Question 238Motor Plants - Assistant Engineer

The correct answer is D) relief valve. The maximum lube system operating pressure for a diesel engine is normally regulated by a relief valve. The relief valve is designed to open and release excess pressure in the system, preventing the pressure from exceeding the recommended maximum. This protects the engine and lubricating components from damage due to excessive pressure. The other options are incorrect because: A) an orifice in the pump suction would not regulate the maximum pressure, B) a special filter design does not control the maximum pressure, and C) the pressure drop through the filter is not the primary means of regulating the maximum pressure.