Patent ID: 8298025

Claim:
A cooling system for cooling a hybrid marine propulsion system having an internal combustion engine, an electric motor, and a drive unit that transfers power from the internal combustion engine and the electric motor for propelling a marine vessel, the cooling system comprising: a first pump that pumps raw cooling water through a first cooling circuit for cooling the internal combustion engine and the drive unit, the first cooling circuit extending from a first upstream inlet to a downstream outlet; wherein the first cooling circuit conveys the raw cooling water that is pumped by the first pump through the internal combustion engine so as to cool a component of the internal combustion engine and then through the drive unit so as to cool a component of the drive unit; a bypass cooling circuit connected to the first cooling circuit at a location along the first cooling circuit that is between the component of the internal combustion engine and the component of the drive unit; and a second pump that pumps raw cooling water through a second cooling circuit for cooling the electric motor, the second cooling circuit being separate from the first cooling circuit and extending from a second upstream inlet to the bypass cooling circuit; wherein the second cooling circuit conveys the raw cooling water that is pumped by the second pump through the electric motor so as to cool a component of the electric motor and then to the bypass cooling circuit; wherein cooling water that is pumped by the second pump is received by the first cooling circuit via the bypass cooling circuit and is conveyed by the first cooling circuit through the drive unit so as to cool the component of the drive unit.