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.

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

Comparison of DMS500 and PMP/CPC particle number data

The DMS500 system is a non-certification system which uses a different technique 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.

The DMS500 has been adopted by vehicle manufacturers and engine developers worldwide as a key tool to understand and reduce particle emissions, particularly from GDI engines.

DMS500 Features

DMS500 sampling from vehicle
  • Measurement of the engine exhaust particle size / number spectrum from 5nm to 2.5μm
  • Measurement of particle emissions from other sources- e.g. blowby, braking...
  • The fastest time response available: 10 Hz data, 200ms T10-90% response
  • Mass measurement and automatic aerosol mode discrimination for solid particle number counting (for Euro 6 development)
  • Enhanced Sensitivity- DMS500 MkII now 3x more sensitive than DMS500 MkI
  • Test cell integration via AK protocol - suitable for auto mapping projects
  • Capable of cold-cell testing
  • Capable of high-altitude testing

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

Screenshot of DMS user interface software

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

Heavy Duty Diesel spectrum on FTP Transient Cycle

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.

Traceable Calibration

Each DMS500 undergoes an empirical calibration procedure, involving real aerosols, taking full account of particle losses, and even different particle morphologies thus preventing the drop in accuracy at larger sizes seen in some other analyzers. Calibration certificates for spherical and agglomerate calibrations are provided.

An optional portable size check kit allows the user to check the sizing accuracy of the DMS500 on site, without the need for any other equipment.

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.

Key Application Notes 
Title Data type Download File Size Last updated
Number : Size Spectrum Correlation with Particulate Mass Measurements Application note PDF icon dms01v05.pdf 194.03 KB 24-Feb-2015
Measurement of Volatile Aerosols with the dms500 Application note PDF icon dms02v01.pdf 45.93 KB 24-Feb-2015
DMS500 sampling options Application note PDF icon dms03v04.pdf 511.06 KB 24-Feb-2015
DMS500 measurement of drug delivery inhalers Application note PDF icon dms04v02.pdf 85.64 KB 24-Feb-2015
Measurement of DPF/CRT performance with DMS500 Application note PDF icon dms05v02.pdf 1.2 MB 24-Feb-2015
Real-time mode finding and lognormal fitting with DMS series fast particulate spectrometers Application note PDF icon dms06v03.pdf 682.83 KB 24-Feb-2015
Flame Sampling with DMS500 Application note PDF icon dms07v01.pdf 260.74 KB 24-Feb-2015
Gasoline Direct Injection Particulate Measurement with the DMS Series Application note PDF icon dms08v01.pdf 919.53 KB 24-Feb-2015
Particle number measurement with the DMS Series Application note PDF icon dms09v01.pdf 351.19 KB 24-Feb-2015
Ambient aerosol sampling with DMS500 Application note PDF icon dms10v01.pdf 295.83 KB 24-Feb-2015
DMS500 Installation Guide for Engine Sampling Application note PDF icon dms11v02.pdf 512.72 KB 02-Feb-2015
Real-time aerosol size, number and mass measurements from an electronic cigarette Application note PDF icon dms12v01.pdf 120.11 KB 24-Apr-2014
Real-time particle size measurements of user triggered electronic cigarette smoke Application note PDF icon dms14v02.pdf 910.84 KB 16-Aug-2016
Real-time particle size measurements of heat-not-burn tobacco device Application note PDF icon dms15v01.pdf 870.75 KB 09-Oct-2014
Brake particle measurements Application note PDF icon dms17v01.pdf 529.01 KB 08-Mar-2016
Nanoparticle emissions from cooking Application note PDF icon dms19v01 Nanoparticle emissions from cooking.pdf 1.94 MB 10-Oct-2016