Marine engine cooling systems and methods

Abstract

The present invention, in one aspect, is a cooling system for a marine engine and includes cylinder cooling jackets, cylinder head cooling jackets, and thermostatic and pressure controls which facilitate safely operating the engine with low water flow rates. In one specific embodiment, the cooling system is employed in a marine engine including a V-type cylinder block with two cylinder banks and a valley between the banks. Each cylinder bank includes a plurality of cylinder bores (e.g., each cylinder bank includes three cylinder bores in a six cylinder engine), and respective exhaust ducts extend from and are in flow communication with each cylinder bore. Respective coolant flow paths extend from the valley to a section of each cylinder bore water jacket adjacent each cylinder exhaust duct. Specifically, water is provided from the valley to adjacent each exhaust duct in the cylinder banks. Each cylinder bore water jacket includes an outlet at an upper portion of each said cylinder bank. A water flow path extends from each cylinder bore water jacket outlet to a respective cylinder head water jacket. Variable thermostats are in flow communication with each cylinder bore water jacket, and each thermostat is in flow communication with a dump. Each flow path through the respective thermostats is in parallel with a respective cylinder head. The thermostats allow cooling of the cylinders to be thermostatically controlled. Specifically, the amount of water supplied to the cylinder head cooling jackets depends on the temperature condition at the thermostats. The cylinder head water jackets are in flow communication with a parallel connected blow off valve and thermostat. The blow off valve and thermostat are in flow communication with the water dump. When the blow off valve opens, maximum cooling is provided in that water flows unrestricted from the valley, to the cylinder cooling jackets, to the cylinder head cooling jackets, through the blow off valve to the dump.