JPH054250B2 - - Google Patents

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 after that, this set vehicle speed and the actual vehicle speed are In comparison, 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 period the engine speed is reduced to idling. By doing so, constant speed driving control with good fuel efficiency can be performed. For this reason, for example,
Publication No. 22113 discloses a vehicle running control that determines a predetermined speed range based on the set vehicle speed when a constant speed running condition occurs, and repeats slow acceleration and coasting between the upper and lower limit values in this range. A method and apparatus are proposed. For convenience of explanation, the conventional constant-speed driving in which the engine throttle opening (or fuel injection amount) is controlled to maintain the vehicle speed within a certain range will be referred to as autocruise, and the above proposal will be referred to as autocruise. Constant-speed driving in which the vehicle speed is maintained within a predetermined range by repeating slow acceleration and coasting is called economy cruise.

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. When the vehicle speed reaches the lower limit, the engine rotation is increased to the rotation corresponding to the vehicle speed, and then The clutch is engaged and the engine speed is gradually increased to perform gentle acceleration until the vehicle speed reaches the upper limit. For example, if the engine temperature is low and the response of the engine speed to the throttle opening/closing operation is not good, When the vehicle speed reaches the lower limit while coasting, it takes time to open the throttle and increase the engine speed to a level corresponding to the vehicle speed, and during this time the vehicle speed falls below the lower limit. There is a problem. The same thing happens when driving uphill. In other words, since running resistance is large on uphill slopes, the deceleration of vehicle speed is large. Therefore, when the vehicle speed reaches the lower limit, even if you try to increase the engine rotation to the rotation corresponding to the vehicle speed, the vehicle speed will be decelerated during this time. There is a problem in that the value falls below the lower limit. Furthermore, if the vehicle speed reaches the upper limit while traveling downhill, the opposite phenomenon may occur.

In addition, above we have described the problems in the case of economy cruise, but even in the case of auto cruise, control is performed to maintain the vehicle speed within a predetermined range, and when the engine temperature is low and responsiveness is not good, Similar to the above, there is a problem in that the vehicle speed fluctuates beyond a predetermined range. In other words, in both economy cruise and auto cruise, in the above cases, even when driving at a constant speed, the actual speed may vary depending on the engine temperature, driving conditions, etc. There is a problem in that the vehicle speed of the vehicle fluctuates beyond these upper and lower limits (that is, the vehicle speed fluctuates greatly when traveling at a constant speed).

(Object of the Invention) In view of these problems, the present invention always maintains the vehicle speed while driving at a constant speed, regardless of engine operating conditions (engine temperature, etc.) and driving conditions (whether driving on a slope, etc.). It is an object of the present invention to provide a travel control device that can maintain a constant range of fluctuation in vehicle speed by maintaining it within a certain range.

(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 output of the engine to perform constant speed driving. When detecting whether or not a driving condition exists and causing constant speed driving when a constant speed driving condition exists,
The upper and lower limit vehicle speed setting means sets the upper and lower limits of the control vehicle speed range for driving at a constant speed within the vehicle speed range based on the set vehicle speed, and decelerates when the vehicle speed exceeds the upper limit. At the same time, when the vehicle speed falls below the lower limit value, the vehicle speed is increased.Meanwhile, the state detection means detects the engine operating state such as the engine temperature, or detects the driving state such as whether or not the vehicle is running on a slope. The present invention is characterized in that at least one of the upper limit value and the lower limit value is corrected depending on the engine operating state or the running state.

(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. The computer unit 30 is controlled by turning the cruise control switch 30a on and off, and 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 an accelerator signal. A signal from an accelerator pedal position sensor 4 that detects the amount of depression of the accelerator pedal 3 in conjunction with the pedal 3; a signal from an engine stop detection sensor 21 that detects whether or not the engine 20 has stopped in the distributor; a signal from a water temperature sensor 22 that detects the cooling water temperature;
The vehicle speed is detected based on a signal from the throttle position sensor 23 that detects the opening of the throttle valve 26, a signal from the intake air temperature sensor 24 that detects the intake air temperature, and the rotation of the power transmission system on the output side of the clutch 10. Signals from the vehicle speed sensor 16 are input, and the throttle actuator 25 and the electromagnetic control valve 1 are activated based on these input signals.
Outputs an activation signal to 3. The electromagnetic control valve 13 controls the hydraulic pressure supply to the clutch actuating cylinder 11 to control the engagement and disengagement of 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 1 is engaged via the lever 12.
It is designed to cause intermittent 0's.

FIG. 2 is a graph showing changes over time in vehicle speed, engine rotation, etc. when the travel control device performs travel control. This graph shows changes when the cruise control switch 30a is turned on at time A, and shows the change in vehicle speed V at this time.
, the upper limit of the vehicle speed range (V
+△v) and lower limit value (V-△v) are determined,
First, from this state, the engine throttle opening degree is gradually increased and gradual acceleration is performed until the vehicle speed reaches the upper limit value (v+ΔV). When the vehicle speed reaches the upper limit (point B), the clutch 10 is turned off, the throttle opening is fully closed, the engine rotation is reduced to idling rotation, and the vehicle is allowed to coast 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 - △V) (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 degree is gradually increased again, and gradual acceleration is performed until the vehicle speed reaches the upper limit value. In the present invention, the value of ΔV is corrected depending on engine operating conditions such as engine temperature and vehicle running conditions.

FIG. 3 is a block diagram showing the configuration of the computer unit 30. The computer unit 30 includes a travel switching control block 31, an economy cruise control block 32, and an auto cruise control block 3.
3. Normal running control block 34, throttle opening control block 35 and clutch control block 3
Consists of 6.

The travel switching control block 31 has an input line 31.
a to 31f and output lines 31g to 31k are connected. The input line 31a receives the brake signal BRSW from the brake switch 2, the input line 31b receives the clutch signal CLSW from the clutch switch that detects clutch operation, and the input line 31c receives the cruise signal ACSW from the craze switch. From line 31d is the cruise method signal ECMOD from the cruise method switch.
However, the setting signal VSSW from the vehicle speed set switch is input from the input line 31e, and the vehicle speed signal VS from the vehicle speed sensor 16 is input from the input line 31f. The cruise switch is a switch that switches between normal driving and constant speed driving, and the craze method switch is a switch that switches between normal driving and constant speed driving, and when constant speed driving is selected, the craze method switch switches between conventional constant speed driving (auto cruise) and slow acceleration and coasting according to the present invention. The vehicle speed set switch is a switch for setting the vehicle speed for constant speed travel (economy cruise), which repeats the above, and constitutes the cruise control switch 30a in FIG. 1.

The output line 31g outputs a clutch operation permission signal CLUTCH to the clutch control block 36, and the output line 31h outputs a throttle opening control permission signal to the throttle opening control block 35.
Output THSW. Clutch operation permission signal
CLUTCH is an ON/OFF signal, and 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 THSW: 1, 2, and 3. When the signal is 1, the signal is sent from the economy cruise control block 32 via the line 32c.
THB1 and signal THB from the auto cruise control block via line 33c when signal 2.
2, and when the signal is 3, the signal THB3 from the normal control block 34 is input to the throttle opening control block 35 via the line 34b.

From the output line 31i, a set vehicle speed signal VSS for auto cruise is output to the auto cruise control block 33, and output lines 31j and 31
From k, an upper limit signal VSH and a lower limit signal VSL of vehicle speed for economy cruise are output to the economy cruise control block 32. A mode signal MOD is output from the output line 31l to the economy cruise control block 32, auto cruise control block 33 and normal cruise control block 34. There are three types of mode signals MOD, 1, 2, and 3, and these signals selectively operate only one of the three control blocks 32, 33, and 34.

In addition to the signals from the lines 31i and 31l, the economy cruise control block 32 receives an engine speed signal NE from the input line 32a.
and the vehicle speed signal VS from the line 32b are input, and based on these, a throttle control signal is sent from the line 32c to the throttle opening control block 35.
THB1 outputs a clutch control signal CLB to clutch control block 36 from line 32d.

In addition to the mode signal MOD, a vehicle speed signal VS is input to the auto cruise control block 33 via a line 33a, an accelerator opening signal ACP is input via a line 33b, and a throttle opening control block 35 is input from a line 33c for throttle control. signal
THB2 is output. Normal running control block 3
4 to line 34a in addition to the mode signal MOD.
The accelerator opening signal ACP is input through the line 34b to the throttle opening control block 35.
A throttle control signal THB3 is output.

On the other hand, the throttle opening control block 35 outputs an operating signal to the throttle actuator 25 via a line 35a to operate the throttle valve 26, and the clutch control block 36 outputs an electromagnetic control signal via a line 36a. An actuation signal is output to the valve 13 to actuate the clutch via the clutch actuation cylinder 11 and lever 12.

Computer unit 3 configured as above
The control operation of 0 will be explained using the flowchart shown below.

FIG. 4 is a flowchart showing the control in the travel switching control block 31, starting from step S1, starting a 20 mS timer in step S2, repeating this flow every 20 mS, and then turning on the brake signal in step S3.
Determine whether BRSW is ON. When this is ON, that is, when the brake is being depressed, the process advances to steps S18 and S19, sets the vehicle speed signal VSS, upper and lower limit signals VSH and VSL to zero, and sets the mode signal MOD and throttle opening control permission signal.
Set THSW to 3, clutch operation permission signal
Turn CLUTCH OFF and perform normal driving control. When the brake is not working, step
Proceeding to S4, it is determined whether the clutch signal CLSW is ON or not. If it is ON, the process proceeds to steps S18 and S19 to shift to normal running control. Next, the process proceeds to step S7, where it is determined whether the cruise signal ACSW is ON or not.
When it is OFF, the process proceeds to steps S18 and S19 to shift to normal driving control, and when it is ON, the process proceeds to step S8 to determine whether the vehicle speed is 40 km/h or less. Vehicle speed is 40 for both auto cruise and economy cruise.
Since this is done only when the vehicle speed is above 40km/h, the step is not performed when the vehicle speed is below 40km/h.
Proceed to S18 and S19. When the vehicle speed is 40 km/h or more, the process proceeds to step S9 to determine whether the setting signal VSSW is ON or not; when it is OFF, the process proceeds to step S11 to determine whether the set vehicle speed signal VSS is greater than zero.
This is because the setting signal VSSW is only a trigger signal.
If the vehicle speed setting for constant speed driving is set when the setting signal VSSW is sent, from then on, the setting signal VSSW
This is because it is designed to remain as it is even if the set signal VSSW is turned OFF, and constant speed driving continues as long as the predetermined value is stored in the set vehicle speed signal VSS even if the set signal VSSW is OFF. . Therefore, when the set vehicle speed signal is zero, the step
The program advances to step S18 to shift to normal running control, and when VSS>0, the program advances to step S13.

On the other hand, when the setting signal VSSW is ON, the process advances to step S10, and the actual vehicle speed is set as the setting vehicle speed signal VSS.
Store either VS or 100Km/H, whichever is smaller (this is to prevent constant speed driving over 100Km/H for safety reasons), and use this set vehicle speed signal VSS as the upper limit signal. 5Km/
The value obtained by adding H is memorized, and the value obtained by subtracting 5 km/H from the set vehicle speed signal VSS or 40 is used as the lower limit signal.
Memorize the larger of Km/H (this is
This is because running at a constant speed of 40 km/h or less is not desirable from a stability standpoint). Then set vehicle speed signal VSS
It is confirmed whether or not the speed is 40Km/H or more, and if it is less than 40Km/H, the process advances to step S18. On the other hand, when the speed is 40 km/h or more, it is determined whether the cruise method signal ECMOD is ON. This cruise method signal ECMOD
OFF means that auto cruise is selected. In this case, proceed to step S16, set the mode signal MOD to "2", activate the auto cruise control block 33, and set the throttle opening control permission signal THSW. Set it to "2" and turn off the clutch operation permission signal CLUTCH to perform auto cruise control. this signal
If ECMOD is ON, proceed to step S15,
The mode signal MOD is set to "1" to activate the economy cruise control block 32, and the throttle opening control permission signal THSW is set to "1".
Turn on the clutch operation permission signal CLUTCH.

When step S15, S16, or S19 is completed, the process advances to step SS17, returns to the beginning of the flow after 20 mS, and repeats this flow every 20 mS thereafter.

FIG. 5 is a flowchart showing the control in the auto cruise control block 33, in which step S31
Starting from , a 100 mS timer is activated in step S32, and thereafter this flow is repeated every 100 mS. Next, in step S33, it is determined whether the mode signal MOD is "2" or not, and only when it is "2", the process advances 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, the value obtained by subtracting the vehicle speed signal VS from the set vehicle speed signal VSS,
In other words, the value corresponding to the difference between the set vehicle speed and the actual vehicle speed is stored as a proportional value VSP, and the vehicle speed VSLAST in the previous flow (this flow is repeated every 100 mS, so the vehicle speed at the time 100 mS ago) is subtracted from the actual vehicle speed VS. The value is stored as the differential value VSD, and the proportional value
Integral value of 1, 0 or -1 depending on the value of VSP
Store as VSI. Integral value VSI is proportional value VSP
When the proportional value VSP is 2 or more, it is "1", when the proportional value VSP is 2 or less and -2 or more, it is "0", and when it is -2 or less, it is "-1". This value sets the actual vehicle speed. When the vehicle is more than 2 km/h away from the vehicle speed, the vehicle speed is made to approach the set vehicle speed more rapidly.

Next, in step S35, the above proportional value is
After multiplying VSP, differential value VSD, and integral value VSI by predetermined coefficients Kp, Kd, and Ki, respectively, calculate (VSP ×
Kp - VSD x Kd - VSIXKi) and find this as the throttle opening correction value THD. In step S36, the throttle control signal THB2 is corrected using this correction value THD, and the throttle control signal THB2 is used to bring the vehicle speed closer to the set vehicle speed.
get. Furthermore, this control signal THB2 changes the throttle opening from fully closed (opening 0°) to fully open (opening 80°).
Therefore, in step S37, if the signal THB2 is 80° or more, it is set to 80°.
When the temperature is below 0°, set this to 0°. moreover,
In step S38, the current vehicle speed is stored as VSLAST, and in step S39, the throttle valve opening calculated from the accelerator opening signal ACP is stored.
FN2 (ACP) is the actual throttle opening signal THB2B
be memorized as Next, in step S40, the throttle control signal THB2 is set as the throttle control signal THB2.
The larger one of the signal THB2 calculated in S37 and the actual throttle opening signal THB2B is selected. This is so that when the driver presses the accelerator pedal in an attempt to accelerate the vehicle while driving at a constant speed, the throttle opening is further increased in response to this, allowing the vehicle to accelerate. After this,
Wait for 100 mS to elapse, return to the beginning of the flow, and repeat this flow every 100 mS thereafter.

Figure 6 shows the economy cruise control block 32.
This flowchart starts from step S51, initializes the mode memory MODM by zeroing it in step S52, starts the 20mS timer in step S53, and repeats this flow every 20mS thereafter. Do it like this. First, in step S54, it is determined whether "1" is input to the mode signal MOD, and if this is other than "1", step S67 is performed.
Proceed to S68 and turn on the clutch control signal CLB.
Set the throttle control signal THB1 to zero. In addition,
Since this flow is performed when the mode signal MOD is "1", it can be said that the determination in step S54 is for safety against noise and the like.

Next, in step S58, the mode memory is
Determine whether MODM is "1" or not, and if it is not "1", proceed to step S59, set "1" to the acceleration mode signal, and set the engine speed to the gear to obtain the vehicle speed lower limit based on the lower limit value signal VSL. This lower limit engine speed signal NEM is obtained from the function FN (VSL) calculated by a ratio, etc., this is stored, and the process proceeds to step S60. On the other hand, when the mode memory MODM is "1", the process directly advances to step S60, and the value of the mode signal MOD is stored in the mode memory MODM. This is because in the second and subsequent flows, it is not necessary to repeat this setting as long as the mode memory MODM is 1.

Next, proceed to step S61 to output the acceleration mode signal.
Determine whether ACC is "1" or not. This acceleration mode signal ACC is a signal that distinguishes between a slow acceleration state and a coasting state in economy cruise, and is set to "1".
When it is "0", it is in a state of slow acceleration, and when it is "0", it is in a coasting state. The acceleration mode signal ACC is set to "1" in step S59, because when the economy mode is selected, slow acceleration is first performed up to the upper limit of the set vehicle speed.

When the acceleration mode signal ACC is "1", the process proceeds to step S62, where it is determined whether the vehicle speed signal VS is larger than the upper limit value signal VSH, and when this is smaller than VSH, that is, when the vehicle speed has not yet reached the upper limit value. calculates a predetermined throttle control signal THB1 from a function FN2 (VS) that determines the throttle opening required to perform gentle acceleration for the current vehicle speed from the relationship between the vehicle speed and the throttle opening. On the other hand, when the vehicle speed reaches the upper limit value, the vehicle speed signal VS changes to the upper limit value signal VSH.
When the value is greater than or equal to this, steps S63 to S65 are performed, the throttle control signal THB1 is set to "0", the clutch control signal CLB is set to OFF, and the acceleration mode signal ACC is set to "O".
and shift to coasting.

Meanwhile, in step S61, the acceleration mode signal is
If it is determined that ACC is "0", that is, the vehicle is in a coasting state, the process advances to step S70 and subroutine A is executed. FIG. 7 is a flowchart showing the subroutine A of step S70. Here, after entering step S71, in step S72, the vehicle speed signal VS and the memory vehicle speed signal VSM stored when this routine was operated last time are input. The difference between
In other words, the rate of change in vehicle speed DVS is calculated. Then,
In step S73, it is determined whether this rate of change DVS is negative or not, that is, whether the vehicle speed is decreasing or not. If this is positive or zero (vehicle speed increases or remains the same), it is determined whether coasting is continued as it is. OK, so proceed to step S84. On the other hand, the rate of change
When DVS is negative, in step S74, the lower limit value is calculated from the function FNC (Fig. 8A) corresponding to this rate of change DVS.
Find the VSL correction coefficient KVS. Note that in this flow, the correction coefficient KVS is determined according to the magnitude of the vehicle speed change rate DVS, but instead of this, the
As shown in Figure B, it may be determined according to the engine water temperature or according to the gradient of the slope.

Next, in step S75, this correction coefficient KVS
The lower limit signal VSL is corrected, and this corrected value is compared with the vehicle speed signal, and if the vehicle speed signal VS is larger than the correction value (VSL×KVS), the process proceeds to step S84 to continue coasting. vehicle speed signal
If VS is smaller than the correction value, the process advances to step S76 and the engine rotation corresponding to the corrected lower limit value signal is adjusted.
After opening the throttle to increase the engine speed to NEM and waiting in step S77 until the actual engine speed signal NE reaches NEM,
Proceed to step S78 to set the clutch control signal CLB.
Turn on and connect the clutch. Next, in order to proceed to slow acceleration, the throttle opening THBB necessary for slow acceleration from the vehicle speed VSL is determined in step S79.
In steps S80 to S83, the throttle opening is increased by increasing the throttle opening by △ every 20mS.
Gradually open to THBB. After the above flow, the current vehicle speed signal VS is stored as a memory vehicle speed signal VSM in step S84, the process proceeds to step S85, this subroutine A is ended, and the process returns to the flow shown in FIG. 6 and proceeds to step S69.

After the above flow, 20m is reached in step S69.
After the passage of S, return to S53 and continue for 20 mS.
Repeat this flow every time.

FIG. 9 is a flowchart showing the control in the normal running control block 34, starting from step S90, and at step S91, the mode signal is
Determine whether MOD is “3” or not. mode signal
When MOD is not "3", control according to this flow is unnecessary, so the throttle control signal THB3 is set to zero and this flow is ended. On the other hand, the mode signal
When MOD is "3", the throttle control signal THB3 is obtained from the function FN2 (ACP) for obtaining a necessary throttle control signal according to the accelerator opening signal ACP in step S93, and this flow is ended.

FIG. 10 shows the throttle opening control block 35.
A flowchart showing the control in the step
Starting from S101, 20mS at step S102
Start the timer, then steps S103 to S107
, it is determined whether the throttle opening control permission signal THSW is "1", "2", or "3", and when THSW=1, the throttle control signal THB1 is stored as the actuator signal THOBj, and THSW=2. In this case, THB2 is stored as the actuator signal THOBj, and THSW=3.
In this case, THB3 is stored as the actuator signal THOBj. Next, in step S108, actuator signal THOBj is applied to actuator 2.
5, and controls the opening and closing of the throttle valve 26 so that the opening degree is determined by this signal THOBj.
After this, 20 mS elapses in step S109, and this flow is repeated every 20 mS thereafter.

FIG. 11 is a flowchart showing the control in the clutch control block 36. This flow starts at step S121, and in step S122 it is determined whether the clutch operation permission signal CLUTCH is ON or not, that is, whether or not it is economy cruise. If it is not an economy cruise, the process proceeds to step S123, where the clutch actuator 13 is turned off to connect the clutch, and this flow ends. On the other hand, when the permission signal CLUTCH is ON, the process proceeds to step S124, where it is determined whether the clutch control signal CLB is ON or not. When this signal CLB is OFF, it is in a coasting state, and the actuator 13 is turned ON to disengage the clutch. , when the signal CLB is ON, it is in a slow acceleration state and the clutch actuator 13 is activated.
Turn it off and connect the clutch.

Although this embodiment shows an example in which only the lower limit value is corrected, it goes without saying that the upper limit value may also be corrected.

Furthermore, although this embodiment has been described with reference to economy cruise, in auto cruise, there is no control to cause coasting, and other similar controls may be performed.

(Effects of the Invention) As explained above, according to the present invention, when driving at a constant speed, upper and lower limits of the control vehicle speed range for driving at a constant speed are set based on a set vehicle speed, and At least one of the upper and lower limits is corrected depending on the engine operating condition or the vehicle driving condition, so when the engine temperature is low and engine response is poor, or when driving uphill (downhill). Even in cases such as when the deceleration (acceleration) of the vehicle is large, the actual vehicle speed can always be maintained within a predetermined range by correcting the upper or lower limit value, which prevents hunting near the set vehicle speed. This can be prevented and constant speed running performance is improved.

[Brief explanation of drawings]

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, and FIG. The figure is a block diagram showing the configuration of a computer unit used in the above-mentioned travel control device, and Figs. 4 to 7 and Figs. 9 to 11 are flowcharts showing the control contents of each control block of the above-mentioned computer unit. Figure 4 is a cruise switching control block diagram, Figure 5 is an auto cruise control block, Figure 6 is an economy cruise control block, Figure 9 is a normal cruise control block, Figure 10 is a throttle opening control block, and Figure 11 is a diagram of a throttle opening control block. shows the control in the clutch control block,
FIG. 7 is a flowchart showing the control in subroutine A of FIG. 6, and FIGS. 8A and 8B are graphs showing the modification coefficient of the lower limit signal with respect to the vehicle speed change rate and engine water temperature, respectively. 1...brake pedal, 3...accelerator pedal, 10...clutch, 11...clutch operation cylinder, 13...electromagnetic control valve, 16...vehicle speed sensor, 22...water temperature sensor, 25...throttle actuator Eta, 26... Throttle valve, 30
...computer unit.

Claims (1)

[Scope of Claims] 1. A driving control device that controls the output of the engine based on a set vehicle speed signal inputted from the outside, maintains the vehicle speed within a certain range around the set vehicle speed, and makes the vehicle run at a constant speed. In the vehicle, constant speed driving condition detection means detects whether or not a constant speed driving condition is occurring; upper and lower vehicle speed limit setting means for setting an upper limit value for decelerating the vehicle when the vehicle speed exceeds the speed limit and a lower limit value for increasing the speed when the vehicle speed falls below the speed limit for driving the engine; a state detection means for detecting a state or a running state of the vehicle; and an upper limit value or a lower limit value that is set by the upper and lower limit vehicle speed setting means in response to the output of the state detection means and according to the operating state of the engine or the running state of the vehicle. What is claimed is: 1. A vehicle running control device comprising: a correction means for correcting at least one of the following. 2. The vehicle running control device according to claim 1, wherein the state detection means is a means for detecting engine temperature. 3. The correcting means is a means for receiving the engine temperature detected by the state detecting means and correcting the lower limit value to be larger when the engine temperature is low. 2. The vehicle travel control device according to item 2. 4. Claim 1, wherein the state detection means is a means for detecting whether the vehicle is traveling uphill or downhill. A travel control device for a vehicle as described in Section 1. 5. A patent characterized in that the state detection means is means for detecting deceleration of the vehicle, and when the detected deceleration is larger than a predetermined value, the correction means makes a correction to increase the lower limit value. A vehicle running control device according to claim 1.