DIAPHRAGM CARBURETOR HAVING FUEL CHANNEL SYSTEM FOR ENGINE IDLING AND ACCELERATION

• US 3,593,967 A
• Filed: 11/28/1969
• Issued: 07/20/1971
• Est. Priority Date: 11/28/1969
• Status: Expired due to Term

• Current Assignee: Tillotson Corporation
• Original Assignee: Warren D. Nutten
• Inventors: Nutten, Warren D.
• Application Number:
  US04/876,188
• Time in Patent Office: 599 Days
• US Class Current: 261/41.5
• CPC Class Codes: F02M 17/04 having fuel inlet valve controlled by diaphragm
• CPC Class Codes: Y10S 261/68 Diaphragm-controlled inlet valve

Abstract

An aspirated type of diaphragm carburetor embodying a channel system accommodating fuel for delivery into the mixing passage for engine-idling purposes and for engine acceleration wherein upon closing of the throttle valve to engine-idling position, delivery of fuel for engine-idling purposes is delayed whereby the engine operates for a short period of time on residual fuel in the crankcase before the idling system delivers fuel for engine idling, and upon opening of the throttle valve, the fuel in the idling channel system is delivered into the mixing passage through a main orifice for accelerating engine operation. The carburetor includes an unvented fuel chamber with a flexible diaphragm forming a wall of the fuel chamber. The chamber includes a valved fuel inlet with a lever transmitting movement of the diaphragm to the inlet valve. A fuel passage is disposed between the fuel chamber and the region of the main orifice. A fitting is disposed in an opening of the carburetor adjacent the mixing passage. A transverse passage is positioned in the fitting and a restricted passage between the transverse passage and the fuel chamber. An adjustable valve member having a portion projecting through the passage in the fitting and a needle valve portion cooperates with the restricted passage to regulate fuel flow from the chamber into the fitting and main orifice. A counter bore in the fitting has communication with the transverse passage. The counter bore opens into the mixing passage and provides the main fuel delivery orifice. A fuel channel conveys fuel from the transverse passage to an engine-idling orifice. A vent admits air directly into the fuel channel for delaying delivery of fuel from the fuel channel through the engine-idling orifice upon movement of the throttle valve to engine-idling position. The vent is effective upon opening movement of the throttle valve to promote rapid delivery of fuel from the fuel channel through the main orifice for engine acceleration. A supplemental chamber is located in the carburetor adjacent the idling orifice. The fuel channel includes a bore and an elongated channel is disposed normal to the bore. The elongated channel comprises a recess in an exterior surface region of the carburetor. A gasket covers the recess forming a wall of the elongated channel. One end region of the elongated channel opens into the bore. An angularly arranged channel connects the elongated channel and the supplemental chamber. The air vent admits air to the angularly arranged channel to delay delivery of fuel through the idling orifice upon movement of the throttle valve to engine-idling position.

Claims

1. In combination, a carburetor having a mixing passage and an unvented fuel chamber, a throttle valve in the mixing passage, a flexible diaphragm forming a wall of the fuel chamber, a fuel inlet, a valve for said inlet, means transmitting movement of the diaphragm to the inlet valve, main and secondary fuel delivery outlets opening into the mixing passage, fuel passage means between the fuel chamber and the region of the main outlet, means for regulating fuel flow through said passage means, a supplemental chamber in the carburetor adjacent the secondary outlet, fuel channel means in the carburetor in communication with the region of the main outlet and the supplemental chamber, said fuel channel means including a bore, an elongated channel disposed normal to the bore, said elongated channel comprising a recess in an exterior surface region of the carburetor, gasket means covering the recess forming a wall of the elongated channel, one end region of the elongated channel opening into said bore, an angularly arranged channel connecting the elongated channel and the supplemental chamber, and air vent means for admitting air to the angularly arranged to delay delivery of fuel through the secondary outlet upon movement of the throttle valve to engine-idling position.

2. In combination, a carburetor having a mixing passage and an unvented fuel chamber, a throttle valve in the mixing passage, a flexible diaphragm forming a wall of the fuel chamber, a fUel inlet, a valve for said inlet, means transmitting movement of the diaphragm to the inlet valve, a fitting disposed in an opening in the carburetor adjacent the mixing passage, a transverse passage in the fitting, a restricted passage between the transverse passage and the fuel chamber, an adjustable valve member having a portion projecting through the passage in the fitting and a needle valve portion cooperating with the restricted passage to regulate fuel flow from the chamber into the fitting, a counterbore in the fitting having communication with the transverse passage, the counterbore opening into the mixing passage providing a main fuel delivery outlet, a secondary outlet opening into the mixing passage, fuel channel means for conveying fuel from the transverse passage to the secondary outlet, and vent means admitting air directly into the fuel channel means for delaying delivery of fuel from the fuel channel means through the secondary outlet upon movement of the throttle valve to engine-idling position, said vent means being effective upon opening movement of the throttle valve to promote rapid delivery of fuel from the fuel channel means through the main outlet for engine acceleration.

3. In combination, a carburetor having a mixing passage and an unvented fuel chamber, a throttle valve in the mixing passage, a flexible diaphragm forming a wall of the fuel chamber, a fuel inlet, a valve for said inlet, means transmitting movement of the diaphragm to the inlet valve, a fitting disposed in an opening in the carburetor adjacent the mixing passage, a transverse passage in the fitting, a restricted passage between the transverse passage and the fuel chamber, and adjustable valve member having a portion projecting through the passage in the fitting and a needle valve portion cooperating with the restricted passage to regulate fuel flow from the chamber into the fitting, a counterbore in the fitting having communication with the transverse passage, the counterbore opening into the mixing passage providing a main fuel delivery outlet, a secondary outlet opening into the mixing passage, fuel channel means for conveying fuel from the transverse passage to the secondary outlet, and vent means admitting air to the fuel channel means for delaying delivery of fuel from the fuel channel means through the secondary outlet upon movement of the throttle valve to engine-idling position.

4. The combination according to claim 3 wherein the vent means includes a tubular member projecting into the air inlet region of the mixing passage.