Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] The present disclosure relates generally to a cylinder head for an internal combustion engine for a motor diesel vehicle.
Background of the invention
[0002] Engineers are often looking for ways to reduce or eliminate combustion gas leakage around fuel injectors mounted in an engine. Combustion gas leakage is particularly problematic in the case of diesel type engines since the injector bores in the head of the engine open directly to the combustion space.

[0003] In the past, adequate sealing around the injectors has been accomplished through the use of a combination of malleable metallic (copper, brass, etc.) sleeves, elastomeric sealing washers and substantially large clamping forces pushing the individual injector into its bore in the engine.

[0004] Because of the necessary dimensional tolerancing of the injector's outer surface, injector bore in the engine and the malleable metallic sleeve, combustion gas leakage can still sometimes occur despite the relatively high clamping forces used to attach fuel injectors to a given engine.

[0005] In other words, combustion gas leakage can occasionally occur around one or more fuel injectors of an engine despite the fact that all of the fuel injector clamps have been torqued down with the same relatively high magnitude. In addition, engine vibrations and/or thermal loads can sometimes cause one or more injector clamping bolts to slightly loosen over an extended period of time, resulting in combustion gas leakage.

[0006] Conventional washer materials can typically not withstand the relatively high temperatures and cyclic pressures encountered near the tip of a fuel injector. Conventional sealing washer usually can only withstand temperatures up to about 300° F., and at the higher end of this scale the useful life of a given O-ring is relatively short.

[0007] In the existing embodiment, there is surface contact between injector bore seating surface and sealing washer. Depending on the surface roughness of this interface there is possibility of combustion gas leakage onto injector outer body surface.

[0008] Efforts have been made in the related prior art to provide different solutions for preventing the leakage and escape of combustion gases in internal combustion engines. For example, a US patent no. US 8813727 B2 provides a sealing assembly for a pressurized fuel feed system for an internal combustion engine. The seal assembly comprises providing a fuel conduit having a fluid flow passage therethrough for conveyance of a pressurized fuel-containing gas in a general fluid-flow direction with a first sealing surface disposed on the fuel conduit. A second sealing surface engages with the first sealing surface, such as to provide a fluid-tight connection preventing pressurized gas from leaving the fluid flow passage. The said first and second sealing surfaces are substantially perpendicular to the general fluid-flow direction. An O-ring is disposed between the first sealing surface and second sealing surface, the O-ring being compressed by the first and second sealing surfaces to form said fluid-tight connection. Preferably the O-ring is subjected to a squeeze of at least 40%, more preferably 50%, when the first and second sealing surfaces are coupled together. However, the invention in the prior art will not be able to prevent the escape of the combustion gases through the imperfections in the contact surface between the sealing surfaces.
Brief description of the accompanying drawings
[0009] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0010] Figure 1 illustrates a cylinder head (100) for an internal combustion engine for a motor diesel vehicle.

[0011] Figure 2 illustrates a magnified view of the cylinder head (100) for an internal combustion engine for a motor diesel vehicle showcasing the tapered surface (105).

Detailed description of the drawings
[0012] There is provided an internal combustion engine in which the cylinders (not shown) are covered by a cylinder head (100) and each cylinder is provided with a fuel injection device (200) and a combustion chamber (300), the combustion chamber (300) volume of each cylinder being formed predominantly in the associated piston (not shown). The fuel injection device (200) is situated in the side wall of the cylinder adjacent to the cylinder head (100). The portion of combustion chamber (300) formed in the piston is concentrated in one part of the crown of the piston so as to form extensive "squish" areas between the cooperating surfaces of the piston and the cylinder head (100). The cylinder head (100) is provided with a shield (not shown) projecting substantially in the axial direction within the cylinder on the side thereof opposite to the fuel injection device (200) and the said shield having an impingement surface facing towards the fuel injection device (200), and the fuel injection device (200) is arranged to direct a single compact jet of fuel, at a substantially zero angle of divergence, substantially perpendicularly to the said impingement surface, so that the impingement of the fuel jet on the said impingement surface causes fine atomization of the fuel.

[0013] The fuel injection device (100) comprises an injector body (not shown), and a nozzle body (not shown) that is positioned against the injector body such that a fuel inlet flow path (not shown) that is defined in the injector body is in alignment with a fuel inlet flow path (not shown) that is defined in the nozzle body (not shown). The alignment of the fuel inlet flow path that is defined in the injector body with the fuel inlet flow path that is defined in the nozzle body facilitates a flow of fuel from the fuel inlet flow path of the injector body to the fuel inlet flow path of the nozzle body. In one embodiment, during an assembly of the fuel inlet flow path that is defined in the injector body with the fuel inlet flow path that is defined in the nozzle body, a small clearance exists between the fuel inlet flow path that is defined in the injector body and the fuel inlet flow path that is defined in the nozzle body. The clearance that is defined between the fuel inlet flow path that is defined in the injector body and the fuel inlet flow path that is defined in the nozzle body facilitates for the flow of fuel that flows from the fuel inlet flow path that is defined in the injector body to the fuel inlet flow path that is defined in the nozzle body. From the clearance that is defined between the fuel inlet flow path that is defined in the injector body and the fuel inlet flow path that is defined in the nozzle body, the fuel flows to the outer periphery of the nozzle body.

[0014] Figure 1 illustrates a cylinder head (100) for an internal combustion engine for a motor vehicle. The cylinder head (100) has an injector bore (500) that accommodates the fuel injection device (200). The cylinder head (100), and in turn the nozzle of the fuel injection device (200), opens up into a combustion chamber (300). The fuel injection device (200) is affixed in position in the cylinder head (100) using a sealing washer (400). The sealing washer (400) where it meets the cylinder head (100) is denoted using a top surface end (405) and a bottom surface end (410) when the entire arrangement is held in assembly position as illustrated in Figure 2.

[0015] In the present embodiment, the cylinder head (100) meeting the bottom end (410) of the sealing washer (400) is tapered upwards such that the tapered end (105) of the cylinder head meets the tip of the bottom end (410) of the sealing washer (400). This arrangement of the present embodiment creates a line contact between the tapering surface (105) of the cylinder head (100) and the sealing washer (400). This tapering is enabled by shaving off the cylinder head using an angle end mill. The angle of tapering works and is enabled for the realization of the invention as long as the cylinder head top surface that meets the bottom end of the sealing washer is anything greater than 90 degrees. This tapering does not cause any issue with how the injector is seated in the cylinder head. The top surface of the sealing washer is flat enough to accommodate the nozzle retaining nut and therefore the injector seats properly. The sealing washer creates enough resistance to not make the injector spring up from the seating. The sealing washer deforms on the tapered surface thus comfortably holding the injector in place.

[0016] When combustion gas pressure builds up in the combustion chamber (300), the gas flowing upwards through the space available between the fuel injection device (200) body and the cylinder head (100), which is the available space in the injection bore (500), is therefore successfully arrested at the tapered point between the bottom end of the sealing washer (410) and the cylinder head (100). This, in turn, stops the leaked gas from flowing more upwards to the body of the fuel injection device (200). The leaked combustion gas, even though comes in direct contact with the washer and might have possible chances of eroding it, the washer can be easily replaced.

[0017] The arresting of the leaked combustion gas helps prolong the life of the fuel injection device (200) which would otherwise be susceptible to blackening and consecutively corrosion of the body of the fuel injection device (200) due to the extreme high temperature of the leaked combustion gas.

[0018] Thereby, the thermal load on the rest of the devices of the fuel injection system is also reduced. It also helps reduce power loss as well as avoid safety concerns, because in worst case combustion gas leakage can lead to safety issues like firing. With the life span of the fuel injection device (200) and in turn of the fuel injection system prolonged, there will be chances of fewer field complaints.
[0019] It must be understood that the embodiments explained in the above detailed description are only illustrative and do not limit the scope of this invention. Any modification to the cylinder head is envisaged and form a part of this invention. The scope of this invention is limited only by the claims.
, Claims:We Claim:
1. A cylinder head (100) for an internal combustion engine, in particular for a diesel engine, in particular for a motor vehicle, with at least one injector bore (500), which opens into at least one combustion chamber (300) of the combustion engine, for at least one fuel injection device (200), wherein the receiving injector bore (500) seats a sealing washer (400) to accommodate the fuel injection device (200), said sealing washer (400) having a top surface end point(405) and a bottom surface end point (410) when held in assembly position ,characterized in that there is further provided within the cylinder head (100) a tapering surface (105) that comes in contact with the sealing washer (400).

2. The cylinder head (100) as claimed in claim 1, wherein the tapering surface (105) of the cylinder head (400) tapers upwards to meet the bottom surface end point (410) of the sealing washer (400).

3. The cylinder head (100) as claimed in claim 1, wherein the tapering surface (105) of the cylinder head (100) comes in contact with the bottom surface end point (410) of the sealing washer (400).

4. The cylinder head (100) as claimed in claim 1, wherein the contact between the tapering surface (105) of the cylinder head (100) and the sealing washer (400) is a line contact.