Patents by Inventor William M. Ehrhardt

William M. Ehrhardt has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Selective ignition timing
    Patent number: 4243007
    Abstract: An ignition system for spark-ignited internal combustion engines that measures the octane requirement of individual cylinders and optimizes the spark advance timing of the individual cylinders.
    Type: Grant
    Filed: March 26, 1979
    Date of Patent: January 6, 1981
    Assignee: Shell Oil Company
    Inventors: William M. Ehrhardt, Earl J. Haury