This engine had a V-angle of 60 degrees, air cooling and an intake over exhaust (F-head) valve arrangement. įive years after the first V12 engine was introduced, Renault introduced the first V12 engine for aircraft in 1909. An example of a currently produced V12 marine engine is the Wärtsilä 46F engine, where the V12 version has a displacement of 1,157 L (70,604 cu in) and a power output of 14,400 kW (19,300 hp). Large V12 diesel engines are common modern cruise ships, which may have up to six such engines. In 1914, Panhard built two 38.6 L (2,356 cu in) V12 engines with four valves per cylinder, which were designed for use in racing boats. The Orleans Motor Company built a massive 56.8 L (3,464 cu in) flathead V12 engine with a power output quoted as "nearly 298 kW (400 bhp)". The Lamb Boat & Engine Company in the United States built a 25.5 L (1,559 cu in) engine for the company's 10 m (32 ft) 'Lamb IV' boat. Two more V12s appeared in the 1909-1910 motor boat racing season. The engine had a displacement of 18.4 L (1,120 cu in) a weight of 430 kg (950 lb) and developed 12 m (40 ft) racing boats, but little is known of its racing achievements. 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. Known as the "Craig-Dörwald" engine after Putney's founding partners, the V12 engine was based on Putney's existing two-cylinder engine with a flathead design, a V-angle of 90 degrees and an aluminium crankcase. These were followed by the first V12 engine in 1904, which was built by Putney Motor Works in London for use in racing boats. The first V-engine (a V-twin design) was built by Daimler in 1889, then the first V8 engine was built by Antoinette in 1903. In historic piston-engine fighter and bomber aircraft, the long, narrow V12 configuration used in high-performance aircraft made them more streamlined than other engines, particularly the short, wide radial engine. Large, fast cruise ships can have six or more V12 engines. In twin-propeller boats, two V12 engines can be narrow enough to sit side by side, while three V12 engines are sometimes used in high-speed three-propeller configurations. In these applications, the width of the engine is constrained by tight railway clearances or street widths, while the length of the vehicle is more flexible. Due to its narrower width, the V12 is common as locomotive, armoured tank, and marine engines. The added length often makes it difficult to fit a V12 engine into a passenger car, but the length is not typically a problem for trucks and stationary applications. However, the V12 engine is usually longer than V6 and V8 engines. However, the use of V12 engines in motor racing is uncommon in the 21st century.Ī 60-degree V12 engine is typically narrower than a 90-degree V6 or V8 engine of similar displacement. In addition, the exhaust system of a V12 engine is much simpler than would be required for a crossplane V8 engine to achieve pulsed exhaust gas tuning. Theoretically, the rotating parts of a V12 racing engine could be lighter than a crossplane V8 engine of similar displacement, due to the V12 engine not requiring counterweights on the crankshaft or as much inertial mass for the flywheel. However, this terminology is incorrect for the majority of 180-degree V12 engines, since they use shared crankpins and are therefore not configured as boxer engines. The drawbacks of V12 engines include extra cost, complexity, friction losses, and external size and weight, compared with engines containing fewer cylinders.Īt any given time, three of the cylinders in a V12 engine are in their power stroke, which increases the smoothness of the power delivery by eliminating gaps between power pulses.Ī V12 engine with a 180 degree V-angle is often called a flat-twelve engine (or a 'boxer twelve'). V12 engines with other V-angles have been produced, sometimes using split crankpins to reduce the unbalanced vibrations. Many V12 engines use a V-angle of 60 degrees between the two banks of cylinders. The even firing order for a four-stroke V12 engine has an interval of 60 degrees, therefore a V12 engine can be perfectly balanced only if a V-angle of 60 degrees is used. By using the correct V-angle, a V12 engine can therefore have a perfect balance. Design Balance and smoothness Įach bank of a V12 engine essentially functions as a straight-six engine, which by itself has perfect primary and secondary engine balance.
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