Originally Posted By: stephen9666
I found an SAE paper talking about the oil pump design, which is described as sharing the oil pumping duty between two smaller pumps. I'm not willing to buy the paper, but here's the link and the abstract:
http://papers.sae.org/2006-01-0405/
Quote:
The Balance Shaft/Oil Pump Module for the new Hyundai Sonata NF Inline 4-cylinder engine family combines excellent NVH (noise, vibration and harshness, or “pleasibility”) and power consumption performance with minimized contribution to oil aeration. A two-stage drive ratio step-up and a balance shaft operating shape control strategy help minimize drive system noise emissions. Oil system noise emissions are minimized by dividing work between two gerotor pumps, and by the avoidance of cavitation at high speeds. Oil system performance benefits include high displacement at low speeds without attendant high power consumption or risk of cavitation at high speeds. A jet pump is used to efficiently recycle unused engine oil at high speeds, to both preserve energy and to resist cavitation, by boosting inlet pressure to the low speed flow-supplementing gerotor.
So, is this oil pump design somehow related to the knocking some owners experience? I have no idea and I've never read anything reliable that makes a connection.
Wow, that's definitely a different oil pump design from the simple gerotor positive displacement oil pumps I'm use to seeing. It still sounds like it's a positive displacement type of design (ie, "gerotor" was used in the description), but it's got some kind of two-stage setup. Without knowing more details, it's hard to say what's going on with the oil pump and oil flow through the RPM range. Could be at idle the pump goes into bypass mode really easy or something like that which could make the system sensitive to oil filters.
Question for stephen9666 - was the engine knocking when the engine was at full operating temperature and running only at or near idle? Did the knocking go away, stay the same or get worse with increased engine RPM?
I found an SAE paper talking about the oil pump design, which is described as sharing the oil pumping duty between two smaller pumps. I'm not willing to buy the paper, but here's the link and the abstract:
http://papers.sae.org/2006-01-0405/
Quote:
The Balance Shaft/Oil Pump Module for the new Hyundai Sonata NF Inline 4-cylinder engine family combines excellent NVH (noise, vibration and harshness, or “pleasibility”) and power consumption performance with minimized contribution to oil aeration. A two-stage drive ratio step-up and a balance shaft operating shape control strategy help minimize drive system noise emissions. Oil system noise emissions are minimized by dividing work between two gerotor pumps, and by the avoidance of cavitation at high speeds. Oil system performance benefits include high displacement at low speeds without attendant high power consumption or risk of cavitation at high speeds. A jet pump is used to efficiently recycle unused engine oil at high speeds, to both preserve energy and to resist cavitation, by boosting inlet pressure to the low speed flow-supplementing gerotor.
So, is this oil pump design somehow related to the knocking some owners experience? I have no idea and I've never read anything reliable that makes a connection.
Wow, that's definitely a different oil pump design from the simple gerotor positive displacement oil pumps I'm use to seeing. It still sounds like it's a positive displacement type of design (ie, "gerotor" was used in the description), but it's got some kind of two-stage setup. Without knowing more details, it's hard to say what's going on with the oil pump and oil flow through the RPM range. Could be at idle the pump goes into bypass mode really easy or something like that which could make the system sensitive to oil filters.
Question for stephen9666 - was the engine knocking when the engine was at full operating temperature and running only at or near idle? Did the knocking go away, stay the same or get worse with increased engine RPM?
