1、API PUBLx1571 76 0732290 0550750 Tbb = Diesel Fuel I Questions therefore, wax crystals or gelling occurs at a lower tem- perature than for No. 2-D. Additives also can improve the low-temperature perfor- mance of No. 2-D. Additional informa- tion on winter diesel fuel is found in API Publication 1577
2、, “Winter Diesel- Questions and Answers.” CAUTION: Gasoline should not be used to dilute diesel fuel because the mixture has much greater flammability and explosive potential than either gasoline or diesel fuel alone. 15. Q. What factors affect low temper- ature performance? A. Many factors, such as
3、 battery condition, cetane number, and injector settings, can affect low temperature starting and perfor- mance. However, the most important fuel characteristic is the cloud point temperature. 16. Q. Why are the cloud point and pour point temperatures impor- tant? A. Cloud point is the temperature a
4、t which wax crystals first appear in the fuel. As the temperature drops below the cloud point, the wax crystals continue to grow and can result in filter plugging and engine stalling or non-starting. Generally, No. 1- D and winterized No. 2-D grades have lower cloud points than Grade No. 2-D fuel. T
5、he pour point, generally lower than the cloud point, is 3% (5OF) higher than the temperature at ,which the fuel will no JQnger flow under prescribed laboratory test condi- tions. Petroleum manufacturers, on the basis of area temperature studies, manufacture and distribute fuels with cloud points and
6、 pour points that have been adjusted so that the fuel should operate satisfactorily in the various localities concerned. 17. Q. How can I improve low tempera- ture operability by equipment modification? - - A. Low temperature operability can be improved by properly installing tank heaters, fuel-line
7、 heaters, and heated fuel filters. Many equipment manufacturers offer these as options and, in some cases, as standard equipment. Low temperature operability of vehicles not equipped with fuel heating devices must rely on a fuels cold-flow characteris- tics for satisfactory operation. If vehicles ar
8、e equipped with fuel-heating devices, good operability may be obtained at fuel tank temperatures below the cloud point. 18. Q. Are diesel cold-starting fluids effective? A. When properly used, diesel cold-starting fluids can be a valuable aid to cold start- ing. These fluids are usually composed of
9、a mixture of ethyl ether and a blend of solvent materials pressurized with carbon dioxide (CO,). For effective response, the secondary component combined with the ether should have high volatility and high-cetane qualities. Care should be exercised, however, to avoid overdosing an engine with starti
10、ng fluids, as severe mechanical damage can result. CAUTION: The engine manufacturers recommendations must be referred to before using any starting aids. Performance Issues 19. Q. Why do diesel engines smoke? A. Diesel engine smoke is caused by incom- plete combustion. White smoke is caused by tiny d
11、roplets of unburned fuel resulting from engine misfiring at low temperature. This smoke should disappear as the engine warms up. Black smoke could be caused by a faulty injector, insufficient air, and overloading and/or overfueling the engine. Blue-gray smoke is the result of burning lubricating oil
12、 and is an indication the engine is in poor mechanical condition. 20. Q. How does water get into diesel fuel and what problems can it cause? A. Water gets into diesel fuel storage and vehi- cle tanks in several ways-by condensation, during transportation, by leakage through faulty fill pipes or vent
13、s, and by careless han- dling. Water can cause injector nozzle and pump corrosion, bacteria and fungi growth, and fuel filter plugging with materials resulting from corrosion or microbial growth. Both vehicle and storage tanks should be checked frequently for water and drained or pumped as necessary
14、. In extreme Q. A. 2. A. API PUBL8157L 96 0732290 0550762 788 cases, biocides may be required to control bacterial growth. In cold northern winters, ice formation in fuels containing water creates severe fuel line and filter plugging problems. Regularly removing the water is the most effective means
15、 of preventing this prob- lem; however, small quantities of alcohol may be used on an emergency basis to prevent fuel line and filter freeze-ups. (See Question 24, Item 5.) 21. What are some fuel-handling causes of poor diesel engine performance? Contamination of fuel by water and dirt entering the
16、fuel as a result of careless fuel handling may cause poor diesel engine per- formance. Extreme care must be exercised. Fuel-tank caps, dispensing nozzles, and hoses should be kept clean to eliminate potential sources of contamination. Regularly removing water from storage tanks, vehicle fuel tanks,
17、and filter bowls is important. Dry storage systems will reduce fuel emulsion problems, injection system corrosion, and microbial growth. 22. Does diesel fuel color affect performance? No. There is no relationship between natur- al diesel fuel color and such desirable diesel fuel qualities as heat co
18、ntent, viscosity, cloud point, cetane number, or distillation range. Diesel fuel color varies with the crude source, refinery methods, and the use of dyes. However, if the fuel color darkens API PUBLxL57L 96 0732290 0550763 bL4 H appreciably during storage, this could indicate oxidation and/or conta
19、mination from dirt, water, or other sources, which can cause operating problems. 23. Q. What effect does blending used lubricating oil into diesel fuel have on engine performance and fuel quality? A. You should consult your engine manufac- turer regarding the blending of used lubricating oils into d
20、iesel fuel. This practice may adversely affect fuel quality features and could lead to fuel system and piston deposits, increased exhaust emis- sions, and fuel-filter plugging. This prac- tice may also result in the diesel fuel being out of compliance with state or fed- eral regulations or other spe
21、cifications. Additives 24. used in diesel fuels and for what purposes? Q. What additives are normally A. If required, fuel suppliers generally blend the necessary additives into the fuel before distribution. It should be noted that most engine manufacturers recommend against the use of additives oth
22、er than those added by fuel suppliers. The following types of additives may be used to enhance particu- lar fuel properties. Not all fuel will con- tain any or all of these additives. 1. Oxidation inhibitors are used to reduce the formation of gums and insolu- ble residues that can clog fuel filters
23、. ApI pUBLx1571 96 = 07312270 05507b4 550 2. Ignition quality (cetane number) improvers are used to increase the cetane number when the base fuel cetane does not meet requirements. 3. Detergent-dispersant additives help keep fuel-insoluble materials in suspension and are helpful in maintaining a cle
24、an engine and fuel delivery system. 4. Rust preventives and metal deactiva- tors are used when storage, handling, or shipping conditions warrant. 5. Anti-icing additives, such as alcohols, may be used in very cold areas in winter to help pre- vent ice fiom plugging fuel lines and filters. CAUTION Do
25、 not use excessive amounts of alcohol since alcohol lowers the cetane number and flash point and can increase cor- rosive wear on the fuel pump and injectors. In all cases, follow the manufacturers recom- mended maximum dosage. Never use more than one pint (473 milliliters) of alcohol per 100 gallon
26、s (379 liters) of fuel. Many engine manufacturers specifically warn against using alcohols because of the adverse effects on pumps, pump seals, and flash point. 6. Cold-flow improvers, when used selectively, may permit operation at temperatures below the cloud point temperature of the fuel in cer- t
27、ain diesel equipment. Effectiveness varies with crude oil source and refining techniques. 7. Biocides may be added to diesel fuel to prevent microbial growth. Microbial growth in stored fuel creates insoluble par- ticles that can cause fuel-filter clogging. 8. Red dye is required to be added to high
28、-sulfur and low-sulfur tax-exempt diesel fuel by federal regulations. 7. Lubricity additives may be used in cer- tain applications to improve the lubricat- ing ability of the fuel. Q. A. Fuel suppliers carefully weigh the benefits and possible adverse effects of all of these various additives in the
29、 fuel they market. 25. Can diesel fuel additives, such as those offered by automotive chemical manufacturers, improve diesel fuel and/or engine performance? Many of the over-the-counter automotive chemicals may provide some improve- ments, such as low-temperature flow and cetane performance. However
30、, engine manufacturers usually recommend against using additives other than those added by fuel suppliers. Additional Information 26. Q. Where can I get more informa- tion about diesel fuel? A. Most petroleum companies are happy to answer inquiries about their products. You can also write or telepho
31、ne the fol- lowing organizations: American Petroleum Institute 1220 L Street, NW Washington, DC 20005 202-682-8000 Society of Automotive Engineers 400 Commonwealth Drive Warrendale, Pennsylvania 15096 412-776-4841 American Society for Testing and Materials 100 Barr Harbor Drive West Conshohocken, PA 19428 610-832-9500 PG-01400-1/96-1OM (1E) American 1220 L Street, Northwest Petroleum Washington, D.C. 20005 Institute 202-682-8000 Order No. F157104
