The Investigation of Hydrogen-Based Vehicle Propulsion Systems at FKFS and IFS

Abstract:

The defossilisation of transport is of central importance for meeting global climate targets. In addition to introducing battery-electric vehicles that today are mainly intended for individual and local passenger transport， fuels based on renewable resources offer the possibility of fulfilling energy-intensive transport tasks with low global greenhouse gas emissions. Hydrogen produced from renewable energy is gaining particular importance here， as its use in mobile applications ensures not only overall low global warming potential but also the lowest tailpipe greenhouse gas emissions.In this paper， the various aspects of the use of hydrogen in vehicles are briefly presented and the work at FKFS and IFS is illustrated using the development of an H₂-DI combustion process for ICE applications as an example.The presented FVV research project investigates a high-pressure direct injection concept on a single-cylinder passenger car engine test bench. It aims to operate a spark-ignited engine near stoichiometric conditions to produce a significant power output with low boost pressure demand. However， for a hydrogen engine， a stoichiometric mixture leads to an increased knocking tendency towards higher loads. To avoid pre-reactions in the end gas， the injection starts shortly before TDCF and the hydrogen jet is ignited by the spark plug. The injection duration and therefore the maximum hydrogen mass flow through the injector nozzle influence the combustion duration. Challenges of the investigated hydrogen combustion process are， among others， the higher NO_X emission level compared to the lean operation and the hydrogen slip into the exhaust system.

Key words:hydrogen;internal combustion engine;direct injection;stoichiometric combustion