Internal Combustion Engine:
The device which converts the chemical energy of the fuel into thermal energy and use this thermal energy to produce mechanical work is called IC Engine. They consist of a cylinder, piston, crank, crankshaft, inlet and exhaust valve, connecting rod, etc.
Why testing of an IC Engine is necessary?
With the help of testing, we can find out the information about the engine which cannot be determined by calculations. By performing these tests we can satisfy the consumer as the rated power output with the guaranteed fuel consumption. Actually, the maximum tests which are performed on IC engines are for commercial purposes to find the following:
- The overload carrying capacity of the engine
- The quantity of cooling water required on brake power basis in kg per kW-hr
- Brake Power (which is also known as rated power) with guaranteed fuel consumption.
- The amount of lubricating oil required.
- The amount of cooling water required.
Generally, testing of an IC engine is carried out only for the commercial purpose but we compare these actual results with theoretical or ideal results that we obtain by the thermodynamic testing.
Tests Performed on Internal Combustion Engine:
- Willian’s line method
- Morse-Key test
- Motoring Test
Willian’s Line Method:
Willian’s line method or Fuel rate extrapolation method is used to find the amount of fuel consumption when engine does not develop any power. It is the graph between the brake power (B.P) on x-axis and fuel consumption rate (Plotted on y-axis) and its intercept on the negative x-axis. This graph will provide the frictional power of the engine. This is generally used for Compression ignition engines.
Morse-key Test:
It is only applicable for multi cylinder engines and for both spark ignition engine and compression ignition engine. But the compression Ignition engine is more preferrable.
Here, in this test we bring each cylinder under free state one by one. This can be done by the following two ways:
- Shorting of Spark Plug
- Cutting off fuel supply
The main purpose of the morse-key test is to find out the friction power of the engine and mechanical efficiency of engine.
Motoring Test:
In motoring test, if we use petrol engine then shorting of spark plug is done and for diesel engine we cut-off the fuel supply. We provide the power by external motor in order to drive engine at rated speed is the frictional power of the engine.
