Fuel pump-injector unit

Claim 2

A unit fluid pump-injector assembly (10) comprising a housing (18); a pump assembly (20) having a pump cylinder (32) and a plunger (34) therein for developing an injection charge of pressurized fluid; and an injector assembly (28) for injecting the charge of fluid through an outlet (112); characterized in that a first means (26) is provided for removably retaining the pump cylinder (32) against the housing (18); and that a second means (30) is provided for removably retaining the injector assembly (28) against the first means (26) so that the injector assembly (28) may be removed from or assembled to the first retaining means (26) without altering the position or arrangement of the pump assembly (20) relative to the first retaining means (26).

Claim 3

A unit fluid pump-injector assembly according to claim 1, characterized in that the pump assembly (20) may be removed from or assembled to the first retaining means (26) without altering the position or arrangement of the injector assembly (28) relative to the first retaining means (26).

Claim 4

A unit,fluid pump-injector assembly according to claim 1 or claim 2, wherein the first retaining means (26) includes a sleeve-type nut (68), having a plurality of stepped bores (72, 74, 76) defining a shoulder (78) and a pump cylinder retainer (70) positioned within one of the bores (74) and sealedly seating the shoulder (78).

Claim 5

A unit fluid pump-injector assembly according to claim 3, wherein the pump cylinder (32) is sealedly retained between the housing (18) and the pump cylinder retainer (70).

Claim 6

A unit fluid pump injector assembly according to claim 4, wherein the pump cylinder retainer (70) includes a fluid delivery opening (96) providing fluid communication between the pump cylinder (32) and the injector assembly (28).

Claim 7

A unit fluid pump-injector assembly according to claim 4, wherein the pump cylinder retainer (70) includes a passage (98) for returning fluid leakage from the injector assembly (28) to an annular fluid reservoir (86) surrounding the pump cylinder (32).

Claim 8

A unit fluid pump-injector assembly according to any of claims 3 to 6, wherein the injector assembly (28) is sealedly retained between the second retaining means (30) and the pump cylinder retainer (70).

Claim 9

A unit fluid pump-injector assembly according to any of claims 1 to 7, wherein the second retaining means (30) includes a second sleeve-type nut (148).

Claim 10

A unit fluid pump-injector assembly according to any of claims 1 to 8, wherein the first retaining means (26) includes a first screw-threaded portion (80) screw-threadably mated to the housing (18), and the first retaining means (26) includes a second screw-threaded portion (156) screw-threadably mated to the second retaining means (30).

Claim 11

An encapsulated injector assembly (28) adapted for use in a unit fluid pump-injector assembly (10) to inject a charge of fluid; said unit fluid pump-injector assembly (10) including a housing (18), a pump assembly (20) having a pump cylinder (32) and a plunger (34) therein for developing an injection charge of pressurized fluid, first means (26) for removably retaining said pump cylinder (32) against said housing (18) wherein said first retaining means (26) includes a sleeve-type nut (68) having a plurality of stepped bores (72, 74, 76) defining a shoulder (78), and a pump cylinder retainer (70) having a fluid delivery opening (196) and positioned within one of said bores (74), said pump cylinder retainer (70) being sealedly retained against the shoulder (78); characterised in that the injector assembly (28) includes a valve body (100), an inwardly-opening valve (102) positioned within said valve body (100), resilient means (104) for resiliently biasing the valve (102) to the closed position, and a case (106) encapsulating said valve body (100) and said resilient biasing means (104) and retaining them against separation, said injector assembly (28) adapted to be removably retained against said pump cylinder retainer (70) by a second sleeve-type nut (148) so that the injector assembly (28) may be removed from or assembled solely as a unit to the first retaining means (26) without altering the position or arrangement of the pump asssembly (20) relative to said first retaining means (26).

Claim 12

An encapsulated injector assembly (28) adapted for use in a unit fluid pump-injector assembly (10) to inject a charge of fluid; said unit fluid pump-injector assembly (10) including a housing (18), a pump assembly (20) having a pump cylinder (32) and a plunger (34) therein for developing an injection charge of pressurized fluid, first means (26) for removably retaining said pump cylinder (32) against said housing (18) wherein said first retaining means (26) includes a sleeve-type nut (68) having a plurality of stepped bores (72, 74, 76) defining a shoulder (78), and a pump cylinder retainer (70) having a fluid delivery opening (196) and positioned within one of said bores (74), said pump cylinder retainer (70) being sealedly retained against the shoulder (78); characterised in that the injector assembly (28) includes a valve body (100), an inwardly-opening valve (102) positioned within said valve body (100), resilient means (104) for resiliently biasing the valve (102) to the closed position, and a case (106) encapsulating said valve body (100) and said resilient biasing means (104) and retaining them against separation, said injector assembly (28) adapted to be removably retained against said pump cylinder retainer (70) by a second sleeve-type nut (148) so that the injector assembly (28) may be removed from or assembled solely as a unit to the first retaining means (26) without altering the position or arrangement of the pump asssembly (20) relative to said first retaining means (26).