Device for injecting liquid such as fuel into at least one pressurized chamber of a periodic operation machine such as an internal combustion engine and engine of this type equipped with this device
OwnerJean F. Melchiorinventor
Life of this patent
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Abstract
In a device for injecting liquid such as fuel into at least one pressurized chamber of a periodic operation machine such as an internal combustion engine the needle of an injector is alternately separated from its seat by the liquid pressure established by a piston pump and returned towards its seat by a liquid pressure operating on its surface remote from its conical part. This latter liquid pressure is established by connection with the cylinder of the piston pump through a calibrated orifice and a one-way valve connected in series.
Claims28
Device for injecting liquid into at least one chamber pressurized by a gas and forming part of a periodic operation machine such as an internal combustion engine, the device comprising a unit for pressurizing the liquid to be injected formed by a variable volume first cavity delimited by a piston reciprocating inside a cylinder,
- which first cavity communicates with low-pressure liquid reserve means through the intermediary of a control unit establishing such communication cyclically in synchronism with the periodic operation of said machine and via a passage that is open at all times, except for the presence of a re-aspiration valve or like unit, with an injector formed by a nozzle and a mobile needle which is a body of revolution,
- which nozzle comprises a second cavity connected to said passage and delimited laterally by a circular cylindrical wall and axially by a partially conical wall forming a seat and coaxial with said cylindrical wall and at least one injector orifice discharging into said pressurized chamber,
- which needle has a cylindrical part forming a piston and adapted to slide with minimal operating clearance inside said cylindrical wall of said nozzle and a conical part cooperating with said seat,
- which needle is adapted to be held when idle in bearing engagement with said seat by return means so as to interrupt communication between said second cavity and said injector orifice(s) and so that its cross-section bearing on said seat, when projected onto a plane perpendicular to the axis of said needle, is less than the transverse cross-section of the cylindrical part of said needle forming said piston, the free surface of said cylindrical part of said needle forming said piston delimiting a variable volume third cavity which communicates with a pressurized accumulator of said liquid and thereby constitutes said return means,
- wherein said first cavity communicates with said third cavity through a calibrated orifice and a one-way valve connected in series and in that said accumulator communicates with said low-pressure liquid reserve mean through a variable cross-section leakage orifice provided with adjustment means adapted to maintain the pressure of the liquid in said accumulator at a substantially constant value for given operating conditions during periodic operation of said machine.
Internal combustion engine with variable volume working chambers and featuring direct injection of liquid fuel into said chambers provided with a device for injecting liquid into at least one chamber pressurized by a gas and forming part of a periodic operation machine such as an internal combustion engine, the device comprising a unit for pressurizing the liquid to be injected formed by a variable volume first cavity delimited by a piston reciprocating inside a cylinder,
- which first cavity communicates with low-pressure liquid reserve means through the intermediary of a control unit establishing such communication cyclically in synchronism with the periodic operation of said machine and via a passage that is open at all times, except for the presence of a re-aspiration valve or like unit, with an injector formed by a nozzle and a mobile needle which is a body of revolution,
- which nozzle comprises a second cavity connected to said passage and delimited laterally by a circular cylindrical wall and axially by a partially conical wall forming a seat and coaxial with said cylindrical wall and at least one injector orifice discharging into said pressurized chamber,
- which needle has a cylindrical part forming a piston and adapted to slide with minimal operating clearance inside said cylindrical wall of said nozzle and a conical part cooperating with said seat,
- which needle is adapted to be held when idle in bearing engagement with said seat by return means so as to interrupt communication between said second cavity and said injector orifice(s) and so that its cross-section bearing on said seat, when projected onto a plane perpendicular to the axis of said needle, is less than the transverse cross-section of the cylindrical part of said needle forming said piston, the free surface of said cylindrical part of said needle forming said piston delimiting a variable volume third cavity which communicates with a pressurized accumulator of said liquid and thereby constitutes said return means,
- wherein said first cavity communicates with said third cavity through a calibrated orifice and a one-way valve connected in series and in that said accumulator communicates with said low-pressure liquid reserve means through a variable cross-section leakage orifice provided with adjustment means adapted to maintain the pressure of the liquid in said accumulator at a substantially constant value for given operating conditions during periodic operation of said machine.
Dependencies are inferred from the claim text.