JPS6130430A - Constant-speed travelling device - Google Patents

Abstract

PURPOSE:To prevent a car speed from being rapidly increased due to an actuator by controlling an amount of introduction of negative pressure into a pressure chamber of the actuator for controlling the degree of opening of a throttle valve by suppressing said amount, when the acceleration of a vehicle gets higher than a prescribed value. CONSTITUTION:The captioned device introduces, besides intake air negative pressure, negative pressure from a vacuum pump 30 driven by an operating means A such as a motor into a pressure chamber 103 of an actuator 10, while it introduces atmospheric pressure into the same chamber 103 for driving the actuator 10 and for thereby controlling the degree of opening of a throttle valve 22. Thereupon, the introduction of the negative pressure and the atmospheric pressure into the pressure chamber 103 is controlled via solenoid control valves 121, 131 controlled in its duty ratio by duty control means B based on an output from car speed difference detector means C. A maximum value of the degree of the control means B, when judged to be in a vehicle rapid acceleration state by vehicle acceleration judging means D, is changed to be reduced by a prescribed value by making use of altering means E.

Description

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

[Prior art]

In a constant speed traveling system W using a pneumatic actuator (for example, disclosed in Japanese Patent Laid-Open No. 57-792217), a diaphragm is operated by the air pressure in the pressure chamber of the actuator, and the throttle valve is opened by the operation of the diaphragm. Adjust the degree. 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 amount of negative pressure introduced into the pressure chamber increases and the pressure (absolute pressure) in the pressure chamber decreases, the diaphragm is deformed greatly to increase the opening of the throttle valve, and vice versa. The pressure in the pressure chamber increases and the opening degree of the throttle valve is reduced.

Conventionally, in a constant speed traveling device 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, so the negative pressure in the intake pipe is large (
(low in terms of absolute pressure), the necessary and sufficient negative pressure is supplied to the pressure chamber of the actuator, and control to maintain the vehicle speed at the set vehicle speed can be performed normally. However, when the vehicle is running at a constant speed and approaches an uphill road, the load on the engine increases (as a result, the negative pressure in the intake pipe decreases, making it impossible to supply the necessary negative pressure 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, so the pressure in the pressure chamber must be lowered. Therefore, the opening of the throttle valve cannot be increased.As a result,
It becomes impossible to maintain the set vehicle speed on the road.

In addition, in recent years, some vehicles are equipped with turbochargers in their engines, and in such cases, when the turbocharger is activated, the pressure in the intake pipe becomes high (or negative) even when the vehicle is not driving uphill. As a result, sufficient negative pressure cannot be supplied to the pressure chamber of the actuator.
It may not be possible to maintain the set vehicle speed normally.

To solve this problem, a vacuum pump is installed in addition to the engine's intake pipe negative pressure as a source of negative pressure to the actuator's pressure chamber. The present applicant has considered a system that operates a vacuum pump to ensure the necessary negative pressure (not yet known).

According to this system, the negative pressure necessary for the actuator can be ensured and the vehicle speed maintained at the set vehicle speed can be normally controlled regardless of the driving state of the vehicle or the operation of the turbocharger.

However, since the vacuum pump only supplies negative pressure to the pressure chamber of the actuator, depending on the amount of negative pressure required in the actuator and the vacuum pump's ability to supply negative pressure, the pressure from the vacuum pump to the actuator may vary. The introduction speed of the negative pressure introduced into the chamber may be too rapid, and the opening degree of the throttle valve by the actuator may be too large. If the opening degree of the throttle valve is large, there is a problem in that the vehicle accelerates rapidly and does not run smoothly.

[Purpose of the invention]

In view of such conventional problems, an object of the present invention is to monitor the acceleration of the vehicle, and when the acceleration becomes larger than a predetermined acceleration, suppress the amount of negative pressure introduced into the pressure chamber of the actuator. By doing so, the purpose is to prevent the actuator from increasing the vehicle speed too rapidly.

[Structure of the invention]

The structure of the present invention for achieving this object will be explained with reference to FIG.

In a constant speed traveling device equipped with a vacuum pump as described above, the vehicle speed difference detection means determines the difference between the set vehicle speed and the current vehicle speed, and the duty ratio control means introduces negative pressure and atmospheric pressure into the pressure chamber of the actuator. is performed by duty ratio control. The duty ratio is adjusted within a range that does not exceed a predetermined maximum value so that the vehicle speed difference determined by the vehicle speed difference detection means is zero.On the other hand, the vacuum pump operating means operates the vacuum pump to The determination means detects the acceleration of the vehicle and determines whether the acceleration is in a sudden acceleration state higher than a predetermined acceleration.The maximum duty ratio changing means then changes the maximum value of the duty ratio in the duty ratio control means. When the vehicle acceleration determining means determines that the vehicle acceleration is in a sudden acceleration state, the vehicle acceleration during operation of the vacuum pump is decreased by a predetermined amount, and when it is determined that the vehicle acceleration is not in a sudden acceleration state, it is increased by a predetermined amount.

As a result, when the vacuum pump is operating, the acceleration of the vehicle is monitored, and if the acceleration is in a sudden acceleration state higher than a predetermined acceleration, the maximum value of the duty ratio in the duty ratio control means is reduced, so that the vehicle is not in a sudden acceleration state. In this case, the maximum value of the duty ratio is increased. Therefore, the maximum value of the duty ratio in the duty ratio control means, that is, the maximum value of the amount of negative pressure introduced into the pressure chamber of the actuator, is controlled so that the vehicle acceleration is equal to or less than the predetermined acceleration.

〔Effect of the invention〕

According to the present invention, since the maximum value of the amount of negative pressure introduced into the pressure chamber of the actuator is controlled and the vehicle acceleration is suppressed to a predetermined acceleration or less, there is no sudden increase in vehicle speed, and the constant speed traveling device can smoothly drive the vehicle. It can be done.

〔Example〕

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

FIG. 2 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 traveling device. The control circuits are shown respectively.

The pneumatic actuator 10 is a known one, and a pressure chamber 103 is formed by a casing 101 and a diaphragm 102 provided within the casing 101. The diaphragm 102 is connected to the throttle valve 22 by a link 24, and the pressure chamber 103 includes a boat 1.
Negative pressure and atmospheric pressure are introduced via 11-113.

Negative pressure and atmospheric pressure are introduced into the pressure chamber 103, and the pressure chamber 1
When the pressure in the pressure chamber 103 (absolute pressure, the same applies hereinafter) is adjusted to a predetermined pressure, the opening degree of the throttle valve 22 is set to the predetermined opening degree, and the pressure in the pressure chamber 103 is lower than the predetermined pressure (when the opening degree of the throttle valve 22 becomes lower than the predetermined pressure). degree becomes larger than the predetermined opening degree,
Conversely, as the pressure in the pressure chamber 103 increases, the opening degree of the throttle valve 22 decreases. When the pressure in the pressure chamber 103 reaches atmospheric pressure, the throttle valve 22 is fully closed as shown. 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 the boat 111 as will be described later, and atmospheric pressure is introduced from the boats 112 and 113. Each of these boats 111 to 113 is opened and closed by a control valve 122 and a release valve 132, and the control valve 122 swings around a fulcrum 123 to open and close the boats.
．． 112 is alternately opened and closed, and the release valve 132 is connected to the fulcrum 133.
The boat 113 is selectively opened and closed by swinging around the center.

The control valve 122 is energized when the control coil 121 is energized to open the boat 111 and open the boat 111.
The release valve 132 is energized to close the boat 113 when the release coil 131 is energized. These control coil 121 and release coil 13
1 is energized and controlled by an output signal from the control circuit 60.

Boat iii is connected to surge tank 23, which is part of the intake pipe, via communication passage 76.75. The surge tank 23 forms an intake path for the engine 21 together with the turbocharger 25, throttle body 27, intake manifold 26, etc.
5 is not operating, the inside of the surge tank 23 is at negative pressure due to the intake action of the engine 21. This negative pressure is led to the boat 11.1 via the communication passage 75.76. 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 the boat 111. Therefore, a vacuum pump 30 is provided in the middle of the communication path 75, 76.

The vacuum pump 30 is a known one, and includes a casing 301 and a diaphragm 302 provided therein to form a pump chamber 303, communicate with this pump chamber 303 to form chambers 304 and 305, and A chamber 306 is formed in communication with the chamber 305 . A check valve 31 is provided between the pump chamber 303 and the chamber 304.
Similarly, a check valve 312 is provided between the pump chamber 303 and the chamber 305, and a check valve 313 is provided between the chamber 305 and the chamber 306. 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 open to the atmosphere, the chamber 305 is communicated with the communication passage 76, and the chamber 306 is
It is communicated with a communication path 75.

The vacuum pump 30 also includes a motor 320, which rotates a rotor (not shown) when its armature coil 321 is energized, and its rotational output is output from an output shaft 331 integrated with the rotor. taken out. An eccentric cam 333 is coupled to the tip of the output shaft 331 of the motor 320, and when the output shaft 331 rotates as shown by the arrow, the rod 332 sliding on the eccentric cam 333 moves as shown by the arrow. make it vibrate. Mouth 7 Do 33
The side opposite to the eccentric cam 333 side of No. 2 is the diaphragm 30
When the rod 332 is vibrated, the diaphragm 302 is also vibrated and the pump chamber 303
Repeat the operation of shrinking and expanding the volume. 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 reduced or expanded, when the volume is reduced, the air inside the pump chamber 303 is removed by the check valve 311.
When expanded, the chamber 305 is discharged into the pump chamber 303 through the check valve 312.
Inhale air.

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 transferred to the chamber 306 and the communication passage 7.
5, the negative pressure supplied from the surge tank 23 to the chamber 306 is also supplied to the chamber 305.

Further, a vacuum switch 40 is connected to the communication path 75. The vacuum switch 40 is a known one, and a casing 41 and a diaphragm 42 provided therein form two chambers 45 and 46, one chamber 45 communicating with the communication path 75 and the other chamber 45 communicating with the communication path 75. Chamber 46 is open to the atmosphere. A contact 43 is fixed to the diaphragm 42 on the chamber 46 side, and a contact 44 is fixed to the casing 41 on the chamber 46 side opposite to this contact 43. Further, a spring 47 is inserted between the diaphragm 42 and the inner wall of the casing 41, and constantly biases the diaphragm 42 so as to reduce the volume of the chamber 46.

Therefore, if the negative pressure introduced into the chamber 45 from the communication path 75 is lower than the predetermined negative pressure (higher as an absolute pressure, the same applies hereinafter),
Both contacts 43 and 44 are connected by the spring 47's pie scan.
are in contact with each other, and when the negative pressure in the chamber 45 is higher than the predetermined negative pressure (lower as an absolute pressure, the same applies hereinafter), the diaphragm 42
Both contacts 43, 44 are spaced apart so as to reduce the volume of the contact points 43,44. Contact 43 is grounded, and contact 44 is connected to one input terminal of control circuit 60.

The control circuit 60 is connected to an on-vehicle battery 71 via an ignition switch 72, and each signal from the vehicle speed sensor 51, main switch 52, control switch 53, and cancel switch 54 is input to the control circuit 60 as input signals. has been done.

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 loaf magnet 5
The reed switch 511 placed under the influence of the magnetic field No. 12 is turned on and off at a frequency proportional to the vehicle speed.

The main switch 52 is a switch that is arbitrarily turned on and off by the occupant, and when turned on, inputs a voltage signal supplied from the batch IJ 71 via the ignition switch 72 to the control circuit 60. The control switch 53 includes one movable contact 533 and two fixed contacts 534 and 535. It constitutes a switch 532. The center switch 531 and the resume switch 532 are momentary type switches that are turned on when the passenger arbitrarily operates them, and are always turned off when the operating force is released. The movable contact 533 is grounded, and both switches 531.
532 inputs a ground signal to the control circuit 60 when both are turned on.

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 that is turned on when the parking brake is operated. One is a brake switch 542, and one is a clutch switch 543 that is turned on when the clutch pedal is depressed. In the case of 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.

The stop lamp switch 541 is connected between the stop lamp 73 and the batch IJ 71 as is known.
A voltage signal between the two is input to the control circuit 60. Further, 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, and the voltage signal between the parking brake lamp 74 and the parking brake switch 542 is connected to the battery 71. It is input to the control circuit 60. Further, the clutch switch 543 inputs a ground signal to the 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 includes a microprocessor (MPLJ) 611, a read-only memory (ROM) 612, and a random access memory (R
AM) 613, input portlo 15 and output portlo 1
6.617, which are connected to each other by a common bus 618. Further, the microcomputer has a clock generator 614, and the clock generator 61
4 is a clock signal for MPU611 operation.
1, and also supplies predetermined clock signals to each section within the control circuit 60.

In addition, the control circuit 60 includes a set-reset type flip-flop 624 for forming an output signal to the control coil 121, a down counter 623, and an AND circuit 625.
, a center-reset type flip-flop 629 for forming an output signal to the release coil 131, a set-reset type flip-flop 622 for forming an output signal to the armature coil 321 of the vacuum pump 30, and a set-reset type flip-flop 622 for forming an output signal to the armature coil 321 of the vacuum pump 30. It has buffers 626 to 628 and a constant voltage circuit 621 for supplying a constant voltage to each part in the control circuit 60.

The input port 15 includes a vehicle speed sensor 51, a main switch 52, a set switch 531, and a resume switch 5.
32, a signal is input from the cancel switch 54 and the vacuum switch 40, and the vehicle speed sensor 51
Other signals are transmitted from the MPU 611 in response to requests from the MPU 611.
611. On the other hand, when the pulse signal from the vehicle speed sensor 51 is input to the input port 15,
An interrupt request is made to the MPU 611 to start a known vehicle speed calculation processing routine among the programs stored in the ROM 612 in advance. 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 then stored at a predetermined address in the RAM 613.

The control coil 1 is connected to the output port 16 from the MPU 611.
21 is outputted, and the output data is outputted from the output port 16 to the down counter 623. The down counter 623 output port 1
The data output from the clock generator 614 is used as a precent value and is counted down by a clock signal from a 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. A clock signal from the clock generator 614 is input to the cent input terminal S of the flip-flop 624 . Here, the clock signal input to the set input terminal S of the flip-flop 624 is, for example, a 10 Hz signal,
The clock signal input to the down counter 623 is I
It is a KHz signal. Further, the maximum value of data outputted from the output port 16 to the down counter 623 as the energization time of the control coil 121 is set to "100" (actually, "90" is the upper limit as described later).

The flip-flop 624 outputs a high-level signal from the output terminal Q after the signal is input to the set input terminal S until the signal is input to the reset input terminal R. The output signal of the flip-flop 624 is sent to the AND circuit 6
25 and a buffer 626 to the control coil 121.

Therefore, as described above, when the clock signal to the cent input terminal S of the flip-flop 624 is 10 Hz and the clock signal to the down counter 623 is lKH2, the control coil 121 controls the duty ratio at a period of 100"17 seconds. If the data output from the output port 16 is 50, the duty ratio is 50%, and if the data is 70, the duty ratio is 70%.

The output port 17 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. The output terminal Q of the flip-flop 629 outputs a signal that is at a high level from when the signal is input to the node input terminal S until the signal is input to the node input terminal R. This signal is input to the AND circuit 625 and is also supplied to the cancellation coil 131 via the buffer 627. Further, the ON signal of the vacuum pump 30 is input to the set input terminal S of the flip-flop 622, and the OFF signal is input to the reset input terminal R of the flip-flop processor 22.

The flip-flop 622 outputs a high-level signal from the output terminal Q after a signal is input to the set input terminal S until a signal is input to the reset input terminal R. Therefore, the output terminal Q is at high level. While outputting the signal,
The armature coil 321 of the vacuum pump 30 is energized via the buffer 628, and the vacuum pump 30 is activated.

4 to 8 show a part of the program stored in the ROM 612, and the operation of the above embodiment will be explained below according to these flowcharts.

4A to 4C 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, step 20
2, the current vehicle speed V stored in a predetermined location of the RAM 613 is read, and the upper limit value of the vehicle speed V stored in advance in the ROM 612, for example, 136 Km/h is read.
and a lower limit value, for example 48 km/h, are read into the MPU 611, and it is determined whether the current vehicle speed ■ is between the upper limit value and the lower limit value. If the main switch 52 is not on,
Alternatively, 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;
Next, in step 205, cancellation processing, which will be described later, is performed. In other words, if the vehicle speed ■ 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 (2) is between the above upper limit and lower limit, it is determined in step 204 whether any of the cancel switches 54 are on. If none of the cancel switches 54 are turned on, in step 207, the current set switch 531
is turned on. If the set switch 531 is currently turned on, in steps 208 and 209, a timer counter Ct, which will be described later, is activated.
Clear ST2 and vacuum pump drive flag V
A signal for resetting the DF and turning off the vacuum pump 30 is output from the output port 17. Further, in steps 210 and 211, coasting processing to be described later is performed, and a set switch flag SSF is set to store in a set state that the set switch 531 has been turned on, and the processing of this routine is ended.

In step 207, currently the cent switch 531
If the set switch 531 has not been turned on, it is determined in step 212 whether the set switch flag SSF is set, thereby determining whether the set switch 531 was turned on in the previous processing cycle. If the set switch flag SSF is set, cent time processing, vp processing, and set processing are executed in steps 230.700.250.

The setting process is as shown in FIG. 5. First, in step 231, R is set as vehicle speed data.
The vehicle speed V stored in AM613 is set as the set vehicle speed Vse.
It is stored at a predetermined location in the RAM 613 as t. Next, in step 232, a set flag STF is set to remember that the constant speed driving control process has started, and
The set switch flag SSF and the resume flag R3F, which will be described later, are reset. Then, in step 233, Vc is determined as the output signal from the output port 16 using XVset. Here, K is a constant. Furthermore, in step 234, an ON signal for the release coil 131 is outputted from the output port 17, the flip-flop 629 is set, and a high level signal is outputted from its output terminal Q. Therefore, the release coil 131 is energized and the release valve 132 closes the port 113.

The VP process is as shown in FIG.
0'', an affirmative determination is made in step 731, and in step 733, the vehicle speed difference ΔV, which is the difference between the set vehicle speed Vset and the current vehicle speed V, is determined from Vset-'V. In the next step 734, the vehicle speed difference Δ■ is 3 K m.
/h, and in step 711, it is determined whether the vacuum switch 40 is on. Now, the set vehicle speed Vset and the vehicle speed V match, the vehicle speed difference Δ■ is "0", and the surge tank 2
If the negative pressure at step 3 is also greater than the predetermined negative pressure and the vacuum switch 40 is turned off, a negative determination is made in both steps 734 and 711, and the process proceeds to step 738, where:
An off signal for the vacuum pump 30 is output from the output port 17. Therefore, the reset circuit of flip-flop 622
A signal is input to the throat input terminal R, the free knob flop 622 is reset, no signal is output from its output terminal Q, and the armature coil 321 is not energized. Therefore, the vacuum pump 30 is not operated. Next, in step 715, the vacuum pump flag VPF, which will be described later, is
and the vacuum pump drive flag ■DF, as well as timer counter T and T2, which will be described later.
is cleared, and in step 739, processing is performed to set the maximum value VcMAX of the output signal Vc from the output port 16 to "90". Note that the processing contents of other steps in FIG. 6 will be described later.

The processing during setting is as shown in FIG. 7, and in step 251, Vc is determined as the output signal from the output port 16 by 2XΔ■. Here, K2 is a constant, but if the vehicle speed difference ΔV is "0", Vc is not changed. Then, in step 252, it is determined whether the signal Vc obtained in step 251 is larger than its maximum value VCMAX. V
If c is greater than the maximum value VcMAX, an affirmative determination is made in step 252 and the process proceeds to step 253, where Vc is made equal to the maximum value VcMAX. However, if Vc is less than or equal to the maximum value VcMAX, step 252 is If a negative determination is made, the process proceeds to step 254 without changing Vc. Then, in step 254, V
Output c. When Vc is output from the output port 16, this value is set as a preset value of the down counter 623, and is counted down using, for example, an IKHz clock signal. When the down count is completed, a signal is input to the reset input terminal R of the flip-flop 624, and the flip-flop 624 is reset. Since the flip-flop 624 inputs a clock signal to the set input terminal S in synchronization with the startup of the routine, the clock signal from the output terminal Q is proportional to the signal Vc output from the output port 16. A signal with the specified time width (duty ratio) is output. As mentioned above, the flip-flop 629 has already generated a high-level signal, so when the signal is output from the flip-flop 624, the signal is supplied to the control coil 121 via the AND circuit 625 and the buffer 626. and the control coil 121 is energized for a time proportional to the signal Vc, during which time the control valve 1
22 opens the boat 111 and closes the port 112.

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, the main switch 52, the set switch 531,
Unless either the resume switch 532 or the cancel switch 54 is operated, the main switch 52 is turned on, the set switch 531, the cancel switch 54,
Since all the resume switches 532 are off, the set flag STF is set to cent, and the cent switch flag SSF is reset, steps 20'l and 20' are executed every time the constant speed running control routine is executed every 100 milliseconds.
2.204.207.212.213.214, the VP process in step 700 and the in-set process in step 250 are repeatedly executed.

Therefore, in the vp process, as shown in FIG.
A process is performed to output an on signal or an off signal for the vacuum pump 30 from the output port 17 according to the value of VcMAX and the on/off state of the vacuum switch 40. , Vc+, the output signal Vc from the output port 16 is corrected according to the vehicle speed difference ΔV using the calculation formula 2×Δ■.

To explain in detail the vP processing at this time, step 73
3, find the vehicle speed difference ΔV, and find that the vehicle speed difference Δ■ is 3 Km/h
If the vacuum switch 40 is off in the following, both steps 734 and 711 are negative, so in step 738 an off signal for the vacuum pump 30 is output, and the vacuum pump 30 is still not operated.

Further, when the vehicle speed difference ΔV is greater than 3 Km/h, an affirmative determination is made in step 734, so step 735.4
Go to 00 and now vacuum pump 30 for 14 seconds
will be activated. That is, in step 735, the value r140 corresponding to 14 seconds is set to the timer counter (,1).
J (Since this routine is activated every 100 milliseconds, the value r140J of the timer counter Ct is 100 milliseconds.
If it is decremented every S seconds, it will become "0" in 14 seconds)
is set, and in step 400, the subroutine shown in FIG. 8 is executed and the operation of the vacuum pump 30 is started. The details will be described later, but when the subroutine is executed in step 400, the output port 17
An on-signal from the vacuum pump 30 is input to the set input terminal S of the flip-flop 622. For this reason,
Flip-flop 622 is set and outputs a high level signal from its output terminal Q, and the signal is supplied to armature coil 321 of vacuum pump 30 via 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. As described above, when the timer counter Ct is set to a predetermined value in step 735, during subsequent VP processing, step 73
1 is negative and step 732 is processed, so in step 732, the set value of the timer counter Ct is decremented by "1" and the operation of the vacuum pump 30 is continued until it becomes "0". become.

After that, the vehicle speed difference ΔV becomes 3 Km/h or less,
If the vacuum switch 40 is also off, step 73
4.711 are both negative, and the process proceeds to step 738, where the output port 17 to the flip-flop 6
As a result of inputting a signal to the reset input terminal R of 22, the flip-flop 622 is reset, and the vacuum pump 30 is stopped, but even after that, the vehicle speed difference Δ■ is 3K.
If it is greater than m/h, the process proceeds to step 735.400, where the vacuum pump 30 is repeatedly activated for 14 seconds.

Further, when the negative pressure in the surge tank 23 becomes lower than the predetermined negative pressure and the vacuum switch 40 is turned on, an affirmative determination is made in step 711 and the process proceeds to step 736, where it is determined that the vacuum pump 30 is activated. It is determined whether or not the vacuum pump flag VPF, which is stored in a set state, is set. Initially, if the vacuum pump flag VPF has been reset, a negative determination is made in step 736, and the process proceeds to step 712, where it is determined whether the timer counter T is equal to or greater than "8". Initially, timer counter T1 is “0”.
”, a negative determination is made in step 712 and the process proceeds to step 713, where the timer counter T1 is incremented. Until the value of timer counter T1 reaches "8", step 712 is negative and step 71 is executed.
3, the timer counter T1 is incremented;
When step 713 is processed eight times, that is, 0°8 seconds have elapsed (because this routine is executed every 100 milliseconds), step 712 is answered in the affirmative, and timer counter T is set in step 714. It is cleared to "0" and the vehicle speed difference Δ■ is O at step 720.
It is determined whether or not it is greater than Km/h.

Therefore, when a predetermined period of time (here 0.8 seconds) has elapsed after the negative pressure in the surge tank 23 has become smaller than the predetermined negative pressure, the vehicle speed difference Δ■ becomes larger than the predetermined value, here 0K m/h. It is determined whether or not it is. At this time, if the vehicle speed difference Δ■ is larger than OK m/h, an affirmative decision is made in step 720, and steps 737, 735, and 40
0, sets the vacuum pump flag VPF, and operates the vacuum pump 30. However, if the vehicle speed difference ΔV is less than OK m/h, step 720
Since the determination is negative, the vacuum pump 30 is not operated in step 738.

In this way, the negative pressure in the surge tank 23 is lower than the predetermined negative pressure, the vacuum switch 40 is turned on, and the vehicle speed difference Δ
Even if V is larger than OK m/h, the vacuum pump 30 will not be activated until 0.8 seconds have passed after the vacuum switch 40 is turned on, so temporary speed increase is not allowed during constant speed driving control. (temporarily depress the accelerator pedal (not shown) and open the throttle valve 2.
2, and as a result, the negative pressure in the surge tank 23 may become smaller than the predetermined negative pressure, the vacuum pump 30 will not be activated unless this condition continues for 0.8 seconds or more, and the vacuum pump 30 will not be activated. It is possible to avoid unnecessary operation of the pump 30. However, when the negative pressure decreases not due to the depression of the accelerator pedal but due to an increase in the load on the engine 21 or the operation of the turbocharger 25, the vacuum pump 30 is activated after 0.8 seconds. . Then, once the vacuum pump 30 is activated, the vacuum pump flag VPF is set, so that after that, an affirmative determination is made in step 736, and 0.8
Step instantly without waiting for seconds to pass? At step 20, the vehicle speed difference ΔV is determined, and the vehicle speed difference ΔV is determined to be OK m.
/h or less, the vacuum pump 30 is immediately stopped in step 738. Then, in step 715, a vacuum pump flag VPF and a vacuum pump drive flag VDF, which will be described later, are reset, and a timer counter T and a timer counter T2, which will be described later, are cleared, and in step 739, the output from the output port 16 is reset. The maximum value VcMAX of the signal Vc is set to "90".

Next, the subroutine of step 400 will be explained with reference to FIG.

First, in step 421, it is determined whether the vacuum pump drive flag VDF, which stores in a cent state that the vacuum pump 30 has been activated, is set. At first, the vacuum pump drive flag VD
Since F has not been sent, a negative determination is made in step 421, and steps 422, 423, and 401 are performed.

In step 422, the ON signal of the vacuum pump 30 is output from the output port 17 to the flip-flop 622.
It is input to the throat input terminal S. Therefore, the flip-flop 622 is set and outputs a high-level signal from its output terminal Q, and the armature coil 321 is energized.

Therefore, the vacuum pump 30 is activated. Further, in step 423, since the vacuum pump 30 was activated by the processing in step 422, a vacuum pump drive flag VDF is set, and in step 401, the current vehicle speed V is stored as the vehicle speed Vo for acceleration calculation, which will be described later.

In this way, when the vacuum pump 30 is started and the vacuum pump drive flag VDF is set,
When the subsequent subroutine is executed, since an affirmative determination is made in step 421, steps 422, 423, and 401 are skipped, and step 424 is directly executed.

In step 424, the timer counter T2 is set to "0".
'', and if the timer counter T2 is rol, an affirmative determination is made in step 424, and the process proceeds to step 402, where it is determined whether the vehicle speed ■ is greater than Vo. . If ■ is less than or equal to ■ 0, step 402 is a negative judgment and the process proceeds to step 412, but ■
If is larger than Vo, an affirmative decision is made in step 402, and steps 403 and 404 are processed. Step 40
In 3, the difference between the current vehicle speed ■ and the stored vehicle speed Vo is
V-Vo, and the acceleration Va of the vehicle is calculated. Then, in step 404, the current vehicle speed ■ is re-stored as the vehicle speed Vo.

Next, in step 405, the acceleration Va calculated in step 403 is set to a value r 1 corresponding to a predetermined acceleration.
．． It is determined whether the value is larger than 6J.

If the acceleration Va is larger than r 1.6 J, an affirmative determination is made in step 405 and the process proceeds to step 411, where the maximum value VcMAX of the signal Vc output from the output port 17 is greater than the previous maximum value VcMAX. "3"
It is assumed that the value is less than that. Therefore, the maximum value Vc up to that point
If MAX is set to "90", the maximum value VcMAX is set to "87" in step 411.

However, the acceleration Va calculated in step 403
If the value r corresponding to the predetermined acceleration is less than 1.6 J, then
A negative determination is made in step 405. If step 405 is determined to be negative, the process proceeds to step 412, as in the case where step 402 is determined to be negative, and in step 412, it is determined whether "90" is set as the maximum value VcMAX at that time. . The maximum value VcMAX is r
91) In the case of J, an affirmative determination is made in step 412, and the maximum value VcMAX remains "90", but if the maximum value VcMAX is not "9゛0", step 4
12 is negative, and in step 413, the maximum value VcMAX is the maximum value VcMAX up to that point.
The value is set to be "3" more than that.

In this way, the signal Vc output from the output port 16
Since the maximum value VcMAX is set at "90" as the upper limit and is increased or decreased depending on the magnitude of the vehicle acceleration, the energization duty ratio of the control coil 31 of the actuator 30 is changed according to the vehicle acceleration. That is, in the setting process of step 250 in FIG.
Since c is close to the maximum value VcMAX in most cases, if the vehicle acceleration is larger than the predetermined acceleration, the maximum value Vc
When MAX is made small, the signal Vc is limited to a range in which the vehicle acceleration does not exceed a predetermined acceleration. As a result, the amount of negative pressure introduced into the pressure chamber 103 of the actuator 30 is limited, and the vehicle acceleration is no longer greater than a predetermined acceleration. Therefore, during constant speed driving control, there is no sudden increase in vehicle speed, and constant speed driving can be performed smoothly.

Next, in step 426, a value "10" corresponding to one second is set as the timer counter T2.

After "10" is set in the timer counter T2 in this manner, a negative determination is made in step 424 until one second has elapsed, and in step 425, the value of the timer counter T2 is decremented. When one second has passed and the value of the timer counter T2 becomes "0" and step 424 is affirmed, the processing from step 402 onwards is performed again, and the maximum value VcMAXO value is increased or decreased according to the acceleration Va. That will happen.

By the way, during constant speed driving control, the resume switch 5
32 is turned on, the constant speed running control routine starts at steps 201.202.204.207.2124.2.
13.214, but in step 214, No. 1 is answered in the affirmative, and the process proceeds to step 215.216.400. In step 215, a known accelerator process is executed, and in step 216, the timer counter C
t is cleared, and further, in step 400, the above-described subroutine is executed to operate the vacuum pump 30. Therefore, while the resume switch 532 is turned on, the accelerator process is performed and the vacuum pump 30 continues to be operated. Note that the accelerator process is a process of setting the signal Vc output from the output port 16 to the maximum value VcMAX and resetting the set vehicle speed Vset. Vc is the maximum value Vc
As a result of being set to MAX, the duty ratio of the control coil 121 whose duty ratio is controlled as described above is V
If c MAX is "90", it is 90%. Therefore, in the actuator 10, the control valve 122 is held in the position where the boat 111 is opened and the port 112 is closed for a longer period of time. A large amount of negative pressure is introduced, and the opening degree of the throttle valve 22 is increased (in other words, the vehicle is accelerated. However, as described above, the maximum value VcMAX is determined by the subroutine processing. It increases or decreases depending on the acceleration, so
During acceleration, the vehicle acceleration is not allowed to exceed a predetermined acceleration.

When the desired acceleration is achieved and the on-operation of the resume switch 532 is released, a negative determination is made in step 214 again, and the VP processing and in-setting processing in steps 700 and 250 are executed. Constant speed driving control will be performed at the later vehicle speed.

This time, when the set switch 531 is turned on in order to reduce the vehicle speed while driving at a constant speed, the constant speed driving control routine advances to steps 201, 202, 204, and 207, and since step 207 is determined to be affirmative, Step 20
Processes 8 to 211 are executed, and in step 208, timer counters Ct and T2 are cleared,
The vacuum pump flag VPF is reset, and in step 209, a signal is output to turn off the vacuum pump 30. Further, in step 210, a known coasting process is performed, and in step 211, a set switch flag SSF is set.

Therefore, while the cent switch 531 is turned on, the vacuum pump 30 is stopped and coast processing is performed. Incidentally, coast processing means that the signal Vc output from the output port 16 is set to "0", the signal is output from the output port 17 to the reset input terminal R of the flip-flop 629, and the set vehicle speed Vse is
This is a process of resetting t. As a result of Vc being set to "0" and the above-mentioned signal being output from the output port 17,
Flip-flop 624 and flip-flop 629
A high level signal is no longer output from the output terminal Q of the control coil 121 and the release coil 131 are both de-energized. Therefore, in the actuator 10, the control valve 122 and the release valve 132 are held at the positions shown in FIG. 2, atmospheric pressure is rapidly introduced into the pressure chamber 103 from the boats 112 and 113, and the throttle valve 22 is closed. . In other words, engine braking is applied to the vehicle, and the vehicle speed is gradually reduced.

When the desired deceleration is achieved and the ON operation of the cent switch 531 is released, a negative determination is made in step 207, an affirmative determination is made in step 212, and the setting process of step 230 is executed again.

In the setting process, as shown in FIG. 5, in step 231, the vehicle speed V at that time is set as the set vehicle speed Vset, so constant speed running control is performed using the decelerated vehicle speed 2 as the set vehicle speed Vset. In addition, as already explained, by executing the cent time processing, the set switch flag SSF is reset, and the set switch flag STF
is set, so that step 212 is subsequently determined to be negative, step 213 is determined to be affirmative, and step 214 is determined to be negative, so step 700.
The image processing of 250 is executed and constant speed driving control is continued.

While driving at a constant speed, when the brake pedal or clutch pedal is depressed or the parking brake is operated, one of the three cancel switches 54 is turned on, so that step 204 becomes affirmative, and step 205 Proceeding to step .206, a known cancellation process is performed, and a process of resetting the set flag STF and resume flag R3F is performed. When the cancel processing in step 205 is performed, the output port 1 is
The signal Vc output from the flip-flop 629 is set to "0", and the signal is input from the output port 17 to the reset input terminal R of the flip-flop 629.

Therefore, the control coil 121 and the release coil 131 are
Both are de-energized, and the control valve 122 of the actuator 10
and release valve 132 are held in the state shown in FIG. This will cause the throttle valve 22 to close. Of course, at this time, the throttle valve 22 can be opened arbitrarily by operating an accelerator pedal (not shown), but the opening is not performed by the actuator 10, and the constant speed running control is canceled.

Also, when the vehicle speed V is at the upper limit (136 Km/h) or lower limit (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,
If it exceeds, the determination in step 202 is negative, so in step 203 the set vehicle speed Vset is set to rOJ, the processes in steps 205 and 206 are executed, and constant speed driving control is canceled.

On the other hand, if the resume switch 532 is momentarily turned on when the set vehicle speed Vset is not rOJ but a certain vehicle speed V and the constant speed driving control is canceled,
The constant speed running control routine includes steps 201.202.2
04.207.212.213.218, and an affirmative determination is made in step 218. And step 219
In , if the set vehicle speed Vset is "0", an affirmative judgment is made and the processing of this routine ends; however, if the set vehicle speed Vset is not "0", steps 221 to
Proceeding to step 224, first, in step 221, the resume flag R3F, which stores that the resume switch 532 has been turned on, is reset, and in step 222,
Clear the timer counter Ct. Also, step 22
In step 3, a known resume process is executed, and in step 22
In step 4, it is determined whether the resume processing is completed.

In the resume processing at step 223, the already stored set vehicle speed Vset is not changed and is set as the set vehicle speed, and while the set vehicle speed Vset and the current vehicle speed V are far apart, the two are rapidly brought into agreement. Set the signal Vc output from the output port 16 to the maximum or minimum value, and when the two come close to a certain extent, set Vc to an appropriate value to prevent overshoot or undershoot, and complete this process. It is something.

Until the resume processing is completed, step 224
is determined to be negative, the above-mentioned subroutine is executed in step 400, the vacuum pump 30 is operated, and the maximum value VcMAX is increased or decreased in accordance with the vehicle acceleration Va to prevent the vehicle acceleration Va from exceeding a predetermined acceleration. Ru. Then, until the resume processing is completed, steps 201.202.204.207.2
12.213.218.225.223.224.40
Repeat the process for 0. In other words, already at that time.

Since the resume switch 532 is off,
A negative determination is made in step 218, and since the resume flag R3F is set, an affirmative determination is made in step 225. Then, when the resume process is completed,
If step 224 is answered in the affirmative, step 226.2
27, and in step 226 the set flag ST
After F is sent, normal constant speed running control is executed, the timer counter T2 is cleared, and the vacuum pump drive flag VDF is reset. Furthermore, in step 227, the operation of the vacuum pump 30 is stopped.

As described above, in the constant speed traveling device of the embodiment, during constant speed traveling, the vehicle speed difference Δ■ between the vehicle speed and the set vehicle speed is 3 K m.
/ h, the vacuum pump 30 is operated unconditionally to ensure the negative pressure necessary to increase the vehicle speed, and the vehicle speed difference ΔV is greater than OK m/h,
At that time, if the vacuum switch 40 is on and detects that the negative pressure in the surge tank 23 is small, the vacuum pump 30 is also activated and the actuator 10 is activated.
Ensure the necessary negative pressure. However, the vehicle speed difference ΔV is OK
/h or less or negative, there is no need to increase the vehicle speed and no need for negative pressure, so the vacuum pump 3
0 operation is stopped, and the vehicle speed difference Δ■ is OK m/h and 3
Km/h, when the vacuum switch 40 is off and detects that the negative pressure in the surge tank 23 is large, the negative pressure supplied by the surge tank 23 is sufficient, so the vacuum pump 30
stop operating. Furthermore, when the vehicle speed is increased by turning on the resume switch 532 while driving at a constant speed,
Alternatively, after the constant speed cruise control is canceled, when the resume switch 532 is momentarily turned on to restart the constant speed cruise control, the vacuum pump 30 is operated unconditionally to ensure a large amount of necessary negative pressure.

When the vacuum pump 30 is activated, the acceleration of the vehicle is monitored, and the maximum value of the duty ratio is adjusted so that the acceleration does not exceed a predetermined acceleration.

As a result, the negative pressure generated by the operation of the vacuum pump 30 is introduced into the actuator 30 to prevent a sudden increase in vehicle speed when constant speed driving control is performed, and smooth driving by the constant speed driving device is achieved. be able to.

In addition, in the flowcharts of FIGS. 4 to 8, the sixth
The process in step 733 in the figure corresponds to the vehicle speed difference detection means of the present invention, and the process in steps 215, 223 and 7 in FIG.
The processing of steps 251 to 254 in the figure corresponds to the duty ratio control means of the present invention, and the processing of step 422 of FIG. 8 corresponds to the vacuum pump operating means of the present invention, and the processing of steps 401 to 405 of FIG. The process corresponds to the vehicle acceleration determination means of the present invention, and is performed in steps 411 to 4 in FIG.
The process No. 13 corresponds to the maximum duty ratio changing means of the present invention.

Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and includes various embodiments within the scope of the claims. For example, the vehicle acceleration may be monitored all the time instead of every predetermined time. Further, the vehicle acceleration may be determined based on a signal from a mechanical acceleration sensor.

[Brief explanation of the drawing]

FIG. 1 is a complaint correspondence diagram, FIG. 2 is a schematic configuration diagram of an embodiment of the present invention, FIG. 3 is a block diagram showing the configuration of the control circuit in FIG. 2, and FIGS. 4 to 8 3 is a flowchart showing the program contents of the microcomputer in FIG. 3. FIG. 10-...Pneumatic actuator 10! −−・・
-Casing 102...Diaphragm 103...-Pressure chamber 21--Engine 22--Throft valve 23...Surge tank (intake pipe) 30...
-Vacuum pump 40--Vacuum switch 51--Vehicle speed sensor 52--Main switch 53--Control switch 54--Cancel switch 60--Control circuit

Claims (1)

[Claims] 1. Equipped with a pneumatic actuator that operates a diaphragm using air pressure in a pressure chamber and adjusts the opening of the throttle valve by the operation of the diaphragm, it compares the arbitrarily set vehicle speed with the current vehicle speed and makes sure that the two match. , controls the negative pressure and atmospheric pressure introduced into the pressure chamber,
The constant speed traveling device uses a vacuum pump as well as the engine's intake pipe negative pressure as a source of negative pressure, and includes a vehicle speed difference detection means for determining the difference between a set vehicle speed and a current vehicle speed, and a negative pressure to the pressure chamber of an actuator. duty ratio control means for introducing pressure and atmospheric pressure by duty ratio control, and adjusting the duty ratio so that the vehicle speed difference determined by the vehicle speed difference detection means disappears within a range not exceeding a predetermined maximum value; Vacuum pump operation means for operating a vacuum pump; Vehicle acceleration determination means for detecting acceleration of a vehicle and determining whether the acceleration is in a sudden acceleration state higher than a predetermined acceleration; and a duty ratio control means for controlling a duty ratio. The maximum value is decreased by a predetermined amount when the vehicle acceleration determining means determines that the vehicle acceleration during vacuum pump operation is in a sudden acceleration state, and is increased by a predetermined amount when it is determined that the vehicle acceleration is not in a sudden acceleration state. A constant speed traveling device comprising: duty ratio changing means;