mean effective pressure This topic contains 1 reply, has 2 voices, and was last updated by Surjeet Sankararaj 5 years ago. Author Posts October 9, 2013 at 5:43 pm #3096 ashu123Participant Points: 18 How to calculate Indicated mean effective pressure of 4 stroke SI engine by indicator diagram? kindly explain with images of indicator diagram… which is generally used in IC lab October 9, 2013 at 7:43 pm #3098 Surjeet SankararajKeymaster Points: 631 Refer this article: http://mechteacher.com/otto-cycle-mean-effective-pressure-derivation/ I have explained the derivation of mean effective pressure of Otto cycle (used in 4 stroke SI engine). The indicator diagram (PV diagram) can be found in the article itself. From the PV diagram (indicator diagram), find p1, p4, V1 and V2. Then find the following: k=p4/p1 r=V1/V2 Apply the values of k, r and p1 in the mean effective pressure formula found in the last line of the article. You will get the indicated mean effective pressure. (Take γ=1.4) Author Posts You must be logged in to reply to this topic.