JPH0260527B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a constant speed traveling device for an automobile,
More specifically, an improvement in a constant speed driving device for an automobile that controls the opening of a throttle valve using an actuator whose internal negative pressure is controlled by a vacuum pump and an air valve, and matches the speed of the vehicle with a target speed. It is related to.

[Prior Art] Fig. 5 is a block diagram showing an example of a conventional constant speed traveling device for automobiles, in which 51 is a reed switch for detecting vehicle speed, 52 is a permanent magnet, and 53 is a frequency-voltage converter (FV converter). 54 is an analog switch, 55 is a memory circuit, 56 is a differential amplifier, 58 is a duty ratio calculator, 59 and 60 are pulse generation circuits, 61 is a vacuum pump, 61a is a motor,
61b is a diaphragm, 61c, 61d are valves, 6
2 is an air valve, 62a is a solenoid, 62b
is a valve, 62c is an intake hole, 63 is an actuator,
63a is a diaphragm, 63b is a rod, 64 is a throttle valve, and 65 is a set switch.

The reed switch 51 is turned on as a permanent magnet rotates at a rotation speed proportional to the vehicle speed by a speedometer cable (not shown).
It turns off and outputs a pulse signal with a frequency proportional to the vehicle speed. This pulse signal is converted into a DC voltage at a level proportional to the vehicle speed V in the FV converter 53 and applied to one terminal of an analog switch 54 and a differential amplifier 56. The analog switch 54 remains on while the set switch 65 is on.
Adding the output voltage of the FV converter 53 to the memory circuit 55,
The memory circuit 55 stores and holds the output voltage of the FV converter 53 immediately before the analog switch 54 changes from on to off as a voltage proportional to the target vehicle speed Vm. The differential amplifier 56 calculates the difference between the output voltage of the FV converter 53 applied to one terminal and the voltage stored in the storage circuit 55 applied to the + terminal (speed difference ΔV between target vehicle speed Vm and vehicle speed V=Vm −V) is applied to the duty ratio calculators 57 and 58.

Duty ratio calculators 57 and 58 are differential amplifiers 5
The on-duty ratio Don of the pulse signal m and the off-duty ratio Doff of the pulse signal n are calculated based on the output voltage of No. 6, that is, the speed difference ΔV.
Figure 6 shows the speed difference ΔV and the on-duty ratio Don,
It is a diagram showing the relationship with the off-duty ratio Doff, and the duty ratio calculator 57 sets the on-duty ratio Don to 100% when ΔV<V1, and when ΔV>V2
In this case, the on-duty ratio Don is set to 0%, and V1
If ≦∆V≦V2, the on-duty ratio Don is calculated using the following formula.
(1).

Don=100(V2-ΔV)/(V2-V1)...(1) In addition, the duty ratio calculator 58 sets the off-duty ratio Doff to 0% when ΔV<V3, and ΔV>V4
In this case, the off-duty ratio Doff is set to 100%, and V3
When ≦ΔV≦V4, the off-duty ratio Doff shall be expressed by the following formula.

Doff=100(ΔV−V3)/(V4−V3) (2) Here, the on-duty ratio Don and the off-duty ratio Doff are defined by the following equations (3) and (4), respectively. However, in equations (3) and (4), T
is the period of the pulse signal, T1 is the time when the signal becomes "1" in one period of the pulse signal, and T2 is the time when the signal becomes "0" in one period of the pulse signal.

Don=T1/T=T1/(T1+T2)...(3) Doff=T2/T=T2/(T1+T2)...(4) The pulse generation circuit 59 is the duty ratio calculator 57
The pulse generation circuit 60 outputs a pulse signal m having an on-duty ratio Don calculated by the off-duty ratio Don calculated by the pulse generating circuit 60.
A pulse signal n having Doff is output. however,
The pulse signals m and n outputted from the pulse generation circuits 59 and 60 only change in duty ratio and have a constant period.

Motor 61a that constitutes vacuum pump 61
operates while the pulse signal m is "1" and moves the diaphragm 61b in the vertical direction. Then, by moving the diaphragm 61b in the vertical direction, the air inside the actuator 63 is exhausted, and the rod 63b attached to the diaphragm 63a moves in the axial direction, so that the throttle valve 64
The opening degree increases. That is, the vacuum pump 61
is for increasing the opening degree of the throttle valve 64 at a rate of change according to the on-duty ratio Don of the pulse signal m.

Further, the pulse signal of the valve 62b constituting the air valve 62 becomes "1", and the solenoid 62a is energized, thereby closing the intake hole 62c, and the pulse signal n becomes "0", and the excitation of the solenoid 62a is cut off. This opens the intake hole 62c and allows atmospheric air to enter the actuator 63.
Therefore, the pulse signal n becomes "0", and the intake hole 6
By opening 2c, the diaphragm 63
The rod 63b attached to a moves in the axial direction, and the opening degree of the throttle valve 64 decreases. That is, the air valve 62 reduces the opening degree of the throttle valve 64 at a rate of change depending on the off-duty ratio Doff of the pulse signal n.

Here, the on-duty ratio of pulse signals m and n is
Don and the off-duty ratio Doff change as shown in FIG. 6 according to the speed difference ΔV, and the on-duty ratio Don and the off-duty ratio change the rate of increase and the rate of decrease in the opening degree of the throttle valve 64, respectively.
Since it changes depending on Doff, by adopting the configuration shown in FIG. 5, it is possible to make the actual vehicle speed V match the target vehicle speed Vm.

However, in the conventional example described above, the periods of the pulse signals m and n are set to fixed values, and therefore the following problems occur.

That is, since the vacuum pump 61 and the air valve 62 have a non-response time (the time from when the pulse signals m and n are applied until they actually operate), the periods of the pulse signals m and n are fixed values. Then, the on-duty ratio Don, the off-duty ratio
If Doff is small, the vacuum pump 61 and the air valve 62 will not operate, and as a result, linear constant-speed running control will not be performed, leading to problems such as hunting and poor running feeling. Now, for example, if the non-response time of the vacuum pump 61 is 20 msec and the period of the pulse signal m is 55 msec, then the on-duty ratio Don of the pulse signal m is 20 ÷ 55 × 100 = 36 (%) or less. , the vacuum pump 61 will not operate.

[Problem that the invention seeks to solve]

The present invention solves the above-mentioned problems, and its purpose is to enable linear constant-speed running control.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention, as shown in FIG. 1, includes a detection means 1 for detecting the speed of the vehicle, and an arithmetic means 2 for calculating the difference between the detection result of the detection means 1 and the target vehicle speed. and a first duty ratio calculation means 3 for calculating the duty ratio of a first pulse signal having a first period based on the calculation result of the calculation means 2; a second duty ratio calculation means 4 that calculates the duty ratio of a second pulse signal having a period; an actuator 63 that sets the opening degree of the throttle valve 64 to an opening degree corresponding to the internal pressure; a vacuum pump 61 that reduces the pressure at a rate of change corresponding to the duty ratio calculated by the first duty ratio calculation means 3; Air valve 6 that increases at a rate of change corresponding to the duty ratio
2, in which the pulse of the first period corresponds to the duty ratio calculated by the first duty ratio calculation means 3 and the non-response time of the vacuum pump 61; By comparing the duty ratio in the signal,
Judgment for determining whether or not the vacuum pump 61 operates when the first cycle pulse signal having the duty ratio calculated by the first duty ratio calculation means 3 is applied to the vacuum pump 61. means 5, and when the determining means 5 determines that the vacuum pump 61 operates, the pulse signal of the first period having the duty ratio calculated by the first duty ratio calculating means 3 is applied to the vacuum pump 61; In addition to the vacuum pump 61, if the determining means 5 determines that the vacuum pump 61 does not operate, the on time or off time is longer than the non-response time of the vacuum pump 61, and the first duty ratio a first pulse signal outputting means 6 which applies a pulse signal having a duty ratio calculated by the calculating means 3 to the vacuum pump 61; and a first pulse signal outputting means 6 having a duty ratio calculated by the second duty ratio calculating means 4. A second pulse signal output means 7 for applying a pulse signal having a period of 2 to the air valve 62 is provided.

〔Example〕

FIG. 2 is a block diagram of an embodiment of the present invention, in which 11 is a microprocessor, 12 is a memory,
13 is an input section, 14 is an output section, 15 is an AD converter, 16 and 17 are amplifiers, 18 is a brake switch that is turned on when the brake pedal is depressed, 1
9 is a reset switch for canceling constant speed running, and the same reference numerals as in FIG. 5 represent the same parts. Further, FIG. 3 is a flowchart showing part of the processing contents of the microprocessor 11, and the operation of FIG. 2 will be explained below with reference to the same figure.

As in the conventional example shown in FIG. 5, the differential amplifier 56 calculates the speed difference ΔV= between the actual vehicle speed V and the target vehicle speed Vm.
Outputs a voltage proportional to Vm-V, AD converter 1
5 performs AD conversion on the output voltage of the differential amplifier 56 and applies it to the input section 13 . The microprocessor 11 performs the processing shown in the flowchart of FIG. 3 at predetermined intervals, and when it reads the output of the AD converter 15, that is, the speed difference ΔV, applied via the input section 13 in step S1, Determine whether the read speed difference ΔV is positive or negative (step S2,
3).

If the determination result in step S2 is YES, that is, if the actual vehicle speed V is slower than the target vehicle speed Vm, the microprocessor 11 controls the on-duty control of the pulse signal a according to the speed difference ΔV, as in the conventional example described above. The ratio Don is determined (step S4).
That is, in step S4, the microprocessor 11 adjusts the on-duty ratio Don if ΔV<V1.
is set to 100%, when ΔV>V2, the on-duty ratio Don is set to 0%, and when V1≦ΔV≦V2, the on-duty ratio Don of the pulse signal a is determined by performing the calculation shown in equation (1) above. [See Figure 6].

After finding the on-duty ratio Don of the pulse signal a in step S4, the microprocessor 11 compares the on-duty ratio Don found in step S4 with a first reference value D1 set in advance,
It is determined whether the relationship Don<D1 is satisfied (step S5). Here, the first reference value D
1 is determined by the period t1 of the pulse signal a and the non-response time tx of the vacuum pump 61. For example, if the period t1 is 55 msec and the non-response time tx is
If it is 20msec, the first reference value D1 is D1
=tx÷t1×100=36% (see Figure 4). That is, in step S5, it is determined whether or not the vacuum pump 61 operates when the pulse signal a with the period t1 having the on-duty ratio Don determined in step S4 is applied to the motor 61a.

If the judgment result in step S5 is NO, that is, the on-duty ratio obtained in step S4 is
As shown in FIG. 4A, the on time of the pulse signal with period t1 having Don (the time when the signal becomes "1" in one cycle of the pulse signal) is longer than the non-response time tx of the vacuum pump 61. , if it is determined that the vacuum pump 61 can be operated, the microprocessor 11 calculates Ton=t1×Don.
The on-time Ton of the pulse signal a is obtained by performing the following calculation (step S6), and then Toff=
The off-time Toff of the pulse signal a (the time when the pulse signal a becomes "0" in one cycle of the pulse signal a) is obtained by performing the calculation t1-Ton (step S7), and then the output section 14 is controlled to A pulse signal a having the on and off times Ton and Toff obtained in steps S6 and S7 is output from the output section 14.
At the same time, the pulse signal b is held at "1" (steps S11 and 12), and the process then proceeds to other control steps (step S22). In addition, when the vacuum pump 61 receives the pulse signal a via the amplifier 16, it exhausts the air inside the actuator 63 and moves the rod 63b in the axial direction, thereby increasing the on-duty ratio of the pulse signal a.
Throttle valve (not shown) at a rate of change according to Don
Increase the opening. At this time, since the pulse signal b is held at "1" in step S12, the intake hole 62c is closed by the valve 62b.

Furthermore, if the judgment result in step S5 is YES,
That is, the on-duty ratio Don obtained in step S4
As shown in FIG. 4B, the on time of the pulse signal with the period t1 (the time during which the signal becomes "1" in one period of the pulse signal) is shorter than the non-response time tx of the vacuum pump 61, If it is determined that the vacuum pump 61 cannot be operated, the on-time Ton is set to a preset time t2.
(Step S8). Note that the time t2 needs to be longer than the non-response time tx of the vacuum pump 61. Next, the microprocessor 11 finds an integer N of 2 or more that satisfies the following equation (5) (step S9).

t2÷(t1×Don)+1>N≧t2÷(t1×Don)
(5) Next, the microprocessor 11 calculates the off time Toff of the pulse signal a by performing the calculation shown in the following equation (6) (step S10).

Toff=(t1-t2)+t1(N-1)...(6) Next, the microprocessor 11 outputs the output section 1
A control signal is added to step S from the output section 14.
A pulse signal a as shown in FIG. 4C having the on and off times Ton and Toff obtained in steps 8 and 10 is outputted, and the pulse signal b is held at "1" (steps S11 and 12). The process moves on to other control steps (step S22). In this case, the off-time Toff is calculated using equations (5) and (6), but it is of course possible to calculate the off-time Toff by performing the calculation shown in the following equation (7). It is.

Toff=t2÷Don-t2...(7) Also, if the judgment result in step S3 is YES,
That is, if the actual vehicle speed V is faster than the target vehicle speed Vm, the microprocessor 11 determines the off-duty ratio Doff of the pulse signal b according to the speed difference ΔV, as in the conventional example described above (step S13). That is, in step S13, the microprocessor 11 sets the off-duty ratio Doff to 0% when ΔV<V3, and sets the off-duty ratio Doff to 0% when ΔV>V4.
When Doff is 100% and V3≦ΔV≦V4, the off-duty ratio Doff is determined by performing the calculation shown in equation (2) above [see FIG. 6].
If the results of the determinations in steps S2 and S3 are both NO, the microprocessor 11 moves on to other control steps (step S22).

When the off-duty ratio Doff of the pulse signal b is determined in step S13, the microprocessor 11
is the off-duty ratio obtained in step S13
Doff is compared with a preset second reference value D2, and it is determined whether the relationship Doff<D2 is satisfied (step S14). Here, the second reference value D2 is determined by D2=ty÷t3×100, where t3 is the period of the pulse signal b and ty is the non-response time of the air valve 62. That is, in step S14, the period t3 having the off-duty ratio Doff obtained in step S13 is determined.
When the pulse signal b is applied to the solenoid 62a, it is determined whether or not the air valve 62 operates.

If the determination result in step S14 is NO, that is, the off time of the pulse signal b with the period t3 having the off duty ratio Doff determined in step S13 is longer than the non-response time ty of the air valve 62, and the air valve 62 is operated. If it is determined that the microprocessor 11 can
By performing the calculation Toff′=t3×Doff,
The off-time Toff' of the pulse signal b is determined (step S15), and then the on-time Ton' of the pulse signal b is determined by performing the calculation Ton'=t3-Toff' (step S16). A signal is added, and the output section 14 outputs the signal in step S15.
The pulse signal b with the period t3 having the off-duty ratio Doff obtained in step S16 is output, and the pulse signal a is held at "0" (step S20,
21), and then moves to another control step (step S22).

Further, if the determination result in step S14 is YES, that is, the off time of the pulse signal b with the period t3 having the off duty ratio Doff determined in step S13 is shorter than the non-response time ty of the air valve 62, and the air valve 62 is operated. If it is determined that this is not possible, the off time Toff' is set to a preset time t4 (step S17).
Note that the time t4 is the non-response time ty of the air valve 62.
It is necessary that the time is longer than that. Next, the microprocessor 11 finds an integer N of 2 or more that satisfies the following equation (8) (step S18).

t4÷(t3×Doff)+1>N≧t4÷(t3×Doff)
(8) Next, the microprocessor 11 calculates the on-time Ton' of the pulse signal b by performing the calculation shown in the following equation (9) (step S19).

Ton'=(t3-t4)+t3(N-1)...(9) Next, the microprocessor 11 outputs the output section 1.
A control signal is added to step S from the output section 14.
On and off times Ton′ obtained in 17 and 19,
While outputting a pulse signal b having Toff',
The pulse signal a is held at "0" (step S2
0, 21), then the process moves to other control steps (step S22). In this case, equations (8) and (9)
Although the on-time Ton′ was calculated using the following equation (10), the off-time
Of course, it is also possible to find Ton′.

Ton'=t4÷Doff-t4...(10) In this way, in this embodiment, the on-time Ton of the pulse signal a with the period t1 having the on-duty ratio Don determined in step S4 is the non-response time of the vacuum pump 61. If it is shorter than the no-response time tx, the on-duty ratio of the pulse signal a is set by setting the on-time of the pulse signal a to be longer than the no-response time tx (step S8) and performing the processing of steps S9 and 10.
The off-time Toff' of the pulse signal b with the period t3 having the off-duty ratio Doff obtained in step S13 is the non-response time ty of the air valve 62.
If it is shorter than , the off time of pulse signal b
By setting Toff' to be longer than the non-response time ty (step S17) and performing the processing in steps S18 and 19, the off-duty ratio Doff of the pulse signal b is determined to be the one obtained in step S13. On-duty ratio Don and off-duty ratio, which were not controlled at all in the past
Control is performed even in a small region of Doff, thus making it possible to perform fine constant speed driving control.

Although not explained in the above embodiment, the brake switch 18 and the reset switch 1
9 is turned on, the microprocessor 11
This ends the process shown in the flowchart of FIG. In addition, in the above-described embodiment, the period changing process (steps S8 to S10, steps S17 to S19) is performed on both pulse signals a and b, but the non-response time ty of the air valve 62 is the same as that of the vacuum valve 61. Since the response time tx is small compared to the response time tx, it is practically sufficient to perform the above-described processing only on the pulse signal a.

〔Effect of the invention〕

As explained above, the present invention provides a detection means for detecting the speed of a vehicle (in the embodiment, it consists of a reed switch 51, a permanent magnet 52, etc.), and a difference between the detection result of the detection means and the target vehicle speed. [In the embodiment, it consists of a differential amplifier 56]
and a first step for determining the duty ratio of a first pulse signal [pulse signal a in the embodiment] having the first period [t1 in the embodiment] based on the calculation result of the calculation means. A duty ratio calculation means (in the embodiment, this is realized by performing the process of step S4 in the microprocessor 11), and a second period (t3 in the embodiment) is calculated based on the calculation result of the calculation means. A second duty ratio calculation means (in the embodiment, the microprocessor 11 performs step S) for calculating the duty ratio of the second pulse signal (pulse signal b in the embodiment) having
13], an actuator that sets the opening degree of the throttle valve to an opening degree corresponding to the pressure inside the throttle valve, and the pressure inside the actuator calculated by the first duty ratio calculation means. An automobile comprising: a vacuum pump that reduces the pressure in the actuator at a rate of change corresponding to the duty ratio; and an air valve that increases the pressure in the actuator at a rate of change that corresponds to the duty ratio calculated by the second duty ratio calculation means. In the constant speed traveling device, the first period corresponds to the duty ratio calculated by the first duty ratio calculation means and the non-response time [tx in the embodiment] of the vacuum pump. By comparing the duty ratio in the pulse signal, when the pulse signal of the first period having the duty ratio calculated by the first duty ratio calculation means is applied to the vacuum pump, the vacuum pump Judgment means for judging whether or not the pump operates [In the embodiment, this is realized by performing the process of step S5]
and when the determining means determines that the vacuum pump operates, applying a pulse signal of the first period having the duty ratio calculated by the first duty ratio calculating means to the vacuum pump; If the judgment means determines that the vacuum pump does not operate, the on means or the off means (on time Ton in the embodiment) is longer than the non-response time of the vacuum pump, and the first a first pulse signal output means for applying a pulse signal having a duty ratio calculated by the duty ratio calculation means to the vacuum pump;
and second pulse signal output means for applying a pulse signal of the second period having the duty ratio calculated by the duty ratio calculation means to the air valve. Since it is possible to perform duty ratio control even in a small duty ratio region, there is an advantage that fine and stable constant speed traveling control can be performed.

[Brief explanation of the drawing]

1 is a block diagram of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, FIG. 3 is a flowchart showing the processing contents of the microprocessor 11, and FIG. 4 is an explanation of the operation of FIG. 2. 5 is a block diagram of the conventional example, and FIG. 6 is a diagram showing the relationship between speed difference ΔV and on/off duty ratio. 1 is a detection means, 2 is a calculation means, 3 and 4 are first and second duty ratio calculation means, respectively, 5 is a judgment means, 6 and 7 are first and second pulse signal output means, respectively, and 11 is a micro Processor, 12 is memory, 13 is input section, 14 is output section, 15 is AD
Converter, 16 and 17 are amplifiers, 18 is a brake switch, 19 is a reset switch, 51 is a reed switch for detecting vehicle speed, 52 is a permanent magnet, 53 is a frequency voltage converter (FV converter), 54 is an analog switch, 55 is a memory circuit, 56 is a differential amplifier,
57 and 58 are duty ratio calculators, 59 and 60 are pulse generation circuits, 61 is a vacuum pump, and 61
a is a motor, 61b is a diaphragm, 61c, 6
1d is a valve, 62 is an air valve, 62a is a solenoid, 62b is a valve, 62c is an intake hole, 63 is an actuator, 63a is a diaphragm, 63b is a rod, 64 is a throttle valve, and 65 is a set switch.

Claims (1)

[Scope of Claims] 1. Detection means for detecting the speed of the vehicle; Calculation means for calculating the difference between the detection result of the detection means and the target vehicle speed; and a first period based on the calculation result of the calculation means. a first duty ratio calculation means for calculating the duty ratio of a first pulse signal; and a second duty ratio calculation means for calculating the duty ratio of a second pulse signal having a second period based on the calculation result of the calculation means. means, an actuator for adjusting the opening degree of the throttle valve to an opening degree corresponding to the pressure inside the throttle valve, and reducing the pressure inside the actuator at a rate of change corresponding to the duty ratio calculated by the first duty ratio calculation means. a vacuum pump for increasing the pressure in the actuator, and an air valve for increasing the pressure in the actuator at a rate of change corresponding to the duty ratio calculated by the second duty ratio calculation means, By comparing the duty ratio calculated by the first duty ratio calculation means and the duty ratio in the pulse signal of the first period corresponding to the non-response time of the vacuum pump, the first duty ratio is calculated. determining means for determining whether or not the vacuum pump operates when the first cycle pulse signal having the duty ratio calculated by the duty ratio calculation means is applied to the vacuum pump; When it is determined that the vacuum pump operates, the first vacuum pump having the duty ratio calculated by the first duty ratio calculating means
applying a pulse signal with a period of
and a first pulse signal output means for applying a pulse signal having a duty ratio calculated by the first duty ratio calculation means to the vacuum pump; and a first pulse signal output means for applying a pulse signal having a duty ratio calculated by the second duty ratio calculation means and second pulse signal output means for applying a pulse signal having the second period to the air valve.