Hydrogen/Diesel Combustion Analysis in a Single Cylinder Research Engine

The application of an alternative fuel such as hydrogen to internal combustion engines is proving to be an effective and flexible solution for reducing fuel consumption and polluting emissions from engines. An easy to use and immediate application solution is the dual fuel (DF) technology. It has the potential to offer significant improvements in carbon dioxide emissions from light compression ignition engines. The dual fuel concept (natural gas / diesel or hydrogen / diesel) represents a possible solution to reduce emissions from diesel engines by using low-carbon or carbon-free gaseous fuels as an alternative fuel. Moreover, DF combustion is a possible retrofit solution to current diesel engines by installing a PFI injector in the intake manifold while diesel is injected directly into the cylinder to ignite the premixed mixture. In the present study, dual fuel operation has been investigated in a single cylinder research engine. The engine run at two engine speeds (1500 and 2000 rpm), and hydrogen has been injected in the intake manifold in front of the entrance of the tumble intake port. The aim of the study is to compare the DF hydrogen combustion with the DF methane combustion. Premixed ratio up to 92 and 83 has been realized with methane and hydrogen, respectively. In-cylinder combustion pressures and pollutant emissions have been analysed. Finally, cycle resolved optical diagnostics have been applied to detect visible and infrared images from the combustion chamber.