A rotorcraft or rotary-wing aircraft is a heavier-than-air flying machine that uses lift generated by wings, called rotary wings or rotor blades, that revolve around a mast. Several rotor blades mounted on a single mast are referred to as a rotor; the International Civil Aviation Organization defines a rotorcraft as "supported in flight by the reactions of the air on one or more rotors". Rotorcraft include those aircraft where one or more rotors are required to provide lift throughout the entire flight, such as helicopters and gyrodynes. Compound rotorcraft may include additional thrust engines or propellers and static lifting surfaces. A helicopter is a rotorcraft whose rotors are driven by the engine throughout the flight to allow the helicopter to take off vertically, fly forwards and laterally, as well as to land vertically. Helicopters have several different configurations of one or more main rotors. Helicopters with a single shaft-driven main lift rotor require some sort of antitorque device such as a tail rotor, fantail, or NOTAR, except some rare examples of helicopters using tip jet propulsion, which generates no torque.
An autogyro utilizes an unpowered rotor, driven by aerodynamic forces in a state of autorotation to develop lift, an engine-powered propeller, similar to that of a fixed-wing aircraft, to provide thrust. While similar to a helicopter rotor in appearance, the autogyro's rotor must have air flowing up and through the rotor disk in order to generate rotation. Early autogyros resembled the fixed-wing aircraft of the day, with wings and a front-mounted engine and propeller in a tractor configuration to pull the aircraft through the air. Late-model autogyros feature a rear-mounted propeller in a pusher configuration; the autogyro was invented in 1920 by Juan de la Cierva. The autogyro with pusher propeller was first tested by Etienne Dormoy with his Buhl A-1 Autogyro; the rotor of a gyrodyne is driven by its engine for takeoff and landing – hovering like a helicopter – with anti-torque and propulsion for forward flight provided by one or more propellers mounted on short or stub wings. As power is increased to the propeller, less power is required by the rotor to provide forward thrust resulting in reduced pitch angles and rotor blade flapping.
At cruise speeds with most or all of the thrust being provided by the propellers, the rotor receives power only sufficient to overcome the profile drag and maintain lift. The effect is a rotorcraft operating in a more efficient manner than the freewheeling rotor of an autogyro in autorotation, minimizing the adverse effects of retreating blade stall of helicopters at higher airspeeds. A rotor kite or gyroglider is an unpowered rotary-wing aircraft. Like an autogyro or helicopter, it relies on lift created by one or more sets of rotors in order to fly. Unlike a helicopter and rotor kites do not have an engine powering their rotors, but while an autogyro has an engine providing forward thrust that keeps the rotor turning, a rotor kite has no engine at all, relies on either being carried aloft and dropped from another aircraft, or by being towed into the air behind a car or boat. A rotary wing is characterised by the number of blades; this is between two and six per driveshaft. A rotorcraft may have one or more rotors.
Various rotor configurations have been used: One rotor. Powered rotors require compensation for the torque reaction causing yaw, except in the case of tipjet drive. One rotor rotorcraft are called monocopters. Two rotors; these rotate in opposite directions cancelling the torque reaction so that no tail rotor or other yaw stabiliser is needed. These rotors can be laid out as Tandem – One in front of the other. Transverse – Side by side. Coaxial – One rotor disc above the other, with concentric drive shafts. Intermeshing – Twin rotors at an acute angle from each other, whose nearly-vertical driveshafts are geared together to synchronise their rotor blades so that they intermesh called a synchropter. Three rotors. An uncommon configuration. All three rotors turned in the same direction and yaw compensation was provided by inclining each rotor axis to generate rotor thrust components that opposed torque. Four rotors. Referred to as the quadcopter or quadrotor. Two rotors turn clockwise and two counter-clockwise.
More than four rotors. Referred to as multirotors, or sometimes individually as hexacopters and octocopter, these configurations have matched sets of rotors turning in opposite directions, they are popular for unmanned aerial vehicles. Some rotary wing aircraft are designed to stop the rotor for forward flight so that it acts as a fixed wing. For vertical flight and hovering it spins to act as a rotary wing or rotor, for forward flight at speed it stops to act as a fixed wing providing some or all of the lift required. Additional fixed wings may be provided to help with stability and control and to provide auxiliary lift. An early American proposal was the conversion of the Lockheed F-104 Starfighter with a triangular rotor wing; the idea was revisited by Hughes. The Sikorsky S-72 research aircraft underwent extensive flight testing. In 1986 the Sikorsky S-72 Rotor Systems Research Aircraft was fitted with a four-bladed stopped rotor, known as the X-wing; the programme was cancelled two years before the rotor had flown.
The canard rotor/wing concept added a "canard" foreplane as well as a conventional tailplane, offloading the rotor wing and providing control du
A turboprop engine is a turbine engine that drives an aircraft propeller. In its simplest form a turboprop consists of an intake, combustor, a propelling nozzle. Air is compressed by the compressor. Fuel is added to the compressed air in the combustor, where the fuel-air mixture combusts; the hot combustion gases expand through the turbine. Some of the power generated by the turbine is used to drive the compressor; the rest is transmitted through the reduction gearing to the propeller. Further expansion of the gases occurs in the propelling nozzle, where the gases exhaust to atmospheric pressure; the propelling nozzle provides a small proportion of the thrust generated by a turboprop. In contrast to a turbojet, the engine's exhaust gases do not contain enough energy to create significant thrust, since all of the engine's power is used to drive the propeller. Exhaust thrust in a turboprop is sacrificed in favour of shaft power, obtained by extracting additional power from turbine expansion. Owing to the additional expansion in the turbine system, the residual energy in the exhaust jet is low.
The exhaust jet produces around or less than 10% of the total thrust. A higher proportion of the thrust comes from less at higher speeds. Turboprops can have bypass ratios up to 50-100 although the propulsion airflow is less defined for propellers than for fans; the propeller is coupled to the turbine through a reduction gear that converts the high RPM/low torque output to low RPM/high torque. The propeller itself is a constant speed type similar to that used with larger reciprocating aircraft engines. Unlike the small diameter fans used in turbofan jet engines, the propeller has a large diameter that lets it accelerate a large volume of air; this permits a lower airstream velocity for a given amount of thrust. As it is more efficient at low speeds to accelerate a large amount of air by a small degree than a small amount of air by a large degree, a low disc loading increases the aircraft's energy efficiency, this reduces the fuel use. Propellers lose efficiency as aircraft speed increases, so turboprops are not used on high-speed aircraft above Mach 0.6-0.7.
However, propfan engines, which are similar to turboprop engines, can cruise at flight speeds approaching Mach 0.75. To increase propeller efficiency, a mechanism can be used to alter their pitch relative to the airspeed. A variable-pitch propeller called a controllable-pitch propeller, can be used to generate negative thrust while decelerating on the runway. Additionally, in the event of an engine failure, the pitch can be adjusted to a vaning pitch, thus minimizing the drag of the non-functioning propeller. While most modern turbojet and turbofan engines use axial-flow compressors, turboprop engines contain at least one stage of centrifugal compression. Centrifugal compressors have the advantage of being simple and lightweight, at the expense of a streamlined shape. While the power turbine may be integral with the gas generator section, many turboprops today feature a free power turbine on a separate coaxial shaft; this enables the propeller to rotate independent of compressor speed. Residual thrust on a turboshaft is avoided by further expansion in the turbine system and/or truncating and turning the exhaust 180 degrees, to produce two opposing jets.
Apart from the above, there is little difference between a turboprop and a turboshaft. Alan Arnold Griffith had published a paper on turbine design in 1926. Subsequent work at the Royal Aircraft Establishment investigated axial turbine designs that could be used to supply power to a shaft and thence a propeller. From 1929, Frank Whittle began work on centrifugal turbine designs that would deliver pure jet thrust; the world's first turboprop was designed by the Hungarian mechanical engineer György Jendrassik. Jendrassik published a turboprop idea in 1928, on 12 March 1929 he patented his invention. In 1938, he built a small-scale experimental gas turbine; the larger Jendrassik Cs-1, with a predicted output of 1,000 bhp, was produced and tested at the Ganz Works in Budapest between 1937 and 1941. It was of axial-flow design with 15 compressor and 7 turbine stages, annular combustion chamber and many other modern features. First run in 1940, combustion problems limited its output to 400 bhp. In 1941,the engine was abandoned due to war, the factory was turned over to conventional engine production.
The world's first turboprop engine that went into mass production was designed by a German engineer, Max Adolf Mueller, in 1942. The first mention of turboprop engines in the general public press was in the February 1944 issue of the British aviation publication Flight, which included a detailed cutaway drawing of what a possible future turboprop engine could look like; the drawing was close to what the future Rolls-Royce Trent would look like. The first British turboprop engine was the Rolls-Royce RB.50 Trent, a converted Derwent II fitted with reduction gear and a Rotol 7 ft 11 in five-bladed propeller. Two Trents were fitted to Gloster Meteor EE227 — the sole "Trent-Meteor" — which thus became the world's first turboprop-powered aircraft, albeit a test-bed not intended for production, it first flew on 20 September 1945. From their experience with the Trent, Rolls-Royce developed the Rolls-Royce Clyde, the first turboprop engine to be type certificated for military and civil use, the Dart, which became one of the most reliable turboprop engines built.
Dart production continued for more than fifty years. The Dart-powered Vickers Vi
Oil pump (internal combustion engine)
The oil pump in an internal combustion engine circulates engine oil under pressure to the rotating bearings, the sliding pistons and the camshaft of the engine. This lubricates the bearings, allows the use of higher-capacity fluid bearings and assists in cooling the engine; as well as its primary purpose for lubrication, pressurized oil is used as a hydraulic fluid to power small actuators. One of the first notable uses in this way was for hydraulic tappets in valve actuation. Common recent uses may include the tensioner for a timing belt or variators for variable valve timing systems; the type of pump used varies. Gear pumps trochoid pumps and vane pumps are all used. Plunger pumps have been used in the past, but these are now only used for small engines. To avoid the need for priming, the pump is always mounted low-down, either submerged or around the level of the oil in the sump. A short pick-up pipe with a simple wire-mesh strainer reaches to the bottom of the sump. For simplicity and reliability, mechanical pumps are used, driven by mechanical geartrains from the crankshaft.
Reducing pump speed is beneficial and so it is usual to drive the pump from the cam or distributor shaft, which turns at half engine speed. Placing the oil pump low-down uses a near-vertical drive shaft, driven by helical skew gears from the camshaft; some engines, such as the Fiat twin cam engine of 1964, began as OHV engines with an oil pump driven from a conventional camshaft in the cylinder block. When the twin overhead cam engine was developed, the previous oil pump arrangement was retained and the camshaft became a shortened stub shaft; when the distributor position was moved from the previous block-mount to being mounted on the cylinder head camshafts, the oil pump drive remained in the same position, the unused distributor position now covered by a blanking plate. Small engines, or scooters may have internal gear pumps mounted directly on their crankshaft. For reliability, it is rare to use an external drive mechanism, either a separate belt drive or external gears, although camshaft-driven pumps rely on the same timing belt.
Additional separate belts are sometimes used where dry sump pumps have been added to engines during tuning. Electric oil pumps are not used, again for reliability. Some'turbo timer' electric auxiliary oil pumps are sometimes fitted to turbocharged engines; these are a second oil pump that continues to run after the engine has stopped, providing cooling oil to the hot bearings of a turbocharger for some minutes, whilst it cools down. These are supplementary pumps and do not replace the main, oil pump; the oiling system addresses the need to properly lubricate an engine. Properly lubricating an engine not only reduces friction between moving parts but is the main method by which heat is removed from pistons and shafts. Failing to properly lubricate an engine will result in engine failure; the oil pump forces the motor oil through the passages in the engine to properly distribute oil to different engine components. In a common oiling system, oil is drawn out of the oil sump through a wire mesh strainer that removes some of the larger pieces of debris from the oil.
The flow made by the oil pump allows the oil to be distributed around the engine. In this system, oil flows through an oil filter and sometimes an oil cooler, before going through the engine’s oil passages and being dispersed to lubricate pistons, springs, valve stems, more; the oil pressure generated in most engines should be about 10 psi per every 1000 revolutions per minute, peaking around 55-65 psi. Local pressure is far higher than the 50, 60 psi &c. set by the pump’s relief valve, will reach hundreds of psi. This higher pressure is developed by the relative speeds in feet per second of the crankshaft journal itself against the bearing, the bearing width, oil viscosity, temperature, balanced against the bearing clearance. All pump pressure does is “fill in the hole” and refresh the oil in the annular space faster than the leak expels it; this is why low-speed engines have large journals, with only modest pump size and pressure. Low pressure indicates; the oil pressure at the pump outlet, what opens the pressure relief valve, is the resistance to flow caused by the bearing clearances and restrictions.
The oil pressure gauge, or warning lamp, gives only the pressure at the point where its sender enters that part of the pressurized system – not everywhere, not an average, nor a generalized picture of the systemic pressure. Despite the frequent comparison to hydraulic engineering theory, this is not a “closed system” in which oil pressure is balanced and identical everywhere. All engines are "open systems"; the bearings farthest from the pump always have the lowest pressure because of the number of leaks between the pump and that bearing. Excess bearing clearance increases the pressure loss between the last bearing in a series. Depending on condition, an engine may have acceptable gauge pressure, still only 5 psi pressure at one connecting rod, which will fail under high load; the pressure is created by the resistance to the flow of the oil around the engine. So, the pressure of the oil may vary during operation, with temperature, engine speed, wear on the engine. Colder oil temperature can cause higher pressure, as the oil is thicker, while higher engine speeds cause the pump to run faster and pus
A piston ring is a split ring that fits into a groove on the outer diameter of a piston in a reciprocating engine such as an internal combustion engine or steam engine. The main functions of piston rings in reciprocating engines are: Sealing the combustion chamber so that there is minimal loss of gases to the crank case. Improving heat transfer from the piston to the cylinder wall. Maintaining the proper quantity of the oil between the piston and the cylinder wall Regulating engine oil consumption by scraping oil from the cylinder walls back to the sump; the gap in the piston ring compresses to a few thousandths of an inch. Piston rings are a major factor in identifying if an engine is four stroke. Three piston rings suggest that it is a four stroke engine while two piston rings suggest that it is a two stroke engine. Most piston rings are made of a hard and somewhat brittle cast iron; the split piston ring was invented by John Ramsbottom who reported the benefits to the Institution of Mechanical Engineers in 1854.
It soon replaced the hemp packing hitherto used in steam engines. The use of piston rings at once reduced the frictional resistance, the leakage of steam, the mass of the piston, leading to significant increases in power and efficiency and longer maintenance intervals. Piston rings have been an area of considerable focus and development for internal combustion engines; the needs of diesel engines and small piston-ported two-stroke engines have been difficult. Piston rings may account for a considerable proportion of the total friction in the engine, as much as 24%; this high friction is a result of the design compromises needed to achieve good sealing and long lifetime. Sealing is achieved by multiple rings, each with their own function, using a metal-on-metal sliding contact. Rings are sprung to increase this contact force and to maintain a close seal, either by the stiffness of the ring itself or by a separate spring behind the seal ring, it is important that rings float in their grooves within the piston, so that they can stay in contact with the cylinder.
Rings binding in the piston due to a build-up of either combustion products or a breakdown of the lubricating oil, is a common cause of failure for diesel engines. Lubrication of piston rings is difficult and has been a driving force to improvements in the quality of motor oil; the oil must survive harsh conditions with a high-speed sliding contact. Lubrication is difficult as the rings have an oscillating motion rather than continuous rotation, as for a bearing journal. At the limits of piston movement, the ring reverses direction; this disrupts the normal oil wedge effect of a hydrodynamic bearing, leading to pronounced wear and the formation of a'step' in the cylinder bore around the height of the upper ring. Noting that some sleeve valve engines suffered far less from such wear, complex designs such as a rotating cylinder liner have been considered, just to address this problem. Most automotive pistons have three rings: The top two, while controlling oil, are for compression sealing. Meanwhile, the lower ring is for controlling the supply of oil to the liner, which lubricates the piston skirt and the compression rings.
At least two piston rings are found on most cylinder combinations. Typical compression ring designs will have an rectangular cross section or a keystone cross section; the periphery will have either a barrel profile or a taper napier form. There are some taper-faced top rings as well, on some old engines simple plain-faced rings were used. Oil control rings are of three types: single piece cast iron helical spring backed cast iron or steel multipiece steelThe spring-backed oil rings and the cast iron oil rings have the same range of peripheral forms, which consist of two scraping lands of various detailed form; the multipiece oil control rings consist of two rails or segments with a spacer-expander spring which keeps the two rails apart and provides the radial load. The piston might be a loose fit in the cylinder. If it were a tight fit, it would expand as it might stick tight in the cylinder. If a piston sticks it could cause serious damage to the engine. On the other hand, if there is too much clearance between the piston and cylinder walls, the ultimate result will be insufficient sealing of the piston rings against the cylinder walls, thus much of the pressure from the burning gasoline vapour will leak past the piston and into the crankcase.
In such a situation, the push on the piston from combustion will be much less effective in delivering power. Piston rings are subject to wear as they move up and down the cylinder bore due to their own inherent load and due to the gas load acting on the ring. To minimize this, they are made of wear-resistant materials, such as cast iron and steel, are coated or treated to enhance the wear resistance. In two-stroke engines, the port design is additionally critical to ring life. In modern motorcycle engines, various proprietary shapes are used to help maximize ring longevity. Examples include specialized port shapes such as tapered serrations and the use of various combinations of heat-treating and special coatings applied by PVD processes and other techniques. Top ring and oil control rings will be coated with chromium, or Nitrided plasma sprayed or have a PVD ceramic coating. For enhanced scuff resistance and further improved wear, most m
Capacitor discharge ignition
Capacitor discharge ignition or thyristor ignition is a type of automotive electronic ignition system, used in outboard motors, lawn mowers, small engines, turbine-powered aircraft, some cars. It was developed to overcome the long charging times associated with high inductance coils used in inductive discharge ignition systems, making the ignition system more suitable for high engine speeds; the capacitive-discharge ignition uses capacitor discharge current to the coil to fire the spark plugs. The history of the capacitor discharge ignition system can be traced back to the 1890s when it is believed that Nikola Tesla was the first to propose such an ignition system. In U. S. patent #609250 first filed February 17, 1897, Tesla writes'Any suitable moving portion of the apparatus is caused to mechanically control the charging of a condenser and its discharge through a circuit in inductive relation to a secondary circuit leading to the terminals between which the discharge is to occur, so that at the desired intervals the condenser may be discharged through its circuit and induce in the other circuit a current of high potential which produces the desired discharge.'
The patent describes generally with a drawing, a mechanical means to accomplish its purpose. This was put into practice starting in 1906 on the Ford Model K; the Model K had dual ignition systems, one of, the Holley-Huff Magneto, or Huff System, manufactured by the Holley Brothers Company. It was designed by Edward S. Huff with US patent #882003 filed July 1, 1905 and assigned to Henry Ford; the system used an engine driven DC generator that charged a capacitor and discharged the capacitor through the ignition coil primary winding. An excerpt from the'Motorway' Jan 11 1906, describes its use on Ford six cylinder cars:'The efficiency of the Ford Magneto is shown by the fact that the instant it is switched in the car will pick up speed and, without changing the position of the ignition control lever, will run at least ten miles an hour faster.' It was the Robert Bosch company. During World War Two, Bosch had fitted thyratron CD ignitions to some piston engined fighter aircraft. With a CD ignition, an aeroplane engine did not need a warm up period for reliable ignition and so a fighter aircraft could take flight more as a result.
This early German system used a rotary DC converter along with fragile tube circuitry, was not suited to life in a fighter aircraft. Failures occurred within only a few hours; the quest for a reliable electronic means of producing a CD ignition began in earnest during the 1950s. In the mid-1950s, the Engineering Research Institute of the University of Michigan in cooperation with Chrysler Corporation in the United States worked to find a method to produce a viable solution, they were unsuccessful, but did provide much data on the advantages of such a system, should one be built. Namely. A few engineers and hobbyists had built CD ignitions throughout the 1950s using thyratrons. However, thyratrons were unsuitable for use in automobiles for two reasons, they required a warm-up period, a nuisance, were vulnerable to vibration which drastically shortened their lifetime. In an automotive application, the thyratron CD ignition would fail in either months; the unreliability of those early thyratron CD ignitions made them unsuitable for mass production despite providing short term benefits.
One company at least, Tung-Sol marketed a thyratron CD ignition, model Tung-Sol EI-4 in 1962, but it was expensive. Despite the failings of thyratron CD ignitions, the improved ignition that they gave made them a worthwhile addition for some drivers. For the Wankel powered NSU Spider of 1964, Bosch resurrected its thyratron method for a CD ignition and used this up until at least 1966, it suffered the same reliability problems as the Tung-Sol EI-4. It was the SCR, Silicon-controlled rectifier or thyristor invented in the late 1950s that replaced the troublesome thyratron, paved the way for a reliable solid-state CD ignition; this was thanks to his team at General Electric. The SCR was rugged with an indefinite lifetime, but prone to unwanted trigger impulses which would turn the SCR'on'. Unwanted trigger impulses in early attempts at using SCRs for CD ignitions were caused by electrical interference, but the main culprit proved to be'points bounce'. Points bounce is a feature of a points-triggered system.
In the standard system with points, ignition coil, ignition points bounce prevents the coil from saturating as RPM increases resulting in a weak spark, thus limiting high speed potential. In a CD ignition, at least those early attempts, the points bounce created unwanted trigger pulses to the SCR that resulted in a series of weak, untimed sparks that caused extreme misfiring. There were two possible solutions to the problem; the first would be to develop another means of triggering the discharge of the capacitor to one discharge per power stroke by replacing the points with something else. This could be done magnetically or optically, but that would necessitate more electronics and an expensive distributor; the other option was to keep the points, as they were in use and reliable, find a way to overcome the'points bounce' problem. This was accomplished in April 1962 by a Canadia
Engine tuning is the adjustment or modification of the internal combustion engine or Engine Control Unit to yield optimal performance and increase the engine's power output, economy, or durability. These goals may be mutually exclusive. Tuning can include a wide variety of adjustments and modifications, such as the routine adjustment of the carburetor and ignition system to significant engine overhauls. Performance tuning of an engine can involve revising some of the design decisions taken during the development of the engine. Setting the idle speed, air-fuel ratio, carburetor balance, spark plug and distributor point gaps, ignition timing were regular maintenance tasks for older engines and are the final but essential steps in setting up a racing engine. On modern engines equipped with electronic ignition and fuel injection, some or all of these tasks are automated but they still require periodic calibration; the term "tune-up" denotes the routine servicing of the engine to meet the manufacturer's specifications.
Tune-ups are needed periodically according to the manufacturer's recommendations to ensure the vehicle runs as expected. Modern automobile engines require a small number of tune-ups over the course of an approximate 250,000-kilometre or a 10-year, lifespan; this can be attributed to improvements in the production process in which imperfections and errors reduced by computer automation, significant improvement in the quality of consumables such as the availability of synthetic engine oil. Tune-ups may include the following: Adjustment of the carburetor idle speed and the air-fuel mixture and possible replacement of ignition system components like spark plugs, contact breaker points, distributor cap and distributor rotor, Replacement of the air filter and other filters, Inspection of emission controls, Valvetrain adjustment; the term "Italian tuneup" denotes the driving of a performance car, such as a Ferrari, by mechanics finishing the tune-up to burn out any built-up carbon. Modern engines are equipped with an engine management system /Engine Control Unit that can be adjusted to different settings, producing different performance levels.
Manufacturers produce a few engines that are used in a wider range of models and platforms. This allows the manufacturers to sell automobiles in various markets with different regulations without having to spend money developing and designing different engines to fit these regulations; this allows a single engine tuned to suit the particular buyer's market to be used by several brands. Remapping is the simplest form of stage one engine tuning. All modern vehicles have an ECU supplied by Bosch or Delphi Technologies; the ECU has firmware. These parameters include achieving the appropriate balance between fuel consumption, torque, fuel emissions and service intervals. Many factory firmware fail to utilise the full potential of the engine, as such leave the end-user with an under-tuned engine. Many manufacturers build one engine and use various firmwares, known as maps, to achieve different power levels to differentiate vehicles that have an identical engine; this gives users an opportunity to unlock more potential from the engine with a few changes to the factory software by reading and editing the factory firmware from the ECU using specialist tools plugged into the on-board diagnostics port.
The tools can be connected to the OBD port on any car to read the factory file, saved on the ECU. Software to read specific types of factory files is available. Parameters of factory files such as fuel injection, boost pressure, rail pressure, fuel pump pressure and ignition timing, are adjusted to safe limits that are set by an expert so the unlocked performance does not compromise the car's safe levels of reliability, fuel consumption and emissions; the map may be customized for city use, for on-track performance, or for an overall map giving power throughout the band in a linear manner. Once adjusted, the edited file is written back to the ECU with the same tools used for the initial reading, after which the engine is tested for performance, smoke levels, any problems. Fine-tuning is done according to the feedback, producing a better-performing and more efficient engine. Once remapping is completed, the suggestion is to reduce oil change intervals. Oil is a main factor for reliability. Remapping may increase the temperature of exhaust fumes.
Performance tuning is the tuning of an engine for motorsports. Many such automobiles never are built for show or leisure driving. In this context, the power output and responsiveness of the engine are of premium importance, but reliability and fuel efficiency are relevant. In races, the engine must be strong enough to withstand the additional stress placed upon it and the automobile must carry sufficient fuel, so it is far stronger and has higher performance than the mass-produced design on which it may be based; the transmission and other load-transmitting powertrain components may need to be modified to withstand the load from the increased power. Some people are interested in increasing the power output of an engine. Many techniques have been devised to achieve this, all of which operate to increase the rate and sometimes the efficiency, of combustion in the engine; this is achieved by putting more air-fuel mixture into the eng
Fuel injection is the introduction of fuel in an internal combustion engine, most automotive engines, by the means of an injector. All diesel engines use fuel injection by design. Petrol engines can use gasoline direct injection, where the fuel is directly delivered into the combustion chamber, or indirect injection where the fuel is mixed with air before the intake stroke. On petrol engines, fuel injection replaced carburetors from the 1980s onward; the primary difference between carburetors and fuel injection is that fuel injection atomizes the fuel through a small nozzle under high pressure, while a carburetor relies on suction created by intake air accelerated through a Venturi tube to draw the fuel into the airstream. The functional objectives for fuel injection systems can vary. All share the central task of supplying fuel to the combustion process, but it is a design decision how a particular system is optimized. There are several competing objectives such as: Power output Fuel efficiency Emissions performance Running on alternative fuels Reliability Driveability and smooth operation Initial cost Maintenance cost Diagnostic capability Range of environmental operation Engine tuningModern digital electronic fuel injection systems optimize these competing objectives more and than earlier fuel delivery systems.
Carburetors have the potential to atomize fuel better. Benefits of fuel injection include smoother and more consistent transient throttle response, such as during quick throttle transitions, easier cold starting, more accurate adjustment to account for extremes of ambient temperatures and changes in air pressure, more stable idling, decreased maintenance needs, better fuel efficiency. Fuel injection dispenses with the need for a separate mechanical choke, which on carburetor-equipped vehicles must be adjusted as the engine warms up to normal temperature. Furthermore, on spark ignition engines, fuel injection has the advantage of being able to facilitate stratified combustion which have not been possible with carburetors, it is only with the advent of multi-point fuel injection certain engine configurations such as inline five cylinder gasoline engines have become more feasible for mass production, as traditional carburetor arrangement with single or twin carburetors could not provide fuel distribution between cylinders, unless a more complicated individual carburetor per cylinder is used.
Fuel injection systems are able to operate regardless of orientation, whereas carburetors with floats are not able to operate upside down or in microgravity, such as encountered on airplanes. Fuel injection increases engine fuel efficiency. With the improved cylinder-to-cylinder fuel distribution of multi-point fuel injection, less fuel is needed for the same power output. Exhaust emissions are cleaner because the more precise and accurate fuel metering reduces the concentration of toxic combustion byproducts leaving the engine; the more consistent and predictable composition of the exhaust makes emissions control devices such as catalytic converters more effective and easier to design. Herbert Akroyd Stuart developed the first device with a design similar to modern fuel injection, using a'jerk pump' to meter out fuel oil at high pressure to an injector; this system was used on the hot-bulb engine and was adapted and improved by Bosch and Clessie Cummins for use on diesel engines. Fuel injection was in widespread commercial use in diesel engines by the mid-1920s.
An early use of indirect gasoline injection dates back to 1902, when French aviation engineer Leon Levavasseur installed it on his pioneering Antoinette 8V aircraft powerplant, the first V8 engine of any type produced in any quantity. Another early use of gasoline direct injection was on the Hesselman engine invented by Swedish engineer Jonas Hesselman in 1925. Hesselman engines use the ultra lean-burn principle, they are started on gasoline and switched to diesel or kerosene. Direct fuel injection was used in notable World War II aero-engines such as the Junkers Jumo 210, the Daimler-Benz DB 601, the BMW 801, the Shvetsov ASh-82FN. German direct injection petrol engines used injection systems developed by Bosch from their diesel injection systems. Versions of the Rolls-Royce Merlin and Wright R-3350 used single point fuel injection, at the time called "Pressure Carburettor". Due to the wartime relationship between Germany and Japan, Mitsubishi had two radial aircraft engines using fuel injection, the Mitsubishi Kinsei and the Mitsubishi Kasei.
Alfa Romeo tested one of the first electronic injection systems in Alfa Romeo 6C 2500 with "Ala spessa" body in 1940 Mille Miglia. The engine had six electrically operated injectors and were fed by a semi-high-pressure circulating fuel pump system. All diesel engines have fuel injected into the combustion chamber. See Diesel engine; the invention of mechanical injection for gasoline-fueled aviation engines was by the French inventor of the V8 engine configuration, Leon Levavasseur in 1902. Levavasseur designed the original Antoinette firm's series of V-form aircraft engines, starting with the Antoinette 8V to be used by the aircraft the Antoinette firm built that Levavasseur designed, flown from 1906 to the firm's demise in 1910, with t