A cooling apparatus of an engine of the invention has a circulation passage for supplying cooling water to head and block passages through a heat exchanger. The apparatus circulates the cooling water through the circulation passage when a second condition is satisfied and then, a first condition is satisfied. The first condition includes a water supply condition that a supply of the cooling water to the exchanger is requested. The second condition includes the water supply condition and a condition that a cooling water temperature is lower than an engine completely-warmed water temperature.

A fuel-based thermal management system may comprise a heat exchanger configured to thermally couple a fluid and a fuel. A controller may be configured to modulate a flow of the fluid to the heat exchanger. A tangible, non-transitory memory may be configured to communicate with the controller. The controller may determine a temperature of the fluid, estimate a dissolved oxygen concentration in the fuel using a first fuel temperature, a flight cycle time, and at least one of an altitude measurement or a ambient pressure measurement, and modulate the flow of the fluid to the heat exchanger based on the dissolved oxygen concentration.

A fuel-based thermal management system may comprise a heat exchanger configured to thermally couple a fluid and a fuel. A controller may be configured to modulate a flow of the fluid to the heat exchanger. A tangible, non-transitory memory may be configured to communicate with the controller. The controller may determine a temperature of the fluid, estimate a dissolved oxygen concentration in the fuel using a first fuel temperature, a flight cycle time, and at least one of an altitude measurement or a ambient pressure measurement, and modulate the flow of the fluid to the heat exchanger based on the dissolved oxygen concentration.

An internally cooled internal combustion piston engine and method of operating a piston engine is provided, with the combination of liquid water injection, higher compression ratios than conventional engines, and leaner air fuel mixtures than conventional engines. The effective compression ratio of the engines herein is greater than 13:1. The engines may employ gasoline or natural gas and use spark ignition, or the engines may employ a diesel-type fuel and use compression ignition. The liquid water injection provides internal cooling, reducing or eliminating the heat rejection to the radiator, reduces engine knock, and reduces NOx emissions. The method of engine operation using internal cooling with liquid water injection, high compression ratio and lean air fuel mixture allow for more complete and efficient combustion and therefore better thermal efficiency as compared to conventional engines.

An internally cooled internal combustion piston engine and method of operating a piston engine is provided, with the combination of liquid water injection, higher compression ratios than conventional engines, and leaner air fuel mixtures than conventional engines. The effective compression ratio of the engines herein is greater than 13:1. The engines may employ gasoline or natural gas and use spark ignition, or the engines may employ a diesel-type fuel and use compression ignition. The liquid water injection provides internal cooling, reducing or eliminating the heat rejection to the radiator, reduces engine knock, and reduces NOx emissions. The method of engine operation using internal cooling with liquid water injection, high compression ratio and lean air fuel mixture allow for more complete and efficient combustion and therefore better thermal efficiency as compared to conventional engines.

An exhaust manifold is for an outboard motor having an internal combustion engine. The exhaust manifold has an exhaust conduit that conveys exhaust gas from the internal combustion, and a cooling jacket on the exhaust conduit. The cooling jacket defines a first cooling water passage that conveys cooling water in a first direction alongside the exhaust conduit, a second cooling water passage that conveys the cooling water from the first cooling water passage in an opposite, second direction alongside the exhaust conduit, and third cooling water passage that is separate from the first and second cooling water passages and conveys spent cooling water from the internal combustion engine to a thermostat.

An internally cooled internal combustion piston engine and method of operating a piston engine is provided, with the combination of liquid water injection, higher compression ratios than conventional engines, and leaner air fuel mixtures than conventional engines. The effective compression ratio of the engines herein is greater than 13:1. The engines may employ gasoline or natural gas and use spark ignition, or the engines may employ a diesel-type fuel and use compression ignition. The liquid water injection provides internal cooling, reducing or eliminating the heat rejection to the radiator, reduces engine knock, and reduces NOx emissions. The method of engine operation using internal cooling with liquid water injection, high compression ratio and lean air fuel mixture allow for more complete and efficient combustion and therefore better thermal efficiency as compared to conventional engines.

An internally cooled internal combustion piston engine and method of operating a piston engine is provided, with the combination of liquid water injection, higher compression ratios than conventional engines, and leaner air fuel mixtures than conventional engines. The effective compression ratio of the engines herein is greater than 13:1. The engines may employ gasoline or natural gas and use spark ignition, or the engines may employ a diesel-type fuel and use compression ignition. The liquid water injection provides internal cooling, reducing or eliminating the heat rejection to the radiator, reduces engine knock, and reduces NOx emissions. The method of engine operation using internal cooling with liquid water injection, high compression ratio and lean air fuel mixture allow for more complete and efficient combustion and therefore better thermal efficiency as compared to conventional engines.

A cooling system includes a charge air cooler system that includes a first stage that receives charge air via a charge air flow path and receives coolant fluid via a first coolant fluid flow path. A second stage receives charge air from the first stage via the charge air flow path, outputs the charge air, and receives the coolant fluid via a second coolant fluid flow path. A third stage receives and outputs the charge air from the second stage via the charge air flow path and receives the coolant fluid via a third coolant fluid flow path. The cooling system includes a low temperature radiator system that includes a low temperature radiator that directs the coolant fluid toward the third stage via the third coolant fluid flow path and includes a high temperature radiator system that directs the coolant fluid toward the first stage and second stage.

A dual seated by-pass valve is provided for a surface heat exchanger. The valve provides a power element and at least two seats and two poppets which are spring biased and responsive to movement of the power element to open and close pathways to core cooling channels and de-congealing channels.