Investigation of EF7 Engine Oil Priming Behavior using Gyrator Oil Pump

Delay of oil pressure increasing at the engine starting can effect on wear rate in the internal combustion engine. This paper investigates oil priming behavior of spark ignition engine using two types of gyrator oil pump. So, oil pressure in main gallery and cylinder head is measured with high response oil pressure sensor that synchronized with engine speed in different status of engine starting. Results shows the maximum delay of oil priming is about 2.5 second that is occurred in oil/oil filter changing. Using oil pump No. 2 after 12 hours, can decrease delay of oil priming from 1.93 second to 1.24 second in EF7 engine. Due to using hydraulic tappet technology in this engine, delay of oil priming effect on the engine wear rate and also hydraulic tappet life time. Results show that engine oil pump No. 2 can decrease crank shaft rotation in oil/oil filter changing, cold starting and warm staring status from 58, 45 and 18 revolution to 32, 19 and 11 revolution.