163-410: In an internal combustion engine , a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement . The current categorization is that a supercharger is a form of forced induction that is mechanically powered (usually by a belt from the engine's crankshaft ), as opposed to a turbocharger , which is powered by the kinetic energy of
326-433: A carburetor or fuel injection as port injection or direct injection . Most SI engines have a single spark plug per cylinder but some have 2 . A head gasket prevents the gas from leaking between the cylinder head and the engine block. The opening and closing of the valves is controlled by one or several camshafts and springs—or in some engines—a desmodromic mechanism that uses no springs. The camshaft may press directly
489-434: A combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high- temperature and high- pressure gases produced by combustion applies direct force to some component of the engine. The force is typically applied to pistons ( piston engine ), turbine blades ( gas turbine ), a rotor (Wankel engine) , or a nozzle ( jet engine ). This force moves
652-409: A deflector head . Pistons are open at the bottom and hollow except for an integral reinforcement structure (the piston web). When an engine is working, the gas pressure in the combustion chamber exerts a force on the piston crown which is transferred through its web to a gudgeon pin . Each piston has rings fitted around its circumference that mostly prevent the gases from leaking into the crankcase or
815-428: A gas engine . Also in 1794, Robert Street patented an internal combustion engine, which was also the first to use liquid fuel , and built an engine around that time. In 1798, John Stevens built the first American internal combustion engine. In 1807, French engineers Nicéphore Niépce (who went on to invent photography ) and Claude Niépce ran a prototype internal combustion engine, using controlled dust explosions,
978-470: A locomotive operated by electricity.) In boating, an internal combustion engine that is installed in the hull is referred to as an engine, but the engines that sit on the transom are referred to as motors. Reciprocating piston engines are by far the most common power source for land and water vehicles , including automobiles , motorcycles , ships and to a lesser extent, locomotives (some are electrical but most use diesel engines ). Rotary engines of
1141-479: A "universal" propeller shaft, allowing either de Havilland or Rotol manufactured propellers to be used. The first major version to incorporate changes brought about through experience in operational service was the XX, which was designed to run on 100- octane fuel. This fuel allowed higher manifold pressures , which were achieved by increasing the boost from the centrifugal supercharger . The Merlin XX also utilised
1304-940: A Merlin X with a two-speed supercharger in high gear generated 1,150 hp (860 kW) at 15,400 feet (4,700 m) and 1,160 hp (870 kW) at 16,730 feet (5,100 m). From late 1939, 100-octane fuel became available from the U.S., West Indies , Persia , and, in smaller quantities, domestically, consequently, "... in the first half of 1940 the RAF transferred all Hurricane and Spitfire squadrons to 100 octane fuel." Small modifications were made to Merlin II and III series engines, allowing an increased (emergency) boost pressure of +12 pounds per square inch (183 kPa; 1.85 atm). At this power setting these engines were able to produce 1,310 hp (980 kW) at 9,000 ft (2,700 m) while running at 3,000 revolutions per minute. Increased boost could be used indefinitely as there
1467-594: A battery and charging system; nevertheless, this system is secondary and is added by manufacturers as a luxury for the ease of starting, turning fuel on and off (which can also be done via a switch or mechanical apparatus), and for running auxiliary electrical components and accessories. Most new engines rely on electrical and electronic engine control units (ECU) that also adjust the combustion process to increase efficiency and reduce emissions. Surfaces in contact and relative motion to other surfaces require lubrication to reduce wear, noise and increase efficiency by reducing
1630-621: A build-up of lead in the combustion chambers, causing excessive fouling of the spark plugs . Better results were achieved by adding 2.5% mono methyl aniline (M.M.A.) to 100-octane fuel. The new fuel allowed the five-minute boost rating of the Merlin 66 to be raised to +25 pounds per square inch (272 kPa; 2.7 atm). With this boost rating the Merlin 66 generated 2,000 hp (1,500 kW) at sea level and 1,860 hp (1,390 kW) at 10,500 ft (3,200 m). Starting in March 1944,
1793-404: A carefully timed high-voltage to the proper cylinder. This spark, via the spark plug, ignites the air-fuel mixture in the engine's cylinders. While gasoline internal combustion engines are much easier to start in cold weather than diesel engines, they can still have cold weather starting problems under extreme conditions. For years, the solution was to park the car in heated areas. In some parts of
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#17327978130631956-526: A car’s exhaust note, while a supercharged engine maintains the louder exhaust note of a normally aspirated car. Turbocharged engines are more prone to heat soak of the intake air (since turbocharging can place the hot exhaust components near the intake air system), although this can be overcome through the use of an intercooler . The majority of aircraft engines used during World War II used mechanically driven superchargers because they had some significant manufacturing advantages over turbochargers. However,
2119-499: A common power source for lawnmowers , string trimmers , chain saws , leafblowers , pressure washers , snowmobiles , jet skis , outboard motors , mopeds , and motorcycles . There are several possible ways to classify internal combustion engines. By number of strokes: By type of ignition: By mechanical/thermodynamic cycle (these cycles are infrequently used but are commonly found in hybrid vehicles , along with other vehicles manufactured for fuel efficiency ): The base of
2282-523: A dynamic compressor are: Common methods of driving a supercharger include: Fuels with a higher octane rating are better able to resist autoignition and detonation . As a result, the amount of boost supplied by the superchargers could be increased, resulting in an increase in engine output. The development of 100-octane aviation fuel, pioneered in the USA in the 1930s, enabled the use of higher boost pressures to be used on high-performance aviation engines and
2445-617: A form of internal combustion engine, though of a type so specialized that they are commonly treated as a separate category, along with weaponry such as mortars and anti-aircraft cannons.) In contrast, in external combustion engines , such as steam or Stirling engines , energy is delivered to a working fluid not consisting of, mixed with, or contaminated by combustion products. Working fluids for external combustion engines include air, hot water, pressurized water or even boiler -heated liquid sodium . While there are many stationary applications, most ICEs are used in mobile applications and are
2608-452: A hand crank. Larger engines typically power their starting motors and ignition systems using the electrical energy stored in a lead–acid battery . The battery's charged state is maintained by an automotive alternator or (previously) a generator which uses engine power to create electrical energy storage. The battery supplies electrical power for starting when the engine has a starting motor system, and supplies electrical power when
2771-461: A higher altitude of over 19,000 ft (5,800 m); and also improved the design of both the impeller, and the diffuser which controlled the airflow to it. These modifications led to the development of the single-stage Merlin XX and 45 series. A significant advance in supercharger design was the incorporation in 1938 of a two-speed drive (designed by the French company Farman ) to the impeller of
2934-415: A limiting factor in engine performance. Extreme temperatures can cause pre-ignition or knocking , which reduces performance and can cause engine damage. The risk of pre-ignition/knocking increases with higher ambient air temperatures and higher boost levels. Turbocharged engines use energy from the exhaust gas that would normally be wasted, compared with a supercharger which mechanically draws power from
3097-573: A narrow range of load/speed/boost, for which the system must be specifically designed. Positive displacement pumps deliver a nearly fixed volume of air per revolution of the compressor (except for leakage, which typically has a reduced effect at higher engine speeds). The most common type of positive-displacement superchargers is the Roots-type supercharger . Other types include the rotary-screw , sliding vane and scroll-type superchargers. The rating system for positive-displacement superchargers
3260-520: A new 1,100 hp (820 kW)-class design known as the PV-12, with PV standing for Private Venture, 12-cylinder , as the company received no government funding for work on the project. The PV-12 was first run on 15 October 1933 and first flew in a Hawker Hart biplane ( serial number K3036 ) on 21 February 1935. The engine was originally designed to use the evaporative cooling system then in vogue. This proved unreliable and when ethylene glycol from
3423-472: A nominal 150-octane rating. Using such fuels, aero engines like the Rolls-Royce Merlin 66 and Daimler-Benz DB 605 DC produced power outputs of up to 2,000 hp (1,500 kW). One disadvantage of forced induction (i.e. supercharging or turbocharging) is that compressing the intake air increases its temperature. For an internal combustion engine, the temperature of the intake air becomes
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#17327978130633586-471: A private venture. Initially known as the PV-12 , it was later called Merlin following the company convention of naming its four-stroke piston aero engines after birds of prey . The engine benefitted from the racing experiences of precursor engines in the 1930s. After several modifications, the first production variants of the PV-12 were completed in 1936. The first operational aircraft to enter service using
3749-493: A problem after some months due to the physical and mental effects of wartime conditions such as the frequent occupation of air-raid shelters . It was agreed to cut the punishing working hours slightly to 82 hours a week, with one half-Sunday per month awarded as holiday. Record production is reported to have been 100 engines in one day. Immediately after the war the site repaired and overhauled Merlin and Griffon engines, and continued to manufacture spare parts. Finally, following
3912-408: A problem would occur as the compression ratio increased as the fuel was igniting due to the rise in temperature that resulted. Charles Kettering developed a lead additive which allowed higher compression ratios, which was progressively abandoned for automotive use from the 1970s onward, partly due to lead poisoning concerns. The fuel mixture is ignited at different progressions of the piston in
4075-731: A reciprocating internal combustion engine is the engine block , which is typically made of cast iron (due to its good wear resistance and low cost) or aluminum . In the latter case, the cylinder liners are made of cast iron or steel, or a coating such as nikasil or alusil . The engine block contains the cylinders . In engines with more than one cylinder they are usually arranged either in 1 row ( straight engine ) or 2 rows ( boxer engine or V engine ); 3 or 4 rows are occasionally used ( W engine ) in contemporary engines, and other engine configurations are possible and have been used. Single-cylinder engines (or thumpers ) are common for motorcycles and other small engines found in light machinery. On
4238-422: A separate ICE as an auxiliary power unit . Wankel engines are fitted to many unmanned aerial vehicles . ICEs drive large electric generators that power electrical grids. They are found in the form of combustion turbines with a typical electrical output in the range of some 100 MW. Combined cycle power plants use the high temperature exhaust to boil and superheat water steam to run a steam turbine . Thus,
4401-423: A separate blower avoids many of the shortcomings of crankcase scavenging, at the expense of increased complexity which means a higher cost and an increase in maintenance requirement. An engine of this type uses ports or valves for intake and valves for exhaust, except opposed piston engines , which may also use ports for exhaust. The blower is usually of the Roots-type but other types have been used too. This design
4564-416: A separate crankcase ventilation system. The cylinder head is attached to the engine block by numerous bolts or studs . It has several functions. The cylinder head seals the cylinders on the side opposite to the pistons; it contains short ducts (the ports ) for intake and exhaust and the associated intake valves that open to let the cylinder be filled with fresh air and exhaust valves that open to allow
4727-505: A total displacement of 426 cu in (7.0 L)). However, because 6–71 is the engine's designation rather than that of the blower, the actual displacement of the blower is less; for example, a 6–71 blower pumps 339 cu in (5.6 L) per revolution. Other supercharger manufacturers have produced blowers rated up to 16–71. Dynamic compressors rely on accelerating the air to high speed and then exchanging that velocity for pressure by diffusing or slowing it down. Major types of
4890-476: A two-stage inter-cooled supercharger with a more compact layout. Nonetheless, turbochargers were useful in high-altitude bombers and some fighter aircraft due to the increased high altitude performance and range. Turbocharged piston engines are also subject to many of the same operating restrictions as those of gas turbine engines. Turbocharged engines also require frequent inspections of their turbochargers and exhaust systems to search for possible damage caused by
5053-481: Is intermittent , such as the more familiar two-stroke and four-stroke piston engines, along with variants, such as the six-stroke piston engine and the Wankel rotary engine . A second class of internal combustion engines use continuous combustion: gas turbines , jet engines and most rocket engines , each of which are internal combustion engines on the same principle as previously described. ( Firearms are also
Supercharger - Misplaced Pages Continue
5216-405: Is a fly-back system, using interruption of electrical primary system current through some type of synchronized interrupter. The interrupter can be either contact points or a power transistor. The problem with this type of ignition is that as RPM increases the availability of electrical energy decreases. This is especially a problem, since the amount of energy needed to ignite a more dense fuel mixture
5379-421: Is also why diesel and HCCI engines are more susceptible to cold-starting issues, although they run just as well in cold weather once started. Light duty diesel engines with indirect injection in automobiles and light trucks employ glowplugs (or other pre-heating: see Cummins ISB#6BT ) that pre-heat the combustion chamber just before starting to reduce no-start conditions in cold weather. Most diesels also have
5542-503: Is commonplace in CI engines, and has been occasionally used in SI engines. CI engines that use a blower typically use uniflow scavenging . In this design the cylinder wall contains several intake ports placed uniformly spaced along the circumference just above the position that the piston crown reaches when at BDC. An exhaust valve or several like that of 4-stroke engines is used. The final part of
5705-542: Is driven downward with power, it first uncovers the exhaust port where the burned fuel is expelled under high pressure and then the intake port where the process has been completed and will keep repeating. Later engines used a type of porting devised by the Deutz company to improve performance. It was called the Schnurle Reverse Flow system. DKW licensed this design for all their motorcycles. Their DKW RT 125
5868-415: Is held in place relative to the engine block by main bearings , which allow it to rotate. Bulkheads in the crankcase form a half of every main bearing; the other half is a detachable cap. In some cases a single main bearing deck is used rather than several smaller caps. A connecting rod is connected to offset sections of the crankshaft (the crankpins ) in one end and to the piston in the other end through
6031-406: Is higher. The result was often a high RPM misfire. Capacitor discharge ignition was developed. It produces a rising voltage that is sent to the spark plug. CD system voltages can reach 60,000 volts. CD ignitions use step-up transformers . The step-up transformer uses energy stored in a capacitance to generate electric spark . With either system, a mechanical or electrical control system provides
6194-445: Is less commonly used in the 21st century, as manufacturers have shifted to turbochargers to reduce fuel consumption and increase power outputs. There are two main families of superchargers defined according to the method of gas transfer: positive displacement and dynamic superchargers. Positive displacement superchargers deliver an almost constant level of boost pressure increase at all engine speeds, while dynamic superchargers cause
6357-445: Is not possible to dedicate a stroke exclusively for each of them. Starting at TDC the cycle consists of: While a 4-stroke engine uses the piston as a positive displacement pump to accomplish scavenging taking 2 of the 4 strokes, a 2-stroke engine uses the last part of the power stroke and the first part of the compression stroke for combined intake and exhaust. The work required to displace the charge and exhaust gases comes from either
6520-495: Is not the case because the output of the engine depends solely on the mass of air it can be made to consume efficiently, and in this respect the supercharger plays the most important role ... the engine has to be capable of dealing with the greater mass flows with respect to cooling, freedom from detonation and capable of withstanding high gas and inertia loads ... During the course of research and development on superchargers it became apparent to us that any further increase in
6683-430: Is that the intake air is warmer than at high altitude. Warmer air reduces the threshold at which engine knocking can occur, especially in supercharged or turbocharged engines. Methods to cool the intake air at ground level include intercoolers/aftercoolers , anti-detonant injection , two-speed superchargers and two-stage superchargers. In supercharged engines which use a carburetor , a partially-open throttle reduces
Supercharger - Misplaced Pages Continue
6846-514: Is the Wärtsilä-Sulzer RTA96-C turbocharged 2-stroke diesel, used in large container ships. It is the most efficient and powerful reciprocating internal combustion engine in the world with a thermal efficiency over 50%. For comparison, the most efficient small four-stroke engines are around 43% thermally-efficient (SAE 900648); size is an advantage for efficiency due to the increase in the ratio of volume to surface area. See
7009-417: Is too large for the engine displacement. For this reason, supercharged engines are common in applications where throttle response is a key concern, such as drag racing and tractor pulling competitions. A disadvantage of supercharging is that the engine must withstand the net power output of the engine plus the power to drive the supercharger. Additionally, turbochargers provide sound-dampening properties to
7172-557: Is usually based on their capacity per revolution . In the case of the Roots blower, the GMC rating pattern is typical. The GMC rating is based on how many two-stroke cylinders - and the size of those cylinders - that it is designed to scavenge , with GMC's model range including 2–71, 3–71, 4–71 and 6–71 blowers. The 6–71 blower, for example, is designed to scavenge six cylinders of 71 cu in (1.2 L) each, resulting in an engine with
7335-677: The Air Ministry had provided a total of £1,927,000 by December 1939. Having a workforce that consisted mainly of design engineers and highly skilled men, the Derby factory carried out the majority of development work on the Merlin, with flight testing carried out at nearby RAF Hucknall . All the Merlin-engined aircraft taking part in the Battle of Britain had their engines assembled in the Derby factory. Total Merlin production at Derby
7498-457: The Air Ministry , the Ministry of Aircraft Production and local authority officials. Hives was an advocate of shadow factories , and, sensing the imminent outbreak of war, pressed ahead with plans to produce the Merlin in sufficient numbers for the rapidly expanding Royal Air Force. Despite the importance of uninterrupted production, several factories were affected by industrial action . By
7661-473: The Battle of Britain Memorial Flight , and power many restored aircraft in private ownership worldwide. In the early 1930s, Rolls-Royce started planning its future aero-engine development programme and realised there was a need for an engine larger than their 21-litre (1,296 cu in) Kestrel , which was being used with great success in a number of 1930s aircraft. Consequently, work was started on
7824-602: The Lockheed Constellation , and the C-124 Globemaster II . In the 1985 and 1986 World Rally Championships, Lancia ran the Delta S4 , which incorporated both a belt-driven supercharger and exhaust-driven turbocharger. The design used a complex series of bypass valves in the induction and exhaust systems as well as an electromagnetic clutch so that, at low engine speeds, a boost was derived from
7987-618: The Pyréolophore , which was granted a patent by Napoleon Bonaparte . This engine powered a boat on the Saône river in France. In the same year, Swiss engineer François Isaac de Rivaz invented a hydrogen-based internal combustion engine and powered the engine by electric spark. In 1808, De Rivaz fitted his invention to a primitive working vehicle – "the world's first internal combustion powered automobile". In 1823, Samuel Brown patented
8150-610: The Second Tactical Air Force (2TAF) also began using 100/150 grade fuel. This fuel was also offered to the USAAF where it was designated "PPF 44-1" and informally known as "Pep". Production of the Rolls-Royce Merlin was driven by the forethought and determination of Ernest Hives , who at times was enraged by the apparent complacency and lack of urgency encountered in his frequent correspondence with
8313-601: The Supermarine Spitfire and the Hawker Hurricane ; the latter designed in response to another specification, F36/34. Both were designed around the PV-12 instead of the Kestrel, and were the only contemporary British fighters to have been so developed. Production contracts for both aircraft were placed in 1936, and development of the PV-12 was given top priority as well as government funding. Following
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#17327978130638476-473: The external links for an in-cylinder combustion video in a 2-stroke, optically accessible motorcycle engine. Dugald Clerk developed the first two-cycle engine in 1879. It used a separate cylinder which functioned as a pump in order to transfer the fuel mixture to the cylinder. In 1899 John Day simplified Clerk's design into the type of 2 cycle engine that is very widely used today. Day cycle engines are crankcase scavenged and port timed. The crankcase and
8639-528: The gas turbine and a pre-turbine section of the exhaust system. The size of the ducting alone was a serious design consideration. For example, both the F4U Corsair and the P-47 Thunderbolt used the same radial engine , but the large barrel-shaped fuselage of the turbocharged P-47 was needed because of the amount of ducting to and from the turbocharger in the rear of the aircraft. The F4U used
8802-503: The time between overhauls (TBO) was typically 650–800 hours depending on use. By then single-stage engines had accumulated 2,615,000 engine hours in civil operation, and two-stage engines 1,169,000. In addition, an exhaust system to reduce noise levels to below those from ejector exhausts was devised for the North Star/Argonaut. This "cross-over" system took the exhaust flow from the inboard bank of cylinders up-and-over
8965-432: The two-stroke oil in the air-fuel-oil mixture which is then burned along with the fuel. The valve train may be contained in a compartment flooded with lubricant so that no oil pump is required. Rolls-Royce Merlin#Improved fuels The Rolls-Royce Merlin is a British liquid-cooled V-12 piston aero engine of 27-litre (1,650 cu in) capacity . Rolls-Royce designed the engine and first ran it in 1933 as
9128-526: The 1,700 hp (1,300 kW) 42-litre (2,560 cu in) Rolls-Royce Vulture used four Kestrel-sized cylinder blocks fitted to a single crankcase and driving a common crankshaft, forming an X-24 layout. This was to be used in larger aircraft such as the Avro Manchester . Although the Peregrine appeared to be a satisfactory design, it was never allowed to mature since Rolls-Royce's priority
9291-416: The 1.6 litre Mercedes 6/25 hp and 2.6 litre Mercedes 10/40 hp , both of which began production in 1923. They were marketed as Kompressor models, a term which was used for various models until 2012. Supercharged racing cars from around this time included the 1923 Fiat 805-405 , the 1923 Miller 122 the 1924 Alfa Romeo P2 , the 1924 Grand Prix season car from Sunbeam, the 1925 Delage , and
9454-638: The 1926 Bugatti Type 35C . Amongst the most famous supercharged cars is the Bentley 4½ Litre ("Blower Bentley"), which was introduced in 1929. In 1935, the development of screw-type superchargers reached a milestone when Swedish engineer Alf Lysholm patented a design for a rotary-screw compressor with five female and four male rotors. In the 21st century, supercharged production car engines have become less common, as manufacturers have shifted to turbocharging to achieve higher fuel economy and power outputs. For example, Mercedes-Benz's Kompressor engines of
9617-569: The Bentley marque and the factory. Today it is known as Bentley Crewe. Hives further recommended that a factory be built near Glasgow to take advantage of the abundant local work force and the supply of steel and forgings from Scottish manufacturers. In September 1939, the Air Ministry allocated £4,500,000 for a new Shadow factory. This government -funded and -operated factory was built at Hillington starting in June 1939 with workers moving into
9780-469: The German engines being significantly larger in displacement. Two-stage superchargers were also always two-speed. After the air was compressed in the low-pressure stage , the air flowed through a heat exchanger (" intercooler ") where it was cooled before being compressed again by the high-pressure stage and then possibly also aftercooled in another heat exchanger. While superchargers were highly used in
9943-421: The Merlin 130/131 versions specifically designed for the de Havilland Hornet . Ultimately, during tests conducted by Rolls-Royce at Derby , an RM.17.SM (the high altitude version of the Merlin 100-Series) achieved 2,640 hp (1,970 kW) at 36 lb boost (103"Hg) on 150-octane fuel with water injection. With the end of the war, work on improving Merlin power output was halted and the development effort
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#173279781306310106-462: The Merlin 60 series gained 300 hp (220 kW) at 30,000 ft (9,100 m) over the Merlin 45 series, at which altitude a Spitfire IX was nearly 70 mph (110 km/h) faster than a Spitfire V. The two-stage Merlin family was extended in 1943 with the Merlin 66, which had its supercharger geared for increased power ratings at low altitudes, and the Merlin 70 series that were designed to deliver increased power at high altitudes. While
10269-476: The Merlin 66-powered Spitfire IXs of two Air Defence of Great Britain (ADGB) squadrons were cleared to use the new fuel for operational trials, and it was put to good use in the summer of 1944 when it enabled Spitfire L.F. Mk. IXs to intercept V-1 flying bombs coming in at low altitudes. 100/150 grade fuel was also used by Mosquito night fighters of the ADGB to intercept V-1s. In early February 1945, Spitfires of
10432-408: The Merlin X. The later Merlin XX incorporated the two-speed drive as well as several improvements that enabled the production rate of Merlins to be increased. The low-ratio gear, which operated from takeoff to an altitude of 10,000 ft (3,000 m), drove the impeller at 21,597 rpm and developed 1,240 hp (920 kW) at that height; while the high gear's (25,148 rpm) power rating
10595-553: The Merlin ran only on 100-octane fuel, and the five-minute combat limitation was raised to +18 pounds per square inch (224 kPa; 2.3 atm). In late 1943 trials were run of a new "100/150" grade (150-octane) fuel, recognised by its bright-green colour and "awful smell". Initial tests were conducted using 6.5 cubic centimetres (0.23 imp fl oz ) of tetraethyllead (T.E.L.) for every one imperial gallon of 100-octane fuel (or 1.43 cc/L or 0.18 U.S. fl oz/U.S. gal), but this mixture resulted in
10758-526: The Merlin were the Fairey Battle , Hawker Hurricane and Supermarine Spitfire . The Merlin remains most closely associated with the Spitfire and Hurricane, although the majority of the production run was for the four-engined Avro Lancaster heavy bomber. The Merlin continued to benefit from a series of rapidly-applied developments, derived from experiences in use since 1936. These markedly improved
10921-521: The Merlin's components itself. Hillingdon required "a great deal of attention from Hives" from when it was producing its first complete engine; it had the highest proportion of unskilled workers in any Rolls-Royce-managed factory”. Engines began to leave the production line in November 1940, and by June 1941 monthly output had reached 200, increasing to more than 400 per month by March 1942. In total 23,675 engines were produced. Worker absenteeism became
11084-425: The Merlin's technical improvements resulted from more efficient superchargers , designed by Stanley Hooker , and the introduction of aviation fuel with increased octane ratings . Numerous detail changes were made internally and externally to the engine to withstand increased power ratings and to incorporate advances in engineering practices. The Merlin consumed an enormous volume of air at full power (equivalent to
11247-402: The Peregrine and Vulture were both cancelled in 1943, and by mid-1943 the Merlin was supplemented in service by the larger Griffon . The Griffon incorporated several design improvements and ultimately superseded the Merlin. Initially the new engine was plagued with problems such as failure of the accessory gear trains and coolant jackets. Several different construction methods were tried before
11410-565: The Spitfire and Hurricane planes powered by the Rolls-Royce Merlin engine were equipped largely with single-stage and single-speed superchargers. In 1942, two-speed two-stage supercharging with aftercooling was applied to the Rolls Royce Merlin 61 aero engine. The improved performance allowed the aircraft they powered to maintain a crucial advantage over the German aircraft they opposed throughout World War II, despite
11573-520: The Spitfire used a variation of this exhaust system fitted with forward-facing intake ducts to distribute hot air out to the wing-mounted guns to prevent freezing and stoppages at high altitudes, replacing an earlier system that used heated air from the engine coolant radiator. The latter system had become ineffective due to improvements to the Merlin itself which allowed higher operating altitudes where air temperatures are lower . Ejector exhausts were also fitted to other Merlin-powered aircraft. Central to
11736-444: The U.S. became available, the engine was adapted to use a conventional liquid-cooling system. The Hart was subsequently delivered to Rolls-Royce where, as a Merlin testbed , it completed over 100 hours of flying with the Merlin C and E engines. In 1935, the Air Ministry issued a specification, F10/35 , for new fighter aircraft with a minimum airspeed of 310 mph (500 km/h ). Fortunately, two designs had been developed:
11899-498: The United States patented the design for an air mover for use in blast furnaces and other industrial applications. This air mover and Birmingham's ventilation compressor both used designs similar to that of the later Roots-type superchargers . In March of 1878, German engineer Heinrich Krigar obtained the first patent for a screw-type compressor. The design was a two-lobe rotor assembly with identically-shaped rotors, however
12062-619: The Wankel design are used in some automobiles, aircraft and motorcycles. These are collectively known as internal-combustion-engine vehicles (ICEV). Where high power-to-weight ratios are required, internal combustion engines appear in the form of combustion turbines , or sometimes Wankel engines. Powered aircraft typically use an ICE which may be a reciprocating engine. Airplanes can instead use jet engines and helicopters can instead employ turboshafts ; both of which are types of turbines. In addition to providing propulsion, aircraft may employ
12225-402: The air density at 30,000 ft (9,100 m) is 1 ⁄ 3 of that at sea level, resulting in 1 ⁄ 3 as much fuel being able to be burnt in a naturally aspirated engine, therefore the power output would be greatly reduced. A supercharger/turbocharger can be thought of either as artificially increasing the density of the air by compressing it or as forcing more air than normal into
12388-433: The air pressure within the carburetor. In cold conditions, this low pressure air can cause ice to form at the throttle plate. Significant quantities of ice can cause engine failure, even with the engine operating at full rated power. Internal combustion engine An internal combustion engine ( ICE or IC engine ) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in
12551-477: The altitude performance of the Merlin engine necessitated the employment of a two-stage supercharger. As the Merlin evolved so too did the supercharger; the latter fitting into three broad categories: The Merlin supercharger was originally designed to allow the engine to generate maximum power at an altitude of about 16,000 ft (4,900 m). In 1938 Stanley Hooker, an Oxford graduate in applied mathematics, explained "... I soon became very familiar with
12714-489: The associated process. While an engine is in operation, the crankshaft rotates continuously at a nearly constant speed . In a 4-stroke ICE, each piston experiences 2 strokes per crankshaft revolution in the following order. Starting the description at TDC, these are: The defining characteristic of this kind of engine is that each piston completes a cycle every crankshaft revolution. The 4 processes of intake, compression, power and exhaust take place in only 2 strokes so that it
12877-478: The basic design of the Merlin was set. Early production Merlins were unreliable: common problems were cylinder head cracking, coolant leaks, and excessive wear to the camshafts and crankshaft main bearings . The prototype, developmental, and early production engine types were the: The Merlin II and III series were the first main production versions of the engine. The Merlin III was the first version to incorporate
13040-649: The benefit to the operational range was given a much higher priority to American aircraft because of a less predictable requirement on the operational range and having to travel far from their home bases. Consequently, turbochargers were mainly employed in American aircraft engines such as the Allison V-1710 and the Pratt & Whitney R-2800 , which were comparably heavier when turbocharged, and required additional ducting of expensive high-temperature metal alloys in
13203-431: The boost pressure to rise exponentially with engine speed (above a certain threshold). Another family of supercharger, albeit rarely used, is the pressure wave supercharger . Roots blowers (a positive displacement design) tend to be only 40–50% efficient at high boost levels, compared with 70-85% for dynamic superchargers. Lysholm-style blowers (a rotary-screw design) can be nearly as efficient as dynamic superchargers over
13366-619: The combustion gases to escape. The valves are often poppet valves but they can also be rotary valves or sleeve valves . However, 2-stroke crankcase scavenged engines connect the gas ports directly to the cylinder wall without poppet valves; the piston controls their opening and occlusion instead. The cylinder head also holds the spark plug in the case of spark ignition engines and the injector for engines that use direct injection. All CI (compression ignition) engines use fuel injection, usually direct injection but some engines instead use indirect injection . SI (spark ignition) engines can use
13529-470: The company convention of naming its piston aero engines after birds of prey, Rolls-Royce named the engine the Merlin after a small, Northern Hemisphere falcon ( Falco columbarius ). Two more Rolls-Royce engines developed just prior to the war were added to the company's range. The 885 hp (660 kW) Rolls-Royce Peregrine was an updated, supercharged development of their V-12 Kestrel design, while
13692-533: The component over a distance. This process transforms chemical energy into kinetic energy which is used to propel, move or power whatever the engine is attached to. The first commercially successful internal combustion engine was created by Étienne Lenoir around 1860, and the first modern internal combustion engine, known as the Otto engine , was created in 1876 by Nicolaus Otto . The term internal combustion engine usually refers to an engine in which combustion
13855-455: The compressed air and combustion products and slide continuously within it while the engine is in operation. In smaller engines, the pistons are made of aluminum; while in larger applications, they are typically made of cast iron. In performance applications, pistons can also be titanium or forged steel for greater strength. The top surface of the piston is called its crown and is typically flat or concave. Some two-stroke engines use pistons with
14018-432: The compressed charge, four-cycle engine. In 1879, Karl Benz patented a reliable two-stroke gasoline engine. Later, in 1886, Benz began the first commercial production of motor vehicles with an internal combustion engine, in which a three-wheeled, four-cycle engine and chassis formed a single unit. In 1892, Rudolf Diesel developed the first compressed charge, compression ignition engine. In 1926, Robert Goddard launched
14181-488: The construction of the Merlin supercharger and carburettor ... Since the supercharger was at the rear of the engine it had come in for pretty severe design treatment, and the air intake duct to the impeller looked very squashed ..." Tests conducted by Hooker showed the original intake design was inefficient, limiting the performance of the supercharger. Hooker subsequently designed a new air intake duct with improved flow characteristics, which increased maximum power at
14344-410: The corresponding ports. The intake manifold connects to the air filter directly, or to a carburetor when one is present, which is then connected to the air filter . It distributes the air incoming from these devices to the individual cylinders. The exhaust manifold is the first component in the exhaust system . It collects the exhaust gases from the cylinders and drives it to the following component in
14507-400: The crankcase or a separate blower. For scavenging, expulsion of burned gas and entry of fresh mix, two main approaches are described: Loop scavenging, and Uniflow scavenging. SAE news published in the 2010s that 'Loop Scavenging' is better under any circumstance than Uniflow Scavenging. Some SI engines are crankcase scavenged and do not use poppet valves. Instead, the crankcase and the part of
14670-401: The crankcase pressure is slightly below intake pressure, to let it be filled with a new charge; this happens when the piston is moving upwards. When the piston is moving downwards the pressure in the crankcase increases and the reed valve closes promptly, then the charge in the crankcase is compressed. When the piston is moving downwards, it also uncovers the exhaust port and the transfer port and
14833-413: The crankcase to the port in the cylinder to provide for intake and another from the exhaust port to the exhaust pipe. The height of the port in relationship to the length of the cylinder is called the "port timing". On the first upstroke of the engine there would be no fuel inducted into the cylinder as the crankcase was empty. On the downstroke, the piston now compresses the fuel mix, which has lubricated
14996-431: The cylinder below the piston is used as a pump. The intake port is connected to the crankcase through a reed valve or a rotary disk valve driven by the engine. For each cylinder, a transfer port connects in one end to the crankcase and in the other end to the cylinder wall. The exhaust port is connected directly to the cylinder wall. The transfer and exhaust port are opened and closed by the piston. The reed valve opens when
15159-411: The cylinder block has fins protruding away from it to cool the engine by directly transferring heat to the air. The cylinder walls are usually finished by honing to obtain a cross hatch , which is able to retain more oil. A too rough surface would quickly harm the engine by excessive wear on the piston. The pistons are short cylindrical parts which seal one end of the cylinder from the high pressure of
15322-409: The cylinder every time the piston moves down on the intake stroke. Since a supercharger is usually designed to produce a given amount of boost at high altitudes (where the air density is lower), the supercharger is often oversized for low altitude. To prevent excessive boost levels, it is important to monitor the intake manifold pressure at low altitude. As the aircraft climbs and the air density drops,
15485-407: The cylinder. Because there is no obstruction in the cylinder of the fuel to move directly out of the exhaust port prior to the piston rising far enough to close the port, early engines used a high domed piston to slow down the flow of fuel. Later the fuel was "resonated" back into the cylinder using an expansion chamber design. When the piston rose close to TDC, a spark ignited the fuel. As the piston
15648-414: The cylinder. At low rpm, the spark is timed to occur close to the piston achieving top dead center. In order to produce more power, as rpm rises the spark is advanced sooner during piston movement. The spark occurs while the fuel is still being compressed progressively more as rpm rises. The necessary high voltage, typically 10,000 volts, is supplied by an induction coil or transformer. The induction coil
15811-444: The design did not reach production. Also in 1878, Scottish engineer Dugald Clerk designed the first supercharger which was used with an engine. This supercharger was used with a two-stroke gas engine. Gottlieb Daimler received a German patent for supercharging an internal combustion engine in 1885. Louis Renault patented a centrifugal supercharger in France in 1902. The world's first series-produced cars with superchargers were
15974-483: The design of the two-stage supercharger forged ahead, Rolls-Royce also continued to develop the single-stage supercharger, resulting in 1942 in the development of a smaller "cropped" impeller for the Merlin 45M and 55M; both of these engines developed greater power at low altitudes. In squadron service the LF.V variant of the Spitfire fitted with these engines became known as the "clipped, clapped, and cropped Spitty" to indicate
16137-780: The early 2000s (such as the C 230 Kompressor straight-four, C 32 AMG V6, and CL 55 AMG V8 engines) were replaced around 2010 by turbocharged engines in models such as the C 250 and CL 65 AMG models. However, there are exceptions, such as the Audi 3.0 TFSI supercharged V6 (introduced in 2009) and the Jaguar AJ-V8 supercharged V8 (upgraded to the Gen III version in 2009). In the 1930s, two-speed drives were developed for superchargers for aero engines providing more flexible aircraft operation. The arrangement also entailed more complexity of manufacturing and maintenance. The gears connected
16300-413: The early engines which used Hot Tube ignition. When Bosch developed the magneto it became the primary system for producing electricity to energize a spark plug. Many small engines still use magneto ignition. Small engines are started by hand cranking using a recoil starter or hand crank. Prior to Charles F. Kettering of Delco's development of the automotive starter all gasoline engined automobiles used
16463-453: The efficiency is higher because more energy is extracted from the fuel than what could be extracted by the combustion engine alone. Combined cycle power plants achieve efficiencies in the range of 50–60%. In a smaller scale, stationary engines like gas engines or diesel generators are used for backup or for providing electrical power to areas not connected to an electric grid . Small engines (usually 2‐stroke gasoline/petrol engines) are
16626-538: The end of its production run in 1950, 168,176 Merlin engines had been built; over 112,000 in Britain and more than 55,000 under licence in the U.S. The existing Rolls-Royce facilities at Osmaston, Derby were not suitable for mass engine production although the floor space had been increased by some 25% between 1935 and 1939; Hives planned to build the first two or three hundred engines there until engineering teething troubles had been resolved. To fund this expansion,
16789-472: The engine before discharging the exhaust stream on the outboard side of the UPP nacelle. As a result, sound levels were reduced by between 5 and 8 decibels . The modified exhaust also conferred an increase in horsepower over the unmodified system of 38 hp (28 kW), resulting in a 5 knot improvement in true air speed. Still-air range of the aircraft was also improved by around 4 per cent. The modified engine
16952-543: The engine is off. The battery also supplies electrical power during rare run conditions where the alternator cannot maintain more than 13.8 volts (for a common 12 V automotive electrical system). As alternator voltage falls below 13.8 volts, the lead-acid storage battery increasingly picks up electrical load. During virtually all running conditions, including normal idle conditions, the alternator supplies primary electrical power. Some systems disable alternator field (rotor) power during wide-open throttle conditions. Disabling
17115-676: The engine's performance and durability. Starting at 1,000 horsepower (750 kW) for the first production models, most late war versions produced just under 1,800 horsepower (1,300 kW), and the very latest version as used in the de Havilland Hornet over 2,000 horsepower (1,500 kW). One of the most successful aircraft engines of the World War II era, some 50 versions of the Merlin were built by Rolls-Royce in Derby , Crewe and Glasgow , as well as by Ford of Britain at their Trafford Park factory , near Manchester . A de-rated version
17278-412: The engine. Therefore turbocharged engines usually produce more power and better fuel economy than supercharged engines. However, turbochargers can suffer from turbo lag (especially at lower RPM), where the exhaust gas flow is initially insufficient to spin the turbocharger and achieve the desired boost level, thus leading to a delay in the throttle response . This is often a result of a turbo charge which
17441-441: The exhaust gases. However, up until the mid-20th century, a turbocharger was called a "turbosupercharger" and was considered a type of supercharger. The first supercharged engine was built in 1878, with usage in aircraft engines beginning in the 1910s and usage in car engines beginning in the 1920s. In piston engines used by aircraft, supercharging was often used to compensate for the lower air density at high altitudes. Supercharging
17604-768: The extreme heat and pressure of the turbochargers. Such damage was a prominent problem in the early models of the American Boeing B-29 Superfortress high-altitude bombers used in the Pacific Theater of Operations during 1944–45. Turbocharged piston engines continued to be used in a large number of postwar airplanes, such as the B-50 Superfortress , the KC-97 Stratofreighter , the Boeing 377 Stratocruiser ,
17767-435: The field reduces alternator pulley mechanical loading to nearly zero, maximizing crankshaft power. In this case, the battery supplies all primary electrical power. Gasoline engines take in a mixture of air and gasoline and compress it by the movement of the piston from bottom dead center to top dead center when the fuel is at maximum compression. The reduction in the size of the swept area of the cylinder and taking into account
17930-671: The first internal combustion engine to be applied industrially. In 1854, in the UK, the Italian inventors Eugenio Barsanti and Felice Matteucci obtained the certification: "Obtaining Motive Power by the Explosion of Gases". In 1857 the Great Seal Patent Office conceded them patent No.1655 for the invention of an "Improved Apparatus for Obtaining Motive Power from Gases". Barsanti and Matteucci obtained other patents for
18093-595: The first liquid-fueled rocket. In 1939, the Heinkel He 178 became the world's first jet aircraft . At one time, the word engine (via Old French , from Latin ingenium , "ability") meant any piece of machinery —a sense that persists in expressions such as siege engine . A "motor" (from Latin motor , "mover") is any machine that produces mechanical power . Traditionally, electric motors are not referred to as "engines"; however, combustion engines are often referred to as "motors". (An electric engine refers to
18256-604: The following conditions: The main advantage of 2-stroke engines of this type is mechanical simplicity and a higher power-to-weight ratio than their 4-stroke counterparts. Despite having twice as many power strokes per cycle, less than twice the power of a comparable 4-stroke engine is attainable in practice. In the US, 2-stroke engines were banned for road vehicles due to the pollution. Off-road only motorcycles are still often 2-stroke but are rarely road legal. However, many thousands of 2-stroke lawn maintenance engines are in use. Using
18419-428: The fuel supply line together with a diaphragm fitted in the float chamber, jocularly nicknamed " Miss Shilling's orifice ", after its inventor, went some way towards curing fuel starvation in a dive by containing fuel under negative G; however, at less than maximum power a fuel-rich mixture still resulted. Another improvement was made by moving the fuel outlet from the bottom of the S.U. carburettor to exactly halfway up
18582-537: The great Ford factory at Manchester started production, Merlins came out like shelling peas ...". Some 17,316 people worked at the Trafford Park plant, including 7,260 women and two resident doctors and nurses. Merlin production started to run down in August 1945, and finally ceased on 23 March 1946. Total Merlin production at Trafford Park was 30,428. As the Merlin was considered to be so important to
18745-517: The gudgeon pin and thus transfers the force and translates the reciprocating motion of the pistons to the circular motion of the crankshaft. The end of the connecting rod attached to the gudgeon pin is called its small end, and the other end, where it is connected to the crankshaft, the big end. The big end has a detachable half to allow assembly around the crankshaft. It is kept together to the connecting rod by removable bolts. The cylinder head has an intake manifold and an exhaust manifold attached to
18908-505: The high temperature and pressure created by the engine in its compression process. The compression level that occurs is usually twice or more than a gasoline engine. Diesel engines take in air only, and shortly before peak compression, spray a small quantity of diesel fuel into the cylinder via a fuel injector that allows the fuel to instantly ignite. HCCI type engines take in both air and fuel, but continue to rely on an unaided auto-combustion process, due to higher pressures and temperature. This
19071-416: The higher pressure of the charge in the crankcase makes it enter the cylinder through the transfer port, blowing the exhaust gases. Lubrication is accomplished by adding two-stroke oil to the fuel in small ratios. Petroil refers to the mix of gasoline with the aforesaid oil. This kind of 2-stroke engine has a lower efficiency than comparable 4-strokes engines and releases more polluting exhaust gases for
19234-451: The highest thermal efficiencies among internal combustion engines of any kind. Some diesel–electric locomotive engines operate on the 2-stroke cycle. The most powerful of them have a brake power of around 4.5 MW or 6,000 HP . The EMD SD90MAC class of locomotives are an example of such. The comparable class GE AC6000CW , whose prime mover has almost the same brake power, uses a 4-stroke engine. An example of this type of engine
19397-419: The intake manifold is an air sleeve that feeds the intake ports. The intake ports are placed at a horizontal angle to the cylinder wall (I.e: they are in plane of the piston crown) to give a swirl to the incoming charge to improve combustion. The largest reciprocating IC are low speed CI engines of this type; they are used for marine propulsion (see marine diesel engine ) or electric power generation and achieve
19560-429: The inventor of the diesel engine, Rudolf Diesel , was using peanut oil to run his engines. Renewable fuels are commonly blended with fossil fuels. Hydrogen , which is rarely used, can be obtained from either fossil fuels or renewable energy. Various scientists and engineers contributed to the development of internal combustion engines. In 1791, John Barber developed the gas turbine . In 1794 Thomas Mead patented
19723-428: The level maximum speed of the Spitfire by 10 mph (16 km/h) to 360 mph (580 km/h). The first versions of the ejector exhausts featured round outlets, while subsequent versions of the system used "fishtail" style outlets, which marginally increased thrust and reduced exhaust glare for night flying. In September 1937 the Spitfire prototype, K5054 , was fitted with ejector type exhausts. Later marks of
19886-481: The maximum boost pressure at which the engine could be run using 87-octane fuel was +6 pounds per square inch (141 kPa; 1.44 atm ). However, as early as 1938, at the 16th Paris Air Show , Rolls-Royce displayed two versions of the Merlin rated to use 100-octane fuel. The Merlin R.M.2M was capable of 1,265 hp (943 kW) at 7,870 feet (2,400 m), 1,285 hp (958 kW) at 9,180 feet (2,800 m) and 1,320 hp (980 kW) on take-off; while
20049-443: The mid-1900s and during WWII , they have largely fallen out of use in modern piston-driven aircraft . This can largely be attributed to the higher temperature and lighter alloys that make turbochargers more efficient than superchargers, as well as the lower maintenance due to less moving parts. Due to the reduced air density at higher altitudes, supercharging and turbocharging have often been used in aircraft engines. For example,
20212-424: The number of required sub-contracted parts such as crankshafts, camshafts and cylinder liners eventually fell short and the factory was expanded to manufacture these parts "in house". Initially the local authority promised to build 1,000 new houses to accommodate the workforce by the end of 1938, but by February 1939 it had only awarded a contract for 100. Hives was incensed by this complacency and threatened to move
20375-407: The oil into the combustion chamber. A ventilation system drives the small amount of gas that escapes past the pistons during normal operation (the blow-by gases) out of the crankcase so that it does not accumulate contaminating the oil and creating corrosion. In two-stroke gasoline engines the crankcase is part of the air–fuel path and due to the continuous flow of it, two-stroke engines do not need
20538-476: The oil leaks that had been a problem with the early Merlin I, II and III series. The process of improvement continued, with later versions running on higher octane ratings, delivering more power. Fundamental design changes were also made to all key components, again increasing the engine's life and reliability. By the end of the war the "little" engine was delivering over 1,600 hp (1,200 kW) in common versions, and as much as 2,030 hp (1,510 kW) in
20701-402: The outer side of the cylinder, passages that contain cooling fluid are cast into the engine block whereas, in some heavy duty engines, the passages are the types of removable cylinder sleeves which can be replaceable. Water-cooled engines contain passages in the engine block where cooling fluid circulates (the water jacket ). Some small engines are air-cooled, and instead of having a water jacket
20864-460: The part of the cylinder below the exhaust port is used as a pump. The operation of the Day cycle engine begins when the crankshaft is turned so that the piston moves from BDC upward (toward the head) creating a vacuum in the crankcase/cylinder area. The carburetor then feeds the fuel mixture into the crankcase through a reed valve or a rotary disk valve (driven by the engine). There are cast in ducts from
21027-427: The path. The exhaust system of an ICE may also include a catalytic converter and muffler . The final section in the path of the exhaust gases is the tailpipe . The top dead center (TDC) of a piston is the position where it is nearest to the valves; bottom dead center (BDC) is the opposite position where it is furthest from them. A stroke is the movement of a piston from TDC to BDC or vice versa, together with
21190-412: The piston in the cylinder and the bearings due to the fuel mix having oil added to it. As the piston moves downward it first uncovers the exhaust, but on the first stroke there is no burnt fuel to exhaust. As the piston moves downward further, it uncovers the intake port which has a duct that runs to the crankcase. Since the fuel mix in the crankcase is under pressure, the mix moves through the duct and into
21353-409: The power wasting in overcoming friction , or to make the mechanism work at all. Also, the lubricant used can reduce excess heat and provide additional cooling to components. At the very least, an engine requires lubrication in the following parts: In 2-stroke crankcase scavenged engines, the interior of the crankcase, and therefore the crankshaft, connecting rod and bottom of the pistons are sprayed by
21516-653: The premises in October, one month after the outbreak of war. The factory was fully occupied by September 1940. A housing crisis also occurred at Glasgow, where Hives again asked the Air Ministry to step in. With 16,000 employees, the Glasgow factory was one of the largest industrial operations in Scotland. Unlike the Derby and Crewe plants, which relied significantly on external subcontractors , it produced almost all
21679-403: The primary power supply for vehicles such as cars , aircraft and boats . ICEs are typically powered by hydrocarbon -based fuels like natural gas , gasoline , diesel fuel , or ethanol . Renewable fuels like biodiesel are used in compression ignition (CI) engines and bioethanol or ETBE (ethyl tert-butyl ether) produced from bioethanol in spark ignition (SI) engines. As early as 1900
21842-522: The production of the Rolls-Royce Avon turbojet and others, the factory was closed in 2005. The Ford Motor Company was asked to produce Merlins at Trafford Park , Stretford , near Manchester , and building work on a new factory was started in May 1940 on a 118-acre (48 ha) site. Built with two distinct sections to minimise potential bomb damage, it was completed in May 1941 and bombed in
22005-454: The prototype high-altitude Vickers Wellington V bomber, Rolls-Royce started experiments on the design of a two-stage supercharger and an engine fitted with this was bench-tested in April 1941, eventually becoming the Merlin 60. The basic design used a modified Vulture supercharger for the first stage while a Merlin 46 supercharger was used for the second. A liquid-cooled intercooler on top of
22168-452: The same invention in France, Belgium and Piedmont between 1857 and 1859. In 1860, Belgian engineer Jean Joseph Etienne Lenoir produced a gas-fired internal combustion engine. In 1864, Nicolaus Otto patented the first atmospheric gas engine. In 1872, American George Brayton invented the first commercial liquid-fueled internal combustion engine. In 1876, Nicolaus Otto began working with Gottlieb Daimler and Wilhelm Maybach , patented
22331-473: The same month. At first, the factory had difficulty in attracting suitable labour, and large numbers of women, youths and untrained men had to be taken on. Despite this, the first Merlin engine came off the production line one month later and it was building the engine at a rate of 200 per week by 1943, at which point the joint factories were producing 18,000 Merlins per year. In his autobiography Not much of an Engineer , Sir Stanley Hooker states: "... once
22494-475: The shortened wingspan , the less-than-perfect condition of the used airframes , and the cropped supercharger impeller. The use of carburettors was calculated to give a higher specific power output, due to the lower temperature, hence greater density, of the fuel/air mixture compared to injected systems. Initially Merlins were fitted with float controlled carburettors. However, during the Battle of Britain it
22657-437: The side, which allowed the fuel to flow equally well under negative or positive g. Further improvements were introduced throughout the Merlin range: 1943 saw the introduction of a Bendix-Stromberg pressure carburettor that injected fuel at 5 pounds per square inch (34 kPa ; 0.34 bar ) through a nozzle directly into the supercharger, and was fitted to Merlin 66, 70, 76, 77 and 85 variants. The final development, which
22820-400: The stem of the valve or may act upon a rocker arm , again, either directly or through a pushrod . The crankcase is sealed at the bottom with a sump that collects the falling oil during normal operation to be cycled again. The cavity created between the cylinder block and the sump houses a crankshaft that converts the reciprocating motion of the pistons to rotational motion. The crankshaft
22983-431: The success of the Merlin was the supercharger. A.C. Lovesey , an engineer who was a key figure in the design of the Merlin, delivered a lecture on the development of the Merlin in 1946; in this extract he explained the importance of the supercharger: The impression still prevails that the static capacity known as the swept volume is the basis of comparison of the possible power output for different types of engine, but this
23146-425: The supercharger casing was used to prevent the compressed air/fuel mixture from becoming too hot. Also considered was an exhaust-driven turbocharger , but although a lower fuel consumption was an advantage, the added weight and the need to add extra ducting for the exhaust flow and waste-gates meant that this option was rejected in favour of the two-stage supercharger. Fitted with the two-stage two-speed supercharger,
23309-400: The supercharger to the engine using a system of hydraulic clutches, which were initially manually engaged or disengaged by the pilot with a control in the cockpit. At low altitudes, the low-speed gear would be used, to prevent excessive boost levels. At higher altitudes, the supercharger could be switched to a higher gear to compensate for the reduced intake air density. In the Battle of Britain
23472-499: The supercharger. In the middle of the rev range, a boost was derived from both systems, while at the highest revs the system disconnected the drive from the supercharger and isolated the associated ducting. This was done in an attempt to exploit the advantages of each of the charging systems while removing the disadvantages. In turn, this approach brought greater complexity and affected the car's reliability in WRC events, as well as increasing
23635-457: The throttle can be progressively opened to obtain the maximum safe power level for a given altitude. The altitude at which the throttle reaches full open and the engine is still producing full rated power is known as the critical altitude . Above the critical altitude, engine power output will reduce as the supercharger can no longer fully compensate for the decreasing air density. Another issue encountered at low altitudes (such as at ground level)
23798-408: The two-speed superchargers designed by Rolls-Royce, resulting in increased power at higher altitudes than previous versions. Another improvement, introduced with the Merlin X, was the use of a 70%–30% water-glycol coolant mix rather than the 100% glycol of the earlier versions. This substantially improved engine life and reliability, removed the fire hazard of the flammable ethylene glycol , and reduced
23961-403: The volume of a single-decker bus per minute), and with the exhaust gases exiting at 1,300 mph (2,100 km/h) it was realised that useful thrust could be gained simply by angling the gases backwards instead of venting sideways. During tests, 70 pounds-force (310 N ; 32 kgf ) thrust at 300 mph (480 km/h), or roughly 70 hp (52 kW) was obtained, which increased
24124-423: The volume of the combustion chamber is described by a ratio. Early engines had compression ratios of 6 to 1. As compression ratios were increased, the efficiency of the engine increased as well. With early induction and ignition systems the compression ratios had to be kept low. With advances in fuel technology and combustion management, high-performance engines can run reliably at 12:1 ratio. With low octane fuel,
24287-595: The war effort, negotiations were started to establish an alternative production line outside the UK. Rolls-Royce staff visited North American automobile manufacturers to select one to build the Merlin in the U.S. or Canada. Henry Ford rescinded an initial offer to build the engine in the U.S. in July 1940, and the Packard Motor Car Company was selected to take on the $ 130,000,000 Merlin order (equivalent to $ 2.83 billion in 2023 dollars ). Agreement
24450-545: The weight of engine ancillaries in the finished design. Twincharged engines have occasionally been used in production cars, such as the 2005-2013 Volkswagen 1.4 litre and the 2017-present Volvo B4204T43/B4204T48 2.0 litre four-cylinder engines. In 1849, G. Jones of Birmingham, England began manufacturing a lobe pump compressor to provide ventilation for coal mines. In 1860, the Roots Blower Company (founded by brothers Philander and Francis Marion Roots) in
24613-488: The whole operation, but timely intervention by the Air Ministry improved the situation. In 1940 a strike took place when women replaced men on capstan lathes , the workers' union insisting this was a skilled labour job; however, the men returned to work after 10 days. Total Merlin production at Crewe was 26,065. The factory was used postwar for the production of Rolls-Royce and Bentley motor cars and military fighting vehicle power plants. In 1998 Volkswagen AG bought
24776-549: The world, the oil was actually drained and heated overnight and returned to the engine for cold starts. In the early 1950s, the gasoline Gasifier unit was developed, where, on cold weather starts, raw gasoline was diverted to the unit where part of the fuel was burned causing the other part to become a hot vapor sent directly to the intake valve manifold. This unit was quite popular until electric engine block heaters became standard on gasoline engines sold in cold climates. For ignition, diesel, PPC and HCCI engines rely solely on
24939-426: Was 1,175 hp (876 kW) at 18,000 ft (5,500 m). These figures were achieved at 2,850 rpm engine speed using +9 pounds per square inch (1.66 atm ) (48") boost. In 1940, after receiving a request in March of that year from the Ministry of Aircraft Production for a high-rated (40,000 ft (12,000 m)) Merlin for use as an alternative engine to the turbocharged Hercules VIII used in
25102-522: Was 32,377. The original factory closed in March 2008, but the company maintains a presence in Derby. To meet the increasing demand for Merlin engines, Rolls-Royce started building work on a new factory at Crewe in May 1938, with engines leaving the factory in 1939. The Crewe factory had convenient road and rail links to their existing facilities at Derby. Production at Crewe was originally planned to use unskilled labour and sub-contractors with which Hives felt there would be no particular difficulty, but
25265-695: Was also the basis of the Rolls-Royce/Rover Meteor tank engine. Post-war, the Merlin was largely superseded by the Rolls-Royce Griffon for military use, with most Merlin variants being designed and built for airliners and military transport aircraft . The Packard V-1650 was a version of the Merlin built in the United States. Production ceased in 1950 after a total of almost 150,000 engines had been delivered. Merlin engines remain in Royal Air Force service today with
25428-625: Was concentrated on civil derivatives of the Merlin. Development of what became the "Transport Merlin" (TML) commenced with the Merlin 102 (the first Merlin to complete the new civil type-test requirements) and was aimed at improving reliability and service overhaul periods for airline operators using airliner and transport aircraft such as the Avro Lancastrian , Avro York (Merlin 500-series), Avro Tudor II and IV (Merlin 621), Tudor IVB and V (Merlin 623), TCA Canadair North Star (Merlin 724) and BOAC Argonaut (Merlin 724-IC). By 1951
25591-988: Was designated the "TMO" and the modified exhaust system was supplied as kit that could be installed on existing engines either by the operator or by Rolls-Royce. Power ratings for the civil Merlin 600, 620, and 621-series was 1,160 hp (870 kW) continuous cruising at 23,500 feet (7,200 m), and 1,725 hp (1,286 kW) for take-off. Merlins 622–626 were rated at 1,420 hp (1,060 kW) continuous cruising at 18,700 feet (5,700 m), and 1,760 hp (1,310 kW) for take-off. Engines were available with single-stage, two-speed supercharging (500-series), two-stage, two-speed supercharging (600-series), and with full intercooling, or with half intercooling/charge heating, charge heating being employed for cold area use such as in Canada. Civil Merlin engines in airline service flew 7,818,000 air miles in 1946, 17,455,000 in 1947, and 24,850,000 miles in 1948. From Jane's : Most of
25754-409: Was fitted to the 100-series Merlins, was an S.U. injection carburettor that injected fuel into the supercharger using a fuel pump driven as a function of crankshaft speed and engine pressures. At the start of the war, the Merlin I, II and III ran on the then standard 87-octane aviation spirit and could generate just over 1,000 hp (750 kW) from its 27-litre (1,650-cu in) displacement:
25917-462: Was found that if Spitfires or Hurricanes were to pitch nose down into a steep dive, negative g -force ( g ) produced temporary fuel starvation causing the engine to cut-out momentarily. By comparison, the contemporary Bf 109E , which had direct fuel injection , could "bunt" straight into a high-power dive to escape attack. RAF fighter pilots soon learned to avoid this with a "half-roll" of their aircraft before diving in pursuit. A restrictor in
26080-430: Was no mechanical time limit mechanism, but pilots were advised not to use increased boost for more than a maximum of five minutes, and it was considered a "definite overload condition on the engine"; if the pilot resorted to emergency boost he had to report this on landing, when it was noted in the engine log book, while the engineering officer was required to examine the engine and reset the throttle gate. Later versions of
26243-405: Was one of the first motor vehicles to achieve over 100 mpg as a result. Internal combustion engines require ignition of the mixture, either by spark ignition (SI) or compression ignition (CI) . Before the invention of reliable electrical methods, hot tube and flame methods were used. Experimental engines with laser ignition have been built. The spark-ignition engine was a refinement of
26406-600: Was refining the Merlin. As a result, the Peregrine saw use in only two aircraft: the Westland Whirlwind fighter and one of the Gloster F.9/37 prototypes. The Vulture was fitted to the Avro Manchester bomber, but proved unreliable in service and the planned fighter using it – the Hawker Tornado – was cancelled as a result. With the Merlin itself soon pushing into the 1,500 hp (1,100 kW) range,
26569-503: Was used to vastly increase the power output for several speed record airplanes. Military use of high-octane fuels began in early 1940 when 100-octane fuel was delivered to the British Royal Air Force fighting in World War II. The German Luftwaffe also had supplies of a similar fuel. Increasing the octane rating became a major focus of aero engine development for the remainder of the war, with later fuels having up to
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