147-524: A four-stroke (also four-cycle ) engine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The four separate strokes are termed: Four-stroke engines are the most common internal combustion engine design for motorized land transport, being used in automobiles , trucks , diesel trains , light aircraft and motorcycles . The major alternative design
294-433: 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
441-409: 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
588-447: A flathead engine a push rod is not necessary. The overhead cam design typically allows higher engine speeds because it provides the most direct path between cam and valve. Valve clearance refers to the small gap between a valve lifter and a valve stem that ensures that the valve completely closes. On engines with mechanical valve adjustment, excessive clearance causes noise from the valve train. A too-small valve clearance can result in
735-415: A full-size SUV usually travels 13 mpg (US) (18 L/100 km) city and 16 mpg (US) (15 L/100 km) highway. Pickup trucks vary considerably; whereas a 4 cylinder-engined light pickup can achieve 28 mpg (8 L/100 km), a V8 full-size pickup with extended cabin only travels 13 mpg (US) (18 L/100 km) city and 15 mpg (US) (15 L/100 km) highway. The average fuel economy for all vehicles on
882-428: 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,
1029-470: 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
1176-410: A rotor (Wankel engine) , or a nozzle ( jet engine ). This force moves 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
1323-594: 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
1470-404: 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
1617-673: A clear way as described in the UK Statutory Instrument 2004 No 1661. Since September 2005 a color-coded "Green Rating" sticker has been available in the UK, which rates fuel economy by CO 2 emissions: A: <= 100 g/km, B: 100–120, C: 121–150, D: 151–165, E: 166–185, F: 186–225, and G: 226+. Depending on the type of fuel used, for gasoline A corresponds to about 4.1 L/100 km (69 mpg ‑imp ; 57 mpg ‑US ) and G about 9.5 L/100 km (30 mpg ‑imp ; 25 mpg ‑US ). Ireland has
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#17327880664211764-427: A cold start, and then "extra urban" travel at various speeds up to 120 km/h which follows the urban test. A combined figure is also quoted showing the total fuel consumed in divided by the total distance traveled in both tests. Fuel economy can be expressed in two ways: Conversions of units: While the thermal efficiency (mechanical output to chemical energy in fuel) of petroleum engines has increased since
1911-533: A combined score of 16 or better is needed, so a car with a 10 for economy (greenhouse) and a 6 for emission or 6 for economy and 10 for emission, or anything in between would get the highest 5 star rating. The lowest rated car is the Ssangyong Korrando with automatic transmission, with one star, while the highest rated was the Toyota Prius hybrid. The Fiat 500, Fiat Punto and Fiat Ritmo as well as
2058-499: 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
2205-550: A controlled laboratory testing procedure to generate the fuel consumption data that they submit to the Government of Canada. This controlled method of fuel consumption testing, including the use of standardized fuels, test cycles and calculations, is used instead of on-road driving to ensure that all vehicles are tested under identical conditions and that the results are consistent and repeatable. Selected test vehicles are "run in" for about 6,000 km before testing. The vehicle
2352-404: A detailed analysis of the forces that oppose a vehicle's motion. In terms of physics, Force = rate at which the amount of work generated (energy delivered) varies with the distance traveled, or: Note: The amount of work generated by the vehicle's power source (energy delivered by the engine) would be exactly proportional to the amount of fuel energy consumed by the engine if the engine's efficiency
2499-465: A diesel-fueled car, and 5.0 L/100 km (47 mpg US , 56 mpg imp ) for a gasoline (petrol)-fueled car. The average consumption across the fleet is not immediately affected by the new vehicle fuel economy: for example, Australia's car fleet average in 2004 was 11.5 L/100 km (20.5 mpg US ), compared with the average new car consumption in the same year of 9.3 L/100 km (25.3 mpg US ) Fuel economy at steady speeds with selected vehicles
2646-508: A distance, or the distance traveled per unit volume of fuel consumed. Since fuel consumption of vehicles is a significant factor in air pollution, and since the importation of motor fuel can be a large part of a nation's foreign trade , many countries impose requirements for fuel economy. Different methods are used to approximate the actual performance of the vehicle. The energy in fuel is required to overcome various losses ( wind resistance , tire drag , and others) encountered while propelling
2793-452: 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
2940-408: 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
3087-731: 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
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#17327880664213234-493: A replica of the Lenoir engine in 1861, Otto became aware of the effects of compression on the fuel charge. In 1862, Otto attempted to produce an engine to improve on the poor efficiency and reliability of the Lenoir engine. He tried to create an engine that would compress the fuel mixture prior to ignition, but failed as that engine would run no more than a few minutes prior to its destruction. Many other engineers were trying to solve
3381-399: A result of higher fuel cost. A study indicates that a 10% increase in gas prices will eventually produce a 2.04% increase in fuel economy. One method by car makers to increase fuel efficiency is lightweighting in which lighter-weight materials are substituted in for improved engine performance and handling. Identical vehicles can have varying fuel consumption figures listed depending upon
3528-422: 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,
3675-481: 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
3822-416: 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
3969-600: A sticker on the windscreen showing the fuel consumption and the CO 2 emissions. Fuel consumption figures are expressed as urban , extra urban and combined , measured according to ECE Regulations 83 and 101 – which are the based on the European driving cycle ; previously, only the combined number was given. Australia also uses a star rating system, from one to five stars, that combines greenhouse gases with pollution, rating each from 0 to 10 with ten being best. To get 5 stars
4116-635: A top speed of 120 km/h (74.6 mph). EU fuel consumption numbers are often considerably lower than corresponding US EPA test results for the same vehicle. For example, the 2011 Honda CR-Z with a six-speed manual transmission is rated 6.1/4.4 L/100 km in Europe and 7.6/6.4 L/100 km (31/37 mpg ) in the United States. In the European Union advertising has to show carbon dioxide (CO 2 )-emission and fuel consumption data in
4263-582: A turbine system that converted waste heat into kinetic energy that it fed back into the engine's transmission. In 2005, BMW announced the development of the turbosteamer , a two-stage heat-recovery system similar to the Mack system that recovers 80% of the energy in the exhaust gas and raises the efficiency of an Otto engine by 15%. By contrast, a six-stroke engine may reduce fuel consumption by as much as 40%. Modern engines are often intentionally built to be slightly less efficient than they could otherwise be. This
4410-546: A vacuum with frictionless wheels could travel at any speed without consuming any energy beyond what is needed to get the car up to speed. Less ideally, any vehicle must expend energy on overcoming road load forces, which consist of aerodynamic drag, tire rolling resistance, and inertial energy that is lost when the vehicle is decelerated by friction brakes. With ideal regenerative braking , the inertial energy could be completely recovered, but there are few options for reducing aerodynamic drag or rolling resistance other than optimizing
4557-474: Is 235.215 x {\displaystyle \textstyle {\frac {235.215}{x}}} , where x {\displaystyle x} is value of L/100 km. For miles per Imperial gallon (4.5461 L) the formula is 282.481 x {\displaystyle \textstyle {\frac {282.481}{x}}} . In parts of Europe, the two standard measuring cycles for "litre/100 km" value are "urban" traffic with speeds up to 50 km/h from
Four-stroke engine - Misplaced Pages Continue
4704-427: Is 25% more miles per gallon for an efficient turbodiesel. For example, the current model Skoda Octavia, using Volkswagen engines, has a combined European fuel efficiency of 41.3 mpg ‑US (5.70 L/100 km) for the 105 bhp (78 kW) petrol engine and 52.3 mpg ‑US (4.50 L/100 km) for the 105 bhp (78 kW) — and heavier — diesel engine. The higher compression ratio
4851-460: Is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in 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 ),
4998-413: Is a contact surface on which the cam slides to open the valve. Many engines use one or more camshafts "above" a row (or each row) of cylinders, as in the illustration, in which each cam directly actuates a valve through a flat tappet. In other engine designs the camshaft is in the crankcase , in which case each cam usually contacts a push rod , which contacts a rocker arm that opens a valve, or in case of
5145-405: 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
5292-421: 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
5439-466: Is closer to the top. Diesel engines by their nature do not have concerns with pre-ignition. They have a concern with whether or not combustion can be started. The description of how likely Diesel fuel is to ignite is called the Cetane rating. Because Diesel fuels are of low volatility, they can be very hard to start when cold. Various techniques are used to start a cold Diesel engine, the most common being
5586-503: 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
5733-423: Is designed to provide efficiency at the expense of power density , and is used in some modern hybrid electric applications. The original Atkinson-cycle piston engine allowed the intake, compression, power, and exhaust strokes of the four-stroke cycle to occur in a single turn of the crankshaft and was designed to avoid infringing certain patents covering Otto-cycle engines. Due to the unique crankshaft design of
5880-542: 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
6027-415: 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
Four-stroke engine - Misplaced Pages Continue
6174-534: Is helpful in raising the energy efficiency, but diesel fuel also contains approximately 10% more energy per unit volume than gasoline which contributes to the reduced fuel consumption for a given power output. In 2002, the United States had 85,174,776 trucks, and averaged 13.5 miles per US gallon (17.4 L/100 km; 16.2 mpg ‑imp ). Large trucks, over 33,000 pounds (15,000 kg), averaged 5.7 miles per US gallon (41 L/100 km; 6.8 mpg ‑imp ). The average economy of automobiles in
6321-406: 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
6468-536: Is limited by the chemical composition of the fuel. There are several grades of fuel to accommodate differing performance levels of engines. The fuel is altered to change its self ignition temperature. There are several ways to do this. As engines are designed with higher compression ratios the result is that pre-ignition is much more likely to occur since the fuel mixture is compressed to a higher temperature prior to deliberate ignition. The higher temperature more effectively evaporates fuels such as gasoline, which increases
6615-545: Is necessary for emission controls such as exhaust gas recirculation and catalytic converters that reduce smog and other atmospheric pollutants. Reductions in efficiency may be counteracted with an engine control unit using lean burn techniques . In the United States, the Corporate Average Fuel Economy mandates that vehicles must achieve an average of 34.9 mpg ‑US (6.7 L/100 km; 41.9 mpg ‑imp ) compared to
6762-431: Is not immediately available due to the need to sharply increase engine RPM, to build up pressure and to spin up the turbo, before the turbo starts to do any useful air compression. The increased intake volume causes increased exhaust and spins the turbo faster, and so forth until steady high power operation is reached. Another difficulty is that the higher exhaust pressure causes the exhaust gas to transfer more of its heat to
6909-445: 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
7056-815: Is produced by Daimler AG and is only sold by one company in the United States. Furthermore, the world record in fuel economy of production cars is held by the Volkswagen Group , with special production models (labeled "3L") of the Volkswagen Lupo and the Audi A2 , consuming as little as 3 L/100 km (94 mpg ‑imp ; 78 mpg ‑US ). Diesel engines generally achieve greater fuel efficiency than petrol (gasoline) engines. Passenger car diesel engines have energy efficiency of up to 41% but more typically 30%, and petrol engines of up to 37.3%, but more typically 20%. A common margin
7203-413: Is regarded as the first car. In 1884, Otto's company, then known as Gasmotorenfabrik Deutz (GFD), developed electric ignition and the carburetor. In 1890, Daimler and Maybach formed a company known as Daimler Motoren Gesellschaft . Today, that company is Daimler-Benz . The Atkinson-cycle engine is a type of single stroke internal combustion engine invented by James Atkinson in 1882. The Atkinson cycle
7350-400: Is that the temperature rise of the compressed charge can cause pre-ignition. If this occurs at the wrong time and is too energetic, it can damage the engine. Different fractions of petroleum have widely varying flash points (the temperatures at which the fuel may self-ignite). This must be taken into account in engine and fuel design. The tendency for the compressed fuel mixture to ignite early
7497-514: 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
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#17327880664217644-579: Is the two-stroke cycle . Nikolaus August Otto was a traveling salesman for a grocery concern. In his travels, he encountered the internal combustion engine built in Paris by Belgian expatriate Jean Joseph Etienne Lenoir . In 1860, Lenoir successfully created a double-acting engine that ran on illuminating gas at 4% efficiency. The 18 litre Lenoir Engine produced only 2 horsepower. The Lenoir engine ran on illuminating gas made from coal, which had been developed in Paris by Philip Lebon . In testing
7791-421: Is the same regardless of power output, but this is not necessarily the case due to the operating characteristics of the internal combustion engine. For a vehicle whose source of power is a heat engine (an engine that uses heat to perform useful work), the amount of fuel energy that a vehicle consumes per unit of distance (level road) depends upon: Ideally, a car traveling at a constant velocity on level ground in
7938-428: Is then mounted on a chassis dynamometer programmed to take into account the aerodynamic efficiency, weight and rolling resistance of the vehicle. A trained driver runs the vehicle through standardized driving cycles that simulate trips in the city and on the highway. Fuel consumption ratings are derived from the emissions generated during the driving cycles. THE 5 CYCLE TEST: Tests 1, 3, 4, and 5 are averaged to create
8085-412: Is ultimately limited by material strength and lubrication . Valves, pistons and connecting rods suffer severe acceleration forces. At high engine speed, physical breakage and piston ring flutter can occur, resulting in power loss or even engine destruction. Piston ring flutter occurs when the rings oscillate vertically within the piston grooves they reside in. Ring flutter compromises the seal between
8232-471: The Miller cycle . Together, this redesign could significantly reduce fuel consumption and NO x emissions. [REDACTED] [REDACTED] [REDACTED] Starting position, intake stroke, and compression stroke. [REDACTED] [REDACTED] [REDACTED] Ignition of fuel, power stroke, and exhaust stroke. Internal combustion An internal combustion engine ( ICE or IC engine )
8379-611: The Otto engine , was created in 1876 by Nicolaus Otto . The term internal combustion engine usually refers to an engine in which combustion 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
8526-618: 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
8673-473: 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
8820-589: The fuel economy improvements the Atkinson cycle can provide. The diesel engine is a technical refinement of the 1876 Otto-cycle engine. Where Otto had realized in 1861 that the efficiency of the engine could be increased by first compressing the fuel mixture prior to its ignition, Rudolf Diesel wanted to develop a more efficient type of engine that could run on much heavier fuel. The Lenoir , Otto Atmospheric, and Otto Compression engines (both 1861 and 1876) were designed to run on Illuminating Gas (coal gas) . With
8967-426: 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. Fuel economy in automobiles The fuel economy of an automobile relates to the distance traveled by a vehicle and the amount of fuel consumed . Consumption can be expressed in terms of the volume of fuel to travel
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#17327880664219114-433: The Atkinson, its expansion ratio can differ from its compression ratio and, with a power stroke longer than its compression stroke, the engine can achieve greater thermal efficiency than a traditional piston engine. While Atkinson's original design is no more than a historical curiosity, many modern engines use unconventional valve timing to produce the effect of a shorter compression stroke/longer power stroke, thus realizing
9261-515: The Citroen C3 also received 5 stars. The greenhouse rating depends on the fuel economy and the type of fuel used. A greenhouse rating of 10 requires 60 or less grams of CO 2 per km, while a rating of zero is more than 440 g/km CO 2 . The highest greenhouse rating of any 2009 car listed is the Toyota Prius, with 106 g/km CO 2 and 4.4 L/100 km (64 mpg ‑imp ; 53 mpg ‑US ). Several other cars also received
9408-629: The NMSL, accounted for 9.5% of the U.S' vehicle-miles-traveled in 1973, but such free-flowing roads typically provide more fuel-efficient travel than conventional roads. A reasonably modern European supermini and many mid-size cars, including station wagons, may manage motorway travel at 5 L/100 km (47 mpg US/56 mpg imp) or 6.5 L/100 km in city traffic (36 mpg US/43 mpg imp), with carbon dioxide emissions of around 140 g/km. An average North American mid-size car travels 21 mpg (US) (11 L/100 km) city, 27 mpg (US) (9 L/100 km) highway;
9555-1047: The Netherlands. When the US National Maximum Speed Law 's 55 mph (89 km/h) speed limit was mandated from 1974 to 1995, there were complaints that fuel economy could decrease instead of increase. The 1997 Toyota Celica got better fuel-efficiency at 105 km/h (65 mph) than it did at 65 km/h (40 mph) (5.41 L/100 km (43.5 mpg ‑US ) vs 5.53 L/100 km (42.5 mpg ‑US )), although even better at 60 mph (97 km/h) than at 65 mph (105 km/h) (48.4 mpg ‑US (4.86 L/100 km) vs 43.5 mpg ‑US (5.41 L/100 km)), and its best economy (52.6 mpg ‑US (4.47 L/100 km)) at only 25 mph (40 km/h). Other vehicles tested had from 1.4 to 20.2% better fuel-efficiency at 90 km/h (56 mph) vs. 105 km/h (65 mph). Their best economy
9702-647: The USA. Most European vehicles cited in the CSI study run on diesel engines, which tend to achieve greater fuel efficiency than gas engines. Selling those cars in the United States is difficult because of emission standards, notes Walter McManus, a fuel economy expert at the University of Michigan Transportation Research Institute. "For the most part, European diesels don’t meet U.S. emission standards", McManus said in 2007. Another reason why many European models are not marketed in
9849-437: The United States in 2002 was 22.0 miles per US gallon (10.7 L/100 km; 26.4 mpg ‑imp ). By 2010 this had increased to 23.0 miles per US gallon (10.2 L/100 km; 27.6 mpg ‑imp ). Average fuel economy in the United States gradually declined until 1973, when it reached a low of 13.4 miles per US gallon (17.6 L/100 km; 16.1 mpg ‑imp ) and gradually has increased since, as
9996-408: The United States is that labor unions object to having the big 3 import any new foreign built models regardless of fuel economy while laying off workers at home. An example of European cars' capabilities of fuel economy is the microcar Smart Fortwo cdi, which can achieve up to 3.4 L/100 km (69.2 mpg US) using a turbocharged three-cylinder 41 bhp (30 kW) Diesel engine. The Fortwo
10143-515: The United States was 25.4 miles per US gallon (9.3 L/100 km). 2019 model year cars (ex. EVs) classified as "midsize" by the US EPA ranged from 12 to 56 mpg US (20 to 4.2 L/100 km) However, due to environmental concerns caused by CO 2 emissions, new EU regulations are being introduced to reduce the average emissions of cars sold beginning in 2012, to 130 g/km of CO 2 , equivalent to 4.5 L/100 km (52 mpg US , 63 mpg imp ) for
10290-619: 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
10437-524: The actual four-stroke and two-stroke cycles is not a simple task. However, the analysis can be simplified significantly if air standard assumptions are utilized. The resulting cycle, which closely resembles the actual operating conditions, is the Otto cycle. During normal operation of the engine, as the air/fuel mixture is being compressed, an electric spark is created to ignite the mixture. At low rpm this occurs close to TDC (Top Dead Centre). As engine rpm rises,
10584-426: The air has been compressed twice and then gains more potential volume in the combustion but it is only expanded in one stage. A turbocharger is a supercharger that is driven by the engine's exhaust gases, by means of a turbine . A turbocharger is incorporated into the exhaust system of a vehicle to make use of the expelled exhaust. It consists of a two piece, high-speed turbine assembly with one side that compresses
10731-489: 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
10878-540: The beginning of the automotive era , this is not the only factor in fuel economy. The design of automobile as a whole and usage pattern affects the fuel economy. Published fuel economy is subject to variation between jurisdiction due to variations in testing protocols. One of the first studies to determine fuel economy in the United States was the Mobil Economy Run , which was an event that took place every year from 1936 (except during World War II ) to 1968. It
11025-452: The bore diameter is larger than its stroke length is an oversquare engine, conversely, an engine with a bore diameter that is smaller than its stroke length is an undersquare engine. The valves are typically operated by a camshaft rotating at half the speed of the crankshaft . It has a series of cams along its length, each designed to open a valve during the appropriate part of an intake or exhaust stroke. A tappet between valve and cam
11172-448: The city driving fuel consumption rate. Tests 2, 4, and 5 are averaged to create the highway driving fuel consumption rate. In the European Union, passenger vehicles are commonly tested using two drive cycles, and corresponding fuel economies are reported as "urban" and "extra-urban", in liters per 100 km and (in the UK) in miles per imperial gallon. The urban economy is measured using
11319-619: 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
11466-455: 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
11613-432: 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
11760-410: 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
11907-400: 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
12054-401: 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
12201-413: 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
12348-435: The current standard of 25 mpg ‑US (9.4 L/100 km; 30.0 mpg ‑imp ). As automakers look to meet these standards by 2016, new ways of engineering the traditional internal combustion engine (ICE) have to be considered. Some potential solutions to increase fuel efficiency to meet new mandates include firing after the piston is farthest from the crankshaft, known as top dead centre , and applying
12495-431: 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
12642-411: 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
12789-407: 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
12936-414: 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
13083-413: 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
13230-453: 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
13377-474: The efficiency of the compression engine. Higher compression ratios also mean that the distance that the piston can push to produce power is greater (which is called the expansion ratio ). The octane rating of a given fuel is a measure of the fuel's resistance to self-ignition. A fuel with a higher numerical octane rating allows for a higher compression ratio, which extracts more energy from the fuel and more effectively converts that energy into useful work while at
13524-501: The energy generated by combustion is converted into useful rotational energy at the output shaft of the engine, while the remainder being lost due to waste heat, friction and engine accessories. There are a number of ways to recover some of the energy lost to waste heat. The use of a turbocharger in diesel engines is very effective by boosting incoming air pressure and in effect, provides the same increase in performance as having more displacement. The Mack Truck company, decades ago, developed
13671-543: 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
13818-411: The engine's performance and/or fuel efficiency could be improved by improving the overall efficiency of the cycle. It has been found that even if 6% of the entirely wasted heat is recovered it can increase the engine efficiency greatly. Many methods have been devised in order to extract waste heat out of an engine exhaust and use it further to extract some useful work, decreasing the exhaust pollutants at
13965-559: The engines burst, nearly killing Diesel. He persisted, and finally created a successful engine in 1893. The high-compression engine, which ignites its fuel by the heat of compression, is now called the diesel engine, whether a four-stroke or two-stroke design. The four-stroke diesel engine has been used in the majority of heavy-duty applications for many decades. It uses a heavy fuel containing more energy and requiring less refinement to produce. The most efficient Otto-cycle engines run near 30% thermal efficiency. The thermodynamic analysis of
14112-435: 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
14259-420: The first high-speed Otto engine in 1883. In 1885, they produced the first automobile to be equipped with an Otto engine. The Daimler Reitwagen used a hot-tube ignition system and the fuel known as Ligroin to become the world's first vehicle powered by an internal combustion engine. It used a four-stroke engine based on Otto's design. The following year, Karl Benz produced a four-stroke engined automobile that
14406-623: 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
14553-595: 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
14700-604: 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
14847-517: 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
14994-505: 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
15141-416: 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
15288-451: 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
15435-496: The impact that tire pressures have on the fuel efficiency. Environmental management systems EMAS , as well as good fleet management, includes record-keeping of the fleet fuel consumption. Quality management uses those figures to steer the measures acting on the fleets. This is a way to check whether procurement, driving, and maintenance in total have contributed to changes in the fleet's overall consumption. * highway ** combined From October 2008, all new cars had to be sold with
15582-434: The intake air, and the other side that is powered by the exhaust gas outflow. When idling, and at low-to-moderate speeds, the turbine produces little power from the small exhaust volume, the turbocharger has little effect and the engine operates nearly in a naturally aspirated manner. When much more power output is required, the engine speed and throttle opening are increased until the exhaust gases are sufficient to 'spool up'
15729-419: 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
15876-429: 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
16023-963: The market, include: Many aftermarket consumer products exist that are purported to increase fuel economy; many of these claims have been discredited. In the United States, the Environmental Protection Agency maintains a list of devices that have been tested by independent laboratories and makes the test results available to the public. Governments, various environmentalist organizations, and companies like Toyota and Shell Oil Company have historically urged drivers to maintain adequate air pressure in tires and careful acceleration/deceleration habits. Keeping track of fuel efficiency stimulates fuel economy-maximizing behavior. A five-year partnership between Michelin and Anglian Water shows that 60,000 liters of fuel can be saved on tire pressure. The Anglian Water fleet of 4,000 vans and cars are now lasting their full lifetime. This shows
16170-424: The mechanical parts of the engine. The rod-to-stroke ratio is the ratio of the length of the connecting rod to the length of the piston stroke. A longer rod reduces sidewise pressure of the piston on the cylinder wall and the stress forces, increasing engine life. It also increases the cost and engine height and weight. A "square engine" is an engine with a bore diameter equal to its stroke length. An engine where
16317-407: 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
16464-402: 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
16611-460: 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
16758-427: 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
16905-412: 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
17052-415: The piston speed for industrial engines to about 10 m/s. The output power of an engine is dependent on the ability of intake (air–fuel mixture) and exhaust matter to move quickly through valve ports, typically located in the cylinder head . To increase an engine's output power, irregularities in the intake and exhaust paths, such as casting flaws, can be removed, and, with the aid of an air flow bench ,
17199-421: The power output limits of an internal combustion engine relative to its displacement. Most commonly, the supercharger is always running, but there have been designs that allow it to be cut out or run at varying speeds (relative to engine speed). Mechanically driven supercharging has the disadvantage that some of the output power is used to drive the supercharger, while power is wasted in the high pressure exhaust, as
17346-409: 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
17493-403: 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
17640-469: The problem, with no success. In 1864, Otto and Eugen Langen founded the first internal combustion engine production company, NA Otto and Cie (NA Otto and Company). Otto and Cie succeeded in creating a successful atmospheric engine that same year. The factory ran out of space and was moved to the town of Deutz , Germany in 1869, where the company was renamed to Deutz Gasmotorenfabrik AG (The Deutz Gas Engine Manufacturing Company). In 1872, Gottlieb Daimler
17787-497: The radii of valve port turns and valve seat configuration can be modified to reduce resistance. This process is called porting , and it can be done by hand or with a CNC machine. An internal combustion engine is on average capable of converting only 40-45% of supplied energy into mechanical work. A large part of the waste energy is in the form of heat that is released to the environment through coolant, fins etc. If somehow waste heat could be captured and turned to mechanical energy,
17934-399: The ring and the cylinder wall, which causes a loss of cylinder pressure and power. If an engine spins too quickly, valve springs cannot act quickly enough to close the valves. This is commonly referred to as ' valve float ', and it can result in piston to valve contact, severely damaging the engine. At high speeds the lubrication of piston cylinder wall interface tends to break down. This limits
18081-484: The road is higher in Europe than the United States because the higher cost of fuel changes consumer behaviour . In the UK, a gallon of gas without tax would cost US$ 1.97, but with taxes cost US$ 6.06 in 2005. The average cost in the United States was US$ 2.61. European-built cars are generally more fuel-efficient than US vehicles. While Europe has many higher efficiency diesel cars, European gasoline vehicles are on average also more efficient than gasoline-powered vehicles in
18228-452: 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
18375-501: The same motivation as Otto, Diesel wanted to create an engine that would give small industrial companies their own power source to enable them to compete against larger companies, and like Otto, to get away from the requirement to be tied to a municipal fuel supply. Like Otto, it took more than a decade to produce the high-compression engine that could self-ignite fuel sprayed into the cylinder. Diesel used an air spray combined with fuel in his first engine. During initial development, one of
18522-684: The same principle as previously described. ( Firearms are also 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
18669-489: The same rating of 8.5 for greenhouse. The lowest rated was the Ferrari 575 at 499 g/km CO 2 and 21.8 L/100 km (13.0 mpg ‑imp ; 10.8 mpg ‑US ). The Bentley also received a zero rating, at 465 g/km CO 2 . The best fuel economy of any year is the 2004–2005 Honda Insight , at 3.4 L/100 km (83 mpg ‑imp ; 69 mpg ‑US ). Vehicle manufacturers follow
18816-406: The same time preventing engine damage from pre-ignition. High Octane fuel is also more expensive. Many modern four-stroke engines employ gasoline direct injection or GDI. In a gasoline direct-injected engine, the injector nozzle protrudes into the combustion chamber. The direct fuel injector injects gasoline under a very high pressure into the cylinder during the compression stroke, when the piston
18963-498: The same time. Use of the Rankine Cycle , turbocharging and thermoelectric generation can be very useful as a waste heat recovery system. One way to increase engine power is to force more air into the cylinder so that more power can be produced from each power stroke. This can be done using some type of air compression device known as a supercharger , which can be powered by the engine crankshaft. Supercharging increases
19110-520: The sources of energy loss in moving a vehicle may be summarized as follows: Fuel-efficiency decreases from electrical loads are most pronounced at lower speeds because most electrical loads are constant while engine load increases with speed. So at a lower speed, a higher proportion of engine horsepower is used by electrical loads. Hybrid cars see the greatest effect on fuel-efficiency from electrical loads because of this proportional effect. Technologies that may improve fuel efficiency, but are not yet on
19257-452: The speed of the flame front does not change so the spark point is advanced earlier in the cycle to allow a greater proportion of the cycle for the charge to combust before the power stroke commences. This advantage is reflected in the various Otto engine designs; the atmospheric (non-compression) engine operates at 12% efficiency whereas the compressed-charge engine has an operating efficiency around 30%. A problem with compressed charge engines
19404-400: 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
19551-437: The test cycle known as ECE-15, first introduced in 1970 by EC Directive 70/220/EWG and finalized by EEC Directive 90/C81/01 in 1999. It simulates a 4,052 m (2.518 mile) urban trip at an average speed of 18.7 km/h (11.6 mph) and at a maximum speed of 50 km/h (31 mph). The extra-urban driving cycle or EUDC lasts 400 seconds (6 minutes 40 seconds) at an average speed 62.6 km/h (39 mph) and
19698-446: The testing methods of the jurisdiction. Lexus IS 250 – petrol 2.5 L 4GR-FSE V6 , 204 hp (153 kW), 6 speed automatic, rear wheel drive Since the total force opposing the vehicle's motion (at constant speed) multiplied by the distance through which the vehicle travels represents the work that the vehicle's engine must perform, the study of fuel economy (the amount of energy consumed per unit of distance traveled) requires
19845-407: The turbocharger's turbine to start compressing much more air than normal into the intake manifold. Thus, additional power (and speed) is expelled through the function of this turbine. Turbocharging allows for more efficient engine operation because it is driven by exhaust pressure that would otherwise be (mostly) wasted, but there is a design limitation known as turbo lag . The increased engine power
19992-423: The use of a glow plug . The maximum amount of power generated by an engine is determined by the maximum amount of air ingested. The amount of power generated by a piston engine is related to its size (cylinder volume), whether it is a two-stroke engine or four-stroke design, volumetric efficiency , losses, air-to-fuel ratio, the calorific value of the fuel, oxygen content of the air and speed ( RPM ). The speed
20139-438: The valves not closing properly. This results in a loss of performance and possibly overheating of exhaust valves. Typically, the clearance must be readjusted each 20,000 miles (32,000 km) with a feeler gauge. Most modern production engines use hydraulic lifters to automatically compensate for valve train component wear. Dirty engine oil may cause lifter failure. Otto engines are about 30% efficient; in other words, 30% of
20286-416: The vehicle's shape and the tire design. Road load energy or the energy demanded at the wheels, can be calculated by evaluating the vehicle equation of motion over a specific driving cycle. The vehicle powertrain must then provide this minimum energy to move the vehicle and will lose a large amount of additional energy in the process of converting fuel energy into work and transmitting it to the wheels. Overall,
20433-728: The vehicle, and in providing power to vehicle systems such as ignition or air conditioning. Various strategies can be employed to reduce losses at each of the conversions between the chemical energy in the fuel and the kinetic energy of the vehicle. Driver behavior can affect fuel economy; maneuvers such as sudden acceleration and heavy braking waste energy. Electric cars do not directly burn fuel, and so do not have fuel economy per se, but equivalence measures, such as miles per gallon gasoline equivalent have been created to attempt to compare them. The fuel efficiency of motor vehicles can be expressed in multiple ways: The formula for converting to miles per US gallon (3.7854 L) from L/100 km
20580-423: 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,
20727-549: 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
20874-621: Was designed to provide real, efficient fuel efficiency numbers during a coast-to-coast test on real roads and with regular traffic and weather conditions. The Mobil Oil Corporation sponsored it and the United States Auto Club (USAC) sanctioned and operated the run. In more recent studies, the average fuel economy for new passenger car in the United States improved from 17 mpg (13.8 L/100 km) in 1978 to more than 22 mpg (10.7 L/100 km) in 1982. The average fuel economy for new 2020 model year cars, light trucks and SUVs in
21021-405: 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
21168-419: Was partly based on a belief that cars achieve maximum efficiency between 40 and 50 mph (65 and 80 km/h) and that trucks and buses were most efficient at 55 mph (89 km/h). In 1998, the U.S. Transportation Research Board footnoted an estimate that the 1974 National Maximum Speed Limit (NMSL) reduced fuel consumption by 0.2 to 1.0 percent. Rural interstates, the roads most visibly affected by
21315-399: Was reached at speeds of 40 to 90 km/h (25 to 56 mph) (see graph). Officials hoped that the 55 mph (89 km/h) limit, combined with a ban on ornamental lighting, no gasoline sales on Sunday, and a 15% cut in gasoline production, would reduce total gasoline consumption by 200,000 barrels a day, representing a 2.2% drop from annualized 1973 gasoline consumption levels. This
21462-846: Was studied in 2010. The most recent study indicates greater fuel efficiency at higher speeds than earlier studies; for example, some vehicles achieve better fuel economy at 100 km/h (62 mph) rather than at 70 km/h (43 mph), although not their best economy, such as the 1994 Oldsmobile Cutlass Ciera with the LN2 2.2L engine, which has its best economy at 90 km/h (56 mph) (8.1 L/100 km (29 mpg ‑US )), and gets better economy at 105 km/h (65 mph) than at 72 km/h (45 mph) (9.4 L/100 km (25 mpg ‑US ) vs 22 mpg ‑US (11 L/100 km)). The proportion of driving on high speed roadways varies from 4% in Ireland to 41% in
21609-406: Was technical director and Wilhelm Maybach was the head of engine design. Daimler was a gunsmith who had worked on the Lenoir engine. By 1876, Otto and Langen succeeded in creating the first internal combustion engine that compressed the fuel mixture prior to combustion for far higher efficiency than any engine created to this time. Daimler and Maybach left their employ at Otto and Cie and developed
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