Patent Application
20120234266
The present invention is in the field of locomotive diesel engines and cooling systems. More particularly, the present invention is in the technical field of cooling systems for diesel engines utilizing multiple flow paths to provide flexibility, efficiency and reduced emissions.
Cooling systems for internal combustion engines, such as those powering locomotives, are known in the art for the purpose of maintaining engine temperature and lubricating oil temperatures within desired operating parameters. In addition, the cooling system is used to reduce the temperature of the charge air. In typical cooling systems, ambient air is forced through heat exchangers and the cooling capability is constrained by the temperature of the ambient air as well as other factors. There are two common types of cooling systems commonly found in locomotives.
For example, the first type of cooling system consists of a Y-shaped pipe on the engine which splits the coolant flow into two radiators. The coolant exits both the radiators and enters an oil cooler, which is in parallel to an expansion tank. From the oil cooler the coolant is combined with the outlet of the expansion tank and then it enters a pair of pumps that are mounted on the engine block. The pumps then circulate the coolant through fluid passages within the engine. Some of the fluid flows through passages in the cylinder liners and heads while the remainder exits the engine at the opposite end of the pumps and enters a pair of intercoolers that are located on each side of the engine. After the coolant absorbs the heat from the intercooler, it then re-enters the engine via another fluid passage and combines with the fluid coming from the cylinder liners and heads. The coolant then exits the engine and is diverted through the Y-shaped pipe to the radiators restarting the cooling process.
The above prior art cooling system allows the engine cylinder liners, cylinder heads, oil cooler and the intercoolers and crankcase exhaust elbows that are located in the upper deck of the crankcase to be maintained at acceptable temperature levels. The coolant temperature is at its lowest as it is coming out of the radiators, and this coolant is provided to the oil cooler. As the coolant continues through the system and flows through the engine and intercoolers, it may warm up considerably and not lose heat until it once again passes through the radiators. In this typical prior art cooling system, the engine coolant enters the engine around 180 degrees Fahrenheit and exits the engine around 190 degrees Fahrenheit.
The second type of prior art cooling system is similar to the first type with the exception that the coolant flows out of the engine through a water discharge header and is combined with coolant that exits from the intercooler and turbocharger. The coolant then enters a control valve that will either direct the coolant to the radiator or expansion tank depending upon the temperature of the coolant. If the coolant is warm, it will be directed to the radiators and then to the expansion tank. The coolant then passes through the oil cooler to a pump which circulates the coolant through the water inlet header into the engine turbocharger and intercoolers. If the coolant temperature is cold, which is typical during engine start up, the control valve shall route the coolant such that it bypasses the radiators, and flows directly into the expansion tank, and continues the process as described above. This type of cooling system is designed to maintain a coolant temperature between 182 degrees Fahrenheit and 200 degrees Fahrenheit.
These traditional cooling systems of the prior art have a disadvantage because these systems do not allow the flexibility to provide a lower coolant temperature to the intercoolers. The lowest coolant temperature that is received by the intercoolers of both systems is dictated by the coolant temperature that is required by the cylinder liners and cylinder head.
The disclosed split cooling system and method is directed to overcoming one or more of the disadvantages listed above.
In one aspect, the present invention disclosed herein is directed to a cooling system for an internal combustion engine, comprising an engine; at least one intercooler for receiving combustion air from a turbocharger, the intercooler comprising an air-to-liquid heat exchanger for exchanging heat between the combustion air and a liquid coolant; an intercooler radiator; at least one engine coolant radiator; an expansion tank; an oil cooler; and at least one pump, wherein the dedicated fan is controlled by a temperature switch or microprocessor controller and wherein the at least one engine coolant radiator and the intercooler radiator are located on opposite sides of the engine.
The present application is directed toward the technical field of cooling systems for diesel engines utilizing multiple flow paths to provide flexibility efficiency, and reduced emissions.
Referring to
Engine 102 includes internally formed cooling passages and/or a water jacket through which the some of the liquid coolant flows and absorbs energy from engine 102, thereby cooling engine 102. At least one pump 112 is used to circulate the liquid coolant throughout cooling system 100, as described below.
The remainder of the liquid coolant exits engine 102 and is directed to at least one intercooler 104, said intercooler used to improve the volumetric efficiency of engine 102 by increasing the intake air charge density. For example, as air is compressed in the turbocharger (not shown), the temperature of the air increases, which consequently decreases the air density of the charge air delivered to the cylinders in engine 102. This hotter, less dense air decreases combustion efficiency. In order to increase combustion efficiency, at least one intercooler 104 lowers the temperature of the charge air to increase the air's density, which in turn increases combustion efficiency. Intercooler 104 may be a charge air cooler which utilizes an air-to-liquid heat exchange device. As the liquid coolant flows through intercooler 104, heat may be transferred from intercooler 104 to the liquid coolant. After the liquid coolant exits intercooler 104, it is directed back into engine 102, where it enters another fluid passage and combines with the coolant that has passed through the water jacket.
After the liquid coolant exits engine 102, it may be diverted by a Y-pipe device 114 into at least one parallel flow path. In the prior art cooling system 100 shown in
Radiator 106 may be a heat exchange device of any type used in the art of engine cooling systems. As the liquid coolant flows through at least one radiator 106, at least one fan 116 will provide an increased air flow through radiator 106 and the liquid coolant will lose some its accumulated heat and return to a lower temperature. As the cooler liquid coolant exits at least one radiator 106, at least a portion of the liquid coolant is directed to oil cooler 110. Oil cooler 110 is another heat exchange device used to maintain the lubricating oil for engine 102 at an optimal temperature. The remainder of the liquid coolant not directed to oil cooler 110 may be directed to expansion tank 108.
As the liquid coolant exits oil cooler 110, it may be combined with the outlet of expansion tank 108, and the combined liquid coolant flow path may then enter at least one pump 112. At least one pump 112 may be mounted on engine 102. At least one pump 112 may then circulate the liquid coolant through engine 102, restarting the cooling cycle described above.
Referring now to
One feature of the present invention is that the additional split cooling loop provided by intercooler radiator 220 provides a lower temperature liquid coolant to the at least one intercooler 104. As explained above in reference to
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The embodiments described above are given as illustrative examples only. It will be readily appreciated by those skilled in the art that many deviations may be made from the specific embodiments disclosed in this specification without departing from the invention. Accordingly, the scope of the invention is to be determined by the claims below rather than being limited to the specifically described embodiments above.
