Patent ID: 8256307
Filing Date: 2012-09-04
Classification: G01N

Abstract:
1. A method of operating an exhaust sampling system, comprising the steps of: determining an expected pressure rise at a test probe location to occur during a specific transient to be tested; selecting a flow opening with an L/D ratio responsive to the expected pressure rise; flowing exhaust through the flow opening into a test probe positioned in an exhaust stack at the test probe location during an actual testing procedure for the specific transient; unrestricting the flow into the test probe responsive to the L/D ratio when a pressure differential between the exhaust stack at a probe location and atmospheric pressure is small at a beginning of the specific transient during the actual testing procedure, but restricting the flow into the test probe responsive to the L/D ratio when the pressure differential is large due to the expected pressure rise during the specific transient of the actual testing procedure.