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Questions (44 - 51)
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In this lesson, questions (44 - 51) 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
Thanxxx sir....☺☺☺
SOlution of 44 is not fully understood what is 21 there?
only question no. 44 not understand.
Harshit Aggarwal
9 months ago
What is the doubt
Niraj Kumar
9 months ago
solution of 44 question. volume of oxygen requird ??? i meant solution of 44 question is my only doubt ???
  1. COURSE: Question on I C Engine Lesson: Question (44-51)


  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 44 If methane undergoes combustion with the stoichiometric quantity of air, the air-fuel ratio on molar basis would be: (a) 15.22: 1 (b) 12.30: 1 (c) 14.56: 1 (d) 9.52: 1


  4. Solution 44 CH4+202 CO2 +2H2O i.e. Volumes of O, are required for 1 volume of methane .. air fuel ratio =-x 100 = 9.52% 21


  5. Question 45 By higher octane number of SI fuel, it is meant that the fuel has (a) Higher heating value (c) Lower volatility (b) higher flash point (d) longer ignition delay Ans d


  6. Question 46 Which of the following factors increase detonation in the SI engine? 1. Increased spark advance 2. Increased speed. 3. Increased air-fuel ratio beyond stoichiometric strength 4. Increased compression ratio. Select the correct answer using the codes given below: (a) 1 and 3 (b) 2 and4 (c) 1, 2 and 4 (d) 1 and 4 Ans d


  7. Question 47 Consider the following statements: 1. In the SI engines detonation occurs near the end of combustion whereas in CI engines knocking occurs near the beginning of combustion 2. In SI engines no problems are encountered on account of pre-ignition 3. Low inlet pressure and temperature reduce knocking tendency in SI engines but increase the knocking tendency in CI engines. Which of the statements given above are correct? (a) 1, 2 and 3 (b) Only 1 and 2 (c) Only 2 and 3 d) Only 1 and3 Ans d


  8. Question 48 Consider the following statements: In order to prevent detonation in a spark-ignition engine, the charge away from the spark plug should have 1. Low temperature Which of the statements given above is/are correct? (a) Only 1 2. Low density 3. Long ignition delay (b) Only 2 (c) Only 3 (d) 1, 2 and 3 Ans : d


  9. Question 49 For minimizing knocking tendency is SI engine, where should the space plug be located? (a) Near inlet valve (b) Away from both the valves (c) Near exhaust valve (d) Midway between inlet and exhaust valves Ans b


  10. Question 50 In spark ignition engines knocking can be reduced by: (a) Increasing the compression ratio (b) Increasing the cooling water temperature (c) Retarding the spark advance (d) Increasing the inlet air temperature Ans: C


  11. THANK YOU