JPH0378287B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a constant speed traveling device for a vehicle, and more particularly to a constant speed traveling device using a pneumatic actuator as an actuator for adjusting the throttle valve opening. It is something.

[Prior art]

In a constant speed traveling device using a pneumatic actuator (for example, disclosed in Japanese Patent Application Laid-Open No. 79227/1983), a diaphragm is operated by the air pressure in the pressure chamber of the actuator, and the speed is controlled by the operation of the diaphragm. Adjust the opening of the tutle valve. Therefore, by controlling the negative pressure and atmospheric pressure introduced into the pressure chamber, the vehicle speed can be controlled to be equal to the set vehicle speed. In other words,
When the pressure (absolute pressure) in the pressure chamber decreases due to an increase in the amount of negative pressure introduced into the pressure chamber, the diaphragm is deformed greatly and the opening of the throttle valve is increased; The pressure in the chamber increases and the opening degree of the throttle valve is reduced.

Conventionally, in a constant speed traveling system using a pneumatic actuator, the negative pressure supply source is the intake pipe negative pressure of the engine. When the vehicle is running on a flat road, the load on the engine is relatively small (that is, the throttle valve opening is relatively small), so the intake pipe negative pressure is large (low in terms of absolute pressure), and the actuator Necessary and sufficient negative pressure is supplied to the pressure chamber, and control to maintain the vehicle speed at the set vehicle speed can be performed normally. However, when the vehicle approaches an uphill road while driving at a constant speed, the load on the engine increases (that is, the throttle valve opening increases), so the intake pipe negative pressure decreases. , the necessary negative pressure cannot be supplied to the pressure chamber of the actuator. Therefore, even when the vehicle speed becomes lower than the set vehicle speed and the opening degree of the throttle valve must be increased, sufficient negative pressure is not supplied to the pressure chamber, making it impossible to lower the pressure in the pressure chamber. However, the opening of the throttle valve cannot be increased. As a result, it becomes impossible to maintain the set vehicle speed on an uphill road.

In addition, in recent years, some vehicles have turbochargers in their engines, and in such cases, even if you are not driving uphill, when the turbocharger is activated, the pressure in the intake pipe increases, creating positive pressure instead of negative pressure. As a result, sufficient negative pressure cannot be supplied to the pressure chamber of the actuator, and the vehicle may not be able to travel while maintaining the set vehicle speed normally.

To solve this problem, we installed a new vacuum tank as a constant speed running device that allows the actuator to operate normally regardless of the vehicle's driving condition.
In addition to storing negative pressure in the intake pipe in this vacuum tank, when the negative pressure in the vacuum tank becomes small, the vacuum pump is used to increase the negative pressure in the vacuum tank. Therefore, a system has been considered (not yet known) that can supply the necessary and sufficient negative pressure to the pressure chamber of the actuator at any time.

However, this system has the problem of requiring a heavy and large vacuum tank.

[Purpose of the invention]

In view of these conventional problems, an object of the present invention is to accurately operate the vacuum pump when it is necessary to supply a large amount of negative pressure to the pressure chamber of the actuator. The object of the present invention is to constantly supply necessary and sufficient negative pressure to the pressure chamber of the actuator without requiring a vacuum tank.

[Structure of the invention]

The first configuration of the present invention to achieve this purpose is as follows.
This will be explained with reference to FIGS.

FIG. 1 is a claim correspondence diagram of the first invention.
A constant speed traveling device equipped with a pneumatic actuator 10 can be switched between a driving state and a stopped state. Vacuum pump 30 that supplies negative pressure
will be established. The determining means determines whether the vehicle speed is lower than the set vehicle speed and the difference between the vehicle speed and the set vehicle speed is greater than a predetermined value.The driving means determines whether or not the vehicle speed is in the low speed state by the determining means. The Yum pump 30 is driven.

Therefore, when the vehicle speed becomes lower than the set vehicle speed and enters a low speed state, the vacuum pump 30 is driven by the driving means, and the negative pressure generated by the vacuum pump 30 compensates for the negative pressure in the intake pipe.

FIG. 2 is a claim correspondence diagram of the second invention.
A constant speed traveling device equipped with a pneumatic actuator 10 can be switched between a driving state and a stopped state. Vacuum pump 30 that supplies negative pressure
will be established. The first determination means determines whether the vehicle is in a low-speed state where the vehicle speed is lower than the set vehicle speed and the difference between the vehicle speed and the set vehicle speed is greater than a predetermined value. Further, a vacuum switch is provided to detect the negative pressure in the intake pipe of the engine, and detects when the negative pressure in the intake pipe has become a low negative pressure state closer to atmospheric pressure than a predetermined negative pressure. The second determining means determines whether the vacuum switch detects a low negative pressure state. and,
The driving means drives the vacuum pump 30 when the first determining means determines that the speed is low, or when the second determining means determines that the low negative pressure is present.

Therefore, when the vehicle speed becomes lower than the set vehicle speed and enters a low speed state, the driving means drives the vacuum pump 30, and if the intake pipe negative pressure is small, the vacuum switch detects it and also reduces the vacuum pump 30. The Yum pump 30 is driven.

FIG. 3 is a claim correspondence diagram of the third invention,
This invention further includes a timer means in addition to the second invention described above. The timer means continues driving the vacuum pump 30 by the driving means for a certain period of time.

Therefore, when the vacuum pump 30 is driven as in the second invention, it continues for a certain period of time.

FIG. 4 is a claim correspondence diagram of the fourth invention.
The constant speed traveling device is equipped with a pneumatic actuator 10 and is configured to increase the vehicle speed along with the set vehicle speed in response to an acceleration operation, and is switchable between a driving state and a stopped state.
2 Downstream intake pipe (surge tank 23) and pressure chamber 1
A vacuum pump 30 is provided for supplying negative pressure to a communication path that communicates with 03. The determining means determines whether the vehicle is in a low speed state where the vehicle speed is lower than the set vehicle speed and the difference between the vehicle speed and the set vehicle speed is greater than a predetermined value. Further, the acceleration operation detection means detects that an acceleration operation is being performed to increase the vehicle speed together with the set vehicle speed. In the drive means, when the determination means determines that the speed is low, or when the acceleration operation detection means detects an acceleration operation,
The vacuum pump 30 is driven.

Therefore, when the vehicle speed becomes lower than the set vehicle speed and enters a low speed state, the driving means drives the vacuum pump 30, and also when an acceleration operation is performed, the vacuum pump 30 is driven.

〔Effect of the invention〕

According to the present invention, even if the negative pressure in the intake pipe becomes small due to an operating condition in which the throttle valve is opened to a large degree or the operation of a turbocharger, etc., and it becomes difficult to maintain the current vehicle speed at the set vehicle speed, the vehicle speed When the pressure decreases, the vacuum pump is activated, and the negative pressure necessary to increase the vehicle speed is supplied to the pressure chamber of the actuator.

Therefore, regardless of the operating state of the vehicle, the negative pressure necessary for operating the actuator is supplied, and the constant speed traveling device can be operated normally. Moreover,
When it is necessary to supply a large amount of negative pressure to the pressure chamber of the actuator, the vacuum pump is activated accurately, so the necessary negative pressure is always secured without setting a vacuum tank, eliminating the need for a vacuum tank. This has the effect of reducing the weight and space occupied by the constant speed traveling device.

Further, according to the second invention, when a relatively large amount of negative pressure is required, such as in a low speed state detected by the first determination means, the vacuum pump is unconditionally driven to ensure the necessary negative pressure. However, in a low negative pressure state detected by the second determination means, that is, when the intake pipe negative pressure is small, the vacuum pump is activated to supply the intake pipe regardless of the amount of negative pressure required. Secure negative pressure instead. Therefore, a reduction in vehicle speed can be prevented, and the vacuum pump can be operated as needed without waste.

According to the third invention, once the vacuum pump is activated, the operation of the vacuum pump is continued for a certain period of time, so that sufficient negative pressure is ensured and the activation and stopping of the vacuum pump are repeated. can be prevented, and the life of the vacuum pump can be improved.

Furthermore, according to the fourth invention, even when an acceleration operation is performed in the constant speed traveling device, the vacuum pump is operated continuously during the acceleration operation, so that the large amount of water required for the acceleration operation is Negative pressure can be ensured, allowing rapid acceleration.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 is a schematic configuration diagram of one embodiment, in which 10 is a pneumatic actuator, 21 is an engine, 22 is a throttle valve, 30 is a vacuum pump, 40 is a vacuum switch, and 60 is a constant speed The control circuits of the traveling devices are shown respectively.

The pneumatic actuator 10 is a known one, and the pressure chamber 1 is
03 is formed. Diaphragm 102 is connected to throttle valve 22 by link 24, and negative pressure and atmospheric pressure are introduced into pressure chamber 103 through ports 111-113. Pressure chamber 1
Negative pressure and atmospheric pressure are introduced into pressure chamber 10
When the pressure (absolute pressure, the same applies hereinafter) in No. 3 is adjusted to a predetermined pressure, the opening degree of the throttle valve 22 is set to the predetermined opening degree, and when the pressure in the pressure chamber 103 becomes lower than the predetermined pressure, the throttle valve 22 is The opening degree becomes larger than the predetermined opening degree, and conversely, when the pressure in the pressure chamber 103 increases, the opening degree of the throttle valve 22 becomes smaller. When the pressure in the pressure chamber 103 reaches atmospheric pressure, the throttle valve 22 opens as shown in the figure.
is fully closed. For this purpose, although not shown, a spring force is applied to the diaphragm 102, and the diaphragm 102 is always biased in a direction to expand the volume of the pressure chamber 103.

Negative pressure is introduced from port 111 as will be described later, and atmospheric pressure is introduced from ports 112 and 113. Each of these ports 111 to 113 is opened and closed by a control valve 122 and a release valve 132, and the control valve 122 is connected to the fulcrum 12.
The release valve 132 swings around a fulcrum 133 to selectively open and close the ports 113. The control valve 122 is energized to open the port 111 and close the port 112 when the control coil 121 is energized, and the release valve 132 is energized to open the port 112 when the release coil 131 is energized.
13 is now closed. These control coils 121 and release coils 131 are connected to the control circuit 6
The energization is controlled by the output signal from 0.

The port 111 is connected to the surge tank 23, which is a part of the intake pipe, via communication passages 76 and 75. The surge tank 23 is the turbo charger 2
5. Together with the throttle body 27 and intake manifold 26, it forms the intake path of the engine 21, and when the turbocharger 25 is not operating, the inside of the surge tank 23 becomes negative pressure due to the intake action of the engine 21. There is. This negative pressure is guided to port 111 via communication passages 75 and 76. However, when the turbocharger 25 operates, supercharging is performed, so if this supercharging pressure is high, the inside of the surge tank 23 is not a negative pressure but a positive pressure higher than atmospheric pressure. Therefore, at this time,
Negative pressure is no longer supplied to port 111. Therefore, a vacuum pump 30 is provided in the middle of the communication paths 75 and 76.

The vacuum pump 30 is a known one,
A pump chamber 303 is formed by the casing 301 and a diaphragm 302 provided therein, and the chamber 3 is communicated with the pump chamber 303.
04 and 305 are formed, and further communicated with the chamber 305 to form a chamber 306. A check valve 311 is provided between the pump chamber 303 and the chamber 304, and a check valve 312 is provided between the pump chamber 303 and the chamber 305, and a check valve 312 is provided between the pump chamber 303 and the chamber 305.
A check valve 313 is provided between each of the two terminals 6 and 6. Check valve 311 allows air to flow only from pump chamber 303 to chamber 304, check valve 312 allows air to flow only from chamber 305 to pump chamber 303, and check valve 313 allows air to flow only from chamber 305 to chamber 306. Flow through. The chamber 304 is then opened to the atmosphere,
The chamber 305 communicates with the communication path 76, and the chamber 306
is communicated with the communication path 75.

In addition, the vacuum pump 30 has a motor 320
When the armature coil 321 is energized, the motor 320 rotates a rotor (not shown), and the rotational output is taken out from an output shaft 331 integrated with the rotor. The output shaft 331 of the motor 320 has an eccentric cam 333 coupled to its tip, and when the output shaft 331 rotates as shown by the arrow, the rod 332 slidingly in contact with the eccentric cam 333 moves as shown by the arrow. make it vibrate. The opposite side of the rod 332 from the eccentric cam 333 is connected to the center of the diaphragm 302, and when the rod 332 is vibrated, the diaphragm 302 is also vibrated to reduce or expand the volume of the pump chamber 303. repeat. Although not shown, a spring force is applied to the diaphragm 302 in a direction to expand the volume of the pump chamber 303. When the diaphragm 302 vibrates and the volume of the pump chamber 303 is contracted or expanded, when the diaphragm 302 is contracted, the air in the pump chamber 303 is discharged to the chamber 304 via the check valve 311, and when the pump chamber 303 is expanded, Air from the chamber 305 is sucked into the pump chamber 303 through the check valve 312.
Therefore, by repeating this operation, negative pressure is supplied into the chamber 305.
As mentioned above, the chamber 305 is in communication with the chamber 306, but since the check valve 313 is provided between the two, the negative pressure generated in the chamber 305 is
The surge tank 2 is connected via the chamber 306 and the communication path 75.
Although the negative pressure is not supplied to the chamber 305, the negative pressure that is supplied to the chamber 306 from the surge tank 23 is also supplied to the chamber 305.

In addition, the communication path 75 includes a vacuum switch 4.
0 is connected. Bakyume Switch 40
is a well-known one, and has a casing 41 and a diaphragm 42 provided therein.
Two chambers 45 and 46 are formed, one chamber 45 communicating with the communication path 75 and the other chamber 46 being open to the atmosphere. On the chamber 46 side of the diaphragm 42,
A contact 43 is fixed, and a contact 44 is fixed to the chamber 46 side of the casing 41 so as to face the contact 43. Also, diaphragm 4
2 has a spring 47 inserted between it and the inner wall of the casing 41 to constantly bias the diaphragm 42 so as to reduce the volume of the chamber 46. Therefore, the negative pressure introduced into the chamber 45 from the communication passage 75 is small (high in terms of absolute pressure, the same applies hereinafter).
, both contacts 43 and 44 come into contact with each other due to the bias force of the spring 47, and when the negative pressure in the chamber 45 is large (low in terms of absolute pressure, the same applies hereinafter), the diaphragm 4
2 is deformed to reduce the volume of the chamber 45, and both contacts 43 and 44 are separated. Contact 43 is grounded, and contact 44 is connected to one input terminal of control circuit 60.

The control circuit 60 includes an ignition switch 72
It is connected to the in-vehicle battery 71 via
As input signals, signals from the vehicle speed sensor 51, main switch 52, control switch 53, and cancel switch 54 are input to the control circuit 60.

The vehicle speed sensor 51 consists of a reed switch 511 and a rotor magnet 512. Since the rotor magnet 512 rotates at a rotation speed proportional to the axle, the reed switch 511 placed under the influence of the magnetic field of the rotor magnet 512, It is turned on and off at a frequency proportional to the vehicle speed.

The main switch 52 is a switch that can be turned on and off at will by the occupant. When turned on, the main switch 52 transmits a voltage signal supplied from the battery 71 via the ignition switch 72 to the control circuit 60.
Enter. In addition, the control switch 53
has one movable contact 533 and two fixed contacts 53
The movable contact 533 and fixed contact 534 constitute a set switch 531, and the movable contact 533 and fixed contact 535 constitute a resume switch 532. The set switch 531 and the resume switch 532 are momentary type switches that are turned on when arbitrarily operated by the occupant, and are always turned off when the operating force is released. Movable contact 533
is grounded, and both switches 531 and 532
When both are turned on, a ground signal is input to the control circuit 60.

Furthermore, the cancel switch 54 consists of three switches, one is a stop lamp switch 541 that is turned on when the brake pedal is depressed, and one is a parking lamp switch 541 that is turned on when the parking brake is operated. One is the clutch switch 5, which is turned on when the clutch pedal is depressed.
It is 43. If the transmission is an automatic transmission, the clutch switch 543 is replaced by a neutral start switch that is turned on when the shift lever is operated to the neutral position or the parking position. stop lamp switch 54
1 is connected between a stop lamp 73 and a battery 71 as is well known, and a voltage signal between the stop lamp switch 541 and the stop lamp 73 is input to the control circuit 60. Also,
As is well known, the parking brake switch 542 is connected to the battery 71 via the parking brake lamp 74 and the ignition switch 72.
A voltage signal between the parking brake switch 542 and the parking brake switch 542 is input to the control circuit 60. Furthermore, clutch switch 543 inputs a ground signal to control circuit 60 when turned on. Incidentally, although the explanation is omitted, each circuit connected to the battery 71 is provided with a fuse for interrupting overcurrent.

Next, the configuration of the control circuit 60 will be explained with reference to FIG. The control circuit 60 is mainly composed of a microcomputer, and the microcomputer is a microprocessor (MPU) as is known in the art.
611, read only memory (ROM) 612,
It has a random access memory (RAM) 613, an input port 615, and output ports 616 and 617, which are connected to each other by a common bus 618. The microcomputer also has a clock generator 614, which supplies the MPU 611 with a clock signal for operating the MPU 611, and also supplies the control circuit 611 with a clock signal for operating the MPU 611.
A predetermined clock signal is supplied to each part in 0.

In addition, in the control circuit 60, the control coil 12
Set-reset type flip-flop 624, down counter 62 for forming an output signal to 1
3. AND circuit 625, set-reset type flip-flop 629 for forming an output signal to the release coil 131, set-reset type flip-flop 622 for forming an output signal to the armature coil 321 of the vacuum pump 30, and performs impedance conversion. Batsuhua 626-62 for
8. Furthermore, it has a constant voltage circuit 621 for supplying constant voltage to each part in the control circuit 60.

Signals are input to the input port 615 from the vehicle speed sensor 51, main switch 52, set switch 531, resume switch 532, cancel switch 54, and vacuum switch 40, and other signals from the vehicle speed sensor 51 are as follows.
The data is taken into the MPU 611 in response to a request from the MPU 611. On the other hand, when the pulse signal from the vehicle speed sensor 51 is input to the input port 615, an interrupt request is made to the MPU 611, and the ROM
A known vehicle speed calculation processing routine among the programs stored in advance at 612 is activated. In the vehicle speed calculation processing routine, the interval between pulse signals generated from the vehicle speed sensor 51 is measured, and the reciprocal of the measurement time is calculated to obtain the vehicle speed. The obtained vehicle speed data is
It is stored at a predetermined address within the RAM 613.

Data regarding the energization time of the control coil 121 is output from the MPU 611 to the output port 616 , and the output data is output from the output port 616 to the down counter 623 . The down counter 623 uses the data output from the output port 616 as a preset value and counts it down in response to the clock signal from the clock generator 614. When the preset value becomes "0" as a result of down-counting, a count completion signal is input to the reset input terminal R of the flip-flop 624. Set input terminal S of flip-flop 624
A clock signal from a clock generator 614 is input to the clock signal. Here, flip-flop 6
The clock signal input to the set input terminal S of 24 is, for example, a 10 Hz signal, and the clock signal input to the down counter 623 is a 1 KHz signal. In addition, the down counter 62 is used as the energization time of the control coil 121 from the output port 616.
The maximum value of data output to 3 is 100.

Flip-flop 624 has a set input terminal S
A high level signal is output from the output terminal Q from when the signal is input to the reset input terminal R until the signal is input from the reset input terminal R. flipflop 624
The output signal is supplied to the control coil 121 via an AND circuit 625 and a buffer 626.
Therefore, as mentioned above, if the clock signal to the set input terminal S of the flip-flop 624 is 10 Hz and the clock signal to the down counter 623 is 1 KHz, the duty ratio of the control coil 121 is controlled at a period of 100 milliseconds. If the data output from output port 616 is 50, the duty ratio is 50%.
70 means 70%.

The output port 617 outputs an on signal and an off signal for the release coil 131 and an on signal and an off signal for the vacuum pump 30, respectively. The ON signal of the release coil 131 is input to the set input terminal S of the flip-flop 629, and the OFF signal is input to the reset input terminal R of the flip-flop 629. And flip-flop 62
The output terminal Q of the circuit 9 outputs a signal that is at a high level from when the signal is input to the set input terminal S until when the signal is input to the reset input terminal R. This signal is input to the AND circuit 625 and is also supplied to the release coil 131 via the buffer 627. Also, vacuum pump 3
An on signal of 0 is input to the set input terminal S of flip-flop 622, and an off signal is input to the reset input terminal R of flip-flop 622. Flip-flop 622 has a set input terminal S
Since a high level signal is output from the output terminal Q after the signal is input to the reset input terminal R until the signal is input to the reset input terminal R, the back The armature coil 321 of the vacuum pump 30 is energized via the buffer 628, and the vacuum pump 30 is activated.

7 to 10 show a part of the program stored in the ROM 612, and the operation of the above-described embodiment will be explained below according to these flowcharts.

7A to 7C are routines that are activated at predetermined intervals, for example, every 100 milliseconds, and this routine is a constant speed running control routine. When this routine is started, first, in step 201, it is determined whether the main switch 52 is turned on. If the main switch 52 is turned on, in step 202, the RAM 6
The current vehicle speed V stored in a predetermined location of 13 is taken in, and the upper limit value, for example, 136 km/h, and the lower limit value, for example, 48 km/h of the vehicle speed V, which are stored in advance in the ROM 612, are read into the MPU 611. It is determined whether the current vehicle speed V is between an upper limit value and a lower limit value. If the main switch 52 is not on, or if the current vehicle speed V is not between the upper limit value and the lower limit value, in step 203, "0" is stored in a predetermined address of the RAM 613 where the set vehicle speed Vset is to be stored. Then, in step 205, cancel processing, which will be described later, is performed. In other words,
If the vehicle speed V is not between the upper limit value and the lower limit value, it is treated as if the main switch 52 is not turned on.

On the other hand, if the current vehicle speed V is between the above upper limit and lower limit, in step 204 it is determined whether any of the cancel switches 54 are on. Either cancel switch 54
If the set switch 531 is not turned on, it is determined in step 207 whether or not the set switch 531 is currently turned on. Currently, set switch 5
If 31 is turned on, the step
In steps 205 to 211, a timer counter Ct, which will be described later, is cleared and a signal for turning off the vacuum pump 30 is output from the output port 617, and
Performs coasting processing, which will be described later. And step
At 211, the set switch flag SSF is set to remember that the set switch 531 has been turned on.
is set, and the processing of this routine ends.

At step 207, if the set switch 531 is not currently turned on, the step
At step 212, it is determined whether or not the set switch 531 was on in the previous processing cycle by determining whether or not the set switch flag SSF is set. If the set switch flag SSF is set, then in steps 230 to 250, processing during setting, VP processing, and processing during setting are executed.

The setting process is as shown in FIG. 8. First, in step 231, the vehicle speed V stored in the RAM 613 as vehicle speed data is
is stored at a predetermined location in the RAM 613 as the set vehicle speed Vset. Next, in step 232, a set flag STF is set to remember that the constant speed cruise control process has started, and a set switch flag SSF and a resume flag RSF, which will be described later, are reset. Then, in step 233, the output signal from the output port 616 is set to Vc as K ₁ ×
Obtained by Vset. Here, K ₁ is a constant.
Furthermore, in step 234, an ON signal for the release coil 131 is output from the output port 617, the flip-flop 629 is set, and a high level signal is output from the output terminal Q thereof. For this reason,
The release coil 131 is energized, and the release valve 132 is
Close port 113.

When the above-mentioned set-time processing 230 is completed, VP processing is performed in step 240.

The VP processing is as shown in FIG. 9. First, in step 241, the timer counter is
It is determined whether Ct has become "0", and if it is "0", an affirmative decision is made in step 241, and step 242 shows that the deviation ΔV between the set vehicle speed Vset and the current vehicle speed V is Vset - It is determined by V. Next, in step 243, it is determined whether the deviation ΔV is larger than the first predetermined value X, and in step 244, it is determined whether the deviation ΔV is larger than "0" (second predetermined value). be done. now,
If the set vehicle speed Vset and vehicle speed V match and the deviation ΔV is "0", negative judgments are made in both steps 243 and 244, and the process proceeds to step 248, where:
Vacuum pump 30 off signal output port 6
Output from 17. Therefore, flip-flop 6
A signal is input to the reset input terminal R of the flip-flop 622, and the flip-flop 622 is reset.No signal is output from the output terminal Q of the flip-flop 622, and the armature coil 3
21 is not energized. Therefore, the vacuum pump 30 is not operated.

The processing during setting is as shown in FIG. 10, and in step 251, Vc is determined as the output signal from the output port 616 by Vc+K ₂ ×ΔV. Here, K ₂ is a constant, but now,
If the deviation ΔV is "0", Vc is not changed.
Then, in step 252, the output port 61
Output Vc from 6. Vc from output port 616
When this value is output, the down counter 62
For example, 1K
It is counted down by a Hz clock signal. When the down count is completed, the flip-flop 62
A signal is input to the reset input terminal R of 4, and the flip-flop 624 is reset. Since the flip-flop 624 is set by inputting a clock signal to the set input terminal S in synchronization with the activation of the routine, the output terminal Q outputs a signal proportional to the signal Vc output from the output port 616. A signal with a time width (duty ratio) is output. As mentioned above, flip-flop 629
is already generating a high level signal, so
When a signal is output from the flip-flop 624, the signal is sent to the AND circuit 625 and the buffer 62.
6 to the control coil 121, and the signal
Control coil 121 is energized for a time proportional to Vc, during which time port 111 is energized by control valve 122.
is opened and port 112 is closed. As a result, negative pressure is introduced into the pressure chamber 103 of the actuator 10, and constant speed running control is started.

After that, unless one of the main switch 52, set switch 531, resume switch 532, or cancel switch 54 is operated, the main switch 52 is turned on and the set switch 53 is turned on.
1. The cancel switch 54 and the resume switch 532 are all off, and the set flag is
Since STF is set and the set switch flag SSF is reset, each time the constant speed cruise control routine is executed every 100 milliseconds, step 201,
Proceeding to steps 202, 204, 207, 212, 213, and 214, the VP processing at step 240 and the during-setting processing at step 250 are repeatedly executed. Therefore, in VP processing,
As shown in FIG. 9, a process is performed to output an ON signal or an OFF signal for the vacuum pump 30 from the output port 617 according to the value of the deviation ΔV, and in the setting process, as shown in FIG. 10, Vc+K ₂ × ΔV
output port 6 according to the deviation ΔV according to the calculation formula
Correction processing is performed on the output signal Vc from 16.

To explain the VP processing at this time in detail, the deviation ΔV is calculated in step 242, and if the deviation ΔV is "0" or negative, the steps 243 and 242 are performed.
Since both of the steps 244 and 244 are negative, an off signal for the vacuum pump 30 is output in step 248, and the vacuum pump 30 is still not operated.
Furthermore, when the deviation ΔV is greater than "0" and smaller than the predetermined value If the vacuum switch 40 is not turned on, the vacuum pump 30 will not be activated by the process in step 248, and the surge tank 2 will be turned on.
If the negative pressure in step 3 is small and the vacuum switch 40 is turned on, an affirmative determination is made in step 245, and the process proceeds to steps 246 and 247, where it is determined that the vacuum pump 30 is operated for T seconds. Become. In other words, in step 246, the timer counter
A value corresponding to T seconds is set to Ct, and the step
At 247, the ON signal of the vacuum pump 30 is input from the output port 617 to the set input terminal S of the flip-flop 622. Therefore, the flip-flop 622 is set and outputs a high level signal from its output terminal Q, and the signal is
It is supplied to the armature coil 321 of the vacuum pump 30 via the buffer 628. Therefore, the motor 320 of the vacuum pump 30 is driven to rotate, and the vacuum pump 30 supplies negative pressure to the port 111. Step as above
When the timer counter Ct is set to a predetermined value in step 246, during subsequent VP processing, a negative determination is made in step 241 and step 249 is processed, so that the set value of the timer counter Ct is set to "1" in step 249. The operation of the vacuum pump 30 is continued until the value becomes "0".

Also, when the deviation ΔV is larger than the predetermined value
In order to proceed to steps 246 and 247, the vacuum pump 30 is operated for T seconds as described above.

After that, if the deviation ΔV becomes "0" or negative, or if the deviation ΔV is between "0" and the predetermined value X, and the vacuum switch 40 is not turned on, the process advances to step 248, where: A signal is input from the output port 617 to the reset input terminal R of the flip-flop 622, and the flip-flop 622 is reset.
22 is reset, the vacuum pump 3
0 is deactivated, but if the deviation ΔV is still larger than the predetermined value X or is between "0" and The operation of the Yum pump 30 for T seconds is repeated.

On the other hand, while constant speed driving control is being performed as described above,
When the resume switch 532 is turned on,
The constant speed driving control routine includes steps 201, 202,
Proceed as 204, 207, 212, 213, 214, but step 214
Now, this is determined to be positive, and steps 215 to 217
will proceed to. In step 215, a known accelerator process is executed, and in step 216, the timer counter Ct is cleared, and further, in step 216, the timer counter Ct is cleared.
At 217, a signal to turn on the vacuum pump 30 is output. Therefore, the resume switch 53
2 is turned on, the accelerator process is performed and the vacuum pump 30 continues to be operated. In addition, the accelerator processing is
The signal Vc output from the output port 616 is
This is the process of setting the maximum value and resetting the set vehicle speed Vset. As a result of setting Vc to the maximum value, the duty ratio of the control coil 121 whose duty ratio is controlled as described above becomes 90%. Therefore, in the actuator 10, the control valve 122 is held in the position where the port 111 is opened and the port 112 is closed for a longer period of time. The negative pressure generated by the throttle valve 22 is rapidly introduced, and the opening degree of the throttle valve 22 is increased. In other words, the vehicle will be accelerated.

After achieving the desired acceleration, the resume switch 5
When the ON operation of step 32 is canceled, a negative judgment is made again in step 214, and the VP processing in steps 240 and 250 is performed.
Since the during-setting process is now executed, constant speed driving control is performed at the vehicle speed after acceleration.

This time, in order to reduce the vehicle speed while driving at a constant speed,
When the set switch 531 is turned on, the constant speed driving control routine starts at steps 201, 202, 204, and 207.
As step 207 is determined to be positive,
Processing of steps 208 to 211 is executed, and step
In step 208, the timer counter Ct is cleared, and in step 209, a signal to turn off the vacuum pump 30 is output. Also, in step 210,
A known coast process is performed, and in step 211,
Set switch flag SSF is set. Therefore, while the set switch 531 is turned on, the vacuum pump 30 is stopped and coast processing is performed. Note that coast processing refers to the signal output from the output port 616.
This is a process in which Vc is set to 0, a signal is output from the output port 617 to the reset input terminal R of the flip-flop 629, and the set vehicle speed Vset is reset. Vc is set to “0” and output port 6
As a result of the aforementioned signals being output from 17, flip-flop 624 and flip-flop 6
A high-level signal is no longer output from the output terminal Q of 29, and both the control coil 121 and the release coil 131 are brought into a non-energized state. Therefore, in the actuator 10, the control valve 122 and the release valve 132 are held in the positions shown in FIG.
Atmospheric pressure is rapidly introduced into the pressure chamber 103 from ports 112 and 113, and the throttle valve 2
2 is closed. In other words, engine braking is applied to the vehicle, and the vehicle speed V is gradually reduced.

After achieving the desired deceleration, set switch 531
When the ON operation is canceled, a negative determination is made in step 207, an affirmative determination is made in step 212, and the setting process of step 270 is executed again. In the setting process, as shown in FIG. 8, in step 231, the vehicle speed V at that time is set as the set vehicle speed Vset, so the decelerated vehicle speed V is set as the set vehicle speed Vset.
Constant speed driving control is performed as follows. In addition, as already explained, by executing the set time processing, the set switch flag SSF is reset and the set flag STF is set, so that after that, a negative decision is made in step 212, and an affirmative decision is made in step 213. Since the result of step 214 is negative, both steps 240 and 250 are executed to continue constant speed driving control.

While driving at a constant speed, when you step on the brake pedal or clutch pedal or operate the parking brake, one of the three cancel switches 54 is activated.
Since one of them is turned on, an affirmative decision is made in step 204, and the process proceeds to steps 205 and 206, where a known cancel process is performed.
Set flag STF and resume flag RSF
Processing to reset is performed. When the cancel processing in step 205 is performed, the above-mentioned steps are performed.
Output port 6 similar to coasting in 210
The signal Vc output from the flip-flop 629 is set to "0", and the signal is input from the output port 617 to the reset input terminal R of the flip-flop 629. Therefore,
Both the control coil 121 and the release coil 131 are de-energized, and the control valve 1 of the actuator 10
22 and the release valve 132 are maintained in the state shown in FIG.
Atmospheric pressure is introduced from 113, and the diaphragm 10
2 is deformed as shown by the bias force of a spring (not shown) to close the throttle valve 22. Of course, at this time, the throttle valve 22 can be opened arbitrarily by operating an accelerator pedal (not shown), but the actuator 10 does not open the throttle valve 22, and the constant speed running control is canceled. become.

Further, if the vehicle speed V exceeds the upper limit value (136 km/h) or the lower limit value (48 km/h) while driving at a constant speed or when turning on the main switch 52 in an attempt to travel at a constant speed, step 202 is negative. Therefore, in step 203, the set vehicle speed Vset is set to "0" and the
Processes 205 and 206 are executed, and constant speed driving control is canceled.

On the other hand, when the set vehicle speed Vset is not "0" but a certain vehicle speed V and the constant speed driving control is canceled, if the resume switch 532 is momentarily turned on, the constant speed driving control The routine proceeds through steps 201, 202, 204, 207, 212, 213, and 218, with an affirmative determination at step 218. and,
In step 219, the set vehicle speed Vset is "0".
If so, an affirmative judgment is made here and the processing of this routine ends. However, if the set vehicle speed Vset is not "0", the process proceeds to steps 220 to 224. First, in step 220, the resume switch 532 is turned on. Resume flag that remembers what has been operated
RSF is set, the timer counter Ct is cleared in step 221, and the vacuum pump 30 is operated in step 222. Also, step 223
Now, execute the known resume process and step
In 224, it is determined whether the resume processing is completed. In the resume processing in step 223, the already stored set vehicle speed Vset is not changed, but is set as the set vehicle speed, and while the set vehicle speed Vset and the current vehicle speed V are far apart, the process is performed so that the set vehicle speed Vset and the current vehicle speed V are rapidly brought into agreement. The signal Vc output from the output port 616 is set to the maximum value or the minimum value, and when the two approaches to a certain extent, Vc is set to an appropriate value to prevent overshoot or undershoot, and this process is completed. be.

Until the resume process is completed, a negative determination is made in step 224, and from then on, until the resume process is completed,
Steps 201, 202, 204, 207, 212, 213, 218,
Repeat steps 225, 223, and 224. In other words, since the resume switch 532 is already turned off at that time, a negative determination is made in step 218.
Further, since the resume flag RSF is set, an affirmative determination is made in step 225. and,
When the resume process is completed, an affirmative determination is made in step 224, and the process proceeds to steps 226 and 227, where the set flag STF is set so that normal constant speed driving control will be executed from now on, and will be activated at the start of the resume process. The operation of the vacuum pump 30 that has been in operation is stopped.

As described above, in the constant speed traveling device of the embodiment, during constant speed traveling, when the deviation ΔV of the vehicle speed from the set vehicle speed becomes larger than the predetermined value X, the vacuum pump 30 is operated unconditionally. If the negative pressure necessary to increase the vehicle speed is secured, the deviation ΔV is greater than "0", and at that time, the vacuum switch 40 is turned on and it is detected that the negative pressure in the surge tank 23 is small, The vacuum pump 30 is also operated to ensure the necessary negative pressure for the actuator 10. However, when the deviation ΔV is "0" or negative, there is no need to increase the vehicle speed and there is no need for negative pressure, so the vacuum pump 3
0 operation is stopped, and when the deviation ΔV is between "0" and the predetermined value X, it is detected that the vacuum switch 40 is off and the negative pressure in the surge tank 23 is large. When the vacuum pump 30 is in use, the negative pressure supplied by the surge tank 23 is sufficient, so the operation of the vacuum pump 30 is stopped. Furthermore, when the vehicle speed is increased by turning on the resume switch 532 while driving at a constant speed, or after the constant speed driving control is canceled, the resume switch 532 is momentarily turned on to turn on the constant speed driving control. When restarting, unconditionally use vacuum pump 30
to ensure the necessary negative pressure.

As a result, the necessity of negative pressure in the actuator 10 is determined by the deviation ΔV of the vehicle speed from the set vehicle speed and the magnitude of the negative pressure in the surge tank 23.
Accurately judge and use vacuum pump 3 only when necessary
0, and constant speed driving control can be performed normally without a vacuum tank, regardless of the vehicle's driving condition. As a result of not having to provide a vacuum tank, the weight and space occupied by the constant speed traveling device can be kept small, and
This eliminates the need for a large vacuum pump to maintain a large negative pressure in the vacuum tank or a special vacuum switch with large hysteresis to prevent hunting. Furthermore, the operation of the vacuum pump is kept to the minimum necessary as mentioned above.
As in the case of systems with a vacuum tank, the vacuum pump is actuated at any time, regardless of the need for the actuator, in order to maintain the negative pressure in the vacuum tank at a constant value. The life of the pump can be extended.

In the flowchart of FIG. 9, the processes in steps 243 and 244 correspond to the determining means of the first invention and the fourth invention, and the process of step 247 corresponds to the driving means of the first to fourth inventions. do. Also,
The processing in step 243 corresponds to the first determination means of the second and third inventions, the processing in steps 244 and 245 corresponds to the second determination means of the second and third inventions, and the processing in steps 241 and 246 corresponds to the second determination means of the second and third inventions. , 249 processing is the third
This corresponds to the timer means of the invention. Furthermore, Figure 7B
In the flowchart, the processes of steps 213 and 214 correspond to the acceleration operation detection means of the fourth invention,
The process in step 217 corresponds to the driving means of the fourth invention.

[Brief explanation of drawings]

1 to 4 are claims correspondence diagrams, FIG. 5 is a schematic configuration diagram of an embodiment of the present invention, and FIG.
A block diagram showing the configuration of the control circuit in FIG. 5, and FIGS. 7 to 10 are flowcharts showing the program contents of the microcomputer in FIG. 10...Pneumatic actuator, 101...
Casing, 102...Diaphragm, 103...
...Pressure chamber, 21...Engine, 22...Throttle valve, 23...Surge tank (intake pipe), 3
0... Vacuum pump, 40... Vacuum switch, 51... Vehicle speed sensor, 52... Main switch, 53... Control switch, 54...
...cancel switch, 60...control circuit.

Claims (1)

[Scope of Claims] 1. A pneumatic actuator that operates a diaphragm using air pressure in a pressure chamber and adjusts the opening degree of a throttle valve by the operation of the diaphragm, and is capable of controlling an arbitrarily set vehicle speed and the current speed. It is a constant speed traveling device that compares the vehicle speed and controls the negative pressure and atmospheric pressure introduced into the pressure chamber so that the two match. A vacuum pump that supplies negative pressure to a communication path that communicates the intake pipe downstream of the throttle valve with the pressure chamber of the pneumatic actuator, and the vehicle speed is lower than the set vehicle speed, and the difference between the vehicle speed and the set vehicle speed is greater than a predetermined value. A constant speed traveling device comprising: determining means for determining whether or not the vehicle is in a low speed state; and driving means for driving a vacuum pump when the determining means determines that the vehicle is in the low speed state. 2. It is equipped with a pneumatic actuator that operates a diaphragm using the air pressure in the pressure chamber and adjusts the opening degree of the throttle valve by the operation of the diaphragm, and compares the arbitrarily set set vehicle speed with the current vehicle speed, It is a constant speed traveling device that controls the negative pressure and atmospheric pressure introduced into the pressure chamber so that the two coincide, and it can be switched between a driving state and a stopped state. A vacuum pump that supplies negative pressure to the communication passage that communicates the intake pipe and the pressure chamber of the pneumatic actuator detects whether the vehicle speed is lower than the set vehicle speed and the difference between the vehicle speed and the set vehicle speed is greater than a predetermined value. a first determining means for determining; and a first determination means provided to detect intake pipe negative pressure downstream of a throttle valve of the engine, and detecting that the intake pipe negative pressure has become a low negative pressure state on the atmospheric pressure side than a predetermined negative pressure. a vacuum switch that detects a low negative pressure state; a second determination means that determines whether or not the vacuum switch detects a low negative pressure state; A constant speed traveling device comprising: a drive means for driving a vacuum pump when the means determines that the state is in a low negative pressure state. 3 Equipped with a pneumatic actuator that operates a diaphragm using the air pressure in the pressure chamber and adjusts the opening degree of the throttle valve through the operation of the diaphragm, and compares the arbitrarily set set vehicle speed with the current vehicle speed, It is a constant speed traveling device that controls the negative pressure and atmospheric pressure introduced into the pressure chamber so that the two coincide, and it can be switched between a driving state and a stopped state. A vacuum pump that supplies negative pressure to the communication passage that communicates the intake pipe and the pressure chamber of the pneumatic actuator detects whether the vehicle speed is lower than the set vehicle speed and the difference between the vehicle speed and the set vehicle speed is greater than a predetermined value. a first determining means for determining; and a first determination means provided to detect intake pipe negative pressure downstream of a throttle valve of the engine, and detecting that the intake pipe negative pressure has become a low negative pressure state on the atmospheric pressure side than a predetermined negative pressure. a vacuum switch that detects a low negative pressure state; a second determination means that determines whether or not the vacuum switch detects a low negative pressure state; A driving means for driving the vacuum pump when the means determines that the vacuum pump is in a low negative pressure state, and a timer means for continuing driving the vacuum pump by the driving means for a certain period of time. Constant speed running device. 4 Equipped with a pneumatic actuator that operates a diaphragm using the air pressure in the pressure chamber and adjusts the opening degree of the throttle valve through the operation of the diaphragm, and compares the arbitrarily set vehicle speed with the current vehicle speed, It is a constant speed traveling device that controls the negative pressure and atmospheric pressure introduced into the pressure chamber so that both coincide with each other, and so that the vehicle speed increases along with the set vehicle speed in response to acceleration operations. a vacuum pump whose state is switchable and which supplies negative pressure to a communication path that communicates an intake pipe downstream of a throttle valve of an engine with a pressure chamber of a pneumatic actuator in a driving state; and a vehicle speed is lower than a set vehicle speed, and A determination means for determining whether or not the vehicle speed is in a low speed state where the difference between the vehicle speed and the set vehicle speed is larger than a predetermined value; an acceleration operation detection means for detecting that an acceleration operation is being performed to increase the vehicle speed along with the set vehicle speed; If it is determined that the speed is low,
Alternatively, a constant speed traveling device comprising: drive means for driving the vacuum pump when an acceleration operation is detected by the acceleration operation detection means.