Hydrogen enriched natural gas as a motor fuel with variable air fuel ratio and fuel mixture ratio control

• US 5,666,923 A
• Filed: 04/25/1995
• Issued: 09/16/1997
• Est. Priority Date: 05/04/1994
• Status: Expired due to Term

• Current Assignee: University of Central Florida (State University System of Florida), Voice It Technologies Worldwide, Inc.
• Original Assignee: University of Central Florida (State University System of Florida)
• Inventors: Mulligan, David Neal, Hahn, Douglas Edward, Hoekstra, Robert Louis, Collier, Robert Kirk Jr.
• Primary Examiner(s): Solis, Erick R.
• Application Number:
  US08/428,626
• Time in Patent Office: 875 Days
• Field of Search: 123/527, 123/27 GE, 123/3, 123/DIG. 12, 123/488, 48/199 FM
• US Class Current: 123/488
• CPC Class Codes: C10L 3/06 Natural gas; Synthetic natural gas obtained by processes not covered by C10G, C10K3/02 or C10K3/04 liquefying by pressure and cold treatment F25J
• CPC Class Codes: F02B 43/04 for improving efficiency of combustion
• CPC Class Codes: F02B 43/10 Engines or plants characterised by use of other specific gases, e.g. acetylene, oxyhydrogen
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels
• CPC Class Codes: Y10S 123/12 Hydrogen

Abstract

A hydrogen and natural gas fuel mixture for internal combustion engines is provided for vehicle engines such as those used in standard production engines for automobiles, trains and lawn mowers. The gaseous fuel for operating a vehicle combustion engines includes approximately 21 to 50% Hydrogen and the rest natural gas constituents such as combinations of Methane, Carbon Dioxide, Nitrogen, Ethane, Propane, Iso-Butane, N-Butane, Iso Pentane, N-Pentane, and Hexanes Plus. A fuel mixture of approximately 28 to 36 percent Hydrogen and a air fuel equivalence ratio of approximately 0.625 is an extreme lean burn condition that yields hydrocarbon emission levels of less than approximately 104 ppm (0.84 hm/hp hr.). Current internal combustion engines that are in mass production can take this alternative fuel without any substantial modifications to their systems. This alternative fuel is lean burning and emits emissions that are below current legal standards. The novel fuel mixture can be used in internal combustion engines for automobiles, lawnmowers, and trains. A control system for allowing the internal combustion engines to operate at extreme lean burn conditions is also provided for use with both a carburetor and fuel injection system. For a carburetor system, a secondary demand regulator system can kick in when a throttle is wide open and will allow additional fuel to pass through the system to meet instantaneous power demands such that occur when full throttle depression is insufficient for severe grade climbing, expressway merging, passing and the like. The fuel injection system can also be programed with a control algorithm that will select air fuel ratios. The computer control can increase fuel with respect to air when the throttle reaches a selected point of travel. The computer control can also dynamically change the hydrogen and natural gas fuel mixture ratio dynamically while the vehicle is being operated based on engine power demands and emissions.

Claims

1. A method for producing lean burn (below stoichometric) and low NOx emission rates for an internal combustion engine of a mobile vehicle using an alternative hydrogen and natural gas mixed fuel to achieve a lean burn (below stoichometric) without regard to the burn and emission rates of gasoline, comprising the steps of:

feeding an alternative gaseous fuel mixture of greater than 21% up to approximately 50% hydrogen gas, and the remainder being natural gas to an internal combustion engine of a mobile vehicle; and

operating the internal combustion engine at lean burn having an air and fuel equivalence ratio of approximately 0.6; and

emitting near zero NOx emissions below approximately 104 ppm (0.84 gm/hp hr), without misfiring the engine.

2. The method of claim 1, wherein the natural gas further includes at least one constituent selected from:

Methane, Carbon Dioxide, Nitrogen, Ethane, Propane, Iso-Butane, N-Butane, Iso Pentane, N-Pentane, and Hexanes Plus.

3. The method of claim 2, wherein the hydrogen gas in the mixture includes:

approximately twenty-eight (28) to approximately forty-two (42) percent hydrogen.

4. The method of claim 1, wherein the mobile vehicle engine further includes:

running an automobile.

5. The method of claim 1, wherein the mobile vehicle engine further includes:

running a lawn mower.

6. The method of claim 1, wherein the mobile vehicle engine further includes:

running a train.

7. The method of claim 1, wherein the operating step further includes:

operating at an air and fuel equivalence ratio of approximately 0.6.

8. A method for producing lean burn (below stiochometric) and low NOx emission rates for an internal combustion engine of a mobile vehicle using an alternative hydrogen and natural gas mixed fuel to achieve a lean burn condition (below stoichometric) without regard to the burn and emission rates of gasoline, comprising the steps of:

feeding an alternative gaseous fuel mixture of approximately 28 to approximately 50% hydrogen gas and the remainder being natural gas to an internal combustion engine of a mobile vehicle; and

operating the vehicle engine at an air and fuel equivalence ratio of less than 1.0 (stoichometric); and

emitting near zero NOx emissions from the vehicle engine to achieve a lean burn without misfiring the engine.

9. The method of claim 8, wherein the emitting step further includes:

emitting hydrocarbon emission levels of less than approximately 104 ppm (0.84 gm/hp hr).

10. The method of claim 8, wherein the fuel mixture includes:

approximately 28 to approximately 42% hydrogen gas and the remainder being natural gas.

11. The method of claim 8, wherein the operating step further includes:

operating the vehicle engine at an air and fuel equivalence ratio of approximately 0.6.