GB2531538A

GB2531538A - Internal Combustion Engine Comprising a fuel unit pump actuated by a camshaft

Info

Publication number: GB2531538A
Application number: GB1418672.0A
Authority: GB
Inventors: Lavazza Paolo
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2014-10-20
Filing date: 2014-10-20
Publication date: 2016-04-27
Also published as: GB201418672D0

Abstract

An internal combustion engine, eg a diesel engine, comprises a fuel unit pump 180 to supply a quantity of fuel to at least one fuel injector (160, fig.1), a rotatable camshaft 135 to actuate the fuel unit pump 180, and a lever 2 comprising a first contact surface 4 and a second contact surface 5. The first contact surface 4 of the lever 2 is coupled to the camshaft 135 and the second contact surface 5 of the lever is coupled to the fuel unit pump 180 to transmit the rotary movement of the camshaft 135 to the fuel unit pump 180, to actuate it. The fuel unit pump may comprise a plunger 10. The first and second contact surfaces 4, 5 may be on opposite sides (fig.3c), or on the same side (figs.3a, 3b), of the pivot centre (fulcrum) 3 of the lever 2.

Description

INTERNAL COMBUSTION ENGINE COMPRISING A FUEL UNIT PUMP ACTUATED

BY A CAMSHAFT

TECHNICAL FIELD

The technical field relates to the fuel injection of an internal combustion engine, and in particular to the actuation of a fuel unit pump via the rotating camshaft of the internal combustion engine.

BACKGROUND

According to a possible configuration of the internal combustion engine injection system, a fuel unit pump is provided in order to supply fuel under pressure to the fuel injectors (injector nozzle).

This injection system is used for example in high-pressure injection system of diesel internal combustion engine.

The fuel unit pump, a non-rotary pump which has a plunger moving longitudinally for creating a fluid pressure, is actuated by a correspondent cam lobe of the camshaft. More in detail, the fuel unit pump is provided with a movable plunger that is contacted by the camshaft, thus the rotary movement of the camshaft can be transmitted to the fuel unit pump, and in a particular to the plunger of the fuel unit pump contacted by the cam lobe of the camshaft.

In fact, the plunger is provided with a tappet roller that is contacted by the cam lobe of the camshaft, so that the rotary movement of the camshaft can be transformed in a linear movement of the movable plunger of the fuel unit pump. The fuel unit pump is connected to the fuel injectors, preferably by means of a fuel rail, to supply fuel in the engine cylinder.

However, to transmit the rotary movement of the camshaft to the fuel unit pump and in particular to its movable plunger, there is the need to arrange the fuel unit pump in direct contact with the camshaft.

More in detail, the plunger of the fuel unit pump needs to be arranged in contact with a cam lobe of the camshaft, to actuate the fuel unit pump.

This configuration inevitably generates constrains in the engine layout design, in fact, the fuel unit pump has to be arranged in a position where it contacts the camshaft. This negatively affects the flexibility in the components integration in the engine layout. In fact, some components of the engine, such as for example the gearbox, need to be repositioned in order to allow a correct positioning of the fuel unit pump in contact with the camshaft.

However, the repositioning of the engine components leads to undesired modifications of the engine layout and of its dimensions. In fact, actual developments in engine design and production aim at package restrictions leading to an overall reduction of the engine and components dimensions.

It is an object of an embodiment of the invention to allow the positioning of the fuel unit pump without restrictions. It is another object of an embodiment of the invention to increase the flexibility of the engine layout design and in particular to increase flexibility in the components positioning.

SUMMARY

These and other objects are achieved by an internal combustion engine comprising a lever, according to the independent claim. Further aspects of possible embodiments of the present invention are set out in the relative dependent claims.

An embodiment of the invention provides an internal combustion engine comprising a fuel unit pump, to supply a quantity of fuel to at least one fuel injector, and a rotatable camshaft to actuate the fuel unit pump. The engine comprises a lever that is coupled to the fuel unit pump and to the camshaft for receiving the rotary movement from the camshaft and to transmit the movement to the fuel unit pump, to actuate it.

The lever has a pivot center, acting as a fulcrum of the lever, and about which the lever can be pivoted. The lever comprises a first contact surface coupled to the camshaft, to receive the movement from the camshaft, and a second contact surface coupled to the fuel unit pump, to transmit the movement to the fuel unit pump. More in detail, the lever is coupled to the camshaft at the first contact surface and coupled to the fuel unit pump at the second contact surface. Thus, the rotary movement of the camshaft is transmitted to the fuel unit pump, to actuate it.

Advantageously, the lever, that is pivotable about the pivot center, allows to actuate the fuel unit pump by means of the rotation movement of the camshaft while increasing the flexibility in the engine layout design.

In fact, the use of a lever to actuate the fuel unit pump allows to increase flexibility in the positioning of the fuel unit pump which does not need to be in direct contact with the camshaft.

Additionally, the presence of the lever, coupled to the fuel unit pump and to the camshaft, allows to reduce loads exerted on the camshaft during the engine operation.

In fact, the lever allows to provide a fine tuning of the forces and loads acting between the camshaft and the fuel unit pump, thus allowing an accurate design the kinematics of the components.

Additionally, the lever, interposed between the camshaft and the fuel unit pump performs the function of a safety component, i.e. a component that is broken in case of engine failures. This allows to save other engine components in case of failure.

It has to be noted that according to possible embodiments, the fuel unit pump and/or the camshaft can be coupled to the correspondent contact surface of the lever, by contacting, directly or indirectly, the correspondent contact surface of the lever. In the case of direct contact, the fuel unit pump, or a part thereof, and/or the camshaft, or a part thereof, is in contact with the lever. In the case of indirect contact, one or more additional components can be interposed between the fuel unit pump and/or the camshaft and the correspondent contact surface of the lever.

According to different embodiments, intended to advantageously increase the positioning of the engine components, and in particular of the fuel unit pump, the pivot center of the lever is arranged between the fuel unit pump and the camshaft, or the camshaft is arranged between the pivot center and the fuel unit pump, or the fuel unit pump is arranged between the pivot center and the camshaft.

In other words, according to possible embodiments, the pivot center is arranged on the lever between the first contact surface coupled to the camshaft and the second contact surface coupled to the fuel unit pump, or the first contact surface coupled to the camshaft is arranged on the lever between the pivot center and the second contact surface coupled to the fuel unit pump, or the second contact surface coupled to the fuel unit pump is arranged on the lever between the first contact surface coupled to the camshaft and the pivot center of the lever.

These and other configurations of the pivot center of the lever with respect to the second contact surface for the fuel unit pump and the first contact surface for the camshaft, allows to increase flexibility of the possible engine layout and in a particular the position of the fuel unit pump, thus avoiding interference with the space provided for other engine components. To this regard, according to a possible embodiment, the pivot center of the lever is arranged substantially at one end of the lever. However, according to another possible embodiment, the pivot center of the lever is arranged substantially at a central portion of the lever.

According to still another embodiment, the pivot center of the lever is constrained to the engine block of the internal combustion engine. This embodiment advantageously allows to provide an easy connection of the lever to a fix part.

According to another embodiment, the pivot center of the lever is parallel to the rotation axis of the camshaft. In this embodiment, the rotary movement of the camshaft can be easily and effectively transmitted to the fuel unit pump by the pivoting movement of the lever about the pivot center, to actuate the fuel unit pump.

According to a possible embodiment, the fuel unit pump and the lever are coupled with at least part of the fuel unit pump contacting, or constrained to, the second contact surface of the lever. Preferably the fuel unit pump comprises a movable plunger and the fuel unit pump is arranged with the movable plunger contacting, or constrained to, the second contact surface of the lever. In other words, the second contact surface of the lever is coupled to the fuel unit pump with the movable plunger contacting the second contact surface of the lever.

According to still another embodiment, the camshaft and the lever are coupled with at least part of the camshaft contacting the first contact surface of the lever. Preferably the camshaft comprises at least one cam lobe, and the camshaft is arranged with the at least one cam lobe contacting the first contact surface of the lever. In other words, the first contact surface of the lever is coupled to the camshaft with the at least one cam lobe contacting the first contact surface of the lever.

Advantageously, according to these embodiments, the lever can be easily arranged in an internal combustion engine to actuate the fuel unit pump by the rotatable camshaft without modification of these components. In fact, the lever can be arranged to contact a cam lobe of the camshaft and a movable plunger of the fuel unit pump, and in particular a tappet roller connected to the movable plunger.

According to an embodiment of the invention, the pivot center of the lever is fixed, thus allowing the actuation of the fuel unit pump by the pivoting moment of the lever about the pivot center, caused by the rotation of the camshaft.

According to a possible embodiment, the lever comprises a through hole, preferably passing through said lever. The pivot center of the lever corresponds to (is defined by) the through hole. An advantage of this embodiment is to reduce complexity of the manufacture process of the lever and also to provide an easy mode of connection of the lever to a fix part of the engine, while allowing the pivot movement of the lever.

According to a possible embodiment, the second contact surface coupled to the fuel unit pump and/or the first contact surface coupled to the camshaft is, at least in part, substantially flat, or at least in part, substantially curved.

Advantageously, the shape of the lever, and in particular of the surfaces intended to couple the lever to the fuel unit pump and to the camshaft can be shaped with different shapes. The curved, or flat, shapes of the first and second contact surfaces of the lever allows to effectively transmit the rotary movement of the camshaft to the fuel unit pump, so as to actuate it.

The shape of the lever also allows to reduce frictions and to better distribute loads and forces during the engine operation.

BRIEF DESCRIPTION OF THE DRAWINGS

Other feature, 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; * Figures 3a, 3b and 3c, schematicaNy show three possible embodiments of the lever and its arrangement with respect to the fuel unit pump and the camshaft; * Figures 4 and 5 are two partial section views of an internal combustion engine wherein a lever is arranged between the fuel unit pump and the camshaft. 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 pump that increase the pressure of the fuel received from a fuel source 190. According to a possible embodiment, the engine comprises a fuel unit pump 180 that is actuated by the rotation of a camshaft 135. 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 2 0 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 examples 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 (please let us know if other sensors for the fuel unit pump are provided), 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, or data carrier 460, and an interface bus. The CPU is configured to execute instructions stored as a program in the memory system, and send and receive signals to/from the interface bus. The memory system may include 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.

The program stored in the memory system is transmitted from outside via a cable or in a wireless fashion. Outside the automotive system 100 it is normally visible as a computer program product, which is also called computer readable medium or machine readable medium in the art, and which should be understood to be a computer program code residing on a carrier, said carrier being transitory or non-transitory in nature with the consequence that the computer program product can be regarded to be transitory or non-transitory in nature.

An example of a transitory computer program product is a signal, e.g. an electromagnetic signal such as an optical signal, which is a transitory carrier for the computer program code. Carrying such computer program code can be achieved by modulating the signal by a conventional modulation technique such as QPSK for digital data, such that binary data representing said computer program code is impressed on the transitory electromagnetic signal. Such signals are e.g. made use of when transmitting computer program code in a wireless fashion via a Wi-Fi connection to a laptop.

In case of a non-transitory computer program product the computer program code is embodied in a tangible storage medium. The storage medium is then the non-transitory carrier mentioned above, such that the computer program code is permanently or non-permanently stored in a retrievable way in or on this storage medium. The storage medium can be of conventional type known in computer technology such as a flash 2 5 memory, an Asic, a CD or the like.

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.

Returning on the fuel injection, according to a possible embodiment, the internal combustion engine 110 is provided with a fuel unit pump 180 connected to a fuel source 190, from which the fuel is provided. The fuel unit pump 180 is connected to one or more fuel injectors 160 (injector nozzle), preferably by a fuel rail 170.

As better shown in figures 3a, 3b, 3c, 4 and 5, according to a possible embodiment, the fuel unit pump 180 comprises a movable plunger 10 that is moved, preferably along a linear pumping movement S inside the body of the fuel unit pump, for drawing fuel from the fuel source and for pressurizing it before the delivery to the fuel injector 160.

More in detail, the fuel is supplied to the fuel injector 160 from the fuel unit pump 180 due to a pumping movement S of the plunger 10. In fact, the plunger 10 is movable between a non-operative position, in which it is extracted from the body of the fuel unit pump, or from a chamber provided therein, and an, operative position in which it is moved inside the body of the fuel unit pump (as schematically shown in figures 3a, 3b, 3c, 4 and 5 by arrow S). Returning means, such as for example a spring 11, are provided to maintain the movable plunger 10 in the non-operative position.

The movable plunger 10 of the fuel unit pump is actuated to reach the operative position, by means of the camshaft 135, and in particular by at least one cam lobe 135a of the camshaft, as for example schematically shown in figures 3a, 3b, 3c, 4 and 5. The fuel unit pump 180 can be further provided with a tappet roller 12, connected to the movable plunger 10, to easily actuate the fuel unit pump.

According to a possible embodiment of the invention, a lever 2 is provided in the internal combustion engine 110 to actuate the fuel unit pump 180 by the rotatable camshaft 135.

The lever 2 comprises a pivot center 3, about which the lever can be pivoted. It has to be noted that the term "lever is used in the present disclosure to indicate a substantially rigid body, preferably an elongated rigid body extending along an axis X, or line, having a pivot center 3 about which the lever can be pivoted. The lever 2 is able to convey (transmit) movements between two or more components coupled to the lever 2, preferably in correspondence of two contact surfaces 4, 5 of the lever 2, i.e. a first contact surface 4 and a second contact surface 5 of the lever 2. It has to be understood that the components coupled to the lever 2 can be contacted by the lever, or can be constrained to it.

It has to be further noted that the term "contact surface" is used in the present disclosure to indicate a portion, or an area, of the lever, intended to receive and/or transmit forces, and thus movements, between the lever and a component that is coupled (in contact, or constrained) to the lever. The lever 2 comprises a first contact surface 4 that is coupled to the camshaft 135, for receiving the movement from the camshaft, and a second contact surface 5 coupled to the fuel unit pump 180, to transmit the movement to it. More in detail, according to an embodiment of the invention, the lever 2 is arranged to contact the camshaft 135 and the fuel unit pump 180.

As already mentioned above, the contact between the fuel unit pump and/or the camshaft with the lever can be direct, or indirect, i.e. with the interposition of one or more additional components. According to possible embodiments, as for example shown in the figures, a direct contact of these components is used.

The fuel unit pump 180 and the lever 2 are arranged with at least part of the fuel unit pump 180 contacting a portion of the lever 2, and in particular contacting the second contact surface 5 of the lever 2. As mentioned above, according to a possible embodiment, the fuel unit pump 180 comprises a movable plunger 10, which can be provided with a tappet roller 12. The fuel unit pump 180 is coupled to the lever 2 with the movable plunger 10, and eventually with the tappet roller 12, contacting the second contact surface 5 of the lever 2.

According to an embodiment, not shown in the figures, the fuel unit pump can be constrained to the lever in correspondence of the second contact surface 5, for example with the movable plunger hinged to the lever.

Additionally, also the camshaft 135 is coupled to the lever 2 with at least part of the camshaft 135 contacting the lever 2, preferably in correspondence of the first contact surface 4 of the lever 2. As mentioned above, according to a possible embodiment, the camshaft 135 comprises at least one cam lobe 135a, and the camshaft 135 and the lever 2 are coupled with the at least one cam lobe 135a contacting the first contact surface 4 of the lever 2.

With the lever 2 contacting the cam lobe 135a and the movable plunger 10 of the fuel unit pump 180, the rotary movement of the camshaft 135 can be transmitted, preferably as a linear movement, to the fuel unit pump 180 and used to actuate it.

In other words, the pivot movement R of the lever 2 about the pivot center 3 is used to convey the rotary movement of the camshaft 135, about its rotation axis 135c, to the fuel unit pump 180.

2 0 More in detail, the cam lobe 135a contacts the lever 2, in correspondence of the first contact surface 4, and causes the movement S of the plunger 10. In fact, due to the contact of the lever 2 with the cam lobe 135a, the movable plunger 10 coupled to the lever 2 can be moved from the non-operative position to the operative position, in which the fuel unit pump supplies fuel to the injector 160.

It has to be noted that, according to possible embodiments, the shape of the cam lobe 135a intended to actuate the fuel unit pump 180 can be different, for example from those shown in figures 3a, 3b, 3c, 4 and 5. In fact, the shape of the cam lobe 135a can be designed to actuate the fuel unit pump by providing one or more activations (i.e. movements of the plunger 10 in the operative position) of the fuel unit pump 180 during a complete rotation of the camshaft 135.

In particular, according to a possible embodiment, the fuel unit pump 180 is actuated in order to move the movable plunger 10 in the operative position, in which the fuel unit pump is activated and supplies fuel to the injector 160, when the nose 135b of the cam lobe 135a, i.e. when the farthest portion of the cam lobe 135a, from the rotation axis 135c of the camshaft 135, contacts the lever 2. One or more cam nose 135b can be provided to activate the fuel unit pump 180 during a complete rotation of the camshaft 135 about the rotation axis 135c.

According to other possible embodiments, different relative arrangements of the lever 2, of the fuel unit pump 180 and of the camshaft 135, and in particular of the cam lobe 135a can be provided.

According to a first possible embodiment, as for example shown in figures 1 and 4, the camshaft 135 is arranged between the pivot center 3 and the fuel unit pump 180. In other words, the first contact surface 4 coupled to the camshaft 135 is arranged on the lever 2 between the pivot center 3 and the second contact surface 5 coupled to the fuel unit pump 180. More in detail, the pivot center 3 is arranged substantially at an end of the lever 2 and the camshaft 135, and in particular the cam lobe 135a, is arranged closer to the pivot center 3 than the fuel unit pump 180, along the extension of the lever 2.

This configuration, as also visible in figure 4, allows to increase the stroke (movement S) of the movable plunger of the fuel unit pump 180.

According to another possible embodiment, as shown for example in figures 3b and 5, the fuel unit pump 180 is arranged between the pivot center 3 and the camshaft 135. In other words, the second contact surface 5 coupled to the fuel unit pump 180 is arranged on the lever 2 between the first contact surface 4 coupled to the camshaft 135 and the pivot center 3. More in detail, the pivot center 3 is arranged substantially at one end of the lever 2 and the fuel unit pump 180 is arranged closer to the pivot center 3 than the camshaft 135, along the extension of the lever 2.

This configuration allows to minimize the loads exerted on the camshaft 135 during the actuation of the fuel unit pump 180.

According to a further possible embodiment, as for example shown in figure 3c, the pivot center 3 of the lever 2 is arranged between the fuel unit pump 180 and the camshaft 135, In other words, the pivot center 3 is arranged on the lever 2 between the first contact surface 4 coupled to the camshaft 135 and the second contact surface 5 coupled to the fuel unit pump 180.

Summarizing, according to possible embodiments, the pivot center can be arranged substantially at a central (middle) portion of the lever 2, with the fuel unit pump 180 and the camshaft 135 arranged on two opposite sides, with respect to the pivot center, along the axis X of the lever 2.

According to other possible configurations, the pivot center 3 can be arranged substantially at one end of the lever 2 and the fuel unit pump 180, or the camshaft 135, is arranged closer to the pivot center 3 than the other. It has to be noted that the distance of the fuel unit pump 180 and of the camshaft 135 from the pivot center 3 are selected in order to actuate the fuel unit pump by the camshaft, while controlling loads transmission between these components during the engine operation.

As mentioned above, the lever 2 comprises a substantially elongated body, having an axis X, or a line, along which it extends. The fuel unit pump 180 and the camshaft 135 can be arranged on the same side or at two opposite sides 2a, 2b of the lever with respect to its axis, or extension line.

In other words, the first and second contact surfaces 4, 5 coupled to the camshaft 135 and to the fuel unit pump 180 are arranged on two opposite sides 2a, 2b of the lever 2, with respect to the axis X, or line, along which the lever 2 extends. For example, in the embodiment shown in figures 3a, 3b, 4 and 5, the fuel unit pump 180 and the camshaft 135 are arranged on two opposite sides 2a, 2b of the lever 2. In the embodiment shown in figure 3c, the fuel unit pump 180 and the camshaft 135 are arranged in correspondence of the same side 2b of the lever 2, i.e. the lower side 2b in figure 3c.

According to a possible embodiment, the pivot center 3 of the lever 2 is fixed. The pivot center 3 can be constrained to a fix component, preferably a component of the engine 110. As for example shown in figure 5, the pivot center 3 of the lever 2 is constrained to the engine block 120 of the internal combustion engine 110.

Even if not shown in the attached figures, suitable constraining means of the lever 2 can be used, such as for example, pins, blots, etc., provided that the lever 2 can pivot about the pivot center 3.

According to a possible embodiment, the pivot center 3 of the lever 2 is parallel to the rotation axis 135c of the camshaft 135. In other words, the pivot axis defined by the pivot center 3 of the lever 2 is parallel to the rotation axis 135c of the camshaft.

Therefore, the contact of the camshaft 135 and in particular of cam lobe 135a with the lever allows a rotation of the lever 2 about the pivot center 3.

According to a possible embodiment, the pivot center 3 of the lever 2 comprises a through hole. In other words, the pivot center 3 is defined by a hole passing through the lever body. In this case, the pivoting axis of the lever can be correspondent to the axis of 2 5 the through hole.

It has to be noted that the pivot center 3, and in particular the pivot axis of the lever 2, can be substantially perpendicular to the axis X, along which the lever 2 extends.

According to a possible embodiment, as for example shown in figures 4 and 5, the first contact surface 4 coupled to the camshaft 135 is, at least in part, substantially curved and the second contact surface 5 coupled to the fuel unit pump 180 is, at least in part, substantially flat.

This configuration allows to better conveys the rotary motion of the camshaft 135 to the fuel unit pump 180, while reducing the loads transmitted.

It has to be noted that different shapes and configurations of the first and second contact surfaces 4, 5 of the lever 2 can be provided.

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

2 Lever 2a Side of the lever 2b Side of the lever 3 Pivot Center 4 First Contact Surface 5 Second Contact Surface Plunger 11 Spring 12 Tappet Roller R Rotation directions of the lever X Lever axis S Plunger movement automotive system internal combustion engine (ICE) 120 engine block 125 cylinder cylinder head 135 camshaft 135a cam lobe 135b cam lobe nose 135c camshaft rotation axis piston crankshaft combustion chamber cam phaser 160 fuel injector fuel rail fuel unit pump 190 fuel source intake manifold 205 air intake dud 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)

Claims

CLAIMS1. An internal combustion engine (110) comprising a fuel unit pump (180) to supply a quantity of fuel to at least one fuel injector (160), a rotatable camshaft (135) to actuate said fuel unit pump (180), and a lever (2) comprising a first contact surface (4) and a second contact surface (5), wherein said first contact surface (4) of the lever (2) is coupled to the camshaft (135) and said second contact surface (5) of the lever (2) is coupled to the fuel unit pump (180), to transmit the rotary movement of the camshaft (135) to the fuel unit pump (180), to actuate it.
2. The internal combustion engine according to claim 1, wherein the fuel unit pump (180) comprises a movable plunger (10), the second contact surface (5) of the lever being coupled to the fuel unit pump (180) with the movable plunger (10) contacting the second contact surface (5) of the lever (2).
3. The internal combustion engine according to claim 1 or 2, wherein the camshaft (135) comprises at least one cam lobe (135a), the first contact surface (4) of the lever (2) being coupled to the camshaft (135) with the at least one cam lobe (135a) contacting the first contact surface (4) of the lever (2).
4. The internal combustion engine according to any previous claim, wherein the lever (2) extends along an axis (X), and said first and second contact surfaces (4, 5) of 1the lever are arranged on the same side (2a, 2b) of the lever with respect to said axis (X) of the lever (2), or are arranged on two opposite sides (2a, 2b) of the lever (2), with respect to said axis (X) of the lever (2).
5. The internal combustion engine according to any previous claim, wherein the pivot center (3) of the lever is arranged substantially at one end of the lever (2).
6. The internal combustion engine according to any claim 1 to 5, wherein the first contact surface (4) coupled to the camshaft (135) is arranged between the pivot center (3) of the lever (2) and the second contact surface (5) coupled to the fuel unit pump (180).
7. The internal combustion engine according to any claim 1 to 5, wherein the second contact surface (5) coupled to the fuel unit pump (180) is arranged between the first contact surface (4) coupled to the camshaft (135) and the pivot center (3) of the lever (2).
8. The internal combustion engine according to any claim 1 to 4, wherein the pivot center (3) of the lever (2) is arranged between the first contact surface (4) coupled to the camshaft (135) and the second contact surface (5) coupled to the fuel unit pump (180).
9. The internal combustion engine according to any previous claim, wherein said lever (2) comprises a fixed pivot center (3).
10. The internal combustion engine according to any previous claim, wherein said lever (2) comprises a through hole, the pivot center (3) of the lever (2) corresponding to said through hole.
11. The internal combustion engine according to any previous claim, further comprising an engine block (120), the pivot center (3) of said lever (2) being constrained to said engine block (120).
12. The internal combustion engine according to any previous claim, wherein the pivot center (3) of the lever (2) is parallel to the rotation axis (135c) of the camshaft (135).
13. The internal combustion engine according to any previous claim, wherein the second contact surface (5) coupled to the fuel unit pump (180) and/or the first contact surface (4) coupled to the camshaft (135) is, at least in part, substantially flat.
14. The internal combustion engine according to any previous claim, wherein the second contact surface (5) coupled to the fuel unit pump (180) and/or the first contact surface (4) coupled to the camshaft (135) is, at least in part, substantially curved.