Abstract: A system to measure a parameter of a particulate laden gas flow may include a conduit enclosed by a boundary wall directing the particulate laden gas flow and a sensor configured to measure the parameter. The system may also include an annular averaging chamber extending radially outwardly from the conduit. The averaging chamber may be positioned such that the sensor is fluidly coupled to the conduit through the averaging chamber. The system may further include a porous element extending around the conduit. The porous element may be positioned such that the averaging chamber is fluidly coupled to the conduit through the porous element.

Abstract: A dilution device includes an inlet port and an outlet port. The dilution device also includes a first porous conduit defining an internal flow passage. The first porous conduit has a plurality of pores that communicate between an outside region external of the first porous conduit and the internal flow passage. The dilution device also includes a second porous conduit disposed around the first porous conduit. The second porous conduit defines a first chamber peripherally about the first porous conduit. The second porous conduit has a plurality of pores that communicate between an outside region external of the second pours conduit and the first chamber. The dilution device further includes a housing disposed around the second porous conduit. The housing defines a second chamber peripherally about the second porous conduit. The housing has an inlet port in communication with the second chamber.

Abstract: A method for controlling the flow through an exhaust sampling system includes sensing an operating characteristic of a power source, extracting a sample of an exhaust flow of the power source, combining the sample with an additional flow of fluid, and measuring a particulate level of the combined flow. A flow rate of the extracted sample is controlled to be substantially proportional to a flow rate of the exhaust flow based on a difference between the combined flow and the additional flow.

Abstract: A particulate sampling system is disclosed. The particulate sampling system may include an exhaust sampling unit and a dilution flow assembly to supply dilution air to the exhaust sampling unit. The particulate sampling system may also include a total flow assembly to receive dilution air and exhaust. The particulate sampling system may further include a flow regulation assembly configured to control flow rates in the dilution flow assembly and the total flow assembly. The particulate sampling system may also include a flow check assembly configured to measure the accuracy of the flow regulation assembly.