JP2012007571A - Method and system for regenerating particulate filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain temperature-up control without causing wear of a clutch or poorer drivability with a gear position kept in the neutral range on idling stop of a vehicle equipped with a mechanical automatic transmission, and thus to efficiently continue forced regeneration of a particulate filter.SOLUTION: In a method for regenerating the particulate filter 6 in the state of idling stop of a vehicle equipped with a mechanical automatic transmission 13, the temperature-up control to raise exhaust temperature by performing a higher rotating speed of a diesel engine 1 than in usual idling is permitted when a foot brake is actuated in the state of stop of a vehicle with zero vehicle speed and a clutch is in the completely-off state even with the gear position of a shift lever of the mechanical automatic transmission 13 being kept in the drive range. The forced regeneration of the particulate filter 6 is permitted when the exhaust temperature is raised up to the required temperature in the temperature-up control.

Description

  The present invention relates to a particulate filter regeneration method and apparatus.

  Particulate matter (particulate matter) discharged from a diesel engine is mainly composed of soot made of carbonaceous matter and SOF content (Soluble Organic Fraction) made of high-boiling hydrocarbon components. The composition contains a small amount of sulfate (mist-like sulfuric acid component). As a measure to reduce this type of particulates, a particulate filter is installed in the middle of the exhaust pipe through which the exhaust gas flows. It has been done conventionally.

  This type of particulate filter has a porous honeycomb structure made of ceramics such as cordierite, and the inlets of each flow path 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. Although it is necessary to regenerate, in an ordinary diesel engine operation state, there are few opportunities to obtain an exhaust temperature high enough for the particulates to self-combust.

  For this reason, for example, an oxidation catalyst obtained by adding an appropriate amount of a rare earth element such as cerium to a material in which platinum is supported on alumina is integrally supported on a particulate filter and collected in the particulate filter. The oxidation reaction of the particulates is promoted by the oxidation catalyst to lower the ignition temperature, so that the particulates can be burned and removed even at an exhaust temperature lower than that of the prior art.

  However, even in such a case, in the operation region where the exhaust temperature is low, the trapped amount exceeds the processing amount of the particulate, so if the operation state at the low exhaust temperature continues, the particulates There is a possibility that the particulate filter will fall into an over-collected state without regenerating the filter well, and the particulate filter is forcibly heated when the accumulated amount of particulates has increased. It is necessary to incinerate the curate.

  More specifically, a flow-through type oxidation catalyst is provided in front of the particulate filter, and fuel is added upstream from the oxidation catalyst, and the added fuel is oxidized by the oxidation catalyst in front of the particulate filter. The exhaust gas heated by the reaction heat is introduced into the particulate filter, the catalyst bed temperature is raised to burn out the particulate, and the particulate filter is regenerated.

  In addition, as a specific means for executing this kind of fuel addition, post injection is added at a non-ignition timing later than the compression top dead center following the main injection of fuel performed near the compression top dead center. The fuel can be added to the exhaust gas.

  Conventionally, when the amount of accumulated particulates in the particulate filter exceeds the allowable amount and forced regeneration is necessary, forced regeneration is automatically performed during traveling. For buses, trucks, etc. that operate on a congested route, etc., even if forced regeneration of the particulate filter is automatically applied during traveling, there may be a case where the vehicle is stopped before the regeneration is completed.

  If the vehicle is in an idling state where the vehicle is stopped, the exhaust temperature will drop significantly and the regeneration of the particulate filter will slow down, so the gear position must be in the neutral range when the vehicle is idling. It is considered that the regeneration of the particulate filter can proceed well by performing forced regeneration while performing idle-up that increases the engine speed from normal idling as temperature rise control that raises the exhaust temperature. Yes.

  The method for forcibly regenerating this type of particulate filter is also described in the following Patent Document 1 and Patent Document 2 by the same applicant as the present invention.

JP 2003-83139 A JP 2003-155913 A

  However, for large vehicles such as buses and trucks, a mechanical automatic transmission has been adopted in which the starting operation and the shifting operation can be mechanically performed by a shift unit (for example, motor type, hydraulic type, pneumatic type). There are many cases in which this type of mechanical automatic transmission is used, so it is often the case that the shift lever of the automatic transmission is not shifted from the drive range to the neutral range simply by depressing the foot brake when stopping. If the temperature rise control is allowed only when the gear position is set to the neutral range in the idling state where the vehicle is stopped, the temperature rise control is difficult to perform, and it takes time to complete the regeneration of the particulate filter. There was concern.

  Therefore, even when the shift lever of the mechanical automatic transmission is in the drive range, it is considered to adopt a method of allowing the temperature increase control if the foot brake is stopped and the vehicle is stopped. In such a mechanical automatic transmission, the clutch engagement / disengagement operation accompanying the start operation and the shift operation is also automatically performed by the auto clutch mechanism. It is unclear whether the clutch is completely disconnected or half-clutch, and if idle-up is executed in the half-clutch state, clutch wear and drivability That could lead to a worsening of the vehicle (a sudden increase in starting power unintended by the driver), and so far temperature control is permitted in the drive range. Adoption has been shelved.

  The present invention has been made in view of the above circumstances, and temperature rise control without causing deterioration of the clutch and drivability while keeping the gear position in the neutral range when the vehicle equipped with the mechanical automatic transmission is stopped. The purpose is to enable the forced regeneration of the particulate filter to be continued efficiently.

  The present invention relates to a method for regenerating a particulate filter under a condition in which a vehicle employing a mechanical automatic transmission is stopped in an idling state, and a gear position of a shift lever of the mechanical automatic transmission is in a drive range. However, when the foot brake is depressed and the clutch is completely disengaged when the vehicle speed is zero and the clutch is completely disengaged, the temperature increase control for allowing the engine speed to be increased to increase the exhaust temperature from that during normal idling is permitted. The forced regeneration of the particulate filter is permitted when the exhaust gas temperature rises to a required temperature by temperature rise control.

  Thus, in this way, the temperature increase control in the drive range that has been forgotten so far is permitted when the foot brake is depressed and the clutch is in a completely disconnected state while the vehicle speed is zero. Therefore, even if the driver does not shift the shift lever of the automatic transmission from the drive range to the neutral range simply by depressing the foot brake when the vehicle is idling, the engine speed is higher than that during normal idling. It is possible to perform forced regeneration of the particulate filter while increasing the exhaust temperature by increasing the number, and thereby it is possible to continue the forced regeneration of the particulate filter efficiently.

  In this case, since the foot brake is depressed and the clutch is completely disconnected while the vehicle speed is zero, even if the engine speed increases from normal idling due to the temperature rise control, the clutch Thus, the wear of the vehicle and the deterioration of drivability (rapid increase of the starting force unintended by the driver) are surely avoided, and the sudden start of the vehicle is also surely avoided.

  Furthermore, when the particulate filter regeneration method of the present invention is specifically implemented, for example, an apparatus for regenerating the particulate filter under a condition that a vehicle employing a mechanical automatic transmission is stopped in an idling state. A catalyst regeneration type particulate filter provided in the middle of the exhaust pipe with an oxidation catalyst, a fuel addition means for adding fuel to the exhaust gas upstream of the oxidation catalyst, and a vehicle speed sensor for detecting the vehicle speed A clutch stroke sensor for measuring the clutch stroke to detect a completely disengaged state of the clutch, a brake switch for detecting foot brake depression, and a neutral switch for detecting the gear position of the shift lever of the mechanical automatic transmission Increase the engine speed and increase the exhaust temperature compared to normal idling. A control device for instructing fuel addition to the fuel addition means while performing control and forcibly regenerating the particulate filter, and even if the neutral switch detects the drive range, the vehicle speed sensor reduces the speed to zero. When the brake switch detects that the foot brake has been depressed and the clutch stroke sensor detects a completely disconnected state of the clutch, the temperature rise control is permitted and the exhaust temperature rises to the required temperature by the temperature rise control. Then, it is preferable to configure the control device so that forced regeneration of the particulate filter can be permitted.

  According to the particulate filter regeneration method and apparatus of the present invention described above, the clutch position and the drivability are not deteriorated while the gear position is kept in the neutral range when the vehicle equipped with the mechanical automatic transmission is stopped. The temperature rise control can be realized, and an excellent effect that the forced regeneration of the particulate filter can be continued efficiently can be achieved.

It is the schematic which shows an example of the form which implements this invention. It is sectional drawing which shows the detail of the particulate filter of FIG. FIG. 2 is a perspective view showing a part of the oxidation catalyst of FIG.

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

  FIG. 1 shows an example of an embodiment for carrying out the present invention. In FIG. 1, reference numeral 1 shows a diesel engine of a vehicle adopting a mechanical automatic transmission 13 capable of mechanically performing a start operation and a shift operation by a shift unit. In the middle of the exhaust pipe 4 through which the exhaust gas 3 discharged from the diesel engine 1 through the exhaust manifold 2 circulates, a catalyst regeneration type particulate filter 6 having an oxidation catalyst 5 in the previous stage is a filter case 7. It is held and intervened by.

  This particulate filter 6 has a porous honeycomb structure made of ceramic as shown in an enlarged view in FIG. 2, and the inlets of the respective flow paths 6a partitioned in a lattice pattern are alternately sealed, and the inlets are sealed. The outlet of the flow path 6a that is not made is sealed so that only the exhaust gas 3 that has permeated through the porous thin wall 6b that defines each flow path 6a is discharged downstream. It has become. Incidentally, the oxidation catalyst 5 provided in the preceding stage of the particulate filter 6 has a flow-through structure as shown in FIG.

  A pressure sensor 8 is provided on the inlet side of the filter case 7, and a pressure signal 8a of the pressure sensor 8 is input to a control device 9 constituting an engine control computer (ECU: Electronic Control Unit). In this control device 9, based on the pressure signal 8a from the pressure sensor 8, the pressure difference between the inlet side and the outlet side of the particulate filter 6 (the pressure loss corresponding to the operating region on the outlet side is initialized in advance. ) Is calculated, and the accumulated amount of particulates in the particulate filter 6 is estimated based on the pressure difference.

  That is, in the example shown here, the accumulation amount estimation means for estimating the accumulation amount of the particulates in the particulate filter 6 is constituted by the pressure sensor 8 and the control device 9. There are various methods for estimating the amount of accumulated particulates. For example, the basic generation amount of particulates based on the current operating state of the diesel engine 1 is estimated, and this basic generation amount is calculated. Multiply the correction factors considering various conditions related to the generation of particulates and subtract the particulate processing amount in the current operation state to obtain the final generation amount, and accumulate this final generation amount every moment It is also possible to estimate the amount of particulate deposition.

  Further, since the control device 9 shown here also serves as an engine control computer, it is also responsible for control relating to fuel injection. More specifically, the accelerator opening is determined by the load of the diesel engine 1. As shown in FIG. 2, fuel is supplied to each cylinder of the diesel engine 1 on the basis of the accelerator opening signal 11a from the accelerator sensor 11 (load sensor) detected as follows and the rotational speed signal 12a from the rotational sensor 12 that detects the engine rotational speed of the diesel engine 1. The fuel injection signal 10a is output to the fuel injection device 10 that injects fuel.

  The fuel injection device 10 is composed of a plurality of injectors provided for each cylinder, and the solenoid valves of these injectors are appropriately controlled to open by the fuel injection signal 10a, so that the fuel injection timing ( The valve opening timing) and the injection amount (valve opening time) are appropriately controlled.

  On the other hand, in the control device 9, the fuel injection signal 10a in the normal mode is determined based on the accelerator opening signal 11a and the rotation speed signal 12a. On the other hand, when the forced regeneration of the particulate filter 6 is to be performed, Mode is switched to the regeneration mode, and fuel injection with an injection pattern in which post-injection is performed at a non-ignition timing later than the compression top dead center following the main injection of fuel performed near the compression top dead center (crank angle 0 °). The signal 10a is determined.

  That is, in this embodiment, the fuel injection device 10 functions as a fuel addition means for forced regeneration of the particulate filter 6, and as described above, the compression top dead center following the main injection. When post-injection is performed at a later timing of non-ignition, unburned fuel (mainly HC: hydrocarbon) is added to the exhaust gas 3 by this post-injection, and this unburned fuel becomes particulate. The oxidation reaction is performed on the oxidation catalyst 5 at the front stage of the filter 6, and the catalyst bed temperature rises due to the reaction heat, and the particulates in the particulate filter 6 are burned and removed.

  Then, the control device 9 determines whether or not the accumulated amount of the particulates estimated based on the pressure signal 8a from the pressure sensor 8 exceeds the allowable amount. The combustion injection control is switched from the normal mode to the regeneration mode after the inlet exhaust temperature of the particulate filter 6 becomes a predetermined temperature or higher based on the temperature signal 16a from the sensor 16, and the particulate filter 6 is forced by automatic control. Playback is started.

  In addition, when the particulate filter 6 is forcibly regenerated under the condition that the vehicle is stopped in the idling state, the compression top dead center (in order to increase the rotational speed from the normal idling time when the condition described in detail below is satisfied. The temperature increase control for increasing the injection amount per one injection performed near the crank angle (0 °) is permitted, and the fuel injection signal 10a for instructing the idle increase is output.

  That is, when the particulate filter 6 is forcibly regenerated in an idling state where the vehicle is stopped, the temperature and flow rate of the exhaust gas 3 are too low to perform good combustion removal of the particulates. By increasing the injection amount per one time, the rotational speed is increased from that during normal idling, thereby increasing the amount of energy input and raising the temperature and flow rate of the exhaust gas 3 to a level suitable for forced regeneration.

  In permitting such temperature increase control, the control device 9 determines the gear position based on the detection signal 17a from the neutral switch 17 that detects the gear position of the shift lever of the mechanical automatic transmission 13, and the gear position is determined. In the neutral range, the temperature rise control is permitted after confirming the foot brake depression based on the detection signal 14a from the brake switch 14.

  In this embodiment, the clutch that measures the clutch stroke to detect the complete disengagement state of the clutch and outputs the detection signal 15a to the control device 9 so that the temperature rise control can be realized even in the drive range. A stroke sensor 15 is newly provided, and when the existing vehicle speed sensor 18 detects zero speed, the brake switch 14 detects the depression of the foot brake, and the clutch stroke sensor 15 detects the complete disengagement state of the clutch, Even if the neutral switch 17 detects the drive range, the temperature rise control is permitted.

  When it is confirmed based on the temperature signal 16a from the temperature sensor 16 that the exhaust gas temperature has risen to the required temperature by the temperature increase control, the forced regeneration of the particulate filter 6 is permitted and the combustion injection control starts from the normal mode. Switching to the regeneration mode, post injection is started on the diesel engine 1 side.

  In the control device 9 in this embodiment, it is determined whether or not the vehicle is idling based on the detection signals 11a, 12a, and 18a from the accelerator sensor 11, the rotation sensor 12, and the vehicle speed sensor 18 described above. More specifically, the accelerator sensor 11 confirms that the accelerator is off (load is zero), the rotation sensor 12 confirms that the engine speed is within a relatively low predetermined rotational speed range, and the vehicle speed sensor 18 When it is confirmed that the vehicle speed is zero, it is determined that the current driving state is the idling state.

  Thus, in this way, the temperature rise control in the drive range that has been deferred until now, the vehicle speed sensor 18 detects zero speed, the brake switch 14 detects the depression of the foot brake, and the clutch Since the stroke sensor 15 is permitted when the clutch is completely disengaged, the driver does not shift the shift lever of the automatic transmission from the drive range to the neutral range simply by depressing the foot brake when the vehicle is idling. Even so, it is possible to forcibly regenerate the particulate filter 6 while raising the exhaust temperature by increasing the rotational speed of the diesel engine 1 from the normal idling by temperature increase control. Reproduction can be continued efficiently.

  At this time, since the foot brake is depressed and the clutch is completely disengaged while the vehicle speed is zero, even if the rotational speed of the diesel engine 1 increases from the normal idling due to the temperature rise control. In addition, clutch wear and deterioration of drivability (a sudden increase in starting force unintended by the driver) are surely avoided, and a sudden start of the vehicle is also reliably avoided.

  Therefore, according to the above embodiment, when the vehicle equipped with the mechanical automatic transmission 13 is stopped at idling, the temperature rise control is realized without causing the wear of the clutch or the deterioration of the drivability while keeping the gear position in the neutral range. The forced regeneration of the particulate filter 6 can be continued efficiently.

  The particulate filter regeneration method and apparatus according to the present invention is not limited to the above-described embodiment, but employs a fuel injection device as the fuel addition means, and the main fuel that is used near the compression top dead center. Fuel is added to the exhaust gas by post-injection at a non-ignition timing that is later than the compression top dead center following injection, but fuel is added to the appropriate position of the exhaust pipe (or an exhaust manifold). As a matter of course, the injector may be mounted through, and fuel may be directly injected into the exhaust gas by the injector, and various changes can be made without departing from the scope of the present invention. is there.

1 Diesel engine (engine)
Reference Signs List 3 exhaust gas 4 exhaust pipe 5 oxidation catalyst 6 particulate filter 9 control device 10 fuel injection device (fuel addition means)
13 Mechanical automatic transmission 14 Brake switch 15 Clutch stroke sensor 16 Temperature sensor 17 Neutral switch 18 Vehicle speed sensor

Claims (2)

  This is a method of regenerating a particulate filter under the condition that a vehicle employing a mechanical automatic transmission is stopped in an idling state, and the vehicle speed does not change even if the gear position of the shift lever of the mechanical automatic transmission is in the drive range. When the foot brake is depressed and the clutch is completely disengaged when the vehicle is at a zero stop, the temperature increase control for increasing the engine speed and increasing the exhaust temperature from the normal idling is permitted. A particulate filter regeneration method, wherein forced regeneration of the particulate filter is permitted when the exhaust gas temperature rises to a required temperature.   A device for regenerating a particulate filter under the condition that a vehicle employing a mechanical automatic transmission is stopped in an idling state, comprising a catalyst regeneration type particulate filter provided in the middle of an exhaust pipe with an oxidation catalyst provided in the preceding stage A fuel addition means for adding fuel into the exhaust gas upstream from the oxidation catalyst, a vehicle speed sensor for detecting the vehicle speed, a clutch stroke sensor for measuring the clutch stroke and detecting a completely disconnected state of the clutch, Brake switch that detects the foot brake depression, neutral switch that detects the gear position of the shift lever of the mechanical automatic transmission, and temperature increase control that raises the engine speed and raises the exhaust gas temperature during normal idling Instructing the fuel addition means to add fuel while performing A control device for performing regeneration, and even if the neutral switch detects a drive range, the vehicle speed sensor detects zero speed, the brake switch detects foot brake depression, and the clutch stroke sensor The control device is configured to allow the particulate filter to be forcibly regenerated when the exhaust gas temperature rises to a required temperature by the temperature increase control when the complete cut state is detected. A particulate filter regeneration device characterized by the above.

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