| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a gas measurement method configured to prevent deviation from the emission of a gas calculated by CVS method.SOLUTION: A gas measurement method includes: measuring an exhaust gas volume flow rate Vextl of an engine 23, and exhaust gas component concentrations COd, COd, THCd, NOd; and multiplying the exhaust gas volume flow rate Vextl of the engine 23 by the exhaust gas component concentrations COd, COd, THCd, NOd, to calculate modal mass emission mX. The gas measurement method includes the steps of: calculating a gaseous molecular weight M' of the exhaust gas in a critical nozzle 32, and a specific heat ratioκ'; calculating a flow rate coefficient Cof the exhaust gas component in the critical nozzle 32, by use of the calculated gaseous molecular weight M' of the exhaust gas and the specific heat ratioκ'; and multiplying the calculated modal mass emission mX by a ratio between the flow rate coefficient Cof the exhaust gas component and a flow rate coefficient Cof the air, to correct the modal mass emission mX.</p> |
