RIDE OR DIE: V12 ENGINE

In the beginning, there was the V12. Designed by Giotto Bizzarrini for ambitious tractor magnate Ferruccio Lamborghini, Bizzarini's V12 was fitted to the first Lamborghini, the handsome 1963 350GT. Was that first Lamborghini engine based on Bizzarrini's 1.5-liter Grand Prix screamer, or Honda's similar unit, as suggested by L.J.K. Setright in 1973? Does it matter? And, besides, who would dare ask?

"I know Giotto," said Maurizio Reggiani, Lamborghini's R&D chief. "I've never asked him—there's a thing about respect..."
Reggiani was introducing the new V12, fifth in line from that Bizzarrini original, which has been progressively redesigned over the years and fitted to Formula One cars, offshore-racing powerboats and successive Lamborghini supercars: the Miura, the Countach, the Diablo and the Murciélago.
The new engine follows the pattern of a 60-degree V12 with double overhead camshafts, but the car it will be fitted into, the Murciélago replacement, won't be seen until next spring's Geneva Motor Show. We have a clue as to what it will look like, however, with the all-carbon-fiber Sesto Elemento (Sixth Element) concept car from September's Paris Motor Salon.

"With this new V12, we are heralding a technological leap that encompasses all areas of the company and our future model range," said Stephan Winkelmann, president and CEO of Automobili Lamborghini. "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 Specs

While the novelty of an all-new V12 engine is intriguing, especially in this age of tighter fuel-economy regulations, the really startling thing about this unit is that Lamborghini has unapologetically stayed with a naturally aspirated engine with conventional port fuel injection rather than adopting the direct injection route taken by its VW-owned sister company, Audi. In other words, at a time when rivals such as Ferrari are seriously talking about smaller-displacement turbocharged, direct-fuel-injected engines, Lamborghini is not just producing a naturally aspirated V12, but it is also an old-school, short-stroke, big-block screamer. The introduction to the engine consisted of a video of the unit singing its heart out at 8,500 rpm on the dynamometer at the company's base in Sant'Agata, near Bologna, Italy. This was a mechanical aria of a premier engine.

The new engine is made of aluminium–silicon alloy, with an open-deck construction and steel cylinder liners. It has a forged steel crankshaft, with twin overhead camshafts and variable timing. At the top end, inlet air is drawn through four throttle bodies into a plenum chamber with internal valves that change the volume, optimizing airflow at a variety of engine speeds. There are two cooling circuits: a small volume system to speed warmup and reduce cold-start emissions, and a larger system for high-temperature control. The exhaust also has valves that open at high revs to divert the flow through a low-restriction (and noisier) muffler.

With a 95-millimeter bore and 76.4-millimeter stroke (the old engine measured 88 and 89 millimeters, respectively), the new motor displaces 6.5 liters. The short-stroke design means this engine was made to rev, and its 700-hp power peak spikes at a lofty 8250 rpm. Torque is likewise strong—509 lb-ft—but that figure also occurs high up in the rev range, 5500 rpm.

Lamborghini claims a "clean sheet" design for the engine, which used several bits of interesting technology. Each pair of pistons runs in its own sealed chamber, which is served by its own scavenge pump—there are eight in all. Each chamber acts as its own air spring, so the downward movement of one piston pushes the opposing piston on the same crankpin upward in opposing vee, reducing frictional losses. It's also a dry-sump design so the engine could be mounted lower in the frame, improving weight distribution for better handling.

Of course, modern electronics are part of the package. And the computer controls nearly everything, including the throttle and even the robotized six-speed transmission and clutch.

The Transmission

Like the Murciélago, the new supercar will be four-wheel drive, via a central electrohydraulically controlled Haldex center coupling. Unlike Ferrari and the VW Group, which utilize dual-clutch automated gearboxes (DSG), Lamborghini is persevering with a robotized single-clutch manual transmission made by Graziano that's operated either automatically or via steering-wheel- mounted paddles. While Lamborghini claims this transmission is lighter and more compact, we generally prefer the smoothness of DSGs. Known as the ISR (independent shifting rods) transmission, the seven-speed (plus reverse) gearbox uses integral plumbing in the casing to actuate shifts. The unit has carbon-fiber synchros. Shift times have been reduced by up to 50 percent, and Lamborghini claims that in its fastest, or Corsa mode, shift times can be as low as 50 milliseconds.
The Bottom Line

While the rest of the world contemplates life without even V8 engines, Lamborghini is unveiling its most outrageous power unit yet. What's more, the company claims the unit will meet all current and next-generation emissions and fuel-consumption regulations. It wouldn't be an option available to a mass-market carmaker, of course, but we're delighted that this motorsport- inspired V12 is far from dead. Giotto Bizzarrini must be delighted.

A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders, usually but not always at a 60° angle to each other, with all 12 pistons driving a common crankshaft.

Since each cylinder bank is essentially a straight-6, this configuration has perfect primary and secondary balance no matter which V angle is used and therefore needs no balance shafts. A V12 with two banks of six cylinders angled at 60°, 120° or 180° (with the latter configuration usually referred to as a flat-12) from each other has even firing with power pulses delivered twice as often per revolution as a straight-6. This allows for great refinement in a luxury car. In a racing car, the rotating parts can be made much lighter and thus more responsive, since there is no need to use counterweights on the crankshaft as is needed in a 90° V8 and less need for the inertial mass in a flywheel to smooth out the power delivery. In a large displacement, heavy-duty engine, a V12 can run slower than smaller engines, prolonging engine life.

Early (pre WW1) V12 engines

Marine engines

The first V-type engine (a 2-cylinder vee twin) was built in 1889 by Daimler, to a design by Wilhelm Maybach. By 1903 V8 engines were being produced for motor boat racing by the Société Antoinette to designs by Léon Levavasseur, building on experience gained with in-line four-cylinder engines. In 1904, the Putney Motor Works completed a new V12 marine racing engine – the first V12 engine produced for any purpose. Known as the ‘Craig-Dörwald’ engine after Putney’s founding partners, the engine mounted pairs of L-head cylinders at a 90 degree included angle on an aluminium crankcase, using the same cylinder pairs that powered the company’s standard 2-cylinder car. A single camshaft mounted in the central vee operated the valves directly. As in many marine engines, the camshaft could be slid longitudinally to engage a second set of cams, giving valve timing that reversed the engine’s rotation to achieve astern propulsion. "Starting is by pumping a charge into each cylinder and switching on the trembler coils. A sliding camshaft gave direct reversing. The camshaft has fluted webs and main bearings in graduated thickness from the largest at the flywheel end." Displacing 1,119.9 cuin (18,352 cc) (bore and stroke of 4.875" x 5" (123.8 x 127 mm)), the engine weighed 950 pounds (430 kg) and developed 150 bhp (110 kW). Little is known of the engine's achievements in the 40-foot hull for which it was intended, while a scheme to use the engine to power heavy freight vehicles never came to fruition. One V12 Dörwald marine engine was found still running in a Hong Kong junk in the late-1960s.
Two more V12s appeared in the 1909-10 motor boat racing season. The Lamb Boat & Engine Company of Clinton, Iowa built a 1,558.6 cuin (25,541 cc (5.25" x 6" (133.4 x 152.4 mm)) engine for the company’s 32-foot Lamb IV. It weighed in at 2,114 pounds (959 kg). No weight is known for the massive 3,463.6 cuin (56,758 cc) (7" x 7.5" (177.8 x 190.5 mm)) F-head engine built by the Orleans Motor Company. Output is quoted as “nearly 400 bhp (300 kW)”.
By 1914, when Panhard built two 2,356.2 cuin (38,611 cc) (5" x 10" (127 x 254 mm)) engines with four-valve cylinder heads the V12 was well established in motor boat racing.

Motor car engines

In October 1913 Louis Coatalen, chief engineer of the Sunbeam car company entered a V12 powered car in the Brooklands short and long handicap races. The engine displaced 9,048 cc (552.1 cuin), with bore and stroke of 80 x 150 mm. An aluminium crankcase carried two blocks of three cylinders along each side, with a 60 degree included angle. The cylinders were of iron, with integral cylinder heads with L-shaped combustion chambers. Inlet and exhaust valves were operated by a central camshaft in the vee. Valve clearance was set by grinding the relevant parts, the engine lacking any easy means of adjustment. This pointed to Coatalen’s ultimate aim of using the new V12 as an aero engine, where any adjustment method that could go wrong in flight was to be avoided. As initially built the V12 was rated at 200 bhp (150 kW) at 2,400 rpm, weighing about 750 pounds (340 kg). The engine powered the car (named ‘Toodles V’ (for Coatalen’s wife Olive’s pet name) to several records in 1913 and 1914.

Early aero engines

In 1909 Renault pioneered aero V12s with a 60 degree air-cooled engine with individual finned cylinders and F-head valve arrangement, driven by single camshaft in the crankcase. This was developed to a 12,160 cc (742.1 cuin) unit (96 x 140 mm) which weighed 772 pounds (350 kg) and produced 138 bhp (103 kW) at 1,800 rpm. The propeller was driven from the nose of the camshaft in the central vee, rather than from the crankshaft, thus providing an automatic half-speed reduction, improving propeller efficiency.
Renault’s designs were closely followed in Britain by the Royal Aircraft Factory. Its RAF 4 engine displaced 13,195 cc (805.2 cuin)(100 x 140 mm), produced 140 bhp (100 kW) at 1,800 rpm, for a weight of 637 pounds (289 kg). Its RAF 4a derivative was produced in substantial numbers during the war.
By 1912 ABC were offering a water-cooled engine of 17,375 cc (1,060.3 cuin), claimed to produce 170 bhp (130 kW) at 1,400 rpm and weigh 390 pounds (180 kg) – 520 pounds (240 kg) with radiator and coolant.

In March 1914 Sunbeam exhibited an airborne version of Toodles V’s engine at Olympia. Racing in 1913 had helped to prove the design, and encouraged a 10 mm increase in bore to 90 m, the stroke remaining at 150 mm. Its rated output was 225 bhp (168 kW) at 2,000 rpm. Named the ‘Mohawk’, the engine was the most powerful available to British aviation at the outbreak of WW1. During the war further enlargement to 100 x 150 mm created the 240 bhp (180 kW) ‘Gurkha’.

Later V12s in aviation

By the end of World War I, V12s were well established in aviation, powering some of the newest and largest fighters and bombers and being produced by companies such as Renault and Sunbeam. Many Zeppelins had 12-cylinder engines from German manufacturers Maybach and Daimler. Various U.S. companies produced the Liberty L-12. Soon after the end of WW1 V12 engines powered the first trans-atlantic crossings by the Curtiss NC Flying boats (4 x Liberty L-12), the first non-stop crossing by Alcock and Brown in a Vickers Vimy (2× Rolls-Royce Eagles and the first airship crossing by HM airship R-34 (5× Sunbeam Maori).

V12 engines reached their apogee during World War II. Fighters and bombers used V12 engines such as the British Rolls-Royce Merlin and Griffon, the Soviet Klimov VK-107 and Mikulin AM-38, the American Allison V-1710, or the German Daimler-Benz DB 600 series and Junkers-Jumo. These engines generated about 1,000 hp (750 kW) at the beginning of the war and above 1,500 hp (1,100 kW) at their ultimate evolution stage. The German DB 605D engine reached 2,000 hp (1,500 kW) with water injection. In contrast to most Allied V12s, the engines built in Germany by Daimler-Benz, Junkers-Jumo, and Argus (As 410 and As 411) were primarily inverted, which had the advantages of lower centers of gravity and improved visibility for single-engined designs. Only the pre-war origin BMW VI V12 of Germany was an "upright" engine. The United States had the experimental Continental IV-1430 inverted V12 engine under development, with a higher power-to-weight ratio than any of the initial versions of the German WW II inverted V12s, but was never developed to production status, with only 23 examples of the Continental inverted V12 ever being built. The only American-design inverted V12 engine of any type to see even limited service in World War II was the air-cooled Ranger V-770, which found use in stateside-based training aircraft like the Fairchild AT-21 Gunner twin-engined "advanced" trainer.

The Rolls-Royce Merlin V12 powered the Hawker Hurricane and Supermarine Spitfire fighters that played a vital role in Britain's victory in the Battle of Britain. The long, narrow configuration of the V12 contributed to good aerodynamics, while its smoothness allowed its use with relatively light and fragile airframes. The Merlin was also used in the Avro Lancaster and de Havilland Mosquito bombers. In the United States the Packard Motor company was licensed by Rolls-Royce to produce the Merlin as the Packard V-1650 for use in the North American P-51 Mustang. It was also incorporated into some models of the Curtiss P-40, specifically the P-40F and P-40L. Packard Merlins powered Canadian-built Hurricane, Lancaster, and Mosquito aircraft, as well as the UK-built Spitfire Mark XVI, which was otherwise the same as the Mark IX with its British-built Merlin.

The Allison V-1710 was the only indigenous U.S.-developed V12 liquid-cooled engine to see service during World War II. A sturdy design, it lacked an advanced mechanical supercharger until 1943. Although versions with a turbosupercharger provided excellent performance at high altitude in the Lockheed P-38 Lightning, the turbosupercharger and its ductwork were too bulky to fit into typical single-engine fighters. While a good performer at low altitudes, without adequate supercharging, the Allison's high-altitude performance was lacking.
After World War II, V12 engines became generally obsolete in aircraft due to the introduction of turbojet and turboprop engines that had more power for their weight, and fewer complications.