Abstract: An emissions test system includes an emissions analyzer, a contamination index module, and a diagnostic module. The emissions analyzer is configured to determine a concentration of an emission in a sample of exhaust gas from an engine. The contamination index module is configured to determine a contamination index based on at least two of a flow rate of the exhaust gas sample, the concentration of the emission in the exhaust gas sample, an operating duration of the emissions test system, a pressure of the exhaust gas, and a temperature of the exhaust gas. The diagnostic module is configured to identify potential contamination of at least one of the emissions test system and a component in the emissions test system based on the contamination index.

Abstract: An emissions test system includes a dilution tunnel, a clean circuit, a dirty circuit, and a sampling control module. The dilution tunnel is configured to receive exhaust gas from an engine and dilution gas from a dilution gas source. The clean circuit is configured to receive gas from the dilution tunnel. The dirty circuit is configured to receive gas from the dilution tunnel independent of the clean circuit. The sampling control module is configured to direct gas from the dilution tunnel to the dirty circuit when the engine is off at the start of a first test phase. The sampling control module is configured to direct gas from the dilution tunnel to the clean circuit at the end of the first test phase when the engine is switched on during the first test phase.

Abstract: An exhaust sampling system includes a dilution tunnel in which exhaust gas from an engine is diluted with a diluent gas, a sample probe in fluid communication with the dilution tunnel, a sample collector, a first flow path in fluid communication with the sample probe and the sample collector, a source of fill gas, a second flow path in fluid communication with the source of fill gas and the sample collector, and a controller that selectively supplies the diluted exhaust gas to the sample collector through the first flow path during a test phase, and that selectively supplies the fill gas to the sample collector through the second flow path during the test phase. At least a portion of the second flow path is different than the first flow path.

Abstract: A system according to the present disclosure includes a pressure sensor and an engine state module. The pressure sensor is configured to measure pressure in an exhaust gas supply line that supplies exhaust gas from an engine to an emissions measurement system. The emissions measurement system includes a dilution tunnel, a sample probe, and a sample collector. The exhaust gas is diluted with a dilution gas in the dilution tunnel, and the sample probe supplies a portion of the diluted exhaust gas to the sample collector. The engine state module is configured to determine whether the engine is on or off based on at least one of (i) a frequency of pulsations in the exhaust gas supply line pressure and (ii) a magnitude of the pulsations in the exhaust gas supply line pressure.

Abstract: An emissions test system includes a dilution tunnel, a clean circuit, a dirty circuit, and a sampling control module. The dilution tunnel is configured to receive exhaust gas from an engine and dilution gas from a dilution gas source. The clean circuit is configured to receive gas from the dilution tunnel. The dirty circuit is configured to receive gas from the dilution tunnel independent of the clean circuit. The sampling control module is configured to direct gas from the dilution tunnel to the dirty circuit when the engine is off at the start of a first test phase. The sampling control module is configured to direct gas from the dilution tunnel to the clean circuit at the end of the first test phase when the engine is switched on during the first test phase.

Abstract: An emissions test system includes an emissions analyzer, a contamination index module, and a diagnostic module. The emissions analyzer is configured to determine a concentration of an emission in a sample of exhaust gas from an engine. The contamination index module is configured to determine a contamination index based on at least two of a flow rate of the exhaust gas sample, the concentration of the emission in the exhaust gas sample, an operating duration of the emissions test system, a pressure of the exhaust gas, and a temperature of the exhaust gas. The diagnostic module is configured to identify potential contamination of at least one of the emissions test system and a component in the emissions test system based on the contamination index.

Abstract: An exhaust sampling system includes a dilution tunnel in which exhaust gas from an engine is diluted with a diluent gas, a sample probe in fluid communication with the dilution tunnel, a sample collector, a first flow path in fluid communication with the sample probe and the sample collector, a source of fill gas, a second flow path in fluid communication with the source of fill gas and the sample collector, and a controller that selectively supplies the diluted exhaust gas to the sample collector through the first flow path during a test phase, and that selectively supplies the fill gas to the sample collector through the second flow path during the test phase. At least a portion of the second flow path is different than the first flow path.

Abstract: An exhaust sampling system for an engine is provided. The exhaust sampling system may include a source of exhaust gas, an exhaust collection unit including at least one collection bag that selectively receives the exhaust gas, and a sample probe in fluid communication with the source of exhaust gas that selectively supplies the at least one collection bag with the exhaust gas. The exhaust sampling system may also include a controller that permits flow of the exhaust gas from the sample probe to the at least one collection bag in a first state and prevents flow of the exhaust gas from the sample probe to the at least one collection bag in a second state. The controller may determine an extraction rate of the sample probe based on an ON time of the engine during a test phase.

Abstract: A system according to the present disclosure includes a pressure sensor and an engine state module. The pressure sensor is configured to measure pressure in an exhaust gas supply line that supplies exhaust gas from an engine to an emissions measurement system. The emissions measurement system includes a dilution tunnel, a sample probe, and a sample collector. The exhaust gas is diluted with a dilution gas in the dilution tunnel, and the sample probe supplies a portion of the diluted exhaust gas to the sample collector. The engine state module is configured to determine whether the engine is on or off based on at least one of (i) a frequency of pulsations in the exhaust gas supply line pressure and (ii) a magnitude of the pulsations in the exhaust gas supply line pressure.

Abstract: An engine emissions test system according to the principles of the present disclosure includes a sampling conduit, at least one sample bag, a read circuit, and a fill circuit. The sampling conduit is configured to receive exhaust from an engine. The at least one sample bag is configured to store a sample of exhaust. The read circuit is configured to communicate the stored sample of exhaust between the at least one sample bag and an analyzer. The fill circuit includes a fill gas line configured to provide a fill gas to be mixed with the sample of exhaust. The fill gas line extends between a fill gas source and the read circuit.

Abstract: An exhaust sampling system for an engine is provided. The exhaust sampling system may include a source of exhaust gas, an exhaust collection unit including at least one collection bag that selectively receives the exhaust gas, and a sample probe in fluid communication with the source of exhaust gas that selectively supplies the at least one collection bag with the exhaust gas. The exhaust sampling system may also include a controller that permits flow of the exhaust gas from the sample probe to the at least one collection bag in a first state and prevents flow of the exhaust gas from the sample probe to the at least one collection bag in a second state. The controller may determine an extraction rate of the sample probe based on an ON time of the engine during a test phase.

Abstract: An exhaust sampling system for an engine is provided. The exhaust sampling system may include a source of exhaust gas, an exhaust collection unit including at least one collection bag that selectively receives the exhaust gas, and a first sample probe in fluid communication with the source of exhaust gas that selectively supplies the at least one collection bag with the exhaust gas at an extraction rate. The exhaust sampling system may also include a controller that permits flow of the exhaust gas from the first sample probe to the at least one collection bag in a first state and prevents flow of the exhaust gas from the first sample probe to the at least one collection bag in a second state. The controller may control the extraction rate of the first sample probe based on a time during a test phase at which the engine is switched to an ON state.

Abstract: Disclosed is an exhaust sampling system including a plurality of exhaust sampling system zones. The zones are, at least, a sampling conduit, a fill circuit, and a read circuit. A controller is programmed to predict a minimum dilution ratio to avoid condensation in one of the exhaust sampling system zones. The controller is further programmed to run a test procedure in which a sample of exhaust is diluted with a make-up gas at a selected minimum dilution ratio that is greater than or equal to the predicted minimum dilution ratio. Further disclosed are methods of predicting whether condensation occurs during a test procedure.

Abstract: An engine emissions test system according to the principles of the present disclosure includes a sampling conduit, at least one sample bag, a read circuit, and a fill circuit. The sampling conduit is configured to receive exhaust from an engine. The at least one sample bag is configured to store a sample of exhaust. The read circuit is configured to communicate the stored sample of exhaust between the at least one sample bag and an analyzer. The fill circuit includes a fill gas line configured to provide a fill gas to be mixed with the sample of exhaust. The fill gas line extends between a fill gas source and the read circuit.

Abstract: An exhaust sampling system for an engine is provided. The exhaust sampling system may include a source of exhaust gas, an exhaust collection unit including at least one collection bag that selectively receives the exhaust gas, and a first sample probe in fluid communication with the source of exhaust gas that selectively supplies the at least one collection bag with the exhaust gas. The exhaust sampling system may also include a controller that permits flow of the exhaust gas from the first sample probe to the at least one collection bag in a first state and prevents flow of the exhaust gas from the first sample probe to the at least one collection bag in a second state. The controller may determine an extraction rate of the first sample probe based on an ON time of the engine during a sampling period.