US5341783A — Accumulator fuel injection system

Claim 1

Independent Claim 125 words

A method of reducing undesired premixed burning in an internal combustion engine, comprising: A. lifting an injector needle of a fuel injector a constant low-lift increment from a valve seat of said fuel injector; then B. preventing lifting of said needle beyond said low-lift increment for a sufficient interval of time to inject a relatively small initial fuel charge into the engine, said interval terminating when lifting forces imposed on said needle overcome holding forces imposed on said needle by a stop plate, said stop plate having opposed first and second surfaces exposed to an ambient fluid pressure and to a fluid vapor pressure, respectively; and then C. lifting said needle to a higher lift position to inject a main fuel charge into the engine.

Claim 2

Independent Claim 125 words

A method of reducing undesired premixed burning in an internal combustion engine, comprising: A. lifting an injector needle of a fuel injector a constant low-lift increment from a valve seat of said fuel injector; then B. preventing lifting of said needle beyond said low-lift increment for a sufficient interval of time to inject a relatively small initial fuel charge into the engine, said interval terminating when lifting forces imposed on said needle overcome holding forces imposed on said needle by a stop plate, said stop plate having opposed first and second surfaces exposed to an ambient fluid pressure and to a fluid vapor pressure, respectively; and then C. lifting said needle to a higher lift position to inject a main fuel charge into the engine.

Claim 3

Dependent Claim 27 words

A method as defined in claim 1, wherein said fuel injector is a pressure intensified-type fuel injector, and wherein said ambient fluid pressure comprises intensified fluid pressure.

Claim 4

Dependent Claim 25 words

A method as defined in claim 2, wherein said intensified fluid pressure is imposed on said needle through a hole formed in said stop plate.

Claim 5

Dependent Claim 29 words

A method as defined in claim 1, wherein said preventing step commences when said needle abuts said stop plate and terminates when said stop plate lifts with said needle.

Claim 6

Dependent Claim 69 words

A method as defined in claim 4, wherein said fluid vapor pressure is formed from an essentially fluid-tight seal formed by the seating of said stop plate onto a mating flat stationary member, and wherein, when said stop plate is lifted, said seal is broken and fluid pressure at the interface between said stop plate and said stationary member increases from said fluid vapor pressure to said ambient pressure.

Claim 7

Dependent Claim 83 words

A fuel injector for an internal combustion engine comprising: A. an injector body; B. a nozzle provided on said injector body and defining an injector needle valve seat; C. an injector needle slidably received in said injector body and being normally seated on said valve seat; and D. a stop plate disposed in said injector body and being normally positioned so as to have opposed first and second surfaces thereof exposed to an ambient fluid pressure and to a fluid vapor pressure, respectively.

Claim 8

Dependent Claim 83 words

A fuel injector for an internal combustion engine comprising: A. an injector body; B. a nozzle provided on said injector body and defining an injector needle valve seat; C. an injector needle slidably received in said injector body and being normally seated on said valve seat; and D. a stop plate disposed in said injector body and being normally positioned so as to have opposed first and second surfaces thereof exposed to an ambient fluid pressure and to a fluid vapor pressure, respectively.

Claim 9

Dependent Claim 47 words

A fuel injector as defined in claim 6, wherein said second surface of said stop plate comprises a downwardly facing flat and smooth surface which is normally seated on a flat and smooth shoulder of said injector body so as to provide an essentially fluid-tight seal therebetween.

Claim 10

Dependent Claim 55 words

A fuel injector as defined by claim 7, wherein an axial clearance is formed between said stop plate and an upwardly facing surface of said injector needle when said injector needle is seated on said valve seat, said injector needle closing said clearance to abut said stop plate upon being lifted from said valve seat.

Claim 11

Dependent Claim 51 words

A fuel injector as defined in claim 8, wherein said downwardly facing surface of said stop plate has a recess formed therein the depth of which substantially defines said axial clearance, said upwardly facing surface of said injector needle entering said recess when said injector needle rises from its seated position.

Claim 12

Dependent Claim 35 words

A fuel injector as defined in claim 8, wherein said stop plate has an axial hole formed therethrough via which said ambient fluid pressure is imposed on said upwardly facing surface of said injector needle.

Claim 13

Dependent Claim 26 words

A fuel injector as defined in claim 10, further comprising a pin extending through said hole and abutting said upwardly facing surface of said injector needle.

Claim 14

Dependent Claim 22 words

A fuel injector as defined in claim 11, wherein said pin has an upper end positioned in a cavity containing pressurized fluid.

Claim 15

Dependent Claim 52 words

A fuel injector as defined in claim 18, wherein said ambient fluid pressure biases said injector needle towards said valve seat, and further comprising a needle spring which biases said injector needle towards said valve seat and a plate spring which biases said stop plate towards said shoulder of said injector body.

Claim 16

Dependent Claim 34 words

A fuel injector as defined in claim 6, wherein said fuel injector is an accumulator-type fuel injector in which the energy for injection is stored by the compression of liquid fuel within said injector.

Claim 17

Dependent Claim 36 words

A fuel injector as defined in claim 6, wherein said fuel injector is a pressure intensified-type fuel injector having a cavity exposed to intensified fluid pressure, and wherein said stop plate is provided in said cavity.

Claim 18

Dependent Claim 17 words

A fuel injector as defined in claim 6, wherein said injector needle comprises a unitary injector needle.

Claim 19

Dependent Claim 17 words

A fuel injector as defined in claim 6, wherein said injector needle comprises a two-part injector needle.

Claim 20

Dependent Claim 15 words

A fuel injector as defined in claim 6, wherein said nozzle is a sac nozzle.

Claim 21

Dependent Claim 16 words

A fuel injector as defined in claim 6, wherein said nozzle is a pintle type nozzle.

Claim 22

Independent Claim 68 words

A method of reducing undesirable premixed burning in an internal combustion engine, comprising A. raising an injector needle of an accumulator-type fuel injector off its valve seat a small constant low-lift increment for a sufficient interval of time to inject a small initial fuel charge into the engine; and then B. raising the needle to a higher lift position to inject a main fuel charge into the engine.

Claim 23

Independent Claim 68 words

A method of reducing undesirable premixed burning in an internal combustion engine, comprising A. raising an injector needle of an accumulator-type fuel injector off its valve seat a small constant low-lift increment for a sufficient interval of time to inject a small initial fuel charge into the engine; and then B. raising the needle to a higher lift position to inject a main fuel charge into the engine.

Claim 24

Dependent Claim 153 words

A fuel injector comprising: A. an injector body having (1) a longitudinal bore formed therein, (2) a nozzle formed in a bottom end of said bore and defining a needle valve seat, and (3) a pressurized cavity formed therein located above and in communication with an upper end of said bore; B. an injector needle slidably received in said bore and having a lower end normally seated on said valve seat and an upper end normally disposed proximate a junction between said pressurized cavity and said bore; and C. a stop plate disposed in said pressurized cavity and having (1) an upper surface exposed to an ambient fluid pressure in said cavity, (2) a lower surface sealingly contacting a shoulder of said injector body, and (3) a hole formed therethrough permitting the imposition of forces, generated by said ambient fluid pressure in said pressurized cavity, on said upper end of said injector needle.

Claim 25

Dependent Claim 153 words

A fuel injector comprising: A. an injector body having (1) a longitudinal bore formed therein, (2) a nozzle formed in a bottom end of said bore and defining a needle valve seat, and (3) a pressurized cavity formed therein located above and in communication with an upper end of said bore; B. an injector needle slidably received in said bore and having a lower end normally seated on said valve seat and an upper end normally disposed proximate a junction between said pressurized cavity and said bore; and C. a stop plate disposed in said pressurized cavity and having (1) an upper surface exposed to an ambient fluid pressure in said cavity, (2) a lower surface sealingly contacting a shoulder of said injector body, and (3) a hole formed therethrough permitting the imposition of forces, generated by said ambient fluid pressure in said pressurized cavity, on said upper end of said injector needle.

Claim 26

Dependent Claim 40 words

A fuel injector as defined in claim 21, wherein said stop plate has a recess formed in said lower surface thereof for receiving said upper end of said injector needle when said injector needle is lifted from said valve seat.

Claim 27

Dependent Claim 52 words

A fuel injector as defined in claim 21, wherein said ambient fluid pressure biases said injector needle towards said valve seat, and further comprising a needle spring which biases said injector needle towards said valve seat and a plate spring which biases said stop plate towards said shoulder of said injector body.

Claim 28

Dependent Claim 29 words

A fuel injector as defined in claim 21, further comprising a pin extending through said hole of said stop plate and abutting said upper end of said injector needle.

Claim 29

Dependent Claim 32 words

A fuel injector as defined in claim 21, wherein said hole in said stop plate defines a fluid flow path between said upper end of said injector needle and said pressurized cavity.

Claim 30

Dependent Claim 69 words

A fuel injector as defined in claim 21, wherein A. the pressure at an interface between said lower surface of said stop plate and said shoulder of said injector body is approximately fluid vapor pressure, and B. the net pressure forces on said stop plate are the product of 1) the interface area and 2) the difference between an ambient pressure in said pressurized cavity and said vapor pressure.

Claim 31

Independent Claim 112 words

A method of reducing undesired premixed burning of fuel in an internal combustion engine, comprising: A. first injecting a small initial charge of fuel from an accumulator-type fuel injector into said engine at a relatively low rate, said initial fuel charge being injected through a relatively small substantially constant needle aperture for a first time interval; and then B. injecting a main fuel charge into said engine at a relatively high rate which gradually decreases from an initial peak rate, said main fuel charge being injected through a relatively large substantially constant needle valve aperture for a second time interval, said relatively high rate of injection decreasing during said second time interval.

Claim 32

Independent Claim 112 words

A method of reducing undesired premixed burning of fuel in an internal combustion engine, comprising: A. first injecting a small initial charge of fuel from an accumulator-type fuel injector into said engine at a relatively low rate, said initial fuel charge being injected through a relatively small substantially constant needle aperture for a first time interval; and then B. injecting a main fuel charge into said engine at a relatively high rate which gradually decreases from an initial peak rate, said main fuel charge being injected through a relatively large substantially constant needle valve aperture for a second time interval, said relatively high rate of injection decreasing during said second time interval.

Claim 33

Dependent Claim 87 words

In an internal combustion engine accumulator-type fuel injector, a method of reducing undesirable premixed burning in the engine which comprises: A. raising an injector needle off its valve seat a small low-lift increment for a sufficient interval of time to inject a small initial fuel charge into the engine; B. then lifting the needle to a full lift position to inject the main fuel charge into the engine; and C. controlling needle lift by controlled venting of pressurized liquid from a pressurized zone located above said needle.

Claim 34

Dependent Claim 87 words

In an internal combustion engine accumulator-type fuel injector, a method of reducing undesirable premixed burning in the engine which comprises: A. raising an injector needle off its valve seat a small low-lift increment for a sufficient interval of time to inject a small initial fuel charge into the engine; B. then lifting the needle to a full lift position to inject the main fuel charge into the engine; and C. controlling needle lift by controlled venting of pressurized liquid from a pressurized zone located above said needle.

Claim 35

Dependent Claim 61 words

A method as defined in claim 28, wherein said step of controlling comprises: A. first relatively slowly venting pressurized liquid from said pressurized zone to produce said low-lift increment of lift of said injector needle; and B. then relatively rapidly venting pressurized liquid from said pressurized zone to produce said raising of said injector needle to its said full lift position.

Claim 36

Dependent Claim 92 words

A method as defined in claim 29, further comprising: A. placing a stop plate at a first stop position in which it is spaced said low-lift increment above the upper end of said injector needle prior to said relatively slow venting so as to positively stop said injector needle at its said low-lift increment of lift during said relatively slow venting; and B. releasing said stop plate from its first stop position during said relatively rapid venting so as to enable said injector needle to lift to its said full lift position.

Claim 37

Dependent Claim 46 words

A method as defined in claim 30, wherein said step of releasing said stop plate enables said stop plate to be raised to a second stop position during said relatively rapid venting so as to positively stop said injector needle at its said full lift position.

Claim 38

Dependent Claim 44 words

A method as defined in claim 31, further comprising: A. holding said stop plate in its said first stop position by fluid pressure during said relatively slow venting; and B. decreasing said fluid pressure so as to perform said releasing of said stop plate.

Claim 39

Dependent Claim 32 words

A method as defined in claim 28, wherein said controlling step comprises controlled venting of pressurized liquid from said pressurized zone so as to provide an injection rate which increases with time.

Claim 40

Dependent Claim 41 words

A method as defined in claim 28, wherein said controlling step comprises controlled venting of pressurized liquid from said pressurized zone so as to provide an injection rate which increases with time followed by an injection rate which decreases with time.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1997-08-29	1998-02-28	1998-08-30	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2001-08-29	2002-02-28	2002-08-30	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2005-08-29	2006-02-28	2006-08-30	$7700.00	Window Closed / Lapsed

Accumulator fuel injection system

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