Abstract:
An internal combustion engine having fuel injection with a protrusion placed between a fuel injection nozzle and a spark plug in the combustion chamber. The protrusion shields the core nose of the spark plug, but not the gap between the center electrode and ground electrode of the spark plug. In this fashion, combustion is enhanced and carbon buildup on the porcelain body of the spark plug is prevented, thereby lessening the likelihood of a malfunction by the spark plug.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an internal combustion engine with a fuel spray deflector and more particularly to an internal combustion engine with a fuel injection system where the engine has an integrally formed fuel deflector that shields portions of a spark plug in the combustion chamber. 
     2. Description of the Related Art 
     It is well known that fuel deposited on the porcelain body portion of a spark plug located in a combustion chamber will cause the spark plug to short circuit and degrade engine operation. Fully functional spark plugs have longer lives, they provide for better engine fuel economy and they help reduce undesirable engine emissions. Nevertheless, it is desirable under certain operating conditions to directly inject fuel on the spark plugs so that more complete combustion occurs. This is especially true when the engine is at idle. 
     Prior attempts to shield portions of spark plugs in fuel injected engines have occurred. For example, it has been suggested that a rod may be inserted into a combustion chamber between the fuel injector nozzle and the spark plug to block fuel from portions of the spark plug. This arrangement offers a shield for the spark plug, however, the use of a rod requires extra engine parts, additional machining and increases the labor required for engine assembly. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The disadvantages mentioned above have been overcome by the present invention. What is described here is an engine having fuel injection comprising an engine block having a cylinder, a piston moveable in the cylinder, a cylinder head connected to the engine block, a cavity formed in the cylinder head aligned with the cylinder, a first opening in the cylinder head communicating with the cavity for receiving a fuel injector nozzle, a second opening in the cylinder head communicating with the cavity for receiving a spark plug, and a protrusion formed integrally with the cylinder head extending into the cavity and positioned between the first and the second openings and adapted to divert fuel injected by a fuel injector nozzle mounted in the first opening away from selected portions of a spark plug mounted in the second opening. 
     An object of the present invention is to provide a mechanism for shielding a spark plug in a fuel injected engine. Another aspect of the present invention is to provide such a shielding mechanism which is a simple and inexpensive. Yet another advantage of the present invention is to provide a spark plug shielding mechanism which does not increase the number of parts in an engine, does not require extra machining of the engine elements and does not require additional labor for assembling such an engine. 
    
    
     A more complete understanding of the present invention and other objects, aspects, aims and advantages thereof will be gained from a consideration of the following description of the preferred embodiment read in conjunction with the accompanied drawings provided herein. 
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a diagrammatic, elevational, sectional view of a portion of a fuel injection internal combustion engine. 
     FIG. 2 is an enlarged diagrammatic, elevational, sectional view of the upper portion of a combustion chamber of the engine shown in FIG.  1 . 
     FIG. 3 is a bottom plan view of the cylinder head shown in FIG.  2 . 
     FIG. 4 is a diagrammatic perspective view of a portion of the cavity of the cylinder head shown in FIGS. 2 and 3 between an opening for a fuel injector and an opening for a spark plug. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While the present invention is open to various modifications and alternative constructions, the preferred embodiment shown in the drawings will be described herein in detail. It is understood, however, that there is no intention to limit the invention to the particular form disclosed. On the contrary, the intention is to cover all modifications, equivalent structures and methods and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims. 
     Referring now to FIG. 1 there is shown a portion of an internal combustion engine  10  having direct fuel injection. The engine includes an engine block  12  and a cylinder head  14 . A cylinder  16  is formed in the engine block and a piston  18  is moveable in a reciprocating fashion within the cylinder. There is a cavity  20  formed in the cylinder head. The cavity forms with the region above the piston a combustion chamber. Mounted to the cylinder head and in communication with the cavity is a fuel injector  22  and a spark plug  24 . The construction and operation of fuel injection engines are known to those skilled in the art. For example the OMC Company of Waukegan, Ill. markets EVINRUDE and JOHNSON brand internal combustion engines with FICHT brand fuel injection technology. 
     Referring now to FIGS. 2 and 3 there is shown in more detail a portion of the internal combustion engine  10 . The cavity  20  is formed by an upper wall  30 , a curved side wall  32 , a flared ring wall  34  and a lateral ring wall  36 . Two openings are formed in the a cylinder head which open to the cavity. There is a first central opening  40  in the upper wall for receiving a nozzle  41  of the fuel injector  22  and a second side opening  42  in the curved side wall  32  for receiving a body portion of the spark plug  24 . 
     As is best shown in FIG. 2, the central and side openings  40  and  42  are arranged so that the fuel injector nozzle and the gap end of the spark plug are in close proximity to each other. This facilitates quick and relatively complete combustion, especially at low throttle, such as at engine idle. 
     The spark plug  24  has the usual construction, including a porcelain body, a core nose  44 , a central electrode  46 , a ground electrode  48  and a spark gap  50  formed between the central electrode and the ground electrode. 
     The nozzle  41  of the fuel injector is illustrated dispensing fuel in a spray configuration resembling a cone  52 . The operation and construction of a spark plug and of a fuel injector are known by those skilled in the respective arts. 
     To illustrate how simple and inexpensive a fuel deflector may be, reference is now made to FIGS. 2,  3  and  4 . Formed integral with the cylinder head is a protrusion in the form of a small ramp-like structure  60 . The protrusion includes a front wall  62 , two side walls  64  and  66  and a bottom wall  68 . The protrusion is cast or formed at the same time as the cylinder head, is made of the same material, typically aluminum, and is machined at the same time and in the same operations as those which form the two openings  40  and  42 . For example, the injector nozzle opening  40  is bored in the cylinder head and at the same time the front surface  62  of the protrusion may be machined. In a similar fashion, the machining of the second opening  42  may be used to machine the bottom surface  68  of the protrusion. It may now be appreciated that the cost of adding of the protrusion is marginal. There is no added parts requiring additional machining or increased engine assembly labor costs. 
     The geometry of the protrusion is such that most of the spark plug core nose is shielded by the protrusion from the fuel that is sprayed through the nozzle. This minimizes carbon build upon on the porcelain core nose of the spark plug. The width of the front surface  62  is generally the same as the diameter of the core nose  44 . 
     By shielding the spark plug, unwanted carbon deposits do not short the spark plug. Moreover, the gap  50  between the center electrode  46  and the ground electrode  48  is not shielded, and the spark or sparks that are generated by the spark plug during each power cycle will be within the cone of the fuel spray thereby facilitating fuel ignition. 
     In low speed, low load operation the nozzle injects fuel in a cone shaped pattern in the direction of the spark plug and the spark plug fires soon thereafter. The position of the protrusion is such as to shield the core nose of the spark plug from the fuel spray. However the spark plug gap is not shielded so that facilitated ignition may occur. 
     The specification above describes in detail an embodiment of the present invention. Other modifications and variations will under the doctrine of equivalents come within the scope of the appended claims. For example, making changes in width or geometry of the protrusion are considered equivalent structures. Also the location of the protrusion may be changed if the relationship between the nozzle opening and the spark plug opening in the cylinder head is changed. Still other alternatives will also be equivalent as will many new technologies. There is no desire or intention here to limit in any way the application of the doctrine of equivalents.