What is the purpose of a separate electric lube oil pump in a combustion engine?

The purpose of a separate electric lube oil pump in a combustion engine is to provide initial lubrication on start-up. When an engine is started, the components are often not yet lubricated because the main oil pump may take some time to build pressure. This initial lubrication is crucial to reduce wear and tear on engine parts, preventing damage during the critical moments right after the engine is turned on.

The electric lube oil pump ensures that oil reaches critical areas before the engine runs, providing a protective film on bearings and other moving components. This helps in avoiding metal-to-metal contact that can occur without proper lubrication, especially when the engine is cold and oil viscosity is higher.

While increased fuel efficiency, circulating cooling water, and measuring oil temperature are important functions in an engine's operation, they do not capture the vital role of the electric lube oil pump in protecting the engine during the start-up phase. The focus on initial lubrication underscores the importance of safeguarding internal engine components right from the moment the engine begins to operate.