JPH04138930A - Constant speed running control device - Google Patents

Abstract

PURPOSE:To prevent occurrence of a trouble, such as execution of speed control owing to failure in operation, such as fusion of a switching means, by turning off switching means so that a power source to a throttle drive means may be disconnected when speed control is not commanded. CONSTITUTION:A speed control means CPU turns on a switching means K when speed control is commanded by a command means SSW and energizes a throttle drive means 20 in the direction, in which a vehicle speed detected by car speed detecting means LSW and CPU coincides with a target speed, through drivers SD1 and SD2. The above constant speed control device monitors a voltage between the switching means K and the throttle drive means 20, and on/off of the switching means K is detected by means of an on/off detecting means 40 and the CPU. When speed control is not commanded, the starting of speed control is prohibited by a prohibiting means CPU in response to detection of on of the on/off detecting means 40 and the CPU.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention compares the running speed of a vehicle with a target speed, and opens a throttle valve in order to make the running speed equal to the target speed. The present invention relates to a constant speed cruise control device with closed drive, and particularly relates to a constant speed cruise control device having a failsafe device for constant speed travel.

(Prior Art) A constant speed cruise control device compares a traveling speed with a target speed, and when the former is low, drives the throttle valve to open, and when the former is high, drives the throttle valve to close.

The throttle valve is driven to open and close by a negative pressure actuator that expands and contracts a diaphragm using, for example, negative pressure in an intake manifold. By communicating the diaphragm internal space with the intake manifold, the diaphragm retracts and the throttle valve is driven to open, and by communicating with the atmosphere, the diaphragm expands and the throttle valve is driven to close (for example, Japanese Patent Laid-Open No. 62-68138 Public bulletin).

A ferrule safe device is used to control on/off of power to this negative pressure actuator.

Conventionally, this fail-safe device is provided with a latch means composed of, for example, a D-flip-flop, in addition to a microcomputer for constant speed running control, and the power supply to the negative pressure actuator is controlled according to the output state of the latch means. on/
Off control was being performed. This latch means is set by a command signal for instructing the start of constant speed driving,
It is reset by a cancel signal instructing the end of constant speed driving. When the latch means is set, power is turned on (supplied) to the negative pressure actuator, and when it is reset, it is turned off (cut off). These command signals and reset signals are input from command signal input means and cancel signal input means provided separately from the microcomputer.

On the other hand, when a command signal is input, the microcomputer controls the negative pressure actuator on/off, adjusts the throttle valve opening to control the vehicle to run at a constant speed so that the vehicle reaches the target speed, and when a cancel signal is input, the microcomputer controls the negative pressure actuator. That control had ended.

However, in the conventional constant speed cruise control device having the above-mentioned fail-safe device, the microcomputer does not monitor the output state of the launch means, so if the latch means malfunctions due to external noise, for example, the control of the microcomputer is activated. There are cases where the state and the output state of the latch means do not match, which causes a problem in that the fail-safe dual system is impaired.

In order to solve this problem, a device has been proposed in which a microcomputer monitors the output state of the latch means to make the output state of the latch means normal, thereby ensuring safe running of the vehicle (Japanese Patent Laid-Open No. 2-171347). Public bulletin).

(Problem M to be Solved by the Invention) In a constant speed cruise control device, according to safety standards, a system is adopted in which power is supplied to the negative pressure actuator via a relay so that the power is turned off when cancelled.

According to the device disclosed in Japanese Unexamined Patent Publication No. 2-171347, the microcomputer monitors the output state of the launch means, but does not monitor the transistor that is the relay for power supply. Power may be supplied to the negative pressure actuator even after constant speed driving control has ended, and safety is not sufficient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a constant speed cruise control device with improved safety.

[Structure of the invention]

(Means for Solving the Problems) A constant speed cruise control device of the present invention has a throttle drive means (5) connected to a throttle valve (5) of an engine on a vehicle.
20); Throttle drive means (20) and power supply (8T)
a switching means (K) inserted between; a driver (SDI,
5D2) ; Vehicle speed detection means (LS
W, CPU); instruction means (SSW) for instructing speed control;
); and when speed control is instructed by the instruction means (SSW), the switching means (K) is turned on and the vehicle speed detected by the vehicle speed detection means (LSW, CPU) is set in the direction that matches the target speed. Throttle drive means (2o
) is energized via the driver (SDI, 5D2). In a constant speed cruise control device comprising a speed control means (CPU); a switching means (K) and a throttle drive means (2o).
on/off detection means (40, CPU) for monitoring the voltage between and detecting on/off of the switching means (K);
and inhibiting means (CPU) for prohibiting the start of speed control in response to the ON detection of the on/off detection means (40, CPU) when the speed control is not instructed.

Note that the symbols in parentheses are corresponding elements in the embodiment described later.

(Operation) According to this, the prohibition means (CPU) is the instruction means (SS
on/off detection means (40, In response to detection of turning on the CPU (CPU), the start of speed control is prohibited.

In other words, when speed control is not instructed, the switching means (K) is turned off so as to cut off the power to the throttle driving means (20). )
There is no voltage between on/off detection means (4G, CPU)
Although the detection means (40, CP
When U) is detected to be on, the prohibition means (CPU) determines that the switching means (K) has an on failure, and prohibits energization of the throttle drive means (20).

Therefore, the safety of the system is improved because the problem of speed control being performed due to a failure such as fusion of the switching means (K) even though speed control is not in progress does not occur.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

(Example) FIG. 1 shows an outline of the configuration of an embodiment of the present invention.

In this embodiment, a microcomputer CPU is used to control the device.
is used. Power for this electric circuit is supplied from the on-board battery BT via a switch IGS linked to an ignition switch. Power converted into a stable voltage of 5V by the voltage stabilizing circuit VRG is applied to a logic circuit such as a microcomputer CPU.

BSW is a brake switch that is linked to the operation of a brake pedal (not shown), CSW is a clutch switch that is linked to the operation of a clutch pedal (not shown), and SSW is
The set switch BSW for commanding constant speed running is the resume switch for commanding restart of constant speed driving, and LSW is
This is a reed switch for detecting vehicle speed. A permanent magnet Mag connected to the speedometer cable is arranged near the reed switch LSW. LP is a stop lamp.

One end of the switch BSW is connected to the switch IGS via a fuse FS2, and the other end of the switch BSW is grounded via stop lamps L and P. Both ends of the switch BSW are connected to the input port P1 of the microcomputer CPU via the interface circuit IFC.
and connected to P2. In addition, switch csw,
ssw.

BSW and LSW are all grounded at one end, and the other end is connected to the input port of the microcomputer CPU via the interface circuit IFC. P4. P
5 and P6. Note that the input port P6 of the microcomputer CPU is an external interrupt input terminal.

Microcomputer CPU output ports P7 and P
8 have solenoid drivers SDI and SD, respectively.
Solenoids SL1 and SL2 are connected via 2. These solenoids SLI and SL2 operate as a control solenoid and a release solenoid for a negative pressure actuator, which will be described later, respectively.

A motor driver MD that energizes a drive motor M that drives a vacuum pump VP is connected to an output port P9 of the microcomputer CPU.

Additionally, the output photo 10 of the microcomputer CPU turns on/off a power supply relay K that supplies or cuts off power to the negative pressure actuator 20 and the drive motor M mentioned above.
A signal SRO is output as a drive signal to the relay drive circuit 30 that performs OFF control. The relay drive circuit 30 includes a resistor Ra.

It is composed of Rh and a transistor T1.

Furthermore, the input port P11 of the microcomputer CPU
is the digital signal VA output from the signal detection circuit 40.
is entered. This signal detection circuit 40 includes a resistor Rc
, Rd and a Zener diode D, and when the relay K is off (the state shown in Figure 1), or when the relay K
This circuit monitors the voltage between the negative pressure actuator 20 and the drive motor M and the relay when it is on, and outputs the corresponding digital signal VA to the microcomputer CPU. The stop switch 5TSW is a normally closed switch, and when the switch is opened in an emergency, the power to the negative pressure actuator 20 and the drive motor M can be cut off from the outside. .

FIG. 2 shows the configuration of the negative pressure actuator 20 shown in FIG. 1.

The housing 1 consists of two parts 1a, lb.

The diaphragm 2 is sandwiched between these two parts la and lb. A space surrounded by the diaphragm 2 and the housing 1a is a negative pressure chamber, and a space surrounded by the diaphragm 2 and the housing 1b communicates with the atmosphere. Reference numeral 3 denotes a compression coil spring inserted between the housing 1a and the diaphragm 2, which pushes the diaphragm 2 back to the position of the imaginary line when the pressure in the negative pressure chamber is close to atmospheric pressure.

A protrusion 4 fixed near the center of the diaphragm 2 is connected to a link of a throttle valve 5.

The housing 1a is provided with a negative pressure intake lower communicating with the intake manifold 6 and atmospheric air intakes 8 and 9.

10 is a negative pressure control valve, and 11 is a negative pressure release valve, both of which are fixed to the housing 1a.

The movable piece 12 of the negative pressure control valve 10 is tiltable about P as a fulcrum, and a tension coil spring 13 is connected to one end.
The other end faces the control lens SLI. Both ends of the movable piece 12 function as valve bodies, and in response to energization and de-energization of the solenoid SLI, they open the lower negative pressure intake, close the atmospheric intake 8 (as shown), or close the lower negative pressure intake. Air intake port 8 is opened.

Similarly to the negative pressure release valve 10, the movable piece 14. It has a bow-stretched coil spring 15 and a solenoid SL2, and the movable piece 14 closes (the illustrated state) or opens the air intake port 9.

In addition, a vacuum pump V, which is an external negative pressure source, is connected between the intake manifold 6 and the negative pressure intake lower communicating therewith.
The inlet of P is in communication. Vacuum pump vP is
Driven by motor M, suction pressure (negative pressure) is applied to the negative pressure intake lower. 18 is a check valve. Note that 16 is an accelerator pedal, and 17 is a tension coil spring.

FIG. 3 shows an outline of the control operation of the microcomputer CPU shown in FIG. 1.1. Figures 4 and 5.

6, 7, 8 and 9 show details of the subroutine or interrupt processing routine shown in FIG. 3.

See Figure 3. When the microcomputer CPU is powered on (Sl:S means a step or subroutine of a flowchart, and the number indicates a step number or subroutine number attached to the flowchart; hereinafter the same meaning), the microcomputer CPU performs initial settings, that is, boat state settings, Initial settings of the memory cell meter, etc. are performed (S2). When the microcomputer CPTJ completes the initial setting, the 83
The following process is repeatedly executed at approximately 50m5ec intervals.

In S3, the states of input boats P1 to P6 and pH are read. Then, it is checked whether S=1, that is, constant speed control processing to be described later is in progress (S3a). If the constant speed control process is not in progress, that is, when the relay drive circuit 30 shown in FIG. 1 turns off the power supply relay K (the state shown in FIG. 1), the drive signal SRO output from the microcomputer CPU is low. level and the signal detection circuit 40
The signal vP output from to the microcomputer CPU
Checks whether it is at L level (S3c). Also,
If constant speed control processing is in progress, that is, the relay drive circuit 30
turns on the power supply relay K, the drive signal SR
It is checked whether O is at H level and signal VP is at H level (S3b). Then, in step S3c, "5RO=L and VA=L" or in step S3b
If "5RO=H and VA=H" in step S4
However, in other cases, the process advances to step S8.
is set to 0 and cancel processing (S12) described below
will be held. Here, Table 1 shows the response when the process is normal, that is, the process proceeds to step S4.

Table 1 In other words, during constant speed control processing, signal SRO is at H level, which turns on the power supply relay and supplies power to negative pressure actuator 20 and drive motor M. At this time, the signal detection circuit 40 that monitors the voltage between the switching means (K) and the throttle drive means (20) detects that a certain voltage is present, and correspondingly, the signal is at H level under normal conditions. Pressure signal VA. but,
When the signal VA is at L level, the microcomputer CP
U determines that the power supply relay K has turned off and is out of order.

Furthermore, when the constant speed control process is not in progress, the signal SRO is set to L level and the power supply relay K is turned off. Therefore, since power is not supplied to the negative pressure actuator 20 and the drive motor M, the signal detection circuit 40 that monitors the voltage between the switching means (K) and the throttle drive means (20) detects that there is no voltage. Correspondingly, an L level signal VA is output during normal operation.

However, if the signal VA is at H level, the microcomputer CPU determines that the power supply relay K has turned on.

In this way, by monitoring the status of the power supply relay, it is possible to detect a failure in the relay, and in the event of a failure, cancellation is held (cancellation processing is executed in step 312).
do. In this configuration, a particular problem is an on-failure in the relay drive circuit 30 that generates a signal for on/off control of the power supply relay K. It is safe because the signal VA from the terminal remains at the H level and is held canceled.

Next, in steps 34, 35, and 36 or S7, it is checked whether any of the brake switch BSW, clutch switch CSW, set switch SSW, or resume switch R3W is on. Brake switch BS
If W is on (S4) or clutch switch C8W is on (S5), set register S to 0.38)
, if the set switch SSW is on (S6), the register S is set to 2 (39), and the resume switch R is turned on.
If 5W is on (S7), 3 is set in register S (S10).

Then, depending on the contents of register S (311), "cancellation processing J (312), r constant speed control processing" (
513), r set processing J (314) or [resume processing J (Sls), and returns to input port reading (S3). Thereafter, this operation is repeated in a loop.

Note that even if fuse FS2 is blown, switch BSW
The microcomputer CP
U determines that the switch BSW is turned on both when the input port P2 becomes a high level H and when the input port P1 becomes a low level L.

The external interrupt (S16) will be explained with reference to FIG.

In this example, the external interrupt occurs every time the vehicle speed detection reed switch LSW is turned on, that is, at the fall of the signal applied to the input capacitor P6.

When an external or external input occurs (S16), the contents of register R4 are incremented (1). As a result, in step 2, if the content of register R4 is less than 4, the process returns to the main routine, but if the content of register R4 is 4 or more, the microcomputer CPU reads the content of the internal hardware counter CN.

The counter CN always counts clock pulses of a predetermined period apart from the operation of the microcomputer CPU, but is cleared every four times an external interrupt occurs. Therefore, this counter CN has a reed switch LSW for vehicle speed detection.
A value corresponding to the time when four pulses are output is counted. A permanent magnet placed near the reed switch LSW has four poles, and when it rotates once, the reed switch LSW outputs four pulses. In other words, the counter CN measures the time it takes for the speedometer cable to rotate once.

Periodic data obtained by reading the contents of counter CN is 1.
The data is stored in register R6, and when the content of register R4 becomes 4 or more, the content of register R4 is cleared (3). Then, the vehicle speed is calculated from the periodic data stored in the register R5, and the result is stored in the register R8 (4).

When these processes are completed, the contents of the counter CN are cleared and restarted (5), and the process returns to the main routine.

Next, timer interrupt processing (S17) will be explained with reference to FIG. In this example, a hardware timer provided internally in the microcomputer CPU is used to generate a timer interrupt request at predetermined intervals. When the timer interrupt request occurs, timer interrupt processing (317) shown in FIG. 5 is executed.

In timer interrupt processing (317), register RA.

Increment RB (11). These registers are used as independent timers.

Every time the value of register RA exceeds the predetermined value NA (12),
The contents of register R1 are stored in register R2, and the contents of register RO are stored in register R1 (13). Since this process is performed every time the value of the register RA exceeds the predetermined value NA, the latest vehicle speed and the previously measured vehicle speed are stored in each register R2 and R1, respectively. Furthermore, the result of subtracting the value of register R2 from the value of register R1 is stored in register R3, and the contents of register RA are cleared to O (14). This process is performed periodically at predetermined time intervals determined by the value of NA. The contents of register R3 are used as acceleration data in the duty calculation described later.

Note that the register RB that is incremented in the timer interrupt process (317) is used as a timer for measuring the on-time or off-time of various switches. Also, the third
Although not shown in the figure, the brake switch BSW,
When the clutch switch CSW, set switch SSW, or resume switch R3W starts from the off state and changes to the on state, each clears the value of the register RB to 0. This allows the elapsed time since each switch was turned on to be determined.

Next, with reference to FIG. 6, [Cancel processing J (S 12
). In this process, the control solenoid SLI and the release solenoid SL2 are simply set to OFF (21.degree. 22), and the process returns to the main routine. In this manner, both the negative pressure control valve 10 and the negative pressure release valve 11 communicate the negative pressure chamber within the negative pressure actuator 20 with the atmosphere. Therefore, the negative pressure actuator 20
moves in the direction in which the throttle valve 5 does not open.

Therefore, if the power supply relay turns off as mentioned above,
If an on-failure or an on-failure in the relay drive circuit 300 occurs, this cancellation process is performed, thereby further improving the safety of the system.

Next, referring to FIG. 7, "Set processing J (S14)
Explain. When the set switch SSW is turned on, the release solenoid SL2 is first set to on (31
). Thereby, the negative pressure release valve 11 isolates the negative pressure chamber of the negative pressure actuator from the atmosphere. However, even in this state, the control solenoid SLI remains off, so the negative pressure control valve 10 communicates the negative pressure chamber of the negative pressure actuator with the atmosphere.

If the set switch SSW remains on (
32), then immediately return to the main routine. Therefore, even if the vehicle is in a predetermined running state, if the driver takes his foot off the accelerator pedal 16, the vehicle speed will gradually decrease. When the set switch SSW changes from on to off (
32), the contents of the register R8 at that time, that is, the current vehicle speed, are stored in the vehicle speed memory RM (33), and 1 is set in the register S (34). When register S is set to 1, the next loop process starts with “constant speed control process J”, which will be described later.
(513) is executed.

Next, with reference to FIG. 8, "Resume processing J (315)"
Explain. When resume switch R3W is turned on,
First, set release solenoid SL2 to ON (4
1). Thereby, the negative pressure release valve 11 isolates the negative pressure chamber of the negative pressure actuator from the atmosphere. Next, check for overflow of the resume timer (42). Note that the resume timer is a register RB that is cleared when the resume switch R3W is turned on for the first time. If there is no overflow, return to the main routine.

When the resume timer overflows (43), the control solenoid SLI should be set to the on state (44)
, stores the contents of register R8 in vehicle speed memory RM (4
5). When the control solenoid SL1 is maintained in the on state, the negative pressure control valve 10 is connected to the negative pressure chamber of the negative pressure actuator 20. Therefore, in this state, the state of the negative pressure actuator gradually changes in the direction of opening the throttle valve 5, and the vehicle speed gradually increases. Resume switch R
When 3W is turned off (42), the register S is set to 1 (46), and in the next loop process, the process proceeds to constant speed control process J (S13).

If the resume switch R5W is turned off before the resume timer overflows, the vehicle speed previously stored in the vehicle speed memory RM is read and the vehicle starts running at a constant speed. However, if the resume timer overflows, the vehicle speed Since the contents of the memory RM are updated to the current vehicle speed, the vehicle enters constant speed driving at the current vehicle speed.

[Constant speed control processing J (513)] will be explained with reference to FIG. When it comes to Denity control timing (51),
The output duty DV is calculated by constant speed control duty calculation (52). Then, when the output duty DV is set (53), a predetermined period (50ms
ec), the solenoid SLI of the negative pressure control valve 10 is duty-controlled.

Then, the negative pressure is detected and the motor M is controlled on/off so that the negative pressure falls within a certain range (54).

In step 55, the phase within the duty control period is checked using register RB. and register RB
If the content of is from 0 to output duty DV, it is (55)
Set control solenoid SL1 to ON56
), and from the output duty DV to DVmax (duty control period) (58), the control solenoid SLI is set to OFF (57). In step 58,
When RB exceeds DVmax, that is, each time one cycle of duty control ends, the contents of register RB are cleared 59) and time measurement for the next cycle is started. Timing is performed by timer interrupt (317) in FIG. Therefore, when the control solenoid SLI is controlled on/off according to the calculated output duty DV, the negative pressure control valve 10 connects the negative pressure chamber of the negative pressure actuator 20 alternately to the negative pressure system and the atmosphere. . As a result, the pressure in the negative pressure chamber within the negative pressure actuator is adjusted to a value corresponding to the duty DV, and the opening degree of the throttle valve 5 is determined accordingly.

Note that in this embodiment, power supply/cutoff to the negative pressure actuator 20 and the drive motor M was performed by the power supply relay K, but a transistor may be used in place of the relay K.

〔Effect of the invention〕

As described above, according to the present invention, when speed control is not instructed by the instruction means (SSW), the prohibition means (CPU) controls the switching means (K) and the throttle drive means (20
) and turns on/off the switching means (K).
In response to the ON detection of the ON/OFF detection means (40° CPU) that detects OFF, the start of speed control is prohibited.

In other words, when speed control is not instructed, the switching means (K) is turned off so as to cut off the power to the throttle driving means (20). )
There is no voltage between on/off detection means (40, CPU)
Although the detection means (40, CP
When U) is detected to be on, the prohibition means (CPU) determines that the switching means (K) has an on failure, and prohibits energization of the throttle drive means (20).

Therefore, the safety of the system is improved because the problem of speed control being performed due to a failure such as fusion of the switching means (K) even though speed control is not in progress does not occur.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an electric control circuit of a constant speed cruise control device according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing the negative pressure actuator 20 included in the device shown in FIG. FIG. 3 is a flowchart showing the control operation of the microcomputer CPU shown in FIG. 4, FIG. 5, FIG. 6, FIG. 7, FIG. 8, and FIG. 9 are flowcharts showing the subroutine and interrupt processing shown in FIG. 3. 1, la, lb: Housing 2 Diaphragm 3: Compression coil spring 4 protrusions 5゛ Throttle valve (throttle valve) 6: Intake manifold 7: Negative pressure intake 8, 9: Atmospheric intake 10
: Negative pressure control valve 11 Atmospheric release valve 12.1
4: Movable piece 13.15.17 Tension coil spring 16, accelerator pedal 18. Check valve 20: Negative pressure actuator (throttle drive means) 30
: Relay drive circuit 40゛Signal detection circuit (on/off detection means) K relay (
Switching means) LSW Reet Switch (vehicle speed detection means) Mag rotating permanent magnet CPU: Microcomputer (vehicle speed detection means, speed control means, on/off detection means,
Prohibition means) LP stop lamp BSW brake switch C3W clutch switch SSW: Set switch (instruction means) R5W resume switch 5TSW stop switch FSI, FS2: Fuse BT battery (power supply) VRG voltage stabilization circuit IFC: Interface circuit SDI, SD2 solenoid driver(
Driver) SLI, SL2: Solenoid P
Fulcrum MD motor driver M motor VP vacuum bomb Fig. 4 Fig. 5 Fig. 9

Claims (1)

[Claims] Throttle driving means coupled to a throttle valve of an engine on a vehicle; switching means interposed between the throttle driving means and a power source; a driver for energizing the throttle driving means; Vehicle speed detection means for detecting; instruction means for instructing speed control; and when the instruction means instructs speed control, the switching means is turned on and the speed of the vehicle detected by the vehicle speed detection means matches the target speed. A speed control device that biases the throttle drive device in a direction through the driver, wherein a voltage between the switching device and the throttle drive device is monitored to control whether the switching device is turned on or off. The vehicle is characterized by comprising: on/off detection means for detecting off; and prohibition means for prohibiting the start of speed control in response to the on detection of the on/off detection means when the speed control is not instructed. Constant speed driving control device.