GB2491148A

GB2491148A - Cylinder head with integral common rail fuel feed

Info

Publication number: GB2491148A
Application number: GB201108748A
Authority: GB
Inventors: Fiorello Losano
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2011-05-24
Filing date: 2011-05-24
Publication date: 2012-11-28
Anticipated expiration: 2031-05-24
Also published as: GB2491148B; GB201108748D0

Abstract

Disclosed is an internal combustion engine assembly comprising an engine block 120 defining a cylinder 125 and a cylinder head 130 fixed to the engine block 120. A common rail 170 is integrally formed in the cylinder head 130 and defines a fuel passage 175 arranged to convey fuel to a fuel injector 160 for the combustion chamber 150. The arrangement provides a single unit comprising the cylinder head 130 and common rail accumulator 170. A cooling fluid conduit 620 may be provided around the common rail 170 within the cylinder head 130. Casting techniques may be used in the manufacturing process.

Description

INTERNAL CCI4BUSTION ENGINE ASSEMBLY TEQiNIL FIflD The present disclosure relates to an internal combustion engine assembly.

Traditional diesel internal combustion engines have an engine block defining at least one cylinder having a piston coupled to rotate a crankshaft. A cylinder head cooperates with the piston to define a combustion chamber. A fuel and air mixture is disposed in the combustion chamber and ignited, resulting in hot expanding exhaust gasses causing reciprocal movement of the piston. The fuel is provided by at least one fuel injector and the air is provided through at least one intake port. The fuel is provided at high pressure to the fuel injector from a fuel rail in fluid corrmunication with a high pressure fuel pump that increases the pressure of the fuel received a fuel source.

These prior art engines comprise the fuel rail as an "add on" component, namely the rail is added externally with respect to the cylinder head and it is fixed to the cylinder head in a cantilevered position by means of a plurality of fixing means.

These known assemblies have a series of disadvantages, among which vibrations and noise can be mentioned.

Also, there is the need to have a series of components to hold the fuel rail, a situation that has a negative impact on costs and on engine packaging.

Furthermore, temperatures of the fuel can reach high values in some engine systems because of insufficient cooling with risks of lacques and of malfunctioning of the electronic parts of the injectors.

During the cold season, cold temperatures of the fuel, caused by the distance of the fuel rail with respect to the engine block, may negatively affect start up of the engine. Cold temperatures may also result in formation of paraffines in the fuel.

An object of an embodiment disclosed is to overcome the above mentioned drawbacks by means of a diesel engine rail assembly that has an improved performance in terms of noise and vibrations.

A further object is to provide a diesel engine rail assembly that has an improved thermal management.

Still another object of the present disclosure is to meet these goals by means of a simple, rational and inexpensive solution.

These objects are achieved by an engine assembly having the features recited in the independent claims.

The dependent claims delineate preferred and/or especially advantageous aspects.

StTh4RY An embodiment of the disclosure provides an internal combustion engine assembly, comprising an engine block defining a cylinder, a cylinder head fixed to the engine block and cooperating with the engine block to define a combustion chamber, and a fuel rail defining a fuel passage arranged to convey fuel to a fuel injector for the combustion chamber, wherein the cylinder head includes the fuel rail.

An advantage of this embodiment is that it reduces significantly vibrations and noise coming from the fuel rail.

According to a further embodiment of the invention, the fuel rail is integral with the cylinder head.

An advantage of this embodiment is that the overall layout of the engine system is more compact.

According to still another embodiment of the invention, the fuel passage is cast within the cylinder head.

An advantage of this embodiment is that total manufacturing costs are reduced since a less expensive material is used for casting the rail.

According to still another embodiment of the invention, a cooling fluid conduit is defined within the cylinder head.

An advantage of this embodiment is that it allows an appropriate arrangement for water cooling the when the engine is warm.

In another embodiment of the invention, one or more cooling fluid conduits are arranged proximal to the fuel rail.

In still another embodiment of the invention, the cooling fluid conduits surround the fuel rail.

According to another embodiment of the invention, the cooling fluid conduits are cast within the cylinder head.

Advantageously, this arrangement forms a thermal jacket around the fuel rail. In such a way, the fuel can be cooled by the water, or with other suitable cooling fluid, via the jacket when the engine is hot and can be warmed up to facilitate cold start, especially in combination with a thermal management unit for the ICE, namely a switchable water pump. Water is also hotter because it is warmed by the cylinder head.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows an automotive system; Figure 2 is a cross-section of an internal combustion engine belonging to the automotive system of figure 1; and Figure 3 shows a section view of a cylinder head for an internal combustion engine, according to an embodiment of the invention.

DEIIED DESCRIPIYION OF THE DRAWINGS

Preferred embodiments will now be described with reference to the enclosed drawings.

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. Injectors 160 in fig. 1 are represented in a purely schernatical way.

The fuel is provided at high pressure to the fuel injector 160 from a fuel rail 170 arranged integral with the cylinder head 130, not represented for simplicity in fig. 1 and better described with reference to fig. 3, in fluid communication with a high pressure fuel pump (not shown) that increases the pressure of the fuel received from a fuel source.

Fuel from the fuel rail 170 is conveyed to the injectors 160 in a conventional way, by means of tubes 179 that are each fixed to a respective joint 177 of the fuel rail 170 and that are external to the cylinder head 130. The joints 177 may be cast within the cylinder head 130.

Each of the cylinders 125 has at least two valves 215, actuated by a 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 VOT 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 examples of aftertreatment devices 280 include, but are not limited to, catalytic converters (two and three way), oxidation catalysts, lean NO traps, hydrocarbon adsorbers, selective catalytic reduction (5CR) 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 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 corrmunication 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.

More specifically, Figure 3 shows a section view of the cylinder head for an internal corrbustion engine 110, according to an embodiment of the invention, where the cylinder head 130 includes the fuel rail 170.

The fuel rail 170 includes a fuel passage 175 through which the pressurized fuel is conveyed to the fuel injectors 160.

In a preferred embodiment of the invention, the fuel rail 170 is integral with the cylinder head 130.

This means that in the casting mould for casting the cylinder head a suitable arrangement, for example by means of suitable inserts, is provided in order to obtain the fuel rail 170 sideways with respect to a main portion of the cylinder head 130 and integrated in the same mould.

Also, the fuel passage 175 is cast within the cylinder head 130.

Furthermore, at least a cooling fluid conduit 620 is integrated in the cylinder head 170 for cooling the fuel rail 170 when the engine is above a predetermined temperature.

In another errbodirnent of the invention, the asseirbly is equipped with a plurality of cooling fluid conduits 620 that are proximal to the fuel rail 170. Preferably, the cooling fluid conduits 620 surround the fuel rail 170, forming a cooling or thermal jacket 610.

The cooling fluid conduits 620 may be cast within the cylinder head 130.

A suitable cooling fluid may be water eventually with an antifreeze component.

An advantage of this embodiment is that it allows an appropriate channel for water cooling the fuel when the engine is warm.

In this way a more compact and economic engine design is obtained, with advantages also on engine cooling, in case of hot engine temperatures, and on fuel warming in case of cold temperatures.

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.

REFflEE NffiERS automotive system internal combustion engine (ICE) 120 engine block cylinder cylinder head camshaft piston 145 crankshaft combustion chamber cam phaser fuel injector fuel rail 175 fuel passage 177 joints 179 tubes 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 VOT 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 445 accelerator pedal position sensor 450 electronic control unit (ECU) 610 cooling jacket 620 cooling conduits cian

Claims

1. Internal combustion engine assembly, comprising an engine block (120) defining a cylinder (125), a cylinder head (130) fixed to the engine block (120) and cooperating with the engine block (120) to define a combustion chamber (150), and a fuel rail (170) defining a fuel passage (175) arranged to convey fuel to a fuel injector (160) for the combustion chamber (150), wherein the cylinder head (130) includes the fuel rail (170).

2. Internal combustion engine assembly as in claim 1, wherein the fuel rail (170) is integral with the cylinder head (130).

3. Internal combustion engine assembly as in claim 1, wherein the fuel passage (175) is cast within the cylinder head (130).

4. Internal combustion engine assembly as in claim 1, wherein a cooling fluid conduit (620) is defined within the cylinder head (130)

5. Internal combustion engine assembly as in claim 4, wherein one or more cooling fluid conduits (620) are arranged proximal to the fuel rail (170).

6. Internal combustion engine assembly as in claim 5, wherein the cooling fluid conduits (620) surround the fuel rail (170).

7. Internal combustion engine assembly as in claim 4, wherein the cooling fluid conduits (620) are cast within the cylinder head (130)