Abstract: A mixing system with proportional dilution gas sampling, and associated proportional dilution gas sampling methods are provided. The mixing system includes a mixing portion, a gaseous inlet, a dilution inlet, and a mixture outlet. A flow meter in flow communication with the dilution inlet has an output indicative of the dilution gas flow rate. A dilution sample line in flow communication with the dilution inlet collects samples of the dilution gas. A dilution sample flow controller along the dilution sample line is applicable to vary the dilution sample flow rate through the dilution sample line. Control logic receives the flow meter output, processes the flow meter output, and operates the dilution sample flow controller to vary the dilution sample flow rate. The dilution sample flow rate is varied in response to variations in the dilution gas flow rate such that the dilution sample flow rate tracks a value which is substantially proportional to the dilution gas flow rate.

Abstract: A computerized method and system are provided for determining air/fuel ratio of an engine's combustion process from its exhaust emissions wherein alternative methods for calculating the amount of water in the exhaust emissions are available according to the measurement situation and/or the preference of the user. The calculation types may include calculation types such as the Brettschneider/Spindt calculation type, the Simons calculation type or the no O2 calculation type. Pop-up menus on a computer monitor are used for selecting the basic calculation type. The algorithm of the present invention preferably uses a fixed point iteration wherein an initial value is assumed for oxygen gas which is then used to calculate water moles and then subsequently the water moles is used to calculate another oxygen value. This is repeated until the new value for oxygen gas is no longer significantly different than the old value for oxygen gas. This happens typically after just a few iterations.

Abstract: A mixing system includes a dilution inlet, an elbow duct, and a gaseous inlet in flow communication with the elbow duct along the elbow duct outer turning radius. The elbow duct has a first end in flow communication with the dilution inlet, and a second end outlet for connecting to external equipment, such as a sampling system.

Abstract: A system is provided in an exhaust emission sampling system for controlling a flow controller in order to compensate for the effects of changing water vapor content in a diluted sample having a predetermined dilution ratio. A water measuring device such as a relative humidity sensor generates a water vapor signal based on the amount of water vapor in the diluted sample. The water vapor signal is then processed within a control unit to obtain a value for the amount of water in the diluted sample. A control signal is generated by the control unit based on the amount of water vapor, flow rate of the exhaust emissions, and also, on the type of fuel used in the combustion process to control the flow controller which is, preferably, a mass flow controller. A second system is provided in an exhaust emission analyzing system for determining a final amount of pollutants also compensated for the effects of changing water vapor content in the exhaust emissions.

Abstract: In a first embodiment of the present invention, a control method and system are provided in an exhaust emission sampling system for controlling a flow controller in order to compensate for the effects of changing water vapor content in a diluted sample having a predetermined dilution ratio. A water measuring device such as a relative humidity sensor generates a water vapor signal based on the amount of water vapor in the diluted sample. The water vapor signal is then processed within a control unit to obtain a value for the amount of water in the diluted sample. A control signal is generated by the control unit based on the amount of water vapor, flow rate of the exhaust emissions, and also, on the type of fuel used in the combustion process to control the flow controller which is, preferably, a mass flow controller.