Electronically controlled thermostat

#This invention relates generally to the field of internal combustion engines and more particularly to the cooling systems used to control the heat generated by such combustion engines. Most particularly, this invention relates to thermostats used to control the flow of the coolant between an engine and a heat exchanger such as a radiator.

#Thermostats have been known and used extensively to control the circulation of coolant in internal combustion engines. In the past, the thermostats have taken the form of valves which are immersed in the coolant in, for example, a coolant conduit. Most commonly the valves include a valve member which spans the conduit and sits against a valve seat. Thus, in the closed position the valve substantially blocks the flow of coolant, for example, to the radiator, allowing the coolant to re-circulate past the engine and to heat up more quickly.

#Typically such valves include a closed body containing a thermally expandible material such as wax. A piston is provided which is thrust outward upon the expansion of the wax due to higher coolant temperatures. The piston lifts the valve off the valve seat to allow the coolant to circulate past a heat exchanger, such as a radiator. This lowers the temperature of the coolant and removes heat from the engine. A spring is provided to urge the valve to a closed position so that in the resting or cooled state the valve is closed. Thus, when an engine is first started, the valve will be closed allowing the engine to attain its optimum running temperature more quickly.

#Reference will now be made to drawings which depict, by way of example only, preferred embodiments of the invention and in which:

#FIG. 1 is a front cross-sectional view of the present invention in place in a coolant conduit with the valve closed;

#FIG. 2 is a side cross-sectional view of the invention of FIG. 1;

#An apparatus for controlling a temperature of an engine by controlling a flow of liquid engine coolant as illustrated generally as 10 in FIG. 1. The apparatus includes an end cap 12, and a main body 14 which defines a fluid conduit 16. The main body 14 includes an attachment flange 18 having a pair of opposed fastener openings 20 for attaching the device 10 onto the cooling system of, for example, a vehicle. An O-ring 22 is provided to permit a liquid tight seal to be made between the part 10 and the remainder of the engine system. Although a particular configuration for end caps and main body is shown, it will be appreciated that various forms of fitting could be used without departing from the present invention.

#Associated with the end cap 12 is an instrumentation package including a pair of electrical leads 24 which are connected to a fitting 26 external to the conduit 16. A retaining ring 28 is associated with the instrumentation package 26 which includes an O-ring 30 to provide a liquid tight seal with respect to liquid in the conduit 16. The retaining ring 28 is preferably formed with a sloped surface 32 for interfacing with the O-ring 30.

#Electrical leads 24 are most preferably connected to an electrical circuit controlled, for example, by an Engine Control Module (ECM). Typically an ECM will include a plurality of sensors which are used to sense various engine and vehicle parameters so the performance of the engine can be optimized. The present invention comprehends either using existing sensors, if appropriate and available, or using added sensors to provide the ECM with sufficient information to take advantage of the present invention as described herein.