有限空间柴油车辆耗氧量及尾气污染物分析与计算

Calculation and analysis of the oxygen consumption and exhaust pollutant emission of diesel vehicle in a confined space

针对停放柴油车辆的有限空间环境,对车辆发动机燃料燃烧与有限空间环境空气间的氧气消耗关系、尾气排放与通风控制关系进行了讨论。给出了在有限空间中发动机进气量、耗氧量的计算公式,校核了有限空间中通风供氧量与停放车辆数的关系;给出了车辆发动机尾气排放量的计算公式。通过对有限空间柴油发动机尾气主要污染物组分及浓度与过量空气(氧气)系数关系的分析,得出控制污染物的最小通风量。

This paper is to be devoted to the discussion of the relationship between fuel combustion in the heavy-duty diesel engine and the ambient air ventilation through a theoretical analysis.As is known,the vehicles driven by an internal combustion diesel engine used to be parked in a confined space where diesels consume oxygen,whereas the exhaust contains carbon monoxide,nitrogen oxides,etc.Even in such a narrow limited space,ventilation is necessary to ensure the regular operation of diesels and protect the driver and other people around from the hazards likely to be caused by the harmful pollution.Thus,the above topic has made us feel the urgent need to figure out the best means to minimize the ventilation volume in such a kind of confined space.To achieve the aforementioned research goal,we have first of all worked out the intake volume of the engines itself.And then,calculation has to be done with the amount of oxygen to be consumed in accordance with the actual working condition of the engines.At the same time,it is necessary to work out the excessive air rate by the ratio of intake oxygen volume to the oxygen consumption volume.And,in this way,it is essential to work out the intake volume formula,the oxygen consumption formula,and the excessive air formula,respectively.The results of our investigation and calculation prove that,the intake volume does not vary with the actual working conditions of the diesel engine.However,the excessive air ratio should be decided by the oxygen content of the ambient environment and the oxygen consumption volume of the individual diesel engines.And,the examples of calculating oxygen consumption and excess air ratio show that the number of diesel engines are allowed to be parked in the above said confined space is checked according to the oxygen supply by the ventilation system provisioned by the national code.And,finally,the pollution of the exhaust could be analyzed in accordance with the excessive air ration related to the working conditions of the diesel engines,with the exhaust volume formula being given.With everything ready,the relationship between the pollution compositions and the excessive air ration can be discussed by using NOxas the control index of ventilation.And,in this way,it can be expected to achieve the calculation formula of the least ventilation volume to control the air pollution in the aforementioned confined space.The proofs we have gained have shown the ventilation volume has been found too large for all vehicles in operation,which makes it necessary for them to start their engines separately by two or three batches.