Exhaust heat conservation
AssigneeFord Motor Company
InventorsCharles M. Jones, Hai Wu
Life of this patent
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Abstract
A method of programming exhaust gas constituents is disclosed which cooperates with a unique exhaust passage liner construction resulting in an improved self-cleaning technique for internal combustion engines. The liner comprises an apparatus which preferably subdivides the outer peripheral region of the exhaust so that the Reynolds number of the outer flow is below 2300 and therefore indicative of laminar or controlled turbulent flow. The laminar transient film between the passage wall and flow is enhanced by the transient film between subdividing walls and the flow, the composite acting to reduce the heat transfer coefficient between the total flow and wall of the exhaust passage.
Claims21
A method for controlling exhaust emissions from an internal combustion engine, comprising:
- a. inducting two phases of a combustible mixture into a combustion zone of said engine, one phase having a rich and the other a lean fuel component so that the average air/fuel ratio of both said phases is in the range of 17-20:1 at part engine load and about 14:1 at maximum torque whereby combustion will take place with excess stoichiometric oxygen,
- b. compressing and combusting said two phases of said mixture, said combustion being initiated in the rich phase so that exhaust gases resulting therefrom will contain a lower amount of unburned hydrocarbons and nitrogen oxides than carbon monoxide and oxygen, and
- c. controlling the withdrawal of exhaust gases from said combustion zone through a passage immediately adjacent said zone, said passage being defined by an outer wall and having an inner space thereof with at least the outer peripheral zone thereof subdivided to insure that flow therethrough is substantially coherently streamlined with little or no local disturbances, said flow having a reduced convective heat transfer coefficient to retain a greater amount of heat of said exhaust gases so that a higher temperature can be maintained resulting in chemical reaction of the CO and O.sub.2 content of said exhaust gases to provide a self-cleaning function.
For use in an internal combustion engine having a mass defined by a block enclosing a combustion zone in one part of said mass, an apparatus for modifying the flow character of exhaust gases, comprising:
- a. an unlined passage extending through the mass of said engine and originating from the combustion zone of said engine, said passage having an outer wall and an interior space with an outer peripheral zone and an inner peripheral zone, and
- b. means in said passage subdividing at least the outer peripheral zone of said space to effectively reduce the Reynolds number of flow through at least said outer peripheral zone to a value below 2300 whereby the heat transfer coefficient between said flow and wall is reduced.
In an internal combustion engine, having a housing containing at least one primary combustion chamber and induction means for supplying two phases, rich and lean, of a combustible mixture to said chamber, said engine having means for controlling the timing of intaking, compression, expansion and exhaust cycles, the improvement comprising:
- a. means for igniting said rich phase to initiate combustion, said rich phase and lean phase together having an average air/fuel ratio in the range of 17-20:1 at part engine load and about 14:1 at maximum torque whereby combustion will take place with excess stoichiometric oxygen,
- b. passage means through which exhaust gases from said combustion must pass to be released from said housing, and
- c. means subdividing at least a portion of the interior of said passage means so that laminar flow is substantially devoid of local disturbances resides in the peripheral regions of said passage means.
Dependencies are inferred from the claim text.