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
Radiator (engine cooling)
Radiators are heat exchangers used for cooling internal combustion engines in automobiles but in piston-engined aircraft, railway locomotives, stationary generating plant or any similar use of such an engine. Internal combustion engines are cooled by circulating a liquid called engine coolant through the engine block, where it is heated through a radiator where it loses heat to the atmosphere, returned to the engine. Engine coolant is water-based, but may be oil, it is common to employ a water pump to force the engine coolant to circulate, for an axial fan to force air through the radiator. In automobiles and motorcycles with a liquid-cooled internal combustion engine, a radiator is connected to channels running through the engine and cylinder head, through which a liquid is pumped; this liquid may be water, but is more a mixture of water and antifreeze in proportions appropriate to the climate. Antifreeze itself is ethylene glycol or propylene glycol. A typical automotive cooling system comprises: a series of channels cast into the engine block and cylinder head, surrounding the combustion chambers with circulating liquid to carry away heat.
The radiator transfers the heat from the fluid inside to the air outside, thereby cooling the fluid, which in turn cools the engine. Radiators are often used to cool automatic transmission fluids, air conditioner refrigerant, intake air, sometimes to cool motor oil or power steering fluid. Radiators are mounted in a position where they receive airflow from the forward movement of the vehicle, such as behind a front grill. Where engines are mid- or rear-mounted, it is common to mount the radiator behind a front grill to achieve sufficient airflow though this requires long coolant pipes. Alternatively, the radiator may draw air from the flow over the top of the vehicle or from a side-mounted grill. For long vehicles, such as buses, side airflow is most common for engine and transmission cooling and top airflow most common for air conditioner cooling. Automobile radiators are constructed of a pair of header tanks, linked by a core with many narrow passageways, giving a high surface area relative to volume.
This core is made of stacked layers of metal sheet, pressed to form channels and soldered or brazed together. For many years radiators were made from copper cores soldered to brass headers. Modern radiators have aluminum cores, save money and weight by using plastic headers; this construction is more prone to failure and less repaired than traditional materials. An earlier construction method was the honeycomb radiator. Round tubes were swaged into hexagons at their ends stacked together and soldered; as they only touched at their ends, this formed what became in effect a solid water tank with many air tubes through it. Some vintage cars use radiator cores made from coiled tube, a less efficient but simpler construction. Radiators first used downward vertical flow, driven by a thermosyphon effect. Coolant is heated in the engine, becomes less dense, so rises; as the radiator cools the fluid, the coolant falls. This effect is sufficient for low-power stationary engines, but inadequate for all but the earliest automobiles.
All automobiles for many years have used centrifugal pumps to circulate the engine coolant because natural circulation has low flow rates. A system of valves or baffles, or both, is incorporated to operate a small radiator inside the vehicle; this small radiator, the associated blower fan, is called the heater core, serves to warm the cabin interior. Like the radiator, the heater core acts by removing heat from the engine. For this reason, automotive technicians advise operators to turn on the heater and set it to high if the engine is overheating, to assist the main radiator; the engine temperature on modern cars is controlled by a wax-pellet type of thermostat, a valve which opens once the engine has reached its optimum operating temperature. When the engine is cold, the thermostat is closed except for a small bypass flow so that the thermostat experiences changes to the coolant temperature as the engine warms up. Engine coolant is directed by the thermostat to the inlet of the circulating pump and is returned directly to the engine, bypassing the radiator.
Directing water to circulate only through the engine allows the engine to reach optimum operating temperature as as possible whilst avoiding localised "hot spots." Once the coolant reaches the thermostat's activation temperature, it opens, allowing water to flow through the radiator to prevent the temperature rising higher. Once at optimum temperature, the thermostat controls the flow of engine coolant to the radiator so that the engine continues to operate at optimum temperature. Under peak load conditions, such as driving up a steep hill whilst laden on a hot day, the thermostat will be approaching open because the engine will be producing near to maximum power while the velocity of air flow across the radiator is low. Conversely, when cruising fast downhill on a motorway on a cold night on a light throttle, the thermostat will be nearly clos
A camshaft is a shaft to which a cam is fastened or of which a cam forms an integral part. The camshaft was described in Turkey by Al-Jazari in 1206, he employed it as part of his automata, water-raising machines, water clocks such as the castle clock. The camshaft appeared in European mechanisms from the 14th century. Among the first cars to utilize engines with single overhead camshafts were the Maudslay designed by Alexander Craig and introduced in 1902 and the Marr Auto Car designed by Michigan native Walter Lorenzo Marr in 1903. In internal combustion engines with pistons, the camshaft is used to operate poppet valves, it consists of a cylindrical rod running the length of the cylinder bank with a number of oblong lobes protruding from it, one for each valve. The cam lobes force the valves open by pressing on the valve, or on some intermediate mechanism, as they rotate. Camshafts can be made out of several types of material; these include: Chilled iron castings: Commonly used in high volume production, chilled iron camshafts have good wear resistance since the chilling process hardens them.
Other elements are added to the iron before casting to make the material more suitable for its application. Billet Steel: When a high quality camshaft or low volume production is required, engine builders and camshaft manufacturers choose steel billet; this is a much more time consuming process, is more expensive than other methods. However, the finished product is far superior. CNC lathes, CNC milling machines, CNC camshaft grinders will be used during production. Different types of steel bar can be used, one example being EN40b; when manufacturing a camshaft from EN40b, the camshaft will be heat treated via gas nitriding, which changes the micro-structure of the material. It gives a surface hardness of 55-60 HRC; these types of camshafts can be used in high-performance engines. The relationship between the rotation of the camshaft and the rotation of the crankshaft is of critical importance. Since the valves control the flow of the air/fuel mixture intake and exhaust gases, they must be opened and closed at the appropriate time during the stroke of the piston.
For this reason, the camshaft is connected to the crankshaft either directly, via a gear mechanism, or indirectly via a belt or chain called a timing belt or timing chain. Direct drive using gears is unusual because of the cost; the reversing torque caused by the slope of the cams tends to cause gear rattle which for an all-metal gear train requires further expense of a cam damper. Rolls-Royce V8 used gear drive as, unlike chain, it could be made silent and to last the life of the engine. Where gears are used in cheaper cars, they tend to be made from resilient fibre rather than metal, except in racing engines that have a high maintenance routine. Fibre gears have a short life span and must be replaced much like a timing belt. In some designs the camshaft drives the distributor and the oil and fuel pumps; some vehicles may have the power steering pump driven by the camshaft. With some early fuel injection systems, cams on the camshaft would operate the fuel injectors. Honda redesigned the VF750 motorcycle from chain drive to the gear drive VFR750 due to insurmountable problems with the VF750 Hi-Vo inverted chain drive.
An alternative used in the early days of OHC engines was to drive the camshaft via a vertical shaft with bevel gears at each end. This system was, for example, used on the pre-World War I Mercedes Grand Prix cars. Another option was to use a triple eccentric with connecting rods. O. Bentley-designed engines and on the Leyland Eight. In a two-stroke engine that uses a camshaft, each valve is opened once for every rotation of the crankshaft. In a four-stroke engine, the valves are opened only half as often; the timing of the camshaft can be advanced to produce better low RPM torque, or retarded for better high RPM power. Changing cam timing moves the overall power produced by the engine down or up the RPM scale; the amount of change is little, affects valve to piston clearances. Refer to this video. Duration is the number of crankshaft degrees of engine rotation during which the valve is off the seat. In general, greater duration results in more horsepower; the RPM at which peak horsepower occurs is increased as duration increases at the expense of lower rpm efficiency.
Duration specifications can be misleading because manufacturers may select any lift point from which to advertise a camshaft's duration and sometimes will manipulate these numbers. The power and idle characteristics of a camshaft rated at a.006" lift point will be much different from one with the same rating at a.002" lift point. Many performance engine builders gauge a race profile's aggressiveness by looking at the duration at.020".050" and.200". The.020" number determines how responsive the motor will be and how much low end torque the motor will make. The.050" number is used to estimate where peak power will occur, the.200" number gives an estimate of the power potential. A secondary effect of increased duration can be increased overlap, the number of crankshaft degrees during which both intake and exhaust valves are off their seats, it is overlap which most affects idle quality, inasmuch as the "blow-through" of the intake charge back out thru the exhaust valve which occurs during overlap reduces engine efficiency, is greatest during low RPM operation.
In general, increasing a camshaft's duration increases the overlap, unless the intake and exhaust lobe centers are m
The static compression ratio, of an internal combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity. It is a fundamental specification for many common combustion engines. In a piston engine, it is the ratio between the volume of the cylinder and combustion chamber when the piston is at the bottom of its stroke, the volume of the combustion chamber when the piston is at the top of its stroke. For example, a cylinder and its combustion chamber with the piston at the bottom of its stroke may contain 1000 cc of air; when the piston has moved up to the top of its stroke inside the cylinder, the remaining volume inside the head or combustion chamber has been reduced to 100 cc the compression ratio would be proportionally described as 1000:100, or with fractional reduction, a 10:1 compression ratio. A high compression ratio is desirable because it allows an engine to extract more mechanical energy from a given mass of air–fuel mixture due to its higher thermal efficiency.
This occurs because internal combustion engines are heat engines, higher efficiency is created because higher compression ratios permit the same combustion temperature to be reached with less fuel, while giving a longer expansion cycle, creating more mechanical power output and lowering the exhaust temperature. It may be more helpful to think of it as an "expansion ratio", since more expansion reduces the temperature of the exhaust gases, therefore the energy wasted to the atmosphere. Diesel engines have a higher peak combustion temperature than petrol engines, but the greater expansion means they reject less heat in their cooler exhaust. Higher compression ratios will however make gasoline engines subject to engine knocking if lower octane-rated fuel is used; this can reduce efficiency or damage the engine if knock sensors are not present to modify the ignition timing. On the other hand, diesel engines operate on the principle of compression ignition, so that a fuel which resists autoignition will cause late ignition, which will lead to engine knock.
Static compression ratio is calculated by the formula C R = V d + V c V c Where: V d = displacement volume. This is the volume inside the cylinder displaced by the piston from the beginning of the compression stroke to the end of the stroke. V c = clearance volume; this is the volume of the space in the cylinder left at the end of the compression stroke. V d can be estimated by the cylinder volume formula V d = π 4 b 2 s Where: b = cylinder bore s = piston stroke lengthBecause of the complex shape of V c it is measured directly; this is done by filling the cylinder with liquid and measuring the volume of the used liquid. The compression ratio in a gasoline -powered engine will not be much higher than 10:1 due to potential engine knocking and not lower than 6:1; some production automotive engines built for high performance from 1955–1972, used high-octane leaded gasoline or'5 star' to allow compression ratios as high as 13.0:1. A technique used to prevent the onset of knock is the high "swirl" engine that forces the intake charge to adopt a fast circular rotation in the cylinder during compression that provides quicker and more complete combustion.
It is possible to manufacture gasoline engines with compression ratios of over 11:1 that can use 87 /2 fuel with the addition of variable valve timing and knock sensors to delay ignition timing. Such engines may not produce their full rated power using 87 octane gasoline under all circumstances, due to the delayed ignition timing. Direct fuel injection, which can inject fuel only at the time of fuel ignition, is another recent development which allows for higher compression ratios on gasoline engines; the compression ratio can be as high as 14:1 in engines with a'ping' or'knock' sensor and an electronic control unit. In 1981, Jaguar released a cylinder head; the cylinder head design was known as the "May Fireball" head. In 2012, Mazda released new petrol engines under the brand name SkyActiv with a 14:1 compression ratio, to be used in all Mazda vehicles by 2015; the SkyActiv engine achieves this compression ratio with ordinary unleaded gasoline through improved scavenging of exhaust gases, in addition to direct injection.
In a turbocharged or supercharged gasoline engine, the CR is customarily built at 10.5:1 or lower. This is due to the turbocharger/supercharger having compressed the air before it enters the cylinders. Port fuel injected engines run lower boost than direct fuel injected engines because port fuel inj
General Motors Company referred to as General Motors, is an American multinational corporation headquartered in Detroit that designs, manufactures and distributes vehicles and vehicle parts, sells financial services, with global headquarters in Detroit's Renaissance Center. It was founded by William C. Durant on September 16, 1908 as a holding company; the company is the largest American automobile manufacturer, one of the world's largest. As of 2018, General Motors is ranked #10 on the Fortune 500 rankings of the largest United States corporations by total revenue. General Motors manufactures vehicles in 37 countries, it owns or holds controlling interest in foreign brands such as Holden, Wuling and Jiefang. Annual worldwide sales volume reached a milestone of 10 million vehicles in 2016. In addition to its twelve brands, General Motors holds a 20% stake in IMM, a 77% stake in GM Korea, it has a number of joint-ventures, including Shanghai GM, SAIC-GM-Wuling and FAW-GM in China, GM-AvtoVAZ in Russia, GM Uzbekistan, General Motors India, General Motors Egypt, Isuzu Truck South Africa.
General Motors does business in more than 140 countries. General Motors is divided into four business segments: GM North America, GM International Operations, GM Cruze, GM Financial; the company operates a mobility division called Maven, which operates car-sharing services in the United States, is studying alternatives to individual vehicle ownership. GM Defense is General Motors' military defense division, catering to the needs of the military for advanced technology and propulsion systems for military vehicles. General Motors led global vehicle sales for 77 consecutive years from 1931 through 2007, longer than any other automaker, in 2012 was among the world's largest automakers by vehicle unit sales. General Motors acts in most countries outside the U. S. via wholly owned subsidiaries, but operates in China through 10 joint ventures. GM's OnStar subsidiary provides vehicle safety and information services. In 2009, General Motors shed several brands, closing Saturn and Hummer, emerged from a government-backed Chapter 11 reorganization.
In 2010, the reorganized GM made an initial public offering, one of the world's top five largest IPOs to date, returned to profitability that year. General Motors Company was formed with an escrow account set up by R S McLaughlin for 15 years of Buick Motors in 1907 on September 16, 1908, in Flint, Michigan, as a holding company controlled by William C. Durant, owner of Buick. At the beginning of the 20th century, there were fewer than 8,000 automobiles in the U. S. and Durant had become a leading manufacturer of horse-drawn vehicles in Flint helped by his purchase of the Carriage Gear patent from the McLaughlin family in Canada, in the 1880s and 1890s, before making his foray into the automotive industry in 1904 by purchasing the fledgling Buick Motor Company. GM's co-founder was Charles Stewart Mott, whose carriage company was merged into Buick prior to GM's creation in 1918. Over the years, Mott became the largest single stockholder in The USA, spent his life with his Mott Foundation, which has benefited the city of Flint, his adopted home.
GM acquired Oldsmobile that year. In 1909, Durant brought in Cadillac, Elmore and several others. In 1909, GM acquired the Reliance Motor Truck Company of Owosso and the Rapid Motor Vehicle Company of Pontiac, the predecessors of GMC Truck. Durant, along with R. S. McLaughlin, lost control of GM in 1910 to a bankers who held the Escrow account' trust, because of the large amount of debt taken on in its acquisitions, coupled with a collapse in new vehicle sales; the next year, Durant started the Chevrolet Motor Car Company in the U. S. and in Canada in 1915, through this, he and McLaughlin in Canada secretly purchased a controlling interest in GM. Durant regained control of the company after one of the most dramatic proxy wars in U. S. business history. Durant reorganized General Motors Holding Company into General Motors Company in 1916, merging Chevrolet with GM and allying General Motors of Canada Limited in 1918 after McLaughlin Traded his Outstanding Stocks for GM stocks to allow the Corporation in the USA.
Shortly thereafter, he again lost control, this time for good, after the new vehicle market collapsed. Alfred P. Sloan was picked to take charge of the corporation, led it to its post-war global dominance when the seven manufacturing facilities operated by Chevrolet before Chevrolet acquired the company began to contribute to GM operations; these facilities were added to the individual factories that were exclusive to Cadillac, Oldsmobile and other companies acquired by the corporation. This unprecedented growth of GM would last into the early 1980s, when it employed 349,000 workers and operated 150 assembly plants in the USA. On July 10, 2009, General Motors emerged from government backed Chapter 11 reorganization after an initial filing on June 8, 2009. Through the Troubled Asset Relief Program the US Treasury invested $49.5 billion in General Motors and recovered $39 billion when it sold its shares on December 9, 2013 resulting in a loss of $10.3 billion. The Treasury invested an additional $17.2 billion into GM's former financing company, GMAC.
The shares in Ally were sold on December 2014 for $19.6 billion netting $2.4 billion. A study by the Center for Automotive Research found that the GM bailout saved 1.2 million jobs and preserved $34.9 billion in tax revenue. In 2009 General Motors of Canada Limited was not part of the General Motors Chapter 11 Bankruptcy, the company shed several brands
Horsepower is a unit of measurement of power, or the rate at which work is done. There are many different types of horsepower. Two common definitions being used today are the mechanical horsepower, about 745.7 watts, the metric horsepower, 735.5 watts. The term was adopted in the late 18th century by Scottish engineer James Watt to compare the output of steam engines with the power of draft horses, it was expanded to include the output power of other types of piston engines, as well as turbines, electric motors and other machinery. The definition of the unit varied among geographical regions. Most countries now use the SI unit watt for measurement of power. With the implementation of the EU Directive 80/181/EEC on January 1, 2010, the use of horsepower in the EU is permitted only as a supplementary unit; the development of the steam engine provided a reason to compare the output of horses with that of the engines that could replace them. In 1702, Thomas Savery wrote in The Miner's Friend: So that an engine which will raise as much water as two horses, working together at one time in such a work, can do, for which there must be kept ten or twelve horses for doing the same.
I say, such an engine may be made large enough to do the work required in employing eight, fifteen, or twenty horses to be maintained and kept for doing such a work… The idea was used by James Watt to help market his improved steam engine. He had agreed to take royalties of one third of the savings in coal from the older Newcomen steam engines; this royalty scheme did not work with customers who did not have existing steam engines but used horses instead. Watt determined; the wheel was 12 feet in radius. Watt judged. So: P = W t = F d t = 180 l b f × 2.4 × 2 π × 12 f t 1 m i n = 32, 572 f t ⋅ l b f m i n. Watt defined and calculated the horsepower as 32,572 ft⋅lbf/min, rounded to an 33,000 ft⋅lbf/min. Watt determined that a pony could lift an average 220 lbf 100 ft per minute over a four-hour working shift. Watt judged a horse was 50% more powerful than a pony and thus arrived at the 33,000 ft⋅lbf/min figure. Engineering in History recounts that John Smeaton estimated that a horse could produce 22,916 foot-pounds per minute.
John Desaguliers had suggested 44,000 foot-pounds per minute and Tredgold 27,500 foot-pounds per minute. "Watt found by experiment in 1782 that a'brewery horse' could produce 32,400 foot-pounds per minute." James Watt and Matthew Boulton standardized that figure at 33,000 foot-pounds per minute the next year. A common legend states that the unit was created when one of Watt's first customers, a brewer demanded an engine that would match a horse, chose the strongest horse he had and driving it to the limit. Watt, while aware of the trick, accepted the challenge and built a machine, even stronger than the figure achieved by the brewer, it was the output of that machine which became the horsepower. In 1993, R. D. Stevenson and R. J. Wassersug published correspondence in Nature summarizing measurements and calculations of peak and sustained work rates of a horse. Citing measurements made at the 1926 Iowa State Fair, they reported that the peak power over a few seconds has been measured to be as high as 14.9 hp and observed that for sustained activity, a work rate of about 1 hp per horse is consistent with agricultural advice from both the 19th and 20th centuries and consistent with a work rate of about 4 times the basal rate expended by other vertebrates for sustained activity.
When considering human-powered equipment, a healthy human can produce about 1.2 hp and sustain about 0.1 hp indefinitely. The Jamaican sprinter Usain Bolt produced a maximum of 3.5 hp 0.89 seconds into his 9.58 second 100-metre dash world record in 2009. When torque T is in pound-foot units, rotational speed is in rpm and power is required in horsepower: P / hp = T / × N / rpm 5252 The constant 5252 is the rounded value of /; when torque T is in inch pounds: P