Opel will introduce a new BiTurbo engine on the Insignia beginning in January 2012. The 2.0-liter CDTI power delivers 143 kW (195 hp) and 400 N·m (295 lb-ft) of torque, with a fuel consumption rating of 4.9 liters per 100 kilometers (48 mpg US), or 129 g/km CO2, in the front-wheel-drive notchback version. All versions with manual transmission are also equipped with Start/Stop.
The main focus in the development in the 2.0 CDTI BiTurbo engine was to ensure a rapid build-up of charge air pressure in the low-rpm range, while giving the accelerator added responsiveness in the mid-rpm range. The engine air is ideally adjusted according to the rpm range and the needs of the two turbochargers of different size.
In the Insignia’s BiTurbo system, two turbochargers of different sizes work either separately or together. The smaller turbocharger accelerates especially quickly at low engine speeds. This means the accelerator pedal responds without delay and the undesired “turbo lag” effect is prevented. Starting at 1500 rpm, the driver can already draw on 350 N·m.
In the mid-range of rpm both turbochargers operate together, with the larger turbocharger pre-compressing the intake air, before it is fully compressed in the smaller one. A bypass valve is controlled continuously to pass on part of the exhaust gases to the larger turbo. As a result, the driver continues to enjoy powerful acceleration.
At higher rpm (from around 3000 rpm) all the gases flow directly to the larger turbocharger, maintaining the fluid power delivery at higher speeds.
The main focus in the development in the 2.0 CDTI BiTurbo engine was to ensure a rapid build-up of charge air pressure in the low rpm range, while giving the accelerator added responsiveness in the mid rpm range. The engine air is adjusted according to the rpm range and the needs of the two turbochargers of different size.
At low rpms an additional, water-cooled intercooler that is exclusively linked to the small turbocharger ensures that the small volume of air passes in a short and direct path to the combustion chamber. In the mid rpm range, the bigger and more powerful turbocharger becomes increasingly involved. Its larger stream of air is cooled by the bigger, conventional intercooler. Opel is the first car brand to use such a “twin cooler system”.
Opel has further optimized its engine efficiency by employing its Cleantech technology which controls the combustion process via a closed loop electronic circuit. Sensors fitted to the glow plugs measure the pressure 130,000 times per minute, ensuring that the engine always operates in the optimum window of maximum performance, as well as minimum fuel consumption and CO2 emissions. The third generation Common Rail direct injection runs at pressures of up to 2,000 bar with piezoelectrically activated nozzles delivering up to eight injections per work cycle.
With the new top-of-the-line 2.0 CDTI BiTurbo, the Opel Insignia range now offers a range of four common-rail direct injection turbo diesels with power outputs ranging from 81 kW/110 hp to 143 kW/195 hp.
The BiTurbo technology has so far been limited to higher priced brands, Opel notes. Buyers have the option to combine the new engine with front or all-wheel drive (AWD). The Insignia 2.0 BiTurbo CDTI is available in all body styles starting at €33,405 (US$45,000).