JPH0433408Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an internal combustion engine equipped with an exhaust gas recirculation device, and particularly to an intake pipe that prevents combustion products (deposits) from adhering to the exhaust gas inlet. It is.

Conventional technology In a normal engine, when the piston reciprocates inside the cylinder, the piston link acts as a kind of pump, so unburned hydrocarbons (HC) enter the engine crankcase through the gap between the piston ring and the cylinder wall. . This unburned HC (generally referred to as blow-by gas) pollutes the atmosphere if released into the atmosphere, so it is normally led to the cylinder head of the engine, and from the cylinder head it is introduced into the intake manifold where it is mixed with intake air. This device is generally called a PCV (positive crankcase ventilation) device.

On the other hand, the engine recirculates a portion of the exhaust gas to the intake system to purify nitrogen oxides (NO _x ) in the exhaust gas. In such exhaust gas recirculation (EGR) devices, as mentioned above, in those that introduce oil vapor or blow-by gas from the crankcase or cylinder head into the intake pipe, the oil vapor or the like is transferred to the outlet of the EGR pipe. (EGR gas inlet of the intake pipe), and when the EGR gas comes into contact with the attached oil, the temperature of the EGR gas decreases, and combustion products (digipots) such as carbon in the EGR gas may accumulate. This means that
This can occur not only in engines equipped with a PCV device, but also in engines equipped with a supercharger (turbocharger).

In order to reduce the accumulation of such digipots, the outlet end of the EGR pipe is made to protrude into the intake pipe (Utility Model Application No. 56-88933, Utility Model Application No. 58-116748).
(No. 58-65922), a guide that guides blow-by gas to the downstream side of the EGR pipe outlet end, where the EGR gas inlet and PCV passage opening are arranged symmetrically with respect to the throttle valve axis (Japanese Patent Application Laid-open No. 1983-65922). (Utility Model Application No. 56-88934), or one with a PCV pipe protruding into the intake pipe (Utility Model Application No. 58-88934).
33713) etc. have been proposed.

Problems to be Solved by the Invention This invention has a simple structure for engines equipped with an exhaust gas recirculation (EGR) device, and is designed to prevent oil vapor, etc. flowing from upstream from flowing into the EGR gas inlet. The purpose of the present invention is to provide an internal shape of the intake pipe that can prevent deposits from accumulating and secure the required amount of EGR.

Means for Solving the Problems According to the present invention, in an internal combustion engine equipped with an exhaust gas recirculation device that introduces a part of exhaust gas into an intake pipe from a recirculation gas inlet, On the inner wall of the intake pipe near the upstream side, a rib that prevents oil from flowing into the gas inlet extends in a substantially V-shape along the inner wall of the intake pipe, and the tip of the substantially V-shape extends along the upstream side of the intake pipe. There is provided an intake pipe characterized in that the intake pipe is shaped so as to face the gas injection port, and is formed so as to cover the wall surface area of the gas inlet when viewed from the upstream side. It is desirable that the included angle of the V-shape is 30° to 90°. Preferably, the rib has a height and width of 4 mm to 5 mm, and a cross-sectional area of the rib is within 5% of the cross-sectional area of the intake pipe.

Embodiments This invention will be described below based on drawings showing embodiments. First, in FIG. 4, 1 is the engine body, 2 is an intake pipe (intake manifold), and 3 is an exhaust pipe. The intake pipe 2 and the exhaust pipe 3 communicate with each other via an EGR pipe 4 and an EGR valve 5.
The EGR valve 5 opens and closes a valve port (inflow port) 5c communicating with the intake pipe 2 by a valve element 5b actuated by the height of the engine intake negative pressure and a spring 5a. Then, EGR gas is introduced into the intake pipe 2 from the EGR gas inlet 10. On the upstream side of the EGR gas inlet 10, the inside of the intake pipe 2 communicates with the inside of the cylinder head cover 6 through a PCV pipe 7. 9 is an air cleaner connected to intake pipe 2 by hose 8.
is connected to.

Figure 1 is a view of the vicinity of the EGR gas inlet of the intake pipe of the invention as seen from above when mounted on a vehicle, Figure 2 is a cross-sectional view taken along the line - in Figure 1, and Figure 3 is a view of the area around the EGR gas inlet of the invented intake pipe. It is an enlarged view of the part shown by the code|symbol. An EGR valve 5 is attached to the intake pipe (intake manifold) 2 via a gasket 11.
The EGR gas outlet part 12 of the EGR valve 5 is connected to the intake pipe 2
It is slightly sunken into the upper side of the
The EGR gas inlet 10 opens into the intake pipe 2 from the upper side where the flow of oil within the intake pipe 2 is least. Upstream of the EGR gas inlet 10, on the inner wall (upper wall) of the intake pipe 2, there is a rib or dam 13 extending in a V-shape as shown in the figure.
They are formed with more distance between them. The V-shaped tip 13a of this rib 13 faces the upstream side of the intake pipe 2, and the EGR gas inlet 10
It is located on a straight line extending upstream from. Further, both ends 13b and 13c of the V-shape of the rib 13
extend to the vicinity of both sides of the EGR gas inlet 10 and to a position lower than the EGR gas inlet 10 (in FIG. 2, a position to the right of the EGR gas inlet 10). In particular, in FIG. 2, the distal end 13b is located at a much lower position than the EGR gas inlet 10. In short, the ribs 13 completely cover the wall area of the gas inlet 10 when viewed from the upstream side. Furthermore, both end portions 13b and 13c extend to a position immediately in front of the EGR gas inlet 10 with respect to the flow direction P of intake air.

It is appropriate for the V-shaped rib or weir 13 to have an included angle α of 30° to 90° as shown in FIG. 1, and a height h and a width w as shown in FIG. It is appropriate that both of them are about 4 mm to 5 mm, and that the cross-sectional area of the rib 13 is within 5% of the cross-sectional area of the flow path of the intake pipe 2. Moreover, the cross section of the V-shaped rib 13 is
As shown in FIG. 3, on the outside of the V-shape, that is, on the upstream side of the intake pipe 2, the radius of curvature of the corners a at the top and bottom is 1 mm or less, and the oil flowing from the upstream side of the intake pipe 2 is By making it difficult to cross inside the V-shaped rib 13, and by making the radius of curvature of the corners b at the top and bottom of the rib 13 at least 3 mm on the downstream side, the area inside the V-shape of the rib 13 becomes a pool and enters the intake air. This is to prevent the dusty oil or water contained therein from accumulating.

In Fig. 1, fresh air (air) flowing in the direction of arrow P in the intake pipe 2 is connected to the PCV pipe 7 (Fig. 4).
These include PCV gas introduced from the engine, or oil components contained in the supercharged intake air from a turbocharger (not shown). Since this oil component is heavier than air, it tends to flow along the inner wall of the intake pipe 2. Since the EGR gas inlet 10 is provided above the intake pipe 2, it is in a position where it is relatively difficult for oil to flow in. However, if you approach the EGR gas inlet 10, the oil component will be absorbed by the V-shaped rib 13 as indicated by the arrow Q. As shown, the gas is separated from both sides of the EGR gas inlet 10 and flows downstream thereof. On the other hand, when the EGR valve 5 is open, the EGR inlet 10
EGR gas is introduced into the intake pipe 2. Intake pipe 2
After being introduced into the system, the EGR gas mixes with fresh air, and after being sufficiently mixed, it joins the oil components mentioned above. Therefore, deposits will not accumulate mainly near the EGR injection port 10.

Effects of the invention According to the invention, in an internal combustion engine equipped with an exhaust gas recirculation (EGR) device, even if oil components are included in the PCV gas or supercharged intake air of the turbocharger, the EGR gas can be used as fresh air. Since it is mixed with these oil components, etc., deposits containing carbon particles and impurities are not generated or accumulated in the intake pipe, and therefore, a sufficient amount of EGR can be secured. Further, since the V-shaped rib 13 in the present invention has almost no effect on the flow of fresh air within the intake pipe 2, there is no risk of reducing intake efficiency.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the present invention, and is a top view of the vicinity of the EGR gas inlet of the intake pipe of an internal combustion engine, Fig. 2 is a sectional view taken along the line - in Fig. 1, and Fig. The figure is an enlarged view of the portion indicated by the reference numeral in FIG. 2, and FIG. 4 is a schematic diagram showing the entire internal combustion engine equipped with an EGR device. 2...Intake pipe (intake manifold), 10...
EGR gas inlet, 13...V-shaped rib.

Claims (1)

[Claims for Utility Model Registration] 1. In an internal combustion engine equipped with an exhaust gas recirculation device that introduces a portion of exhaust gas from the recirculation gas inlet 10 into the intake pipe 2, near the upstream of the recirculation gas inlet 10. A rib 13 for preventing oil from flowing into the gas inlet 10 is provided on the inner wall of the intake pipe 2 and extends in a substantially V shape along the inner wall of the intake pipe 2.
An intake pipe characterized in that the intake pipe 3a is shaped such that it faces upstream of the intake pipe 2, and is formed so as to cover the wall surface area of the gas inlet 10 when viewed from the upstream side. 2. The intake pipe according to claim 1, wherein the included angle of the V-shape is 30° to 90°. 3. The intake pipe according to claim 1 or 2, wherein the rib 13 has a height and radius of 4 mm to 5 mm, and its cross-sectional area is 5% or less of the cross-sectional area of the intake pipe 5. .