JP2001280515A - Egr valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the pressure loss of an EGR valve. SOLUTION: This EGR valve 1 for an engine has an EGR passage 4 which leads EGR gas to an exhaust passage from an intake passage, and an poppet valve element 10 opening and closing the EGR passage 4. The valve element 10 has a poppet like guide part 13 projecting against a flow of the EGR gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an EGR valve provided in an engine.

[0002]

2. Description of the Related Art An engine that recirculates EGR gas from an exhaust passage to an intake passage is provided with an EGR valve that adjusts the amount of EGR gas in accordance with operating conditions.
9, No. 9).

A conventional EGR valve has an umbrella valve-shaped valve element that is seated on a seat portion, and the EGR passage is opened by lifting the valve element from the seat portion.

[0004]

In a diesel engine or the like having a small pressure difference between the intake passage and the exhaust passage, there is a demand that the pressure loss of the EGR valve be reduced as much as possible in order to recirculate a large amount of EGR gas. .

However, the conventional EGR valve has a structure in which the end surface of the umbrella valve-shaped valve element is opposed to the flow of the EGR gas. There was a problem that pressure loss could not be reduced.

The present invention has been made in view of the above problems, and has as its object to reduce the pressure loss of an EGR valve.

[0007]

According to a first aspect of the present invention, there is provided an EGR passage for guiding EGR gas from an intake passage to an exhaust passage;
The present invention is applied to an EGR valve of an engine including an umbrella valve-shaped valve element that opens and closes an R passage.

[0008] An umbrella-shaped guide portion protruding from the valve body in opposition to the flow of the EGR gas is provided.

According to a second aspect of the present invention, an EGR passage upstream of the valve body is provided with a pipe expanding portion whose cross-sectional area gradually increases toward the valve body.

[0010] In a third aspect based on the first aspect, a spiral guide portion spirally protruding from the inner wall surface of the expanded portion is formed.

[0011]

According to the first aspect of the present invention, the EGR
Since the gas hits the umbrella-shaped guide portion and spreads around the valve body, it is possible to suppress the occurrence of flow stagnation on the upstream side of the valve body and reduce the pressure loss of the EGR valve. As a result, even in a diesel engine or the like having a small pressure difference between the intake passage and the exhaust passage, a large amount of EGR gas can be recirculated, and exhaust emission can be improved.

In the second aspect of the present invention, since the EGR gas flows around the valve element along the expanded portion, it is possible to suppress the occurrence of stagnation on the upstream side of the valve element and to reduce the pressure loss of the EGR valve. Can be reduced.

In the third aspect of the invention, the EGR gas flows so as to spread around the valve body along the expanded portion, and flows while turning along each spiral guide portion. The occurrence of stagnation can be suppressed, and the pressure loss of the EGR valve can be reduced.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the EGR valve 1
A valve housing 2 that defines an R passage 4 is provided, and a valve body 10 that opens and closes the EGR passage 4 is housed in the valve housing 2. When the EGR valve 1 is opened, inactive EGR gas flows from an exhaust passage (not shown) of the engine into the EGR passage 4.
To return to the intake passage. As a result, in the engine, the oxygen concentration in the cylinder is reduced, and the combustion temperature of the fuel is lowered, so that generation of NOx can be suppressed.

The valve body 10 has a rod-shaped stem portion 11 and an umbrella valve-shaped umbrella portion 12. The umbrella portion 12 is seated on the seat portion 3 to close the EGR passage 4, and the stem portion 11 is not shown. The EGR amount is increased / decreased in accordance with the lift amount at which the umbrella portion 12 is separated from the seat portion 3 by being connected to the actuator.

The gist of the present invention is to provide an umbrella-shaped guide portion 13 protruding from the valve body 10 in opposition to the flow of the EGR gas to reduce the pressure loss of the EGR valve 1.

The umbrella-shaped guide portion 13 of the valve 10 protrudes in an umbrella shape, and its cross section is concentric with the valve 10. That is, the umbrella-shaped guide portion 13 is formed symmetrically with respect to the center line of the valve body 10. The protruding height of the umbrella-shaped guide portion 13 is EGR
It is set arbitrarily according to the shape of the passage 4 and the like.

The operation of the embodiment of the present invention configured as described above will now be described.

Since the EGR gas flowing through the EGR passage 4 strikes the umbrella-shaped guide portion 13 of the valve body 10 and spreads around the umbrella portion 12 as shown by the arrow in the figure, the EGR gas flows upstream of the umbrella portion 12. The stagnation of the flow of the EGR gas can be suppressed, and the pressure loss of the EGR valve 1 can be reduced. As a result, even in a diesel engine or the like having a small pressure difference between the intake passage and the exhaust passage, a large amount of EGR gas can be recirculated, and exhaust emission can be improved.

Next, another embodiment shown in FIG. 2 will be described. The same components as those in the above-described embodiment are denoted by the same reference numerals.

The EGR valve 1 has an E upstream of the valve body 10.
An upstream housing (20) defining the GR passage (4) is provided, and the upstream housing (20) is formed with a pipe expanding portion (21) whose cross-sectional area gradually increases toward the valve body. The cross-sectional area of the expanded portion 20 increases at a substantially constant rate from the upstream side to the downstream side.

The upstream housing 2 is constructed as described above.
The EGR gas passing through the umbrella section 12 along the expansion section 20
, The stagnation of the flow of the EGR gas on the upstream side of the umbrella portion 12 can be suppressed, and the pressure loss of the EGR valve 1 can be reduced.

Next, another embodiment shown in FIGS. 3 and 4 will be described. The same components as those in the above-described embodiment are denoted by the same reference numerals.

A plurality of spiral guide portions 22 projecting spirally from the inner wall surface of the tube expanding portion 20 are formed. Each spiral guide portion 22 is formed symmetrically with respect to the center line of the EGR passage 4.

In this case, the EGR gas passing through the upstream housing 20 flows along the pipe expanding section 20 around the umbrella section 12 and spreads along the spiral guide sections 22.
, The flow of the EGR gas is prevented from being stagnated upstream of the umbrella portion 12,
The pressure loss of the R valve 1 can be reduced.

It is apparent that the present invention is not limited to the above-described embodiment, and that various changes can be made within the scope of the technical idea.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an EGR valve showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an EGR valve showing another embodiment.

FIG. 3 is a cross-sectional view of an EGR valve showing still another embodiment.

FIG. 4 is a plan view of the valve housing.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 EGR valve 4 EGR passage 10 valve body 12 umbrella section 13 umbrella-shaped guide section 21 expanding section 22 spiral guide section

Claims (3)

[Claims] An EGR valve for an engine, comprising: an EGR passage for guiding EGR gas from an intake passage to an exhaust passage; and an umbrella valve-shaped valve body for opening and closing the EGR passage. An EGR valve comprising an umbrella-shaped guide portion protruding in opposition to the EGR valve. 2. An EGR valve for an engine, comprising: an EGR passage for guiding EGR gas from an intake passage to an exhaust passage; and an umbrella valve-shaped valve body for opening and closing the EGR passage. An EGR valve, characterized in that an EGR valve is provided in the passage with a pipe expanding portion whose cross-sectional area gradually increases toward the valve body. 3. The EGR valve according to claim 1, wherein a spiral guide portion spirally protruding from an inner wall surface of said expanded portion is formed.