FIG.
In step S131, after setting the correction amount of the target input rotation speed according to the vehicle acceleration TKRAMS6, the operation state of the accelerator pedal, that is, the case according to the driver's intention is divided, and step S13 in the flowchart of FIG. Is equivalent to

In steps S121 and S122, FIG.
The correction amount of the target input rotation speed per unit time is obtained as the downshift correction amount DDSRDN or the upshift correction amount DDSRUP according to the magnitude and sign of the vehicle acceleration TKRAMS6 from the map shown in FIG.

When the vehicle acceleration TKRAMS6 is positive, the downshift correction amount DDSRDN in the direction of increasing the target input speed is used to increase the engine braking force.
However, when the vehicle acceleration TKRAMS6 is negative, the upshift correction amount DDSRUP in the direction of decreasing the target input speed is selected to reduce the engine braking force,
Here, the predetermined unit time indicates a processing execution interval, and in this case, indicates a target input rotation speed correction amount every 5 msec.

The map shown in FIG. 13 is set in advance based on experiments conducted by the applicant of the present invention, as described later, and is stored in a storage means (not shown) of the shift control controller 7 such as a ROM.

Next, in steps S123 to S131,
The intention of the driver to accelerate or decelerate is estimated from the change between the previous value and the current value of the operation state of the accelerator pedal, and the cases are classified.

First, in step S123, it is determined whether or not the flag OLDIDLE indicating the status of the idle switch 15 is 0 in the previous process (5 msec before), that is, whether or not the accelerator pedal is depressed. If it is released to step S124, (OLDIDL
E = 1) Proceed to step S125.

In step S124, whether the flag IDLE indicating the current state of the idle switch 15 is 0,
That is, it is determined whether the accelerator pedal is depressed,
If it has been depressed, the process proceeds to step S126. If it has been released (IDLE = 1), the process proceeds to step S127.

In step S126, the accelerator pedal is continuously depressed in both the previous time and the present, and the idle switch 15 is in the OFF and OFF states, and the process proceeds to step S150 described later.

On the other hand, if it is determined in step S124 that the accelerator pedal is currently released, the depressed state of the accelerator pedal has changed from the previous value. In step S127, the current state of the idle switch 15 is changed to OLDIDLE = In step S128, the idle switch 15 is changed from OFF to ON, and it is determined that the accelerator pedal that has been depressed is released, and the process proceeds to step S160.

On the other hand, the previous idle switch 15 was turned on.
Also in step S125, similarly to the above, it is determined whether the flag IDLE indicating the current state of the idle switch 15 is 0, that is, whether the accelerator pedal is depressed, and if it is depressed, the process proceeds to step S130. If it has been released (IDLE = 1), the process proceeds to step S129.

In step S129, since the accelerator pedal is continuously released, step S1 is performed without changing the previous idle switch flag OLDIDLE.
Release 40 and proceed to processing.

On the other hand, if it is determined in step S125 that the accelerator pedal is currently depressed, the depression state of the accelerator pedal has changed from the previous value.
In step S130, the current status of the idle switch 15 is updated as OLDIDLE = 0, and step S131 is performed.
Then, the idle switch 15 changes from ON to OFF,
It is determined that the released accelerator pedal is depressed, and the process proceeds to step S150.

By comparing the previous value OLDIDLE of the idle switch 15 with the current value IDLE in this manner, the change in the depression state of the accelerator pedal is determined in step S.
The correction of the target input rotation speed is performed for each of the three cases of 140, 150, and 160, and these steps S140 are performed.
The following corresponds to step S14 in FIG.

Although the operation of the accelerator pedal is detected by the idle switch 15 in the above description, the operation may be performed based on the detection value TVO of the throttle opening sensor 9.

[2.4 When the accelerator pedal is continuously released] FIG. 7 shows that the idle switch 15
Step S141 shows a process of correcting the target input rotational speed when the accelerator pedal whose current value is ON is continuously released.
Then, it is determined whether or not the acceleration flag VSPPLS set in steps S110 to S118 is 1, and if it is 1, the current vehicle acceleration is in the acceleration range of the map in FIG. , 0, the process proceeds to step S142.

In step S143, the downshift correction amount DDSRDN obtained in step S121 in FIG. 6 is input to the correction target input in order to increase the engine braking force to reduce the vehicle acceleration from the acceleration range in FIG. 12 to the constant speed range. The target input speed is increased by adding to the previous value of the speed DSRENBR.

DSRENBR = DSRENBR ₋₁ + DDSRDN Note that “ ₋₁ ” indicates the previous value. The same applies hereinafter.

Then, in step S144, a correction control flag NOWCNT indicating that the correction control is being performed is set to 1, and the process proceeds to the rotation check in step S170.

On the other hand, if it is determined in step S141 that the vehicle is not in the acceleration range, the flow advances to step S142 to determine whether or not correction control is being performed.
The process proceeds to 45 to determine whether or not the vehicle is in the deceleration range. If the correction control is not being performed, the process proceeds to step S146.

In step S146, since it is not necessary to correct the target input rotation speed, the corrected target input rotation speed DSREN is used.
BR is set to the control target input rotation speed DSRREV obtained in step S2 of FIG. 2 and the process proceeds to step S170.

In step S145, it is determined whether or not the deceleration flag VSPMNS has been set in step S116 in FIG. 5 described above. If the current vehicle acceleration is in the deceleration range of the map shown in FIG. If not, the process proceeds to step S170.

In step S147, the output signal BRK of the brake switch 12 determines whether or not the brake is being depressed.
Determined by If the brake is not depressed (BR
K = 0), the process proceeds to step S148 to perform the correction process in the deceleration range, while the brake is being depressed (BR
In K = 1), even in the deceleration range where the engine brake needs to be weakened, the deceleration range is corrected in order to prohibit the target input rotation speed from being corrected small and give priority to the driver's braking operation. Instead, proceed to step 170.

In step S148, the upshift correction amount DDSRUP obtained in step S122 in FIG. 6 is used to correct the target input rotational speed DSREN in order to weaken the engine brake and increase the speed from the deceleration range shown in FIG. 12 to the constant speed range.
The target input rotation speed is gradually reduced by subtracting from the previous value of BR (as shown in FIG. 13, the upshift correction amount DD
Since SRUP has a negative value, the correction target input rotation speed DSRENBR is subtracted by adding this.

DSRENBR = DSRENBR ₋₁ + DDSRUP Then, the process proceeds to rotation check in step S 170.

[2.5 When the Accelerator Pedal is Depressed] Steps S150 to S155 in FIG. 8 are performed at the moment when the accelerator pedal at which the current value of the idle switch 15 is turned off is depressed or when the depression is continued. 4 shows a number correction process.

In step S151, it is determined from the state of the correction control in-progress flag NOWCNT whether or not the target input rotational speed is currently being subjected to correction control. If the correction control is being performed, the process proceeds to step S152. Proceed to step S153.

In step S152, the corrected target input rotation speed DSRENBR _{-1 of the} previous process and the current control target input rotation speed DSRREV obtained in step S2 of FIG.
When the control target input rotation speed DSRREV is equal to or less than the previous correction target input rotation speed DSRENBR _-1 , the process proceeds to step S154. Otherwise, the process proceeds to step S153.

In step S154, a value obtained by subtracting a predetermined value from the previous corrected target input speed DSRENBR _-1 and slightly lowering the target input speed is set as the current corrected target input speed DSRENBR as follows. , DSRENBR = DSRENBR _-1 -1 In this case, the correction target input rotational speed DSRENBR is set to 1 rp.
m, the corrected target input rotational speed DSRENBR is gradually approached to the control target input rotational speed DSRREV, and the process proceeds to step S171 without the rotation limiter.

On the other hand, in step S153, the correction control flag N is set to end the engine brake correction control.
After resetting OWCNT to 0, step S155
To the corrected target input rotational speed DSRENBR in step S
The control target input rotation speed DSRREV obtained in step 2 is stored,
The process proceeds to step S171 as described above.

[2.6 When the Accelerator Pedal is Released] Steps S160 to S164 in FIG. 9 correspond to the target input rotational speed at the moment when the accelerator pedal is released when the previous value of the idle switch 15 is OFF and the current value is ON. 4 shows a correction process.

In step S161, the correction target input rotation speed DSRENBR _{-1 of the} previous process and the upper limit input rotation speed DS of the correction control range obtained in step S101 of FIG.
RHLMT and the previous corrected target input rotational speed D
When SRENBR _-1 exceeds the upper limit input rotation speed DSRHLMT, the process proceeds to step S162, while when SRENBR _-1 is equal to or lower than the upper limit input rotation speed DSRHLMT, step S163 is performed.
Proceed to.

In step S162, the upper limit input rotation speed DSRHLMT of the correction control range is set as the correction target input rotation speed DSRENBR, and then the flow proceeds to the rotation check processing in step S170.

On the other hand, if the rotational speed is equal to or lower than the upper limit input rotational speed DSRHLMT, it is determined in step S163 whether the correction control is being performed . If the correction control is not being performed, step S164 is performed .
Then, the control target input speed DSRREV is set to the corrected target input speed DSRENBR, and step S170 is performed.
Proceeds to step S17 if the correction control is being performed.
Proceed to process 0.

[2.7 New Control Target Input Speed DSRR
EV setting] In this way, in the above 2.4 to 2.6, the operation state of the accelerator pedal is divided into three cases, and the corrected target input rotation speed DSRENBR is set, and then the process proceeds to step S170 or S171, and the engine is started. The setting of the control target input rotation speed DSRREV after the brake correction control is performed in and after step S170 in FIG.
Steps 170 and after correspond to step S15 in FIG.

When the process proceeds to the rotation checking process in step S170, it is determined in step S172 whether the corrected target input speed DSRENBR is equal to or less than the lower limit input speed DSRLLMT of the correction control range obtained in step S102 in FIG. If it is determined that the corrected target input rotation speed DSRENBR is equal to or lower than the lower limit input rotation speed, the process proceeds to step S173. Otherwise, the process proceeds to step S175.

In step S173, after the lower limit input rotation speed DSRLLMT of the correction control range is newly set as the correction target input rotation speed DSRENBR, the correction control flag NOWCNT is reset to 0 to end the correction control, and then step S177 is performed. Proceed to.

On the other hand, in step S172, the corrected target input speed DSRENBR is set to the lower limit input speed DSRL.
If it exceeds LMT, in step S175, the upper limit input rotational speed D of the correction control range obtained in step S101 described above.
It is determined whether or not SRHLMT has been exceeded, and if so, a new corrected target input rotational speed D is determined in step S176.
Upper limit input speed DS of correction control range as SRENBR
After setting the RHLMT, the process proceeds to step S177.

From the above process [2.5] to step S1
If the process has proceeded to the process 71 without the rotation limiter, the process directly proceeds to step S177.

In step S177, the correction target input rotation speed DSR set by the engine brake correction control is set.
ENBR is set as a new control target input rotation speed DSRREV, and the process returns to step S4 in FIG. Thus, the speed ratio changing means 5 of the continuously variable transmission 2 is driven such that the target speed ratio DSRRTO corresponding to the corrected target input rotational speed DSRENBR after the engine brake correction control is achieved.

[3. Setting of Upshift Correction Amount DDSRUP Map] Here, the upshift correction amount DDSRUP selected when the vehicle acceleration TKRAMS6 is negative.
Has a negative value as shown in FIG. 13, but is not directly proportional to the vehicle acceleration (hereinafter, deceleration), but is set by an experiment by the applicant of the present invention.

According to an experiment, when the vehicle is coasting downhill with the accelerator pedal released, the deceleration expected by the driver changes according to the magnitude of the vehicle deceleration.

In FIG. 14, a deceleration region where the vehicle acceleration is negative, a deceleration region A where the vehicle deceleration is very small, that is, an acceleration ≒ 0, and a deceleration that the driver experiences gradually increase. The deceleration area B is divided into three areas: a deceleration area B of a certain degree, and a deceleration area C in which the acceleration at which the driver's perceived deceleration increases as if braking is applied to the vehicle is further reduced. Speed = The amount of decrease in the target input speed was considered.

3. A In the deceleration region A in which the deceleration (acceleration <0) is equal to or greater than a predetermined value close to 0, the driver feels frequent changes in the engine speed (= target input speed) as annoying, as indicated by the broken line in the figure. If the upshift correction amount DDSRUP is directly proportional to the deceleration, the fluctuation of the target input speed becomes excessively sensitive to the fluctuation of the deceleration, and the acceleration and deceleration are frequently repeated, and the driver feels a sense of discomfort. In addition, in the deceleration region A, the driver hardly expects deceleration even when the accelerator pedal is released, and therefore, when the deceleration is equal to or more than a predetermined value near 0, the correction amount for decreasing the target input rotational speed per unit time. Is significantly increased from that in direct proportion shown by the broken line in the figure, and the upshift correction amount DDSRUP is 0 or almost 0.
Set so that

3. B In the deceleration region B exceeding the predetermined value where the deceleration is moderate,
For example, when the vehicle changes from a downhill to a steep ascending gradient, and the vehicle speed suddenly decreases and it feels as if braking has started, so the engine braking force should be reduced early to maintain the vehicle speed. It is. However, when the deceleration is directly proportional to the deceleration as shown by the broken line in the figure, the decrease in the engine brake is delayed, and the driver may feel blur. Therefore, the upshift correction amount DDSRUP is set to 0 or almost 0 in the deceleration region A. , The absolute value of the correction amount DDSRUP per unit time is set to be large continuously according to the large difference of the deceleration, and the correction amount is set slightly smaller than the graph indicated by the broken line in direct proportion to the deceleration, After increasing the speed at which the engine brake force is weakened, the upshift correction amount DDSRUP is continuously reduced so that the amount of decrease in the engine brake force changes more gently than in direct proportion, so that engine braking can be performed quickly and smoothly. Decrease power.

3. C In a deceleration region C in which the deceleration exceeds the second predetermined value, there are cases where the vehicle has turned from a steep downhill to a steep uphill or a flat road, and the downhill slope before the uphill slope is extremely small. Even if it is large, if the target input speed is reduced in proportion to the deceleration as shown by the broken line in the figure, the engine braking force will suddenly decrease, and the vehicle will feel like it is accelerating and rushing. There is.

Therefore, the upshift correction amount DDSRUP in this region C is substantially constant or gradually decreases from the above region B (the absolute value increases). Is set to be small, and when turning from a steep downhill to an uphill, the deceleration is continuously changed while preventing the feeling of rushing of the vehicle, and the speed at which the deceleration is weakened is almost constant Alternatively, it gradually increases in accordance with the magnitude of the deceleration.

In this way, the above 3. A-3. From C, the upshift correction amount DDSRUP is set so as to change continuously according to the driver's intention to decelerate, which changes according to the magnitude of deceleration, and according to the magnitude of deceleration.
In this embodiment, the upshift correction amount DDSRU
Although P is stored in the storage means of the shift control controller 7 as a map, it may be set as a function or the like.

[4. Overall action) Since the slope of a general slope is not constant, and there are irregularities on the road surface and subtle changes in the slope, if the accelerator pedal is continuously released and the vehicle is coasting downhill, the acceleration generated in the vehicle may fluctuate. for many, for example, as shown in FIG. 15, the downhill such that there is partial ascent in the middle of the downhill, the deceleration at time t ₁ for inverting the gradient uphill increases sharply, the engine brake Need to be weakened quickly.

When the deceleration increases and the vehicle enters the deceleration range of the map shown in FIG. 12, the deceleration flag VSPMNS is set in step S116 in FIG.
In order to reduce RENBR, an upshift correction amount DDSRUP, which is a decrease value per unit time, is obtained from the map shown in FIG. 13 (step S122 in FIG. 6), and the accelerator pedal is continuously released and the brake is depressed. Therefore, in step S148 of FIG. 7, the upshift correction amount DDSRUP, which is a decrement value of the correction target input rotation speed DSRENBR, is added, and the control target input rotation speed DSR is added.
REV is reduced every predetermined time (5 msec), and if the vehicle acceleration is in the deceleration region B or C shown in FIG. 14, the speed at which the engine braking force is weakened increases according to the magnitude of the deceleration.

Here, the correction amount of the upshift correction amount DDSRUP for increasing the target input rotational speed of the continuously variable transmission 2 in order to reduce the engine braking force is shown in FIG.
As shown in FIG. 4, the larger the deceleration generated in the vehicle when the predetermined value is exceeded, the larger the correction amount D per unit time.
DSRUP is set to be large, and even if the deceleration generated in the vehicle changes abruptly, only the correction amount DDSRUP per unit time changes, and the control target input rotation speed DSRREV is the same as that of the conventional example. As shown in FIG. 15, the engine braking force does not change abruptly and stepwise, and the engine braking force can be changed smoothly while responding to the change in acceleration.

That is, when the vehicle is coasting on a downhill where the slope is not constant and the accelerator pedal is released, the deceleration generated in the vehicle changes from a downhill to an uphill, and the weight gradient resistance in the above-described conventional example becomes large. If it is equal to or greater than the target input rotational speed, the target input rotational speed is still largely corrected, whereas in the present invention, if the deceleration occurring in the vehicle exceeds a predetermined value, the correction amount per unit time of the target input rotational speed per unit time Is increased, so that the upshift correction amount D per unit time can be obtained even when the deceleration suddenly increases.
The control target input rotational speed DSRREV is corrected to a small value per unit time by the DSRUP, so that the vehicle can be smoothly controlled without a sudden deceleration of the vehicle. To prevent the sudden change in the engine brake and the gradual decrease in deceleration that the driver does not intend, thereby preventing the driver from unintentionally feeling uncomfortable or discomfort. This makes it possible to improve the riding comfort and the drivability.

In a deceleration state in which the deceleration is very small but not zero, as in the deceleration area A of FIG. 14, the upshift correction amount DDSRUP becomes zero or almost zero. When the vehicle turns from a downhill to an uphill, the driver does not feel a sense of discomfort due to the slight deceleration caused by the uphill, and the target input rotation speed is reduced in this deceleration area A according to the deceleration. In this case (broken line in FIG. 14), frequent changes in the engine speed are caused. In the present invention, however, the frequent fluctuations in the engine speed in the deceleration region A cause uncomfortable feeling and unnaturalness due to the change in the noise and the deceleration. It prevents pleasure. As described above, in the deceleration region A in which the deceleration is equal to or more than the predetermined value so that the driver does not feel uncomfortable even if the vehicle is gradually decelerated, the upshift correction amount DDS
By setting RUP to 0 or almost 0 so that the engine brake is not effective, more comfortable driving and riding comfort can be realized in coasting running from downhill to uphill. You can do it.

Further, when the vehicle is coasting on a slope where the slope changes from a downhill to an uphill, it is desired to weaken the engine braking force slightly earlier than when the vehicle turns to a gentle uphill. A sudden increase in the engine braking force in a stepwise manner as in the conventional example gives the driver an uncomfortable feeling.

On the other hand, in this embodiment, as the deceleration is larger as in the deceleration region B of FIG. 14, the absolute value of the upshift correction amount DDSRUP per unit time is set to be larger, so that the vehicle is reduced. As the speed increases, the speed at which the engine braking force is weakened can be increased, and the engine braking force can be changed smoothly while responding to changes in the gradient, and deceleration according to the driver's expectations , And driving performance and riding comfort can be greatly improved.

In the deceleration region C where the deceleration exceeds the second predetermined value, even if the downhill slope before the uphill slope is extremely large, the deceleration is proportional to the deceleration as shown by the broken line in the figure. And reduce the correction amount of the target input speed,
While the engine braking force may suddenly decrease and the vehicle may feel as though it is accelerating and rushing, the upshift correction amount DDSRUP in this region C is almost constant or gradually decreases from the deceleration region B. The deceleration can be changed continuously while preventing the sense of rushing of the vehicle when turning from a steep downhill to an uphill, and the speed at which the deceleration is weakened is almost constant Or a gradual increase, so that the driver does not feel uncomfortable or uncomfortable, and the drivability and riding comfort of the vehicle equipped with the continuously variable transmission can be greatly improved. It is.

The deceleration performed by the upshift correction amount DDSRUP set as described above does not converge to acceleration = 0 but is performed from the acceleration region shown in FIG. 12 to the constant velocity region. The constant velocity range is set by an experiment or the like by the present applicant.

Here, the outline of the acceleration / deceleration determination map shown in FIG. 12 will be described. The deceleration expected when the driver releases the accelerator pedal is almost independent of the vehicle speed VSP as shown in FIG. About 0.06G (acceleration =-
0.06 G) was found to be around 0.06 G) through experiments conducted by the present applicant. However, if the deceleration is simply set to ≒ 0.06 G, the driver's sensible acceleration may give an uncomfortable feeling because the engine braking force is too strong in a low vehicle speed range, while the engine braking force may be insufficient in a high vehicle speed range. .

Therefore, the target deceleration is reduced in accordance with the driver's perceived acceleration in the low vehicle speed range from 0.06 G, while the deceleration is increased in the high vehicle speed range to secure the engine braking force. In addition, the engine braking force is continuously changed so that the vehicle acceleration when the accelerator pedal is released is in a constant speed range which is a predetermined acceleration range. In FIG. 12, an area above the constant velocity area is an acceleration area where the driver experiences the acceleration of the vehicle, and a part below the constant velocity area is set as a deceleration area where the driver experiences the deceleration of the vehicle. And the boundary between the acceleration region and the deceleration region are set as the threshold values VSPOVLM and VSPUDLM as described above.
In this embodiment, these threshold values VSPOVLM
And VSPUDLM are mapped, but may be treated as functions.

In this manner, when the vehicle is coasting on a slope having unevenness on the road surface or a slight change in the gradient, the accelerator pedal is released and the continuously variable transmission 2 is driven in accordance with the magnitude of the deceleration generated in the vehicle. It is possible to continuously control the engine braking force by gradually changing the input rotation speed even on a slope where the speed at which the input rotation speed is reduced is changed continuously and the deceleration changes rapidly. 15, even when the gradient is reversed from a downhill to an uphill as shown in FIG. 15, by preventing the rapid deceleration as in the conventional example and smoothly reducing the engine braking force, the driver's Since it is possible to perform deceleration according to expectations, it is possible to eliminate discomfort and discomfort as in the conventional example, and it is possible to greatly improve the drivability and riding comfort of a vehicle equipped with a continuously variable transmission. is there.

[0105]

As described above, in the first invention, the gradient changes from downhill to uphill during coasting, and the deceleration is reduced.
When the speed exceeds a predetermined constant speed range , the engine braking force can be continuously and smoothly changed according to the driver's expectation while suppressing a rapid change in deceleration. This eliminates any discomfort or discomfort caused by the rapid increase in deceleration, and enables smooth coasting such as turning from a downhill to an uphill, making it possible to drive and ride a vehicle equipped with a continuously variable transmission. The comfort can be greatly improved.

According to the second aspect of the present invention, the gradient is increased from a downhill to an uphill with the accelerator pedal released in order to increase the absolute value of the correction amount per unit time in accordance with the magnitude of the deceleration. In such a case, the corrected target input speed is rapidly reduced, the speed at which the engine braking force is weakened can be smoothly increased, and the engine is continuously operated without giving the driver a sense of incongruity. It is possible to change the braking force, realize smooth coasting while obtaining deceleration according to the driver's expectations, and drastically improve the driving performance and riding comfort of vehicles equipped with a continuously variable transmission. It can be improved.

In the third invention, the correction amount per unit time is set to zero or almost zero when the deceleration is equal to or less than a predetermined value. Decelerates gently with little decrease, but when coasting on a gentle uphill where the deceleration is equal to or less than the predetermined value with the accelerator pedal released, the driver does not like the fluctuation of the engine brake, The target input rotation speed does not frequently fluctuate in accordance with the change in the gradient as in the conventional example, and unnecessary fluctuation of the engine rotation speed and increase of the engine brake which the driver does not expect are prevented, so that The inertia traveling can be realized, and the drivability of the vehicle including the continuously variable transmission can be further improved.

Further, in the fourth invention, when the deceleration exceeds the second threshold value, the correction amount per unit time for decreasing the target input rotation speed becomes substantially constant, and the slope of the slope during coasting is reduced. When turning from a large downhill to an uphill or a flat road, it is possible to prevent a sense of speed increase of the vehicle due to a sudden decrease in the target input speed, and to provide an engine that meets the driver's expectations without giving a sense of discomfort or discomfort The braking force can be continuously obtained, and the drivability of the vehicle including the continuously variable transmission can be further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a shift control device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a main routine of control performed by a shift control controller.

FIG. 3 is a flowchart showing an outline of a subroutine of engine brake correction control.

FIG. 4 is a flowchart showing details of engine brake correction control and showing a search process of a correction control range and an acceleration / deceleration determination threshold value.

FIG. 5 is a flowchart showing acceleration calculation and acceleration / deceleration determination processing.

FIG. 6 is a flowchart showing a process of searching for a correction amount of a target input rotational speed and dividing a case according to an operating state.

FIG. 7 is a flowchart showing the setting of a corrected target input rotation speed DSRENBR when the accelerator pedal is continuously released.

FIG. 8 is a flowchart showing the setting of a corrected target input rotation speed DSRENBR when the accelerator pedal is depressed.

FIG. 9 is a flowchart showing the setting of a corrected target input rotation speed DSRENBR at the moment when the accelerator pedal is released.

FIG. 10 is a flowchart showing a rotation limit check process.

FIG. 11 shows the throttle opening TVO as a parameter.
4 is a shift map showing a control target input rotational speed DSRREV according to a vehicle speed VSP.

FIG. 12 is a map showing a relationship between a vehicle speed VSP and a threshold value of a vehicle acceleration.

FIG. 13 shows a downshift correction amount DDSRDN and an upshift correction amount DD per unit time according to vehicle acceleration.
Map showing SRUP.

FIG. 14 is a graph showing the setting of the upshift correction amount DDSRUP, showing the relationship between the correction amount per unit time and acceleration.

FIG. 15 is an explanatory diagram showing a state of coasting when the vehicle turns from a downhill to an uphill according to the present invention.

FIG. 16 is a graph showing the relationship between the deceleration expected by the driver during coasting and the vehicle speed VSP.

FIG. 17 is an explanatory diagram showing a state of coasting when a conventional example turns from a downhill to an uphill.

FIG. 18 is a diagram corresponding to claims of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 engine 2 continuously variable transmission 3 drive shaft 4 fuel injection valve 5 gear ratio changing means 6 engine control controller 7 shift control controller 8 vehicle speed sensor 9 throttle opening sensor 10 engine rotation sensor 12 brake switch 14 vehicle acceleration sensor 15 idle switch 50 Shift control means 51 deceleration detection means 52 opening degree detection means 53 deceleration comparison means 54 correction amount calculation means 55 correction target input rotation speed setting means

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI F16H 59:48 F16H 59:48 (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 59/00-61/12 F16H 61/16-61/24 F16H 63/40-63/48

Claims (4)

(57) [Claims] A speed ratio changing means for changing a speed ratio of the continuously variable transmission; a target input speed of an input shaft of the continuously variable transmission calculated according to a driving state of the vehicle; A speed change control device for controlling the speed ratio changing means so that the speed is equal to a target input rotation speed. A deceleration detection means for detecting a deceleration of a vehicle, an accelerator pedal Opening degree detecting means for detecting the operation state of, when the opening degree detecting means detects the release of the accelerator pedal, deceleration comparing means for comparing the detected deceleration with a preset constant velocity region , Correction amount calculating means for calculating a correction amount per predetermined unit time for correcting the target input rotational speed to be small when the deceleration exceeds a preset constant speed region , in accordance with a detected value of the deceleration; And this correction amount A step of setting a corrected target input rotational speed to be subtracted from a target input rotational speed, wherein the shift control unit controls the speed ratio changing unit based on the corrected target input rotational speed. Gear shift control device. 2. The continuously variable transmission according to claim 1, wherein said correction amount calculating means increases the absolute value of the correction amount per predetermined unit time according to the magnitude of deceleration. Transmission control device. 3. The correction amount calculation means according to claim 1, wherein the correction amount per predetermined unit time is set to zero or substantially zero when the deceleration is equal to or less than a predetermined value. Transmission control device for continuously variable transmission. 4. The apparatus according to claim 1, wherein the correction amount calculating means is configured to determine the deceleration and the second deceleration.
And when the deceleration exceeds the second threshold, the correction amount per predetermined unit time is set substantially constant regardless of the magnitude of the deceleration. The shift control device for a continuously variable transmission according to claim 1.