Что такое разнос дизельного двигателя: Что такое разнос дизельного двигателя?

Дизельный двигатель, разнос мотора, неисправность

В настоящее время все шире используются дизельные автомобили. Их применяют как для перевозки различных грузов, так и используют в качестве пассажирского транспорта. Многие автолюбители в связи с ухудшением состояния дорожного полотна предпочитают пересесть на дизельные внедорожники.

Существует ряд преимуществ, по которым дизельный двигатель существенно выигрывает по сравнению с бензиновым. К таковым относятся:

• Более долгий срок эксплуатации;
• Существенная экономия денежных средств на топливе;
• По сравнению с бензиновым мотором значительно ниже нагрузка на окружающую среду;
• Нет необходимости проводить частую регулировку двигателя. Однако нужно тщательно следить за состоянием воздушного фильтра, а также проверять угол, под которым происходит впрыск топлива.

Что такое разнос двигателя?

Количество дизельного транспорта с каждым днем все увеличивается. Поэтому достаточно часто можно наблюдать картину идущий автомобиль в клубах черного дыма. Или из выхлопной трубы легкового автомобиля вылетает едкий дым с достаточно громкими хлопками. В отдельных случаях наблюдаются вспышки пламени. Это является первым признаком проблемы, которую называют, разнос дизельного двигателя.

Разнос двигателя — это повышение оборотов двигателя до критических значений. Данное событие для водителя неподконтрольно. Опасность проявляется во время движения, так как разгон или торможение может спровоцировать аварию.

Даже если эксплуатировать машину в спокойном режиме, повышенные обороты способны полностью вывести из строя мотор. На панели приборов стрелка тахометра будет располагаться в зоне, отмеченной красным.

К последствиям разноса двигателя можно отнести следующие проблемы:

• Поломка коленчатого вала;
• Начинается процесс плавления клапанов и поршней;
• Возможен взрыв двигателя, при котором осколки разлетятся по всем системам автомобиля, расположенным под капотом.

Причина разноса

Существует две причины разноса двигателя:

1. Основная причина разноса дизельного мотора — это неконтролируемое, самостоятельное попадание во впускной коллектор жидкостей, которые способны самостоятельно воспламеняться в цилиндрах мотора. Наиболее распространено попадание моторного масла;
2. Неисправность топливного насоса высокого давления. Это распространено на старых автомобилях с механическим управлением. Топливный насос отвечает за подачу топлива в точных дозах. Центробежный регулятор в системе требуется, чтобы мотор соблюдал строго нужные обороты. В случае, если коленчатый вал начинает вращаться чаще, то с помощью регулятора происходит ограничение подачи горючего. При увеличении оборотов, происходит увеличенная подача насосом топлива, которым заливаются цилиндры. В результате начинаются максимальные обороты, и двигатель идет вразнос.

Рассмотрим подробнее, почему же двигатель идет вразнос? В момент попадания инородных жидкостей, когда начался процесс разноса, мотор очень сложно заглушить. Даже если принудительно перекрывать подачу топлива, то масло продолжает идти в мотор, пока он вращается. А вращаться двигатель будет, пока идет подача масла.

То есть замкнутый круг происходит. Разорвать этот круг может только разрушение мотора вследствие критических высоких оборотов, или масляное голодание.

В дизельном моторе, смесь, состоящая из топлива и воздуха, воспламеняется не от случайной искры, а от степени сжатия и высоких температур.

Если вовремя грамотно и правильно не остановить работу оборудования, то это приведет к полному разрушению буквально в течение нескольких минут.

Опасность разноса для дизельных автомобилей

В цилиндрах дизельных моторов давление всегда должно быть постоянным и достаточно высоким. И составлять не менее 20 Бар. Такое давление необходимо для того, чтобы при впрыскивании топлива, оно самовоспламенялось. В случае, если происходит нарушение при подаче воздуха, то работа двигателя останавливается.

Работа дизельного двигателя основана на принципе качественного регулирования, то есть регулировка оборотов выполняется при помощи нормального количества подаваемого топлива, и при высоком качестве самого горючего.

В дизельных автомобилях мотор может уйти в разнос даже при выключенном зажигании, когда форсунками не распыляется горючее даже в минимальных дозах.

Как остановить двигатель?

Как только автовладелец заметил неисправности с двигателем — его необходимо срочно остановить. Как это сделать?

На заводах-производителях дизельного транспорта в системе перед нагнетателями устанавливаются аварийные заслонки. Их предназначение — дать возможность ручного отключения мотора. То есть, если нет возможности прекратить подачу топлива, то требуется установить подачу воздуха.

План действий при нарушении работы двигателя

Многими автомобилистами уже отработан определенный план мероприятий, которые рекомендуется выполнять в случае поломки оборудования.

1. Если обороты мотора почему-то начали резко возрастать, то необходимо отключить зажигание, передачу. Очень часто водитель не всегда успевает вовремя заметить возрастание оборотов. На начальном этапе их роста, существует возможность заглушить двигатель обычным способом.
2. Если есть возможность — переместиться на обочину;
3. При необходимости открыть капот, чтобы получить доступ к воздухоприемнику;
4. Рекомендуется включить аварийные огни;
5. Отверстие воздухозаборника необходимо закрыть плотной тканью. Дальнобойщики используют для этих целей фуфайки. Если в машине есть углекислотный огнетушитель, то применить его. Струя направляется в воздухозаборник. Так как этот газ не горюч, то мощный поток заставит мотор как бы «захлебнуться», что приведет к его остановке;
6. Заводить двигатель больше нельзя. Иначе автовладелец увидит, как умирает его мотор. До ремонтной мастерской машина транспортируется или на буксире, или на эвакуаторе.

Если по каким-то причинам, водитель не может выполнить данные манипуляции, то следует отойти от машины на небольшое расстояние и начинать вызывать специализированные службы в помощь.

Если вовремя выполнить вышеуказанные действия, то это приведет к тому, что потребуется только ремонт двигателя, возможно и замена турбокомпрессора. Однако никаких других серьезных последствий не будет.

Специалисты не рекомендуют выполнять ремонт оборудования своими силами, ведь малейшая недоработка приведет к тому, что ситуация с разносом повторится. Дизельный двигатель лучше всего ремонтировать в специализированных центрах. Поэтому не стоит экономить на работе профессионалов, чтобы не платить дважды.

90000 How do diesel engines work? 90001 90002 90003 90004 90005 90006 90007 90008 90002 by Chris Woodford. Last updated: January 29, 2022. 90003 90011 Have you ever gazed in amazement as a giant truck crawls slowly up a hill? Probably not! Such things happen everyday. But stop and think for a moment about what’s happening-how a huge, heavy load is being systematically lifted against the overwhelming power of gravity using nothing more than a few cups of dirty liquid (fuel, in other words) -and you might agree that what you’re seeing is quite remarkable.Diesel engines are the power behind our biggest machines-trucks, trains, ships, and submarines. On the face of it, they’re similar to ordinary gasoline (petrol) engines but they generate more power, more efficiently by working in a subtly different way. Let’s take a closer look! 90003 90002 Photo: Diesel engines (like the one in this railroad locomotive) are ideal for pulling heavy trains. This is a superbly preserved (and highly polished!) British Rail Class 55 ( «Deltic»), number 55022, called Royal Scots Grey dating from 1960.Here’s a picture of the Napier Deltic diesel engine that powers it. 90003 90015 What is a diesel engine? 90016 90002 90003 90002 Photo: A typical diesel engine (from a fire truck) made by Detroit Diesel Corporation (DDC). Photo by Juan Antoine King courtesy of US Navy. 90003 90002 Like a gasoline engine, a diesel engine is a type of internal combustion engine. Combustion is another word for burning, and internal means inside, so an internal combustion engine is simply one where the fuel is burned inside the main part of the engine (the cylinders) where power is produced.That’s very different from an external combustion engine such as those used by old-fashioned steam locomotives. In a steam engine, there’s a big fire at one end of a boiler that heats water to make steam. The steam flows down long tubes to a cylinder at the opposite end of the boiler where it pushes a piston back and forth to move the wheels. This is external combustion because the fire is outside the cylinder (indeed, typically 6-7 meters or 20-30ft away). In a gasoline or diesel engine, the fuel burns inside the cylinders themselves.Internal combustion wastes much less energy because the heat does not have to flow from where it’s produced into the cylinder: everything happens in the same place. That’s why internal combustion engines are more efficient than external combustion engines (they produce more energy from the same volume of fuel). 90003 90015 How is a diesel engine different from a gasoline engine? 90016 90002 Gasoline engines and diesel engines both work by internal combustion, but in slightly different ways.In a gasoline engine, fuel and air is injected into small metal cylinders. A piston compresses (squeezes) the mixture, making it explosive, and a small electric spark from a sparking plug sets fire to it. That makes the mixture explode, generating power that pushes the piston down the cylinder and (Through the crankshaft and gears) turns the wheels. You can read more about this and watch a simple animation of how it works in our article on car engines. 90003 90002 Diesel engines are similar, but simpler.First, air is allowed into the cylinder and the piston compresses it-but much more than in a gasoline engine. In a gasoline engine, the fuel-air mixture is compressed to about a tenth of its original volume. But in a diesel engine, the air is compressed by anything from 14 to 25 times. If you’ve ever pumped up a bicycle tire, you’ll have felt the pump getting hotter in your hands the longer you used it. That’s because compressing a gas generates heat. Imagine, then, how much heat is generated by forcing air into 14-25 times less space than it normally takes up.So much heat, as it happens, that the air gets really hot-usually at least 500 ° C (1000 ° F) and sometimes very much hotter. Once the air is compressed, a mist of fuel is sprayed into the cylinder typically (in a modern engine) by an electronic fuel-injection system, which works a bit like a sophisticated aerosol can. (The amount of fuel injected varies, depending on how much power the driver wants the engine to produce.) The air is so hot that the fuel instantly ignites and explodes without any need for a spark plug.This controlled explosion makes the piston push back out of the cylinder, producing the power that drives the vehicle or machine in which the engine is mounted. When the piston goes back into the cylinder, the exhaust gases are pushed out through an exhaust valve and, the process repeats itself-hundreds or thousands of times a minute! 90003 90015 How does a diesel engine turn fuel into power? 90016 90002 90003 90002 Animation: How a four-stroke diesel engine works. 90003 90035 Four-stroke engines 90036 90002 Like a gasoline engine, a diesel engine usually operates by repeating a cycle of four stages or strokes, during which the piston moves up and down 90038 twice 90039 (the crankshaft rotates twice in other words) during the cycle.90003 90041 90006 90043 Intake 90044: Air (light blue) is drawn into the cylinder through the open green air inlet valve on the right as the piston moves down. 90007 90006 90043 Compression 90044: The inlet valve closes, the piston moves up, and compresses the air mixture, heating it up. Fuel (dark blue) is injected into the hot gas through the central fuel injection valve and spontaneously ignites. Unlike with a gas engine, no sparking plug is needed to make this happen. 90007 90006 90043 Power 90044: As the air-fuel mixture ignites and burns, it pushes the piston down, driving the crankshaft (Red wheel at bottom) that sends power to the wheels.90007 90006 90043 Exhaust 90044: The green outlet valve on the left opens to let out the exhaust gases, pushed out by the returning piston. 90007 90058 90035 Two-stroke engines 90036 90002 In a two-stroke diesel, the complete cycle happens as the piston moves up and down just 90038 once 90039. Confusingly, there are really three stages in a two-stroke cycle: 90003 90041 90006 90043 Exhaust and intake 90044: Fresh air is blown into the side of the cylinder, pushing the old exhaust out through valves at the top.90007 90006 90043 Compression 90044: The inlet and exhaust valves close. The piston moves up, compresses the air, and heats it up. When the piston reaches the top of the cylinder, fuel is injected and spontaneously ignites. 90007 90006 90043 Power 90044: As the air-fuel mixture ignites, it pushes the piston down, driving the crankshaft that sends power to the wheels. 90007 90058 90002 Two-stroke engines are smaller and lighter than four-stroke ones, and tend to be more efficient since they produce power once during each rotation (instead of once during every two rotations, as in a four-stroke engine).This means they need more cooling and lubrication and suffer higher wear and tear. 90003 90015 What makes a diesel engine more efficient? 90016 90002 Diesel engines are up to twice as efficient as gasoline engines-around 40 percent efficient, that is. In simple terms, that means you can go much further on the same amount of fuel (Or get more miles for your money). There are several reasons for this. First, they compress more and operate at higher temperatures. A fundamental theory of how heat engines work, known as Carnot’s rule, tells us that the efficiency of an engine depends on the high and low temperatures between which it operates.A Diesel engine that cycles through a bigger temperature difference (A higher hottest temperature or a lowest colder temperature) is more efficient. Second, the lack of a sparking-plug ignition system makes for a simpler design that can easily compress the air much more-and this makes the fuel burn hotter and more completely, releasing more energy. There’s another efficiency saving too. In a gasoline engine that’s not working at full power, you need to supply more fuel (or less air) to the cylinder to keep it working; diesel engines do not have that problem so they need less fuel when they’re working at lower power.Another important factor is that diesel fuel carries slightly more energy per gallon than gasoline because the molecules it’s made from have more energy locking their atoms together (in other words, diesel has a higher energy density than gasoline). Diesel is also a better lubricant than gasoline so a diesel engine will naturally run with less friction. 90003 90015 How is diesel fuel different? 90016 90002 Diesel and gasoline are quite different. You’ll know this much if you’ve ever heard the horror stories of people who’ve filled up their car or truck with the wrong sort of fuel! Essentially, diesel is a lower-grade, less-refined product of petroleum made from heavier hydrocarbons (molecules built from more carbon and hydrogen atoms).Crude diesel engines that lack sophisticated fuel injection systems can, in theory, run on almost any hydrocarbon fuel-hence the popularity of biodiesel (a type of biofuel made from, among other things, waste vegetable oil). The inventor of the diesel engine, Rudolf Diesel, successfully ran his early engines on peanut oil and thought his engine would do people a favor by freeing them from a dependency on fuels like coal and gasoline. If only he’d known! 90003 90002 90003 90002 Photo: Have grease will travel: Joshua and Kaia Tickell, a couple of environmentalists, use this trailer (the Green Grease Machine) to make biodiesel fuel for their van (attached to the front) using waste cooking oil thrown out by fast food restaurants.The fuel costs an impressive $ 0.80 per gallon. Photo by Warren Gretz courtesy of US Department of Energy / National Renewable Energy Laboratory (DOE / NREL). 90003 90015 Advantages and disadvantages of diesel engines 90016 90002 Diesels are the most versatile fuel-burning engines in common use today, found in everything from trains and cranes to bulldozers and submarines. Compared to gasoline engines, they’re simpler, more efficient, and more economical. They’re also safer, because diesel fuel is less volatile and its vapor less explosive than gasoline.Unlike gasoline engines, they’re particularly good for moving large loads at low speeds, so they’re ideal for use in freight-hauling ships, trucks, buses, and locomotives. Higher compression means the parts of a diesel engine have to withstand far greater stresses and strains than those in a gasoline engine. That’s why diesel engines need to be stronger and heavier and why, for a long time, they were used only to power large vehicles and machines. While this may seem a drawback, it means diesel engines are typically more robust and last a lot longer than gasoline engines.90003 90002 90003 90002 Photo: Diesel engines are not just used in vehicles: these huge stationary diesel engines generate electricity in a power plant on San Clemente Island. Photo by Warren Gretz courtesy of US Department of Energy / National Renewable Energy Laboratory (DOE / NREL). 90003 90002 Pollution is one of the biggest drawbacks of diesel engines: they’re noisy and they produce a lot of unburned soot particles, which are dirty and hazardous to health. In theory, diesels are more efficient, so they should use less fuel, produce fewer carbon dioxide (CO2) emissions, and contribute less to global warming.In practice, there’s some argument over whether that’s really true. Some laboratory experiments have shown average diesel emissions are only slightly lower than those from gasoline engines, although manufacturers insist that if similar diesel and gasoline cars are compared, the diesels do indeed come out better. Other recent research suggests that even new diesel cars are highly polluting. What about CO2 emissions? According to the British Society of Motor Manufacturers and Traders: «Diesel cars have contributed massively to reducing CO2 emissions.Since 2002 buyers choosing diesel have saved almost 3 million tonnes of CO2 from going into the atmosphere. » Diesel engines do tend to cost more initially than gasoline engines, though their lower running costs and longer operating life generally offsets that. Even so, car buyers no longer seem convinced: there’s been a substantial drop in sales since the Volkswagen emissions scandal in 2015 року, where the German car maker misrepresented emissions of its diesel cars to make them seem less polluting.90003 90002 There’s no question that diesel engines will continue to power heavy vehicles-trucks, buses, ships, and railroad locomotives all depend on them-but their future in cars and lighter vehicles is becoming increasingly uncertain. The push toward electric cars has provided a powerful impetus to make gasoline engines lighter, more economical, and less polluting, and these improved gas engines undermine some of the perceived advantages of using diesels in cars. In the growing competition between affordable electric vehicles and improved gasoline cars, diesels may find themselves squeezed out altogether.Then again, diesels themselves are constantly evolving; in 2011, the US Department of Energy predicted that future engines could rise in efficiency from today’s 40 percent to 60 percent or more. If that happens, diesel could remain a contender in smaller vehicles for many years to come, especially if their sooty emissions can be properly addressed. 90003 90015 Who invented the diesel engine? 90016 90002 90003 90002 Artwork: Rudolf Diesel’s original internal combustion engine, as he drew it in his 1895 patent.The cylinder (1) is at the top. 2) A «plunger» (as Diesel referred to it) is attached by a crank and connecting rod (3) to a flywheel (4). A gear driven by the flywheel (5) is attached to a centrifu 90003.90000 Diesel Engines 90001 Diesel Engines 90002 Hannu Jääskeläinen, Magdi K. Khair 90003 90002 This is a preview of the paper, limited to some initial content. Full access requires DieselNet subscription. 90005 90006 Please log in 90007 to view the complete version of this paper. 90003 90002 90006 Abstract 90007: The diesel engine, invented in the late 19 90012 th 90013 century by Dr. Rudolf Diesel, is the most energy efficient powerplant among all type of internal combustion engines known today.This high efficiency translates to good fuel economy and low greenhouse gas emissions. Other diesel features that have not been matched by competing energy conversion machines include durability, reliability, and fuel safety. The downsides of diesels include noise, low specific power output, NOx and PM emissions, and high cost. 90003 90015 What Is the Diesel Engine? 90016 90002 Most modern diesel engines use the conventional cylinder and piston arrangement operated with a slider crank mechanism common to other internal combustion engines such as the gasoline engine.Considering this basic mechanism, there is very little difference between the basic structure of diesel and gasoline engines. 90003 90002 Conceptually, diesel engines operate by compressing air to high pressure / temperature and then injecting a small amount of fuel into this hot compressed air. The high temperature causes the small amount of highly atomized injected fuel to evaporate. Mixing with the hot surrounding air in the combustion chamber, the evaporated fuel reaches its auto-ignition temperature and burns to release the energy that is stored in that fuel 90020 [391] 90021.90003 90002 The definition of the diesel engine has evolved over the years. For example, in the early 20 90012 th 90013 century, a distinction was made between a «true Diesel Engine» and one that shared some aspects of the diesel cycle but did not encompass all aspects considered to be part of the diesel cycle as then envisioned . One early definition of a «true Diesel Engine» is one having the following features 90020 [2959] 90021: 90003 90029 90030 Compression sufficient to produce the temperature requisite for spontaneous combustion of the fuel.90031 90030 Injection of fuel by a blast of compressed air. 90031 90030 A maximum cycle pressure (attained during combustion) not greatly exceeding the compression pressure, i.e., absence of pronounced explosive effect. 90031 90036 90002 While the first point of the above characteristics is consistent with the modern diesel engine, the last two are not. Over the course of the 1920s and 1930s, the other two characteristics lost their significance. 90003 90002 Solid-type fuel injection started to emerge around 1910 but it was not until the end of the 1920s that it started to rapidly gain acceptance.It is interesting to note that Diesel himself chose air blast injection more out of necessity than choice. Diesel envisioned a solid-injection type of fuel system rather than an air-blast system. 90003 90002 Diesel was quite strict about adhering to constant pressure combustion, item 3. This, however, was only possible in the large relatively slow speed Diesel engines that were common prior to the 1920s. In the smaller high speed engines that emerged in the 1920s, practical considerations meant that combustion was closer to a constant volume process as in the Otto cycle rather the constant pressure as in the Diesel cycle.90003 90002 A brief overview of the early history of the diesel engine is discussed elsewhere. 90003 90002 ### 90003 .90000 Five myths about diesel engines 90001 90002 Argonne mechanical engineer Steve Ciatti takes a crack at some of the more persistent myths surrounding the technology of diesel engines. Credit: Argonne National Laboratory 90003 (PhysOrg.com) — Diesel engines, long confined to trucks and ships, are garnering more interest for their fuel efficiency and reduced carbon dioxide emissions, relative to gasoline engines.Argonne mechanical engineer Steve Ciatti takes a crack at some of the more persistent myths surrounding the technology. 90004 90003 90006 Myth # 1: Diesel is dirty. 90007 90004 90003 «We all have this image of trucks belching out dirty black smoke,» Ciatti said.This smoke is particulate matter from diesel exhaust: soot and small amounts of other chemicals produced by the engine. 90004 90003 But EPA emissions requirements have significantly tightened, and diesel engines now have to meet the same criteria as gasoline engines. They do this by adding a Diesel Particulate Filter (DPF), which removes visible smoke. «DPFs are very effective,» Ciatti said. «They remove 95-plus percent of the mass of smoke.» 90004 90003 The smoke, trapped in a ceramic matrix, accumulates until the car’s computer determines it’s time to clean it out in a process called a «regeneration cycle.»90004 90003 While running, a small amount of extra fuel is added to the combustion chambers in the engine; the resulting heat and oxygen activate a catalyst in the DPF to burn off the accumulated soot. This renders a small fuel consumption penalty. 90004 90003 «Visible smoke is essentially gone, as of the 2007-2010 regulations,» Ciatti said. «If you’re buying a diesel car from 2007 or later, it’s no dirtier than a gasoline-powered vehicle.» 90004 90003 And in the invisible range — diesel engines actually emit less carbon dioxide than gasoline engines do.90004 90003 90006 Myth # 2: Diesel engines will not start in the winter. 90007 90004 90003 «Today’s technologies for cold-start are very effective,» Ciatti said. «Modern diesel engines start in cold weather with very little effort.» 90004 90003 The problem is that diesel jells at low temperatures. Below about 40 ° F, certain hydrocarbons in diesel turn gelatinous. «Since an engine depends on aerosolizing fuel, you do not want goopy fuel,» Ciatti explained. 90004 90003 Often this is remedied with glow plugs, which are heated by the battery and help warm up the fuel so it can vaporize.90004 90003 Low temperatures are not a problem for gasoline engines because gasoline is much more flammable than diesel. Even at room temperature and pressure, gasoline is partly vapor. «Toss a match into a pool of gasoline, and the match will never even hit the surface of the liquid; it will ignite the layer of vapor above the pool,» Ciatti said.»That’s why gasoline has to be handled extremely carefully around any ignition source. Diesel is not so volatile; if you tossed that match into a pool of diesel, it would go out.» 90004 90003 Glow plugs and other remedies, however, effectively vaporize diesel to prepare it for combustion. 90004 90003 90006 Myth # 3: Diesel cars do not perform well. 90007 90004 90003 Because diesel engines are still most common in trucks, many people assume that diesel-powered cars would behave like a truck behaves: slow and sluggish.»But keep in mind, that truck’s likely hauling around 50 tons,» Ciatti said. «In fact, to some degree, some people who drive diesels find they perform better than gasoline engines.» 90004 90003 That’s because diesel-powered engines get their best power when the engine’s revolutions per minute (RPM) are low — that is, at speeds below 65 miles per hour, where most driving takes place. Gasoline engines, in contrast, get to peak power by running the engine very high and fast; a gasoline car only reaches its peak horsepower with the accelerator pedal to the floor and the engine running at 5,000 RPM.90004 90003 «Diesel car performance is far better than the perceived horsepower rating, because you’re getting all that power at speeds where you actually drive the vehicle,» Ciatti said. «You’ve got more pulling power and more acceleration at those speeds.» 90004 90003 90006 Myth # 4: You can not find diesel at the pump. 90007 90004 90003 Diesel-powered pickups and cars are popular enough that the market has taken interest; most neighborhood gas stations now have automotive diesel pumps. 90004 90003 «I drove a diesel car myself for 10 years.I can count on one hand the number of times I had to actually search for a pump, «Ciatti said. 90004 90003 90006 Myth # 5: Diesel fuel is more expensive than gasoline. 90007 90004 90003 Though Chicagoland diesel prices are generally higher than gasoline, in most parts of the country, diesel fuel and gasoline are priced comparably. Today, Illinois taxes diesel at higher rates than gasoline. 90004 90003 «Diesel fuel is not more expensive to produce than gasoline,» Ciatti explained. «Its price usually has to do with the local tax structure.»90004 90003 90006 Bonus: One thing you may not know about diesel! 90007 90004 90003 Diesel engines actually perform better at high altitudes than gasoline engines. 90004 90003 Why? Gasoline engines operate at a very specific ratio of fuel and air. At high altitudes, the air is thinner — literally: there are fewer molecules of air per cubic foot. In the mountains, then, gasoline engines have to add less fuel to keep the ratio perfect, which affects performance. 90004 90003 «But a diesel engine runs fuel-lean; you do not have to keep the ratio perfect,» Ciatti said.Diesel engines have turbochargers, which are pumps driven by exhaust gas. They add more air to the combustion chamber, and more air means more fuel can be added. At altitude, it can pull in more air and more fuel, and thus gets more power than gasoline engines can. Turbochargers do not use extra energy; they run off thermodynamically «free» energy that would be lost as exhaust if not used. 90004 90003 «Drive a diesel at altitude and you’ll see other cars struggling while you zip past,» Ciatti said.»The effect is very noticeable.» 90004 90073 Combining gas and diesel engines could yield best of both worlds 90073 Provided by Argonne National Laboratory 90003 90076 Citation 90077: Five myths about diesel engines (2011, June 14) retrieved 12 July 2020 from https: // phys.org / news / 2011-06-myths-diesel.html 90004 90003 This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. 90004 .90000 MIT School of Engineering | »Which engine is better at high altitude: diesel or gasoline? 90001 90002 Which engine is better at high altitude: diesel or gasoline? 90003 90004 The answer is in the air 90005 90006 By Meg Murphy 90007 90004 This question is the source of heated debate among car aficionados everywhere. 90005 90004 For a clear answer, we went to Wai Cheng, a professor of mechanical engineering and director of the Sloan Automotive Lab (where he does research on engine performance and emissions, combustion science, and energy conversion).90005 90004 «Let’s go a little bit slower and start with a broader question,» Cheng says. «Why do all engines suffer at high altitudes?» The answer is that the air is thinner, meaning it is less dense and there are fewer oxygen molecules to fire the combustion process. «An engine sucks in air. The amount of fuel it can burn is limited by how much air it can suck in. When the air is less dense, the amount of air in the engine cylinder is less — so the power output is less, «he says. 90005 90004 For gasoline engines, you have to open up the throttle wider to achieve the same output at a high altitude.Opening the throttle wider adds more air. The less restrictive throttle lowers the work required to move the air into the cylinder -commonly called «throttle loss.» 90005 90004 Efficiency improves. «For a gasoline engine, the throttle loss is less, which means better fuel efficiency,» Cheng says. But the gasoline engine is not our winner. 90005 90004 Here’s why: a diesel engine is not throttled in the first place. Its efficiency at part load does not significantly change with altitude. Meanwhile, the improvement we see in the gasoline engine’s efficiency is just not big enough to overcome the standard efficiency gap between it and a diesel engine.»Thus, the diesel engine is still more efficient than the gasoline one at high altitude,» says Cheng. 90005 90004 So the next time you’re headed to the mountains, leave the gasoline-powered car at home and save a few pennies on fuel. 90005 90004 Thanks to Vishal Thakur, 23, from Hamirpur, India, for this question. 90005 90004 90005 .