JPS5821092B2 - Internal combustion engine exhaust port liner device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust port liner device for providing a heat-retaining structure to an exhaust port in a cylinder head.

In an exhaust purification system that maintains the temperature of exhaust gas discharged from a cylinder at a high temperature and oxidizes unburned harmful components in the gas in the exhaust system, the inside of the exhaust port of the cylinder head is A heat insulating structure is provided in which a liner is provided with an appropriate heat insulating gap, thereby preventing a drop in the temperature of the exhaust gas.

This liner is installed with a predetermined gap between it and the inner wall over the entire area of the curved exhaust port, so it is quite difficult to incorporate it into the exhaust port.

Conventionally, therefore, a method has been mainly adopted in which a liner is separately prepared and then used as a core and integrally cast into the cylinder head when the cylinder head is cast.

In this method, in order to support the liner, for example, a protruding edge must be provided on the outer periphery of the liner, and this must be cast and bonded into the head, so heat is transferred to the cylinder head from the bonded area between the liner and the head. In addition to the problem that the heat retention effect is reduced due to the side holes escaping, there is also the disadvantage that the manufacturing of the head becomes complicated and the cost increases, such as removing sand from the part that will become the insulation gap after casting. .

Due to these drawbacks, the liner is divided into multiple pieces,
For example, Japanese Utility Model Application Publication No. 50-8313 has proposed a system in which a split liner is assembled into the exhaust port after the head is cast.

The present invention relates to an improvement of an exhaust port liner device in which such a liner is divided and assembled into an exhaust port, and is particularly characterized by the installation and connection form of the divided liner, and the strength of the assembled liner is improved. The object of the present invention is to obtain a liner device which has a high heat insulating effect and has a small contact area with the head.

For this purpose, the present invention divides a port liner installed throughout the exhaust port of the cylinder head into a plurality of pieces in the flow direction of exhaust gas to form divided liners,
The most upstream liner of the split liner is inserted into the exhaust port from the opening on the exhaust valve side, and the inserted rear end is fixed to the exhaust valve seat, etc., and the downstream liner is inserted into the opening on the other exhaust pipe connection side. The inner end of the inserted liner is inserted into the exhaust port from the top, and the inner end of the inserted liner is fitted so as to overlap inside the end of the upstream liner, and the liner is fixed at the overlapped part by means such as spot welding to connect the upstream liner and the downstream liner. At the same time, the insertion rear end of the downstream liner is slidably supported on the exhaust port outlet side with a predetermined gap between the inner wall of the port and the downstream liner by a ring-shaped collar fitted to its outer periphery. The exhaust port is characterized in that there is a predetermined gap from the inner wall of the exhaust port over the entire area.

The embodiment will be described below with reference to the drawings.
2 is a cylinder head, 2 is an exhaust port, and 3 is a port liner incorporated into the exhaust port 2 according to the present invention.

This port liner 3 is divided into two by an overlapping portion 6 in the flow direction of exhaust gas, and consists of two divided liners: an upstream liner 3a and a downstream liner 3b.

One upstream liner 3a is inserted into the exhaust port 2 from the opening on the exhaust valve side, and its inserted rear end is spot-welded to the exhaust valve seat portion 5 at appropriate locations, for example, at four locations around the circumference. Fix it by.

The other downstream liner 3b is inserted into the exhaust port 2 from the opening on the opposite exhaust pipe connection side, and its insertion inner end is fitted so as to overlap inside the end of the upstream liner 3a. Then, the overlapping parts are fixed and connected by means such as spot welding.

As a result, the upstream liner 3a and the downstream runner 3b are integrally connected in the exhaust port 2, and the downstream liner 3b connected in this way has a ring-shaped collar 7 on its outer periphery at the insertion rear end. and is fixed to the liner 3b by spot welding or the like at three locations on the circumference, for example.

The insertion rear end of the downstream liner 3b is slidably supported with a predetermined gap between the inner wall of the exhaust port 2 and the inner wall of the exhaust port 2 via the collar 7.

The port liner device of the present invention having such a configuration ζAccordingly, even if the port liner 3 is divided into parts to facilitate installation into the bent exhaust port 2, the upstream liner 3a is connected to the exhaust valve The inserted rear end is fixed to the exhaust valve seat 5 etc. in the exhaust port immediately after, and the downstream liner 3b is overlapped and connected to the inside end of the upstream liner 3a to form an integral continuous port liner. In particular, the downstream liner 3b can have a heat-retaining structure on the inner wall within the exhaust port over its entire area.

Further, the downstream liner 3b has a connection structure in which the insertion inner end thereof is fitted to the inside of the end of the upstream liner 3a so as to overlap, and the overlapping part 6 is fixed by spot welding or the like. The joint portion of the downstream liner 3b) has a double structure, which increases the strength of the liner.

Furthermore, in the connection configuration as described above, a step is formed on the outer periphery of the downstream liner 3b at the overlapping portion 6, and this step creates a gap between the back surface of the downstream liner 3b and the inner wall of the port. By supporting the exhaust port outlet side on the port inner wall with the ring-shaped collar 7, the downstream liner 3b can be installed inside the exhaust port 2 with a required heat insulating gap provided on the back surface over the entire area.

Moreover, in the interior state, in the downstream liner 3b, only the part of the collar 7 on the exhaust port outlet side contacts the port inner wall, and the other parts do not contact the port inner wall. By configuring the side liner 3a to be short and the downstream liner 3b to be long and divided, the contact area between the liner and the head can be significantly reduced, reducing the amount of heat conduction from the liner to the head and improving the exhaust port. It can enhance the heat retention effect.

In addition, in the port liner 3, the insertion rear end of the upstream liner 3a is fixed to the exhaust valve seat, etc., but the downstream liner 3b connected to this is fixed to the collar 7 on the exhaust port outlet side.
Since the liner is slidably supported on the inner wall of the port, and the entire downstream side of the liner is supported in a floating state with respect to the inner wall of the port, stress generation due to thermal expansion can be prevented and thermal strength can be increased.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a cylinder head of an exhaust port portion showing an embodiment of the present invention, and FIG. 2 is a view taken in the direction of arrow A in FIG. 1...Cylinder head, 2...Exhaust port, 3...Port liner, 3a...
Upstream liner, 3b...Downstream liner, 5...
...Exhaust valve seat part, 6...Overlapping part, 7.
...Tsuba.

Claims (1)

[Claims] 1. A port liner that is internally installed throughout the exhaust port of the cylinder head is divided into multiple pieces in the flow direction of exhaust gas to form a split liner, and the most upstream liner of the split liner is placed on the exhaust valve side. Insert the downstream liner into the exhaust port through the opening and fix the inserted rear end to the exhaust valve seat, etc., and insert the downstream liner into the exhaust port through the opening on the other exhaust pipe connection side and secure the inserted inner end. The upstream liner is fitted to the inside of the end of the upstream liner so as to overlap, and the upstream liner and the downstream liner are connected by spot welding or other means at the overlapping part, and the downstream liner is fitted on the exhaust port exit side. The insertion rear end of the liner is slidably supported with a predetermined gap between the inner wall of the port and the inner wall of the exhaust port by a ring-shaped collar fitted around its outer periphery. An exhaust port liner device for an internal combustion engine, characterized in that an adiabatic gap exists.