Examkin

Question

Difficulty: MediumEngine Principles and Internal Components

In an internal combustion engine, cylinder firing produces intermittent torque pulses. What is the primary mechanical purpose of the heavy flywheel mounted to the rear of the crankshaft?

  1. A
    Actuating the intake and exhaust valves at precisely timed intervals
  2. Storing rotational momentum to smooth out power pulses between cylinder firing intervalsAnswer
  3. C
    Metering the ratio of air and fuel drawn into the intake manifold
  4. D
    Converting reciprocating piston travel into lateral drivetrain motion

Answer

Storing rotational momentum to smooth out power pulses between cylinder firing intervals
Because internal combustion engines deliver power in discrete combustion pulses, the heavy mass of the flywheel provides rotational inertia. This inertia stores kinetic energy during each power stroke and releases it to keep the crankshaft spinning smoothly through the non-power phases.

Step-by-Step Solution

1
Analyze the mechanical challenge in multi-cylinder or single-cylinder reciprocating engines
Combustion occurs in brief bursts during individual cylinder power phases, resulting in uneven torque delivery across the engine cycle.
An engine requires a mechanism to maintain continuous rotation during non-power phases such as intake, compression, and exhaust.
2
Identify the internal component dedicated to rotational inertia and momentum storage
The flywheel is a heavy disc bolted directly to the crankshaft flange that absorbs kinetic energy during combustion and releases it between firing events.
Rotational inertia dampens torsional vibrations and prevents engine stalling or rough operation between individual firing events.

Key Concept

Flywheel Function and Rotational Momentum in Internal Combustion Engines
Estimated Time:1m 0s
Rate this question

Topics

Engine Principles and Internal Components

More questions from this topic