Huge front-air-intakes-make-impression but we know you're focusing on that carbon-fiber hood. Mansorysays its ventilation channels optimize air flow to the
Huge front-air-intakes-make-impression
Large front air intakes to impress, but we know that you focus on the carbon fiber hood. Mansorysays its ventilation channels maximize airflow to the engine. Corresponding bits of carbon fiber can be found on the sides and rear of the car, where a roof and extremely tasteful rear spoiler Mansory X6 M expected to more stability at high speeds, but we guess most of these cars spend more time in more than 100 parking updates made on mph.The Mansory X5 X6 M is like M, but the body combined with standard X6 additional catchy bit of pushing this SUV top.We not more fans alloy wheels too large 23-inch, but it is hard to argue with larger brakes and a multi-piston brake or larger tires. A new exhaust system and revised engine electronics are responsible for the impetus to the 670th power alleged speed is electronically limited to 186 mph.The Mansory X6 M is wider too.
Inside, a new steering wheel to help customers benefit will be suspended. As explained by Mansory, the rest of the interior is open to the fabric: the cheerful company of changing the combinations of leather upholstery, Alcantara, wood, steel or aluminum finishes - just bring your checkbook
Huge front air intakes make an impression but we know you’re focusing on that carbon-fiber hood. Mansorysays its ventilation channels optimize air flow to the engine. Matching bits of carbon-fiber can be found on the sides and the rear of the car, where a roof and extremely tasteful rear lip spoiler supposedly give the Mansory X6 M more stability at high speeds, but we’re guessing most of these cars will spend more time in valet parking than at over 100 mph.The upgrades performed on the X6 M are similar to Mansory’s X5 M, but the X6’s standard bodystyle combined with added eye-catching bits push this SUV over the top.We aren’t fans of the too-large 23-inch light alloy wheels, but it’s hard to argue with larger brakes and a multi-piston brake system or the fatter tires. A new exhaust system and revised engine electronics are responsible for the horsepower boost to a claimed 670. Top speed is electronically limited to 186 mph.The Mansory X6 M is wider too. Inside, a new steering wheel helps customers make the most of the retuned suspension. As Mansory explains, the rest of the interior is an open canvas: the company will be happy to customize an interior with combinations of leather, Alcantara, wood, carbon, or aluminum trim — just bring your checkbook
Large front air intakes to impress, but we know that you focus on the carbon fiber hood. Mansorysays its ventilation channels maximize airflow to the engine. Corresponding bits of carbon fiber can be found on the sides and rear of the car, where a roof and extremely tasteful rear spoiler Mansory X6 M expected to more stability at high speeds, but we guess most of these cars spend more time in more than 100 parking updates made on mph.The Mansory X5 X6 M is like M, but the body combined with standard X6 additional catchy bit of pushing this SUV top.We not more fans alloy wheels too large 23-inch, but it is hard to argue with larger brakes and a multi-piston brake or larger tires. A new exhaust system and revised engine electronics are responsible for the impetus to the 670th power alleged speed is electronically limited to 186 mph.The Mansory X6 M is wider too.
Inside, a new steering wheel to help customers benefit will be suspended. As explained by Mansory, the rest of the interior is open to the fabric: the cheerful company of changing the combinations of leather upholstery, Alcantara, wood, steel or aluminum finishes - just bring your checkbook
Huge front air intakes make an impression but we know you’re focusing on that carbon-fiber hood. Mansorysays its ventilation channels optimize air flow to the engine. Matching bits of carbon-fiber can be found on the sides and the rear of the car, where a roof and extremely tasteful rear lip spoiler supposedly give the Mansory X6 M more stability at high speeds, but we’re guessing most of these cars will spend more time in valet parking than at over 100 mph.The upgrades performed on the X6 M are similar to Mansory’s X5 M, but the X6’s standard bodystyle combined with added eye-catching bits push this SUV over the top.We aren’t fans of the too-large 23-inch light alloy wheels, but it’s hard to argue with larger brakes and a multi-piston brake system or the fatter tires. A new exhaust system and revised engine electronics are responsible for the horsepower boost to a claimed 670. Top speed is electronically limited to 186 mph.The Mansory X6 M is wider too. Inside, a new steering wheel helps customers make the most of the retuned suspension. As Mansory explains, the rest of the interior is an open canvas: the company will be happy to customize an interior with combinations of leather, Alcantara, wood, carbon, or aluminum trim — just bring your checkbook
Huge front air intakes make an impression but we know you’re focusing on that carbon-fiber hood. Mansory says its ventilation channels optimize air flow to the engine. Matching bits of carbon-fiber can be found on the sides and the rear of the car, where a roof and extremely tasteful rear lip spoiler supposedly give the Mansory X6 M more stability at high speeds, but we’re guessing most of these cars will spend more time in valet parking than at over 100 mph.
The upgrades performed on the X6 M are similar to Mansory’s X5 M, but the X6′s standard bodystyle combined with added eye-catching bits push this SUV over the top.
We aren’t fans of the too-large 23-inch light alloy wheels, but it’s hard to argue with larger brakes and a multi-piston brake system or the fatter tires. A new exhaust system and revised engine electronics are responsible for the horsepower boost to a claimed 670. Top speed is electronically limited to 186 mph.
The Mansory X6 M is wider too. Inside, a new steering wheel helps customers make the most of the retuned suspension. As Mansory explains, the rest of the interior is an open canvas: the company will be happy to customize an interior with combinations of leather, Alcantara, wood, carbon, or aluminum trim — just bring your checkbook and imagination.
A diesel engine (also known as a compression-ignition engine) is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber. This is in contrast to spark-ignition engines such as a petrol engine (gasoline engine) or gas engine (using a gaseous fuel as opposed to gasoline), which uses a spark plug to ignite an air-fuel mixture. The engine was developed by Rudolf Diesel in 1893.
The diesel engine has the highest thermal efficiency of any regular internal or external combustion engine due to its very high compression ratio. Low-speed Diesel engines (as used in ships and other applications where overall engine weight is relatively unimportant) often have a thermal efficiency which exceeds 50 percent.[1][2]
Diesel engines are manufactured in two stroke and four stroke versions. They were originally used as a more efficient replacement for stationary steam engines. Since the 1910s they have been used in submarines and ships. Use in locomotives, trucks and electric generating plants followed later. In the 1930s, they slowly began to be used in a few automobiles. Since the 1970s, the use of diesel engines in larger on-road and off-road vehicles in the USA increased. As of 2007, about 50 percent of all new car sales in Europe are diesel.[3]
The world's largest diesel engine is currently a Wärtsilä Sulzer RT96-C Common Rail marine diesel of about 108,920 hp (81,220 kW) @ 102 rpm[4] output.[5]
was born in Paris in 1858 into a family of German expatriates.[6] He was educated at Munich Polytechnic. After graduation he was employed as a refrigerator engineer, but his true love lay in engine design. Diesel designed many heat engines, including a solar-powered air engine. In 1892 he received patents in Germany, Switzerland, the United Kingdom and filed in the United States for "Method of and Apparatus for Converting Heat into Work".[7] In 1893 he described a "slow-combustion engine" that first compressed air thereby raising its temperature above the igniting-point of the fuel, then gradually introducing fuel while letting the mixture expand "against resistance sufficiently to prevent an essential increase of temperature and pressure", then cutting off fuel and "expanding without transfer of heat".[citation needed] In 1894 and 1895 he filed patents and addenda in various countries for his Diesel engine; the first patents were issued in Spain (No.16,654), France (No.243,531) and Belgium (No.113,139) in December 1894, and in Germany (No.86,633) in 1895 and the United States (No.608,845) in 1898.[8] He operated his first successful engine in 1897. His engine was the first[citation needed] to prove that fuel could be ignited solely with high compression.
Though best known for his invention of the pressure-ignited heat engine that bears his name, Rudolf Diesel was also a well-respected thermal engineer and a social theorist. Diesel's inventions have three points in common: they relate to heat transfer by natural physical processes or laws; they involve markedly creative mechanical design; and they were initially motivated by the inventor's concept of sociological needs. Rudolf Diesel originally conceived the diesel engine to enable independent craftsmen and artisans to compete with industry.[9]
At Augsburg, on August 10, 1893, Rudolf Diesel's prime model, a single 10-foot (3.0 m) iron cylinder with a flywheel at its base, ran on its own power for the first time. Diesel spent two more years making improvements and in 1896 demonstrated another model with a theoretical efficiency of 75 percent, in contrast to the 10 percent efficiency of the steam engine. By 1898, Diesel had become a millionaire. His engines were used to power pipelines, electric and water plants, automobiles and trucks, and marine craft. They were soon to be used in mines, oil fields, factories, and transoceanic shipping.
The diesel internal combustion engine differs from the gasoline powered Otto cycle by using highly compressed hot air to ignite the fuel rather than using a spark plug (compression ignition rather than spark ignition).
In the true diesel engine, only air is initially introduced into the combustion chamber. The air is then compressed with a compression ratio typically between 15:1 and 22:1 resulting in 40-bar (4.0 MPa; 580 psi) pressure compared to 8 to 14 bars (0.80 to 1.4 MPa) (about 200 psi) in the petrol engine. This high compression heats the air to 550 °C (1,022 °F). At about the top of the compression stroke, fuel is injected directly into the compressed air in the combustion chamber. This may be into a (typically toroidal) void in the top of the piston or a pre-chamber depending upon the design of the engine. The fuel injector ensures that the fuel is broken down into small droplets, and that the fuel is distributed evenly. The heat of the compressed air vaporizes fuel from the surface of the droplets. The vapour is then ignited by the heat from the compressed air in the combustion chamber, the droplets continue to vaporise from their surfaces and burn, getting smaller, until all the fuel in the droplets has been burnt. The start of vaporisation causes a delay period during ignition and the characteristic diesel knocking sound as the vapor reaches ignition temperature and causes an abrupt increase in pressure above the piston. The rapid expansion of combustion gases then drives the piston downward, supplying power to the crankshaft.[23] Engines for scale-model aeroplanes use a variant of the Diesel principle but premix fuel and air via a carburation system external to the combustion chambers.
As well as the high level of compression allowing combustion to take place without a separate ignition system, a high compression ratio greatly increases the engine's efficiency. Increasing the compression ratio in a spark-ignition engine where fuel and air are mixed before entry to the cylinder is limited by the need to prevent damaging pre-ignition. Since only air is compressed in a diesel engine, and fuel is not introduced into the cylinder until shortly before top dead centre (TDC), premature detonation is not an issue and compression ratios are much higher.
Diesel's original engine injected fuel with the assistance of compressed air, which atomized the fuel and forced it into the engine through a nozzle (a similar principle to an aerosol spray). The nozzle opening was closed by a pin valve lifted by the camshaft to initiate the fuel injection before top dead centre (TDC). This is called an air-blast injection. Driving the three stage compressor used some power but the efficiency and net power output was more than any other combustion engine at that time.
Diesel engines in service today raise the fuel to extreme pressures by mechanical pumps and deliver it to the combustion chamber by pressure-activated injectors without compressed air. With direct injected diesels, injectors spray fuel through 4 to 12 small orifices in its nozzle. The early air injection diesels always had a superior combustion without the sharp increase in pressure during combustion. Research is now being performed and patents are being taken out to again use some form of air injection to reduce the nitrogen oxides and pollution, reverting to Diesel's original implementation with its superior combustion and possibly quieter operation. In all major aspects, the modern diesel engine holds true to Rudolf Diesel's original design, that of igniting fuel by compression at an extremely high pressure within the cylinder. With much higher pressures and high technology injectors, present-day diesel engines use the so-called solid injection system applied by Herbert Akroyd Stuart for his hot bulb engine. The indirect injection engine could be considered the latest development of these low speed hot bulb ignition engines
A vital component of all diesel engines is a mechanical or electronic governor which regulates the idling speed and maximum speed of the engine by controlling the rate of fuel delivery. Unlike Otto-cycle engines, incoming air is not throttled and a diesel engine without a governor cannot have a stable idling speed and can easily overspeed, resulting in its destruction. Mechanically governed fuel injection systems are driven by the engine's gear train.[24] These systems use a combination of springs and weights to control fuel delivery relative to both load and speed.[24] Modern electronically controlled diesel engines control fuel delivery by use of an electronic control module (ECM) or electronic control unit (ECU). The ECM/ECU receives an engine speed signal, as well as other operating parameters such as intake manifold pressure and fuel temperature, from a sensor and controls the amount of fuel and start of injection timing through actuators to maximise power and efficiency and minimise emissions. Controlling the timing of the start of injection of fuel into the cylinder is a key to minimizing emissions, and maximizing fuel economy (efficiency), of the engine. The timing is measured in degrees of crank angle of the piston before top dead centre. For example, if the ECM/ECU initiates fuel injection when the piston is 10 degrees before TDC, the start of injection, or timing, is said to be 10° BTDC. Optimal timing will depend on the engine design as well as its speed and load.
Advancing the start of injection (injecting before the piston reaches to its SOI-TDC) results in higher in-cylinder pressure and temperature, and higher efficiency, but also results in elevated engine noise and increased oxides of nitrogen (NOx) emissions due to higher combustion temperatures. Delaying start of injection causes incomplete combustion, reduced fuel efficiency and an increase in exhaust smoke, containing a considerable amount of particulate matter and unburned
Many configurations of fuel injection have been used over the past century (1901–2000).
Most present day (2008) diesel engines make use of a camshaft, rotating at half crankshaft speed, lifted mechanical single plunger high pressure fuel pump driven by the engine crankshaft. For each cylinder, its plunger measures the amount of fuel and determines the timing of each injection. These engines use injectors that are very precise spring-loaded valves that open and close at a specific fuel pressure. For each cylinder a plunger pump is connected to an injector with a high pressure fuel line. Fuel volume for each single combustion is controlled by a slanted groove in the plunger which rotates only a few degrees releasing the pressure and is controlled by a mechanical governor, consisting of weights rotating at engine speed constrained by springs and a lever. The injectors are held open by the fuel pressure. On high speed engines the plunger pumps are together in one unit.[32] Each fuel line should have the same length to obtain the same pressure delay.
A cheaper configuration on high speed engines with fewer than six cylinders is to use an axial-piston distributor pump, consisting of one rotating pump plunger delivering fuel to a valve and line for each cylinder (functionally analogous to points and distributor cap on an Otto engine).[24] This contrasts with the more modern method of having a single fuel pump which supplies fuel constantly at high pressure with a common rail (single fuel line common) to each injector. Each injector has a solenoid operated by an electronic control unit, resulting in more accurate control of injector opening times that depend on other control conditions, such as engine speed and loading, and providing better engine performance and fuel economy. This design is also mechanically simpler than the combined pump and valve design, making it generally more reliable, and less loud, than its mechanical counterpart.
Both mechanical and electronic injection systems can be used in either direct or indirect injection configurations.
Older diesel engines with mechanical injection pumps could be inadvertently run in reverse, albeit very inefficiently, as witnessed by massive amounts of soot being ejected from the air intake. This was often a consequence of push starting a vehicle using the wrong gear. Large ship diesels can run either way.
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Large front air intakes to impress, but we know that you focus on the carbon fiber hood. Mansorysays its ventilation channels maximize airflow to the engine. Corresponding bits of carbon fiber can be found on the sides and rear of the car, where a roof and extremely tasteful rear spoiler Mansory X6 M expected to more stability at high speeds, but we guess most of these cars spend more time in more than 100 parking updates made on mph.The Mansory X5 X6 M is like M, but the body combined with standard X6 additional catchy bit of pushing this SUV top.We not more fans alloy wheels too large 23-inch, but it is hard to argue with larger brakes and a multi-piston brake or larger tires. A new exhaust system and revised engine electronics are responsible for the impetus to the 670th power alleged speed is electronically limited to 186 mph.The Mansory X6 M is wider too.
Inside, a new steering wheel to help customers benefit will be suspended. As explained by Mansory, the rest of the interior is open to the fabric: the cheerful company of changing the combinations of leather upholstery, Alcantara, wood, steel or aluminum finishes - just bring your checkbook
Huge front air intakes make an impression but we know you’re focusing on that carbon-fiber hood. Mansorysays its ventilation channels optimize air flow to the engine. Matching bits of carbon-fiber can be found on the sides and the rear of the car, where a roof and extremely tasteful rear lip spoiler supposedly give the Mansory X6 M more stability at high speeds, but we’re guessing most of these cars will spend more time in valet parking than at over 100 mph.The upgrades performed on the X6 M are similar to Mansory’s X5 M, but the X6’s standard bodystyle combined with added eye-catching bits push this SUV over the top.We aren’t fans of the too-large 23-inch light alloy wheels, but it’s hard to argue with larger brakes and a multi-piston brake system or the fatter tires. A new exhaust system and revised engine electronics are responsible for the horsepower boost to a claimed 670. Top speed is electronically limited to 186 mph.The Mansory X6 M is wider too. Inside, a new steering wheel helps customers make the most of the retuned suspension. As Mansory explains, the rest of the interior is an open canvas: the company will be happy to customize an interior with combinations of leather, Alcantara, wood, carbon, or aluminum trim — just bring your checkbook
Large front air intakes to impress, but we know that you focus on the carbon fiber hood. Mansorysays its ventilation channels maximize airflow to the engine. Corresponding bits of carbon fiber can be found on the sides and rear of the car, where a roof and extremely tasteful rear spoiler Mansory X6 M expected to more stability at high speeds, but we guess most of these cars spend more time in more than 100 parking updates made on mph.The Mansory X5 X6 M is like M, but the body combined with standard X6 additional catchy bit of pushing this SUV top.We not more fans alloy wheels too large 23-inch, but it is hard to argue with larger brakes and a multi-piston brake or larger tires. A new exhaust system and revised engine electronics are responsible for the impetus to the 670th power alleged speed is electronically limited to 186 mph.The Mansory X6 M is wider too.
Inside, a new steering wheel to help customers benefit will be suspended. As explained by Mansory, the rest of the interior is open to the fabric: the cheerful company of changing the combinations of leather upholstery, Alcantara, wood, steel or aluminum finishes - just bring your checkbook
Huge front air intakes make an impression but we know you’re focusing on that carbon-fiber hood. Mansorysays its ventilation channels optimize air flow to the engine. Matching bits of carbon-fiber can be found on the sides and the rear of the car, where a roof and extremely tasteful rear lip spoiler supposedly give the Mansory X6 M more stability at high speeds, but we’re guessing most of these cars will spend more time in valet parking than at over 100 mph.The upgrades performed on the X6 M are similar to Mansory’s X5 M, but the X6’s standard bodystyle combined with added eye-catching bits push this SUV over the top.We aren’t fans of the too-large 23-inch light alloy wheels, but it’s hard to argue with larger brakes and a multi-piston brake system or the fatter tires. A new exhaust system and revised engine electronics are responsible for the horsepower boost to a claimed 670. Top speed is electronically limited to 186 mph.The Mansory X6 M is wider too. Inside, a new steering wheel helps customers make the most of the retuned suspension. As Mansory explains, the rest of the interior is an open canvas: the company will be happy to customize an interior with combinations of leather, Alcantara, wood, carbon, or aluminum trim — just bring your checkbook
Huge front air intakes make an impression but we know you’re focusing on that carbon-fiber hood. Mansory says its ventilation channels optimize air flow to the engine. Matching bits of carbon-fiber can be found on the sides and the rear of the car, where a roof and extremely tasteful rear lip spoiler supposedly give the Mansory X6 M more stability at high speeds, but we’re guessing most of these cars will spend more time in valet parking than at over 100 mph.
The upgrades performed on the X6 M are similar to Mansory’s X5 M, but the X6′s standard bodystyle combined with added eye-catching bits push this SUV over the top.
We aren’t fans of the too-large 23-inch light alloy wheels, but it’s hard to argue with larger brakes and a multi-piston brake system or the fatter tires. A new exhaust system and revised engine electronics are responsible for the horsepower boost to a claimed 670. Top speed is electronically limited to 186 mph.
The Mansory X6 M is wider too. Inside, a new steering wheel helps customers make the most of the retuned suspension. As Mansory explains, the rest of the interior is an open canvas: the company will be happy to customize an interior with combinations of leather, Alcantara, wood, carbon, or aluminum trim — just bring your checkbook and imagination.
A diesel engine (also known as a compression-ignition engine) is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber. This is in contrast to spark-ignition engines such as a petrol engine (gasoline engine) or gas engine (using a gaseous fuel as opposed to gasoline), which uses a spark plug to ignite an air-fuel mixture. The engine was developed by Rudolf Diesel in 1893.
The diesel engine has the highest thermal efficiency of any regular internal or external combustion engine due to its very high compression ratio. Low-speed Diesel engines (as used in ships and other applications where overall engine weight is relatively unimportant) often have a thermal efficiency which exceeds 50 percent.[1][2]
Diesel engines are manufactured in two stroke and four stroke versions. They were originally used as a more efficient replacement for stationary steam engines. Since the 1910s they have been used in submarines and ships. Use in locomotives, trucks and electric generating plants followed later. In the 1930s, they slowly began to be used in a few automobiles. Since the 1970s, the use of diesel engines in larger on-road and off-road vehicles in the USA increased. As of 2007, about 50 percent of all new car sales in Europe are diesel.[3]
The world's largest diesel engine is currently a Wärtsilä Sulzer RT96-C Common Rail marine diesel of about 108,920 hp (81,220 kW) @ 102 rpm[4] output.[5]
was born in Paris in 1858 into a family of German expatriates.[6] He was educated at Munich Polytechnic. After graduation he was employed as a refrigerator engineer, but his true love lay in engine design. Diesel designed many heat engines, including a solar-powered air engine. In 1892 he received patents in Germany, Switzerland, the United Kingdom and filed in the United States for "Method of and Apparatus for Converting Heat into Work".[7] In 1893 he described a "slow-combustion engine" that first compressed air thereby raising its temperature above the igniting-point of the fuel, then gradually introducing fuel while letting the mixture expand "against resistance sufficiently to prevent an essential increase of temperature and pressure", then cutting off fuel and "expanding without transfer of heat".[citation needed] In 1894 and 1895 he filed patents and addenda in various countries for his Diesel engine; the first patents were issued in Spain (No.16,654), France (No.243,531) and Belgium (No.113,139) in December 1894, and in Germany (No.86,633) in 1895 and the United States (No.608,845) in 1898.[8] He operated his first successful engine in 1897. His engine was the first[citation needed] to prove that fuel could be ignited solely with high compression.
Though best known for his invention of the pressure-ignited heat engine that bears his name, Rudolf Diesel was also a well-respected thermal engineer and a social theorist. Diesel's inventions have three points in common: they relate to heat transfer by natural physical processes or laws; they involve markedly creative mechanical design; and they were initially motivated by the inventor's concept of sociological needs. Rudolf Diesel originally conceived the diesel engine to enable independent craftsmen and artisans to compete with industry.[9]
At Augsburg, on August 10, 1893, Rudolf Diesel's prime model, a single 10-foot (3.0 m) iron cylinder with a flywheel at its base, ran on its own power for the first time. Diesel spent two more years making improvements and in 1896 demonstrated another model with a theoretical efficiency of 75 percent, in contrast to the 10 percent efficiency of the steam engine. By 1898, Diesel had become a millionaire. His engines were used to power pipelines, electric and water plants, automobiles and trucks, and marine craft. They were soon to be used in mines, oil fields, factories, and transoceanic shipping.
The diesel internal combustion engine differs from the gasoline powered Otto cycle by using highly compressed hot air to ignite the fuel rather than using a spark plug (compression ignition rather than spark ignition).
In the true diesel engine, only air is initially introduced into the combustion chamber. The air is then compressed with a compression ratio typically between 15:1 and 22:1 resulting in 40-bar (4.0 MPa; 580 psi) pressure compared to 8 to 14 bars (0.80 to 1.4 MPa) (about 200 psi) in the petrol engine. This high compression heats the air to 550 °C (1,022 °F). At about the top of the compression stroke, fuel is injected directly into the compressed air in the combustion chamber. This may be into a (typically toroidal) void in the top of the piston or a pre-chamber depending upon the design of the engine. The fuel injector ensures that the fuel is broken down into small droplets, and that the fuel is distributed evenly. The heat of the compressed air vaporizes fuel from the surface of the droplets. The vapour is then ignited by the heat from the compressed air in the combustion chamber, the droplets continue to vaporise from their surfaces and burn, getting smaller, until all the fuel in the droplets has been burnt. The start of vaporisation causes a delay period during ignition and the characteristic diesel knocking sound as the vapor reaches ignition temperature and causes an abrupt increase in pressure above the piston. The rapid expansion of combustion gases then drives the piston downward, supplying power to the crankshaft.[23] Engines for scale-model aeroplanes use a variant of the Diesel principle but premix fuel and air via a carburation system external to the combustion chambers.
As well as the high level of compression allowing combustion to take place without a separate ignition system, a high compression ratio greatly increases the engine's efficiency. Increasing the compression ratio in a spark-ignition engine where fuel and air are mixed before entry to the cylinder is limited by the need to prevent damaging pre-ignition. Since only air is compressed in a diesel engine, and fuel is not introduced into the cylinder until shortly before top dead centre (TDC), premature detonation is not an issue and compression ratios are much higher.
Diesel's original engine injected fuel with the assistance of compressed air, which atomized the fuel and forced it into the engine through a nozzle (a similar principle to an aerosol spray). The nozzle opening was closed by a pin valve lifted by the camshaft to initiate the fuel injection before top dead centre (TDC). This is called an air-blast injection. Driving the three stage compressor used some power but the efficiency and net power output was more than any other combustion engine at that time.
Diesel engines in service today raise the fuel to extreme pressures by mechanical pumps and deliver it to the combustion chamber by pressure-activated injectors without compressed air. With direct injected diesels, injectors spray fuel through 4 to 12 small orifices in its nozzle. The early air injection diesels always had a superior combustion without the sharp increase in pressure during combustion. Research is now being performed and patents are being taken out to again use some form of air injection to reduce the nitrogen oxides and pollution, reverting to Diesel's original implementation with its superior combustion and possibly quieter operation. In all major aspects, the modern diesel engine holds true to Rudolf Diesel's original design, that of igniting fuel by compression at an extremely high pressure within the cylinder. With much higher pressures and high technology injectors, present-day diesel engines use the so-called solid injection system applied by Herbert Akroyd Stuart for his hot bulb engine. The indirect injection engine could be considered the latest development of these low speed hot bulb ignition engines
A vital component of all diesel engines is a mechanical or electronic governor which regulates the idling speed and maximum speed of the engine by controlling the rate of fuel delivery. Unlike Otto-cycle engines, incoming air is not throttled and a diesel engine without a governor cannot have a stable idling speed and can easily overspeed, resulting in its destruction. Mechanically governed fuel injection systems are driven by the engine's gear train.[24] These systems use a combination of springs and weights to control fuel delivery relative to both load and speed.[24] Modern electronically controlled diesel engines control fuel delivery by use of an electronic control module (ECM) or electronic control unit (ECU). The ECM/ECU receives an engine speed signal, as well as other operating parameters such as intake manifold pressure and fuel temperature, from a sensor and controls the amount of fuel and start of injection timing through actuators to maximise power and efficiency and minimise emissions. Controlling the timing of the start of injection of fuel into the cylinder is a key to minimizing emissions, and maximizing fuel economy (efficiency), of the engine. The timing is measured in degrees of crank angle of the piston before top dead centre. For example, if the ECM/ECU initiates fuel injection when the piston is 10 degrees before TDC, the start of injection, or timing, is said to be 10° BTDC. Optimal timing will depend on the engine design as well as its speed and load.
Advancing the start of injection (injecting before the piston reaches to its SOI-TDC) results in higher in-cylinder pressure and temperature, and higher efficiency, but also results in elevated engine noise and increased oxides of nitrogen (NOx) emissions due to higher combustion temperatures. Delaying start of injection causes incomplete combustion, reduced fuel efficiency and an increase in exhaust smoke, containing a considerable amount of particulate matter and unburned
Many configurations of fuel injection have been used over the past century (1901–2000).
Most present day (2008) diesel engines make use of a camshaft, rotating at half crankshaft speed, lifted mechanical single plunger high pressure fuel pump driven by the engine crankshaft. For each cylinder, its plunger measures the amount of fuel and determines the timing of each injection. These engines use injectors that are very precise spring-loaded valves that open and close at a specific fuel pressure. For each cylinder a plunger pump is connected to an injector with a high pressure fuel line. Fuel volume for each single combustion is controlled by a slanted groove in the plunger which rotates only a few degrees releasing the pressure and is controlled by a mechanical governor, consisting of weights rotating at engine speed constrained by springs and a lever. The injectors are held open by the fuel pressure. On high speed engines the plunger pumps are together in one unit.[32] Each fuel line should have the same length to obtain the same pressure delay.
A cheaper configuration on high speed engines with fewer than six cylinders is to use an axial-piston distributor pump, consisting of one rotating pump plunger delivering fuel to a valve and line for each cylinder (functionally analogous to points and distributor cap on an Otto engine).[24] This contrasts with the more modern method of having a single fuel pump which supplies fuel constantly at high pressure with a common rail (single fuel line common) to each injector. Each injector has a solenoid operated by an electronic control unit, resulting in more accurate control of injector opening times that depend on other control conditions, such as engine speed and loading, and providing better engine performance and fuel economy. This design is also mechanically simpler than the combined pump and valve design, making it generally more reliable, and less loud, than its mechanical counterpart.
Both mechanical and electronic injection systems can be used in either direct or indirect injection configurations.
Older diesel engines with mechanical injection pumps could be inadvertently run in reverse, albeit very inefficiently, as witnessed by massive amounts of soot being ejected from the air intake. This was often a consequence of push starting a vehicle using the wrong gear. Large ship diesels can run either way.
Huge front-air-intakes-make-impression
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