JPH09240313A - Constant speed running device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a failure of brake switches in two systems to be detected. SOLUTION: Brake switches BRK1 and BRK2 in two systems are mechanically cooperated with a striding action of a brake pedal to change over their ON/OFF states. A first brake switch BRK1 is a normal-opened switch and its ON/OFF signal is inputted to an input port PORT 1 of a CPU 50. A second brake switch BRK2 is a normal-closed switch in a surplus system and its ON/ OFF signal is inputted to an input port P0RT2 of the CPU 50. The second brake switch BRK2 and a transistor TrR are arranged in series in an electrical energization path for a release solenoid valve (VR) 35 of a negative pressure diaphragm actuator. The CPU 50 monitors ON/OFF state of each of the two brake switches BRK1 and BRK2, combines their ON/OFF states to detect a failure of each of the brake switches BRK1 and BRK2, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle constant speed traveling device having a function of releasing cruise control when a brake pedal is depressed during constant speed traveling control (hereinafter referred to as "cruise control"). Is.

[0002]

2. Description of the Related Art Conventionally, during cruise control,
As one means for switching to the normal control by the driver's accelerator operation, for example, as shown in JP-B-2-2739, the cruise control is released when the brake pedal is depressed. There is. Further, a redundant design as shown in FIG. 16 is known so that the cruise control can be surely canceled even if some abnormality occurs in the cruise control system. In this redundant design, two systems of brake switches SW1 and SW2 are provided that can be switched on / off in conjunction with the depression operation of the brake pedal.

Here, the first brake switch SW1
Is an ON signal (high level signal) when the brake pedal is depressed
The second brake switch SW2 is a normally closed switch that is provided as a redundant system in the energization path to the actuator 4 for cruise control as a redundant system. Further, the control circuit 3 has a built-in switching element (not shown) for turning on / off the energization path to the actuator 4, and when the driver depresses the brake pedal, an on signal from the first brake switch SW1. By turning off the switching element in the control circuit 3 by means of, the power supply to the actuator 4 is cut off. At this time, at the same time, the second brake switch SW2 is turned off in conjunction with the operation of depressing the brake pedal, so that the energization path to the actuator 4 is cut off and the control circuit 3
Even if something goes wrong with the cruise control, the cruise control can be reliably released.

[0004]

SUMMARY OF THE INVENTION In the above configuration, tentatively,
Even if an abnormality occurs in the first brake switch SW1 or the control circuit 3, if the second brake switch SW2 functions normally, the power supply path to the actuator 4 can be cut off and the cruise control can be reliably released. Since the first brake switch SW1 is also a switch for turning on / off the stop lamp, the first brake switch SW1
The failure can be easily detected by the abnormality of the stop lamp.

On the other hand, the second brake switch SW
Since 2 is originally provided as a redundant system, the cruise control can be canceled by the first brake switch SW1 even if a failure occurs in which the second brake switch SW2 is constantly turned on due to contact fusion or the like. Therefore, there is no problem with the cruise control function. Therefore, even if the failure occurs at some point during use of the vehicle, the driver cannot notice the failure at all.

The present invention has been made in view of the above circumstances, and therefore an object thereof is to provide a vehicle constant speed traveling device capable of detecting a failure of two brake switches. .

[0007]

In order to achieve the above object, the vehicle constant speed traveling apparatus according to claim 1 of the present invention interlocks with the depressing operation of the brake pedal to operate the first and second brake switches. When the first brake switch is turned on / off and the first speed brake control is activated during the constant speed traveling control, the switch means provided in the energization path to the actuator is turned off to cut off the energization to the actuator. Release the high speed travel control (cruise control). Further, during the constant speed traveling control, the failure diagnosis means monitors the on / off state of the first and second brake switches, and the combination of the on / off states diagnoses whether or not each brake switch has a failure.

For convenience of explanation, if the first brake switch is a normally open switch, the first brake switch is off and the second brake switch is on when the brake pedal is not depressed. When the brake pedal is depressed, the first brake switch is on and the second brake switch is off. Therefore, 2
When the brake switch of the system operates normally, the relationship that one of them is on and the other is off is maintained. Therefore, when both of the two systems of brake switches are on or off, it means that one of the brake switches is out of order. When the first brake switch is a normally closed switch, a failure occurs when one of the two systems of brake switches is on and the other is off. Utilizing this relationship, the failure of each brake switch is detected by the combination of the ON / OFF states of the first and second brake switches.

By the way, the first and second brake switches are mechanically interlocked with the depression operation of the brake pedal to turn them on / off. Therefore, when the brake pedal is depressed slowly, both brake switches are turned on. The ON / OFF switching timing may be slightly deviated, and during this period of deviation, the combination of the ON / OFF states of both brake switches is the same as that at the time of failure, which causes a decrease in failure diagnosis accuracy. The deviation of the on / off switching timing of both brake switches also occurs due to an assembly error of parts.

Therefore, in the second aspect, it is diagnosed that there is a failure when the combination of the ON / OFF states of the first and second brake switches is in the failure mode for a predetermined time or more. As a result, it is possible to prevent erroneous diagnosis of a failure due to a shift in the on / off switching timing of both brake switches, and improve the reliability of failure diagnosis.

Further, in claim 3, the failure diagnosis is repeatedly performed, and finally the failure is diagnosed when the diagnosis result of the failure is repeated a predetermined number of times. By repeating the failure diagnosis in this way, it is possible to eliminate erroneous diagnosis and improve the reliability of failure diagnosis.

Further, in claim 4, when the failure diagnosis is repeated after the failure is diagnosed, and the combination of the ON / OFF states of the first and second brake switches continues for a predetermined time or more. Then, cancel the previous diagnosis result of failure. As a result, even if a failure is erroneously diagnosed for some reason, the erroneous diagnosis can be canceled later, and the reliability of the failure diagnosis can be improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIGS. First, the overall configuration of the vehicle constant speed traveling device will be described with reference to FIG. A throttle valve 12 is provided in the throttle body 11 via a shaft 13 so as to be openable and closable. Throttle actuator 14 for driving this throttle valve 12
Is constituted by using, for example, a DC motor or a step motor, and the throttle valve 12 is biased to the open side by the spring 10.

Further, the throttle body 11 is provided with a throttle opening sensor 15 for detecting a throttle opening (opening of the throttle valve 12), and a throttle opening signal from the throttle opening sensor 15 is sent to an electronic control unit ( (Hereinafter abbreviated as "ECU") 16 is input. In addition to the throttle opening signal, the ECU 16 sends the vehicle speed signal output from the vehicle speed sensor 17 to the accelerator pedal 1.
8 is an accelerator opening signal output from an accelerator opening sensor 19 for converting the depression amount into an electric signal, a mechanical guard opening signal output from a mechanical guard opening sensor 38 for converting a mechanical guard opening into an electric signal, and a cruise control switch. C / C signal output from 20 is input, and E
The CU 16 controls the throttle actuator 14 based on these signals. The accelerator pedal 18 is connected to an accelerator lever 23 via a wire 22 wound around a roller 21.

On the other hand, the mechanical guard mechanism 24 that mechanically limits the maximum opening of the throttle valve 12 includes a mechanical guard 25 that moves in parallel in the vertical direction in FIG. 1, and a spring that biases the mechanical guard 25 toward the closing side (downward). And 26. The left end of the mechanical guard 25 is located right above a lever 27 that rotates integrally with the throttle valve 12, and the lever 27 is biased toward the open side (upward) by a spring 28. The magnitude relationship between the biasing force of the spring 28 of the lever 27 and the biasing force of the spring 26 of the mechanical guard mechanism 24 is set so that the latter is larger than the former.

Normally, the throttle valve 12 is biased to the open side by a spring 28, but the throttle valve 1
2 opening is allowed because lever 27 is mechanical guard 2
When the lever 27 comes into contact with the mechanical guard 25, the opening of the throttle valve 12 is prevented by the urging force of the spring 26 of the mechanical guard mechanism 24 thereafter. As a result, the throttle opening does not exceed the mechanical guard opening determined by the position of the mechanical guard 25.

Further, the lower limit opening of the mechanical guard 25 is limited by the accelerator lever 23 which is interlocked with the depression operation of the accelerator pedal 18. Further, the accelerator lever 23 is biased toward the closing side by a spring 40, and a fully closed stopper 41 is provided below the accelerator lever 23 (close side). In addition, this accelerator lever 2
3, a through hole 29 is formed, and the wire 22 of the accelerator pedal 18 is inserted through the through hole 29. A stopper 30 is fixed to the wire 22 below the mechanical guard 25.

When the driver depresses the accelerator pedal 18 during normal control (except during cruise control), the accelerator lever 23 is moved upward (open side) in synchronization with the depression of the accelerator pedal 18.
The mechanical guard 25 whose lower limit opening is limited by the accelerator lever 23 also moves upward (open side). Therefore, the throttle valve 12 (lever 27) can freely move below the mechanical guard 25 (close side).

On the other hand, the mechanical guard opening (position of the mechanical guard 25) can be changed by the mechanical guard actuator 31. The mechanical guard actuator 31 is composed of, for example, a negative pressure diaphragm type actuator having a diaphragm (not shown) built therein, and is provided with a movable rod 32 which moves up and down by the displacement of the diaphragm. The lower end of the movable rod 32 is connected to the left side of the mechanical guard 25 via a stopper 32a, and the mechanical guard 25 moves up and down in conjunction with the vertical movement of the movable rod 32.

The mechanical guard actuator 31 is provided with a negative pressure side electromagnetic valve (VV) 33, an atmosphere side electromagnetic valve (VA) 34, and a release electromagnetic valve (VR) 35 for controlling the negative pressure acting on the inside. Are controlled by the ECU 16. Here, the energization of the release electromagnetic valve (VR) 35 is also cut off by the output signal of the first brake switch BRK1 described later. As a result, even if the ECU 16
Due to some failure, negative pressure side solenoid valve (VV) 33
Even if the power continues to be energized, by depressing the brake pedal (not shown), the power to the negative pressure side electromagnetic valve (VV) 33 can be surely cut off, thereby preventing the movable rod 32 from rising continuously. can do.

The ECU 16 stores a control routine for the number of duplicates in a ROM 54, which will be described later, and executes these control routines to control a throttle opening degree according to a normal accelerator operation amount and a cruise control. The throttle opening control according to the vehicle speed and the mechanical guard opening control according to the throttle opening during cruise control are performed to function as the control means in the claims.
In particular, during cruise control, the negative pressure side electromagnetic valve (VV) 33 and the atmosphere side electromagnetic valve (VA) 34 are turned on / off to make the mechanical guard opening slightly larger than the throttle opening. For controlling the actuator 31.

Next, the hardware configuration of the ECU 16 will be described with reference to FIG. The ECU 16 mainly includes the CPU 5
0, analog buffer (A / D converter) 51, digital buffer 52, rectangular wave processing circuit 53, ROM 54 storing control programs and control data tables, RAM 55 temporarily storing various data, drive circuit 56, D /
An A converter 57, a comparison circuit 58, a drive circuit 59 and the like are provided.

Output signals from the throttle opening sensor 15, the accelerator opening sensor 19, the mechanical guard opening sensor 38, and the cruise control switch 20 are input to an analog buffer (A / D converter) 51 of the ECU 16. The digital buffer 52 of the ECU 16 includes:
Output signals from the cruise main switch 60 and the first and second brake switches 61 and 62 are input. The output signal from the vehicle speed sensor 17 is input to the rectangular wave processing circuit 53 of the ECU 16. These signals are CP
Input to U50.

The CPU 50 processes the various signals described above according to a control program stored in the ROM 54 in advance, and calculates a target opening of the throttle valve 12 (a target voltage of the throttle opening sensor 15) described later. The calculated value of the target voltage of the throttle opening sensor 15 is converted into an analog voltage via the D / A converter 57 and input to the drive circuit 59 of the throttle actuator 14 having an analog feedback function. The comparison circuit 58 of the drive circuit 59 controls the throttle actuator 14 so that the target voltage is equal to the actual voltage (the output of the throttle opening sensor 15). Further, during cruise control, as described above, the negative pressure side electromagnetic valve (VV) 3 of the mechanical guard actuator 31 is set so that the mechanical guard opening is slightly larger than the throttle opening.
3, the atmosphere side electromagnetic valve (VA) 34 and the release electromagnetic valve (VR) 35 are driven by the drive circuit 56.

Next, based on FIG. 3, a negative pressure side electromagnetic valve (V) for controlling the negative pressure in the mechanical guard actuator 31.
V) 33, atmosphere side electromagnetic valve (VA) 34 and release electromagnetic valve (VR) 35 will be described. A negative pressure side electromagnetic valve (VV) 33 and a release electromagnetic valve (VR) 35 are provided in the negative pressure introduction path 71 for introducing the negative pressure of the negative pressure source into the negative pressure chamber of the actuator 31. The negative pressure side electromagnetic valve (VV) 33 is a normally closed two-way valve, and is opened when it is turned on. Release solenoid valve (VR) 35
Is a three-way valve, and when it is on the negative pressure side electromagnetic valve (VV)
33 and the negative pressure chamber of the actuator 31 are communicated with each other,
Negative pressure can be introduced into the negative pressure chamber of the actuator 31, and the downstream side of the negative pressure side electromagnetic valve (VV) 33 is shut off at the time of OFF to communicate the negative pressure chamber of the actuator 31 with the atmosphere.

Further, in the negative pressure chamber of the actuator 31,
Atmosphere communication passage 72 having atmosphere-side electromagnetic valve (VA) 34
Are connected. This atmosphere side electromagnetic valve (VA) 34
Is a three-way valve, but has a blind plug in the on direction, and shuts off the air communication passage 72 when it is on, and opens the air communication passage 72 when it is off to connect the negative pressure chamber of the actuator 31 to the atmosphere. .

These electromagnetic valves 33, 34, 35 are connected to a drive circuit 56, and ON / OFF is controlled by an output signal of the CPU 50. For example, in order to pull up the mechanical guard 25 (introduce a negative pressure into the negative pressure chamber of the actuator 31), all the electromagnetic valves 33, 34, 35 may be turned on. On the contrary, in order to lower the mechanical guard 25 (release the negative pressure in the negative pressure chamber of the actuator 31), one of the atmosphere side electromagnetic valve (VA) 34 and the release electromagnetic valve (VR) 35 should be turned off. Of course, it goes without saying that both can be turned off.

Next, the electric circuit configuration of the control system of the cruise control system will be described with reference to FIG. VV,
The drive circuit 56 for driving the electromagnetic valves 33, 34, 35 of VA, VR has three transistors TrV, TrA,
Each transistor TrV, Tr is composed of TrR.
Base of A and TrR is output port XRV of CPU50
It is connected to V, XRVA, and XRVR. Negative pressure side electromagnetic valve (VV) 33 and atmosphere side electromagnetic valve (VA) 34
Are connected between the collectors of the NPN type transistors TrV and TrA and the battery (+ B), respectively.
When the output level of the 50 output ports XRVV, XRVA is high level (Hi), the transistors TrV, TrA
Is turned on, and the negative pressure side electromagnetic valve (VV) 33 and the atmosphere side electromagnetic valve (VA) 34 are turned on.

On the other hand, the release solenoid valve (VR) 35
Is connected between the collector of the PNP transistor TrR and the ground terminal, and the emitter of the transistor TrR is connected to the battery (+ B) via the second brake switch BRK2 and the cruise main switch 60. In this case, the release solenoid valve (VR) 35 is
The second brake switch BRK2 and the transistor TrR (corresponding to the switch means in the claims) are provided in series in the energizing path to the release electromagnetic valve (VR) 35, which corresponds to the actuator in the claims. It is composed. This second brake switch BRK2
ON / OFF signal is input port PORT2 of CPU50
The ON / OFF signal of the cruise main switch 60 is input to the input port PORTC of the CPU 50.

The cruise main switch 60 and the second
If both brake switches BRK2 are turned on, the input level of the input port PORT2 is high level (Hi).
Becomes After that, when the second brake switch BRK2 is turned off, the input level of the input port PORT2 is inverted to the low level (Lo).

The second brake switch BRK2 has a first
Like the brake switch BRK1 of No. 3, it is installed so that it can be switched on / off mechanically in conjunction with the depression operation of a brake pedal (not shown). The first brake switch BRK1 is a normally-open type switch, and the second
The brake switch BRK2 is a normally closed switch provided as a redundant system.

ON / OFF of the first brake switch BRK1
The off signal is input to the input port PORT1 of the CPU 50. When the first brake switch BRK1 is off, the input level of the input port PORT1 of the CPU 50 becomes Hi due to the pull-up resistor 63. Then, by pressing the brake pedal, the first brake switch B
When RK1 is turned on, the input level of the input port PORT1 is inverted to Lo. Along with this, the output levels of the output ports XRVV, XRVA, XRVR of the CPU 50 are all inverted to Lo, and all the transistors TrV, TrA,
TrR is turned off, all the electromagnetic valves 33, 34, 35 are turned off, the negative pressure chamber of the actuator 31 is communicated with the atmosphere, and the cruise control is released.

Next, the processing procedure for setting the cruise control (hereinafter referred to as "C / C") mode CRMOD executed by the CPU 50 in the ECU 16 will be described with reference to the flowchart shown in FIG. The C / C mode setting routine shown in FIG. 5 is executed, for example, every 8 ms. In the following description of the specification, the data enclosed by "" represents a hexadecimal number.

In this routine, first in step 101,
Whether or not a basic condition for executing C / C is satisfied is determined by whether or not the C / C condition flag XRENAB is "1". Here, the basic conditions for executing the C / C include, for example, that the parking brake is not applied, the vehicle speed is not excessive (for example, 200 km / h or more), and the gear is not in neutral. If this condition is not satisfied (XRENAB ≠ 1), the process proceeds to step 102, CRMOD = "00" is set, and no command is accepted even if the cruise control switch 20 is pressed.

On the other hand, if the condition is satisfied (XRENAB = 1), the routine proceeds to step 103, where the vehicle speed is set S
Whether or not the ET command has already been accepted is determined by whether or not the cruise active flag XRACT is "1". If the SET command is not accepted (XRACT ≠ 1), the process proceeds to step 104,
Set vehicle speed SRSETM stored in RAM 55
Determines whether 0 <SRSETM ≦ KRSETMX is satisfied. Here, KRSETMX is the upper limit vehicle speed (200 km / h) at which C / C can run at a constant speed. if,
If SRSETM = 0 or SRSETM> KRSETMX, the routine proceeds to step 105, where C / C mode CRMO
When D = “01”, acceptance of the SET command is permitted, and this routine is ended.

In step 104, 0 <SRS
If the condition of ETM ≦ KRSETMX is satisfied, the routine proceeds to step 106, where C / C mode CRMOD = “0”.
2 ", the acceptance of the SET command and the RESUME command is permitted, and this routine is ended.

On the other hand, in step 103, XRACT
When = 1 (when the SET command has already been accepted), the routine proceeds to step 107, where it is determined whether or not XWCC = 1, that is, the target throttle opening is larger than the target throttle opening determined by the accelerator opening. Or not.
When XWCC = 1, the process proceeds to step 108 and C /
C mode CRMOD = “03”, CANCEL command, ACCEL command, DECEL command, I
The acceptance of the NCH-UP command and the INCH-D0WN command is permitted, and this routine ends. The driving state at this time corresponds to a situation in which the driver is not physically depressing the accelerator pedal 18 while the vehicle is physically traveling in C / C or a state in which the depression angle is small even when depressing the accelerator pedal 18.

On the other hand, in step 107, XWCC
If ≠ 1, the process proceeds to step 109, the C / C mode CRMOD = "04" is set, the acceptance of the CANCEL command and the SET command is permitted, and this routine is ended. The driving state at this time is physically equivalent to a situation in which the driver is depressing the accelerator pedal 18 during C / C traveling (when the driver operates the accelerator to increase the additional speed during C / C traveling). To do.

Next, the processing contents of the C / C release routine shown in FIG. 6 will be described. This routine is executed, for example, every 8 ms, and when the brake pedal is depressed, C / C is released as follows. First, in step 111, C / C
It is determined whether or not the mode CRMOD is “01” or “02”, and if the CRMOD = “01” or “02”, it means that the C / C traveling is not currently in progress, so the following processing is not performed and the operation is directly performed. Exit the routine.

On the other hand, CRMOD ≠ “01” or “02”
If it is, proceed to step 112 and enter C / C mode CR
It is determined whether MOD is "00", and CRMOD = "0".
In the case of 0 ", the routine proceeds to step 114, where the operation for canceling C / C, that is, the cruise active flag XRACT and the memory set vehicle speed SRSET are both cleared, and C / C is cancelled.

On the other hand, in step 112, CRMO
If D ≠ “00”, the process proceeds to step 113, and CP
Whether or not the input level of the input port PORT1 of U50 is Lo, that is, when the brake pedal is depressed
It is determined whether or not the brake switch BRK1 is turned on. When the input level of PORT1 is Lo, that is, when the brake pedal is depressed, the routine proceeds to step 114, where XRACT = 0 and SRSET = 0 are set, and C / C is set.
Cancel. When the input level of PORT1 is Hi, the brake pedal is not depressed, so C / C
This routine ends without canceling.

Next, the processing contents of the mechanical guard drive routine shown in FIG. 7 will be described. This routine is executed, for example, every 8 ms, and the mechanical guard 25 is controlled near the target mechanical guard opening PRMGT as shown in FIG. First, at step 121, it is determined whether the C / C mode CRMOD is "03", that is, whether the driver is traveling at a constant speed at C / C without stepping on the accelerator pedal. CRMO
When D ≠ “03” (when not C / C traveling), it is not necessary to drive the mechanical guard 25, so step 12
Go to 2 and output ports XRVV, XRV of CPU 50
The output levels of A and XRVR are set to 0 (Lo), all the electromagnetic valves 33, 34 and 35 are turned off, the negative pressure chamber of the actuator 31 is communicated with the atmosphere, and this routine ends.

On the other hand, if CRMOD = "03" (C / C running), the routine proceeds to step 123, where the target mechanical guard opening PRMGT is calculated by the following equation. PRMGT = PWCC + KRCC where PWCC is the target throttle opening and KRC
C is a constant term.

In the next step 124, the deviation DRPMG between the target mechanical guard opening PRMGT and the actual mechanical guard opening PWMG is calculated, and in the following step 125, the deviation DRPMG is DRPMC> KRPMGB, 0 ≦ D.
RPMG ≤ KRPMBGB, one KRPMBGB ≤ DRPM
It is determined which of G <0, -KRPMGB> DRPMG it corresponds to, and the next step is determined. Here, KRPMB is an allowable deviation.

If DRPMG> KRPMGB,
The actual mechanical guard opening PWMG is the target mechanical guard opening P
It is far below RMGT. In this case, the processing of steps 126 and 136 is executed, and C
The output levels of the output ports XRVV, XRVA, XRVR of the PU 50 are all set to 1 (Hi), and all the electromagnetic valves (VV) 33, 34, 35 are turned on. As a result, a negative pressure is introduced into the negative pressure chamber of the actuator 31 from the negative pressure source, and the mechanical guard opening PWMG is rapidly increased.

When 0 ≦ DRPMG ≦ KRPMBGB, the actual mechanical guard opening PWMG is slightly below the target mechanical guard opening PRMGT within the allowable range. In this case, in steps 127 to 129,
The output level of the output port XRVV was previously processed (8ms
The same as the previous), the ON / OFF of the negative pressure side electromagnetic valve (VV) 33 is maintained in the same state as the previous processing (8 ms before), and the output port X is set in Steps 135 and 136.
The output levels of RVA and XRVR are set to 1 (Hi), and the atmosphere side electromagnetic valve (VA) 34 and the release electromagnetic valve (VR) 35 are turned on. As a result, the negative pressure in the negative pressure chamber of the actuator 31 is maintained or increased, and the mechanical guard opening PWMG is maintained or increased.

When -KRPMGB≤DRPMG <0, the actual mechanical guard opening PWMG is slightly above the target mechanical guard opening PRMGT within the allowable range. In this case, the process proceeds to step 130, the output level of the output port XRVV is set to 0 (Lo), the negative pressure side electromagnetic valve (VV) 33 is turned off, and the negative pressure source is shut off. Then, in steps 131 to 133, the output level of the output port XRVA was previously processed (8 ms).
The previous state is maintained the same as before, and the on / off state of the atmosphere side electromagnetic valve (VA) 34 is maintained in the same state as the previous processing (8 ms before). After this, in step 136, output port XRVR
Output level is maintained at 1 (Hi) and the release electromagnetic valve (VR) 35 is maintained in the ON state. As a result, the negative pressure in the negative pressure chamber of the actuator 31 is maintained or reduced, and the mechanical guard opening PWMG is maintained or reduced.

In the case of -KRPMB> DRPMG, the actual mechanical guard opening PWMG greatly exceeds the target mechanical guard opening PRMGT.
In this case, the process proceeds to step 134 and the output port XR
Set the output level of VV and XRVA to 0 (Lo),
Negative pressure side solenoid valve (VV) 33 and atmosphere side solenoid valve (V
A) Turn off 34. As a result, the actuator 31
The negative pressure chamber of is communicated with the atmosphere, and the mechanical guard opening PWMG
To decrease rapidly. Even in this case, step 13
6 and set the output level of the output port XRVR to 1 (H
i), and the release solenoid valve (VR) 35 is maintained in the ON state.

Next, the failure mode and failure determination method of the first brake switch BRK1 and the second brake switch BRK2 will be described with reference to FIG. The cruise main switch 60 is on and the two-system brake switch BRK
When 1 and BRK2 are normal, the input levels of the input ports PORT1 and PORT2 of the CPU 50 always move the same. In other words, when you do not press the brake pedal,
Both the input ports PORT1 and PORT2 become Hi,
When you press the brake pedal, input ports PORT1 and PO
Both RT2 are inverted to Lo.

Failures of the brake switches BRK1 and BRK2 include a short-circuit failure in which the first brake switch BRK1 is constantly turned on due to contact fusion or the like, an open failure in which the first brake switch BRK1 is always turned off, and a second brake switch. BRK2 short circuit failure, second
There are four types of failure modes: open failure of the brake switch BRK2. In any failure mode, the combination of the input levels of the input ports PORT1 and PORT2 is different from that in the normal state.

Utilizing this relationship, when the brake pedal is not depressed, the input ports PORT1 and PORT2 are
When both are Hi, it is determined to be normal, and one of them is Lo.
When it is determined to be a failure. At this time, input port POR
If T1 is Lo, the first brake switch BRK
If the input port PORT2 is Lo, it is determined that the second brake switch BRK2 is open.

Further, when the brake pedal is depressed, it is determined that both input ports PORT1 and PORT2 are normal, and if either one is Hi, it is determined to be faulty. At this time, if the input port PORT1 is Hi, it is determined that the first brake switch BRK1 is open, and if the input port PORT2 is Hi,
It is determined that the second brake switch BRK2 has a short circuit failure.

Next, the processing contents of the brake switch failure diagnosis routine shown in FIGS. 10 and 11 will be described. This routine is executed every predetermined time (for example, every 262 ms) and functions as a failure diagnosis means for diagnosing whether or not there is a failure in the brake switches BRK1 and BRK2. In this routine, first, at step 141, it is judged if the input port PORTC is Hi, that is, if the cruise main switch 60 is on, and if PORTC = Lo (cruise main switch 60 is off). Since the failure diagnosis cannot be performed for this, this routine is ended as it is.

When PORTC = Hi (cruise main switch 60 is on), the routine proceeds to step 142 in order to carry out a failure diagnosis, and each brake switch BRK1, BRK1.
Input port PORT to read the on / off status of RK2
1, PORT2 Hi / Lo combination (PORT
1, PORT 2) determines the next step.

That is, if it is (Hi, Hi), it is in a normal state, and the routine proceeds to step 143, where a normal state duration time counter CBKN1 for counting the duration of (Hi, Hi).
Is incremented and the process proceeds to step 147.

If (Lo, Lo), it means a normal state,
Proceeding to step 144, the second normal state duration counter CBKN2 for counting the duration of (Lo, Lo)
Is incremented and the process proceeds to step 147.

If (Lo, Hi), there is a failure condition,
Proceeding to step 145, the first failure state duration counter CBKF1 for counting the duration of (Lo, Hi)
Is incremented and the process proceeds to step 147.

If (Hi, Lo), then there is a fault condition,
Proceeding to step 146, the second failure state duration time counter CBKF2 for counting the duration time of (Hi, Lo)
Is incremented and the process proceeds to step 147. These counters CBKN1, CBKN2, CBKF1, CB
The maximum value of each KF2 is "FF".

In the processing after step 147, when the count values of the normal state duration and the fault state duration counted by these counters reach the predetermined values, the normal state integration counter and the abnormal state integration counter are incremented, and the Normal when the count value reaches the specified value,
Determine the abnormality. As a result, normality / abnormality is accurately determined.

That is, in step 147, (Hi, H
i) the normal state duration CBKN1 is the predetermined time KBKN
It is determined whether T has been reached, and if it has, step 1
Proceed to step 48, and normal state integrating counter C of (Hi, Hi)
BKNN1 is incremented and the process proceeds to the next step 149. On the other hand, the normal state duration CBK of (Hi, Hi)
If N1 has not reached KBKNT for the predetermined time, step 148 is skipped and step 149 is proceeded to.

In this step 149, (Lo, Lo)
It is determined whether or not the normal state duration time CBKN2 has reached the predetermined time KBKNT.
To the normal state integration counter CBK of (Lo, Lo)
NN2 is incremented and the process proceeds to the next step 151. On the other hand, the normal state duration CBKN of (Lo, Lo)
If 2 has not reached KBKNT for the predetermined time, step 150 is skipped and step 151 is proceeded to.

In this step 151, (Lo, Hi)
It is determined whether the failure state duration time CBKF1 of has reached the predetermined time KBKFT, and if it has reached, the step 152
To the failure status integration counter CBK of (Lo, Hi)
FF1 is incremented and the process proceeds to the next step 153. On the other hand, the failure state duration CBKF of (Lo, Hi)
If 1 has not reached KBKFT for the predetermined time, step 152 is skipped and step 153 is proceeded to.

At this step 153, (Hi, Lo)
It is determined whether the failure state duration time CBFK2 of has reached the predetermined time KBKFT, and if it has reached, step 154
To the (Hi, Lo) failure state integration counter CBK
The FF2 is incremented and the process proceeds to the next step 155. On the other hand, the failure state duration CBFK of (Hi, Lo)
If 2 has not reached KBKFT for the predetermined time, step 154 is skipped and step 155 is proceeded to. In addition, CBK
The maximum count value of each of the NN1, CBKNN2, CBKFF1, and CBKFF2 is "FF".

At step 155, the input port PO
It is determined whether the states of RT1 and PORT2 have changed from the previous state, that is, whether the brake pedal has been depressed from the undepressed state, or whether the depression has been released from the depressed state. In this step 155, "Yes"
If it is determined that all the normal / fault state duration time counters are cleared, the process proceeds to step 157. On the other hand, if it is determined as “No” in step 155, the process skips step 156 and proceeds to step 157.

In this step 157, (Hi, H
i), (Lo, Lo) normal state integration counter C
It is determined whether BKNN1 and CBKNN2 are both larger than a predetermined value KBKNN, and if "Yes", step 1
Proceed to step 58 to clear the fail flag XFAIL,
If “No”, the process directly proceeds to the next step 159. By thus providing the means for clearing the fail flag XFAIL, even if the failure is erroneously detected due to some cause, the erroneous detection is canceled if the normal state continues.

At step 159, (Lo, Hi),
(Hi, Lo) failure status integration counter CBKFF1,
It is determined whether or not any one of CBKFF2 is larger than a predetermined value KBKFF, and if “Yes”, step 16
In step 0, the fail flag XFAIL is set to "1" indicating a failure, and if "No", this routine is finished. The information of the fail flag XFAIL may be used to notify the driver of a failure by turning on a warning lamp (not shown) or the ECU 1
It may be stored in a backup memory (not shown) in 6 as diagnosis data so that a service person can know the failure at the time of inspection at a service factory.

By the way, since the first and second brake switches BRK1 and BRK2 are mechanically interlocked with the operation of depressing the brake pedal to turn them on / off, both brake switches are operated when the brake pedal is depressed slowly. The on / off switching timing of the switches BRK1 and BRK2 may be slightly deviated, and the combination of the on / off states of both the brake switches BRK1 and BRK2 becomes the same as that at the time of the failure during the period of this deviation. The deviation of the on / off switching timing of the brake switches BRK1 and BRK2 also occurs due to an assembly error of parts.

In this respect, in the above embodiment, the first and second
When the combination of the on / off states (Hi / Lo) of the brake switches BRK1 and BRK2 of No. 2 is in the failure mode for a predetermined time or more, the failure state integration counter is incremented. If the state is below the predetermined time, it is not judged as a failure, and the brake switches BRK1, BRK2
It is possible to prevent an erroneous diagnosis of a failure due to a shift in the on / off switching timing of, and improve the reliability of the failure diagnosis.

Further, in the above-described embodiment, when the failure diagnosis is repeatedly performed and the count value of the failure state integration counter for integrating the number of times of diagnosis of failure has reached a predetermined value,
Since it is finally diagnosed that there is a failure, in combination with the operation of counting the failure state duration time described above, it is possible to more reliably eliminate erroneous diagnosis and further improve the reliability of failure diagnosis.

Moreover, in the above embodiment, the failure diagnosis is repeated after the failure is diagnosed, and the combination of the ON / OFF states of the first and second brake switches BRK1 and BRK2 is normal for a predetermined time or more. When it continues, the previous diagnosis result of failure is canceled (that is, the fail flag XFAIL is cleared).
Even if a failure is erroneously diagnosed for some reason, the erroneous diagnosis can be canceled later, and the reliability of the failure diagnosis can be improved in this respect as well.

In the embodiment described above, the throttle valve 12 is driven by the actuator 14 (motor) to adjust the throttle opening even during normal control (other than C / C). In another embodiment of the present invention shown in FIG. 15, the accelerator pedal 18 and the throttle valve 12 are mechanically connected by a throttle cable 65, and the accelerator pedal 1 is normally operated during normal control.
The throttle lever 27 is rotated in accordance with the movement of 8, and the throttle valve 12 is opened and closed.

On the other hand, at the time of C / C, the opening of the throttle valve 12 is adjusted by rotating the throttle shaft 74 by the C / C actuator 66, and the vehicle speed is controlled to the set vehicle speed. In this case, the C / C actuator 66 has a structure in which an electromagnetic clutch 69 is interposed between the motor 67 and the control arm 68.
At the time of C / C, the electromagnetic clutch 69 is energized to transmit the rotation of the motor 67 to the control arm 68, and the rotation of the control arm 68 is transmitted to the throttle shaft 74 via the cable 70.
Adjust the opening of 2.

Next, the electric circuit configuration of the control system of the cruise control system will be described with reference to FIG. The normally open first brake switch BRK1 is connected to the input port PORT1 of the CPU 50, as in the above embodiment. Normally closed type second brake switch BRK2
Is provided in the energization path to the electromagnetic clutch 69 (corresponding to the actuator in the claims).

Further, in the ECU 75, the electromagnetic clutch 6
A transistor 76 with a diagnosis function is provided as a switch means for turning on / off the power supply to
The second brake switch BRK2 is connected to the output terminal OUT of the transistor 76. The input terminal IN of the transistor 76 is the output port XRC of the CPU 50.
Connected to L, and the diagnostic terminal DI of the transistor 76
The AG is connected to the input port PORT2 of the CPU 50.

This transistor 76 is turned off when the output of the output port XRCL of the CPU 50 is Lo, and the power supply to the electromagnetic clutch 69 is cut off. Transistor 7
The voltage levels of the output terminal OUT and the diagnosis terminal DIAG when the switch 6 is OFF are switched according to ON / OFF of the second brake switch BRK2 as shown in FIG. That is, when the second brake switch BRK2 is on, both the output terminal OUT and the diagnosis terminal DIAG of the transistor 76 become Lo, and when the second brake switch BRK2 is off, the output terminal OUT of the transistor 76. Both the diagnosis terminal DIAG and the diagnosis terminal DIAG become Hi.

Next, the failure mode and failure determination method of the first brake switch BRK1 and the second brake switch BRK2 will be described with reference to FIG. When the cruise main switch (not shown) is on and the two systems of brake switches BRK1 and BRK2 are normal, the input levels of the input ports PORT1 and PORT2 of the CPU 50 are always different voltages. That is, when the brake pedal is not depressed, the input port PORT1 is Hi and PORT2
Becomes Lo, and when the brake pedal is depressed, PORT1 becomes Lo and PORT2 becomes Hi.

Failures of the brake switches BRK1 and BRK2 include short-circuit failure of the first brake switch BRK1, open failure of the first brake switch BRK1, short failure of the second brake switch BRK2 and open of the second brake switch BRK2. There are four failure modes: failure. In any failure mode, the combination of the input levels of the input ports PORT1 and PORT2 is different from that in the normal state.

Utilizing this relationship, when the brake pedal is not depressed, the input port PORT1 is Hi and P
When ORT2 is Lo, it is determined to be normal, and when both voltage levels are the same, it is determined to be a failure. At this time, if both the input ports PORT1 and PORT2 are Lo, it is determined that the first brake switch BRK1 has a short circuit failure,
If both the input ports PORT1 and PORT2 are Hi, it is determined that the second brake switch BRK2 has an open failure.

When the brake pedal is depressed, the input port PORT1 is Lo and PORT2 is Hi.
When it is, it is determined to be normal, and when both voltage levels are the same, it is determined to be a failure. At this time, the input ports PORT1, P
If both ORT2 are Hi, it is determined that the first brake switch BRK1 has an open failure, and the input port PO
If both RT1 and PORT2 are Lo, it is determined that the second brake switch BRK2 has a short circuit failure.

In the two embodiments described above, the normally open type switch is used as the first brake switch BRK1, but this may be changed to the normally closed type switch.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an entire cruise control system in an embodiment of the present invention.

FIG. 2 is a block diagram showing a hardware configuration of an ECU.

FIG. 3 is a diagram showing a piping configuration of three electromagnetic valves for controlling negative pressure in a mechanical guard actuator.

FIG. 4 is a circuit diagram showing an electrical configuration of a control system of the cruise control system.

FIG. 5 is a flowchart showing a processing flow of a C / C mode setting processing routine.

FIG. 6 is a flowchart showing a processing flow of a C / C release routine.

FIG. 7 is a flowchart showing a processing flow of a mechanical guard drive routine.

FIG. 8 is a time chart showing an example of driving a mechanical guard during C / C.

FIG. 9 is a diagram illustrating a failure mode and a failure determination method of the first brake switch BRK1 and the second brake switch BRK2.

FIG. 10 is a flowchart showing a processing flow of a brake switch failure diagnosis routine (No. 1).

FIG. 11 is a flowchart showing a processing flow of a brake switch failure diagnosis routine (No. 2).

FIG. 12 is a diagram showing a schematic configuration of a cruise control system according to another embodiment of the present invention.

FIG. 13 is a circuit diagram showing an electrical configuration of a control system of the cruise control system.

FIG. 14 is a diagram for explaining the relationship between the voltage levels of the output terminal OUT and the diagnosis terminal DIAG and the ON / OFF state of the second brake switch BRK2 when the transistor with the diagnosis function is OFF.

FIG. 15 is a diagram illustrating a failure mode and a failure determination method of the first brake switch BRK1 and the second brake switch BRK2.

FIG. 16 is a circuit diagram showing a connection relationship between conventional two-system brake switches.

[Explanation of symbols]

12 ... Throttle valve, 14 ... Throttle actuator, 16 ... ECU (control means, failure diagnosis means), 2
0 ... Cruise control switch, 24 ... Mechanical guard mechanism, 25 ... Mechanical guard, 31 ... Negative pressure diaphragm type actuator, 33 ... Negative pressure side electromagnetic valve (VV), 3
4 ... Atmosphere side electromagnetic valve (VA), 35 ... Release electromagnetic valve (VR: actuator), 60 ... Cruise main switch, 66 ... C / C actuator, 67 ... Motor, 68 ... Control arm, 69 ... Electromagnetic clutch (actuator) ), 71 ... Negative pressure introduction path, 72 ... Atmosphere communication path, 75 ... ECU, 76 ... Transistor (switch means) with diagnosis function, BRK1 ... First brake switch, BRK2 ... Second brake switch, T
rR: transistor (switch means), TrV, TrA
... transistors.

Claims (4)

[Claims] 1. An actuator for switching a vehicle speed control between a normal control by a driver's accelerator operation and a constant speed traveling control for traveling at a constant speed at a set vehicle speed, and an automatic control of an opening of a throttle valve during the constant speed traveling control. The control means for releasing the constant-speed traveling control to switch to the normal control by cutting off the power supply to the actuator when the brake pedal is depressed during the constant-speed traveling control. In the constant-speed traveling device for a vehicle, the first and second brake switches that are switched on / off in conjunction with the depression operation of the brake pedal are provided, and the first brake switch outputs an on / off signal. The second brake switch is a normally-open or normally-closed switch that is input to the control means, and the second brake switch serves as a redundant system to connect to the actuator. A normally-closed type switch provided in an electric circuit, wherein the control unit includes a switch unit provided in an electric circuit to the actuator when the first brake switch is operated during constant speed traveling control. A means for releasing the constant-speed traveling control by turning off the power supply to the actuator to cut off the energization to the actuator; and an ON / OFF state of the first and second brake switches is monitored during the constant-speed traveling control and the ON / OFF state is monitored. A constant speed traveling device for a vehicle, comprising: failure diagnosis means for diagnosing whether or not each brake switch has a failure in a combination of OFF states. 2. The failure diagnosis means includes the first and second failure diagnosis means.
2. The vehicle constant-speed traveling device according to claim 1, wherein when the combination of the ON / OFF states of the brake switches is in the failure mode for a predetermined time or more, it is diagnosed that there is a failure. 3. The failure diagnosing means repeatedly performs the failure diagnosis, and finally diagnoses the failure as the result of the failure diagnosis is repeated a predetermined number of times. Or the constant speed traveling device for a vehicle according to 2. 4. The failure diagnosing means repeatedly performs failure diagnosis after diagnosing that there is a failure, and the combination of the on / off states of the first and second brake switches is in a normal state for a predetermined time or more. When the above is done, the diagnosis result of the previous failure is canceled.
A constant speed traveling device for a vehicle according to any one of 1.