Heavy-duty engine emissions tests

Ricardo recently commissioned from Emprise a new full-dilution emissions-measurement system at its Chicago Technical Center.

Dilute-phase exhaust emissions testing capability for heavy-duty, off-highway engines up to 600 hp (450 kW) has been added to an existing dynamometer test cell at Ricardo, Inc.'s technical center in Burr Ridge, IL. Previously capable of only raw gas emissions measurement, the system is now suitable for development and certification testing of engines (diesel and gasoline cycles with both liquid and gaseous fuels) according to EPA, CARB, EC (European Commission), and ISO 8178 protocol requirements. Designed and constructed on a turnkey basis by Marietta, GA-based Emprise Corp., the system includes a dilution air-conditioning unit (ACU), heavy-duty diesel emissions analytical system, and test-cell-control and data-acquisition computer.

The general principle of the system's operation is to mix the engine exhaust with a controlled volume of ambient air so that the exhaust gases experience similar cooling and dilution effects to those that would be experienced in service. A secondary tunnel cools and dilutes samples drawn for particulate measurements. To ensure consistent test results, all dilution conditions are carefully controlled to avoid moisture condensation, sample paths are leak-free, and all instruments are calibrated using precise standards. The emissions analytical system consists of five major interrelated parts, including dilution air supply, exhaust dilution tunnel, bag sampling system, gaseous emissions analysis system, and particulate sampling system.