Assessment of a Direct-Injection, Spark-Ignited, Hydrogen-Fuelled Heavy-Duty Engine

Hydrogen-fuelled internal combustion engines (ICE) offer a zero-carbon fuel option for many ICE applications. As part of a global interest to characterise and study the behavior of hydrogen fuel in existing ICE applications Ricardo is collaborating with the University of Brighton to test hydrogen fuel in a Ricardo designed Proteus single cylinder engine. The engine is representative of a 13 litre Euro VI heavy duty (HD) production application converted to run on hydrogen fuel with minimal changes. The engine is fitted with a 35-bar direct injection (DI), hydrogen injector which gives improved flexibility for injection strategies and greatly reduces the presence of hydrogen in the intake system compared to a PFI system. Steady-state testing was carried out at an array of speed load points covering a large part of a typical heavy duty (HD) drive cycle area. An extract of the test results are shared and discussed in this paper. Lambda (λ) sweeps show the system is capable of running out to values exceeding λ = 5.0, exhaust gas recirculation (EGR) sweeps show over 40% EGR can be tolerated at given lambda conditions. Abnormal combustion events present sizeable challenges at lower lambdas due to very large knocking pressures and pre ignition risks. The lambda-threshold where the majority of these events are observed increases with speed and load thus narrowing the initial operating range of the engine prior to introducing mitigating measures like cooled EGR. The basic impact of lambda, EGR, injection and ignition timing sweeps are presented in this paper and show how the system responds to the corresponding changes in specific heat capacity, mixture preparation, and combustion phasing.