Patent Application
20170241550
The present disclosure relates generally to the field of fuel injectors. In particular, the present disclosure relates to a seal member for a fuel injector.
Modern fuel injectors are actuated mechanically, hydraulically, electrically, electronically or by a combination of these mechanisms. These mechanisms are used to move a valve that blocks flow of fuel out of the injectors and into the combustion chamber. Some of these mechanisms use hydraulic oil for actuating parts of the fuel injectors. Thus, a possibility of mixing of hydraulic oil and fuel exists and threatens smooth operation of engines using these injectors.
The possibility of mixing of hydraulic oil and fuel inside injectors may be reduced or eliminated by using a seal member. These seal members, when exposed to the hydraulic oil, may be susceptible to abrasion because of the soot suspended in the hydraulic oil. The problem of seal members being abraded may further be escalated by their typical geometry.
U.S. Pat. No. 6,659,371 discloses a seal having an upper and a lower seal, for preventing the intrusion of liquid fuel into the working moving parts of the fuel injector. The document discloses a seal having an upper cap and a lower cap wherein both the upper and lower cap have substantially radially extending flares.
The present disclosure provides for a valve system. The valve system includes a guide member having a passage, a generally annular seal member positioned relative to the passage, and a valve stem disposed within the guide member passage to move axially relative to the guide member and the seal member. The seal member has an inner circumferential surface defining a bore, an outer circumferential surface, and an intermediate seal portion therebetween. The intermediate seal portion includes a first axial end surface and a second axial end surface. The seal member further includes a ramp on at least one of the first axial end surface and the second axial end surface. The ramp is descending from the inner circumferential surface to one of the intermediate seal portion or the outer circumferential surface.
The present disclosure further provides for a fuel injector system. The fuel injector system includes an injector body and a valve system disposed within the injector body. The valve system includes a guide member having a passage, a generally annular seal member positioned relative to the passage, and a valve stem disposed within the guide member passage to move axially relative to the guide member and the seal member. The seal member has an inner circumferential surface defining a bore, an outer circumferential surface, and an intermediate seal portion therebetween. The intermediate seal portion includes a first axial end surface and a second axial end surface. The seal member further includes a ramp on at least one of the first axial end surface and the second axial end surface. The ramp is descending from the inner circumferential surface to one of the intermediate seal portion or the outer circumferential surface.
In yet another aspect, a seal member of generally annular shape is disclosed. The seal member includes an inner circumferential surface defining a bore, an outer circumferential surface, and an intermediate seal portion therebetween. The intermediate seal portion includes a first axial end surface and a second axial end surface. The seal member further includes a ramp on at least one of the first axial end surface and the second axial end surface. The ramp is descending from the inner circumferential surface to one of the intermediate seal portion or the outer circumferential surface.
Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
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The present disclosure discloses the fuel injector system 100 with the valve system 110. The disclosure provides restriction on mixing of fuel in a pressurized state and engine oil, the restriction being facilitated by the seal member 128 of the valve system 110. The disclosure provides for the seal member 128 having the bore 134 and positioned relative to the passage 124 of the guide member 122, and located in the recess 123. The disclosure further provides for the valve stem 130 disposed within the passage 124 of the guide member 122, and the bore 134 of the seal member. The seal member 128 having the ramp 140 descending from the inner circumferential surface 132 to one of the intermediate seal portion 138 or the outer circumferential surface 136, so that the mixing of pressurized fuel and engine oil may be avoided.
In an aspect of the present disclosure, the solenoid valve 112 is actuated and engine oil enters the intensifier assembly 114. The intensifier piston 116 is moved by engine oil thereby moving the intensifier plunger 118. The larger ratio of surface areas of the intensifier piston 116 and the intensifier plunger 118 helps in pressurizing the fuel present in the intensifier chamber 120. This pressurized fuel is allowed or blocked to flow inside a combustion chamber (not shown) by axial movement of the valve stem 130 and thereby of the second end 148, relative to the guide member 122 and the seal member 128. The axial movement of the valve stem 130 is carried out by the pressure of engine oil on the piston 150 attached to the first end 146 of the valve stem 130. The ramp 140 on one of the first axial end surface 142 and the second axial end surface 144 of the seal member 128 restricts the mixing of pressurized fuel and engine oil. The plate member 126 vitiates any unnecessary movement of the seal member 128 located in the recess 123.
In an aspect of the present disclosure, the seal member 128 for restricting intermixing of fuel and engine oil is disclosed. The ramp 140 of the seal member 128 is placed at the valve stem 130 to the passage 124 interface and thus reduces the likelihood of accumulation of debris/impurities. This in turn increases the longevity of the seal member 128 because of reduced corrosive impact of the debris/impurities.
The seal member 128 with the ramp 140 provided on both the first axial end surface 142 and the second axial end surface 144 provides for an option of retrofitting existing fuel injector systems with seals of different geometries. This is achieved because the ramp 140 on the first axial end surface 142 helps in non-accumulation of debris, while the ramp 140 on the second axial end surface 144 helps in plugging the deficiency of the existing or abraded geometries of presently used seals. For example, the second seal member 154 may be located in the recess 123, and placed below and abutting the seal member 128. This also obviates any need of replacing any existing seals with faulty geometry inside any injector system.
The seal member 128 with the ramp 140 eases the process of routine repair of the fuel injector system 100 with the valve system 110 without the need of replacing existing seals with faulty geometries. This also increases the operating time of any existing fuel injector systems.
