Allied & ICAR Exam Bank • ALLIED_2989 MCQ • 1 Mark

Section 3: Farm Power

Farm Power

Subtopic: Thermodynamic principles of I.C. engines

Question Statement:

Why can commercial tractor diesel engines operate at much higher compression ratios ($16:1\text{ to }22:1$) than gasoline spark-ignition engines ($8:1\text{ to }11:1$)?

Options:

  • (A) Only air is compressed in diesel engines, eliminating the danger of premature detonation (engine knock)
  • (B) Diesel fuel is lighter than petrol
  • (C) Diesel engines have no pistons
  • (D) Diesel operates at lower temperatures

Answer Key:

A

Step-by-Step Solution & Explanation

Because diesel compresses only air during compression, fuel self-ignition limit does not restrict compression ratio.
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