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In accordance with the existing equipment of the laboratory, a multi-cylinder engine cylinder pressure acquisition and combustion analysis system, the system consists of a data acquisition system, engine cylinder pressure data acquisition and combustion analysis software. Dynamometer-based information is an important means to study the process of the engine cylinder. Finishing measured indicator diagram has been calculated indicated work can be obtained, such as indicated mean effective pressure, the maximum combustion pressure and its corresponding crank angle, the maximum rate of pressure rise and its corresponding crank angle, mass fraction burned, heat release rate physical quantities available for further analysis and reveal the engine cylinder combustion process. The rapid development of computer hardware technology has a profound impact on the development of modern cylinder pressure data acquisition system, high-resolution, high acquisition rate, multi-channel, no difference and the sampling frequency can be set arbitrarily, A / D board and a large number of performance superior test instrument angle signal generator, charge amplifier, industrial computer. Cylinder pressure data, the data acquisition system used the four Swiss Kistler produced 6117A46 type spark plug cylinder pressure sensor, four-cylinder simultaneous acquisition and analysis of each cylinder of the engine combustion condition is very convenient. In order to ensure the normal work of the high-speed data acquisition system to reduce the systematic error of sampling channels, a the consistency calibration method of sampling channels. Motored engine to determine the top dead center position in the dynamic, accurate baseline information for combustion analysis. Consider the interference signal of the laboratory, and to take appropriate measures to reduce the impact of this hardware, software. Using Visual C 6.0 independently developed the engine cylinder pressure data acquisition and combustion analysis software. The software under the guidance of the software engineering, object-oriented programming ideas throughout the development process. The software interface is designed to be simple and easy to operate, independent modules facilitate the further expansion of the function. 8 channels can be set by software acquisition on TDC signal and crank angle signal, 1-4 cylinder pressure signal, leaving two spare channels. Calibration processing and a series of smoothing processing of the data collected through the cylinder pressure data can be drawn out of the indicator diagram of the four-cylinder, four-cylinder phase diagram, the rate of pressure rise in FIG mass fraction burned, etc. FIG. Experimental collected BN491DQ engine ignition advance angle corresponding to the different oil temperature (20 ℃, 30 ℃, 40 ℃) (0oBTDC, 6oBTDC 12oBTDC) cylinder pressure data, cold-start emissions, ignition advance angle, changes in the combustion cycle, intake system differences cold start in-depth study. Preliminary study of lean-burn conditions, adjusting the maximum pressure of the fuel injection pulse width cylinder, the highest rate of pressure rise, and the corresponding changes in the crank angle, and significantly reduced emissions of CO, NOx, and, HC emission elevated in the excess air factor is greater than 1.3. Based on the above experimental study, and put forward some recommendations to improve the engine structure and technology development direction.
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