Anti-ingestion system for a marine drive

1. An anti-ingestion system for a marine drive having an internal combustion engine having an exhaust system discharging exhaust at an exhaust outlet below the surface of a body of water in which the marine drive is operating, and having a cooling system drawing cooling water from the body of water and pumping the cooling water through a water conduit to an exhaust mixing point to discharge into and mix with exhaust from said exhaust system, an anti-ingestion valve connected in communication with said water conduit, said anti-ingestion valve being operated by differential pressure thereacross to a closed condition when said engine is operating in an on state and said cooling water is being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said closed condition blocking passage of cooling water therepast, said anti-ingestion valve being operated by differential pressure thereacross to an open condition when said engine is in an off state and said cooling water is not being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said open condition permitting passage of air therethrough and communication of atmospheric pressure through said water conduit to said exhaust mixing point to relieve vacuum in said exhaust system wherein said anti-ingestion valve comprises a movable valve member moving in a first direction to said closed condition, and moving in a second opposite direction to said open condition, wherein said valve member moves in each of said first and second directions in response to differential pressure and without a biasing spring.

2. The anti-ingestion system according to claim 1 wherein said anti-ingestion valve is actuated to said open condition after turn-off of said engine, and remains in said open condition until next turn-on of said engine.

3. The anti-ingestion system according to claim 1 wherein said anti-ingestion valve comprises a diaphragm check valve.

4. An anti-ingestion system for a marine drive having an internal combustion engine having an exhaust system discharging exhaust at an exhaust outlet below the surface of a body of water in which the marine drive is operating, and having a cooling system drawing cooling water from the body of water and pumping the cooling water through a water conduit to an exhaust mixing point to discharge into and mix with exhaust from said exhaust system, an anti-ingestion valve connected in communication with said water conduit, said anti-ingestion valve being operated by differential pressure thereacross to a closed condition when said engine is operating in an on state and said cooling water is being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said closed condition blocking passage of cooling water therepast, said anti-ingestion valve being operated by differential pressure thereacross to an open condition when said engine is in an off state and said cooling water is not being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said open condition permitting passage of air therethrough and communication of atmospheric pressure through said water conduit to said exhaust mixing point to relieve vacuum in said exhaust system wherein said anti-ingestion valve is located along said water conduit in sufficiently close proximity to said exhaust mixing point to quickly communicate vacuum in said exhaust system to said anti-ingestion valve.

5. The anti-ingestion system according to claim 4 wherein said water conduit is connected at a connection point to an exhaust elbow water jacket to flow to said exhaust mixing point, and wherein said anti-ingestion valve is located within 100 ±50 mm of said connection point.

6. An anti-ingestion system for a marine drive having an internal combustion engine having an exhaust system discharging exhaust at an exhaust outlet below the surface of a body of water in which the marine drive is operating, and having a cooling system drawing cooling water from the body of water and pumping the cooling water through a water conduit to an exhaust mixing point to discharge into and mix with exhaust from said exhaust system, an anti-ingestion valve connected in communication with said water conduit, said anti-ingestion valve being operated by differential pressure thereacross to a closed condition when said engine is operating in an on state and said cooling water is being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said closed condition blocking passage of cooling water therepast, said anti-ingestion valve being operated by differential pressure thereacross to an open condition when said engine is in an off state and said cooling water is not being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said open condition permitting passage of air therethrough and communication of atmospheric pressure through said water conduit to said exhaust mixing point to relieve vacuum in said exhaust system wherein said anti-ingestion valve operates between said open and closed conditions in response to 75 ±25 mm water column differential pressure.

7. An anti-ingestion system for a marine drive having an internal combustion engine having an exhaust system discharging exhaust at an exhaust outlet below the surface of a body of water in which the marine drive is operating, and having a cooling system drawing cooling water from the body of water and pumping the cooling water through a water conduit to an exhaust mixing point to discharge into and mix with exhaust from said exhaust system, an anti-ingestion valve connected in communication with said water conduit, said anti-ingestion valve being operated by differential pressure thereacross to a closed condition when said engine is operating in an on state and said cooling water is being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said closed condition blocking passage of cooling water therepast, said anti-ingestion valve being operated by differential pressure thereacross to an open condition when said engine is in an off state and said cooling water is not being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said open condition permitting passage of air therethrough and communication of atmospheric pressure through said water conduit to said exhaust mixing point to relieve vacuum in said exhaust system wherein said anti-ingestion valve is located along said water conduit in sufficiently close proximity to said exhaust mixing point to minimize the amount of water which must be evacuated when said anti-ingestion valve changes from said closed condition to said open condition to in turn provide rapid communication of atmospheric air pressure through said anti-ingestion valve to said exhaust system at said exhaust mixing point.

8. An anti-ingestion system for a marine drive having an internal combustion engine having an exhaust system discharging exhaust at an exhaust outlet below the surface of a body of water in which the marine drive is operating, and having a cooling system drawing cooling water from the body of water and pumping the cooling water through a water conduit to an exhaust mixing point to discharge into and mix with exhaust from said exhaust system, an anti-ingestion valve connected in communication with said water conduit, said anti-ingestion valve being operated by differential pressure thereacross to a closed condition when said engine is operating in an on state and said cooling water is being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said closed condition blocking passage of cooling water therepast, said anti-ingestion valve being operated by differential pressure thereacross to an open condition when said engine is in an off state and said cooling water is not being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said open condition permitting passage of air therethrough and communication of atmospheric pressure through said water conduit to said exhaust mixing point to relieve vacuum in said exhaust system wherein:

said water conduit is connected at a connection point to an exhaust elbow water jacket to flow to said exhaust mixing point;

said anti-ingestion valve is in a side branch conduit extending from said water conduit;

said exhaust elbow water jacket has a lower segment passing said cooling water therethrough from said water conduit;

said side branch conduit at said anti-ingestion valve extends gravitationally above said lower segment of said exhaust elbow water jacket.

9. The anti-ingestion system according to claim 8 wherein said anti-ingestion valve is at a higher gravitational height than said lower segment of said exhaust elbow water jacket.

10. An anti-ingestion system for a marine drive having an internal combustion engine having an exhaust system discharging exhaust at an exhaust outlet below the surface of a body of water in which the marine drive is operating, and having a cooling system drawing cooling water from the body of water and pumping the cooling water through a water conduit to an exhaust mixing point to discharge into and mix with exhaust from said exhaust system, an anti-ingestion valve connected in communication with said water conduit, said anti-ingestion valve being operated by differential pressure thereacross to a closed condition when said engine is operating in an on state and said cooling water is being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said closed condition blocking passage of cooling water therepast, said anti-ingestion valve being operated by differential pressure thereacross to an open condition when said engine is in an off state and said cooling water is not being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said open condition permitting passage of air therethrough and communication of atmospheric pressure through said water conduit to said exhaust mixing point to relieve vacuum in said exhaust system wherein said anti-ingestion valve is connected to said water conduit at a Tee fitting.

11. The anti-ingestion system according to claim 10 comprising a J-conduit having a lower hook leg connected to said water conduit at said Tee fitting, and having an upper leg extending upwardly from said lower hook leg, wherein said anti-ingestion valve is located at said upper leg.

12. The anti-ingestion system according to claim 11 wherein said anti-ingestion valve comprises a movable valve member moving up and down at said upper leg.

13. An anti-ingestion system for a marine drive having an internal combustion engine having an exhaust system discharging exhaust at an exhaust outlet below the surface of a body of water in which the marine drive is operating, and having a cooling system drawing cooling water from the body of water and pumping the cooling water through a water conduit to an exhaust mixing point to discharge into and mix with exhaust from said exhaust system, an anti-ingestion valve connected in communication with said water conduit, said anti-ingestion valve being operated by differential pressure thereacross to a closed condition when said engine is operating in an on state and said cooling water is being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said closed condition blocking passage of cooling water therepast, said anti-ingestion valve being operated by differential pressure thereacross to an open condition when said engine is in an off state and said cooling water is not being pumped through said water conduit to said exhaust mixing point, said anti-ingestion valve in said open condition permitting passage of air therethrough and communication of atmospheric pressure through said water conduit to said exhaust mixing point to relieve vacuum in said exhaust system wherein:

said cooling system comprises a drain valve having an open state draining said cooling system of said cooling water including when said exhaust outlet is below the surface of said body of water;

said anti-ingestion valve is in said open condition when said drain valve is in said open state, whereby to relieve possible vacuum in said cooling system and facilitate said draining of said cooling water therefrom.