What is the function of the bypass valve in engine oil pump (I.C.E?

By pass valve is provided on the oil pump of engine because of safety from higher pressure.A oil pump is set on a definite pressure,on that pressure pump continuously work, If any how pressure increases from the recommended pressure then by pass valve opens on that extra pressure and pressurise oil return to the reservoir,due to this our system is safe from higher pressure.

in case of high pressure the bypass valve allow flow of oil to ease the pressure

maintain the correct pressure to keep the system operating. In case of any faulty pressure It vents the pressure .