Piston Rings for Internal Combustion Engines

Piston rings are small components with massive responsibility—sealing combustion, managing oil, and minimizing wear. This course provides a deep dive into ring design, materials, coatings, and the complex interactions between rings and cylinder walls. Learners will gain practical insight into wear mechanisms, blow-by and oil consumption mitigation, and advanced measurement and validation techniques used in modern engine development.

• Mechanical and powertrain engineers involved in engine design, testing, or reliability analysis.
• Engineering students, ICE researchers, and enthusiasts seeking advanced knowledge of piston ring systems.
• Professionals in failure analysis, root cause analysis (RCA), or component validation roles.

Module 1: An Introductory Look

Module 2: Ring Design Details

Module 3: Temperature Control and Ring Dynamics

Module 4: Ring Movement and the Cylinder Wall

Module 5: Oil Transfer

Module 6: Ring and Cylinder Wall Wear Mechanisms

Module 7: Wear Rate Validation

Module 8: Measurement and Analysis

Kevin Hoag

Mr. Hoag has over 45 years of experience in diesel and gasoline engine development, in both industrial and academic environments, and is a Fellow of the Society of Automotive Engineers. He holds the position of Institute Engineer, the highest technical level position at SwRI. He is a past chair of SwRI’s Advisory Committee for Research (ACR). Experience is wide ranging and includes both diesel and spark-ignition combustion, engine performance development and emission control, engine layout and balance, casting, forging and materials, structural fatigue analysis, air handling, cooling, and lubrication systems. Experience also includes significant customer interaction, engine application and service, and engineering education.

Mr. Hoag’s primary expertise is in engine thermodynamics, heat transfer and fluid mechanics. He also has significant experience in engine temperature control, engine lubrication and wear. Work experience includes two years in automotive heat exchanger development (Modine Mfg.), 16 years in diesel engine development (Cummins, Inc.), and 14 years in engineering education and engine research (University of Wisconsin), prior to joining SwRI in 2013. Through 2023 he held an appointment at the University of Wisconsin, teaching one graduate engineering course by distance each semester. He was awarded Emeritus status at the conclusion of the Fall 2023 term.

Specific highlights of his technical contributions include development of explicit formulation for Second Law analysis of IC engines; Creation and management of the Heat & Fluids group at Cummins, Inc.; Founding director and lead developer of the Master of Engineering in Engine Systems (MEES) program at the University of Wisconsin.

PATENTS & PUBLICATIONS: Seven patents, two textbooks (Vehicular Engine Design, Springer-Verlag, 2015, and Skill Development for Engineers, IEE Press, 1999), and over 35 technical publications. Engine design editor for the Encyclopedia of Automotive Engineering, John Wiley & Sons, Ltd., 2015.

HONORS & AWARDS: Arch Colwell Merit Award for Outstanding Technical Publication, Society of Automotive Engineers; Two-time recipient of SAE Outstanding Younger Member Award; Elected Fellow of the Society of Automotive Engineers in 2017; Directed group at Cummins that received the inaugural Glen L. Martin Award for Corporate Leadership in Continuing Engineering Education from the International Association for Continuing Engineering Education. Emeritus, University of Wisconsin