MARINE ENGINE COOLING SYSTEM EMPLOYING A THERMOSTATIC VALVE MEANS AND A PRESSURE RELIEF VALVE MEANS

摘要

A pressure relief valve for the engine of an outboard motor includes a valve plate connected to a stem and spring loaded water cooling passageway in close spaced relation to a thermostatically controlled valved passageway. The stem extends outwardly through a water discharge chamber directly in communication with the discharge passageway to the lower unit of the motor. A diaphragm is connected to the outer end of the valve stem and is sealed to form a wall of the water discharge chamber. The discharge chamber is normally under a slight water discharge pressure whenever the thermostatic valve is open and thus creates a very slight pressure on the diaphragm which is balanced by the closure spring until such time as the pump pressure within the cooling system is sufficient to overcome the force of the spring. As the relief valve opens, the internal passageway pressure is transmitted to the discharge chamber. This results in the diaphragm rapidly moving outwardly and establishing the full open position of the relief valve. This, in turn, results in a reduction in the internal passageway pressure.