Study On Design Technology Of Injection Control System For Marine LPG Engine

The marine engine fueled with LPG, CNG and LNG and other gas fuels is one of the effective technological measures to reduce emission pollution and improve energy structure of marine power plant. According to technical characteristics of marine gasoline engine power plant, the theoretical research, engineering design and testing methods and other aspects for marine LPG engine injection control system are researched. The main research contents are as follows:1. The universal injection control system for marine LPG engine is designed, which can meet the gas fuel refit requirements of marine electronic injection gasoline engine and carburetor gasoline engine. To execute effectively this solution, the integrated development platform of electronic control system is designed with the core of TMS320F2812 microprocessor, which realizes the synchronous design of software and hardware of electronic control system, and improves the quality of electronic control software.2. The marine LPG engine operating condition judgment, hybrid fuzzy-PID air fuel ratio control algorithm, injection MAP based on BP neural network identification technique and marine LPG engine fuel switch strategy are comprehensively carried out, and the modeling LPG injection control software developed in MATLAB-DSP software environment achieve the strict control of air fuel ratio at overall engine conditions.3. The marine LPG engine model is established, which realized the simulation of LPG fuel influence for intake manifold dynamic and air-fuel ratio estimation. The real-time simulation model of marine LPG engine is established by the discrete similarity method, which achieve time division multiplexing simulation for marine LPG engine model. A virtual modeling technology for inner variables is proposed to a certain degree to solve problem in conventional models that are determined from the data measured on the test bench.The simulation results show that LPG engine model can reflect the performance of gas engine, at the same time calculation precision and speed meet the requirement of control analysis.4. The testing plan of marine LPG engine injection control system is established. The unit software testing methods and integration software testing methods for modeling marine LPG engine injection control software are proposed, and the model in the loop testing results show that theses injection control software testing methods are feasible and effective.The hardware in-the-loop simulation testing platform is established based on PCs, which meets the real time simulation requirement for marine LPG engine model, and provides a good virtual test environment for injection control system performance verification.5. The start test, fuel switch control test and idle condition emission test are carried out on the LPG engine test bench, and a preliminary control performance assessment for the marine LPG engine injection control system are made. The bench test results show that injection control system can meet expected control function; The hybrid fuzzy-PID control algorithm achieves the air-fuel ratio control successfully in the idle conditions, and the emissions meet the Q/711 J127-2001 and GB18285-2005 emission standard; Considering the marine LPG engine conversion speed fluctuation, pollutant emissions and the extent of conversion operations, the acceleration switch control algorithm is better than the direct switch control strategy and deceleration switch control strategy.