Detergency additives

The level of injector fouling is most often illustrated in terms of residual flow (RF) expressed as a percentage of the flow under new conditions for a given needle lift. An RF on the order of 20% for a lift of 0.1 mm is a good compromise. This level may not be achieved with certain aromatic or naphthenic diesel fuels. The best recourse is then detergent additive addition. 

In order to meet French manufacturers fuel quality specifications, a diesel fuel should contain a detergent additive whose effectiveness will have been demonstrated by the procedure described previously. 

Concerning detergent additives, the anti-ORI additives are particularly noteworthy. 

There are between 1000 and 2000 different detergent additive formulations for gasoline. 

A second family is based on isobutene polymers (PIB) having molecular weights from 600 to 2000 that are equally important raw materials for detergent additives. So as to render them reactive with the hydrophilic part, they can be chlorinated or condensed with the maleic anhydride. A third way is based on the utilization of polypropylphenols of molecular weights between 600 and 3000. 

The role of detergent additives is to maintain clean injectors so as to insure good distribution of diesel fuel in the cylinder. The structure of these compounds is similar to that of detergents for gasoline engine admission systems. Commercialized compounds are from the succinimide family (see Figure 9.1). 

T3rpical Structures Used for Detergent Additives And Dispersants... 

Detergent additives Detergent aklylation Detergent builders... 

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). 

Fuels and Lubricants. Rare-earth neodecanoates have been claimed as additives for diesel fuels that reduce the precipitation of particles and gum (108). Neodecanoic acid has also been used in the preparation of ashless detergent additives for fuels and lubricants that reduce engine deposits in internal combustion engines (109). 

It is sometimes possible to add properties in Hquid formulations that provide additional functions. Examples in development or in commercial use as of 1993 include microencapsulation (qv) of enzymes for protection against bleach when dispersed in a Hquid detergent addition of certain polymers to protect the enzyme after it has been added to Hquid detergents (32), or to boost activity in the final appHcation addition of surfactants or wetting agents. 

Laundering Conditions Around the World. Any laundeting process is an iaterplay between the equipment used the materials entering the process, ie, detergent, additional bleach, fabric softener, or water and the procedure followed. Equipment and procedures ia three principal geographical areas are summarised ia Table 3. 

As a detergent additive, it can also reactivate detergents or soaps that have combined with calcium to make an insoluble scum. The TSPP sequesters the calcium, replacing it with sodium, which reactivates the detergent or soap, and yet keeps the calcium from precipitating out of solution. 

Because phosphates cause eutrophication of water (algae grow because of the fertilizing power of phosphates), it is seldom used as a detergent additive except in toothpastes. 

Amine sulfide terminal moieties can be imparted into vinyl polymers by using aminethiols as chain transfer agents in aqueous radical polymerization [1182]. The polymers are useful as mineral dispersants. Other uses are as water-treatment additives for boiler waters, cooling towers, reverse osmosis applications, and geothermal processes and oil wells and as detergent additives... 

Demulsifier Usually added to help prevent the fuel detergent additive from emulsifying with water emulsified detergents will not perform... 

TABLE 4-11. Elements Found in Most Engine Oil Detergent Additive Packages... 

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