Section A
Q1. Define indicated thermal efficiency and relative efficiency of an IC engine. Why is relative efficiency preferred as a measure of engine performance? Define depreciation and list the different methods employed in calculating depreciation. Also, indicate which method is common for farm machines. A disk harrow with a draft of 18 N is required to be pulled at a speed of 4 km/h in a firm untilled field by a tractor having maximum PTO power rating of 40 kW. Calculate the actual PTO power needed to pull the harrow, if the tractive and transmission coefficient for a 2-wheel drive tractor for the untilled firm soil is 0.75. Enlist the reasons for lubricating the different moving parts of IC engine. Also, state what you understand by 'Multigrade' lubricating oil. What is Solar Constant? Write about the instruments that are used to measure solar energy. Define the following:
(e) Cetane number
(i) Cetane number
(ii) Volumetric efficiency of IC engine
(iii) Firing order in multicylinder engine
(iv) Compression ratio