Fuel management system for variable ethanol octane enhancehment of gasoline engines

• US 20060102145A1
• Filed: 11/18/2004
• Published: 05/18/2006
• Est. Priority Date: 11/18/2004
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Bromberg, Leslie, Cohn, Daniel R., Heywood, John B.
• Granted Patent: US 7,314,033 B2
• Time in Patent Office: Days
• US Class Current: 123/406.290
• CPC Class Codes: F02B 17/00 Engines characterised by means for effecting stratification of charge in cylinders
• CPC Class Codes: F02B 17/005 having direct injection in the combustion chamber
• CPC Class Codes: F02B 47/00 Methods of operating engines involving adding non-fuel substances or anti-knock agents to combustion air, fuel, or fuel-air mixtures of engines
• CPC Class Codes: F02B 47/04 the substances being other than water or steam only
• CPC Class Codes: F02B 51/00 Other methods of operating engines involving pretreating of, or adding substances to, combustion air, fuel, or fuel-air mixture of the engines
• CPC Class Codes: F02B 7/00 Engines characterised by the fuel-air charge being ignited by compression ignition of an additional fuel characterised by both fuel-air mixture compression and air compression, or characterised by both positive ignition and compression ignition F02B11/00
• CPC Class Codes: F02D 19/08 simultaneously using pluralities of fuels F02D19/12 takes precedence
• CPC Class Codes: F02D 19/081 Adjusting the fuel composition or mixing ratio; Transitioning from one fuel to the other
• CPC Class Codes: F02D 2041/389 for injecting directly into the cylinder
• CPC Class Codes: F02D 2200/1002 Output torque
• CPC Class Codes: F02D 35/027 using knock sensors
• CPC Class Codes: F02D 41/0025 Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
• CPC Class Codes: F02D 41/3094 the fuel injection being effected by at least two different injectors, e.g. one in the intake manifold and one in the cylinder
• CPC Class Codes: F02M 25/00 Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding secondary air to fuel-air mixture F02M23/00; adding exhaust gases F02M26/00; fuel-injection apparatus operating simultaneously on two or more fuels or on a liquid fuel and another liquid F02M43/00
• CPC Class Codes: F02M 25/14 adding anti-knock agents, not provided for in subgroups F02M25/022 - F02M25/10
• CPC Class Codes: F02P 5/045 combined with electronic control of other engine functions, e.g. fuel injection in general F02D37/02
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Fuel management system for efficient operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder of the engine. A fuel management microprocessor system controls injection of the anti-knock agent so as to control knock and minimize that amount of the anti-knock agent that is used in a drive cycle. It is preferred that the anti-knock agent is ethanol. The use of ethanol can be further minimized by injection in a non-uniform manner within a cylinder. The ethanol injection suppresses knock so that higher compression ratio and/or engine downsizing from increased turbocharging or supercharging can be used to increase the efficiency of the engine.

Claims

1. Fuel management system for operation of a spark ignition gasoline engine comprising:

a gasoline engine;

a source of an anti-knock agent;

an injector for direct injection of the anti-knock agent into a cylinder of the engine; and

a fuel management control system for controlling injection of the anti-knock agent into the cylinder to control knock.

2. The system of claim 1 wherein the injectors deposit the anti-knock agent to provide non-uniform deposition within a cylinder.

3. The system of claim 2 wherein the anti-knock agent is deposited near the walls of the cylinder.

4. The system of claim 2 wherein the non-uniform deposition is obtained through direct injection and charge swirl.

5. The system of claim 1 wherein the anti-knock agent is selected from the group consisting of ethanol, methanol, tertiary butyl alcohol, MTBE, ETBE and TAME.

6. The system of claim 1 wherein the fuel management system includes a microprocessor that operates in an open loop fashion on a predetermined correlation between required octane number enhancement and fraction of fuel provided by the anti-knock agent.

7. The system of claim 1 wherein the gasoline engine includes a knock sensor providing a feedback signal to a fuel management microprocessor to minimize the amount of the anti-knock agent added to prevent knock in a closed loop fashion.

8. The system of claim 1 wherein the anti-knock agent is ethanol.

9. The system of claim 8 wherein the ethanol is mixed with water.

10. The system of claim 8 wherein the ethanol is mixed with a lubricant.

11. The system of claim 1 wherein the engine has substantial organized motion such as swirl.

12. The system of claim 1 wherein the system includes a measure of the amount of anti-knock agent in the source to control turbocharging, supercharging or spark retard when the amount of anti-knock agent is low.

13. The system of claim 1 wherein the anti-knock agent is added only during portions of a drive cycle requiring knock resistance.

14. The system of claim 1 wherein gasoline is port injected into the engine.

15. The system of claim 1 wherein the gasoline is directly injected into the cylinder.

16. The system of claim 8 wherein the direct injection of ethanol provides substantially a 13 °

C. drop in temperature for every 10% of fuel energy provided by the ethanol.

17. The system of claim 1 wherein the fuel management system substantially minimizes the amount of anti-knock agent used over a drive cycle.

18. The system of claim 8 wherein an octane enhancement of at least 4 octane numbers is obtained when 20% of the fuel energy in a cylinder comes from ethanol.

19. The system of claim 1 wherein turbocharging or supercharging are reduced or eliminated and/or spark retard is increased when the anti-knock agent is not available.

20. The system of claim 8 wherein ethanol is injected proximate to a cylinder wall and swirl creates a ring of ethanol.

24. The system of claim 8 wherein the engine is operated with substantially a stoichiometric air/fuel ratio.

25. The system of claim 8 wherein the ethanol is added only during portions of the drive cycle requiring knock resistance and its use is minimized during those times.

26. The system of claim 8 wherein the ethanol is separated from a gasoline/ethanol mixture.

27. The system of claim 8 wherein torque of the engine at which knock occurs can be increased by at least a factor of two by the direct injection of ethanol.

28. The system of claim 8 wherein horsepower of a given size engine can be at least doubled by using ethanol octane enhancement.

29. The system of claim 8 wherein gasoline consumption is reduced by at least 20% due to higher efficiency engine operation.

21-23. -23. (canceled)

30. Fuel management system for operation of a spark ignition gasoline engine comprising:

a gasoline engine;

a source of ethanol;

an injector for direct injection of the ethanol into a cylinder of the engine; and

a fuel management control system for controlling injection of the ethanol into the cylinder when engine torque is above a selected fraction of maximum torque.

31. The system of claim 30 wherein torque levels at which the ethanol is directly injected are those where knock would occur absent the ethanol injection.

32. The system of claim 30 wherein the fraction of total fuel provided by the directly injected ethanol increases with increasing torque.

33. The system of claim 30 wherein gasoline is port fuel injected.

34. The system of claim 30 wherein up to and including substantially 100% of the fuel can be provided by the ethanol.

35. The system of claim 30 wherein octane number is enhanced with increasing torque.

36. The system of claim 30 wherein an octane enhancement of more than 20 octane numbers is achieved.

37. The system of claim 30 wherein the fuel management system includes a microprocessor that operates in an open loop fashion on a predetermined correlation between the required octane number enhancement and fraction of fuel provided by the ethanol.

38. The system of claim 30 wherein the gasoline engine includes a knock sensor providing a feedback signal to a fuel management microprocessor to minimize the amount of the ethanol added to prevent knock in a closed loop fashion.

39. The system of claim 30 wherein the injector provides non-uniform deposition of the ethanol within a cylinder.

40. The system of claim 39 wherein the ethanol is deposited near the walls of the cylinder.

41. The system of claim 39 wherein the non-uniform deposition is obtained through direct injection and charge swirl.

42. The system of claim 30 wherein the ethanol is mixed with water.

43. The system of claim 30 wherein the ethanol is mixed with a lubricant.

44. The system of claim 30 wherein the engine has substantial organized motion such as swirl.

45. The system of claim 30 wherein the system includes a measure of the amount of ethanol available to control turbocharging, supercharging or spark retard when the amount of ethanol is low.

46. The system of claim 30 wherein the gasoline is directly injected into the cylinder.

47. The system of claim 30 wherein the direct injection of ethanol provides substantially a 13°

C. drop in temperature for every 10% of the fuel energy provided by the ethanol.

48. The system of claim 30 wherein the fuel management system substantially minimizes the amount of ethanol used over a drive cycle.

49. The system of claim 30 wherein an octane enhancement of at least four octane numbers is obtained when 20% of the fuel energy in a cylinder comes from ethanol.

50. The system of claim 30 wherein turbocharging or supercharging are reduced or eliminated and/or spark retard is increased when ethanol is not available.

51. The system of claim 30 wherein the engine is operated with substantially a stoichiometric fuel/air ratio.

52. The system of claim 30 wherein the ethanol is separated from a gasoline/ethanol mixture.

53. The system of claim 30 wherein the engine can be operated with only gasoline and knock can be avoided by reducing the maximum torque and horsepower relative to values when ethanol is directly injected into the cylinder.

54. The system of claim 53 wherein the horsepower is reduced by at least a factor of two.

55. The system of claim 30 wherein the fuel management microprocessor control system uses ethanol level in the ethanol tank as an input to control a turbocharger, supercharger or spark retard.

56. The system of claim 55 wherein the turbocharger, supercharger or spark retard is adjusted to prevent knock.