Issued Patents 1997
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5666923 | Hydrogen enriched natural gas as a motor fuel with variable air fuel ratio and fuel mixture ratio control | Robert Kirk Collier, Jr., Robert L. Hoekstra, Douglas Edward Hahn | 1997-09-16 |
| 5660602 | Hydrogen enriched natural gas as a clean motor fuel | Robert Kirk Collier, Jr., Robert L. Hoekstra, Douglas Edward Hahn | 1997-08-26 |