Extended Version: The new twelve-cylinder and the new ISR transmission – Innovative technologies for a unique powertrain
Automobili Lamborghini is embarking on a highly innovative chapter in the company’s history with an all-new V12 power plant and a new, unique high performing seven speed transmission: The twelve-cylinder with 6.5 liters displacement, output of 525 kW (700 hp) and maximum torque of 690 Newton meters was developed with state-of-the-art technology from a white sheet of paper. The result is a synthesis of breathtaking performance, high-revving exhilaration, low weight and moderate gas emissions. The perfect complement is a completely new transmission concept for super sports cars: The “Lamborghini ISR” automated manual gearbox combines minimal shift times and everyday convenience with low weight and dimensions to guarantee the emotional gearshift that customers expect from a super sports car at the very top of the premier league. The new powertrain will enter production early 2011.
The legend of Lamborghini strongly relies on its extraordinary, unique V12 engines.“This new power unit is not only the crowning glory of our product lineup, it is also part of our enormous investment in the future of the Lamborghini brand,” says Stephan Winkelmann, President and CEO of Automobili Lamborghini. “With this new V12, we are heralding a technological leap that encompasses all areas of the company and our future model range. With a unique package of innovations, Lamborghini will redefine the future of the super sports car. This 700 hp engine, together with an all-new concept gearbox, will be at the heart of the Murciélago successor next year.”
The new V12 power unit –
The heart of Lamborghini
The twelve-cylinder is the king of the engine world and the true heart of the Lamborghini brand. The very first model created by Feruccio Lamborghini, the 350 GT, made its appearance in 1964 featuring a twelve-cylinder engine that was incredibly innovative for its day. 3.5 liter displacement and 320 hp were the vital statistics back then – they formed the basis for ongoing increases and further development over the decades that followed. Miura, Espada, Countach, Diablo and, finally, Murciélago are just a few of the super sports cars born in Sant’Agata. All of them were, and will continue to be, driven by V12 engines – and all have long since risen to the status of automotive legend.
Now the next milestone in this glorious history appears – engineers in the Lamborghini R&D Department have developed a completely new high-performance power unit. That it would be another twelve-cylinder was never in doubt - and not only because of the special magic conjured up by the number twelve. The only real choice for Lamborghini is a high-revving naturally aspirated engine – the deeply reflexive and exceptionally powerful reaction of the automobile to the tiniest movement of the driver’s right foot is, of course, a key part of the whole fascination inspired by a super sports car. Ten cylinders are ideal in the displacement class around the five liter mark, as evidenced by the highly acclaimed Gallardo engine. For the 6.5 liter displacement targeted in this case, the perfect number is twelve. A lower number of cylinders would result in larger and heavier pistons and con-rods, which would have a negative impact on the engine’s high-revving characteristics.
Starting with a clean sheet of paper
The specification for the development of the new twelve-cylinder, known internally as the L539, was written quickly – yet was highly demanding in its formulation. Naturally, it had to deliver more power and torque than its predecessor in the Murciélago, but it should also be smaller and lighter and enable a lower center of gravity. At the end of the day, low weight is just as important to the performance of a super sports car as high power output. Fuel consumption and gas emissions should also be reduced significantly.
So the R&D team started with a clean sheet of paper – metaphorically speaking, of course. Design and development in Sant’Agata is conducted using state-of-the-art systems and equipment. The outcome is a V12 with a classic cylinder bank angle of 60 degrees, and thus an amazingly compact power package – the power unit measures only 665 millimeters from top to bottom, including the intake system. Its width, including the exhaust manifold, is only 848 millimeters, while its length is a mere 784 millimeters. Its weight of 235 kilograms is also respectably low – each kilogram of engine weight corresponds to 3.0 HP maximum output.
Optimized for high revving and low weight
The crankcase on the new power plant is made from an aluminum-silicon alloy and has an open-deck construction with steel cylinder liners. Displacement is 6,498 cm3 and cylinder spacing 103.5 millimeters, while bore diameter measures 95 millimeters and stroke 76.4 millimeters. The short-stroke layout is especially good for high-revving characteristics and for low internal friction. Particular attention was also paid to the bearings for the forged and nitride-hardened crankshaft, which weighs in at 24.6 kilograms.
The two four-valve cylinder heads are likewise made from sand-cast aluminum-silicon alloy, each weighing a very light 21 kilograms. The twelve pistons and con-rods are, respectively, in forged alloy and steel. The maximum piston speed at 8,250 rpm is only 21 meters per second, which is considerably less than for the Murciélago’s previous power unit. The combustion chambers were carefully engineered to achieve optimum tumble and combustion of the fuel/air mixture. At 11.8:1, the compression ratio is extremely high. Inlet and outlet valve timing is electronically controlled.
Sophisticated thermal management, optimized oil circulation
The thermal management of this high-performance power unit was perfected with extensive detail engineering. Two switchable water circuits in the engine ensure very rapid warm-up, which minimizes friction and quickly brings the catalytic converters up to operating temperature, thus benefiting fuel consumption and emissions. The external water coolers are switched into the circuit only as required.
Absolute engine health, even under extreme racetrack conditions with high lateral acceleration, is guaranteed by oil circulation using a dry sump system. A total of eight scavenger pumps suck oil out of the lower bedplate fastened to the crankcase. Pressure and scavenging losses are thus reduced by around 50 percent. A high-pressure oil pump maintains lubrication, while an oil/water cooler and an oil/air radiator constantly keep temperatures within range even under extremely high load. A further benefit of this form of dry sump lubrication is the very low mounting position of the engine within the sports car. The new engine is mounted 60 millimeters lower than the V12 in the Murciélago – with the associated benefits in respect of center of gravity and lateral dynamics.
From the outside, the V12 is dominated by its intake system – which incorporates four individual throttle valves. Life inside the black housing is also extremely complex – the optimum intake path for any given load and engine speed is facilitated by two flaps, several channels and one bypass. The payback is an extremely well-rounded torque curve and refined pulling power throughout the rev range.
Mighty orchestra for twelve voices
The exhaust system, too, was afforded the undivided attention of Lamborghini’s engineers – the lowest possible gas emissions was just as important a target as the unmistakable, spine-tingling Lamborghini sound. The hydro-formed and thermally insulated three-into-one system incorporates four pre-catalytic converters close to the engine and two main catalytic converters shortly before the muffler. The casing incorporates two separate mufflers – one low-volume, one high-volume. Regulated by valves controlled via the engine management, they handle all the elements of the big twelve-cylinder symphony – from a moderate rumble when rolling through the city at low revs to the screaming crescendo of maxed-out gear shifts.
Electronics devised entirely by Lamborghini
Another highlight is the electronic engine management, which was developed in its entirety by engineers at Lamborghini. The system consists of the main ECU, a secondary “smart actuators” and two additional black boxes that function as “smart sensors”. Because speed is everything for an engine like this, some ECU control and connection functions are handled by the smart actuators, making the ECU faster. The two smart sensors are constantly monitoring combustion in real time – each ignition in every cylinder. The spark plugs – each is powered by an individual ignition coil – function as “sensors”; the two auxiliary control units monitor the power signal after every ignition and can immediately identify irregularities in the combustion process through ionization phenomena. This data is used to continually optimize engine management, benefiting both performance and fuel consumption.