Class 4 (4th Engineer) MEKM 📅 Jan 2026

Exam Question

Explain the method of obtaining the following diagrams on a 2-Stroke Main propulsion Engine:

(a) Power Card, showing vital point of diagram. (4)

(b) Out of Phase diagram indicating vital points. (4)

(d) Compression diagram and its importance (4)

Reference Answer

### Introduction to Indicator Diagrams
Indicator diagrams are graphical representations of the pressure inside an engine cylinder versus the volume (or piston travel) throughout the thermodynamic cycle. They are obtained using a mechanical instrument called an engine indicator (e.g., Dobbie-McInnes type) fitted to an indicator cock on the cylinder head. These diagrams are indispensable diagnostic tools for assessing engine performance, calculating power, and troubleshooting faults related to combustion, gas exchange, and the mechanical condition of cylinder components.
### (a) Power Card (In-Phase Diagram)
**Method of Obtaining:**

Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.

View plans Browse library

← Browse more questions

Prepare on Android — MeoMock on Google Play