ASSESSMENT OF TROPICAL AMBIENT CONDITIONS

This study investigates the impact of Nigeria’s tropical environment on the performance of marine diesel engines, focusing on how climatic factors such as air temperature, humidity, atmospheric pressure, and seawater temperature influence engine efficiency Nigeria’s coastal regions are characterized by consistently high temperatures, intense humidity, and seasonal rainfall variations all of which can affect combustion efficiency, cooling capacity, and fuel consumption in marine engines. In this study, an analysis was conducted on the thermodynamic effects of ambient air temperature, humidity, pressure, and seawater temperature on marine diesel engine performance. A simulation framework integrating ISO correction principles with OEM performance curves was developed and applied to model daily and seasonal variations in Nigeria’s tropical environment using meteorological data. The simulated results were validated against manufacturer reference conditions, and based on the findings, technical, operational, and maintenance strategies were proposed to enhance marine diesel engine
efficiency under tropical conditions. Overall, the analysis showed that Nigeria’s tropical climate caused a minor but consistent derating of marine diesel engine performance. Air temperatures between 32–34 °C and humidity above 75 % led to about a 2–3 % reduction in power and a 0.1–0.2 % increase in specific fuel oil consumption compared to ISO conditions. High ambient heat and warm seawater (around 30 °C) reduced air density and charge-air cooling efficiency, resulting in slightly higher fuel flow rates. Despite these effects, the Wärtsilä 8L32 demonstrated stable exhaust temperatures and strong load control, indicating good adaptability to tropical conditions.