JPS5854258B2 - Air introduction device during deceleration of internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air introduction device during deceleration of an internal combustion engine, and in particular, to the operating characteristics of a plurality of negative pressure valves for deceleration using one valve device, that is, to temporarily introduce air during sudden deceleration. This invention relates to an air introduction device during deceleration, which has a function to continuously introduce air during deceleration.

When an internal combustion engine decelerates, for example, when the throttle valve is suddenly closed from a high rotational state, the negative pressure in the intake passage downstream of the throttle valve increases rapidly due to the pumping action of the piston, which causes damage to the intake passage wall, etc. The fuel adhering to the engine vaporizes all at once, supplying a temporarily uncombustible overly rich mixture to the combustion chamber, which then ignites and explodes in the exhaust pipe, causing a so-called afterfire problem. .

In addition, if the throttle valve is held at the fully closed idle opening for a long period of time, such as during long-term deceleration, the intake passage downstream of the throttle valve will have an extremely high negative pressure for a long period of time, and the piston sliding surface will A problem arises in that excessive oil is sucked into the combustion chamber (so-called oil overflow), increasing oil consumption.

Conventionally, to solve the above two problems, for example, an anti-after (verge) valve was used to temporarily introduce air during sudden deceleration to solve the problem of afterfire, and an anti-after (verge) valve was used to temporarily introduce air during deceleration to solve the problem of large oil consumption. A separate deceleration countermeasure device such as a BCDD device or throttle opener device that introduces air during deceleration is installed to prevent negative pressure in the intake passage downstream of the throttle valve from suddenly increasing or exceeding a predetermined value. In this case, by bypassing the throttle valve and supplying air into the intake passage downstream of the throttle valve, the negative pressure in the passage is suppressed from rapidly increasing or from exceeding a predetermined value. It solved two problems.

This has complicated the engine layout and increased cost and weight.

In addition, since each air introduction device during deceleration is connected to the intake system with a rubber hose, etc., there is a high incidence of accidents such as hose damage, hose disconnection, and air leakage from the joint with the hose, and inspection and maintenance are troublesome. Ta.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of afterfire and large oil consumption that occur during engine deceleration with a single valve device, thereby simplifying an air introduction device during deceleration.

This will be explained below with reference to the drawings.

FIG. 1 is a system diagram showing an air introduction device during deceleration of the present invention, in which 1 is a gamma cleaner, 2 is an intake passage, 3 is a carburetor, 4 is a carburetor throttle valve, and 5 is an air introduction device during deceleration. main body,
6 is an intake pipe, and 7 is an exhaust pipe.

The deceleration air introduction device main body 5 includes a bypass atmospheric side passage 8 that opens to the intake passage 2 upstream of the throttle valve 4, a bypass negative pressure side passage 9 that opens to the intake pipe 6 downstream of the throttle valve 4, and a bypass negative pressure side passage. The deceleration air introduction device main body 5 is made of metal or plastic, and is connected to the suction negative pressure signal passage 10 that opens into the intake pipe 6 downstream of the opening of the intake pipe 9.
When the negative pressure in the intake pipe 6 downstream of the throttle valve 4, which is introduced through the throttle valve 0, rapidly exceeds the set value at a speed higher than a predetermined value or continuously exceeds the set value, the bypass atmospheric side passage 8 and the bypass negative pressure side passage are closed. In communication, the air is supplied to the intake pipe 6 downstream of the throttle valve 4, bypassing the throttle valve 4.

FIG. 2 is a detailed view showing the main body 5 of the air introduction device during deceleration, in which 11 is an atmospheric inlet to which the end of the bypass atmospheric side passage 8 is connected, and 12 is the atmospheric inlet to which the end of the bypass negative pressure side passage 9 is connected. The air outlet 13 is an air passage through which the air connects the air inlet 11 and the air outlet 12.

The atmospheric passage 13 includes a disc-shaped valve 14 that blocks the atmospheric air passing through the atmospheric passage 13 and controls the flow rate of the atmospheric air.
is set up.

The valve 14 is disposed in a valve chamber 15 formed by enlarging a portion of the inner diameter of the atmospheric passage 13, at right angles to the atmospheric passage 13, and the valve chamber 15 is in contact with the upper surface of the valve 14. A valve is constructed between the valve seat 16 attached to the earthen wall.

The valve seat 16 is made of rubber or the like, and thus absorbs noise during valve operation.

Further, this valve 14 is always subjected to a predetermined force pressed against the valve seat 16 by a spring 17 housed in a valve chamber 15 which is sandwiched between the lower surface of the valve 14 and the lower wall surface of the valve chamber 15. Normally, it is in contact with the valve seat 16 and is in a so-called closed state, blocking the atmospheric passage 13.

The valve 14 is moved away from the valve seat 16 and moved downward within the valve chamber 15 under the force of overcoming the spring 17 in a predetermined case (to be described later) when the negative pressure in the intake pipe 6 downstream of the throttle valve 4 is negative. Then open the valve.

At this time, the flow rate of the atmospheric air flowing through the valve 14 increases in proportion to the descending distance of the valve 14.

The spring 17 is prevented from coming off by a pawl 14a formed by bending the end of the valve 14 downward, thereby improving the operating accuracy of the valve 14.

Further, the valve chamber 15 is provided with a valve 14 located below the valve 14 to prevent the valve 14 from dropping below a predetermined level.
A stopper 18 is provided to regulate the lift amount of the valve 14, that is, the flow rate of atmospheric air flowing through the valve 14.

On the other hand, 19 is a first negative pressure chamber, and 20 is a second negative pressure chamber.

The first negative pressure chamber 19 and the second negative pressure chamber 20 are connected to the diaphragm 2
1, and communicate through a hole with a predetermined minute cross-sectional area passing through a diaphragm 21 or an orifice 22 formed of sintered metal or the like.

The volume of the first negative pressure chamber 19 is set to a predetermined value larger than the volume of the second negative pressure chamber 20.

The second negative pressure chamber 20 also includes a negative pressure passage 24 connected to the suction negative pressure signal passage 10 via a negative pressure signal passage nipple 23.
is open, and the second negative pressure chamber 20 is opened through this passage 24.
The negative pressure in the intake pipe 6 downstream of the throttle valve 4 is directly introduced.

A rod 25 is crimped and engaged with the center of the diaphragm 21 via plays 1-26 and 27,
The rod 25 is a wall portion 28 forming the lower surface of the second negative pressure chamber 20.
The diaphragm 21, which is guided by a guide 29 attached to the
It moves up and down depending on the pressure difference between diaphragm 2 and
When the pressure difference is zero, the end of the rod 25 interlocked with the diaphragm 21 is held in place by the spring 30 held between the lower surface of the valve 14 and the lower surface of the second negative pressure chamber 20 when the valve 14 is closed. , is set so as to be in just contact with a cushioning material 31 such as rubber or synthetic resin for cushioning the impact of the rod 25 fixed to the center of the upper surface of the valve 14, or to have an appropriate gap.

Next, further explanation will be given including the operation.

During sudden deceleration when the throttle valve 4 is suddenly fully closed, the negative pressure in the intake pipe 6 downstream of the throttle valve 4 rises rapidly due to the pump action of the piston, and the negative pressure in the second negative pressure chamber 20 introducing this negative pressure increases. The pressure also increases rapidly.

On the other hand, since the orifice 22 has a predetermined minute cross-sectional area and the volume of the first negative pressure chamber 19 has a predetermined size, the negative pressure in the first negative pressure chamber 19 is lower than the negative pressure in the second negative pressure chamber 20. It takes a predetermined time proportional to the fluctuating pressure difference to equalize the pressure.

Therefore, during this predetermined time, the negative pressure in the second negative pressure chamber 20 is greater than that in the first negative pressure chamber 19, so the diaphragm 21
As shown in FIG.
The valve 14 is pushed down, for example, by about 2 to 4 degrees at most, from the closed position to open the valve 14.

As a result, the throttle valve 4 is bypassed through the bypass atmosphere side passage 8, the atmosphere passage 13, and the bypass negative pressure side passage 9 into the intake pipe 6 downstream of the throttle valve 4 where the negative pressure is about to rise rapidly. A relatively large flow rate of 300 to 5001/mrnPA degrees is introduced instantaneously, and a sudden rise in negative pressure in the intake pipe 6 downstream of the throttle valve 4 is suppressed.

As a result, the negative pressure in the intake pipe 6 downstream of the throttle valve 4 rises rapidly, and the fuel adhering to the walls of the intake pipe 6 vaporizes at once, temporarily supplying a rich air-fuel mixture to the combustion chamber. It is possible to suppress the afterfire and harmful exhaust emissions that occur due to

Furthermore, when the rod 25 hits the valve 14 through the buffer material 31, the buffer material 31 provides soundproofing and at the same time prevents the ends of the rod 25 from being worn out.

Furthermore, since the stopper 18 prevents the valve 14 from lowering beyond a predetermined level, even in the unlikely event that the spring 17 is damaged or the rod 25 and guide 29 are stuck together, there is an excessive amount of fluid in the intake pipe 6 downstream of the throttle valve 4. This prevents a large amount of atmospheric air from being introduced through the valve 14, and it is possible to prevent a situation in which an excessively lean air-fuel mixture is supplied to the combustion chamber and the engine becomes inoperable.

When a predetermined period of time, for example, 5 seconds or more has passed after the throttle valve 4 is fully closed, the negative pressure in the first negative pressure chamber 19 becomes equal to the negative pressure in the second negative pressure chamber 20, and the diaphragm 21 is moved by the force of the spring 30. Move upward to the desired position.

At this time, the throttle valve 4 is still fully closed or close to fully closed, and the engine is in a state of deceleration for a long time, so that the negative pressure in the intake pipe 6 downstream of the throttle valve 4 is caused by the elastic force of the spring 17. a predetermined setting value determined by, e.g. -5701n7I
LHg, or above, the pressure in the intake passage 2 upstream of the throttle valve 4 introduced into the atmospheric passage 13 and the throttle valve 4
Due to the pressure difference between the pressure in the downstream intake pipe 6, the valve 14
receives a downward force that overcomes the spring 17, and moves away from the rod 25, which moves upward in conjunction with the diaphragm 21, and maintains the open state as before, as shown in FIG.

At that time, the valve 14 is set at a maximum of 0.8 to 2, for example, from the closed state.
．． 0 mm below, and the larger the differential pressure is, the greater the force received is at the lower position. Therefore, the flow rate of the atmosphere introduced into the intake pipe 6 downstream of the throttle valve 4 via the valve 14 is also The larger the differential pressure is, the more the throttle valve 4
Since the pressure in the upstream intake passage 2 is always around atmospheric pressure, the greater the negative pressure in the intake pipe 6 downstream of the throttle valve 4, the greater the pressure (
For example, the maximum value is 200 to 300 l/mm>, and as a result, the negative pressure downstream of the throttle valve 4 is always suppressed to a predetermined value or less.

This prevents the occurrence of a situation where extremely high negative pressure continues for a long time, causing excessive oil to be sucked up and consumed in the cylinder, resulting in increased oil consumption.

On the other hand, if the throttle valve 4 is opened again after a predetermined period of time has passed after the throttle valve 4 was suddenly closed, or if the slow deceleration ends, the negative pressure in the intake pipe 6 downstream of the throttle valve 4 will be reduced to a predetermined level. Since it is smaller than the set value, spring 1
7 in conjunction with the diaphragm 21 and rod 25, the valve 14 is pushed up to a position where it contacts the valve seat 16, and the valve 14 is closed.

As explained above, the present invention uses a single deceleration air introduction device to perform the functions of two deceleration air introduction devices that were conventionally required in order to deal with problems that occur during sudden deceleration and long-term deceleration. , the equipment can be simplified.

Therefore, the equipment piping assembly requires fewer pipes and brackets than in the past, so it is less expensive, the weight is reduced, and the fuel efficiency of the engine is improved.

Furthermore, since the engine layout is simplified, a layout with excellent durability, reliability, and ease of assembly and maintenance is possible, and the marketability of the engine can be improved.

Note that the present invention has similar effects even when applied to a fuel injection engine.

Additionally, if used in conjunction with a fuel cut device during deceleration, it is possible to further improve fuel efficiency and exhaust gas countermeasures during deceleration.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing the deceleration air introduction device of the present invention, Fig. 2 is a detailed sectional view showing the main body of the deceleration air introduction device in the device of Fig. 1, and Fig. 3 is the deceleration air introduction device during sudden deceleration. FIG. 4 is a cross-sectional view showing the operation of the air introduction device main body during deceleration during long-term deceleration. 2... Intake passage, 4... Throttle valve, 5...
... Air introduction device during deceleration, 6 ... Intake pipe, 8 ... Bypass atmosphere side passage, 9 ...
...Bypass negative pressure side passage, 13...Atmospheric passage,
14... Valve, 15... Valve chamber, 17
... Spring, 19 ... First negative pressure chamber, 20 ... Second negative pressure chamber, 21 ... Diaphragm, 22 ... Orifice.

Claims (1)

[Scope of Claims] 1. A valve chamber is formed in a part of a passage that bypasses a throttle valve installed in an engine intake passage, and a plate-shaped valve body that opens and closes a valve port is provided in the valve chamber, and a valve body is closed. a first negative pressure chamber that introduces negative pressure in the intake passage downstream of the throttle valve; and a second negative pressure chamber that is separated from the first negative pressure chamber via a diaphragm. a chamber, an orifice communicating the first negative pressure chamber and the second negative pressure chamber, and a rod connected to the diaphragm so as to transmit movement of the diaphragm only in the valve opening direction of the valve body,
When the negative pressure in the intake passage downstream of the throttle valve increases, the valve element opens via a rod fixed to a diaphragm that responds to the differential pressure between the first negative pressure chamber and the second negative pressure chamber, and An internal combustion engine configured such that when the negative pressure above a predetermined value continues to act, the valve body opens in direct response to the pressure difference between the negative pressure and the pressure in the bypass passage upstream of the throttle valve. Air introduction device during deceleration. 2. The air introduction device during deceleration of an internal combustion engine according to claim 1, wherein the elastic force of the spring is selected such that the valve body opens the valve port when the pressure difference is greater than or equal to a predetermined value. 3. The internal combustion engine according to claim 1 or 2, wherein the orifice is configured to move the diaphragm when the negative pressure in the intake passage downstream of the throttle valve changes at a predetermined speed or more. Air introduction device during deceleration.