Development of in-cylinder injection for a hydrogen-fueled internal combustion engine

Traditional means for converting an engine to operate on hydrogen fuel incorporates port injection. The typical method for controlling emissions on a port injection engine is to operate the engine lean (typical AFR of 70:1) and/or incorporate an EGR system. The result of utilizing these methods is an appreciable reduction in power output. In-cylinder injection of an internal combustion engine provides a reliable method for delivering hydrogen fuel whereby fuel efficiency, power output and emissions levels are improved. Injection of hydrogen directly into the combustion chamber allows control of various factors such as burn rate and combustion timing which influence the production of emissions in the form of NOx. Testing of the converted engines has also shown an increase in power due to an increase in volumetric efficiency and a reduction of emissions at near stoichiometric operation. Details for converting an engine to an in-cylinder hydrogen injection, computer systems control, emissions testing and performance evaluation are given.