Question

Assertion A: Super charged petrol engines employ lower compression ratios.
Reason R: Super charging results in increase in the intake temperature of engine, reduction of ignition delay and thus tendency to detonate or pre-ignite.
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both A and R are correct and R is the correct explanation of A
• B. Both A and R are correct but R is NOT the correct explanation of A
• C. A is correct but R is not correct
• D. A is not correct but R is correct

Hint:

Supercharging increases temperature and pressure.
Lower compression ratios are used to prevent detonation.
This is a common design consideration.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Supercharging increases the air intake pressure.
We need to analyze the effect on compression ratio and detonation.

Step 2: Key Formula or Approach:
No specific formula.
Need to understand the effects of supercharging.

Step 3: Detailed Explanation:
Supercharging increases the intake air temperature and pressure.
Higher intake temperature increases the tendency for detonation.
To avoid detonation, lower compression ratios are used in supercharged petrol engines.
Thus, A is correct.
The reason given (increase in intake temperature, reduction of ignition delay, tendency to detonate) is the reason for using lower compression ratios.
So, R is correct and explains A.

Step 4: Final Answer:
Both A and R are correct, and R is the correct explanation of A.
Hence, the correct option is (A).