Abstract: The present disclosure relates to an exhaust gas aftertreatment system and method for controlling same. The exhaust gas aftertreatment system comprises: a reductant dosing device; a selective catalytic reduction device arranged downstream of the reductant dosing device; an ammonia slip catalyst arranged downstream of the SCR device; a feedback NOx sensor arranged downstream of the SCR device and upstream of the ammonia slip catalyst; a tailpipe NOx sensor arranged downstream of the ammonia slip catalyst; and a control device configured for: providing an initial dosing of reductant from the reductant dosing device; obtaining a feedback signal from the feedback NOx sensor and a tailpipe NOx signal from the tailpipe NOx sensor; and adjusting the dosing of reductant until the feedback signal exceeds the tailpipe NOx signal by a value within a predetermined positive interval.

Abstract: Disclosed is a method for use in a process of selective catalytic reduction (SCR) after-treatment of an exhaust gas of an exhaust gas stream, where the process comprises the reduction of nitrogen oxides of the exhaust gas stream through the use of a reducing agent derived from an additive. The disclosed method comprises: defining an integrand to be the difference between the rate of injection of the additive and the rate of evaporation of the additive to the reducing agent multiplied by a coefficient (s), wherein the value of the coefficient (s) is between zero and one; producing an integral controller output proportional to the integral of the integrand with time; requesting a countermeasure based on the integral controller output to counteract solid deposits derived from the additive.

Abstract: Disclosed is a method for use in a process of selective catalytic reduction (SCR) after-treatment of an exhaust gas of an exhaust gas stream, where the process comprises the reduction of nitrogen oxides of the exhaust gas stream through the use of a reducing agent derived from an additive. The disclosed method comprises: defining an integrand to be the difference between the rate of injection of the additive and the rate of evaporation of the additive to the reducing agent multiplied by a coefficient (s), wherein the value of the coefficient (s) is between zero and one; producing an integral controller output proportional to the integral of the integrand with time; requesting a countermeasure based on the integral controller output to counteract solid deposits derived from the additive.

Abstract: The present disclosure relates to an exhaust gas aftertreatment system and method for controlling same. The exhaust gas aftertreatment system comprises: a reductant dosing device; a selective catalytic reduction device arranged downstream of the reductant dosing device; an ammonia slip catalyst arranged downstream of the SCR device; a feedback NOx sensor arranged downstream of the SCR device and upstream of the ammonia slip catalyst; a tailpipe NOx sensor arranged downstream of the ammonia slip catalyst; and a control device configured for: providing an initial dosing of reductant from the reductant dosing device; obtaining a feedback signal from the feedback NOx sensor and a tailpipe NOx signal from the tailpipe NOx sensor; and adjusting the dosing of reductant until the feedback signal exceeds the tailpipe NOx signal by a value within a predetermined positive interval.

Abstract: Disclosed is a method for diagnosing functionality of dosing units of a fluid dosing system comprising at least two dosing units, a tank unit for holding a fluid, and a pump unit for pressurizing the fluid for the dosing units. The method comprises determining a first hydraulic stiffness value on the basis of first pressure variations and determining a second hydraulic stiffness value on the basis of said second pressure variations. The first hydraulic stiffness value and second hydraulic stiffness value are compared. In a case where the first hydraulic stiffness value and second hydraulic stiffness value differ to a certain extent, concluding that malfunction of at least one of said dosing units is at hand, and in a case where the first hydraulic stiffness value and the second hydraulic stiffness value do not differ to said certain extent, concluding that the first and second dosing units function as intended.

Abstract: Disclosed is a method for control of dosage of a reducing agent into an exhaust stream, which includes: determining at least one sensor signal SNOx from at least one nitrogen oxides NOx sensor arranged downstream of at least one of the one or more reduction catalysts as at least one sensor correction value SNOx_corr, respectively, if: 1) the engine rotates without fuel supply; 2) an exhaust mass flow M?exh is greater than an exhaust mass flow threshold M?exh_th; M?exh>M?exh_th; and 3) the sensor signal SNOx has had a value smaller than a sensor signal threshold SNOx_th; SNOx<SNOx_th; during at least a predetermined time period Tcon; determining at least one adjusted sensor signal SNOx_adj based on the at least one sensor signal SNOx and the at least one sensor correction value SNOx_corr, respectively; and controlling the dosage of the reducing agent based on the at least one adjusted sensor signal SNOx_adj.

Abstract: Disclosed is a method for control of dosage of a reducing agent into an exhaust stream, which includes: determining at least one sensor signal SNOx from at least one nitrogen oxides NOx sensor arranged downstream of at least one of the one or more reduction catalysts as at least one sensor correction value SNOx_corr, respectively, if: 1) the engine rotates without fuel supply; 2) an exhaust mass flow M?exh is greater than an exhaust mass flow threshold M?exh_th; M?exh>M?exh_th; and 3) the sensor signal SNOx has had a value smaller than a sensor signal threshold SNOx_th; SNOx<SNOx_th; during at least a predetermined time period Tcon; determining at least one adjusted sensor signal SNOx_adj based on the at least one sensor signal SNOx and the at least one sensor correction value SNOx_corr, respectively; and controlling the dosage of the reducing agent based on the at least one adjusted sensor signal SNOx_adj.

Abstract: Disclosed is a method for diagnosing functionality of dosing units of a fluid dosing system comprising at least two dosing units, a tank unit for holding a fluid, and a pump unit for pressurizing the fluid for the dosing units. The method comprises determining a first hydraulic stiffness value on the basis of first pressure variations and determining a second hydraulic stiffness value on the basis of said second pressure variations. The first hydraulic stiffness value and second hydraulic stiffness value are compared. In a case where the first hydraulic stiffness value and second hydraulic stiffness value differ to a certain extent, concluding that malfunction of at least one of said dosing units is at hand, and in a case where the first hydraulic stiffness value and the second hydraulic stiffness value do not differ to said certain extent, concluding that the first and second dosing units function as intended.

Abstract: The present invention relates to a method for determining when to correct supply of additive to an exhaust gas stream resulting from combustion in at least one combustion chamber, wherein the additive is arranged for reduction of at least one substance resulting from said combustion by supplying the additive to an exhaust gas stream resulting from said combustion. The quantity of additive being supplied is subjectable to correction, and a sensor is subjected to the exhaust gas stream and arranged to measure occurrence of said at least one substance. The method comprises: by means of sensor signals from said sensor, determining a level of occurrence of said first substance in said exhaust gas stream, and determining when to correct said supply of additive on the basis of said occurrence of said first substance in said exhaust gas stream.

Abstract: The present invention concerns a method in connection with the supplying of a first additive for treating an exhaust gas stream resulting from combustion in a combustion engine, wherein said first additive is supplied to said exhaust gas stream, and wherein said first additive is utilized for the reduction of at least a first substance (such as NOx) present in said exhaust gas stream, wherein the method comprises: estimation of a reduction of said first substance based on a first measurement of a presence of said first substance in said exhaust gas stream downstream of said supply of said first additive, and a second measurement of a presence of said first substance in said exhaust gas stream upstream of said supply of additive, comparison of said estimated reduction to a first reduction, and correction of the estimation of said second measurement of said first substance based on said comparison.

Abstract: The present invention relates to a method for determining when to correct supply of additive to an exhaust gas stream resulting from combustion in at least one combustion chamber, wherein the additive is arranged for reduction of at least one substance resulting from said combustion by supplying the additive to an exhaust gas stream resulting from said combustion. The quantity of additive being supplied is subjectable to correction, and a sensor is subjected to the exhaust gas stream and arranged to measure occurrence of said at least one substance. The method comprises: by means of sensor signals from said sensor, determining a level of occurrence of said first substance in said exhaust gas stream, and determining when to correct said supply of additive on the basis of said occurrence of said first substance in said exhaust gas stream.

Abstract: The present invention concerns a method in connection with the supplying of a first additive for treating an exhaust gas stream resulting from combustion in a combustion engine, wherein said first additive is supplied to said exhaust gas stream, and wherein said first additive is utilized for the reduction of at least a first substance (such as NOx) present in said exhaust gas stream, wherein the method comprises: estimation of a reduction of said first substance based on a first measurement of a presence of said first substance in said exhaust gas stream downstream of said supply of said first additive, and a second measurement of a presence of said first substance in said exhaust gas stream upstream of said supply of additive, comparison of said estimated reduction to a first reduction, and correction of the estimation of said second measurement of said first substance based on said comparison.

Abstract: A rock drill bit for percussive drilling comprising a bit head configured to be attached at an end of a drill element of a drilling assembly and having a diameter larger than that of a said drill element. The bit head has at a front end as seen in the intended drilling direction a generally frusto-conical shape defined by a substantially circumferential ring provided with a plurality of gauge buttons distributed along the extension of the ring for engaging material to be crushed. A central flush channel extends through the bit head and has at least one flushing hole opening at said front end to conduct flushing medium to said front end. At least one peripheral flushing hole of said at least one flushing hole opening at said front end opens in said substantially circumferential ring. At least two peripheral flushing holes open in said substantially circumferential ring.

Abstract: A rock drill bit for percussive drilling comprising a bit head configured to be attached at an end of a drill element of a drilling assembly and having a diameter larger than that of a said drill element. The bit head has at a front end as seen in the intended drilling direction a generally frusto-conical shape defined by a substantially circumferential ring provided with a plurality of gauge buttons distributed along the extension of the ring for engaging material to be crushed. A central flush channel extends through the bit head and has at least one flushing hole opening at said front end to conduct flushing medium to said front end. At least one peripheral flushing hole of said at least one flushing hole opening at said front end opens in said substantially circumferential ring. At least two peripheral flushing holes open in said substantially circumferential ring.

Abstract: The present invention relates to a drill bit and a single pass drilling apparatus. The one-piece drill bit has a connection portion, adapted to be rigidly connected to a drill steel, a pilot part and a reamer part. The pilot part has first rock machining means. The reamer part has a first center line and second rock machining means. The second rock machining means is provided axially between said connection portion and said first rock machining means and to one side of the pilot part. The drill bit has a rotational direction. A side of the pilot part facing away from the reamer part is provided with a wear resistant means. The wear resistant means is integral with the first rock machining means.

Abstract: A button bit is disclosed of the type that is rotatable in a predetermined direction of rotation (R) around a centre axis (C) and includes a number of spaced-apart peripheral buttons, which protrude forward from a front end surface to which an envelope surface connects having a rotationally symmetrical shape, the individual peripheral button being tilted partly in relation to the centre axis (C) of the drill bit, partly in the forward direction of rotation (R) in relation to the surface from which the button protrudes. The hole for the individual peripheral button mouths in a countersunk entering surface which is planar, ring-shaped and extends perpendicularly to the centre axis (C1) of the hole. By tipping the button in the forward direction of rotation, the same will operate aggressively and efficiently. Also, the peripheral button may be mounted in accurate drilled apertures which are simple to provide, despite the complex space geometry predicament.

Abstract: A male portion for percussive rock drilling includes sections of reduced cross-sectional area. At least one thread for percussive rock drilling is provided at an end of the male portion. The end of the male portion comprises an abutment surface for the transfer of impact waves. The length of the portion is defined as the length of an imaginary cylinder from a plane of the impact surface to a point where the plane ceases to contact a crest of the thread, wherein the length divided by the external diameter of the cylinder lies within a range of 1–2.

Abstract: A male portion for percussive rock drilling includes sections of reduced cross-sectional area. At least one thread for percussive rock drilling is provided at an end of the male portion. The end of the male portion comprises an abutment surface for the transfer of impact waves. The length of the portion is defined as the length of an imaginary cylinder from a plane of the impact surface to a point where the plane ceases to contact a crest of the thread, wherein the length divided by the external diameter of the cylinder lies within a range of 1-2.