|The 407 with 2.2 HDi
Peugeot is introducing the new 2.2-liter, four-cylinder HDi sequential dual-turbo for its 407 sedan and wagon. The engine, announced last year, represents the fourth phase of cooperation between PSA Peugeot Citroën and Ford Motor Company. (Earlier post.)
The new engine delivers 125 kW of power (170 hp) at 4,000 rpm and 370 Nm of torque at 1,500 rpm—54% more than the previous generation of 2.2-liter HDi engines at this engine speed. Acceleration from 0-62 mph takes 8.7 seconds.
Mated with a six-speed manual transmission, the 2.2 HDi offers fuel consumption of 6.1 liters/100km on the combined cycle (38.6 mpg US) and emits 160 g CO2/km.
The engine features a sequential, parallel dual-turbo system—the first on a four-cylinder engine—patented with Honeywell Turbo Technology; a new type of combustion chamber; and third-generation common rail injection with pressure to 1,800 bar.
|The dual turbo. Click to enlarge.
Dual Turbo. At low engine speeds, a single turbocharger ensures engine responsiveness. It is then supported by a second turbo, which starts to operate in parallel between 2,600 and 3,200 rpm according to the required load and atmospheric conditions. This covers the entire range of engine speeds. The system is controlled entirely by the engine ECU.
The low inertia resulting from the small size of the turbos reduces response time when they start to operate.
Combustion chamber. The Extreme Conventional Combustion System (ECCS) is characterized by a reduced compression ratio (16.6 compared to 18 previously) and a larger diameter (+25%), helping to reduce the quantity of incompletely burned fuel by limiting the proportion of fuel in contact with the walls.
This effect is obtained as a result of a special piston design and geometry (manufactured from aluminium with a very high mechanical strength and thermal resistance). This geometry also makes it possible to significantly reduce swirl by limiting thermal losses against the walls.
These developments allow greater homogeneity of the air-fuel blend, resulting in a significant improvement to the engine’s overall efficiency, as well as quieter combustion.
Injection system. The third-generation Bosch common rail injection system supports a pressure increase to 1,800 bar, compared to 1,350 bar for the first generation. New piezo-electric injectors have seven apertures (instead of five previously) with a diameter of 135 microns, allowing the number of injections to be multiplied (potentially up to six per cycle) and ensuring uniformity of the diesel spray.
This optimized air/diesel blend helps combustion be more complete and uniform, and reduces emissions at the source. The combination of the new combustion chamber and 1,800-bar common rail system support a reduction of emissions of around 30% compared to the previous generation. The new 2.2 HDi is equipped with a particulate filter and is Euro-4 compliant.