Vauxhall's 1.7-litre Astra Ecoflex generates 130PS - 5PS more than the existing Astra 1.7 CDTi engine - but returns CO2 emissions which are 20g/km lower: just 99g/km.

A key part of the improved emissions performance is an all-new engine management system, allowing a reduced compression ratio, and a new fuel injection system with eight injections per cycle at 1800 bar. A new variable geometry turbocharger also provides greater boost-pressure control.

Low friction piston rings, tappets and gudgeon pins improve efficiency, while pressure sensor glow plugs enable more accurate combustion control. Warm-up is quicker thanks to an oil-cooler bypass system.

The Ecoflex is fitted with a friction-reduced six-speed gearbox with new ratios chosen to match the revised engine. Economical driving is aided by a instrument panel graphics and a gearshift indicator.

A kinetic energy recovery system harvests energy on the overrun or during braking to recharge the main electric battery, allowing the alternator to shut down when there is sufficient charge to run ancillaries. In addition, a clutch activates the air conditioning compressor only when it's needed. LED daytime running lights reduce energy consumption compared to conventional lamps.

The Astra Ecoflex runs on low rolling resistance tyres and air resistance is minimised by a 12mm reduction in ride height and the addition of a radiator grille shutter, which automatically closes at high speeds.

The 1.7-litre Ecoflex shares the start/stop system already in use on the 1.3-litre and 2.0-litre models, which stops the engine when the car is idling in neutral and restarts it as soon as first gear is engaged. A high-performance battery is fitted to cope with the demands of restarting the diesel engine. The system can be deactivated via a centre-console-mounted 'eco' switch.

How drivetrain tech helps the Astra Ecoflex 1.7 achieve 99gCO2/km


  1. Start/stop system reduces idling time to improve fuel economy
  2. Low temperature exhaust gas recirculation reduces NOx emissions
  3. Oil cooler by-pass reduces warm-up time
  4. Switchable water pump reduces friction and warm-up time
  5. Diamond-like coating on tappets and gudgeon pins reduces friction
  6. Close coupled oxidation catalyst
  7. Pressure sensor glowplugs improve combustion control
  8. Friction reduced piston rings