Hydrogen gas natural gas mixed fuel engine optimizing method

Abstract

Disclosed is an optimizing method for a hydrogen and natural gas mixed fuel engine, which belongs to the hydrogen and natural gas mixed fuel engine technical field. The invention aims to effectively discover three control variables, including the optimum hydrogen mixing ratio, ignition advance angle and the excess air factor under each operating condition and obtain the optimum comprehensive performance of the engine. The rotation speed and the torque are used for determining the operating condition point; the three-dimension state space of the hydrogen mixing ratio, the ignition advance angle and the excess air factor is determined under the operating condition point; based on the method of experimental design, the most representative point is selected for the experiment; the data is acquired after the experiment; the points in the data are used for establishing the engine error backward neural network model; namely, the relation of the control variables of the hydrogen mixing ratio, ignition advance angle and the excess air factor, and the economical exhaust is established; the model data is exported and the genetic algorithm is adopted to optimize the engine control parameters; finally, the control variables of optimum hydrogen mixing ratio, the ignition advance angle and the excess air factor of the engine are acquired under the operating condition so that the optimum engine performance is obtained.

Description

technical field [0001] The invention relates to an optimization method for a hydrogen-natural gas mixed fuel engine, and belongs to the technical field of natural gas hydrogen-mixed fuel engine. Background technique [0002] Hydrogen-mixed natural gas fuel is referred to as HCNG, also known as Hythane (hydrogen), which is an alternative gas fuel obtained by mixing hydrogen and natural gas in a certain proportion. It combines the respective advantages of hydrogen and natural gas: 1. The combustion speed of hydrogen is high, about 8 times that of natural gas. Adding hydrogen to natural gas can increase the combustion speed of the mixture, and the ignition can be closer to the top dead center of the engine, reducing compression Negative work, increasing the constant volume of combustion can improve thermal efficiency; 2. The combustible mixing limit of hydrogen is wide, and the lean combustion limit reaches 0.068 (relative fuel-air ratio); the quenching distance is only 30% of ...

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Problems solved by technology

[0006] Since the three control variables hydrogen doping ratio, excess air coefficient and ignition advance angle have a coupling relationship on engine economy and emission, it is a three-variable multi-objective optimization problem. If there is a large amount of experimentation according to the traditional experimental method, and The problem that the optimal control parameters cannot be obtained, so it is necessary to find a new method to solve this problem

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