Answer:
Out of the four given options
Option ii. Constant volume heat addition
is the correct option.
Explanation:
The combustion phase of Otto cycle with air standard assumptions can be replaced by heat addition at constant volume i.e., in isochoric process where volume is constant.
In Otto cycle combustion occurs at constant volume or we can say that Otto cycle undergoes isochoric combustion unlike diesel cycle where combustion takes place at constant presurre or we can say that diesel cycle undergoes isobaric process of combustion.
Therefore, in Otto cycle, combustion phase can be replaced by isochoric heat addition.
