This project is required to carry out power-reduction and energy-saving transformation of the main engine of a container ship that has been in operation for more than 17 years to meet the requirements of low-speed sailing of ships in the current sluggish shipping market.
For the first time, this project conducts research on power reduction and energy conservation based on actual needs, analyzes its energy-saving potential and corresponding configuration adjustments, customizes the technical implementation plan suitable for the transformation of the ship's main engine, and customizes the "rated power reduction technical transformation" of the ship's main engine. The equipment allocation plan was applied to the energy-saving transformation of the real ship, and good results were achieved.

1. Main research contents of the project:
   Analyzing the working process of a marine two-stroke low-speed diesel engine through numerical simulation calculation method can provide necessary basis for the transformation of marine main engines. Using the powerful computing power of the computer, the thermal working process and injector matching characteristics of the marine two-stroke low-speed diesel engine 6S60MCMK5 were systematically simulated. On this basis, the performance of the diesel engine with variable rated power point was calculated to study the effects of compression ratio, valve timing, and air volume on performance of the diesel engine after the rated power point was revised to achieve a better fuel consumption rate. The feasibility of the turbocharger matching test was also studied. It lays the foundation for independent modification and performance allocation of marine two-stroke low-speed diesel engines, including: performance optimization design of low-speed diesel engines; injector matching technology; and implementation of supercharger allocation tests for trial flights.
2. The main innovations of this project's achievements are as follows:
   1)Optimization design technology for low-speed engine reconstruction and allocation. A numerical model suitable for 6S60MC MK5 diesel engine was established and applied to the optimization design of low-speed engines, with remarkable results.

2. According to the changes in the combustion chamber, the cooperation between the injector and the combustion chamber was analyzed, and a new injector suitable for this project was selected, which improved the combustion state and reduced the fuel consumption rate.
3. High-efficiency supercharger was selected and used in the renovation of low-speed engines of old ships. Taking advantage of the combined operation characteristics of two-stroke low-speed engines and supercharger, a supercharger matching test was carried out for the first time in China during the trial voyage, achieving the research goal.
4. This project has applied for 3 invention patents, 2 of which have been authorized, and 1 paper has been published.
   The results of the project have been applied in container ships of a shipping company. The voyage fuel saving rate has reached 15.6%, the annual savings have been 7.008 million yuan, and the customer's return on investment period is less than 1.5 years.

3. technical indicators

1. The exhaust temperature in front of the main engine turbine is lower than 400℃;
2. Auxiliary fans at common power points do not operate;
3. The fuel consumption rate of the main engine is reduced by more than 5%;
4. The cost recovery period for energy-saving renovation is less than 2 years.