Granted Patent
Utility
US 4,249,382 · App. 05/908,414
Exhaust gas recirculation system for turbo charged engines
Inventors:
Duane E. Evans, William Brown, Roger W. Johnson
Patented Case
View Patent ↗
Granted: Feb 10, 1981
Filed: May 22, 1978
Inventors
Duane E. Evans
William Brown
Roger W. Johnson
Assignee (at issue)
Caterpillar Tractor Co.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.