This document provides an introduction to a course on power engineering and machinery essentials. The course will cover internal combustion engines, turbo-machinery, thermal engineering, and refrigeration and low temperature engineering over 32 hours. It will include an introduction to the working principles and main components of internal combustion engines. The document outlines the learning objectives and main contents of the section on internal combustion engines, including the definition, early development, working principles, classifications, and components. It also describes how the power from combustion is transferred via the cylinder, piston, connecting rod and crankshaft to rotate the drive shaft and wheel.