Formula One currently uses 1.6 litre four-stroke turbocharged 90 degree V6 reciprocating engines.[1] The power a Formula One engine produces is generated by operating at a very high rotational speed, up to 15,000 revolutions per minute (RPM).[2] This contrasts with road car engines of a similar size which typically operate at less than 6,000 rpm. The basic configuration of a naturally aspirated Formula One engine had not been greatly modified since the 1967 Cosworth DFV and the mean effective pressure had stayed at around 14 bar MEP.[3] Until the mid-1980s Formula One engines were limited to around 12,000 rpm due to the traditional metal valve springs used to close the valves. The speed required to operate the engine valves at a higher RPM called for ever stiffer springs, which increased the power loss to drive the camshaft and the valves to the point where the loss nearly offset the power gain through the increase in rpm. They were replaced by pneumatic valve springs introduced by Renault,[4][5] which inherently have a rising rate (progressive rate) that allowed them to have extremely high spring rate at larger valve strokes without much increasing the driving power requirements at smaller strokes, thus lowering the overall power loss. Since the 1990s, all Formula One engine manufacturers used pneumatic valve springs with the pressurised air allowing engines to reach speeds of nearly 20,000 rpm.[5] In addition to the use of pneumatic valve springs a Formula One engine's high RPM output has been made possible due to advances in metallurgy and design allowing lighter pistons and connecting rods to withstand the accelerations necessary to attain such high speeds, also by narrowing the connecting rod ends allowing for narrower main bearings. This allows for higher RPM with less bearing-damaging heat build-up. For each stroke, the piston goes from a null speed, to almost two times the mean speed, (approximately 40 m/s) then back to zero. This will occur four times for each of the four strokes in the cycle. Maximum piston acceleration occurs at top dead center and is in the region of 95,000 m/s2, about 10,000 times standard gravity or 10,000 g. In 1966, with sports cars capable of outrunning Formula 1 cars thanks to much larger and more powerful engines, the FIA increased engine capacity to 3.0 L atmospheric and 1.5 L compressed engines. Although a few manufacturers had been clamouring for bigger engines, the transition wasn't smooth and 1966 was a transitional year, with 2.0 L versions of the BRM and Coventry-Climax V8 engines being used by several entrants. The appearance of the standard-produced Cosworth DFV in 1967 made it possible for small manufacturers to join the series with a chassis designed in-house. Compression devices were allowed for the first time since 1960, but it wasn't until 1977 until a company actually had the finance and interest of building one, when Renault debuted their new Gordini V6 Turbo at the British Grand Prix at Silverstone that year. It was in 1980 that Renault proved that turbocharging was the way to go in order to stay competitive in Formula One (particularly at high-altitude circuits like Kyalami in South Africa and Interlagos in Brazil) ; this engine had a considerable power advantage against the Ford-Cosworth DFV, Ferrari and Alfa Romeo naturally aspirated engines. Following this, Ferrari introduced their all-new turbocharged engine in 1981. Following these developments, Brabham owner Bernie Ecclestone managed to get BMW to make the team turbocharged inline-4 engines from 1982 onwards. And in 1983, Alfa Romeo made a turbocharged V8 engine, and in the same year and following years, Honda, Porsche (badged as TAG), Ford-Cosworth and other smaller companies made turbo-charged engines, mostly twin-turbocharged V6's. By the midpoint of 1985, every competing team had a turbocharged engine in their car. And by 1986, the power figures were becoming quite crazy- all of the engines had unrestricted turbo boost in qualifying, where they were developing 1,350+ hp at 5.5 bar boost (80 psi). These engines and gearboxes would only last about 2-3 laps, and for the race, the turbocharger's boost was restricted to ensure engine reliability; but the engines still produced 950-1000 hp during the race. Following their experiences at Indianapolis, in 1971 Lotus made a few unsuccessful experiments with a Pratt & Whitney turbine fitted to chassis which had also 4WD. The power range was between 390 hp (290 kW) to 500 hp (370 kW), turbos 500 hp (370 kW) to 900 hp (670 kW) in race, in qualifying up to 1,300 hp (970 kW).

• published: 16 Sep 2014
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