Investigation of water/steam direct injection on performance and emissions of two-stroke marine diesel engine

ABSTRACT

Water/steam direct injection is an effective method to lower emissions and improve the power of engines by using waste heat recovery (WHR). The parameters of water injection (WI) and steam injection (SI) were analyzed at compression stroke on the effect of brake power and emissions in marine engines, including injected timing, mass, and temperature. The results demonstrated that NO_x emissions were substantially reduced by using WI method. However, brake power was also decreased. The SI method not only decreased NO_x emissions but also improved brake power. The NO_x emissions were ascended with increasing temperature and delaying injected timing of water. Opposing trends were found for SI method. The injected mass has a large effect on power and emissions compared with the influence of temperature and timing. The NO_x emissions can be reduced by 72.8% with 2.08% power loss when the 20 g of water was injected into the cylinder at −50 °CA, 15 bar and 400 K. The NO_x emissions can be reduced by 38.9% with 24.7% power improvement when the same mass of superheated steam with 500 K of temperature was injected into the cylinder. It can be obvious that SI method can increase power while reducing fuel consumption and emissions.

KEYWORDS:

• Water injection
• steam injection
• waste heat recovery
• emissions
• marine diesel engine

Declaration of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This work was supported by Science and Technology Planning Project of Ningbo under [Grant 2019B10111]; and Natural Science Foundation of Hebei Province under [Grant E2020202017].