Method and apparatus for injecting hydrogen into a catalytic converter

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Modes of Operation for an Ideal CHC System

sk Safety monitoring sk System status sk Sleep

START

sk System status sk Converter temperature

sk Start air pump sk Release H2 until: O time

O temperature

O volume (pressure) sk Safety monitoring sk System status

sk Safety monitoring sk System status

RESTORE H2 SUPPLY

sk Electrolyze sk Control current draw sk Safety monitoring sk System status sk Monitor:

O Pressure

O Temperature

SYSTEM MAINTENANCE

sk Recover cathode water sk System status sk Safety monitoring

RETURN TO PRE-START

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METHOD AND APPARATUS FOR for the catalyst to work efficiently, is generally referred to as INJECTING HYDROGEN INTO A the light-off time. Light-off temperature is generally defined CATALYTIC CONVERTER as the temperature at which fifty percent (50%) of the emissions from the engine are being converted as they pass

BACKGROUND OF THE INVENTION through the catalyst.

1. Field of the Invention The conventional method of heating the catalytic con The present invention relates generally to the field of verter is to heat the catalyst by contact with high temperature catalysis for the reduction of emissions from internal com exhaust gases from the engine. This heating, in conjunction bustion engines. More particularly, the present invention with the exothermic nature of the oxidation reaction occur relates to a method and apparatus for heating a catalyst by ring at the catalyst, will bring the catalyst to light-off Spontaneous combustion of hydrogen introduced into the temperature. However, until the light-off temperature is catalyst. More particularly Still, the present invention relates reached, the exhaust gas passes through the catalyst rela to the conditioning through preheating of a Standard three tively unchanged. In addition, the composition of the engine way or two-way catalytic monolith in a vehicle powered by 15 exhaust changes as the engine heats from the cold Start an internal combustion engine, Such as an automobile. temperature, and the catalyst is designed to work best with 2. Background of the Related Art the composition of the exhaust Stream present at the normal The control and Suppression of unwanted emissions cre elevated engine operating temperature.

ated by the operation of an internal combustion engine is a There have been several attempts to shorten or avoid the primary consideration for engine designers and vehicle time between cold Start and light-off of the catalytic con manufacturers because of nearly world-wide governmental verter. Current techniques employ one or more of the requirements regarding acceptable emissions levels. Over following methods: electrical heating of the exhaust gases eighty percent (80%) of the unacceptable emissions or and/or of the catalytic converter itself; thermal insulation; pollutants created by internal combustion engines equipped multi-chambered configurations of the catalytic converter; with catalytic converters occur during cold Start operations. 25 and/or placing the catalytic converter adjacent to the engine for heating. All of these methods have drawbacks and

These pollutants are emitted for a period of one to three limitations.

minutes after cold engine Starting, in large part because that is the time period required for the catalyst to reach an Placing the catalytic converter almost immediately adja effective and efficient operating temperature. Therefore, cent to the engine is not feasible because of the tendency to even though the engine exhaust is flowing through the overheat the catalyst with resulting accelerated degradation catalytic converter, until the exhaust heats the catalytic of the catalyst. Thermal insulation is also not an acceptable converter to its operating range from engine Start up, the option because of the same problems, especially during exhaust gases are only slightly catalyzed during that time operation under maximum operating temperature ranges. period. Electrical heating of catalytic converters (“EHC) has In order to meet governmental emission Standards for 35 been a popular proposed method of attempting to preheat the internal combustion engine exhaust, a catalytic converter is catalyst monoliths. Limitations on the equipment and located in the exhaust Stream of the engine. The converter process, however, affect the utility of this method. The typically includes a canister holding a Suitable catalyst, Such primary limitation on electrical preheating is the electrical as a three-way catalytic converter (TWC) catalyst monolith, energy required by the heater. The typical car battery is not that will oxygenate unburned, unacceptable components in 40 a practical power Source to Supply the electrical power the exhaust stream including hydrocarbons (HC), their par because the electrical load on the vehicle battery during the tially oxidized derivatives Such as aldehydes and carbon period required may exceed the rated battery output. In any monoxide (CO), and at the same time reducing nitrogen event, the load placed on a typical 12 volt vehicle battery oxides (NO), after almost stoichiometric fuel burn with will shorten the lifetime of the battery. Also, there is a oxygen in the cylinders of the engine. The exhaust gas is 45 measurable delay between the time the operator of the passed through the catalyst monolith, thereby completing vehicle places the ignition Switch in the “on” position and the oxygenation of unburned HC and CO, and the reduction the time the heater brings the catalyst to light-off tempera of NO in the exhaust to convert these unacceptable emis ture.

Sions into acceptable emissions. Certain unacceptable emis Typically, in the interval between Start up and light-off, Sions in the exhaust Stream, including unburned hydrocar 50 the exhaust Stream is oxygen deficient. Because the catalyst bons and carbon monoxide, require an oxidation reaction to requires oxygen to complete the catalytic reaction, Supple destroy them So that they end up as the corresponding mental air must be blown over the catalyst. Even when using oxides, e.g., water and carbon dioxide. On the other hand, a Secondary air flow to overcome oxygen deficiency, the NO requires a reduction reaction to develop N2 and O. In Secondary air flow must be closely controlled to avoid an fact, the O product of this reduction contributes to the 55 excess of oxygen, in which case the catalytic converter is oxidation of the HC and CO in the exhaust. less effective in reducing NO. However, it should be noted TWC catalysts are currently formulated and designed to that NO contributes a very small portion of unacceptable be effective over a specific operating range of both lean and emissions when an engine is cold; most of the emissions that rich fuel/air conditions and a specific operating temperature must be dealt with comprise HC, CO and the like. range. These particulate catalyst compositions enable opti 60 An alternative to battery powered electrical heating has mization of the conversion of HC, CO, and NO. This been to decrease the Strain on the power Supply by Supplying purification of the exhaust Stream by the catalytic converter the power directly from an alternator rather than directly is dependent on the temperature of the exhaust gas and the from the vehicle battery. An alternator powered, electrically catalytic converter works optimally at an elevated heated catalyst (“APEHC”) still requires a 5 to 10% increase temperature, generally at or above about 300° C. The time 65 in battery capacity to cope with the EHC Start-up Scenario. span between when the exhaust emissions begin (i.e., “cold Even with the APEHC system, there still is a concern with start”), until the time when the substrate heats up sufficiently respect to battery capacity because electric heating is needed

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for an extended period of time, i.e., more than 25-30 for introducing hydrogen may comprise a manifold within or Seconds. In addition, the maximum alternator power output outside the canister.

required in the APEHC System requires a complicated Yet another aspect of the invention provides a catalytic Switching mechanism and an altered alternator Speed converter System for the exhaust of an internal combustion between 2,000 and 4,500 rpm during the heating up time engine with an exhaust line, comprising: a catalytic con period, and the alternator must be oversized. verter in the exhaust line; a Source of hydrogen; a conduit The multi-chamber configurations of catalytic converters connecting the Source of hydrogen to the exhaust line generally conform to one or two theories. In one multi upstream of the catalytic converter; a Source of oxygen; chamber configuration, a Small portion of catalyst known as means for controlling the introduction of hydrogen from the a “starter catalyst” is positioned upstream from the primary Source of hydrogen to the exhaust line, means for controlling catalyst. This “starter catalyst” is generally closer to the the introduction of oxygen from the Source of oxygen to the exhaust manifold. This location, in conjunction with a exhaust line, independent of the means for controlling the Smaller thermal mass associated with its Smaller size, causes introduction of hydrogen; an isolation valve in the exhaust the catalyst to heat much more quickly than a single catalyst. line upstream of the catalytic converter; and an isolation This configuration, however, is generally unacceptable 15 Valve in the exhaust line downstream of the catalytic con because the Starter catalyst in the exhaust Stream creates a Verter.

higher back pressure which reduces the overall engine The present invention also provides a heater for the efficiency and robs the engine of power output. passenger compartment of a vehicle, comprising: a heat Another method of providing multiple chambers in the eXchanger defining a first path for the flow of air to the exhaust flow includes a first catalyst having low temperature passenger compartment and a Second path, isolated from the characteristics used only during cold Start conditions, and, first path, for the flow of hydrogen and oxygen gases, a after the catalyst temperature rises to a Selected elevated catalytic converter in the Second path; and means for intro level, the exhaust gas flow is Switched to pass through the ducing hydrogen and oxygen into the catalytic converter. conventional catalytic converter configuration. A variation 25 BRIEF DESCRIPTION OF THE DRAWINGS of this approach is to run all cold Start emissions through a

Separate absorber (Such as a Zeolite or a molecular sieve So that the manner in which the above recited features, type Substance) where unacceptable emissions are captured advantages and objects of the present invention are attained and later released back into the exhaust Stream. This method, and can be understood in detail, a more particular descrip however, is impractical because of the complicated Switch tion of the invention, briefly summarized above, may be had ing mechanism used to divert flow to the absorber, the size by reference to the embodiments thereof which are illus and Space requirements of the absorber, and the impracti trated in the appended drawings.

cality of releasing the unacceptable emissions from the It is to be noted, however, that the appended drawings absorber back into the exhaust stream. illustrate only typical embodiments of this invention and are Finally, one method runs the engine excessively rich in 35 therefore not to be considered limiting of its Scope, for the the cold Start condition and ignites the resulting Super-rich invention may admit to other equally effective embodi mixture to directly heat the catalyst. This approach has mentS.

proved wholly unreliable and has other Serious drawbacks, FIG. 1 is a Schematic diagram of the apparatus of the including reduced engine and catalyst life. present invention for heating a catalytic converter; To date, there has not been a catalytic converter heating 40 FIG. 2 is an exploded view of a preferred electrolyzer that System which gives almost instantaneous heating of the may be employed in the present invention; catalytic converter without the inherent drawbackS Stated FIG. 3 is a Schematic of a hydrogen capturing and above. Thus, there remains a need for an improved catalytic handling detail of the System of the present invention. converter System that reduces ineffective catalytic action FIG. 4 is a sectional view of a simplified representation of immediately after cold Start-up of an engine. Such a System 45 a catalytic converter monolith showing air and hydrogen must be simple and must not reduce the rated lifetime of the flow in the axial direction;

engine, the catalytic converter, or the battery components of FIG. 5 is a sectional view of a simplified representation of the vehicle.

a catalytic converter monolith showing air and hydrogen

SUMMARY OF THE INVENTION

flow in the radial direction;

The present invention provides a catalytic converter SyS FIG. 6 is a graph of the catalyst temperature measured at tem for the exhaust of an internal combustion engine with an axial positions within the monolith as indicated in FIG. 5. exhaust line, comprising: a catalytic converter in the exhaust FIG. 7 is a graph of the catalyst temperature measured at line; a Source of hydrogen; a conduit connecting the Source radial positions within the monolith as indicated in FIG. 4. of hydrogen to the exhaust line upstream of the catalytic 55 FIG. 8 is a Schematic diagram of the apparatus of the converter, a temperature Sensor in the catalytic converter; present invention depicting a System for the combustion of and means for controlling the introduction of hydrogen from hydrogen for cold Start-up assist for an internal combustion the Source of hydrogen to the exhaust line, based on a engine.

temperature Sensed by the temperature Sensor. FIG. 9 is a Schematic diagram of a System having oxygen Another aspect of the invention provides a catalytic 60 recovery and Storage equipment providing for injection of converter in the exhaust line of an internal combustion oxygen into the catalytic converter. engine, comprising: a canister, a plurality of catalytic mono FIG. 10 is a Schematic diagram of a System having the air liths within the canister; a Source of hydrogen; a gap pump replaced with a venturi for drawing air into the between each of the plurality of monoliths, and means for catalytic converter.

introducing hydrogen from the Source of hydrogen into the 65 FIG. 11 is a control diagram of a prototype System using canister upstream of the plurality of monoliths and into the a microprocessor controller to monitor and control various gap between each of the plurality of monoliths. The means functions of the System.

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S 6

FIGS. 12(a) and (b) are graphs of the catalyst temperature The next major component of the hydrogen Source is the at various axial and radial distances in the catalyst monolith electrolyzer 50, shown in greater detail in FIG. 2. In the over a period of 50 Seconds using a pulsed release of following description of the electrolyzer 50, the materials of hydrogen into an air Stream. construction referred to as “preferred” are the material FIG. 13 is a graph of the hydrogen Storage tank pressure actually used in a test device to prove that the invention after a Series of pulsed releases in accordance with FIG. 12. would work for its intended purpose. In commercial pro FIG. 14 is a Schematic diagram of a heat eXchanger duction models of the present invention, where possible, leSS having a catalyst formed on one member receiving hydrogen expensive materials will be used throughout, Such as carbon and oxygen and another member being Suitable for the Steel for titanium where possible, and plastic Such as passage of air for cabin circulation. polypropylene where heat and StreSS will permit the use of Such material.

FIG. 15 is a Schematic diagram of a catalytic gas heater The electrolyzer 50 may be referred to herein as a proton for a diesel engine.

FIG. 16 is a Schematic diagram of an electrolyzer having eXchange membrane exchange (PEM) electrolyzer 50. The proton a thermal management cell for heating or cooling the 15 environment in contactitself membrane with may prove corrosive in this certain Substances, thus requir electrolyzer using liquid from a vehicle radiator. ing the careful Selection of the material of construction of the FIGS. 17(a) and (b) are catalyst monoliths having a electrolyzer. For example, the PEM should only contact hydrogen distributor. carbon or graphite. However, those of skill in the art will FIG. 18 is a Schematic diagram of a catalytic converter readily recognize where leSS exotic materials than those having isolation valves allowing hydrogen or oxygen to listed in the following discussion that are located away from diffuse evenly throughout the monolith before delivery of the PEM material itself and the oxygen electrode catalyst another gas to provide a catalytic combination mixture. can be readily employed without penalty. For example, FIGS. 19(a), (b) and (c) are schematic diagrams of three graphite will be the material of choice in certain Structural electrical Systems for providing electrical power to the 25 elements, and not Some obvious candidates Such as copper, electrolyzer. aluminum, or iron, which can corrode thus forming ions that FIG.20 is a flowsheet showing the modes of operation for can poison the oxygen and/or hydrogen electrode catalysts. an ideal chemically heated catalyst (CHC, a trademark of Now referring to FIG. 2, the PEM electrolyzer 50 is Lynntech, Inc. of College Station, Tex.) System. shown as a cell Stack including a pair of endplates 60 and 62. FIG. 21 is a Schematic diagram of a preferred configura The endplates 60 and 62 are preferably titanium and mea tion of the cabin heater. sure 4.2"x4.2"x24". Adjacent the top endplate 60 is an anodic cell frame 64. The cell frame 64 is preferably a carbon

DETAILED DESCRIPTION OF A PREFERRED fiber-filled Teflon sheet, sold under the trademark EMBODIMENT ZYMAXX by Du Pont. The cell frame 64 retains a 1:1 molar The present invention provides a method and apparatus 35 ratio of iridium and ruthenium dioxides (IrO/RuO) as the for chemically heating by feeding hydrogen to a catalyst. anodic electrocatalyst. The cell frame 64 also includes a The invention also provides a method and apparatus for plurality of flow ports 66 to permit the Supply of reactant thermally conditioning a catalyst in order to enhance the (water) and/or removal of electrolysis product (oxygen gas). conversion of unacceptable emissions emanating from an Below the cell frame 64 is an expanded titanium metal internal combustion engine into water and other acceptable 40 current collector (flow field) 68, preferably 25 Ti 40-3/32 emissions. In one aspect of the invention, hydrogen is from Exmet Corp. An anode substrate 70 is preferably a Supplied from an electrolyzer or other hydrogen Source and porous titanium plate measuring 2.49"x2.49"x0.05". Below injected into the monolith of a catalytic converter to more cut the anode substrate 70 is a proton exchange membrane 72, rapidly bring the catalyst to a light-off temperature. from a sheet of NAFION 117 from Du Pont which serves FIG. 1 shows a system 10 of the present invention 45 as a solid electrolyte material and which is 175 um thick. installed on a vehicle exhaust System. The vehicle includes FIG. 2 depicts a gasket 74, one of perhaps Several a catalytic converter 11 located in an exhaust line 42 from a installed where required. Gaskets 74 are stamped from vehicle's exhaust manifold, as shown. The exhaust line 42 is 0.033" thick fluorosilicone sheet (VITON) and from 0.005" provided with air from an air pump 44 and hydrogen from includesthick unsintered PTFE sheet. The electrolyzer 50 further a hydrogen inlet line 46. The air pump could be any Suitable 50 a cathode Substrate 76 like the anode Substrate 70 air Source, Such as a receiver, for injecting air into the and an expanded titanium flow field 78. exhaust line at Suitable pressure and Volumetric flow rate to Finally, the PEM electrolyzer 50 includes a cathodic cell achieve the ideal air/hydrogen ratio mixture. frame 80 formed of polychlorotrifluorethylene (PCTFE) The hydrogen Supply System of the invention generally sheet, sold under the trademark KEL-F by Afton Plastics. includes a water reservoir 48, an electrolyzer 50, and a 55 The cathodic cell frame 80 retains a fuel cell gas diffusion hydrogen storage cylinder 52. As shown in FIG. 1, the electrode containing high Surface area colloidal platinum, electrolyzer 50 may preferably compromise a plurality of Supported on platinum black, having platinum loading of 4.0 stacked identical cells 51. The reservoir 48 serves both as a mg/cm as the cathodic electrocatalyst layer. water reservoir and as a separator for oxygen and water. The As shown in FIG. 2, the various components of the PEM reservoir 48 may be a vehicle's windshield washer fluid 60 electrolyzer are Stacked together and retained with a plural Storage container, but is preferably a dedicated Separator ity of tie rods 82, preferably 16 Such tie rods. Stainless steel allowing collection and Storage of oxygen via port 54. Water tubing, such as SS316, are then screwed into four threaded flows by gravity drain or is pumped from the reservoir 48 to ports on one of the titanium endplates. The ports are the the electrolyzer 50 via a drain line 56. As the electolyzer water inlet port 56, the oxygen outlet port 58, and a pair of produces hydrogen and oxygen, the oxygen and entrained 65 hydrogen outlet ports 84. To minimize electrical contact water flows naturally back to the reservoir 48 via a return resistance, the titanium endplates 60 and 62 and the line 58. expanded titanium metal current collectors 68 and 78 may

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be electroplated with a thin film of gold or other noble 104. The electrolyzer typically operates at about 20 C. metals, Such as platinum. above ambient, with the exact temperature depending on The cathode and the anode of the electrolyzer are of Specific electrolyzer operating conditions. This Second Step Special construction. The cathodic electrode Structure for condenses a Substantial portion of the water vapor in the hydrogen evolution is fashioned from a commercially avail hydrogen gas Stream. This condensed water could absorb a able fuel cell gas diffusion layer on a carbon cloth backing, Significant amount of alcohol, which may be present during which acts as a Support for the active hydrophilic electro operation using windshield washer fluid as the electrolyzer catalyst layer. This active layer contains high Surface area reactant feed. The condensate is collected in a condensate colloidal platinum (100 m/g), supported on carbon black collector 106 and removed through a drain valve 108. (60 wt % Pt on C), yielding a platinum loading of 4.0 At this point, the hydrogen gas Stream is still Saturated mg/cm. The cathodic electrode structure, having an area of with water vapor, but now at a lower temperature. This 40 cm, was hot-pressed onto one side of a segment of Saturated gas Stream is next passed into a Zeolite-filled gas precleaned NAFION 117 PEM material. Hot-pressing was drier 110. This drier absorbs water vapor and any alcohol carried out between the plates of a hot-press elevated to 200 Vapor present when using a windshield washer fluid feed. C. for 60 seconds, and using a force of 15,000 pounds. 15 Any oxygen contaminant present in the hydrogen gas Stream For the anodic electrocatalyst layer, a 1:1 molar ratio of is then eliminated in a catalytic recombiner or oxygen iridium and ruthenium chlorides are dissolved in ca. 8 ml of eliminator 112 to reduce it to water. Final clean-up of the concentrated HCI and heated to almost dryness. The result hydrogen gas Stream is accomplished in a Second Zeolite ing chlorides are then dissolved in isopropanol to make an absorber bed in a polishing drier 114. The polishing drier ink-line coating. A porous titanium plate, 0.05" in diameter removes traces of water produced by the catalytic recom from Astro Met of Cincinnati, Ohio, is etched in 12% HBF biner 112.

for 60 seconds and rinsed with isopropanol. This substrate is The hydrogen gas handling System of FIG. 3 is designed then coated with the ink-like mixture and the Solvent evapo for relatively short term operation; longer term operations, rated under low heat of about 90° C. This coating and drying 25 for example 100,000 miles, would utilize other methods of procedure is repeated Seven times, then the electrode is water removal known in the art. A Satisfactory metal hydride heated in a furnace at 400° C. for 10 minutes in ambient air. hydrogen Storage unit is available from Hydrogen Consult The coating, drying, and furnace treatment is repeated twice ants of Littleton, Colo. Such an available unit can store 30 more, but with a final baking time of two hours instead of 10 liters of hydrogen which can be delivered at 30-45 psig, minutes. with recharging using hydrogen gas at 100-200 psig. More Referring back to FIG. 1, the system further includes a preferably, the hydrogen Storage vessel is a pressure vessel hydrogen Storage cylinder and various Supporting compo made of a composite Structure, aluminum or ferrous-based nents in addition to the reservoir 48 and the electrolyzer 50, alloys. A Suitable hydrogen Storage vessel of this type is described above. The components include a liquid water trap available from Harless Specialties.

86 to eliminate most of the entrained water from the hydro 35 Now referring to FIG. 4, a simplified cross-sectional view gen exiting the electrolyzer, a solenoid valve 88 to blow out of a catalytic converter monolith ShowS air and hydrogen the trap, a check valve 90, and a pressure relief valve 92 to flow in the axial direction through the monolith 30. The protect the System against over pressurization. FIG. 3 temperature of the monolith is measured with a thermo depicts additional details and a preferred arrangement of the couple at points 31 (a)-(e) along the central axis, with point hydrogen gas handling and capture System. 40 31 (a) being on the front face where the gases first contact As previously described, the electrolyzer 50 includes a the catalyst and the other points 31 (b)-(e) located at proton eXchange membrane in its construction So that gen positions successively further into the monolith. The results erated oxygen is vented to the water Source reservoir and the of these temperature measurements at 40 liters per minute hydrogen generated can be accumulated at pressure. Prior to (LPM) total gas flow rate containing 3%, 5%, 8.5% and 17% operation, the System of FIG.3 permits purging with an inert 45 hydrogen is shown in FIGS. 6(a)-(d). FIGS. 6(a)-(d) are gas, Such as nitrogen. For Safety reasons, all air is first graphs of the catalyst temperature measured at axial posi removed from the System by attaching a nitrogen gas tions within the monolith as indicated in FIG. 4. feedline at a purge gas inlet 94 downstream of a check valve Now referring to FIG. 5, a simplified cross-sectional view 90. During the purging operation, the hydrogen Storage of a catalytic converter monolith ShowS air and hydrogen cylinder or vessel 52, Such as a metal hydride vessel, is 50 flow in the radial direction through the monolith 30. The detached at a quick disconnect 96. This operation effectively temperature of the monolith is measured with a thermo seals both the vessel 52 and a gas line 98, to keep the purge couple at points 33(a)-(c) along the monolith radius, with gas out of the vessel 52. The remainder of the system is then point 33(c) being in the center of the monolith and the other purged from the purge gas inlet 94 through a back pressure points 31(b) and (a) located at greater distances from the regulator 100. 55 center. The results of these temperature measurements at 40 To charge the system with hydrogen, the needle valve 102 liters per minute (LPM) total gas flow rate containing 3%, between the Storage vessel 52 and the back pressure regu 5%, 8.5% and 17% hydrogen is shown in FIGS. 7(a)-(d). lator 100 is shut. Hydrogen gas generated by the electrolyzer FIGS. 7(a)-(d) are graphs of the catalyst temperature mea is processed through a four-stage process to remove Sured at radial positions within the monolith as indicated in entrained water (liquid or vapor) and any oxygen contami 60 FIG. 5.

nant from the hydrogen Stream before Storage. The first Step It has been found that the introduction of a relatively small involves removal of a Small amount of entrained liquid percentage of hydrogen in the air Stream of a typical water coming from the electrolyzer in the hydrogen gas. automobile gas exhaust provides nearly Spontaneous heating This entrained liquid water is removed without a pressure of a major portion of a face 32 (see FIG. 4) of the catalyst loss by means of the entrained liquid water trap 86. The 65 material almost immediately following ignition in the inter Second Step involves cooling the hydrogen gas Stream from nal combustion engine providing the exhaust gas. This the electrolyzer temperature to ambient in a condensing coil heating along the face 32 of the converter is fortuitous

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because it has been found that the most effective site for introduction of hydrogen to the engine ignition 124 and to providing local heating is along and near the upstream face coordinate hydrogen introduction during cold Start opera 32 of the catalyst monolith 30. In fact, where the monolith tions. The on-board hydrogen ignition assist System func 30 is made of a material that heats slowly when used in tions with or without the catalyst conditioning System but asSociation with the present invention, the face 32 may preferably included with Such a System Since they may both comprise a more reactive catalytic material to bring the use the hydrogen generation and on-board Storage. entire catalytic converter to light-off more quickly. In Another aspect of the invention provides oxygen recovery addition, the heat Supplied by the Spontaneous catalytic from the electrolyzer. Now referring to FIG. 9, a schematic combustion of the hydrogen in the presence of the catalytic diagram of a System having oxygen recovery and Storage converter 30 produces only a Small quantity of water as a equipment is shown providing for injection of oxygen into product of the reaction, which does not degrade the perfor the catalytic converter. The oxygen Separated from water in mance of the catalytic converter. the water reservoir 48, passes through the port 54 and is collected in a Storage vessel or cylinder 55. During ignition,

The air flow rate, depending on engine size and tuning and perhaps during all operation of the vehicle, the oxygen parameters, typically falls in the range of 40 to 250 liters per may be released from the vessel 55 by opening a valve 57

minute (LPM). The ideal range is between 80 and 200 Imp, and input into the air pump 44. In this manner, the oxygen depending on engine size. Effective concentrations of hydro enriches the air and provides more efficient catalytic com gen for these flow rates are one to twenty-eight volume bustion of the hydrogen or exhaust gases within the catalytic percent, with a preferred range of five to eighteen percent. converter 11.

The ideal range of hydrogen concentration, again depending Now referring to FIG. 10, a schematic diagram of a on engine Size, has been found to be eight to fifteen percent. System is shown having the air pump replaced with a venturi For example, at 150 LPM flow rate across the catalytic for drawing air into the catalytic converter. This aspect or converter, the ideal range of hydrogen concentration in that embodiment of the invention, eliminates the need for an air flow is 12 to 13 volume percent. Under those conditions, pump by drawing air into the hydrogen delivery line 46. light-off temperature at the face 32 is reached in about one second. At 90 LPM and at 8.5 to 11 volume percent 25 to Referring back to FIG. 1, a power source 132 is coupled the hydrogen Solenoid valve 138 upon engaging the hydrogen, light-off is achieved in about two Seconds. ignition Switch 134. In one preferred method of operation, The power consumption of the catalyst varies depending the Solenoid valve 138 may remain open or be pulsed until on the flow rate and the concentration of hydrogen. For the thermocouple 136 reads a temperature equal to or greater example, at a flow rate of 30 to 50 LPM and a concentration than the light-off temperature.

of 10–11 % Volume percent hydrogen, the power required to heat the monolith to light-off is approximately 1.5 Watt theAlso in FIG. 1, the electrolyzer 50 receives power from Source 132 when the hydrogen pressure in or near the hours. Similar results in the electrically heated catalyst hydrogen storage vessel 52, as indicated by pressure Sensor (EHC) unit require approximately 10 to 15 Watt hours. 133, falls below a setpoint pressure between about 100 psig The present invention is also suitable for use in low 35 and about 400 psig. It should be recognized that the power ambient temperature conditions, as low as -7°C. or lower. to the electrolyzer 50 is turned off when the pressure exceeds Depending on the active catalyst compositions used, the a high pressure Setpoint, Such as 400 psig. It should also be amount of time required to achieve light-off may double. In recognized that many other conditions may be considered in those conditions, it may be desirable to add a Small electrical controlling the electrolyzer.

heater, which would be much smaller than an EHC heater 40 Now referring to FIG. 11, a control diagram illustrates a and require only about 200 Watts of power, in order to catalytic converter system 140, similar to that of FIG. 1, achieve the results at normal ambient temperatures. using a microprocessor controller 142 to monitor and control Now referring to FIG. 8, one aspect of the invention various functions of the System. For example, the tempera provides an on-board hydrogen ignition assist System. A ture of the catalytic converter 11 as measured by the ther Source of hydrogen, Such as the electrolyzer described above 45 mocouple 136 is communicated to the microprocessor con or any Suitable means, fills the hydrogen Storage cylinder 52. troller 142. The controller 142 may then send a signal to the An ignition Supply line to a control valve 122 controls the hydrogen release valve 138 to close when the temperature Supply of hydrogen into an engine ignition 124. The engine exceeds a light-off temperature. Furthermore, power to the ignition 124 includes the fuel, air, and electrical components electrolyzer 50 may be supplied under various conditions for an internal combustion engine 126. Thus, the hydrogen 50 Such as when the pressure Sensor 133 indicates a low can be Supplied at any convenient location So that it is preSSure in the Storage tank 52. Other various control injected into the cylinders of the engine 126. For example, Schemes and considerations may be employed as will be hydrogen under pressure can be Supplied to the intake readily recognized by those with skill in the art which are manifold where there is already a fuel/air mixture (during within the Scope of the present invention. For example, the the inlet cycle), or the hydrogen can be mixed with air before 55 microprocessor may also be programmed to carry out timed it goes to the engines fuel injection System, or other means. control functions apart from responding to Sensory inputs, The system of FIG. 8 turns the internal combustion engine and may also serve various Safety functions. 126 into a hydrogen fuel injected engine for the first few Now referring to FIGS. 12(a) and (b), graphs are provided Seconds of Start-up, before any gasoline is introduced into showing the catalyst temperature at various axial distances the engine. This way, the catalytic converter can be brought 60 and radial distances in the catalyst monolith over a period of to light-off temperature before the engine begins producing 50 Seconds using a pulsed release of hydrogen into an air undesirable emissions. Then, when gasoline is finally Stream. The graphs show the temperature rise in the catalytic injected into the System, the catalytic converter is heated to converter monolith at an air flow rate of 90 LPM and pulsed an efficient operating temperature. hydrogen flow controlled by a microprocessor. The pulsed Expended fuel gases are collected in an output manifold 65 hydrogen flow was provided by opening the hydrogen 128 and flow into the exhaust line 42. An ignition control release valve 138 (see FIG. 1) for 0.01 seconds and closing 130 provides control signals to the control valve 122 for the the valve for 0.66 seconds, successively 10 times.

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Comparing the temperature profiles of FIG. 12(a) with injection tubes 192 delivering hydrogen into the gaps 195. those of FIGS. 6(a)-(d) and the temperature profile of FIG. Conversely, in FIG. 17(b) the manifold is in the center of the 12(b) with those of FIGS. 7(a)-(d) it is shown that light-off monoliths 194 with a plurality of holes for hydrogen deliv temperatures of between about 400° C. and about 600 C. ery into the gaps 195.

can be readily attained even with pulsed hydrogen flow. One Now referring to FIG. 18, a schematic diagram of a advantage of pulsed flow is the conservation of the hydrogen catalytic converter 11 is shown having an upstream isolation Supply. valve 212 and a downstream isolation valve 202. When the Now referring to FIG. 13, a graph of the pressure in the Valves 212, 202 are closed, hydrogen can be injected into the hydrogen Storage tank after Successive pulsed hydrogen monolith 30 and allowed to diffuse evenly throughout the releases with valve open times of 0.01 seconds and valve monolith. After only a fraction of second for diffusion, the closed time of 0.66 seconds. Over a period of 40 pulses, the Valve 202 is opened and oxygen is delivered to provide a 12 liter hydrogen Storage vessel is depleted to about 3 liters combination mixture. Alternately, because oxygen is a larger with a decrease in pressure from about 350 psig to about 100 molecule tageous to and diffuses more Slowly, it may also be advan diffuse oxygen into the isolated monolith, then pSig. 15 introduce hydrogen while opening valve 202. In cold weather, a passenger cabin often takes an uncom Now referring to FIG. 19(a)-(d) which are schematic fortably long time to heat up from the vehicle's heating diagrams outlining four possible topologies for the powering System. FIG. 14 is a Schematic diagram of a heat eXchanger of the electrolyzer system 200. In FIG. 19(a) the primary 150 having a catalyst 152 formed on one surface receiving Source of electrolyzer power is drawn directly from the hydrogen and oxygen and another Surface Suitable for the vehicle battery 201 as well as from the alternator 203. FIG. passage of air for cabin circulation. The heat eXchanger may 19(b) eliminates the electrical draw on the battery 201 by be of any type or Style, Such as a shell and tube heat placing diode 202 between the alternator 203 and the battery exchanger having cabin air flow on the shell side 154 and the 201. Diode 202 allows current flow from the alternator to the hydrogen/oxygen mixture on the tube side 156. The catalyst 152 is preferably formed on the internal surface of the tubes 25 battery and other vehicle loads 205 but stops current flow 158. It is also preferred that the heat exchanger be incorpo from the battery to the electrolyzer 200. The current limiting rated into or compatible with existing air circulation Systems circuit 206 protects the electrical system from over currents in a vehicle. A preferred configuration of the cabin heater is that could be drawn by the electrolyzer as the electrolyzer shown in FIG. 20 wherein the cabin air flow 154 passes resistance changes. FIG. 19(c) is shown having an alternator through a freon loop 153, a radiator hot water loop 155, and 204 having an additional winding in which the magnetic the external Surface of a heat eXchanger 150 having an circuit provides current limiting to the electrolyzer 200. This internal Surface coated with a noble metal catalyst. Second winding would also allow higher Voltages to be Now referring to FIG. 15, a schematic diagram of a delivered to the electrolyzer 200, allowing the number of catalytic combination gas heater 160 for a diesel engine 162 cells within the stack to be increased. FIG. 19(d) shows a is shown. The catalytic combination gas heater 160 is filled 35 System in which the vehicle alternating current is drawn or lined with a Suitable catalyst for combination of hydrogen from the alternator 207 before the vehicle regulator 209 and and oxygen to heat ambient air entering from the intake 164. a separate current control/regulator 208 provides electrical Hydrogen from Supply line 166, and preferably oxygen from power to the electrolyzer 200. This topology is able to supply line 168, are delivered to the catalytic heater 160 current limit the electrolyzer load and provide higher Volt before entering the combustion chamber 170 of the diesel 40 ages to the electrolyzer while using a conventional alterna engine 162. In operation, the diesel injector 172 provides tor.

atomized diesel fuel to the chamber 170. Without the cata The apparatus of the present invention, described above, lytic heater 160, the ambient temperature of the air passing may be operated in any number of ways as will be recog into the chamber 170 through the air intake valve 174 may 45 nized

by those in the art. One preferred mode of operating

System of the present invention, including an electrolyzer, not be sufficiently warm to prevent condensation of the fuel is described on the chamber walls. However, the catalytic heater 160 is chemically inheated FIG. 20. The modes of operation for an ideal catalyst (“CHC”) a trademark of capable of heating the air Sufficiently So that the fuel does Lynntech, Inc., College Station, Texas, are: 1.) Pre-Start, not condense and the engine may be more readily Started. which includes: Safety monitoring, System Status, and sleep; Now referring to FIG. 16, a schematic diagram of an 50 2.) Start, which includes: System status, and converter tem electrolyzer 180 is shown having dummy cells 182 for perature; 3.) Pre-Heat which includes: start air pump, release heating or cooling the electrolyzer using liquid from a H2 until a certain time, temperature, Volume (pressure); vehicle radiator 184. The dummy cells 182 may be com Safety monitoring, and System status; 4.) Rest which prised of plates providing a passage for the radiator fluid includes: Safety monitoring and System status; 5.) Restore between electrolytic cells 184 in order to absorb or deliver 55 H. Supply, which includes: electrolyze, control current heat to the electrolyzer. Because electrolyZerS operate most draw, Safety monitoring, System status, and monitor the efficiently at elevated temperatures, the radiator may be used pressure and temperature; 6.) System Maintenance, which to warm the electrolyzer in cold weather conditions. includes: recover cathode water, System status, and Safety Alternately, the radiator fluid may be used to cool the 60 monitoring; and 7.) Return to Pre-Start the modes of opera electrolyzer after an extended period of use. tion for an ideal chemically heated catalyst (CHC, a trade Now referring to FIGS. 17(a) and (b), two catalytic mark of Lynntech, Inc. of College Station, Tex.) System. converters 11 are shown having hydrogen injection mani While the foregoing is directed to the preferred embodi folds 190. In each of the figures, the converters 11 have ment of the present invention, other and further embodi multiple monoliths 194 separated by a short distance for 65 ments of the invention may be devised without departing hydrogen introduction and diffusion. In FIG. 17(a), the from the basic scope thereof. The scope of the invention is manifold is external to the converter 11 with a plurality of determined by the claims which follow.

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What is claimed is: an on-board electrolyzer for producing hydrogen, wherein 1. A catalytic converter in the exhaust line of an internal the electrolyzer is in fluid communication with a hydro combustion engine, comprising: gen Storage Vessel;

a canister; a pressure Sensor disposed in communication with the a plurality of catalytic monoliths within the canister; hydrogen Storage vessel;

a Source of hydrogen; a passage for communicating hydrogen from the hydro a gap between each of the plurality of monoliths, and gen Storage vessel to the catalyst wherein the passage means for introducing hydrogen from the Source of hydro is free of an ignition Source; gen into the canister upstream of the plurality of 1O a flow control member disposed in the passage for controlling the delivery of hydrogen into the catalyst;

monoliths and into the gap between each of the plu a controller for adjusting the flow control member to rality of monoliths. increase the catalyst temperature as indicated by the 2. The catalytic converter of claim 1 wherein the means temperature Sensor to a light-off temperature and for introducing hydrogen comprises a manifold within the adjusting the power to the electrolyzer when the canister. 15 preSSure Sensor indicates a setpoint pressure.

3. The catalytic converter of claim 1 wherein the means 7. The apparatus of claim 6 wherein the power source is for introducing hydrogen comprises a manifold outside the coupled to a battery and an automotive alternator. canister.

8. The apparatus of claim 7 further comprising:

4. A catalytic converter System for the exhaust of an internal combustion engine with an exhaust line, compris (a) a diode placed in electronic communication between ing: the battery and the alternator to prevent the flow of current from the battery to the electrolyzer; and a catalytic converter in the exhaust line; (b) a current limiting circuit in electronic communication a Source of hydrogen; between the power Source and the electrolyzer to a conduit connecting the Source of hydrogen to the 25 protect the battery and electrolyzer from over currents. exhaust line upstream of the catalytic converter; 9. The apparatus of claim 8 wherein the current limiting a Source of oxygen; circuit comprises a magnetic circuit built into the alternator. means for controlling the introduction of hydrogen from 10. The apparatus of claim 7 further comprising a current the Source of hydrogen to the exhaust line; control regulator Separate from any vehicle regulator. means for controlling the introduction of oxygen from the exhaust 11. A method for controlling cold start emissions from the Source of oxygen to the exhaust line, independent of the of : System of a combustion engine comprising the Steps means for controlling the introduction of hydrogen;

an isolation valve in the exhaust line upstream of the (a) starting the engine;

catalytic converter; and (b) measuring an initial temperature of a catalyst in the an isolation valve in the exhaust line downstream of the 35 exhaust System;

catalytic converter. (c) producing hydrogen and oxygen with an electrolyzer 5. An apparatus comprising: on board the vehicle;

a catalyst in the exhaust System of an internal combustion (d) storing the produced hydrogen in a first vessel and the engine; 40

Oxygen in a Second vessel;

a temperature Sensor in thermal communication with the (e) delivering Stored hydrogen to the catalyst; catalyst; (f) delivering Stored oxygen to the catalyst; and an on-board electrolyzer for producing hydrogen and (g) heating the catalyst by exothermic catalytic combina oxygen, wherein the electrolyzer is in communication tion of hydrogen and oxygen from the initial tempera with a hydrogen Storage vessel and an oxygen Storage 45 ture up to a light-off temperature. vessel; 12. The method of claim 11 wherein hydrogen is released a pressure Sensor disposed in communication with the released. and allowed to diffuse in the catalyst before oxygen is hydrogen Storage vessel; 13. The method of claim 11 wherein the oxygen is a passage for communicating hydrogen from the hydro 50 released and allowed to diffuse in the catalyst before hydro gen Storage vessel to the catalyst, wherein the passage gen is released.

is free of an ignition Source; 14. A method comprising the Steps of a passage for communicating oxygen from the oxygen (a) starting the engine;

Storage vessel to the catalyst; (b) measuring an initial temperature of a catalyst in the a flow control member disposed in the passage for 55 exhaust System;

controlling the delivery of hydrogen into the catalyst;

and (c) producing hydrogen and oxygen with an electrolyzer a controller for adjusting the flow control member to on board the vehicle;

increase the catalyst temperature as indicated by the (d) Storing the produced hydrogen in a vessel; temperature Sensor to a light-off temperature and 60 (e) delivering Stored hydrogen to the catalyst; adjusting the power to the electrolyzer when the (f) providing a Source of oxygen to the catalyst; preSSure Sensor indicates a setpoint pressure. (g) heating the catalyst by exothermic catalytic combina 6. An apparatus comprising: tion of hydrogen and oxygen from the initial tempera a catalyst in the exhaust System of an internal combustion ture up to a light-off temperature, and engine; 65 (h) monitoring the pressure in the hydrogen Storage a temperature Sensor in thermal communication with the cylinder and controlling the electrolyzer based on the catalyst; preSSure.

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15. The method of claim 14 wherein pressure monitoring 17. A method for controlling cold start emissions from the and electrolyzer operation are controlled by a controller on exhaust System of a combustion engine comprising the Steps board the vehicle. of:

16. A method for controlling cold start emissions from the (a) starting the engine;

exhaust System of a combustion engine comprising the Steps of: (b) measuring an initial temperature of a catalyst in the (a) starting the engine; exhaust System;

(b) measuring an initial temperature of a catalyst in the (c) producing hydrogen on board the vehicle;

(d) Storing the produced hydrogen in a vessel (c) producing hydrogen on board the vehicle; (e) delivering Stored hydrogen to the catalyst; (d) Storing the produced hydrogen in a vessel (f) heating the catalyst by exothermic catalytic combina (e) delivering Stored hydrogen to the catalyst; tion of hydrogen and oxygen from the initial tempera (f) heating the catalyst by exothermic catalytic combina ture up to a light-off temperature, and tion of hydrogen and oxygen from the initial tempera 15 (g) providing air into the catalyst, wherein the air is ture up to a light-off temperature, and allowed to diffuse in the catalyst before hydrogen is (g) providing air into the catalyst, wherein the hydrogen delivered to the catalyst. is allowed to diffuse in the catalyst before air is provided. k k k k k