Engine with microbial reaction purifier

• US 6,218,173 B1
• Filed: 01/26/1999
• Issued: 04/17/2001
• Est. Priority Date: 01/27/1998
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Naito, Ken
• Primary Examiner(s): Beisner, William H.
• Application Number:
  US09/237,253
• Time in Patent Office: 812 Days
• Field of Search: 435/266, 435/289.1, 435/293.1, 435/297.1, 435/297.2, 435/297.4, 435/300.1, 422/120, 422/168, 422/173, 602/82, 602/95, 602/97, 602/99, 603/10, 602/73
• US Class Current: 435/266
• CPC Class Codes: B01D 53/84 Biological processes
• CPC Class Codes: F01N 2570/10 Carbon or carbon oxides
• CPC Class Codes: F01N 3/00 Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust electric control F01N9/00; monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00 ; collecting or removing exhaust gases of vehicle engines in workshops B08B15/00, on highways E01C1/005
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A reaction purifier (100) using microorganisms which feed on harmful components in exhaust gas is installed in an exhaust passage (18, 21, 22, 23, 24) of an engine (1). The microorganisms are mixed with a culture fluid, and the culture fluid is circulated through tubes (111) in which micro holes (111A) are formed. The diameter of these holes is such as not to allow culture fluid to pass, but to allow exhaust gas to pass. The tubes (111) are housed in a casing (112), and harmful components are removed by leading exhaust gas into the casing (112) to bring into contact with the microorganisms in the culture fluid. By using the reaction purifier (100) and catalytic converter (20A, 20B) in conjunction, even better exhaust gas purifying performance is obtained.

Claims

1. A method for removing a component from an exhaust gas of an engine, comprising the steps of:

(a) burning a mixture of fuel and air in a combustion chamber of an engine to produce an exhaust gas;

(b) passing the exhaust gas through an exhaust gas passage connected to the combustion chamber; and

(c) treating the exhaust gas with a purifier installed inside the exhaust gas passage,

wherein the purifier contacts the exhaust gas with a microorganism which removes a component of the exhaust gas,

and wherein the microorganism comprises a thermophilic organism, and wherein the microorganism is mixed with a culture fluid containing water and activated sludge.

2. The method according to claim 1, wherein the microorganism feeds on carbon dioxide in the exhaust gas.

3. The method according to claim 1, wherein the microorganism is a microorganism of the type HD-1.

4. The method according to claim 1, wherein the microorganism is an Alcaligenes microorganism.

5. The method according to claim 1, wherein the microorganism feeds on hydrocarbons in the exhaust gas.

6. An engine comprising:

a combustion chamber for burning a mixture of fuel and air,

an exhaust gas passage connected to said combustion chamber, and

a reaction purifier installed in said passage, said purifier bringing a microorganism which removes a component of said exhaust gas in contact with said exhaust gas, wherein the microorganism comprises a thermophilic organism, and wherein the microorganism is mixed with a culture fluid containing water and activated sludge.

7. An engine as defined in claim 6, wherein said microorganism is a microorganism which feeds on said component without photosynthesis.

8. An engine as defined in claim 6, wherein said microorganism is mixed with a culture fluid, and said reaction purifier comprises a tube wherein a micro hole is formed which does not allow passage of said culture fluid but does allow passage of said exhaust gas, a circulating mechanism for circulating said culture fluid via said tube, and a casing connected to said passage covering said tube for leading exhaust gas into the space surrounding said tube.

9. An engine as defined in claim 8, wherein said reaction purifier comprises a temperature adjusting device for adjusting the temperature of said culture fluid.

10. An engine as defined in claim 9, wherein said reaction purifier comprises a reservoir tank comprising adiabatic walls for collecting said culture fluid.

11. An engine as defined in claim 9, wherein said temperature adjusting device comprises a temperature sensor for detecting a temperature in said casing, a cooler for cooling said culture fluid, a heater for heating said culture fluid, and a microprocessor programmed to control said cooler and said heater based on the temperature in said casing.

12. An engine as defined in claim 6, wherein said reaction purifier comprises a reservoir tank for collecting said culture fluid, and said reservoir tank is provided with a centrifugal separator for separating said microorganism from the culture fluid.

13. An engine as defined in claim 6, wherein said reaction purifier comprises a reservoir tank for collecting said culture fluid, and said reservoir tank comprises a vacuum drier for vacuum drying said microorganism.

14. An engine as defined in claim 6, wherein said engine further comprises a mechanism for introducing atmospheric air into exhaust gas to be brought in contact with said microorganism.

15. An engine as defined in claim 6, wherein said microorganism is a microorganism which feeds on carbon dioxide in said exhaust gas.

16. An engine as defined in claim 15, wherein said microorganism is a microorganism which feeds on carbon dioxide to regenerate fuel.

17. An engine as defined in claim 16, wherein said microorganism is a microorganism of the type HD-1.

18. An engine as defined in claim 6, wherein said microorganism is a microorganism which feeds on nitrogen oxides in said exhaust gas.

19. An engine as defined in claim 6, wherein said microorganism is a microorganism which feeds on hydrocarbons in said exhaust gas.

20. An engine as defined in claim 6, wherein said microorganism comprises Archaea.

21. An engine as defined in claim 6, wherein said microorganism comprises either one of Desulfurolobus and Acidianus.

22. An engine as defined in claim 6, wherein said microorganism is mixed with a culture fluid containing water and yeast extract.

23. An engine as defined in claim 22, wherein said culture fluid further comprises ammonium sulfate and sulfuric acid.

24. An engine as defined in claim 23, wherein said culture fluid further comprises one of potassium dihydrogen phosphate, magnesium sulfate, calcium chloride, ferric chloride, manganese chloride, sodium tetraborate, sulfur and calcium carbonate.

25. An engine as defined in claim 6, wherein said microorganism is a microorganism which is activated in a temperature range of 70-120°

C.

26. An engine as defined in claim 6, wherein said microorganism is mixed with a culture fluid having a pH value of 4.0 or less.

27. An engine as defined in claim 6, wherein said microorganism comprises an Alcaligenes microorganism.

28. An engine as defined in claim 27, wherein said Alcaligenes microorganism is mixed with a culture fluid containing water, peptone, meat extract, and sodium chloride.

29. An engine as defined in claim 27, wherein said Alcaligenes microorganism is mixed with a culture fluid containing water, blood agar and rabbit blood.

30. An engine as defined in claim 27, wherein said Alcaligenes microorganism is mixed with a culture fluid maintained in a temperature range of 20-40°

C.

31. An engine as defined in claim 27, wherein said Alcaligenes microorganism is mixed with a culture fluid having a pH value in the range of 5.0-8.0.

32. An engine as defined in claim 6, wherein said microorganism feeds on either one of sulfur gas and gaseous sulfur compounds in said exhaust gas.

33. An engine as defined in claim 6, wherein said exhaust gas passage comprises a branched exhaust pipe comprising a branch pipe for leading said exhaust gas into said reaction purifier and a branch pipe for bypassing said reaction purifier to lead said exhaust gas into the atmosphere, and valves for selectively leading said exhaust gas into said two branch pipes.

34. An engine as defined in claim 33 wherein said engine comprises a catalytic converter having a noble metal catalyst for purifying exhaust gas installed in said exhaust gas passage.

35. An engine as defined in claim 6, wherein said engine is an engine which uses gasoline as fuel.

36. An engine as defined in claim 35, wherein said engine is an engine which burns gasoline and air at an air-fuel ratio leaner than the stoichiometric air-fuel ratio.

37. An engine as defined in claim 35, wherein said engine is an engine which burns gasoline and air compressed within a range not exceeding a compression ratio of thirteen.

38. An engine as defined in claim 6, wherein said engine further comprises a catalytic converter having a noble metal catalyst for purifying exhaust gas installed in said passage, and said reaction purifier is arranged downstream of said catalytic converter in said passage.

39. An engine as defined in claim 6, wherein said engine is an engine which uses diesel oil as fuel.

40. An engine as defined in claim 39, wherein said engine is an engine which burns diesel oil and air compressed within a range not exceeding a compression ratio of twenty.

41. An engine as defined in claim 6, wherein said engine is an engine which burns hydrogen gas as fuel, and said microorganism feeds on either nitrogen oxides or hydrogen in said exhaust gas.

42. An engine as defined in claim 6, wherein said microorganism comprises an enzyme in a living organism.

43. An engine as defined in claim 42, wherein said enzyme in a living organism is an enzyme which removes carbon dioxide in exhaust gas.

44. An engine as defined in claim 42, wherein said enzyme in a living organism is an enzyme which removes carbon monoxide in exhaust gas.

45. An engine as defined in claim 42, wherein said enzyme in a living organism comprises hemoglobin.

46. An engine as defined in claim 6, wherein said enzyme in a living organism comprises cytochrome enzyme.

47. An engine as defined in claim 6, wherein said engine comprises a gas turbine.

48. An engine as defined in claim 6, wherein said engine further comprises a catalytic converter having a noble metal catalyst for purifying exhaust gas installed in said passage, and said reaction purifier is arranged in a passage leading from said combustion chamber to said catalytic converter.