Electro-pneumatic module for enhanced gas titration/dilution processing

A NOx detection instrument comprising:

• a gas mixing device comprising:
• an electronically actuated 3/2 way gas valve having a diaphragm, a first inlet port, a second inlet port, and an exit port;
• a conduit in fluid communication with the exit port at a first end of the conduit;
• a mixing chamber in fluid communication with a second end of the conduit;
• and
• a controller configured to control a position of the diaphragm within the electronically actuated 3/2 way gas valve;
• an ozone gas source in fluid communication with the second inlet port of the 3/2 way gas valve;
• and
• an NO2 sensor in fluid communication with the mixing chamber.

A method of measuring a concentration of NOx in a sample gas, the method comprising:

• controlling, by a controller, a diaphragm within an electrically actuated 3/2 way gas valve to assume a first configuration;
• controlling, by the controller, the diaphragm within the electrically actuated 3/2 way gas valve to assume a second configuration;
• causing, by the controller, the diaphragm to alternately assume the first configuration and the second configuration within the electrically actuated 3/2 way gas valve;
• directing a bolus of a sample gas to flow from a first input port of the 3/2 way gas valve into a conduit in fluid communication with an exit port of the 3/2 way gas valve when the diaphragm assumes the first configuration;
• directing a bolus of ozone to flow from a second input port of the 3/2 way gas valve into the conduit when the diaphragm assumes the second configuration;
• directing the bolus of sample gas in the conduit and the bolus of ozone in the conduit to enter a mixing chamber;
• mixing, within the mixing chamber, the ozone and sample gas to form a gas mixture;
• and
• measuring, by a NO2 detector, a concentration of NO2 in the gas mixture.