JPH09112680A - Transmission control device for continuously variable transmission - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To control an engine brake during coasting so as to obtain a feeling of deceleration according to a driver's expectation according to a vehicle speed. SOLUTION: The gear change control means 50 for controlling the gear ratio changing means 5 so that the target input speed and the input shaft speed corresponding to the operating state match, means for detecting acceleration 51, and the operation status of the accelerator pedal. An opening degree detection means 52 for detecting,
A means 53 for comparing the acceleration with a predetermined threshold value when detecting the release of the accelerator pedal, and an engine brake increase correction amount calculating means for greatly correcting the target input speed when the acceleration exceeds the threshold value. 54, a correction target input rotation speed setting means 55 for adding a correction amount to the target input rotation speed,
Threshold changing means 5 for decreasing the threshold according to the vehicle speed
6, the shift control means 50 controls the gear ratio changing means 5 based on the corrected target input rotation speed.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as a continuously variable transmission used in a vehicle such as an automobile, a V-belt type or a toroidal type (friction wheel type) has been known, and a shift control device for such a continuously variable transmission. Then, the target value of the engine speed input to the continuously variable transmission is set on the basis of the engine throttle opening (or accelerator opening, the same applies below) and the vehicle speed, and the gear ratio corresponding to this target engine speed is set. It is known to control continuously.

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

Japanese Patent Application Laid-Open No. 6-819 discloses a method for reducing frequent braking operations during coasting on such a downhill.
No. 32 and the like are known, in which the lower limit of the target input speed of the continuously variable transmission is set to a large value in accordance with the increase in the absolute value of the weight gradient resistance of the vehicle, and the engine braking is actively performed. It is intended to operate.

[0005]

However, in the above-described conventional shift control device, the lower limit of the target input speed is set large in accordance with the increase in the absolute value of the weight gradient resistance of the vehicle, so that the gradient is constant. When coasting on a downhill with the accelerator pedal released, the target input speed changes frequently in response to changes in the gradient, and shocks due to sudden changes in acceleration and engine speed changes constantly, which may cause the driver to There is a problem of giving offensiveness to. Also,
In the state where the accelerator pedal is released, the feeling of deceleration due to engine braking expected by the driver changes according to the vehicle speed, but in the above-mentioned conventional example, even when the same downward gradient is applied, the same vehicle weight is used, and the vehicle speed is different. Since the target input speed does not change and the deceleration due to engine braking does not change according to the vehicle speed, the deceleration is insufficient for the driver in the high vehicle speed range where large deceleration is expected by releasing the accelerator pedal. On the other hand, there is a problem that the driver feels uncomfortable and does not expect to decelerate even if the accelerator pedal is released. .

Therefore, the present invention has been made in view of the above problems, and changes the deceleration due to the engine brake during coasting with the accelerator pedal released according to the vehicle speed to obtain the deceleration feeling expected by the driver. Aim to get.

[0007]

The first invention, as shown in FIG. 17, is a gear ratio changing means 5 for changing the gear ratio of a continuously variable transmission 2, and a continuously variable gear shift according to the operating condition of the vehicle. A continuously variable transmission including a speed change control means 50 for calculating a target input speed of the input shaft of the machine 2 and controlling the speed ratio changing means 5 so that the input shaft speed coincides with the target input speed. In a shift control device for a machine, an acceleration detecting means 51 for detecting an acceleration of a vehicle, an opening degree detecting means 52 for detecting an operation state of an accelerator pedal, and an opening degree detecting means 52 for detecting a release of the accelerator pedal. , Acceleration comparing means 53 for comparing the detected acceleration with a predetermined threshold value
An engine brake increase correction amount calculation means 54 for correcting the target input speed to increase when the acceleration exceeds a threshold value, and a corrected target input speed for adding the correction amount to the target input speed. The gear shift control unit 50 includes a number setting unit 55 and a threshold value changing unit 56 that decreases the threshold value according to an increase in vehicle speed. Change means 5
Control.

In a second aspect based on the first aspect, the threshold value changing means sets the threshold value to a predetermined value larger than 0 in a low vehicle speed range where the vehicle speed is equal to or lower than the first predetermined value. On the other hand, in the high vehicle speed range where the vehicle speed is equal to or higher than the second predetermined value, the threshold value is set to a predetermined value smaller than 0.

The third aspect of the present invention, as shown in FIG. 18, is a gear ratio changing means 5 for changing the gear ratio of the continuously variable transmission 2.
And a target input speed of the input shaft of the continuously variable transmission 2 is calculated according to the operating state of the vehicle, and the speed ratio changing means 5 is arranged so that the input shaft speed matches the target input speed.
In a shift control device for a continuously variable transmission, which includes a shift control unit 50 for controlling an acceleration, an acceleration detection unit 51 for detecting a vehicle acceleration, an opening degree detection unit 52 for detecting an operation state of an accelerator pedal, and the opening control unit. When the degree detecting means 52 detects the release of the accelerator pedal, the deceleration comparing means 53 'for comparing the detected acceleration with a predetermined threshold value, and the target input when the acceleration is smaller than the threshold value. Engine brake decrease correction amount calculation means 54 'for correcting the rotation speed to be small, correction target input rotation speed setting means 55 for subtracting the correction amount from the target input rotation speed, and the threshold value for increasing the vehicle speed. The gear shift control means 50 includes a threshold value changing means 56 for decreasing the gear ratio according to the corrected target input speed.
Control.

In a fourth aspect based on the third aspect, the threshold value changing means sets the threshold value to a value smaller than 0 and close to 0 in a low vehicle speed range where the vehicle speed is equal to or lower than a predetermined value. Set to the value.

[0011]

Therefore, in the first aspect of the invention, the shift control means controls the gear ratio changing means so that the input shaft speed of the continuously variable transmission matches the target input speed in accordance with the operating condition of the vehicle. However, when the driver releases the accelerator pedal and the acceleration of the vehicle exceeds a predetermined threshold value, the target input speed is corrected to increase and the engine brake is strengthened. Since the threshold value for determining is decreased as the vehicle speed increases, engine braking does not increase in the low vehicle speed range even in the slightly accelerated state, while it increases in the high vehicle speed range if the vehicle is in the accelerated state. The engine brake can be strengthened, and a feeling of deceleration according to the driver's expectation, which differs depending on the vehicle speed, can be obtained during coasting.

According to the second aspect of the invention, the threshold value for determining the acceleration is greater than 0 in the low vehicle speed range where the vehicle speed is equal to or lower than the first predetermined value, and is greater than 0 in the high vehicle speed range where the vehicle speed is equal to or higher than the second predetermined value. Since it is set to a small value, it is possible to forcibly coast the engine by prohibiting increasing the engine brake even in the low vehicle speed range even if the vehicle is slightly accelerating, while in the high vehicle speed range it is possible to strengthen the engine brake when entering the coasting mode. Thus, when coasting, it is possible to obtain a feeling of deceleration according to the driver's expectation that differs depending on the vehicle speed.

According to a third aspect of the present invention, the shift control means controls the gear ratio changing means so that the input shaft speed of the continuously variable transmission matches the target input speed in accordance with the operating condition of the vehicle. However, when the driver releases the accelerator pedal and the vehicle acceleration is smaller than a predetermined threshold value, the target input speed is corrected to be smaller and the engine brake is weakened. Since the threshold value to be determined decreases as the vehicle speed increases, in the low vehicle speed range, when the vehicle decelerates, the engine brake is quickly weakened to promote coasting, while in the high vehicle speed range, the deceleration increases slightly ( Even if the acceleration is reduced), the engine brake is not weakened, and even if the gradient changes during coasting on a downhill or the like, excessive fluctuation of the engine braking force is prevented, and it varies depending on the vehicle speed during coasting. driver It is possible to obtain a slowdown in accordance with the expectations.

According to the fourth aspect of the invention, the threshold value for determining the acceleration is set to a predetermined value near 0, which is smaller than 0 in the low vehicle speed range where the vehicle speed is equal to or lower than the predetermined value. When the vehicle is in a decelerating state for a short time, the engine brake can be weakened to promote coasting, preventing frequent deceleration during coasting in the low vehicle speed range and meeting the driver's expectations in the low vehicle speed range. You can get a feeling of deceleration.

[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 gear ratio according to the operating state of the vehicle by the gear ratio changing means 5 controlled by the gear shift controller 7. The continuously variable transmission 2 is, for example, a V-belt type or toroidal type. It is composed of expressions, etc.

The shift control controller 7 is mainly composed of a microprocessor, etc., 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 drive wheel rotation sensor 11, a braking device. The brake switch 12 for detecting the operating state of the vehicle, the vehicle acceleration sensor 14 for detecting the longitudinal acceleration G of the vehicle, the idle switch 15 for detecting the released state of the accelerator pedal, and the rotational speed No of the output shaft of the continuously variable transmission 2. As a means for detecting the output shaft rotation sensor 13 and the input shaft rotation speed Ni of the continuously variable transmission 2, driving is performed based on a signal indicating a driving state of the vehicle input from the engine rotation sensor 10 that detects the engine rotation speed Ne. Control target input speed D according to the state
In addition to calculating SRREV, the gear ratio changing means 5 composed of an actuator and the like is instructed to the target gear ratio DSRRTO so that the input shaft speed = the engine speed Ne matches the target input speed, and an output shaft (not shown) is output. The driving force from the engine 1 is transmitted to the drive shaft 3 coupled with the.

In the present embodiment, the case where the engine 1 and the input shaft of the continuously variable transmission 2 are directly connected is shown. The engine speed Ne = the input shaft speed Ni, but the engine 1 and the continuously variable transmission are When a reduction mechanism, a torque converter, or the like is provided between the transmission 2 and the input shaft, an input shaft rotation sensor may be provided and the detected value may be the input shaft rotation speed Ni.

The shift control controller 7 is also connected to the engine control controller 6 which controls the engine 1 in accordance with the operating state of the vehicle, and sends a shift ratio control signal and the like from the shift control controller 7 to the engine control controller 6. On the other hand, various operation information such as fuel injection cut is sent from the engine controller 6 and the engine 1
The shift control controller 7 constitutes an integrated control system which is controlled synchronously.

The engine controller 6 controls the supercharging pressure in addition to the fuel injection control from the fuel injection nozzle 4 and the ignition timing control according to the operating state of the vehicle. Control is 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, while control such as fuel injection recovery is performed when the throttle is fully closed. In this embodiment, the case where the engine 1 is configured by a spark ignition type internal combustion engine is shown.

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

Here, in FIG. 2, every predetermined time, for example, 5 ms.
An outline of the main routine of the shift control executed for each ec is shown, and FIG. 3 and subsequent figures show a subroutine for performing engine brake correction at the time of traveling on a downhill. After explaining the outline of the shift control, the engine brake is explained. The correction control 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. In step S2, the throttle opening TVO and the vehicle speed V read in step S1 are read.
Based on SP, the control target input speed DSRREV, which is the target value of the input shaft speed Ni (= engine speed Ne) of the continuously variable transmission 2, is calculated from the shift map shown in FIG.

In step S3, step S1 described later is executed.
From 0 onward, according to the longitudinal acceleration G applied to the vehicle, the control target input speed DSRRE during engine braking is activated.
Correct V.

Then, in step S4, the control target input speed DSRREV after correction by engine braking is performed.
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 gear ratio changing means 5 of the continuously variable transmission 2 to make the continuously variable transmission 2
Control the gear ratio of.

[2. Engine Brake Correction Control] The flowchart of FIG. 3 shows an outline of a subroutine of the engine brake correction control performed in step S3, and the details of this subroutine are configured as in the flowcharts of FIGS. 4 to 10 described later. First, the outline of the engine brake correction control will be described.

In step S10, the control target input speed DSRRE obtained in step S2 of the main routine is determined.
According to V, the input shaft speed Ni of the continuously variable transmission 2 (hereinafter,
The correction control range in which the input shaft speed is simply changed is determined.

In step S11, in order to determine whether the engine brake needs to be further strengthened or weakened compared to the present, the longitudinal acceleration of the vehicle (hereinafter,
Simply calculate the threshold value of acceleration or deceleration).

Then, 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 further strengthen or weaken the engine brake. Is determined based on the operation status of the accelerator pedal.

In step S13, the correction amount of the target input speed per unit time, which is the 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
Based on the correction amount obtained in step 13, the correction target input speed DS for generating the engine braking force according to the acceleration
RENBR is calculated, and in step S15, the corrected target input rotation speed DSRENBR is set 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 by the control target input speed DSRREV to which the engine brake correction is added.

Details of the engine brake correction control will be described below with reference to the flow charts of FIGS. 4 to 10.

[2.1 Determination of Control Target Input Rotational Speed Correction Range 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 are shown. Corresponds to steps S10 and S11 of the outline shown in FIG.

In step S101, based on the vehicle speed VSP read in step S1, the upper limit input speed DSR which is the upper limit value of the correction control range from the map shown in FIG. 11 is used.
Calculate HLMT. Note that the map shown in FIG. 11 is one in which the input rotation speed according to the vehicle speed VSP is preset 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 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, it is determined in FIG. 1 whether the engine brake needs to be further strengthened or weakened compared to the present.
Based on the map shown in FIG. 2, the acceleration-side threshold value VSPOVLM and the deceleration-side threshold value VSPUDL are set.
M is calculated according to the vehicle speed VSP.

The map shown in FIG. 12 is used when the accelerator pedal is released (idle switch 1
5 = ON), which is set in advance according to the sensation of deceleration that the driver expects, and is set mainly in the constant velocity range having a predetermined acceleration range that changes according to the speed. However, this constant velocity region does not indicate a physical constant velocity (acceleration = 0 G), but is a region where the driver feels that the vehicle is traveling at a substantially constant velocity when the accelerator pedal is released. Is the acceleration region where the driver feels the acceleration of the vehicle, and below the constant velocity region is the deceleration region where the driver feels the vehicle deceleration, and the boundary between the constant velocity region and the acceleration region is the acceleration side threshold. V
In SPOBLM, the boundary between the constant speed region and the deceleration region is the deceleration side threshold value VSPUDLM.

An example in which the idle switch 15 is used as the opening detection means for detecting the operation state of the accelerator pedal is shown. However, in a spark ignition type internal combustion engine such as a gasoline vehicle or a gas fuel vehicle, it is based on the throttle opening TVO. Thus, the released state of the accelerator pedal may be detected.

Thus, 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 respectively, the process proceeds to the acceleration / deceleration determination process of step S110 shown in FIG.

[2.2 Acceleration / Deceleration Judgment Processing] In steps S110 to S118 of FIG. 5, it is judged which area the current vehicle acceleration is in the map of FIG. 12, and the flowchart of FIG. Corresponds to step S12.

First, in step S111, it is determined whether the vehicle speed VSP read in step S1 is within a predetermined low speed range, for example, 10 km / h or less. If the vehicle speed VSP is within the predetermined low speed range, the process proceeds to step S118. Acceleration TKRAM
While S6 is set to 0, otherwise, the process proceeds to step S112.

In step S112, the vehicle acceleration T is calculated from the difference between the current vehicle speed VSP and the vehicle speed VSP _-5 of a predetermined time before, for example, 5 cycles before (50 msec before).
Find KRAMS6. Incidentally, as the acceleration detecting means,
Although the case where the differential value of the vehicle speed VSP is used is shown, the differential value of the detected value G of the vehicle acceleration sensor 14 or the detected value of the drive 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.
When AMS6 is larger than the threshold value VSPOVLM, it is determined that the current vehicle acceleration TKRAMS6 is in the acceleration range in which the engine brake needs to be increased in the map shown in FIG. 12, and the process proceeds to step S117,
If 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.

Step S114 is 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 process proceeds to step S116 to set 1 to the deceleration flag VSPMNS, and otherwise. Is determined to be in the constant velocity range of FIG. 12, the process proceeds to step S115, and the constant velocity flag VSPEQS is set to 1. In step S118, the vehicle acceleration TKRA
Even in the low speed range where MS6 = 0 is set, step S11
The constant velocity flag is set to 1 at 5.

Thus, the threshold values VSPOVLM, VS
By comparing the PUDLM and the vehicle acceleration TKRAMS6, which region of the map in FIG. 12 the vehicle acceleration is in is discriminated by the acceleration, deceleration, and constant velocity flags. After that, the process proceeds to step S120 in FIG. The correction amount of the target input speed is searched and the mode is classified according to the accelerator pedal operation.

[2.3 Target Input Rotational Speed Correction Amount Setting and Mode Classification According to Driving Operation] Step S120 to FIG. 6
In S131, after setting the correction amount of the target input rotational speed according to the vehicle acceleration TKRAMS6, the operation situation of the accelerator pedal, that is, the case classification according to the driver's intention is performed, and step S13 of the flowchart of FIG. 3 is performed. 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 DDSRNN or the upshift correction amount DDSRUP from the map shown in FIG. 2 according to the magnitude and sign of the vehicle acceleration TKRAMS6.

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

The map of FIG. 13 shows the speed at which the engine braking force is changed according to the magnitude and the positive / negative of the driver's sensory acceleration, based on the experiment of the applicant of the present application, and the upshift correction amount. It is preset as the DDSRUP or the downshift correction amount DDSRDN, and is stored in a storage means such as a ROM (not shown) of the shift control controller 7.

Next, in steps S123 to S131,
The driver's intention of acceleration / deceleration is estimated from the change of the previous value and the current value of the operation state of the accelerator pedal to classify the cases.

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

In step S124, whether the flag IDLE indicating the current status of the idle switch 15 is 0,
In other words, determine whether the accelerator pedal is depressed,
If it is stepped on, it proceeds to step S126, and if it is released (IDLE = 1), it proceeds to step S127.

In step S126, the accelerator pedal is continuously depressed both last time and now, and the idle switch 15 is in the OFF or OFF state, and the process proceeds to step S150, which will be described later.

On the other hand, if it is determined in step S124 that the accelerator pedal is currently released, the accelerator pedal depression state has changed from the previous value. Therefore, in step S127, the current state of the idle switch 15 is OLDIDLE = The value is updated as 1, and in step S128, it is determined that the idle switch 15 is turned from OFF to ON and the accelerator pedal that was being depressed is released, and the process proceeds to step S160.

On the other hand, the last idle switch 15 is turned on.
Also in step S125, which is the same as 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 so, the process proceeds to step S130. If it is released (IDLE = 1), the process proceeds to step S129.

In step S129, since the accelerator pedal is continuously released, the previous idle switch flag OLDIDLE is not changed and the step S1 is performed.
Continue to release 40 and proceed to processing.

On the other hand, if it is determined in step S125 that the accelerator pedal is currently depressed, it means that 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 to OLDIDLE = 0, and in step S131
Then, the idle switch 15 is switched from ON to OFF,
It is determined that the released accelerator pedal is depressed, and the process proceeds to step S150.

In this way, by comparing the previous value OLDIDLE of the idle switch 15 with the current value IDLE, the change in the depression state of the accelerator pedal is checked in step S.
The target input speed is corrected in each of the three cases of 140, 150, and 160, and these steps S140
The subsequent steps correspond to step S14 in FIG.

Although the operation state of the accelerator pedal is detected by the idle switch 15 in the above, it may be performed based on the detected 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 has the previous value,
The correction process of the target input speed when the accelerator pedal is continuously released, in which both the current values are ON, is shown.
Then, it is determined whether or not the acceleration flag VSPPLS set in steps S110 to 118 is 1, and if it is 1, the current vehicle acceleration is in the acceleration range of the map of FIG. , 0, the process proceeds to step S142.

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

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

Then, in step S144, the 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 process proceeds to step S142 to determine whether the correction control is being performed. If the correction control is being performed, step S1
While proceeding to 45, it is judged whether or not the vehicle is in the deceleration range, while when the correction control is not carried out, the routine proceeds to step S146.

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

In step S145, it is determined whether or not the deceleration flag VSPMNS is set in step S116 of FIG. 5, and if the current vehicle acceleration is in the deceleration range of the map shown in FIG. 12, the process proceeds to step S147, while If not, the process proceeds to step S170.

In step S147, the output signal BRK of the brake switch 12 is checked to see if the brake is depressed.
Determined by If the brake is not pressed (BR
(K = 0), the process proceeds to step S148 to perform correction processing in the deceleration range while the brake is being pressed (BR
For K = 1), even in the deceleration region where the engine brake needs to be weakened, the deceleration region is corrected in order to prohibit the correction of the target input speed to be small and give priority to the braking operation of the driver. Instead, it proceeds to step 170.

In step S148, 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 upshift correction amount DDSRUP obtained in step S122 of FIG. 6 is set to the corrected target input rotation speed DSREN.
The target input rotation speed is gradually reduced by subtracting from the previous value of BR (the upshift correction amount DDSRUUP becomes a negative value, and therefore the correction target input rotation speed DSRENBR is subtracted by adding this to the previous value. ).

DSRENBR = DSRENBR ₋₁ + DDSRUP Then, the process proceeds to the rotation check in step S170.

[2.5 When the accelerator pedal is stepped on] Steps S150 to 155 in FIG. 8 are target input rotations 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 accelerator pedal is continuously depressed. The number correction process is shown.

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

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

In step S154, a value obtained by subtracting a predetermined value from the previous correction target input rotation speed DSRENBR _-1 and slightly lowering the target input rotation speed is set as the correction target input rotation speed DSRENBR for this time as follows. , DSRENBR = DSRENBR ₋₁ −1 In this case, the corrected target input speed DSRENBR is set to 1rp.
The correction target input rotation speed DSRENBR is gradually approached to the control target input rotation speed DSRREV by decreasing by m, and then the processing without rotation limiter in step S171 is performed.

On the other hand, in step S153, the correction control in progress flag N is set because the correction control of the engine brake is ended.
After resetting OWCNT to 0, step S155
To the correction target input speed DSRENBR in step S
The control target input speed DSRREV obtained in 2 is stored,
Similar to the above, the process proceeds to step S171.

[2.6 When the accelerator pedal is released] Steps S160 to 164 in FIG. 9 are 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. A correction process is shown.

In step S161, the corrected target input rotational speed DSRENBR _{-1 of the} previous process and the upper limit input rotational speed DS of the correction control range obtained in step S101 of FIG.
Comparing with RHLMT, the previous correction target input speed D
When SRENBR _-1 exceeds the upper limit input speed DSRHLMT, the process proceeds to step S162, while when SRENBR _-1 is equal to or lower than the upper limit input speed DSRHLMT, step S163.
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 rotation check processing in step S170 is performed.

On the other hand, if it is less than or equal to the upper limit input rotation speed DSRHLMT, it is determined in step S163 whether the correction control is being performed, and if it is not, the step S16 is performed.
4, the control target input speed DSRREV is set in the correction target input speed DSRENBR, and step S17 is performed.
Although the process proceeds to 0, if the correction control is being performed, step S1 is directly performed.
Proceed to the process of 70.

[2.7 New Control Target Input Rotational Speed DSRR
EV Setting] In the above 2.4 to 2.6, the accelerator pedal operation status is divided into three cases, and the correction target input rotation speed DSRENBR is set respectively, and then the process proceeds to step S170 or S171, and the engine is operated. The control target input speed DSRREV after the brake correction control is set in step S170 and subsequent steps in FIG.
Steps after 170 correspond to step S15 in FIG.

When the routine proceeds to the rotation check processing in step S170, it is determined in step S172 whether the corrected target input rotation speed DSRENBR is less than or equal to the lower limit input rotation speed DSRLLMT of the correction control range obtained in step S102 of FIG. If it is determined that the corrected target input rotation speed DSRENBR is less than or equal to the lower limit input rotation speed, the process proceeds to step S173. If not, the process proceeds to step S175.

In step S173, the lower limit input rotation speed DSRLLMT of the correction control range is newly set as the correction target input rotation speed DSRENBR, and then the correction control in-progress flag NOWCNT is reset to 0 in order to end the correction control, and then in step S177. Go to.

On the other hand, it is determined in step S172 that the corrected target input speed DSRENBR is 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 is obtained.
It is determined whether SRHLMT is exceeded, and if it exceeds, a new correction target input rotation speed D is obtained in step S176.
Upper limit input speed DS of correction control range as SRENBR
After setting RHLMT, the process proceeds to step S177.

From the above process [2.5] to step S1.
When the process proceeds to the process without the rotation limiter in 71, the process directly proceeds to step S177.

In step S177, the corrected target input rotational speed DSR set by the engine brake correction control is set.
ENBR is set as a new control target input speed DSRREV, and the process returns to step S4 in FIG. In this way, the gear ratio changing means 5 of the continuously variable transmission 2 is driven so that the target gear ratio DSRTO corresponding to the corrected target input rotation speed DSRENBR after the engine brake correction control is performed, and the vehicle acceleration is as shown in FIG. It converges to the constant speed range shown in the map and is continuously controlled toward the engine braking force according to the vehicle speed VSP expected by the driver.

[3. Setting of acceleration / deceleration determination map according to vehicle speed VSP] Here, control target input speed DSRREV
Is a case where the engine braking force is continuously controlled at a speed according to the map of FIG. 13 when the vehicle deviates from the constant speed range shown in FIG. 12 during inertial running with the accelerator pedal released. The acceleration / deceleration determination map of FIG. 12 that causes the acceleration of the vehicle to converge to a predetermined range by the engine brake is set based on an experiment by the applicant of the present application.
This map will be described in detail.

According to the experiment by the applicant of the present application, the deceleration expected when the driver releases the accelerator pedal is about 0. 0, which is almost independent of the vehicle speed VSP in a predetermined vehicle speed range, as shown in FIG. It was found to be around 06G (acceleration = -0.06G).

Therefore, according to the present invention, as shown in FIG. 15, the deceleration due to engine braking is 0.06 as the predetermined value expected by the driver during coasting with the accelerator pedal released.
The target input speed of the continuously variable transmission 2 is controlled so as to converge to a target acceleration range ΔG having a predetermined width around G, and if the acceleration generated in the vehicle is smaller than the target acceleration range (Fig. At the midpoint G ₁ ), the target input speed is corrected to a small value to weaken the engine braking force, while if the acceleration generated in the vehicle is larger than the target acceleration range (point G _{2 in the} figure), the target input speed is corrected to a large value. To strengthen the engine brake.

By the way, the target acceleration range ΔG is set to the vehicle speed VS.
If the acceleration is set to around -0.06 G regardless of P, the engine braking force will be too strong in the low vehicle speed range (about 20 km / h), especially in the conventional automatic transmission using a torque converter. A familiar driver is accustomed to the creep phenomenon due to the torque converter, so in such a low vehicle speed range, the driver prefers an idle state in which deceleration hardly occurs, and the above deceleration causes discomfort. It turns out that there are cases.

On the other hand, in coasting with the accelerator pedal released in the high vehicle speed range (100 km / h or more), the driver expects a larger deceleration than in the vehicle speed range on the general road. It has been found that there is a case where the driver may feel uncomfortable due to insufficient braking force. In particular, even a driver who is accustomed to the conventional torque converter type automatic transmission may feel dissatisfied with the engine braking force generated at the shift position on the high speed side such as the OD position during high speed traveling. In the vehicle speed range and the above low vehicle speed range, the deceleration expected when the driver releases the accelerator pedal is the vehicle speed V.
It was also found to change depending on the SP.

Therefore, as shown in FIG. 16, assuming that the reference value Gc is acceleration = -0.06G, which is the reference expected by the driver, the constant velocity region constituted by the predetermined acceleration range ΔG is
The engine braking or inertia according to the driver's expectation is changed according to the magnitude of the vehicle speed VSP so that the value is larger than the reference value Gc in the low vehicle speed range and approaches the reference value Gc as the vehicle speed increases in the high vehicle speed range. The vehicle acceleration is determined so that the vehicle can travel, and the speed at which the target input speed of the continuously variable transmission 2 is changed (correction amounts DDSRDN, DDSRUP) is controlled by using the vehicle acceleration as a target value.

Above and below in the figure of the constant velocity region, the above step S1
An acceleration side threshold value VSPOVLM and a deceleration side threshold value VSPUDLM that determine the acceleration range and the deceleration range at 13 and 114.
Are respectively provided below, and these threshold values VSPO
The setting of VLM and VSPUDLM will be described in detail.

3. A acceleration-side threshold value VSPOVLM The acceleration-side threshold value VSPOVLM that determines whether or not to strengthen the engine brake becomes smaller as the vehicle speed VSP increases (the deceleration side).
As described above, in the high vehicle speed range on highways, etc. as described above, it is possible to positively apply the engine brake when the accelerator pedal is released, and reduce the speed according to the driver's expectations. Can be done promptly.

Furthermore, when the vehicle speed VSP is a high vehicle speed (for example, 100 km / h) as the first predetermined value which is very large,
As shown by the broken line in FIG. 16, the threshold value VSPOVLM may be set so that the acceleration = 0 or less than 0. In this case, in coasting in the high vehicle speed range, the engine braking can be performed by accelerating even a little. As a result, the engine braking force can be increased more positively, the deceleration feeling felt by the driver can be increased, and the engine braking force according to the driver's expectation can be obtained.

On the other hand, when the vehicle speed VSP is a very low vehicle speed as a second predetermined value (for example, 20 Km / h) or less, as described above, even if the accelerator pedal is released, the driver can say nothing. Not expecting engine braking,
In such a low vehicle speed range, the threshold acceleration is set to a predetermined value which is considerably larger than 0, for example, 0.1 G or more so that the engine braking is not exerted as much as possible even if the vehicle acceleration increases to some extent. In the low vehicle speed range, smooth coasting can be performed according to the driver's expectations.

The acceleration side threshold value VSPOVLM between the low vehicle speed range and the high vehicle speed range is set so that the acceleration gradually decreases, and is set to the lower right as shown in FIGS.

3. B Deceleration-side threshold value VSPUDLM The deceleration-side threshold value VSPUDLM that determines whether or not to weaken the engine brake decreases the acceleration that becomes a predetermined threshold value as the vehicle speed VSP increases (the deceleration increases. Is set to, for example, in the low vehicle speed range, VSPU is obtained from the above-mentioned acceleration of −0.06 G which is the reference.
The DLM is set to a large value and less than 0, while it is set to -0.1 G or less, which is smaller than the above-described acceleration = -0.06 G which is the reference in the high vehicle speed range.

When the accelerator pedal is released in a high vehicle speed range and the vehicle is coasting downhill, the threshold value VSPUDLM is set to a sufficiently small value even if the gradient of the downhill temporarily becomes gentle. Not affected by minute changes in the gradient,
For example, even if the downhill slope during coasting becomes gentle and the deceleration increases slightly, the engine braking force is not frequently weakened in response to changes in the slope because the vehicle acceleration is within the constant velocity range. It is possible to suppress excessive fluctuations in the input speed and perform smooth coasting in accordance with the expectations of the driver.

On the other hand, in the low vehicle speed range where the vehicle speed VSP is extremely low (for example, 20 Km / h or less), as described above, the driver does not expect engine braking at all, and thus, In the low vehicle speed range, the acceleration serving as the predetermined threshold value is set to a predetermined value slightly smaller than 0, for example, −0.
By setting it to 03G, etc., the target input speed is corrected so that it will become small when the vehicle acceleration is in the deceleration range even a little, and the engine braking is not applied as much as possible. The generation of deceleration can be positively suppressed according to expectations, and smooth coasting can be performed.

The deceleration-side threshold value VSPUDLM between the low vehicle speed range and the high vehicle speed range is also set so that the acceleration gradually decreases as in the acceleration side, and as shown in FIGS. Is set to.

[4. Overall Operation] For engine braking control, first, the acceleration TKRAMS6 generated by the vehicle is monitored to determine whether or not it is in the constant velocity region of the map in FIG. 12, and the vehicle acceleration is determined from the acceleration side threshold value VSPOVLM. If it is larger, it is determined to be in the acceleration range, and if the vehicle deceleration is greater than the deceleration side threshold value, it is determined to be in the deceleration range (step S113,
114). Then, the driver's deceleration intention is divided into cases depending on the operation state of the accelerator pedal (steps S123 to 1).
31), when the vehicle is coasting while continuing to release the accelerator pedal (step S140), if the vehicle acceleration is in the acceleration range, the correction target input rotational speed DSRENBR is set to the downshift correction amount DDSRDN obtained from the map of FIG. In addition, the target input speed of the continuously variable transmission 2 is largely corrected to increase the engine braking force (steps S141, S14).
3). On the other hand, if the vehicle acceleration is in the deceleration range, the upshift correction amount DDSRU is added to the corrected target input speed DSRENBR.
P is added to correct the target input speed of the continuously variable transmission 2 to be small and the engine braking force is weakened (step S145,
148).

The engine braking force during coasting is controlled by the corrected target input rotational speed DSRENBR so that the vehicle acceleration converges to the constant speed region of FIG.

When the inertia pedaling is started by releasing the accelerator pedal, the engine braking force expected by the driver is the vehicle speed V.
When the control is performed according to the SP, and the target input speed of the continuously variable transmission 2 is set as the target value as in the conventional example,
Sensitive reaction to changes in the slope and changes in the road surface, a sudden change in engine braking force occurs during coasting, but by controlling the engine brake with acceleration as the target value as in the present invention. It is possible to prevent the sudden acceleration / deceleration due to the change of the gradient, and to smoothly change the engine brake continuously, which enables smooth coasting. The engine brake can be smoothly and continuously controlled in response to changes in the load of the auxiliary machinery.

Then, the threshold value VSP for judging the acceleration
When OVLM and VSPUDLM are changed according to the vehicle speed VSP, the deceleration feeling expected by the driver during coasting differs depending on the vehicle speed VSP that changes during high-speed traveling or during traffic congestion on highways and general roads. Even if the vehicle speed V
Since the acceleration (constant velocity range), which is the target value, can be changed according to the SP, it is possible to realize the feeling of deceleration that the driver expects without giving discomfort or discomfort, and continuously variable transmission. It is possible to dramatically improve the drivability and riding comfort of a vehicle equipped with a machine.

[0104]

As described above, according to the first aspect of the present invention, the shift control means changes the gear ratio so that the input shaft speed of the continuously variable transmission matches the target input speed according to the operating condition of the vehicle. Although the means is controlled, when the driver releases the accelerator pedal to coast, the target input speed is corrected using the acceleration set according to the threshold value as a target value. The engine braking force does not fluctuate excessively in response to subtle changes in the engine, and it is possible to control the engine braking force smoothly. If it exceeds, the target input speed is corrected to increase and the engine braking is strengthened, but the threshold value for determining the acceleration decreases in accordance with the increase of the vehicle speed, so in the low vehicle speed range. Some acceleration Never engine brake is increased even while the high vehicle speed range it is possible to enhance the aggressive engine braking if the acceleration state,
During coasting, it is possible to obtain the feeling of deceleration that the driver expects according to the vehicle speed, eliminate the discomfort and discomfort of the conventional example, and the drivability of the vehicle equipped with a continuously variable transmission. And, it becomes possible to dramatically improve the riding comfort.

Further, in the second invention, the threshold value for determining the acceleration is larger than 0 in the low vehicle speed range where the vehicle speed is equal to or lower than the first predetermined value, and is higher than 0 in the high vehicle speed range where the vehicle speed is equal to or higher than the second predetermined value. Since it is set to a small value, it is possible to forcibly intensify the engine brake even in the low vehicle speed range even if the vehicle is slightly accelerating to allow coasting, but to strengthen the engine brake when coasting in the high vehicle speed range. This makes it possible to reliably achieve a feeling of deceleration according to the driver's expectation that varies depending on the vehicle speed during coasting, and to further improve the drivability and riding comfort of the vehicle equipped with the continuously variable transmission. It is possible to improve.

Further, in the third aspect of the invention, when the driver releases the accelerator pedal to coast, the target input speed is corrected with the acceleration set according to the threshold value on the deceleration region side as the target value. The engine braking force does not fluctuate excessively in response to a slight change in the gradient as in the conventional example, and the engine braking force can be smoothly controlled. In a deceleration range smaller than a predetermined threshold value, the target input speed is corrected to be smaller and the engine brake is weakened, but the threshold value for determining the acceleration decreases as the vehicle speed increases. When the vehicle decelerates in the low vehicle speed range, the engine brake is quickly weakened to promote coasting, while in the high vehicle speed range, the engine brake is weakened even if the deceleration increases slightly (the acceleration decreases). It is possible to prevent excessive fluctuations in engine braking force even if the gradient changes during coasting on a downhill or the like.When coasting, a feeling of deceleration that differs according to the vehicle speed depending on the driver's expectations is provided. This can be realized, and the drivability and riding comfort of the vehicle equipped with the continuously variable transmission can be further improved.

Further, according to the fourth aspect of the present invention, the threshold value for determining the acceleration is set to be smaller than 0 in a low vehicle speed range where the vehicle speed is equal to or lower than a predetermined value and set to a predetermined value in the vicinity of 0. When the vehicle is in a decelerating state even a little, it is possible to weaken the engine brake to promote coasting and prevent frequent deceleration due to the engine braking in the low vehicle speed range, thus reducing the feeling of deceleration that meets the driver's expectations in the low vehicle speed range. Therefore, the drivability and riding comfort of the vehicle equipped with the continuously variable transmission can be further improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of a shift control device showing 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 shows details of engine brake correction control, and shows a flowchart showing a search process of a correction control range and an acceleration / deceleration determination threshold value.

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

FIG. 6 is a flow chart showing a case-by-case process according to a target input speed correction amount search and 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 flow chart showing a rotation limit check process of the same.

FIG. 11 shows the throttle opening TVO as a parameter.
The shift map which shows the control target input rotation speed DSRREV according to the vehicle speed VSP.

FIG. 12 is a determination map of an acceleration / deceleration range according to a vehicle speed VSP.

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

FIG. 14 is a graph showing the relationship between the vehicle speed VSP and the deceleration expected by the driver during coasting.

FIG. 15 is a conceptual diagram showing setting of a target acceleration range according to the present invention.

FIG. 16 is a graph showing an example of an acceleration / deceleration range determination map according to a vehicle speed VSP.

FIG. 17 is a claim correspondence diagram corresponding to claim 1 or claim 2;

FIG. 18 is a claim correspondence diagram corresponding to claim 3 or claim 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 engine 2 continuously variable transmission 3 drive shaft 4 fuel injection valve 5 speed ratio changing means 6 engine control controller 7 speed change 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 Acceleration detection means 52 Opening degree detection means 53 Acceleration comparison means 53 'Deceleration comparison means 54 Engine brake increase correction amount calculation means 54' Engine brake decrease correction amount calculation means 55 Corrected target input speed setting means 56 Threshold Value change means

Claims (4)

[Claims] 1. A gear ratio changing means for changing a gear ratio of a continuously variable transmission, and a target input rotation speed of an input shaft of the continuously variable transmission according to a driving state of a vehicle, and the input shaft rotation speed. In a shift control device for a continuously variable transmission, which includes a shift control means for controlling the shift ratio changing means so that the speed of the vehicle is equal to a target input speed, an acceleration detecting means for detecting a vehicle acceleration, and an accelerator pedal operation. An opening detection means for detecting the situation, an acceleration comparison means for comparing the detected acceleration with a predetermined threshold value when the opening detection means detects the release of the accelerator pedal, and the acceleration threshold An engine brake increase correction amount calculation means for correcting the target input speed to increase when the value exceeds the value; a corrected target input speed setting means for adding the correction amount to the target input speed; And a threshold value changing means for decreasing the threshold value according to an increase in vehicle speed, wherein the shift control means controls the gear ratio changing means based on the corrected target input rotation speed. Shift control device for continuously variable transmission. 2. The threshold value changing means sets the threshold value to a predetermined value larger than 0 in a low vehicle speed range where the vehicle speed is equal to or lower than a first predetermined value, while the vehicle speed is equal to or higher than a second predetermined value. The shift control device for a continuously variable transmission according to claim 1, wherein the threshold value is set to a predetermined value smaller than 0 in the high vehicle speed range. 3. A gear ratio changing means for changing a gear ratio of a continuously variable transmission, and a target input rotation speed of an input shaft of the continuously variable transmission according to a driving state of a vehicle, and the input shaft rotation speed. In a shift control device for a continuously variable transmission, which includes a shift control means for controlling the shift ratio changing means so that the speed of the vehicle is equal to a target input speed, an acceleration detecting means for detecting a vehicle acceleration, and an accelerator pedal operation. An opening detection means for detecting the situation, a deceleration comparison means for comparing the detected acceleration with a predetermined threshold value when the opening detection means detects the release of the accelerator pedal, and the acceleration is Engine brake reduction correction amount calculation means for correcting the target input speed to be smaller when it is smaller than a threshold value, and corrected target input speed setting means for subtracting the correction amount from the target input speed. Threshold value changing means for decreasing the threshold value in accordance with an increase in vehicle speed, wherein the shift control means controls the gear ratio changing means based on the corrected target input speed. And a shift control device for a continuously variable transmission. 4. The threshold value changing means sets the threshold value to a predetermined value smaller than 0 and near 0 in a low vehicle speed range where the vehicle speed is equal to or lower than a predetermined value. A shift control device for a continuously variable transmission as described.