Diesel particulate filter

A diesel particulate filter (DPF) is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine. A diesel particulate filter (top left) in a Peugeot Off-road - DPF Installation Mode of action Wall-flow diesel particulate filters usually remove 85% or more of the soot, and under certain conditions can attain soot removal efficiencies approaching 100%. Some filters are single-use, intended for disposal and replacement once full of accumulated ash. Others are designed to burn off the accumulated particulate either passively through the use of a catalyst or by active means such as a fuel burner which heats the filter to soot combustion temperatures. This is accomplished by engine programming to run (when the filter is full) in a manner that elevates exhaust temperature, in conjunction with an extra fuel injector in the exhaust stream that injects fuel to react with a catalyst element to burn off accumulated soot in the DPF filter, or through other methods. This is known as "filter regeneration". Cleaning is also required as part of periodic maintenance, and it must be done carefully to avoid damaging the filter. Failure of fuel injectors or turbochargers resulting in contamination of the filter with raw diesel or engine oil can also necessitate cleaning. The regeneration process occurs at road speeds higher than can generally be attained on city streets; vehicles driven exclusively at low speeds in urban traffic can require periodic trips at higher speeds to clean out the DPF. If the driver ignores the warning light and waits too long to operate the vehicle above 40 miles per hour (64 km/h), the DPF may not regenerate properly, and continued operation past that point may spoil the DPF completely so it must be replaced. Some newer diesel engines, namely those installed in combination vehicles, can also perform what is called a Parked Regeneration, where the engine increases RPM to around 1400 while parked, to increase the temperature of the exhaust. Diesel engines produce a variety of particles during combustion of the fuel/air mix due to incomplete combustion. The composition of the particles varies widely dependent upon engine type, age, and the emissions specification that the engine was designed to meet. Two-stroke diesel engines produce more particulate per unit of power than do four-stroke diesel engines, as they burn the fuel-air mix less completely. Diesel particulate matter resulting from the incomplete combustion of diesel fuel produces soot (black carbon) particles. These particles include tiny nanoparticles—smaller than a thousandth of a millimeter (one micron). Soot and other particles from diesel engines worsen the particulate matter pollution in the air...

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Turbo-diesel

Turbo-diesel, also written as turbodiesel and turbo diesel, refers to any diesel engine equipped with a turbocharger. Turbocharging is common in modern car and truck diesel engines to produce higher power outputs, lower emissions levels, and improved efficiency from a similar capacity of engine. Turbo-diesels in automobiles offer a higher refinement level than their naturally aspirated counterparts. A diesel engine turbocharger History The turbocharger was invented in the early 20th century by Alfred Büchi, a Swiss engineer and the head of diesel engine research at Gebruder Sulzer engine manufacturing company in Winterthur. Büchi specifically intended his device to be used on diesel engines. His patent of 1905 noted the efficiency improvements that a turbocharger could bring to diesel engines  which in 1922 had first been developed for use in road transportation. At the time, metal and bearing technology was not sufficiently advanced to allow a practical turbocharger to be built. The first practical turbodiesels were marine engines fitted to two German passenger liners - the Danzig and the Preussen in 1923, each having two 10-cylinder engines of 2,500 horsepower (the naturally aspirated version of the same engine produced 1,750 HP). By the late 1920s, several diesel engine builders were making large turbodiesels for marine and stationary use, such as Sulzer Bros., MAN, Daimler-Benz, and Paxman. Turbocharger technology was improved greatly by developments during World War II and subsequent development of the gas turbine. It was now possible to use smaller turbochargers on smaller, higher-speed engines. Diesel locomotives with turbodiesels began appearing in the late 1940s and 1950s. In 1951 MAN presented a turbocharged version of their MK26 truck, although it was never put into mass production. Series production of turbocharged diesel trucks commenced in 1954, when both MAN 750TL1 and Volvo Titan Turbo were introduced to the markets. The building of the Interstate Highway System in the USA from 1956 made long-distance road transportation of goods more attractive. To keep up with general traffic, more powerful engines came in increasing demand. Cummins, Detroit, and CAT all had turbo-charging as an option by the late-1960s. In Europe, legislation was introduced in Germany mandating a minimum power-to-weight ratio for trucks; by the late 1960s, a 38-tonne consist had to have at least 304 hp. Most manufacturers met these requirement with large-displacement natural aspiration engines, some with the option of large-displacement or turbo-charging, while Scania and Volvo where among those that only provided turbocharged trucks that met the demands. Turbo-charging was not preferred initially as the engines were perceived to be less reliable, however the method won a decisive victory by the mid-1970s as the 1973 oil crisis increased fuel costs. The last market to see the absolute penetration of turbo diesels was Japan, where legislation on particle emissions effectively mandated natural aspiration engines until effective particle filters...

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Diesel engine

The diesel engine (also known as a compression-ignition or CI engine), named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel which is injected into the combustion chamber is caused by the elevated temperature of the air in the cylinder due to mechanical compression (adiabatic compression). Diesel engines work by compressing only the air. This increases the air temperature inside the cylinder to such a high degree that atomised diesel fuel that is injected into the combustion chamber ignites spontaneously. This contrasts with spark-ignition engines such as a petrol engine (gasoline engine) or gas engine (using a gaseous fuel as opposed to petrol), which use a spark plug to ignite an air-fuel mixture. In diesel engines, glow plugs (combustion chamber pre-warmers) may be used to aid starting in cold weather, or when the engine uses a lower compression-ratio, or both. The original diesel engine operates on the "constant pressure" cycle of gradual combustion and produces no audible knock. A diesel engine built by MAN AG in 1906   Detroit Diesel timing Fairbanks Morse model 32 The diesel engine has the highest thermal efficiency (engine efficiency) of any practical internal or external combustion engine due to its very high expansion ratio and inherent lean burn which enables heat dissipation by the excess air. A small efficiency loss is also avoided compared to two-stroke non-direct-injection gasoline engines since unburned fuel is not present at valve overlap and therefore no fuel goes directly from the intake/injection to the exhaust. Low-speed diesel engines (as used in ships and other applications where overall engine weight is relatively unimportant) can have a thermal efficiency that exceeds 50%. Diesel engines may be designed as either two-stroke or four-stroke cycles. 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, heavy equipment and electricity generation 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 US increased. According to the British Society of Motor Manufacturing and Traders, the EU average for diesel cars accounts for 50% of the total sold, including 70% in France and 38% in the UK. The world's largest diesel engine put in service in 2006 is currently a Wärtsilä-Sulzer RTA96-C Common Rail marine diesel, which produces a peak power output of 84.42 MW (113,210 hp) at 102 rpm. History Diesel's prototype engine Diesel's first experimental engine 1893 Hot bulb engine The definition of a "Diesel" engine to many has become an engine that uses compression ignition. To some it may be an engine that uses heavy fuel oil. To others an engine that does not use spark ignition....

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