Prosecution Insights
Last updated: April 19, 2026
Application No. 19/019,809

TWO-STROKE ENGINE FOR A VEHICLE

Non-Final OA §103
Filed
Jan 14, 2025
Examiner
KIM, JAMES JAY
Art Unit
3747
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Brp-Rotax GmbH & Co. Kg
OA Round
1 (Non-Final)
70%
Grant Probability
Favorable
1-2
OA Rounds
2y 4m
To Grant
97%
With Interview

Examiner Intelligence

Grants 70% — above average
70%
Career Allow Rate
467 granted / 665 resolved
At TC average
Strong +27% interview lift
Without
With
+27.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 4m
Avg Prosecution
28 currently pending
Career history
693
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
54.8%
+14.8% vs TC avg
§102
22.9%
-17.1% vs TC avg
§112
20.1%
-19.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 665 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claim Rejections - 35 USC § 103 The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. Claims 1-4 and 6-10 are rejected under 35 U.S.C. 103 as being unpatentable over Hofbauer et al (US 2014/0298984 hereinafter “Hofbauer”) in view of Kobayashi et al (US 2020/0248651 hereinafter “Kobayashi”). In regards to claim 1: Hofbauer teaches a two-stroke engine assembly comprising an engine (Paragraph [0002] recites the engine being a two-stroke engine) comprising: at least one cylinder formed (20) by the engine block, a cylinder volume being defined by the at least one cylinder (20); at least one piston (10) disposed in the at least one cylinder (20); and a protrusion (formed with rings 110 and 112) extending into the cylinder volume, the protrusion defining a lubrication groove (shown below in annotated Figure 12) therein, the lubrication groove being disposed below the at least one piston and in the cylinder (20); and a lubrication system providing oil to the engine (Paragraph [0002] recites lubrication provided to the engine), the lubrication groove being shaped and arranged to collect oil droplets pushed by air toward the at least one piston during operation and to redirect the oil droplets to at least one pre-determined location in the at least one cylinder, wherein during operation oil and air will form on a piston surface (98) and the protrusion (rings 110 and 112) will scrape the oil off of the piston surface (98) and redirect them to the upper portion of the piston surface (98) below a piston ring (14) (Figures 1A-1C show the operation of the piston). Hofbauer does not specify an engine block and a crankshaft disposed in the engine block. Kobayashi teaches an engine block and a crankshaft (31) disposed in the engine block. It would have been obvious to one of ordinary skill in the art at the time of filing of the application to specify the engine of Hofbauer to have an engine block and crankshaft as taught by Kobayashi in order to provide a housing for the internal components of the engine and the crankshaft to attach to the piston so that cycling of the piston can be translated into mechanical power. PNG media_image1.png 658 587 media_image1.png Greyscale Annotated Figure 12 of Hofbauer In regards to claim 2: Hofbauer teaches the engine block comprises: a crankcase (Paragraph [0003] of Hofbauer recites a crankcase and Kobayashi teaches a crankcase (13)), and at least one cylinder block connected to the crankcase (Shown in Figure 1 of Kobayashi). In regards to claim 3: Hofbauer teaches the protrusion is integrally connected to and formed by the engine block, the protrusion being formed by a cylinder wall defining the at least one cylinder (Shown in Figure 1a of Hofbauer, formed defined as “bring together parts or combine to create (something).” using www.google.com search term: “formed definition”). In regards to claim 4: Hofbauer teaches at least one cylinder insert (102) disposed in the at least one cylinder; and wherein the at least one cylinder insert includes the protrusion (rings 110 and 112) and the lubrication groove defined in the protrusion (Shown above in annotated Figure 12 of Hofbauer and wherein Paragraph [0038] of Hofbauer recites the protrusion in the cylinder insert (cylinder liner)). In regards to claim 6: Hofbauer teaches the lubrication groove (rings 110 and 112) is continuous about a portion of the at least one cylinder (102); and the lubrication groove is open to the at least one cylinder at the at least one pre-determined location (Figure 12 of Hofbauer shows the groove being continuous). In regards to claim 7: Hofbauer teaches the at least one pre-determined location is an exhaust side of the at least one cylinder, wherein Hofbauer teaches grooves in two diagonally opposite quadrants when viewed from a top down vantage point as shown in Figure 12 of Hofbauer, wherein if a left half or right half is the exhaust side, a groove will exist on one of the left half or right half, or wherein if a top half or bottom half is the exhaust side, a groove will exist on one of the top half or bottom half. In regards to claim 8: Hofbauer teaches at least one cylinder liner (102) disposed in the at least one cylinder; and wherein the lubrication groove is shaped and arranged to direct oil droplets toward at least one portion of the at least one cylinder liner, wherein during operation the oil droplets will be scraped in a direction along the piston wall and towards the upper portion of the cylinder liner. In regards to claim 9: Hofbauer teaches the lubrication groove is shaped and arranged to direct oil droplets toward an exhaust side of the at least one cylinder liner, wherein Hofbauer teaches grooves in two diagonally opposite quadrants when viewed from a top down vantage point as shown in Figure 12 of Hofbauer, wherein if a left half or right half is the exhaust side, a groove will exist on one of the left half or right half, or wherein if a top half or bottom half is the exhaust side, a groove will exist on one of the top half or bottom half. In regards to claim 10: Hofbauer teaches the lubrication groove is sloped at an angle relative to the exhaust side of the at least one cylinder liner, wherein the exhaust side is comprised of an infinite number of points and will always have a slope, including a slope of zero, when a connecting line is drawn from the lubrication groove to any point located on the half of the engine that pertains to the exhaust side of the engine. Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Hofbauer and Kobayashi as applied to claim 4 above, and further in view of Curtis et al (US 2019/0323557 hereinafter “Curtis”). In regards to claim 5: Hofbauer does not teach the at least one cylinder insert is formed from a hardened plastic Curtis teaches a cylinder insert made of a hardened plastic (Paragraph [0003] recites a cylinder insert (liner) made of a plastic, wherein the plastic materials used are defined in Paragraph [0022]). It would have been obvious to one of ordinary skill in the art at the time of filing of the application to modify the cylinder insert of Hofbauer to be formed from a hardened plastic as taught by Curtis in order to improve the wear and fatigue property of the cylinder insert (Paragraph [0013] pf Curtis). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to JAMES JAY KIM whose telephone number is (571)270-7610. The examiner can normally be reached M-F 9-5 EST. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Logan Kraft can be reached at (571) 270-5065. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /JAMES J KIM/Examiner, Art Unit 3747 /HUNG Q NGUYEN/Primary Examiner, Art Unit 3747
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Prosecution Timeline

Jan 14, 2025
Application Filed
Jan 27, 2026
Non-Final Rejection — §103 (current)

Precedent Cases

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
70%
Grant Probability
97%
With Interview (+27.1%)
2y 4m
Median Time to Grant
Low
PTA Risk
Based on 665 resolved cases by this examiner. Grant probability derived from career allow rate.

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