EP0209938A1 - Fuel injection mechanical pump, in particular for internal combustion engines with controlled ignition - Google Patents

Fuel injection mechanical pump, in particular for internal combustion engines with controlled ignition Download PDF

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Publication number
EP0209938A1
EP0209938A1 EP86201185A EP86201185A EP0209938A1 EP 0209938 A1 EP0209938 A1 EP 0209938A1 EP 86201185 A EP86201185 A EP 86201185A EP 86201185 A EP86201185 A EP 86201185A EP 0209938 A1 EP0209938 A1 EP 0209938A1
Authority
EP
European Patent Office
Prior art keywords
plunger
fuel
cylinder
grooves
longitudinal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP86201185A
Other languages
German (de)
English (en)
French (fr)
Inventor
Piero Baldini
Mauro Forapianti
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Spica SpA
Piaggio and C SpA
Original Assignee
Spica SpA
Piaggio and C SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Spica SpA, Piaggio and C SpA filed Critical Spica SpA
Publication of EP0209938A1 publication Critical patent/EP0209938A1/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/20—Varying fuel delivery in quantity or timing
    • F02M59/24—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke
    • F02M59/26—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke caused by movements of pistons relative to their cylinders
    • F02M59/265—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke caused by movements of pistons relative to their cylinders characterised by the arrangement or form of spill port of spill contour on the piston

Definitions

  • the present invention relates to a mechanical pump for the injection of fuel intended for being applied in particular to internal combustion engines with controlled ignition.
  • a high injection pressure (about 40 bar) is necessary.
  • a pump of mechanical type is necessary.
  • Such a pump analogous as for the particular components and operation to the pumps adopted in the diesel cycle engines, consists in a pumping element or plunger sliding with a notable precision inside a cylinder, with a reciprocating motion controlled by the outside by means of a cam-follower system, or by an eccentric, in a desmodromic way, driven by the same engine.
  • the governing of the fuel delivery takes place generally by diverting to the outside the exceeding delivery by putting in communication, through a groove provided on the outer surface of the plunger, the delivery chamber of the pump with the fuel tank through a reflux port, according to a commonly used technique.
  • the governing of the delivery of the pump is obtained by means of the rotation of the plunger around its axis; the plunger has indeed on its outer surface a helical groove, which allows the reflux of fuel and hence carries out the governing thereof by fractions of its total stroke, univocally depending on the angular position of the plunger inside the cylinder in side which it runs.
  • the necessary amount of fuel per engine revolution increases with the increasing of the engine rotation rate in accordance with an equal increase of the intaken air up to the point of optimum proportioning of the engine, i.e., to the point of maximum actual average pressure corresponding to the maximum driving torque; from this point on, the necessary amount of fuel per engine re volution decreases in accordance with an equal reduction of the intaken air.
  • the injection pump as described would feed the motor with an increasing amount of fuel per engine revolution also beyond the point of maximum actual average pressure, so as to enrich too much the mix ture and to cause a malfunctioning of the engine.
  • governor devices envisages a tridimensional cam, axially moved by a centrifuge device driven by the engine, and angularly moved by the element govern ing the air intake by the engine, which actuates an element governing the angular position of the plunger of the pump and hence governing the amount of fuel injected into the engine.
  • Such a governor device guarantees a perfect pump - expensive engine coupling, but is extremely sophisticated,/ bulky and hence, among others, not much suitable to the use on small engines, such as e.g. those with the two-stroke cycle, intended for light motorvehicles and motorscooters.
  • a second type of these governor devices envisages the use of a membrane controlled by the suction pressure at the engine intake, which actuates the said pump plunger angular position governing device.
  • Such governor device is certainly simpler than the preceding one, but is less precise and is acceptable only for uses in semistationary engines, in that establishing a perfect correspondence between the suction pressure and the amount of intaken air is quite problematical.
  • Purpose of the present invention is hence to propose a mechanical injection pump for controlled-ignition engines, allowing an optimum coupling with the engine in terms of fuel feeding, avoiding the use of supplementary governor devices, and which is at the same time structural ly simple.
  • a mechanical pump for the direct injection of fuel into the combustion chamber of an internal combustion engine comprising a plunger, axially sliding inside a cylinder and rotating around its own axis, which delivers the fuel coming from a tank into a delivery chamber provided within the same cylinder towards a duct connected with the combustion chamber of the engine up to a position in the stroke of the plunger at which the fuel flows back, through ducts provided in the plunger, towards the tank, characterized in that said ducts comprise at least two helical grooves provided along the outer wall of the plunger, in communication with longitudinal grooves always provided along the outer wall of the plunger, and in communication moreover with at least a longitudinal duct provided in the plunger, said longitudinal grooves and said longitudinal duct putting the helical grooves in communication with the delivery chamber, in determined positions along the cylinder axis said helical grooves provided in the plunger being, with one of their portions, in correspondence of ports provided in the cylinder connected with the tank, for the flowing back of the fuel
  • the pump shown in fig. 1, generally indicated with 10, comprises a pump body 11 wherein a cylinder 12 and a valve body 13 are housed in a longitudinal connection relation ship.
  • valve body 13 Within the valve body 13 a shutter 15 aligned with the plunger 14 is housed.
  • a delivery chamber 16 is defined, which communicates through two transversal passageways 18 provided in the cylinder 12, with an annular chamber 19.
  • the annular chamber 19 communicates on one side, through a passageway 20, with a supply of pressurized fuel and on the other side, through a passageway 21, with a tank containing the same fuel.
  • each other helical grooves 22 On the outer wall of the plunger 14 two opposite to each other helical grooves 22 are provided, as well as two longitudinal grooves 23, they too being opposite to each other, each one of which intersecates at an end a respective helical groove 22 and ends at the other end in correspondence of the delivery chamber 16.
  • an axial duct 24 (well visible in fig. 2) is moreover provided, closed at an end, and terminating at its other end in correspondence of the delivery chamber 16.
  • the axial duct 24 communicates with the two grooves 22 by means of two transversal bores 25 always provided in the plunger 14.
  • an axial duct 26 is also provided, closed at an end, and terminating at its other end in correspondence of the delivery chamber 16.
  • two transversal through bores 27 are moreover provided, which put the axial duct 26 in communication with the outer of the shutter. The shutter is elastically pressed in closure position against a seat of the valve body 13 by a spring 28.
  • ducts 29 for the inflow of pressured oil into the seat of the cylinder 12 within which the plunger 14 slides; a duct 30 for the recovery of the fuel leaking out between the said seat of the cylinder 12 and the same cylinder; and a stud 31 preventing the cylinder 12 from rotating inside the pump body 11 are provided.
  • the plunger 14 In the position of fig. 1, the plunger 14 is in its position of lower dead point, and the fuel inflows through the passage 20, the annular chamber 19 and the passageways 18 into the delivery chamber 16. At the beginning of its stroke upwards, the plunger 14 causes the fuel to flow back into the annular chamber 19. As soon as the upper edge of the plunger 14 covers completely the ports of the passageways lb, as shown in fig. 3, the delivery geometrically starts (provided that, as in fig.
  • the longitudinal grooves 23 are not in correspondence of the ports of the passageways 18), i.e., the fuel pressurized inside the delivery chamber 16 causes the lifting and hence the opening of the shutter 15, counteracted by the spring 28; the bores 27 put the duct 26 in communication with an inner duct 32 of a delivery joint 33 connected with the engine's combustion chamber and hence the fuel outflows from the delivery chamber 16, through the duct 26, the bores 27 and the duct 32 into the said combustion chamber.
  • fig. 4 an intermediate position of the useful stroke of the piston is shown.
  • the governing of the delivery of the pump 10 is obtained by rotating the plunger 14 relatively to the cylinder 12. In fact, by varying the positioning of the upper edge of the helical grooves 22 relatively to the ports of the passageways 18, the useful stroke of the plunger 14 varies, as known, and hence the delivery.
  • the pump 10 is found to be particularly advantageous for applications to two-stroke engines which operate up to high rotation rates. It can be applied however to any internal combustion engines, whether of the controlled-ignition type or not, and hence also to a diesel engine, in those cases in which the increase of the reflux section area leads to technical advantages.
  • the delivery law of the pump 10 may be so adapted, as to fit to the intrinsic requirement of fuel by any engine types.
  • connection passageways to the reflux chamber in the disclosed and illustrated example, the annular chamber 19
  • connection bores to the axial duct of the plunger may be e.g. provided.
  • more longitudinal ducts always provided inside the plunger may be provided, serving to the same function as of the axial duct, and, e. g., each one of them may be in communication with a respective helical groove.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)
EP86201185A 1985-07-22 1986-07-07 Fuel injection mechanical pump, in particular for internal combustion engines with controlled ignition Withdrawn EP0209938A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT2166185 1985-07-22
IT21661/85A IT1200685B (it) 1985-07-22 1985-07-22 Pompa meccanica di iniezione di combustibile,in particolare permotori a combustione interna ad accensione comandata

Publications (1)

Publication Number Publication Date
EP0209938A1 true EP0209938A1 (en) 1987-01-28

Family

ID=11184986

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86201185A Withdrawn EP0209938A1 (en) 1985-07-22 1986-07-07 Fuel injection mechanical pump, in particular for internal combustion engines with controlled ignition

Country Status (5)

Country Link
EP (1) EP0209938A1 (enrdf_load_stackoverflow)
BR (1) BR8603430A (enrdf_load_stackoverflow)
ES (1) ES8705574A1 (enrdf_load_stackoverflow)
IN (2) IN164655B (enrdf_load_stackoverflow)
IT (1) IT1200685B (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1873212B (zh) * 2005-06-03 2010-10-06 曼·B及W柴油机公开股份有限公司 用于内燃机的喷射泵以及内燃机
CN101135284B (zh) * 2006-08-29 2012-11-07 曼柴油机欧洲股份公司 用于内燃机的喷射泵以及内燃机
IT201600131338A1 (it) * 2016-12-27 2018-06-27 Bosch Gmbh Robert Gruppo di pompaggio per alimentare combustibile, preferibilmente gasolio, ad un motore a combustione interna

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2429806A (en) * 1945-09-15 1947-10-28 Deschamps Fuel Injection Corp Fuel injection pump

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2429806A (en) * 1945-09-15 1947-10-28 Deschamps Fuel Injection Corp Fuel injection pump

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1873212B (zh) * 2005-06-03 2010-10-06 曼·B及W柴油机公开股份有限公司 用于内燃机的喷射泵以及内燃机
CN101135284B (zh) * 2006-08-29 2012-11-07 曼柴油机欧洲股份公司 用于内燃机的喷射泵以及内燃机
IT201600131338A1 (it) * 2016-12-27 2018-06-27 Bosch Gmbh Robert Gruppo di pompaggio per alimentare combustibile, preferibilmente gasolio, ad un motore a combustione interna
WO2018122005A1 (de) * 2016-12-27 2018-07-05 Robert Bosch Gmbh Pumpenaggregat zum zuführen von kraftstoff, bevorzugt diesel, zu einem verbrennungsmotor
CN110121593A (zh) * 2016-12-27 2019-08-13 罗伯特·博世有限公司 用于将燃料、优选柴油供应到内燃机的泵总成
US10954907B2 (en) 2016-12-27 2021-03-23 Robert Bosch Gmbh Pump unit for feeding fuel, preferably diesel fuel, to an internal combustion engine
CN110121593B (zh) * 2016-12-27 2021-05-14 罗伯特·博世有限公司 用于将燃料、优选柴油供应到内燃机的泵总成

Also Published As

Publication number Publication date
IN164656B (enrdf_load_stackoverflow) 1989-04-29
IT1200685B (it) 1989-01-27
ES556505A0 (es) 1987-05-01
IN164655B (enrdf_load_stackoverflow) 1989-04-29
IT8521661A0 (it) 1985-07-22
BR8603430A (pt) 1987-03-04
ES8705574A1 (es) 1987-05-01

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