Abstract: A water level measuring apparatus and a water level measuring method, in which a water level L0 of a liquid is read from a water level indicator secured to a liquid tank, and a filter value FLT is calculated by applying a filter with a time constant greater than one second to the water level L0, and the filter value FLT is output as a final water level L. Accordingly, even if the surface sloshes and the water level L0 fluctuates up and down, the water level L0 is smoothed by the filter. Hence there is little influence of the liquid sloshing, and the water level measurement accuracy can be improved.

Abstract: On the basis of a correlation between exhaust gas temperature detected by an exhaust gas temperature sensor and exhaust gas temperature estimated according to an engine operating condition, it is detected whether or not abnormality occurs in the exhaust gas temperature sensor. Namely, when a change characteristic of the detected exhaust gas temperature follows a change characteristic of the estimated exhaust gas temperature, it is determined that the exhaust gas temperature sensor is normal. On the other hand, when the change characteristic of the detected exhaust gas temperature does not follow that of the estimated exhaust gas temperature, it is determined that the exhaust gas temperature sensor is abnormal.

Abstract: An exhaust gas purification apparatus includes an NOx reduction catalytic converter disposed in an engine exhaust passage to reductively purify NOx in exhaust gas using ammonia or its precursor as a reducing agent, a first concentration sensor which detects an ammonia concentration in an exhaust gas moving on a downstream side of the NOx reduction catalytic converter, and a control unit which incorporates therein a computer. The control unit conducts calculation to estimate an ammonia concentration in the exhaust gas moving on the downstream side of the NOx reduction catalytic converter, and when a difference between the ammonia concentration detected by the first concentration sensor and the estimated ammonia concentration by the calculation becomes larger than a first predetermined value, determines that the NOx reduction catalytic converter is deteriorated.

Abstract: A concentration sensor for detecting a concentration of a liquid reducing agent through heat transfer characteristics between separate two points is provided in a storage tank for storing a liquid supplied to an NOx reduction catalyst. When the concentration read from the concentration sensor is 0% or less, the liquid is discriminated to be water, that is, it is utilized that when water is converted to the concentration of a liquid reducing agent, it is 0%, and it is also 0% even when the concentration is reduced by convection. When the concentration is greater than a predetermined value, it is discriminated that no liquid is present, since it is considered that the output of the sensor is abnormal because of the absence of a liquid in the tank. On the other hand, when the concentration is greater than 0% and less than a predetermined value, the liquid is discriminated to be the liquid reducing agent, provided that the concentration value may include an error.

Abstract: A discriminating apparatus of liquid reducing agent is disclosed, in which, based on concentration of liquid reducing agent which is measured at each predetermined time after starting of engine, discrimination is processed whether the storage tank is filled with dissimilar aqueous solution, the storage tank is normally filled with the liquid reducing agent, or the storage tank is empty. When the empty discrimination or the dissimilar aqueous solution discrimination is performed, it is judged whether or not the discrimination is adequate according to the liquid condition in the storage tank. When the empty or the dissimilar aqueous solution discrimination is adequate, the empty discrimination frequency or the dissimilar aqueous solution discrimination frequency is counted up. When the empty discrimination frequency and the dissimilar aqueous solution discrimination frequency become equal to or larger than the first predetermined frequency, the discrimination is upheld.

Abstract: Subject To enable an appropriate operation of an exhaust gas purifying apparatus which uses urea or the like as a reducing agent, and further, to enable the stable concentration detection and the stable supply of the reducing agent during the cold months and also to prevent the generation of ammonia series gas during the severe hot months. Means for solving the Subject An exhaust gas purifying apparatus in an engine 1 is for supplying the urea water in a storage tank 20 to a reduction catalyst 3 disposed in an exhaust system. In this exhaust gas purifying apparatus, a concentration detecting device 60 is disposed in the storage tank 20, and the detected concentration of the urea water is adopted as basic information for the supply control of the reducing agent.

Abstract: An engine exhaust emission purification apparatus for reducing and purifying NOx in the exhaust emission by using a liquid reducing agent having a temperature maintenance device for maintaining a temperature of at least a part of a liquid reducing agent supply system configured by an injection nozzle and piping of the injection nozzle at a temperature lower than a boiling point of a solvent of the liquid reducing agent or equal to or higher than a melting point of dissolved matter in which the liquid reducing agent existing in the liquid reducing agent supply system conducts heat exchange with the liquid reducing agent supply system thereby being maintained at a temperature lower than the boiling point of the solvent or equal to or higher than the melting point of the dissolved matter and resultantly, occurrence of precipitation of the dissolved matter due to evaporation of only the solvent in the liquid reducing agent supply system does not occur, and even if precipitation of the dissolved matter occurs, the

Abstract: On an upper surface of a container body, there are disposed at least a base portion of a concentration meter configured to detect the concentration of a liquid reducing agent based on a heat transmission characteristic between two spaced points, and a heat exchanger configured to permit the engine coolant to circulate therein and arranged to surround a detecting section of the concentration meter, which hangs from the base portion of the concentration meter via a supporting column thereof, to thereby perform the heat exchange with the liquid reducing agent, and also, a protector or an encasing element of substantially box shape is arranged to surround a lower portion of the heat exchanger and the detecting section of the concentration meter, and further, a visor is attached on the supporting column of the concentration meter, which is positioned above the protector by a predetermined interval.

Abstract: An engine C/U 51 detects an abnormality which has occurred in an engine, and outputs a signal that indicates the occurrence of this abnormality to an SCR-C/U 61. The SCR-C/U 61 increases and decreases the urea water injection quantity corresponding to the abnormality which has occurred. On the other hand, the SCR-CU 61 detects an abnormality that has occurred in the SCR device, and outputs a signal that indicates the occurrence of this abnormality to an engine C/U 51. The engine C/U 51 controls an engine part such as an EGR valve, to reduce the NOx emission amount.

Abstract: An engine exhaust emission purification apparatus for reducing and purifying NOx in the exhaust emission by using a liquid reducing agent having a temperature maintenance device for maintaining a temperature of at least a part of a liquid reducing agent supply system configured by an injection nozzle and piping of the injection nozzle at a temperature lower than a boiling point of a solvent of the liquid reducing agent or equal to or higher than a melting point of dissolved matter in which the liquid reducing agent existing in the liquid reducing agent supply system conducts heat exchange with the liquid reducing agent supply system thereby being maintained at a temperature lower than the boiling point of the solvent or equal to or higher than the melting point of the dissolved matter and resultantly, occurrence of precipitation of the dissolved matter due to evaporation of only the solvent in the liquid reducing agent supply system does not occur, and even If precipitation of the dissolved matter occurs, the

Abstract: A particulate filter 8 is disposed in an exhaust passage 7 of an internal combustion engine 1, and a reduction catalyst 9 is disposed downstream of the particulate filter 8. A bypass passage 12 for bypassing the reduction catalyst 9 and a flow path switching valve 13 which switches a flow path for the exhaust gas which has passed through the particulate filter 8 between the exhaust passage 7 and the bypass passage 12 are disposed. A control unit 301 controls the flow path switching valve 13 in association with a temperature Texh of the exhaust gas which has passed through the particulate filter 8.

Abstract: Provided in a catalyst system are: a first reaction part fitted with a first catalyst containing, as active constituents, at least, a complex oxide consisting of two or more oxides selected from among silica, alumina, titania, zirconia, and tungsten oxide, and a rare earth metal or transition metal (except Cu, Co, Ni, Mn, Cr, and V); and a second reaction part fitted with a second catalyst containing, as active constituents, at least, a noble metal and a silica-alumina type complex oxide.

Abstract: For preventing clogging in an injection nozzle for supplying a reducing agent to exhaust gas flow on an upstream side of a reducing catalyst and for improving the efficiency of NOx purification processing, the injection nozzle 14 has a tip end portion 18 provided with a ring shaped protruding ridge 19 disposed on an outer peripheral surface of an exhaust gas downstream side end portion of the tip end portion 18 that is arranged substantially in parallel with an exhaust gas flow direction A inside an exhaust pipe 13, the ring shaped protruding ridge 19 being provided with injection hole or holes 20 drilled outward from the central axis of the injection nozzle 14, so that the reducing agent is ejected on the exhaust gas upstream side of the reduction catalyst, from the injection holes 20.

Abstract: Each of a first and a second number of times is counted, in which the first number of times indicates a condition where a concentration of a liquid reducing agent indirectly measured based on a characteristic of heat transmission between two separated points is successively determined to be equal to or higher than an upper limit threshold for no agent, and the second number of times indicates a condition the concentration is successively determined to be equal to or lower than a lower limit threshold for different agent. When the former becomes equal to or larger than the predetermined value, determination is made that no liquid reducing agent remains. When, the latter becomes equal to or larger than the predetermined value, determination is made that the liquid reducing agent is a solution of a different kind. When the former and the latter is less than the predetermined value, determination is made that correct liquid reducing agent remains.

Abstract: A liquid reducing agent of a necessary amount according to an engine operating condition is injection-supplied from a nozzle having an injection hole opening to inside an exhaust gas passage, positioned on an exhaust gas upstream side of a nitrogen oxide reduction catalyst. On the other hand, when an injection flow rate of the liquid reducing agent becomes zero, compressed air stored in a purge air tank is supplied into the nozzle for a predetermined time. Thus, the liquid reducing agent remaining in the nozzle is forcibly discharged by the compressed air, and hence even if the nozzle is at a high temperature due to the exhaust heat, a situation where reducing agent constituents are deposited does not occur, and clogging of the inside of the nozzle can be prevented.

Abstract: When a concentration measured by a sensor is lower than a predetermined threshold, it is judged that a liquid is any different type of aqueous solution, and also, it is judged whether or not the different type discrimination is adequate. When the discrimination is adequate, the number of different type discriminating times is counted up based on a predetermined counted value, and when the number thereof is equal to or larger than a determination threshold, the different type discrimination is determined. At this time, at least one of the predetermined counted value and the determination threshold is dynamically set based on a liquid level of a reducing agent tank, so that the counting and/or the different type discriminating determination is performed considering convection which is changed according to a level change to thereby discriminate with high precision whether or not the liquid is the different type of aqueous solution.

Abstract: The flow of exhaust gas flowing through the SCR muffler becomes good, thus improving the efficiency of purging nitrogen oxide (NOx) contained in exhaust gas. Further, vibrations that are caused by vibrations of the vehicle, exhaust gas, and the like, to which a reducing agent, etc., supplying nozzle is subject, are suppressed or reduced, thus improving the efficiency of an SCR catalyst purging nitrogen oxide (NOx) and the durability of the reducing agent, etc., supplying nozzle. The SCR muffler comprises an SCR catalyst 1 for selectively reducing and purging nitrogen oxide (NOx) contained in exhaust gas; an exhaust pipe 2 that allows the exhaust gas to flow into the SCR catalyst; and a reducing agent, etc., supplying means 3 that supplies a reducing agent or a reducing agent precursor to the exhaust gas. A plate 4 having air holes 5 which disperse and make a flow of the exhaust gas uniform is provided downstream of the reducing agent, etc., supplying means and upstream of the SCR catalyst.

Abstract: A water level measuring apparatus and a water level measuring method, in which a water level L0 of a liquid is read from a water level indicator secured to a liquid tank, and a filter value FLT is calculated by applying a filter with a time constant greater than one second to the water level L0. Furthermore when the filter value FLT is less than a minimum value Min, the minimum value Min is sequentially updated with the filter value FLT. Then the minimum value Min is output as the final water level L. Accordingly, even if the surface sloshes and the water level L0 fluctuates up and down, by adopting the minimum value that utilizes the characteristic of the surface fluctuations, as the final water level L, there is little influence of the liquid sloshing, and the water level measurement accuracy can be improved.

Abstract: In order to suppress deposition of constituent of a reducing agent (dissolved matter) in an exhaust passage of an engine enhancing an elimination rate of NOx even when temperature of an exhaust emission from the engine is low, an exhaust emission purifying apparatus is provided with an electro-generative-heat carrier provided on an upstream side of an injection nozzle that supplies the reducing agent into the exhaust emission on upstream side of a reduction catalyst in an exhaust pipe, the exhaust emission being heated to a temperature equal to or higher than a melting point of the dissolved matter whereby deposition of the dissolved matter on an inner wall surface of the exhaust pipe is suppressed to effectively use the supplied reducing agent for catalytic reduction reaction, even when the exhaust emission temperature is lower than the melting point of the dissolved matter of the reducing agent.

Abstract: An engine exhaust emission purification apparatus for reducing and purifying NOx in the exhaust emission by using a liquid reducing agent having a temperature maintenance device for maintaining a temperature of at least a part of a liquid reducing agent supply system configured by an injection nozzle and piping of the injection nozzle at a temperature lower than a boiling point of a solvent of the liquid reducing agent or equal to or higher than a melting point of dissolved matter in which the liquid reducing agent existing in the liquid reducing agent supply system conducts heat exchange with the liquid reducing agent supply system thereby being maintained at a temperature lower than the boiling point of the solvent or equal to or higher than the melting point of the dissolved matter and resultantly, occurrence of precipitation of the dissolved matter due to evaporation of only the solvent in the liquid reducing agent supply system does not occur, and even if precipitation of the dissolved matter occurs, the