JPS6220044B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a constant speed driving control method for an automobile with a speed limit that prevents the vehicle from driving at a constant speed exceeding a predetermined maximum speed. be.

[Conventional technology]

Conventionally, in this type of constant speed vehicle driving device, in order to drive at a constant speed, the set speed set by the driver's set operation is the so-called vehicle limit speed, that is, the predetermined maximum speed. To ensure safety, constant speed control is disabled when the speed exceeds the limit.

[Problem that the invention seeks to solve]

Therefore, in the conventional system, in order to set the constant speed running state when the set speed is higher than the speed limit, the set speed must be adjusted to be below the speed limit and then reset. It was necessary and extremely inconvenient to handle.

The present invention has been made to eliminate this inconvenience, and even when the set speed is higher than the speed limit, it can be operated without the need for troublesome operations.
The purpose is to automatically maintain a constant speed at a safe speed.

[Means for solving problems]

Therefore, in order to achieve the above object, the present invention provides a constant speed driving control method for an automobile that performs control to maintain the driving speed of the automobile at a target speed. Compare the set speed with the set speed limit of the vehicle, and when the set speed is below the speed limit,
A technical means is employed in which the set speed is set as the target speed, and when the set speed is greater than the control speed, the limit speed is set to the target speed regardless of the set speed.

[Example] An example of an apparatus to which the method of the present invention is applied is shown in the accompanying drawings.

Reference numeral 1 indicates a set switch having a normally open contact, and once the switch is closed, the vehicle speed becomes the constant speed of the vehicle. 2 is a cancel switch that has a normally open contact and is linked to the brake or clutch, and is closed when the brake or clutch is stepped on. Reference numeral 80 denotes a rigidity set switch, which is used to return to constant speed running at the previous vehicle speed after the vehicle has been cancelled. 3 is a reed switch that generates a pulse proportional to the vehicle speed, and is opened and closed by a magnet that rotates in conjunction with the rotating shaft of the speedometer. 4 is an on-vehicle storage battery that serves as a power source for the entire device. 5 is a frequency-voltage conversion circuit that outputs a DC voltage proportional to the opening/closing frequency of the reed switch 3, that is, the vehicle speed, and is connected to resistors 6, 7,
8, capacitors 9, 10, diodes 11, 12
It becomes more.

Resistors 13 and 14 have resistance values of resistance 13 << resistance 14.
The emitter follower is configured together with the transistor 15, and serves as a buffer for impedance conversion. Also, resistor 13 and resistor 1
6 and 17 determine the initial opening degree of the throttle valve 18. Here, the initial opening degree is the opening degree of the throttle valve 18 that is determined corresponding to the vehicle speed at the time of setting. The capacitor 19 is a capacitor that stores a voltage value corresponding to the set vehicle speed, and one end is connected to a high input impedance field effect transistor (hereinafter referred to as
23 gate (referred to as FET) and the voltage dividing resistor 1 for setting the initial opening through the relay contact 20.
6 and 17, and the other end is connected to the connection point between the emitter of the transistor 15 forming the emitter follower and the resistor 14.

Reference numeral 21 denotes a throttle opening detector consisting of a sliding resistance that is linked to the opening and closing of the throttle valve 18 and detects the degree of opening and closing as a voltage value.The arrow A direction is the closing direction of the throttle valve 18, and the arrow B direction is the throttle opening detector 21 This is the opening direction.

22 is a control means for controlling the opening degree of the throttle valve 18. The resistors 24 and 25 constitute a source follower together with the FET 23, and the amount of change in vehicle speed is output as a voltage value. The resistance values of the voltage dividing resistors 24 and 25 are as follows: 24<<25, and voltages with slightly different levels are output to the source terminal of the FET 23 and the connection point between the voltage dividing resistors 24 and 25.

26 and 44 are comparators, one of whose input terminals receives the voltages having the different levels, and the other input terminal of which is connected to a throttle opening detector 21 that feeds back the opening of the throttle valve 18. The comparator 26 outputs a high level output when the detected vehicle speed is greater than the throttle opening amount, and the comparator 44 outputs a high level output when the detected vehicle speed is smaller than the throttle opening amount. Note that voltages with different levels are input to one of the inputs of the comparators 26 and 44 due to the resistors 24 and 25, so both comparators output high level outputs in response to changes in vehicle speed. A so-called dead zone is provided, which is a range in which this phenomenon does not occur.

Resistors 27, 28 and transistors 29, 30 constitute an output amplification circuit of comparator 26, and diode 31 is for surge absorption. In addition, resistor 45,
46, 47, transistors 48, 49 are comparator 4
It forms the output amplification circuit of 4, and the diode 50
is for surge absorption. Diodes 51 and 52 connect the outputs of comparators 26 and 44 to the amplification stage only when a flip-flop circuit 61, which will be described later, is set.

Reference numeral 53 denotes a three-brush motor that serves as an actuator for opening and closing the throttle valve 18. When the aforementioned transistor 30 is conductive, it operates in the direction of opening the throttle valve 18 to increase the vehicle speed, and when the aforementioned transistor 49 is conductive, the throttle valve 18 is opened and closed. 1
8 in the direction of closing to reduce the vehicle speed. 5
4 is energized only when the flip-flop circuit 61 (to be described later) has a set output, and the 3-brush motor 53
This is an electromagnetic clutch that connects the throttle valve 18 and the throttle valve 18. Here, the connection between the three-brush motor 53 and the throttle valve 18 is such that when accelerating, the throttle valve 1
8 in the opening direction, and when decelerating, the throttle valve 18 is closed by a return spring (not shown). Although not shown, the throttle valve 18 is connected to an accelerator mechanism operated by the driver, so that the throttle valve 18 can be freely accelerated by operating the accelerator mechanism.

Resistors 55, 56 and transistor 57 serve as an interface between set input terminal S1 of flip-flop circuit ₆₁ and the set switch 1, and resistor 8
2, 83 and transistor 81 are the interface between the set input terminal S ₂ of flip-flop circuit 61 and the above-mentioned bulk set switch 80.
Resistors 58, 59 and transistor 60 are an interface between reset input terminal R of flip-flop circuit 61 and cancel switch 2.
The flip-flop circuit 61 is composed of three NOT gates 61a, 61b, 61e, two NAND gates 61c, 61d, and an OR gate 61f, and when the set switch 1 or the resume set switch 80 is closed, the set output terminal Q is When the cancel switch 2 is closed, the output at the set output terminal Q becomes low level. As mentioned earlier, when the set switch 1 is turned on, the resistors 56 and 4
The base current flows through transistor 4
3 becomes conductive, an exciting current flows through the exciting coil 42, and the relay contact 20 is closed. 41 is a diode for protection against reverse bias between the base and emitter of the transistor 43;

32 and 33 are voltage dividing resistors that set a voltage value corresponding to the high speed limit, and when manufacturing the circuit shown in the drawing, it is necessary to set the voltage value corresponding to the high speed limit of an expressway, for example.
It is preset to generate a voltage corresponding to 100 km/h. 34 is a comparator that compares the voltage set by the voltage dividing resistors 32 and 33 with the output voltage of the frequency-voltage conversion circuit 5; when the output voltage of the conversion circuit 5 is smaller than the voltage set by the voltage dividing resistors 32 and 33, produces a level output signal. 35 is an input resistor, and 36 is a resistor for providing hysteresis characteristics to the operation of the comparator 34.

A diode 37 forcibly shorts the throttle opening detector 21 when the comparator 34 generates a low level output signal. 38 is a capacitor, and 39 is a resistor, both of which constitute a differentiating circuit that momentarily turns on transistor 43 when comparator 34 produces a high-level output signal.

The excitation coil 42 is energized only when the transistor 70 serving as the inhibiting means is conductive, that is, when the flip-flop circuit 61 is in the set state. In other words, under normal running conditions when the flip-flop circuit 61 is not set, the excitation coil 42 is prevented from being excited even if the vehicle speed exceeds the high speed limit.

71 and 72 are bias resistances of the transistor 70.

The operation of the above configuration will be explained. If the vehicle is currently traveling at a high speed within the speed limit, the reed switch 3 opens and closes at a frequency corresponding to the speed. The frequency-voltage conversion circuit 5 converts it into a DC voltage proportional to the running speed, and the emitter terminal of the transistor 15 has a resistance value of 13 ≪ resistance value 1
4, a vehicle speed voltage is generated that is lower than the output voltage of the frequency-voltage conversion circuit 5 by the base-emitter voltage of the transistor 15 (usually about 0.7V). on the other hand,
The collector voltage of the transistor 15 decreases as the vehicle speed increases, and this collector voltage is applied to the resistor 16.
The divided voltage divided by the resistor 17 is the capacitor 19
is applied to one end of

When set switch 1 is turned on (once closed and then opened) in this standby state, base current flows through resistor 56 and resistor 40 to transistor 43, making it conductive, current flows through exciting coil 42, and relay contact 20 closes. Closed, a voltage corresponding to the initial opening is generated at the source of the FET 23. Furthermore, since the flip-flop circuit 61 produces a high-level output at the set output terminal Q at the same time as the set switch 1 is turned on, the outputs of the comparators 26 and 44 are transmitted to the amplification stage by the diodes 51 and 52 before the set switch 1 is turned on. Release the state where it was prohibited. Further, since a high level output is generated at the set output terminal Q of the flip-flop circuit 61, the magnetic clutch 54 is operated and the three-brush motor 53 and the throttle valve 18 are operated.
Connect with. Note that the flip-flop circuit 61
Since the reset output terminal of is at a low level, a forward bias is applied to the transistor 70, and the excitation coil 4 is
Do not interfere with the operation of 2.

In this state, a voltage corresponding to the initial opening degree is stored at one end of the storage capacitor 19, and a voltage corresponding to the vehicle speed is stored at the other end. Since the FET 23 and the resistors 24 and 25 constitute a source follower, the source voltage is determined by the gate voltage of the FET 23, and this source voltage becomes the initial opening voltage, resulting in a constant speed running state.

Comparators 26 and 44 are throttle opening detector 21
The voltage from the throttle opening detector 21 is higher than the voltage corresponding to the vehicle speed, so if the opening of the throttle valve 18 is small, the comparator 26 indicates a high level. , comparator 4
4 produces a low level output. Therefore, the transistor 30 becomes conductive, and the three-brush motor 53 operates in the direction of opening the throttle valve 18, increasing the opening degree of the throttle valve 18.

Resistor 24,2 connected to the source of FET23
5 provides a slight level difference between the inputs of the comparators 26 and 44, so when the comparison input falls within this level difference range, the comparators 26 and 44
The motor enters a so-called dead zone in which no high-level output is produced in any of the three-brush motors 44, and the three-brush motor 53 stops operating.

If the vehicle speed increases for some reason from this state, the output voltage of the frequency-voltage conversion circuit 5 will also increase.
The emitter voltage of transistor 15 also increases. By this increase, FET2 of the memory capacitor 19
When the potential on the 3 side also rises and the + input voltage corresponding to the vehicle speed becomes higher than the detection voltage of the throttle opening detector 4, the comparator 44 produces a high level output, and the 3 side
The brush motor 53 operates in a direction to close the throttle valve 18. As the throttle valve 18 closes, the detection voltage of the throttle opening detector 4 also decreases, and the three-brush motor 53 operates until the output of the comparator 44 changes to a low level and enters the dead zone. In this way, the vehicle speed is reduced to the vehicle speed set when the set switch 1 was turned on. Note that the above description is for the case where the vehicle speed increases from the set vehicle speed, but if the vehicle speed decreases, the comparator 26 is activated and the vehicle speed is returned to the set vehicle speed in the same way.

Next, a case will be described in which the set switch 1 is turned on when the vehicle speed is higher than the high speed limit. Due to the setting of flip-flop circuit 61, transistor 70 is naturally conductive. The set voltage value corresponding to the high speed limit is determined by the value obtained by dividing the power supply voltage by the resistors 32 and 33. When the output voltage of the frequency-voltage conversion circuit 5 is higher than this voltage value, the comparator 34 Produces a low level output signal. As a result, the diode 37 forcibly lowers the output of the throttle opening detector 4 to a low level, making it appear as if the throttle valve 18 had opened, and therefore the comparator 44 is activated.
The three-brush motor 53 is operated in the direction of fully closing the throttle valve 18. As a result, the vehicle speed decreases, and when the vehicle speed decreases to the high speed limit, the comparator 3
The output of 4 turns to high level. When the output of the comparator 34 becomes high level, the capacitor 38 and the resistor 39
A base current flows through the transistor 43 and becomes conductive, causing a current to flow through the excitation coil 42 for a moment.
During this time, the relay contact 20 closes and the capacitor 19 stores the vehicle speed at that time, that is, the maximum vehicle speed limit, as a voltage value corresponding to the initial opening degree, and therefore the vehicle starts running at a constant speed at the high speed limit. In addition, the resistor 36
Since a hysteresis characteristic is imparted to the high speed limit, the comparator 34 can perform a stable comparison operation in the same manner as the dead zone described above even when traveling at a constant speed at the high speed limit.

The above is the operation when the set switch 1 is turned on when the vehicle speed is above the high speed limit, but when the vehicle is traveling at a constant speed close to the high speed limit, the vehicle speed suddenly increases just as it is going downhill. Even if the vehicle exceeds the high-speed limit, it operates in the same way, allowing the vehicle to travel at a constant speed at the high-speed limit.

Next, in the case of a resume setting, when the resume setting switch 80 is turned on (once closed and then opened), the flip-flop circuit 61 is set. However, since the flip-flop circuit 61 had been reset before this, the memory in the memory capacitor 19 has not been changed, and the vehicle runs at a constant speed using the previously set memory value as the set value. That is, since the transistor 70 is turned on or off depending on the output state of the flip-flop circuit 61, the transistor 70 is turned on or off when the vehicle is not running at a constant speed.
0 is cut off, and the stored value of the storage capacitor 19 is not changed when the high speed limit is exceeded once and then the speed returns below the high speed limit.
This is indispensable for constant speed traveling devices with a resume set function to prevent malfunctions.

In the above-described embodiment, the vehicle speed setting means is the capacitor 19 that stores a voltage value corresponding to the initial opening degree of the throttle valve 18 at the time of setting, and the vehicle speed detection means detects the opening degree of the throttle valve 18 as a voltage value. The throttle opening detector 21 was configured to drive the vehicle at a constant speed by operating the control means 22 to reduce the deviation between the voltage values of both means. A vehicle speed setting means that sets a voltage value correspondingly, a vehicle speed detection means that detects a voltage value corresponding to the actual vehicle body from a rotating body such as a wheel of the automobile, and a differential amplifier or the like is used to detect the deviation between the voltage values of both means. Even if the constant speed traveling device is equipped with a control means that amplifies the differential and controls the throttle valve based on the output thereof, the constant speed traveling device is also equipped with a vehicle speed detection means that electrically detects the engine rotation speed as the actual vehicle speed. The present invention can be similarly applied to such cases.

In addition, in the above embodiment, two fixed resistors 32 and 33 are used to preset the high speed limit, but if a variable resistor such as a sliding resistor is used instead, it is possible to manufacture the circuit. Sometimes the preset resistance value can be changed by the dealer or the driver. For example, if the variable resistor is placed close to the set switch 1, the driver can change the resistance value setting of the variable resistor depending on the road.
It becomes possible to change the high speed limit from 100 km/h to 80 km/h, for example. Therefore, the maximum travel speed at which constant speed travel is possible can be freely changed depending on the road.

In addition, in the embodiment, the three-brush motor 53 is used as an actuator for driving the throttle valve 18, but the engine oil pressure or intake negative pressure is switched by a solenoid valve, and the diaphragm is actuated by the engine oil pressure or intake negative pressure. An actuator may be used to drive the throttle valve 18.

As described above, according to the present invention, even if the speed of the vehicle is higher than the speed limit, once the set operation is performed, the vehicle can be set safely regardless of the set speed without requiring any troublesome operations by the driver. Since it is possible to drive at a constant speed using a certain speed limit as the target speed, it is extremely easy to handle and has excellent effects in contributing to safe driving.

[Brief explanation of the drawing]

The accompanying drawing shows an electrical wiring diagram showing one embodiment of a constant speed traveling device for an automobile to which the present invention is applied. DESCRIPTION OF SYMBOLS 1... Set switch, 2... Cancel switch, 3... Reed switch, 5... Frequency-voltage converter circuit forming a main part of vehicle speed detection means, 18... Throttle valve, 19, 20... Main part of vehicle speed setting means Memory capacitor and relay contact, 21...
Throttle opening degree detector, 22...control means, 3
2, 33...Resistance serving as maximum vehicle speed setting means, 34
...Comparator forming the main part of the comparison means, 37...Diode forming the operating means, 42, 43...Exciting coil and transistor forming the main part of the reset means, 6
1, 70...Flip-flop circuit and transistor forming the main part of the inhibiting means, 80...Rigidium set switch.

Claims (1)

[Scope of Claims] 1. A constant speed driving control method for an automobile that maintains the driving speed of the automobile at a target speed, which includes: a set speed set by an occupant's set operation and a preset speed limit of the automobile. When the set speed is less than the speed limit,
A method for controlling constant speed driving of an automobile, characterized in that the set speed is set as the target speed, and when the set speed is greater than the speed limit, the speed limit is set to the target speed regardless of the set speed. .