MDLT-ONE - Micro Dilution Tunnel

Micro Dilution Tunnel

The MDLT-ONE is designed to sample particulate emissions using the partial flow dilution method. A small portion of the total exhaust is diluted with HEPA* filtered air to create a constant flow rate through particulate filters to collect Particulate Matter (PM). Compliant to the latest regulations, the new MDLT-ONE is very compact and offers faster response by the use of high precision venturi flow meters and a piezo actuated valve.

*HEPA: High Efficiency Particulate Air

Segment: Automotive
Manufacturing Company: HORIBA, Ltd.

Small footprint

Heated filter system and flow controllers installed in a single rack. Swivel connection of tunnel section to cabinet allows flexible installation.

Flow weighting (EPA-approved technology)

Allows user to collect PM on a single filter over all three phases of FTP by adjusting sampling flow rate over the filter to weight the filter face velocity over the three phase of the FTP based on weighting targets. This EPA-approved technology increases the measurement accuracy for meeting the upcoming CARB LEV III 1`mg/mile emission limit and reduces filter weighing cycles from three to one, eliminating manual checks and calculations.

Automatic filter changer

Increases testing efficiency, allowing a maximum of 28 tests to be run without manual intervention. This feature can be mounted in the main rack to keep equipment footprint small.

Automatic calibration software enhances accuracy and ease of use

The MDLT-ONE series performs automatic calibration by flowing air in-series through two venturi flow meters and correcting any difference to zero in the software. This can be included in an automated sequence within a test template.

Integrated Operating Platform

HORIBA ONE series systems employ a common use interface, “HORIBA ONE PLATFORM” offering future expandability and ease of integration into test automation systems.


PM Emission Measurement of All Engines

R&D Support of Engine and After Treatment System

Complies with worldwide emissions regulations


EU: Euro VI (HDV)

US: 40 CFR Part 1065/1066

Japan: Post new long term

EU: Stage IV / V (NRMM)



System outline
PM sampling methodPartial flow dilution method
Control modes for dilutionProportional sampling mode (Const. split ratio)/ Fixed dilution ratio mode (Const. dilution ratio)/ Fixed flow rate mode (Manual control)
Control methods for dilution・Real-time control based on analog input of exhaust flow rate
・Control based on learned pattern of exhaust rate
Required signal for gas samplingIsolated analog signal (0 to 10 V)
Flow rate of diluted gas25 to 80 L/min*1 (under the condition of 20 °C and 101.3 kPa)
Accuracy of dilution ratioWithin ± 5 % (excluding the system with AFIC)
When dilution ratio=15 rate at 20 °C and 101.3 kPa: 53 to 80 L/min
PM mass calculation*2PM mass (in g/test or g/kWh) can be calculated and saved, based on integrated values of flow rated and dilution ratio.
System configuration・Main unit: Dilution-tunnel unit
・Operation unit: PC, monitor, keyboard and mouse (table is not included)
Utilities・Purified air: for dilution gas, 400 to 700 kPa, oil free, at least 100 L/min (at 20 °C and 101.3 kPa)
Power supply voltage and frequency・Main unit: 100/110/120/200/220/230/240 V AC, 50/60 Hz, single phase
・Operation unit: 100/110/120/200/220/230/240 V AC, 50/60 Hz, single phase
Power requirementsMain unit: Max. 3.0 kVA / Operation unit: Max. 0.5 kVA
Dimensions・Main unit: 570 (W) × 730 (D) × 1700 (H) mm
・Space for operation unit: 900 (W) × 500 (D) mm (table is not included)
Mass Main unit: Approx. 300 kg (excluding operation unit)
Number of filter lines Max. 6 lines (5 for sample, 1 for bypass)
Type of filter holder・φ70 mm type: actual PM sampling area φ60 mm, with back-up filter
・φ47 mm type: actual PM sampling area φ38.8 mm*1, with back-up filter*1
Operating conditions
Sampling PressureBetween atmospheric pressure and up to 40 kPa    Back pressure of exhaust line: Less than 1 kPa
Filter auto-changer*3Changer for automatic replacement of PM filter (φ 47 mm), both single-filter method and multi-filter method are available.
Valve switchingAdditional air valve before filter (Replacement of sampling filter on bypass mode)
HOST interface*3LAN communication using a 10 Base T port
Conforms to IEEE802.3 (ISO880 2/3)
Conditioner for dilution air / Compressor


*1, For the filter face velocity in the regulations (less than 100 cm/s), the flow rate for the φ47 mm filter must be 65 standard L/min.
*2, Input the amount of PM collected on filter to calculate PM mass. It is necessary to input engine output (kW) to calculate the PM mass engine output (g/kWh).
*3, Please contact HORIBA, when you order.

Engine testing in automobiles and components
Engine testing in automobiles and components
Particle Measurement in the Sub-23nm Range
Particle Measurement in the Sub-23nm Range
Concerns exist that advances in modern engine technology may contribute to large portions of solid particles at sizes smaller than 23nm. The EU Joint Research Center has confirmed this concern in several investigations.

Request for Information

Do you have any questions or requests? Use this form to contact our specialists. * These fields are mandatory.

Related products


Constant Volume Sampler


Ultrasonic Exhaust Flow Meter


FTIR Exhaust Gas Analyzer Dilute Measurement Type


FTIR Exhaust Gas Analyzer Direct Measurement Type

More MEXA-1170HCLD

Heated Type NOx Analyzer

More MEXA-1170HFID

Heated Type THC Analyzer

More MEXA-1170SX

Motor Exhaust Gas Sulfur Analyzer

More MEXA-1300R

Motor Exhaust Gas Analyzer

More MEXA-2000SPCS series

Solid Particle Counting System

More MEXA-584L

Automotive Emission Analyzer

More MEXA-730λ

Air-to-fuel Ratio Analyzer


Motor Exhaust Gas Analyzer


FTIR Motor Exhaust Gas Analyzer


Laser Spectroscopic Motor Exhaust Gas Analyzer

More OBS-ONE GS Unit

On-board Emissions Measurement System


On-board Emissions Measurement System for NH3/N2O

More OBS-ONE PM unit

On-board Emissions Measurement System

More OBS-ONE PN Unit

On-board Emissions Measurement System

More OBS-ONE SPN10 Unit

On-board Emissions Measurement System for SPN10


Particulate Filter Management System

More PTFM-1000V2

Pitot Tube Flow Meter


Dual Pitot Tube Flow Meter