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What is the purpose of an engine crankcase?
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gasoline engine
Cross section of a V-type engine.
The engine crankcase serves several essential functions in the operation of a gasoline engine:
- Structural Housing: The crankcase is the portion of the engine block located below the cylinder bores. It provides the necessary enclosure for the crankshaft, which is the primary rotating component of the engine.12
- Lubrication Reservoir: The lower section of the crankcase, often formed by an oil pan, serves as a sump or reservoir for lubricating oil. This oil is essential for reducing friction between moving parts and assisting in engine cooling.13
- Emission Management: The crankcase acts as a collection point for leaked combustion gases. Modern engines utilize a positive crankcase ventilation (PCV) valve to capture these gases and return them to the intake manifold to be reburned in the combustion chamber, thereby limiting the discharge of unburned hydrocarbons into the atmosphere.2