At numerous locations in the engine, oil is required in order to reduce friction and wear and also to decrease the noise level. In addition, modern internal combustion engines frequently have a large number of hydraulic components. It is thus important to ensure stable supply of oil to all these areas. This is particularly problematic when starting the engine, since at this point the majority of the oil is in the oil sump and must first be pumped through the whole oil circuit before it reaches the consumption devices. Through appropriately placed check valves, the oil holes and ducts in this circuit are prevented from emptying while the engine is stopped and rapid supply of oil can ensured when the engine is started. If individual components in the oil circuit induce pressure peaks into the oil supply, check valves can be used to prevent these pressure waves from spreading.
Check valves are available in different versions:
Valves with high opening pressures are used in order to allow flow only when a defined minimum oil pressure is reached. This function is used, for example, in the INA oil injection nozzles (a special type of check valves).
Through the use of high quality materials, the valves can withstand not only high peak temperatures but also dynamic loads without any problems. They are also characterised by a compact design and minimal pressure loss.