JPS6261832A - Travel control unit for vehicle - Google Patents

Abstract

PURPOSE:To aim at reducing the fuel consumption of a vehicle and at improving the drive feeling thereof, by providing such an arrangement that the difference between an upper limit and a lower limit which are set by an upper and lower vehicle speed limit setting means increases as set speed increases. CONSTITUTION:The supply amount of fuel for an engine 20 is controlled to effect a moderate acceleration until the speed of a vehicle increases from a lower limit to an upper limit which are set within a constant speed travel range by a computer 30 with reference to a set vehicle speed unit 2, and therefore, when the vehicle sped reaches the upper limit, a clutch 10 is energized to cut off the transmission of drive power to wheels so that inertial travel is carried out until the vehicle speed decreases to the lower limit. In this case, setting is made such that the difference between the upper and lower limits increases as the set vehicle speed speed increases. Accordingly, by repeating moderate acceleration and inertial travel, it is possible to realize travel at a constant low speed with low fuel consumption, and further it is possible to reduce affection upon drive feeling, which is accompanied by vehicle speed changes during travel at a low speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a travel control device that maintains a vehicle speed at approximately a desired set value while driving the vehicle.

(Prior Art) In recent years, constant speed traveling devices that automatically maintain the vehicle speed of an automobile at a desired speed set by a driver have been put into practical use. This constant speed traveling device sets the vehicle speed as a target value for constant speed traveling by a set operation by the driver when the vehicle speed reaches a desired vehicle speed, and thereafter compares this set vehicle speed with the actual vehicle speed. Therefore, when a difference occurs between the two, the throttle valve of the engine is controlled according to the difference, thereby making the actual vehicle speed match the set vehicle speed.

In order to drive at a constant speed using such a device, it is necessary to always maintain the throttle valve opening at a predetermined opening so as to maintain the engine rotation corresponding to the set vehicle speed. When the vehicle speed is within a certain range, the clutch is disengaged to cut off the transmission of drive power between the engine and the wheels, causing the vehicle to coast, and during this time the engine is reduced to idle speed. By doing so, constant speed driving control with good fuel efficiency can be performed.

For this reason, for example, Japanese Unexamined Patent Publication No. 56-22113 proposes that a predetermined speed range is determined based on the set vehicle speed when a constant speed running condition occurs, and that the speed is set between the upper and lower limits in this range. 2. Description of the Related Art Vehicle travel control methods and devices have been proposed in which acceleration and coasting are repeated.

In this driving control, when the vehicle speed reaches the upper limit, the clutch is disengaged and the engine throttle valve is fully closed to allow coasting, and when the vehicle speed reaches the lower limit, the engine rotation is increased to a rotation corresponding to the vehicle speed, and then, By engaging the clutch, the engine speed is gradually increased, and the vehicle speed is controlled to perform gentle acceleration until it reaches the upper limit value, and the vehicle speed is maintained within a certain range determined by the upper and lower limit values, and the vehicle is driven at a constant speed. .

When performing constant speed driving control like this, the upper and lower limits are set with a certain width above and below the set vehicle speed, but if this width is too small, slow acceleration and coasting will be repeated frequently. Therefore, there is a possibility that the effect of reducing fuel consumption will not be obtained much. On the other hand, if this width is set too large, there is a problem that the vehicle speed fluctuation during constant speed driving becomes large, which is not favorable in terms of driving feeling.

(Object of the Invention) The present invention has been developed in view of the above-mentioned problems, and since the absolute vehicle speed is large at high vehicle speeds, even if the vehicle speed fluctuations are somewhat large, they do not bother the driver much and do not impair the driving feeling. In addition, at low vehicle speeds, running resistance is small (running resistance is approximately proportional to the square of the vehicle speed), so the deceleration during coasting is small, and coasting starts even if the vehicle speed fluctuation range for constant speed running is small. This was done in consideration of the fact that the time difference from 1 to the start of slow acceleration is relatively large, and the frequency of repetition of slow acceleration and coasting does not become very large. It is an object of the present invention to provide a vehicle travel control device that can change and set the difference between an upper limit value and a lower limit value according to a set vehicle speed.

(Structure of the Invention) The driving control device of the present invention is a device that maintains the vehicle speed within a predetermined range near the set vehicle speed by controlling the amount of fuel supplied to the engine to perform constant speed driving, and has a constant speed driving condition detection means. detects whether or not a constant speed running condition is occurring, and when the constant speed running condition occurs, when driving at a constant speed, the upper and lower vehicle speed limit setting means sets the constant speed running vehicle speed based on the set vehicle speed. An upper limit value and a lower limit value within the range are set, and until the vehicle speed reaches the upper limit value from the lower limit value, the fuel supply port to the engine is controlled by the slow acceleration means to perform slow acceleration.
When the vehicle speed reaches the upper limit, the coasting means activates a clutch, etc. to cut off the transmission of driving force from the engine to the wheels, allowing the vehicle to coast until the vehicle speed reaches the lower limit, resulting in constant speed driving. In this case, the difference between the upper limit value and the lower limit value is increased as the set vehicle speed increases.

(Embodiments) Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the overall configuration of a travel control device according to the present invention.

This device is controlled by controlling the clutch 10 on and off and controlling the opening of the throttle valve 26 by the throttle actuator 25 based on signals from the computer unit 30. computer unit 3
0 is 0N-OF of cruise control switch 30a
The computer unit 30 receives a signal from the brake switch 2 which detects the operation of the brake pedal 1 in conjunction with the brake pedal 1, and a signal from the brake switch 2 which detects the operation of the brake pedal 1 in conjunction with the accelerator pedal 3. A signal from the accelerator pedal position sensor 4 to detect, a signal from the engine stop detection sensor 21 to detect whether or not the engine 20 is stopped at the distributor,
A signal from the water temperature sensor 22 that detects the cooling water temperature of the engine 20, a signal from the throttle position sensor 23 that detects the opening degree of the throttle valve 26, a signal from the intake temperature sensor 24 that detects the intake temperature, and the output side from the clutch 10. A signal from a vehicle speed sensor 16 that detects the vehicle speed based on the rotation of the power transmission system at
5 and the electromagnetic control valve 13. The electromagnetic control valve 13 controls the hydraulic pressure supply to the clutch actuating cylinder 11 to connect and disconnect the clutch 10, and the hydraulic pressure sent from the electric pump 15 via the accumulator 14 is applied to the clutch actuating cylinder by the electromagnetic control valve 13. 11, the rod 11a is moved to either the left or right in the figure, and the clutch 10 is engaged or engaged via a lever 12.

FIG. 2 is a graph showing changes over time in vehicle speed, engine rotation, etc. when driving is controlled by the driving control device. This graph shows changes when the cruise control switch 30a is turned on at time A, and the upper limit value (V+ΔV) and lower limit value (V- Δ■) is determined, and from this state, the engine throttle opening degree is gradually opened and gradual acceleration is performed until the vehicle speed reaches the upper limit fin(V+ΔV). When the vehicle speed reaches the upper limit (at time 8), the clutch 10 is turned off, the throttle opening is fully closed at the same time, the engine rotation is reduced to the idling rotation, and the vehicle coasts in this state. During coasting, the vehicle speed gradually decreases due to running resistance, etc., and when this vehicle speed reaches the lower limit value (V-Δ■) (at time C), the clutch 10 is turned ON again, and the throttle opening and engine speed are reduced to this lower limit. It can be increased to a speed that matches the vehicle speed of the value. Thereafter, the throttle opening is gradually opened again, and gradual acceleration is performed until the vehicle speed reaches the upper limit value.

When performing this control, the permissible variation width Δ■ of vehicle speed for determining the upper limit value and lower limit value is set according to the set vehicle speed ■, and the variation range Δ■ is set to increase as the set vehicle speed ■ increases. be done.

This means that at high vehicle speeds, the absolute vehicle speed is large, so even if the vehicle speed fluctuates somewhat, it does not impair the driver's driving feeling, and at high vehicle speeds, the running resistance is large, so the vehicle speed decelerates during coasting. is large,
This is done in consideration of the fact that it is desirable to increase the fluctuation range and reduce the frequency of repetition of slow acceleration and coasting. Generally speaking, contrary to the above, when the vehicle speed is low, the absolute vehicle speed is small, so vehicle speed fluctuations have a large effect on the driving feeling, so it is desirable to reduce the fluctuation range, and because the running resistance at low vehicle speeds is small, coasting This takes into account the fact that the deceleration at the time of the vehicle is small and that even if the fluctuation width ΔV is made small, the frequency of repetition of slow acceleration and coasting does not increase too much.

Note that when the distance between the vehicle and the vehicle traveling ahead is small while driving, it is dangerous to increase the vehicle speed fluctuation width ΔV. The vehicle speed fluctuation width ΔV may be changed depending on the vehicle speed.

FIG. 3 is a block diagram showing the configuration of the computer unit 30. The computer unit 30 includes travel switching control blocks 31. Economy cruise control block 32. Auto cruise control block 33, normal driving control block 3
4. It consists of a throttle opening IIIIIII block 35 and a clutch control block 36.

The travel switching control block 31 has input lines 31a to 31.
f, 31m and output lines 319-31k are connected. The input line 31a receives the brake signal BR8W from the brake switch 2, the input line 31i receives the clutch signal CLSW from the clutch switch that detects clutch operation, and the input line 31C receives the cruise signal AC3W from the cruise switch. Input line 31d
From is the cruise method signal E from the cruise method switch.
CMOD receives the setting signal vssw from the vehicle speed set switch from the input line 31e, and the vehicle speed signal VS from the vehicle speed sensor 16 from the input line 31f.
The inter-vehicle distance signal VDIS from the distance sensor 28 is input from each of the distance sensors m.

The cruise switch is a switch that switches between normal driving and constant speed driving, and the cruise method switch switches between conventional constant speed driving (hereinafter referred to as auto cruise) and slow acceleration according to the present invention when constant speed driving is selected. This switch switches between constant-speed driving (hereinafter referred to as economy cruise), which repeats coasting and constant-speed driving.The vehicle speed set switch is a switch to set the vehicle speed for constant-speed driving, and these switches control the cruise control shown in Figure 1. A switch 30a is configured.

A clutch operation permission signal CLLJTCH is output from the output line 31g to the clutch control block 36, and a throttle opening control permission signal TH8W is output from the output line 31h to the throttle opening control block 35. The clutch operation permission signal CLUTCH is an 0N-OFF signal,
The clutch control signal CLB on the output line 32d from the economy cruise control block 32 is input to the clutch control block 36 only when the ON signal is output. There are three types of throttle opening control permission signal TH3W, 1.2.3. When signal 1 is signal THB1 from economy cruise control block 32 via line 3 and 2C, when signal 2 is signal THB1 is sent from economy cruise control block 32 via line 3 and 2C. The signal @TH82 from the auto-cruise control block is inputted to the throttle opening control block 35 via line 33C, and when the signal is 3, the signal TH83 from the normal control block 34 is inputted to the throttle opening control block 35 via line 34b.

From the output line 31i, a set vehicle speed signal SS for auto cruise is output to the auto cruise control block 33, and from the output lines 31j and 31k, an upper limit signal VSH and a lower limit signal V of the vehicle speed for economy cruise are output.
SL is output to economy cruise control block 32. Output line 311 outputs a mode signal MOD to economy cruise control block 32. It is output to the auto cruise control block 33 and the normal running control block 34. There are three types of mode signals MOD, 1, 2, and 3, and these signals control the three control blocks 32,
Only one of 33 and 34 is selectively activated.

In addition to the signals from lines 31i and 311 mentioned above, the economy cruise control block 32 also has an input line 32
Engine speed signal NE from a and line 32b
Based on these signals, a throttle control signal T)-IBI is output from a line 32C to a throttle opening control block 35, and a clutch control signal CLB is output from a line 32d to a clutch control block 36.

Mode signal MOD to auto cruise control block 33
In addition, a vehicle speed signal vS is input via line 33a, an accelerator opening signal ACP is input via line 33b,
A throttle control signal TH82 is output from the line 33C to the throttle distance control block 35. In addition to the mode signal MOD, the line 3 is sent to the normal running control block 34.
The accelerator opening signal ACP is inputted via the line 4a, and the throttle control signal T)-183 is outputted from the line 34b to the throttle distance control block 35.

On the other hand, from the throttle opening control block 35, line 3
An operating signal is outputted to the throttle actuator 25 via line 36a to actuate the throttle valve 26, and an operating signal is outputted from the clutch control block 36 to the electromagnetic control valve 13 via line 36a to actuate the clutch actuating cylinder 11 and The clutch is actuated via a lever 12.

The control operation of the computer unit 30 configured as above will be explained with reference to the flowchart shown below.

FIG. 4A is a flowchart showing the control in the travel switching control block 31, starting from step S1, starting the 20m5 timer in step S2, and then starting the 20m5 timer.
This flow is repeated every 5 seconds, and then in step S3 it is determined whether the brake signal BR8W is ON. When this is ON, that is, when the brake is being depressed, the process proceeds to steps 818 and 819, where the set vehicle speed signal VSS, upper and lower limit signals VSH and VSL are set to zero, and the mode signal MOD and throttle opening control permission signal TH8W are set to 3. and clutch operation permission signal @CLLI
Turn off the TCH and perform normal driving control. When the brake is not operating, the process proceeds to step S4, and it is determined whether the clutch signal CLSW is ON or not. When it is ON, the process proceeds to step 818.319 to shift to normal running control, whereas when it is OFF, the process proceeds to step S5. It is determined whether the reset switch is turned on or not, and when it is turned on, flag 2 is set to zero. This reset switch is used to return the engine to economy cruise mode when the engine stops during coasting and the clutch is engaged to switch to auto cruise control.
When the flag 2 is set to zero, the economy cruise control is performed again. Then, step S
Proceed to step 7 and determine whether the cruise signal AC8W is ON or not.
When it is OFF, the process proceeds to steps 818 and 819 to shift to normal running control, and when it is ON, the process proceeds to step S8, where it is determined whether the vehicle speed is 40KJJI/H or less. Vehicle speed is 40Kj11 for both auto cruise and economy cruise.
Since this is performed only when the vehicle speed is 407 or higher than /H, if the vehicle speed is 407 or lower than /H, step 318. S
Proceed to step 19. When the vehicle speed is 40Ka/l-1 or higher, the process proceeds to step S9 to determine whether the setting signal vssw is ON, and when it is OFF, the process proceeds to step S11 to determine whether the setting signal VSS is greater than zero. . This is because the setting signal vssw is only a trigger signal, and the vehicle speed setting for constant speed driving is set when the setting signal vssw is sent.
This is because the setting signal vssw is maintained as it is even if it is turned off after that, and the setting signal vss
Even if w is OFF, constant speed driving is continued as long as a predetermined value is stored in the set vehicle speed signal SS. Therefore, when the set vehicle speed signal is zero, the process proceeds to step 818 to shift to normal running control, and when V'3S>O, the process proceeds to step 813.

On the other hand, when the setting signal vssw is ON, step 31
0, and the set vehicle speed and upper and lower limit values are set by the subroutine shown in block B. The subroutine of block B is shown in FIG. 4B, and the process proceeds from step S20 to step S21, where the smaller of the actual vehicle speed vS or 100 KJR/H is stored as the set vehicle speed signal vSS. This is to prevent the 1007 from running at a constant speed of /H or higher for safety reasons. Next, in step 822, the set vehicle speed signal v shown in FIG. 4C is
Function FNB (
VSS), a vehicle speed fluctuation range VSD suitable for this set vehicle speed signal VSS is determined. As shown in the graph of Fig. 4C, this vehicle speed fluctuation range VSD is determined when the set vehicle speed is 401 m/H or more.
When it is below 00/fz/H, the fluctuation range vS is proportional to the vehicle speed.
D is also set to be large. Furthermore, in step 823, this vehicle speed fluctuation width vSD is converted to the following distance VSD.
Correct according to the size of IS. As shown in the graph of FIG. 4D, the correction coefficient (VDIS) for this purpose is set so that when the inter-vehicle distance 11111VDrS becomes 60 m or less, the variation range vSD is also reduced in accordance with this distance. As a result, when the inter-vehicle distance is short, the range of fluctuation in vehicle speed is also reduced, and safety during driving can be improved. Next, the process proceeds to step S24, where the fluctuation range VSD obtained as described above is used as the upper limit signal VSH, which is a value obtained by multiplying the set vehicle speed signal VSS by 7Xl of this variation alVsD (VSS+V
SD) is set, and the value obtained by subtracting the fluctuation width ■SD from the set vehicle speed signal vSS is set as the lower limit signal VSL (VSS - VSD
) and ends the subroutine of block B.

Next, the process advances to step 812, where the set vehicle speed signal VSS is 4.
Check whether it is 0 fat/H or higher. If it is 40 touch/H or lower, proceed to step 818, and if it is 40&/H or higher, flag 2 is set.
Determine whether or not 1 is set. Setting flag 2 to 1 means that the engine is stopped and the clutch is engaged during coasting. At this time, the auto cruise mode is entered, so proceed to step 816 and set the mode signal MOD to 2" to set the auto cruise mode. Cruise control block 3
3, and set the throttle opening control permission signal TH8W to '2'' and also output the clutch operation permission signal @CLUTC.
)-1 is turned OFF. On the other hand, when flag 2 is not set to 1, it is determined whether the cruise method signal ECMOD is ON. This cruise method signal ECMOD is OFF
This means that auto cruise has been selected, in which case the process advances to step 816.
Auto cruise control is performed in the same manner as above, and when this signal ECMOD is ON, the process proceeds to step S15, where the mode signal MOD is set to 1' and the economy cruise control block 32 is activated, and the throttle opening control permission signal TH8W is activated. 1°° and turn on the clutch operation permission signal CLUTCH.

Step S15. When S16 or S19 is completed, the process advances to step 8817, returns to the beginning of the flow after 20 m5 has elapsed, and thereafter repeats this flow every 20 m5.

FIG. 5 is a flowchart showing the control in the auto cruise control block 33, starting from step $31, starting the 100m5 timer in step 832,
Thereafter, this flow is repeated every 100m5. Next, in step 833, it is determined whether the mode signal MOD is 2'', and only when this is 2'', the process proceeds to the next step S34.

That is, this flow does not substantially operate when the mode signal MOD is other than "2". In step S34, a value obtained by subtracting the vehicle speed signal vS from the set vehicle superstition @vss, that is, a value corresponding to the difference between the set vehicle speed and the actual vehicle speed, is set as the proportional value VS.
P, and the value obtained by subtracting the vehicle speed VLAST in the previous flow (this flow is repeated every iooms, so the vehicle speed at the time 100m5 ago) from the actual vehicle speed vs is the differential value V.
The value is stored as SD, and 1°O or -1 is stored as the integral value VS■ depending on the value of the proportional value SP.

The integral value VS[ is "1'" when the proportional value VSP is 2 or more.
', and when the proportional value vSP is 2 or less and 12 or more, "0"
When the value is -2 or less, the value becomes -1'', which causes the actual vehicle speed to become 2 from the set vehicle speed!When the vehicle is more than R/H away, it is made to approach the set vehicle speed more rapidly. There is.

Next, in step 835, predetermined coefficients Kp and K are applied to the proportional value VSP, differential value VSD, and integral value VSI, respectively.
After multiplying d and K i, the operation (VspxKp-VSD
XKd-K i ) and obtain this as the throttle opening correction value THD.

In step 336, the throttle control signal TI-(B2) is corrected using this correction value THD to obtain a throttle control signal TH82 for bringing the vehicle speed closer to the set vehicle speed. must be between fully open (opening degree 0°) and fully opening degree 80°, so in step 837, the signal T
When HB2 is 80" or more, set it to 80", and when it is below 0°, set it to 0°. Additionally, step 838
In step 839, the current vehicle speed is stored as VLAST, and in step 839, the throttle valve opening FN2 < ACP) calculated from the accelerator opening signal ACP is stored as the actual throttle distance signal TH82B. Next, in step S40, the larger one of the signal TH82 calculated in steps 834 to 837 and the actual throttle distance signal TH82B is selected as the throttle control signal Tl-lB2. This is so that when the driver depresses the accelerator pedal in an attempt to accelerate the vehicle while the vehicle is running at a constant speed, the throttle opening degree is further increased in response to the driver's depressing the accelerator pedal to accelerate the vehicle. After that, wait for 100 m5 to pass and return to the beginning of the flow, and repeat this flow every 100 m5 thereafter.

FIG. 6 is a flowchart showing the control in the economy cruise control block 32, and this flow includes step 85.
1 and in step 852 the mode memory M
Initialize ODM by zeroing it, then step 85
3, the 20m5 timer is started, and this flow is repeated every 20m5 thereafter. First, step S5
4, it is determined whether "1" is input to the mode signal MOD, and if this is outside "u", the process proceeds to steps 875 and 876, where the clutch control signal CLB is turned on and the throttle control signal TH81 is turned on. Make it zero. Note that this flow is performed when the mode signal MOD is “1”.
Therefore, it can be said that the determination in step 854 is for safety against noise and the like.

Next, in step S55, the engine speed signal N
It is determined whether or not E is smaller than the engine stall determination rotation signal NFL, and the presence or absence of engine stall is determined.

When it is smaller than the engine stall determination rotation signal NFL,
That is, when the engine is stalled, flag 1 is set to "1", and when it is greater than the NFL, that is, when it is not an engine stall, flag 1 is set to O.
8, the mode memo IJ M OD M is '1'
If there is no determination, proceed to step 859, set 1'' to the acceleration mode signal, and use the function to calculate the engine speed based on the lower limit signal VSL to obtain the lower limit vehicle speed using the gear ratio, etc. FN (VSL
), this lower limit engine speed signal NEM is determined and stored, and the process proceeds to step S60. On the other hand, mode memory M
When ODM is '1', the process directly proceeds to step 860 and the value of the mode signal MOD is stored in the mode memory MODM. However, if the setting in step S59 is performed in the first time of this flow, it will be stored in the second and subsequent times. This is because in the flow, as long as the mode memory MODM is 1, there is no need to repeat this set.

Next, the process advances to step 861 to output the acceleration mode signal ACC.
This acceleration mode signal ACC is a signal that distinguishes between a slow acceleration state and a coasting state in economy cruise.When it is "1", it is a slow acceleration state, and when it is "0", it is a slow acceleration state.
'' indicates that the vehicle is coasting. In addition, in step S59, the acceleration mode signal ACC is set to "1", which means that when the economy mode is selected, the vehicle will first be slowly accelerated to the upper limit of the set vehicle speed. This is to make them do the following.

When the acceleration mode signal ACC is 1', the process proceeds to step S62, where it is determined whether the vehicle speed signal ■S is larger than the upper limit signal VSH, and when this is smaller than VSH, that is, when the vehicle speed has not yet reached the upper limit value. is a function FN2 (VS
) to obtain a predetermined throttle control signal THBI. On the other hand, when the vehicle speed reaches the upper limit value, the vehicle speed signal ■S changes to the upper limit value signal V.
When it is greater than or equal to SH, steps 863 to 865 are performed, the throttle control signal @THBI is set to O'', and the clutch control signal CLB is set to O''.
FF, set the acceleration mode signal ACC to O'', and shift to coasting.

On the other hand, if it is determined in step S61 that the acceleration mode signal ACC is "0", that is, the vehicle is in a coasting state, the process proceeds to step 867, and it is determined whether the vehicle speed signal vS is smaller than the lower limit value signal VSL. Lower limit signal VS
If it is larger than L, the coasting state is continued and the lower limit signal ■SL,! : If it is equal to or larger than this, proceed to steps 868 to S70, input the signal α that opens the throttle opening by a predetermined amount to the throttle control signal @THB1, and set the engine speed signal N at this time.
The difference NEI between E and the lower limit engine speed signal NEM calculated in step 859 is calculated, and it is determined whether the absolute value of this difference NEI is smaller than a predetermined minute value β. Difference N
If EI is greater than β, the signal α is increased by a minimum of Δα and steps 868-870 are repeated. In other words, the throttle valve is smoothly opened until the engine rotation reaches a rotation corresponding to the lower limit value of the set vehicle speed.After this, steps 872 to 874 are performed to turn on the clutch control signal and adjust the speed to the current vehicle speed. Function FN2 to find the throttle opening necessary for slow acceleration
A predetermined throttle control signal 7rHB1 is obtained from (VS) and the acceleration mode signal is set to 1''.

After the above flow, in step S77, wait for 20 m5 to elapse, and then return to step S53, and repeat this flow every 20 m5.

FIG. 7 is a flowchart showing the control in the normal running control block 34, starting from step S90, and in step 891, it is determined whether the mode signal MOD is 3''. When the mode signal MOD is not "3", control by this flow is unnecessary, so the throttle control signal TH
83 is set to zero and this flow ends. On the other hand, when the mode signal MOD is "3", a function FN2 (throttle control signal T from ACP>) - IB3 is determined in step 893 to determine the necessary throttle control signal according to the accelerator opening signal ACP, and this flow end. FIG. 8 is a flowchart showing control in the throttle opening control block 35, starting from step 5101, starting a 20m5 timer in step 8102, and then setting the throttle opening control permission signal TH3W to "1" in steps 8103 to 8107. , "2", or "3", and if TH8W-1, the throttle control signal THBI is set to the actuator signal TH.
Store it as OBj, and for TH8W-2, THB2
is stored as the actuator signal THOBj, and TH
When 8W-3, TH83 is actuator signal THO
Store it as Bj. Next, in step 5108, the actuator signal THOBj is sent to the actuator 25.
The throttle valve 26 is controlled to open and close so that the opening degree is determined by this signal THOBj. After this, in step 5109, 20 m5 has elapsed, and the following 20 m5 have elapsed.
This flow is repeated every m5.

FIG. 9 is a flowchart showing control in the clutch 1tllllll block 36, and this flow includes step 5.
121, and in step 5122, it is determined whether the clutch operation permission signal CLLJTCH is ON, that is, whether the cruise mode is economy cruise mode. If it is not the economy cruise, the process proceeds to step 5124, where the clutch actuator 13 is turned off, the clutch is connected, and this flow ends. On the other hand, when the permission signal CLUTCI-1 is ON, the process proceeds to step $123, where it is determined whether or not the clutch control signal CLB is ON.
When it is FF, it is in a coasting state and the actuator 13 is turned ON to disengage the clutch, and when the signal CLB is ON, it is a slow acceleration state and the clutch actuator 13 is turned on.
Turn FF, connect the clutch, and end this flow.

(Effects of the Invention) As explained above, according to the present invention, when economy cruise is selected, slow acceleration and coasting are repeated within a predetermined vehicle speed range, thereby achieving constant speed driving with relatively low fuel consumption. In addition, the difference between the upper limit and lower limit increases as the set vehicle speed increases, so even if the vehicle speed fluctuation range is somewhat large, the driving feeling is less likely to be impaired at high vehicle speeds. By increasing the fluctuation range, it is possible to prevent the repetition frequency of slow acceleration and coasting from becoming too large even if the deceleration during coasting increases due to the large running resistance. When the vehicle speed is low and the vehicle speed is small, the fluctuation range can be reduced to reduce the influence on the driving feeling due to vehicle speed fluctuations.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the overall configuration of a cruise control device according to the present invention; FIG. 2 is a graph showing changes over time in vehicle speed, engine rotation, etc. when the cruise control device performs cruise control; FIG. 3 4A, 4B, and 5 to 9 are flowcharts showing the control contents of each control block of the computer unit; The figure shows the travel switching control block.
Figure 4B shows the subroutine "Block B" in Figure 4A, Figure 5 shows the auto cruise control block, Figure 6 shows the economy cruise control block, Figure 7 shows the normal running &!I l block, and Figure 8 shows the throttle opening. The control block, FIG. 9 shows the control by the clutch control block, FIG. 4C is a graph showing the vehicle speed variation range with respect to the set vehicle speed, and FIG. 4D is a graph showing the correction coefficient of the vehicle speed variation range with respect to the inter-vehicle distance.1 ... Brake pedal 3 ... Accelerator pedal 1
0...Clutch 11...Clutch operation cylinder 13...Solenoid control valve 16...Vehicle speed sensor 22
... Water temperature sensor 25 ... Throttle actuator 26 ... Throttle valve 30 ... Computer unit Fig. 2 Fig. 4c

Claims (1)

[Scope of Claims] A driving control device that controls the amount of fuel supplied to an engine based on a set vehicle speed signal input from the outside, and maintains the vehicle speed within a certain range around the set vehicle speed to perform constant speed driving. a constant speed driving condition detecting means for detecting whether or not a constant speed driving condition occurs; upper and lower limit vehicle speed setting means for setting an upper and lower limit value of vehicle speed within the range; and a slow acceleration device for performing slow acceleration driving by controlling the amount of fuel supplied to the engine until the vehicle speed reaches the upper limit value from the lower limit value. and a coasting means that cuts off the transmission of driving force from the engine to the wheels when the vehicle speed reaches the upper limit value and causes the vehicle to coast until the vehicle speed reaches the lower limit value; A driving control device for a vehicle, characterized in that the difference between the upper limit value and the lower limit value set by a setting means increases as the set vehicle speed increases.