Combustion chamber drain system
INTRODUCTION 
     The present invention relates to submersible outboard engines and in particular to a combustion chamber drain system for quickly and completely purging seawater from said chamber. 
     BACKGROUND OF THE INVENTION 
     Submersible engines presently in use intake seawater by various means. Quick and virtually complete elimination of such water from the engine combustion chamber is obviously highly desirable to preserve engine performance and structural integrity. Most important in military and emergency applications is the need to return the engine to full operational condition at the earliest possible time. Presently, submersible engines remove entrapped water from their combustion chambers by forcing the water past the piston rings. This is a time consuming process that can be damaging to the pistons, the piston rings, and the connecting rods. The degree to which entrapped water removal is successful is always in question when removal is dependent upon the water being forced past the piston rings. 
     SUMMARY OF THE INVENTION 
     It is thus an object of the present invention to provide a system for fast and complete removal of seawater entrapped in a submersible outboard engine. 
     It is yet an another object of the present invention to provide a system for removing entrapped seawater from the combustion chamber of a submersible outboard engine without the seawater having to be moved passed the piston rings. 
     It is still another object of the present invention to provide a system for elimination of entrapped seawater from the combustion chamber of a submersible outboard engine through a quick-release high pressure drain valve connected to a port in the engine cylinder head. 
     It is finally another object of the present invention to provide a system for elimination of entrapped seawater from the combustion chamber of a submersible outboard engine through a quick-release poppet-like valve. 
     These and other objects, features, and advantages will be more clearly understood when the following detailed description is considered in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view of the invention. 
     FIG. 2 is an exploded view of the poppet valve used in the invention. 
     FIG. 3 is a side view of the assembled poppet valve. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, the present invention, the combustion chamber drain system 10 consists of the modified cylinder head 14 which has the spark plug or ignition source port 17, the poppet valve boss 18, the drain valve 22, and the combustion chamber portion 26. 
     The modified cylinder head 14 connects by means of bolts (not shown) to the engine block 30 so that the combustion chamber portion 26 of the head 14 mates with the combustion chamber portion 38 of the engine block 30. The piston 34 is encircled by the piston rings 36 for sealing the piston 34 to the wall 40 of the combustion chamber. 
     The drain valve 22 is a high pressure poppet style valve. See FIGS. 2 and 3. In FIG. 2, the drain valve 22 is shown consisting of the valve body 42 which receives the poppet 46. The &#34;O&#34; ring 50 sits in the &#34;O&#34; ring groove or neck 67 in the end cap 70. It seals the valve body 42 to the cylinder head 14. The valve body 42 has a lapped seal 43 to the surface 45 of the poppet 46. The valve body 42 contains the symmetrically spaced discharge ports 44 about its circumference. Upon insertion of the poppet 46 into the valve body 42, the spring 54 is caused to encircle the poppet 46 and compressed by the piston 58 which engages the threaded end of the poppet 46. The piston 58 has the &#34;U&#34;-shaped one-way low pressure packing seal 62 encircling it about the intermediate neck 64. The &#34;O&#34; ring 66 encircles the end cap 70 about the neck 67. The end cap 70 engages the hexhead end 61 of the piston 58 which engages and compresses the spring 54 into the cavity 45 in the valve body 42. The end cap 70 is then secured to the valve body 42 by means of the cap screws 74, shown in FIG. 3, extending through the end cap 70, through the lock washers 78, and into the valve body 42. The pressure range for poppet valve selection is, of course, related to the performance specifications of the engine with which it is to be used. The &#34;O&#34; ring seals are selected for engine temperature and automotive or marine environments. 
     During actual use the high pressure poppet style drain valve 22 is threaded into the modified cylinder head 14. Assuming the engine is submerged and the combustion chambers take on water, the combustion chamber drain system 10 can be operated as soon as the engine emerges from and remains above the water surface. A compressed-air nipple 81 is threaded into the air port 82 and compressed air is introduced to force the piston 58 against the spring 54 overcoming the force it maintains to keep the poppet 46 seated at the lapped seal 43. This causes the poppet to move away from its seat sealing the valve body 42 from the engine combustion chamber portion 26. Once the compressed air is applied and the poppet 46 unseals the valve 22, the engine is turned over enough times to fully eliminate any trapped water and to permit the introduction of fresh combustion chamber and piston seal lubrication. Thereafter, the engine is in condition to be started. The engine may be turned over by various means including pneumatic or hydraulic. In a preferred embodiment, the means was a hydraulic motor. 
     The structure and method disclosed herein illustrate the principles of the present invention. The invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The embodiment of the invention described herein is to be considered in all respects as exemplary and illustrative rather than restrictive. Therefore, the appended claims rather than the foregoing description define the scope of the invention. All modifications to the embodiment described herein that come within the meaning and range of equivalence of the claims are embraced within the scope of the invention.