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

Page 1 — bibliographic record

Page 2

4,569,890 2/1986 Barthel ...... 48/197 FM 1936,155 11/1933 De Florez .......................... 48/199 FM 4,617,892 10/1986 Staerzl ...... ... 123/352 1936,156 11/1933 De Florez. ... 48/199 FM 4,722,303 2/1988 Leonhard .. ... 123/3 2.956,093 10/1960 Nicolai ... ... 48/199 FM 4,730,590 3/1988 Sogawa ... ... 123/489 3,759,679 9/1973 Franz et al... 48/199 FM 5,123,397 6/1992 Richeson ... ... 123/568 3,976,034 8/1976 Shinohara et al.......................... 123/3 5,139,002 8/1992 Lynch et al. .. ... 123/575 3,982,878 9/1976 Yamane et al. ..... ... 431/2 5,156,114 10/1992 Gunnerman ... ... 123/1 A 3,982,910 9/1976 Houseman et al. ........ ... 48/61 5,176,809 1/1993 Simuni .......... 204/273 4,086,877 5/1978 Henkel et al. ................. ... 123/3 5,207,185 5/1993 Greiner et al. ... 123/3 4,112,876 9/1978 Mentschel ... ... 123/3 5,248,566 9/1993 Kumar et al. ..... ... 429/19 4,131,086 12/1978 Noguchi et al. ... 123/3 5,251,601 10/1993 Leshner et al. ... 123/436 4,143,620 3/1979 Noguchi et al. ............................ 123/3 5,284,113 2/1994 Svensson .. ... 123/344 4,184,461 1/1980 Leung '......... . 123/32 EH 5,293.857 3/1994 Meyer ....... ... 123/57 4,213,435 7/1980 Simko . ... 123/446 5,297,515 3/1994 Gale et al. .................................. 123/3 4,223,642 9/1980 Okubo ......................................... 123/3 5,299,536 4/1994 Moard et al. . 123/DIG. 12 4,244,023 1/1981 Johnson .. ... 364/431 5,516,967 5/1996 Pandey et al. ...........is ... 48/198.1 4,376,097 3/1983 Emelock ................................. 422/189 4,376.427 3/1983 Mizuno .................................. 123/339 OTHER PUBLICATIONS

4,471,738 3. S."m IE Harrow et al., Mixture Strength Control of Engine Power: 4,499,872 2/1985 Ward et al. . . .23/344 Fuel Economy and Specific Emissions From Gasoline 4,508,064 4/1985 Watanabe ... ... 123/1 A Engines Running one Fully Vaporized Fuel/Air Mixtures, 4512,304 4/1985 Snyder ........ ... 23/344 Conference publication Fuel Economy & Emissions of Lean 4520,763 6/1985 Lynch et al. ............................ 123/1 A Burn Engines, Jun. 1979, pp. 39-50.

Page 3

Drawing sheet — no readable text.

Page 4

Drawing sheet — no readable text.

Page 5

Drawing sheet — no readable text.

Page 6

Drawing sheet — no readable text.

Page 7

Drawing sheet — no readable text.

Page 8

Drawing sheet — no readable text.

Page 9

Drawing sheet — no readable text.

Page 10

Drawing sheet — no readable text.

Page 11

Drawing sheet — no readable text.

Page 12

Drawing sheet — no readable text.

Page 13

Drawing sheet — no readable text.

Page 14

Drawing sheet — no readable text.

Page 15

Drawing sheet — no readable text.

Page 16

Drawing sheet — no readable text.

Page 17

Drawing sheet — no readable text.

Page 18

Drawing sheet — no readable text.

Page 19

Drawing sheet — no readable text.

Page 20

Drawing sheet — no readable text.

Page 21

Drawing sheet — no readable text.

Page 22

Drawing sheet — no readable text.

Page 23

N = Engine rpm

Q = Mass Air Flow

F= Mass Fuel Flow

Calculate 110

T= Throttle position

dT/dt = Acceleration of Tp Calculate 120 AF = Desired Air Fuel To dT/dt dT/dt AF = Actual Air Fuel C = ln-cylinder pressure Calculate 130 Cor = Average Cor Emissions oC = Standard deviation of Cp Cor C

Pw = Pulse width of injector Calculate 150

Calculate 160

Page 24

Drawing sheet — no readable text.

Page 25

Drawing sheet — no readable text.

Page 26

HYDROGENENRICHED NATURAL GASAS hydrogen allowed the engine to be operated much leaner A MOTORFUEL WITH WARIABLE AIR than was possible on gasoline alone. The result of this FUELRATO AND FUELMIXTURE 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 invention relates to mobile vehicle fuels, and in produced and engine thermal efficiency was substantially particular to a hydrogen and natural gas mixture used as a increased over stock gasoline configurations. The article fuel for combustion engines and a lean burn throttle control mentions that in order to "operate a vehicle on fuel mixtures algorithm to optimize a vehicle emissions and power. This of gasoline and hydrogen, an onboard source of hydrogen is required. Onboard storage of hydrogen, either as a com invention is a continuation in part to U.S. application Ser. 10 pressed

No. 08/237,900 entitled Hydrogen Enriched Natural Gas as hydride isgas, not as a liquid at cryogenic temperature, or as a a practical solution today. Direct generation of a Clean Motor Fuel fried on May 4, 1994 abandoned and refiled on Mar. 4, 1996 as continuation application Ser. No. hydrogen from gasoline in an onboard reactor was selected 08/611,400, and now allowed. This invention was funded in as thedevicebest solution to the problem.” The main problem with part under contract no. DCA 92SE20061505026 from the 15 this adopted due was that the reactor described has not been to the complexity of the device.

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 20 Congress and Exposition, SAE Paper #760101 (1976), and as oil, there exists a need for alternative fuel vehicles by Parks, F. B., entitled "A Single-Cylinder Engine Study of (AFV's). The Energy Policy Act (EPACT) signed by Presi Hydrogen-Rich Fuels" Automotive Engineering Congress dent Bush in 1992 requires that states and the federal and Exposition, SAEPaper #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 25 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 Pentune, 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 corabining 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), 50 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

Page 27

necessary to rule out the 25% and 30% mixtures (of No. 4,184,461 to Leung; U.S. Pat. No. 4,213,435 to Simko; hydrogen). . .” U.S. Pat. No. 4,244,023 to Johnson; U.S. Pat. No. 4406.261 Despite its clean burning characteristics, the utilization of to Ikeura U.S. Pat. No. 4471.738 to Smojver; U.S. Pat. No. hydrogen has had many problems as an alternative fuel. 4,512.304 to Snyder; and U.S. Pat. No. 4,730,590 to Primarily, the use of hydrogen in vehicles has been limited Sogawa.

by the size, weight, complexity and cost of hydrogen storage Operating an engine at lean burn was attempted by U.S. options as well as the cost of hydrogen. Pat. No. 4499,872 to Ward et al. However, the Ward system The controlling of airlfuel ratios and engine power has is restricted to an adiabatic engine design and requires been limited in past applications. Generally, a spark ignition elaborate structural components and connections such as a (SI) engine's power is controlled through a process called 10 microwave generator in order to operate. throttling. Throttling controls the volume of air that enters a combustion engine. The throttle system is formed from one SUMMARY OF THE INVENTION or more throttle blades which are placed in the air inlet The first objective of the present invention is to provide a stream. During a "closed throttle” position also referred to as 15 hydrogen and natural gas mixture that can extend the lean IDLE, the throttle blade closes off the air inlet and the only combustion limits of natural gas as a motor fuel. air entering the engine is leakage passing through the blades.

Alternatively, the only air entering the engine can be air The second object of this invention is to provide a hydrogen passing through a small hole in the throttle blade to provide the harmful and natural gas mixture that substantially reduces a minimum amount of air to the engine. When the throttle is 20 combustion engines.exhaust emissions produced by conventional wide open, the throttle blade is parallel to the air stream and it presents a minimal air restriction to the incoming air. Most The third object of this invention is to provide a hydrogen often the throttle blade is between full open and fully closed and natural gas mixture that can be used in existing gaseous thus presenting a controlled restriction to the air passage. vehicles without major modification and additions to those Fuel in a sparkignition (SI) engine is generally introduced vehicles.

into the inlet air stream to provide the air fuel mixture for 25 The fourth object of this invention is to provide a hydro combustion. Various methods have been used for introduc gen and natural gas mixture that can meet long term federal ing the fuel into the air. For example, the carbureted SI and state emission requirements.

engine is the most common method for automotive appli The fifth object of this invention is to provide a hydrogen cations. Here, the carburetor controls the amount of fuel 30 and natural gas fuel mixture that optimizes the cost of the injected into the air stream by the fuel orifice size and the fuel against exhaust emissions, pressure drop across a venturi. To increase the amount of The sixth object of this invention is to provide a hydrogen fuel to be injected given a constant pressure drop, the size of and natural gas fuel mixture that contains approximately 21 the jet was increased. With a fixedjetsize, the amount of fuel to 50% hydrogen and the rest natural gas such as methane. entering the air stream remained virtually proportional to the The seventh object of this invention is to provide a pressure drop across the ventur. Thus, the pressure drop 35 computer controlled method of controlling the variable across the ventur was a function of throttle position. air/fuel ratio of a standard internal combustion engine in An alternative known method of introducing fuel into the order to achieve lean burn.

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

be “throttle body injected.” The injectors can alternatively be located in the intake runners feeding the individual The ninth object of the invention is to provide a control to runners. This type of injection is referred to as "port injec maintain the air fuel ratio to optimize power, efficiency and tion.' 5 emissions as defined by the California Air Resources Board

In both the throttle body and the port injection systems a for an Ultra LOW Emissions Vehicle and for a near Zero sensor is needed to measure the amount of air entering the open bladeVehicle

Emissions from a closed blade throttle to a fully throttle position.

engine in order to control the injectors and produce a constant air/fuel ratio over the full range of throttle open The tenth object of this invention is to provide a system ings. Generally the output signal from a pressure sensor or 50 to increase the fuel to air ratio (d) as a function of power a flow sensor is fed to a computer which uses the analog of demand after the engine throttle is fully open. the airflow from the sensor to control the length of time the The eleventh object of this invention is to provide a injector is to be open and thus control the airlfuel ratio. method of determining the amount of fuel to air enrichment Additional sensors have also been included to measure using a multi-criteria decision analysis algorithm optimized throttle position and exhaust oxygen content. Output from 55 to minimize emissions while creating sufficient power to these sensors also can control the air/fuel ratio. meet demand.

Power output of an engine has also been controlled The twelfth object of this invention is to provide a method strictly by the amount of fuel introduced into the combustion a method for adjusting the hydrogen and methane fuel chamber just prior to ignition. In compression ignition (CD mixture ratio based on engine power demands and emis engines also referred to as "Diesel Engines”, the CI engine sions.

does not usually have a throttle. Air entering the engine is A preferred embodiment of the invention is to provide a only restricted by the intake manifold design. Fuel is hydrogen and natural gas fuel mixture where the percent of injected directly into the cylinder of the CI engine just prior hydrogen is approximately twenty-one up to fifty percent of to ignition. The ignition is caused by the high heat generated the mixture. The natural gas portion of the fuel can include during the compression stroke. 65 constituents such as combinations of Methane, Carbon Examples of the above prior art can be found in U.S. Dioxide, Nitrogen, Ethane, Propane, Iso-Butane, N-Butane, Patents: U.S. Pat. No. 3,982,878 to Yamane et al.; U.S. Pat. Iso Pentane, N-Pentane, and Hexanes Plus. Current internal

Page 28

combustion engines that are in mass production can take this FIG. 9 shows a graph of exhaust emissions for natural gas alternative fuel without any substantial modifications to their and 20% hydrogen mixtures in parts per million (PPM) vs. systems. This alternative fuel is lean burning and emits Equivalence Ratio.

emissions that are below current legal standards. Specific FIG. 10 shows an enlarged sectional graph of FIG. 9 of mixture ratios of utilizing the mixture ratios are disclosed for exhaust emissions for natural gas and 20% hydrogen mix an internal combustion engine for a vehicle. tures in parts per million (PPM) vs. Equivalence Ratio. A computer algorithm is disclosed that determines the amount of fuel to air enrichment necessary to meet sufficient FIG. 11 shows a graph of exhaust emissions for natural power demands of an internal combustion engine's throttle gas and 20% hydrogen mixtures in grams per horse power while minimizing emissions. The power demand is deter hour (g/HipHr) vs. Equivalence ratio. mined by a computer algorithm whose input is the throttle FIG. 12 shows an enlarged sectional graph of FIG. 11 of position sensor. The position, the velocity and the accelera exhaust emissions for natural gas and 20% hydrogen mix tion of the throttle pedal after the throttle blades are fully tures in grams per horse power hour (g/HpHr) vs. Equiva open will be measured and computed to determine minimum lence ratio.

fuel enrichment. In addition to fuel enrichment the spark 15 FIG. 13 shows a graph of exhaust emissions for natural liming will be varied to optimize power enhancement while gas and 28% hydrogen mixtures in parts per million (PPM) minimizing emissions. The system can be operated in an vs. Equivalence Ratio.

open loop configuration utilizing lookup tables that depend upon engine configuration. Various engine configurations FIG. 14 shows an enlarged sectional graph of FIG. 13 of exhaust emissions for natural gas and 28% hydrogen mix included for the lookup tables can include but are not limited 20 tures to cylinder size (4.6.8,10,12), cylinder displacement and in parts per million (PPM) vs. Equivalence Ratio. head dimensions. Alternatively the system can be operated FIG. 15 shows a graph of exhaust emissions for natural using exhaust gas emission monitoring on board the vehicle gas and 30% hydrogen mixtures in grams per horse power using sensors such as NO, CO, CO, O, THC (Total hour (g/HipHr) vs. Equivalence ratio.

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

rithm or the system can be operated in the open loop FIG. 17 shows a graph of exhaust emissions for natural configuration. In addition the in-cylinder pressure transducer 30 gas and 36% hydrogen mixtures in parts per million (PPM) can be utilized to measure cylinder misfire and modify the vs. Equivalence Ratio.

air fuel ratio in each cylinder of the engine furfier optimiz FIG. 18 shows an enlarged sectional graph of FIG. 17 of ing emission and power output. The fuel mixture of hydro exhaust emissions for natural gas and 36% hydrogen mix gen and natural gas can be adjusted dynamically to the tures in parts per million (PPM) vs. Equivalence Ratio. engine based on engine demand and emissions. 35 FIG. 19 shows

Further objects and advantages of this invention will be gas and 40% hydrogen a graph of exhaust emissions for natural apparent from the following detailed description of a pres hour mixtures in grams per horse power ently preferred embodiment which is illustrated schemati (g/HipHr) vs. Equivalence ratio. cally in the accompanying drawings. FIG. 20 shows an enlarged sectional graph of FIG. 19 of

BRIEF DESCRIPTION OF THE FIGURES

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. operation of the throttle control invention. FIG. 2 shows an enlarged sectional graph of FIG. 1 of FIG. 22 is a schematic diagram showing a preferred exhaust emissions for natural gas and 0% hydrogen mixtures 45 system control connections for using the throttle control in parts per million (PPM) vs. Equivalence Ratio. invention.

FIG.3 shows a graph of exhaust emissions for natural gas and 0% hydrogen mixtures in grams per horse power hour DESCRIPTION OF THE PREFERRED (g/HipHr) vs. Equivalence ratio. 50

EMBODIMENT

FIG. 4 shows an enlarged sectional graph of FIG. 3 of 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 particular arrangement shown since the invention is capable 55 of other 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 hour natural gas. The fuels were mixed for the purpose of (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:

Page 29

The following engine and atmospheric condition and monitoring equipment was utilized during testing and col

Bore: 4.030" (0.030 over bore from standard) lected by the dynamometer: Oil Pressure, Exhaust Gas

Pistons: Cast Aluminum, Flat top with 4 valve reliefs Temperature, Water Temperature, RPM, Torque, Barometric Cam: Stock Pressure, Humidity, Carburetor Air Temp, Air, and Oil Cylinder heads: 6cc Temperature. The mass air flow was measured using a 6"

Exhaust 1.50" calibrated turbine which was attached to the carburetor using

Compression Ratio: 9:1 a 6" sheet metal elbow. The exhaust gas temperature of each

Intake Manifold: Aluminum Throttle Body cylinder was monitored using a K type thermocouple

Exhaust Manifold: 1%" Steel pipe headers 10 amounted in an aluminum plate which was bolted between Spark Plugs: Autolite: 303 Gap: 0.035" the head and the exhaust header. The thermocouples were Ignition: HEI with the vacuum spark advance removed amounted to take the exhaust temperature reading in the Wires: Carbon Core center of the exhaust stream. Carburetor: Throttle body with Impco Gaseous fuel meter For fuel flow, the mixture of CNG and hydrogen was fed

into a Micro Motion Mass Flow Sensor, Model CMF 025.

The dynamometer used in the tests was a Computer The MicroMotion Sensor operates using the coriolis effect, Controlled Super Flow 901 with a maximum torque speci which negates the need for turbines and bearings thus fication of 1000lbft. The dynamometer was calibrated prior substantially increasing the accuracy and repeatability of the to the beginning of testing. In addition, the dynamometer gasflow measurements. The sensor was calibrated by Micro Motion and has a certified accuracy of 0.44% at a flow rate was checked for calibration drift due to the heating of the 20 of 25 lbs per hour.

strain gage and was re-zeroed between each pull. Each of the test runs were conducted at 17 horsepower For the emissions monitoring a NOVA Model Number and 1700 rpm. The testing was conducted at this level to 7550/B was used to measure CO, CO. O., NO, NO, NO. simulate a light-duty truck traveling along a level paved mad The instrument was modified by FSEC to output the results at 55 mph. Each of the five tests included a varying mixture to an Analog to Digital Board amounted in an IBM 25 level volumes of hydrogen with natural gas. The results of compatible 286 computer. The NOVA was calibrated using tests 1-5 are listed in tables 1-5 respectively. certified span gases. The NOVA was zeroed using room air In Table 1, at an equivalence ratio of 1 on the stoichi and was spanned using 35 ppm certified NO span gas, 1402 metric scale, the NO was beyond the scale of the NOVA ppm N-Hexane (Hydrocarbon), 8.993% Carbon Monoxide instrument. At an equivalence ratio of 0.8333 the NO has and 17.490% Carbon Dioxide. The hydrocarbons measured 30 fallen sharply, however, the hydrocarbons were beginning to in this testing were not speciated to determine the exact rise sharply. This was an indication that the engine is at or makeup of the total. It is generally known that approxi near the lean limit of combustion. Although a continuous mately 80 to 90% of the total hydrocarbons are made up of reduction in the equivalence ratio yielded a sharp reduction methane hydrocarbons. The methane hydrocarbons are non photo-reactive and are generally not considered to be a 35 in This NO, the engine misfired.

test in Table 2 began at an equivalence ratio of 1.23.

significant pollutant. The NO was approximately 450 ppm. The NO climbed The NO, span gas bottle contained a liner to prevent any rapidly as the air to fuel mixture was leaned out. At an reaction between the gas and the bottle. The instrument was equivalence ratio of approximately 1.1 the NO had risen checked for Zero drift before and after each test. In addition, beyond the instrument capability. At stoichiometric (an the span was checked before and after each test sequence. equivalence ratio of 1) the NO is beginning to fall sharply Data was only accepted when both zero and span repeated and is reduced from that observed with no hydrogen added. within the limits of the instrumentation. As this mixture is leaned out further, the NO continues to The emissions pickup robe was amounted in the collector fall significantly, and the hydrocarbons again began to rise pipe 4 inches from the primary pipes. Only stainless steel sharply. However, the slope is less than that noted on the and Teflon tubing was used for exhaust gas delivery. pure natural gas.

TABLE 1.

Test 1).0% HYDROGEN AND 100% NATURAL GAS

TEST AF % EQUIV RPM HP ME TMNG TORQUE

AAA-2 16.5 O 104.24 1697 17 22 50 52.7

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

AAA-3 16.8 O 10238 1698 16.8 22 SO 52.9

AAB-2 17 O 1.0118 1698 22 49 52.5

AAB-3 12 O 1. 1698 17 22 49 52.5

AAB-1 17.3 O 09942 1698 17 22 49 52.7

AAC-2 18.7 O 0.9198 1700 1639 22 51 52.1

AAC-3 18.8 O 0.9149 1699 17 22 51 52.5

AAC-1 19.1 O O9005 1700 17 22 51 52.5

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

AAD-3 21.1 O 0.8152 1694 17.2 23 51 53.4

AAD-2 213 O 0.8075 1698 17.2 23 5 53.1

AAE-2 229 O OT511 1699 1. 22 56 529

AAE-3 23 O O.478 1TOO 17.3 23 58 53.5

AAE- 232 O 0.7414 1692 16.8 22 56 52.3

AAF-1 23.9 O 0.197 1699 15.5 2O 56 47.9

Page 30

TABLE 1-continued

Test 1) 0%. HYDROGEN AND 100% NATURAL GAS

AAF-2 24.3 O OTO78 104 16.1 21 56 49.5 AAF-3 24.4 O 0.7049 1704. 15.7 21 56 48.5

OL, H2O PPM PPM PERCENT A1-A2 NOX HC TEST TEMP TEMP NOX HC O2 SCFM g/HipHr g/Hip/Hr AAA-2 20 172 999 49.2 2.88 41.6 5.40 0.27 AAA-1 202 172 999 48.8 2.88 42 5,41 0.26 AAA-3 203 13 999 48.9 2.93 41.6 5.46 0.27 AAB-2 206 12 999 47.6 3.37 42.6 5.52 0.26 AAB-3 206 171 999 46.8 3.38 42.4 5.9 0.26 AAB-1 206 173 999 46.7 3.38 42.5 5.50 0.26 AAC-2 206 172 592.5 56.2 5.2 46.1 3.54 0.34 AAC-3 205 173 6038 58.7 5.19 46.3 3.60 0.34 AAC-1 204 173 608.9 55.2 5.1 46.2 3.62 0.33 AAD-1 204 172 1823 69.5 6,64 50.5 1.20 0.46 AAD-3 202 171 168.2 T2 6.79 5.5 110 0.46 AAD-2 203 172 183.5 68.4 6.64 59 1.21 0.45 AAE-2 202 171 52.6 116.6 8.35 58.8 0.39 0.87 AAE-3 202 172 SOT 115.5 8.34 59.2 0.38 0.86 AAE-1 203 171 569 115.8 8.32 59 0,43 0.88 AAF-1 199 172 32.1, 1844. 9.21 82.6 0.28 1.61 AAF-2 200 171 27.6 209.1 9.34 63.4 0.24 1.76 AAF-3 199 171 264. 21.3 9.33 83.2 0.23 184

TABLE 2.

(Test 2) 11% HYDROGEN AND 89% NATURAL GAS

TEST AF 9. EQUIV RPM HP ME TIMING TORQUE ABA-2 14.2 10.7 12324 100 7.1 22 35 52.7 ABA-1. 14.4 10.7 12153 103 17 22 35 52.4 ABA-3 14.5 10, 12069 1896 17.1 23 35 53.1 ABB-1 5.3 11.2 1.1438 1700 16.9 22 40 52.3 ABB-2 5.5 13 1.129 1699 16.8 22 40 52 ABB-3 15.6 11.5 1.1218 1699 17 22 40 52.4 ABC-3 17.2 118 10,174 1700 17 22 40 52.4 ABC-1 17.6 119 O9943 1699. 17.1 23 40 53 ABC-2 17.6 11.8 0.994.3 10O 1.1 22 40 52.7 ABD-1 19.6 117 O.899 1699 17.1 23 41 53 ABD-2 19.6 116 0.892.9 1697 17.1 22 41 529 ABD-3 19.6 116 0.892.9 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. 103 1.1 22 44 52.7 ABE3 209 116 0.833 17OO 1.1 22 44 52.7 ABF-3 22.9 115 0.642 1699. 17.2 23 45 53.2 ABF-1 23 115 0.609 1701 16.9 22 45 52.1 ABF-2 23.4 15 0.479 1699. 17.1 22 45 52.9 ABG-2 25.9 115 0.65 1701 17.1 22 55 52.7 ABG-1 28 115 0.6731 1706 7. 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/HipHr g/Hp/Hr ABA-2 22 172 469.2 60.8 0.51 37.8 2.31 O.30 ABA-1. 21 172 4549 6.1 0.5 38. 2.26 O3 ABA-3 212 172 491.7 61.3 0.52 37.9 2.42 O3O ABB-1 212 174 999.5 49.4 .28 38.1 5.00 O.25 ABB-2 212 174 999.5 50.8 .2 38.2 5.04 0.25 ABB-3 213 174 999.5 48.7 1.31 38.3 4.99 0.24 ABC-3 209 172 854.4 418 3.32 41.6 4.60 0.23 ABC-1 209 174 86.2 41.6 3.41. 4.1.8 4.66 0.22 ABC-2 209 74 862.2 42.2 3.35 42.1 4.67 0.23 ABD-1 208 173 2546 52.1 5.48 46.6 1.52 0.31 ABD-2 20 172 259.3 52.1 5.47 46 1.53 0.31 ABD-3 20 171 259.4 519 5.48 46.5 153 O.31 ABE-2 205 172 157.6 614 6.5 48.5 0.97 0.38 ABE-1 2O7 171 168.8 61.5 6,44 48.8 io.5 0.38 ABE-3 205 173 1737 60.6 6.41 48.7 1.08 O.38

Page 31

TABLE 2-continued

(Test 2) 11% HYDROGEN AND 89% NATURAL GAS

ABF-3 203 171 46.1 76.1. 8.02 55.3 O.32 0.53 ABF-1 206 172 44.8 76.5 8.06 55.1 O.32 0.54 ABF-2 205 171 43.4 77.2 8.05 55.5 0.31 0.54 ABG-2 202 171 23.2 138.2 9.59 63.7 0.19 1.1 ABG-1 204 171 23.4 142.6 9.65 63.9 0.19 1.15 ABG-3 202 172 24.3 140.6 9.6 63.5 0.20 1.13

Test 2 was terminated at an equivalence of 0.666. value of 0.625, where the test was terminated. The test was Although the engine did not appear to be at the lean limit, terminated because the engine again appeared to be missing the hydrocarbons had risen beyond acceptable limits. 15 and was apparently beyond the drivable limits. In Test 3 at stoichiometric, the NO is again beyond the In Test 4, at stoichiometric, the NO is again beyond the limit of the measurement instrumentation. At an equivalence limit of the measurement instrumentation and remained ratio of 0.95 (slightly lean) the NOfalls sharply. The NO beyond the limit of the instrumentation at an equivalence continues to fall as the equivalence ratio is reduced to a ratio of

TABLE 3

Test 3) 20% HYDROGEN AND 80% NATURAL GAS

TEST AF % EQUTV RPM HP ME TIMING TORQUE ACA-2 15 19.7 1.1833 1700 17 22 35 52.5 ACA-1 15.1 19.5 1.1755 1702, 17 22 35 52.4 ACA-3 15.3 19.8 1.1601 1705 17 22 35 52.4 ACB-2 17.7 19.8 10028 1699. 17.2 23 39 53.2 ACB-3 17.9 199 0.9916 1701 172 23 39 53 ACB-1, 18 19.8 0.9861 1698 17.3 23 39 534 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 0.9103 1699 17 22 43 52.6 ACD-2 20.7 199 0.8575 1696 17.1 22 45 529 ACD-1 2.1 2O 0.8412 1700 17.1 22 45 52.7 ACD-3 21.1 20 0.8412 1699 17 22 45 52.4 ACE-3 22.2 20 0.7995 1700 17 22 51 52.5 ACE-2 22.7 20 0.7819 1699 17.1 23 51 53 ACE-1 22.9 20 0.775 1698 17 22 51 52.6 ACF-2 24.8 20.1 0.7215 1697. 17.1 22 55 529 ACF-3 24.6 2O 0.7215 1698 16.9 22 55 52.3 ACF-1 25 20 0.71 1699 17 22. 55 52.7 ACG-2 26.1 2O 0.6801 1699. 17.1 22 59 529 ACG-3 26.6 2O 0.6673 1697 17 22. 59 52.6 ACG-1 27 2O 0.6574 1699 17 22. 59 52.7 ACH-1 27.9 2O 0.6382 1700 16 21 60- 49.3 ACH-2 28 20 0.6339 1709 16.5 22 60 50.6 ACH-3 28.1 2O 0.8317 1703 6.2 21 60- 499

OIL, H2O PPM PPM PERCENT A1+A2 NOX HC TEST TEMP TEMP NOX HC O2 SCFM g/Hip/Hr g/Hip/Hr ACA-2 212 172 827.5 52.7 O.81 37.5 4.05 0.26 ACA-1 213 174 824.7 54.9 0.83 37.5 4.04 0.27 ACA-3 212 174 827.6 53.3 0.82 37.6 4.06 O.28 ACB-2 210 172 999.5 41.1 3.81 42.1 5.38 0.22 ACB-3 210 172 999.5 41.8 3.68 42 5.36 0.22 ACB-1 212 172 999.5 41.1 3,63 42.3 5.37 0.22 ACC-1 20 173 775.1 47.3 4.86 44.8 447 0.27 ACC-3 209 173 773.3 46.6 4.89 44.3 4.41. 0.27 ACC-2. 210 73 802.7 46.9 4.84 44.7 4.82 0.27 ACD-2 206 173 292.5 55.6 6.19 47.3 1.77 0.34 AC)-1 207 172 300.7 55.6 6.16 47.3 1.81. 0.34 ACD-3 206 172 288.5 55.6 6.16 47.3 1.75 0.34 ACE-3 206 173 1899 665 742 50.3 1.22 0.43 ACE-2 205 172 200.2 65.8 7.35 51 1.30 0.43 ACE-1 206 171 2007 65.8 7.34 50.9 1.31 0.43 ACF-2 204 17O 67.9 81.1 8.63 55.1 0.47 0.57 ACF-3 203 171 66.8 81.7 8.68 55.2 0.47 O.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 60.2 0.27 0.73 ACG-3 202 171 34.3 96.7 949 59.7 0.26 0.73 ACG- 203 172 35.1 96.9 9,48 59.9 0.27 0.74

Page 32

TABLE 3-continued

(Test 3) 20% HYDROGEN AND 80% NATURAL GAS

ACH-1 200 171. 20.7 132.3 10.15 63.2 0.18 1.13 ACH-2 201 17, 20.6 13.9 0.15 64 0,1 1.15 ACH-3 200 172 19.9 137.2 10.19 64.3 0.17 1.7

TABLE 4

Test 4) 23% HYDROGEN AND 72% NATURAL GAS

TEST AWF % EQUIV RPM HP ME TIMING TORQUE ADA-3 15.3 28.1. 1179 1701 16.8 22 36 52 ADA-2 15.4 28.2 1.714 1700 169 22 36 52.1 ADA-1 15.5 28 1.1639 1703 16.8 22 36 519 ADB-3 16.6 28.1. 1088 1699 17 22 38 52.6 ADB-1 16.7 28.1. 10802 1702 17 22 38 52.4 ADB-2 16.7 28.2 0802 1702 17 22 38 52.5 ADC-1 1.7 28 1092 1702 17.2 23 39 53.1 ADC-3 7. 28.1 10192 1703 17.1 22 39 52.6 ADC-2 18 28.2 10022 1699. 17.3 23 39 53.4 ADD-2 19.1 28.2 09.445 1702 16:9 22 39 52.3 ADD-1 19.6 28.3 0.9204 1702 16.8 22 39 52 ADD-3 19.7 28.2 0.915 1703 17 22 39 52.4 ADE-3 21.5 28.3 0.8391 1701 17 22 41 52.6 ADE-1 21.7 28.4 0.8313 1700 17- 22 41 52.6 ADE-2. 21.8 28.4 0.8275 1703 17.2 23 41 53 ADF-2 23 285 0.843 1703 17.1 22 50 52.6 ADF-3 23.1 28.4 0.781 1702 17 22 50 52.6 ADF-1 23.2 28.4 0.776 1703 17.1 22 SO 52.6 ADG-2 24.8 28.5 0.274 1TOO 17 22. 52 52.5 ADG-3 249 28.5 0.245 1701 17.1 22. 52 52.6 ADG-1 25.2 28.5 O159 1703 T 22, 52 52.3 ADH-3 26.7 28.5 0.6757 1701 17.1 22 S4 52. ADH-2 26.8 284 0.6731 1701 17 22 S4 526 ADH-1 27.3 28.5 0.6608 103 17.2 23 S4 53 AD-1 28.3 28.5 0.6375 1701 17, 22 58 52.6 AD-3 28.4 28.5 0.6352 1698 16.8 22 58 52.4 AD-2 28.7 28.5 0.6286 1699. 17 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-3 209 173 999 52.3 0.9 38 5.01 O.26 ADA-2 209 12 999 52.7 0.89 37.8 4.95 0.26 ADA-1 20 173 999 54.6 0.88 37.8 4.96 O.27 ADB-3 209 172 999 34.7 2.06 39 5.06 O.18 ADB-1 210 173 999 34.8 2.01 39.3 5.09 O.18 ADB-2 211 171 999 34.6 2.04 39.3 5.09 0.18 AOC-1 209 172 999 35.2 3.38 4. 5.33 O.19 ADC-3 209 174. 999 36.8 3.38 4. 5.36 0.20 AOC-2 207 174 999 35.7 3.36 41.9 5.32 0.19 ADD-2 207 173 584.8 40.6 S 44 3.33 0.23 ADD-1 208 173 580.8 40.7 SO1 44.4 3.36 0.24 ADD-3 207 171 573.3 4.7 5 44.7 3.30 0.24 AE-3 204 172 252.6 53 6.54 48.6 1.57 0.33 ADE-1 203 171 2.56.1. 53.2 6,57 48.6 1.59 0.33 ADE-2 205 171. 257. 52.3 6,55 48.5 58 0.32 ADF-2 202 171. 208.4 62.6 7.53 512 1.36 0.41 ADF-3 203 172 220.6 61.6 7.53 51.4 1.45 0.40 ADF-1 202 12. 211.8 611 7.52 51.6 1.39 0.40 ADG-2 202 171 4, 72.4 8.59 55.1 0.52. 0.51 ADG-3 200 171 75.5 71.4 8.58 54.7 0.52 0.49 ADG-1 2O1 171 764 711 8.56 54.9 O.53 0.50 ADH-3 198 171. 26.9 82.5 9.54 60 * 0.2O O.63 ADH-2 200 172 2.3 83.1 9.54 60.1 0.21 0.63 ADH-1 199 171 27.3 83.1 9.55 60 0.21 0.63 AD-1 198 170 15.9 104.1. 10.27 63.6 0.3 0.84 AO-3 197 171. 16.7 104.2 10.27 63.8 0.14 0.85 AD-2 199 171. 16.5 104.4 10.27 63.8 0.13 0.84

0.95. When the air to fueiratio was leaned to an equivalence terminated at an equivalence ratio of approximately 0.625 of 0.87, the NO dropped sharply. The test was again where the NO was measured to be approximately 16.5 ppm.

Page 33

The engine was again observed to be missing although in cylinder pressure readings were not taken to confirm this fact. Notice that the hydrocarbons were found to be 104 ppm.

In Test 5 at stoichiometric, the NO levels were beyond 5 the measurement limit of the instrumentation. The NO levels dropped sharply at an equivalence ratio of 0.91. The

NO levels continue to fall to the termination of the test at approximately 0.625 equivalence ratio. The NO has a low value of approximately 12 ppm. The hydrocarbons have a 10 maximum value of 105 ppm. This is approximately the same as the hydrocarbons measured during the 30% hydrogen testing. The test was terminated before there was a sharp rise in the hydrocarbons thus indicating that the roughness was not being caused by running the engine beyond the lean 15 limit.

SUMMARY OF TESTS 1-5

The purpose of TESTS 1 through 5 was to determine if the

lean limit of Natural Gas can be extended by introducing

Hydrogen, H. The hypothesis used was that the leaner the engine could be run without going into lean misfire, the lower the NO would be while only incurring moderate increases in the Hydro Carbons, HCs. HCs were not con- 25 sidered to be a significant problem since HCs can be reduced using catalysts.

TABLE 5

(Test S) 36% HYDROGEN AND 64% NATURAL GAS

TEST AJF % EQUTV RPM HP ME TIMING TORQUE AEA-1 16 359 1.1475 1704 16.9 22 35 52 AEA-3 16 38 1.1475 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 1704 17 22 3 52.4 AEB-1 18.5 36.1 0.9924 1701 17 22 3 52.4 AEB-3 18.6 359 0.9871 1703 17 22 37 52.5 AEC-3 20 36 0.918 1703 17 22 38 52.4 AEC-1 20.3 359 0.9044 1706 16.9 22 38 52 AEC-2 20.5 359 O.8958 1705 17.1 22 38 52.8 AED-3 22 36 0.8345 1704 17 22 43 52.5 AED-1 22.1 35.9 0.8308 1702, 17 22 43 52.4 AED-3 22.2 35.9 O.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 O,788 1705 17. 22 44 52.6 AEE-1 23.4 359 0.7846 102 17 22 44 52.6 AEG-3 25 359 0.344 17O2 17 22 49 52.4 AEG-2 25.2 36 0.286 1703 17.1 22 49 52.6 AEG-1 25.5 35.9 0.72 1702 17 22 49 52.5 AEH-1 29.5 35.9 0.6224 1707 17 22 50 52.1 AEH-2 29.5 35.9 0.6224 1704 16.8 22 SO 519 AEH-3 29.5 36 0.6224 1703 17.2 22 50 529

OL, H2O PPM PPM PERCENT A1+A2 NOX HC TEST TEMP TEMP NOX HC O2 SCFM g/HipHr g/HipHr AEA-1 213 174 999 40.8 1.16 38 497 0.20 AEA-3 213 173 999 41.1 1.13 38.3 4.95 O.20 AEA-2 211 174 999 42.8 1.15 37.9 5.04 0.22 AEB-2 207 174 999 32.8 3.71 41.9 5.41 0.16 AEB-1 208 174 999 32.1, 3.7 4.8 5.39 0.17 AEB-3 207 173 999 33.1, 3.71 42.1 5.43 0.18 AEC-3 206 172 475.3 39.9 541 45.4 2.77 0.23 AEC-1 206 173 493.3 39.5 5.39 45.5 2.90 0.23 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 2.4 0.32 AED-1 203 172 387.9 50.1 6.69 48. 2.42 0.31 AED-3 204 172 395.5 50.1 6.68 48.8 2.47 0.31 AEE-3 201 171 204.1 58.4 7.53 51. 1.33 0.38 AEE-2 203 172 206.7 58.2 7.54 51.2 1.34 O38

Page 34

TABLE 5-continued

Test 5) 36% HYDROGEN AND 64% NATURAL.GAS

AEE-1 203 173 202.6 58.4 7.58 51 1.32 0.38

AEG-3 200 172 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 10.63 64.8 0.10 0.87

AEH-2 198 172 11.7 104.1. 10.64 65 0.10 0.87

AEH-3 199 172 119 102.7 10.6 649 0.10 0.83

FIGS. 1 through 20 show partial maps of the NO and possible problems related to storage and safety. However, hydrocarbon emissions at various levels of hydrogen in 15 the specific mixture amounts of between approximately 21 Natural Gas and at various equivalence ratios. and 50%. Hydrogen, can be further narrowed down by Both 28% hydrogen and 36% hydrogen mixtures yielded engine size (46.8 cylinders) and regulatory concerns. very low NO levels a to 0.625 equivalence ratio. See FIGS. While natural gas has been referred to as including 13-20. The extremely low NO levels of 28 ppm (0.21 primarily methane, natural gas can include other compo gm/hphr) and 12 ppm (0.10 gm/hphr) respectively were 20 nents is much smaller amounts. Besides primarily contain unexpected. Recall that all of the emissions readings were ing methane, natural gas can include Carbon Dioxide, taken at the exhaust manifold outlet. There were no emission Nitrogen, Ethane, Propane, Iso-Butane, N-Butane, Iso control equipment on the tested engine and there was no Pentane, N-Pentane, and Hexanes Plus.

catalytic converter. The levels of NO at 28% and 36% While the tested engine did not use a catalytic converter, hydrogen mixtures were substantially below the strictest air 25 one could be added. The hydrocarbon levels at 28% and 36% quality standards. For example, current air quality standards hydrogen at an equivalence ratio of 0.625 were both in Japan require NO emissions to be below 200 ppm. This approximately 104 ppm (0.84 gm/hp hr). Since approxi standard is extremely difficult to meet and has never been mately 15% of the hydrocarbons are photo reactive the total met without substantial emissions control equipment on the reactive hydrocarbons are approximately 16 ppm (0.13 engine, based on the prior art known to the inventors. 30 gm/hphr.). This level of hydrocarbon emissions is extremely Referring back to FIGS. 2 and 4 for 0%. Hydrogen. low and there is the potential of reducing the total hydro Although at an equivalence ratio of 0.75 the NO level fell carbons to near zero through the use of a catalytic converter, significantly the hydrocarbons increased at approximately Mixtures of hydrogen and natural gas can be mixed by the same rate thus indicating an unstable operating condi known methods such as but not limited to sonic mixing, or tion. This same result can be noted in FIGS. 6 and 8 (11% 35 merely injecting hydrogen into natural gas, or injecting Hydrogen) and in FIGS. 10 and 12 (20% Hydrogen). natural gas into hydrogen.

However, the lean limit extends from approximately 0.75 While the alternative fuel mixture in this invention has equivalence ratio at 0% hydrogen to 0.67 equivalence ratio been successfully used with existing combustion engines, at 20% hydrogen. It is not feasible to operate the engine at modifications on existing engines can be accomplished in these lean limits since a very small change in the air fuel order to enhance engine performance such as horsepower. ratio will make a very significant increase in the NO levels For example, the alternative fuel disclosed herein can be or a very significant increase in the hydrocarbon levels. used in combustion engines include but are not limited to When the hydrogen concentration was extended to 28% turbocharging, engine settings (ignition, sparkplugs), there is no longer a point where the hydrocarbons abruptly camshafts, intake manifold and cylinder head modifications, increase as was seen at all lower levels of hydrogen thus 45 compression ratios, and injection system and combinations making lean burn a viable option. This same result was noted thereof.

at concentrations of 36% hydrogen as seen in FIGS. 17 and While the invention has been described as being used for

mobile vehicles such as an eight (8) cylinder automobiles,

The test results demonstrate that extremely low levels of the invention would have applicability to various other size NO are possible with acceptably moderate increases in engines such as four (4), six (6), and twelve (12) cylinder unburned hydrocarbons using 28% and 36% hydrogen mobile engines.

supplementation. Previous research conducted at 20% Furthermore, the disclosed invention can be used with hydrogen did not indicate a significant enough reduction to other size engines such as but not limited to lawnmower consider the mixture of hydrogen and natural gas as a viable engines, trucks, vans, aircraft and trains. solution to the problem of producing extremely low NO 55 levels of 20% and below. The significant reduction in NO VARIABLE AR/FUELRATO THROTTLE was realized when the hydrogen level was raised to approxi CONTROL mately 30% and the engine was run nearer the lean limit. In This portion of the invention covers a variable airlfuel addition, the lean limit of combustion was significantly ratio control that optimizes emissions and power output for extended by the increased levels of hydrogen. The NO lean burn applications. FIG. 21A and 21B is a Flow chart levels reported are an order of magnitude below the strictest showing a preferred operation of the throttle control inven current requirements. This level of NO was achieved with tion. FIG. 22 is a schematic diagram showing a preferred out a catalytic converter or other emissions reducing hard system control connections for using the throttle control ware on the engine. invention. Before discussing these Figures, a background for The tests and related data demonstrate that levels up to 65 this invention will now be discussed. approximately 50% Hydrogen can be used with combustion Test results have indicated that Spark Ignition (SI) engines. Over 50% Hydrogen gas in the mixture could create engines can operate at an equivalence ratio of approximately

Page 35

0.5 with approximately 35% by volume hydrogen in meth ane. The emissions during this test were NO of approxi Re=

mately 8 ppm and HC or approximately 845 ppm. This test c

was conducted on the engine previously discussed. Maxi mum engine horsepower was 93 at an equivalence ratio of 5 Step 200 of FIG. 21A goes to the top of FIG. 21B. Step approximately 0.625 while maximum horsepower was 24 at 210 is to calculate 8 which is equal to the desired air fuel, an equivalence ratio of 0.5. Thus, the optimum equivalence AF minus actual air fuel, AF Step 220 holds if 8-0 and ratio is a function of desired emissions, and horsepower. Z<1.0 at box 222 there is is no change go to step 100. If &=0 Varying the equivalence ratio dynamically will provide a and Z21.0 there is more cylinder pressure variation than is normally expected. Go to step 224 to increase Pw, the pulse vehicle with needed horsepower while minimizing the emis width sions from the vehicle. The optimum equivalence ratio is engineofalarm, the injector which will increase fuel, and set an 226 which can be a warning dashboard light thus a function of the percentage of hydrogen enrichment, that the engine is malfunctioning and that the driver should selected NOx (Noxious Oxide) and HC (Hydro Carbon) check the engine. If 8<0, go to step 232 and increase Pw levels, engine design configuration (cylinder size, cylinder 15 which will increase fuel to the engine and then go to step displacement, head dimensions, and the like) as well as 100. If S is not <0 go to step 240 and check Z. If Z31 go to desired power output. step 242 and reduce the amount of fuel to the engine, lower A system optimized for these parameters (hydrogen Pw, and then go to step 100. IfZ is not <1 go to step 250 enrichment, NOx, HC, engine design) will produce less reduce Pw and set engine alarm 260 that engine is malfunc power than could be produced if the engine were operated 20 tioning and then go to step 100.

approximately at stoichiometric. With this system, the emis FIG. 22 is a schematic diagram showing a preferred sion levels of NOx, and controlled HC's will be on the order system of the control connections for using the throttle of approximately 25 ppm or less. In addition the CO output control algorithm of FIGS. 21A and 21B with the internal will be on the order of approximately 1% of less. These combustion engine 10 in a mobile vehicle. Air is inducted levels of emission would qualify the vehicle for ULVE 25 through the intake manifold 1 and the volume can be (Ultra Low Vehicle Emission) status as established by the measured by sensor 2 whose output is sent to control unit 14 California Air Resources Board (CARB). The system for a computer that runs the algorithm flow chart depicted introducing fuel and air into the engine can utilize either a previously in FIGS. 21 A and 21B. The position of the carburetion system or a fuel injection system as described throttle blade can be determined by sensor 3. Sensor 3 can previously in the background section of the invention. 30 be configured such that when the throttle blade is fully open However, the prior art systems are still limited because (parallel to intake air) the additional travel of the throttle can additional power would be required for severe grade occur to indicate an operator (drivers) desire for increased climbing, expressway merging and passing. In the prior art power. Component 4 can be the fuelinjector whose Pw pulse systems a wide open throttle could still cause the engine to width is controlled by control unit 14. As the pulse width to not produce sufficient powerfor these extreme conditions. In 35 injector 4 is increased, the air fuel ratio (b) can be increased. the subject invention, the air/fuel ratio can be shifted during Component 5 is the mass fuel flow sensor which also the wide open throttle toward stoichiometric. Thus, in the provides input for control unit 14. Component 6 is the instant invention, the air/fuel ratio is shifted toward stoichio emission sensor which can monitor NO, CO, CO, THC, metric as a function of the instantaneous power demand. NMOG and O, passing into muffler 12. Sensor 7 is the The novel throttle control can use a "carburetor' or "fuel engine 10 temperature sensor. Sensor 8 is the crank angle sensor used to determine engine 10 speed and which of the injection” system. For a carbureted system, a secondary cylinder(s) is being fired. Sensor 9 is thein-cylinderpressure demand regulator system can be operated in parallel with the transducer for engine 10. For each cylinder of the engine, standard demand regulator system. The standard demand regulator system can be adjusted to maintain an optimal 45 there is a separate in-cylinder transducer 9. Control unit 14 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 (H2) 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.

SO 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, H2, can be stored either in system, the standard electronic control unit (ELU) such as 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 55 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 H2 can step 110 is to calculate engine speed (rpm) N. mass airflow be varied dynamically and controlled by control unit 14 as Q, and mass fuel flow F. Step 120 is to calculate throttle a function of output emissions and engine power. The algorithm in our invention will maintain the airlfuel position T, velocity of throttle position dT/dt, and accel ratio at the optimum for emission while the engine power is eration of throttle position d'Tp/dr. Step 130 is calculate 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 approximately d=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 Qand F. Step 160 is to calculate in-cylinder 65 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 airlfuel

Page 36

ratio can be automatic where the driver is unaware of the 4. The method of claim 1, wherein the mobile vehicle change. Alternatively, the system can require additional engine further includes:

force on the throttle pedal to alert the driver that the vehicle running an automobile.

is now being operated in less than the optimal range. 5. The method of claim 1, wherein the mobile vehicle Although the control algorithm embodiment and sche 5 engine further includes:

matic has been described for use with a hydrogen gaseous running a lawnmower.

fuel, the invention would have applicability to other types of 6. The method of claim 1, wherein the mobile vehicle mobile vehicle fuels that can support an extreme lean burn engine further includes:

condition. running a train.

While the invention has been described, disclosed, illus 10 7. The method of claim 1, wherein the operating step trated and shown in various terms of certain embodiments or further includes:

modifications which it has presumed in practice, the scope operating at an air and fuel equivalence ratio of approxi of the invention is not intended to be, nor should it be mately 0.6.

deemed to be, limited thereby and such other modifications 15 8. A method for producing lean burn (below or embodiments as may be suggested by the teachings herein stiochometric) and low NOx emission rates for an internal are particularly reserved especially as they fall within thecombustion engine of a mobile vehicle using an alternative breadth and scope of the claims here appended. hydrogen and natural gas mixed fuel to achieve a lean burn We claim:

condition (below stoichometric) without regard to the burn 1. A method for producing lean burn (below and emission rates of gasoline, comprising the steps of: stoichometric) and low NOx emission rates for an internal 20 feeding an alternative gaseous fuel mixture of approxi combustion engine of a mobile vehicle using an alternative mately 28 to approximately 50% hydrogen gas and the hydrogen and natural gas mixed fuel to achieve a lean burn remainder being natural gas to an internal combustion (below stoichometric) without regard to the burn and emis engine of a mobile vehicle; and sion rates of gasoline, comprising the steps of: 25 operating the vehicle engine at an air and fuel equivalence feeding an alternative gaseous fuel mixture of greater than ratio of less than 1.0 (stoichometric); and 21% up to approximately 50% hydrogen gas, and the emitting near ZeroNOx emissions from the vehicle engine remainder being natural gas to an internal combustion to achieve a lean burn without misfiring the engine. engine of a mobile vehicle; and operating the internal 9. The method of claim 8, wherein the emitting step combustion engine at lean burn having an air and fuel 30 further includes:

equivalence ratio of approximately 0.6; and emitting hydrocarbon emission levels of less than emitting near zero NOx emissions below approximately approximately 104 ppm (0.84 gm/hphr). 104 ppm (0.84 gm/hphr), without misfiring the engine. 10. The method of claim 8, wherein the fuel mixture 2. The method of claim 1, wherein the natural gas further includes:

includes at least one constituent selected from: 35 approximately 28 to approximately 42% hydrogen gas Methane, Carbon Dioxide, Nitrogen, Ethane, Propane, and the remainder being natural gas. Iso-Butane, N-Butane, Iso Pentane, N-Pentane, and 11. The method of claim 8, wherein the operating step Hexanes Plus. further includes:

3. The method of claim2, wherein the hydrogen gas in the operating the vehicle engine at an air and fuel equivalence mixture includes: 40 ratio of approximately 0.6. approximately twenty-eight (28) to approximately forty two (42) percent hydrogen. ck k . . .