| In today’s world, the automobile has become the essential part of people’s daily life, thediesel engine for its high efficiency and environmental protection advantages, occupying aconsiderable proportion of the internal-combustion engine market. In such a background,energy saving, environmental protection and efficient two-stroke opposed piston diesel engineemerge as the Era require.Based on reading the traditional structure of diesel engine fuel injection combustionperformance related literature works, carried out numerical simulation study of the cylinderworking process of opposed piston diesel engine (opposite piston engine, OP).This papermake the left cylinder of opposed piston opposed cylinder diesel engine as the research object,a complete and reasonable three-dimensional model was established, use AVL-Fire softwareto simulate calculation part of the combustion parameters of the prototype. The Simulatedvalues agree well with the measured values, the experimental results of the maximumpressure value is15.8MPa, the maximum pressure value of simulation result is16.59MPa,error rate is5.03%, the maximum error of the internal pressure of the cylinder is less than10%, meet the requirement of accuracy, which verifies the correctness of the model. Knownby simulation that injection angle, fuel injection advance angle and combustion chamberdiameter to depth ratio have a great effects of the piston of diesel engine’s combustionperformance, optimization of combustion parameters is the effective means to improve thecombustion; On this basis, further conducted research of the effects of fuel injection angle,injection advance angle and combustion chamber diameter depth ratio on the combustionperformance, obtained the influence law of parameters for this type diesel engine combustionperformance and the performance is optimal parameter combination. Specific content as follows：1) The effect of the different spray Angle and injection hole number to improve oil andgas mixture are analyzed, the results show that: Reasonable injection angle, nozzle holenumber and non-interference in the oil is conducive to the transformation between the jetenergy and turbulent kinetic energy, and thus improve the mixing effect of oil and gas. In eachoil hole size unchanged, a hole injection scheme has shown to work better than the two holeand three hole scheme, but the rate of pressure rise is too high and the NO emissionperformance. Considering the work performance, emission performance and structure strengthindex, scheme3is more suitable for injection angle.2) After the type opposed-piston engine fuel injection advance Angle on the combustionand emission performance of study show: opposed piston diesel engine fuel injection advanceangle should not be too big or too small, should be controlled in10°CA～15°CA. Thevariation range of single cylinder power within this interval is98kw～283.3kw.3) In guarantee of the same compression ratio, depth ratio of combustion chamberdiameter of internal combustion engine power performance and emission performance ofsome effects are studied. Conclusion: combustion chamber diameter to depth ratio ondynamic performance and emission characteristics of internal combustion engine has asignificant impact. With the increased of from3.2to5.3, the piston of diesel engine cycleindicated work is reduced from5093J to1764J, decreased by65.4%. With the increased offrom5.3to6.7, the diesel cycle indicated power increases from1764J to5189J, powercapacity increased by66%; In addition, ratio of diameter to depth affect the combustionchamber ignition delay period and in cylinder gas distribution, and then affect the generationof pollutants. With the ratio of diameter to depth decreases, that says the combustion chamberdeepened, NO generation region near the wall of combustion chamber from the center shiftslightly, and the Soot emissions decreased significantly. |
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