Work

Synergistic effects of intake conditions on performance and emissions in an ammonia-diesel dual-fuel engine

Year: 2026

Type: article

Abstract: Despite growing interest in ammonia/diesel dual-fuel engines, the coupled effects of intake parameters on combustion stability and high-global-warming-potential N 2 O emissions remain insufficiently understood. This study systematically investigates the impact of intake conditions on performance and emissions to propose an optimized control strategy. Using an experimentally validated 3D-CFD model integrated with a detailed chemical kinetic mechanism, the study covers intake temperatures of 335–375 K, intake pressures of 173–213 kPa, and ammonia energy shares of 15–60%. Results show that increasing intake temperature effectively reduces unburned NH 3 and total greenhouse gas emissions by promoting N 2 O decomposition, while incurring only a minor penalty on gross indicated thermal efficiency and gross indicated mean effective pressure, respectively, across all fuel combinations. However, it leads to a notable increase in NO emissions (up to 32.8% at D85A15). Conversely, lowering intake pressure effectively suppresses unburned NH 3 and N 2 O formation while maintaining lower NO levels, albeit with a moderate efficiency loss (gross indicated thermal efficiency decreases by ∼3.28 percentage points for D40A60 when pressure drops from 213 kPa to 193 kPa). In contrast, increasing intake pressure significantly enhances gross indicated thermal efficiency and gross indicated mean effective pressure, but at the cost of higher N 2 O and unburned NH 3 emissions. Therefore, a coordinated strategy of moderately increasing intake temperature while reducing intake pressure is proposed. This approach balances the trade-off between greenhouse gas reduction and NO x control, achieving substantial emission reductions with minimal impact on engine performance, thereby offering a feasible pathway for enhancing environmental performance.

Source: Thermal Science and Engineering Progress

DOI: 10.1016/j.tsep.2026.104865