Patents by Inventor David Lawrence Hasfjord

David Lawrence Hasfjord 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).

  • Maintenance alert system for heavy-duty trucks
    Patent number: RE39845
    Abstract: A real-time maintenance alert system and method for use in a heavy-duty truck having an engine controller with memory are provided. The system includes a sensor operative to indicate an engine condition from the group consisting of: oil filter restriction, air filter restriction, fuel filter restriction, oil level, and coolant reserve tank fluid level. Control logic at the engine controller processes the sensor signal to determine a real-time fault condition, when appropriate.
    Type: Grant
    Filed: June 10, 2002
    Date of Patent: September 18, 2007
    Assignee: Detroit Diesel Corporation
    Inventors: David Lawrence Hasfjord, Richard M. Avery, Jr., Dennis Michael Letang, James A. Gray, Donald M. McDonald, Marleen F. Thompson, Ian Daniel McKenzie, John Edward Longnecker