We claim:
1. A fuel composition which comprises at least:
- a fuel derived from one or more sources selected from the group consisting of mineral, animal, vegetable and synthetic sources,
- a compound (T1) selected from: polyalkylene glycols, C1-C12 alkyl ethers of polyalkylene glycol, and mixtures thereof,
- a compound (T2) selected from nonionic emulsifiers.

2. The composition as claimed in claim 1, wherein the fuel comprises at least 50% by weight of a diesel fuel, preferably at least 70% by weight, more preferentially at least 90% by weight, relative to the total weight of fuel, more preferentially still the fuel consists of diesel fuel.
3. The composition as claimed in either one of the preceding claims, wherein the fuel comprises at least 50 ppm of water, preferably at least 100 ppm, more preferentially still at least 150 ppm.
4. The composition as claimed in any one of the preceding claims, wherein the compound (T1) is selected from polyethylene glycols, C1-C12 alkyl ethers of polyethylene glycol, and mixtures thereof.
5. The composition as claimed in claim 4, wherein the compound (T1) is selected from C1-C6 alkyl ethers of polyethylene glycol comprising two to six ethylene glycol units, preferably diethylene glycol methyl ether.
6. The composition as claimed in any one of the preceding claims, wherein the compound (T2) is selected from polyol esters of saturated or unsaturated, linear or branched, cyclic or acyclic C1 to C36, preferably C4 to C30 monocarboxylic aliphatic hydrocarbons, it being possible for said esters to be taken alone or as a mixture.
7. The composition as claimed in claim 6, wherein the compound (T2) is obtained by esterification between:

- one or more C1 to C36, preferably C4 to C30 alkylcarboxylic or alkenylcarboxylic acids, optionally comprising one or more ethylenic bonds; and
- a linear or branched, cyclic or acyclic C4-C20 polyol optionally comprising one or more heterocycles with 5 to 6 atoms, preferably one or two heterocycles with 4 to 5 carbon atoms and an oxygen atom.

8. The composition as claimed in claim 7, wherein the alkylcarboxylic and alkenylcarboxylic acids are selected from the group consisting of stearic, isostearic, linolenic, oleic, linoleic, behenic, arachidonic, ricinoleic, palmitic, myristic, lauric, capric acids, taken alone or as a mixture.
9. The composition as claimed in any one of claims 6 to 8, wherein the polyol is selected from oxygenated C4-C20 hydrocarbon-based molecules comprising at least two, preferably at least three hydroxyl functions.
10. The composition as claimed in any one of claims 6 to 9, wherein the polyol is selected from the group consisting of erythritol, xylitol, arabitol, ribitol, sorbitol, maltitol, isomaltitol, lactitol, volemitol, mannitol, pentaerythritol, 2-hydroxymethyl-1,3-propanediol, 1,1,1-tri(hydroxymethyl)ethane, trimethylolpropane, sorbitan, isosorbide, and carbohydrates such as saccharose, fructose, maltose and glucose.
11. The composition as claimed in claim 10, wherein the compound (T2) is selected from sorbitan esters and isosorbide esters, preferably from sorbitan monoesters, diesters and triesters and isosorbide monoesters and diesters, taken alone or as a mixture.
12. The composition as claimed in claim 11, wherein the compound (T2) is selected from mixtures of sorbitan partial esters, preferably mixtures of sorbitan monooleate, dioleate and trioleate.
13. The composition as claimed in any one of claims 1 to 9, wherein the compound (T2) is selected from monoester(s) and diester(s) of polyglycerols having from 2 to 10 glycerol units per molecule, preferably from 2 to 5 glycerol units per molecule, and mixtures thereof.
14. The composition as claimed in any one of the preceding claims, which further comprises at least one detergent additive.
15. The composition as claimed in claim 14, wherein the detergent additive is selected from succinimides, polyetheramines and quaternary ammonium salts.
16. The composition as claimed in claim 14 or claim 15, wherein the detergent additive is selected from polyisobutylene succinimides and polyisobutylenes functionalized by a quaternary ammonium group.
17. The composition as claimed in any one of the preceding claims, comprising:

• from 5 to 1000 ppm, preferably from 50 to 500 ppm, more preferentially still from 100 to 300 ppm of additive (T1),
• from 5 to 500 ppm, preferably from 25 to 200 ppm, more preferentially still from 50 to 100 ppm of additive (T2).
18. The composition as claimed in any one of the preceding claims, comprising:
• from 5 to 1000 ppm, preferably from 50 to 500 ppm, more preferentially still from 100 to 300 ppm of additive (T1),
• from 5 to 500 ppm, preferably from 25 to 200 ppm, more preferentially still from 50 to 100 ppm of additive (T2),
• from 1 to 1000 ppm, more preferentially from 5 to 400 ppm of at least one detergent additive.
19. The composition as claimed in any one of the preceding claims, comprising:
• from 5 to 1000 ppm, preferably from 50 to 500 ppm, more preferentially still from 100 to 300 ppm of additive (T1),
• from 5 to 500 ppm, preferably from 25 to 200 ppm, more preferentially still from 50 to 100 ppm of additive (T2),
• from 1 to 1000 ppm, more preferentially from 5 to 400 ppm of at least one detergent additive,
• at least 50 ppm of water, more preferentially still at least 100 ppm of water, better still at least 150 ppm of water.

20. The composition as claimed in any one of the preceding claims, wherein the (T1):(T2) weight ratio is from 10:1 to 1:10, preferentially from 10:1 to 1:1.
21. A composition of fuel additives that is intended for a vehicle equipped with an internal combustion engine, this composition being able to be used to formulate a fuel composition as claimed in any one of claims 1 to 20 and which comprises at least:

- a compound (T1) selected from C1-C6 alkyl ethers of polyethylene glycol comprising two to six ethylene glycol units, preferably diethylene glycol methyl ether,
- a compound (T2) selected from esters of one or more C1 to C36, preferably C4 to C36 alkylcarboxylic or alkenylcarboxylic acids and of a polyol selected from sorbitan and isosorbide, taken alone or as a mixture, and optionally,
- a detergent additive, preferably a detergent additive comprising a quaternary ammonium function.
22. The composition of additives as claimed in claim 21 which comprises at least:

- a compound (T1) which is diethylene glycol methyl ether,
- a compound (T2) selected from sorbitan partial esters, taken alone or as a mixture, and optionally,
- a detergent additive, preferably a detergent additive comprising a quaternary ammonium function.

23. A process for formulating a fuel intended for a vehicle equipped with an internal combustion engine, comprising the additization of a fuel with at least one additive (T1) selected from: polyalkylene glycols and C1-C12 alkyl ethers of polyalkylene glycol, and at least one compound (T2) selected from nonionic emulsifiers.
24. The process as claimed in claim 23, wherein the fuel is additized with at least one detergent additive.
25. The process as claimed in either one of claims 23 and 24, wherein the fuel comprises at least 50 ppm of water, more preferentially still at least 100 ppm of water, better still at least 150 ppm of water.
26. The use of a composition of additives in a fuel intended for a vehicle equipped with an internal combustion engine, to prevent, avoid or delay the formation of ice crystals or flakes in said fuel, wherein the composition of additives comprises:

- at least one additive (T1) selected from: polyalkylene glycols and C1-C12 alkyl ethers of polyalkylene glycol, and
- at least one compound (T2) selected from nonionic emulsifiers.
27. The use as claimed in claim 26, wherein the fuel comprises at least 50 ppm of
water, more preferentially still at least 100 ppm of water, better still at least 150 ppm
of water.