Engine lubrication systems — meaning of forced-fed lubrication In a forced-fed lubrication system, oil is delivered to engine bearings and galleries primarily by:

Introduction / Context:
Lubrication architecture varies among engines. Forced-fed (also called pressure-fed) systems use a pump to distribute oil under pressure to critical bearings. Understanding the distinction from splash systems is vital for diagnosing low-pressure warnings and bearing failures.

Given Data / Assumptions:

• Modern passenger vehicle engine with full-flow filtration and oil pump.
• Pressurized galleries feed main, rod, and cam bearings.
• Some incidental splash still occurs but is not the primary delivery method.

Concept / Approach:
A positive-displacement oil pump draws oil from the sump and forces it through a filter into galleries at a regulated pressure. Jets and orifices meter flow to various components. Gravity and splash assist in returns and incidental lubrication but do not define the system type.

Step-by-Step Solution:
Identify key mechanism: pump-driven pressure supply.Trace path: sump -> pump -> filter -> main gallery -> components.Confirm that term forced-fed refers to this pressure distribution.

Verification / Alternative check:
Oil pressure sensors are installed in the main gallery, proving that pressure feed is central to the system operation.

Why Other Options Are Wrong:
Gravity feed is too weak for bearing hydrodynamic films. Splash-only systems are used in some small engines but are not forced-fed designs. "None of these" is incorrect because pump pressure is correct.

Common Pitfalls:
Assuming thicker oil raises pressure safely; in reality, the relief valve limits pressure and too-viscous oil can starve components at cold start.

Final Answer:
pressure created by the engine oil pump