19 patents currently held
Held is read from USPTO's recorded assignments; a transfer never recorded there does not appear.
1 more record may belong here and awaits a decision; it is not counted.
The next term ends in Aug 2027. from the record
Free plan: 3 watched companies. Pro: unlimited.
Alerts on its grants, lapses and transfers.
7
Ending by 2030
Aug 2027
Next term end
4
Patent families
When these terms end
Held patents by the year their term ends
notable patents
fee due within 90 days
all others
Updated Nov 14, 2026 · includes USPTO assignment & status data published Nov 14, 2026 and grant & fee data published Nov 10, 2026 (weekly) · how we know
Notable: the highest-ranked patents in this portfolio by citations and family size. Fee due within 90 days: a maintenance fee is due within 90 days of when this page was computed and not yet paid.
Notable patents
Ranked by citations and family size, against patents of the same kind granted the same year. How we rank
Only 2 of the currently held patents qualify as notable.
Notable
Ends May 2031 · High confidence
Also notable
Ends Sep 2043 · High confidence
Isochoric Heat Addition Engines and Methods
US 8,863,724
The most cited patent in this portfolio, cited by 43 later US patents, top 25% of utility patents granted in 2014 in our data. Protection runs to 2031.
Two-Stroke Rotary Engine with Improved Inlet and Outlet Ports
US 12,742,390
Granted 2026. Too new for citation comparison; protection runs to 2043.
Fee deadlines
Maintenance fees fall due 3.5, 7.5 and 11.5 years after grant. A missed fee ends a patent at the end of the six month grace period that follows, not on the due date.
- 1 fee due Apr 3, 2027The maintenance fee for Combination Piston and Piston Ring for Reducing Crevice Volume (US 11,773,974) comes due Apr 3, 2027. Unpaid by Oct 4, 2027, it lapses early.
Recent changes
- 2 of the patents on this record were granted since Aug 16, 2026
What they patent
Grouped by real patent family, largest first, labeled by the earliest filing in each. No technology classification is inferred from titles.
| Hybrid Cycle Rotary Engine | 16 in force | to Jul 2037 |
| Mobile Engine-Generator Vehicle | 1 in force | to Jun 2044 |
| Two-Stroke Rotary Engine with Improved Inlet and Outlet Ports | 1 in force | to Sep 2043 |
| Hybrid Drive and Fuel Vaporizer for UAV and Other Mobile Environments | 1 in force | to Jul 2042 |
Patents held now
Soonest term end first.
| Patent | Title | Status | Expires | Confidence |
|---|---|---|---|---|
| US 8,863,723 | Hybrid Cycle Rotary Engine In force · High confidence | In force | High confidence | |
| US 9,644,570 | Hybrid Cycle Rotary Engine In force · High confidence | In force | High confidence | |
| US 8,365,699 | Hybrid Cycle Rotary Engine In force · High confidence | In force | High confidence | |
| US 7,909,013 | Hybrid Cycle Rotary Engine In force · High confidence | In force | High confidence | |
| US 8,365,698 | Hybrid Cycle Combustion Engine and Methods In force · High confidence | In force | High confidence | |
| US 10,196,970 | Isochoric Heat Addition Engines and Methods In force · High confidence | In force | High confidence | |
| US 9,382,851 | Isochoric Heat Addition Engines and Methods In force · High confidence | In force | High confidence | |
| US 8,863,724 | Isochoric Heat Addition Engines and Methods In force · High confidence | In force | High confidence | |
| US 8,523,546 | Cycloid Rotor Engine In force · Medium confidence | In force | Medium confidence | |
| US 9,353,623 | Seal Assembly for a Heat Engine In force · High confidence | In force | High confidence |
Also on record, not counted in the 19: 4 patents ended · 2 applications pending · 4 applications abandoned. List them
Sources and methods
Compiled from USPTO application file histories, grants and recorded assignments, with the company's own names reviewed by hand. How this record was built
Portfolio grouped automatically from ownership conveyances to the names matched to this company, usually every name that begins with its own, so it counts patents an affiliate holds; each list row names the holder of record. Security interests are excluded and ambiguous records are not reviewed by hand.
Fee due within 90 days marks a patent with a maintenance fee due within 90 days of the date this page was computed and not yet recorded paid, so it can end earlier than the bar shows. A fee left unpaid ends the patent at the close of the six month grace period that follows its due date, not on the due date itself. It is not a prediction that the fee will be missed.
Computed patent terms end on the dates shown. Related patents and pending applications may cover overlapping subject matter.
2 computed term dates come from a chain with an unresolved parent. A continuity parent has not yet been fetched from USPTO's records. The term is dated from this application's own claim; no earlier date is assumed until the parent is resolved.