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

• US 5,787,864 A
• Filed: 12/21/1996
• Issued: 08/04/1998
• Est. Priority Date: 04/25/1995
• Status: Expired due to Term

• Current Assignee: University of Central Florida (State University System of Florida)
• 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:
  US08/771,647
• Time in Patent Office: 591 Days
• Field of Search: 123/527, 123/436, 123/683, 123/675, 123/443, 123/492
• US Class Current: 123/492
• CPC Class Codes: F02D 19/022 to adjust the fuel pressure, temperature or composition
• CPC Class Codes: F02D 19/0644 the gaseous fuel being hydrogen, ammonia or carbon monoxide
• CPC Class Codes: F02D 19/081 Adjusting the fuel composition or mixing ratio; Transitioning from one fuel to the other
• CPC Class Codes: F02M 21/0215 Mixtures of gaseous fuels; Natural gas; Biogas; Mine gas; Landfill gas
• 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 control system for varying air and fuel ratios of an internal combustion engines running at lean burn with reduced emissions during cycles for instantaneous power demands comprising:

an internal combustion engine of a mobile vehicle operating on a fuel supply having a mixture of hydrogen and natural gas;

an air fuel control for maintaining fuel supplied to the engine to remain at a selected air fuel ratio to achieve a lean burn condition;

a throttle for controlling the amount of fuel being supplied to the engine, the throttle having a closed position through a fully open position;

a sensor activated by the fully open position of the throttle, wherein the activated sensor causes the air fuel control to increase the percentage of fuel in the selected air fuel ratio; and

means for dynamically adjusting mixture ratios of the hydrogen gas and the natural gas supplied to the engine based on engine power and emission.

2. The control system of claim 1, wherein the fuel supply includes:

a mixture of approximately 21 to 50% hydrogen gas and the remainder being natural gas.

3. The control system of claim 1, wherein the fuel supply includes:

a mixture of approximately 28 to 36% hydrogen gas and the remainder being natural gas.

4. The control system of claim 1, wherein the air-fuel control includes:

a carburetor.

5. The control system of claim 1, wherein the air-fuel control includes:

a fuel injection control.

6. The control system of claim 1, where the selected air fuel ratio is controlled by:

engine speed, spark timing, air flow and throttle pedal position.

7. The control system of claim 6, wherein the selected air fuel ratio is further controlled by at least one of:

in-cylinder pressure, exhaust emissions and fuel flow.

8. A method for producing lean burn and low emission rates for an internal combustion engine of a mobile vehicle using a dynamically adjustable alternative fuel as compared to the burn and emission rates of gasoline fuel to achieve a lean burn, comprising the steps of:

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

operating the air fuel ratio of the vehicle to achieve a lean burn condition without misfiring the engine; and

means for dynamically adjusting mixture ratios of the hydrogen gas and the natural gas supplied to the engine based on engine power and emission.

9. A method for producing lean burn and low emission rates for an internal combustion engine of a mobile vehicle using a dynamically adjustable alternative fuel as compared to the burn and emission rates of gasoline fuel to achieve a lean burn condition, comprising the steps of:

feeding an alternative gaseous fuel mixture of approximately 28 to approximately 36% hydrogen gas and the remainder being natural gas to an internal combustion engine of a mobile vehicle;

operating the vehicle engine at an air and fuel equivalence ratio of approximately 0.625 to achieve a lean burn condition without misfiring the engine and

means for dynamically adjusting mixture ratios of the hydrogen gas and the natural gas supplied to the engine based on engine power and emission.