Causes And Effects Of Engine Oil Fuel Dilution

by Sky Smith Blogger

Fuel dilution of engine oil is an issue that many contemporary combustion engines suffer from. It is a process in which gasoline is gradually lost into engine oil as it goes towards the crankcase and is also known as "crankcase dilution." It is a process that occurs around 8 times every 1000 rpm for each cylinder, and while it occurs in every engine, it is a factor that causes a substantial amount of wear to the engine. It is also one of the key reasons why many engines undergo frequent oil testing, as it is unavoidable that every engine will encounter it. In this post, we will look at the primary sources of fuel dilution and the problems that it might create.

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Dilution of oil

Another result of gasoline spilling into the crankcase is oil dilution. This causes the lubricant to lose viscosity, which means that the films generated are weaker and less capable of withstanding strong stresses that can occur at specific spots, such as the rod bearings and crankshaft sections.

What happens if the viscosity falls too low? This produces contact between the metal surfaces, resulting in quick wear of the bearings due to friction.

A third consequence of gasoline going through the crankcase is then connected to biofuel. Currently, both diesel fuel and gasoline contain biofuels in their formulations (biodiesel in the first case, and bioethanol in the second).

As the fuel is been heated in the crankcase, part of it evaporates, resulting in a concentration of biofuel in the case of diesel fuel. This causes the biodiesel to be less fluid and viscous than diesel fuel, causing the lubricant to thicken.

For example, if we use a diesel fuel containing 7% biodiesel, the diesel fuel component evaporates in the crankcase, resulting in a biofuel concentration of more than 10% biodiesel. The viscosity of the lubricant and fuel combination rises as a result of this impact, and bearing wear can accelerate dramatically.

Wet stacking

Wet stacking happens in cold engines, i.e. engines that have not yet attained their optimal working temperature. Colder engines have poorer combustion efficiency than hot engines, causing the fuel to ignite later in the compression stroke (because of the lower internal temperatures). This can also cause the gasoline flowing out of the injector to cling to the cylinder walls. Once the gasoline directly adheres to the sidewalls, it will slowly enter the oil system by being got scraped off by the piston rings and entering the crankcase.

Inadequate maintenance

Fuel dilution occurs slowly inside an oil system. As a result, when some oil becomes contaminated with a trace quantity of gasoline, the consequences are negligible and have no bearing on the oil's performance (or the engine in general). If it isn't allowed to build up, that's when problems develop since excessive levels of gasoline dilution will harm the performance of the oil and the engine. As a result, frequent maintenance in the form of oil checks and changes can prevent fuel dilution from causing any problems, but ignoring these fundamental inspections might have disastrous results.

Checking the fuel injector nozzles, in addition to regular oil checks and changes, can help to reduce the occurrence of fuel dilution—as dirty nozzles can prevent the fuel from atomizing correctly, and thus prevent the fuel from combusting efficiently—so not keeping up with maintenance in this area is another way of increasing the potential for fuel dilution to occur.

Engine Upgrades

Engine modifications, particularly those that modify the way gasoline is then fed into an engine, are another approach to increase the risk of fuel dilution inside the engine oil. This is frequently indicated through alterations that create significantly more smoke. Because smoke goes through the crankcase before exiting via the tailpipe, additional smoke naturally enters the oil system, causing the oil to be clearly diluted by the gasoline and introducing various forms of oil pollution.

The Effects of Fuel Dilution on Engine Oil

There are several issues with fuel dilution that affect the performance of the oil and the engine in general. Excessive dilution can cause significant wear and, eventually, engine failure.

The most significant difficulty caused by fuel dilution is a decrease in oil viscosity, as fuel has a significantly lower viscosity than oil (as well as lower vapor pressure and thinning effect), which can lead the oil-fuel combination to adopt a viscosity lower than it was been intended for-This causes the oil to have less effective lubricating properties and reduces the strength of the oil film, which increases the amount of wear on the cylinder liner and bearings—this is since the oil film is critical for reducing friction between moving components by providing a barrier, and thinning the oil reduces the effectiveness of the barrier, increasing the amount of wear on the system.

Several other concerns might arise as a result of lower oil viscosity (or damaged oil in general), including decreased additive efficacy, increased volatility, and increased oxidation rate inside the oil

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