Testing Equipment

The SEMTECH-DS unit includes a set of gas analyzers, an engine diagnostic scanner, a GPS, an EFM, and embedded software. The gas analyzers measure the concentrations of NOx (NO and NO₂), HC, CO, CO₂, and oxygen (O₂) in the vehicle exhaust. The SEMTECH-DS uses the Garmin International, Inc. GPS receiver model GPS 16 HVS to track the route, elevation, and ground speed of the vehicle on a second-by-second basis.

TTI’s SEMTECH-DS uses the SEMTECH EFM to measure the vehicle exhaust flow. Its post-processor application software uses this exhaust mass flow information to calculate exhaust mass emissions for all measured exhaust gases. The photos to the right show the TTI’s SEMTECH-DS, as well as the EFM installed on a HDDV in a previous test conducted by TTI researchers.

The CATI Axion OEM-2100 is a PEMS unit used by TTI to measure PM mass during on road testing. The Axion system is comprised of a gas analyzer, a PM measurement system, an engine diagnostic scanner, a GPS, and an on-board computer. The PM measurement capability includes a laser light scattering detector and a sample conditioning system. The PM concentrations were converted to mass PM emissions using concentration rates produced by the Axion system and the exhaust flow rates collected by the EFM.

The DMM 230-A is a real time PM measuring instrument for vehicular emissions testing. The DMM can be used for both gasoline and diesel engines. The DMM provides second-by-second analysis of the PM concentrations from the vehicle exhaust, providing both total PM mass measurements and particle mass size distribution of the particles up to 1.5μm in 6 size bins. The DMM is used in conjunction with the microdilution system to measure the diluted exhaust directly from a test vehicle.

TTI uses its microdilution sampling system (MSS) to sample PM filters and MSAT cartridges. The exhaust will be transferred through a heated line to the MSS from a probe in the outlet of the SEMTECH EFM. The MSS uses two Dekati diluters and a Dekati air heater to dilute the raw sample from the vehicle exhaust. The MSS is also connected to the DMM to measure real time PM mass of the diluted sample.

A Model 42i gas analyzer and Model 48i manufactured by Thermo Scientific Inc. is used for measuring NOx and CO concentrations. The 42i analyzer measures NOx concentrations for chamber and real-world testing, which will be used for monitoring NOx concentration changes during testing. The analyzer measures both NO and NO₂ independently by using chemiluminescence technology, and provides outputs for NO, NO₂, and NOx. The concentrations are recorded and reported in units of ppb or mg/m³ at intervals of 40-to-300 seconds. The lowest detectable limit at a 60-second averaging time is 0.40 parts per billion (ppb) while the highest is 100 ppm or 150 mg/m³. The 48i analyzer measures CO concentrations for chamber and real-world testing. The 48i analyzer can measure concentrations up to 10,000 ppm.

A Model 600MHFID gas analyzer (600MHFID) manufactured by California Analytical Instruments, Inc. will be used for measuring THC concentrations although it has capability of measuring methane (CH₄), non-methane hydrocarbon (NMHC), and THC. The analyzer will measure THC concentrations for chamber and real-world testing, which will be used for monitoring THC concentration changes during the testing. The analyzer measures THC by using flame ionization detection principle and provides outputs for CH₄ only, NMHC, and THC. The concentrations are recorded and reported in units of ppm at intervals of less than 2 seconds. The lowest detectable limit is 10 parts per billion (ppb) while the highest is 10,000 ppm.

TTI is the home of the Environmental and Emissions Research Facility (EERF), which is located at the Riverside Campus of Texas A&M University. The EERF includes an environmentally controlled test chamber with dimensions of 75′ long x 23′ wide x 22′ high. The chamber, the largest of its kind in the nation, is capable of holding a tractor trailer combination. The chamber has both temperature and humidity controls, as well as a solar array and a wind simulator. The chamber can provide temperatures from -25°C to 55°C. The humidity is capable of reaching 70%RH at 40°C with the solar lights running. The solar lights cover an area 8’6″ x 10′, and can raise and lower with the chamber. The wind simulation is capable of producing wind speeds of up to 35 MPH across the entire front section of a HDDV truck, from a height of 6″ up to 10′. The environmental chamber at the EERF allows TTI to conduct cold start testing under extreme conditions without having to leave their facilities and wait for the appropriate conditions. The picture to the right shows the chamber with no vehicle inside.