Exam Question
Describe following terms with respect to Diesel Engine with suitable diagram;
(a) Natural Aspiration. (4)
(b) Scavenging (4)
(c) Supercharging (4)
(d) Types of Super charging in two stroke engine. (4)
Class 4 (4th Engineer)
MEKM
📅 Sep 2023
Reference Answer
**(a) Natural Aspiration (4 marks)**
* **Concept**: Natural aspiration refers to the process where an internal combustion engine draws air into its cylinders solely due to the pressure differential created by the downward movement of the piston during the intake stroke (or by the scavenging pump action in certain two-stroke designs, though the term primarily applies to four-stroke engines without forced induction). The air enters at atmospheric pressure.
* **Mechanism of Operation**:
* During the intake stroke of a four-stroke engine, the piston moves downwards, increasing the volume within the cylinder. Simultaneously, the intake valve opens.
* **Concept**: Natural aspiration refers to the process where an internal combustion engine draws air into its cylinders solely due to the pressure differential created by the downward movement of the piston during the intake stroke (or by the scavenging pump action in certain two-stroke designs, though the term primarily applies to four-stroke engines without forced induction). The air enters at atmospheric pressure.
* **Mechanism of Operation**:
* During the intake stroke of a four-stroke engine, the piston moves downwards, increasing the volume within the cylinder. Simultaneously, the intake valve opens.
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