Piston for internal combustion engine i.e. spark-ignited flat engine, has ventilation groove formed at groove flanks within annular grooves and extending from bar into region of groove base, and oil return hole provided within grooves

摘要

The piston (1) has a piston ring bar provided with multiple annular grooves that are formed for receiving an oil scraper ring. The grooves are provided with an upper groove flank, a lower groove flank and a groove base. A ventilation groove (10) is formed at the upper and lower groove flanks within the annular grooves and extends from the piston ring bar into a region of the groove base. An oil return hole is provided within the annular grooves and positioned by the ventilation groove, where depth of the ventilation groove is 0.3 mm. An independent claim is also included for an internal-combustion engine comprising a combustion chamber and an intake valve.