JP2005155444A - Exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device capable of improving fuel economy by improving the regenerative efficiency of a particulate filter since a driver can determine the operating state of a vehicle at that time and forcibly regenerate the particulate filter arbitrarily by transmitting a timing suitable for the regeneration of the particulate filter to the driver. <P>SOLUTION: When the deposited amount of particulate on the particulate filter 11 is equal to or more than a threshold requiring regeneration and the temperature of the particulate filter 11 is equal to or more than a regenerative start matching time or higher, an indication lamp 19 is made flash to promote the driver to regenerate the particulate filter 11 so that the driver operates a regenerative switch 20 to forcibly burn and remove the particulates collected by the particulate filter 11 so as to regenerative the particulate filter 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust emission control device.

  Particulate matter (particulate matter) discharged from a diesel engine as an internal combustion engine is mainly composed of carbonaceous soot and SOF (Soluble Organic Fraction) composed of high-boiling hydrocarbon components. As a component, the composition further contains a trace amount of sulfate (mist-like sulfuric acid component). As a measure for reducing this type of particulates, a particulate filter is placed in the middle of the exhaust pipe through which the exhaust gas flows. It has been traditionally equipped.

  This type of particulate filter has a porous honeycomb structure made of a ceramic such as cordierite, and the inlets of the flow paths partitioned in a lattice pattern are alternately sealed, and the inlets are not sealed. About the flow path, the exit is sealed, and only the exhaust gas which permeate | transmitted the porous thin wall which divides each flow path is discharged | emitted downstream.

  Then, the particulates in the exhaust gas are collected and deposited on the inner surface of the porous thin wall, so that the particulates are appropriately burned and removed before the exhaust resistance increases due to clogging. It is necessary to regenerate, but in normal diesel engine operating conditions, there are few opportunities to obtain exhaust temperatures that are high enough for the particulates to self-combust. For example, an appropriate amount for alumina loaded with platinum A catalyst regeneration type particulate filter in which an oxidation catalyst formed by adding a rare earth element such as cerium is integrally supported is being put to practical use.

  That is, if such a catalyst regeneration type particulate filter is employed, the oxidation reaction of the collected particulates is promoted to lower the ignition temperature, and the particulates can be burned and removed even at an exhaust temperature lower than the conventional one. It becomes possible.

  However, even when such a catalyst regeneration type particulate filter is employed, the oxidation catalyst supported by the particulate filter has an active temperature region, and the exhaust temperature is below the lower limit of activation temperature. In the low operating range, the particulates are not burned and removed well, and the trapped amount exceeds the processing amount of the particulates, so if the operating state at such a low exhaust temperature continues, the oxidation catalyst becomes active. Since the particulate filter may not be regenerated well and the particulate filter may fall into an over-collected state because the particulate filter is not collected. It is considered that the particulate filter is forcibly regenerated by adding fuel to the exhaust gas.

  In other words, if fuel is added upstream from the particulate filter, the added fuel undergoes an oxidation reaction on the oxidation catalyst of the particulate filter, and the heat of reaction raises the filter bed temperature and burns up the particulate. Thus, regeneration of the particulate filter is achieved.

As an example of an exhaust emission control device provided with the particulate filter as described above, there is Patent Document 1, for example.
JP 2003-155916 A

  By the way, in the prior art, for example, a pressure sensor is arranged before and after sandwiching the particulate filter and the differential pressure between the inlet side and the outlet side is obtained to determine the over-collection state, or the engine speed and load are determined. Based on the particulate generation map, the particulate discharge amount at that time is calculated, and the particulate discharge amount is integrated to estimate the particulate accumulation amount in the particulate filter and judge the over-collection state. Thus, the design concept of performing forced regeneration of the particulate filter automatically during traveling has become mainstream.

  However, the load fluctuates greatly while driving, and there are many unstable factors in executing forced regeneration of the particulate filter, especially in buses that operate in congested routes in central Tokyo and areas where delivery destinations are dense. In vehicles such as trucks that perform home delivery services, even if forced regeneration of the particulate filter is automatically applied during traveling, regeneration may not always be completed, so traveling conditions for performing such forced regeneration are easy. For vehicles that do not operate properly, it takes time to complete regeneration of the particulate filter, and the amount of fuel added upstream from the particulate filter increases accordingly, resulting in poor fuel consumption. There was concern.

  In view of such circumstances, the present invention conveys to the driver a time suitable for regeneration of the particulate filter, so that the driver can arbitrarily force the particulate filter after judging the driving situation of the vehicle at that time. It is an object of the present invention to provide an exhaust emission control device that can be regenerated, can improve the regeneration efficiency of the particulate filter, and leads to improved fuel efficiency.

The present invention relates to an exhaust purification apparatus equipped with a particulate filter in the middle of an exhaust pipe through which exhaust gas from an engine flows.
Estimating the amount of particulates accumulated in the particulate filter by calculating the particulate emissions at that time from the particulate matter generation map based on the engine speed and load, and integrating the particulate emissions. Means,
Temperature detecting means for detecting the temperature of the particulate filter;
When the particulate accumulation amount in the particulate filter estimated by the accumulation amount estimation means is equal to or higher than a threshold value that requires regeneration, and the temperature of the particulate filter detected by the temperature detection means is equal to or higher than the regeneration start adapted temperature. And an arrival transmission means for prompting the driver to regenerate the particulate filter,
Forced regeneration means for forcibly burning and removing the particulates collected by the particulate filter to regenerate the particulate filter;
Exhaust gas purification comprising: operating means provided in a driver's seat so that the driver can operate the forced regeneration means when regeneration of the particulate filter is urged by the arrival transmission means of the regeneration time It depends on the device.

  According to the above means, the following operation can be obtained.

  During the operation of the vehicle, the accumulation amount of the particulate filter in the particulate filter is estimated by the accumulation amount estimation means, the temperature of the particulate filter is detected by the temperature detection means, and the particulate filter estimated by the accumulation amount estimation means When the particulate accumulation amount at or above is equal to or higher than a threshold that requires regeneration and the temperature of the particulate filter detected by the temperature detection means is equal to or higher than the regeneration start adaptable temperature, the driver is notified by the regeneration time arrival transmission means. The particulate filter is urged to regenerate, and when the driver operates the operating means, the forced regeneration means is activated, and the particulates collected by the particulate filter are forcibly burned and removed. The curate filter is regenerated.

  As a result, even for vehicles with a driving mode in which the driving conditions for executing forced regeneration are not easily established, the driver is informed of the driving conditions of the vehicle at that time by informing the driver of the appropriate time for regeneration of the particulate filter. This makes it possible to reliably and efficiently regenerate the particulate filter, so that less fuel is added on the upstream side of the particulate filter and fuel efficiency is improved. In addition, when the driver is prompted to regenerate the particulate filter by the means for transmitting the arrival of the regeneration time, the driver can intentionally postpone the regeneration start without operating the operation means immediately, so that the regeneration is completed. It is also possible to lengthen the interval and further improve fuel efficiency.

  In the exhaust emission control device, the regeneration time arrival transmission means may be a display lamp that flashes in response to the regeneration time arrival signal from the control device when prompting the driver to regenerate the particulate filter.

  According to the exhaust gas purification apparatus of the present invention, the driver is forced to force the particulate filter after judging the driving situation of the vehicle at that time by informing the driver of the time suitable for regeneration of the particulate filter. The regeneration efficiency of the particulate filter can be improved, and the excellent effect of improving fuel efficiency can be achieved.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 4 show an embodiment of the present invention. Reference numeral 1 in FIG. 1 denotes a vehicle diesel engine equipped with a turbocharger 2 and equipped with an automatic transmission (not shown). The intake air 4 introduced from the air cleaner 3 is introduced into the compressor 2a of the turbocharger 2 through the intake pipe 5 and pressurized, and the pressurized intake air 4 is distributed to each cylinder of the diesel engine 1 via the intercooler 6. It has been introduced.

  Further, the exhaust gas 8 discharged from each cylinder of the diesel engine 1 through the exhaust manifold 7 is sent to the turbine 2b of the turbocharger 2, and the exhaust gas 8 driving the turbine 2b passes through the exhaust pipe 9 to the outside of the vehicle. To be discharged.

  A filter case 10 is interposed in the middle of the exhaust pipe 9, and a catalyst regeneration type particulate filter 11 that integrally carries an oxidation catalyst is provided in the rear stage in the filter case 10. As shown in an enlarged view in FIG. 2, the particulate filter 11 has a porous honeycomb structure made of ceramic, and the inlets of the respective flow paths 11a partitioned in a lattice pattern are alternately arranged. For the flow path 11a that is sealed and whose inlet is not sealed, its outlet is sealed, and only the exhaust gas 8 that has permeated through the porous thin wall 11b that defines each flow path 11a is downstream. It is designed to be discharged to the side.

  Further, a flow-through type oxidation catalyst 12 having a honeycomb structure as shown in an enlarged view in FIG. 3 is accommodated in a position immediately before the particulate filter 11 in the filter case 10.

  The accelerator of the driver's seat (not shown) is provided with an accelerator sensor 16 (load sensor) that detects the accelerator opening as a load of the diesel engine 1, and at an appropriate position of the diesel engine 1, its rotation. A rotation sensor 17 for detecting the number is provided, and the accelerator opening signal 16a and the rotation speed signal 17a from the accelerator sensor 16 and the rotation sensor 17 are provided in a control device 14 constituting an engine control computer (ECU: Electronic Control Unit). In the control device 14, the particulate generation amount map (based on the engine speed detected by the rotation sensor 17 and the accelerator opening (load) detected by the accelerator sensor 16 ( From the map in the steady state of the engine) The accumulated amount of the particulates is estimated and the accumulated amount of the particulates in the particulate filter 11 is estimated, so that the accumulated amount of the particulates in the particulate filter 11 is estimated. Further, the control device 14 determines whether or not the particulate accumulation amount in the particulate filter 11 is equal to or greater than a threshold value that requires regeneration.

  A temperature sensor 13 is provided between the oxidation catalyst 12 and the particulate filter 11 in the filter case 10 as temperature detecting means for measuring the temperature of the exhaust gas 8 as a substitute value for the filter bed temperature of the particulate filter 11. It is equipped and the detection signal 13a of the temperature sensor 13 is input to the control device 14, while the control device 14 injects fuel into each cylinder of the diesel engine 1. A fuel injection signal 15 a for instructing the fuel injection timing and the injection amount to 15 is output.

  Here, the fuel injection device 15 is constituted by a plurality of injectors (not shown) provided for each cylinder, and the solenoid valve of each injector is controlled to open by the fuel injection signal 15a, and the fuel injection timing. In addition, the injection amount (valve opening time) is appropriately controlled.

  Further, on the instrument panel or the like in the driver's seat, the controller 14 determines that the accumulated amount of the particulates in the particulate filter 11 is equal to or higher than a threshold that requires regeneration, and is detected by the temperature sensor 13. When it is determined that the temperature of the particulate filter 11 is equal to or higher than the regeneration start suitable temperature, the regeneration time arrival signal 19a is received from the control device 14 and blinks to prompt the driver to regenerate the particulate filter 11. A display lamp 19 as an arrival transmission means for the regeneration time and a regeneration switch 20 as an operation means for arbitrarily operating a forced regeneration means described later are provided.

  In the control device 14, the fuel injection signal 15a in the normal mode is determined based on the accelerator opening signal 16a and the rotation speed signal 17a. On the other hand, the regeneration switch 20 is operated by the driver and the regeneration command is issued. When the signal 20a is input, the mode is switched from the normal mode to the forced regeneration mode, and after the main injection of fuel performed near the compression top dead center (crank angle 0 °), the post injection is performed at a timing not ignited later than the compression top dead center. The fuel injection signal 15a for performing the above is determined. When the driver operates the regeneration switch 20 to switch from the normal mode to the forced regeneration mode, the display lamp 19 is switched from the blinking state to the lighting state.

  That is, in the illustrated example, the control device 14 and the fuel injection device 15 constitute the forced regeneration means of the particulate filter 11, and as described above, from the compression top dead center following the main injection. When post-injection is performed at a timing that does not ignite late, unburned fuel (mainly HC: hydrocarbon) is added to the exhaust gas 8 by the post-injection, and this unburned fuel is added to the particulate filter 11. The oxidation reaction is carried out on the surface oxidation catalyst, and the heat of the reaction raises the filter bed temperature, so that the particulates in the particulate filter 11 are burned and removed.

  As for the specific control procedure in the control device 14, as shown in the flowchart of FIG. 4, as a precondition, the regeneration switch 20 is set to permit operation during driving and not to perform forced regeneration automatically. First, it is determined in step S1 whether or not the diesel engine 1 is stopped. If the diesel engine 1 is stopped, the display lamp 19 is held in the off state in step S2, while the diesel engine 1 is stopped. If 1 is not stopped, it is determined in step S3 whether or not the particulate accumulation amount in the particulate filter 11 is equal to or greater than a threshold that requires regeneration.

  If the accumulated amount of the particulates in the particulate filter 11 is not equal to or greater than the threshold value that needs to be regenerated, the display lamp 19 is held off in step S2, while the accumulated amount of the particulates in the particulate filter 11 is the same. If it is equal to or greater than the threshold value that requires regeneration, it is determined in step S4 whether or not regeneration of the particulate filter 11 is prohibited due to a failure of the diesel engine 1.

  If the regeneration of the particulate filter 11 is in a prohibited state, the display lamp 19 is held off in step S2, while if the regeneration of the particulate filter 11 is not in a prohibited state, the regeneration is performed in step S5. It is determined whether or not the switch 20 is ON.

  If the regeneration switch 20 is ON, the display lamp 19 is turned on in step S6. If the regeneration switch 20 is not ON, the temperature of the particulate filter 11 is regenerated in step S7. Judgment is made as to whether or not the temperature is higher than the start compatible temperature.

  If the temperature of the particulate filter 11 is equal to or higher than the regeneration start suitable temperature, the display lamp 19 is blinked in step S8 to prompt the driver to regenerate the particulate filter 11, while the temperature of the particulate filter 11 is increased. If the temperature is not equal to or higher than the regeneration start suitable temperature, the display lamp 19 is held off in step S2.

  Next, the operation of the illustrated example will be described.

  When the vehicle is driven, it is determined that the diesel engine 1 has not stopped in step S1 in FIG. 4 on the assumption that the regeneration switch 20 is permitted to operate during traveling and is not automatically forcedly regenerated. In this case, in the control device 14 as the accumulation amount estimation means, a particulate generation amount map (engine steady state) based on the engine speed detected by the rotation sensor 17 and the accelerator opening (load) detected by the accelerator sensor 16. The particulate discharge amount at that time is calculated from the map in the state), and the particulate discharge amount is integrated to estimate the particulate deposition amount in the particulate filter 11, and the particulate filter 11 in the particulate filter 11. The amount of deposits must be greater than or equal to a threshold that requires regeneration 4 is confirmed in step S3, it is determined in step S4 whether regeneration of the particulate filter 11 is in a prohibited state due to a failure of the diesel engine 1, and regeneration of the particulate filter 11 is not in a prohibited state. In this case, it is determined in step S5 whether or not the regeneration switch 20 is ON.

  Here, if the regeneration switch 20 is ON, the display lamp 19 is turned on in step S6, but if the regeneration switch 20 is not ON, it is detected by the temperature sensor 13 as temperature detecting means. In step S7, it is determined whether or not the temperature of the particulate filter 11 is equal to or higher than the regeneration start adapted temperature. If the temperature of the particulate filter 11 is equal to or higher than the regeneration start adapted temperature, the controller 14 The display lamp 19 as the reproduction time arrival transmission means blinks as shown in step S8 in FIG. 4 by the output reproduction time arrival signal 19a, thereby prompting the driver to regenerate the particulate filter 11.

  Here, when the driver operates the regeneration switch 20 as the operation means, the normal mode is switched to the forced regeneration mode, and compression is performed by the fuel injection signal 15a output from the control device 14 as the forced regeneration means to the fuel injection device 15. Following the main injection of fuel performed near the top dead center (crank angle 0 °), post injection is performed at a timing not ignited later than the compression top dead center, and unburned fuel ( The unburned fuel is oxidized on the oxidation catalyst on the surface of the particulate filter 11, and the heat of the reaction raises the filter bed temperature. The collected particulates are forcibly burned and removed, and the particulate filter 11 is regenerated.

  As a result, even for a vehicle in a driving form in which the driving conditions for executing forced regeneration are not easily established, the driver can drive the vehicle at that time by informing the driver of a time suitable for regeneration of the particulate filter 11. It is possible to reliably and efficiently regenerate the particulate filter 11 after judging the situation, and less fuel is added upstream from the particulate filter 11 and fuel efficiency is improved. Further, when the driver is prompted to regenerate the particulate filter 11 by the blinking of the display lamp 19, the driver deliberately delays the start of regeneration without operating the regeneration switch 20 immediately. It is also possible to lengthen the interval until reproduction and further improve fuel efficiency.

  In this way, by telling the driver a time suitable for regeneration of the particulate filter 11, the driver can arbitrarily regenerate the particulate filter 11 after judging the driving situation of the vehicle at that time. The regeneration efficiency of the filter 11 can be improved, leading to improved fuel efficiency.

  The exhaust emission control device of the present invention is not limited to the illustrated example described above. Instead of using the display lamp 19 as a means for transmitting the arrival of the regeneration time, a multi-information display capable of displaying various information relating to operation in a multiplexed manner Or by using voice guidance to prompt the driver to regenerate the particulate filter 11, and as a forced regeneration means for the particulate filter 11, the fuel injection device 15 injects fuel. Instead of using the means for switching the mode by the control device 14, for example, an injector for fuel addition is separately provided at any location in the middle of the exhaust passage from the exhaust manifold 7 to the exhaust pipe 9. A means of adding fuel into the exhaust gas 8 is adopted, or Such that the heating device such as an electric heater may be adopted a means of supplementary mounted on the particulate filter 11, the other, it is a matter of course that within the scope not departing from the gist of the present invention that various changes and modifications may be made.

It is a schematic structure figure of an example of an embodiment which carries out the present invention. It is sectional drawing which shows the detail of the particulate filter of FIG. It is the perspective view which notched a part which shows the detail of the oxidation catalyst of FIG. It is a flowchart which shows the specific control procedure in an example of embodiment which implements this invention.

Explanation of symbols

1 Diesel engine (engine)
8 Exhaust gas 9 Exhaust pipe 11 Particulate filter 13 Temperature sensor (temperature detection means)
13a Detection signal 14 Control device (deposition amount estimation means, forced regeneration means)
15 Fuel injection device (forced regeneration means)
15a Fuel injection signal 16 Accelerator sensor (deposition amount estimation means)
16a Accelerator opening signal 17 Rotation sensor (deposition amount estimation means)
17a Rotational speed signal 19 Indicating lamp (reproduction time arrival transmission means)
19a Reproduction time arrival signal 20 Reproduction switch (operation means)
20a Regeneration command signal

Claims (2)

In an exhaust purification device equipped with a particulate filter in the middle of an exhaust pipe through which exhaust gas from the engine circulates,
Estimating the amount of particulates accumulated in the particulate filter by calculating the particulate emissions at that time from the particulate matter generation map based on the engine speed and load, and integrating the particulate emissions. Means,
Temperature detecting means for detecting the temperature of the particulate filter;
When the particulate accumulation amount in the particulate filter estimated by the accumulation amount estimation means is equal to or higher than a threshold value that requires regeneration, and the temperature of the particulate filter detected by the temperature detection means is equal to or higher than the regeneration start adapted temperature. And an arrival transmission means for prompting the driver to regenerate the particulate filter,
Forced regeneration means for forcibly burning and removing the particulates collected by the particulate filter to regenerate the particulate filter;
Exhaust gas purification comprising: operating means provided in a driver's seat so that the driver can operate the forced regeneration means when regeneration of the particulate filter is urged by the arrival transmission means of the regeneration time apparatus.   2. The exhaust emission control device according to claim 1, wherein the regeneration time arrival transmission means is a display lamp that flashes in response to a regeneration time arrival signal from the control device when prompting the driver to regenerate the particulate filter.

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