Abstract: A device for purifying the exhaust gas of an internal combustion engine includes a particulate filter carrying an active-oxygen releasing agent that can cause the sulfur poisoning, a SOx trap unit arranged upstream of the particulate filter, and a bypass section for making the exhaust gas mainly bypass said particulate filter when SOx is released from the SOx trap unit. Further, an exhaust choke valve for an exhaust brake is arranged between the SOx trap unit and the exhaust gas branch portion of the bypass section.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine includes plural catalysts provided in parallel. In a case where temperatures of the catalysts need to be raised, a catalyst is selected from among the catalysts and the exhaust gas is allowed to flow in the selected catalyst. In addition, the temperature of the selected catalyst is raised without using a reducing agent when the temperatures of the catalysts are lower than a temperature range in which the reducing agent can be purified. Alternatively, the reducing agent is supplied to the selected catalyst so as to raise the temperature thereof when the temperatures of the catalysts are equal to or higher than the temperature at which the reducing agent can be purified.

Abstract: An exhaust gas purifying device of the present invention comprises NOx trap catalyst including NOx trap material, catalytic metal and O2 storage material, NOx sensor, section for releasing NOx when NOx absorbed amount of the NOx trap catalyst reaches a specified amount, section for determining diagnosis conditions of the NOx trap catalyst, section for detecting termination of O2 release from the O2 storage material, and section for diagnosing O2 storage capacity according to output value (NO1) of the NOx sensor during a term from beginning of the oxygen concentration lowering by the NOx release section until termination of the O2 release and for diagnosing NOx reduction capacity of the catalytic metal according to output value (NO2) of the NOx sensor after termination of O2 release, wherein a speed of lowering oxygen concentration during the diagnosis is set so as to be slower than that during non-diagnosis.

Abstract: In a cold condition before a warming-up completion in a diesel engine, when an engine power is less than a predetermined value, an air excess rate is controlled to a second air excess rate being smaller than a target air excess rate set after the warming-up completion, thereby promoting a warming-up of an exhaust gas purification catalyst due to rise of an exhaust gas temperature, and when the engine power is more than the predetermined value, the air excess rate is controlled to a first air excess rate being larger than the target air excess rate, thereby decreasing HC emission quantity from a combustion chamber. Accordingly, a total emission quantity of HC at the clod condition is decreased.

Abstract: A diesel engine aftertreatment exhaust system uses catalyzed soot filters for particulate matter reduction and urea SCR catalysts for NOx reduction on diesel engines in a combined system to lower particulate matter and NOx at the same time. With this integral emission control system, diesel engines are able to meet ultra low emission standards.

Abstract: An exhaust purifying apparatus includes an exhaust throttle valve provided in an exhaust passage of the internal combustion engine for closing the exhaust passage to increase a pressure therein; a relief passage provided bypassing the exhaust throttle valve; a relief valve provided to be able to close the relief passage and to be open when receiving an increased pressure in the exhaust passage with closure of the exhaust throttle valve; fuel cut determining means for determining whether the engine is during fuel cut-off; and a relief-valve forcibly operating means for closing the exhaust throttle valve when the fuel cut determining means determines that the engine is during fuel cut-off, thereby removing condensed water accumulated in the relief passage to avoid faulty operations of the relief valve, and suppressing deteriorated fuel consumption upon operation of the relief valve.

Abstract: The method of treating a fuel lean exhaust containing NOX and SO2 includes splitting the exhaust into major and minor portions for flow through multiple flow paths each of which contains a particulate trap and an absorber containing a NOX oxidation catalyst and a nitrate absorbent. The major portion is passed through a flow path in the lean state at a first temperature to convert the NOX to nitrate and the SO2 to sulfate. After the first period of operation flows are switched so that one flow path receives a minor exhaust portion for a second period of time during which fuel is injected into that flow path along with diversion of a portion of exhaust from another flow path through a bypass.

Abstract: At the start of operation of an internal-combustion engine (S10,S12,S14), an exhaust flow is restrained (to raise the exhaust pressure) (S18), secondary air is supplied (S20), and the combustion air-fuel ratio (A/F) is set within the range of rich air-fuel ratios (S16, S22).

Abstract: The present invention provides for an NOx adsorber aftertreatment system for internal combustion engines which utilizes adsorber catalysts arranged in parallel. The exhaust flow from the engine is divided in a predetermined ratio between the two catalysts during lean operation (e.g. 50-50). At a predetermined regeneration time (for example, when the adsorber catalyst is 20% full), the exhaust gas flow is reduced through the parallel leg that is to be regenerated (e.g., 20% through the leg to be regenerated, 80% of the flow to the other leg). A quantity of hydrocarbon is injected into the reduced-flow leg in order to make the mixture rich. Since the flow has been reduced in this leg, only a small fraction of the amount of hydrocarbon that would have been required to make the mixture rich during full flow is required. This will result in a substantial reduction in the fuel penalty incurred for regeneration of the adsorber catalyst.

Abstract: When an internal combustion engine is in a cold state (S12), fuel is injected during compression stroke with burn air/fuel ratio controlled so as to produce a slight lean air/fuel mixture equivalent to or slightly leaner than a stoichiometric air/fuel mixture (compression S/L operation) (S14), and also exhaust gas flow is restrained (S16).

Abstract: In a diesel particulate filtering device 1A, 1B which is provided with a diesel particulate filter units 10, 20, 30 for cleaning exhaust gas, and in which cleaning of the exhaust gas and the recovery thereof are performed, diesel particulate filter controllers 60, 62 for determining a recovery time based on detected values PI, PO0, PO1, PO2 of exhaust pressure sensors 51 to 55 in an upstream side of said diesel particulate filter units 10, 20, 30 and a downstream side thereof are provided with determination-value update means 60a, 62a resetting determination values R0, R1, R2 for determining a recovery time by comparing the detected values, PO0, PO1, PO2 with a standard exhaust pressure value P0.

Abstract: A method for rapidly heating an emission control device in an engine exhaust uses excess air added to the exhaust via an air introduction device. After an engine cold start, the engine is operated to raise exhaust manifold temperature to a first predetermined value by operating the engine with a lean air-fuel ratio and retarded ignition timing. Once the exhaust manifold reaches the predetermined temperature value, the engine is switched to operate rich and air is added via the air introduction device. The added air and rich exhaust gas burn in the exhaust, thereby generating heat and raising catalyst temperature even more rapidly. The rich operation and excess air are continued until either engine airflow increases beyond a pre-selected value, or the emission control device reaches a desired temperature value. After the emission control device reaches the desired temperature, the engine is operated substantially around stoichiometry.

Abstract: An exhaust passage (20) of an internal-combustion engine (1) is provided with an exhaust emission control unit (40) capable of reducing harmful substances in exhaust gas under a given exhaust pressure condition and an exhaust sensor (22) for detecting the concentration of a specific exhaust component (H2, O2) in the exhaust gas, and a performance lowering identifying unit identifies lowering of the performance of the exhaust emission control (40) by detecting a failure to fulfill the given exhaust pressure condition in accordance with the output of the exhaust sensor.

Abstract: A pair of particulate filters arranged in parallel in an exhaust passage and a combustion device for supplying to the filters exhaust gas having a temperature elevation capability higher than the temperature elevation capability of the engine exhaust gas able to raise the filter temperature are provided. An NOx catalyst and oxidizing substance are carried on each filter. When the NOx absorbed in an NOx catalyst should be reduced, the flow of engine exhaust gas into the filter carrying the NOx catalyst for reduction of the NOx is suppressed and a rich air-fuel ratio exhaust gas is supplied from the combustion device to the filter so that the filter temperature is maintained higher than a particulate continuous oxidation temperature in the NOx reduction temperature range.

Abstract: An exhaust control valve (24) is arranged in an exhaust pipe (22) of an internal combustion engine. At the time of engine startup and warmup operation, the exhaust control valve (24) is substantially fully closed, the amount of injection of main fuel is increased from the optimum amount of injection at the time when the exhaust control valve is fully opened, auxiliary fuel is additionally injected during the expansion stroke, and thereby the unburned hydrocarbons exhausted into the atmosphere is greatly reduced at the time of engine startup and warmup operation.

Abstract: A bypass for an exhaust system for a utility vehicle, such as a combine, that, when substantially closed, provides maximum noise attenuation for road transport, i.e., relatively high back pressure, and then, when substantially open, would provide a reduced flow restriction, i.e., relatively low back pressure, for full power, field operation. A bypass flow path in an exhaust pipe is located upstream of a primary muffler. A diaphragm can be provided to manipulate a damper which acts to close the exhaust flow to the primary muffler and open the bypass to an exhaust pipe to effectively bypass the primary muffler.

Abstract: A device for supplying exhaust gases from an internal combustion engine to a catalytic converter, having multiple exhaust gas supply lines including at least one exhaust gas supply line that serves as a heat-conveying line to promote a transfer of exhaust gas heat to the catalytic converter and at least one other exhaust gas supply line that serve as a heat exchanger to promote an extraction of heat from the exhaust gas upstream of the catalytic converter. A switchable control mechanism controls a flow cross-section of at least one of the exhaust gas supply lines.

Abstract: A method and an apparatus for posttreatment of exhaust gases of internal combustion engines after an engine operation includes an intake system and an exhaust gas treatment system with an exhaust gas catalytic converter. Secondary air that originates in an air source can be delivered to the exhaust gas treatment system at a first secondary air inlet. After an engine operation, with the exhaust gas catalytic converter at operating temperature, the throttle device in the intake system is closed. After the engine operation, the engine is shut off in a phase relationship in which inlet/outlet valves of at least one combustion chamber of the engine are open. By means of the air source, an air flow is generated, which discharges at a further inlet point in the intake system of the engine and flows through or bathes the components in the direction of the exhaust gas catalytic converter at operating temperature in the exhaust gas treatment system.

Abstract: A particulate filter (22) is arranged in an exhaust passage of an engine, while an exhaust throttle valve (45) is arranged in the exhaust passage downstream of the particulate filter (22). The exhaust throttle valve (45) is fully closed once, then fully opened cyclically. At that time, the flow velocity of the exhaust gas is increased for just an instant in a pulse-like manner, whereby masses of particulate are separated from the particulate filter 22 and discharged.

Abstract: A method for improving a purge conversion efficiency of a Lean NOx Trap coupled downstream of a lean-burn internal combustion engine is presented. This method recognizes that during a purge of the LNT, its temperature increases due to the exothermic reactions in the LNT. Once the LNT temperature exceeds a certain threshold, further increases lead to a reduction in the NOx storage capacity, and therefore an increase in NOx emissions during the purge of the LNT. Therefore, it is proposed to cool the LNT temperature once the threshold is exceeded. This method improves emission control and fuel economy during purge.

Abstract: In an exhaust system for an internal combustion engine having two groups of cylinders with a separate exhaust line for each cylinder group, each including an upstream catalytic converter and a downstream catalytic converter and a control valve, a first transverse connection extending between the exhaust lines upstream of the upstream catalytic converters and a second transverse connection extending between the exhaust lines between the upstream and downstream catalytic converters, the valves are so arranged and controlled that, during warm-up, the exhaust gases from both cylinder groups flow through the upstream catalytic converter of one, and the downstream catalytic converter of the other exhaust line for rapid heat up of one of the catalytic converters in each of the exhaust lines.

Abstract: In order to prevent that a liquid reducing agent in a selective catalytic reduction system freezes, there are provided additional resistor heating elements on the pressure sensor diaphragm of the pressure sensor that is present in the reducing agent feed system. The same technique is applied in the production of the heating sensors as in the production of the sensor resistance network. The use of the sensor diaphragm surface for the electrical heating of the liquid reducing agent (e.g., aqueous urea solution) eliminates the need for additional installation space, sealed areas, and connectors for the electrical supply and triggering mechanism.

Abstract: A device for purifying exhaust gas of diesel engines, in which an oxidizing catalyst, a diesel particulate filter, and an Nox occluding/reducing catalyst are successively disposed in an exhaust gas passage of the diesel engine from the upstream side of the passage, the device for purifying exhaust gas of diesel engines comprising a bypass that connects the upstream side of the oxidizing catalyst with the downstream side thereof in the exhaust gas passage, an exhaust gas passage change-over means for changing-over the exhaust gas flow into either the oxidizing catalyst or the bypass, an air-fuel ratio control means for controlling the air-fuel ratio of the exhaust gas, an NOx occlusion amount detector means for detecting the amount of NOx occluded by the NOx occluding substance, and a controller.

Abstract: A fault determining apparatus for an exhaust passage switching valve which is capable of directly, rapidly and properly determining a fault in an exhaust passage switching valve, under conditions such as immediately after the start of an internal combustion engine, in which the switching valve should be essentially operated, without the need for setting a special fault determining mode. The fault determining apparatus determines a fault in the exhaust passage switching valve for switching an exhaust passage of exhaust gases discharged from an internal combustion engine between a main exhaust passage having a three-way catalyst and a bypass exhaust passage having filled in an intermediate portion thereof an adsorbent capable of adsorbing hydrocarbons and moisture in the exhaust gases in accordance with an activated state of the three-way catalyst.

Abstract: In an engine intake A/F ratio control system in an outboard engine system, a secondary air passage (P) for supplying secondary air for regulating the A/F ratio of an air-fuel mixture is connected to a carburetor (33) in an intake system of an engine (E), and a duty control valve (68) is connected to the secondary air passage (P). A duty control unit (92) is connected to the duty control valve (68) for controlling the duty ratio of a pulse applied to a coil (76) of the duty control valve (68), and an LAF sensor (94) is mounted to an exhaust system for detecting an A/F ratio of an exhaust gas to input a detection signal proportional to the A/F ratio of the exhaust gas to the duty control unit (92).

Abstract: A heavy duty diesel engine having an exhaust system incorporating a catalyst to convert NO to NO2 and a particulate trap on which soot particles are continuously oxidized, and a portion of the exhaust gases are recirculated through a cooler and exhaust gas flow valve before being mixed with air and fed to the engine cylinders. The system also incorporates a sensor to detect the amount of NOx in the exhaust to adjust the gas flow valve, thereby adjusting the portion of recirculated exhaust gas fed to the engine cylinders.

Abstract: A method for operating an exhaust-gas cleaning system having an NOx adsorption accumulator and an SOx trap, includes, in normal operating phases, feeding the exhaust gas to be cleaned first via the SOx trap and then via the NOx adsorption accumulator. The normal operating phases are from time to time interrupted by desulphurization phases for desulphurizing the SOx trap. Means are provided for controlling the direction of flow of the exhaust stream so that it optionally passes firstly via the SOx trap and then via the NOx adsorption accumulator, or firstly via the NOx adsorption accumulator and then via the SOx trap, so that during the desulphurization phases the exhaust gas can be passed firstly via the NOx adsorption accumulator and then via the SOx trap.

Abstract: An exhaust purification device comprising a first catalyst and a second catalyst arranged in the engine exhaust passage downstream of the first catalyst. An exhaust control valve is arranged downstream of the second catalyst. When the reducing components in the exhaust gas should be mainly oxidized by the first catalyst, the exhaust control valve is substantially fully closed and auxiliary fuel is additionally injected into the combustion chamber. When the reducing components in the exhaust gas should be mainly oxidized by the second catalyst, the exhaust control valve is fully opened and injection of auxiliary fuel is stopped.

Abstract: Exhaust gas sensors or air-fuel ratio sensors for generating outputs depending on the concentration of HC are disposed respectively upstream and downstream of an HC adsorbent in an exhaust passage. When an exhaust gas emitted from an internal combustion engine is supplied to the exhaust passage to allow the HC adsorbent to adsorb HC in the exhaust gas, an amount of HC adsorbed by the HC adsorbent per unit time is determined based on the difference between outputs from the exhaust gas sensors. A deteriorated state of the HC adsorbent is evaluated by comparing the determined adsorbed amount of HC and its integrated value with a threshold set depending on a temperature or the like of the HC adsorbent.

Abstract: An exhaust passage control valve has a valve element of a spiral shape mounted on a valve seat portion of a housing through which exhaust gases from an engine pass. The valve element is urged by a valve spring in a direction of closing the valve. A spring constant of the valve spring is kept low without enlarging the valve spring, and there can be obtained opening and closing characteristics in that the valve opens at a stretch when an exhaust-gas pressure has reached a predetermined value. As the valve spring, a helical torsion spring having a coiled cylindrical body portion is used. Arm portions on both ends of a coiled cylindrical body portion are engaged with a pair of spring receiving members. The spring receiving members are disposed in the housing on circumferentially opposite sides of the valve seat portions. The arm portion are engaged with the spring receiving members so as to be slidable in a longitudinal direction of the arm portions.

Abstract: A hybrid vehicle driven using power from an internal combustion engine and power from an auxiliary power source, includes an exhaust gas purification catalyst disposed in an exhaust passage of the engine. The catalyst stores oxygen and a power controller causes the engine to discharge exhaust gas including excess oxygen and causes the auxiliary power source to assist the engine in driving the vehicle when oxygen is to be stored in the exhaust gas purification catalyst. It is possible to supply the catalyst with exhaust gas containing excess oxygen while inhibiting the driveability from being adversely affected.

Abstract: An improved exhaust gas control device that has a hollow diverter pipe to divert exhaust around the muffler and in which a gate valve is slidably mounted to open and close the hollow pipe thus either forcing the exhaust gas through the muffler or diverting it to the atmosphere.

Abstract: An NOx absorbent is arranged in an engine exhaust passage absorbs NOx when the air-fuel ratio of inflowing exhaust gas is lean and discharges absorbed NOx or SOx when the oxygen concentration of inflowing exhaust gas decreases. When the air-fuel ratio of the exhaust gas flowing into the NOx absorbent is rich, previously absorbed NOx or SOx is discharged from the NOx absorbent. When NOx or SOx is to be discharged from the NOx absorbent, oxygen is left in the exhaust gas flowing into the NOx absorbent and the oxygen concentration of this exhaust gas is maintained within a predetermined range.

Abstract: In the case of an internal combustion engine (1) arranged transversely in a motor vehicle and having in-line cylinders, the exhaust gases are passed forwards in the direction of travel around the internal combustion engine from that side of the latter which is opposite to the direction of travel and, from there, pass to a catalytic converter (8) arranged in the rear area of the motor vehicle. To ensure rapid heating of the catalytic converter when cold-starting, the exhaust manifold (2) of the internal combustion engine is connected to the inlet of the catalytic converter (8) by a short feed line (5) with a small cross section. An exhaust-gas recirculation line (15) which opens into line (4) close to the catalytic converter is provided.

Abstract: In an exhaust gas purification device, a catalytic converter containing selective reduction catalysts is disposed in an exhaust gas passage of an internal combustion engine capable of being operated at a lean air-fuel ratio. The catalytic converter includes a plurality of the selective reduction catalysts disposed in series in the casing of the catalytic converter. Bypass passages which supply the exhaust gas to downstream selective reduction catalysts in the casing by bypassing the upstream catalysts are provided. When a reducing agent is supplied to the exhaust gas upstream of the converter, a part of the supplied reducing agent directly reaches the downstream selective reduction catalyst through the bypass passages without being oxidized by the upstream selective reduction catalysts. Therefore, the NOx purifying abilities of the downstream catalysts are improved and the formation of sulfates on the downstream catalysts is suppressed.

Abstract: A method (100) and system (10) for controlling the temperature of a first NO.sub.x trap in an aftertreatment system for a variable displacement engine (12). The frequency of switching between first and second cylinder banks (14, 16) of said variable displacement engine (12) controls the temperature of the NO.sub.x trap (18) in order to maintain the temperature within a preferred operating temperature range. A set of control valves (V1, V2, V3) is used to direct the flow of exhaust from alternate cylinder banks (14, 16) through various paths in order to maintain the desired temperature of the first NO.sub.x trap (18). In another embodiment (30), the aftertreatment and method (120) include a second NO.sub.x trap (26) for situations in which both engine banks (14, 16) are run simultaneously.

Abstract: An exhaust recirculation of gases in internal combustion engines, notably for automobiles, which has a catalytic converter, recycling apparatus for recycling the exhaust gases and heat recovers apparatus for recovering heat from the exhaust gases. A single heat exchanger is arranged for cooling the recycled exhaust gases and recovering the heat energy from the exhaust gases for heating the passenger compartment of the vehicle and for protecting the catalytic converter from excessively high exhaust temperatures. Valves for diverting exhaust gases, a back-pressure valve and an EGR valve are controlled for this purpose by control electronics. The invention is particularly applicable to direct-injection petrol or diesel engines or to lean-mixture petrol engines.

Abstract: A compact reversing flow catalytic converter for reducing noxious substances in exhaust gases produced by internal combustion engines is described. The catalytic converter includes a valve unit which reversibly directs exhaust gases through a container filled with catalytic material. The container defines a U-shaped gas passage which communicates with two ports at a top of the container. The valve unit is mounted to the top of the container and includes an intake and an exhaust cavity. The valve unit includes a valve disk having two openings therethrough and rotates around a perpendicular central axis between a first and second position. In each position, each opening communicates only with one of the cavities and one of the ports. In the first position, the exhaust gases enter the exhaust cavity from an exhaust pipe and pass through one of the openings into the gas passage where they contact the catalytic material as they travel through the U-shaped gas passage and enter the exhaust cavity.

Abstract: An exhaust manifold device is provided to allow air to enter an exhaust manifold during normal operation of an engine to prevent exhaust gases being sucked into the cylinders via exhaust valves. Air can be supplied via valves (18 and 21) to the exhaust manifold as required and is supplied to the valve (21) at pressures, above atmospheric pressure, that increase with engine speed.

Abstract: A method and an apparatus for reducing harmful emissions in the exhaust gases of an internal combustion engine which may be a Diesel engine or an Otto engine operated by a lean fuel air mixture. The exhaust gases are subjected to a catalytic treatment for oxidizing carbon monoxide and hydrocarbons, and the exhaust gases are throttled to increase their temperature under operative conditions of heat deficiency such as at cold start. The exhaust gases are subjected to an additional catalytic treatment for reducing nitrogen oxides in a deoxidation means. The throttling of the exhaust gases is controlled such that the temperature of the exhaust gases will be within a predetermined temperature range at which said deoxidation means is operative.

Abstract: In order to reduce the exhaust gas emissions of automotive vehicle combustion engines including exhaust gas catalytic converters, the exhaust gases are caused to flow between the engine and the catalytic converter through conduit branches of different thermal caracteristics. Said conduit branches comprise a full load tube and a partial load tube, with the full load tube surrounding the partial load tube so as to provide an annular space between the full load tube and the partial load tube.

Abstract: An exhaust gas purifying device for an engine comprises an exhaust gas purifying catalyst arranged in the exhaust passage. The catalyst is capable of reducing NO.sub.X in the catalyst in the oxidizing atmosphere, and comprises a reducing agent adsorbent adsorbing a reducing agent in the inflowing exhaust gas therein when the pressure in the adsorbent becomes higher, and desorbing the adsorbed reducing agent therefrom when the pressure in the adsorbent becomes lower. An exhaust gas control valve is disposed in the exhaust passage downstream of the catalyst. When both the engine load and the engine speed are low, the opening of the valve is made smaller to increase the pressure in the catalyst. At this time, hydrocarbon is fed to the catalyst, and is then adsorbed in the catalyst. When the engine load or the engine speed becomes high, or the cumulative amount of hydrocarbon fed to the catalyst becomes larger than a predetermined amount, the valve is made fully open to reduce the pressure in the catalyst.

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.

Abstract: In a state in which the engine is unloaded and the number of engine rotation is low, an overlap period of time during which the intake valve and the exhaust valve are both open is extended during the cold time, as compared with during the warm time. The extension of the overlap period of time causes gases remaining in the cylinders to increase, thereby making the burning of the fuel slow and elevating the temperature of the exhaust gases to thereby elevate the temperature of the cylinder head of the engine. A variation in the number of engine rotation, particularly a decrease in the number of engine rotation, resulting from the increase in the residual gases can be prevented by increasing the amount of intake air. Further, the temperature of the cylinder head can be elevated due to an increase in the amount of the supplied fuel resulting from the increase in the amount of the intake air.

Abstract: An exhaust pipe of an internal-combustion engine in which self-regulating throttle element is arranged behind the catalyst. In the warm-up phase of the internal-combustion engine, the throttle element closes off the exhaust pipe almost completely. The resulting increased exhaust back pressure causes a higher mass flow rate of the engine, whereby the exhaust gas temperature rises and the catalyst is warmed up rapidly.

Abstract: An exhaust control system has a first catalytic device disposed in an exhaust line and a second catalytic device, which is smaller in capacity than the first catalytic device, disposed in the exhaust line upstream from the first catalytic device. The system includes a shutter device disposed in the exhaust line upstream from the first catalytic device. The shutter device is caused, by a controller, to close the exhaust line during a predetermined period from a start of engine cranking, before an engine is warmed up, and open the exhaust line after the engine is warmed up, thereby promoting activation of the catalytic devices.

Abstract: In a steam condenser erected on-floor, in which the steam is precipitated on pipes through which cooling water flows and which are combined into separate clusters (2), the pipes of a cluster, which are arranged in rows, enclosing a cavity (13), a cooler (14) for the non-condensable gases is arranged in the cavity. The component clusters (2) are aligned horizontally in their longitudinal extent and are arranged vertically above one another. The cooler (14) for the non-condensable gases has its suction effect directed towards a zone below the longitudinal center line of the individual cluster.

Abstract: An engine exhaust apparatus in which an exhaust passageway of the engine is provided with a plurality of sound deadening passsages. One common exhaust passageway from the engine is branched into first and second exhaust passageways. Each of the first and second exhaust passageways has a silencer or muffler including first and second exhaust outlet tubes with a shift valve mounted in one of these exhaust outlet tubes. A control unit controls the shift valves to close both when engine speed is in a low region, to open one of them when engine speed is in a medium region and to open both when engine speed is in a high region.

Abstract: A gas silencing system for controlled sound attenuation of the exhaust gas in a motor vehicle comprises a sound attenuation muffler for exhaust gases. The system also includes means providing a bypass passage for gas to flow around at least part of the muffler. Bypass control valve is provided to allow selective regulation of the flow of exhaust through the muffler and the pass-pipe. The bypass control valve is responsive to a modulated pressure signal controlled by the driver of the vehicle. The invention also includes circuits for visually indicating the amount of bypass flow and the sound level of gas leaving the system.

Abstract: A multistage catalytic reactor for purifying exhaust gas has a passage for communicating exhaust gas to first and second catalyst bed assemblies, and a valve for automatically maintaining flow of the gas solely through the first catalyst bed assembly in response to a first operating condition and for automatically passing the gas through the first and second catalyst bed assemblies in response to a second operating condition, shifting of said valve being free of external control.