Showing papers on "Lean burn published in 1994"

Combustion exhaust purification system and method

Abstract: The present invention is particularly well suited for purifying exhaust from relatively large lean burn diesel engines. A computer controlled injector intermittently injects an optimal amount of NOx reducing fluid into the exhaust passageway from the engine. The optimal amount corresponds to an amount that will achieve optimal NOx reduction rates for the given engine operating condition and exhaust temperature. A computer periodically senses the engine operating condition and the exhaust temperature, and calculates the appropriate injection amount. With appropriate deNOx and oxidation catalysts located downstream from the injector, the exhaust purification system of the present invention has the ability to greatly reduce NOx content of the exhaust while maintaining HC emissions at acceptable levels.

Series combination catalytic converter

Abstract: The present invention is particularly applicable to lean burn engines that produce exhaust containing insufficient amounts of unburned hydrocarbons to satisfactorily reduce NOx emissions without undermining engine performance. In the exhaust purification system, ethanol or another suitable hydrocarbon is injected into the exhaust stream at an appropriate location between the engine and the catalytic converter. A deNOx catalytic converter is positioned within the exhaust downstream from the ethanol injection point. The combination engine application, ethanol injection and suitable deNOx catalyst combine to reduce NOx to satisfactory levels without producing significant amounts of undesirable secondary nitrogen containing compounds. An oxidation catalytic converter is positioned in the exhaust downstream from the deNOx catalytic converter. The oxidation catalyst serves to convert any remaining unburned hydrocarbons into carbon dioxide and water. At the same time, only small amounts of secondary nitrogen compounds are converted back into NOx compounds upon passage through the oxidation catalyst. The end result being an over all reduction in both HC and NOx compounds particularly for lean burn engines to satisfactory levels.

Device for reducing the amount of nitrogen oxides in the exhaust from a lean-burn internal-combustion engine

Abstract: In order to be able to design a device for reducing the amount of nitrogen oxides in the exhaust from a lean-burn internal-combustion engine to be particularly compact and short, it is proposed to combine an inlet chamber, a hydrolysis catalyst, a DeNOx catalyst and an oxidation catalyst in an essentially cylindrical unit through which the exhaust can flow in said sequence, where the diameter of the inlet chamber exceeds the diameter of the hydrolysis catalyst. The consequence of this is that the exhaust, which is mixed in the inlet chamber with a reducing agent, for example an aqueous urea solution, enters the subsequent catalysts with a particularly homogeneous reducing agent distribution and an exhaust flow density which is approximately uniform over the cross section and utilises these subsequent catalysts uniformly over the entire cross section. The novel device for reducing the amount of nitrogen oxides can in principle be integrated into any exhaust line of a lean-burn internal-combustion engine and can be adapted to internal-combustion engines having different power outputs.

In-cylinder crank-angle-resolved imaging of fuel concentration in a firing spark-ignition engine using planar laser-induced fluorescence

Abstract: We present a quantitative planar laser-induced fluorescence (PLIF) method for imaging the in-cylinderfuel concentration in a spark-ignition engine. The method is based on fluorescence from a carbonyl compound added to the fuel and excited by an excimer laser at 308 nm. The method has been applied to the study of charge stratification in a lean burn engine equipped with a four-valve pent-roof clinder head. In this engine, stratification is achieved by fuel injection through an inlet valve, the paths of rich fuel pockets from induction through compression to the point of ignition is shown by a series of crank-angle-resolved air-to-fuel ratio (AFR) images.

Method of reducing NOx emissions from lean-burn combustion engines

Abstract: The invention includes an operating strategy for zeolite-based catalysts used for reduction of NO x from highly lean exhaust conditions. The invention includes a method to enhance the high temperature activity of zeolite-based catalysts by modifying the transient feed composition without changing the overall time-average feed composition. More specifically, a cyclic operation method with alternating feed conditions between rich and lean to enhance the activity of zeolite-based catalysts to remove NO from lean exhaust gases when the overall exhaust composition contains a large amount of excess oxygen, without affecting the catalysts' activity to remove hydrocarbons. The rich to lean transient conditions are created by periodically adding hydrocarbon pulses from a different source to the combustion emissions.

Two-stage catalyst system for lean burn engines

Abstract: The present invention broadly relates to a catalyst system for promoting oxidation-reduction reactions of the exhaust gases produced by an internal combustion engine wherein the catalyst comprises a two-stage system of a first-stage nitric oxide removal (by reduction) catalyst and a second-stage carbon monoxide and hydrocarbon removal (by oxidation) catalyst. The first-stage catalyst comprises between about 0.1 and 3% by weight tungsten carried on a support material comprising mostly γ-alumina. The second-stage catalyst is an oxidation catalyst such as platinum on alumina.

Torch Ignition: Ideal for Lean Burn Premixed-Charge Engines

Abstract: Sluggish flame initiation and propagation, and even potential misfiring, become major problems with lean-fueled, premixed-charge, spark-ignited engines This work studies torch ignition as a means for improving combustion, fuel economy, and emissions of a retrofitted, large combustion chamber with nonideal spark plug location A number of alternative configurations, employing different torch chamber designs, spark-plug locations, and materials, were tested under full-load and part-load conditions Results indicate a considerable extension of the lean operating limit of the engine, especially under part-load conditions In addition, torch ignition can lead to substantial thermal efficiency gains for either leaner or rich air-fuel ratios than the optimum for the conventional ignition system On the richer side, in particular, the torch-ignited engine is capable of operating at maximum brake torque spark timings, rather than compromised, knock-limited spark timings used with conventional ignition This translates into thermal efficiency improvements as high as 8% at an air-fuel ratio of 20:1 and full load

Lean burn engine system

Abstract: PURPOSE: To obtain a lean burn engine system capable safely and economically supplying hydrogen. CONSTITUTION: In a fuel reforming part 20b of a plasma treating device 20, a mixed gas of gasoline fed through a second fuel route 16b and an exhaust gas from a main body 12 of an engine is made into plasma, an exhaust gas composition is made harmless and hydrogen and a lower hydrocarbon are formed from the gasoline in the mixed gas. The gas after treatment in the fuel reforming part 2Ob is supplied through an exhaust gas recycling line 46 to a route 12a at the suction side, mixed with air, blended with gasoline fed through a first fuel route 16a into a given air fuel ratio so as to carry out lean burn and supplied to a combustion chamber of the main body 12 of the engine. In the combustion chamber Of the main body 12 of the engine, hydrogen and gasoline formed in the fuel reforming part 20b is burnt to carry out stable lean burn. COPYRIGHT: (C)1995,JPO

Control system for lean-burn internal combustion engine

Abstract: ECU includes a lean air/fuel ratio coefficient setting device, an accelerated stoichiometric-burn operation air/fuel ratio coefficient setting device, a meeting-of-lean-burn-operation-conditions determining device, a throttle position change detector, an acceleration criterion setting device, an end-of-acceleration determining device and an acceleration determining device. When a detected vehicle speed has been determined to be in a high-speed range faster than a threshold and an acceleration is determined to have ended, a relatively large value is set as an acceleration criterion only for a predetermined period. During a lean-burn operation, ECU compares output information from the throttle position change detector with the acceleration criterion set by the acceleration criterion setting device and if the output information is greater than the acceleration criterion, determines an accelerated operation and changes the mixing ratio of fuel to air to a stoichiometric ratio (or a rich ratio). Otherwise, the air/fuel ratio is controlled at a lean ratio.

Verfahren und Vorrichtung zum Reduzieren von NO¶x¶ in den Abgasen von Kraftfahrzeugverbrennungsmotoren

Abstract: A reducing agent is supplied to the combustion chambers of a compression ignition or lean burn spark ignition engine to reduce the discharge of NOx in the exhaust gases. The agent which may be ammonia, hydrazine or cyanuric acid and may be contained in a Cetain improving solvent, is metered into the fuel in the fuel tank, to the air intake or to be recirculated exhaust gases or injected to the combustion chamber through a glow plug. The cyanuric acid may be in a sublimable powder form which is supplied in an amount dependent on the peak combustion temperature and transported by air from a fan. An organometallic additive may be metered to the fuel tank to provide cleaning of a regenerative particle trap in the engine exhaust.

Mazda advanced lean burn engine with new three-way catalyst

Abstract: A lean burn engine with a new type of three-way catalyst was developed in order to enhance the potential fuel efficiency of lean mixture operation. A combination of engine modifications and catalyst development extended the lean operating region across engine load and speed with no deterioration in NOx emission levels. A swirl generating port with low flow-restriction characteristics was developed in order to enhance the torque range of lean operation and the in-cylinder mixture distribution was optimized to suppress NOx emissions in high load lean operation. The catalyst has a base support material of zeolite coated with active metals including platinum, iridium, and rhodium and can not only oxidize HC and CO but reduce NOx even in lean exhaust gas, in addition to having all conventional three-way catalyst functions such as the simultaneous conversion of HC, CO and NOx in stoichiometric exhaust gas. A vehicle equipped with the engine showed a 11.6% improvement of fuel economy in the Japanese 10-15 mode emission test compared with conventional engines operating at a stoichiometric mixture. (A) For the covering abstract see IRRD 874988.

Catalytic denitrification of lean-burn engine exhaust gas with hydrocarbon

Abstract: In the catalytic redn. of NOx in exhaust gas from a lean-burn i.c. engine with hydrocarbon present or produced in the fuel, the catalyst comprises a mixt. of 2 components with little catalytic activity, the first being a Ti mordenite (I) and the second a mixed oxide. Also claimed is the catalyst per se.

Method for converting lean-burn engine exhust gases using a two stage catalyst system

Abstract: The present invention broadly relates to a catalyst for promoting oxidation-reduction reactions of the exhaust gases produced by an internal combustion engine wherein the catalyst comprises a first-stage high temperature catalyst and a second-stage lower temperature catalyst. The first-stage catalyst comprises between about 0.1 and 3% by weight tungsten carried on a support material comprising mostly γ-alumina. The second-stage catalyst comprises a base metal catalyst carried on a support material and preferably comprises between 0.1 and 6% by weight copper carried on a support material comprising mostly γ-alumina.

Purification of nitrogen oxide

Abstract: PURPOSE:To provide a catalyst and its reaction control method and system for reducing and purifying the nitrogen oxide in oxygen-containing combustion exhaust gas by using a hydrocarbon. CONSTITUTION:The purification is effected by causing an incomplete combustion of hydrocarbon with oxygen on the catalyst and allowing reaction between the incomplete combustion product and nitrogen oxide. By controlling the reaction conditions so that the amount of CO produced on the catalyst layer reaches a predetermined or higher concn., the catalyst can be used in the optimum conditions. The result from a reaction made between C3H8 and NO in the presence of 10% oxygen using CO-carrying mordenite catalyst shows that a high NO conversion ratio can be obtained under the conditions of a high CO yield rate. This method is effective in the purification of the nitrogen oxide in the exhaust gas emitted from diesel engine, lean burn gasoline engine, etc., to which the conventional denitration catalyst, catalytic converter rhodium, etc., are not applicable.

Engine with twin valve of fuel injection type

Abstract: PURPOSE: To stabilize ignition of fuel by an electrode of an injection plug so as to stabilize the combustion in the case of lean burn combustion at an operation range where the amount of intake is less by enabling a fuel injection valve to inject fuel mainly to the side of the electrode from the center of opening part of combustion chamber. CONSTITUTION: For every cylinder one intake valve 15 and one exhaust valve 16 are arranged in a cross flow manner. A fuel injection valve 20 for injecting fuel to combustion chamber opening parts 11a, 12a from the midway of an intake passage 11. Especially the valve 20 is arranged so that fuel is injected exclusively to the side of electrode 51 of an ignition plug 50 from the center of the opening parts 11a, 12a. Even in the case of lean combustion and low intake air fuel is injected mainly to one side of right and left. A portion of low air-fuel ratio is formed in a deviated manner at part of intake flow coming in the combustion chamber from the opening part 11a, 12a of the passage 11 and exists in the vicinity of the electrode 51. Stable ignition by the plug 50 is thus made possible. COPYRIGHT: (C)1995,JPO

Air-fuel ratio correcting method for internal combustion engine

Abstract: PURPOSE:To prevent the fluctuation of the air-fuel ratio to the rich side due to the response delay of an air-fuel ratio sensor in the case where the fuel supply is started again during the PID control by stopping the PID control for a predetermined time, and performing the movement to the PID control after passing the predetermined time. CONSTITUTION:In an internal combustion engine 100, a fuel injection valve 5 is provided in one end of an intake manifold 4 of an intake system 1. On the other hand, an air-fuel ratio sensor 21 is provided in the upstream side of the catalytic converter rhodium 22 of an exhaust system 20. Drive of a fuel control valve 5 is controlled by an electronic control device 6 at least on the basis of the detecting signal from the air-fuel ratio sensor 21. Namely, the PID control for correcting the fuel injection quantity on the basis of the air-fuel ratio correction factor is performed so as to obtain the target air-fuel ratio of the lean burn area. In this case, when the fuel supply is started again during the PID control, the PID control is stopped for a predetermined time, and after elapse of the predetermined time, movement to the PID control is performed.

Air-fuel ratio control device of lean burn engine

Abstract: PURPOSE:To restrain discharge of NOx during the time of changing an air-fuel ratio in most of an intake air flow rate region by changing changeover speed of the air-fuel ratio in accordance with a result of comparison between a computation result of a supplementary air flow rate and the maximum flow rate of a control valve. CONSTITUTION:Change-over speed of an air-fuel ratio at which it is changed over to a target air fuel ratio is enumerated by an enumeration means 33, and from this changeover speed and a drive condition signal, an enumeration means 34 enumerates a basic injection amount. In the meantime, an enumeration means 38 enumerates an increasing amount of the supplementary air flow rate by way of using the changeover speed of the air-fuel ratio and the drive condition signal so that torque becomes same before and after changing over at the time of changing over the target air-fuel ratio, and in accordance with the increasing amount of this supplementary air flow rate, a driving means 39 drives an air control valve. In this case, the changeover speed of the air-fuel ratio is set high until the supplementary air flow rate exceeds the maximum flow rate of the air control valve and low when it exceeds the maximum flow rate by a set setting means 41 in accordance with a judgement result of a judgement means 40.

Air-fuel ratio study method for internal combustion engine

Abstract: PURPOSE:To prevent fuel consumption from worsening by determining a correction amount of a fuel injection amount in a learn burn region from a fuel injection correction amount at feedback control time, calculating a difference between this correction amount and a target correction amount of fuel injection amount, and studying the correction amount of fuel injection amount in the lean burn region based on this difference CONSTITUTION:An ECU6 for controlling a fuel injection valve 5 of an engine 100 calculates a correction coefficient FLA for determining a fuel amount corrected for obtaining target air-fuel ratio in the case of control in a lean burn region by the target air-fuel ratio in a step 51 In a step 52, a difference FLAFDI from a target correction coefficient FLAFT, in the case of calculating the correction coefficient FLAF and a fuel injection amount in theoretical air- fuel ratio, is calculated By a value of this difference FLAFDI, a study is performed in steps 53 to 54 and steps 61 to 62, and as a result by obtained study value KQi, a fuel injection amount in the lean burn region is controlled in detail In this way, fuel consumption is prevented from worsening, to improve efficiency of an output

Method for purifying waste combustion gas and catalyst used for the method

Abstract: PURPOSE:To provide a method for purifying waste combustion gas generated from lean burn system and a catalyst used for the method. CONSTITUTION:The waste combustion gas containing small quantity of a lower hydrocarbon, nitrogen oxides, carbon monoxide and a large quantity of oxygen is allowed to react in the presence of the catalyst made by allowing gallium to be carried (carrying quantity is 0.1-10wt.%) on a carrier made of ZSM-5 type zeorite or ferrierite type zeorite. If necessary, a small quantity of a lower hydrocarbon is newly added into the waste combustion gas, total quantity of the lower hydrocarbon contained in the waste combustion gas and the newly added lower hydrocarbon is a quantity required for reducing and purifying nitrogen oxides contained in the waste combustion gas. The lower hydrocarbon contained in the waste combustion gas is 1-4C lower hydrocarbon and the newly added hydrocarbon consists of at least one kind of methane, ethane and ethylene.

Luft-Kraftstoffverhältnissteuerung für einen Motor

Abstract: When engine operating conditions are suitable, an ic engine control system switches from stoichiometric air fuel ratio control to a lean burn air fuel ratio control. During lean burn control the lean air fuel ratio target value is shifted towards rich by a correction coefficient calculated in dependence on detected engine instability. If the correction coefficient exceeds a preset value, then control reverts back from lean burn to stoichiometric control where NO emissions are controlled by a catalytic convertor. The reversion back to stoichiometric control can also be effected when the vehicles drive system is engaged, when a low gear is selected, when a gear change is effected or can be delayed until a set time after the coefficient exceeds the preset value. The aim is to achieve fuel efficiency whilst maintaining engine stability and low NO emissions.

Control device for internal combustion engine with automatic transmission for vehicle

Abstract: PURPOSE:To provide a control device for an internal combustion engine with automatic transmission for a vehicle whereby, for instance, both lean burn control and lockup control can be simultaneously performed without worsening riding comfortableness and drivability of the vehicle. CONSTITUTION:At the time of LC capacity feedback control by the second ECU, when an engine is transferred to a lean burn control condition, in the case of calculating target ME values MEFB3, MEFB4, by subtracting a target engine speed increasing predetermined value DMELEAN from a value of multiplying a car speed Vn by a 3rd-speed coefficient K3FB or a 4th-speed coefficient K4FB (step S6, S10), connecting force of a lockup clutch is adjusted to a level of connecting force or less before a transfer to lean burn control.

Emission control method

Abstract: PURPOSE:To efficiently purify NOx by arranging the crystalline silicate loaded with copper in the fore stage of an exhaust gas passage, arranging a three- component catalyst in series in the rearstage, and excessively adding fuel in a moment in a special case. CONSTITUTION:An exhaust emission control device is installed in the exhaust gas passage of a lean burn engine 1. A crystalline silicate catalyst loaded with copper is arranged in the forestage of the exhaust gas passage, and a three- component catalyst is arranged in the rearstage. The three-component catalyst consists of alumina carrier loaded with Pt and Rh. A throttle 5 and an air cleaner 6 are arranged on the suction side of the lean burn engine 1. An oxygen concentration sensor 2 is arranged on an exhaust side. When the exhaust gas composition changes from a lean state to a stoichio state, fuel is added excessively in a moment. Accordingly, NOx can be purified efficiently in any gas state.

The railplug: Development of a new ignitor for internal combustion engines. Final report

Abstract: A three year investigation of a new type of ignitor for internal combustion engines has been performed using funds from the Advanced Energy Projects Program of The Basic Energy Sciences Division of the U.S. Department of Energy and with matching funding from Research Applications, Inc. This project was a spin-off of {open_quotes}Star Wars{close_quotes} defense technology, specifically the railgun. The {open_quotes}railplug{close_quotes} is a miniaturized railgun which produces a high velocity plume of plasma that is injected into the combustion chamber of an engine. Unlike other types of alternative ignitors, such as plasma jet ignitors, electromagnetic forces enhance the acceleration of the plasma generated by a railplug. Thus, for a railplug, the combined effects of electromagnetic and thermodynamic forces drive the plasma into the combustion chamber. Several engine operating conditions or configurations can be identified that traditionally present ignition problems, and might benefit from enhanced ignition systems. One of these is ultra-lean combustion in spark ignition (SI) engines. This concept has the potential for lowering emissions of NOx while simultaneously improving thermal efficiency. Unfortunately, current lean burn engines cannot be operated sufficiently lean before ignition related problems are encountered to offer any benefits. High EGR engines have similar potential for emissions improvement,more » but also experience similar ignition problems, particularly at idle. Other potential applications include diesel cold start, alcohol and dual fuel engines, and high altitude relight of gas turbines. The railplug may find application for any of the above. This project focused on three of these potential applications: lean burn SI engines, high EGR SI engines, and diesel cold start.« less

Advanced hydrogen/method utilization technology demonstration. Final report

Abstract: The overall objective of the work was to seek homogeneous blend ratios of hydrogen:methane that provide ``leverage`` with respect to exhaust emissions or engine performance. The leverage sought was a reduction in exhaust emissions or improved efficiency in proportions greater than the percentage of hydrogen energy in the blended fuel gas mixture. The scope of the study included the range of air/fuel mixtures from the lean limit to slightly richer than stoichiometric. This encompasses two important modes of engine operation for emissions control; lean burn pre-catalyst (some natural gas engines have no catalyst) and post-catalyst; and stoichiometric with three-way catalyst. The report includes a brief discussion of each of these modes.

Catalyst for purifying exhaust gas from lean burn engine and purifying method

Abstract: PURPOSE:To provide the catalyst for purifying the exhaust gas from the lean burn engine using gasoline fuel and to provide a purifying method. CONSTITUTION:In the catalyst, the mixture consisting of the component of catalytic activity, containing at least one kind noble metal selected from the group consisting of platinum and paladium and at least one kind alkali metal oxide selected from the group consisting of potassium, sodium, rubidium and cesium, and a refractory inorg. oxide is deposited on an inactive carrier, and the exhaust gas from the lean burn engine using gasoline fuel is purified by the single catalyst or the combination of the catalyst and an oxidizing catalyst or a ternary catalyst.

Characteristics of Unburned HC from a Lean-Burn Prechamber Gas Engine.

Abstract: The characteristics of unburned HC from a prechamber were studied using a small sized single cylinder engine and a constant-volume combustion rig. It is thought that HC in exhaust gas is unburned fuel from a crevice volumes between a liner and a piston and between a liner and a head. When the compression ratio is higher, a ratio of the crevice volume to the combustion chamber is higher and HC increases. When the crevice volume reduces, the thermal efficiency improves because unburned fuel HC and CO reduce. When a hole angle of the prechamber is made larger, HC decreases. The flame jet from the larger hole angle can reach the liner wall. When the swirl intensity decreases, the thermal efficiency improves and NOx decreases, but HC increases. The flame jet is disturbed by the swirl and the flame propagates to the liner wall.

Catalyst for purifying exhaust gas and method of pcatalyst for purifying exhaust gas and method of purifying exhaust gas urifying exhaust gas

Abstract: CATALYST FOR PURIFYING EXHAUST GAS AND METHOD OF PURIFYING EXHAUST GAS A catalyst comprising an iridium supported on at least one carrier selected from the group consisting of metal carbides and metal nitrides for eliminating nitrogen oxides in exhaust gas in the presence of oxygen in excess of the stoichiometric quantity of oxidizing components for reducing components. The catalyst is effective for eliminating NOx in exhaust gas from lean burn engines such as lean burn gasoline engines and diesel engines containing excess O2 corresponding to an A/F ratio of 17 or over.

Control system for an internal combustion engine with lean burn

Abstract: An ECU 25 has a lean air/fuel ratio coefficient adjusting device 52, an air/fuel ratio coefficient adjusting device 53 for accelerated operation with stoichiometric combustion, a sensing device 58 which determines whether conditions are fulfilled for a lean burn, a device 59 which detects changes in the position of the throttle, an acceleration criterion adjusting device 62A, a device 62B which determines the end of acceleration and a device 62C which determines acceleration. If it is determined that the detected vehicle speed lies in a high-speed range which is higher than a threshold value and if it is determined that the acceleration is ending, a relatively large value is set for a predetermined time period as acceleration criterion. During lean operation the ECU 25 compares an initial item of information from the device 59 with the acceleration criterion set by the device 62A. If the initial item of information is greater than the acceleration criterion, the ECU 25 determines accelerated operation and changes the mixing ratio of fuel and air to a stoichiometric (or rich) ratio. Otherwise, the air/fuel ratio is adjusted to a lean ratio.