Eastern Mediterranean University Department of Mechanical Engineering Laboratory Handout

COURSE: MENG422 AUTOMOTIVE ENGINEERING I

Semester: Fall 2012

Name of Experiment: Thermostat testing

Instructor: Assist. Prof. Dr. Hasan HacışevkiAssistant: Mr.Ehsan Kiani

Submitted by:

Student No:

Group No:

Date of experiment: ……………

Date of submission: ……………

------------------------------------------------------------------------------------------------------------EVALUATION

Activity During Experiment & Procedure 30 %

Data , Results & Graphs 35 %

Discussion, Conclusion & Answer to Questions 30 %

Neat and tidy report writing 5 %

Overall Mark

Name of evaluator: Mr. EHSAN KIANI

OBJECT: The students will design and perform the opening and closing of a thermostat experimentally.

APPARATUS: 1. Electrical heater2. Thermostat3. Thermometer4. One cup of water

THEORY: A thermostat is a device for regulating the temperature of a system so

that the system's temperature is maintained near a desired set-point temperature.

Any liquid-cooled car engine has a thermostat that sits between the engine and the radiator. The thermostat in most cars is about 2 inches (5 cm) in diameter. Its job is to block the flow of coolant to the radiator until the engine has warmed up. When the engine is cold, no coolant flows through the engine. Once the engine reaches its operating temperature the thermostat opens. By letting the engine warm up as quickly as possible, the thermostat reduces engine wear, deposits and emissions.

Figure 1: Opened and closed position of thermostat

The secret of the thermostat lies in the small cylinder located on the engine-side of the device. This cylinder is filled with a wax that begins to melt at perhaps 82 oC (different thermostats open at different temperatures, but 82 oC is a common temperature).

Once the temperature of the coolant raises to between 82 – 90 oC, the thermostat starts to open, allowing fluid to flow through the radiator. The thermostatr starts to close as the temperature drops to 60 – 62 oC in the radiator.

A rod connected to the valve is expanding with the melting of the wax. When the wax is freezing as the water cools down it pulls the valve to close the passage.

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PROCEDURE:

1. Put the thermostat in the cup of water2. Put the cup on heater surface and heat the water until it boils3. Read and record the temperatures at every suitable time interval and at

the same time observe the opening of the thermostat4. Take the thermostat out of the boiling water and let it cool down and

observe how it is closing.5. Plot the results and discuss in discussion and conclusion section.

DATA:

Reading No. Temp (ºC) Opening (ºC)

1

2

3

4

5

6

7

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CONCLUSIONS:

1) What are the factors affecting the accuracy of the experiment? 2) Make error analysis for this experiment.

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