Consider the following statements.
1. Both Otto and Diesel cycles are special cases of dual combustion cycle.
2. Combustion process in IC engines is neither fully constant volume nor fully constant pressure process.
3. Combustion process in ideal cycle is replaced by heat addition from internal source in closed cycle.
4. Exhaust process is replaced by heat rejection in ideal cycle.
Which of the above statements are correct?
a) 1, 2 and 3 only (b) 3 and 4 only
(c) 1, 2 and 4 only (d) 1, 2, 3 and 4