Evaporative fuel vapor emission control systems

Patent metadata

Field	Value
Publication number	US-9732649-B2
Application number	US-201314434690-A
Country	US
Kind code	B2
Filing date	Oct 10, 2013
Priority date	Oct 10, 2012
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

An evaporative emission control canister system comprises an initial adsorbent volume having an effective incremental adsorption capacity at 25° C. of greater than 35 grams n-butane/L between vapor concentration of 5 vol % and 50 vol % n-butane, and at least one subsequent adsorbent volume having an effective incremental adsorption capacity at 25° C. of less than 35 grams n-butane/L between vapor concentration of 5 vol % and 50 vol % n-butane, an effective butane working capacity (BWC) of less than 3 g/dL, and a g-total BWC of between 2 grams and 6 grams. The evaporative emission control canister system has a two-day diurnal breathing loss (DBL) emissions of no more than 20 mg at no more than 210 liters of purge applied after the 40 g/hr butane loading step.

First claim

The invention claimed is:

1. An evaporative emission control canister system, including one or more canisters and comprising:
an initial adsorbent volume having an effective incremental adsorption capacity at 25° C. of greater than 35 grams n-butane/L between vapor concentration of 5 vol % and 50 vol % n-butane; and
at least one subsequent adsorbent volume having an effective incremental adsorption capacity at 25° C. of less than 35 grams n-butane/L between vapor concentration of 5 vol % and 50 vol % n-butane, an effective butane working capacity (BWC) of less than 3 g/dL, and a g-total BWC of between 2 grams and 6 grams,
wherein the initial adsorbent volume and the at least one subsequent adsorbent volume are located within a single canister, or the initial adsorbent volume and the at least one subsequent adsorbent volume are located in separate canisters that are connected to permit sequential contact by fuel vapor, and
wherein the canister system has a two-day diurnal breathing loss (DBL) emissions of no more than 20 mg at no more than about 210 liters of purge applied after the 40 g/hr butane loading step.

2. The canister system of claim 1 , comprising a single subsequent adsorbent volume.

3. The canister system of claim 1 , comprising multiple subsequent adsorbent volumes.

4. The canister system of claim 1 , wherein the initial adsorbent volume, the at least one subsequent adsorbent volume, or both includes an adsorbent selected from the group consisting of activated carbon, carbon charcoal, zeolites, clays, porous polymers, porous alumina, porous silica, molecular sieves, kaolin, titania, ceria, and combinations thereof.

5. The canister system of claim 4 , wherein the activated carbon is derived from a material including a member selected from the group consisting of wood, wood dust, wood flour, cotton linters, peat, coal, coconut, lignite, carbohydrates, petroleum pitch, petroleum coke, coal tar pitch, fruit pits, fruit stones, nut shells, nut pits, sawdust, palm, vegetables, synthetic polymer, natural polymer, lignocellulosic material, and combinations thereof.

6. The canister system of claim 1 , wherein a form of adsorbent in the initial adsorbent volume, the at least one subsequent adsorbent volume, or both includes a member selected from the group consisting of granular, pellet, spherical, honeycomb, monolith, pelletized cylindrical, particulate media of uniform shape, particulate media of non-uniform shape, structured media of extruded form, structured media of wound form, structured media of folded form, structured media of pleated form, structured media of corrugated form, structured media of poured form, structured media of bonded form, non-wovens, wovens, sheet, paper, foam, hollow-cylinder, star, twisted spiral, asterisk, configured ribbons, and combinations thereof.

7. The canister system of claim 1 , wherein the at least one subsequent adsorbent volume includes a volumetric diluent.

8. The canister system of claim 7 , wherein the volumetric diluent includes a member selected from the group consisting of inert spacer particles, trapped air spaces, foams, fibers, screens, and combinations thereof.

9. The canister system of claim 7 , wherein the volumetric diluent includes an adsorbent material formed into a high voidage shape selected from the group consisting of stars, hollow tubes, asterisks, spirals, cylinders, configured ribbons, honeycombs, monoliths, and combinations thereof.

10. The canister system of claim 1 , wherein the at least one subsequent adsorbent volume has a total volume butane working capacity of more than 2 grams.

11. The canister system of claim 1 , wherein the canister system has a two-day diurnal breathing loss (DBL) emissions of no more than 20 mg at no more than 157.5 liters of purge applied after the 40 g/hr butane loading step.

12. The canister system of claim 1 , wherein the canister system has a two-day diurnal breathing loss (DBL) emissions of no more than 20 mg at no more than about 100 bed volume of purge applied after the 40 g/hr butane loading step.

13. The canister system of claim 1 , wherein the canister system has a two-day diurnal breathing loss (DBL) emissions of no more than 20 mg at no more than about 75 bed volume of purge applied after the 40 g/hr butane loading step.

14. An evaporative emission control system, comprising:
a fuel tank for storing fuel;
an engine having an air induction system and adapted to consume the fuel;
an evaporative emission control canister system having a two-day diurnal breathing loss (DBL) emissions of no more than 20 mg at no more than about 210 liters of purge applied after the 40 g/hr butane loading step, the canister system comprising:
an initial adsorbent volume having an effective incremental adsorption capacity at 25° C. of greater than 35 grams n-butane/L between vapor concentration of 5 vol % and 50 vol % n-butane, and
at least one subsequent adsorbent volume having an effective incremental adsorption capacity at 25° C. of less than 35 grams n-butane/L between vapor concentration of 5 vol % and 50 vol % n-butane, an effective butane working capacity (BWC) of less than 3 g/dL, and a g-total BWC of between 2 grams and 6 grams;

a fuel vapor inlet conduit connecting the evaporative emission control canister system to the fuel tank;
a fuel vapor purge conduit connecting the evaporative emission control canister system to the air induction system of the engine; and
a vent conduit for venting the evaporative emission control canister system and for admission of purge air to the evaporative emission control canister system,
wherein the evaporative emission control canister system is defined by a fuel vapor flow path from the fuel vapor inlet conduit to the initial adsorbent volume toward the at least one subsequent adsorbent volume and the vent conduit, and by an air flow path from the vent conduit to the at least one subsequent adsorbent volume toward the initial adsorbent volume and the fuel vapor purge outlet.

15. The evaporative emission control system of claim 14 , wherein the canister system comprises one or more canister.

16. The evaporative emission control system of claim 14 , wherein the initial adsorbent volume and the at least one subsequent adsorbent volume of the canister system are located within a single canister.

17. The evaporative emission control system of claim 14 , wherein the initial adsorbent volume and the at least one subsequent adsorbent volume of the canister system are located in separate canisters that are connected to permit sequential contact by fuel vapor.

18. The evaporative emission control system of claim 14 , further comprising a heat unit.

19. The evaporative emission control system of claim 14 , wherein the canister system has a two-day diurnal breathing loss (DBL) emissions of no more than 20 mg at no more than 157.5 liters of purge applied after the 40 g/hr butane loading step.

20. The evaporative emission control system of claim 14 , wherein the canister system has a two-day diurnal breathing loss (DBL) emissions of no more than 20 mg at no more than 100 BV of purge applied after the 40 g/hr butane loading step.

21. The evaporative emission control system of claim 14 , wherein the canister system has a two-day diurnal breathing loss (DBL) emissions of no more than 20 mg at at no more than 75 BV of purge applied after the 40 g/hr butane loading step.

22. A method for reducing fuel vapor emissions in an evaporative emission control system, the metho

Assignees

• Ingevity South Carolina Llc

Inventors

• Hiltzik Laurence H
• Mccrae Peter D
• Miller James R
• Williams Roger S

Classifications

• F01N3/0807

  by using absorbents or adsorbents · CPC title

• B01D2253/102

  Carbon · CPC title

• B01D2257/7022

  Aliphatic hydrocarbons · CPC title

• B01D53/0407

  Constructional details of adsorbing systems · CPC title

• B01D2259/4145

  arranged in series · CPC title