Exam Question
(a) Describe in detail a four stroke cycle. Why it is called so? (5)
(b) Draw 4-Stroke engine cycle, with crank position of each stroke (6)
(c) What is scavenging? Show the Scavenging step in the cycle diagram, what is it's importance.
Class 4 (4th Engineer)
MEKM
📅 Jun 2023
Reference Answer
### (a) The Four-Stroke Cycle and Its Name
The four-stroke cycle is a fundamental internal combustion engine operating principle. It is named the "four-stroke" cycle because it requires four distinct strokes (up or down movements) of the piston to complete one full thermodynamic or working cycle. These four strokes correspond to two complete revolutions of the crankshaft (720°).
The cycle consists of the following four strokes:
1. **Induction (or Suction) Stroke (0° - 180° Crank Rotation):**
The four-stroke cycle is a fundamental internal combustion engine operating principle. It is named the "four-stroke" cycle because it requires four distinct strokes (up or down movements) of the piston to complete one full thermodynamic or working cycle. These four strokes correspond to two complete revolutions of the crankshaft (720°).
The cycle consists of the following four strokes:
1. **Induction (or Suction) Stroke (0° - 180° Crank Rotation):**
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