JP2006052696A - Gas-fuel engine system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To estimate exactly the amount of sulfur component supplied to a catalytic device. <P>SOLUTION: A gas-fuel engine system comprises an odor sensor 16 provided in a fuel-supply channel to a gas-fuel engine 1 provided with a NSR catalyst 27 on the exhaust side, a buildup amount-estimating means for estimating a buildup amount of SOx in the NSR catalyst 27 on the basis of a detection value of the odorant sensor 16, and a poisoning-recovery controller for carrying out a SOx poisoning recovering control for the exhaust-gas purification catalyst when the amount of built-up SOx exceeds a predetermined threshold. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a gas fuel engine system that can use a gas fuel containing an odorant, and particularly relates to a gas fuel engine system in which processing of a sulfur component contained in the odorant is considered.

  In recent years, various gas fuel engines have been proposed in order to use gas fuels such as CNG (Compressed Natural Gas) and LPG (Liquid Petrol Gas) as fuel for internal combustion engines for automobiles. .

  In many cases, an odorant is added to the gas fuel used in such a gas fuel engine as a measure against gas leakage. However, when gas fuel containing an odorant is supplied to an engine equipped with an exhaust gas purification catalyst, deterioration of the exhaust gas purification catalyst is promoted by sulfur poisoning caused by sulfur components contained in the odorant. There is a problem that.

As a technique for estimating the amount of sulfur poisoning of the NOx absorption catalyst, Patent Document 1 discloses that an SOx (sulfur oxide) sensor using a solid electrolyte is provided in an engine exhaust system, and sulfur is integrated by integration based on the detected sulfur concentration. An apparatus for calculating the poisoning amount is disclosed. In Patent Document 1, the sulfur component is removed from the NOx absorption catalyst by enriching the air-fuel ratio when the catalyst exceeds a predetermined temperature in accordance with the calculated poisoning amount.
JP 2000-45753 A

  However, in the apparatus of Patent Document 1, since the SOx sensor is provided in the exhaust system, the measurement is easily affected by the exhaust heat, and there is a limit to the improvement in measurement accuracy.

  Accordingly, an object of the present invention is to provide means that can more accurately estimate the amount of the sulfur component supplied to the catalyst device.

  According to a first aspect of the present invention, there is provided a sulfur component detection means provided in a fuel supply path to a gas fuel engine having an exhaust gas purification catalyst on the exhaust side, and the exhaust gas purification based on a detection value of the sulfur component detection means. And a poisoning recovery control for performing SOx poisoning recovery control on the exhaust gas purifying catalyst when the estimated SOx deposition amount exceeds a predetermined threshold value. A gas fuel engine system.

  In the first aspect of the present invention, since the sulfur component detection means is provided in the fuel supply path to the gas fuel engine, the measurement is not influenced by the exhaust heat, and therefore the amount of the sulfur component supplied to the catalyst device is more accurately determined. Can be estimated. The gas fuel engine system referred to in the present invention includes not only a gas fuel used as a drive source but also a system using another drive source such as gasoline in combination with the gas fuel.

  A second aspect of the present invention is the gas fuel engine system according to claim 1, wherein the sulfur component detection means is an odor sensor.

  In the second aspect of the present invention, since the odor sensor is used as the sulfur component detection means, the measurement can be performed with particularly high accuracy.

  According to a third aspect of the present invention, there is provided the gas fuel engine system according to claim 1 or 2, wherein an odorant is provided from the gas fuel provided in the fuel supply path and upstream of the sulfur component detection means. The gas fuel engine system further comprises: an adsorbing unit that adsorbs; and a deterioration state output unit that outputs a deterioration state of the adsorbing unit based on a detection value of the sulfur component detecting unit.

  In the third aspect of the present invention, since the odorant can be adsorbed and removed from the gas fuel by the adsorbing means provided in the fuel supply path, and the adsorbing means is provided upstream of the sulfur component detecting means. By utilizing the detection value of the detection means, it is possible to detect the deterioration state of the adsorption means. Further, since the deterioration state of the suction means is output by the deterioration state output means, the user can know the deterioration state of the suction means by this output.

  A fourth aspect of the present invention is the gas fuel engine system according to claim 3, wherein a plurality of the adsorbing means are provided in parallel, and switching is performed for selectively supplying gas fuel to each of the adsorbing means. The gas fuel engine system is characterized in that means are provided in the fuel supply path.

  In the fourth aspect of the present invention, the gas fuel can be selectively supplied to each of the plurality of adsorbing means provided in parallel by the switching means provided in the fuel supply path. By switching to the means, the sulfur component in the gas fuel can be continuously removed.

  5th this invention is the gas fuel engine system of Claim 1 or 2, Comprising: It is provided in the said fuel supply path | route and upstream from the said sulfur component detection means, and an odorant is supplied from gas fuel. A gas comprising: an adsorbing means for adsorbing; a heating means for heating the adsorbing means; and a desorption control means for controlling the heating means to desorb the odorant from the adsorbing means. It is a fuel engine system.

  In the fifth aspect of the present invention, since the desorption control unit controls the heating unit that heats the adsorption unit and desorbs the odorant from the adsorption unit, the use period can be extended by regeneration of the adsorption unit.

  The heating means in the fifth aspect of the present invention is preferably an electric heater as in the sixth aspect of the present invention or an exhaust heat utilizing heater as in the seventh aspect of the present invention.

  An eighth aspect of the present invention is the gas fuel engine system according to any one of claims 5 to 7, wherein the exhaust gas purifying catalyst has an SOx coating based on a predetermined parameter indicating an operating state of the gas fuel engine. The desorption control unit further includes a determination unit that determines whether or not the operation state does not cause poisoning, and the desorption control unit controls the heating unit when the operation state does not cause the SOx poisoning to control the heating unit from the adsorption unit. A gas fuel engine system characterized by desorbing an odorant.

  In the eighth aspect of the present invention, the determining means determines whether or not the exhaust gas purifying catalyst is in an operating state in which SOx poisoning (sulfur poisoning) does not occur, based on a predetermined parameter indicating the operating state of the gas fuel engine. The desorption control unit controls the heating unit to desorb the odorant from the adsorption unit when the operation state is such that SOx poisoning does not occur. Therefore, in the eighth aspect of the present invention, the adsorption means can be regenerated without causing SOx poisoning of the exhaust gas purification catalyst.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, embodiment shown below and its deformation | transformation are only an illustration to the last, and this invention is not necessarily limited by these.

  FIG. 1 is an overall schematic diagram showing a schematic configuration of a gas fuel engine system 1 according to a first embodiment of the present invention. The CNG engine 10 according to the present embodiment is an in-cylinder direct injection internal combustion engine that injects CNG fuel into a combustion chamber 10a by an injector 17, and is mounted on a vehicle.

  The combustion chamber 10a includes a cylinder bore, a cylinder head (not shown), and a piston that is reciprocally disposed in the cylinder bore. A concave cavity is formed in the intake side portion of the upper surface of the piston in order to establish so-called stratified combustion. A spark plug is disposed substantially at the center of the combustion chamber 10a. An intake valve (not shown) facing the combustion chamber 10a is provided with an intake valve, and an exhaust valve is provided with the exhaust port. The injector 17 is disposed in the combustion chamber 10a so that it can be directly injected.

  The CNG engine 10 basically has the same configuration as that of a normal in-cylinder direct injection gasoline engine. However, in order to be able to supply CNG fuel, the configuration of the fuel supply system is a gasoline engine. Is different.

  The CNG fuel tank 12 is a cylinder for storing CNG fuel in a pressurized state at a high pressure (for example, about 20 MPa at the maximum). The delivery pipe 13 is for distributing the CNG fuel supplied via the high pressure regulator 15 to the injectors 17.

  The CNG fuel tank 12 and the delivery pipe 13 are connected by a fuel supply pipe 14. The high pressure regulator 15 provided in the middle of the fuel supply pipe 14 reduces the pressure of the CNG fuel to a predetermined regulator pressure Pa (for example, about 0.5 MPa).

An odor sensor 16 which is a sulfur component detection means in the present invention is provided in the middle of the fuel supply pipe 14 and downstream of the high pressure regulator 15. Various conventionally known odor sensors 16 can be used. For example, an oxide semiconductor layer such as SnO ₂ (tin oxide) is formed on an Al ₂ O ₃ (alumina) substrate, and an electric heater for heating is provided. A semiconductor odor sensor can be used. In this type of semiconductor odor sensor, the odor intensity can be detected by an increase in electric resistance when oxygen adsorbed on the oxide semiconductor layer is combined with molecules of the odor substance. In this embodiment, by using the odor sensor 16 as the sulfur component detection means, even a very small amount of odorant can be detected with high sensitivity.

  A three-way catalyst 26 and a NOx storage reduction catalyst (hereinafter referred to as NSR catalyst) 27 are connected to the exhaust side of the combustion chamber 10 a via an exhaust manifold 25. The downstream side of the NSR catalyst 27 is open to the atmosphere via a silencer (not shown). The three-way catalyst 26 and the NSR catalyst 27 are catalyst powders supported on a carrier made of ceramic formed in a honeycomb shape. Examples of the catalyst supported on the three-way catalyst 26 include a Pt / Pd / Rh catalyst, a Pt / Pd catalyst, a Pt / Rh catalyst, a Pd / Rh catalyst, and the like. Examples of the catalyst supported on the NSR catalyst 27 include a Li / Pt catalyst.

  The electronic control unit (ECU) 30 is configured as a well-known one-chip microprocessor including a CPU, a RAM, a ROM, a backup RAM, and an input / output interface that are coupled to each other by a bidirectional bus. On the input side of the ECU 30, in addition to the odor sensor 16 described above, a water temperature sensor 31 provided in the cooling water path of the CNG engine 10, a crank angle sensor 32 provided near the crankshaft of the CNG engine 10, and the CNG engine 10 Various sensors such as an air flow meter 33 for detecting the intake air amount provided upstream of the intake passage, an intake air temperature sensor 34 for detecting the intake air temperature, and a throttle sensor 35 for detecting the opening of a throttle valve (not shown) are connected. Has been. Various actuators such as an injector 17 and a high-pressure regulator 15 are connected to the output side of the ECU 30. The ECU 30 inputs signals from various sensors in accordance with programs stored in the ROM and various maps and reference values, executes arithmetic processing based on the input signals, and controls signals for various actuators based on the calculation results. In addition to the accumulation amount estimation / poisoning recovery process described below, the fuel injection control, the ignition timing control, and the like performed separately from the present invention are executed.

  Deposition amount estimation / poisoning recovery processing in the first embodiment configured as described above will be described below. The accumulation amount estimation / poisoning recovery process shown in FIG. 2 is repeatedly executed at predetermined timings Δt according to the crank angle during operation of the CNG engine 10.

  First, the ECU 30 reads the detection values of the various sensors described above (S10). Next, the ECU 30 calculates the sulfur supply amount to the NSR catalyst 27 (S20). This sulfur supply amount indicates the amount by which the sulfur component contained in the odorant in the gas fuel is supplied to the NSR catalyst 27. The sulfur supply amount is calculated based on the sulfur concentration calculated by referring to a predetermined table based on the output of the odor sensor 16, the fuel injection amount calculated by separate processing, and the engine calculated based on the output of the crank angle sensor 32. It is calculated by multiplying the number of rotations and multiplying this by a predetermined coefficient. The fuel injection amount is determined based on the intake air amount obtained from the output of the air flow meter 33, the engine speed obtained from the output of the crank angle sensor 32, the intake air temperature obtained from the output of the intake air temperature sensor 34, and the output of the throttle sensor 35. It is calculated based on the obtained throttle opening and the engine coolant temperature obtained from the output of the water temperature sensor 31.

  Next, the amount of sulfur discharged from the NSR catalyst 27 is calculated (S30). This sulfur discharge amount indicates the amount of the sulfur component discharged from the NSR catalyst 27 according to the operating conditions of the CNG engine 10, and includes the amount due to poisoning recovery control described later. The sulfur discharge amount is calculated based on the engine water temperature detected by the water temperature sensor 31, the engine speed NE detected by the crank angle sensor 32, and the engine speed NE and the intake air amount Q from the air flow meter 33. Is estimated (calculated) using a predetermined map based on the engine load (Q / NE).

  Next, the value of the sulfur accumulation amount A in the NSR catalyst 27 is updated by adding the sulfur supply amount calculated in step S20 and subtracting the sulfur discharge amount calculated in step S30 (S40). The value of the sulfur accumulation amount A is recorded in a predetermined storage area in the backup RAM of the ECU 30, and in the subsequent processing cycle, the sulfur supply amount (S20) is added to the stored value or the sulfur emission amount. By the subtraction of (S30), it is updated sequentially.

  Next, it is determined whether the updated value of the current sulfur accumulation amount A is equal to or greater than the recovery control start threshold value At1 (S50). This recovery control start threshold value At1 is experimentally determined in advance to such a value that, when the amount of sulfur deposition in the NSR catalyst 27 is less than this, the influence on the catalyst performance by sulfur poisoning can be practically ignored.

  If the determination in step S50 is affirmative, that is, if the current value of the sulfur accumulation amount A is equal to or greater than the recovery control start threshold value At1, poisoning recovery control is executed (S60). The poisoning recovery control includes enrichment of the air-fuel ratio due to a temporary increase in the fuel injection amount. The temporary increase of the fuel injection amount is performed by adding a predetermined addition value to the target fuel injection amount or multiplying a predetermined increase coefficient in the fuel injection control performed separately.

  If the determination in step S50 is negative, that is, if the current value of the sulfur accumulation amount A is less than the recovery control start threshold value At1, it is next determined whether the sulfur accumulation amount A is equal to or less than a predetermined recovery control end threshold value At2. (S70). This recovery control end threshold value At2 is experimentally determined in advance to a value sufficiently smaller than the recovery control start threshold value At1 in order to avoid a situation in which the sulfur accumulation amount A continues to rise and fall in the vicinity of the above-described recovery control start threshold value At1. Shall.

  As a result of the above processing, the poisoning recovery control in step S60 is repeatedly executed from when the sulfur accumulation amount A exceeds the recovery control start threshold value At1 to below the recovery control end threshold value At2 (S60), and NSR. The sulfur component deposited in the catalyst 27 is removed by poisoning recovery control. Further, when the sulfur accumulation amount A falls below the recovery control end threshold value At2, poisoning recovery control is not performed until the sulfur accumulation amount A becomes equal to or higher than the recovery control start threshold value At1 thereafter.

  Here, in this embodiment, since the odor sensor 16 which is a sulfur component detection means is provided in the fuel supply path to the CNG engine 10, the measurement is not affected by the exhaust heat, and therefore the NSR catalyst 27 which is a catalyst device. The amount of sulfur component supplied to can be estimated more accurately.

  In this embodiment, since the odor sensor 16 having higher sensitivity than the SOx sensor is used as the sulfur component detection means, the measurement can be performed with particularly high accuracy.

  In this embodiment, the poisoning recovery control is performed on the condition that the sulfur accumulation amount A exceeds the recovery control start threshold value At1, but the temperature of the NSR catalyst 27 exceeds the predetermined threshold value. May be an additional condition for starting poisoning recovery control. Further, when a heating means such as an electric heater is added to the NSR catalyst 27 and the temperature of the NSR catalyst 27 is lower than a predetermined value, the NSR catalyst 27 is heated by the heater and the temperature of the NSR catalyst 27 is set to a predetermined value. The poisoning recovery control may be started on the condition that the value is reached.

  Next, a second embodiment will be described. The gas fuel engine system 101 according to the second embodiment shown in FIG. 3 is provided in the fuel supply pipe 14 that is a fuel supply path and upstream of the odor sensor 16 that is a sulfur component detection means. A sulfur compound adsorbing cartridge (hereinafter referred to as an adsorbing cartridge) 50 is provided, which adsorbs an odorant from gas fuel and determines and outputs a deterioration state of the adsorbing cartridge 50 based on a detection value of the odor sensor 16.

  The adsorption cartridge 50 is formed by connecting gas pipes to both ends of a container filled with a deodorant of an appropriate shape such as a powdery body, a spherical body, a honeycomb shape, etc. In the case where there is a possibility of diffusing as the gas passes, it is preferable to prevent diffusion by providing filters on both sides of the gas. For example, if a deodorizer obtained by superposing a honeycomb structure Mn—Fe catalyst and an Au—Fe catalyst is used, the gas fuel passes through the deodorizer, so that the odor of S (sulfur) in the gas fuel is reduced. Deodorized by the Mn-Fe catalyst, and the odor of N (amine) is deodorized by the Au-Fe catalyst. In addition, what was made porous as a deodorizing agent is especially effective.

  The ECU 130 in the second embodiment is configured to execute a predetermined warning output, for example, a warning signal output to the display computer 132 that displays a character message on the display device 131 in the driver's seat. Since the remaining mechanical configuration of the second embodiment is the same as that of the first embodiment, the same reference numerals are given and detailed description thereof is omitted.

  Processing in the second embodiment will be described. In FIG. 4, first, the detection value of the odor sensor 16 is read (S110). Next, the detected value of the read odor sensor 16 is compared with a predetermined threshold value in the ECU 130 (S120). This threshold value is a detection value that is considered to be output by the odor sensor 16 when the adsorption amount of the adsorption cartridge 50 is saturated, and in a region smaller than that value (close to 0), the influence of the sulfur poisoning on the catalyst performance. Such a threshold value can be determined by experiment. If the detection value of the odor sensor 16 is equal to or smaller than the threshold value in step S120, the process returns as a result of affirmative determination.

And when the detection value of the odor sensor 16 exceeds the threshold value in step S120,
Accumulation amount estimation / poisoning recovery processing is executed (S130). This accumulation amount estimation / poisoning recovery process is the same as the series of processes shown in the flow chart of FIG. 2 in the first embodiment described above, and the sulfur supply amount and sulfur discharge amount in the NSR catalyst 27 are taken into consideration. The calculation of the present sulfur deposition amount and the poisoning recovery control according to the calculated sulfur deposition amount are included. Note that the value of the sulfur accumulation amount A is recorded in a predetermined storage area in the backup RAM of the ECU 130, and when the accumulation amount estimation / poisoning recovery process is executed next, addition to the stored value or It is updated sequentially by subtraction.

  Next, a warning is output by the ECU 130 (S140). This warning output is performed by outputting a warning signal to the display computer 132 described above. In response to the output of the warning signal, the display computer 132 controls the display device 131 in the passenger compartment, and displays a text message for the driver, particularly a message indicating deterioration of the suction cartridge 50 or an abnormality of the odor sensor 16. .

  As described above, in the second embodiment, the adsorption cartridge 50 (adsorption means) provided in the fuel supply pipe 14 that is the fuel supply path can adsorb and remove the odorant from the gas fuel, and the adsorption cartridge 50 Since it is provided upstream of the odor sensor 16 (sulfur component detection means), the deterioration state of the adsorption cartridge 50 can also be detected using the detection value of the odor sensor 16. Further, since the information indicating the deterioration state of the suction cartridge 50 is output by the processing of the ECU 130, the user can know the deterioration state of the suction cartridge 50 by this output.

  In the second embodiment, the fact that the suction cartridge 50 has deteriorated is output by displaying a character message on the display device 131. However, the deterioration state is output not only by displaying a character message but also by playing a voice message, warning light It may be performed by other output means such as turning on or appending to an abnormality log file that can be read out by a maintenance operator's diagnosis operation.

  Next, a third embodiment will be described. The gas fuel engine system 201 according to the third embodiment shown in FIG. 5 is provided with a plurality of adsorption cartridges 50 similar to those of the second embodiment in the fuel supply pipe 14 and further upstream of each adsorption cartridge 50. An upstream valve 51 is provided, and a check valve 52 is provided on the downstream side. The upstream valve 51 is a motor-driven on-off valve. The ECU 230 in the third embodiment is configured to be able to individually open and close each upstream valve 51 in addition to the various controls in the second embodiment. The remaining configuration in the third embodiment is the same as that in the second embodiment, and a detailed description thereof will be omitted.

  Processing in the third embodiment will be described. In FIG. 6, first, the detection value of the odor sensor 16 is read (S210). Next, the detected value of the read odor sensor 16 is compared with a predetermined threshold value in the ECU 230 (S220). As this threshold value, a detection value (used in step S120 of the second embodiment) that is considered to be output by the odor sensor 16 when the adsorption amount of the adsorption cartridge 50 is saturated is used. If the detection value of the odor sensor 16 is equal to or smaller than the threshold value in step S220, the process returns as a result of affirmative determination.

  If the detected value of the odor sensor 16 exceeds the threshold value in step S220, the sulfur content leaked from the adsorption cartridge 50 can affect the NSR catalyst 27. Is executed (S230). This accumulation amount estimation / poisoning recovery process is the same as the series of processes shown in the flowchart of FIG. 2 in the first embodiment described above. It should be noted that the value of the sulfur accumulation amount after the processing of step S230 is recorded in a predetermined storage area in the backup RAM of the ECU 230, and this storage is performed when the accumulation amount estimation / poisoning recovery process is executed next. It is sequentially updated by addition or subtraction to the value obtained.

  Next, it is determined whether all the suction cartridges 50 have been used (S240). Here, only the first suction cartridge 50 has been used, and the other suction cartridges 50 are unused, so a negative determination is made. Next, the upstream valve 51 corresponding to the next adsorption cartridge 50 is opened (S250), and the upstream valve 51 corresponding to the adsorption cartridge 50 in use is closed (S260). By the processing in steps S250 and S260, the supply destination of the gas fuel to the adsorption cartridge 50 as the adsorption means is switched from the adsorption cartridge 50 in use to the adsorption cartridge 50 of the next order.

  The processes in steps S210 to S260 are repeated until all the suction cartridges 50 are used up. When all the suction cartridges 50 have been used (degraded state), a negative determination is made in step S240, and a warning output is performed (S270). This warning output is performed by outputting a warning signal to the display computer 132. In response to the output of the warning signal, the display device 132 controls the display device 131 in the passenger compartment and displays a text message for the driver.

  As described above, in the third embodiment, gas fuel can be selectively supplied to each of a plurality of adsorption cartridges 50 provided in parallel by the upstream valve 51 as switching means provided in the fuel supply path. By sequentially switching the adsorption cartridge 50 to an unused adsorption cartridge 50, the sulfur component in the gas fuel can be continuously removed.

  Although the four suction cartridges 50 are used in the third embodiment, the number of suction cartridges (suction means) connected in parallel can be arbitrarily set. In the third embodiment, the warning output is made when all the prepared number of suction cartridges 50 have been used, but the warning output timing is, for example, one unused suction cartridge. Arbitrary timings can be selected, such as the point in time.

  Next, a fourth embodiment will be described. The gas fuel engine system 301 according to the fourth embodiment shown in FIG. 7 is an electric heating system that further heats the adsorption cartridge 50 in a system in which the adsorption cartridge 50 similar to that of the second embodiment is provided in the fuel supply pipe 14. A heater (heating means) 55 and a heater power supply circuit 56 for supplying electric power to the electric heater 55 are provided.

As the electric heater 55, for example, a PTC thermistor (Positive Temperature Coefficient Thermistor) made of a semiconductor ceramic mainly composed of barium titanate (BaTiO ₃ ) is preferably used. The electric heater 55 is connected to a heater power supply circuit 56 for supplying electric power thereto. The heater power supply circuit 56 boosts a DC voltage from a battery (DC power supply) (not shown) and supplies power to the electric heater 55 at an arbitrary voltage value and timing, and includes a DC / DC converter and the like. Yes.

  The ECU 330 in the fourth embodiment is configured to control the electric heater 55 in order to desorb the odorant from the adsorption cartridge 50 in addition to the various controls in the second embodiment. The remaining configuration in the fourth embodiment is the same as that in the second embodiment, and a detailed description thereof will be omitted.

  Processing in the fourth embodiment will be described. In FIG. 8, first, the detection value of the odor sensor 16 is read (S310). Next, the read detection value of the odor sensor 16 is compared with a predetermined threshold value in the ECU 230 (S320). As this threshold value, a detection value (used in step S120 of the second embodiment) that is considered to be output by the odor sensor 16 when the adsorption amount of the adsorption cartridge 50 is saturated is used. If the detected value of the odor sensor 16 is equal to or smaller than the threshold value in step S320, the process returns as a result of affirmative determination.

  If the detection value of the odor sensor 16 exceeds the threshold value in step S320, the suction cartridge 50 is in a deteriorated state (a state in which the suction amount is saturated), and thus the control proceeds to step S330 and subsequent steps. First, it is determined whether the below-described heating by the electric heater 55 has been continuously performed a predetermined number of times or more (S330). When an affirmative determination is made here, leakage of sulfur components from the adsorption cartridge 50 is detected despite continuous heating for a predetermined number of times, that is, the adsorption cartridge 50 is deteriorated or the odor sensor 16 is detected. Is in a state of failure, warning output is performed (S380). This warning output is performed by outputting a warning signal to the display computer 132, and a character message is displayed on the display device 131 in accordance with the output of the warning signal.

  Next, accumulation amount estimation / poisoning recovery processing is executed (S340). This accumulation amount estimation / poisoning recovery process is the same as the series of processes shown in the flowchart of FIG. 2 in the first embodiment described above.

  Next, the electric heater 55 is turned on (S350). The energization of the electric heater 55 here is continuously performed until a predetermined time elapses (S360), and the electric heater 55 is turned off on the condition (S370).

  As a result of the above processing, when the occlusion amount of the adsorption cartridge 50 approaches the upper limit value, the adsorption cartridge 50 is heated by the electric heater 55, and the sulfur component occluded in the adsorption cartridge 50 is desorbed.

  As described above, in the fourth embodiment, the ECU 330 controls the electric heater 55 (heating means) that heats the adsorption cartridge 50 (adsorption means) to desorb the odorant from the adsorption cartridge 50. The period of use can be extended by regenerating.

  In addition, as a heating means for heating the adsorption cartridge 50, other types of electric heaters such as those using Ni—Cr wire may be used as long as the sulfur component can be desorbed from the adsorption cartridge 50. In addition, a heater using exhaust heat of the engine such as cooling water or exhaust can be arbitrarily used.

  Next, a fifth embodiment will be described. The gas fuel engine system 401 according to the fifth embodiment shown in FIG. 9 uses an exhaust heat utilization heater 155 as a heating means for heating the adsorption cartridge 50 in a system provided with the adsorption cartridge 50. .

  The exhaust heat utilization heater 155 is a substantially double cylindrical hollow body surrounding the adsorption cartridge 50, and an exhaust introduction passage 156 branched from the downstream side of the NSR catalyst 27 in the exhaust pipe is connected to a part of the heater 155. A discharge pipe 158 is connected to a part of this. An exhaust introduction control valve 157 is provided in the vicinity of the exhaust heat utilization heater 155 in the exhaust introduction passage 156, and a relief valve 159 is provided in the exhaust pipe 158. The exhaust introduction control valve 157 is a motor-driven on-off valve. The ECU 430 in the fifth embodiment is configured to be able to control the opening / closing of the exhaust introduction control valve 157 in addition to the various controls in the second embodiment. The remaining configuration in the fifth embodiment is the same as that in the second embodiment, and a detailed description thereof will be omitted.

  Processing in the fifth embodiment will be described. In FIG. 10, the processes of steps S410, S420, S440, and S480 are the same as the processes of steps S310, S320, S340, and S380 in the fourth embodiment.

  In step S430, it is determined whether the after-mentioned heating by the exhaust heat utilization heater 155 has been continuously performed a predetermined number of times or more. When an affirmative determination is made here, leakage of sulfur components from the adsorption cartridge 50 is detected despite continuous heating for a predetermined number of times, that is, the adsorption cartridge 50 is deteriorated or the odor sensor 16 is detected. Is in a state of failure, warning output is performed (S480).

  When the accumulation amount estimation / poisoning recovery process is executed in step S440, the exhaust introduction control valve 157 is then opened (S450). Here, the exhaust introduction control valve 157 is continuously opened until a predetermined time elapses (S460), and the exhaust introduction control valve 157 is closed on the condition (S470).

  As a result of the above processing, when the occlusion amount of the adsorption cartridge 50 approaches the upper limit value, exhaust gas is introduced into the exhaust heat utilization heater 155 via the exhaust introduction passage 156 by the opening operation of the exhaust introduction control valve 157, and the adsorption cartridge 50 is heated. By this heating, the sulfur component stored in the adsorption cartridge 50 is desorbed. The exhaust gas in the exhaust heat utilization heater 155 is discharged to the outside from the discharge pipe 158 via the relief valve 159. However, since this exhaust gas passes through the NSR catalyst 27, the influence on the environment is insignificant. .

  Next, a sixth embodiment will be described. In general, SOx poisoning (sulfur poisoning) due to components of an odorant in an exhaust gas purifying catalyst is unlikely to occur under conditions where the catalyst is at a high temperature and the air-fuel ratio is on the rich side. Therefore, in the sixth embodiment, in the same mechanical configuration as that of the fourth embodiment (FIG. 7), the NSR catalyst 27 is in the course of operation (that is, without performing poisoning recovery control), so that SOx poisoning does not occur. In the operation state where no SOx poisoning occurs, the electric heater 55 (heating means) is controlled to desorb the odorant from the adsorption cartridge 50.

  In the sixth embodiment, as shown in FIG. 11, a poisoning recovery map 500 in which a poisoning non-occurrence area and a poisoning occurrence area are defined with respect to the engine speed and load is created in advance, and data in a table format is created. Is stored in the ECU. In this poisoning recovery map 500, an area where the rotation speed is large and the load is large is regarded as a poisoning non-occurrence area. The remaining configuration in the sixth embodiment is the same as that in the fourth embodiment, and a detailed description thereof will be omitted.

  Processing in the sixth embodiment will be described. In FIG. 12, the processes of steps S510 to S540 and the processes of S550 to S580 are the same as the processes of steps S310 to S340 and S350 to S380 in the fourth embodiment, respectively.

  When the accumulation amount estimation / poisoning recovery process is executed in step S540, the engine speed and load values, which are parameters indicating the current engine operating state, are read into the ECU, and the values of these values are determined. By referring to the poison recovery map 500, it is determined whether or not the current operation state is within the poisoning non-occurrence region (S545). If the result in step S545 is negative, the processing is returned assuming that SOx poisoning of the NSR catalyst 27 may occur under the current operating conditions.

  If the determination in step S545 is affirmative, that is, if it is determined that the catalyst is in an operating state where no SOx poisoning of the catalyst occurs, the electric heater 55 is turned on (S550), and a predetermined time has passed (S560). ), The electric heater 55 is turned off (S570).

  As a result of the above processing, when the storage amount of the sulfur component in the adsorption cartridge 50 is close to the full amount and the current operation state is within the poisoning-free region, the adsorption cartridge 50 is heated and occluded in the adsorption cartridge 50. The sulfur component is removed.

  As described above, in the sixth embodiment, the odorant is heated by heating the adsorption cartridge 50 when the exhaust gas purification catalyst is in an operation state in which SOx poisoning does not occur based on the predetermined parameter indicating the operation state of the engine. Is removed. Therefore, in this embodiment, the adsorption means can be regenerated without causing SOx poisoning of the exhaust gas purification catalyst.

  In the sixth embodiment, the electric heater 55 is used as a heating means for heating the adsorption cartridge 50. However, instead of the electric heater 55, other heating means such as the exhaust heat utilization heater 155 in the fifth embodiment is used. May be.

  In the sixth embodiment, the engine speed and the load are used as the predetermined parameters indicating the engine operating state. However, the predetermined parameters indicating the engine operating state in the present invention are the occurrence of poisoning of the exhaust gas purification catalyst. Various other parameters that can be affected, such as engine water temperature, air-fuel ratio, or catalyst temperature directly detected by providing a catalyst temperature sensor in or near the NSR catalyst 27, can be arbitrarily employed.

  In the sixth embodiment, when the current occlusion amount of the adsorption cartridge 50 is close to the full amount, the adsorption cartridge 50 is desorbed by heating for a certain time. Depending on the amount of sulfur component stored in the adsorption cartridge 50, the heating execution time may be continuously or discretely changed from zero (no heating is performed at all) to a maximum value. In such a case, a second odor sensor similar to the odor sensor 16 is installed in the fuel supply pipe 14 upstream of the adsorption cartridge 50, and the adsorption cartridge is calculated by integrating the detection values of the second odor sensor. In addition to estimating the current storage amount of the sulfur component at 50, it is assumed that the estimated storage amount exceeds a predetermined threshold, or that heating is performed for a time corresponding to the estimated storage amount. Is preferably performed.

  Next, a seventh embodiment will be described. The seventh embodiment relates to a bi-fuel engine that can supply CNG and gasoline to a common combustion chamber. In recent years, various types of bi-fuel engines capable of supplying gaseous fuel and liquid fuel to a common combustion chamber have been proposed. In such a bi-fuel engine, in general, gaseous fuel is supplied to the engine during normal operation and liquid fuel supply is stopped, and when the residual gaseous fuel amount becomes lower than the lower limit threshold, It is assumed that the liquid fuel is supplied and the gas fuel supply is stopped. However, when considering adding a gasoline supply system component to the mechanical configuration of the first to sixth embodiments, when switching from CNG operation to gasoline operation, the cumulative NSR at that time If the values related to the history such as the sulfur accumulation amount A in the catalyst 27 and the past execution timing, time, and number of times of the poisoning recovery control are cleared, there is a possibility that the subsequent poisoning recovery control may not be appropriately performed. is there. Therefore, in the seventh embodiment, even when switching between operation with gaseous fuel and operation with liquid fuel is performed in a bi-fuel engine, the numerical values related to the history as described above are maintained. is there.

  The bi-fuel engine system according to the seventh embodiment has a mechanical configuration similar to that of the first to sixth embodiments, further includes a gasoline injection valve that can be injected into an intake passage in the intake manifold. A fuel pump for pressurizing gasoline is provided between the valve and a gasoline tank as a liquid fuel container. These gasoline injection valve and fuel pump are controlled based on output signals from the ECU.

  Processing in the seventh embodiment will be described. In FIG. 13, first, the detection values of various sensors are read in the ECU (S610). Next, the ECU determines whether a predetermined gasoline selection condition is satisfied (S611). The gasoline selection condition here is, for example, that the residual gaseous fuel amount is less than the lower limit threshold. When the condition is not satisfied, CNG operation control is performed (S612), and when the condition is satisfied, gasoline operation control is performed (S614). These CNG operation control and gasoline operation control are normal travel control such as control of fuel injection amount based on engine speed, load, accelerator pedal operation amount, and the like.

  Next, when CNG operation control is performed, the sulfur concentration in the CNG fuel is calculated from the detection value of the odor sensor 16 (S613). When gasoline operation control is performed, a gasoline default value is adopted as the sulfur concentration (S615). Then, the sulfur supply amount to the NSR catalyst 27 is calculated using the value of the sulfur concentration thus determined (S620). The processing after step S630 is the same as the processing after step S30 in the first embodiment (FIG. 2).

  As described above, in the present embodiment, a common sulfur accumulation value is used when CNG fuel is selected and when gasoline is selected, and this sulfur accumulation value is the sulfur concentration of each fuel. Will be updated sequentially based on. Therefore, in this embodiment, even when switching between operation with gaseous fuel and operation with liquid fuel is performed in the bi-fuel engine, as a result of maintaining the numerical value related to the operation history, the subsequent poisoning recovery control is performed. Can continue properly.

  In the seventh embodiment, a fixed value is used as the sulfur concentration of gasoline fuel. However, the sulfur concentration of gasoline fuel may be estimated by some means, and the sulfur accumulation amount may be calculated according to this estimation.

  In each of the above-described embodiments, an example in which the present invention is applied to an engine that realizes so-called stratified combustion has been described. However, sulfur poisoning caused by components such as sulfur contained in the odorant is a so-called stoichiometry at an ideal air-fuel ratio. This may occur even in an engine that establishes combustion, and the present invention can be applied to such a stoichiometric combustion engine (for example, one that uses a three-way catalyst). Moreover, although the said embodiment demonstrated the example which applied this invention about the in-cylinder direct injection type engine, this invention is applicable not only to an in-cylinder direct injection type engine but a port injection type or a mixer type engine. .

1 is an overall schematic diagram of a gas fuel engine system according to a first embodiment of the present invention. It is a flowchart which shows the accumulation amount estimation and poisoning recovery process in 1st Embodiment. It is a whole schematic diagram of the gas fuel engine system concerning a 2nd embodiment. It is a flowchart which shows the degradation state detection process in 2nd Embodiment. It is a whole schematic diagram of the gas fuel engine system concerning a 3rd embodiment. It is a flowchart which shows the adsorption cartridge switching process in 3rd Embodiment. It is a whole schematic diagram of the gas fuel engine system concerning a 4th embodiment. It is a flowchart which shows the odorant removal | desorption process in 4th Embodiment. It is a whole schematic diagram of the gas fuel engine system concerning a 5th embodiment. It is a flowchart which shows the odorant removal | desorption process in 5th Embodiment. It is a graph which shows the example of a setting of the poisoning recovery map in 6th Embodiment. It is a flowchart which shows the odorant removal | desorption process in 6th Embodiment. It is a flowchart which shows the accumulation amount estimation and poisoning recovery process in 7th Embodiment.

Explanation of symbols

10 CNG Engine 12 CNG Fuel Tank 13 Delivery Pipe 16 Odor Sensor (Sulfur Component Detection Means)
17 Injector 27 NSR catalyst (exhaust gas purification catalyst)
30, 130, 230, 330, 430 Electronic control unit (ECU)
50 Adsorption cartridge (adsorption means)
51 Upstream valve 55 Electric heater (heating means)
155 Exhaust heat utilization heater (heating means)

Claims (8)

A sulfur component detection means provided in a fuel supply path to a gas fuel engine having an exhaust gas purification catalyst on the exhaust side;
A deposit amount estimating means for estimating an SOx deposit amount in the exhaust gas purifying catalyst based on a detection value of the sulfur component detecting means;
Poisoning recovery control means for performing SOx poisoning recovery control on the exhaust gas purifying catalyst when the estimated SOx accumulation amount exceeds a predetermined threshold;
A gas fuel engine system comprising: A gas fuel engine system according to claim 1,
The gas fuel engine system, wherein the sulfur component detection means is an odor sensor. A gas fuel engine system according to claim 1 or 2,
An adsorbing means for adsorbing an odorant from gas fuel provided in the fuel supply path and upstream of the sulfur component detecting means;
A deterioration state output means for outputting a deterioration state of the adsorption means based on a detection value of the sulfur component detection means;
A gas fuel engine system further comprising: A gas fuel engine system according to claim 3,
A gas fuel engine system, wherein a plurality of the adsorbing means are provided in parallel, and a switching means for selectively supplying gas fuel to each of the adsorbing means is provided in the fuel supply path. . A gas fuel engine system according to claim 1 or 2,
An adsorbing means for adsorbing an odorant from gas fuel provided in the fuel supply path and upstream of the sulfur component detecting means;
Heating means for heating the adsorption means;
Desorption control means for controlling the heating means to desorb the odorant from the adsorption means;
A gas fuel engine system comprising: A gas fuel engine system according to claim 5,
The gas fuel engine system, wherein the heating means is an electric heater. A gas fuel engine system according to claim 5,
The gas fuel engine system, wherein the heating means is an exhaust heat utilization heater. A gas fuel engine system according to any one of claims 5 to 7,
A determination unit for determining whether or not the exhaust gas purification catalyst is in an operation state in which SOx poisoning does not occur based on a predetermined parameter indicating an operation state of the gas fuel engine;
The gas fuel engine system, wherein the desorption control unit controls the heating unit to desorb the odorant from the adsorption unit in an operation state in which the SOx poisoning does not occur.

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