Multum Użytecznych eInformacji

Issue with exhaust system? We have solution


oil for Mercedes

Crankcase scavenged

Crankcase scavenged
Diagram of a crankcase scavenged 2-stroke engine in operation

Some SI engines are crankcase scavenged and do not use poppet valves. Instead the crankcase and the part of the cylinder below the piston is used as a pump. The intake port is connected to the crankcase through a reed valve or a rotary disk valve driven by the engine. For each cylinder a transfer port connects in one end to the crankcase and in the other end to the cylinder wall. The exhaust port is connected directly to the cylinder wall. The transfer and exhaust port are opened and closed by the piston. The reed valve opens when the crankcase pressure is slightly below intake pressure, to let it be filled with a new charge; this happens when the piston is moving upwards. When the piston is moving downwards the pressure in the crankcase increases and the reed valve closes promptly, then the charge in the crankcase is compressed. When the piston is moving upwards, it uncovers the exhaust port and the transfer port and the higher pressure of the charge in the crankcase makes it enter the cylinder through the transfer port, blowing the exhaust gases. Lubrication is accomplished by adding 2-stroke oil to the fuel in small ratios. Petroil refers to the mix of gasoline with the aforesaid oil. This kind of 2-stroke engines has a lower efficiency than comparable 4-strokes engines and release a more polluting exhaust gases for the following conditions:

They use a total-loss lubrication system: all the lubricating oil is eventually burned along with the fuel.
There are conflicting requirements for scavenging: On one side, enough fresh charge needs to be introduced in each cycle to displace almost all the combustion gases but introducing too much of it means that a part of it gets in the exhaust.
They must use the transfer port(s) as a carefully designed and placed nozzle so that a gas current is created in a way that it sweeps the whole cylinder before reaching the exhaust port so as to expel the combustion gases, but minimize the amount of charge exhausted. 4-stroke engines have the benefit of forcibly expelling almost all of the combustion gases because during exhaust the combustion chamber is reduced to its minimum volume. In crankcase scavenged 2-stroke engines, exhaust and intake are performed mostly simultaneously and with the combustion chamber at its maximum volume.

The main advantage of 2-stroke engines of this type is mechanical simplicity and a higher power-to-weight ratio than their 4-stroke counterparts. Despite having twice as many power strokes per cycle, less than twice the power of a comparable 4-stroke engine is attainable in practice.

In the USA two stroke motorcycle and automobile engines were banned due to the pollution, although many thousands of lawn maintenance engines are in use.citation needed

Źródło: https://en.wikipedia.org/wiki/Internal_combustion_engine


In a forced (also called pressurized)

In 2-stroke crankcase scavenged engines, the interior of the crankcase, and therefore the crankshaft, connecting rod and bottom of the pistons are sprayed by the 2-stroke oil in the air-fuel-oil mixture which is then burned along with the fuel. The valve train may be contained in a compartment flooded with lubricant so that no oil pump is required.

In a splash lubrication system no oil pump is used. Instead the crankshaft dips into the oil in the sump and due to its high speed, it splashes the crankshaft, connecting rods and bottom of the pistons. The connecting rod big end caps may have an attached scoop to enhance this effect. The valve train may also be sealed in a flooded compartment, or open to the crankshaft in a way that it receives splashed oil and allows it to drain back to the sump. Splash lubrication is common for small 4-stroke engines.

In a forced (also called pressurized) lubrication system, lubrication is accomplished in a closed loop which carries motor oil to the surfaces serviced by the system and then returns the oil to a reservoir. The auxiliary equipment of an engine is typically not serviced by this loop; for instance, an alternator may use ball bearings sealed with its lubricant. The reservoir for the oil is usually the sump, and when this is the case, it is called a wet sump system. When there is a different oil reservoir the crankcase still catches it, but it is continuously drained by a dedicated pump; this is called a dry sump system.

Źródło: https://en.wikipedia.org/wiki/Internal_combustion_engine


Basic information about cars

Cars are a rather complicated layouts and worth to each control you have knowledge of the most relevant information in this regard. First of all, take a look at the information on the basic elements of the construction of the car. These include not only the engine and steering wheel, but also many related parts, for example, with the propulsion system. More than one part of the car is completely black magic to people not connected in any way with the automotive industry. Some knowledge in this area is necessary, for example when driving course, but a lot of people quickly forget obtained message. It is worth it to remember, especially because it's easier, we can use the machine as we know it.


Zobacz inne ciekawe wpisy na naszej stronie:


Artykuł o emigracji, Polakach za granicą i przewozach osób

tanie przewozy podkarpacieAutokar kontra autobusAutokar (autobus turystyczny, autobus dalekobieżny) ? autobus przystosowany do przewozów pasażerskich na duże odległości, na trasach międzymiastowych i międzynarodowych. Według definicji Europejskiej Komisji Gospodarczej, Eurostatu i Międzynarodowego Forum Transportu jest to pasażerski mechaniczny pojazd drogowy przeznaczony do przewozu więcej niż 24 osób (wliczając kierowcę) i posiadający wyłącznie miejsca siedząceŹródło: ht...

Artykuł o wirtualnym biurze

biuro wirtualne w warszawieDla kogo wirtualne biuro to doskonała propozycja? Z roku na rok istnieje coraz większe zapotrzebowanie na usługi takie, jak wirtualne biuro. Dzięki tego typu usługom możemy pozbyć się uciążliwych zadań takich, jak obsługa korespondencji i tym podobne. Wirtualne biuro to bardzo dobra opcja na start, dla przedsiębiorców dopiero wchodzących na rynek w swojej branży. Taka działalność pozwala bowiem na oszczędzenie znacznych środków, które następnie ...

Czysty dywan

pranie kanap wrocławSprzątaj regularnieNie da się ukryć tego, że bez regularnego sprzątania do naszego domu wkradnie się tak przecież niepożądany chaos, a my możemy zyskać opinię osoby, która nie panuje nad swoimi wnętrzami. Z tego powodu zwyczajnie wypada zadbać o czystość i pamiętać o tym, że przynajmniej raz w tygodniu dobrze byłoby zająć się naszymi pokojami.Możemy też zatrudnić do tego kogoś z zewnątrz, jeżeli nie dysponujemy odpowiednią do tego celu ilości...

Energia odnawialna, kolektory słoneczne - zastosowanie i porady

inwerter abb Montaż instalacji słonecznych Instalacje słoneczne zazwyczaj montują specjalne firmy, mające odpowiednie doświadczenie w tej branży. Chociaż podobno da się zbudować samodzielnie panel słoneczny, to jednak tylko wtedy, gdy korzystamy z pomocy profesjonalistów możemy być pewni, że taka instalacja działa w sposób sprawny i bezpieczny. Fotowoltaika i kolektory słoneczne to niewątpliwie energia przyszłości i trzeba przyznać, że w tej branży istnieje spore pole do...