IP Library Granted Patent US 12,587,118
Granted Patent B2
US 12,587,118 · App. 18/938,165 · Granted Mar 24, 2026

Core synchronization for linear generators

Inventors: Nick Schaeferle (Fremont, CA); Yuk Hei Wong (Santa Cruz, CA); Patrick Gorzelic (San Francisco, CA); Matthew Roelle (Belmont, CA)
Assignee: Mainspring Energy, Inc.
H02P9/105H02K7/1884
View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 12,587,118
App. No.
18/938,165
Granted
Mar 24, 2026
Kind
B2
Abstract

Systems and methods are provided for controlling two or more linear generators each operating according to a repeated behavior to constitute a cycle. A control system utilizes control circuitry to determine a desired phase offset between operation cycles of a first linear generator and a second linear generator of the two or more linear generators. During operation, an actual phase offset between the first linear generator and the second linear generator is determined. The control circuitry of the control system is used to modify the operation of at least one of the first linear generator or the second linear generator to achieve the desired phase effect.

Claims (30)

1 . A method for controlling a plurality of piston assemblies in a generator, the method comprising:

determining, using processing circuitry, a respective phase for each of the plurality of piston assemblies relative to at least one other of the plurality of piston assemblies; and

causing to be modified, using the processing circuitry, at least one operating parameter of the generator based on at least one of the respective phases and on at least one desired phase associated with at least one of the plurality of piston assemblies.

2 . The method of claim 1 , further comprising a plurality of cores that comprise the plurality of piston assemblies.

3 . The method of claim 2 , wherein causing to be modified the at least one operating parameter of the generator comprises causing to be modified that least one operating parameter of the generator to synchronize operation of the plurality of cores.

4 . The method of claim 3 , wherein the at least one operating parameter comprises a respective apex time of at least one of the piston assemblies of the plurality of cores.

5 . The method of claim 3 , wherein the operation of the plurality of cores comprises at least one of a respective frequency of the plurality of cores or a respective phasing of the plurality of cores.

6 . The method of claim 2 , wherein each core of the plurality of cores comprises a respective linear electromagnetic machine (LEM).

7 . The method of claim 6 , wherein each respective LEM of the plurality of cores comprises:

at least one respective translator comprising at least one respective piston assembly of the plurality of respective piston assemblies; and

at least one respective stator that produces a respective electromotive force that acts on the at least one respective translator when the at least one respective translator is in motion.

8 . The method of claim 6 , wherein the respective LEM of at least one of the plurality of cores generates a net electrical energy output over each stroke of the LEM.

9 . The method of claim 1 , wherein the at least one operating parameter comprises at least one of a net electrical energy output of the generator, a position of at least one piston assembly of the plurality of piston assemblies, a rate of flow of air, a rate of flow of fuel, an intake pressure, or an exhaust pressure.

10 . The method of claim 9 , wherein the position of the at least one piston assembly of the plurality of piston assemblies comprises a respective apex position of the at least one of the piston assemblies of the plurality of cores.

11 . A generator, comprising:

a plurality of piston assemblies; and

processing circuitry configured to:

determine a respective phase for each of the plurality of piston assemblies relative to at least one other of the plurality of piston assemblies; and

cause to be modified at least one operating parameter of the generator based on at least one of the respective phases and on at least one desired phase associated with at least one of the plurality of piston assemblies.

12 . The generator of claim 11 , further comprising a plurality of cores that comprise the plurality of piston assemblies.

13 . The generator of claim 12 , wherein the processing circuitry is further configured to cause to be modified the at least one operating parameter of the generator to synchronize operation of the plurality of cores.

14 . The generator of claim 13 , wherein the at least one operating parameter comprises a respective apex time of at least one of the piston assemblies of the plurality of cores.

15 . The generator of claim 14 , wherein the operation of the plurality of cores comprises at least one of a respective frequency of the plurality of cores or a respective phasing of the plurality of cores.

16 . The generator of claim 12 , wherein each core of the plurality of cores comprises a respective linear electromagnetic machine (LEM).

17 . The generator of claim 16 , wherein each respective LEM of the plurality of cores comprises:

at least one respective translator comprising at least one respective piston assembly of the plurality of respective piston assemblies; and

at least one respective stator that produces a respective electromotive force that acts on the at least one respective translator when the at least one respective translator is in motion.

18 . The generator of claim 16 , wherein at least one LEM of the plurality of cores generates a net electrical energy output over each stroke of the LEM.

19 . The generator of claim 11 , wherein the at least one operating parameter comprises at least one of a net electrical energy output of the generator, a position of at least one piston assembly of the plurality of piston assemblies, a rate of flow of air, a rate of flow of fuel, an intake pressure, or an exhaust pressure.

20 . The generator of claim 19 , wherein the position of the at least one piston assembly of the plurality of piston assemblies comprises a respective apex position of the at least one of the piston assemblies of the plurality of cores.

Assignments (2)
SECURITY INTEREST Recorded Jun 6, 2025
From: MAINSPRING ENERGY, INC.
To: AVENUE VENTURE OPPORTUNITIES FUND II, L.P., AS AGENT
Reel/Frame 071499/0428 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 9, 2025
From: SCHAEFERLE, NICK; WONG, YUK HEI; GORZELIC, PATRICK; ROELLE, MATTHEW
To: MAINSPRING ENERGY, INC.
Reel/Frame 069799/0085 →
Continuity (3)
Continuation 18034760
Provisional Application 63109973 · Nov 5, 2020
Related Publication 20250175102A1 · May 29, 2025
References Cited (108)
US 2899565A · Turner · 1959 [cited by examiner]
US 3297007A · Monpetit · 1967 [cited by applicant]
US 3552120A · Beale · 1971 [cited by examiner]
US 4154200A · Jarret et al. · 1979 [cited by applicant]
US RE30176E · Beale · 1979 [cited by examiner]
US 4791786A · Stuyvenberg · 1988 [cited by applicant]
US 4924956A · Deng · 1990 [cited by examiner]
US 5775273A · Beale · 1998 [cited by examiner]
US 6170443B1 · Hofbauer · 2001 [cited by applicant]
US 6181110B1 · Lampis · 2001 [cited by applicant]
US 6293231B1 · Valentin · 2001 [cited by applicant]
US 6652247B2 · Gray, Jr. · 2003 [cited by applicant]
US 6694858B2 · Grimes · 2004 [cited by examiner]
US 6823671B2 · Achten · 2004 [cited by examiner]
US 6948459B1 · Laumen · 2005 [cited by examiner]
US 6971339B2 · Janssen · 2005 [cited by applicant]
US 7721686B2 · Lindgarde · 2010 [cited by applicant]
US 8127544B2 · Schwiesow et al. · 2012 [cited by applicant]
US 8413617B2 · Simpson et al. · 2013 [cited by applicant]
US 8522538B2 · Ingersoll · 2013 [cited by examiner]
US 8997699B2 · Roelle · 2015 [cited by examiner]
US 9470110B2 · Stroganov · 2016 [cited by examiner]
US 9567898B2 · Simpson · 2017 [cited by examiner]
US 9657675B1 · Roelle et al. · 2017 [cited by applicant]
US 9869274B2 · Fuhrman · 2018 [cited by examiner]
US 9885280B2 · Hamann · 2018 [cited by examiner]
US 10024231B2 · Simpson · 2018 [cited by examiner]
US 10156198B2 · Roelle · 2018 [cited by examiner]
US 10202897B2 · Sun et al. · 2019 [cited by applicant]
US 10221759B2 · Simpson · 2019 [cited by examiner]
US 10404199B2 · Da Costa · 2019 [cited by examiner]
US 10408150B2 · Roelle · 2019 [cited by examiner]
US 10472995B2 · Gusev · 2019 [cited by examiner]
US 10715068B2 · Da Costa · 2020 [cited by examiner]
US 10731586B2 · Roelle · 2020 [cited by examiner]
US 10851708B2 · Simpson · 2020 [cited by examiner]
US 10985641B2 · Lawler et al. · 2021 [cited by applicant]
US 11053876B2 · Roelle · 2021 [cited by examiner]
US 11211885B2 · Da Costa · 2021 [cited by examiner]
US 11339735B2 · Roelle · 2022 [cited by examiner]
US 11404937B2 · Svrcek · 2022 [cited by examiner]
US 11421586B2 · Liu · 2022 [cited by examiner]
US 11525391B2 · Simpson · 2022 [cited by examiner]
US 11616428B2 · Lawler · 2023 [cited by examiner]
US 11652432B2 · Da Costa · 2023 [cited by examiner]
US 11831225B2 · Liu · 2023 [cited by examiner]
US 11982186B1 · Freeman · 2024 [cited by examiner]
US 12113427B2 · Manasra · 2024 [cited by examiner]
US 12170501B2 · Schaeferle · 2024 [cited by examiner]
US 12283911B2 · Da Costa · 2025 [cited by examiner]
US 20030121405A1 · Grimes · 2003 [cited by examiner]
US 20050081804A1 · Graf et al. · 2005 [cited by applicant]
US 20060124083A1 · Niiyama et al. · 2006 [cited by applicant]
US 20070007917A1 · Yagi · 2007 [cited by applicant]
US 20080196680A1 · Janak et al. · 2008 [cited by applicant]
US 20090179424A1 · Yaron · 2009 [cited by applicant]
US 20100275884A1 · Gray, Jr. · 2010 [cited by applicant]
US 20110100002A1 · Muir · 2011 [cited by examiner]
US 20110221206A1 · Milinkovic · 2011 [cited by examiner]
US 20120024264A1 · Mikalsen et al. · 2012 [cited by applicant]
US 20120112467A1 · Gopalakrishnan et al. · 2012 [cited by applicant]
US 20120126544A1 · Simpson · 2012 [cited by examiner]
US 20120204836A1 · Roelle · 2012 [cited by examiner]
US 20130082000A1 · d'Artenay et al. · 2013 [cited by applicant]
US 20140238011A1 · Fuhrman · 2014 [cited by examiner]
US 20140373527A1 · Stroganov · 2014 [cited by examiner]
US 20160160754A1 · Moriya et al. · 2016 [cited by applicant]
US 20160208686A1 · Gadda et al. · 2016 [cited by applicant]
US 20170350339A1 · Roelle · 2017 [cited by examiner]
US 20180179918A1 · Gusev · 2018 [cited by examiner]
US 20190063357A1 · Roelle · 2019 [cited by examiner]
US 20190123668A1 · Da Costa et al. · 2019 [cited by applicant]
US 20190149074A1 · Da Costa · 2019 [cited by examiner]
US 20190390623A1 · Roelle · 2019 [cited by examiner]
US 20200036273A1 · Lawler et al. · 2020 [cited by applicant]
US 20200195093A1 · Svrcek · 2020 [cited by examiner]
US 20200328707A1 · Da Costa · 2020 [cited by examiner]
US 20210010437A1 · Roelle · 2021 [cited by examiner]
US 20210288570A1 · Lawler · 2021 [cited by examiner]
US 20210324812A1 · Roelle · 2021 [cited by examiner]
US 20220120214A1 · Liu · 2022 [cited by examiner]
US 20220123626A1 · Liu · 2022 [cited by examiner]
US 20220173682A1 · Da Costa · 2022 [cited by examiner]
US 20220381192A1 · Roelle · 2022 [cited by examiner]
US 20220399784A1 · Svrcek · 2022 [cited by examiner]
US 20230198367A1 · Lawler · 2023 [cited by examiner]
US 20230246576A1 · Da Costa · 2023 [cited by examiner]
US 20240113644A1 · Schaeferle · 2024 [cited by examiner]
US 20240125281A1 · Roelle · 2024 [cited by examiner]
US 20240146152A1 · Manasra · 2024 [cited by examiner]
US 20240297553A1 · Svrcek · 2024 [cited by examiner]
DE 102008030633A1 · 2009 [cited by applicant]
GB 2413825A · 2005 [cited by examiner]
GB 2469279A · 2010 [cited by examiner]
JP 2006170071A · 2006 [cited by applicant]
JP 2012021461A · 2012 [cited by applicant]
JP 2012031746A · 2012 [cited by applicant]
JP 2012202386A · 2012 [cited by applicant]
JP 2012202387A · 2012 [cited by applicant]
JP 2015074308A · 2015 [cited by applicant]
WO WO0123721A1 · 2001 [cited by examiner]
WO 2005100764A1 · 2005 [cited by applicant]
WO WO2009091834A1 · 2009 [cited by examiner]
WO 2014172382A1 · 2014 [cited by applicant]
WO 2017171816A1 · 2017 [cited by applicant]
Hanipah et al., “Recent commercial free-piston engine developments for automotive applications”, Applied Thermal Engineering, vol. 75, Oct. 5, 2014, pp. 493-503. [cited by applicant]
Johansen et al., “Free-Piston Diesel Engine Timing and Control-Towards Electronic Cam- and Crankshaft”, IEEE Transactions on Control Systems Technology, vol. 9, No. 3, Mar. 1, 2002, pp. 1-14. [cited by applicant]
Zaseck et al., “Adaptive control approach for cylinder balancing in a hydraulic linear engine”, 2013 American Control Conference, Jun. 17, 2013, pp. 2171-2176. [cited by applicant]