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US 8,261,775 B2Granted
Layered scavenging carburetor
AssigneeWalbro Engine Management, L.L.C.
InventorsTamio Aihara, Yoshiaki Douyama, Shinichi Ohgane
Life of this patent
Estimating the term…
Abstract
A scavenging valve assembly is used in a carburetor. The valve assembly includes a throttle valve and a rotary air valve. The throttle valve opens and closes an air-fuel passage. The rotary air valve opens and closes an air passage and has one or more air bore(s). When the rotary air valve begins to rotate, airflow travels through the bore(s) and the size of an opening area that airflow travels through continuously increases in size.
Claims19
A scavenging valve assembly in a carburetor for an engine, the scavenging valve assembly comprising:
- a butterfly throttle valve opening and closing an air-fuel passage of the carburetor;
- and a rotary air valve for controlling airflow through an air scavenging passage of the carburetor, the rotary air valve having a cylindrical body with an air bore extending transversely therethrough and rotatable between an engine idle position in which the rotary air valve is not completely closed and a fully open position, a first cutout in a first open end of the air bore configured to communicate the air bore with only an upstream portion of the air scavenging passage when the rotary air valve is in its engine idle position and a second cutout in a downstream second open end of the air bore configured to communicate the air bore with only the downstream portion of the air scavenging passage when the rotary air valve is in its engine idle position so that the cutouts in conjunction with the air bore provide a continuous air flow path through the air scavenging passage from upstream of the cylindrical body through the first cutout into the air bore, through the air bore and from the air bore through the second cutout to downstream of the cylindrical body when the air valve is in its engine idle position, and, when the air valve begins to rotate from its engine idle position to its fully open position, the size of an opening area that airflow travels through the air bore continuously increases and airflow through the air bore continuously increases.
A valve assembly for use in a carburetor for an engine, the valve assembly comprising:
- a butterfly throttle valve controlling the flow through an air-fuel mixture passage of the carburetor and movable between an engine idle position in which a rotary air valve is not completely closed and a fully open position;
- and
- the rotary air valve controlling airflow through an air scavenging passage of the carburetor, the air valve having a cylindrical body with an air bore extending transversely therethrough from a first open end to a second open end and rotatable between the engine idle position and the fully open position, the air valve having a first cutout located at the first open end of the air bore configured to communicate the air bore with only an upstream portion of the air scavenging passage when the air valve is in its engine idle position and having a second cutout located at the second open end of the air bore configured to communicate the air bore with only the downstream portion of the air scavenging passage when the air valve is in its engine idle position so that the cutouts in conjunction with the air bore provide a continuous air flow path through the air scavenging passage from upstream of the cylindrical body through the first cutout into the air bore, through the air bore and from the air bore through the second cutout to downstream of the cylindrical body when the air valve is in its engine idle position;
- and
- wherein, when the air valve is in its engine idle position, airflow travels through the air bore, and wherein, as the air valve moves from its engine idle position to its fully open position, the amount of airflow through the air bore continuously increases.
2 more elements
Dependencies are inferred from the claim text.