JPH0130604Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a high-pressure valve opening control device that has an altitude compensation function and prevents the air-fuel ratio from becoming excessively rich at high altitudes.

[Conventional technology and its problems]

2. Description of the Related Art Conventionally, there has been known a control device for a check valve that uses a diaphragm as an actuator, communicates a diaphragm chamber of the diaphragm with an intake pipe, and opens the check valve as negative pressure in the intake pipe increases. However, the operating characteristics of the diaphragm of the control device for the Cheyoke valve are the same in both flat and highlands. For this reason, at high altitudes, the negative pressure in the engine intake pipe decreases, so at high altitudes, the reduction in the negative pressure in the intake pipes causes the valve opening to become smaller than the required opening, causing the air-fuel ratio to become excessively rich.
There was a risk of deterioration of exhaust emissions and deterioration of driving performance.

The purpose of this invention is to improve drivability by preventing the air-fuel ratio from becoming too rich at high altitudes and from becoming too lean at or near full load. An object of the present invention is to provide a valve opening control device.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a diaphragm device in which a diaphragm chamber is defined by a diaphragm, a diaphragm lever having one end connected to a diaphragm valve and the other end fixed to the diaphragm.
The diaphragm chamber includes an elastic body built in the diaphragm chamber that urges the throttle lever in the direction of closing the throttle valve, and a communication passage that communicates the diaphragm chamber with the downstream side of the throttle valve in the intake passage. By transmitting to the diaphragm chamber through
A check valve opening control device for controlling the opening of a check valve, wherein a check valve that opens in response to negative pressure in the intake passage is provided in the communication passage, and a check valve that opens in response to negative pressure in the intake passage is provided in the communication passage, and a check valve that opens in response to negative pressure in the intake passage is provided on a side of the intake passage from the check valve. A control valve that is opened to the atmosphere only when driving on flat ground is connected to the intake passage side of the check valve, and when the negative pressure in the intake passage decreases, the check valve of the communication passage is connected to the intake passage side of the check valve. It is characterized by connecting a valve device that introduces the atmosphere to the diaphragm chamber side from the valve.

[Effect]

According to the above configuration, when traveling at a constant speed on flat ground, the inside of the intake passage becomes high negative pressure, so the check valve opens and the negative pressure inside the intake passage is passed through the communication passage to the diaphragm of the diaphragm device. transmitted to the chamber. At the same time, the atmosphere is introduced into the diaphragm chamber of the valve device through the control valve, and the valve device is operated to introduce the atmosphere into the communication passage. However, because the negative pressure in the intake passage is large, even if the atmosphere is introduced into the communication passage,
The diaphragm moves against the biasing force of the elastic body,
The movement is transmitted to the check valve via the check lever, and the opening degree of the check valve is set to a predetermined value.

Furthermore, when accelerating on flat ground, the negative pressure in the intake passage decreases, so the check valve closes. However, because the atmosphere is introduced into the communication path through the valve device, the negative pressure in the diaphragm chamber of the diaphragm device gradually decreases, and the diaphragm of the diaphragm device moves in the opposite direction to the above-mentioned direction due to the urging force of the elastic body. direction to quickly close the check valve.

Furthermore, when traveling at a constant speed on high ground, the inside of the intake passage becomes high negative pressure, so the negative pressure is transmitted to the diaphragm chamber of the diaphragm device in the same way as in the case on flat ground. However, in this case, since the control valve is closed, the negative pressure in the intake passage acts on the diaphragm chamber of the valve device, causing the valve device to close. That is, since atmospheric air is not introduced through the valve device, a large negative pressure acts on the diaphragm chamber of the diaphragm device. For this reason, the opening degree of the choke valve becomes larger than in the case of flat ground, and the air-fuel ratio is prevented from becoming too rich.

In addition, when accelerating at high altitudes, the negative pressure in the intake passage decreases and the check valve closes, so the negative pressure in the diaphragm chamber of the diaphragm device is held until the predetermined throttle opening, and the air-fuel ratio suddenly increases. is prevented from becoming darker. In addition, when the throttle opening exceeds a predetermined degree, the negative pressure in the intake passage further decreases, so the negative pressure in the diaphragm chamber of the valve device decreases and the valve device opens, allowing atmospheric air to enter the diaphragm device through the valve device. It is introduced into the diaphragm chamber, and the opening degree of the choke valve becomes smaller.

〔Example〕

Embodiments of the present invention will be described based on the drawings. In the figure, a protrusion 12A is formed on a valve shaft 12 of a chiyok valve 10 provided in an intake passage 1 of a carburetor, and the protrusion 12A is connected to one end 24A of a chiyok lever 24. The other end of the choke lever 24 is fixed to the diaphragm 21 of the diaphragm device 2.

This diaphragm device 2 includes a diaphragm 21
A diaphragm chamber 23 is defined by the diaphragm chamber 23. A spring 22 is built in the diaphragm chamber 23, and the spring 22 rotates the diaphragm lever 24 to the left, that is, to rotate the diaphragm valve 10 in the closing direction. 24 is energized.

Further, on the downstream side of the throttle valve 14 in the intake passage 1, a negative pressure port a for taking out intake pipe negative pressure is communicated with the inlet side of the check valve 4 via communication passages 71 and 72. The outlet side of 4 is the communication path 7
3. The orifice 3 communicates with port b of the diaphragm device 2 via a communication path 74.

Furthermore, a communication passage 75 is connected to a confluence point 80 of the communication passages 71 and 72, a crest 81 is provided on this communication passage 75, and an end of the communication passage 75 communicates with port c of the control valve 5. ing.

The control valve 5 is composed of a bellows 51, a spring 52 that compresses the bellows 51 upward in the diagram, a port d communicating with the atmosphere, and a filter 53.
On flat ground, the bellows 51 is contracted by the compression force of the spring 52, and the port d is in an open state.
At high altitudes, the atmospheric pressure decreases, so the bellows 51 expands against the compression force of the spring 52.
Port d is blocked.

Also, a check valve 4 is provided between the communication passage 73 and the communication passage 75.
A valve device 6 is arranged in parallel. The valve device 6 has a diaphragm chamber 63 defined by a diaphragm 61 and a chamber 66 communicating with the atmosphere through a filter 65 and a port h.
A valve body 64 for opening and closing a port g provided in a chamber 66 is fixed to the valve body 1 .

Further, a spring 62 is attached to the diaphragm 61, and the spring 62 urges the diaphragm 61 downward in the figure.

The orifice 3 is used to slowly open the choke valve when starting the engine, and the operating pressures of the diaphragm device 2 and the valve device 6 are set so that the valve device 6 has a lower negative pressure.

In the above configuration, on a flat ground, the bellows 51 of the control valve 5 is contracted and the port d is open, and the port e of the valve device 6 is connected to the port e of the valve device 6 through the filter 53 at the atmosphere opening port, the port d, the port c, and the communication passages 75 and 77. , the atmosphere is introduced into the diaphragm chamber 63, the diaphragm 61 is pushed downward in the figure by the biasing force of the spring 62, the valve body 64 is lowered as shown in the figure, the port g is opened, and the filter 65 of the atmosphere opening port is pushed downward. , ports h, g, and f, the communication path 76 is opened to the atmosphere.

On the other hand, the negative pressure generated in port a is
72, the check valve 4, the communication passage 73, the orifice 3, and the communication passage 74, and are introduced into the diaphragm chamber 23 from port b.

Here, when a high negative pressure is generated at port a, even if the atmosphere is introduced from the communication path 76 through the ridge 82, the diaphragm 2 does not enter the diaphragm chamber 23.
Sufficient negative pressure is introduced to subtract 1. When the negative pressure in port a decreases, the check valve 4 closes and blocks communication between the communication passages 72 and 73, so that the negative pressure in the diaphragm chamber 23 is maintained, but atmospheric air is introduced from the communication passage 76. The negative pressure in the diaphragm chamber 23 decreases, and the choke valve 10 gradually closes, enriching the air-fuel ratio and preventing deterioration of drivability.

At high altitudes, the bellows 51 of the control valve 5 extends and the port d is closed, so that the negative pressure of the port a is applied to the diaphragm chamber 63 of the valve device 6.
75 and 77, and when the negative pressure is above a certain level, the diaphragm 61 is pulled upward in the figure against the biasing force of the spring 62, and the valve element 64 closes the port g by closing the check valve 4. is in a closed state, the negative pressure held in the diaphragm chamber 23 does not drop, and the choke valve 10 is in an open state, so that the air-fuel ratio does not become richer than necessary. When the throttle valve 14 is fully open (at full load) or close to it, and the negative pressure at port a decreases significantly and becomes below a certain level of negative pressure, the diaphragm 61 will move downward in the figure due to the biasing force of the spring 62. When pressed, the valve body 64 opens the port g, and the diaphragm chamber 23
Atmospheric air is introduced into the engine, the choke valve 10 is closed, the air-fuel ratio is enriched, and deterioration of drivability is prevented.

[Effect of idea]

According to the present invention, it is possible to prevent the air-fuel ratio from becoming unnecessarily rich at high altitudes and from becoming too lean at or near full load, thereby improving drivability.

[Brief explanation of the drawing]

The drawing is a configuration diagram showing an embodiment of a chiyork valve opening degree control device according to the present invention. 1...Intake passage, 2...Diaphragm device, 3
... Orifice, 4 ... Check valve, 5 ... Control valve,
6...Valve device, 10...Chiyoke valve.

Claims (1)

[Scope of utility model registration request] A diaphragm device in which a diaphragm chamber is defined by a diaphragm, a Chiyoke lever having one end connected to a Chiyoke valve and the other end fixed to the diaphragm, and an elastic body built in the diaphragm chamber and biasing the Chiyoke lever in the Chiyoke valve closing direction. and a communication passage that communicates the diaphragm chamber with the downstream side of the throttle valve in the intake passage, and controls the opening degree of the choke valve by transmitting the negative pressure in the intake passage to the diaphragm chamber via the communication passage. In the check valve opening control device, a check valve that opens in response to negative pressure in the intake passage is provided in the communication passage, and a check valve that opens in response to negative pressure in the intake passage is provided in the communication passage on the intake passage side from the check valve. A control valve that opens is connected to the intake passage side of the check valve in the same way as the control valve, and when the negative pressure in the intake passage decreases, atmospheric air is connected to the diaphragm chamber side of the communication passage from the check valve. What is claimed is: 1. A chiyoke valve opening control device, characterized in that it is connected to a valve device that introduces.