The new Vauxhall Insignia ecoFLEX model has a 2.0-litre turbo-diesel engine that produces 160PS, yet it has emissions of under 140 g/km CO2. Its efficiency is helped by its class leading aerodynamics, which give it a drag coefficient of just 0.26.
The Insignia ecoFLEX reaches 62mph in 9.5 seconds and a top speed of up to 135mph. Its torque can be temporarily increased for 15 seconds to 380Nm via an ‘overboost’ function.
The new 2.0-litre common-rail four-cylinder unit uses Vauxhall’s ‘Clean-Tech’ process to ensure the lowest possible emissions are precisely maintained over its life span.
This controls combustion via an electronic closed-loop system, adapting fuel injection to combustion development in real time. Piezo-resistive cylinder pressure sensors integrated in the glow plugs are used to measure combustion pressures as high as 180 bar in each individual cylinder up to one million times per minute, within an accuracy of ninety-eight percent.
The data is sent to the central engine control system, which adjusts the volume and timing of the fuel injections accordingly. This closed loop system ensures the engine always operates with optimum efficiency and minimal exhaust emissions.
Over the entire lifecycle of the Insignia, it compensates for wear factors such as inaccuracies in the fuel metering, component tolerances, varying fuel qualities and operating conditions.
Other factors contributing to the low consumption and emission figures include the 10 mm lower body to reduce the car’s frontal area, and the fitting of low-resistance Primacy HP tyres from Michelin. Like all Insignia models, the new ecoFLEX variant is Euro 5 certified and will be available as a hatchback and saloon in the second half of 2009 with prices announced closer to the launch.
The regular Insignia variants feature a drag factor of 0.27, however the Insignia ecoFLEX manages CD 0.26 which makes it one of the most aerodynamic production saloons in the world and the best Vauxhall saloon ever.
Vauxhall says that when doubling speed, the engine power necessary to overcome aerodynamic drag increases by a factor of eight. So if 13PS are necessary to overcome aerodynamic drag at 50mph, 107PS are needed at 100mph.
The aerodynamics of the Insignia ecoFLEX have been improved in many areas using traditional methods like adding panelling under the tank in front of the rear axle, which improves drag coefficient and increases downforce. They also partially closed the radiator grille to send more head-wind around the body for better aerodynamics.
Even the exterior mirror creates 45 per cent less aerodynamic drag compared to its predecessor.
During numerous computer simulations and more than 650 hours in the wind tunnel, numerous other details were fine-tuned for even better aerodynamic performance, including:
• adding a flexible front spoiler lip
• rounding front bumper corners
• slightly changing the windshield wiper position
• rounding the A-pillar
• ensuring roof air flows without separating
• integrating the rear spoiler lip
• integrating a separation edge into the tail lights
• separating the edge on the rear bumper
• optimising the shape of the lower control arm in the rear suspension
• adding a spoiler edge at end of door sill in front of rear wheels and wheel caps.
In the process, many of these modifications also benefited the Insignia’s aero-acoustics, resulting in an interior cabin that is quieter than any Vauxhall before.
“We designed the Insignia as a particularly efficient car from the beginning. By making a multitude of detailed improvements to the powertrain and to the road and wind resistance factors of the ecoFLEX model, our engineers are able to minimise fuel consumption without affecting driving fun,” says Hans Demant, Vice President of Global Engineering at General Motors Europe. “Though we are still developing the new Insignia ecoFLEX with the 2.0 CDTi ECOTEC engine, we are confident it will emit CO2 gases well below 140 g/km.”
The new Insignia ecoFLEX is another model to debut at the Paris Motor Show, October 4 – 19.