Beloved husband, father and grandfather, C. Lyle Cummins Jr., passed away on January 29, 2023, in Wilsonville, Oregon at age 92. He follows his wife of 71 years, Jeanne Cummins, who died in July of 2022. Lyle leaves a legacy of outstanding work in his field as engineer, inventor, author and a model of service, commitment, and love for members of his family.

Born in Columbus, Indiana in 1930 and son of the Cummins Engine Company founder, Clessie Lyle Cummins, Sr., Lyle lived with engines his entire life. A brilliant mind, he contributed numerous innovations to the field of engineering. Graduating with a Bachelor of Science degree from Stanford University in civil engineering, he began his career as structural engineer in San Francisco. He returned to Stanford, earning a Master of Science in mechanical engineering.

Soon after, Lyle began working for his father, Clessie Cummins, during the concept and proof of concept of what would become the "Jake Brake" and the hydrometer fuel system. He went on to become the Senior Product Engineer for Jacobs Manufacturing Company after Jacobs took on the manufacturing rights to the projects. The Jake Brake was later designated a National Historical Mechanical Engineering Landmark by the American Society of Mechanical Engineers/ASME. Lyle received 5 United States and foreign Patents on Diesel fuel systems, along with engineering and marketing the fuel system developed with his father.

Lyle taught as an assistant professor of Mechanical Engineering at the University of Portland. An interest in the history of engineering technology led to his work as an author and popular speaker in the diesel history world.

Two of his works as a writer and publisher, Internal Fire: The Internal Combustion Engine 1673-1900, and Diesel's Engine: Vol 1, From Conception to 1918 were selected as "outstanding academic books" in the history of technology by Choice (Jour. Am. Library Assoc.). He won the ASME 1989 Engineer Historian Award, was recognized as the 1985 Sir Dugald Clerc Award winner, and was a Fellow of SAE, Society of Automotive Engineers, (Class of 1995).

In his later years, Lyle was a huge supporter and driving force behind the Cummins Heritage Center, preserving, and shaping the stories and history of Cummins as a company.

A Memorial service is planned for April 15, 2023 at the Lake Grove Presbyterian Church.