GB2539969A

GB2539969A - Fuel unit pump for an internal combustion engine

Info

Publication number: GB2539969A
Application number: GB1511761.7A
Authority: GB
Inventors: Donna Davide; Meloni Michele
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2015-07-03
Filing date: 2015-07-03
Publication date: 2017-01-04
Also published as: GB201511761D0

Abstract

A fuel unit pump 180 for an internal combustion engine 110, comprising a pump flange 185 having a coupling surface 185a configured to be coupled to the internal combustion engine 110 and at least one through hole 185b for a fastener 3; a pump flange dampener 1 covering at least part of the coupling surface 185a ; decoupling sleeve 2 Inserted within the through hole 185b and configured to be interposed between the through hole 185b and the fastener 3. The arrangement of the dampener 1 and decoupling sleeve 2 is intended to reduce the level of transmitted vibration between the engine and the pump, and improve noise, vibration, and harshness (NVH) performance. The dampener 1 may be constructed of metallic wire mesh, while a further wire mesh tubular member (4, Fig. 6) may be located between the sleeve 2 and the through hole 185b.

Description

FUEL UNIT PUMP FOR AN INTERNAL COMBUSTION ENGINE TECHNICAL FIELD

The technical field relates to the coupling of a fuel unit pump to an internal combustion engine, and in particular to a fuel unit pump whose movements are decoupled from the internal combustion engine, and wherein vibrations between the pump and the engine are damped.

BACKGROUND

Internal combustion engines are provided with a fuel unit pump to provide fuel to the engine and in particular to the fuel injectors, usually via a fuel rail. The fuel unit pump is generally coupled directly to the engine. In particular, the fuel unit pump in generally coupled to the cylinder head or to the engine block. However, high loads and vibrations are transferred between the fuel unit pump and the engine. This results in an undesired sensible noise generation and also the performances of the fuel unit pump can be negatively affected as well by the vibrations.

It is thus an object of an embodiment of the present invention to provide a coupling between the internal combustion engine and the fuel unit pump causing low, or substantially absent, noise and vibrations, while allowing a secure coupling between the fuel unit pump and the engine.

It is a further object of an embodiment of the present invention, to provide such a coupling in a simple and cost effective manner.

SUMMARY

These and other objects are achieved by a fuel unit pump and by an internal combustion engine according to the independent claims. Further aspects/features of possible embodiments of the present invention are set out in the relative dependent claims.

According to an embodiment, a fuel unit pump for an internal combustion engine comprises a pump flange having a coupling surface configured to be coupled to the internal combustion engine and provided with at least one through hole for a fastener. The fuel unit pump also comprises a pump flange dampener covering at least part of the coupling surface of the pump flange, and a decoupling sleeve inserted within the through hole and configured to be interposed between the through hole and the fastener. As better disclosed later, the component referred as “decoupling sleeve” is so called because it allows decoupling of movements between the fuel unit pump and the fastener, so that loads and vibrations are not transmitted between the two elements and also between the fuel unit pump and the internal combustion engine to which the fasteners are connected.

The pump flange dampener allows damping the vibration transferred between the fuel unit pump and the internal combustion engine, such as for example the engine block or the cylinder head to which the fuel unit pump is coupled, through the pump flange.

Moreover, one or more festener are used to couple the fuel unit pump to the internal combustion engine. The fasteners, once the two elements are coupled, are constrained to the internal combustion engine, and thus they move (and, in particular, vibrate) together with the engine.

The presence of the decoupling sleeve allows to decouple the movements (and vibrations) of the fasteners from the fuel unit pump.

Direct contact between the fastener and the fuel unit pump, which would result in sensible noise, is also avoided.

The so-called “NVH” parameter (i.e. the evaluation of the Noise, Vibration, Harshness) of the fuel unit pump is thus improved. In fact, the flange dampener and the decoupling sleeve of the fuel unit pump cooperates to provide a decoupled joint between the fuel unit pump and the internal combustion engine.

According to an embodiment, the pump flange dampener is substantially flat. The relative positioning between the fuel unit pump and the internal combustion engine is thus substantially not affected by the presence of the pump flange dampener and at the same time an effective dampening of the vibrations at the pump flange can be obtained.

According to an embodiment, the pump flange dampener comprises a metallic wire mesh.

The metallic wire mesh provides for an effective dampening effect between the fuel unit pump and the internal combustion engine. In more detail, when the metallic wire mesh is compressed, the linked (for example knitted) wires of the wire mesh act as a spring, and a dampening effect is obtained due to friction. The metallic wire mesh also allows to withstand the high loads transmitted between the fuel unit pump and the internal combustion engine.

According to an embodiment, the decoupling sleeve comprises at least one flange extending outside the through hole.

This allows to easily position the decoupling sleeve within the through hole.

Moreover, a fastener is usually a screw provided with an elongated, and typically threaded, body protruding from a head. The elongated body is typically inserted within the through hole, while the head remains outside the through hole. A decoupling sleeve extending outside the through hole can thus prevent contact between the head of the fastener and the fuel unit pump.

According to an embodiment, the decoupling sleeve is coupled to the pump flange dampener.

This allows to simplify and to speed up the mounting of the pump flange dampener to the coupling surface of the pump flange of the fuel unit pump.

According to an embodiment, the pump flange dampener is provided with at least one opening for the decoupling sleeve. A portion of the decoupling sleeve can thus pass through pump flange dampener, allowing an improved coupling between the two elements. In particular the decoupling sleeve is configured to retain the pump flange dampener to the coupling surface of the pump flange.

According to an embodiment, the opening is provided with an at least partly deformable border.

As a result, the pump flange dampener can be quickly coupled to the decoupling sleeve, by inserting the decoupling sleeve In the opening, bending the relevant border.

According to an embodiment, a tubular metallic wire mesh is interposed between the decoupling sleeve and the through hole.

The tubular metallic wire cooperates with the decoupling sleeve to decouple the fastener from the fuel unit pump and to damp vibrations between the two elements. In particular, the decoupling sleeve allows to decouple movements between the fastener and the fuel unit pump, while the tubular metallic wire mesh provides for a vibration dampening effect.

According to an embodiment, the tubular metallic wire mesh has an height smaller than the height of the decoupling sleeve.

The tubular metallic wire mesh can thus be a simple, small and cost effective element. Mounting of a tubular metallic wire mesh having reduced height within the through hole is also simpler.

An embodiment of the present invention also provides for an internal combustion engine provided with a fuel unit pump according to any of the above mentioned aspects.

According to an embodiment, the internal combustion engine is provided with a plunger seat, wherein a plunger dampening element is interposed between the plunger of the fuel unit pump and the plunger seat.

The plunger dampening element provides for a decoupling between the plunger of the fuel unit pump and the plunger seat of the engine.

According to an embodiment, the plunger dampening element is annular.

In particular, according to an embodiment, the plunger dampening element has a substantially T-shaped section.

The above mentioned configurations provide for a small, simple and yet effective plunger dampening element.

According to an embodiment, the internal combustion engine comprises an engine block or a cylinder head, and the fuel unit pump is coupled to the engine block or to the cylinder head.

Coupling between the engine block or the cylinder head and the fuel unit pump according to one or more aspects above mention has proven to have good NVH (i.e., as previously mentioned “Noise, Vibration and Harshness") performances.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features advantages and details appear, by way of example only, in the following detailed description of embodiments, with reference to the accompanying drawings, in which: • Figure 1 shows a possible embodiment of an automotive system comprising an internal combustion engine; • Figure 2 is a cross-section according to the plane A-A of an internal combustion engine belonging to the automotive system of figure 1; • Figure 3 is a view of a possible coupling between an embodiment of a fuel unit pump and an internal combustion engine; • Figure 3a is an enlarged exploded view of a detail of figure 3; • Figure 4 is a schematic top view of a pump flange dampener of the fuel unit pump of figure 3; • Figures 5a and 5b are two possible embodiments of sleeve seats of the pump flange dampener of figure 3; • Figure 6 is an alternative embodiment of the fuel unit pump of figure 4; • Figure 7 is an enlarged view of an embodiment of a fuel unit pump, showing the coupling between a pump flange dampener and a decoupling sleeve; • Figure 8 is a schematic view of the knitted configuration of the wires of a wire mesh according to an embodiment of the present invention. • Figure 9 is a schematic perspective view of a fuel pump according to an embodiment of the present invention.

DETAILED DESCRIPTION

Exemplary embodiments will now be described with reference to the enclosed drawings without intent to limit application and uses.

Some embodiments may include an automotive system 100, as shown in Figures 1 and 2, that includes an internal combustion engine (ICE) 110 having an engine block 120 defining at least one cylinder 125 having a piston 140 coupled to rotate a crankshaft 145. A cylinder head 130 cooperates with the piston 140 to define a combustion chamber 150. A fuel and air mixture (not shown) is disposed in the combustion chamber 150 and ignited, resulting in hot expanding exhaust gasses causing reciprocal movement of the piston 140. The fuel is provided by at least one fuel injector 160 and the air through at least one intake port 210. The fuel is provided at high pressure to the fuel injector 160 from a fuel rail 170 in fluid communication with a high pressure fuel unit pump that increase the pressure of the fuel received from a fuel source 190. Each of the cylinders 125 has at least two valves 215, actuated by the camshaft 135 rotating in time with the crankshaft 145. The valves 215 selectively allow air into the combustion chamber 150 from the port 210 and alternately allow exhaust gases to exit through a port 220. In some examples, a cam phaser 155 may selectively vary the timing between the camshaft 135 and the crankshaft 145.

The air may be distributed to the air intake port(s) 210 through an intake manifold 200. An air intake duct 205 may provide air from the ambient environment to the intake manifold 200. In other embodiments, a throttle body 330 may be provided to regulate the flow of air into the manifold 200. In still other embodiments, a forced air system such as a turbocharger 230, having a compressor 240 rotationally coupled to a turbine 250, may be provided. Rotation of the compressor 240 increases the pressure and temperature of the air in the duct 205 and manifold 200. An intercooler 260 disposed in the duct 205 may reduce the temperature of the air. The turbine 250 rotates by receiving exhaust gases from an exhaust manifold 225 that directs exhaust gases from the exhaust ports 220 and through a series of vanes prior to expansion through the turbine 250. The exhaust gases exit the turbine 250 and are directed into an exhaust system 270. This example shows a variable geometry turbine (VGT) with a VGT actuator 290 arranged to move the vanes to alter the flow of the exhaust gases through the turbine 250. In other embodiments, the turbocharger 230 may be fixed geometry and/or include a waste gate.

The exhaust system 270 may include an exhaust pipe 275 having one or more exhaust aftertreatment devices 280. The aftertreatment devices may be any device configured to change the composition of the exhaust gases. Some exampies of aftertreatment devices 280 include, but are not limited to, catalytic converters (two and three way), oxidation catalysts, lean NOx traps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, and particulate filters. Other embodiments may include an exhaust gas recirculation (EGR) system 300 coupled between the exhaust manifold 225 and the intake manifold 200. The EGR system 300 may include an EGR cooler 310 to reduce the temperature of the exhaust gases in the EGR system 300. An EGR valve 320 regulates a flow of exhaust gases in the EGR system 300.

The automotive system 100 may further include an electronic control unit (ECU) 450 in communication with one or more sensors and/or devices associated with the ICE 110. The ECU 450 may receive input signals from various sensors configured to generate the signals in proportion to various physical parameters associated with the ICE 110. The sensors include, but are not limited to, a mass airflow and temperature sensor 340, a manifold pressure and temperature sensor 350, a combustion pressure sensor 360, coolant and oil temperature and level sensors 380, a fuel rail pressure sensor 400, a cam position sensor 410, a crank position sensor 420, exhaust pressure and temperature sensors 430, an EGR temperature sensor 440, and an accelerator pedal position sensor 445. Furthermore, the ECU 450 may generate output signals to various control devices that are arranged to control the operation of the ICE 110, including, but not limited to, the fuel unit pump 180, fuel injectors 160, the throttle body 330, the EGR Valve 320, the VGT actuator 290, and the cam phaser 155. Note, dashed lines are used to indicate communication between the ECU 450 and the various sensors and devices, but some are omitted for clarity.

Turning now to the ECU 450, this apparatus may include a digital central processing unit (CPU) in communication with a memory system 460, or data earner, and an interface bus. The CPU is configured to execute instructions stored as a program in the memory system, and send and receive signais to/from the interface bus. The memory system 460 may inciude various storage types including optical storage, magnetic storage, solid state storage, and other non-volatile memory. The interface bus may be configured to send, receive, and modulate analog and/or digital signals to/from the various sensors and control devices.

Instead of an ECU 450, the automotive system 100 may have a different type of processor to provide the electronic logic, e.g. an embedded controller, an onboard computer, or any processing module that might be deployed in the vehicle.

With reference to figure 3 (and as also visible in figure 9), the fuel unit pump 180 comprises a movable plunger 180d that is moved within the fuel unit pump 180, for drawing fuel from the fuel source 190 and for pressurizing it before the delivery to the fuel injector 160. In general the plunger 180d is moved by rotatable shaft of the internal combustion engine, for example by the camshaft 135.

The camshaft, as known, is provided with at least one drive cam. Due to the rotary movement of the camshaft 135, the cam alternatively engages and disengages the plunger 180d.

As a result, the rotation of the camshaft 135 can be transformed in a linear and reciprocating movement of the movable plunger 180d of the fuel unit pump 180.

The fuel unit pump 180 comprises a pump flange 185 to allow coupling with the internal combustion engine 110. In particular, the pump flange 185 is provided with a coupling surface 185a, configured to be coupled to an internal combustion engine 110.

In particular, the coupling surface 185a is shaped to match the shape of the portion of the internal combustion engine 110 to which it is meant to be coupled.

Typically, as per the shown embodiment, the coupling surface 185a is substantially flat.

At least part of the coupling surface 185a is covered by a pump flange dampener 1.

The pump flange dampener 1 is an element that allows dampening of the vibration transmitted between the fuel unit pump 180 and the internal combustion engine 110.

Preferably, the pump flange dampener 1 is substantially flat, in order to allow easy interposing between the internal combustion engine 110 and the coupling surface 185a of the pump flange 185 of the fuel unit pump 180.

In more detail, the pump flange dampener 1 is preferably shaped as a plate. In other words, the pump flange dampener 1 is preferably provided with a dimension that is sensibly inferior to the other two dimensions. In particular, the pump flange dampener 1 is typically provided with a reduced thickness, with respect to the other two dimensions.

In the shown embodiment, the pump flange dampener 1 is a metallic wire mesh. In more detail, the pump flange dampener 1 can comprise a plurality of metallic wires 10 knitted one to the other, for example to form a plurality of loops. A schematic view of metallic wires 10 is shown in figure 8. In particular, in figure 8 a simplified pianar knitted configuration is shown. In reality, the pump flange dampener 1 can comprise a plurality of superimposed layers (not shown), in order to have a thickness greater than the thickness of the single wire 10. Wires of different iayers can be also linked one to the others, according to known configurations.

In general, the wires 10 are connected with each other in order to provide dampening effect. As mentioned, the wires 10, when compressed, act as a spring, and provide for a dampening effect due to the friction between different wires 10.

The pump flange dampener 1 is preferably provided with an opening la, for the plunger 180d. In more detail, a plunger 180d typically protrudes from the coupling surface 185a. The opening la allows the plunger 180d to pass through the pump flange dampener 1. Preferably, the plunger 180d is surrounded by a plunger housing 180b, and the opening la substantially matches the outer shape of the plunger housing 180b.

In an embodiment, the pump flange dampener 1 comprises opening(s) 1b for a decoupling sleeve 2. The opening(s) 1b and the decoupling sleeve 2 will be better discussed later.

The pump flange 185 of the fuel unit pump 180 is also provided with one or more through holes 185b (i.e. a hole passing through the pump flange and extending between two substantially opposite surfaces of the pump flange) for relevant fasteners 3. In the shown embodiments, two fasteners 3 and two relevant through holes 185b are shown. Different number of through holes and fasteners can be provided in different embodiments, not shown. From now on, for easiness of description, reference to one through hole 185b and Its relevant fastener 3 (and decoupling sleeve 2, too) will be made.

Preferably, the through hole, at one extremity 181b, ends into the coupling surface 185a. At the opposite extremity 182b, preferably, the through hole 185b ends into a pump flange surface 185c (e.g. a pump flange external surface not coupled to the internal combustion engine), arranged opposite to, and distinct from, the coupling surface 185a.

The fuel unit pump 180 is also provided with a decoupling sleeve 2 configured to be inserted within the through hole 185b.

In one embodiment, the decoupling sleeve 2 Is shaped as a cylindrical, hollow element. Preferably, the diameter of the decoupling sleeve 2 is substantially coincident, and typically slightly smaller, than the diameter of the through hole 185b.

In one embodiment, the decoupling sleeve 2 extends outside the through hole 185b.

In the shown embodiment, the decoupling sleeve 2 is provided with two flanges 2a, 2b, extending outside the through hole 185b. In more detail, the decoupling sleeve 2 comprises a tubular body 2c. At the two ends of the tubular body 2c, the two flanges 2a, 2b protrude from the tubular body 2c. A flange 2a protrudes at one end of the tubular body 2c.

In an embodiment, shown in the figures, the flange 2a, in the undeformed condition, is arranged at least partly inclined with respect to the tubular body 2c. More in detail, considering the axis of the tubular body 2c, and a plane perpendicular to such an axis, at [east part of the flange 2a is angled with respect to such a plane. In other words, at least part of the flange 2a is arranged with an angle a greater than 0 degrees and smaller than 90 degrees with respect to a plane P perpendicular to the axis of the tubular body 2c.

In the shown embodiment, the angle a (measured between the plane P and the flange 2a, in the direction from the plane P towards the tubular body 2c) is less than 90 degrees. Preferably, as shown, such an angle a is less than 45 degrees. Thus, according to an embodiment, a portion of the tubular body 2c, too, protrudes outside the through hole 185b, i.e. a portion 20c of the tubular body 2c protrudes from the pump flange surface 185c.

The flange 2a is configured to be interposed between the fastener 3 and the pump flange surface 185c which, as mentioned, is typically opposite to the coupling surface 185a.

The tubular body 2c of the decoupling sleeve 2, thus, is configured substantially as a compression limiter, further provided with a flange 2a, integral with the tubular body 2c, acting as a conical spring washer. In other words, a conical washer (i.e. the flange 2a) is included in the compression limiter design (i.e. the tubular body 2c).

More in detail, the fastener 3 is generally provided with an elongate body 3a, protmding from a head 3b. The first flange 2a, in use, is thus preferably interposed between the head 3b of the fastener 3 and the pump flange surface 185c.

In an embodiment, when the head 3b of the fastener 3 is pressed against the pump flange surface 185c, the first flange 2a (and in particular its angled part) is deformed, according to its properties, to decouple the fastener 3 with respect to the pump flange 185.

The tubular body 2c decouples lateral movements of the fastener 3 from lateral movements of the fuel unit pump 180 (i.e. movements in a direction along plane P). The flange 2a decouples vertical movements of the fastener 3 from the vertical movements of the fuel unit pump 180 (i.e. movements along a direction perpendicular to plane P, i.e. parallel to the axis of the tubular body 2c).

In an embodiment, the decoupling sleeve 2 comprises a further flange 2b. The flange 2b Is placed at one end of the tubular body 2c of the decoupling sleeve 2 (opposite to the flange 2a). The flange 2b is coupled (directly or indirectly) with the coupling surface 185a of the fuel unit pump 180.

The flange 2b is engaged to the fuel unit pump 180 and it contacts the internal combustion engine 110, transmitting the load from the fastener 4 through the tubular body 2c.

When the fuel unit pump 180 is coupled to the internal combustion engine 110, the decoupling sleeve 2, and in particular the tubular body 2c, undergoes a slight elastic deformation, which is mainly axial.

Please note that, in figure 9, the flange 2a of a decoupling sleeve 2 is shown under the head 3b of a fastener and the flange 2b is shown in contact with the pump flange dampener 1 covering the coupling surface 185a.

In particular, in the shown embodiment, the flange 2b couples with the opening 1b, more precisely with the border 1c of the opening 1b, of the pump flange dampener 1, so that a portion (i.e. the border 1c) of the pump flange dampener 1 is interposed between the flange 2b and the coupling surface 185a.

As mentioned, in fact, the pump flange dampener 1 can be provided with openings 1b. In the shown embodiment, two openings 1 b are shown. Different number of openings 1b can be provided. One opening 1b will be now discussed, but the following description applies as well to the other openings 1 b possibly arranged on the pump flange dampener 1.

According to an embodiment, the opening 1b is defined by a deformable border 1c, e.g. that may have a reduced thickness with respect to the remaining portion of the pump flange dampener 1.

The border 1c can have different configurations. In the embodiment of figure 4, the border 1c is annular, i.e. it has a circular perimeter.

Alternative embodiments are shown in figures 5a and 5b. In these embodiments, the perimeter of border 1c is not circular. In more detail, the border 1c is provided with deformable flaps Id. Preferably, deformable flaps Id protrude internally with respect to an ideal circular perimeter 1e, which is shown in dashed lines in figures 4a and 4b. Outside the ideal circular perimeter 1e, the pump flange dampener 1 can be provided with a further portion of the deformable border 1c, e.g. a portion of the pump flange dampener 1 having reduced thickness with respect to the surrounding portion of the pump flange dampener 1. In alternative embodiments, the border 1c may be composed essentially by the flaps Id. As an example, the flaps Id may have a reduced thickness with respect to the portion of the pump flange dampener 1 surrounding the flaps Id, i.e. the portion of the pump flange dampener outside the ideal circular perimeter 1e.

It has to be noted that, in principle, all the pump flange dampener is “deformable” to properly operate (in particular it may be in general at least compressed). However, when it is made reference to a “deformable border” or to “deformable flaps” it is meant that these elements can be more easily deformed (in particularly bent) with respect to the other portion of the pump flange dampener 1.

In particular, the border 1c of the opening 1b is configured to bend when subject to a certain force, allowing insertion of the flange 2b of the decoupling sleeve within the opening 1b.

In more detail, the opening 1b has preferably a diameter slightly greater than the diameter of the tubular body 2c of the decoupling sleeve 2, but slightly smaller than the external diameter (or greater dimension) of the flange 2b. During mounting, the flange 2b is thus forced within the opening 1b, bending the border 1c (or at least the flaps Id of the border 1c). After the insertion of the flange 2b within the opening 1b, the border 1c (or at least the flaps Id of the border 1c) springs back in their original (i.e. unbent) position, so that the pump flange dampener 1, is retained by the border 1c itself.

Thus, as mentioned, in operating condition, at least part of the border 1c of the opening 1 b of the pump flange dampener 1 is interposed between the coupling surface 185a of the fuel unit pump and the flange 2b of the decoupling sleeve 2.

In general, according to an embodiment, the decoupling sleeve 2 is coupled to the pump flange dampener 1.

The decoupling sleeve 2 is preferably made of steel, or similar materials.

In different embodiments, the decoupling sleeve 2 can be provided with the flange 2a only, or with the flange 2b only. Alternatively, the decoupling sleeve 2 can be free from both the flanges 2a, 2b. As an example, it may be composed substantially by the tubular body 2c only.

With reference to figure 6, an alternative embodiment is shown.

In particular, in this embodiment, a wire mesh 4 is interposed between the decoupling sleeve 2 and the through hole 185b.

In more detail, the wire mesh 4 is interposed between the tubular body 2c of the decoupling sleeve 2 and the through hole 185b.

Preferably, the wire mesh 4 is a metallic wire mesh, having wires knitted one to the other, e.g. as per the configuration schematically shown in figure 8.

In order to be inserted within the through hole 185b, and in particular between the tubular body 2c of the decoupling sleeve 2 and the through hole 185b, the wire mesh 4 is preferably tubular as well.

As shown in the figures, the height of the tubular wire mesh 4 is preferably smaller than the height of the decoupling sleeve, i.e. of the tubular body 2c of the decoupling sleeve 2.

As a result, the tubular wire mesh 4 can be completely inserted within the through hole 185b, without protruding from it.

In figure 6, a further element providing decoupling between the fuel unit pump 185b and the internal combustion engine 110 is shown.

When the fuel unit pump 180 is coupled to the internal combustion engine, typically, the plunger 180d is partially inserted within the internal combustion engine 110. In other words, the internal combustion engine 110 is provided with a plunger seat 110a for the plunger 180d.

According to an embodiment, a plunger dampening element 5 is arranged between the plunger 180d and the plunger seat 110a.

In more detail, in the shown embodiment, the plunger 180d is provided with a plunger housing 180b, and the plunger dampening element 5 is arranged between the plunger housing 180b and the plunger seat 110a of the internal combustion engine 110.

Preferably, the plunger dampening element 5 is annular.

In the shown embodiment, the plunger dampening element 5 is provided with a T-shaped section. As a result, the plunger dampening element 5 is substantially configured as a T-shaped section 0-ring, or, more in general, as a T-shaped section gasket.

According to an embodiment, the plunger dampening element 5 is made of rubber.

For conciseness, the plunger dampening element 5 and the wire mesh 4 are shown together in figure 6 in a single embodiment. The two components are however independent one from the other, so that different embodiment may be provided with only one of the two components.

In the shown embodiment, the fuel unit pump 180 is mounted to the cylinder head 130 of the internal combustion engine. The fuel unit pump 180 can be mounted to different elements of the internal combustion engine 110. As an example, the fuel unit pump 180 can be mounted to the engine block 120.

During mounting, the decoupling sleeve 2 is inserted within the through hole 185b of the pump flange 185 and the pump flange dampener 1 is placed on the coupling surface 185a of the pump flange 185. Preferably, the decoupling sleeve 2 and the pump flange dampener 1 are coupled together, e.g. by deforming the border 1c of the opening 1b, as previously mentioned.

Possibly, a wire mesh 4 is placed between the decoupling sleeve 2 and the through hole 185b.

Subsequently, the fuel unit pump 180 is coupled to the internal combustion engine 110. In particular a fastener 3 is inserted w thin the through hole 185b, an coupled to a relevant fastener seat 110b of the internal combustion engine 110.

Typically, both the fastener 3 and the fastener seat 110b of the engine are threaded.

Possibly, a plunger dampening element 5 has been coupled to the internal combustion engine 110 or to the fuei unit pump 180 before coupling the first to the latter.

In use, the pump flange dampener 1 dampens the vibrations between the internal combustion engine 110 and the fuel unit pump 180.

The decoupling sleeve 2 decouples the movements of the fastener(s) 3 from the movement of the fuel unit pump 180. Possibly the tubular wire mesh 4 provides also a dampening effect between the fastener 3 and the fuel unit pump 180.

In particular as mentioned, the tubular body 2c of the decoupling sleeve 2 decouples lateral movements of the fastener 3 from lateral movements of the fuel unit pump 180, while the flange 2a decouples vertical movements of the fastener 3 from vertical movements of the fuel unit pump 180.

Preferably, the plunger dampening element 5 decouples the movement of the internal combustion engine 110 (in particular of the plunger seat 110a) from the movement of the plunger (in particular of the plunger housing 180b).

While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.

REFERENCE NUMBERS 1 pump flange dampener 1a opening of the pump flange dampener for the plunger of the fuel unit pump 1 b opening of the pump flange dampener for the decoupling sleeve 1c border of the opening 1b 1 d flaps of the border 1 c 1e ideal circular perimeter of the border 1c 2 decoupling sleeve 2a, 2b flanges of the decoupling sleeve 2c tubular body of the decoupling sleeve 3 fastener 3a elongated body of the fastener 3b head of the fastener 4 wire mesh 5 plunger dampening element 10 wire of the pump flange dampener 20c portion of the tubular body 100 automotive system 110 internal combustion engine (ICE) 110a plunger seat 110b fastener seat 120 engine block 125 cylinder 130 cylinder head 135 camshaft 140 piston 145 crankshaft 150 combustion chamber 155 cam phaser 160 fuel injector 170 fuel rail 180 fuel unit pump 180d plunger of the fuel unit pump 180b plunger housing 185 pump flange 185a coupling surface of the pump flange 185b through hole of the pump flange 185c pump flange surface 181b, 182b, ends of the through hole of the pump flange 190 fuel source 200 intake manifold 205 air intake duct 210 intake air port 215 valves of the cylinder 220 exhaust gas port 225 exhaust manifold 230 turbocharger 240 compressor 250 turbine 260 intercooler 270 exhaust system 275 exhaust pipe 280 exhaust aftertreatment device 290 VGT actuator 300 EGR system 310 EGR cooler 320 EGR valve 330 throttle body 340 mass airflow and temperature sensor 350 manifold pressure and temperature sensor 360 combustion pressure sensor 380 coolant and oil temperature and level sensors 400 fuel rail pressure sensor 410 cam position sensor 420 crank position sensor 430 exhaust pressure and temperature sensor 440 EGR temperature sensor 445 accelerator pedal position sensor 450 electronic control unit (ECU) 460 memory system

Claims

1. Fuel unit pump (180) for an internal combustion engine (110) comprising a pump flange (185) having a coupling surface (185a) configured to be coupled to the internal combustion engine (110) and at least one through hole (185b) for a fastener (3); the fuel unit pump further comprising a pump flange dampener (1) covering at least part of the coupling surface (185a) and a decoupling sleeve (2) inserted within the through hole (185b) and configured to be interposed between the through hole (185b) and the fastener (3).

2. Fuel unit pump (180) according to claim 1, wherein said pump flange dampener (1) is substantially flat.

3. Fuel unit pump (180) according to claim 1 or 2, wherein said pump flange dampener (1) comprises a metallic wire mesh.

4. Fuel unit pump (180) according to any of the preceding claims, wherein said decoupling sieeve (2) comprises at least one flange (2a, 2b) extending outside said through hole (185b).

5. Fuel unit pump (180) according to any of the preceding claims, wherein said decoupling sleeve (2) is coupled to said pump flange dampener (1).

6. Fuel unit pump (180) according to any claim 5, wherein the pump flange dampener (1) is provided with at least one opening (1b) for the decoupling sleeve (2).

7. Fuel unit pump (180) according to claim 6, wherein the opening (1b) is provided with an at least partly deformable border (1c).

8. Fuel unit pump (180) according to any of the preceding claims, wherein a tubular metallic wire mesh (4) is interposed between said decoupling sleeve (2) and said through hole (185b).

9. Fuel unit pump (180) according to claim 8, wherein the tubular metallic wire mesh (4) has an height smaller than the height of the decoupling sleeve (2).

10. Internal combustion (110) engine provided with a fuel unit pump (180) according to any of claims 1 to 9.

11. Internal combustion engine (110) according to claim 10, wherein the fuel unit pump (180) is provided with a plunger (180d), and the internal combustion engine (110) is provided with a plunger seat (180d), wherein a plunger dampening element (5) is interposed between the plunger (180d) and the plunger seat (185b).

12. Internal combustion engine (110) according to claim 11, wherein the plunger dampening element (5) is annular.

13. Internal combustion engine (110) according to claim 12, wherein the plunger dampening element (5) has a substantially T-shaped section.

14. Internal combustion engine (110) according to any claims 10 to 13, comprising an engine block (120) or a cylinder head (130), wherein the fuel unit pump (180) is coupled to the engine block (120) or to the cylinder head (130).