Systems and methods for a cooling fluid circuit

#Embodiments of the subject matter disclosed herein relate to cooling circuits of engine systems.

#Engines may utilize recirculation of exhaust gas from an engine exhaust system to an engine intake system, a process referred to as exhaust gas recirculation (EGR), to reduce regulated emissions. An EGR system may include an EGR cooler to cool the exhaust gas before it enters the intake system. In some examples, the EGR cooler and the engine may be coupled in parallel in a cooling fluid circuit. In such an example, however, an amount of cooling fluid may be increased and/or a flow rate of the cooling fluid may be doubled, for example, as similar flow rates of cooling fluid are sent through the engine and the EGR cooler. In other examples, the EGR cooler may be positioned downstream of the engine in the cooling circuit. As such, an engine operating temperature may be reduced due to cooler cooling fluid flowing through the engine, thereby reducing a thermal efficiency of the engine. Further, the cooling circuit may be pressurized in order to maintain the cooling fluid under its boiling point. In this case, degradation of a pressure cap may lead to engine or EGR cooler failure.

#Thus, in one embodiment, an example system includes an exhaust gas recirculation cooler. The system further includes a cooling fluid circuit in which the exhaust gas recirculation cooler and an engine are positionable in series with the exhaust gas recirculation cooler disposed upstream of the engine.

#The present invention will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below:

#FIG. 1 shows a schematic diagram of an engine with an exhaust gas recirculation system in a marine vessel.

#FIG. 2 shows a schematic diagram of a cooling fluid circuit which includes an engine and an exhaust gas recirculation cooler.

#The following description relates to various embodiments of methods and systems for cooling an engine system. In one exemplary embodiment, a system comprises an exhaust gas recirculation (EGR) cooler and an engine. The system further comprises a cooling fluid circuit in which the EGR cooler and the engine are positioned in series and the EGR is disposed upstream of the engine. In such an embodiment, the cooling fluid cools exhaust gas via the EGR cooler before cooling the engine. In this manner, a temperature of the engine may be maintained at a higher temperature, resulting in improved thermal efficiency. In some embodiments, the system may further include a pump disposed upstream of the EGR cooler in the cooling fluid circuit. In such a configuration, the pump supplies high pressure cooling fluid to the EGR cooler such that the cooling fluid is maintained below its boiling point. Thus, the need for a pressure cap may be reduced and degradation of components of the system due to degradation of the pressure cap may be reduced.

#In one embodiment, the cooling fluid circuit may be part of an engine system positioned in a vehicle. In some embodiments, a marine vessel may be used to exemplify one of the types of vehicles having engine systems to which the cooling fluid circuit may provide cooling. Other types of vehicles may include locomotives, on-highway vehicles, and off-highway vehicles other than locomotives or other rail vehicles, such as mining equipment. Other embodiments of the invention may be used for engine systems that are coupled to stationary engines. The engine may be a diesel engine, or may combust another fuel or combination of fuels. Such alternative fuels may include gasoline, kerosene, biodiesel, natural gas, and ethanol. Suitable engines may use compression ignition and/or spark ignition.

#FIG. 1 shows a block diagram of an exemplary embodiment of a system, herein depicted as a marine vessel 100, such as a ship, configured to operate in a body of water 101. The marine vessel 100 includes an engine system 102, such as a propulsion system, with an engine 104. However, in other examples, engine 104 may be a stationary engine, such as in a power-plant application, or an engine in a rail vehicle propulsion system. In the exemplary embodiment of FIG. 1, a propeller 106 is mechanically coupled to the engine 104 such that it is turned by the engine 104. In other examples, the engine system 102 may include a generator that is driven by the engine, which in turn drives a motor that turns the propeller, for example.