Question 1 of 5
Compression ratio for diesel engine may have a range of:
A
8 to 10
B
16 to 20
C
10 to 14
D
20 to 25
Why: Diesel engines operate on compression ignition principle requiring high compression ratios to achieve auto-ignition temperatures. Typical range is 14:1 to 25:1, commonly 16-20 for standard engines. SI engines have lower ratios (8-12) to avoid knocking. Option B matches this standard range.
Question 2 of 5
A compression ignition engine is a:
A
Steam engine
B
Internal combustion engine
C
External combustion engine
D
Gas turbine
Why: Compression Ignition (CI) engine, or diesel engine, is an Internal Combustion Engine where fuel ignites due to high temperature from air compression. Unlike SI engines using spark, CI relies on compression ratios >14:1. Steam and external combustion engines use separate combustion chambers.
Question 3 of 5
Explain the working of a 2 stroke petrol engine.
Why: The answer provides complete cycle description with strokes, port timing, scavenging, and includes recreated diagram as required for engine working questions. Word count ~250, suitable for 5-6 marks.
Question 4 of 5
A test on a Single cylinder 4 Stroke Otto cycle engine yields the following data: 950 Nm torque, 7.6 bar Mean effective pressure, 280 mm Bore, 306 mm Stroke, 300 rpm, 0.003 kg/s fuel consumption with heating value of 42000 kJ/kg. Determine (i) Indicated Power (ii) Brake Power (iii) Mechanical Efficiency (iv) Indicated thermal efficiency (v) Brake thermal efficiency.
Why: Calculations use standard engine performance formulas. IP from IMEP, BP from torque, efficiencies as ratios. All steps shown with substitutions for full marks.
Question 5 of 5
Define the different types of mechanical properties of materials and explain their significance in engineering applications.
Why: This question asks for a comprehensive explanation of different types of mechanical properties and their significance. The answer should cover all major mechanical properties with definitions, examples, and practical applications in engineering.
