1
What is?
oil coke and the like inside the engine resulting product. When the engine oil sludge left behind to work long hours, dust, and other debris. Sludge inside the cylinder is generally referred to as “coke.” The throttle valve in the sludge referred to as “oil”, gasoline injectors at the intake and spongy referred to as “gumming.”
2
Causes?
1 in normal engine operation, gasoline and engine oil to enter the combustion chamber normally, under conditions of insufficient oxygen supply, is not completely burned in the cylinder, produce soot and lubricants charred particles. When the engine continues to operate, subject to further oxidation becomes gelatinous. Firmly glued to the top of the piston, piston ring, valve back surface, the inner surface of the intake pipe, the throttle body and the combustion chamber and the like. Repeated action under high temperature, colloid turn into asphaltenes, resins and carbonaceous matter, thereby forming coke.
2, crankcase ventilation settings. To prevent contamination of the air, the automotive design engineers in the engine exhaust gas is introduced directly into the intake manifold, together with fresh air for combustion into the combustion chamber. Filled with high temperature oil vapor with the fresh intake air with the intake manifold, and a valve part attached to the back wall, with the other part of the mixed gas stream to form a mixed feed vapor intake valve at the injected fuel, after being discharged into the combustion chamber outside the car.
3, gasoline, during storage and transport, easy and the air oxidation reaction to produce a gelatinous substance, or the content of the gasoline itself gum is high (poor quality gasoline), gasoline with gum which by the vehicle fuel supply system into the internal combustion chamber, combustion of gasoline, and then withAfter, it will make the fuel supply system fuel injector, combustion chamber, piston ring grooves, a spark plug, an intake valve back, and other parts of the engine intake coke and produce a lot of oil and the like.
4, congested city traffic, the vehicle is always in a state of stop and go, the engine can not be high-speed operation, fleeing or fuel oil can not be one hundred percent of the combustion chamber combustion, unburnt part of the fuel formed under the action of heat and oxygen in the gum, the part adhered to the inner surface of the engine, then after high temperature to form coke.
5, by the decision EFI engine control features, when the cylinder every time work is the first re-ignition fuel injection, when we turned off the engine ignition moment is immediately cut off, but the duty cycle of the spray the gasoline can not be recovered, only the intake valve and combustion chamber attached to the wall, it is likely to be volatile gasoline, but gasoline has stayed gum and wax, wax and long run gasoline gum piled thick, hardened after repeated heating coke is formed.
In short, the engine and oil and other produce coke is inevitable, but when too much coke in the engine will result in poor engine work, produce different fault phenomenon.
3
What’s the harm?
a great influence on the combustion chamber of the engine coke normal operation, such as closing a valve leading to lax, intake or exhaust valve leakage, knocking. Knock particular, since severe carbon deposition decreases the actual volume of the cylinder, the compression ratio is increased, while carbon deposition due to the poor heat dissipation would have been burned in a high temperature environment of red, so in addition to the high temperature compressed air mixture ignition timing with a spark plug is but also by the high temperature of the cylinder coke random lit, knock.
4
How to prevent?
regular maintenance, clean oil and gas path; recommended every 4000-8000km (according to the use and the actual situation of the vehicle) cleaning air grid (as the case replacement), washed a throttle valve, clean up fire mouth; every 15000-25000km (based on usage and the actual situation of the vehicle) cleaning the combustion chamber and intake throttle oil-related, check the diesel filter as the case may be replaced; strengthen their standard of driving, avoid prolonged idling stop, to avoid stalling immediately after high-speed driving, avoid high speed immediately after the start, to avoid low-speed shift.