Showing papers on "Secondary air injection published in 1996"

Pressure control system for semiconductor manufacturing equipment

Abstract: A vacuum process system for semiconductor manufacturing equipment provided with a vacuum chamber for processing semiconductor wafers under a prescribed vacuum pressure, wherein the vacuum process system is provided with an exhaust pipe connected to the vacuum chamber. A pressure control valve and exhaust control valve are provided in series with the exhaust closing valve provided on the exhaust pipe. The interior of the vacuum chamber is exhausted using the exhaust pump and the pressure control valve and exhaust control valve are controlled by the process controller. Thereby, the rising time and exhaust time are both shortened while supplying gas.

Air handling unit including control system that prevents outside air from entering the unit through an exhaust air damper

Abstract: A control system for controlling an air handling unit. The control system links the position of an exhaust air damper and a recirculation air damper so as the exhaust air damper is opened, the recirculation air damper is closed the same amount, and vice versa. An outside air damper remains completely open at all times. The relative positions of the exhaust air damper and the recirculation air damper control the amount of outside air that is emitted into the air handling unit through the outside air damper. For each of the control states of heating with minimum outside air, cooling with outside air, mechanical cooling with maximum outside air, and mechanical cooling with minimum outside air, the outside air damper remains completely open, and the position of the exhaust air damper and the recirculation air damper are controlled based on a particular state. Sequencing strategies are employed for transitions between the control states that utilize these positions of the dampers.

Method and apparatus for providing diluent gas to exhaust emission analyzer

Abstract: An apparatus (10) for diluting exhaust gas emissions by using a small fraction of a continuously extracted exhaust sample (12) combined with a pollutant-free diluent (36) through a system of devices such as critical flow orifices (22, 48) at a predetermined and precisely controlled flow ratio. A small quantity of gas is extracted from the diluted exhaust gas available with the purified air or nitrogen to produce a mixture having a dew point below ambient air temperature and satisfying the flow requirements of an analysis system.

A method for purifying combustion exhaust gas

Abstract: The method for purifying combustion exhaust gas according to the present invention utilizes a NH3 decomposing catalyst. The NH3 decomposing catalyst in the present invention is capable of converting substantially all of the NH3 in the combustion exhaust gas to N2 when the air-fuel ratio of the exhaust gas is lean and the temperature of the catalyst is within a predetermined optimum temperature range. Further, when the exhaust gas contains NOx in addition to NH3, the NH3 decomposing catalyst is capable of reducing the NOx in the optimum temperature range even though the air-fuel ratio of the exhaust gas is lean. In the present invention, the conditions of the exhaust gas containing NOx are adjusted before it is fed to the NH3 decomposing catalyst in such a manner that the temperature of the exhaust gas is within the optimum temperature range and the air-fuel ratio of the exhaust gas is lean. Further, NH3 is added to the exhaust gas before it is fed to the NH3 decomposing catalyst. Therefore, a lean air-fuel ratio exhaust gas, at a temperature within the optimum temperature range, which contains both the NOx and NH3 is fed to the NH3 decomposing catalyst, and the NOx, as well as the NH3, in the exhaust gas is completely resolved by the NH3 decomposing catalyst.

Multiphase numerical simulation of air sparging performance

Abstract: The performance of air sparging systems, as measured by the predicted region of airflow, was investigated by conducting numerical simulations with a multiphase modeling program (TETRAD). The simulations employed standard two-phase flow theory, and included pressure-dependent calculations of the compressibility of water and air. Simulations tested the response of air sparging systems to variations in geological properties. Three stages of flow behavior are predicted following initiation of air injection. These are: (1) an initial transient period of growth in the lateral and vertical limits of airflow (expansion stage); (2) a second transient period of reduction in the lateral limits of airflow (collapse stage); and (3) a steady-state stage, during which the system remains static as long as injection parameters do not change. In homogeneous media the geometry of the region of airflow changes from a teardrop- or bell-shaped configuration to a shape that is roughly conical during the expansion stage. During the collapse stage, air is preferentially diverted to established regions of high effective air permeability, and ground water resaturates the remainder of the original region of influence. For pilot testing it is important to realize that measurements of the lateral extent of airflow expansion and collapse stages can bemore » misleading because they will differ from the limits established at steady-state. The time required for a particular system to progress through the transient stages and establish steady-state behavior can vary from hours to years, and is dependent on the permeability structure of the aquifer, injection depth, and injection rate. Under homogeneous conditions the maximum width of the region of airflow attained during the transient expansion stage was substantially greater than the width attached at steady-state.« less

Effects of Process Control Changes on Aquifer Oxygenation Rates During In Situ Air Sparging in Homogeneous Aquifers

Abstract: In situ air sparging is used to remediate petroleum fuels and chlorinated solvents present as submerged contaminant source /ones and dissolved contaminant plumes, or to provide barriers to dissolved contaminant plume migration. Contaminant removal occurs through a combination of volatilization and aerobic biodegradation: thus, the performance at any given site depends on the contaminant and oxygen mass transfer rates induced by the air injection. It has been hypothesized that these rates are sensitive to changes in process flow conditions and site lithology, but no data is available to identify trends or the magnitude of the changes. In this work, oxygenation rates were measured for a range of air injection rates, ground water flow rates, and pulsing frequencies using a laboratory-scale two-dimensional physical model constructed to simulate a homogeneous hydrogeologic setting. Experiments were conducted with water having low chemical and biochemical oxygen demand. Results suggest the following: that there is an optimum air injection rate: advective How of ground water can be a significant factor when ground water velocities are > 0.3 m/d: and pulsing the air injection had little effect on the oxygenation rate relative lo the continuous air injection case.

Method and apparatus for treatment of exhaust streams

Abstract: In a system for treating an exhaust stream, such as the exhaust of an internal combustion engine (10), the exhaust is initially treated by a first catalytic converter (14) and its effluent is cooled in an indirect heat exchanger (18) with an extraneous coolant fluid, i.e., one other than recycled engine exhaust, before introducing the exhaust into a hydrocarbon trap (30) to adsorb hydrocarbons therefrom at least during a cold-start period of engine operation. Such cooling enables utilization of highly efficient adsorbent materials such as activated carbon which otherwise could not be used. Adsorbed hydrocarbons are desorbed from the hydrocarbon trap (30) as the engine exhaust heats up. The exhaust is passed from hydrocarbon trap (30) to a second catalytic converter (34) for oxidation of the hydrocarbons. The coolant fluid may be air and the heated air obtained from the heat exchanger (18) may be introduced into the oxidation catalytic converter (34) to heat the latter at least during cold-start operation and to supply additional oxygen.

Internal combustion engine with exhaust gas recirculation

Abstract: In an internal combustion engine with exhaust gas recirculation wherein the engine has a charge air intake pipe for supplying combustion air to the engine, an exhaust pipe for discharging exhaust gas from the engine and an exhaust gas recirculation line extending between an exhaust gas recirculation valve arranged in the exhaust pipe and the charge air intake pipe for the controllable return of exhaust gas to the charge air intake pipe, a heat exchanger is disposed in the exhaust gas recirculation line and means are provided for supplying air under pressure to the heat exchanger for cleaning the heat exchanger.

Failure detection system of exhaust secondary air supply system of internal combustion engine

Abstract: A system and method for detecting a failure occurring in an exhaust secondary air supply system of an internal combustion engine. A conduit is connected to the exhaust pipe to supply secondary air to the exhaust pipe to promote oxidization of the emissions in the exhaust gases. A valve is provided in the conduit for opening/closing it. The failure of the valve is detected by operating the air pump to supply the air in the conduit, while closing the conduit by the valve. The air/fuel ratio is detected by an oxygen sensor installed downstream of the conduit to be compared with a desired air/fuel ratio. If the detected air/fuel ratio is leaner than a desired air/fuel ratio, the air flows to the exhaust pipe so that the valve is considered to be stuck to open. Alternatively, a pump current is detected and is compared with a reference value indicative of the current at no air flow. If the detected current is less than the reference value, the valve is considered to be in failure. Moreover, the movement of a valve member is sensed to detect whether the valve is stuck to close.

Closely coupled exhaust catalyst system and engine strategy associated therewith

Abstract: A catalytic converter having a first highly loaded palladium or trimetal catalytic element containing palladium of relatively large particle size closely coupled to the engine exhaust manifold, followed by one or more second catalytic elements having high oxygen storage capacity to provide protection against warmed-up engine emissions break through, is efficient in reducing cold-start emissions through early catalyst light-off. The catalytic converter is advantageously used in conjunction with an engine strategy employing oscillative spark retard during warm up to further reduce catalyst light-off and transient spark advance dampening to eliminate spiking of HC and CO during engine transients. When employed in conjunction with secondary air injection, the engine EEC is programmed to delay air injection for a period following cold-start sufficient to assure that catalyst light-off is rapidly attained.

Exhaust Hood Apparatus

Abstract: An exhaust hood apparatus, adapted to be mounted over a cooking station for expelling air containing cooking by-products, is described herein. The exhaust hood apparatus includes a controller circuit electrically connected to at least a temperature sensor, an exhaust fan and a plenum chamber washing system. The controller circuit is configured so as to energize the exhaust fan and the washing system if the temperature sensor detects a temperature that is above a predetermined threshold, indicating an uncontrolled fire in progress. A portion of the water exiting the washing system is therefore drawn in the exhaust duct by the exhaust fan to thereby cool the exhaust duct and maintain it below a predetermined safety temperature. Furthermore, the exhaust fan also draws at least some of the smoke generated by the uncontrolled fire.

Catalytic purification process and device for exhaust gas from a combustion system

Abstract: The exhaust fumes (a) to be purified are led into a conversion and mixing channel (16) so that the exhaust gas (a) flow through said channel (16) in a predetermined longitudinal direction (18). A reducing agent (r), in particular an aqueous urea solution, is sprayed at the same time into the stream of exhaust gas (a) in the conversion and mixing channel (16). The stream of exhaust gas (a) is then deflected into a reaction channel (34) that is parallel to or surrounds the conversion and mixing channel (16), and in which the exhaust gas (a) flow in the opposite direction (32). A reduction catalyst (36, 38) that reduces the exhaust gas components (a) capable of being reduced is located in the reaction channel (34). The thus purified exhaust gas (a') are discharged from the reaction channel (34).

Pipe evaporator for feeding additional fuel into the exhaust gas

Abstract: A device for re-treating exhaust gases of an internal combustion engine is proposed, in which to promote the efficiency of a downstream reducing catalytic converter, fuel is metered via a metering valve and introduced into the exhaust system via an evaporator device. A metal sheath is provided with a sheathed glow-plug element that is used as the evaporator device and via a flow opening on a face end introduces an evaporated reducing agent into the exhaust gas stream.

Masonry heating system

Abstract: An inside-out heating method provides efficient and economical heating of wet cement during the curing phase in building structures. Hollow building blocks and their cement joints may be heated by applying forced hot air injected at the base of the wall. The hot air rises up through the wall and out of the open end of the top course of block by the chimney effect of the hot air rising through the ducting created by the aligned vertical passageways in the hollow blocks. The hot air is distributed through the wall by a manifold and injection tubes which provide air ducting from a heat source, such as a forced air propane heater. Temporary holes are broken through a low level course of block to receive the hot air injection tubes. After the cement has fully dried, the injection tubes are removed and the temporary holes are filled in with cement.

Method and apparatus for reducing NOx in the exhaust streams of internal combustion engines

Abstract: The invention discloses a method of reducing the concentration of NO x in the exhaust streams of internal combustion ignitions wherein a selected producing agent is introduced into the combustion chamber of such an engine via the fuel and/or air feed stream introduced into the combustion chamber. Also disclosed is an apparatus for reducing the concentration of NO x in the exhaust streams of internal combustion engines having a piston-cylinder assembly having an air fuel mixture contained therein, a means for storing a selective reducing agent selected from the group consisting of ammonia, hydrazine and cyanuric acid and a means for introducing the reducing agent into the lean air/fuel mixture before combustion occurs such that upon combustion of the air/fuel mixture, the reducing agent decomposes to react with one or more products of combustion to produce an engine exhaust stream having a reduced concentration of NO x .

Exhaust particulate purifier for internal combustion engine

Abstract: PROBLEM TO BE SOLVED: To regenerate a filter for scavenging particulates in exhaust gas in an exhaust particulate purifier which is operated even under a temperature to activate its catalyst by providing a fuel feed means in the upstream with respect to the filter and providing exothermic bodies of fuel absorbing structure between the fuel feed means and the filter. SOLUTION: When a filter 7 is to be regenerated, if the oxidation catalysts carried by a catalyst carrier 9 and by heating bodies 4 are not heated up to their activation temperature, heaters 42 are energized to heat the heating bodies 4 from their inside after which a fuel feed means 1 injects fuel droplets 8 into exhaust gas 2. When the resultant mixed gas passes near the heating bodies 4, the exhaust gas 2 streams while curving around the respective heating bodies 4 and thus does not hardly flow into fuel absorbing members 4, while the fuel droplets 8 travel straight against the heating bodies 4 and penetrate the fuel absorbing members 41 to be oxidized or burned therein and emitted out therefrom again into the exhaust gas. As a result, the exhaust gas flowing into the catalyst carrier 9 is heated up to heat the oxidation catalyst carried by the catalyst carrier 9 up to its activation temperature. COPYRIGHT: (C)1997,JPO

Method of using IC engine

Abstract: The operating method is for a turbocharged IC engine (1). A compressor is located in the intake and an exhaust turbocharger (2) is located in the exhaust gas flow (6). The turbine and compressor are on the same shaft. At idle, some intake air is bled from the intake. At shutdown, no more air is bled off. At idle, after fuel injection, extra fuel is injected and burnt, driving the turbine to bleed off the excess air. The excess air removed from the compressor (3) is expelled to the atmosphere through a control valve (9), thus creating a waste flow (10). Extra air demanded by the compressor takes a line into the exhaust manifold (7) at a point between the engine and the turbo. A particle filter (8) is mounted in the line into the exhaust.

Internal combustion engine exhaust gas purifier apparatus

Abstract: In order to activate an exhaust catalyst of an engine as quickly as possible from the engine restart, an exhaust damper for opening and closing an exhaust pipe is disposed downstream of a catalyst. A pneumatic actuator drives to open and close the exhaust damper. A negative pressure is introduced into a pressure chamber of the pneumatic actuator to close the exhaust damper after the engine is stopped. The closed exhaust damper keeps the warmth of the catalyst to ensure high exhaust gas purification performed when the engine is restarted. Alternatively, activation of the exhaust catalyst is enhanced by retarding the engine ignition timing and raising the engine idling speed.

Exhaust gas treatment unit

Abstract: An exhaust gas treatment unit of the combustion type is capable of effectively carrying out the decomposing treatment of an exhaust gas while at the same time allowing the unit to be reduced in size. The exhaust gas treatment unit includes a treatment drum, a combustion air introduction tube attached at one end of the treatment drum to introduce combustion air to the inside of the treatment drum, a fuel gas introduction tube disposed inside the combustion air introduction tube to introduce fuel gas to the inside of the treatment drum, and an exhaust gas introduction tube disposed inside the fuel gas introduction tube to introduce exhaust gas to the inside of the treatment drum. A flame tube extends from an end portion of the combustion air introduction tube on the air outlet side to the vicinity of the other end of the treatment drum, and a cooling air introduction port is provided for introducing cooling air into a space between the side wall of the treatment drum and the flame tube. By virtue of the presence of the flame tube, the fuel gas flame is kept for a longer period of time, thereby improving its contact efficiency with the exhaust gas.

Deterioration monitoring apparatus for an exhaust system of an internal combustion engine

Abstract: A deterioration monitoring apparatus for an exhaust system of an internal combustion engine includes an air-fuel ratio control system and a deterioration determining circuit. The air-fuel ratio control system controls an air-fuel ratio of exhaust emissions flowing downstream of a catalytic converter disposed in the exhaust system of the engine to agree with a target downstream air-fuel ratio under feedback control based on an air-fuel ratio of exhaust emissions flowing upstream of the catalytic converter and the air-fuel ratio of the exhaust emissions flowing downstream of the catalytic converter. The deterioration determining circuit determines whether the exhaust system such as an oxygen sensor mounted downstream of the catalytic converter or the catalytic converter is deteriorated or not based on the air-fuel ratio of the exhaust emissions flowing downstream of the catalytic converter and the target downstream air-fuel ratio.

Combined cycle engine

Abstract: A method of operation of an internal combustion engine to minimize NOx emission in the exhaust gas involving the detection of the load on the vehicle engine as either a low load or a high load. When a low load is detected, unthrottled air and a quantity of fuel providing for a lean combustion condition are mixed with the injection (4) of fuel adjacent top dead center during the compression stroke. When a high load condition is detected, throttled air and a quantity of fuel governed by the sensed oxygen content of the exhaust gas are mixed in an approximately stoichiometric ratio with the injection (4) at a much earlier time than the injection at low load, preferably during the intake stroke.

Fuel regulating mechanism for a rotary throttle valve type carburetor

Abstract: A fuel regulating method and mechanism for a rotary throttle (barrel-type) carburetor which prevents an end-user A/F adjustment that would cause increase in fuel quantity to a level in excess of a regulated value so as to comply with the exhaust gas emissions regulations. A cylindrical throttle valve having a throttle hole is disposed in an air intake passage of the carburetor body 12, the air flow is controlled by rotation of the throttle valve and the fuel flow is controlled by the position of a fuel regulating needle, attached to the throttle valve, relative to a fuel jet port of a fuel supply pipe in the carburetor body due to axial movement of the throttle valve. A bypass passage is provided within the carburetor body to communicate the throttle valve hole and fuel jet area with the air intake passage upstream of the throttle valve. An air flow regulating needle valve in the air passage is operable to adjust the bypass air flow in the air passage to lean the pre-set idle A/F ratio from a maximum rich factory adjustment. The fuel regulating needle valve is sealed to prevent exterior access by the end-user after making the factory adjustment.

Supercharged multicylinder internal combustion engine with exhaust recycling

Abstract: A supercharged multi-cylinder internal combustion engine is provided having exhaust recycling with air supply and exhaust outlet devices, variably controllable air intake and exhaust outlet valves, a first lubricating oil circuit, and an exhaust processing cylinder having a driven piston and a variable control for air intake and exhaust outlet valves on the exhaust processing cylinder. The air intake and exhaust outlet valves on the exhaust processing cylinder are each partially opened during a downward stroke of the driven piston of the exhaust processing cylinder by a control unit. A second lubricating oil circuit is provided for the exhaust processing cylinder.

3-Dimensional Simulation of Air Mixing in the MSW Incinerators

Abstract: Combustion control strategies to minimize the pollutants emission from municipal solid waste (MSW) incinerators are formulated based on the improved mixing of air with the products of incomplete combustion and the subsequent increase in oxidative destruction. Secondary air injection into the combustion chamber plays the key role in this mixing process. However, design variables of the air jet into the combustion gas stream are not clearly identified, and the performance of mixing and reaction is not fully understood. Three-dimensional flow simulation was performed to study the mixing performance of a full-scale incinerator combustion chamber according to the secondary air nozzle configuration. A detailed flow was analyzed and the degree of mixing was quantitatively evaluated by introducing a statistical parameter based on the chemical species distribution. The gas residence time distribution was analyzed using the particle trajectory. The overall flow field was strongly influenced by the nozzle c...

Piston combustion engine having a system for recirculating exhaust gases and system for use in such an engine

Abstract: In order to reduce the emission of harmful substances, in particular NOx, a system of exhaust gas recirculation (EGR) is used in piston combustion engines. A positive pressure difference between the exhaust and inlet volumes is needed in order to displace the exhaust gas. The invention provides a piston combustion engine including an EGR turbine (17) connected to a first portion of the exhaust manifold (5) and an EGR compressor (21) connected to a second portion of the exhaust manifold (5). As a result of this a balanced gas exchange in the exhaust portions of the engine is obtained.

Rotary valve apparatus for internal combustion engines and methods of operating same

Abstract: A rotary valve system mounted to an internal combustion engines and method of operating the system primarily comprises a rotary valve mounted within a valve sleeve, which is in turn mounted within a longitudinal bore extending through an intake and exhaust manifold. Controllers vary the rotational and axial position of the valve sleeve, which provides the capability of adjusting the amount of fuel mixture entering the combustion chambers of the engine and the timing of the intake of such mixture. The method of operation includes in taking fuel mixture into, and evacuating exhaust gas from, an internal combustion engine, wherein fuel mixture flows into the manifold, is directed across the valve sleeve, through the rotary valve, across the sleeve, and into a combustion chamber. After combustion of the fuel mixture, the exhaust gases are directed from the combustion chamber through the sleeve, through the rotary valve and into an exhaust chamber. Then the exhaust gases flow through the sleeve and into an associated manifold exhaust passage. An alternative embodiment of a rotary valve system primarily comprises a rotary valve body mounted within an intake and exhaust manifold, with the valve body and manifold constructed substantially identical to the first embodiment, but without a valve sleeve. This embodiment operates in a manner similar to the first embodiment, the ability to adjust the amount of fuel-air mixture or the timing of the intake of such mixture is limited.

Model-based cylinder-by-cylinder air-fuel ratio control for SI engines using sliding observers

Abstract: Exhaust stoichiometric air-fuel ratio is required for a 3-way catalytic converter to reduce exhaust emissions from an SI engine. Only when the combustion inside cylinders of an SI engine is kept close to its stoichiometric value can the catalytic converter then most efficiently reduce the harmful CO, HC, and NOx in the exhaust mixture. By this method the air pollution from the engine exhaust can be reduced. The purpose of air-fuel ratio (AFR) control is to maintain stoichiometric combustion in an SI engine. Currently one way to control AFR is by using the signal(s) from one or dual oxygen sensors installed on the exhaust pipes as a feedback signal to correct the fuel amount injected into intake manifold runner. The AFR signals obtained by such a method are mean values for the ratios in all cylinders. This makes a cylinder-by-cylinder control difficult. This paper proposes a new method for a cylinder-by-cylinder AFR control. In this method nonlinear state estimation is used to estimate the amounts of fuel and air being injested into each individual cylinder, and these air-fuel ratio signals are transmitted back to the electronic control module to correct the fuel amount injected into each runner port. The fuel mass in a cylinder is estimated by a cylinder pressure and combustion heat release observer, while the air mass into a cylinder is estimated by a runner-by-runner intake manifold pressure observer. This control method not only fulfils the AFR control cylinder by cylinder, but also may eliminate the need for conventional costly oxygen sensors.

Controlling apparatus for introduction air into an exhaust pipe of an internal combustion engine

Abstract: In an apparatus for controlling the introduction of air into an exhaust pipe of an internal combustion engine in which air is introduced from the intake side to the exhaust side to improve the efficiency of purifying exhaust gases, to prevent a decline in the purification efficiency of a catalyst in a state in which the exhaust gas temperature immediately after starting is low. A control valve 11 is provided in an air introducing pipe 9 for introducing air from the intake side to the exhaust side, and the control valve 11 is set in a shut-off state during starting or during starting and a predetermined time duration immediately after starting.