Fuel feed device for an internal combustion engine

Claim 2

A fuel feed device for use in crank chamber compression-type two-cycle engines, comprising a first chamber and a second chamber separated by a movable member, means for communicating said first chamber with the crank chamber of said engine, a pump member operatively connected with said movable member, a pump chamber the volume of which varies incident to movement of said pump member, and valve means operative such that fuel is sucked into said pump chamber incident to movement of said pump member when said movable member moves from said first chamber toward said second chamber and is discharged therefrom incident to reverse movement of said pump member.

Claim 3

A fuel feed device according to claim 1, wherein said movable member is a diaphragm.

Claim 4

A fuel feed device according to claim 1, wherein said movable member is a piston.

Claim 5

A fuel feed device according to claim 1, wherein said pump member is a plunger.

Claim 6

A fuel feed device according to claim 1, wherein said pump member is a diaphragm.

Claim 7

A fuel feed device according to claim 1, wherein a stopper is provided to limit the movement of said pump member in the fuel discharging direction such that the amount of movement of said pump member is proportional to the maximum value of the positive pressure in the crank chamber.

Claim 8

A fuel feed device according to claim 6, wherein a fuel passage leading from the pump chamber is formed through said stopper and said fuel passage is closed when the pump member abuts against said stopper.

Claim 9

A fuel feed device according to claim 1, wherein means is provided to communicate said second chamber with the intake passage of the engine.

Claim 10

A fuel feed device according to claim 8, wherein said means to communicate said second chamber with the intake passage of the engine includes a passage opening at a location downstream of a choke valve provided in the engine intake passage.

Claim 11

A fuel feed device for use in crank chamber compression-type two-cycle engines, comprising a casing having a cavity therein, a movable member dividing said cavity into a first chamber and a second chamber, means for communicating said first chamber with the crank chamber of the engine, a pump chamber formed in said casing in adjacent relation to said first chamber, a plunger slidably received in a bore communicating said first chamber and said pump chamber with each other, means for urging said plunger into abutting engagement at one end with said movable member, valve means operative such that fuel is discharged from said pump chamber incident to movement of said plunger toward said pump chamber and is sucked into said pump chamber incident to reverse movement of said plunger, an annular groove formed in the wall of said bore in a manner to encircle said plunger, and means for communicating said annular groove with the suction passage of the engine.

Claim 12

A fuel feed device for use in crank chamber compression-type two-cycle engines, comprising a casing having a cavity therein, a movable member dividing said cavity into a first chamber and a second chamber, means for communicating said first chamber with the crank chamber of the engine, a pump chamber formed in said casing in adjacent relation to said first chamber, a plunger slidably received in a bore communicating said first chamber and said pump chamber with each other, means for urging said plunger into abutting engagement at one end with said movable member, valve means operative such that fuel is discharged from said pump chamber incident to movement of said plunger toward said pump chamber and is sucked into said pump chamber incident to reverse movement of said plunger, an annular groove formed in the wall of said bore in a manner to encircle said plunger, and means for communicating said annular groove with the suction passage of the engine.

Claim 13

A fuel feed device for use in crank chamber compression-type two-cycle engines, comprising a casing haviNg first and second cavities therein, a first diaphragm dividing said first cavity into a first pressure chamber and a first air chamber, a second diaphragm dividing said second cavity into a second pressure chamber and a second air chamber, said first and second pressure chamber being on the same side with respect to the respective diaphragms and said first and second air chambers being on the same side with respect to the respective diaphragms, means for communicating said first and second pressure chambers with the crank chamber of the engine, a plunger slidably disposed in said casing with the opposite end thereof in abutting engagement with said first and second diaphragms respectively, a pump chamber defined by said plunger and said casing and the volume of which increases incident to movement of said plunger when the pressure in the crank chamber increases, and valve means operative such that fuel is sucked into the pump chamber when the volume of said pump chamber increases and discharged therefrom when said volume decreases.

Claim 14

A fuel feed device for use in crank chamber compression-type two-cycle engines, comprising a casing haviNg first and second cavities therein, a first diaphragm dividing said first cavity into a first pressure chamber and a first air chamber, a second diaphragm dividing said second cavity into a second pressure chamber and a second air chamber, said first and second pressure chamber being on the same side with respect to the respective diaphragms and said first and second air chambers being on the same side with respect to the respective diaphragms, means for communicating said first and second pressure chambers with the crank chamber of the engine, a plunger slidably disposed in said casing with the opposite end thereof in abutting engagement with said first and second diaphragms respectively, a pump chamber defined by said plunger and said casing and the volume of which increases incident to movement of said plunger when the pressure in the crank chamber increases, and valve means operative such that fuel is sucked into the pump chamber when the volume of said pump chamber increases and discharged therefrom when said volume decreases.

Claim 15

A fuel feed device according to claim 11, wherein the casing is formed with an annular groove encircling said plunger and means is provided to communicate said annular groove with the suction passage of the engine.

Claim 16

A fuel feed device according to claim 11, wherein said first and second air chambers are communicated with the suction passage of the engine.

Claim 17

A fuel feed device for use in crank chamber compression-type two-cycle engines, comprising a casing having a first cavity and a second cavity therein, a first diaphragm dividing said first cavity into a pressure chamber and a first air chamber, a second diaphragm dividing said second cavity into a pump chamber and a second air chamber, said first and second air chambers being on the same side with respect to the respective diaphragms, means for communicating said pressure chamber with the crank chamber of the engine, a slidable connecting rod operatively connecting said first and second diaphragms with each other, and valve means operative such that it permits fuel to flow into said pump chamber incident to movement of the second diaphragm in a direction to increase the volume of said pump chamber and to be discharged therefrom incident to reverse movement of said diaphragm.

Claim 18

A fuel feed device for use in crank chamber compression-type two-cycle engines, comprising a casing having a first cavity and a second cavity therein, a first diaphragm dividing said first cavity into a pressure chamber and a first air chamber, a second diaphragm dividing said second cavity into a pump chamber and a second air chamber, said first and second air chambers being on the same side with respect to the respective diaphragms, means for communicating said pressure chamber with the crank chamber of the engine, a slidable connecting rod operatively connecting said first and second diaphragms with each other, and valve means operative such that it permits fuel to flow into said pump chamber incident to movement of the second diaphragm in a direction to increase the volume of said pump chamber and to be discharged therefrom incident to reverse movement of said diaphragm.

Claim 19

A fuel feed device according to claim 14, wherein said first and second air chambers are communicated with the suction passage of the engine.

Claim 20

A fuel feed device for use in crank chamber compression-type two-cycle engines, comprising a casing having first and second cavities, a piston dividing said first cavity into a first chamber remote from said second cavity and a second chamber close to said second cavity, means for communicating said first chamber with the crank chamber of the engine, means for communicating said second chamber and second cavity with the suction passage of the engine, a bore formed in the casing and opening into said second chamber at one end and into said second cavity at the other end, a plunger slidably disposed in said bore, elastic means for urging said plunger against said diaphragm, a pump chamber formed between said plunger and said casing and the volume of which increases incident to movement of said plunger toward said second cavity, and valve means operative such that fuel is sucked into said pump chamber when the volume of said pump chamber increases and discharged therefrom when said volume decreases.

Claim 21

A fuel feed device for use in crank chamber compression-type two-cycle engines, comprising a casing having first and second cavities, a piston dividing said first cavity into a first chamber remote from said second cavity and a second chamber close to said second cavity, means for communicating said first chamber with the crank chamber of the engine, means for communicating said second chamber and second cavity with the suction passage of the engine, a bore formed in the casing and opening into said second chamber at one end and into said second cavity at the other end, a plunger slidably disposed in said bore, elastic means for urging said plunger against said diaphragm, a pump chamber formed between said plunger and said casing and the volume of which increases incident to movement of said plunger toward said second cavity, and valve means operative such that fuel is sucked into said pump chamber when the volume of said pump chamber increases and discharged therefrom when said volume decreases.