Bi-fuel control system and assembly for reciprocating diesel engine powered electric generators

• US 6,250,260 B1
• Filed: 10/13/1998
• Issued: 06/26/2001
• Est. Priority Date: 10/13/1998
• Status: Expired due to Term

• Current Assignee: Altronic LLC
• Original Assignee: Jason E. Green
• Inventors: Green, Jason E.
• Primary Examiner(s): Kamen, Noah P.
• Assistant Examiner(s): HUYNH, HAI H
• Application Number:
  US09/170,700
• Time in Patent Office: 987 Days
• Field of Search: 123/3, 123/27.GE, 123/525, 123/526, 123/575, 123/577, 123/578
• US Class Current: 123/27.0GE
• CPC Class Codes: F02B 2075/025 two
• CPC Class Codes: F02B 2201/064 Liquid and gas
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02B 43/00 Engines characterised by operating on gaseous fuels; Plants including such engines engines characterised by the gas-air charge being ignited by compression ignition of an additional fuel F02B7/06; engines convertible from gas to other fuel consumption F02B69/04
• CPC Class Codes: F02B 45/10 operating on mixtures of liquid and non-liquid fuels, e.g. in pasty or foamed state
• CPC Class Codes: F02B 63/04 for electric generators
• CPC Class Codes: F02D 19/023 to adjust the fuel mass or volume flow
• CPC Class Codes: F02D 19/027 Determining the fuel pressure, temperature or volume flow, the fuel tank fill level or a valve position
• CPC Class Codes: F02D 19/105 operating in a special mode, e.g. in a liquid fuel only mode for starting
• CPC Class Codes: F02D 29/06 peculiar to engines driving electric generators
• CPC Class Codes: F02M 21/047 Venturi mixer
• CPC Class Codes: F02M 23/03 the secondary air-valve controlled by main combustion-air throttle
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

A system and assembly for modifying a diesel powered electric generator preferably of the reciprocating engine type to the extent that the generator is capable of running on either 100% diesel fuel or in a “bi-fuel” mode which is defined as a mixture of methane based gas and diesel fuel. The system and associated assembly is specifically designed to provide for the automatic or manual switching between the full diesel mode and the gas-diesel fuel or bi-fuel mode for continuous generator operation without interruption in generator output and at substantially equivalent or comparable efficiency levels. A gas control sub-assembly is included for controlling the amount of gas supplied to the driving engine of the generator while operating in the bi-fuel mode, a diesel control sub-assembly is included and designed for controlling the amount of diesel fuel supply to the driving engine while operating in the bi-fuel mode, and an electronic control an monitoring sub-assembly is included and designed for controlling various components of the overall system and is further structured to monitor and display certain data associated with operation and continuous current output within pre-determined, acceptable parameters.

Claims

1. A system for modifying diesel powered electric generators so as to be operated either in a full diesel fuel mode or a gas-diesel fuel mode, at substantially equivalent operating efficiencies, said system comprising:

a) a gas control sub-system designed to control the amount of gas supplied to a driving engine of the generator while being operated in the gas-diesel fuel mode,

b) a diesel control sub-system designed to control the amount of diesel fuel supplied to the driving engine while being operated in the gas-diesel fuel mode,

c) an electronic control sub-system designed to regulate operation of pre-determined components of the gas control sub-system and the diesel control sub-system, and

d) the gas control sub-system, the diesel control sub-system and the electronic control sub-system being collectively interdependent so as to allow a change of operation of the generator between the full diesel fuel mode and the gas-diesel fuel mode without generator power output being interrupted; and

e) the gas control sub-system structured to permit the amount of gas supplied to the driving engine to be determined in response to the load requirements of the driving engine, and at least said gas control sub-system operating independently from a governor of the diesel engine; and

f) said electronic control sub-system further structured to determine load levels through the monitoring of the driving engine'"'"'s manifold air pressure.

2. A system as in claim 1 wherein the change of operation of the generator between the gas-diesel fuel mode and the full diesel fuel mode is accomplished either automatically or manually.

3. An assembly as recited in claim 2 wherein the gas control sub-system includes a manually regulatable flow of gas from a gas supply under a predetermined positive gas supply pressure.

4. A system as recited in claim 3 wherein the predetermined gas supply pressure is generally between 1 psi and 5 psi.

5. A system as recited in claim 4 wherein the gas control sub-system is further designed to regulate gas pressure by reducing the predetermined gas supply pressure to atmospheric pressure so as to allow continued gas flow to the driving engine substantially only on a demand basis.

6. A system as recited in claim 5 wherein a gas flow requirement to the driving engine is dependent on a driving engine vacuum created by a driving engine intake air flow.

7. A system as recited in claim 6 wherein the gas control sub-system is further designed to regulate gas flow and to have separate gas flow rates for light to medium generator load levels and for medium to heavy generator load levels.

8. A system as recited in claim 7 wherein the separate gas flow rates are adjustable and preset for operation over a wide spectrum of load levels.

9. A system as recited in claim 3 wherein the gas control sub-system is designed to monitor the predetermined gas supply pressure and automatically switch from the gas-diesel fuel mode to the full diesel fuel mode if the predetermined gas supply pressure drops below a specified set point.

10. A system as recited in claim 9 wherein the gas control sub-system is further designed to automatically switch back from the full diesel fuel mode to the gas-diesel fuel mode when the predetermined gas pressure rises above the specified set point.

11. A system as recited in claim 2 wherein the gas control sub-system is further designed to stop gas flow to the driving engine during the gas-diesel fuel mode in the event of a shut down of the system or a shut down of the generator.

12. A system as recited in claim 11 wherein the gas control sub-system is further designed to stop gas flow to the driving engine during the gas-diesel fuel mode during either automatic or manual shut down of the system.

13. A system as recited in claim 12 wherein the gas control sub-system is structured to stop gas flow to the driving engine at a location in the gas control sub-system which will ensure gas flow does not reach the driving engine during a period of operation in the full diesel fuel mode.

14. A system as recited in claim 2 wherein the gas control sub-system is structured to pre-set a maximum gas flow rate to the driving engine independent of load requirements of the generator.

15. A system as recited in claim 2 wherein the gas control sub-system is further structured to mix engine intake air and gas upstream of the driving engine air intake system on a demand basis without incorporating an air throttling function.

16. A system as recited in claim 2 wherein said gas control sub-system is structured to be scaleable.

17. A system as recited in claim 2 wherein the diesel control sub-system is further structured to selectively restrict the flow of diesel fuel supply to the driving engine and allow for a substitution of an air gas mixture during the gas-diesel fuel mode of operation.

18. A system as recited in claim 17 wherein the diesel control sub-system is structured to permit manual adjustment of the flow of diesel fuel.

19. A system as recited in claim 17 wherein the diesel control sub-system further includes a secondary adjustment of the flow of diesel fuel dependent on load requirements of the generator being light to medium or medium to heavy.

20. A system as recited in claim 19 wherein the electronic control sub-system determines the secondary adjustment by determining the load levels through the monitoring of generator amperage output levels.

21. A system as recited in claim 19 wherein the electronic control sub-system determines the secondary adjustment by determining the load levels through the monitoring of generator kilowatt output.

22. A system as recited in claim 19 wherein the diesel control sub-system is structured to automatically restore 100% intended diesel fuel flow to the driving engine when the generator is in the full diesel fuel mode.

23. A system as recited in claim 22 wherein the diesel control sub-system will relieve back pressure in a diesel fuel flow path by diverting diesel fuel flow back to a diesel fuel supply upon fuel back pressure reaching a predetermined level.

24. A system as recited in claim 2 wherein said diesel control sub-system is structured to be scaleable.

25. A system as recited in claim 2 wherein the electronic control sub-system is further designed to monitor and display predetermined operating parameters of the gas control system, the diesel control system and the driving engine.

26. A system as recited in claim 25 wherein the electronic control system is further designed to cease operation in the gas diesel fuel mode upon a monitored indication of low oil pressure of the driving engine.

27. A system as recited in claim 26 wherein the electronic control system is further designed to cease operation in the gas diesel fuel mode upon a monitor indication of low gas pressure.

28. A system as recited in claim 25 wherein the electronic control sub-system is further designed to automatically cease operation in the gas-diesel fuel mode and begin operation in the full diesel fuel mode upon an exhaust gas temperature of the driving engine exceeding a predetermined temperature range.

29. A system as recited in claim 28 wherein the predetermined temperature range of the exhaust gas temperature comprises a manually adjustable set point.

30. A system as recited in claim 28 wherein the exhaust gas temperature in a generator having a dual exhaust system is determined by independently monitoring the exhaust gas temperature of each exhaust of the dual exhaust system.

31. A system as recited in claim 28 wherein the electronic control sub-system structured to permit a resumption to operation in the gas-diesel fuel mode, subsequent to automatically ceased operation due to said exhaust gas temperature of the driving engine exceeding said predetermined temperature range, only upon manual re-activation subsequent to a monitored display of the exhaust gas temperature within the predetermined temperature range.

32. A system as recited in claim 28 wherein the electronic control sub-system is further designed to initially monitor electric current input and to regulate both gas flow and diesel fuel flow dependent on electric current input relative to a first adjustable set point and a second adjustable set point.

33. A system as recited in claim 32 wherein the first adjustable set point comprises a low current cut-off set point below which operation will automatically cease in the gas-diesel fuel mode and begin in the full diesel fuel mode.

34. A system as recited in claim 32 wherein the second adjustable set point comprises a light to medium load set point below which operation of the gas-diesel fuel mode will continue.

35. A system as recited in claim 34 wherein the electronic control sub-system is further designed to secondarily monitor received electric current input for safe guarding against overloading of the generator beyond intended service limits by automatically ceasing operation in the gas-diesel fuel mode and beginning operation in the full diesel fuel mode.

36. A system as recited in claim 35 wherein the electronic control sub-system is further designed to include an adjustable time delay function allowing short duration generator load deviation to be ignored and thereby preventing resulting on-off cycling between operation in the gas-diesel fuel mode and full diesel fuel mode.

37. A system as recited in claim 2 further comprising a master time delay designed to delay initiation of operation in the gas-diesel fuel mode for an adjustable, pre-set time period to accommodate paralleling operations with one or more additional generators or an electric utility grid.

38. A system as in claim 1 wherein the operation of the generator in the gas-diesel fuel mode is at least partially defined by operation of the generator at a predetermined mixture of methane based gas and diesel fuel.

39. A system as recited in claim 38 wherein the quantity gas utilized in the gas-diesel fuel mode of operation of the generator is generally between 40% to 90% of the total fuel consumed by the driving engine during operation in the gas-diesel fuel mode.

40. An assembly designed to modify a diesel powered electric generator so as to be operable in either a gas-diesel fuel mode or a full diesel fuel mode at comparable operating efficiencies, said assembly comprising:

a) a gas control sub-assembly structured to control the amount of gas supplied to a driving engine of the generator during operation in the gas-diesel fuel mode,

b) a diesel control sub-assembly structured to control the amount of diesel fuel supplied to the driving engine while being operated in the gas-diesel fuel mode,

c) an electronic control sub-assembly structured to at least partially regulate operation of said gas control sub-assembly and said diesel control sub-assembly, and

d) said gas control sub-assembly, said diesel control sub-assembly and said electronic control sub-assembly being cooperatively structured to provide both automatic and manual changes of operation of the generator between the gas-diesel fuel mode and the full diesel fuel mode without disruption of generator power output,

e) said gas control sub-assembly further including a gas pressure regulator, and

f) said gas pressure regulator structured to utilize a demand control for gas flow, said demand control defined by the vacuum generated by an intake air flow of the driving engine.

41. An assembly as recited in claim 40 structured to operate on a predetermined mixture of methane based gas fuel and diesel fuel during operation of the generator in the gas-diesel fuel mode.

42. An assembly as recited in claim 41 wherein said predetermined mixture of methane based gas fuel comprises substantially 40% to 90% of the total fuel consumed during operation in the gas-diesel fuel mode.

43. An assembly as recited in claim 42 wherein said gas control sub-assembly comprises a main shut-off valve disposed to regulate gas flow under positive pressure from a gas supply.

44. An assembly as recited in claim 43 wherein said gas control sub-assembly further comprises a gas pressure sensor disposed down stream of said main shut-off valve and structured to switch operation from the gas-diesel fuel mode to the full diesel fuel mode when gas pressure drops below a predetermined pressure and automatically switch operation back to the gas-diesel fuel mode upon restoration of the gas pressure to at least said predetermined pressure.

45. An assembly as recited in claim 44 wherein said gas control sub-assembly further comprises a solenoid valve disposed down stream of said gas pressure sensor and structured to automatically stop gas flow to the driving engine upon shut down of the assembly or the generator.

46. An assembly as recited in claim 45 wherein said solenoid valve is disposed and structured to ensure stoppage of positive pressure gas flow into the driving engine.

47. An assembly as recited in claim 45 wherein said gas control sub-assembly further comprises said gas pressure regulator disposed down stream of said solenoid valve and structured to reduce positive gas pressure so as to require a vacuum to be present at an outlet of said gas pressure regulator in order to generate gas flow to the driving engine.

48. An assembly as recited in claim 47 wherein said gas control sub-assembly further comprises a gas control valve located down stream of said gas pressure regulator and structured to control gas flow dependent on the generator load demand being light to medium or medium to heavy.

49. An assembly as recited in claim 48 wherein said gas control valve comprises a butterfly valve structured to assume a substantially fully opened, de-energized position during medium to heavy load demands and a partially opened positioned during light to medium load demands.

50. An assembly as recited in claim 48 wherein said gas control valve is adjustably positionable into a plurality of orientations.

51. An assembly as recited in claim 48 wherein said gas control sub-assembly further comprises a gas power valve located down stream of said gas control valve and structured to determine a maximum rate of gas flow to the driving engine during operation in the gas-diesel fuel mode.

52. An assembly as recited in claim 51 wherein said gas power valve comprises an adjustable needle valve structured to be pre-set in a fixed position to determine the maximum rate of gas flow independent of generator load demands.

53. An assembly as recited in claim 51 wherein said gas control sub-assembly further comprises an air-fuel mixing device located in fluid communication with the gas flow, down stream of said gas power valve and up stream of an air intake of the driving engine, said air-fuel mixing device further disposed and structured to funnel all incoming air therethrough prior to reaching the air intake system of the driving engine.

54. An assembly as recited in claim 53 wherein said air-fuel mixing device comprises a fixed venturi further disposed and structured to deliver an air-gas homogeneous mixture to the engine air intake manifold absent any throttling function.

55. An assembly as recited in claim 41 wherein said diesel control sub-assembly comprises a diesel fuel control valve disposed within the generator fuel system and structured to significantly restrict flow of diesel fuel to the driving engine during operation in the gas-diesel fuel mode, said diesel fuel control valve being further structured to restore normal diesel fuel flow during operation in the full diesel fuel mode.

56. An assembly as recited in claim 55 wherein said diesel fuel control valve comprises at least one manually adjustable, internal needle valve.

57. An assembly as recited in claim 56 wherein said diesel fuel control valve further comprises a secondary internal needle valve structured to provide fine adjustment of the flow of diesel fuel during both light to medium load demands and medium to heavy load demands of the generator.

58. An assembly as recited in claim 55 wherein said diesel control sub-assembly is structured to relieve fuel back pressure on an inlet side of said diesel fuel control valve by diverting flow of diesel fuel from said diesel fuel control valve to a diesel fuel supply upon fuel back pressure resulting from a restricted flow at said diesel fuel control valve reaching a predetermined point.

59. An assembly as recited in claim 41 wherein said electronic control sub-assembly is further structured to monitor predetermined engine parameters and display system data to a user.

60. An assembly as recited in claim 59 wherein said electronic control sub-assembly further comprises an oil pressure switch structured to automatically assume an opened position upon a detection of a predetermined low oil pressure and thereby cease operation in the gas-diesel fuel mode.

61. An assembly as recited in claim 60 wherein said electronic control sub-assembly further comprises a gas pressure switch structured to automatically assume an opened position upon a detection of a predetermined low gas pressure and thereby cease operation in the gas-diesel fuel mode.

62. An assembly as recited in claim 61 wherein said electronic control sub-assembly further comprises an engine exhaust gas temperature monitor assembly structured to automatically cease operation in the gas-diesel fuel mode and begin operation in the full diesel fuel mode upon the engine exhaust gas temperature exceeding a predetermined temperature.

63. An assembly as recited in claim 62 wherein said electronic control sub-assembly comprises a manual exhaust gas temperature reset switch structured to transfer operation from the full diesel fuel mode to the gas-diesel fuel mode upon a monitored indication of the engine exhaust gas temperature assuming a predetermined acceptable level.

64. An assembly as recited in claim 63 wherein said electronic control sub-assembly further comprises a first current relay assembly and a second current relay assembly;

said first current relay assembly structured to include adjustable first and second set points and further structured to regulate gas and diesel flow during operation in the gas-diesel fuel mode.

65. An assembly as recited in claim 64 wherein said first set point defines a low current cut off set point below which operation will switch from the gas-diesel fuel mode to the full diesel fuel mode.

66. An assembly as recited in claim 64 wherein said second set point defines a light to medium load demand set point for activating gas flow and said diesel fuel flow when operating in the gas-diesel fuel mode.

67. An assembly as recited in claim 66 wherein said second current relay assembly is structure to switch operation from the gas-diesel fuel mode to the full diesel fuel mode when generator load demands exceed predetermined pre-set limits.

68. An assembly as recited in claim 67 wherein said first relay assembly further comprises an adjustable time delay set point structured to ignore short duration generator load deviations and prevent cycling between light to medium load fuel settings and medium to heavy load fuel settings during operation in the gas-diesel fuel mode.

69. An assembly as in claim 67 wherein said second relay assembly further comprises an adjustable time delay set point structured to ignore short duration generator load deviations and prevent associated on-off cycling between operation in the gas-diesel fuel mode and the full diesel fuel mode.

70. An assembly as recited in claim 41 further comprising a master time relay structured to automatically delay initiation of operation in the gas diesel fuel mode for a predetermined time period until the generator while operating in a full diesel fuel mode has completed paralleling functions.

71. A system for modifying diesel powered electric generators so as to be operated either in a full diesel fuel mode or a gas-diesel fuel mode, at substantially equivalent operating efficiencies, said system comprising:

a) a gas control sub-system designed to control the amount of gas supplied to a driving engine of the generator while being operated in the gas-diesel fuel mode,

b) a diesel control sub-system designed to control the amount of diesel fuel supplied to the driving engine while being operated in the gas-diesel fuel mode,

c) an electronic control sub-system designed to regulate operation of pre-determined components of the gas control sub-system and the diesel control sub-system, and

d) the gas control sub-system, the diesel control sub-system and the electronic control sub-system being collectively interdependent so as to allow a change of operation of the generator between the full diesel fuel mode and the gas-diesel fuel mode without generator power output being interrupted;

e) the gas control sub-system structured to permit the amount of gas supplied to the driving engine to be determined in response to the load requirements of the driving engine, ad at least said gas control sub-system operating independently from a governor of the diesel engine; and

f) the electronic control system is further structured to cease operation in the gas diesel fuel mode upon a monitored indication of low oil pressure of the driving engine.

72. A system for modifying diesel powered electric generators so as to be operated either in a full diesel fuel mode or a gas-diesel fuel mode, at substantially equivalent operating efficiencies, said system comprising:

a) a gas control sub-system designed to control the amount of gas supplied to a driving engine of the generator while being operated in the gas-diesel fuel mode,

b) a diesel control sub-system designed to control the amount of diesel fuel supplied to the driving engine while being operated in the gas-diesel fuel mode,

c) an electronic control sub-system designed to regulate operation of pre-determined components of the gas control sub-system and the diesel control sub-system, and

d) the gas control sub-system, the diesel control sub-system and the electronic control sub-system being collectively interdependent so as to allow a change of operation of the generator between the full diesel fuel mode and the gas-diesel fuel mode without generator power output being interrupted;

e) the gas control sub-system structured to permit the amount of gas supplied to the driving engine to be determined in response to the load requirements of the driving engine, ad at least said gas control sub-system operating independently from a governor of the diesel engine; and

f) the electronic control sub-system is further structured to automatically cease operation in the gas-diesel fuel mode and begin operation in the full diesel fuel mode upon an exhaust gas temperature of the driving engine exceeding a predetermined temperature range, the exhaust gas temperature in a generator having a dual exhaust system is determined by independently monitoring the exhaust gas temperature of each exhaust of the dual exhaust system.

73. A system for modifying diesel powered electric generators so as to be operated either in a full diesel fuel mode or a gas-diesel fuel mode, at substantially equivalent operating efficiencies, said system comprising:

a) a gas control sub-system designed to control the amount of gas supplied to a driving engine of the generator while being operated in the gas-diesel fuel mode,

b) a diesel control sub-system designed to control the amount of diesel fuel supplied to the driving engine while being operated in the gas-diesel fuel mode,

c) an electronic control sub-system designed to regulate operation of pre-determined components of the gas control sub-system and the diesel control sub-system, and

d) the gas control sub-system, the diesel control sub-system and the electronic control sub-system being collectively interdependent so as to allow a change of operation of the generator between the full diesel fuel mode and the gas-diesel fuel mode without generator power output being interrupted;

e) the gas control sub-system structured to permit the amount of gas supplied to the driving engine to be determined in response to the load requirements of the driving engine, ad at least said gas control sub-system operating independently from a governor of the diesel engine; and

f) the electronic control sub-system is further structured to include an adjustable time delay function allowing short duration generator load deviation to be ignored and thereby preventing resulting on-off cycling between operation in the gas-diesel fuel mode and full diesel fuel mode.

74. A system for modifying diesel powered electric generators so as to be operated either in a full diesel fuel mode or a gas-diesel fuel mode, at substantially equivalent operating efficiencies, said system comprising:

a) a gas control sub-system designed to control the amount of gas supplied to a driving engine of the generator while being operated in the gas-diesel fuel mode,

b) a diesel control sub-system designed to control the amount of diesel fuel supplied to the driving engine while being operated in the gas-diesel fuel mode,

c) an electronic control sub-system designed to regulate operation of pre-determined components of the gas control sub-system and the diesel control sub-system, and

d) the gas control sub-system, the diesel control sub-system and the electronic control sub-system being collectively interdependent so as to allow a change of operation of the generator between the full diesel fuel mode and the gas-diesel fuel mode without generator power output being interrupted;

e) the gas control sub-system structured to permit the amount of gas supplied to the driving engine to be determined in response to the load requirements of the driving engine, ad at least said gas control sub-system operating independently from a governor of the diesel engine; and

f) a master time delay structured to delay initiation of operation in the gas-diesel fuel mode for an adjustable, pre-set time period to accommodate paralleling operations with one or more additional generators or an electric utility grid.

75. An assembly designed to modify a diesel powered electric generator so as to be operable in either a gas-diesel fuel mode or a full diesel fuel mode at comparable operating efficiencies, said assembly comprising:

a) a gas control sub-assembly structured to control the amount of gas supplied to a driving engine of the generator during operation in the gas-diesel fuel mode,

b) a diesel control sub-assembly structured to control the amount of diesel fuel supplied to the driving engine while being operated in the gas-diesel fuel mode,

c) an electronic control sub-assembly structured to at least partially regulate operation of said gas control sub-assembly and said diesel control sub-assembly,

d) said gas control sub-assembly, said diesel control sub-assembly and said electronic control sub-assembly being cooperatively structured to provide both automatic and manual changes of operation of the generator between the gas-diesel fuel mode and the full diesel fuel mode without disruption of generator power output,

e) said diesel control sub-assembly further including a diesel fuel control valve, and

f) said diesel fuel control valve including at least one manually adjustable, internal needle valve.

76. An assembly designed to modify a diesel powered electric generator so as to be operable in either a gas-diesel fuel mode or a full diesel fuel mode at comparable operating efficiencies, said assembly comprising:

a) a gas control sub-assembly structured to control the amount of gas supplied to a driving engine of the generator during operation in the gas-diesel fuel mode,

b) a diesel control sub-assembly structured to control the amount of diesel fuel supplied to the driving engine while being operated in the gas-diesel fuel mode,

c) an electronic control sub-assembly structured to at least partially regulate operation of said gas control sub-assembly and said diesel control sub-assembly,

d) said gas control sub-assembly, said diesel control sub-assembly and said electronic control sub-assembly being cooperatively structured to provide both automatic and manual changes of operation of the generator between the gas-diesel fuel mode and the full diesel fuel mode without disruption of generator power output,

e) said diesel control sub-assembly further including a diesel fuel control valve, and

f) said diesel control sub-assembly further structured to relieve fuel back pressure on an inlet side of said diesel fuel control valve by diverting flow of diesel fuel from said diesel fuel control valve to a diesel fuel supply upon fuel back pressure resulting from a restricted flow at said diesel fuel control valve reaching a predetermined point.

77. An assembly designed to modify a diesel powered electric generator so as to be operable in either a gas-diesel fuel mode or a full diesel fuel mode at comparable operating efficiencies, said assembly comprising:

a) a gas control sub-assembly structured to control the amount of gas supplied to a driving engine of the generator during operation in the gas-diesel fuel mode,

b) a diesel control sub-assembly structured to control the amount of diesel fuel supplied to the driving engine while being operated in the gas-diesel fuel mode,

c) an electronic control sub-assembly structured to at least partially regulate operation of said gas control sub-assembly and said diesel control sub-assembly,

d) said gas control sub-assembly, said diesel control sub-assembly and said electronic control sub-assembly being cooperatively structured to provide both automatic and manual changes of operation of the generator between the gas-diesel fuel mode and the full diesel fuel mode without disruption of generator power output, and

f) said electronic control sub-assembly further including an oil pressure switch structured to automatically assume an opened position upon a detection of a predetermined low oil pressure and thereby cease operation in the gas-diesel fuel mode.