General Motors has just patented a passive two-stage oil separation assembly for crankcase ventilation, GM Authority has uncovered.
Assigned serial number 10,151,225 at the United States Patent and Trademark Office (USPTO), the GM patent was filed on October 26th, 2016 and granted on December 11th, 2018. Titled “integrated oil separator assembly for crankcase ventilation”, the patent lists Ko-Jen Wu and Jason C. Melecosky as its inventors.
The patent is comprised of two primary parts – an explanation of the claims made in regard to the oil separator assembly’s abilities, and a collection of six images that illustrate the actual parts as well as their locations on a hypothetical engine.
The proposed two-stage oil separation system is comprised of the first oil separator, which is mounted to the wall of the crankcase, and a second oil separator mounted to the first oil separator. This second separator provides further filtration.
The location of the first oil separator is dependent on the location of the first blow-by flow passage of the crankcase ventilation system as well as the first drain passage. The first oil separator’s internal baffling acts as a second blow-by flow and third drain passage, with the third drain passage flowing to the second drain passage of the crankcase ventilation system. A second oil separator is then mounted to the first oil separator, aligning with the third drain passage. The design of the second oil passage can then be altered to include a plurality of internal baffles or a filter.
In Plain English
If all that engineering jargon is too much, here’s an explanation in simpler terms: the crankcase ventilation system will vent air out through a first oil separator, and – through the use of check-valves – it may continue to a second oil separator. The direction of the air is dictated by blow-by flow passages, and the separated oil is returned through drain passages.
The air vented from the crankcase can go to one or more openings, including an air intake system which can include a turbocharger. The second oil separator can include a pressure regulator valve that can regulate the system’s pressure via check-valves.
An improved oil separation process can alleviate pre-ignition due to oil in the combustion chamber, which is a common symptom of small-displacement, turbo-charged engines.
In addition, the presence of oil in the combustion chamber can lead to particulates in the exhaust as a byproduct, which raises health concerns.
Where To From Here?
As emissions regulations continue to become ever more stringent, General Motors will be forced to deliver innovative ways to deliver cleaner and more efficient engines for its vehicles. In that regard, this two-stage oil separation system can certainly assist in doing so. The idea makes even more sense when one considers the fact that GM is beginning to use a highly-boosted, four-cylinder engine in full-size pickup truck applications – as it’s doing with the 2.7L I4 L3B engine in the 2019 Chevrolet Silverado 1500 and 2019 GMC Sierra 1500.
Considering the patent was originally filed over two years ago (in October of 2016), we believe that GM is looking to implement the proposed oil separation technology on a production engine at some point in the near future. In short, we expect to see a system like this one implemented in the near future as GM continues to improve and refine its technology while also meeting the demands of emissions regulations.
We have confirmed with Tom Read of GM Powertrain that the 3.6L LGX, 3.6L LGZ and 2.0L Turbo LSY engines are equipped with an integrated two-stage oil passive oil separation system. As such, it would seem that these engines are using the technology described in the patent.
To note, most GM engines use a passive system, but only the HFV6 and 2.0-liter LSY engines feature a two-stage system.
Check out the complete patent application in its nine-page glory right here (PDF file format).