Abstract A spark plug is caused to spark at a point in the exhaust passageway immediately downstream from the exhaust port of each cylinder of an engine immediately after full closure of the exhaust port during the compression stroke in order to cause combustion of some fuel-air gas unavoidably blown past the exhaust port into the exhaust passageway as charge-loss gas before full closure of the port. A small quantity of supplementary fuel-air gas can be supplied as pilot gas with or without supplemental air to the spark gap to facilitate and ensure positive ignition and combustion. Other refinements include a precombustion chamber around the spark gas and control devices for causing the pilot gas to be supplied only when this supply of pilot gas is advantageous.
In a two-stroke-cycle engine having at least one piston and corresponding cylinder with an exhaust port having an upper edge lip past which the piston in ascending stroke passes to close fully the exhaust port, said port communicating contiguously with an exhaust outlet passageway, an exhaust gas cleaning device comprising an ignition chamber disposed in said passageway immediately downstream from the exhaust port and having a narrow inlet opening confronting said lip of the exhaust port in close proximity thereto, an iGnition spark plug disposed so that its spark gap projects into the ignition chamber, and ignition means to cause the spark plug to spark immediately after full closure of the exhaust port.
Claim 2
Dependent Claim
113 words
In a two-stroke-cycle engine having at least one piston and corresponding cylinder with an exhaust port having an upper edge lip past which the piston in ascending stroke passes to close fully the exhaust port, said port communicating contiguously with an exhaust outlet passageway, an exhaust gas cleaning device comprising an ignition chamber disposed in said passageway immediately downstream from the exhaust port and having a narrow inlet opening confronting said lip of the exhaust port in close proximity thereto, an iGnition spark plug disposed so that its spark gap projects into the ignition chamber, and ignition means to cause the spark plug to spark immediately after full closure of the exhaust port.
Claim 3
Dependent Claim
68 words
The exhaust gas cleaning device as claimed in claim 1 in which the spark plug is provided with a central anode extended to a tip and a bottle-shaped cathode having a hollow interior containing the anode and having a constricted neck surrounding said tip thereby to form an annular spark gap therebetween, a small quantity of pilot gas being supplied to the spark gap through said hollow interior.