The present invention relates to a fuel injector for injecting fuel into a combustion chamber of an internal combustion engine, and more particularly to such a fuel injector with locating pins which orient the fuel injector relative to the combustion chamber and prevent rotation of the fuel injector.
Fuel systems in modern internal combustion engines commonly inject fuel directly into a combustion chamber of the internal combustion engine. The fuel injector includes a nozzle body which is inserted into a fuel injector receiving bore of the internal combustion engine along a nozzle body axis. In order to achieve optimal combustion of the fuel provided by the fuel injector, thereby maximizing fuel efficiency and minimizing harmful exhaust emissions, it is known to orient the fuel injector relative to the combustion chamber in such a way that is most conducive of achieving optimal combustion. One known way to orient the fuel injector is illustrated in U.S. Pat. No. 7,886,717 to Rettig et al. where the fuel injector is provided with a fixation device which is received within a recess of the internal combustion engine which limits the extent to which the nozzle body is able to rotate within the fuel injector receiving bore. The fixation device of Rettig et al. is a feature which is formed in a plastic injection molding process with a valve housing of the fuel injector. In arrangements such as Rettig et al., the fixation device is designed to provide a clearance fit with the recess in order to accommodate for manufacturing variations when forming the fixation device. This clearance fit allows for some rotation of the fuel injector about the nozzle body axis, thereby resulting in variations in how the spray from the fuel injector is introduced into the combustion chamber. As a result, the spray from the fuel injector may not be optimally placed in the combustion chamber which may lead to reduced fuel economy and increased harmful exhaust emissions.
What is needed is a fuel injector which minimizes or eliminates one or more of the shortcomings as set forth above.
Briefly described, a fuel injector is provided by the present invention for injecting fuel into a combustion chamber of an internal combustion engine. The fuel injector includes a nozzle body configured to be inserted into a fuel injector receiving bore of the internal combustion engine along a nozzle body axis; a valve housing held in fixed relationship to the nozzle body; and a first locating pin and a second locating pin each extending from the valve housing, the first locating pin extending from a first locating pin fixed end which is fixed to the valve housing to a first locating pin free end and the second locating pin extending from a second locating pin fixed end which is fixed to the valve housing to a second locating pin free end, the first locating pin and the second locating pin collectively being configured to be inserted into a locating bore which elastically deforms the first locating pin and the second locating pin, thereby preventing rotational movement of the fuel injector about the nozzle body axis. An internal combustion engine including the fuel injector is also provided by the present invention. A method of assembling the fuel injector to the internal combustion engine is also provided by the present invention. The method includes inserting the nozzle body into the fuel injector receiving bore; inserting the first locating pin and the second locating pin into the locating bore; and elastically deforming the first locating pin and the second locating pin while the first locating pin and the second locating pin are being inserted into the locating bore such that the first locating pin and the second locating pin radially orient the nozzle body in the fuel injector receiving bore and thereby preventing rotation movement of the fuel injector about the nozzle body axis.
The fuel injector, internal combustion engine, and method of assembling the fuel injector to the internal combustion engine included herein provide for positive orientation, by forcing the locating pins collectively to be centered in the locating bore, of the fuel injector relative to the combustion chamber of the internal combustion engine which is necessary to achieve desired combustion of the fuel, thereby maximizing fuel efficiency, minimizing harmful exhaust emissions, and minimizing variation in fuel injector to combustion chamber placement.
Further features and advantages of the invention will appear more clearly on a reading of the following detailed description of the preferred embodiment of the invention, which is given by way of non-limiting example only and with reference to the accompanying drawings.
This invention will be further described with reference to the accompanying drawings in which:
In accordance with a preferred embodiment of this invention and referring initially to
Fuel injector 10 generally includes a nozzle body 16 which is configured to be inserted into a fuel injector receiving bore 18 of internal combustion engine 12 along a nozzle body axis 20 such that a nozzle tip 24 communicates with combustion chamber 14 and includes one or more nozzle openings 26 therein from which fuel is selectively discharged from fuel injector 10 into combustion chamber 14. The discharge of fuel from nozzle openings 26 is controlled by a valve needle 28 located within nozzle body 16 where valve needle 28 is selectively seated with a valve seat 30 (shown in solid lines in the enlarged portion of
Fuel injector 10 also includes a valve housing 42 which is distal from nozzle tip 24. Valve housing 42 is held in fixed relationship to nozzle body 16 such that relative movement between valve housing 42 and nozzle body 16 is prevented. Valve housing 42 is made of a thermoplastic material which is preferably formed in a plastic injection molding process where liquefied plastic is injected into a mold (not shown) where the liquefied plastic is allowed to solidify before being removed from the mold. Valve housing 42 includes a valve housing first portion 42a which is used to fix valve housing 42 relative to nozzle body 16, a valve housing electrical connector 42b which includes electrical terminals 44 therein for providing electrical connection to actuator 32, and a valve housing intermediate portion 42c which joins valve housing first portion 42a to valve housing electrical connector 42b. Valve housing electrical connector 42b is configured to mate with a complementary electrical connector (not shown) which makes electrical connection with electrical terminals 44 to selectively supply electric current thereto.
In order to achieve desired combustion which produces low levels of emissions, nozzle tip 24 must be properly oriented with respect to combustion chamber 14 about nozzle body axis 20, thereby allowing fuel emitted from nozzle openings 26 to be introduced into combustion chamber 14 in such a way as to promote efficient combustion. It is important to note that the desired orientation of nozzle tip 24 with respect to combustion chamber 14 is dependent on may factors which may be, by way of non-limiting example only, the location of fuel injector receiving bore 18 relative to combustion chamber 14 and the location of a spark plug (not shown) which may be used to ignite the fuel. Furthermore, a practitioner of ordinary skill in the art would be able to determine the desired orientation of nozzle tip 24 with respect to combustion chamber 14, for example, through modeling or empirical testing. Fuel injector 10 includes a first locating pin 46 extending from valve housing 42 and a second locating pin 47 also extending from valve housing 42. First locating pin 46 and second locating pin 47 are configured to be collectively inserted into a locating bore 48 in order to ensure proper orientation of nozzle tip 24 with respect to combustion chamber 14 about nozzle body axis 20 such that first locating pin 46 and second locating pin 47 collectively prevent rotational movement of fuel injector 10 about nozzle body axis 20 through elastic deformation of first locating pin 46 and second locating pin 47. Locating bore 48 may be located in the same portion of internal combustion engine 12 within which fuel injector receiving bore 18 is located or may be located in another element which is otherwise maintained in a fixed position relative to combustion chamber 14. First locating pin 46 and second locating pin 47 will be described in greater detail in the paragraphs that follow.
Now with addition reference to
First locating pin 46 includes a first locating pin first surface 46c which is planar and a first locating pin second surface 46d which is planar and parallel to first locating pin first surface 46c such that imaginary ray 58 passes through first locating pin first surface 46c and first locating pin second surface 46d. A first locating pin third surface 46e is planar and extends between first locating pin first surface 46c and first locating pin second surface 46d where first locating pin third surface 46e joins first locating pin first surface 46c and first locating pin second surface 46d with, for example, one or more radii, as shown. Opposing first locating pin third surface 46e is a first locating pin fourth surface 46f which is curvilinear and extends between first locating pin first surface 46c and first locating pin second surface 46d. First locating pin fourth surface 46f includes a first locating pin contact pad 46g projecting outward therefrom at length 54 which is configured to engage locating bore 48 in order to elastically deform first locating pin 46 when first locating pin 46 is inserted into locating bore 48. A first locating pin fifth surface 46h extends between first locating pin first surface 46c and first locating pin second surface 46d and also between first locating pin free end 46b and first locating pin fourth surface 46f such that first locating pin fifth surface 46h is planar and is tapered outward such that first locating pin fifth surface 46h causes the cross sectional area of first locating pin 46, i.e. perpendicular to locating pin axis 50, to increase in a direction from first locating pin free end 46b to first locating pin fourth surface 46f. A first locating pin sixth surface 46i extends between first locating pin first surface 46c and first locating pin second surface 46d and also from first locating pin fourth surface 46f toward first locating pin fixed end 46a such that first locating pin sixth surface 46i is planar and is tapered inward such that first locating pin sixth surface 46i causes the cross sectional area of first locating pin 46, i.e. perpendicular to locating pin axis 50, to decrease in a direction from first locating pin fourth surface 46f toward first locating pin fixed end 46a. The tapered nature of first locating pin fifth surface 46h and first locating pin sixth surface 46i allows for easy insertion of first locating pin 46 into locating bore 48.
Second locating pin 47 includes a second locating pin first surface 47c which is planar and a second locating pin second surface 47d which is planar and parallel to second locating pin first surface 47c such that imaginary ray 58 extends through second locating pin first surface 47c and second locating pin second surface 47d. A second locating pin third surface 47e is planar and extends between second locating pin first surface 47c and second locating pin second surface 47d where second locating pin third surface 47e joins second locating pin first surface 47c and second locating pin second surface 47d with, for example, one or more radii, as shown. Opposing second locating pin third surface 47e is a second locating pin fourth surface 47f which is curvilinear and extends between second locating pin first surface 47c and second locating pin second surface 47d. Second locating pin fourth surface 47f includes a second locating pin contact pad 47g projecting outward therefrom at length 54 which is configured to engage locating bore 48 in order to elastically deform second locating pin 47 when second locating pin 47 is inserted into locating bore 48 and which is diametrically opposed to first locating pin contact pad 46g. As used herein, “diametrically opposed” includes being exactly diametrically opposed, i.e. spaced 180° apart about locating pin axis 50, and also includes deviations from being exactly diametrically opposed of up to 10° about locating pin axis 50. A second locating pin fifth surface 47h extends between second locating pin first surface 47c and second locating pin second surface 47d and also between second locating pin free end 47b and second locating pin fourth surface 47f such that second locating pin fifth surface 47h is planar and is tapered outward such that second locating pin fifth surface 47h causes the cross sectional area of second locating pin 47, i.e. perpendicular to locating pin axis 50, to increase in a direction from second locating pin free end 47b to second locating pin fourth surface 47f. A second locating pin sixth surface 47i extends between second locating pin first surface 47c and second locating pin second surface 47d and also from second locating pin fourth surface 47f toward second locating pin fixed end 47a such that second locating pin sixth surface 47i is planar and is tapered inward such that second locating pin sixth surface 47i causes the cross sectional area of second locating pin 47, i.e. perpendicular to locating pin axis 50, to decrease in a direction from second locating pin fourth surface 47f toward second locating pin fixed end 47a. The tapered nature of second locating pin fifth surface 47h and second locating pin sixth surface 47i allows for easy insertion of second locating pin 47 into locating bore 48.
First locating pin contact pad 46g and second locating pin contact pad 47g each extend around the periphery of a circumcircle 60 which circumscribes first locating pin contact pad 46g and second locating pin contact pad 47g for no more than 10° about locating pin axis 50. Furthermore, a first distance 62 radially outward from a point on locating pin axis 50 to first locating pin contact pad 46g is no more than 10% greater than a second distance 64 radially outward from the point on locating pin axis 50 to first locating pin fourth surface 46f. Similarly, a third distance 66 radially outward from a point on locating pin axis 50 to second locating pin contact pad 47g is no more than 10% greater than a fourth distance 68 radially outward from the point on locating pin axis 50 to second locating pin fourth surface 47f.
In order to assemble fuel injector 10 to internal combustion engine 12, nozzle body 16 is first aligned with, and inserted at least part way into, fuel injector receiving bore 18. Next, first locating pin 46 and second locating pin 47 are aligned with locating bore 48 and first locating pin 46 and second locating pin 47 are inserted into locating bore 48 such that inserting first locating pin 46 causes first locating pin contact pad 46g and second locating pin contact pad 47g to engage the inner periphery of locating bore 48 and such that first locating pin 46 and second locating pin 47 elastically deform, thereby preventing rotation of fuel injector 10 about nozzle body axis 20. The step of inserting first locating pin 46 and second locating pin 47 into locating bore 48 may also include inserting nozzle body 16 further into locating bore 48. Since first locating pin 46 and second locating pin 47 are provide with gap 56 therebetween, first locating pin 46 and second locating 47 are able to be elastically deformed independent of each other.
In an alternative arrangement as shown in
First locating pin 146 and second locating pin 147 each extend from valve housing 42. First locating pin 146 and second locating pin 147 are configured to be collectively inserted into locating bore 48 in order to ensure proper orientation of nozzle tip 24 with respect to combustion chamber 14 about nozzle body axis 20 such that first locating pin 146 and second locating pin 147 collectively prevent rotational movement of fuel injector 10 about nozzle body axis 20 through elastic deformation of first locating pin 146 and second locating pin 147. First locating pin 146 and second locating pin 147 will be described in greater detail in the paragraphs that follow.
First locating pin 146 and second locating pin 147 each extend from valve housing 42, and more particularly valve housing intermediate portion 42c, such that first locating pin 146 and second locating pin 147 are collectively centered about locating pin axis 150. First locating pin 146 extends from a first locating pin fixed end 146a which is fixed to valve housing 42 to a first locating pin free end 146b which terminates first locating pin 146, and similarly, second locating pin 147 extends from a second locating pin fixed end 147a which is fixed to valve housing 42 to a second locating pin free end 147b which terminates second locating pin 147. As shown in
First locating pin 146 includes a first locating pin first surface 146c which is curvilinear and convex facing away from locating pin axis 150 and also includes a first locating pin second surface 146d which is curvilinear and concave facing toward locating pin axis 150. A first locating pin third surface 146e is planar and extends between first locating pin first surface 146c and first locating pin second surface 146d where first locating pin third surface 146e joins first locating pin first surface 146c and first locating pin second surface 146d with, for example, one or more radii, as shown. A first locating pin fourth surface 146f is planar and extends between first locating pin first surface 146c and first locating pin second surface 146d. First locating pin first surface 146c includes a first locating pin contact pad 146g projecting outward therefrom at length 154 which is configured to engage locating bore 48 in order to elastically deform first locating pin 146 when first locating pin 146 is inserted into locating bore 48. As shown in the figures, first locating pin 146 is tapered from first locating pin contact pad 146g toward first locating pin free end 146b, thereby causing the cross-sectional area of first locating pin 146 to decrease from first locating pin contact pad 146g toward first locating pin free end 146b and also thereby allowing for easy insertion of first locating pin 146 into locating bore 48.
Second locating pin 147 includes a second locating pin first surface 147c which is curvilinear and convex facing away from locating pin axis 150 and also includes a second locating pin second surface 147d which is curvilinear and concave facing toward locating pin axis 150. A second locating pin third surface 147e is planar and extends between second locating pin first surface 147c and second locating pin second surface 147d where second locating pin third surface 147e joins second locating pin first surface 147c and second locating pin second surface 147d with, for example, one or more radii, as shown. A second locating pin fourth surface 147f is planar and extends between second locating pin first surface 147c and second locating pin second surface 147d. Second locating pin first surface 147c includes a second locating pin contact pad 147g projecting outward therefrom at length 154 which is configured to engage locating bore 48 in order to elastically deform second locating pin 147 when second locating pin 147 is inserted into locating bore 48 and which is diametrically opposed to first locating pin contact pad 146g. As used herein, “diametrically opposed” includes being exactly diametrically opposed, i.e. spaced 180° apart about locating pin axis 150, and also includes deviations from being exactly diametrically opposed of up to 10° about locating pin axis 150. As shown in the figures, second locating pin 147 is tapered from second locating pin contact pad 147g toward second locating pin free end 147b, thereby causing the cross-sectional area of second locating pin 147 to decrease from second locating pin contact pad 147g toward second locating pin free end 147b and also thereby allowing for easy insertion of second locating pin 147 into locating bore 48.
First locating pin contact pad 146g and second locating pin contact pad 147g each extend around the periphery of a circumcircle 160 (shown as coincident with locating bore 48 in
In order to assemble fuel injector 110 to internal combustion engine 12, nozzle body 16 is first aligned with, and inserted at least part way into, fuel injector receiving bore 18. Next, first locating pin 146 and second locating pin 147 are aligned with locating bore 48 and first locating pin 146 and second locating pin 147 are inserted into locating bore 48 such that inserting first locating pin 146 and second locating pin 147 causes first locating pin contact pad 146g and second locating pin contact pad 147g to engage the inner periphery of locating bore 48 and such that first locating pin 146 and second locating pin 147 elastically deform, thereby preventing rotation of fuel injector 10 about nozzle body axis 20. Due to first locating pin first surface 146c and first locating pin second surface 146d being curvilinear, elastic deformation of first locating pin 146 includes twisting in a plane that is perpendicular to locating pin axis 150. Similarly, due to second locating pin first surface 147c and second locating pin second surface 147d being curvilinear, elastic deformation of first locating pin 146 includes twisting in a plane that is perpendicular to locating pin axis 150. The step of inserting first locating pin 146 and second locating pin 147 into locating bore 48 may also include inserting nozzle body 16 further into locating bore 48. Since first locating pin 146 and second locating pin 147 are provide with gap 156 therebetween, first locating pin 146 and second locating 147 are able to be elastically deformed independent of each other.
It should be noted that
While this invention has been described in terms of preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow.
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20200158065 A1 | May 2020 | US |