Blow-by gases

BlOW-by Combustion gases which are forced past the piston rings and into the crankcase of an internal combustion engine. Blow-by gases may contain NO, SCX, CO, COz,water vapor, hydrocarbon gases, and soot. In combination with water, some of these gases can form corrosive acids. 

A portion of these by-products enters the crankcase via blow-by gases and adsorption in the thin lubricant film. It seems that these mechanisms are partly... 

As for all additives, interactions with other additives in solution, Fig. 3.16, and competition for surface reaction sites together with the effect of environmental factors such as temperature, blow-by gases, water and fuel dilution have variable effects on the formation of the film. Because ZDDPs are much more widely used as antiwear performance additives compared to other classes of compounds, these additive effects will now be discussed in greater detail than has been the case for other classes of anti-wear/friction additives. In particular the influence of structure, concentration, dispersant, detergent, antioxidancy and friction modifier on friction and wear will be discussed. In addition the influence of NO c and H2O will be briefly illustrated. 

High temperatures and the reactive blow-by gases lead to rapid oxidation of the thin oil film, which is initiated by hydroxyl and NO2 radicals [89], Undoubtedly, the rate of oxidation in the initial phase is dominated by NO2 according to the following reaction sequence (4.71) [89, 90] ... 

To meet the US 2007 emissions standards, some OEMs re-circulate a portion of the engine blow-by gases back into the engine, in most cases by directing them upstream of the turbocharger. As of 2009, no test is currently available to measure turbocharger deposits in API CJ-4. 

In future the use of EGR is expected to increase for certain applications, particularly those which do not use Selective Catalytic Reduction NOx after-treatment. When this happens, the levels of acids entering the lubricant via the blow-by gases may increase. Because of this, there is an expectation that drain intervals may need to be lowered if the base number of the lubricant drops too quickly. To counter this, reductions in fuel sulphur will help offset the increased levels of EGR and may allow lubricant drain intervals to be maintained. A good example is in North America where higher cooled EGR rates for US 2007 engines are used in combination with less than 15 ppm sulphur diesel. Maximum lubricant drain intervals have been maintained at around 25,000 miles (40,000 km). 

Internal sources of contamination include wear products from the rubbing surfaces of the engine, blow-by gases leaking past the piston rings and degradation of the oil... 

Polyolefins can be coated with other materials, such as poly(vinylidene chloride), in order to reduce the permeability by gases of the walls of blow mouldings or film (thus extending the shelf-lives of products contained in them) however, barrier coatings of this nature cannot be applied satisfactorily to the untreated surfaces. 

Solid material that is heated in industrial furnaces is not necessarily continuous. Very often, the charge consists of coiled strip material or separate pieces piled to various depths or close side by side. In such cases, heat only can fiow from one piece to the adjacent piece through small contact points on their surfaces, or through gas-filled spaces—the thermal conductivity of which is very small. A pile of crankshafts is an example of low overall conductance, but high-velocity burners may be able to blow some gases between the pieces. 

A drain system that is connected directly to pressure vessels is called a "pressure" or "closed" drain system. A drain system that collects liquids that spill on the ground is an "atmospheric," "gravity," or "open" drain. The liquid in a closed drain system must be assumed to contain dissolved gases that flash in the drain system and can become a hazard if not handled properly. In addition, it must be assumed that a closed drain valve could be left open by accident. Once the liquid has drained out of the vessel, a large amount of gas will flow out of the vessel into the closed drain system (gas blow-by) and will have to be handled safely. Thus, closed drain systems should always be routed to a pressure vessel and should never be connected to an open drain system. 

O-ring channel and not provide a space between itself and the upstream channel wall. Thus it is probable the O-ring would not be pressure actuated to seal the gap in time to preclude joint failure due to blow-by and erosion from hot combustion gases. 

The sea water is first treated with chlorine in acid solution (sulphuric acid is added) and very dilute bromine is obtained by blowing air through the solution. This is mixed with sulphur dioxide and the gases passed up a tower down which water trickles ... 

Whereas there is no universally accepted specification for marketed natural gas, standards addressed in the United States are Hsted in Table 6 (8). In addition to these specifications, the combustion behavior of natural gases is frequently characteri2ed by several parameters that aid in assessing the influence of compositional variations on the performance of a gas burner or burner configuration. The parameters of flash-back and blow-off limits help to define the operational limits of a burner with respect to flow rates. The yeUow-tip index helps to define the conditions under which components of the natural gas do not undergo complete combustion, and the characteristic blue flame of natural gas burners begins to show yellow at the flame tip. These... 

---