To find the efficiency of any engine, it is necessary to divide useful work into spent and to increase by 100 percent. For the heat engine find this size on the relation of the power increased by work duration to heat generated at fuel combustion. Theoretically the efficiency of the heat engine is determined by a ratio of temperatures of the fridge and heater. For electric motors find the relation of its power to power of the consumed current.
It is required to you
- passport of the internal combustion engine (ICE), thermometer, tester
Instruction
1. Determination of efficiency of DVS Find its power in technical documentation of this concrete engine. Fill in a number of fuel in its tank and start the engine that he worked some time on whole revolutions, developing the maximum power specified in the passport. By means of a stop watch note operating time of the engine, having expressed it in seconds. After a while stop the engine, and merge fuel reserves. Having taken away final volume from the initial volume of the filled-in fuel, find the volume of the spent fuel. Using the table, find its density and increase by volume, having received the mass of the spent m=ρfuel \• V. Express weight in kilograms. Depending on a type of fuel (gasoline or diesel fuel), determine its specific heat of combustion by the table. For determination of efficiency increase the maximum power by operating time of the engine and for 100%, and result consistently divide into its mass and specific heat of combustion of efficiency = % P· t·100 / (q•m).
2. For the ideal thermal car, it is possible to apply Carnot's formula. For this purpose learn temperature of combustion of fuel and take the fridge temperature (exhaust gases) the special thermometer. Translate temperature taken in degrees Celsius in an absolute scale for what to value add number 273. For determination of efficiency from number 1 take away the relation of temperatures of the fridge and heater (fuel combustion temperature) of efficiency = (1-Tkhol/Tnag)•100%. This option of calculation of efficiency does not consider mechanical friction and heat exchange with the external environment.
3. Determination of efficiency of the electric motor Recognize the rated power of the electric motor, by technical documentation. Connect it to a current source, having achieved the maximum turns of a shaft, and by means of a tester measure value of tension on it and current in a chain. For determination of efficiency the power stated in documentation, divide into the work of current on tension, result increase by the efficiency of 100% = P•100% / (I•U).