Role Of Thermostat In An Automotive Engine

By Author: Control Products
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In an automotive, the role of a thermostat is to regulate the operating temperature. It prevents coolant from circulating between the engine and radiator until it reaches a pre-determined temperature. This allows the thermostat to regulate the engine temperature and keep it within the desired operating range.

Thermostat switches can be used in a range of applications such as automotives, battery packs, electronics, heating pads, heaters, lighting, motors, transformers and more. All of these applications depend on a reliable thermostat switch to function properly.

A typical thermostatic line will include a bimetal snap action electromechanical disc and moisture resistant, hermetically sealed thermal cut-offs and protectors. They may also include electronic controls for additional temperature control.

Examining a thermostat will help understand its operations. Let us take a closer look at an automotive thermostat to understand how it really works. The role of a thermostat in an automotive is to accelerate the warm-up process of an engine and to regulate the operating temperature of the engine. Using ...
... a good quality thermostat reduces engine wear and emissions, provides adequate heater output, improves cold weather drivability, detours overheating and ensures fuel economy.

A thermostat will accomplish its job by blocking coolant from circulating between the engine and radiator until the engine reaches a certain temperature. The thermostat then opens to allow coolant regulate engine temperature and bring it within the desired operating range.

A thermostat has a rated temperature that when reached will open. It is usually placed within a metal or plastic housing where the radiator hose connects to the engine. Most vehicles have a thermostat based on reverse poppet design that opens against the flow of the coolant. It has a wax filled copper housing that pushes it open against the spring’s pressure. When the temperature of engines goes up beyond a point, the heat causes the wax in the thermostat to melt and expand, pushing against the piston inside a rubber boot, forcing the piston outward and opening the thermostat. It begins to unseat within 3 to 4 degrees of the rated temperature, allowing the coolant to circulate. A thermostat will maintain its open position until the cooling requirements of the engine are met.

A thermostat can also perform an additional function, shutting off a bypass circuit within the automotive engine when the radiator circuit is open. This ensures that hot spots do not form when the radiator circuit is closed.

The component will also have a system to remove air from the cooling system. It will usually have a jiggle pin that will allow air to pass through it. If it is not there, the thermostat will have some other method to remove the air.

A thermostat can move into two positions – open or closed. It may fail to open if the return spring malfunctions or debris prevents its movement. On the other hand, it may fail to move to the closed position due to corrosion, a defective electric cooling fan or overheating.

The only option in case of a malfunctioning thermostat is to replace it. Temperature rating of the replacement must be correct because using a wrong thermostat may cause extreme damage to engine performance, drivability and emissions. Dependable thermostat switches will provide long last performance working in engines.

The author of the article is associated with Control Products Inc. that deals in equipment like over temperature switches, linear position sensors, momentary switches and other such products.