Heavy Duty Dynamometer Test Chamber (HDDTC)

In the UK, Millbrook offers two facilities ideally suited for a variety of vehicle and emissions tests on light and heavy duty vehicles - a Variable Temperature Emissions Chamber (VTEC) and a Heavy Duty Dynamometer Test Chamber (HDDTC).

HDDTC Specification

  • 19m x 9m x 5m
  • Speed tracking fan
  • External ambient air circulation
  • Background noise level: 40dB linear
  • Lower cutoff frequency: 70Hz

Chassis Dynamometer

  • Tractive effort of 36,000N
  • Double axle fixed separation (1,350mm)
  • Inertia simulation from 454kg to 40,000kg in 1kg increments
  • Variable speed vehicle cooling fan


  • Fuel economy comparison
  • Cycle development
  • Power testing
  • Constant high power testing – fuels work
  • NVH testing
  • Type IIA endurance brake tests on M3, N3 and ADR (N2 and N3) vehicles in accordance with ECE R13
  • Vehicle cooling trials (uncontrolled ambient temperature)

The table below offers a detailed comparison of the two chambers and their applications. 

  VTEC (Variable Temperature Emissions Chamber) HDDTC (Heavy Duty Dynamometer Test Chamber)
Type 2WD single axle Double axle fixed separation (1,350mm)
Fully Transient Yes Yes
Inertia Range 454-20,000kg 454-40,000kg
Max Speed 200km/h 130km/h
Max Power 200kW above 118km/h  
Max Torque 6,110N 36,000N
Roller Diameter 48" 48"
Cooling Fan Twin large speed tracking fans Variable speed vehicle cooling fan
Drive Cycle Simulation Yes Yes
Temperature Range Controlled -30°C to +50°C No control. External ambient air circulation
Temperatue Control +/-2°C Limitations below -20°C with high heat load No control
Bag CVS Yes (HC, CO, NOx, CO2) No
Raw Gas Sample 2 Streams (HC, CO, NOx, NO, NO2 CO2) 1 Stream (HC, CO, NOx, CO2) - concentration only
Particle Mass Yes 3 phase No
Particle Number Yes - Regulated and ELPI No
Fuel Consumption Regulatory Carbon Balance High-accuracy and fast-response fuel measurement equipment
Other emissions FTIR - NO, NO2, N2O, Ammonia, Formaldehyde None
Size (L x W x H) 26m x 6m x 5m 19m x 9m x 5m
Background Noise Level N/A 40db linear
Lower Cutoff Frequency N/A 70Hz
Approval Testing Yes - TfL, LEB, LUB, CVRAZ No
Climatic Testing Yes No
Shake Down Testing Yes No
Fuel Economy Comparison Yes Yes
Emissions Development Yes Limited
Cycle Development Yes Yes
Power Testing Limited Yes
Constant High Power Testing - Fuels Work No Yes
NVH Testing No Yes
Brake Tests No Type IIA endurance brake tests on M3, N3 and ADR (N2 and N3) vehicles in accordance with ECE R13
Vehicle Cooling Trials Limited on Power Yes at uncontrolled ambient temperature

Sign Up to Millbrook's Free Updates

Passionate about Safety, Customer Service and Technical Excellence