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As the main engine on transport ships, effective low-speed engines operating on a fixed-pitch propeller (FPP) with variable speed are most prevalent. The power of the main engine during its work on the propeller curve depends on the external operating conditions and the mode of operation of the propeller. Operational regulation of the power of the main engine during its operation at the FPP is performed by changing the rotational speed (figure 2). In this case, the power produced by the main engine is determined by the consumer of mechanical energy the propeller screw. Fixed pitch propellers are characterized by high hydrodynamic performance in the design mode. When the operating conditions change, their efficiency decreases significantly (figure 1), which affects the power consumption of the main engine. The mutual arrangement of the propeller curves of the engine load (figure 2) is formed depending on the design features and the technical condition of the propeller and the hull, the mode of operation of the vessel, the sailing conditions (changes in draft, depth under the keel, weather conditions). This pattern forms the dependence of the parameters of thermal and mechanical tension of the engine on the operating conditions and significantly limits the operational envelope of diesel engine. In modern studies, insufficient attention is paid to the ability to change the power of the engine at a constant frequency of rotation of the FPP. Analysis of the scientific literature and patent developments showed a significant interest of researchers to the design of the propeller. However, most of the proposed designs have a permanent, unregulated effect on the main engine and cannot be used to control its power at a constant frequency of rotation of the FPP. Figure 1. Screw propeller open water diagram: 1 the coefficient of thrust (K1), 2 moment coefficient (K2); 3 – efficiency (η).

Power control of the engine operating on the fixed pitch propeller