JP2998548B2 - Air governor for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an engine, that is, an air governor for an internal combustion engine having an exhaust gas recirculation device.

[0002]

2. Description of the Related Art An exhaust gas recirculation device (hereinafter referred to as an EGR device) is interposed between an intake passage and an exhaust passage of an internal combustion engine, and returns a part of the exhaust gas to the intake passage to burn again. was introduced into the chamber, lowering the maximum combustion temperature is an effective device to achieve low NO _X of the exhaust gas.

FIG. 3 shows a conceptual structure of an intake system in the case where this EGR device is used in combination with a so-called air governor device which controls the rotation of an engine by controlling the amount of intake air. In FIG. 1, an EGR device 3 is attached to an end of an intake manifold 1 connected to a cylinder head of an engine. This EGR
The EGR pipe 3a of the device 3 communicates with an exhaust system or an exhaust manifold (not shown), and introduces a part of the exhaust gas into the intake manifold 1 under predetermined conditions. An air governor 5 is provided between the inlet of the intake manifold 1 and the carburetor 7 to control the flow rate of the air-fuel mixture generated by the carburetor 7. An eccentrically supported governor valve 5a of the air governor 5 includes a rod 5c connected to a governor piston 5b.
And one end of a piston chamber containing the governor piston 5b is open to atmospheric pressure.

In this way, the inlet side pressure and the outlet side pressure act on both surfaces of the governor valve 5a, respectively, and the rod force due to the differential pressure between the inlet side pressure and the atmospheric pressure acts on the both sides to match the load. Rotation control is performed.

[0005]

In the conventional apparatus described above, when the EGR valve 3b of the EGR device 3 is operated to introduce a part of the exhaust gas into the intake manifold 1, the pressure in the intake manifold 1, that is, the pressure in the intake manifold 1, that is, The outlet side pressure of the air governor 5 described above increases, and the pressure difference acting on the governor valve 5a fluctuates. For this reason, the opening degree of the governor valve 5a is not the same as before the operation of the EGR valve 3b, and there is a possibility that an engine rotation control becomes impossible or hunting occurs.

[0006] The present invention has been made in view of these circumstances, and in an internal combustion engine provided with an EGR device, even if the EGR device is operated, the internal combustion engine is provided with an EGR device capable of performing appropriate rotation control. It is an object of the present invention to provide an air governor device for an internal combustion engine.

[0007]

According to the present invention, an air governor is interposed between an intake manifold and a carburetor, and an exhaust gas recirculation device is attached to the intake manifold. In the internal combustion engine, the piston chamber of the air governor and the exhaust gas outlet passage of the exhaust gas recirculation device are configured to communicate with each other via a vacuum pipe. It is preferable to provide a throttle or an orifice in the vacuum pipe.

[0008]

In the above configuration, the air-fuel mixture that has exited the carburetor passes through the air governor and flows into the piston cylinder from the cylinder head. At this time, the air-fuel mixture passes through the air governor, so that the flow rate is controlled and the engine rotation is controlled. Done. During this operation, the EGR device operates to cause exhaust gas to enter the intake manifold and increase the pressure value on the outlet side of the air governor. When the exhaust gas passes through the exhaust gas outlet passage of the EGR device, a negative pressure determined by the flow velocity or the flow rate is generated. Is generated to absorb the pressure fluctuation between the governor valves of the air governor. That is,
Even when the EGR device is operated to put the exhaust governor into the intake manifold, the valve opening of the air governor is maintained at a substantially predetermined value. If the vacuum piping has a restriction,
Even if there is a sudden negative pressure change in the exhaust gas outlet passage of the air governor, a sudden pressure fluctuation in the piston chamber is reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts. In FIG. 1, an EGR device 13 is attached to an intake manifold 11 that communicates with an intake passage of a cylinder head of an engine (not shown). The EGR device 13 communicates with the intake manifold 11 through an exhaust gas outlet passage or EGR pipe 13a provided in the housing 13f, and further connects the exhaust gas inlet passage or EGR pipe 1 to an exhaust manifold (not shown).
3b. EGR pipes 13a, 13
A partition plate 13g defining a valve seat 13e is provided between the housings 13b and 13b. Exhaust gas from the exhaust manifold is supplied to a diaphragm valve 13 provided at a position above the housing 13f.
13d driven by a rod 13h through a rod 13h
Moves upward with respect to the above-mentioned valve seat 13e, flows as shown by the arrow G, and flows into the intake manifold 11. When the valve body 13d is driven downward by the diaphragm valve 13c and pressed against the valve seat 13e as shown in the figure, the passage connecting the EGR pipes 13a and 13b is closed, and no exhaust gas flows.

An air governor 15 is connected to an inlet of the intake manifold 11 on the upstream side of the EGR pipe 13a via a gasket 14, and a carburetor 17 is similarly connected to the air governor 15 via a gasket 16.
Are connected. The carburetor 17 may be a conventional carburetor, for example, as used in the conventional apparatus shown in FIG. 3, and a detailed mechanism for creating a fuel-air mixture is omitted from the illustration. It has a valve or carburetor valve 17a, which is provided in the intake passage.

The cylindrical housing 15h of the air governor 15
There is a governor valve 15a eccentrically and rotatably supported by a pin 15i, and a rod 15d connected to a piston 15c in a piston chamber 15b outside the housing 15h is indicated by the reference numeral 15j on the governor valve 15a. So articulated. Also, the governor valve 15a
Governor cam 15e mounted around the fulcrum of rotation
A governor spring 15f is suspended between the housing and the inner surface of the housing 15h. The back side of the piston 15c in the piston chamber 15b is opened to the atmospheric pressure,
The front side of c communicates with the space on the upstream side of the governor valve 15a of the air governor 15 through the gap of the insertion hole 15g of the rod 15d. Further, the EG of the aforementioned EGR device 13
The R pipe 13 a communicates with the insertion hole 15 g of the air governor 15 via a vacuum pipe 20.

In the above configuration, the intake air is supplied to the carburetor 1
7, the air governor 15 and the intake manifold 11 flow in this order to generate a pressure Pa upstream of the carburetor valve 17a, a pressure Pb between the carburetor valve 17a and the governor valve 15a, and a pressure Pc downstream of the governor valve 15a.

That is, the pressure difference Pb-Pc acts across the governor valve 15a, and the governor valve 15a is eccentric and receives a moment in the closing direction. Further, the pressure difference between the atmospheric pressure and the pressure Pb acts on the piston 15c,
This is also applied as a closing force to the governor valve 15a through the rod 15d. This acts in addition to the above-mentioned moment, but the elastic force of the governor spring 15f also acts in a form that balances these forces and moments.
An appropriate engine speed can be obtained with each load.

Here, when the valve element 13d of the EGR device 13 moves upward and separates from the valve seat 13e, exhaust gas flows in the direction of arrow G and flows into the intake manifold 11. In this state, the amount of intake air flowing past the governor valve 15a is reduced, and the pressure difference between both side surfaces of the governor valve 15a is reduced, so that the moment in the closing direction of the governor valve 15a is reduced (the governor spring 15f).
, The governor valve 15a tends to move in the opening direction. ).

However, at this time, the exhaust gas is EG
The negative pressure generated by flowing through the R pipe 13a is transmitted to the piston chamber 15b via the vacuum pipe 20. As a result, the pressure difference across the piston 15c increases, and the rod 1
The signal is transmitted to the governor valve 15a via 5d. As a result, even if the downstream pressure Pc of the governor valve 15a increases due to the inflow of exhaust gas, the negative pressure due to the flow of exhaust gas increases the pressure difference across the piston 15c, and the opening of the governor valve 15a is properly maintained. Thus, the engine speed control is properly performed without being affected by the operation of the EGR device 13.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, a plurality of vacuum pipes 20 may be provided, and in the above embodiment, the inner diameter cross-sectional area of the vacuum pipe 20 was uniform, but as shown in the modified embodiment of FIG. A throttle 21 may be provided in the pipe 20. In this way, the negative pressure fluctuation in the space on the front side of the piston chamber 15b is reduced, so that the movements of the rod 15d and the governor valve 15a are not abrupt, and hunting of the engine is prevented. The modified embodiment of FIG. 2 has the same configuration as the embodiment of FIG.

[0017]

As described above, according to the present invention,
Even when the EGR device and the air governor are used together, the addition of the vacuum pipe compensates and balances the pressure fluctuations due to the exhaust gas recirculation, so that the air governor operates properly, and the engine speed is adjusted according to the load. It can be controlled appropriately. Further, when a throttle is provided in the vacuum pipe, hunting of the governor valve does not occur even in the case of a sudden negative pressure change, so that a more reliable air governor device can be provided.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a partial cross section of a structure of an air governor device according to a preferred embodiment of the present invention.

FIG. 2 is a conceptual diagram of another embodiment in which the embodiment of FIG. 1 is partially modified.

FIG. 3 is a conceptual diagram of a conventional air governor device.

[Explanation of symbols]

Reference numeral 11: intake manifold, 13: EGR device (exhaust gas recirculation device), 13a: EGR pipe (exhaust gas outlet passage), 15: air governor, 15a: governor valve, 15
b: piston chamber, 17: carburetor, 20: vacuum pipe, 21: throttle.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI F02D 9/10 F02D 9/10 H (58) Field surveyed (Int.Cl. ⁷ , DB name) F02M 25/07 540 F02M 25 / 07 580 F02D 9/02 F02D 9/02 361 F02D 9/10 F02D 9/02 331 WPI (DIALOG)

Claims (2)

(57) [Claims] 1. An internal combustion engine in which an air governor is interposed between an intake manifold and a carburetor and an exhaust gas recirculation device is attached to the intake manifold, wherein a piston chamber of the air governor and the exhaust gas recirculation device are provided. An air governor device for an internal combustion engine, wherein the air governor device communicates with an exhaust gas outlet passage through a vacuum pipe. 2. The air governor device for an internal combustion engine according to claim 1, wherein a throttle is provided in the vacuum pipe.