Study For Spark Ignition Characteristics Based On Constant Volume Combustion Bomb Experiment System

Energy conservation and environmental protection have become the two major problems that the internal combustion engine industry must face, also can meet the demand of social and economic sustainable development. Designing and creating an engine with better performance, fuel economy and emission are the main direction of internal combustion engine research workers. Compared to traditional gasoline engine, the combustion process in cylinder of gasoline direct injection engine (GDI) is more complicated. Mixing and burning rate of mixture is the base of studying the combustion process. Constant volume bomb as simulation of an engine working process is the effective method to study the mechanism of combustion process. It can control the boundary conditions of combustion process, simplified experimental work, easy to find out the internal relation of parameters in the process of combustion.Combustion process is not only influenced by the shape of combustion chamber, fuel injection, chemical kinetics, air intake and exhaust system, but also affected by the ignition system. The good or bad ignition characteristics directly affect the combustion process of engine, thus affecting work stability, emission characteristics, fuel economy. In this paper, in order to research the influence of the key parameters of ignition system in the combustion process, constant volume bomb test system is used to study the location of spark plug, excess air coefficient, the structure of the spark plug, spark plug gap on the different ignition energy, for the influence of the maximum combustion temperature, pressure, ignition delay period, laminar flame spread rate. Achieving qualitative analysis of key parameters for the combustion process, it is provided for the basis for optimization matching of the ignition system of GDI engine.The author uses the virtual instrument development platform——LabVIEW to write the data acquisition and combustion analysis program of constant volume bomb test system. It is calculated the maximum combustion temperature, pressure, ignition delay period of combustion process through the cylinder pressure data. At the same time, the author also establishes the analysis method of laminar flame propagation velocity by using MATLAB. The experimental results show that the ignition position has no significant effect on combustion process; For maximum combustion temperature, pressure, only the excess air coefficient influences it, the excess air coefficient= 0.8, the maximum. When the excess air coefficient is 0.9, laminar flame spread rate is fastest; the greater spark plug ignition energy, the ignition delay period is on the decline; spark plug structure is mainly based on the negative comparison, it is discovered that the ignition delay period of BKR5EIX-11 spark plug is the shortest, the laminar flame propagation speed is the fastest. The spark plug gap has no significant effect on combustion process.