Injection devices for compression-ignited internal combustion engines

Claim 2

An injection device for a compression-ignited internal combustion engine comprising in combination a fuel injection pump and a modifying device having a fuel take-off chamber for modifying the injection law of said injection pump and operative by taking off and restoring fuel, said injection pump comprising a body, means defining a delivery chamber in said body, a first conduit for connection to a fuel supply pump, a second conduit for connection to a fuel injector, a third conduit connected to said modifying device, injection fuel delivery means associated with said delivery chamber and capable of effecting a cyclic supply of fuel to the injector in each injection cycle and comprising first means for putting said delivery chamber alternately in communication with and out of communication with said first conduit, said second conduit and said third conduit during parts of each injection cycle and precluding communication of said delivery chamber simultaneously with said third conduit and with said first conduit, and second means interposed between and controlling communication between said third conduit and said take-off chamber so as to allow fuel to be taken off and transferred from said delivery chamber to said take-off chamber when said first means put said delivery chamber in communication with said third conduit and thereafter retard restoration of the taken-off fuel to said delivery chamber until said first means once again put said delivery chamber in communication with said third conduit in the following injection cycle.

Claim 3

An injection device as claimed in claim 1, wherein said second means comprise a take-off passage between said third conduit and said take-off chamber, and a return passage between said take-off chamber and said third conduit, said take-off passage comprising a first check valve openable to allow passage of taken-off fuel from said third conduit to said take-off chamber and means defining a bore communicating with said take-off chamber and a piston movable in said bore, a constricted passage in said piston and putting said take-off passage in communication with said take-off chamber, said return passage comprising a lateral passage which communicates laterally with said bore, means for opening and closing said lateral passage in accordance with the position of said piston, and a second check valve inserted in said return passage and openable to allow passage of taken-off fuel from said take-off chamber to said third conduit.

Claim 4

An injection device as claimed in claim 2, wherein said constricted passage is in the form of a longitudinal bore constricted in the vicinity of an end thereof adjacent said first valve, and said piston has a radial passage and a peripheral recess put in communication with said longitudinal bore by said radial passage.

Claim 5

An injection device as claimed in claim 2, wherein said modifying device comprises a hollow body having an end portion secured to said body of the injection pump, a longitudinal passage in said end portion, a valve-carrying unit carrying said first valve and second valve and a piston-carrying unit carrying said piston in said hollow body, a plug closing an end of said hollow body opposed to said end portion and retaining said units and defining said take-off chamber, said valve-carrying unit comprising a first longitudinal passage which is part of said take-off passage and a second longitudinal passage which is part of saiD return passage, said first valve and said second valve being respectively inserted in said first longitudinal passage and said second lontiguinal passage, said bore being provided in said piston-carrying unit in alignment with said first longitudinal passage.

Claim 6

An injection device as claimed in claim 2, comprising means defining abutment faces defining extreme positions of said piston and resiliently yieldable means biasing said piston to a position for opening said discharge passage.

Claim 7

An injection device as claimed in claim 4, comprising means defining abutment faces defining extreme positions of said piston and resiliently yieldable means biasing said piston to a position for opening said discharge passage, said abutment faces comprising a face on said piston-carrying unit and a face on a flange on the piston for one direction of piston movement and a face on a part of said plug and an end face of said piston for an opposite direction of movement of said piston.

Claim 8

An injection device as claimed in claim 1, further comprising a closing device interposed between said injection pump and said modifying device, said closing device being adapted and arranged to be controlled as a function of a parameter of operation of an engine for which the injection device is intended.

Claim 9

An injection device as claimed in claim 7, wherein said closing device is adapted and arranged to be actuated by an acceleration lever of the pump.

Claim 10

An injection device for a compression-ignited internal combustion engine comprising in combination a fuel injection pump and a modifying device having a fuel take-off chamber for modifying the injection law of said injection pump and operative by taking off and restoring fuel, said injection pump comprising a body, means defining a delivery chamber in said body, a first conduit for connection to a fuel supply pump, a second conduit for connection to a fuel injector, a third conduit connected to said modifying device, injection fuel delivery means associated with said delivery chamber and capable of effecting cyclic supply of fuel to the injector in each injection cycle and comprising first means for putting said delivery chamber alternately in communication with and out of communication with said first conduit, said second conduit and said third conduit during parts of each injection cycle and precluding communication of said delivery chamber simultaneously with said third conduit and with said first conduit, and second means interposed between and controlling communication between said third conduit and said take-off chamber so as to allow fuel to be taken off and transferred from said delivery chamber to said take-off chamber when said first means put said delivery chamber in communication with said third conduit and thereafter retard restoration of the taken-off fuel to said delivery chamber until said first means once again put said delivery chamber in communication with said third conduit in the following injection cycle, said pump being a distributing pump and said injection fuel delivery means being distributing means comprising a bore in said body of the pump and a rotary distributing element mounted in said bore, said delivery chamber of the pump being partly defined by a bore formed in said rotary distributing element, said first means comprising a radial passage in said rotary distributing element and communicating with said delivery chamber and adapted and arranged to be brought in communication, in the course of rotation of said rotary distributing element, in succession with said first conduit and with said third conduit.

Claim 11

An injection device for a compression-ignited internal combustion engine comprising in combination a fuel injection pump and a modifying device having a fuel take-off chamber for modifying the injection law of said injection pump and operative by taking off and restoring fuel, said injection pump comprising a body, means defining a delivery chamber in said body, a first conduit for connection to a fuel supply pump, a second conduit for connection to a fuel injector, a third conduit connected to said modifying device, injection fuel delivery means associated with said delivery chamber and capable of effecting cyclic supply of fuel to the injector in each injection cycle and comprising first means for putting said delivery chamber alternately in communication with and out of communication with said first conduit, said second conduit and said third conduit during parts of each injection cycle and precluding communication of said delivery chamber simultaneously with said third conduit and with said first conduit, and second means interposed between and controlling communication between said third conduit and said take-off chamber so as to allow fuel to be taken off and transferred from said delivery chamber to said take-off chamber when said first means put said delivery chamber in communication with said third conduit and thereafter retard restoration of the taken-off fuel to said delivery chamber until said first means once again put said delivery chamber in communication with said third conduit in the following injection cycle, said pump being a distributing pump and said injection fuel delivery means being distributing means comprising a bore in said body of the pump and a rotary distributing element mounted in said bore, said delivery chamber of the pump being partly defined by a bore formed in said rotary distributing element, said first means comprising a radial passage in said rotary distributing element and communicating with said delivery chamber and adapted and arranged to be brought in communication, in the course of rotation of said rotary distributing element, in succession with said first conduit and with said third conduit.

Claim 12

An injection device for a compression-ignited internal combustion engine comprising in combination an injection pump and a modifying device having a fuel take-off chamber for modifying the injection law of said injection pump and operative by taking off and restoring fuel, said injection pump comprising a body, a delivery chamber in said body, a first conduit for connection to a fuel supply pumP, a second conduit for connection to a fuel injector and communicating with said delivery chamber, and a third conduit connected to said modifying device, injection fuel delivery means disposed in said delivery chamber and capable of effecting a cyclic supply of fuel to the injector in each injection cycle and comprising, first means for putting said delivery chamber alternately in communication with and out of communication with said first conduit and said third conduit during parts of each injection cycle and precluding communication of said delivery chamber simultaneously with said third conduit and with said first conduit, and second means interposed and controlling communication between said third conduit and said take-off chamber so as to allow fuel to be taken off and transferred from said delivery chamber to said take-off chamber when said first means put said delivery chamber in communication with said third conduit and thereafter retard restoration of the taken-off fuel to said delivery chamber until said first means once again put said delivery chamber in communication with said third conduit in the following injection cycle, said pump being an ''''in line'''' pump and said fuel injection delivery means being a pumping element comprising a helical ramp co-operative with said inlet conduit, said first means comprising a passage in said pumping element which passage communicates with said delivery chamber, a recess in a peripheral portion of said pumping element, said passage communicating with said recess and said recess being co-operative with said third conduit.

Claim 13

An injection device for a compression-ignited internal combustion engine comprising in combination an injection pump and a modifying device having a fuel take-off chamber for modifying the injection law of said injection pump and operative by taking off and restoring fuel, said injection pump comprising a body, a delivery chamber in said body, a first conduit for connection to a fuel supply pumP, a second conduit for connection to a fuel injector and communicating with said delivery chamber, and a third conduit connected to said modifying device, injection fuel delivery means disposed in said delivery chamber and capable of effecting a cyclic supply of fuel to the injector in each injection cycle and comprising, first means for putting said delivery chamber alternately in communication with and out of communication with said first conduit and said third conduit during parts of each injection cycle and precluding communication of said delivery chamber simultaneously with said third conduit and with said first conduit, and second means interposed and controlling communication between said third conduit and said take-off chamber so as to allow fuel to be taken off and transferred from said delivery chamber to said take-off chamber when said first means put said delivery chamber in communication with said third conduit and thereafter retard restoration of the taken-off fuel to said delivery chamber until said first means once again put said delivery chamber in communication with said third conduit in the following injection cycle, said pump being an ''''in line'''' pump and said fuel injection delivery means being a pumping element comprising a helical ramp co-operative with said inlet conduit, said first means comprising a passage in said pumping element which passage communicates with said delivery chamber, a recess in a peripheral portion of said pumping element, said passage communicating with said recess and said recess being co-operative with said third conduit.