Effect of the diesel injection strategy on the combustion parameters of a diesel-hydrogen mixture in a compression-ignition engine at a high hydrogen energy share

This study investigated the effect of diesel injection strategies on combustion in a compression-ignition (CI) engine operating in the hydrogen-diesel dual-fuel mode. Experiments were conducted on a single-cylinder engine at a constant torque of T = 23 Nm and an engine speed of n = 1500 rpm. Dual-fuel combustion, with a hydrogen energy share of EH2 = 67%, was compared with conventional diesel-only operation. To assess the potential for controlling the combustion process under dual-fuel conditions, four diesel injection strategies were investigated. In-cylinder pressure traces, averaged over 100 consecutive engine cycles, were used to analyse the heat release rate, in-cylinder temperature and pressure, and the maximum pressure rise rate. Modifying the diesel injection strategy enabled a stable dual-fuel engine operation while avoiding excessive in-cylinder pressure-rise rates and the associated knock-like combustion.