For measuring the oil consumption in an engine, the Non Dispersive Infrared Red Analyzer method (NDIR) and the Flame Photometric Detector method (FPD) are used in general. However, these methods have some problems of the low detection-limit and the inhibition caused by NOx in the exhaust gas. We integrated a new detection method with enzyme, chemiluminescence and the flow injection analysis (FIA), and developed a continuous high-sensitivity exhaust SO₂ analyzer which detects SO₂ at a ppb level and is not inhibited by exhaust gas. First, SO₂ in the exhaust gas was trapped in water by a gas/solution exchanging membrane. Second, the immobilized sulfite oxidase used for a specific catalyst produces H₂O₂ by oxidation of SO₃^2-, and finally determined by peroxyoxalate chemiluminescence.

This method made it possible to measure the change of an exhaust SO₂ at LA-4 mode in real-time with no inhibition in a gasoline engine. Also we measured the oil consumption in a diesel engine. As a result, our method proved be useful for measuring the oil consumption. This new method is expected to apply not only to the support for engine development but also to the measurement of environmental factors including specific gas composition.

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