4WD Variable Temperature Emissions Chamber

At a glance

Millbrook's new VTEC is a heavy duty climatic emissions chassis dynamometer facility for TfL emissions, CVRAS, real driving emissions simulation, development and product benchmarking testing. It is suitable for diesel, petrol, LPG, CNG, electric and hydrogen vehicles.

Bus emissions test cycle engineers working in the VTEC at Millbrook Proving Ground
Exterior of Millbrook's Variable Temperature Emissions Chamber (VTEC)
Exterior of Millbrook's Variable Temperature Emissions Chamber (VTEC)

In 2020, Millbrook is superseding its iconic Variable Temperature Emissions Chamber (VTEC) at Millbrook Proving Ground in the UK with a brand new vehicle emissions test facility capable of handling even heavier vehicles (up to 60 tonnes of inertia) and 4WD vehicles.

The new VTEC is climatically controlled from -30°C to +50°C and is designed to test trucks, buses and off-highway vehicles for emissions, fuel and lubricant performance and climatic performance.

It is designed to test electric vehicles to determine energy consumption, range and energy efficiency and to test vehicles using alternative fuels such as hydrogen, LNG and CNG for range, emissions and fuel consumption over a drive cycle.

Download VTEC specification


  • 25m x 7m x 6m (L x W x H) with a door size of 4m x 5m (W x H)
  • 4WD chassis dynamometer
  • Roller diameter: 1.83m (72”)
  • Can support 2WD, 4WD or Tri-axle vehicles
  • Wheelbase range: 3.5-8m
  • Inertia range: 3000 to 45,000kg (up to 60,000kg with reducing accel rate)
  • Max rotating speed: 135km/h
  • Max axle load: 20,000kg
  • Continuous power: 450kW front; 587kW rear (from 53 km/h)
  • Continuous torque: 28,421N front; 40,000N rear (to 53 km/h)
  • Overload of 150% (every 10 minutes)
  • Dynamic gradient profile capability
  • Rear axle pull down system to simulate up to 10,000kg
  • Augmented braking capability to replicate lorry trailer brakes
  • Chain restraint system

Speed Tracking Fan

  • 2 mobile speed tracking fans, each with 800mm x 750mm frontal area
  • Air volume of 72,000m3/h
  • Adjustable front height of 410mm

Environmental Performance

  • Climatic control -20°C to +50°C (+/-1.5°C control)
  • Controlled humidity of 5.5 to 20g/kg (14 to 50°C)
  • Full CVS heavy duty spec 160m3 multi venture
  • 4 phase bag analysis system (HC, CO, NOx, NO, NO2, N2O CO2)
  • Raw dual stream gaseous emissions (HC, CO, NOx, NO, NO2, CO2)
  • Exhaust EGR measurement
  • AVL APC for PN measurement
  • Dedicated PM filter weighing chamber
  • Hydrogen fuel consumption by mass measurement method
  • Optional capabilities: MSS, DMS500 particle number/size measurement
  • TfL compliance emissions testing
  • CVRAS accreditation testing / LowCVP HGV accreditation testing
  • RDE simulation in a repeatable and controlled environment
  • On dyno evaluation of VECTO cycles
  • Hydrogen / EV range and energy consumption testing
  • Fuels and lubricant heavy duty application assessment testing
  • Development and product benchmarking testing
  • Climatic testing / urea defrost testing
  • Vehicle / engine performance testing
  • Driveline resistance testing
Dynos in Millbrook's 4WD VTEC facility

Installation of roller dynamometers in June 2020

Bus emissions test engineer working in the VTEC chassis dynamometer at Millbrook Proving Ground

The original VTEC emissions test facility at Millbrook Proving Ground

Building a new VTEC test facility at Millbrook Proving Ground in 2019

Exterior of Millbrook's Variable Temperature Emissions Chamber (VTEC)

The new, 4WD VTEC nearing completion in 2020

Millbrook's 4WD Variable Temperature Emissions Chamber

Completion of the external building work in June 2020