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  ディーゼル は、同名のファッションブランドを展開するイタリアのアパレルメーカー。略称:DSL。年にレンツォ・ロッソによって創立され、イタリア北東部の都市モルヴェーナに拠点を置く。 創業者のレンツォ・ロッソが代表を務めるオンリー・ザ・ブレイブ社の系列にある。 イタリアのプレミアム・カジュアル・ブランドDIESEL(ディーゼル)の公式オンラインストアです。メンズ・ウィメンズ・キッズのデニム、ウェア、バッグなど幅広い  


Diesel -



 

The diesel engine , named after Rudolf Diesel , is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-called compression-ignition engine CI engine.

This contrasts with engines using spark plug -ignition of the air-fuel mixture, such as a petrol engine gasoline engine or a gas engine using a gaseous fuel like natural gas or liquefied petroleum gas.

Diesel engines work by compressing only air, or air plus residual combustion gases from the exhaust known as exhaust gas recirculation EGR. Air is inducted into the chamber during the intake stroke, and compressed during the compression stroke. This increases the air temperature inside the cylinder to such a high degree that atomised diesel fuel injected into the combustion chamber ignites.

With the fuel being injected into the air just before combustion, the dispersion of the fuel is uneven; this is called a heterogeneous air-fuel mixture. 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.

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 s, they have been used in submarines and ships. Use in locomotives, buses, trucks, heavy equipment , agricultural equipment and electricity generation plants followed later. In the s, they slowly began to be used in a few automobiles.

Since the s, the use of diesel engines in larger on-road and off-road vehicles in the US has increased. According to Konrad Reif , the EU average for diesel cars at the time accounted for half of newly registered cars. The world's largest diesel engines put in service are cylinder, two-stroke marine diesel engines; they produce a peak power of almost MW each. In , Rudolf Diesel , who was a student at the "Polytechnikum" in Munich , attended the lectures of Carl von Linde.

According to Diesel, this ignited the idea of creating a highly efficient engine that could work on the Carnot cycle. Diesel was heavily criticised for his essay, but only few found the mistake that he made; [10] his rational heat motor was supposed to utilise a constant temperature cycle with isothermal compression that would require a much higher level of compression than that needed for compression ignition.

Diesel's idea was to compress the air so tightly that the temperature of the air would exceed that of combustion. However, such an engine could never perform any usable work. By June , Diesel had realised his original cycle would not work and he adopted the constant pressure cycle. Notice that there is no longer a mention of compression temperatures exceeding the temperature of combustion. Now it is simply stated that the compression must be sufficient to trigger ignition.

In , Diesel received patents in Germany , Switzerland , the United Kingdom and the United States for "Method of and Apparatus for Converting Heat into Work".

Diesel was attacked and criticised over a time period of several years. Critics claimed that Diesel never invented a new motor and that the invention of the diesel engine is fraud. His claims were unfounded and he lost a patent lawsuit against Diesel.

Diesel sought out firms and factories that would build his engine. On 10 August , the first ignition took place, the fuel used was petrol. Brayton , [26] albeit that Diesel substantially improved the system. Between 8 November and 20 December , the second prototype had successfully covered over hours on the test bench. In the January report, this was considered a success. In February , Diesel considered supercharging the third prototype. During summer that year the engine was built, it was completed on 6 October The engine was rated The characteristics of a diesel engine are [].

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 diesel engine, only air is initially introduced into the combustion chamber. The air is then compressed with a compression ratio typically between and This high compression causes the temperature of the air to rise.

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 vaporises 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. Combustion occurs at a substantially constant pressure during the initial part of the power stroke. The start of vaporisation causes a delay before ignition and the characteristic diesel knocking sound as the vapour reaches ignition temperature and causes an abrupt increase in pressure above the piston not shown on the P-V indicator diagram.

When combustion is complete the combustion gases expand as the piston descends further; the high pressure in the cylinder drives the piston downward, supplying power to the crankshaft. 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 pre-ignition , which would cause engine damage. 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 a problem and compression ratios are much higher. The p—V diagram is a simplified and idealised representation of the events involved in a diesel engine cycle, arranged to illustrate the similarity with a Carnot cycle.

Starting at 1, the piston is at bottom dead centre and both valves are closed at the start of the compression stroke; the cylinder contains air at atmospheric pressure. Between 1 and 2 the air is compressed adiabatically — that is without heat transfer to or from the environment — by the rising piston. This is only approximately true since there will be some heat exchange with the cylinder walls. During this compression, the volume is reduced, the pressure and temperature both rise.

At or slightly before 2 TDC fuel is injected and burns in the compressed hot air. Chemical energy is released and this constitutes an injection of thermal energy heat into the compressed gas. Combustion and heating occur between 2 and 3. In this interval the pressure remains constant since the piston descends, and the volume increases; the temperature rises as a consequence of the energy of combustion. At 3 fuel injection and combustion are complete, and the cylinder contains gas at a higher temperature than at 2.

Between 3 and 4 this hot gas expands, again approximately adiabatically. Work is done on the system to which the engine is connected. During this expansion phase the volume of the gas rises, and its temperature and pressure both fall. At 4 the exhaust valve opens, and the pressure falls abruptly to atmospheric approximately. This is unresisted expansion and no useful work is done by it.

Ideally the adiabatic expansion should continue, extending the line 3—4 to the right until the pressure falls to that of the surrounding air, but the loss of efficiency caused by this unresisted expansion is justified by the practical difficulties involved in recovering it the engine would have to be much larger.

After the opening of the exhaust valve, the exhaust stroke follows, but this and the following induction stroke are not shown on the diagram. If shown, they would be represented by a low-pressure loop at the bottom of the diagram. At 1 it is assumed that the exhaust and induction strokes have been completed, and the cylinder is again filled with air. The piston-cylinder system absorbs energy between 1 and 2 — this is the work needed to compress the air in the cylinder, and is provided by mechanical kinetic energy stored in the flywheel of the engine.

Work output is done by the piston-cylinder combination between 2 and 4. The difference between these two increments of work is the indicated work output per cycle, and is represented by the area enclosed by the p—V loop. The adiabatic expansion is in a higher pressure range than that of the compression because the gas in the cylinder is hotter during expansion than during compression. It is for this reason that the loop has a finite area, and the net output of work during a cycle is positive.

throttle valves. Diesel engines are combustion engines and, therefore, emit combustion products in their exhaust gas. Due to incomplete combustion, [] diesel engine exhaust gases include carbon monoxide , hydrocarbons , particulate matter , and nitrogen oxides pollutants. About 90 per cent of the pollutants can be removed from the exhaust gas using exhaust gas treatment technology. The particulate matter in diesel exhaust emissions is sometimes classified as a carcinogen or "probable carcinogen" and is known to increase the risk of heart and respiratory diseases.

In principle, a diesel engine does not require any sort of electrical system. However, most modern diesel engines are equipped with an electrical fuel pump, and an electronic engine control unit.

However, there is no high-voltage electrical ignition system present in a diesel engine. This eliminates a source of radio frequency emissions which can interfere with navigation and communication equipment , which is why only diesel-powered vehicles are allowed in some parts of the American National Radio Quiet Zone. To control the torque output at any given time i. when the driver of a car adjusts the accelerator pedal , a governor adjusts the amount of fuel injected into the engine.

Mechanical governors have been used in the past, however electronic governors are more common on modern engines. Mechanical governors are usually driven by the engine's accessory belt or a gear-drive system [] [] and use a combination of springs and weights to control fuel delivery relative to both load and speed.

Due to the amount of air being constant for a given RPM while the amount of fuel varies, very high "lean" air-fuel ratios are used in situations where minimal torque output is required. This differs from a petrol engine, where a throttle is used to also reduce the amount of intake air as part of regulating the engine's torque output. Controlling the timing of the start of injection of fuel into the cylinder is similar to controlling the ignition timing in a petrol engine.

It is therefore a key factor in controlling the power output, fuel consumption and exhaust emissions. There are several different ways of categorising diesel engines, as outlined in the following sections. High-speed engines are used to power trucks lorries , buses , tractors , cars , yachts , compressors , pumps and small electrical generators.

Many modern engines, particularly in on-highway applications, have common rail direct injection. Medium-speed engines are used in large electrical generators, railway diesel locomotives , ship propulsion and mechanical drive applications such as large compressors or pumps.

Medium speed diesel engines operate on either diesel fuel or heavy fuel oil by direct injection in the same manner as low-speed engines. Usually, they are four-stroke engines with trunk pistons; [] a notable exception being the EMD , , and engines, which are all two-stroke. The power output of medium-speed diesel engines can be as high as 21, kW, [] with the effective efficiency being around

   


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