1. Field of the Invention
The present invention is generally related to an engine coolant draining system of a marine engine and, more particularly, to the use of a unidirectional air valve as a passive air vent to allow air to flow into a coolant conduit when a liquid coolant is being drained from the cooling system of the engine.
2. Description of the Prior Art
Many different systems are known to those skilled in the art for draining or flushing marine engine cooling systems. In addition, various types of unidirectional valves are known to those skilled: in the art.
U.S. Pat. No. 6,135,064, which issued to Logan et al on Oct. 24, 2000, discloses an engine drain system. An engine cooling system is provided with a manifold that is located below the lowest point of the cooling system of the engine. The manifold is connected to the cooling system of the engine, a water pump, a circulation pump, the exhaust manifolds of the engine, and a drain conduit through all of the water can be drained from the engine.
U.S. Pat. No. 6,343,965, which issued to Biggs et al on Feb. 5, 2002, discloses a pneumatically actuated marine engine water drain system. A drain system for a marine vessel is provided which includes one or more pressure actuated valves associated with the coolant water drain system. The boat operator is provided with a pressure controller that allows pressure to be introduced into the system for the purpose of actuating the drain valves and, as a result, opening various drain conduits to allow cooling water to drain from the engine cooling system into the bilge or overboard.
U.S. Pat. No. 6,050,867, which issued to Shields et al on Apr. 18, 2000, discloses a drain system for a marine vessel. The drain system is provided for a marine vessel in which three types of drain operations can be performed at one common location near the transom of the marine vessel. A multiple conduit structure is provided with a plurality of fluid passages extending at least partially through its structure. A first fluid passage allows the bilge of the boat to be drained. A second fluid passage allows multiple locations on the engine to be drained through a common port. A second sealing plug is provided to close the second passageway that prevents fluid communication between the various fluid conduits used to drain the cooling water of the engine. A third fluid passage is provided through the multiple conduit structure to allow lubricating oil to be drained from the engine. A single hole through the transom of a boat is all that is required to allow the multiple conduit structure to be attached to the boat and extend through the transom for the purpose of draining the bilge, the engine cooling water, and the engine lubricating fluid.
U.S. Pat. No. 5,944,211, which issued to Woodnorth et al on Aug. 31, 1999, describes a container system including an air evacuation valve. The container system includes a one-piece, one-way valve. The container system can be evacuated by pressing the lid, thereby forcing air out of the one-way valve. The one-way valve does not allow air to enter the container system. The one-way valve includes an interface or release which allows air to enter the container system when the interface is pressed. The one-way valve is preferably an umbrella-shaped valve made of silicone or plastic.
U.S. Pat. No. 5,893,609, which issued to Schmidt on Apr. 13, 1999, describes an air pumping system for an automotive seat. An inflatable lumbar support system for a vehicle seat includes an inflatable air cell, or cells, coupled by an air line to a motorized diaphragm pump. The outlet valve of the pump is in the form of an umbrella valve which serves not only to seal the pump on the intake strokes, but is of such character to provide the sole seal between the air cell and pump, thereby eliminating the need to have a separate external check valve between the pump and air cell to assure that the air cell does not leak once pressurized.
U.S. Pat. No. 5,826,554, which issued to Kuhnel et al on Oct. 27, 1998, describes pressure relief means for a thin wall air intake pipe for an internal combustion engine. The valve is installed in an opening provided in a thin wall of an air intake pipe, which supplies combustion air from a flow control device to a cylinder of an internal combustion engine, to relieve excess pressure in the pipe. The valve includes a socket connected to a segment of the air intake pipe, and an elastomer, umbrella valve member is supported in the socket to normally cover the opening in the pipe and to undergo deformation when the pressure in the pipe reaches a predetermined value to uncover the opening and to connect the interior of the pipe to the ambient atmosphere.
U.S. Pat. No. 5,816,430, which issued to Gruber on Oct. 6, 1998, describes a fuel tank vent valve for heaters. A jerrycan holds liquid fuel. A cap for the jerrycan includes an air vent valve assembly having an umbrella-shaped check valve. The check valve is sensitive to a pressure differential between an interior of the jerrycan and the atmosphere. As fuel is dispensed from the jerrycan, a volume of an air chamber within the jerrycan increases, thereby decreasing the pressure in the jerrycan and creating a vacuum. The vacuum causes the rate at which fuel is dispensed from the jerrycan to decrease. The check valve dislodges when the pressure within the jerrycan becomes less than the pressure of the atmosphere and additional air is introduced into the jerrycan. The air fills the expanded volume of the air chamber, thereby increasing the pressure, eliminating the vacuum and causing the rate at which fuel is dispensed to increase.
U.S. Pat. No. 5,173,033, which issued to Adahan on Dec. 22, 1992, describes a one-way umbrella valve and portable fluid pumping device including same. The portable fluid pumping device includes a valve assembly having a pair of one-way umbrella valves controlling the flow of air to produce a positive pressure at one port and a negative pressure at another port. Each umbrella valve includes a valve stem having a neck received within the mounting opening, and an umbrella skirt integrally joined to the neck to overlie the valve opening. The umbrella skirt is relatively thin for its complete extent, and the juncture between the umbrella skirt and neck of the valve stem is of frusto-conical configuration increasing in diameter from the neck to the umbrella skirt.
U.S. Pat. No. 4,513,784, which issued to Farrand et al on Apr. 30, 1985, describes a check valve assembly. The assembly is disclosed having a valve chamber with an inlet port and an outlet port. An elastomeric umbrella valve is contained in the chamber between the ports and is attached by an integral stem in a preloaded condition to normally close the inlet port and be deflectable in response to differential fluid pressure acting in one direction to open same to permit forward fluid flow there through past the valve and through the chamber to the outlet port. An inwardly projecting retention arrangement formed in the chamber retains the valve in operational relationship with the inlet port in the event the valve becomes unattached so that any backward flow from the outlet port still forces closure of the valve on same. A bypass channel arrangement also formed in the chamber maintains forward fluid flow past the valve to the outlet port in the event the valve becomes unattached.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
It would be significantly beneficial if a draining system for a marine engine could be provided with a device that inhibits the creation of a vacuum within the cooling system when coolant is drained from the system.
An engine coolant draining system, made in accordance with the preferred embodiment of the present invention, comprises an internal combustion engine and a coolant conduit disposed at least partially in thermal communication with heat producing portions of the internal combustion engine. In most cases, the coolant conduit comprises hoses attached to the internal combustion engine and also cavities formed in various parts of the engine and its exhaust system. A coolant, such as water, is circulated through the coolant conduit in order to remove heat from the engine and its associated components. It should be understood that some marine engines are configured to be directly cooled by lake or sea water circulated through the hoses and engine cavities to directly remove heat from heat producing regions of the engine. Alternative configurations provide a closed cooling system in which a first liquid, such as ethylene glycol, is circulated in direct thermal communication with the heat producing portions of the engine and a second liquid, such as water, is circulated in thermal communication with the first liquid in a heat exchanger. The second liquid, which is typically sea or lake water, is drawn from the body of water in which the marine vessel is operated and circulated through the heat exchanger to remove heat from the closed cooling liquid, such as ethylene glycol. The water is then returned to the sea or lake from which it was drawn.
A unidirectional air valve, in a preferred embodiment of the present invention, is disposed in fluid communication with the coolant conduit to inhibit flow from flowing out of the coolant conduit through the unidirectional air valve while allowing fluid to flow into the coolant conduit through the unidirectional air valve. The unidirectional air valve either inhibits or allows fluid flow through its construction as a result of the differential pressure across the valve.
The present invention can further comprise a housing structure, such as a thermostat housing connected in fluid communication with the coolant conduit. The unidirectional air valve is attached to the housing structure in order to dispose the unidirectional air valve in fluid communication with the coolant conduit. The coolant conduit is configured to conduct water in thermal communication with the heat producing portions of the internal combustion engine. The system can further comprise a water pump connected in fluid communication with the coolant conduit for causing liquid coolant to flow through the coolant conduit. The unidirectional air valve, in a particularly preferred embodiment of the present invention, is an umbrella-shaped valve.
In certain embodiments, a vent module is provided and shaped to be inserted into the coolant conduit, preferably in association with the housing structure. The housing structure can be a thermostat housing structure associated with the internal combustion engine. The vent module is shaped to support the unidirectional air valve in fluid communication with the coolant conduit. A screen member can be disposed within the vent module in order to inhibit debris from flowing into contact with an operative portion of the unidirectional air valve. The unidirectional air valve or umbrella-shaped valve, is responsive to the pressure differential between the pressure within the coolant conduit and the pressure external to the coolant conduit. The unidirectional air valve inhibits fluid from flowing out of the coolant conduit through the unidirectional air valve when the pressure within the coolant conduit is higher than the pressure external to the coolant conduit and allows fluid to flow into the coolant conduit through the unidirectional air valve when the pressure external to the coolant conduit is higher than the pressure within the coolant conduit.
The present invention facilitates the draining of water from the cooling system of the internal combustion engine by allowing air to flow into an upper region of the coolant conduit in order to prevent the formation of a vacuum that would otherwise adversely affect the proper draining of water from the cooling system of the engine.