JPH0277334A - Constant speed running control method for vehicle - Google Patents

Abstract

PURPOSE:To prevent to repeat the gear shift operation of a gear shift device frequently by converting the value of the object gear position to a lower gear position when the constant speed running at a preset object car speed is made impossible, moreover, making the value of the object car speed into a lower car speed once, and carrying out a shift-up only when it is made possible to shift up the gear shift device under such a condition. CONSTITUTION:When an excessive torque of the engine is lost, or an engine failure condition is generated, the value of a temporary object gear position signal S1 is made into the sixth or the fifth speed position in the discrimination by the signal from a running allowance discriminator 36, and responding to that, the gear shift operation is started by a gear shift control device. In this case, a switch 35 is converted to the dotted line side instantly, and the temporary object car speed data Db is given to a cruise Q operation unit 43. The value of the temporary car speed data Db is the preset value to make it possible to run at a constant speed responding to the actual gear position at that time. And after that, a switch 49 is shifted responding to the operation output data Tr output at the time when an excessive torque operation unit 42 judges that there is an excessive torque, the first instruction unit 48 outputs the data D to indicate the sixth speed, and the gear shift is carried out to the sixth speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a constant speed running control method for a vehicle, which automatically performs driving operations of the vehicle so that the vehicle speed is maintained at a required set value. It is something.

(Prior Art) Conventionally, in order to maintain the vehicle speed of an internal combustion engine vehicle equipped with an automatic transmission at a predetermined set vehicle speed, for example, the throttle opening is adjusted according to the detection result of the actual vehicle speed. If the required vehicle speed cannot be achieved even if the engine is put into a high output state due to the increase in output, shift down the transmission gear to
A constant speed traveling device for a vehicle is known that is configured to be able to achieve a required vehicle speed by making the vehicle perform the following steps.

By the way, this conventional device is generally configured to perform an upshift operation at the maximum vehicle speed when the set vehicle speed is higher than the maximum vehicle speed of the downshifted gear. However, when the engine load is still high, such as when driving on a hill, the gear must be downshifted again, which causes the problem that the gearshift operation is performed frequently and the ride comfort is significantly impaired. Was.

As one means to solve this problem, a constant speed driving control is implemented in which a predetermined target vehicle speed range is determined based on a signal indicating a desired set vehicle speed, and the actual vehicle speed is maintained within this target vehicle speed range. A means is provided to execute a gear shift down operation when the actual vehicle speed decreases beyond the lower limit of the target vehicle speed range, and after the vehicle speed returns to the lower limit and a gear shift is performed, A constant speed traveling device has been proposed that changes the set vehicle speed so that the difference from the lower limit value is reduced, thereby avoiding repeated and frequent gear shift operations (% open speed). Publication No. 105726/1982].

(Problem to be Solved by the Invention) However, in the conventional device proposed above, the target vehicle speed changes within a predetermined range determined based on the set vehicle speed for constant speed cruise control, and furthermore, the target vehicle speed is Since the vehicle speed is determined regardless of the driver's will, the desired vehicle speed set by the driver cannot be reliably maintained, which poses a problem in terms of operability.

An object of the present invention is to prevent the gear shift operation of the transmission from being carried out frequently and to achieve the desired set vehicle speed set by the driver even under driving conditions where the engine load fluctuates rapidly. An object of the present invention is to provide a constant speed running control method for nine vehicles.

(Means for Solving Problem 8) The method of the present invention for achieving the above object is characterized by a method for controlling the vehicle speed of an internal combustion engine vehicle equipped with an automatic transmission so as to maintain the vehicle speed at a predetermined set vehicle speed. In the constant speed running control method for a vehicle, when the predetermined set vehicle speed cannot be maintained, the content of the target gear position given to the automatic transmission is changed to content indicating a lower gear position, and the above setting is performed. The content of the vehicle speed is changed to content indicating a lower vehicle speed, and in the control state obtained as a result, the 7 of the transmission
Determines whether or not shifting is possible, and when it is determined that upshifting of the transmission is possible, causes the transmission to perform an upshift operation, and the content of the set vehicle speed is returned to the original content before the change. The point is that I changed it back to .

(Function) During constant speed driving in a predetermined gear position, for example, the upper IXK
When it becomes impossible to maintain the given target vehicle speed for some reason, the transmission is operated to downshift, and at the same time, a temporary target vehicle speed is set to a lower vehicle speed than the previous target vehicle speed. The temporary target value is, for example, the maximum speed in that gear. As a result, the vehicle is shifted to a gear position lower than the original gear position, and the vehicle speed is controlled here so that the vehicle speed matches the tentative target vehicle speed.

During this time, it is determined whether an upshift is possible, for example by checking the engine's spare torque. If it is determined that an upshift is possible, the transmission is shifted 77 to an appropriate gear position, and the target vehicle speed is changed from the temporary target vehicle speed to the original target vehicle speed. As a result, a predetermined constant speed running state is achieved.

(Example) Hereinafter, the method of the present invention will be explained in detail with reference to the illustrated example.

FIG. 1 shows an embodiment of a vehicle width control device which performs constant speed driving control of a vehicle by the method of the present invention and is equipped with nine vehicle constant speed driving control devices.

In the internal combustion engine vehicle 1 shown in FIG.
an automatic transmission control system 10 configured to transmit transmission to the internal combustion engine 2, and comprising a clutch actuator 8 provided in the clutch 3 and a transmission actuator 9 provided in the transmission 5; A constant-speed cruise control system 12 adjusts the throttle so that the vehicle speed is maintained at a desired set vehicle speed by a throttle actuator 11 (not shown) for opening and closing the throttle, thereby causing the vehicle to travel at a constant speed. We are prepared. Constant speed running control system 12
As will be described in detail later, the automatic transmission control system 10 cooperates with the automatic transmission control system 10 to achieve its required functions.

First, regarding the automatic transmission control system 10, the piston rod 81 of the clutch actuator 8 is connected to the release lever 31 of the clutch 3 provided on the flywheel 2a.
is connected to. The clutch actuator 8 has a clutch ON pulp vN for moving the pressure grate 3b operated by the release lever 3alC in the direction in which the clutch 3 is in the connected state, and a clutch ON pulp vN for moving the pressure grate 3b in the direction in which the clutch 3 is in the disengaged state. It is equipped with a clutch OFF'pulp V for moving the pulp. When the clutch ON pulp vN is opened in response to an externally applied electrical signal, the clutch actuator 8 operates to connect the clutch 3, while the clutch O
When the FF pulp vF is opened in response to an externally applied electric signal, the clutch actuator 8 operates to disengage the clutch 3.

A stroke sensor 13 is provided to detect the position of the pressure grate 3b operated as described above by the clutch actuator 8, and from the stroke sensor 13, a clutch sensor 13 indicating the current position of the pressure grate 3b is provided. A signal CL is output.

The clutch signal CL is given to a clutch control device 15 to which a clutch on/off signal V is input from a shift control device 14, which will be described later.

In response to the clutch on/off signal NF, the clutch control device 15 sends a first command signal M1 for disengaging (turning off) the clutch 3, and a brake clutch fv-) 3b in the connecting (on) direction of the clutch 3. second command signal M to send to
A third command signal M is output for sending the pressure gray (2) and pressure gray (3b) in the OFF direction to disconnect the clutch 3, and each of these command signals M, to M3 is output to the drive circuit, 1
6 is input.

The drive circuit 16 also receives a clutch signal CL as a feedback signal, and receives each command signal M, to M.
, the first . Second drive signal ■1. Output vD2. The first drive signal VD is the clutch ON pulp v
This is a signal for controlling the opening and closing of N. Clutch ON tZ
loop vN. The second drive signal vD2 is a signal for controlling the opening and closing of the clutch OFF pulp v2, and is applied to the clutch OFF pulp V. In the illustrated embodiment, the first and second drive signals VD, , VO2
In both cases, the corresponding pulp is opened when the level is "1", and the corresponding pulp is closed when the level is rOJ.

Therefore, when the level of the first drive signal VD outputted from the drive circuit 16 becomes "1", the clutch ON valve VN (pressure gray) 3b is moved in the direction of connecting the clutch 3.

On the other hand, when the level of the second drive signal vD2 becomes "1",
The clutch OFF pulp vF is opened, and the pressure gray) 3b is moved in the direction of disengaging the clutch 3.

The shift control device 14 receives an accelerator signal A1 which is output from an accelerator pedal 18 that detects the amount of operation of the accelerator pedal 17 and indicates the accelerator operation lid at that time. The vehicle speed signal vS, which is output as a signal, and the actual gear position signal GPf, which is output from the gear position sensor 20 and indicates the actual gear position of the transmission 5, are received. The target gear position calculation unit 21 responds to the accelerator signal A and the vehicle speed signal VS, calculates the optimum gear position that matches the driving conditions of the internal combustion engine vehicle at the time, and sends a signal indicating the calculation result to the transmission 5. It is output as a target gear position signal GT indicating the target gear shift position at . The target gear position signal GT is given to the speed change control device 14 via the switch 22.

The shift control device 14 compares the target shift position indicated by the signal given from the switch 22 with the actual gear position at that time indicated by the actual gear position signal GP, and determines whether the actual gear position matches the target gear position. If there is no
Executes control for necessary gear shift operations to match the actual gear position with the target gear position. To explain the control for this gear shift operation, first, a gear change signal G/C of "1" level indicating that the control for gear shift operation is being executed is output at the same time as the control starts, and the accelerator Next, the content of the clutch on/off signal NF becomes a command to disengage the clutch 3, and the clutch actuator 8 operates in accordance with this, and the clutch 3 be separated.

A rotation setting signal Nt indicating a set value of the rotation speed of the internal combustion engine 2 when the clutch 3 is disengaged is input from the speed change control device 14 to the engine control unit 23.

When the level of gear change signal G/C is rlJ,
The speed of the internal combustion engine 2 is controlled by the engine control unit 23 to be maintained at the required rotation speed indicated by the rotation setting signal Nt by isochronous control, regardless of the operation amount of the accelerator pedal 17. .

Note that the gear change operation is not performed and the gear change signal a
/c level is rOJ, engine control unit)2
3 controls the amount of fuel supplied to the internal combustion engine 2 according to the operation amount of the accelerator pedal 17 or according to the fuel supply amount signal Q from the cruise control section 24, which will be described later, and thereby controls the engine speed. It is done. What is indicated by the code 25 is
A speed sensor for detecting the speed of the internal combustion engine 2,
A speed signal NE indicating the engine speed output from the speed sensor 25 is input to the engine control unit 23 as a feedback signal for controlling the engine speed.

While the shift control device 14 is performing the disengagement operation of the shift latch 3 and controlling the engine speed, the shift control device 1
4 further outputs a shift control signal GC, and the transmission actuator 9 shifts the gear of the transmission 5 to a required target gear position in response to the shift control signal GC. As a result, when the target gear position and the actual gear position match, the transmission control device 14 makes the command content of the clutch on/off signal NF a clutch connection operation, and as a result, the clutch 3 is connected by the clutch actuator 8. Ru. Almost at the same time, the level of the gear change signal G/C becomes rOJ, and the speed of the internal combustion engine 2 is controlled according to the operation amount of the accelerator pedal 17 or the fuel supply amount signal Q.

The cruise control unit 24 receives a vehicle speed signal VS, an actual gear position signal GP, a speed signal NE, and a gear change signal G/C, and terminals 31 to 33 are used to turn on and off the operation of the cruise control unit 24. Main switch 25 for turning off
, a set switch 26 for setting a target vehicle speed, and a brake switch 27 that closes in response to operation of a brake pedal (not shown) are connected as shown. In response to predetermined operations of these switches, the cruise control unit 24 outputs a fuel supply amount and a signal Q indicating the amount of fuel supply necessary for the vehicle to travel at a required constant speed, and also outputs a signal Q indicating the amount of fuel supply necessary for the vehicle to travel at a constant speed. It is configured to output a signal for changing the target gear position information given to the speed change control device 14 when a situation occurs.

The cruise control section 24 will be explained in detail based on FIG.

The vehicle speed signal VS is input to the target vehicle speed setting section 34, and in response to a level change at the terminal 32 that occurs when the set switch 26 connected to the terminal 32 is closed, the vehicle speed signal VS is adjusted at the time of the level change. Store the contents as the target vehicle speed value. The target vehicle speed data Da set in this manner is input to the travel permission determination section 36 to which the changeover switch 35 and the gear position signal GP are input.

The traveling possibility determining unit 36 determines whether traveling at the set target vehicle speed is possible based on the actual gear position indicated by the actual gear position signal GP and the target vehicle speed indicated by the target vehicle speed data Da. Let's do it. This discrimination can be performed, for example, by map calculation, and the discrimination signal E1 indicating the discrimination result is once latched in the catch section 56,
The output is used as a signal for switching control by the changeover switch 3.
5 is given. Note that this latch portion 56 can be reset,
The output of the match detection section 40, which will be described later, is used to perform the matching. In the illustrated embodiment, when it is determined that it is possible to drive, the level of the determination signal E is "0", and the switch 35 is set to the second
The switching state is shown by the solid line in the figure, and on the other hand, when it is determined that the vehicle cannot be driven, the level of the determination signal E is "1".
", the output level of the latch section 56 becomes "1", and the switch 35 enters the switching state shown by the dotted line in FIG.

Reference numeral 37 designates a provisional target vehicle speed setting unit that responds to the actual gear position signal GP and outputs provisional target vehicle speed data Db indicating a provisional target vehicle speed corresponding to the actual gear position at that time. Db is the switch 38 and the transient target calculation section 3
It is supplied to 9 and 9.

The temporary target vehicle speed data Db is data indicating a vehicle speed value lower than the target vehicle speed indicated by the target vehicle speed data Da,
In response to the temporary target vehicle speed data Db, the transient target calculation unit 39 outputs transient target vehicle speed data Da that changes at a predetermined rate from the value of the temporary target vehicle speed data toward the value of the target vehicle speed data Da over time. do. Transient target vehicle speed data Da
The change may be continuous or stepwise over time. The above-mentioned transient target vehicle speed data DC is applied to the transient target calculation section 59. It is output in response to a predetermined timing of the switching control signal E2.

The transient target vehicle speed data Da is input to the coincidence detection unit 40 to which the target vehicle speed data D& is applied, and here, the value of the transient target vehicle speed data De and the value of the target vehicle speed data D& are compared, and the values of both data are compared. At the timing when the matches match, a match/approach CP is output to the output line 40&. The switching control section 41 to which the gear change signal G/C is applied has a coincidence pulse CP and an allowance torque calculation section 42 to be described later.
The configuration is such that calculation output data TR indicating the calculation results in is input. The switching control section 41 outputs a switching control signal E2 in response to these signals, and this switching control signal E2 is given to the switch 38 and the transient target calculation section 39. In the transient target calculation unit 39, when the calculation output data TH indicates that there is a torque margin, the switching control unit 41 detects that a gear change operation has started based on the gear change signal G/C. In this case, transient target vehicle speed data Dc is output in response to switching control signal E2 indicating this. In addition, the changeover switch 38
also responds to the switching control signal E2 and sets the transient target vehicle speed data Da.
The state shown by the solid line in FIG. 2 is switched to the state shown by the dotted line in response to the output of will be returned to the state of Changeover switch 3
The output from 8 is input to the changeover switch 35, and either the target vehicle speed data Da or the output from the switch 38 is selected depending on the output from the latch section 56.

A speed signal NE, an actual gear position signal GP, and a fuel supply amount signal Q are inputted to the surplus torque calculation section 42, and based on these input signals, the margin state of the output torque of the internal combustion engine 2 is calculated. , the calculation result is output as calculation output data TR.

The data indicating the target vehicle speed taken out from the switch 35 is sent to the cruise Q calculation section 43 to which the vehicle speed signal VB is input.
Here, when comparing the target vehicle speed and the actual vehicle speed, the fuel supply amount required to maintain a given target vehicle speed is K.
The data representing the result of the calculation is outputted as cruise data CQ and input to the changeover switch 44. The changeover switch 44 also includes a data generator 4.
Data FQ indicating that the fuel supply amount is zero is given from 5 and is switched in response to the level of the brake signal BK output from the inverter 46 in response to the operation of the brake switch 27 connected to the terminal 33. Switching control of the switch 44 is performed.

In the illustrated embodiment, the brake is not operated (
When the brake is off (brake OFF), the level of the brake signal BK is "0" and the switch 44 is in the state shown by the solid line in FIG. ), the level of the brake signal BK is rlJ, and the switch 44 is in the state shown by the dotted line in FIG. Therefore, cruise data CQ is taken out as the fuel supply amount signal Q when the brake is not operated, while data FQ is taken out as the fuel supply amount signal Q when the brake is operated.

The engine negative determination section 47 responds to the vehicle speed signal VS, target vehicle speed data Da, actual gear position signal GP, and switching control signal E, and determines whether or not the engine is in a negative state. If it is determined that the engine is in a negative state, the level of the output @47a becomes "1", and if the engine is not in a negative state, the level of the output line 47m becomes "0".

The first instruction unit 48 responds to the calculation output data TRK and outputs first data D indicating the 6th speed position and the target gear position when there is torque margin, and the first data D indicates the actual gear position signal GP. It is input to the changeover switch 49 that is input. Calculation output data TR is applied as a switch changeover control signal to the changeover switch 49, and when the calculation output data TR indicates that there is a torque margin, the changeover switch 49 changes as indicated by the dotted line in FIG. On the other hand, the calculation output data T
If R indicates that there is no torque margin, switching is performed as shown by a solid line there.

The data retrieved by the changeover switch 49 is transferred to the second
The second data D2 output from the instruction section 50 is input to the changeover switch 51. Second instruction part 5
0 responds to the output from the discrimination unit 47 when the engine is negative, and when the level of the output line 47m becomes rlJ, the data indicating the 5th gear position as the target gear position is the second data D2.
The selector switch 51 connects the output line 47m to
Switching is controlled according to the level of That is, the switching state of the changeover switch 51 is such that the level of the output line 47& is "0".
In this case, the state is shown by the solid line in Figure 2;
When the level of the output line 47m is "1", it is in the state shown by the dotted line in FIG. 2.

The signal from the changeover switch 51 is a gear change signal G/
It is taken out via a switch 52 whose opening and closing are controlled by C, and is output as a tentative target gear position signal S indicating a tentative target gear position.

A signal appearing at the terminal 31 in response to the operation of the main switch 25 connected to the terminal 31 is transmitted to the cruise operation control section 5.
The voltage is applied to one input of the dart circuit 55 via a switch 54 whose opening and closing are controlled in response to a control signal E3 from the controller 3. A gear change signal G/C is applied to the other input terminal of the dirt circuit 55, and when the level of the signal from the switch 54 is "1" and the level of the gear change signal G/C is rOJ, the output signal is The switching control signal S
The level of 2 becomes "1".

The cruise operation control unit 53 responds to the vehicle speed signal VS, the input signal from the terminal 32, and the brake signal BK, and determines whether or not to perform constant speed driving control, and determines whether constant speed driving control is to be performed. If the determination is made, the level of the control signal E is set to "1" and the switch 54 is opened. On the other hand, if it is determined that the constant speed driving control should not be performed, the control signal E is set to "1". The level of E3 is set to "0", and the switch 54 is closed. Therefore, the control signal E
When the level of 3 is "0", the gear change signal G/C
is rOJ level, the level of switching control signal S2 is “
When the gear change signal G/C is at the rlJ level, the level of the switching control signal S2 becomes "0".

FIG. 3 shows a detailed block diagram of the engine control unit 23. The first injection amount calculation section 60 uses a speed signal NE
In response to the accelerator signal A, the required fuel supply amount is calculated according to the engine operating conditions at that time according to the predetermined throttle governor characteristics, and a signal indicating the calculation result is outputted as the first supply amount signal QL. On the other hand, the second injection amount calculation section 61
responds to the speed signal NE and the rotation setting signal Nt, calculates the fuel supply amount necessary to maintain the engine speed indicated by the rotation setting signal Nt according to a predetermined isochronous control characteristic, and shows the calculation result. The signal is output as a second supply amount signal QI.

The first and second supply amount signals QL and QI are input to a changeover switch 62 that is controlled in response to the level of the gear change signal G/C. When a gear change is not being performed and the level of the gear change signal G/C is rOJ, the switch 62 is in the state shown by the solid line in FIG. 3, and the first supply amount signal QL is selectively output. . On the other hand, during a gear change, the level of the gear change signal G/C becomes "1", the switch 62 becomes the state shown by the dotted line in FIG. 3, and the second supply amount signal Q! is selected.

The signal selected by the switch 62 is input to the changeover switch 63 to which the fuel supply amount signal Q is input.

The changeover switch 63 is controlled by a changeover signal S2, and the signal selected by the switch 63 is inputted to a circuit 64 for controlling the speed of the internal combustion engine 2 as a signal indicating the amount of fuel supplied. In response to this input signal, the servo circuit 64 outputs a control signal EC for fully controlling the throttle actuator 11, and the throttle actuator 11 controls the opening degree of a throttle valve (not shown) in accordance with this control signal EC. , the speed of the internal control 2 can be controlled according to a signal from the switch 63.

The temporary target gear position signal S output from the cruise control unit 24 is input to the switch 22 to which the target gear position signal GT is input, and the shift control signal E3 is input to the switch 22 to control switching of the switch 22. It is given to 22. The switch 22 is configured such that the level of the switching control signal E is "
0'', the target gear position signal GT is selected, and when the level of the switching control signal E is rlJ, the temporary target gear position signal S is selected.

Next, the operation of the constant speed cruise control system 12 of the internal combustion engine vehicle 1 will be explained based on FIGS. 1 to 3.

When the main switch 25 is open, the cruise control section 24 is not activated and therefore the switching control signals E,
remains at "0", and the target gear position signal GT
is given to the speed change control device 14.

On the other hand, in the engine control unit 23, the switch 63
is maintained in the switched state shown by the solid line.

As a result, the gear of the transmission 5 is changed to the target gear position calculation unit 21.
The clutch actuator 8 and the transmission actuator 9 are controlled by the transmission control device 14 so that the clutch actuator 8 and the transmission actuator 9 are automatically shifted to the target gear position calculated in the step. On the other hand, the speed of the internal combustion engine 2 is controlled according to the first supply amount signal QLK determined by the operation amount of the accelerator pedal 17 and the limit characteristic. During gear change operation, the second supply amount signal QI is input to the servo circuit 64 instead of the first supply amount signal QL by the switch 62, and when the clutch 3 is in the OFF state, the engine speed is set to the isochronous control mode. As a result, the speed is maintained at the speed indicated by the target speed signal (2).

Next, the operation when the switch 25 is closed and the target vehicle speed data Da is set in the target vehicle speed setting section 34 in response to the operation of the switch 26 will be described.

In this case, at the same time as the target vehicle speed data Da is set, the cruise operation control section 53 operates in response to the operation of the switch 26, and sets the vehicle speed to a constant speed, for example, 40 k@/h.

Under the above conditions and the brake is not operated, the level of the switching control signal E is set to "0" and the switch 54 is opened. therefore.

9, unless changing gears? The level of the switching control signal S2 output from the ``-) circuit 55 becomes ``1''.

The switch 63 in the engine control unit 23 is switched as shown by the dotted line. In addition to this, a fuel supply amount signal Q for constant speed driving control outputted from the cruise control section 24 is inputted to the servo circuit 64.

Here, the signal Q is the fuel supply amount signal Q supplied to the circuit 64.
I will explain about it. When setting the target vehicle speed, if the target vehicle speed is appropriate in light of the actual gear position at that time,
It is determined that the vehicle can be driven by the travel permission determining unit 36, the level of the switching control signal E becomes "0", the switch 35 is switched as shown by the solid line, and the target vehicle speed data D is changed.
Cruise Q data CQ is output from cruise Q calculation section 43 based on a. This cruise Qf-ta CQ is output from the cruise control unit 24 as a fuel supply amount signal Q via a switch 44f.

On the other hand, in this case, since the level of the switching control signal E is "1", the temporary target gear position signal S is sent to the speed change control device 14 as the target gear position data via the switch 22. It has been entered. If there is sufficient engine torque and the engine is not losing power, the gear position signal GP is output as the plate target gear position signal S.

That is, the actual gear position at the time when constant speed driving control is entered is given to the speed change control device 14 as a temporary target gear position.

As can be seen from the above explanation, if there is no problem with the set vehicle speed in relation to the actual gear position at that time, and if the engine torque does not have enough margin and the engine is not losing power, the gear when the target vehicle speed is set. At this point, the rotational speed of the internal combustion engine 20 is controlled so that the target vehicle speed is maintained.

In such a state, for example, when the vehicle approaches an uphill slope, the engine load increases, and as a result, the engine loses its spare torque or the engine loses its power, and the drive determination unit 36 issues an error message. Signal E.

As a result of the determination, the content of the plate target gear position signal S is the sixth or fifth gear position, and in response to this, the transmission control device 14 starts a gear shift operation.

At this time, the switch 35 is immediately switched as shown by the dotted line, and the provisional target vehicle speed data Db is provided to the cruise Q calculation section 43. The value of this provisional target vehicle speed data Db is a value determined in advance so that constant speed driving is possible according to the actual gear position at that time.

Thereafter, the switch 49 is switched in response to the calculation output data TH that is output when the margin torque calculation section 42 determines that there is a margin, and the data D indicating the sixth speed is transmitted from the first instruction section 48. A gear shift to 6th gear is performed. At the timing when the gear change signal G/C reaches the rOJ level, the switch 38 is activated by the switching control signal E2.
is switched as shown by the dotted line, and at the same time, the transient target vehicle speed data D is output from the transient target calculation unit 39.
C is input to the cruise Q calculating section 43 via the switch 35.

As a result, as the transient target vehicle speed data De changes from the provisional target vehicle speed data Db toward the target vehicle speed data Da, the vehicle speed gradually increases, and the vehicle is returned to a running state at the vehicle speed indicated by the target vehicle speed data Da.

When the coincidence pulse CP is thereby output, the switching control section 41 responds by returning the switch 38 to the switching state shown by the solid line.At this time, it is determined whether or not the vehicle can travel if the gear shift has enabled the vehicle to travel. When the determination is made in section 36, the switch 35 is returned to the state shown by the solid line, and from this point on, constant speed driving at the desired target vehicle speed continues.

(Effects of the Invention) According to the present invention, as described above, when constant speed driving at the set target vehicle speed becomes impossible, the content of the target gear position is changed to a lower gear position, and The content of the target vehicle speed is also set to a vehicle speed value lower than the above-mentioned target vehicle speed, and in this state, it is determined whether or not it is possible to shift up the transmission, and the upshift is executed based on the result of that determination. Therefore, when the IC gear is shifted up after a gear shift down, it is possible to effectively prevent the gear shift down operation from being performed again. Therefore, when it is necessary to operate the gearbox 7 on an uphill slope, etc., it is possible to effectively prevent the problem of frequently repeating the gearshift up and gearshift down/down operations. It has an excellent effect that rarely occurs.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of a vehicle control device which performs constant speed running control of a vehicle according to the method of the present invention, and FIG. 2 shows a cruise control unit shown in FIG. 1. Detailed Block Diagram, FIG. 3 is a detailed block diagram of the engine control unit 23 shown in FIG. DESCRIPTION OF SYMBOLS 1... Internal combustion engine vehicle, 2... Internal combustion engine, 5... Transmission, lO... Automatic transmission control system, 12... Constant speed running control system, 24... Cruise control section, 34 ...Target vehicle speed setting unit, 36...Drivability determination unit, 37...
Temporary target vehicle speed setting section, 42... margin torque calculation section, 47
. . . engine negative is a discrimination section, 48 . . . first instruction section, 5
o...Second instruction section, Da...Target vehicle speed data, Db
...Temporary target vehicle speed data, GT...Target gear position signal, Dl...First data, D2-. Second data, TR...calculated output data, S,...plate target gear position signal, S2-...switching control signal, Nt...
・Target speed signal, Q...Fuel supply amount signal.

Claims (1)

[Claims] 1. In a constant speed driving control method for a vehicle for controlling the vehicle speed of an internal combustion engine vehicle equipped with an automatic transmission to maintain it at a predetermined set vehicle speed, when the predetermined set vehicle speed cannot be maintained, the automatic The contents of the target gear position given to the transmission device are changed to contents indicating a lower gear position, and the contents of the set vehicle speed are changed to contents indicating a lower vehicle speed, and in the control state obtained as a result, the shift is performed. Determining whether or not the device is capable of upshifting, and when it is determined that upshifting of the transmission device is possible, causing the transmission to perform an upshifting operation and changing the contents of the set vehicle speed before changing. A constant speed running control method for a vehicle, characterized in that the original content is restored.