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 plus 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 Figure 1 is a diagrammatic, elevational, sectional view of a portion of a fuel injection internal combustion engine.

Figure 2 is an enlarged diagrammatic, elevational, sectional view of the upper portion of a combustion chamber of the engine shown in Figure 1.

Figure 3 is a bottom plan view of the cylinder head shown in Figure 2.

Figure 4 is a diagrammatic perspective view of a portion of the cavity of the cylinder head shown in Figures 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 Figure 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 220 formed in 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, Illinois markets EVINRUDE and JOHNSON brand internal combustion engines with FICHT brand fuel injection technology.

Referring now to Figures 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 Figure 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 Figures 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 consider 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.