Caterpillar Inc.

Jerry Kirk Randall

Russell R Graze, Jr

Linda M Riedlinger

Testing of engine particulate matter production during a transient is made more accurate by selecting an appropriate sized opening for a test probe of the sampling system located in the exhaust line upstream from a particulate trap. By examining the pressure signature at the test probe location and utilizing that information in conjunction with a desired volumetric flow rate into the sampling system, a flow opening size for the test probe can be selected that reduces potential oversampling which may be otherwise induced due to the back pressure increases in the exhaust line caused by the presence of the particulate trap. The flow opening into the test probe of the sampling system behaves relative unrestricted when pressure differentials at the test probe location are relatively low, such as during steady state operating conditions, but restricts flow into the sampling system when pressure differentials are relatively high, such as at a pressure during a transient event.

Particulate sampling system and method of reducing oversampling during transients

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.

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East Peoria, IL, United States of America

Jerry Kirk Randall