Internal combustion gasoline engine

• US 4,069,666 A
• Filed: 07/16/1975
• Issued: 01/24/1978
• Est. Priority Date: 11/26/1974
• Status: Expired due to Term

• Current Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Original Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Inventors: Nakamura, Hiroyuki
• Primary Examiner(s): Hart, Douglas
• Application Number:
  US05/596,522
• Time in Patent Office: 923 Days
• Field of Search: 60/293, 60/305, 60/307, 60/298, 60/278
• US Class Current: 60/278
• CPC Class Codes: F01N 3/18 characterised by methods of operation; Control
• CPC Class Codes: F01N 3/26 Construction of thermal reactors
• CPC Class Codes: F02B 1/04 with fuel-air mixture admission into cylinder
• CPC Class Codes: F02M 26/41 characterised by the arrangement of the recirculation passage in relation to the engine, e.g. to cylinder heads, liners, spark plugs or manifolds; characterised by the arrangement of the recirculation passage in relation to specially adapted combustion chambers
• CPC Class Codes: F02M 26/43 in which exhaust from only one cylinder or only a group of cylinders is directed to the intake of the engine

Abstract

An internal combustion gasoline engine for reducing undesirable exhaust emissions, hydrocarbons, carbon monoxide and nitrogen oxides mainly by means of the design techniques for exhaust passages. The present engine comprises two determined regions extending from an exhaust valve downwards in the exhaust passage so as to pass exhaust gases therethrough in their discharging order, one region having a volume permitting self-reaction of unburned constituents of exhaust gases therein at a temperature of the exhaust gases and another having so much volume and sectional area as capable of aspirating air by itself (automatically) through a check valve into the exhaust passage.

Claims

1. An exhaust gas purification system for an internal combustion engine having at least two cyclinders each having a displacement volume, comprising

an exhaust valve for each of said cylinders,

an exhaust passage comprising two branch passages each communicating with a corresponding of said exhaust valves, and an exhaust pipe having a substantially constant cross-section communicating with said two branch passages of said at least two cylinders, respectively,

said exhaust pipe having an opening end means for providing negative reflected waves,

passageway means communicating with said branch passages, respectively, and with a source of secondary air for introducing the secondary air into said exhaust passage, and including a check valve means operatively disposed in said passageway means and responsive to pulsation pressures in said exhaust passage for operatively opening and closing said passageway means.

heat insulation means in a predetermined zone of said exhaust passage extending from said exhaust valves of said at least two cylinders, respectively, for preventing the lowering of exhaust gas temperature in said predetermined zone below a predetermined temperature so as to cause sufficient self-reaction oxidation in said predetermined zone in order to have a HC concentration below 10 ppm and CO concentration below 0.1 percent, the volume of said predetermined zone being at least 2.5 times the displacement volume of said at least two cylinders, respectively,

said two branch passages of said at least two cylinders, respectively, plus said exhaust pipe defining a second volume from said exhaust valves to said opening end means being at least equal to 2.5 times the displacement volume of said at least two cylinders, respectively, and less than four times the displacement volume of said at least two cylinders, respectively, and having a cross-sectional area less than three times the total maximum opening area of said exhaust valves corresponding to said exhaust passage, whereby a necessary and sufficient amount of secondary air is substantially uniformly introduced to cause the concentration of HC and CO to be below 10 ppm and 0.1 percent, respectively.

2. An exhaust gas purification system for an internal combustion engine as set forth in claim 1, further comprising

an intake manifold,

a separate second passageway means communicating with said exhaust passage for recirculating a portion of the exhaust gases to said intake manifold.

3. An exhaust gas purification system for an internal combustion engine as set forth in claim 1, wherein

said predetermined temperature constitutes a minimum self reaction temperature for oxidation of CO and HC in said predetermined zone.

4. The system, as set forth in claim 1, further comprising

piston means for performing piston strokes in said cylinder,

said second volume and said cross-sectional area cause a continuous substantially uniform plurality of pulsation pressure waves in said exhaust passage communicating with said passageway means during all portions of each piston stroke.