Abstract: A burner for exhaust gas purification devices, comprising a base section, a first pipe section, and a second pipe section. The first pipe section has abase end section, a tip section, a combustion chamber, and a discharge port from which combusted gas is discharged. The base end section and the tip section are fixed to the base section. The second pipe section has a base end section and a tip section, and said base end and tip sections are fixed to the base section. The first pipe section also comprises an expansion/contraction section capable of expanding and contracting in a direction parallel to the central axis. The first pipe section and the second pipe section mutually overlap in the radial direction so as to form a multilayer tube structure.

Abstract: This burner has: a flame stabilizer formed in a tubular shape; a fuel supply unit that supplies fuel within the flame stabilizer; an air supply passage that includes a heater unit for heating air and that supplies air heated by the heater unit into the flame stabilizer; and an ignition unit that ignites the air-fuel mixture of combustion air and fuel within the flame stabilizer.

Abstract: This burner is disposed at the upstream side of a DPF and raises the temperature of exhaust by combusting an air-fuel mixture of air and fuel in a combustion region within a flame holder. The burner is provided with: an upstream-side cover enclosing the peripheral wall of the flame holder; and a partition wall that partitions the gap between the flame holder and the upstream-side cover into a prior-stage exhaust chamber and a latter-state exhaust chamber. An exhaust tube through which exhaust from an engine flows is connected to the upstream-side cover; a through hole that interconnects the prior-stage exhaust chamber and the latter-stage exhaust chamber is formed at the partition wall; exhaust flows in from the exhaust tube at the prior-stage exhaust chamber; and exhaust flows in from the prior-stage exhaust chamber through the through hole to the latter-stage exhaust chamber.

Abstract: A burner for an exhaust purifying device includes a tube, an air supply port for supplying air for combustion into the tube, a fuel supply port for supplying fuel into the tube, and an ignition portion. The tube includes a premixing chamber for mixing air for combustion and fuel to generate a pre-mixed air-fuel mixture, a combustion chamber for combusting the pre-mixed air-fuel mixture to generate post-combustion gas, and a discharge port for discharging the post-combustion gas. The ignition portion ignites the pre-mixed air-fuel mixture in the combustion chamber. The tube further includes a swirling flow generation unit arranged upstream of the premixing chamber for generating a swirling flow of which the center direction corresponds to a fuel injection direction and a diffusion unit arranged downstream of the swirling flow generation unit in the premixing chamber for diffusing the fuel incorporated in the swirling flow.

Abstract: An engine exhaust purification device includes a filter, a burner, and a control unit. The filter is arranged in an engine exhaust pipe. The burner burns fuel injected from a fuel injection nozzle and heats exhaust to increase the temperature of the filter at an upstream side of the filter in the exhaust pipe. A period including a single fuel injection period and a single injection stop period is set as a single injection cycle. The fuel injection period is a period injecting fuel a number of times at a predetermined frequency. The injection stop period is a variable period that stops fuel injection. The control unit controls the fuel injection nozzle so that the fuel injection nozzle injects the fuel according to the injection cycle. The control unit is configured to lengthen the injection stop period as the temperature of the filter increases.

Abstract: A burner used in an exhaust purifying device that purifies exhaust in an exhaust pipe of a diesel engine is provided with a tubular flame stabilizer including an ejection port from which fluid generated through combustion is ejected. The flame stabilizer includes a connecting passage, which connects the interior of the flame stabilizer and the exterior of the flame stabilizer. A recirculation unit is arranged at an outer side of the flame stabilizer. The recirculation unit includes a flow receiving portion that receives the fluid ejected from the ejection port, and an outer guiding portion that guides the fluid received by the flow receiving portion to the connecting passage.

Abstract: Disclosed is a method for warming an after-treatment system in which a burner 14 is arranged upstream of a particulate filter 12 (exhaust purifying member) incorporated in an exhaust pipe 11 and the particulate filter 12 is adapted to be heated by combustion with the burner 14. On condition that an ambient temperature surrounding the burner 14 is below a predetermined temperature, the energization is conducted to an electromagnetic valve-type injector 15 serving for fuel spray of the burner 14 with the fuel supply being stopped. The energization brings about Joule heat generated in an electromagnetic coil inside the injector 15 to make the warming.

Abstract: A fuel spray nozzle 16 has a cylindrical spray block 18 with an inner air passage 17 for flow of nebulizing air 4? and a fuel injection valve 20 for injection of fuel intermediately of the inner air passage 17 in the spray block 18 at a flow rate adjusted by duty control. The nebulizing air is introduced into the spray block 18 through a base end of the block at a flow velocity of 9 m/s or more and blown out of an injection port 21 at a tip end of the block.

Abstract: Injection nozzle 7 and electrode rods 8 and 9 (ignitor) are surrounded by double-cylinder flame stabilizer 10. Toroidal blocking plate 13 closes between inner and outer cylinders 11 and 12 of the stabilizer at its distal end whose proximal end is connected with line 15 for introducing combustion air 14 to between the cylinders. Inflow holes 16 are formed throughout the inner cylinder at its proximal end. Peripheral fins 17 are formed peripherally on the inner cylinder radially inwardly through cutting and bending-up at positions shifted from the inflow holes toward the distal end of the inner cylinder such that combustion air is introduced from circumferentially to form swirling flow inside the inner cylinder. End fins 18 are formed on the blocking plate in fuel injection direction through cutting and bending-up such that combustion air is discharged circumferentially to form swirling flow around flame 21.

Abstract: Enabled is reliable detection of abnormality in a NOx emission control system. Disclosed is a method for detecting abnormality in an exhaust emission control device with a reducing agent (urea water 17) being added to selective reduction catalyst 10 incorporated in an exhaust pipe 9 so as to reduce and purify NOx. Temperature of the catalyst during an operation period is monitored to record a cumulative time for each of temperature zones. On the basis of the recorded cumulative time for each of the temperature zones, a deterioration coefficient of NOx reduction performance is determined for each of the temperature zones. A standard NOx reduction ratio predetermined for each of the temperature zones is multiplied by the determined deterioration coefficient for each of the temperature zones to update the standard NOx reduction ratio.

Abstract: Excessive generation NO2 by oxidation catalyst arrangement upstream of a selective reduction catalyst is suppressed to prevent falling of NOx reduction rate. A selective reduction catalyst 4 capable of selectively reacting NOx with ammonia even in the presence of oxygen is incorporated in an exhaust pipe 3 from an engine 1. A pair of oxidation catalysts 5A and 5B are arranged in parallel with each other and upstream of the selective reduction catalyst. In an operation condition with low exhaust temperature, amounts of the exhaust gas 2 distributed to the oxidation catalysts 5A and 5B are adjusted so as to make NO/NO2 ratio in the exhaust gas 2 to about 1-1.5.

Abstract: Urea water is added to a catalyst in an exhaust pipe for purification. A first-order lag response model corresponding to the exhaust temperature upstream of the catalyst estimates catalyst temperature for each of divided cells of the catalyst. Cell volumes for each of temperature zones are summed on the basis of the estimated temperatures for the cells. The summation for each temperature zone is divided by the whole catalyst volume to determine temperature distribution volume ratio. The ratio for each of the temperature zones is multiplied by a reference injection amount of the urea water determined in consideration to a current engine operation status on the assumption that the catalyst temperatures are all within the temperature zone. The calculated values for the respective temperature zone are summed into a directive injection amount of the urea water.

Abstract: When urea water U is injected by an addition nozzle 7 upstream of NOx reduction catalyst 6 incorporated in an exhaust passage 5 of a diesel engine 1 so as to reduce and purify NOx in exhaust G, both a value measured by a NOx concentration sensor 9 upstream of the nozzle 7 and a value measured by a NOx concentration sensor 12 downstream of the catalyst 6 are corrected by using a primary response model depending upon a flow rate and a temperature of exhaust G. The NOx reduction ratio is obtained on the basis of these corrected NOx concentration values. Rectified are time lag of measuring of a value by the downstream NOx concentration sensor 12 from measuring of a value by the upstream NOx concentration sensor 9 in a case of the exhaust G having a lower flow rate, and error due to lowering of NOx reduction processing speed in a case of the exhaust having a lower temperature.

Abstract: An exhaust emission control device with a plasma generator received in a filter casing incorporated in an exhaust pipe for capturing particulates and capable of conducting electric discharge so as to generate plasma in the exhaust gas at a capturing place and with a power supply for impressing voltage on the plasma generator. The plasma generator is unitized and arranged in plurality. A control switch is provided for sequential changeover of the connection of the power supply to the plural units of the plasma generator. A processing capability comparable to a single, large-sized plasma generator is obtained while increase in size of the power supply is prevented.

Abstract: Enabled is reliable detection of abnormality in a NOx emission control system. Disclosed is a method for detecting abnormality in an exhaust emission control device with a reducing agent (urea water 17) being added to selective reduction catalyst 10 incorporated in an exhaust pipe 9 so as to reduce and purify NOx. Temperature of the catalyst during an operation period is monitored to record a cumulative time for each of temperature zones. On the basis of the recorded cumulative time for each of the temperature zones, a deterioration coefficient of NOx reduction performance is determined for each of the temperature zones. A standard NOx reduction ratio predetermined for each of the temperature zones is multiplied by the determined deterioration coefficient for each of the temperature zones to update the standard NOx reduction ratio.

Abstract: Excessive generation NO2 by oxidation catalyst arrangement upstream of a selective reduction catalyst is suppressed to prevent falling of NOx reduction rate. A selective reduction catalyst 4 capable of selectively reacting NOx with ammonia even in the presence of oxygen is incorporated in an exhaust pipe 3 from an engine 1. A pair of oxidation catalysts 5A and 5B are arranged in parallel with each other and upstream of the selective reduction catalyst. In an operation condition with low exhaust temperature, amounts of the exhaust gas 2 distributed to the oxidation catalysts 5A and 5B are adjusted so as to make NO/NO2 ratio in the exhaust gas 2 to about 1-1.5.

Abstract: An injection amount of a reducing agent such as urea water is properly and adequately controlled to keep a NOx reduction ratio as high as possible. Disclosed is a method for controlling an exhaust emission control device wherein urea water 17 (reducing agent) is added to selective reduction catalyst 10 incorporated in an exhaust pipe 9 so as to reduce and purify NOx. A first-order lag response model corresponding to the exhaust temperature upstream of the catalyst 10 is used to estimate catalyst temperature for each of cells into which the catalyst is minutely divided. Cell volumes for each of temperature zones are summed up on the basis of the estimated temperatures for the cells. The cell volume summation for each of the temperature zones is divided by the whole volume of the catalyst to determine temperature distribution volume ratio.

Abstract: When urea water U is injected by an addition nozzle 7 upstream of NOx reduction catalyst 6 incorporated in an exhaust passage 5 of a diesel engine 1 so as to reduce and purify NOx in exhaust G, both a value measured by a NOx concentration sensor 9 upstream of the nozzle 7 and a value measured by a NOx concentration sensor 12 downstream of the catalyst 6 are corrected by using a primary response model depending upon a flow rate and a temperature of exhaust G. The NOx reduction ratio is obtained on the basis of these corrected NOx concentration values. Rectified are time lag of measuring of a value by the downstream NOx concentration sensor 12 from measuring of a value by the upstream NOx concentration sensor 9 in a case of the exhaust G having a lower flow rate, and error due to lowering of NOx reduction processing speed in a case of the exhaust having a lower temperature.

Abstract: When urea water U is injected by an addition nozzle 7 upstream of a NOx reduction catalyst 6 incorporated in the passage 5 so as to reduce and purify NOx in exhaust gas G, a target adsorption amount curve is set by shifting to lower temperature side a saturated adsorption amount curve of ammonia to the catalyst. A target adsorption amount of the reducing agent corresponding to the catalyst temperature is calculated and an actual adsorption amount of the reducing agent to the catalyst is determined. The amount of the urea water U to be added upstream of the catalyst is reduced when the actual adsorption amount reaches the target adsorption amount, and is increased when the actual adsorption amount is lower than the target adsorption amount. Thus, the adsorption amount of ammonia is secured while preventing ammonia from adsorbing so as to save the urea water U.