Fuel-Saving Control Strategy for Tugboats Based on Multi-Objective Optimization

In response to the conflicting issues faced by tugboats under different operating conditions, where they simultaneously require “high thrust” while aiming for “low fuel consumption and low thermal load operation”, this paper focuses on the tugboat main engine propulsion system. A multi-objective optimization-based fuel-saving control strategy is proposed. The engine speed and cooling water valve opening are used as control variables, and three performance indicators—the thrust output, fuel consumption rate, and diesel engine operating temperature—are considered comprehensively. A multi-objective optimization mathematical model is established, incorporating the tugboat’s main engine thrust model, fuel consumption model, and engine temperature model. An improved multi-objective genetic algorithm (NSGA-II) is introduced to solve the tugboat fuel consumption optimization problem. Through case analysis, the Pareto optimal solution set for the tugboat’s operating conditions is obtained, revealing the trade-off relationships between the thrust, fuel consumption, and temperature under different control variable combinations. The results indicate that this method provides effective control strategy references for tugboat operation under high thrust, fuel-saving, and balanced economic conditions. It has a certain engineering application value for improving the economic efficiency and the safety of tugboats.