Introduction to the DMS500

Since 2002 hundreds of DMS500s have been adopted in over 30 countries worldwide for engine research, development and calibration. A unique combination of measurement capabilities; particle size, particle number (PN) and soot mass (PM) all in real time has made the DMS500 the measurement instrument of choice for OEMs, Tier 1s and Universities engaged in engine research and development.

With comprehensive test cell integration and raw sampling capability, the DMS500 is ideally suited to both rolling road and engine test cell applications, while the fast response time allows users to address issues associated with Real Driving Emissions (RDE).

Hundreds of technical publications including SAE papers have used DMS500s for engine research.

Catalytic Stripper and Selectable Roll Off

The addition of a catalytic stripper accessory and software selectable roll offs (for example future 10nm or the existing 23nm), combined with measurement of the full size spectrum between either 5-1000nm or even 5-2500nm, ensures that the DMS500 offers users the required flexibility for PN measurement as engines and legislation evolve.

Measurement Metrics

Particle emissions are subject to a variety of metrics, including particle mass and particle number.

Particle Mass

Real-time engine out mass measurement using DMS500

Particle mass is normally measured for legislative purposes using filter paper measurements. This technique has required continuing improvement in sensitivity of mass measurement devices, since the change in mass of the filter paper becomes progressively smaller as engine calibrations improve.

Filter paper mass is inherently an offline technique- requiring collection of soot over a period of time before the final weight can be taken. Since engines are tested on transient drive cycles, such an integrated measurement gives no information about what points in the drive cycle contribute most to the cycle soot emissions. An online mass measurement technique is needed to support this. Instruments such as the AVL Micro Soot Sensor allow direct mass measurment, but have a T90-10% response time of around 1 second. Since transients on engine test cycles are typically sub-second, and AFR excursions in both Diesel and gasoline engines are typically associated with high particle mass emissions, an instrument with significantly sub second T10-90% response time is desirable. The DMS500 offers a T10-90% response time of just 200ms.

The DMS500's sampling system allows measurement both pre- and post-aftertreatment. For example, sampling upstream of a GPF or DPF, the DMS500 can calculate the soot mass output from the engine presented to the filter. This mass data can be used to reduce engine out soot mass, and to predict the GPF/DPF soot load. Sampling downstream of the GPF/DPF, the DMS500 can give real-time tailpipe particle mass, showing the combined effect of engine out emissions and after-treatment performance on tailpipe emissions, including transient effects such as soot cake cracking.

Particle Number

Comparison of DMS500 and PMP/CPC particle number data

Euro 6 legislation imposes a restriction on the number of solid particles a vehicle can emit, either as N/km for light duty or N/kwh for heavy duty.

The particle counting technique is specified in the legislation. This legislated technique offers excellent sensitivity and commercially available instruments include the Horiba MEXA 1000 SPCS and the AVL 489 APC.

However, the T10-90% response time of Euro 6 PN 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.

The DMS500 system is a non-certification system which uses a different technique to measure particle concentration. The DMS500 offers a T10-90% response time of 200ms,offering insights into transient calibration issues which contribute a significant proportion of the total emissions on cycle simply unavailable from legislative measurement devices.

The DMS500 has been adopted by vehicle manufacturers and engine developers worldwide as a key tool to understand and reduce PN emissions, from Diesel, GDI and other fuels.

Particle Size

Video showing DMS500 size measurements from GDI engine during drivecycle

As particle filters are adopted for both GDI and Diesel engines, particle size becomes increasingly important. Although the two metrics for particle emissions (mass and number) do not require particle size measurement, the efficiency of filtration of a GPF or a DPF is heavily size dependent. To understand the filtration performance of a GPF or DPF, measurement of the size distribution of the exhaust is required. Assuming a nominal size distribution will lead to errors- for example engine load and EGR both affect the particle size distribution. Although some instruments measure one parameter (e.g. PM) and offer a surrogate output of PN, changing particle size will change the factor between these two quantities, making such assumptions inherently inaccurate.

DMS500 Features

DMS500 sampling from vehicle
  • Measurement of the particle size / number spectrum from 5nm to 2.5μm
  • Measurement of Particle Number (PN) for Euro 6 development and beyond
  • Measurement of Particle Mass (PM)
  • The fastest time response available: 10 Hz data, 200ms T10-90% response
  • Raw sampling, pre- or post DPF / GPF
  • Test cell integration via AK protocol
  • Cold-cell testing
  • High altitude testing (up to 13,000ft / 4,200m)
  • Measurement of particle emissions from other sources- e.g. blowby, braking...

Fastest Time Response

The fast T10-90% time response is especially useful for investigation of fast changing concentrations and particle sizes. This is particularly important with Gasoline Direct Injection, where high particulate number emissions tend to be associated with transient conditions, rather than steady state. As test cycles become increasingly transient (e.g. World Harmonized Test Cycle & Non Road Transient Cycle) the advantage of fast time response becomes more widespread.

Even during steady state conditions, the DMS500 dramatically increases the efficiency and convenience of experimental measurements, requiring less time at steady state conditions to make the measurement. Indeed, since engine parameters are changing during steady state conditions (e.g. stabilisation in piston temperatures) a question arises about how long to allow stabilisation at steady state conditions before measurement. The DMS500 identifies changing emissions in real time.

Control and Test Cell Integration

Screenshot of DMS user interface software

The DMS500 is controlled by a PC located up to 200m away via an Ethernet interface. Data is recorded to the PC hard disk.

A comprehensive AK protocol command set allows allows full control, monitoring and datalogging from the test bench.

Data presentation tools for MS Excel are included to assist in visualising the data from the DMS500.

Raw Sampling System

Heavy Duty Diesel spectrum on FTP Transient Cycle

The DMS500 is available as standard with a heated sampling line (191C operation) and two stages of integrated dilution. This enables direct measurement from the engine exhaust with no additional equipment required.

Traceable Calibration

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

More Information

Download a brochure with specifications. 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 dms01.pdf 890.73 KB 13-Nov-2017
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
Water pipe smoking Application note PDF icon dms22 Water pipe smoking.pdf 931.87 KB 04-Aug-2017