Oil pump system for an engine

An oil pump system for an engine, comprising:

• a fixed displacement oil pump;
• an oil pump housing defining a pocket configured to receive the fixed displacement oil pump therein, a cavity in fluid communication with the pocket, and an oil pump outlet passage connecting the pocket to a first end of the cavity;
• a low pressure relief passage defined by the pump housing for selectively fluidly coupling the cavity to a pressure relief area defined by the pump housing and adapted to be in fluid communication with an oil sump of the engine;
• a high pressure relief passage defined by the pump housing for selectively fluidly coupling the cavity to the pressure relief area, the high pressure relief passage being separate from the low pressure relief passage;
• an annular pressure relief valve positioned in the cavity and comprising a body having a first end, a second opposite end, a first internal bore extending from the valve first end, a second internal bore extending from the valve second end, and at least one slot extending through the body and in communication with the first internal bore, the first internal bore facing the first end of the cavity and being separated from the second internal bore by an internal wall member, the at least one slot including an arcuate shaped sidewall extending in an axial direction toward the internal wall member;
• and
• a biasing member positioned in the second internal bore and biasing the pressure relief valve to a first position where the pressure relief valve engages the first end of the cavity;
• wherein the pressure relief valve is configured to overcome a biasing force of the biasing member and translate to a second position aligning the at least one slot with the low pressure relief passage to selectively provide low pressure relief to the oil pump in response to pressurized oil from the pump outlet passage that flows into the first internal bore and into engagement with the internal wall member being greater than a first predetermined pressure value, and to further translate to a third position aligning the at least one slot with the high pressure relief passage to selectively provide high pressure relief to the oil pump in response to pressurized oil from the pump outlet passage being greater than a second predetermined pressure value, the second predetermined pressure value being greater than the first predetermined pressure value.