JPS6018426A - Constant speed drive equipment of automobile - Google Patents

Abstract

PURPOSE:To prove stable control of constant speed driving in an equipment which controls the displacement of a bellows so as to adjust the opening of a throttle valve by providing the equipment with a controller which compensates the variation in gain of the bellows according to variation of negative pressure of intake air. CONSTITUTION:When a controller 1 memorizes a certain car speed as a set value, the titled equipment operates for the purpose of maintaining the speed, at which a car is driving, at the set value. Namely, the equipment has a for-deceleration solenoid valve 2 or a for-acceleration solenoid valve 3 actuated to control the displacement of a bellows 4 for adjusting the opening of a throttle valve 5. A pressure sensor 9 which detects a negative pressure of intake air is disposed on the way of a negative pressure pipe 7 which connects an intake manifold 6 to the for-acceleration solenoid valve 3, and sends an electric signal proportional to the intake negative pressure to the controller 1. The detected value P of the intake negative pressure is compared with a specified value P0 in the controller 1 and it compensates the gain of the bellows 4. In case of P<P0, it makes the gain thereof lower than the reference gain and in case of P>P0, it makes the gain higher than that.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a constant speed driving system for an automobile that controls throttle valve opening, and more particularly to a control technique that compensates for control r-in fluctuations.

Generally, a constant speed traveling device is a device that controls the opening degree of a throttle valve in order to maintain a constant vehicle speed instructed by a driver.

Conventionally, there has been a device of this type as shown in FIG. In the figure, l is a constant speed traveling device control unit (hereinafter referred to as the control unit), 2 is a deceleration electromagnetic valve (hereinafter referred to as VENT), and 3
4 is an electromagnetic valve for speed increase (hereinafter referred to as VAC), and 4 is a bellows that drives the throttle valve 5. The entire pressure-receiving part is made of oil-resistant cloth-filled rubber, and is configured to respond to the differential pressure between internal pressure and atmospheric pressure. There is. 6 is an intake manifold that communicates the throttle valve 5 with the engine 8, and 7 is a negative pressure pipe that guides the negative pressure generated within the intake manifold 6 to the VAC 3.

In the above configuration, when the control unit 1 stores the vehicle speed as the set vehicle speed, it must maintain the current vehicle speed at the set vehicle speed (
V, ENT 2 or VAC3' (c activated, Perot r
4] Adjust the opening degree of the throttle valve 5 by controlling the movement i. By the way, the vehicle speed increases when the throttle valve 5 is opened, and decreases when the throttle valve 5 is closed. Therefore, for example, when the vehicle speed is lower than the set vehicle speed, the control unit 1 opens the throttle valve 5 to increase the speed by turning the KVAC 3 ONL and directing the negative pressure generated in the intake manifold 6 to the negative pressure pipe 7 and the VA.
C3 is introduced into the bellows 4, and the internal pressure of the bellows 4 is lowered to below atmospheric pressure, thereby compressing the bellows 4.

Conversely, when the vehicle speed is higher than the set vehicle speed, the control section controls the throttle pulse 7'5 to close.
2 is ONL, the pressure inside the bellows 4 is set to atmospheric pressure through the VENT 2, and the bellows 4 is expanded. The control unit 1 detects the vehicle speed at regular intervals and controls VAC3 or VENT2 for 08 hours in order to correct the amount of change from the set vehicle speed. As described above, the constant speed traveling device can achieve the entire purpose of maintaining a constant vehicle speed.

In addition, the control amount of the throttle valve opening is Perot)! ″4
Since it depends on the amount of expansion and contraction of the bellows 4, there is no problem as long as the dyne (displacement speed) of the bellows 4 is constant. However, the dyne of the bellows 4 depends on the In manifold negative pressure value, and the intake manifold negative pressure value is affected by the throttle valve opening. Therefore, the gain of the bellows 4 varies depending on the throttle valve opening. for example.

In order to increase the engine output on an uphill road compared to a flat road, it is necessary to open the throttle valve larger.
On the other hand, on descending roads, it is necessary to reduce the throttle opening degree in order to reduce the engine output. On the other hand, as a characteristic of the engine 8, as the opening degree of the throttle valve 5 increases, the intake manifold negative pressure approaches the atmospheric side, and as the throttle valve opening degree decreases, the intake manifold negative pressure approaches the vacuum side. It should be noted that this same tendency also occurs with respect to changes in the magnitude of the engine load at a constant throttle pulse opening. Therefore, during constant speed control, the throttle and valve openings change in response to changes in the road gradient, and the intake manifold negative pressure also changes. When the intake manifold negative pressure approaches the atmospheric pressure side, the air pressure acting on the bellows 4 decreases, so the key of the bellows 4 becomes smaller, and when it approaches the vacuum side, the key increases. In the end, the gain of the bellows 4 fluctuates due to changes in load such as changes in road gradient.
The gain of the control loop of the constant speed traveling device fluctuates, making it difficult to obtain stable control.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and includes a pressure sensor that detects intake manifold negative pressure, and a control and valve operation for controlling bellows key fluctuation according to the detected value. The present invention provides a constant speed traveling device for an automobile that can always keep the loop dyne of the entire constant speed traveling device constant against changes in intake manifold negative pressure by having a configuration including a means for total time correction. It's all about money.

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

FIG. 2 shows one embodiment of the present invention. In the figure, a pressure sensor 9, for example, a semiconductor pressure sensor, is installed in the middle of a negative pressure pipe 7 connected from the intake manifold 6 to the VAC 3 to detect the negative pressure in the intake manifold. The electric signal proportional to the intake manifold negative pressure, which is the output thereof, is sent to the control section 1.

Based on the above configuration, the operation of an embodiment of the present invention will be described.

The control unit 1 compares the detected value of the pressure sensor 9 with a predetermined value. When the intake manifold negative pressure reaches the predetermined value, and the gain GB of bellows 4 is set to the reference gain GBO, (GB
= GBO), if the negative pressure in the intake manifold Y+" is lower than the predetermined value, that is, if it is a value on the atmospheric pressure side, the r in GB of the bellows 4 will be lower than the reference dyne GBO (
GB<Gx+o). Also, if the intake manifold negative pressure is higher than the predetermined value (X empty side), the r in GB of the bellows 4 will be higher than the reference gain GIIO (cB >
GBO). This situation is shown in a graph 75; 3rd
Figures (a) and (b). Therefore, the control unit 1 controls the r-in G of the bellows 4 to keep the dyne of the control loop constant.
B is multiplied by the modified gain Gce to obtain f.The control unit 1 selects the modified gain GCt so that the following equation 75 holds true.

QB□ = GC Here, GBo is given in advance, and the relationship between GB and the negative pressure side of the intake manifold is determined by the guide of the bellows 4.
This is known in advance as a horn characteristic. Figure 3
Se.

(C) shows the fluctuation of the correction gain GcO value in response to the fluctuation of the intake manifold negative pressure value as shown in Figure 3 (a), and Figure 3 (d) is obtained as the result of the above calculation. 1-13 Positive bellows gain G (=calculated Gc) also shows (So, naturally, G=GB,
becomes constant. Like li'ft1 and above, bellows 4
As a practical means of modifying the gain of the electromagnetic pulp 2 on the deceleration side, or 4° may be considered to modify the drive pulse width of the electromagnetic pulp 3 on the speed increasing side.For example, before modification If the width of the output pulse is T as shown in Fig. 4(a), then the correction gain G is applied to this component FT.
From the perspective of the bellows 4, the corrected output pulse width TC motion 1 ((b) in the same figure) multiplied by ee is equivalent to the fact that the dynes have been rust-prevented. 3 (In addition, in the example above, the case where a semiconductor is used as a pressure sensor is explained, but the same effect as in the above example can be obtained even if a pressure sensor for sound such as a capacitance type, an inductance type, or a resistance type is used. 71 According to the above-described system, the present invention includes a pressure sensor for detecting intake manifold negative pressure, and
With the control 1 that corrects the dyne fluctuation of the bellows 4 due to the intake manifold negative pressure change C based on the output of the engine, the constant speed running control becomes stable and the throttle opening degree changes due to changes in the road gradient. This has the great effect of being able to hold the dyne constant even when the speed is high, and providing a constant speed traveling device with a high nail speed.

[Brief explanation of the drawing]

Figure 1 shows the configuration of a conventional device, vJz diagram shows the composition of a constant speed vehicle for automobiles that is an example of this month's implementation, and Figure 3 shows the relationship between the gain and the intake manifold negative pressure change C shown in Figure 2. The characteristic diagram shown in FIG. 4 is a waveform diagram showing a 2° correction drive pulse for the electromagnetic pulp on the deceleration side or speed increase side shown in FIG. 2. 1... constant speed traveling device, 2... deceleration side electromagnetic pulp/
ENT), speed increasing side electromagnetic pulp (VAC), 4...
Bellows...Intake manifold, 7...Negative pressure pipe, 8
...Engine 9...Pressure sensor. In the figures, the same reference numerals indicate the same or similar parts. Agent Masuo Oiwa Figure 3 Figure 4 Mr. Commissioner of the Japan Patent Office 1. Description of the case Japanese Patent Application No. 58-128143 2, Name of the invention Constant speed traveling device for automobiles 3, Detailed description of the invention in the specification to be amended by Hitoshi Katayama, representative of Tomari, within Mitsubishi Electric Corporation. Description field. 6. Details of the amendment (1) "Atmospheric pressure" on page 4, line 17 of the specification is corrected to "differential pressure." (2) Same page 6] Correct line 5, ``The following equation can be obtained'' to ``Obtained, that is, the following equation.''

Claims (1)

[Claims] Constant-speed driving for an automobile, comprising a bellows that responds to the differential pressure between internal pressure and atmospheric pressure as a driving source for opening and closing a throttle valve, and a control section that controls the amount of movement of the bellows to adjust the opening degree of the throttle valve. The apparatus includes a pressure sensor that detects the driving negative pressure of the bellows, and the control unit corrects the fluctuation of the bellows key due to the fluctuation of the bellows driving negative pressure by correcting the bellows driving time based on the detected value of the pressure sensor. A constant speed traveling device for an automobile, characterized in that the bellows grip is completely constant.