Control method of exhaust waste heat recovery system of marine engine

Abstract

The invention discloses a control method for an exhaust waste heat recovery system of a marine engine, comprising a working medium box, a working medium pump, an evaporator, an exhaust three-way control valve, a preheating control valve, a work control valve, and a piston expander , Cooling and heat dissipation devices, condensers and connecting pipelines, etc. The working medium pump draws the working medium in the working medium tank through the connecting pipeline, and transports it to the working medium inlet of the evaporator. The liquid working medium flowing into the evaporator absorbs the exhaust heat of the marine engine through the principle of heat exchange to form superheated steam. The superheated steam first preheats the expander through the opened preheating control valve, so that it can quickly enter the state of preparation for work. When the expander meets the set working conditions, the preheating control valve is closed, and the work control valve is opened at the same time, so that the superheated steam pushes the expander to do work. The exhausted steam after the work done by the expander will enter the condenser, and the exhausted steam cooled by heat exchange will condense into low-temperature liquid water, and finally return to the working medium tank. In this way, exhaust waste heat can be recovered reasonably.

Description

Technical field [0001] The present invention relates to the engine field, particularly a control method of an exhaust gas reduction heat recovery system for a marine engine. Background technique [0002] The recycling technology for the engine exhaust waste heat energy is mainly divided into thermoelectric conversion, Langken circle, power turbine technology, etc. The reason why the remaining heat recovery of the Langken cycle is first to extract the working medium from the workspace through the electric pump, and is sent to the evaporator, and then use the heat exchange principle to convert the engine high temperature exhaust heat through the evaporator to heating. The heat of the working medium, the heated working medium will form superheated steam, superheated steam, by pushing the expander, making it external or power generation. The inflate of the expander will enter the condenser and return to the working case after the liquid works. [0003] Langken cycles can be divided i...

AI Technical Summary

Problems solved by technology

Such a high temperature may cause the decomposition and failure of the organic working medium, which restricts the application of the organic Rankine cycle in the recovery of high-temperature exhaust heat from the engine

[0007] 2) In addition, other characteristics of organic working fluids (such as acquisition routes, human contact and injury, etc.) also limit the scope of its application

This scheme will result in a part of engine exhaust waste heat not being well utilized

[0010] 5) Most of the solutions in the prior art use the engine speed sensor and throttle sensor to identify the current operating state of the engine, but this method cannot accurately evaluate the impact of changes in other engine parameters on the current operating conditions

[0012] 1) The technical solution does not set an exhaust bypass passage, and when the exhaust energy of the marine engine exceeds the heat exchange capacity of the evaporator for a long time, the evaporator will be damaged;

[0013] 2) The exhaust outlet of the evaporator is not equipped with an exhaust outlet temperature sensor, which leads to the need to design the evaporator model in the waste heat recovery control strategy so that the temperature of the exhaust outlet can be calculated

However, due to the problems of real-time control and model calculation speed, the evaporator model cannot be designed too accurately, otherwise the necessary data will not be obtained in time for the calculation of heat transfer;

[0014] 3) Since marine engines of different powers need to be matched with evaporators of different sizes, it is necessary to parameterize and match different evaporator models, and the parameterization work is more complicated, and a large number of experiments are required to verify the parameterization of the evaporator model Therefore, parameterizing different evaporator models will lead to an increase in development costs, and it is difficult to ensure the consistency of heat transfer capacity throughout the product life cycle

[0018] 3) In the prior art solution (utility model patent CN207813708U), no exhaust outlet temperature sensor is set

[0019] 4) In the existing technical solutions, the method of only using the engine speed sensor and throttle sensor to identify the current operating state of the engine and predict the exhaust energy of the engine for waste heat recovery control is obviously not enough to accurately judge the entire exhaust heat recovery system. state and accurately calculate the waste heat recovery energy

Images