Combustion chamber deposits , gasoline engine

Deposits can form within the combustion chamber of a gasoline engine. These deposits are complex in nature and can contain components from fuel combustion, from the lubricating oil, and from some additives. Typically, the heavier fuel and lubricant components such as condensed aromatics and bright stocks contribute most significantly to combustion chamber deposits. 

Crankcase Dilution of Motor Oil/Carbon Deposits in Combustion Chamber of Gasoline and Diesel Engines... 

In gasoline engines, most detergents will prevent deposit formation on carburetors, fuel injectors, and intake valves. Some detergents also possess the ability to remove existing deposits from intake valves and control the formation of deposits within the combustion chamber of an engine. See FIGURE 6-14. 

G.T. Kalghatgi, Combustion Chamber Deposits in Gasoline Engines - A Literature Review, SAE Technical Paper 952443 (1995). 

Detergent Additives. Diesel engine deposits ate most troublesome in the fuel dehvery system, ie, the fuel pump and both fuel side and combustion side of the injectors. Small clearances and high pressures mean that even small amounts of deposits have the potential to cause maldistribution and poor atomization in the combustion chamber. The same types of additives used in gasoline ate used in diesel fuel. Low molecular weight amines can also provide some corrosion inhibition as well as some color stabilization. Whereas detergents have been shown to be effective in certain tests, the benefit in widespread use is not fully agreed upon (77). 

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