Experimental investigation into transient operating strategies of a turbocharged lean-burn hydrogen ICE and comparison to diesel performance

Abstract Hydrogen fuelled internal combustion engines (H 2 -ICEs) are a promising zero-carbon propulsion solution. Although their steady-state performance has been investigated widely, sufficient transient performance is still challenging, especially for lean-burn, turbocharged configurations. This paper presents an experimental investigation into the transient behaviour and identifies key parameters for engine response and emission behaviour of a lean-burn turbocharged H 2 -ICE. The engine control unit features dedicated strategies for transient operation: an acceleration enrichment function that temporarily allows a richer $$\lambda$$ hence more fuel mass to improve engine response and an ignition retard function to mitigate combustion anomalies. Both functions are activated based on the difference between requested and calculated actual torque. These functions were the enabler to create calibrations with different transient performance. Besides known Non-Road Transient Cycle and World Harmonized Transient Cycle the transient performance was evaluated using a custom test cycle consisting of load steps at various engine speeds. The engine response time from the beginning of the load step until 70% of the full load torque was reached—the t 70% —was used as a key metric. The results highlight the trade-off between fast torque response and emission control and demonstrate the importance of transient engine control. Especially the difference to diesel transient performance shows the need for further development. All tests were conducted within the COMET Research Project Hylley.