The new Aston Martin DB11 2+2 unveiled at the Geneva Show introduced a number of new features in an evolution of the V12-powered DB9. Aston Martin speaks of a new design language, while there is also a new twin-turbocharged 5.2-L V12 and a new aluminum structure claimed to be lighter, stronger and more space efficient.
There are some aerodynamic touches derived from Aston’s racecar program, LED lighting front and rear and innovative use of existing technologies.
The V12 is Aston’s most powerful engine to date and the first production Aston Martin to feature two turbochargers. It produces a claimed maximum power output of 447 kW (600 hp) at 6500 rpm and peak torque of 700 N·m (516 lb·ft) from 1500 – 5000 rpm. The V12 was designed by Aston Martin’s own powertrain team and is manufactured at the company’s engine facility.
Aston claims that it is also the most fuel-efficient engine the company has produced, using variable valve timing for both inlet and exhaust cams and stop-start technology. Perhaps more significantly, either bank of six cylinders can be deactivated when power is not in demand, i.e. when cruising, or lifting off or under light throttle openings. To ensure that emissions performance is maintained, catalytic converter temperature for both banks is constantly monitored.
If the catalyst for the de-activated bank of cylinders cools to its minimum operating temperature, the engine management system will automatically switch over, shutting down the active bank and simultaneously re-activating the inactive bank to bring catalyst temperatures up again.
Charge-air temperature is controlled by two water-to-air charge air coolers mounted on either side of the engine. Aston Martin says this type of cooler was chosen over air-to-air coolers because it offers the shortest charge air path to help minimize charge inertia and improve throttle response.
A ZF 8-speed torque converter automatic transmission with paddle shifts, mounted at the rear in a transaxle, transmits drive to the rear wheels. The transaxle incorporates a mechanical limited-slip differential with active torque vectoring—a first for Aston Martin. A pair of transfer gears are mounted at the rear of the differential. This means that the crown wheel can be located alongside the transmission, thereby shortening the transaxle assembly. This in turn means that the transmission can be mounted further to the rear, allowing a greater range of front seat adjustment.
The DB11 is constructed primarily from a mixture of bonded aluminum pressings, extrusions and castings. The clamshell bonnet is constructed from pressed aluminum, as are the roof and doors. In addition composite material is used for the rear quarters, front fenders and the rear decklid assembly. Injection molded plastic also played a part, being used for the front and rear bumpers, sills, as well as the front splitter and rear diffuser.
Compared with the DB9, the DB11 is 60 mm (2.3 in) longer in the wheelbase at 2805 mm (110,4 in) which, according to Aston Martin, enables the engine to be mounted further back in the chassis to improve the front/rear weight distribution. By comparison with the DB9, the car’s front track is said to be 75 mm (3 in) wider and 43 mm (1.7 in) wider at the rear.
Overall, the DB11 is 28 mm (1.1 in) wider than the DB9 and 50 mm (2 in) longer, although the front overhang is 16 mm (.62 in) shorter and the rear overhang is some 11 mm (.43 in) longer.
The door apertures are larger than on the DB9 because the A-pillar structures have been re-designed, while the sill sections have been made lower and narrower. This translates into 10 mm (.39 in) more headroom than before.
'Curlicue' and AeroBlade
The DB11 has adopted technologies from the company’s racecar program to help deal with the issues of downforce and reducing aerodynamic drag. The first of these is termed Curlicue, derived from the Aston Martin Vulcan track car.
This is a vent built into the top of each front wheel arch inner, designed to help reduce unwanted front aerodynamic lift. The vent directs high-pressure air through recessed apertures behind the side strakes, which feature on every Aston Martin model. A second vent at the rear of the front wheel arches extracts more air.
The second technique uses air ducted through the bodywork to reduce lift at the rear of the car. Intake slots incorporated in the base of the car’s C-pillars extract high-pressure air from the sides of the vehicle and channel it through the bodywork in contoured ducting. This is then vented through discreet slots in the rear deck lid. The resulting jet of disrupted air has the effect of reducing aerodynamic lift without the need for a rear spoiler that would compromise the shape at the rear of the car.
Aston Martin refers to this technique as the Aston Martin AeroBlade. That said, a small active spoiler is automatically activated when further downforce is needed at the rear, which will automatically retract at lower speeds.
Aston’s motorsport programs have also helped to shape the underside of the vehicle for optimized airflow. The front splitter, for instance, has been designed to manage cooling airflow through the radiator and balance this with the air directed beneath the car to feed through the rear diffuser.Continue reading »