JP2000320660A - Vehicle speed control device - Google Patents

Abstract

(57) [Summary] In a speed control device for a vehicle having a continuously variable transmission, when performing constant speed traveling control for controlling a vehicle speed V to a target vehicle speed VD in accordance with a constant speed traveling command of a driver, When running on a slope, fuel cuts are prevented from being interrupted, and acceleration and deceleration shocks are prevented. Also, insufficient deceleration due to insufficient engine braking is prevented. A speed ratio (ratio) i is controlled so that a vehicle speed V becomes a second target vehicle speed (higher than the target vehicle speed) when there is a deceleration request with a throttle opening θTH fully closed, more specifically, Control to the low side. Alternatively, control is performed on the low side so as to reach the target vehicle speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed control device, and more particularly, to a vehicle speed control device having a continuously variable transmission.

[0002]

2. Description of the Related Art An apparatus disclosed in Japanese Patent Application Laid-Open No. 10-29448 is known as a constant speed traveling control apparatus for a vehicle having a continuously variable transmission. This constant-speed traveling control device has a following traveling function. When it is determined that the vehicle is following the vehicle, the speed ratio of the continuously variable transmission is fixed, and the surplus torque is determined. The fluctuation of the engine speed is reduced by enriching the air-fuel ratio of the engine, thereby suppressing the fluctuation of the engine speed.

[0003]

Generally, in the constant-speed running control, the throttle opening is finely and promptly operated to maintain the vehicle speed at the target vehicle speed, as compared with a case where the driver operates the accelerator by himself / herself. However, if the throttle is driven to the fully closed position when traveling on a downhill while controlling at a constant speed, the engine control device executes fuel cut, thereby reducing the vehicle speed.

On the other hand, as a result of the constant speed traveling control device opening the throttle opening and increasing the vehicle speed, the engine control device interrupts the fuel cut. Next, as the vehicle speed increases, the constant-speed cruise control device returns the throttle to the fully closed position again, so that the engine control device resumes fuel cut.

[0005] As described above, when the vehicle is traveling on a downhill while executing the constant speed traveling control, the fuel cut is intermittent, which may cause an acceleration / deceleration shock to the driver.

Similarly, when a vehicle equipped with a continuously variable transmission is traveling on a downhill or an uphill while executing constant speed traveling control, the throttle is moved to a fully closed position to reduce the speed because the vehicle speed exceeds a target vehicle speed. When driven, the control device of the continuously variable transmission controls the ratio (gear ratio) to the high side, and as a result, the engine braking force may decrease and the deceleration force may become insufficient.

[0007] Regarding these points, the above-mentioned prior art discloses a constant speed traveling control device for a vehicle provided with a continuously variable transmission, but when it is determined that the vehicle is following, the transmission ratio of the continuously variable transmission is fixed. However, they did not solve the above-mentioned problems.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art, and to provide a continuously variable transmission connected to an internal combustion engine for continuously changing the engine output. Prevents the fuel cut from being interrupted even when traveling on a downhill while performing constant speed traveling control that controls the vehicle speed to the target vehicle speed in accordance with the command, so that there is no acceleration or deceleration shock to the driver To provide a vehicle speed control device.

Further, in a vehicle having a continuously variable transmission connected to an internal combustion engine for continuously changing the engine output, a constant speed traveling control for controlling the vehicle speed to a target vehicle speed in accordance with a constant speed traveling command from a driver. A second object of the present invention is to provide a vehicle speed control device that prevents a decrease in engine braking force even when traveling on a downhill road or an uphill road while executing a vehicle, so that a deceleration force is not insufficient. And

[0010]

In order to achieve the first object, the present invention provides a continuously variable transmission connected to an internal combustion engine for continuously changing the engine output. A speed control device for controlling the vehicle speed to a first target vehicle speed in accordance with a driver's constant speed travel command, wherein at least a throttle opening of a throttle valve of the internal combustion engine is provided. And operating state detecting means for detecting an operating state including a vehicle speed of the vehicle, and shift control means for controlling a speed ratio of the continuously variable transmission based on at least the detected throttle opening and vehicle speed, Throttle fully-closed opening determining means for determining whether or not the detected throttle opening is fully closed, and determining whether or not there is a deceleration request, more specifically, on a downhill road And / or comparing the detected vehicle speed with the first target vehicle speed to determine whether or not there is a deceleration request. The shift control unit includes: When it is determined that the throttle opening is in the fully-closed opening and the deceleration request is present, the speed ratio of the continuously variable transmission is controlled so that the detected vehicle speed becomes the second target vehicle speed. Configured.

When the detected throttle opening is at the fully-closed opening and it is determined that there is a deceleration request, the speed ratio is controlled so that the detected vehicle speed becomes the second target vehicle speed. Therefore, in other words, since the vehicle speed is controlled not through the throttle opening but through the gear ratio, the constant speed traveling control for controlling the vehicle speed to the first target vehicle speed in accordance with the driver's constant speed traveling command is performed. For example, it is possible to prevent the fuel cut from being interrupted even when the vehicle is traveling on a downhill road, thereby preventing the driver from being subjected to an acceleration / deceleration shock. Also, by preventing the fuel cut from being interrupted, fuel efficiency can be improved.

According to a second aspect of the present invention, the second target vehicle speed is set higher than the first target vehicle speed.

[0013] By configuring the second target vehicle speed to be higher than the first target vehicle speed, the region that can be controlled by the gear ratio (the throttle fully closed region) can be expanded. The control can be performed well, the intermittent fuel cut and the acceleration / deceleration shock can be better prevented, and the fuel consumption performance can be further improved.

According to a third aspect of the present invention, there is provided a continuously variable transmission connected to the internal combustion engine for continuously changing the engine output, and the vehicle speed is controlled to a target vehicle speed in accordance with a constant speed traveling command from the driver. A vehicle speed control device provided with a constant speed traveling control device, wherein at least a driving state detecting means for detecting a driving state including a throttle opening of a throttle valve of the internal combustion engine and a vehicle speed of the vehicle; And a shift control unit for controlling a speed ratio of the continuously variable transmission based on the throttle opening and the vehicle speed, and determining whether the detected throttle opening is the full closing opening. Degree determination means, and deceleration request determination means for comparing the detected vehicle speed with the target vehicle speed to determine whether or not there is a deceleration request. The configuration is such that the speed ratio of the continuously variable transmission is controlled so that the detected vehicle speed becomes the target vehicle speed when it is determined that the rottle opening is at the fully closed opening and the deceleration request is present. .

When the detected throttle opening is at the fully-closed opening and it is determined that there is a deceleration request, the speed ratio is controlled so that the detected vehicle speed becomes the target vehicle speed. By controlling the gear ratio to the low side, the engine braking force can be generated or increased.

[0016] Therefore, it is possible to prevent a decrease in engine braking force even when traveling on a downhill or an uphill while executing constant speed traveling control for controlling the vehicle speed to a target vehicle speed in accordance with a driver's constant speed traveling command. And the shortage of the deceleration force can be prevented.

[0017]

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

FIG. 1 is a schematic diagram generally showing a vehicle speed control device according to the present invention.

In FIG. 1, reference numeral 10 denotes an internal combustion engine (hereinafter referred to as "engine"), more specifically, a main body thereof. A throttle valve 14 is disposed in an intake pipe 12 connected to the engine 10. The throttle valve 14 is connected to the vehicle 16
A driver's seat (not shown) of an engine (not shown) is connected via a link mechanism (not shown) to an accelerator pedal 18 arranged on the floor of the driver's seat (not shown), and is operated in response to the driver's operation of the accelerator pedal. Open and close.

The output shaft (crankshaft) 20 of the engine 10
Is a belt-type continuously variable transmission 24 (hereinafter referred to as “CVT”).
Connected to. More specifically, the output shaft 20 of the engine 10 is connected to a CV via a dual mass flywheel 26.
It is connected to the input shaft 28 of T24.

The CVT 24 has an input shaft 28 and a counter shaft 3
0, a metal V-belt mechanism 32 disposed between the input shaft 28, a planetary gear type forward / reverse switching mechanism 36 disposed between the input shaft 28 and the drive-side movable pulley 34, a counter shaft 30 and a differential mechanism 40. And a start clutch 42 disposed between the two. Differential mechanism 40
Transmitted to the left and right drive wheels (not shown) via a drive shaft (not shown).

The metal V-belt mechanism 32 includes a drive movable pulley 34 disposed on the input shaft 28 and a counter shaft 3.
The pulley comprises a driven movable pulley 46 disposed above the pulley and a metal V-belt 48 wound between the two pulleys.

In the CVT 24, a regulator valve group (not shown) for determining a pulley control oil pressure to be supplied to the drive-side cylinder chamber 50 and the driven-side cylinder chamber 52 of the metal V-belt mechanism 32; 6
Shift control valve group 54 for supplying pulley control oil pressure to zero
The pulley side pressure is set so that slippage of the V-belt 48 does not occur, the pulley width of both pulleys 34 and 46 is changed, and the winding radius of the V-belt 48 is changed. The gear ratio (ratio) i is changed steplessly.

The starting clutch 42 is a clutch that controls on (engagement) and off (release) power transmission between the counter shaft 30 and the differential mechanism 40. When this clutch is turned on (engaged), the metal V-belt mechanism 32 The engine output shifted by the transmission is divided and transmitted to left and right wheels (not shown) by differential mechanism 40 via gears 58, 60, 62, 64. When the starting clutch 42 is off (disengaged), the CVT 24 is in a neutral state.

A branch pipe 68 is connected to the intake pipe 12 downstream of the throttle valve 14, and the branch pipe 68 is connected at the other end to a throttle actuator 70. The throttle actuator 70 includes a vacuum valve (electromagnetic solenoid valve) 72 for opening and closing the branch pipe 68 and a diaphragm (not shown) forming a negative pressure chamber connected to the branch pipe 68.

The opening degree of the branch pipe 68 changes by driving the vacuum valve 72, and the diaphragm is displaced by increasing or decreasing the intake negative pressure in the negative pressure chamber. A link 74 is connected to the diaphragm, and the link 74 is connected to the throttle valve 14 at the other end.

Therefore, the opening of the throttle valve 14 can be controlled by adjusting the drive of the vacuum valve 72. Thus, the throttle actuator 70 is configured as a negative pressure type actuator.
The details are described in Japanese Patent Application Laid-Open No.
Since the details are described in No. 07616, the explanation will be limited to this extent.

When the driver operates the accelerator via the accelerator pedal 18 while the throttle valve 14 is being driven by the throttle actuator 70, the driver's accelerator operation has priority, and the throttle valve 14 is controlled by the throttle actuator 70. Is opened and closed according to the driver's intention against the driving force of the vehicle. Throttle actuator 7
0 is set to a non-energized position (initial position) corresponding to the throttle opening fully closed position when the constant speed traveling command is not input.

Although not shown in the drawings, the apparatus according to the present invention includes a radar device, measures the distance between the vehicle and the preceding vehicle via the radar device, and controls the traveling speed at a constant speed. It is also possible to perform follow-up running control for keeping the inter-vehicle distance to the vehicle at a predetermined value.

A crank angle sensor 90 is provided at an appropriate position near the camshaft (not shown) of the engine 10, and outputs a signal proportional to the crank angle (counting the crank angle to calculate the engine speed NE). Output. In addition, the intake pipe 12
At an appropriate position downstream of the throttle valve 14, an absolute pressure sensor 92 is provided, and outputs a signal proportional to the absolute pressure (engine load) PBA in the intake pipe.

A water temperature sensor 94 is provided at an appropriate position of a cylinder block (not shown) to output a signal proportional to the engine cooling water temperature TW, and a throttle opening sensor 96 is provided near the throttle valve 14. And outputs a signal proportional to the throttle opening θTH.

In the CVT 24, a first rotation speed sensor 100 is provided near the input shaft 28, and outputs a signal proportional to the rotation speed NDR of the input shaft 28, and a second rotation speed sensor 100 near the driven side pulley 46. Is provided, and the rotation speed of the driven side pulley 46, that is, the rotation speed ND of the input shaft (counter shaft 30) of the starting clutch 42 is provided.
A signal proportional to N is output. A third rotation speed sensor 104 is provided near the gear 58, and the rotation speed of the gear 58, that is, the rotation speed NOU of the output shaft of the starting clutch 42 is provided.
A signal proportional to T is output.

Further, a vehicle speed sensor 1 is provided near a drive shaft (not shown) connected to the differential mechanism 40.
06 is provided to output a signal proportional to the vehicle speed V. A position switch 108 is provided near a shift lever (not shown) on the floor of the driver's seat, and outputs a signal proportional to the range position (D, N, P,...) Selected by the driver. I do.

This apparatus includes an engine control unit 110 composed of a microcomputer and a CVT control unit 112 also composed of a microcomputer. The outputs of the crank angle sensor 90, the absolute pressure sensor 92, the water temperature sensor 94, and the throttle opening sensor 96 in the above-described sensor group are input to the engine control unit 110. The engine control unit 110 controls the engine 10 based on the input value.

Further, a throttle opening sensor 96, a vehicle speed sensor 106, first to third rotation speed sensors 100 and 1 are provided.
Outputs of the switches 02 and 104 and the position switch 108 are input to the CVT control unit 112. The CVT control unit 112 controls a ratio (speed ratio) i via the valve group based on the input value.

Specifically, the CVT control unit 112 calculates a target engine speed NED by searching a shift map (described later) from the detected vehicle speed V and throttle opening θTH, and then calculates the calculated target engine speed NED. To realize N
DR target value (target NDR) is calculated, and the calculated target N
The movable pulley 34,
46 is driven to control the ratio i.

That is, since NDR is the rotation speed of the drive-side movable pulley 34 of the CVT 24, the ratio i can be uniquely determined by defining a target value (target NDR) for the vehicle speed V.

This device also includes a cruise (constant speed running) control unit 120 also composed of a microcomputer.
6 and the output of the vehicle speed sensor 106
20.

A set SW (switch) 122 for inputting a driver's constant speed driving intention and a set vehicle speed (target vehicle speed) is provided near a steering wheel (not shown) arranged in a driver's seat of the vehicle 16. , Resume switch to return after interrupting constant speed driving command by brake operation, etc.
A (switch) 124 and a cancel SW (switch) 126 for canceling the constant speed traveling command are provided.

A brake SW (switch) 128 is provided near a brake pedal (not shown), and outputs an ON signal when the driver depresses the brake pedal to perform a brake operation.

The output of the above switch is input to the cruise control unit 120. The cruise control unit 120 uses the switch output to drive the driver at a constant speed (auto cruise).
Recognizing the intention, the control unit 10 executes the constant speed traveling control via the throttle actuator 70 as described later, and executes the following traveling control via the electromagnetic valve 86 as necessary.

Although not shown, the engine control unit 1
10, CVT control unit 112 and cruise control unit 120
Are configured to be able to communicate with each other.

Next, the operation of this device will be described.

FIG. 2 is a flowchart showing the operation. The illustrated program is an operation performed by the CVT control unit 112, and is executed every predetermined time, for example, every 20 msec.

First, the vehicle speed V and the throttle opening θTH detected in S10 are read, and the program proceeds to S12, in which a parameter PNOAVE, which indicates a running load acting on the vehicle, based on the detected vehicle speed V and throttle opening θTH.
PKUAVE, more specifically, a parameter PNOAVE indicating a vehicle uphill gradient or a parameter PKUAVE indicating a downhill gradient is calculated.

This calculation is described in detail in Japanese Patent Application Laid-Open No. Hei 5-71625, which was previously proposed by the present applicant. However, when outlined with reference to FIG. 3, the vehicle speed V and the throttle opening θTH are calculated in advance. The expected acceleration expected for the vehicle 16 when traveling on a flat road is calculated for the third speed according to the set characteristics.

On the other hand, the actual acceleration actually generated by the vehicle 16 is obtained from the first-order difference value of the vehicle speed V, and a correction coefficient kn is calculated from the vehicle speed V and the throttle opening θTH according to a preset characteristic. Is corrected to a value equivalent to the third speed.

Next, the calculated expected acceleration and actual acceleration are compared to calculate a difference, and the average value is calculated. That is, when the difference obtained by subtracting the actual acceleration from the expected acceleration is a positive value, the value is used as PNO (the average value is PNOAVE, a parameter indicating the gradient of uphill). If the difference is a negative value, a difference obtained by subtracting the expected acceleration from the actual acceleration is a positive value, and the value is set as PKU (the average value is PKUAVE, a parameter indicating a downhill gradient).

In the technique proposed above, one of five types of shift maps for flat roads and light climbing is selected from the calculated parameters PNOAVE and PKUAVE, and the gear ratio is controlled in accordance with the selected shift map. However, in this embodiment, of the calculated parameters PNOAVE and PKUAVE, PKUAVE is used for downhill road traveling determination described later.

Then, the program proceeds to S14, in which it is determined whether or not the bit of the flag FAC is set to "1". This flag is set to 1 when the driver's constant speed traveling command is input in the processing performed by the cruise control unit 120. Therefore, the processing in this step means determining whether or not a constant speed traveling command has been input.

Here, the processing performed by the cruise control unit 120 will be described.

FIG. 4 is a flow chart showing the processing. The illustrated program is executed, for example, every 200 msec.

In the following, it is determined in S100 whether the cancel SW (switch) 126 is turned on, in other words, whether or not the driver has canceled the constant speed traveling command. It is determined whether the brake SW (switch) 128 is on, that is, whether a brake operation has been performed.

When the result in S102 is NO, the program proceeds to S104, in which it is determined whether or not the set SW (switch) 122 has been turned on, in other words, whether or not the driver's intention to drive at a constant speed and the set vehicle speed have been input. .

When the result in S104 is affirmative, the program proceeds to S106, in which the set vehicle speed (target vehicle speed) VD input via the set SW (switch) 122 is detected and stored, and the process proceeds to S108.
To set the bit of the flag FAC to 1. That is, it is determined that the driver's constant speed traveling command has been input.

Next, the routine proceeds to S110, where an initial process is executed.

That is, the throttle actuator 70 is in the non-energized position (a position corresponding to the fully closed position of the throttle) until the constant speed traveling command is input. 7
A current command value ICMD required to drive 0 (more specifically, the link 74) is calculated and output to the vacuum valve 72 via a drive circuit (not shown) to be driven.

Then, the program proceeds to S112, in which the above-mentioned initial processing is completed, that is, the throttle actuator 70 is moved to a position corresponding to the throttle opening at the time of inputting the constant speed traveling command.
It is determined whether or not has been driven.

When the result in S112 is negative, the subsequent processing is skipped. When the result is affirmative, the process proceeds to S114, in which a PID control law or the like is used according to the deviation between the set vehicle speed (target vehicle speed) VD and the detected vehicle speed V. A current command value ICMD to be supplied to the vacuum valve 72 of the throttle actuator 70 is calculated.

That is, since the initial processing has been completed, the flow shifts to the essential constant speed traveling control (auto cruise control) in which the detected vehicle speed V converges to the target vehicle speed VD.

When the result in S100 or S102 is affirmative, the program proceeds to S116, where the bit of the flag FAC is set to 0.
Reset to. When the result in S104 is NO, S
The routine proceeds to 118, where it is determined whether or not the resume SW (switch) 124 is turned on, that is, whether or not the driver has input an intention to restart the constant speed traveling control.

If the result in S118 is affirmative, S12
0, the stored set vehicle speed (target vehicle speed) VD stored is read, and the process proceeds to S108.
Proceeding to 116, the bit of the flag FAC is reset to 0.

Returning to the description of FIG. 2, when the result in S14 is NO, the program proceeds to S16, in which CVT shift control is performed.

Specifically, as described above, the CVT control unit 112 determines a ratio i by searching a shift map having the characteristics shown in FIG. 5 from the detected vehicle speed V and throttle opening θTH, and determines the ratio i. The CVT 24 is controlled so that

More specifically, the CVT control unit 112
From the detected vehicle speed V and throttle opening θTH, a shift map having the characteristics shown in FIG.
The ED is calculated, the target NDR for realizing the calculated target engine speed NED is calculated, and the movable pulleys 34 and 46 are driven via the valve group 54 and the like so as to achieve the target NDR.

The movable pulleys 34 and 46 may be driven immediately according to appropriate characteristics from the target engine speed NED, or a target ratio between NDR and NDN is calculated from the target engine speed NED and becomes the target ratio. The movable pulleys 34 and 46 may be driven as described above. In this specification, the control of the ratio (gear ratio) i or the control of the CVT means that any one of the three cases is performed.

Next, the process proceeds to S18, where the bit of the flag FCVT is reset to zero. This flag will be described later.

On the other hand, when the result in S14 is affirmative, the program proceeds to S20, in which it is determined whether or not the detected throttle opening θTH is zero, that is, whether or not the throttle opening θTH is at the fully closed opening.
Note that the throttle opening θTH is actually configured to be a fully closed opening at an opening slightly larger than zero, but here, zero is set as the fully closed opening for convenience of explanation.

When the result in S20 is NO, the program proceeds to S22,
It is determined whether or not fuel cut (fuel supply stop) is being executed. The fuel cut is executed when the engine control unit 110 is in an operating state in which the throttle opening θTH is at the fully-closed opening, is decelerating, and the engine speed is equal to or higher than a predetermined value. When determining whether or not to execute the fuel cut, the determination may be made in addition to the intake pipe absolute pressure PBA.

Therefore, the fuel cut is normally not executed unless the throttle opening θTH is not the full-closed opening, but may be executed even if the throttle-opened θTH is not the full-closed. .

When the result in S22 is negative, the program proceeds to S16, where normal gear shifting control is performed.
Proceed to. The same applies when the result in S20 is affirmative. Note that S
When the determination in step 20 is negative and it is determined that the throttle opening is not fully closed, the process proceeds to step S23 when it is determined that the fuel cut is being executed, as described above, in order to avoid interruption of the fuel cut. is there.

In S23, the parameter PKUAVE indicating the descending slope is compared with a predetermined value (for example, a value equivalent to zero), and whether or not the vehicle 16 is traveling on a descending slope, in other words, there is a deceleration request. It is determined whether or not the determination is negative. If the result is negative, the control according to the present embodiment is not in the expected traveling state, so the process proceeds to S16, and if the result is positive, the process proceeds to S24.

In S24, similarly, the detected vehicle speed V is compared with the target vehicle speed VD. More specifically, the detected vehicle speed V is compared with a value obtained by adding a predetermined value α to the target vehicle speed VD. In other words, it is determined whether there is a deceleration request.

If the result in S24 is negative, the control according to the present embodiment is not in the expected running state, so the process proceeds to S16. If the result is affirmative, the process proceeds to S26, in which the aforementioned FCVT bit is set to 1. Is determined. In addition, since the processes of S23 and S24 are both performed based on whether or not there is a deceleration request, one of S23 and S24 may be omitted.

Since this flag has been reset to 0 in S18, this determination is normally denied and the routine proceeds to S28, where CVT vehicle speed control (described later) is performed, and the routine proceeds to S30, where the cruise control unit 120 prohibits throttle control. To communicate.

Then, the program proceeds to S32, in which the flag FC
Set the bit of VT to one. That is, setting the bit of this flag to 1 means that the CVT vehicle speed control is being executed, and resetting it to 0 means that it is not being executed.

Accordingly, in the next and subsequent program loops, the determination in S26 is affirmed, and the process proceeds to S34, where it is determined whether the ratio i is equal to or less than a predetermined value iH. Here, the predetermined value iH means an appropriate value on the high side. When affirmed in S34, the process proceeds to S16, and when denied, the process proceeds to S28 to perform CVT vehicle speed control.

Here, the CVT vehicle speed control will be described.

As described above, when the throttle is driven to the fully closed position while traveling on a downhill while controlling the constant speed, the fuel cut is executed and the vehicle speed is reduced. Opening and increasing the vehicle speed will cause a fuel cut interruption.

When the vehicle speed increases, the throttle is returned to the fully closed position again, and the fuel cut is restarted. Thus, the fuel cut is intermittent, which may cause an acceleration / deceleration shock to the driver.

Therefore, in this embodiment, when it is determined that the throttle opening θTH is at the fully-closed opening and the vehicle 16 is traveling on a downhill, the vehicle speed V is increased to the second speed.
(I.e., different from the target vehicle speed (the first target vehicle speed) VD of the above-mentioned constant speed traveling control). The second target vehicle speed is
It is set higher than target vehicle speed VD.

More specifically, the vehicle speed control is controlled by a ratio i. More specifically, by changing the ratio i from a high side to a low side, an engine braking force is generated, thereby decelerating. . Therefore, in the determination of S34, it is determined whether or not there is room to generate the engine braking force by changing to the low side, and the predetermined value iH
Selects and uses an appropriate value sufficient to judge it.

That is, the inventors of the present invention have focused on the fact that the above-mentioned inconvenience is caused by controlling the vehicle speed through the throttle opening θTH, and made the present invention. The present invention has been made by paying attention to the fact that control is possible via the ratio i.

The above will be further described with reference to FIG.

When the second target vehicle speed VDC is referred to as VDC with respect to the target vehicle speed VD of the constant speed traveling control, the second target vehicle speed VDC is set slightly higher than the target vehicle speed (first) VD. For example, if VD is 100 km / h, V
Set DC to 102 km / h.

The CVT control unit 112 controls the vehicle speed V using VDC as a target value in the CVT vehicle speed control. That is, as shown in FIG. 6, the detected vehicle speed V is equal to the target vehicle speed VD.
When it exceeds C, the ratio i is increased (changed to the low side) to generate engine braking force and decelerate,
When the detected vehicle speed V is lower than the target vehicle speed VDC, the ratio i is controlled to be small (changed to the high side) and raised.

The broken line in FIG. 6 shows the case where only the target vehicle speed VD is used. On the other hand, by setting the second target vehicle speed VDC beyond the target vehicle speed (first) VD, the range (time) in which the vehicle speed can be controlled by the ratio can be expanded.

In this embodiment, as described above, the second target vehicle speed VDC is set to exceed the target vehicle speed (first) VD, and the range (time) in which the vehicle speed can be controlled by the ratio is expanded. In other words, the time until the ratio i is changed to the high side is delayed to extend the throttle fully closed region.

Therefore, even when the fuel cut (F / C) is performed by the engine control unit 110, it is possible to effectively prevent the fuel cut from being interrupted, thereby preventing the driver from applying an acceleration / deceleration shock. The fuel consumption can be improved, and the fuel efficiency can be improved.

In the first embodiment, the running load (more specifically, the parameter indicating the downhill gradient) was calculated using the technique proposed earlier, and the calculated value was used for the determination of downhill road running. Alternatively, downhill traveling may be directly detected by providing an inclination sensor or the like.

FIG. 7 is a flow chart similar to FIG. 2, but showing the operation of the device according to the second embodiment of the present invention.

The second embodiment is intended to achieve the second object described above. That is, when a vehicle equipped with a continuously variable transmission is traveling on a downhill or an uphill while performing constant speed traveling control, if the vehicle speed exceeds the target vehicle speed and the throttle is driven to the fully closed position to reduce the speed, the The control device of the stepped transmission controls the ratio (gear ratio) to the high side. As a result, the engine braking force may be reduced and the deceleration force may be insufficient. The second embodiment solves such inconvenience. Intended.

In the following, the vehicle speed V and the throttle opening θTH detected in S200 are read, and
02, it is determined whether or not the bit of the flag FAC is set to 1;
Based on the detected vehicle speed V and throttle opening θTH, a shift map having the characteristics shown in FIG. 5 is searched to determine a ratio i, and the CVT 24 is controlled so as to achieve the ratio i.

On the other hand, if the result in S202 is affirmative, S20
6 and the detected vehicle speed V, as in the first embodiment.
Is compared with the target vehicle speed VD, and more specifically, the detected vehicle speed V
Is compared with a value obtained by adding the predetermined value α to the target vehicle speed VD, and it is determined whether or not the value is greater than that, in other words, whether or not there is a deceleration request.

When the result in S206 is negative, the program proceeds to S204, and when the result is affirmative, it is determined that there is a deceleration request, and the program proceeds to S208, where the detected throttle opening θTH is zero,
That is, it is determined whether or not the throttle opening θTH is at the fully closed opening. When the result in S208 is negative, the process proceeds to S204, and when the result is affirmative, the process proceeds to S210, and the CVT
Car speed control is performed.

[0096] The CVT control unit 112 executes the CVT of S210.
In the vehicle speed control, the ratio i is controlled (determined) so that the detected vehicle speed V becomes equal to the target vehicle speed VD.

More specifically, although it is determined that there is a deceleration request, since the throttle valve 14 is in the fully closed position, the ratio i is controlled to the low side. More specifically,
The deviation between the detected vehicle speed V and the target vehicle speed VD is determined, and as the deviation increases, the ratio i is increased, that is, the ratio i is controlled to a lower value.

As a result, the detected vehicle speed V can be controlled so as to be equal to the target vehicle speed VD, and by changing the ratio i to the low side, the engine braking force is generated or increased, thereby preventing shortage of the deceleration force. can do.

Since the second embodiment is configured as described above, that is, when the vehicle 16 equipped with the CVT 24 travels on a downhill while executing constant speed traveling control, the vehicle speed V exceeds the target vehicle speed VD. In this case, even when the throttle valve 14 is driven to the fully closed position for deceleration, the CVT control unit 1
12 is configured to control the ratio i to the low side instead of the high side, so that the engine braking force can be generated or increased. Therefore, the inconvenience described above can be solved.

As described above, in this embodiment, the continuously variable transmission (CVT 24) connected to the internal combustion engine (engine body 10) for continuously changing the engine output is provided, and the driver is driven at a constant speed. In a vehicle speed control device provided with a constant speed traveling control device (cruise control unit 120) for controlling a vehicle speed (V) to a first target vehicle speed (VD) according to a command, at least a throttle valve (1) of the internal combustion engine is provided.
4) operating state detecting means (throttle opening sensor 96, vehicle speed sensor 106, CVT control unit 112, S10) for detecting an operating state including the throttle opening (θTH) and the vehicle speed (V) of the vehicle, and at least A shift control means (CVT control unit 112, S16) for controlling a speed ratio (ratio i) of the continuously variable transmission based on the detected throttle opening and the vehicle speed is provided, and the detected throttle opening is Throttle fully-closed opening determining means (CVT control unit 112, S2
0) and determining whether there is a deceleration request, more specifically, determining whether the vehicle is on a downhill, and / or comparing the detected vehicle speed with the first target vehicle speed to reduce the speed. Deceleration request determining means (CVT) for determining whether there is a request
Control 112, S23, S24), wherein the shift control means determines that the detected vehicle speed is the full throttle opening and determines that there is a deceleration request, the detected vehicle speed is reduced to the second speed. (CVT control unit 11) to control the speed ratio of the continuously variable transmission so that the target vehicle speed (VDC) becomes 2.
2, S30).

Further, the second target vehicle speed (VDC) is
The first target vehicle speed (VD) is set to be higher than the first target vehicle speed (VD).

A continuously variable transmission (CVT) connected to an internal combustion engine (engine body 10) for continuously changing the engine output.
24) and a constant speed traveling control device (cruise control unit 120) for controlling the vehicle speed (V) to a target vehicle speed (VD) in accordance with a constant speed traveling command from the driver. Operating state detecting means (a throttle opening sensor 96, a vehicle speed sensor 106, and the like) for detecting an operating state including at least a throttle opening (θTH) of a throttle valve (14) of the internal combustion engine and a vehicle speed (V) of the vehicle;
A CVT control unit 112, S200) and a shift control unit (CVT control unit 112, S204) for controlling a speed ratio of the continuously variable transmission based on at least the detected throttle opening and vehicle speed. Throttle fully-closed opening determining means (CVT control unit 112, S20) for determining whether or not the detected throttle opening is fully closed.
8), and the detected vehicle speed (V) and the target vehicle speed (V
D), there is provided a deceleration request determining means (CVT control unit 112, S206) for determining whether or not there is a deceleration request, wherein the shift control means is configured such that the detected throttle opening is a fully closed opening. In addition, when it is determined that there is a deceleration request, the speed ratio of the continuously variable transmission is controlled so that the detected vehicle speed V becomes the target vehicle speed VD (CVT control units 112 and S210). .

Although the example of the constant speed traveling control (cruise control) has been described above, a function of following the preceding vehicle may be added.

Although the throttle actuator is of a negative pressure type, it may be of an electric type or a DBW type.

Although a continuously variable transmission of a metal belt type is used, a rubber belt type or a toroidal type may be used.
In addition, not only the continuously variable transmission but also the optimal gear position of the stepped transmission may be selected. The slip ratio of the lock-up clutch may be replaced with the slip ratio.

The structure of the transmission is not limited to that shown in the figure.
A torque converter may be connected to the output shaft 20 of the engine 10, and a torque converter may be used instead of the starting clutch 42. Also, dual mass flywheel 2
6 may be removed.

[0107]

According to the first aspect of the present invention, when it is determined that the detected throttle opening is at the fully-closed opening and there is a deceleration request, the detected vehicle speed is set to the second target vehicle speed. In other words, since the vehicle speed is controlled not through the throttle opening but through the speed ratio, the vehicle speed is controlled to the first speed according to the driver's constant speed traveling command. While the constant speed traveling control for controlling the vehicle speed to the target vehicle speed is executed, the fuel cut can be prevented from being interrupted even when traveling on a downhill, for example, so that acceleration / deceleration shock is not given to the driver. Also, by preventing the fuel cut from being interrupted, fuel efficiency can be improved.

According to the second aspect, by configuring the second target vehicle speed to be higher than the first target vehicle speed, an area where the speed ratio can be controlled (throttle fully closed area) is provided. Therefore, the vehicle speed can be controlled well, the intermittent fuel cut and acceleration / deceleration shock can be prevented, and the fuel efficiency can be further improved.

According to a third aspect of the present invention, when it is determined that the detected throttle opening is the fully-closed opening and there is a deceleration request, the speed is changed so that the detected vehicle speed becomes the target vehicle speed. Since the ratio is controlled, the engine braking force can be generated or increased by controlling the gear ratio to the low side.

Therefore, it is possible to prevent a decrease in engine braking force even when traveling on a downhill or an uphill while executing constant speed traveling control for controlling the vehicle speed to a target vehicle speed in accordance with a driver's constant speed traveling command. And the shortage of the deceleration force can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall vehicle speed control device according to the present invention.

FIG. 2 shows the operation of the device of FIG. 1, more specifically the CV therein;
5 is a flowchart showing the operation of a T control unit.

FIG. 3 is an explanatory diagram for explaining calculation of a parameter indicating a traveling load (more specifically, an uphill gradient or a downhill gradient) used in the processing of the flowchart in FIG. 2;

FIG. 4 is a flowchart showing an operation of a cruise control unit in the apparatus of FIG. 1;

FIG. 5 is an explanatory diagram showing characteristics of a shift map used in CVT shift control in the flowchart of FIG. 2;

FIG. 6 is a time chart showing the operation of the flow chart of FIG. 5;

FIG. 7 is a flowchart similar to FIG. 2, showing the operation of the device according to the second embodiment of the present invention, more specifically, the operation of the CVT control unit.

[Explanation of symbols]

 Reference Signs List 10 internal combustion engine (engine body) 14 throttle valve 16 vehicle 18 accelerator pedal 24 belt-type continuously variable transmission (CVT) 28 transmission input shaft 30 transmission counter shaft 32 metal V-belt mechanism 36 planetary gear type forward / reverse switching mechanism 42 start Clutch 70 Throttle actuator 72 Vacuum valve 74 Link 90 Crank angle sensor 92 Absolute pressure sensor 96 Throttle opening sensor 106 Vehicle speed sensor 110 Engine control unit 112 CVT control unit 120 Cruise control unit 122 Set switch 124 Resume switch 126 Cancel switch

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) F16H 59:44 63:06 (72) Inventor Hideaki Kotani 1-4-1 Chuo, Wako-shi, Saitama Stock Company In-house Honda R & D Co., Ltd. (72) Inventor Naoto 1000 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 3D041 AA22 AA31 AA33 AA41 AB01 AC06 AC09 AC18 AC19 AC20 AD02 AD04 AD14 AD23 AD31 AD41 AD47 AD51 AE04 AE08 AE11 AE36 AE45 AF09 3D044 AA01 AA14 AA41 AB01 AC03 AC05 AC07 AC08 AC15 AC21 AC24 AC26 AD04 AD17 AE14 AE15 3J052 AA01 AA04 AA14 CA21 GC03 GC13 GC23 GC43 GC44 GC46 HA11

Claims (3)

[Claims] 1. A continuously variable transmission connected to an internal combustion engine for continuously changing an engine output and controlling a vehicle speed to a first target vehicle speed in accordance with a constant speed traveling command from a driver. A vehicle speed control device comprising a control device, comprising: a. Operating state detecting means for detecting an operating state including at least a throttle opening of a throttle valve of the internal combustion engine and a vehicle speed of the vehicle; and b. Shifting control means for controlling a speed ratio of the continuously variable transmission based on at least the detected throttle opening and vehicle speed; c. Throttle full-closed opening determining means for determining whether the detected throttle opening is the full-closed opening, and d. Deceleration request determining means for determining whether there is a deceleration request,
And the shift control means is configured to, when it is determined that the detected throttle opening is at the fully-closed opening and the deceleration request is present, the detected vehicle speed be the second target vehicle speed. A speed control device for controlling the speed ratio of the continuously variable transmission. 2. The vehicle speed control device according to claim 1, wherein the second target vehicle speed is set higher than the first target vehicle speed. 3. A constant speed traveling control device which is connected to an internal combustion engine and continuously varies the engine output, and which controls a vehicle speed to a target vehicle speed in accordance with a driver's constant speed traveling command. A speed control device for a vehicle provided with: a. Operating state detecting means for detecting an operating state including at least a throttle opening of a throttle valve of the internal combustion engine and a vehicle speed of the vehicle; and b. Shifting control means for controlling a speed ratio of the continuously variable transmission based on at least the detected throttle opening and vehicle speed; c. Throttle full-closed opening determining means for determining whether the detected throttle opening is the full-closed opening, and d. Deceleration request determining means for determining whether there is a deceleration request by comparing the detected vehicle speed with the target vehicle speed, wherein the shift control means is configured such that the detected throttle opening is at a fully closed opening and A speed control device for controlling the speed ratio of the continuously variable transmission so that the detected vehicle speed becomes the target vehicle speed when it is determined that the deceleration request is issued.