DMS500 MkII Fast Engine Particulate Analyzer
Introduction to the DMS Series
The DMS500 was launched in 2002, as the first of a new type of instrument. It combines electrical mobility measurements of particles with sensitive electrometer detectors, to give ouputs of particle size, particle count (number concentration) and mass in real time.
Refreshed in 2009 as the MkII with significant upgrades in sensitivity and test cell integration, the DMS500 is ideally suited to laboratory or engine test cell applications.
The DMS50 builds on the DMS500 technology, offering similar features in a smaller package ideally matched to in-vehicle or mobile measurements.
Engine Particulate Measurement
Traditionally engine particulate has been quantified using mass as a metric, derived through filter paper measurements. This technique has increasingly pushed the bounds of available technology, since the change in mass of the filter paper becomes progressively smaller as engine calibrations improve.
The new Euro 6 legislation brings a restriction on the number of solid particles a vehicle may emit, either as N/km for light duty or N/kwh for heavy duty. The particle counting technique is included in the legislation, using a Volatile Particle Remover to eliminate any liquid particles, and then a Condensation Particle Counter to count the solid particles which remain. From accurate flow rate measurement, the volume concentration (N/cc) may be calculated. This technique offers excellent sensitivity (for post DPF or gasoline measurements where concentrations may be comparatively low) and commercially available instruments include the Horiba MEXA 1000 SPCS and the AVL 489 APC.
However, the T10-90% response time of Condensation Particle Counters is typically greater than 1 second. Due to the highly transient nature of particle emissions, particularly from GDI engines, this restricts their use in calibration of the engine / strategy for compliance, although the final certification testing must be performed with such a system.
Fast Response Particle Counting
The DMS500 system is a non-certification system which uses a different techique to measure particle concentration. The system offers a significantly faster time response, and is correspondingly able to give greater insight into transient calibration issues which contribute a significant proportion of the total emissions on cycle.
DMS500 Features
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Measurement of the exhaust particle size / number spectrum from 5nm to 2.5μm
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The fastest time response available: 10 Hz data, 200ms T10-90% response
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Built-in two stage dilution for direct engine exhaust measurements
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Mass measurement and automatic aerosol mode discrimination for solid particle number counting (for Euro 6 development)
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Enhanced Sensitivity- DMS500 MkII now 3x more sensitive than DMS500 MkI
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Test cell integration via AK protocol
The Cambustion DMS500 offers measurement of the particles between 5nm up to 2.5μm.
Fastest Time Response
Special patented features of the DMS500 give it the fastest time response available in any ultrafine aerosol size measurement.
The fast T10-90% time response is especially useful for investigation of fast changing concentrations and particle sizes. This is particularly important for engine development especially with Gasoline Direct Injection, where high particulate number emissions tend to be associated with transient conditions, rather than steady state.
Even during steady state conditions, the DMS500 dramatically increases the efficiency and convenience of experimental measurements compared with scanning instruments.
Control and Test Cell Integration
The DMS500 is controlled by a PC via an Ethernet interface, allowing the PC to be located up to 200 m from the instrument.
The user interface includes datalogging of the spectrum, including real-time aerosol mode information.
The DMS500 is designed to easily integrate with other test equipment- four analogue inputs are recorded to the data file, and four analogue outputs may be configured in software. The instrument can be controlled via AK protocol for seamless test cell integration.
Data presentation tools for MS Excel are included to assist in understanding the data from the DMS500.
Integrated Sample handling & Conditioning
The DMS500 may be ordered with an optional integrated two-stage diluter and heated sample line, allowing direct measurements from engine exhausts with no additional equipment. The dilution system extends instrument cleaning intervals, allowing the DMS500 to join other test cell equipment as standard tools.
The unique combination of the particle size range and the time reponse of the DMS500 allows investigation of previously unmeasurable events. The data on the left show short lived normal combustion, visible smoke, and nucleation mode aerosols, produced during and after a heavy acceleration from a Diesel vehicle.
Mass Measurement and Solid Particle Concentration
The DMS500 automatically discriminates between aerosol modes.
When applied to Diesel or GDI exhaust, this allows the Nucleation (liquid) and Accumulation (solid) modes to be processed separately, enabling PMP (proposed Euro 5/6 particle N/ km) comparable number concentration measurements without the use of a Volatile Particle Remover. For more information, download the application note.
The instrument also calculates real-time particulate mass concentration. For more information download the application note.
All instrument outputs may be compensated in real time for total exhaust mass flow, with a suitable external analog flow signal.
Contact Cambustion for more information and prices.