Question

The injector nozzle of a compression ignition engine is required to inject fuel at sufficiently high pressure in order to __________

(a) inject fuel in a chamber of high pressure at the end of the compression stroke

(b) inject fuel at a high velocity to facilitate atomization

(c) ensure that penetration is not high

(d) all of the mentioned

I have been asked this question in exam.

This interesting question is from Comparison of Two Stroke S.I. and C.I. Engines topic in division Two Stroke Engines of IC Engine

Answer 1

The correct answer is:

**(d) all of the mentioned**

In a compression ignition (CI) engine, the injector nozzle must inject fuel at a high pressure to accomplish several critical tasks:

1. **Inject fuel into a high-pressure chamber** at the end of the compression stroke, which requires overcoming the cylinder's pressure.

2. **Inject fuel at a high velocity** to facilitate atomization, ensuring that the fuel forms fine droplets for efficient combustion.

3. **Control fuel penetration** to avoid excessive penetration, which could lead to inefficient mixing with air and incomplete combustion.

Thus, all the options (a), (b), and (c) are correct, making (d) the best answer.