Fuel supply system

Claim 2

In a fuel system for operating an engine in idling speed and driving speed ranges, the combination of an air supply, a fuel supply including a float chamber and a fuel pump having the outlet thereof communicating with the float chamber, mixing chamber for supplying a mixture of air and fuel to the engine, a throttle valve in the chamber for controlling the supply of the air-fuel mixture to the engine, and idle metering system communicating with the float chamber and the air supply and operative to supply an air-fuel mixture to the mixing chamber downstream from the throttle valve for operating the engine in the idling speed range, a main metering system communicating with the fuel supply and operative to supply fuel to the mixing chamber for operating the engine in the driving speed range, the main metering system including main metering valve means arranged to control the fuel supplied to the mixing chamber, a positive displacement pump having the inlet thereof communicating with the float chamber and the outlet thereof communicating with the main metering valve means, and means operative in response to a predetermined pressure within the mixing chamber corresponding to the pressure at the initiation of operation of the fuel system in the driving speed range for rendering the positive displacement pump effective to supply fuel from the float chamber to the main metering valve means.

Claim 3

A fuel supply system as described in claim 1, wherein the pump operating means includes motor means for driving the pump and control means responsive to the predetermined pressure within the mixing chamber for rendering the motor means operative.

Claim 4

A fuel supply system as described in claim 1, wherein the pump operating means includes electric motor means for driving the pump, control means for the motor means, the control means including a source of electric power and switch means operative in response to the predetermined pressure within the mixing chamber for connecting the electric power source to the motor means for rendering the pump operative.

Claim 5

A fuel supply system as described in claim 1, further including enrichment valve means responsive to ambient temperatures and operative in the idling speed range when the ambient temperature is below a predetermined value to supply both air from the air supply and an air-fuel mixture from the fuel supply to the chamber at a point downstream from the throttle valve for both increasing engine speed and for enriching the mixture supplied to the engine to facilitate cold engine starting.

Claim 6

A fuel supply system as described in claim 4, wherein the main metering system further includes restrictor valve means positioned between the main metering valve means and the mixing chamber to further vary the supply of the fuel so that as the pressure within the mixing chamber approaches atmospheric pressure the supply of the mixture is reduced so as to prevent overcharging, and linkage means for connecting the throttle valve and the metering valve element for movement together.

Claim 7

In a fuel supply system for operating an engine in idling speed and driving speed ranges, the combination of an air supply, a fuel supply including a float chamber and a fuel pump having the outlet thereof communicating with the float chamber, a mixing chamber for supplying a mixture of fuel and air to the engine, a throttle valve in the chamber for controlling the supply of the mixture to the engine, an idle metering system communicating with the air supply and the float chamber and operative to supply an air-fuel mixture to the chamber downstream from the throttle valve for operating the engine in the idling speed range, and enrichment valve means responsive to ambient temperatures and operative when the ambient temperature is below a predetermined value to supply both air from the air supply and an air-fuel mixture from the fuel supply to the mixing chamber at a point downstream from the throttle valve so as to supplement the mixture supplied by the idle metering valve means and also to increase the air supply thereby increasing the engine speed and also enriching the air-fuel mixture supplied thereto to facilitate cold engine starting, a main metering system communicating with the fuel supply and operative to supply fuel to the mixing chamber for operating the engine in the driving speed range, the main metering system including a pump having an inlet thereof communicating with the float chamber and an outlet, main metering valve means including a main metering supply passage connecting the air supply and the outlet of the pump to the mixing chamber, a main metering orifice in the main metering supply passage, a main metering valve element maneuverable between open and closed settings for varying the effective size of the metering orifices and accordingly the air-fuel mixture supplied to the mixing chamber and restrictor valve means between the main metering valve element and the mixing chamber and operative in response to the suction pressure within the mixing chamber to reduce the supply of the fuel from the main metering supply passage when the suction pressure within the mixing chamber approaches atmospheric pressure so as to prevent overcharging, means operating the pump including electric motor means for driving the pump and control means for the motor means, the control means including a source of electric power and switch means responsive to a predetermined pressure within the mixing chamber corresponding to the pressure at the initiation of operation of the fuel system in the driving speed range for connecting the electric motor means to the pOwer source so as to drive the pump.

Claim 8

In a fuel supply system for operating an engine in idling speed and driving speed ranges, the combination of an air supply, a fuel supply including a float chamber and a fuel pump having the outlet thereof communicating with the float chamber, a mixing chamber for supplying a mixture of fuel and air to the engine, a throttle valve in the chamber for controlling the supply of the mixture to the engine, an idle metering system communicating with the air supply and the float chamber and operative to supply an air-fuel mixture to the chamber downstream from the throttle valve for operating the engine in the idling speed range, and enrichment valve means responsive to ambient temperatures and operative when the ambient temperature is below a predetermined value to supply both air from the air supply and an air-fuel mixture from the fuel supply to the mixing chamber at a point downstream from the throttle valve so as to supplement the mixture supplied by the idle metering valve means and also to increase the air supply thereby increasing the engine speed and also enriching the air-fuel mixture supplied thereto to facilitate cold engine starting, a main metering system communicating with the fuel supply and operative to supply fuel to the mixing chamber for operating the engine in the driving speed range, the main metering system including a pump having an inlet thereof communicating with the float chamber and an outlet, main metering valve means including a main metering supply passage connecting the air supply and the outlet of the pump to the mixing chamber, a main metering orifice in the main metering supply passage, a main metering valve element maneuverable between open and closed settings for varying the effective size of the metering orifices and accordingly the air-fuel mixture supplied to the mixing chamber and restrictor valve means between the main metering valve element and the mixing chamber and operative in response to the suction pressure within the mixing chamber to reduce the supply of the fuel from the main metering supply passage when the suction pressure within the mixing chamber approaches atmospheric pressure so as to prevent overcharging, means operating the pump including electric motor means for driving the pump and control means for the motor means, the control means including a source of electric power and switch means responsive to a predetermined pressure within the mixing chamber corresponding to the pressure at the initiation of operation of the fuel system in the driving speed range for connecting the electric motor means to the pOwer source so as to drive the pump.