Four Stroke Internal Combustion Engine
Explains the strokes of internal combustion engines using animations from the Glenn Research Center.
http://www.grc.nasa.gov/WWW/K-12/airplane/engopt.html

Internal Combustion Engines Web Site
Internal combustion engine. Internal combustion engines. Applets are used to perform simple calculations. Developed at Colorado State University
http://www.engr.colostate.edu/~allan/engines.html

University of Oxford: Combustion in Internal Combustion Engines and Fuel Cells
Conducts research on combustion processes in spark ignition engines, variable valve timing and fuel cells. Includes project summary and contact information.
http://www.eng.ox.ac.uk/ice/

Doshisha University - Spray and Combustion Science Laboratory
Studies combustion processes in internal combustion engines. Includes laboratory information and project descriptions. [English, Japanese]
http://comb.doshisha.ac.jp/

Wikipedia: Internal Combustion Engine
Free encyclopedia article covers internal combustion engine technology and applications. Addresses operation modes, thermodynamic cycle and efficiency, fuel types, support systems and parts.
http://en.wikipedia.org/wiki/Internal_combustion_engine

Mechadyne International
Mechadyne International - Variable Valve Actuation Systems for Internal Combustion Engines - VVA For Performance, Fuel Economy and emissions
http://www.mechadyne-int.com/

Jayson Engineering
Manufacturer of connecting rods for internal combustion engines. Includes company information and product overview.
http://www.jaysonengg.com

Tetik
Manufacturer of valves, guides and seat inserts for internal combustion engines. Includes company profile and product overview.
http://www.tetik.com

Swiss Federal Institute of Technology - Aerothermochemistry and Combustion Systems Laboratory (ACL)
ETH Zuerich
http://www.lav.ethz.ch/index_EN

LO.GAS S.r.l.
sistemi di conversione autoveicoli a GPL METANO LPG CNG/NGV systems for the convertion of vehicles-multivalvole elettrovalvole commutatori riduttori miscelatori multivalves LPG commutator reducer mixer
http://www.lo-gas.com