Method and apparatus for providing diluted gas to exhaust emission analyzer
First Claim
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1. An apparatus for controlling the dilution of an exhaust gas sample from the exhaust system of an engine for analysis by an exhaust emission analyzer, the apparatus comprising:
- an exhaust gas sampling line having first and second ends, said first end being fluidly connected to the exhaust system of the engine;
an exhaust gas sampling line orifice fitted to said exhaust gas sampling line, said exhaust gas sampling line orifice having an inlet;
a source of substantially pollutant-free diluent gas;
a diluent line having first and second ends, said first end being connected to said source of substantially pollutant-free diluent gas;
a diluent line orifice fitted to said diluent line, said diluent line orifice having an inlet, and said exhaust gas sampling line orifice and said diluent line orifice being configured so as to produce equal pressure drops thereacross;
a diluent pressure regulator fitted to said diluent line and connected to said exhaust gas sampling line for controlling pressure such that pressure at said diluent line orifice inlet is equal to pressure at said exhaust gas sampling line orifice inlet;
a diluted gas outlet line having first and second ends, said first end being connected to the exhaust emission analyzer;
a fluid junction, said second ends of said exhaust gas sampling line, said diluent line, and said diluted gas outlet line being connected to said fluid junction; and
means for drawing diluted gas through said diluted gas outlet line.
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Abstract
An apparatus and method are adapted for analyzing exhaust emissions by using a small fraction of a continuously-extracted exhaust sample combined with a pollutant-free diluent through a system of critical flow orifices at a predetermined and precisely controlled flow ratio. A small quantity of gas is extracted from the diluted exhaust gas available which is diluted with the contaminant-free air or nitrogen to produce a mixture having a dew point below ambient air temperature and satisfying the flow requirements of the analysis system.
89 Citations
24 Claims
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1. An apparatus for controlling the dilution of an exhaust gas sample from the exhaust system of an engine for analysis by an exhaust emission analyzer, the apparatus comprising:
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an exhaust gas sampling line having first and second ends, said first end being fluidly connected to the exhaust system of the engine; an exhaust gas sampling line orifice fitted to said exhaust gas sampling line, said exhaust gas sampling line orifice having an inlet; a source of substantially pollutant-free diluent gas; a diluent line having first and second ends, said first end being connected to said source of substantially pollutant-free diluent gas; a diluent line orifice fitted to said diluent line, said diluent line orifice having an inlet, and said exhaust gas sampling line orifice and said diluent line orifice being configured so as to produce equal pressure drops thereacross; a diluent pressure regulator fitted to said diluent line and connected to said exhaust gas sampling line for controlling pressure such that pressure at said diluent line orifice inlet is equal to pressure at said exhaust gas sampling line orifice inlet; a diluted gas outlet line having first and second ends, said first end being connected to the exhaust emission analyzer; a fluid junction, said second ends of said exhaust gas sampling line, said diluent line, and said diluted gas outlet line being connected to said fluid junction; and means for drawing diluted gas through said diluted gas outlet line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for preparing a sample of exhaust gas from the exhaust system of an engine for analysis by an exhaust emission analyzer, said method including the steps of:
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extracting an exhaust gas sample from the exhaust system of an engine and passing said exhaust gas sample through an inlet of an exhaust gas sampling line orifice fitted to an exhaust gas sampling line; extracting a diluent gas from a diluent gas source and passing said diluent gas through an inlet of a diluent line orifice fitted to a diluent line having a pressure regulator; maintaining the volumetric ratio of said exhaust gas sample and said diluent gas at a substantially constant rate with said pressure regulator by controlling pressure such that pressure at said diluent line orifice inlet is equal to pressure at said exhaust gas sampling line orifice inlet; introducing said diluent gas into said exhaust gas sample to create a diluted exhaust gas sample; and directing said diluted exhaust gas sample to the exhaust emission analyzer. - View Dependent Claims (13, 14, 15, 16)
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17. An apparatus for controlling the dilution of an exhaust gas sample from the exhaust system of an engine for analysis by an exhaust emission analyzer, the apparatus comprising:
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an exhaust gas sampling line having first and second ends, said first end being fluidly connected to the exhaust system of the engine; an exhaust gas sampling line flow control valve fitted to said exhaust gas sampling line, said exhaust gas sampling line flow control valve having an inlet; a source of substantially pollutant-free diluent gas; a diluent line having first and second ends, said first end being connected to said source of substantially pollutant-free diluent gas; a diluent line flow control valve fitted to said diluent line, said diluent line flow control valve having an inlet and said exhaust gas sampling line flow control valve and said diluent line flow control valve being configured so as to produce equal pressure drops thereacross; a diluent pressure regulator fitted to said diluent line and connected to said exhaust gas sampling line for controlling pressure such that pressure at the diluent line flow control valve inlet is equal to pressure at the exhaust gas flow control valve inlet; a diluted gas outlet line having first and second ends, said first end being connected to the exhaust emission analyzer; a fluid junction, said second ends of said exhaust gas sampling line, said diluent line, and said diluted gas outlet line being connected to said fluid junction; and means for drawing diluted gas through said exhaust gas sampling line, said diluent line, and said diluted gas outlet line. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. An apparatus for controlling the dilution of an exhaust gas sample from the exhaust system of an engine for analysis by an exhaust emission analyzer, comprising:
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an exhaust gas sampling line having first and second ends, said first end being fluidly connected to the exhaust system of the engine; an exhaust gas sampling line orifice fitted to said second end of said exhaust gas sampling line, said exhaust gas sampling line orifice having an inlet and an outlet; a source of substantially pollutant-free gas; a diluent line having first and second ends, said first end being connected to said source of substantially pollutant-free diluent gas; a diluent line orifice fitted to said second end of said diluent line, said diluent line orifice having an inlet and an outlet and said diluent line orifice and said exhaust gas sampling line orifice being configured so as to produce equal pressure drops thereacross; a diluent pressure regulator fitted to said diluent line and connected to said exhaust gas sampling line orifice inlet for controlling pressure such that pressure at said diluent line orifice inlet is equal to pressure at said exhaust gas sampling line inlet; a bulkstream line having first and second ends, said first end being fluidly connected to said outlet of said exhaust gas sampling line orifice; a diluent connecting line having first and second ends, said first end being fluidly connected to said outlet of said diluent line orifice; a fluid junction connected to said second end of said diluent connecting line and said second end of said bulkstream line, such that the exhaust gas sample is diluted at a constant ratio with said substantially pollutant-free diluent gas to produce a diluted exhaust gas sample; a diluted gas sampling line having first and second ends, said first end being fluidly connected to said fluid junction and said second end being fluidly connected to the exhaust emission analyzer; and means for drawing said diluted exhaust gas sample through said exhaust gas sampling line.
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Specification