The present invention relates generally to automotive cooling systems, and more particularly to an apparatus that incorporates the functions of a radiator and a thermostat into a single housing.
Current automotive cooling systems are composed of distinct elements including a radiator, which acts as a heat exchanger, and a separate engine mounted thermostat. The thermostat allows coolant to flow through the radiator when the coolant is above a predetermined temperature. Three most commonly used radiator styles are a downflow design, a crossflow design, and a U-flow design.
In the radiator downflow design, the radiator has an upper tank and a lower tank, with the two tanks being connected by a member having an array of finned tubes. Hot coolant flows through a side tube into the upper tank, through the normal array of finned tubes from the upper tank to the lower tank where the water is cooled, and exits the radiator at the lower tank through a second side tube.
In the crossflow design, the radiator includes left and right side tanks, which are connected by a set of finned tubes. Coolant typically flows in the top of the right side tank, flows across the set of finned tubes, and exits the radiator through a lower portion of the left side tank.
The U-flow radiator design is similar to the crossflow design. The U-flow design includes left and right side tanks, which are connected by an upper and a lower set of finned tubes. Coolant typically flows in the top of the right side tank, across the upper set of finned tubes to the left side tank, and returns to the right side tank through the lower set of finned tubes.
In the downflow and crossflow designs, coolant enters one side of the radiator and exits a different side of the radiator as opposed to the U-flow design, which allows the coolant to enter and exit the same side of the radiator.
All three of these designs have a separately located thermostat, apart from the radiator. The thermostat is fluidically coupled to the radiator by additional connections. In order for the thermostat to be removed or replaced, tools are required and the coolant needs to be drained from the cooling system. When the thermostat is reinstalled or replaced, contact surfaces between the thermostat and the engine need to be cleaned, which may include scraping off any remaining gasket material. Also in replacing the thermostat, new gasket material is required to properly seal the contact services. Therefore, removal and replacement of the thermostat is time consuming and therefore costly.
In U.S. Pat. Nos. 4,432,410 and 5,305,826 a temperature sensitive valve is used within the left side tank of a U-flow design radiator. The ""410 patent describes a temperature sensitive valve that acts as a traditional thermostat in that it permits coolant to flow through the left side tank when the coolant temperature is below a predetermined temperature. When the coolant is above a predetermined temperature, the temperature sensitive valve changes the coolant flow direction, such that the coolant flows in an upper portion of the left side tank, across the finned tubes, and than exits a lower portion of the left side tank. The temperature sensitive valve in the ""826 patent is regulated such that the valve adjusts the amount of coolant that is permitted to flow across the finned tubes and how much remains flowing only through the left side tank. Both the ""410 and ""826 temperature sensitive valves are difficult to remove and replace, and therefore costly to repair. In order to repair either valve, the coolant needs to be drained from the cooling system, causing additional time and expense. Also when initially filling the cooling system, if the system temperature is not above a predetermined value and the valves are not completely open in either the ""410 patent or the ""826 patent, there is a potential for air gaps to ensue because of the valves restricting coolant flow. Air gaps can cause hot spots in the cooling system, which in turn may cause degradation of engine and cooling system components. In order to assure that the valves are completely open to prevent air gaps, time is needed to heat the coolant.
It would therefore be desirable to develop an automotive cooling system that is quick and easy to fill without a potential for air gaps, has a minimal amount of components, has a thermostat that is easy to replace, and is of low cost to produce.
The forgoing and other advantages are provided by an apparatus that incorporates the functions of a radiator and a thermostat into a single housing. A thermostat cartridge assembly for a cooling system of an automotive vehicle is provided including a housing. The housing includes a first opening, a second opening, and a direct-flow opening. A thermostat mechanism located at least partially within the housing adjusts the amount of the coolant flowing between the first opening, the second opening, and the direct-flow opening. An attachment mechanism attaches the thermostat cartridge assembly to the cooling system. A releasing mechanism attaches and disengages the thermostat cartridge assembly to and from the radiator.
One advantage of the present invention is that the thermostat may be removed or replaced without draining coolant in the cooling system, thereby saving costs involved in disposal and purchasing of coolant.
Another advantage of the present invention is that the thermostat is easily removable and replaceable without tools or gasket scraping.
Yet another advantage of the present invention is that during initial filling of the cooling system, since the thermostat is easily removable, the cooling system may be easily and completely filled, in a minimum amount of time without leaving air gaps in the cooling system.
The above mentioned advantages alone save costs in manufacturing, producing, and usage of the automotive vehicle cooling system.