CA1071536A

CA1071536A - Exhaust reaction chamber system of engine construction for holding adiabatic materials in vehicle's exhaust system

Info

Publication number: CA1071536A
Application number: CA266,415A
Authority: CA
Inventors: Yutaka Noritake; Soichi Nakano; Yoshitoshi Hagiwara
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1975-12-04
Filing date: 1976-11-23
Publication date: 1980-02-12
Also published as: SE7613569L; SE421644B; NL168583B; AU502898B2; NL7613430A; AU2001176A; NL168583C

Abstract

Abstract of the Disclosure An engine exhaust reaction system having an engine exhaust reaction chamber surrounded by an inner wall exposed to the heat generated in the chamber, the inner wall being enclosed is a layer of solid insulating material and confined by a thin corrugated flexible wall space from an outer wall to minimized transfer of heat thereto and to compensate for differences in thermal expansion.

Description

Conventional engine exhaust systems using an exhaust heated reaction chamber utilize an inner liner and an outer shell with clearance between them forming a chamber containing insulation material, the insulation material having a cover conforming the material to the inner liner and spacing the material from the outer shell. Conventionally such insulation retainer cover is made of metal plates essentially as thick as the inner liner; however, the temperature difference between the inner liner and the insulation retainer cover produces substantial thermal expansion of the inner liner with respect to the insulation cover, requiring the use of slidable sealing connections in place of integral connections.
It is therefore a primary object of this invention to provide an exhaust system utilizing an inner wall heated by a reaction chamber, and caused to retain its heat by insulation material, wherein the insulation material is enclosed by an insulation retainer cover formed of thin, highly flexible and corrugated metal, whereby stress on the inner wall, due to its thermal expansion, ls minimized.
According to the invention there is provided an exhaust manifold system for internal combustion engines comprising: an inner wall enclosing an exhaust reaction chamber; a body of insulating material enclosing the re-action chamber wall; a thin, highly flexible retainer wall for the insulating material having marginal portions bonded to the inner wall to confine the insulating material; and an outer wall enclosing the retainer wall and insu-lating material and spaced therefrom.
Figure 1 is a sectional side view showing one embodiment of the insulated exhaust reaction system for engines.
Figure 2 is a similar sectional view showing another embodiment thereof.
Figure 3 is a sectional view taken through 3-3 of Figure 2.
Referring first to Figure 1, the exhaust manifold includes an outer enclosure wall 2 having an upper half 3 and a lower half 4 joined by flanges 5.
Within the outer enclosure wall 2 is an inner enclosure wall 6 having an upper half 7, a lower half 8 joined by flanges 9. Between the walls 2 and 6 is a ~, reaction chamber wall 10 having an upper half 11 and a lower half 12 joined by -" rl~ D

5i3~

flanges 13.
Within the inner enclosure wall 6 is a first reaction chamber 14 and a second reaction chamber 15 separated by a baffle 16. Connected to the first reaction chamber 14 at one side is an induction passage 17 having a mounting flange 18 at its entrance end adapted to be connected to an exhaust port of an engine, not shown. The second reaction chamber 15 is connected to a passageway 19 which in turn is connected to a discharge chamber 20, disposed between the inner wall 6 and the reaction chamber wall 10.
The discharge chamber 20 is provided with a top opening 21 surround-10 ed by a marginal -flange 22 forming a part of the outer enclosure wall 2 and a marginal flange 23 forming a part of the inner enclosure reaction chamber wall lo. Interposed between the two marginal 1anges 22 and 23 is a flanged ring 24.
The lower end of the discharge chamber 20 is fitted with an outlet sleeve 25 joined to an outlet ring 26 which is joined to an exhaust pipe mounting flange 27.
Surrounding the inner enclosure wal~L 6 within the chamber between the inner enclosure wall 6 and the outer enclosure wall 2 is a relatively thick layer of insulating material 28 which may be formed of ceramic fibers or 20 carbon fibers, or the like. The insulating material is held in place by a retainer wall 29 formed of thin gauge highly flexible steel, the margin of the retainer wall 29 surrounding the opening 21 is welded to the flanged ring 24, as indicated by 30. The margin of the retainer wall surrounding the outlet sleeve 25 is welded to the sleeve or to the surrounding outlet ring 26 as indicated by 31. The retainer wall 29, like the outer enclosure 2 and the inner enclosure wall 6 is divided into an upper portion and a lower portion, ~3 the confronting margins of which are welded to the flanges~as indicated by 32. As the retainer wall 29 and the insulating material 28 may expand due to gas entrapped in the insulation material, the retainer wall 29 may be provided 3~

with appropriately located gas vents 33~
Operation of the embodiment of the insulated exhaust reaction syskem shown in Figure l is as follows:
l~hen the reaction system is in operation, a subs~antial temperature differential exists between the reaction chamber wall 10 and the insulation retainer wall 29. For example, the temperature of the wall lO may be in the order of 800 C, whereas the temperature of the insulation retaining wall 29 may be in the order of 200C. Due to its substantially higher temperatuPe, the thermal expansion and contraction of the wall 10 is substantial. The resultîng thermal stress is relieved by providing corrugations 34 which readily expand or contract.
When the exhaust reaction system is in operation, the exhaust gases flow in the manner indicated by the arrows a, b, c, d, and e. By maintaining a high temperature and increasing the effective length of the reaction region contaminates in the exhaust gases are minimized. ~he heat of reaction is also used to increase the temperature of the intake fuel mixture by placing a portion of the intake system over the opening 21. This is illustrated in Figure 2 in which is shown a portion of an intake manifold 35 having an intake passage 36 including a metal membrane wall 37 exposed to the exhaust gases.
Referring more specifically to Figures 2 and 3, most of the elements of the embodiment shown in Figures 2 and 3 are essentially the same as shown and described in connection with Figure 1, and thus bear corresponding refer-ence numeralsO
Disposed in the upper portion of the discharge cha~ber 20 is a heat distributing wall 38. ~his wall and the main or first reaction chamber 14 are provided with aligned perforations 39 and ~0; also perforations ~d--~d-~ are provided between the passageway l9 and the entrance to the dlscharge chamber 20.
An important feature shown in the embodiment represented by Figures

2 and 3 is that the marginal portions of the retainer wall 29 have increased ~7~36 thickness as indicated by 30a, 31a and 32a.
Having fully described our invention it is to be understood that we are not to be limited to the details herein set forth, but that our invention is of the full scope of the appended claims.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An exhaust manifold system for internal combustion engines compris-ing: an inner wall enclosing an exhaust reaction chamber; a body of insulat-ing material enclosing the reaction chamber wall, a thin, highly flexible retainer wall for the insulating material having marginal portions bonded to the inner wall to confine the insulating material, and an outer wall enclosing the retainer wall and insulating material and spaced therefrom.

2. An exhaust manifold system as defined in claim 1 wherein: the retainer wall includes corrugated portions positioned to compensate for thermal expansion.

3. An exhaust manifold system as defined in claim 1 wherein: the marginal portions of the retainer wall are increased in thickness for welded connection to the inner wall.

4. An exhaust manifold system as defined in claim 1 wherein said exhaust reaction chamber is a chamber system including a first reaction chamber, a second reaction chamber, a discharge reaction chamber exposed to the inner wall, and an induction passage communicating between an engine exhaust outlet and the first reaction chamber.