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

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N = Engine rpm

Q = Mass Air Flow

F = Mass Fuel Flow

Calculate 110

T= Throttle position

dT/dt = Acceleration of p Calculate i20 AF = Desired Air Fuel

C = ln-cylinder pressure Calculate 130 C = Average Cp Emissions oC = Standard deviation of Cer

Pw = Pulse width of injector Calculate 150

Calculate 16O.

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HYDROGEN ENRCHED NATURAL GAS AS hydrogen allowed the engine to be operated much leaner A MOTOR FUEL WITH WARIABLE AIR than was possible on gasoline alone. The result of this FUEL RATO AND FUEL MXTURE RATO research was that NO emissions were reduced below the CONTROL 1977 EPA standard of 0.4 gmper mile. The article states that "At an equivalence ratio of 0.53. very low NO and CO were

This is a Divisional of Application Ser. No. 08/428,626 produced and engine thermal efficiency was substantially filed Apr. 25, 1995, now U.S. Pat. No. 5,666.923. increased over stock gasoline configurations. The article This invention is a Continuation-In-Part to U.S. Appli mentions

that in order to "operate a vehicle on fuel mixtures gasoline and hydrogen, an onboard source of hydrogen is cation Ser. No. 08/237,900 entitled Hydrogen Enriched required. Onboard storage of hydrogen, either as a com Natural Gas as a Clean Motor Fuel filed on May 4, 1994. pressed gas, as a liquid at cryogenic temperature, or as a This invention relates to mobile vehicle fuels, and in particular to a hydrogen and natural gas mixture used as a hydride is not a practical solution today. Direct generation of fuel for combustion engines and a lean burn throttle control as the bestfrom hydrogen gasoline in an onboard reactor was selected solution to the problem." The main problem with algorithm to optimize a vehicle emissions and power. This this device was that the reactor described has not been invention was funded in part under contract no. DCA 15 adopted due to the complexity of the device. 92SE20061505026 from the Florida Energy Office. The articles by MacDonald, J. S...entitled "Evaluation of BACKGROUND AND PRIOR ART the Hydrogen Supplemented Fuel Concept with an Experi mental Multicylinder Engine" Automotive Engineering

Due to the world's depleting reserves of fossil fuels such Congress and Exposition. SAE Paper #76001 (1976), and as oil, there exists a need for alternative fuel vehicles by Parks. F. B., entitled "A Single-Cylinder Engine Study (AFV's). The Energy Policy Act (EPACT) signed by Presi of Hydrogen-Rich Fuels" Automotive Engineering Congress dent Bush in 1992 requires that states and the federal and Exposition. SAE Paper #760099 (1976) were by authors government take steps to reduce energy use and to shift to from General Motors that also investigated the use of other sources of energy, including the addition of alternative hydrogen-enriched gasoline. Reflecting on Houseman et fuel vehicles(AFV's) to federal and state fleets. Individual al.'s work, MacDonald states that, "while this approach states such as California and New York have instituted goals (hydrogen reactor) as been shown to be feasible, it does have of near-zero emission standards for percentages of new its limitations. A problem is the maximum theoretical yield vehicles sold within those states in the near future. Thus, the of hydrogen per pound of fuel is about 14% by weight. need exists for alternative fuels. 30 Another problem is the hydrogen generator is at best only Natural gas has long been considered an excellent alter 80% efficient, so that any gasoline going to the generator native fuel since it is considered much cleaner than other represents an efficiency loss, which is a loss in fuel economy. fossil fuels such as oil, and its reserves are much larger than For these reasons it is desirable to keep the quantity of crude oil. Natural gas which is primarily composed of hydrogen required for acceptable engine operation to a methane and combinations of Carbon Dioxide, Nitrogen, 35 minimum. This article goes on to report that when 14.4% of Ethane. Propane. Iso-Butane, N-Butane, Iso Pentane, the fuel mass was hydrogen the engine operated satisfacto N-Pentane, and Hexanes Plus, is a renewable energy source rily with an equivalence ratio of 0.52 and the NO levels had since anaerobic bacterial eventually will convert all plants dropped below the EPA mandated level of 0.4 gmper mile. into methane type gas. Natural gas has an extremely high Several U.S. patents have incorporated similar concepts. octane number, approximately 130, thus allowing higher For example. U.S. Pat. No. 4376,097 to Emelock describes compression ratios and broad flammability limits. a hydrogen generator for motor vehicles. U.S. Pat. No. A problem with using natural gas is reduced power output 4.508,064 to Watanabe describes a customized engine for when compared to gasoline, due mostly to the loss in burning hydrogen gas. U.S. Pat. No. 5.176.809 to Simuni volumetric efficiency with gaseous fuels, as well as the lack describes a technique of producing and recycling hydrogen of the infrastructure for fueling natural gas vehicles. Another 45 from exhaust gases.

problem area is the emissions produced by these natural gas Some research has been conducted for combining hydro vehicles. Although, the emissions are potentially less than gen and natural gas as a fuel mixture. Articles by Nagalin that of gasoline vehicles, these vehicles generally require gam et al. entitled: "Performance Study Using Natural Gas, some types of emissions controls such as exhaust gas Hydrogen-Supplemented Natural Gas and Hydrogen in AVL recirculation(EGR), positive crankcase ventilation(PCV), Research Engine". International Journal of Hydrogen and/or unique three-way catalyst. A still another problem Energy, Vol 8. No. 9, pp. 715-720, 1983: Fulton et al. with using natural gas vehicles is the slow flame speed entitled: "Hydrogen for Reducing Emissions from Alterna which requires that the fuel be ignited substantially before tive Fuel Vehicles" 1993 SAE Future Transportation top dead center (BTDC). In general. most internal combus Conference. SAE Paper from Alternative Fuel Vehicles" tion engines running on gasoline operate with a spark 55 1993 SAE Future Transportation Conference. SAE Paper advance of approximately 35 degrees BTDC where as the #931813, (1993) and an article by Yusuf entitled: "In Cyl same engine operating on natural gas will require an inder Flame Front Growth Rate Measurement of Methane approximate advance of 50 degrees BTDC. The slower burn and Hydrogen Enriched Methane Fuel in a Spark Ignited rate of the fuel results in reduced thermal efficiency and poor Internal Combustion Engine. Unpublished Masters Theseis, burn characteristics. University of Miami (1990) each disclosed such combina Proposed alternative fuels utilizing hydrogen and fossil tions of a fuel mixture. However, the mixtures were gener fuels have also been used with resulting problems. In an ally limited to 20% hydrogen and the rest generally methane. article entitled Houseman et al., "A Two-Charge Engine U.S. Pat. No. 5,139.002 to Lynch et al., states that Concept: Hydrogen Enrichment" SAE Paper #741169 hydrogen enriched mixtures should only contain mixtures of (1974), research was conducted at the Jet Propulsion Labo 65 up to levels of between “10 and 20%." See column 9, lines ratory. The researchers ran a V-8 internal combustion engine 49-60, and column 16, lines 14-21. At column 9, lines on a mixture of gasoline and hydrogen. The addition of 37-60, Lynch et al. states that “Relatively few tests were

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necessary to rule out the 25% and 30% mixtures(of 4,213,435 to Simko; 4,244,023 to Johnson: 4.406.261 to hydrogen) . . . " Ikeura 4.471.738 to Smojver; 4.512.304 to Snyder; and Despite its clean burning characteristics, the utilization of 4,730,590 to Sogawa.

hydrogen has had many problems as an alternative fuel. Operating an engine at lean burn was attempted by U.S. Primarily, the use of hydrogen in vehicles has been limited Pat. No. 4.499,872 to Ward et al. However, the Ward system by the size, weight, complexity and cost of hydrogen storage is restricted to an adiabatic engine design and requires options as well as the cost of hydrogen. elaborate structural components and connections such as a The controlling of air/fuel ratios and engine power has microwave generator in order to operate.

been limited in past applications. Generally, a spark ignition O

(SI) engine's power is controlled through a process called SUMMARY OF THE INVENTION throttling. Throttling controls the volume of air that enters a The first objective of the present invention is to provide a combustion engine. The throttle system is formed from one hydrogen and natural gas mixture that can extend the lean or more throttle blades which are placed in the air inlet combustion limits of natural gas as a motor fuel. stream. During a "closed throttle" position also referred to as The second object of this invention is to provide a IDLE, the throttle blade closes off the air inlet and the only 15 hydrogen and natural gas mixture that substantially reduces air entering the engine is leakage passing through the blades. the harmful exhaust emissions produced by conventional Alternatively, the only air entering the engine can be air combustion engines.

passing through a small hole in the throttle blade to provide a minimum amount of air to the engine. When the throttle is The third object of this invention is to provide a hydrogen wide open, the throttle blade is parallel to the air stream and 20 and natural gas mixture that can be used in existing gaseous vehicles without major modification and additions to those it presents a minimal air restriction to the incoming air. Most vehicles.

often the throttle blade is between full open and fully closed thus presenting a controlled restriction to the air passage. The fourth object of this invention is to provide a hydro Fuel in a sparkignition(SI) engine is generally introduced 25 gen and natural gas mixture that can meet long term federal into the inlet air stream to provide the air fuel mixture for and state emission requirements.

combustion. Various methods have been used for introduc The fifth object of this invention is to provide a hydrogen ing the fuel into the air. For example, the carbureted SI and natural gas fuel mixture that optimizes the cost of the engine is the most common method for automotive appli fuel against exhaust emissions.

cations. Here, the carburetor controls the amount of fuel The sixth object of this invention is to provide a hydrogen injected into the air stream by the fuel orifice size and the and natural gas fuel mixture that contains approximately 21 pressure drop across a venturi. To increase the amount of to 50% hydrogen and the rest natural gas such as methane. fuel to be injected given a constant pressure drop, the size of The seventh object of this invention is to provide a the jet was increased. With a fixedjet size. the amount of fuel computer controlled method of controlling the variable entering the air stream remained virtually proportional to the airlfuel ratio of a standard internal combustion engine in pressure drop across the ventur. Thus, the pressure drop 35 order to achieve lean burn.

across the ventur was a function of throttle position.

An alternative known method of introducing fuel into the controleighth

The object of this invention is to provide a throttle to achieve lean burn in a standard internal combus air stream is a fuel injector. The fuel injector can be located in a common plenum which feeds all of the cylinders on a tion engine.

multicylinder engine. At this location, the engine is said to The ninth object of the invention is to provide a control to be "throttle body injected." The injectors can alternatively maintain the air fuel ratio to optimize power, efficiency and be located in the intake runners feeding the individual for emissions as defined by the California Air Resources Board runners. This type of injection is referred to as "port injec an Ultra Low Emissions Vehicle and for a near Zero tion.” Emissions Vehicle from a closed blade throttle to a fully 45 open blade throttle position.

In both the throttle body and the port injection systems a sensor is needed to measure the amount of air entering the The tenth object of this invention is to provide a system engine in order to control the injectors and produce a to increase the fuel to air ratio (c) as a function of power constant air/fuel ratio over the full range of throttle open demand after the engine throttle is fully open. ings. Generally the output signal from a pressure sensor or 50 The eleventh object of this invention is to provide a a flow sensor is fed to a computer which uses the analog of method of determining the amount of fuel to air enrichment the airflow from the sensor to control the length of time the using a multi-criteria decision analysis algorithm optimized injector is to be open and thus control the air/fuel ratio. to minimize emissions while creating sufficient power to Additional sensors have also been included to measure meet demand.

throttle position and exhaust oxygen content. Output from 55 The twelfth object of this invention is to provide a method these sensors also can control the airlfuel ratio. a method for adjusting the hydrogen and methane fuel Power output of an engine has also been controlled mixture ratio based on engine power demands and emis strictly by the amount of fuel introduced into the combustion S1O.S.

chamber just prior to ignition. In compression ignition(CI) A preferred embodiment of the invention is to provide a engines also referred to as "Diesel Engines", the CI engine hydrogen and natural gas fuel mixture where the percent of does not usually have a throttle. Air entering the engine is hydrogen is approximately twenty-one up to fifty percent of only restricted by the intake manifold design. Fuel is the mixture. The natural gas portion of the fuel can include injected directly into the cylinder of the CI engine just prior constituents such as combinations of Methane. Carbon to ignition. The ignition is caused by the high heat generated Dioxide. Nitrogen. Ethane. Propane. Iso-Butane. N-Butane. during the compression stroke. 65 Iso Pentane, N-Pentane, and Hexanes Plus. Current internal Examples of the above prior art can be found in U.S. Pat. combustion engines that are in mass production can take this Nos.: 3,982,878 to Yamane et al.; 4.184,461 to Leung; alternative fuel without any substantial modifications to their

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systems. This alternative fuel is lean burning and emits FIG. 9 shows a graph of exhaust emissions for natural gas emissions that are below current legal standards. Specific and 20% hydrogen mixtures in parts per million(PPM) vs. mixture ratios of utilizing the mixture ratios are disclosed for Equivalence Ratio.

an internal combustion engine for a vehicle. FIG. 10 shows an enlarged sectional graph of FIG. 9 of A computer algorithm is disclosed that determines the exhaust emissions for natural gas and 20% hydrogen mix amount of fuel to air enrichment necessary to meet sufficient tures in parts per million(PPM) vs. Equivalence Ratio. power demands of an internal combustion engine's throttle FIG. 11 shows a graph of exhaust emissions for natural while minimizing emissions. The power demand is deter gas and 20% hydrogen mixtures in grams per horse power mined by a computer algorithm whose input is the throttle hour(g/HipHr) vs. Equivalence ratio.

position sensor. The position, the velocity and the accelera O FIG. 12 shows an enlarged sectional graph of FIG. 11 of tion of the throttle pedal after the throttle blades are fully exhaust emissions for natural gas and 20% hydrogen mix open will be measured and computed to determine minimum tures in grams per horse power hour(g/HipHr) vs. Equiva fuel enrichment. In addition to fuel enrichment the spark lence ratio.

timing will be varied to optimize power enhancement while minimizing emissions. The system can be operated in an 15 FIG. 13 shows a graph of exhaust emissions for natural open loop configuration utilizing lookup tables that depend gas and 28% hydrogen mixtures in parts per million(PPM) upon engine configuration. Various engine configurations vs. Equivalence Ratio.

included for the lookup tables can include but are not limited FIG. 14 shows an enlarged sectional graph of FIG. 13 of to cylinder size(4.6.8.10.12), cylinder displacement and exhaust emissions for natural gas and 28% hydrogen mix head dimensions. Alternatively the system can be operated tures in parts per million(PPM) vs. Equivalence Ratio. using exhaust gas emission monitoring on board the vehicle FIG. 15 shows a graph of exhaust emissions for natural using sensors such as NO, CO, CO, O, THC (Total gas and 30% hydrogen mixtures in grams per horse power hydrocarbon). NMOG(Nonnethane organic compounds). hour(g/HipHr) vs. Equivalence ratio.

The system can use in-cylinder pressure transducers to FIG. 16 shows an enlarged sectional graph of FIG. 15 of measure engine power output as a feedback device to close 25 exhaust emissions for natural gas and 30% hydrogen mix the control loop with the throttle position sensor and algo tures in grams per horse power hour(g/HipHr) vs. Equiva rithm or the system can be operated in the open loop lence ratio.

configuration. In addition the in-cylinder pressure transducer can be utilized to measure cylinder misfire and modify the 3. gasFIG. and 17 shows a graph of exhaust emissions for natural 36% hydrogen mixtures in parts per million(PPM) air fuel ratio in each cylinder of the engine further optimiz vs. Equivalence Ratio.

ing emission and power output. The fuel mixture of hydro gen and natural gas can be adjusted dynamically to the FIG. 18 shows an enlarged sectional graph of FIG. 17 of engine based on engine demand and emissions. exhaust emissions for natural gas and 36% hydrogen mix Further objects and advantages of this invention will be 35 tures in parts per million(PPM) vs. Equivalence Ratio. apparent from the following detailed description of a pres FIG. 19 shows a graph of exhaust emissions for natural gas ently preferred embodiment which is illustrated schemati hour(g/HpHr) and 40% hydrogen mixtures in grams per horse power cally in the accompanying drawings. vs. Equivalence ratio. FIG. 20 shows an enlarged sectional graph of FIG. 19 of

BRIEF DESCRIPTION OF THE FIGS. exhaust emissions for natural gas and 40% hydrogen mix tures in grams per horse power hour(g/HipHr) vs. Equiva

FIG. 1 shows a graph of exhaust emissions for natural gas lence ratio.

and 0% hydrogen mixtures in parts per million(PPM) vs. FIG. 21A and 21B is a Flow chart showing a preferred Equivalence Ratio.

FIG. 2 shows an enlarged sectional graph of FIG. 1 of operation of the throttle control invention. FIG.

exhaust emissions for natural gas and 0% hydrogen mixtures system control 45 22 is a schematic diagram showing a preferred in parts per million(PPM) vs. Equivalence Ratio. connections for using the throttle control invention.

FIG. 3 shows a graph of exhaust emissions for natural gas and 0% hydrogen mixtures in grams per horse power DESCRIPTION OF THE PREFERRED hour(g/HipHr) vs. Equivalence ratio. EMBODIMENT FIG. 4 shows an enlarged sectional graph of FIG. 3 of 50 exhaust emissions for natural gas and 0% hydrogen mixtures Before explaining the disclosed embodiment of the in grams per horse power hour(g/HipHr) vs. Equivalence present invention in detail it is to be understood that the ratio. invention is not limited in its application to the details of the FIG. 5 shows a graph of exhaust emissions for natural gas 55 particular of other arrangement shown since the invention is capable embodiments. Also, the terminology used herein is and 11% hydrogen mixtures in parts per million(PPM) vs. for the purpose of description and not of limitation. Equivalence Ratio.

FIG. 6 shows an enlarged sectional graph of FIG. 5 of HYDROGEN ENRICHED NATURAL GAS exhaust emissions for natural gas and 11% hydrogen mix FUELS tures in parts per million(PPM) vs. Equivalence Ratio.

FIG. 7 shows a graph of exhaust emissions for natural gas Tests were conducted with mixtures of hydrogen and and 10% hydrogen mixtures in grams per horse power natural gas. The fuels were mixed for the purpose of hour(g/HipHr) vs. Equivalence ratio. reducing emissions that are normally emitted by fossil fuels FIG. 8 shows an enlarged sectional graph of FIG. 7 of and to extend the lean combustion limit of natural gas by exhaust emissions for natural gas and 10% hydrogen mix 65 introducing hydrogen.

tures in grams per horse power hour(g/HipHr) vs. Equiva The engine used for these tests was a V-8. Chevrolet 350 lence ratio. which was rebuilt with the following specifications:

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checked for Zero drift before and after each test. In addition,

the span was checked before and after each test sequence.

Stroke: 3.480" Data was only accepted when both zero and span repeated Pistons: Cast Aluminum, Flat top with 4 valve reliefs within the limits of the instrumentation.

Cylinder heads: 76 cc The emissions pickup tube was mounted in the collector Walves: Intake 1.94" pipe 14 inches from the primary pipes. Only stainless steel Exhaust 1.50" and Teflon tubing was used for exhaust gas delivery, Compression Ratio: 9:1 intake Manifold:

Exhaust Manifold:

Aluminum Throttie Body

The following engine and atmospheric condition and

Spark Plugs: Autolite: 303 Gap: 0.035" monitoring equipment was utilized during testing and col Ignition: HEI with the vacuum spark advance removed lected by the dynamometer: Oil Pressure. Exhaust Gas Wires:

Carburetor:

Carbon Core

Throttle body with Impco Gaseous fuel meter

Temperature, Water Temperature. RPM. Torque. Barometric

Pressure. Humidity. Carburetor Air Temp. Air, and Oil 15 Temperature. The mass air flow was measured using a

The dynamometer used in the tests was a Computer 6"calibrated turbine which was attached to the carburetor Controlled Super Flow 901 with a maximum torque speci using a 6"sheet metal elbow. The exhaust gas temperature of fication of 1000 lb ft. The dynamometer was calibrated prior each cylinder was monitored using a K type thermocouple to the beginning of testing. In addition, the dynamometer mounted in an aluminum plate which was bolted between was checked for calibration drift due to the heating of the 20 the head and the exhaust header. The thermocouples were strain gage and was re-Zeroed between each pull. mounted to take the exhaust temperature reading in the For the emissions monitoring a NOVA Model Number center of the exhaust stream.

7550/B was used to measure CO, CO. O., NO. NO NO. For fuel flow, the mixture of CNG and hydrogen was fed The instrument was modified by FSEC to output the results into a Micro Motion Mass Flow Sensor, Model CMF 025. to an Analog to Digital Board mounted in an IBM 25 The Micro Motion Sensor operates using the coriolis effect. compatible 286 computer. The NOVA was calibrated using which negates the need for turbines and bearings thus certified span gases. The NOVA was zeroed using room air substantially increasing the accuracy and repeatability of the and was spanned using 35 ppm certified NO span gas, 1402 gas flow measurements. The sensor was calibrated by Micro ppm N-Hexane (Hydrocarbon), 8.993% Carbon Monoxide Motion and has a certified accuracy of 0.44% at a flow rate and 17.490% Carbon Dioxide. The hydrocarbons measured of 25 lbs per hour.

in this testing were not speciated to determine the exact Each of the test runs were conducted at 17 horsepower makeup of the total. It is generally known that approxi and 1700 rpm. The testing was conducted at this level to mately 80 to 90% of the total hydrocarbons are made up of simulate methane hydrocarbons. The methane hydrocarbons are non a light-duty truck traveling along a level paved road photo-reactive and are generally not considered to be a 35 at 55 mph.

significant pollutant. Each of the five tests included a varying mixture level The NO span gas bottle contained a liner to prevent any volumes of hydrogen with natural gas. The results of tests reaction between the gas and the bottle. The instrument was 1-5 are listed in tables 1-5 respectively.

TEST 0%. HYDROGEN and 100% Natural Gas

TEST AWF 3. EQUTV RPM HP MR TIMING TORQUE AAA-2 16.5 O 104.24 1697 17 22 50 52.7

AAA-1 16.6 0 10.361 1695 17.1 23 50 53.

AAA-3 16.8 O 1.0238 1698 16.8 22 50 52.9

AAB-2 17 O 1.O.8 698 17 22 49 52.5

AAB-3 17.2 0 1. 1698 17 22 49 52.5

AAB-1 17.3 0 0.99.42 1698 17 22 49 52.7

AAC-2 18.7 O 0.998 1700 1639 22 51 52.

AAC-3 18.8 O 0.9149 1699 17 22 51 52.5

AAC-1 19.1 O 0.9005 1700 17 22 51 52.5

AAD-1 20.9 O O.823 1697. 16.8 22 51 52

AAD-3 21.1 O 0.8152 1694 17.7 23 51 53.4

AAD-2 21.3 O 0.8075 1698 17.2 23 51 53.1

AAE-2 22.9 O 0.7511 1699 7. 22 56 529

AAE-3 23 O 0.7478 1700 7.3 23 58 53.5

AAE-1 23.2 O 0.7414 1692 16.8 22 56 523

AAF-1 23.9 O 0.7197 1669 15.5 20 56 479

AAF-2 24.3 O 0.7078 1704 16.12. 21 56 49.5

AAF-3 24.4 O 0.7049 1704 15.7 21 56 48.5

OIL, H2O PPM PPM PERCENT A + A2 NOX HC

TEST TEMP TEMP NOX HC O2 SCFM g/HipHr g/HipHr AAA-2 201 72 999 49.2 2.88 41.6 5.40 O,27

AAA-l. 202 172 999 48.8 2.88 42 541 0.26

AAA-3 203 173 999 48.9 2.93 41.6 5.46 O.7

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TEST 10%. HYDROGEN and 100% Natural Gas

AAB-2 205 172 999 47.6 3.37 42.6 5.52 0.26 AAB-3 206 17 999 46.8 3.38 42.4 5.49 0.26 AAB-1 206 173 999 46.7 9.98 42.5 5.50 0.26 AAC-2 206 172 56.2 5.2 46.1 3.54 0.34 AAC-3 205 173 603.8 58.7 5.19 46.3 3.60 0.34 AAC-1 204 73 608.9 55.2 5.17 46.2 3.62 0.33 AAD-1 204 172 82.3 69.5 6.64 50.5 1.20 0.46 AAD-3 202 17 68.2 7.2 6.39 515 1.10 0.46 AAD-2 203 172 183.5 68.4 6.64 519 1.21 O45 AAE-2 202 17 52.6 116.6 8.35 58.8 0.39 0.87 AAE-3 202 72 15.5 8.34 59.2 0.38 0.86 AAE-i 203 71 569 115.8 8.32 59 0.43 0.88 AAF-1 199 172 32.1 184.4 9.2 82.6 0.28 1.61 AAF-2 200 171 209. 9.34 63.4 0.24 1.76 AAF-3 99 171 264. 21.4 9.33 83.2 0.23 1.84

In Table 1, at an equivalence ratio of 1 on the stoichio- rise sharply. This was an indication that the engine is at or metric scale, the NO was beyond the scale of the NOVA 2 near the lean limit of combustion. Although a continuous instrument. At an equivalence ratio of 0.8333 the NO has reduction in the equivalence ratio yielded a sharp reduction fallen sharply, however, the hydrocarbons were beginning to in NO the engine misfired.

TEST 2 11% HYDROGENAND 89% Natural Gas

TEST A/F 9 EQUTV RPM HP MR TIMING TORQUE ABA-2 14.2 10.7 1.2324. 1700 17.0 22 35 52.7 ABA-1. 14.4 10.7 1.2153 1703 17 22 35 52.4 ABA-3 14.5 10.7 12069 1896 17.1 23 35 53.1 ABB-1 15.3 11.2 1.1438 1700 16.9 22 40 52.3 ABB-2 15.5 11.3 1.29 1699 16.8 22 40 52 ABB-3 15.6 115 1218 1699 17 22 40 52.4 ABC-3 17.2 118 10.174 1700 17 22 40 52.4 ABC-1 17.6 11.9 0.9943 1699 17.1 23 40 53 ABC-2 17.6 11.8 0.9943 1700 17.1 22 40 52.7 ABD-1. 19.6 11.7 0.8929 1699 17.1 23 41 53 ABD-2 19.6 116 0.8929 1697. 17.1 22 41 52.9 ABD-3 19.6 116 0.8929 1697. 17.2 23 41 53.2 ABE-2 20.6 116 0.8495 1701 17.2 23 44 53.1 ABE-1 20.7 11.6 0.8454. 1703 17.1 22 44 52.7 ABE-3 209 11.6 0.8373 1700 17.1 22 44 52.7 ABF-3 22.9 11.5 0.7642 1699 17.2 23 45 53.2 ABF-1 23 11.5 0.7.609 1701 16.9 22 45 52. ABF-2 23.4 11.5 0.7479 1699 17.1 22 45 529 ABG-2 25.9 11.5 0.6757 1701 17.1 22 55 52.7 ABG- 28 115 0.673 1706 17. 22 55 52.5 ABG-3 26.3 115 0.6654 1706 17 22 55 52.3

OL H2O PPM PPM PERCENT A1+A2 NOX HC TEST TEMP TEMP NOX HC O2 SCFM g/Hip/Hr g/HipHr ABA-2 212 172 469.2 60.8 0.51 37.8 2.31 0.30 ABA-1 211 172 454.9 6. O.S 38 2.26 0.3 ABA-3 212 172 49.7 6.3 0.52 379 2.42 0.30 ABB-1 212 174 999.5 49.4 1.28 38.1 500 0.25 ABB-2 212 174 999.5 50.8 1.27 38.2 5.04 0.25 ABB-3 213 174 999.5 48.7 13 38.3 4.99 0.24 ABC-3 209 172 854.4 41.8 3.32 41.6 4.60 0.23 ABC- 209 74 867.2 46 34 4.1.8 4.66 0.22 ABC-2 209 174 862.2 42.2 3.35 42. 4.82 0.23 ABD-1 208 173 254.6 52.1 5.48 46.6 1.52 0.31 ABD-2 20 172 259.3 52.1 547 46 153 0.31 ABD-3 207 171 259.4 519 5.48 46.5 1.53 0.31 ABE-2 205 172 57.6 614 6.5 48.5 0.97 0.38 ABE-1 207 7 168.8 615 644 48.8 10.5 0.38 ABE-3. 205 73 173.7 60.6 6.41 43. 108 0.38 ABF-3 203 7 46.1 76.1. 802 55.3 0.32 0.53 ABF-1 206 172 44.8 76.5 806 55.1 0.32 0.54 ABF-2 205 17 434 77.2 805 55.5 0.3 0.54 ABG-2 202 171 232 38.2 9.59 63. 0.19 1.1

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TEST 2, 11%. HYTDROGENAND 89% Natural Gas

ABG-1 204 171 23.4 142.6 9.65 63.9 O.19 1.5 ABG-3 202 172 24.3 140.6 9.6 63.5 O.20 1.13

This test in Table 2 began at an equivalence ratio of 1.25. As this mixture is leaned out further, the NO continues to The NO was approximately 450 ppm. The NO climbed fall significantly, and the hydrocarbons again began to rise rapidly as the air to fuel mixture was leaned out. At an 1O sharply. However, the slope is less than that noted on pure equivalence ratio of approximately 1.1 the NO had risen natural gas. beyond the instrument capability. At stoichiometric (an Test 2 was terminated at an equivalence of 0.666. equivalence ratio of 1) the NO is beginning to fall sharply Although the engine did not appear to be at the lean limit, and is reduced from that observed with no hydrogen added the hydrocarbons had risen beyond acceptable limits.

TEST 3.20% HYDROGENAND 80% Natural Gas

TEST AWF 9. EQUTV RPM HP ME TIMING TORQUE ACA-2 5. 19.7 1.1833 1700 7 22 35 52.5 ACA-1 15.1. 19.5 1.1755 1702 17 22 35 52.4 ACA-3 15.3 19.8 11601 1705 17 22 35 52.4 ACB-2 17.7 19.8 10028 1699 17.2 23 39 53.2 ACB-3 17.9 9.9 0.9916 1701 17.2 23 39 53 ACB. 8 9.8 0.986. 1698 17.3 23 39 53.4 ACC-1 19.2 19.9 0.9245 1701 17 22 43 52.5 ACC-3 19.4 20 0.9149 1700 17 22 43 52.4 ACC-2 19.5 20 0.903 1699 17 22 43 52.6 ACD-2 20.7 19.9 0.8575 1696 7.1 22 45 529 ACD-1. 21.1 20 0.8412 1700 17.1 22 45 52.7 ACD-3 2. 20 0.8412 1699 17 22 45 52.4 ACE-3 22.2 20 0.7995 17OO 17 22 51 52.5 ACE-2 22.7 20 0.7819 1699 17.1 23 5 53 ACE- 22.9 20 O.775 698 17 22 5 52.5 ACF-2 24.8 20, 0,7215 1697. 17.1 22 55 52.9 ACF-3 246 20 0.7215 1698 16.9 22 55 52.3 ACF-1 25 20 0.7. 699 17 22 55 52.7 ACG-2 26.1 20 0.68O1 1699 17.1 22 59 52.9 ACG-3 26.6 20 0.6673 1697 17 22 59 52.5 ACG-I. 27 20 0.6574 669 17 22 59 52.7 ACH-1 279 20 0.6382 17OO 16 21 60+ 49.3 ACH-2 28 20 0.6339 1709 16.5 22 60+ 50.5 ACH-3 28.1 20 0.8317 1703 16.2 21 60+ 49.9

OL, H2O PPM PPM PERCENT A1+A2 NOX HC TEST TEMP TEMP NOX HC O2 SCFM g/Hip/Hr g/HipHr ACA-2 212 172 827.5 52.7 0.81 37.5 4.05 (.26 ACA-1 219 174 824.7 54.9 0.83 37.5 404 ().27 ACA-3 212 14 827.6 53.3 0.82 37.6 406 0.28 ACB-2 210 172 999.5 411 3.81 42. 5.38 (0.22 ACB-3 20 172 999.5 41.8 3.68 42 5.36 ().22 ACB 212 172 999.5 41.1 3.63 42.3 5.37 ().22 ACC-1 210 173 775.1 47.3 4.86 44.8 447 ().27 ACC-3 209 173 773.3 466 4.89 44.3 4.41 0.27 ACC-2 20 173 802.7 46.9 4.84 44.7 4.82 ().27 ACD-2 206 173 292.5 55.6 6.19 47.3 177 0.34 ACD- 20 172 300.7 55.6 6.16 47.3 1.81 (0.34 ACD-3 206 72 288.5 55.6 6.16 47.3 175 0.34 ACE-3 206 173 1809 665 742 50.3 1.22 0.43 ACE-2 205 172 200.2 65.8 7.35 5 .30 (),43 ACE- 206 17 2007 65.8 7.34 50.9 31 O.43 ACF-2 204 70 67.9 81.1 8.63 55.1 0.47 0.57 ACF-3 203 7 66.8 81.7 8.68 55.2 0.47 ().58 ACF-1 204 172 66.1 80.9 8.63 55.5 0.47 0.57 ACG-2 202 171 34.9 96.3 949 6O.2 0.27 0.73 ACG-3 202 171 34.3 96.7 949 50.7 0.26 0.73 ACG-1 203 172 35.1 96.9 9.48 59.9 0.27 (0.74 ACH-1 200 17 20.7 132.3 10.15 63.2 0.18 L-13 ACH-2 201 17 20.6 1379 10.15 64 O.17 15 ACH-3 200 172 19.9 37.2 10.9 64.3 0.17 17

Page 31

In Test 3 at stoichiometric, the NO, is again beyond the limit of the measurement instrumentation. At an equivalence ratio of 0.95 (slightly lean) the NO, falls sharply. The NO continues to fall as the equivalence ratio is reduced to a value of 0.625, where the test was terminated. The test was 5 terminated because the engine again appeared to be missing and was apparently beyond the drivable limits.

TEST 4. 28% HYDROGEN AND 72% Natural Gas

EST A/F EQUTV RPM HP ME TIMING TORQUE ADA-3 15.3 28. 1.1791. 17O 16.8 22 36 52 ADA-2 15.4 28.2 11714 1700 169 22 36 5.2.1 ADA- 15.5 28 1.1639 1703 16.8 22 36 59 ADB-3 16.6 28. 1.0887. 1699 7 22 38 52.6 ADB-1 16. 28. 10802 1702 7 22 38 52.4 ADB-2 16.7 28.2 10802 1702 17 22 38 52.5 ADC-1 17.7 28 O92 102 12 23 39 53. ADC-3 17.7 28.1 O92 1703 11 22 39 52.6 ADC-2 18, 28.2 .0022 1699 17.3 23 39 53.4 ADD-2 19.1 28.2 0.9445 1702 16.9 22 39 52.3 ADD-1 19.6 28.3 0.920s O2 16.8 22 39 52 ADD-3 9.7 28.2 0.95 TO3 17 22 39 52.4 ADE-3 21.5 28.3 0.8391 TO1 17 22 41 52.6 ADE-1 217, 28.4 O.833 TOO 17 22 41 52.6 ADE-2 21.8 28.4 0.827.5 TO3 17.2 23 4. 53 ADF.2 23 28.5 0.7843 iO3 17.1 22 50 52.6 ADF-3 23.1 28.4 O.781 TO2 17 22 50 52.6 ADF-1 23.2 28.4 O.776 TO3 17.1 22 50 52.6 ADG-2 24.8 28.5 O.724. 1700 17 22 52 52.5 ADG-3 24.9 28.5 0.7245 1701 17.1 22 52 52.6 ADG-1 25.2 28.5 O.7159. O3 17 22 52 52.3 ADH-3 26.7 28.5 O.657 1701 17. 22 54 52.7 ADH-2 26.8 28.4 0.673. 701 17 22 54 52.6 ADH-1 27.3 28.5 0.6608 1703 17.2 23 54 53 AD-1 28.3 28.5 O.6375 701 17 22 58 52.6 AD-3. 28.4 28.5 0.6352 698 16.8 22 58 52.4 AD-2 28.7 28.5 0.6286 699 22 58 52.5

OL H2O PPM PPM PERCENT A1+A2 NOX HC TEST TEMP TEMP NOX HC O2 SCFM g/HipHr g/HipHr

ADA-2 209 172 999 52.O.89 37.8 4.95 0.26

ADB-3 209 172 999 34.2.06 39 506 0.18

ADC 209 172 999 35.2 3.58 4.7 5.33 0.19 ADC-3 209 174 999 36.8 3.38 4.7 5.36 G20 ADC-2 207 174 999 35.7 3.36 4.9 5.32 0.19 ADD-2 207 173 584.8 40.6 5 44 3.33 0.23 ADD-1 208 173 58.8 40. 5.01 44.4 3.36 0.24 ADD-3 207 17 573.3 41.7 5 44.7 330 24 ADE-3 20, 2 2S2.6 53 6.54 48.6 157 0.33 ADE-1 203 17 256.1 53.2 6.57 48.6 159 O.33 ADE-2 205 253.1 52.3 6.55 48.5 158 0.32 ADF-2 202 7. 208.4 62.6 7.53 51.2 1.36 0.41 ADF-3 203 72 220.6 61.6 7.53 514 1.45 0.40 AOF-1 202 72 211.8 61.1 752 51.6 139 0.40 ADG-2 202 17 74.1 72.4 8.59 55.1 0.52 0.51 ADG-3 200 71 75.5 74 8.58 54. O.S2 0.49 ADG- 20 17 64 1. 8.56 549 O.53 0.50 ADB-3 198 171 26.9 82.5 9.54 60 O.20 O.63 ADH-2 20 12 27.3 83. 954 60. O.21 O.63 ADH- 99 171 73 83, 9.SS 60 O. O.63 A.D.- 198 17O 15.9 104.1 10.27 63.6 O.13 O.84 AD-3 197 17 16.7 104.2 10.27 63.8 O.4 0.85 AD-2 199 1. 16.5 1044 10.27 63.8 .13 0.84

In Test 4, at stoichiometric, the NO, is again beyond the equivalence of 0.87, the NO, dropped sharply. The test was limit of the measurement instrumentation and remained 65 again terminated at an equivalence ratio of approximately beyond the limit of instrumentation at an equivalence ratio 0.625 where the NO was measured to be approximately of 0.95. When the air to fuel ratio was leaned to an 16.5 ppm. The engine was again observed to be missing

Page 32

although in cylinder pressure readings were not taken to confirm this fact. Notice that the hydrocarbons were found to be 104 ppm.

TEST 536% HYDROGENAND 64% Natural Gas

TEST AF % EQUIV RPM HP MR TIMING TOROUE

AEA-1 16 35.9 11475 1704 16.9 22 35 52

AEA-3 16 38 11475 1699 17.1 23 35 53

AEA-2 16.1 36 1.1404 1704 16.6 22 35 51.3

AEB-2 16.1 36 10144 1204 17 22 37 52.4

AEB-1 18.5 36. 0.9924 17Ol 17 22 37 52.4

AEB-1 18.5 35.9 0.987 1703 17 22 37 52.5

AEC-3 20 36 0.918 1703 17 22 38 52.4

AEC-1 20.3 35.9 0.9044 1706 16.9 22 38 52

AEC-2 20.5 35.9 0.8958 1705 17.1 22 38 52.8

AED-3 22 36 O8345 1704 17 22 43 52.5

AED-1 22.1 35.9 0.8303 1702 17 22 43 52.4

AED-3 22.2 35.9 0.827 1703 17 22 43 52.4

AEE-3 23.2 36 0.7914 1705 17 22 44 52.5

AEE-2 23.3 36 0.788 1705 17.1 22 44 52.6

AEE- 23.4 35.9 0.7846 1702 7 22 44 52.6

AEG-3 25 359 0.7344 1702 17 22 49 524

AEG-2 25.2 36 O.7286 1703 171 22 49 526

AEG-1 25.5 359 0.72 702 17 22 49 52.5

AEH-1 29.5 359 0.6224 707 7 22 50 52.

AEH-2 29.5 359 0.6224 1704 6.8 22 50 519

AEH-3 29.5 36 0.6224 1703 7.2 22 50 52.9

OIL H2O PPM PPM PERCENT A1+A2 NOX HC

TEST TEMP TEMP NOX HC O2 SCFM g/Hip/Hr g/HipHr

AEA-1 213 174 999 40.8 1.16 38 4.97 0.20

AEA-3 213 173 999 41.1 1.3 38.3 4.95 0.2O

AEA-2 211 174 999 42.8 1.15 379 5.04 0.12

AEB-2 207 74 999 32.8 3.71 49 54 O.16

AEB-1 208 174 999 321 3.7 4.1.8 5.39 0.17

AEB-3 207 173 999 33. 3.71 42.1 5.43 O.18

AEC-3 206 172 475.3 39.9 5.41 45.4 2.77 O.23

AEC-1 206 73 493.3 39.5 5.39 45.5 2.90 O.23

AEC-2 205 172 491.5 38.5 5.38 45.5 2.85 0.22

AED-3 203 173 385.1 50.8 6.7 48.9 2.41 0.32

AED-1 203 172 387.9 50.1 6.69 48.7 2.42 O.31

AED-3 204 172 395.5 50.1 6.68 48.8 2.47 O.31

AEE-3 201 171 204.1 58.4 7.53 51.1 1.33 O.38

AEE-2 203 172 206.7. 58.2 7.54 5.2 1.34 O38

AEE-1 203 73 202.6 58.4 7.58 5 1.32 O.38

AEG-3 200 72 78.8 68 8.82 54.9 0.55 0.48

AEG-2 200 170 777 67.4 8.62 54.8 0.54 0.47

AEG-1 202 172 76.9 68.4 8.85 54.9 0.54 0.48

AEH-1 199 170 12.4 105.5 0.63 64.8 0.O O.87

AEH-2 198 172 117 104.1. 10.64 65 0.1O 0.87

AEH-3 199 172 119 102.7 10.6 64.9 0.10 O.83

In Test 5at stoichiometric, the NO levels were beyond increases in the Hydro Carbons, HCs. HCs were not con the measurement limit of the instrumentation. The NO sidered to be a significant problem since HCs can be reduced levels dropped sharply at an equivalence ratio of 0.91. The using catalysts.

FIGS. 1 through 20 show partial maps of the NO, and

NO levels continue to fall to the termination of the test at hydrocarbon approximately 0.625 equivalence ratio. The NO has a low emissions at various levels of hydrogen in Natural Gas value of approximately 12 ppm. The hydrocarbons have a 55 Both 28% hydrogen and at various equivalence ratios. maximum value of 105 ppm. This is approximately the same very low NO levels a toand 36% hydrogen mixtures yielded 0.625 equivalence ratio. See FIGS.

as the hydrocarbons measured during the 30% hydrogen 13-20. The extremely low testing. The test was terminated before there was a sharp rise gm/hphr) and 12 ppm( (0.10NO levels of 28 ppm (0.21 gm/hphr) respectively were in the hydrocarbons thus indicating that the roughness was unexpected. Recall that all of the emissions readings were not being caused by running the engine beyond the lean taken at the exhaust manifold outlet. There were no emission limit. control equipment on the tested engine and there was no SUMMARY OF TESTS 1-5 catalytic converter. The levels of NO at 28% and 36% hydrogen mixtures were substantially below the strictest air

The purpose of TESTS 1 through 5 was to determine if the quality standards. For example, current air quality standards lean limit of Natural Gas can he extended by introducing in Japan require NO emissions to be below 200 ppm. This Hydrogen, H. The hypothesis used was that the leaner the 65 standard is extremely difficult to meet and has never been engine could be run without going into lean misfire, the met without substantial emissions control equipment on the lower the NO would be while only incurring moderate engine, based on the prior art known to the inventors.

Page 33

Referring back to FIGS. 2 and 4 for 0%. Hydrogen. turbocharging engine settings (ignition. Sparkplugs), Although at an equivalence ratio of 0.75 the NO level fell camshafts, intake manifold and cylinder head modifications. significantly the hydrocarbons increased at approximately compression ratios, and injection system and combinations the same rate thus indicating an unstable operating condi thereof.

tion. This same result can be noted in FIGS. 6 and 8 (11% While the invention has been described as being used for Hydrogen) and in FIGS. 10 and 12 (20% Hydrogen). mobile vehicles such as an eight (8) cylinder automobiles, However, the lean limit extends from approximately 0.75 the invention would have applicability to various other size equivalence ratio at 0% hydrogen to 0.67 equivalence ratio engines such as four(4), six (6), and twelve(12) cylinder at 20% hydrogen. It is not feasible to operate the engine at mobile engines.

these lean limits since a very small change in the air fuel Furthermore, the disclosed invention can be used with ratio will make a very significant increase in the NO levels other size engines such as but not limited to lawnmower or a very significant increase in the hydrocarbon levels. engines, trucks, vans, aircraft and trains. When the hydrogen concentration was extended to 28% there is no longer a point where the hydrocarbons abruptly VARIABLE AR/FUEL RATIO THROTTLE increase as was seen at all lower levels of hydrogen thus 15 CONTROL making lean burn a viable option. This same result was noted This portion of the invention covers a variable air/fuel at concentrations of 36% hydrogen as seen in FIGS. 17 and ratio control that optimizes emissions and power output for

lean burn applications. FIG. 21A and 21B is a Flow chart

The test results demonstrate that extremely low levels of showing a preferred operation of the throttle control inven NO are possible with acceptably moderate increases in tion. FIG. 22 is a schematic diagram showing a preferred unburned hydrocarbons using 28 % and 36% hydrogen system control connections for using the throttle control supplementation. Previous research conducted at 20% invention. Before discussing these Figures, a background for hydrogen did not indicate a significant enough reduction to this invention will now be discussed. consider the mixture of hydrogen and natural gas as a viable solution to the problem of producing extremely low NO 25 canTest results have indicated that Spark Ignition(SI) engines operate at an equivalence ratio of approximately 0.5 levels of 20% and below. The significant reduction in NO with approximately 35% by volume hydrogen in methane. was realized when the hydrogen level was raised to approxi The emissions during this test were NO of approximately mately 30% and the engine was run nearer the lean limit. In 8 ppm and HC or approximately 845 ppm. This test was addition, the lean limit of combustion was significantly conducted on the engine previously discussed. Maximum extended by the increased levels of hydrogen. The NO engine horsepower was 93 at an equivalence ratio of levels reported are an order of magnitude below the strictest approximately 0.625 while current requirements. This level of NO was achieved an equivalence ratio of 0.5.maximum Thus, the horsepower was 24 at optimum equivalence without a catalytic converter or other emissions reducing ratio is a function of desired emissions, and horsepower. hardware on the engine.

35 Varying the equivalence ratio dynamically will provide a

The tests and related data demonstrate that levels up to vehicle with needed horsepower while minimizing the emis approximately 50%. Hydrogen can be used with combustion sions from the vehicle. The optimum equivalence ratio is engines. Over 50%. Hydrogen gas in the mixture could create thus a function of the percentage of hydrogen enrichment, possible problems related to storage and safety. However, selected NO (Noxious Oxide) and HC (Hydro Carbon) the specific mixture amounts of between approximately 21 levels. engine design configuration(cylinder size. cylinder and 50% Hydrogen, can be further narrowed down by displacement, head dimensions, and the like) as well as engine size(46.8 cylinders) and regulatory concerns. desired power output

While natural gas has been referred to as including A system optimized for these parameters(hydrogen primarily methane, natural gas can include other compo enrichment. NO, HC, engine design) will produce less nents is much smaller amounts. Besides primarily contain 45 power than could be produced if the engine were operated ing methane, natural gas can include Carbon Dioxide. approximately at stoichiometric. With this system, the emis Nitrogen. Ethane. Propane. Iso-Butane. N-Butane. Iso sion levels of NO, and controlled HC's will be on the order Pentane, N-Pentane, and Hexanes Plus. of approximately 25 ppm or less. In addition the CO output While the tested engine did not use a catalytic converter, will be on the order of approximately 1% of less. These one could be added. The hydrocarbon levels at 28% and 36% 50 levels of emission would qualify the vehicle for ULVE(Ultra hydrogen at an equivalence ratio of 0.625 were both Low Vehicle Emission) status as established by the Califor approximately 104 ppm(0.84 gm/hp hr). Since approxi nia Air Resources Board(CARB). The system for introduc mately 15% of the hydrocarbons are photo reactive the total ing fuel and air into the engine can utilize either a carbure reactive hydrocarbons are approximately 16 ppm (0.13 tion system or a fuel injection system as described gm/hphr.). This level of hydrocarbon emissions is extremely 55 previously in the background section of the invention. low and there is the potential of reducing the total hydro However, the prior art systems are still limited because carbons to near zero through the use of a catalytic converter. additional power would be required for severe grade Mixtures of hydrogen and natural gas can be mixed by climbing, expressway merging and passing. In the prior art known methods such as but not limited to sonic mixing, or systems a wide open throttle could still cause the engine to merely injecting hydrogen into natural gas, or injecting not produce sufficient power for these extreme conditions. In natural gas into hydrogen. the subject invention. the airffuel ratio can be shifted during While the alternative fuel mixture in this invention has the wide open throttle toward stoichiometric. Thus, in the been successfully used with existing combustion engines, instant invention, the air/fuel ratio is shifted toward stoichio modifications on existing engines can be accomplished in metric as a function of the instantaneous power demand. order to enhance engine performance such as horsepower. 65 The novel throttle control can use a "carburetor" or "fuel For example, the alternative fuel disclosed herein can be injection” system. For a carbureted system, a secondary used in combustion engines include but are not limited to demand regulator system can be operated in parallel with the

Page 34

standard demand regulator system. The standard demand there is a separate in-cylinder transducer 9. Control unit 14 regulator System can be adjusted to maintain an optimal can also control the fuel passing into injector 4 by fuel air/fuel ratio. When the throttle blades in the primary system supply 16. The fuel supply 16 can store a high pressure are wide open the secondary system is activated. The mixture of natural gas(CH) and hydrogen(H) in a mixture secondary system supplies additional fuel to the system as a as that described in relation to the discussion of FIGS. 1-20 function of the system demand and the throttle pedal posi previously. Alternatively, fuel supply 16 can store separate tion. containers of natural gas(i.e. CH) and hydrogen (H). For FIG. 21A and 21B is a Flow chart showing a preferred example, CH can be stored in one high pressure cylinder. operation of the throttle control invention. In the injection For separate storage, hydrogen. H. can be stored either in system, the standard electronic control unit(ECU) such as O a high pressure cylinder, in a hydride, or in a cryogenic form. the control unit 10 of U.S. Pat. No. 4,730,590 to Sagawa, Furthermore, the separately stored hydrogen could be gen which is incorporated by reference. can be programed to erated on board the vehicle through a reforming process of implement the algorithm. Referring to FIG. 21. From Start, CH. When stored separately, the ratio of CH and H can step 110 is to calculate engine speed(rpm) N. mass air flow be varied dynamically and controlled by control unit 14 as Q, and mass fuel flow F. Step 120 is to calculate throttle 15 a function of output emissions and engine power. position T velocity of throttle position dT/dt, and accel The algorithm in our invention will maintain the air/fuel eration of throttle position dT/dt. Step 130 is calculate ratio at the optimum for emission while the engine power is current emissions. Step 140 is calculate desired air fuel ratio under the control of the throttle. Experimentation indicates AF, which is a function of acceptable emission levels. that many internal combustion engines will operate best at desired vehicle speed and acceleration values computed 20 approximately ()=approximately 0.625. This however needs above. Step 150 is to calculate actual air fuel AF, which is to be individually determined for each different engine calculated from Q and F. Step 160 is to calculate in-cylinder configuration.

pressure C average in-cylinder pressure C. standard The entire system is under the control of the driver. The deviation of in-cylinder pressure oc and Z value equal to transition from the fixed airffuel ratio to the variable air/fuel 25 ratio can be automatic where the driver is unaware of the

C - Carl change. Alternatively, the system can require additional -. force on the throttle pedal to alert the driver that the vehicle is now being operated in less than the optimal range.

Step 200 of FIG. 21A goes to the top of FIG.21B. Step 210 Although the control algorithm embodiment and sche is to calculate 6 which is equal to the desired air fuel. AF matic has been described for use with a hydrogen gaseous minus actual air fuel. AF Step 220 holds if 8=0 and Z-10 fuel, the invention would have applicability to other types of at box. 222 there is is no change go to step 100. If 6-0 and mobile vehicle fuels that can support an extreme lean burn Z>1.0 there is more cylinder pressure variation than is condition.

normally expected. Go to step 224 to increase Pw, the pulse While the invention has been described, disclosed, illus width of the injector which will increase fuel, and set an 35 trated and shown in various terms of certain embodiments or engine alarm, 226 which can be a warning dashboard light modifications which it has presumed in practice, the scope that the engine is malfunctioning and that the driver should of the invention is not intended to be, nor should it be check the engine. If 8<0, go to step 232 and increase Pw deemed to be, limited thereby and such other modifications which will increase fuel to the engine and then go to step or embodiments as may be suggested by the teachings herein 100. If 8 is not <0 go to step 240 and check Z. If Z <1 go are particularly reserved especially as they fall within the to step 242 and reduce the amount of fuel to the engine. breadth and scope of the claims here appended. lower Pw, and then go to step 100. IfZ is not <1 go to step We claim:

250 reduce Pw and set engine alarm 260 that engine is 1. A control system for varying air and fuel ratios of an malfunctioning and then go to step 100. internal combustion engines running at lean burn with FIG. 22 is a schematic diagram showing a preferred 45 reduced emissions during cycles for instantaneous power System of the control connections for using the throttle demands comprising:

control algorithm of FIGS. 21A and 21B with the internal an internal combustion engine of a mobile vehicle oper combustion engine 10 in a mobile vehicle. Air is inducted ating on a fuel Supply having a mixture of hydrogen and through the intake manifold 1 and the volume can be natural gas;

measured by sensor 2 whose output is sent to control unit 14 5 an air fuel control for maintaining fuel supplied to the a computer that runs the algorithm flow chart depicted engine to remain at a selected air fuel ratio to achieve previously in FIGS. 21A and 21B. The position of the a lean burn condition;

throttle blade can be determined by sensor 3. Sensor 3 can a throttle for controlling the amount of fuel being supplied be configured such that when the throttle blade is fully to the engine, the throttle having a closed position open(parallel to intake air) the additional travel of the 55 through a fully open position;

throttle can occur to indicate an operator(drivers) desire for increased power. Component 4 can be the fuel injector a sensor activated by the fully open position of the whose Pw pulse width is controlled by control unit 14. As throttle, wherein the activated sensor causes the air fuel the pulse width to injector 4 is increased, the air fuel ratio (c) control to increase the percentage of fuel in the selected can be increased. Component 5 is the mass fuel flow sensor air fuel ratio; and which also provides input for control unit 14. Component 6 means for dynamically adjusting mixture ratios of the is the emission sensor which can monitor NO, CO, CO. hydrogen gas and the natural gas supplied to the engine THC. NMOG and Opassing into muffler 12. Sensor 7 is the based on engine power and emission. engine 10 temperature sensor. Sensor 8 is the crank angle 2. The control system of claim 1, wherein the fuel supply sensor used to determine engine 10 speed and which of the 65 includes:

cylinder(s) is being fired. Sensor 9 is the in-cylinder pressure a mixture of approximately 21 to 50% hydrogen gas and transducer for engine 10. For each cylinder of the engine, the remainder being natural gas.

Page 35

3. The control system of claim 1, wherein the fuel supply being natural gas to an internal combustion engine of a includes: mobile vehicle:

a mixture of approximately 28 to 36% hydrogen gas and operating the air fuel ratio of the vehicle to achieve a lean the remainder being natural gas. burn condition without misfiring the engine; and 4. The control system of claim 1, wherein the air-fuel means for dynamically adjusting mixture ratios of the control includes: hydrogen gas and the natural gas supplied to the engine a carburetor. based on engine power and emission. 5. The control system of claim 1, wherein the air-fuel 9. A method for producing lean burn and low emission control includes:

O rates for an internal combustion engine of a mobile vehicle a fuel injection control. using a dynamically adjustable alternative fuel as compared 6. The control system of claim 1, where the selected air to the burn and emission rates of gasoline fuel to achieve a fuel ratio is controlled by: lean burn condition, comprising the steps of: engine speed, spark timing, air flow and throttle pedal feeding an alternative gaseous fuel mixture of approxi position. 15 mately 28 to approximately 36% hydrogen gas and the 7. The control system of claim 6, wherein the selected air remainder being natural gas to an internal combustion fuel ratio is further controlled by at least one of: engine of a mobile vehicle: in-cylinder pressure, exhaust emissions and fuel flow. operating the vehicle engine at an air and fuel equivalence 8. A method for producing lean burn and low emission ratio of approximately 0.625 to achieve a lean burn rates for an internal combustion engine of a mobile vehicle condition without misfiring the engine and using a dynamically adjustable alternative fuel as compared means for dynamically adjusting mixture ratios of the to the burn and emission rates of gasoline fuel to achieve a hydrogen gas and the natural gas supplied to the engine lean burn, comprising the steps of: based on engine power and emission. feeding an alternative gaseous fuel mixture of above 21 to approximately 50% hydrogen gas and the remainder : :: k : ck