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Questions (36 - 43)
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In this lesson, question (36-43) have been explained.

Harshit Aggarwal
Cleared UPSC ESE twice with Rank 63 and 90 in mechanical engg. Got 99 percentile in GATE. Cracked ONGC, BHEL,ISRO, SAIL, GAIL successfully

U
Unacademy user
sir notes kaha milege steel structure ke
Question number 37..how u calculated heat supply for figure B...plz explain bit more
i dint got quest no 37 at all.how u found the heat input
37 que how did you solve it .....im not getting the ans
  1. COURSE: Question on I C Engine Lesson: Question (36-43)


  2. About me Graduated from NIT Nagpur in 2008 Cleared Engineering Services Examination (ESE-UPSC) Exam Got the offer letter from most of the Maharatna and Navratna Companies Cleared GATE Exam Rate, Review, Recommend, Share Follow me on Unacademy at: https://unacademy.in/user/harshit aggarwal


  3. Question 36 Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because, in Otto cycle (a) Combustion is at constant volume (b) Expansion and compression are isentropic (c) Maximum temperature is higher (d) Heat rejection is lower Ans: d


  4. Question 37 Which one of the following hypothetical heat engine cycle represents maximum efficiency? 700 700 700 --300 300- 300 5V 5V


  5. Solution 37 Work done by all cases issame 5-1x (700-300) 800 units Heat input for (a)and(c)is same 700x (5-1) 280units Heat input for (b) is: 300x|--| +3x1- 300 (5-1)+ 1 (5-1)( 700-3001000 units Heat input for(d) is! 300x (5-1)- x(5-1): (700-300)| ..max imum n when min imum heat input is case(b) 2000units


  6. Question 38 For a spark ignition engine, the equivalence ratio ) of mixture entering the combustion chamber has values (a) < 1 for idling and > 1 for peak power conditions (b) > 1 for both idling and peak power conditions (c) > 1 for idling and < 1 for peak power conditions (d) < 1 for both idling and peak power conditions Ans b


  7. Question 39 Knocking tendency in a S.1. engine reduces with increasing (a) Compression ratio (c) Supercharging (b) wall temperature (d) engine speed Ans : d


  8. Question 40 For a conventional S.I. engine, what is the value of fuel-air ratio in the normal operating range'? (a) 0.056 0.083 (c) 0.0056 0.83 (b) 0.083 0.56 (d) 0.056 0.83 Ans a (A/F) for maximum power = 12 and (A/F) for Stoichiometric = 14.5 16 (A/F) for maximum fuel economy


  9. Question 41 The stoichiometric air/fuel ratio for petrol is 15: 1. What is the air/fuel ratio required for maximum power? (a) 16 1 18 (b) 15:1 (c) 12 1-18 (d) 9: 1 - 11 1 Ans : d


  10. Question 42 The air fuel ratio for idling speed of an automobile patrol engine is closer to (a) 10: 1 (b)15:1 (c) 17 1 (c) 21: 1 Ans a


  11. THANK YOU