March 31, 2016 - 5:31 PM EDT
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"Systems and Methods for Reducing Emissions in Exhaust of Vehicles and Producing Electricity" in Patent Application Approval Process (USPTO...

"Systems and Methods for Reducing Emissions in Exhaust of Vehicles and Producing Electricity" in Patent Application Approval Process (USPTO 20160076419)

By a News Reporter-Staff News Editor at Life Science Weekly -- A patent application by the inventor Roy, Jean (

Waltham, MA
), filed on November 20, 2015, was made available online on March 24, 2016, according to news reporting originating from
Washington, D.C.
, by NewsRx correspondents (see also Patents).

This patent application has not been assigned to a company or institution.

The following quote was obtained by the news editors from the background information supplied by the inventors: "Spark ignited (SI) internal combustion (IC) engines produce small amounts of undesirable chemical compounds in the combustion chamber, compounds which are exhausted from the engine at high temperatures (800.degree.-1250.degree. F.). For fuels composed primarily of methane and other light hydrocarbons, the commonly regulated chemicals are nitrogen oxides (NO, NO.sub.2, or generally NO.sub.x) and carbon monoxide (CO). Nitrogen oxides are formed when nitrogen (N.sub.2), a major component of air, reacts with oxygen (O.sub.2), another component of air, and both are exposed to high temperatures and pressures in an engine combustion chamber. Carbon monoxide, on the other hand, is the consequence of failure of the fuel to completely react with oxygen, resulting in the formation of carbon dioxide (CO.sub.2). CO and NO.sub.x are problematic pollutants inasmuch as their regulated values are in many geographical regions set at or below the limits of current technology.

"In strictly regulated regions, current practice to control the emission from SI/IC engines fueled by methane-rich fuels (natural gas, bio-fuels, landfill gas, etc.), is to install systems in the engine exhaust ducting to eliminate, to the extent required by regulations, such chemicals. For smaller engines (less than 1000 bhp), the common aftertreatment system is a single stage catalyst. In small systems, the products of combustion exiting the engine are forced through a catalyst monolith (honeycomb structure with precious metal coating) which facilitates the desirable oxidation and reduction reactions:

"NO.sub.x yields N.sub.2+O.sub.2

"CO+O.sub.2 yields CO.sub.2

"The nitrogen oxides are reduced to gaseous nitrogen (N.sub.2) and oxygen (O.sub.2), both benign, while the carbon monoxide (CO) is completely oxidized, forming carbon dioxide (CO.sub.2), likewise non-harmful and unregulated.

"Current catalyst-based emissions systems rely on very accurate control of the engine's operating parameters to maximize the conversion efficiency of the reactions noted above. Specifically, the simultaneous elimination of NO.sub.x and CO through such reactions in a catalytic converter requires a precise operating window of the engine combustion process relative to the mixture of air and fuel. This is depicted in FIG. 1 for a typical SI/IC engine. As shown, rich mixtures result in low NO.sub.x out of the catalyst, but high CO, while lean mixtures result in low CO, but high NO.sub.x. From FIG. 1, it is evident that simultaneous cleanup of NO.sub.x and CO requires that the engine air/fuel ratio (AFR) be precisely controlled in the narrow region around the stoichiometric air/fuel ratio (i.e., the theoretical air-fuel ratio required for complete combustion of fuel without any unreacted oxygen). Compliance of both regulated pollutants can only be maintained when the combustion stoichiometry is maintained within points A and B of FIG. 1. The acceptable combustion mixture, to achieve increasingly strict emissions standards, requires that the engine AFR be controlled within narrow limits.

"Referring still to FIG. 1, there is depicted typical engine emissions as a function of AFR from a SI/IC engine equipped with a single or multiple three-way catalyst (TWC). Meeting the regulated limits for CO and NO.sub.x require that engine AFR be maintained between points A and B of FIG. 1, a band approximately representing the stoichiometric AFR.

"Stationary SI/IC engines operating in most applications in the

U.S.
and elsewhere are highly regulated relative to allowable CO and NO.sub.x emissions, which are becoming increasingly controlled. Most notably, the California Air Resource Board (CARB) now recommends limits of 0.07 lb/MWh and 0.1 lb/MWh CO as part of their 2007 standard for Combined Heat and Power (CHP) applications. Applying a heat recovery credit for maintaining a minimum 60% overall system efficiency and assuming a 27% electrical efficiency, the emissions limits stated in terms of actual concentration in the exhaust gas are 3.7 PPM NO.sub.x and 8.9 PPM CO. As used herein, 'PPM' means parts per million by volume corrected to a standard air dilution factor (15% oxygen equivalent). The area of
Southern California
under the jurisdiction of the South Coast Air Quality Management District (SCAQMD) has adopted the 'CARB 2007' standard for NO.sub.x, while restricting CO emissions to a value close to the CARB limit. Other regions in
California
are likewise adopting similar standards, while other regions of the country (
U.S.
) are phasing in regulations approaching the CARB 2007 standards (MA, NY and NJ, for example).

"Compliance with the newer standards requires extremely high conversion efficiency in the catalyst for both CO and NO.sub.x. Extra-large conversion monoliths are needed in addition to extreme precision in controlling the air/fuel mixture.

"Similar challenges exist for SI/IC engines in vehicles. The Environmental Protection Agency and CARB have adopted standards that limit the emissions of NOx, CO, and NMOG (Non-methane Organic Gas).

"FIG. 2 depicts the steady-state AFR control precision required for a standard engine (Model TecoDrive 7400) utilizing a TWC system sized to conform to CARB 2007. As indicated by a pre-catalyst narrow-band heated exhaust gas oxygen sensor millivolt (mV) output the AFR controller maintains via steady-state (non-dithering) AFR control. As shown in FIG. 2, the engine combustion mixture (air to fuel ratio) is acceptable for catalyst performance to regulated limits only when the signal from a standard lambda sensor in the exhaust duct is maintained between 680 and 694 mV. Above this range, the CO concentration exiting the catalyst exceeds the SCAQMD limit of 8.9 PPM. While below this range the NO.sub.x will rapidly exceed the 3.7 PPM limit. Limits shown in FIG. 2 are those of CARB 2007 with a credit for engine heat recovery, such that 60% of the fuel's heat content is purposefully used as electric power or recovered thermal energy. In order to maintain compliance, combustion air to fuel mixture must be maintained within the 14 mV window for the example shown.

"A possible method for expanding the control window for engine operation to attain acceptable emissions from both CO and NO.sub.x, is to modify the system such that two stages of catalyst systems are used, each operating in distinctly different chemical atmospheres. Early catalyst systems commonly used a two-stage design with inter-stage air injection. In this era, single purpose catalyst monoliths-oxidation or reduction, but not both, were employed. Later as multi-purpose, single stage catalysts (TWC) were developed, these became the dominant style. The early two-stage systems were employed in stationary gaseous fueled SI/IC engines with success but under far less strict standards. Presumably, the NO reformation problems encountered with the two-stage systems were present in the earlier era, but were inconsequential relative to the regulated limits at that time.

"FIG. 3 depicts the above-described arrangement. As shown, two catalyst stages are plumbed into an exhaust system in series. Air is pumped into the exhaust stream between a stage one catalyst (CAT 1) (a reduction catalyst) and a stage 2 catalyst (CAT 2) (an oxidation catalyst) and mixed thoroughly. The engine air-to-fuel ratio is maintained so as to facilitate effective NO.sub.x removal in the first stage. The air injected into the exhaust results in an oxidizing environment at the second catalyst stage biased towards the oxidation of CO to CO.sub.2, even if the engine AFR is outside the acceptable operation window on the rich side, a highly significant benefit.

"Tests utilizing the two-stage system demonstrated that the two-stage strategy with air injection was not only ineffective, but actually detrimental to catalyst performance. NO.sub.x emissions from the two-stage system were found to be generally higher than a single-stage system of comparable size and catalyst material loading. This surprising result indicated that a mechanism exists such that NO.sub.x is formed in the second stage, made possible by the oxygen rich environment, coupled also with conditions conducive to chemical reaction, i.e., high temperature and an abundance of a catalytic material.

"It would be desirable to consistently and reliably removing nitrogen oxides and carbon monoxide, as well as hydrocarbons, hydrogen gas and/or organic compounds, from the exhausts of spark-ignited internal combustion engines.

"It would also be desirable to improve the efficiency of spark-ignited internal combustion engines and vehicles containing such engines."

In addition to the background information obtained for this patent application, NewsRx journalists also obtained the inventor's summary information for this patent application: "With the above and other objects in view, a feature of the invention is the provision of assemblies and methods for effectively reducing nitrogen oxides, carbon monoxide, hydrocarbons, organic compounds and/or hydrogen gas in spark-ignited internal combustion engine exhausts, by presenting the gases entering a catalytic converter second stage at a lower temperature.

"In accordance with the invention, the gases entering the second catalytic converter stage are cooled immediately following stage one, from the extremely high temperatures normally exiting the engine (800.degree.-1250.degree. F.) to a lower value. An intermediate temperature, or range of temperatures, provide desirable chemical reactions (CO and hydrocarbon removal) and are highly favored over those that are undesirable because of NO.sub.2 formation. This is deemed to be a particularly viable approach in combining heat and power (CHP) applications, inasmuch as the gases are cooled in a heat reclaim process. Doing so in a CHP application requires only that (1) the cooling stage be oriented to cool between stages, and (2) the cooling effectiveness be altered to reside in a favorable temperature range. This approach can also be applied to exhaust systems for vehicles.

"In accordance with a further feature of the invention, the cooling of the gases entering the second catalytic converter stage is undertaken in whole or in part by a thermoelectric generator (TEG) which functions to generate useful electricity while cooling exhaust gases. The electricity generated by a TEG in a CHP application can be used to power a building, a portion of a building, or an auxiliary system for the building (e.g., an air conditioner). Likewise, the electricity generated by a TEG in a vehicular application can be used to power (or complement the power generated by the alternator) the sound system, the climate control system (e.g., air conditioner and fan), the defroster, power seats, and other electrical components in a vehicle. The electricity can also be used to propel the vehicle, for example by powering or partially powering an electric motor.

"The above and other features of the invention, including various novel details of construction and combinations of parts and method steps, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular assemblies and methods embodying the invention are shown by way of illustration only and not as limitations of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

"Reference is made to the accompanying drawings in which are shown illustrative embodiments of the invention, from which its novel features and advantages will be apparent. In the drawings:

"FIG. 1 is a chart depicting prior art relationships between nitrogen oxides and carbon monoxide present in engine exhausts gases, within and beyond acceptable ranges, given a precisely controlled air/fuel ratio;

"FIG. 2 is a chart illustrating the prior art steady-state air/fuel ratio control required for a standard engine, using a three-way catalyst;

"FIG. 3 is a diagrammatic depiction of a prior art two-stage catalyst system with inter-stage oxidizing air injection;

"FIG. 4 is a diagrammatic depiction of an assembly and method for reducing nitrogen oxides, carbon monoxide, hydrocarbons and/or hydrogen gas in the exhaust of an internal combustion engine, and for simultaneously generating electrical energy;

"FIG. 5 is a flowchart for a method for reducing nitrogen oxides, carbon monoxide, hydrocarbons, organic compounds, and/or hydrogen gas from exhausts of internal combustion engines and for generating electrical energy;

"FIG. 6 is a diagrammatic depiction of an alternative assembly and method for reducing nitrogen oxides, carbon monoxide, organic compounds, and/or hydrogen gas in the exhaust of an internal combustion engine and for providing an output of electrical energy;

"FIG. 7 is an apparatus having a two-stage system with inter-stage cooling according to an embodiment, which was used to perform testing;

"FIG. 8 is a chart illustrating the results of a Test 1 described hereinbelow;

"FIG. 9 is a chart similar to FIG. 8, but illustrating markedly different and greater improved reductions of nitrogen oxides and carbon monoxide;

"FIG. 10 is a chart showing that even with maladjustment of an air-to-fuel ratio controller, the inventive assemblies and methods provide for lower emissions and greater tolerance for excursions in engine air-to-fuel ratios;

"FIG. 11 is an apparatus having a two-stage system with inter-stage cooling according to an embodiment;

"FIG. 12 is an apparatus having a two-stage system with inter-stage cooling according to an embodiment;

"FIG. 13 is an apparatus having a two-stage system with inter-stage cooling according to an embodiment; and

"FIG. 14 is a block diagram of an underside of a vehicle that includes an exhaust and emissions system according to an embodiment."

URL and more information on this patent application, see: Roy, Jean. Systems and Methods for Reducing Emissions in Exhaust of Vehicles and Producing Electricity. Filed November 20, 2015 and posted March 24, 2016. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=4835&p=97&f=G&l=50&d=PG01&S1=20160317.PD.&OS=PD/20160317&RS=PD/20160317

Keywords for this news article include: Gases, Anions, Patents, Elements, Hydrogen, Chemistry, Chalcogens, Hydrocarbons, Carbon Dioxide, Carbon Monoxide, Nitrogen Oxides, Oxygen Compounds, Nitrogen Compounds, Inorganic Chemicals, Inorganic Carbon Compounds.

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Source: Equities.com News (March 31, 2016 - 5:31 PM EDT)

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