Additive tank for a vehicle having an internal combustion engine

1. An additive tank for a vehicle having an internal combustion engine, comprising:

a flexible bag that defines an outlet orifice in fluid communication with a pipe connected to a fuel tank of the vehicle;

a liquid fuel additive; and

a pressure device that applies pressure to an outside of the flexible bag so as to reduce the internal volume of said flexible bag and expel the liquid fuel additive out of the flexible bag, through the outlet orifice and into said fuel tank of the vehicle.

2. The additive tank according to claim 1 , further comprising a rigid cartridge and wherein the flexible bag is contained inside the rigid cartridge.

3. The additive tank according claim 2 , wherein the rigid cartridge includes a fuel filter.

4. The additive tank according to claim 2 , wherein said pressure device includes a pump that pumps fluid into said rigid cartridge and outside said flexible bag so as to apply pressure to an outside of the flexible bag.

5. The additive tank according to claim 4 , wherein said pump pumps fuel from said fuel tank into said rigid cartridge.

6. The additive tank according to claim 5 , wherein said rigid cartridge filters said fuel pumped by said pump into said rigid cartridge.

7. The additive tank according to claim 1 , wherein the pressure device includes a spring.

8. The additive tank according to claim 1 , wherein the pressure device includes a pump built into the vehicle and which therein fulfils some other function.

9. The additive tank according to claim 8 , wherein the pump is a main engine fuel feed pump.

10. The additive tank according to claim 1 , wherein the flexible bag includes an electrically-operated valve connected to a computer so as to meter the liquid fuel additive correctly.

11. A fuel system comprising a fuel tank and equipped with an additive tank according to claim 1 , wherein said additive tank is connected to said fuel tank via a pipe.

12. The fuel system according to the claim 11 , wherein:

the fuel is diesel and the engine is a self-ignition engine; and

the liquid fuel additive comprises a composition, in solution in a hydrocarbon-containing solvent, of a catalyst for low-temperature combustion of carbonated solid particles produced by incomplete combustion of the diesel in the engine.

13. The additive tank according to claim 1 , wherein said liquid fuel additive, when mixed with fuel of said vehicle, lowers a combustion temperature of solid particles in exhaust gases for said vehicle.