Abstract: The present invention has for its problem to be solved to provide a technique in which in an exhaust gas purification system for an internal combustion engine with a filter being arranged on an exhaust passage for trapping PM in an exhaust gas, it is possible to suppress an excessive rise in temperature of the filter during execution of filter regeneration control more preferably. In the present invention, when the amount of intake air in the internal combustion engine decreases up to an amount at which an excessive rise in temperature of the filter might be induced during the execution of filter regeneration control, the oxygen concentration of an ambient atmosphere around the filter is decreased up to a target oxygen concentration.

Abstract: An apparatus for the reduction of nitric oxides (NOx) and particulate matter of exhaust emissions from a diesel engine having an electronic control module. The apparatus includes a first treatment device for reducing particulate matter and a second treatment device for reducing NOx emissions from the engine exhaust. The apparatus also includes a first valve in fluid communication with the exhaust inlet from the engine and a second valve in fluid communication with a common exhaust outlet. The first and second valves are in fluid communication with each other through a fluid connection extending therebetween.

Abstract: A method for monitoring the efficiency of a catalyst includes providing an oxygen sensor between an engine and the catalyst to generate an output signal indicative of oxygen content. The output signal is sampled to provide a first value indicative of the oxygen content of untreated exhaust. The exhaust is allowed to flow through the catalyst to produce treated exhaust and then the treated exhaust is caused to flow back to the oxygen sensor. The output signal is again sampled to provide a second value indicative of the oxygen content of treated exhaust. The second value is compared to the first value to provide an indication of the efficiency of the catalyst.

Abstract: An exhaust gas purifying system causes less torque fluctuation and is capable of preventing the occurrence of white smoke in a regeneration control operation for regenerating a continuous regeneration DPF 3. When the continuous regeneration DPF 3 with an oxidation catalyst 3Aa on the upstream side of a filter 3Ab is controlled to regenerate, an exhaust throttle valve 31 provided in an exhaust passage 2 is closed and a delay multi-step injection control is performed to increase the temperature of the exhaust gas if an exhaust temperature T1 at the inlet of the oxidation catalyst 3Aa is less than the activation temperature Ta of the oxidation catalyst.

Abstract: The invention concerns diesel particulate filter regeneration in an exhaust system of a vehicle having a diesel engine. The particulate filter regeneration is selectively accomplished by actuating a particulate filter backpressure valve located downstream of the diesel particulate filter. Exhaust noise is attenuated for both normal driving and regeneration modes of operation by directing the exhaust flow through different flow paths in a muffler downstream of the diesel particulate filter.

Abstract: The invention concerns an internal combustion engine exhaust line comprising an active noise reduction system with variable choke device, continuously regulated based on the instantaneous discharge rate pulses of exhaust gases exiting from the internal combustion engine, including an expansion chamber for closing phases of the variable choke device arranged upstream of said active noise reduction system and a cavity dispersing medium and high frequencies arranged downstream of the active noise reduction system. The expansion chamber for the closing phases of the variable choke device is integrated in a first depolluting system arranged upstream of said active noise reduction system.

Abstract: An exhaust manifold includes an open/close valve that switches between either closing or opening the exhaust path of a collection section, and switches the exhaust path of the exhaust gas between passing through or not passing through a bypass path containing an upstream catalyst. There is a partition wall structure in a pipe-mounting member so that when the valve is closed such that the exhaust gas during cold start is led to the upstream catalyst, the exhaust paths for each of the branch pipes on the upstream side of the valve inside a collection section are independent from one another. When the valve is closed, the downstream side of each of the branch pipes is not continuous inside the collection section, so the flow of air is prevented in this section, and exhaust interference and loss of exhaust heat are reduced.

Abstract: Exhaust passage control valve 10 may comprise housing 30, valve member 20, and helical torsion spring 40. Housing 30 has an exhaust passage. Exhaust gas from an internal combustion engine flows through the exhaust passage of the housing 30. Valve member 20 opens and closes the exhaust passage of the housing. Helical torsion spring 40 may be disposed at the opposite side of the valve member from the housing side thereof. Helical torsion spring 40 comprises a coil part wherein spring wires have been wound in a coil shape, and arms formed at both ends of the coil part. The coil part may be disposed at approximately the center of the valve member. When the arms bend with respect to the coil part, the counter-force of this bending energizes the valve member towards a closing side. The spring mounting member may be arranged and constructed to adjust a position in which the spring mounting member is mounted on the housing such that a rotation angle of the arms can be changed.

Abstract: There is provided an exhaust pressure-adjusting valve that is brought into a closed position due to a biasing force of a resilient body and is opened against the biasing force of the resilient body due to the exhaust pressure in an exhaust channel, which is raised in response to the closing of a throttle valve, in which valve-opening area is increased or decreased according to the displacement of the resilient body, to thereby adjust the exhaust pressure. The exhaust pressure-adjusting valve has a unit for changing the growth rate of the valve-opening area, which gradually heightens the growth rate of the valve-opening area with respect to the displacement of the resilient body in a valve-opening direction.

Abstract: A wall-flow particulate trap system regenerated by reverse flow of filtered exhaust gas through porous walls of a plurality of tubular passages is disclosed. The system includes a particulate trap having an inlet and an outlet, the particulate trap adapted to receive engine exhaust gas; a mode valve assembly offset from the inlet of the particulate trap; a remote actuated relief valve offset from the outlet of the at least one particulate trap a duct rotor intermediate the particulate trap and the mode valve assembly, the duct rotor having a first end and a second end, the second end of the duct rotor in operative communication with the mode valve assembly and the first end of the duct rotor in fluid communication with the inlet of the particulate trap; and a rotor drive in driving connection with the duct rotor.

Abstract: An exhaust gas aftertreatment device for an internal combustion engine comprises an inlet configured to receive the exhaust gas, an outlet from which the exhaust gas exits the device, a first passageway defined between the inlet and the outlet, and a second passageway defined between the inlet and the outlet, wherein the second passageway is separate from the first passageway. A first aftertreatment element is disposed in the first passageway. In one embodiment, the device is a diesel oxidation catalyst device and the second passageway represents a bypass passageway. The second passageway may further have a second aftertreatment element disposed therein. In an alternative embodiment, the device is a NOx aftertreatment element, and a second aftertreatment element is disposed in the second passageway. In either case, the device includes an exhaust gas flow control mechanism configured to selectively control exhaust gas flow through the first and second passageways.

Abstract: A system for measuring NOx content of an exhaust gas produced includes at least one controllable valve operable to direct exhaust gas to a NOx sensor only when measurement of the NOx content is desired and to otherwise expose the NOx sensor to ambient air. A control circuit controls the operation of the at least one valve and determines the NOx content of the exhaust gas based on sensory data received from the NOx sensor.

Abstract: A reconfigurable exhaust system provides selective positioning of exhaust gas treatment devices either near, or spaced from, the exhaust gas outlet port of a turbine of a turbocharged Diesel engine. In some embodiments, auxiliary air or a heat exchanger are arranged to cool the exhaust gas when required.

Abstract: A diesel engine exhaust system includes a NOx absorber and a diesel fuel fired burner operated at an enriched fuel-to-air ratio to generate a sufficient quantity of CO and H2 for regenerating the NOx absorber. A method of operating a diesel exhaust system is also disclosed.

Abstract: A 4-cycle engine for a motorcycle has a secondary-air supplier for supplying secondary air to exhaust ducts. The engine includes a recess, which is depressed toward the engine, on a cylinder-head cover for holding a control valve of the secondary-air supplier. The recess and the control valve are positioned between two innermost cylinders of the array of the cylinders. Check valves, which are connected to downstream regions of the control valve, are each disposed between two outermost cylinders of the array of the cylinders.

Abstract: An emission reduction apparatus includes first and second exhaust paths carrying respective first and second Nox traps. One trap has a smaller capacity than the other and is operative while the larger trap regenerates, allowing symmetric operation.

Abstract: Normally, at the time of cold-start of an internal combustion engine or the like, the flow of exhaust in an exhaust passage of the internal combustion engine is suppressed or two-stage combustion is carried out so as to promote exhaust purification in an exhaust system. However, when a correlation value of a braking force required to be generated by a vacuum type brake booster is greater than a correlation value of a braking force that can be actually generated by the vacuum type brake booster, a restricting device restricts the suppression of the exhaust flow or a two-stage combustion prohibiting device prohibits the two-combustion.

Abstract: A diesel engine (1) has an exhaust system (4) and an oxidation catalyst (5a). Exhaust gas for recirculation is taken through an intake pipe (6) downstream of the catalyst, and preferably upstream of a filter (5b) for soot. The recirculated gases are passed through a cooler (7) upstream of the EGR valve (8). Good removal of soot and NOx is achieved even at low exhaust gas temperature.

Abstract: A particulate trap has a housing and a plurality of filters disposed within the housing. The particulate trap also has a plurality of dividers fluidly isolating one or more of the plurality of filters into filter divisions. The particulate trap has at least one inlet and at least one outlet individually associated with each filter division, and a valve assembly configured to selectively block a flow of exhaust air through each of the inlets.

Abstract: In an exhaust heat recovery system, electric power generation efficiency of a thermoelectric conversion element can be improved, and warming-up of a catalyst can be completed early, without using a complicated device. The exhaust heat recovery system according to the invention includes an exhaust pipe in which exhaust gas discharged from an internal combustion engine flows; a catalyst which purifies the exhaust gas; a heat recovery portion which is fitted to the exhaust pipe, and which recovers heat contained in the exhaust gas; a thermoelectric conversion element which generates electric power using thermoelectric conversion; and a heat pipe which connects the heat recovery portion to the thermoelectric conversion element, and which transfers the heat recovered in the heat recovery portion to the thermoelectric conversion element. An operation starting temperature of the heat pipe is set so as to be higher than an activation temperature of the catalyst.

Abstract: A secondary air pressure detecting apparatus includes a solenoid valve and a pressure sensor. The solenoid valve defines a secondary air passage that introduces secondary air from the air pump into the exhaust system of an engine. The solenoid valve opens and closes the secondary air passage. The pressure sensor is integrally mounted to the solenoid valve to detect pressure of secondary air in the solenoid valve. The solenoid valve includes a coil assembly and magnetic members. The coil assembly includes a solenoid coil that generates magnetic force when the solenoid coil is energized. The magnetic members construct a magnetic circuit with the solenoid coil. The magnetic circuit is arranged outside of the secondary air passage. The pressure sensor is arranged on an opposite side of the secondary air passage with respect to the magnetic circuit.

Abstract: An exhaust gas purification system for an internal combustion engine can quickly recover the exhaust gas purification ability of an exhaust gas purification device by increasing opportunities to release the SOx occluded in the exhaust gas purification device. In the exhaust gas purification system having the exhaust gas purification device having the property of occluding the SOx in the exhaust gas emitted from the internal combustion engine and collecting particulate matter contained in the exhaust gas, when the load of the internal combustion engine falls within a load range in which SOx poisoning recovery control can be executed, during the time when the particulate matter is oxidized and removed by collection ability regeneration control (S105), the collection ability regeneration control is interrupted and the SOx poisoning recovery control is executed (S106, S107).

Abstract: The invention relates to a method and an arrangement for monitoring the operability of a secondary air system of an internal combustion engine having an exhaust-gas system. The secondary air system includes a secondary air pump. In the method and arrangement, a signal is determined which characterizes the secondary air flow. In the method, at least one signal of at least one operating characteristic variable of the secondary air pump is determined during the determination of the signal characterizing the secondary air flow and a conclusion is drawn as to a fault in the secondary air system when the signal of the at least one operating characteristic variable lies outside of a pregiven interval. The at least one signal of at least one operating characteristic variable is determined in dependence upon the operating state of the engine. This signal is determined from a signal for the pump current of an electrically operated secondary air pump.

Abstract: An exhaust gas purification system including a catching reactor for attracting particulate matters in an exhaust gas from an engine by electrostatic force, a main exhaust path and an auxiliary exhaust path provided on the exit side of the catching reactor, a PM filter provided in the auxiliary exhaust path for filtrating and processing the exhaust gas, and a flow path control valve for selectively connecting the exit side of the catching reactor to the main exhaust path or the auxiliary exhaust path.

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: In a secondary air supply system, each of two branch portions of a secondary air supply pipe that is divided from a joint portion is provided with an air control valve, and the joint portion is provided with a pressure sensor and an auxiliary air control valve. The air control valves are opened at different timings such that pressure fluctuations in the joint portion upon opening of the firstly and the secondly opened air control valves are measured. An abnormality diagnosis is performed with respect to those two air control valves based on combinations of the aforementioned two pressure fluctuations.

Abstract: A reciprocating piston-type internal combustion engine includes an engine cylinder, an intake port, an intake runner providing a passage through which intake gas enters the cylinder through the intake port, an intake valve for opening and closing the intake port, and a first flap located in the intake runner upstream from the intake valve, arranged in series with the intake valve, and having first and second positional states that vary during each engine cycle. The first state opens the intake runner passage to permit intake gas to enter the cylinder through the intake port. The second state at least partially closes the intake runner passage to control the flow of gas exiting or entering the cylinder through the intake port.

Abstract: In one example, a system for an engine having an intake system and an exhaust system is described. The system comprises: an airflow sensor coupled to the intake system; an air pump having at least an inlet side and an outlet side, said inlet side having a first coupling to the intake system downstream of said airflow sensor, said outlet side having a second coupling to the exhaust system; and a controller coupled to the engine, said controller, during operation, identifying whether degradation has occurred to at least one of said first and second couplings, and providing an indication of said identified degradation. Various other examples are also disclosed.

Abstract: A valve assembly is adapted to be disposed in an automotive engine exhaust system at an outlet of an internal combustion engine. The assembly includes a valve body having an opening therethrough including an inlet portion and an outlet portion. A first valve and a second valve are disposed in the opening intermediate the inlet and outlet portions. The first and second valves have an open position and a closed position. The first valve blocks a first predetermined amount of the opening when in the closed position. The second valve blocks a second predetermined amount of the opening when in the closed position, with the second predetermined amount being less than the first predetermined amount. An actuator is connected to the first valve and the second valve and is operable to selectively move each of the valves between respective the open positions and the closed positions.

Abstract: An internal combustion engine is supplied with reformate from a hydrocarbon reformer at engine start-up and during engine warm-up. The reformate fuel mixture is fuel-lean at start-up to ensure that all the fuel is burned while the exhaust converter is thermally non-functional. Shortly after start-up, the mixture is changed to be fuel-rich, providing unburned reformate fuel in the exhaust stream. During start-up and warm-up, the output of an air pump is controllably divided between the reformer (primary air) and the engine exhaust system (secondary air). Unburned reformate from the engine and secondary air from the air pump ignite and thereby rapidly heat the converter. Gasoline or diesel fueling of the engine by fuel injection is preferably delayed until the engine and the converter both reach operating temperatures, whereupon the engine is fueled by fuel injection and further reforming is terminated.

Abstract: An engine control system and method maintains an optimum exhaust fuel to air ratio in an internal combustion engine. A secondary air injection (SAI) pressure is measured in an SAI system. The SAI pressure measurement is converted into an SAI flow value. A fuel compensation value is obtained based on the SAI flow value. Fuel delivery is compensated to the engine based on the fuel compensation value. In a second embodiment, the fuel compensation value is obtained based on the SAI pressure measurement. Fuel delivery is compensated to the engine based on the fuel compensation value. In a third embodiment, a primary flow value is calculated at an air intake of the engine. A fuel compensation value is calculated based on the SAI flow and primary flow values. Fuel delivery to the engine is compensated based on the fuel compensation value.

Abstract: An exhaust control apparatus applied to an internal combustion engine in which intake sides of a plurality of cylinder groups are connected to a common intake passage and exhaust sides thereof are connected to different exhaust passages, comprises an exhaust gas flow amount adjusting device for causing a flow amount of exhaust gas, which is discharged through each of the exhaust passages of the cylinder groups, to be changed, an exhaust gas flow amount difference estimating device for estimating a difference in an exhaust gas flow amount between the exhaust passages of the cylinder groups, and an exhaust gas flow amount control device for controlling the exhaust gas flow amount adjusting device so as to reduce the estimated difference in the exhaust gas flow amount.

Abstract: A method and system providing a vehicle condition detection means (38C) for detecting the stopped and traveling state of a vehicle, and when the vehicle condition detection means (38C) detects that the vehicle has stopped during operation of an exhaust gas temperature raising means (351C), closing an exhaust gas throttling valve (16) in addition to continuing the operation of the exhaust gas temperature raising means (351C), and subsequently, when the vehicle's traveling state is detected, opening the exhaust gas throttling valve (16) and continuing the operation of the exhaust gas temperature raising means (351C).

Abstract: A thermoelectric generating device has a thermoelectric element which utilizes an exhaust gas from an engine as a high temperature heat source and an engine coolant as a low temperature heat source in order to generate electricity. An introducing passage introduces a part of the exhaust gas passed through the thermoelectric element into an intake of the engine. An introducing valve opens and closes the introducing passage. A controller controls an opening degree of the introducing valve according to a load of the engine.

Abstract: An apparatus for posttreatment of exhaust gases of an internal combustion engine, using a reducing agent to be introduced into the exhaust gases, in particular a urea or a urea-and-water solution, having an improved mixing chamber into which stored reducing agent, via a reducing agent line, and compressed air via a compressed air line can be introduced to create a reducing agent-air mixture, and means for preventing a reverse flow of reducing agent or reducing agent-air mixture from the mixing chamber into the compressed air line are provided which have a spring-loaded sealing hose. This arrangement assures secure sealing off of an attachable compressed air system from the corrosive reducing agent.

Abstract: An exhaust system can comprise a NOx adsorber, a reformer disposed upstream of a NOx adsorber and in fluid communication with a fuel source, a first valve for controlling the introduction of the fluid to an exhaust conduit; and a particulate filter disposed upstream and in fluid communication with the NOx adsorber and downstream an in fluid communication with the reformer such that the first valve controls introduction of fluid to the exhaust conduit upstream of the particulate filter. The reformer can be designed to generate a fluid comprising sufficient thermal energy, hydrogen, and carbon monoxide. Optionally, the particulate filter can be designed to be regenerated by the thermal energy and to adsorb a sufficient amount of the thermal energy to reduce the temperature of a gas stream comprising the fluid from a first temperature of about 600° C. to about 1,000° C. to a second temperature of less than or equal to about 500° C.

Abstract: In the disclosed secondary air supply system, an on-off valve (13) is driven by the discharge pressure of an air pump (12). A diaphragm chamber (44) is arranged in the neighborhood of a discharge outlet (54), and a part of the discharge air flows directly into the diaphragm chamber (44). Thus, the on-off valve (13) is positively operated even at high places with low atmospheric pressure and has a fast open/close response. As an electromagnetic actuator is not used to drive the on-off valve (13), the voltage supplied to the air pump (12) (DC motor (29)) does not drop inconveniently, and at the same time, the cost is reduced. Further, the number of the lead wires (65) is reduced.

Abstract: In an electrical multi-purpose valve for supplying secondary air into an exhaust system of an internal combustion engine, in which a power-actuated closing member controls a valve orifice in a passage between an inlet from an air supply line and an outlet to the exhaust system, a non-return valve is arranged downstream of the closing body in the direction of the flow of the air through the valve between the non-return valve and the valve outlet, and baffle devices are provided which deflect exhaust gas entering the valve from the outlet at least once by an angle of about 90°.

Abstract: An exhaust emission purification device comprises a sulfur component holding agent arranged on the exhaust path of an internal combustion engine for holding a sulfur component, a NOx holding agent arranged downstream of the sulfur component holding agent in the exhaust gas for holding NOx and the sulfur components when the air-fuel ratio of the exhaust gas flowing thereinto is lean, and a reducing agent adding unit for adding a reducing agent to the exhaust gas flowing into the NOx holding agent. The concentration of the sulfur component contained in the reducing agent added by the reducing agent adding unit is lower than the concentration of at least the sulfur component contained in the fuel supplied to the combustion chamber of the internal combustion engine. Thus, the sulfur poisoning of the exhaust emission purifier can be avoided while at the same time reducing the fuel consumption rate.

Abstract: An automobile catalytic converter that utilizes the energy of the exothermic reactions that take place in the catalysis substrate to produce electrical energy with a thermoelectric generator. On vehicle cold start, the thermoelectric generator is used as a heat pump to heat the catalyst substrate to reduce the time to catalyst light-off. In this way, the catalytic converter comes up to operating temperature more rapidly, reducing the amount of pollutant emissions at vehicle start-up.

Abstract: In accordance with one embodiment of the present invention, a device for generating hydrogen from a water vapor containing exhaust is provided. The device comprises an exhaust diverter and a hydrogen generation section. The exhaust diverter is configured to divert a portion of the exhaust to the hydrogen generation section. The hydrogen generation section comprises an electrolysis unit defining a hermetically sealed void volume configured to accumulate and store hydrogen. The exhaust diverter may be placed in communication with a heat exchanger configured to increase a fractional relative humidity of the diverted exhaust by cooling the diverted exhaust. In accordance with 37 CFR 1.72(b), the purpose of this abstract is to enable the United States Patent and Trademark Office and the public generally to determine quickly from a cursory inspection the nature and gist of the technical disclosure. The abstract will not be used for interpreting the scope of the claims.

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 heated and insulated catalytic converter includes a heat storage device and a control system for maintaining an elevated temperature while the engine is not operating. The control system may also include control of flaps to allow cool air to circulate to prevent overheating and timers.

Abstract: An exhaust gas system for an internal combustion engine, in particular, of a motor vehicle has two mufflers through which the exhaust gas is able to flow in a parallel fashion. A switching unit makes it possible to selectively convey the exhaust gas flow of the internal combustion engine only or almost exclusively through the first muffler, or only or almost exclusively through the second muffler, or through both mufflers in a parallel fashion. The two mufflers are realized differently with respect to their muffling effect and/or flow resistance.

Abstract: The invention relates to a secondary air feeding apparatus and a method of detecting an abnormality in the apparatus capable of making a precise determination on abnormalities in components and detecting operational failures as well. According to one aspect of the invention, the opening-closing state of opening-closing means (ASV) is switched during the operation of an air pump, and abnormalities in respective components are detected on the basis of pressure values and pressure fluctuation values detected by a pressure sensor disposed between the air pump and the ASV before and after the switching of the opening-closing means.

Abstract: A method for checking the functionality of a water adsorber in the exhaust of an internal combustion engine is provided. A sensor measures the temperature of the exhaust gases downstream in the flow direction from the water adsorber, and the functionality of the water adsorber is judged based on the change over time in the rate of increase in the sensed temperature after the internal combustion engine has been started.

Abstract: Exhaust emission control apparatus and method for an internal combustion engine maintain a small amount of sulfur components contained in exhaust gas flowing out of a sulfur component retainer agent even if the amount of sulfur components retained by the agent becomes great. The exhaust emission control apparatus includes a NOx retainer agent and the sulfur component retainer agent. The apparatus performs a NOx releasing process of adjusting the air-fuel ratio of exhaust gas flowing into the sulfur component retainer agent so that the air-fuel ratio of exhaust gas flowing into the NOx retainer agent becomes substantially stoichiometric or rich of stoichiometry if NOx retained by the NOx retainer agent is to be released. The apparatus prohibits the air-fuel ratio of exhaust gas flowing into the sulfur component retainer agent from becoming substantially stoichiometric or rich of stoichiometry if the amount of the sulfur components retained by the agent is at least a first predetermined amount.

Abstract: An internal combustion engine emission control apparatus includes split passages that divide exhaust gas discharged from an internal combustion engine into a plurality of streams. Emission control catalysts are provided that individually divide the exhaust gas in the split passages, and remove a component present in the exhaust gas at a high removal rate if a temperature of exhaust gas that inflows via the split passages satisfies a predetermined temperature condition. A controller changes proportions of the amounts of flow of the exhaust gas into the split passages so that the predetermined temperature condition is satisfied in at least one split passage of the split passages. Therefore, the emission control can be performed in a broad range of changing temperatures of the exhaust gas.

Abstract: A diesel engine exhaust gas purifying device includes a first continuous regeneration type diesel particulate filter in the exhaust gas passage, a by-path by-passing a portion of the exhaust gas passage upstream of the first continuous regeneration type diesel particulate filter, a second continuous regeneration type diesel particulate filter in the by-path, a change-over valve in the exhaust gas passage between the ends of by-path, an exhaust gas temperature-elevating mechanism, an exhaust gas temperature region detecting mechanism, and a control mechanism for controlling the exhaust gas temperature-elevating mechanism and the change-over valve based on the exhaust gas temperature region.

Abstract: An oxidation promoting catalyst (42) which converts nitrogen monoxide in exhaust gas to nitrogen dioxide, and a diesel particulate filter (41) which traps soot in the exhaust gas, are installed in an exhaust gas passage of a diesel engine (1). A control unit (21) determines whether or not it is necessary to regenerate the filter based on the exhaust gas pressure detected by an exhaust gas pressure sensor (24), and when it is necessary to regenerate the filter, it increases the nitrogen monoxide in the exhaust gas by performing an advance correction of the fuel injection timing of a fuel injector (14) so as to promote generation of nitrogen dioxide by the oxidation promoting catalyst. The nitrogen dioxide decreases the combustion temperature of the soot trapped by the diesel particulate filter (41), and efficiently regenerates the filter.