JP3900145B2 - Engine exhaust purification system - Google Patents

Description

  The present invention relates to an exhaust emission control device for an engine provided with a filter for collecting particulates (floating particulate matter such as black smoke) in exhaust gas in an exhaust passage.

  When the filter is provided in the exhaust passage of the engine, it is necessary to regenerate the filter by burning the fine particles when the accumulated amount of fine particles exceeds a predetermined value. With regard to this regeneration, there is known one in which a warning lamp is turned on when the accumulated amount of particulates in the filter exceeds a predetermined value, and the driver is urged to stop the vehicle and perform manual regeneration of the filter. (See Patent Document 1). In this manual regeneration, when the manual regeneration switch is turned on while the vehicle is stopped, the accelerator lever of the fuel injection pump of the engine reaches a predetermined opening, the engine speed increases, and the exhaust gas downstream of the filter is exhausted. The throttle valve provided in the passage is operated to restrict the exhaust passage, thereby increasing the exhaust temperature and raising the temperature of the filter.

Further, in a fuel supply system that stores high-pressure fuel pumped from a fuel pump in a common rail and distributes fuel from the common rail to a fuel injection valve provided in each cylinder of the vehicle engine, the common rail is detected by a fuel pressure sensor. It is known that when a state in which a differential pressure of a certain value or more between the fuel pressure (fuel pressure) and the target fuel pressure continues for a predetermined time, it is determined that the fuel pressure control valve of the common rail has failed and the engine operating range is limited. (See Patent Document 2).
Japanese Patent Laid-Open No. 04-086319 JP 2000-161171 A

  By the way, when the engine speed is increased and the filter is manually regenerated while the vehicle is stopped, the differential pressure between the fuel pressure detected by the fuel pressure sensor of the fuel supply system and the target fuel pressure increases. If this is the case, it can be determined that an abnormality has occurred in the fuel supply system or the fuel pressure sensor. Accordingly, in that case, it is conceivable to reduce the engine speed to the idle speed.

  However, if the engine speed is reduced during the manual regeneration, the amount of exhaust gas flowing into the filter is suddenly reduced. As a result, the temperature of the filter is rapidly increased, which may cause the filter to melt. On the other hand, if manual regeneration is continued as it is when the differential pressure becomes large, a fatal failure of the fuel supply system or the like may occur, or the engine body may be adversely affected.

  Therefore, an object of the present invention is to take measures against the fuel pressure abnormality during the manual regeneration described above.

  The present invention addresses the above problem by damaging the filter by continuing the manual regeneration within a range that does not adversely affect the fuel supply system even if a fuel pressure abnormality occurs during the manual regeneration. I was able to avoid it.

That is, the present invention includes a common rail that stores high-pressure fuel that is pumped from a fuel pump, and a fuel supply system that distributes and supplies the fuel accumulated in the common rail to fuel injection valves provided in each cylinder of a vehicle engine;
Fuel pressure detection means for detecting the fuel pressure of the fuel supply system;
Fuel pumping amount control means for controlling the fuel pumping amount of the fuel pump based on the fuel pressure detected by the fuel pressure detecting means so that the fuel pressure of the fuel supply system becomes a target fuel pressure corresponding to the operating state of the engine;
An abnormality that determines that the fuel supply system or the fuel pressure detection means is abnormal when the fuel pressure detected by the fuel pressure detection means is higher than the target fuel pressure by a predetermined pressure H or higher or lower than a predetermined pressure L or higher. A determination means;
An engine exhaust gas purification device comprising an abnormality time limiting means for limiting fuel injection by the fuel injection valve when an abnormality determination is made by the abnormality determination means,
A filter provided in the exhaust passage of the engine for collecting particulates in the exhaust gas;
Stop state detection means for detecting the stop state of the vehicle;
A manual regeneration switch for manually starting filter regeneration for burning the particulates collected in the filter;
Based on the detection signal from the stop state detection means and the signal from the manual regeneration switch, when both the condition that the vehicle is stationary and the condition that the manual regeneration switch is turned on are established, Manual regeneration means for increasing the engine speed by increasing the fuel injection amount by the fuel injection valve so as to reach a predetermined target engine speed to burn the particulates collected in the filter;
Threshold setting means for setting the predetermined pressure H on the high pressure side for the abnormality determination to be larger at the time of manual regeneration of the filter than at the time of manual regeneration and non-manual regeneration having the same target fuel pressure. It is characterized by being.

  Therefore, in the engine exhaust gas purification apparatus, when the manual regeneration switch is turned on while the vehicle is stopped, the manual regeneration means works to increase the fuel injection amount, thereby increasing the engine speed. Filter regeneration is performed.

  Thus, at the time of the manual regeneration, the predetermined pressure H on the high pressure side for determining the fuel pressure abnormality is larger than that at the time of non-manual regeneration, so that the abnormality of the fuel supply system or the fuel pressure detecting means may be a slight abnormality on the high pressure side. For example, unlike the non-manual regeneration, the abnormality determination is not made and the manual regeneration is continued. In other words, when the high pressure abnormality is slight, the abnormality limiting means is not operated to restrict the fuel injection, thereby preventing an abnormal increase in the filter temperature due to a decrease in the engine speed.

  In addition, as described above, at the time of manual regeneration, the predetermined pressure H on the high pressure side for abnormality determination only increases, and when the fuel pressure becomes higher than the predetermined pressure H, the abnormality limiting means works and fuel injection by the fuel injection valve is performed. Due to the limitations, serious damage to the fuel supply system and engine can be avoided.

  Regarding the determination criterion for the fuel pressure abnormality, not only the high-pressure side predetermined pressure H but also the low-pressure side predetermined pressure L can be made larger during manual regeneration than during non-manual regeneration.

  Preferably, the target engine speed of the manual regeneration means is set to a low speed or medium speed rotational range that is higher than the idle speed, and the threshold setting means includes a predetermined pressure H and a low pressure on the high pressure side during the manual regeneration. A predetermined pressure L on the high pressure side is set to be larger than a predetermined pressure L on the high pressure side and a predetermined pressure L on the low pressure side during non-manual regeneration with the same target fuel pressure as the manual regeneration, and the predetermined pressure on the high pressure side. The degree of increasing H is larger than the degree of increasing the predetermined pressure L on the low pressure side.

  In other words, when the manual regeneration of the filter is executed in the low speed or medium speed range of the engine, the target fuel pressure of the fuel supply system is not so high. Therefore, even if the fuel pressure detected by the fuel pressure detection means during manual regeneration is slightly higher than the target fuel pressure, it does not lead to a serious failure of the fuel supply system or the engine. Therefore, as described above, the degree of increasing the high pressure side predetermined pressure H during manual regeneration can be made larger than the degree of increasing the low pressure side predetermined pressure L. This makes it possible to continue the manual regeneration without causing a serious accident in the fuel supply system or the like during the manual regeneration, which is advantageous for preventing the filter from being damaged.

  On the other hand, when the fuel pressure detected by the fuel pressure detecting means is lower than the target fuel pressure, there is a possibility that fuel has leaked. Therefore, for the predetermined pressure L on the low pressure side, during manual regeneration and during non-manual regeneration It is preferable not to increase the difference.

  The restriction of fuel injection when the abnormality determination is made by the abnormality determination means during the manual regeneration may be to make the fuel injection amount zero, but from the viewpoint of minimizing the influence on the filter, the engine rotation It is more preferable to reduce the fuel injection amount so that the number becomes the idling speed.

  As described above, according to the present invention, an abnormality occurs when the fuel pressure detected by the fuel pressure detecting means of the fuel supply system becomes higher than the target fuel pressure by a predetermined pressure H or lower than a predetermined pressure L. In an engine in which determination is made and fuel injection by the fuel injection valve is limited, the high pressure for fuel pressure abnormality determination is determined at the time of manual regeneration in which the engine speed is increased and the filter is regenerated while the vehicle is stopped. Since the predetermined pressure H on the side is higher than that during non-manual regeneration, manual regeneration will continue even if there is a slight high-pressure abnormality during manual regeneration, resulting in a serious accident in the fuel supply system, engine, etc. Without incurring melting, it is possible to prevent melting damage due to abnormal temperature rise of the filter.

  In addition, the target engine speed during manual regeneration is set to a low or medium speed range, and during manual regeneration, the high pressure side for determining fuel pressure abnormality is greater than during non-manual regeneration where the target fuel pressure is the same as during manual regeneration. If the predetermined pressure H and the predetermined pressure L on the low-pressure side are increased and the degree of increasing the predetermined pressure H is larger than the degree of increasing the predetermined pressure L, a serious accident may be caused in the fuel supply system or the like. Therefore, it is more advantageous to continue the manual regeneration and prevent the filter from being damaged.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  In the engine exhaust gas purification apparatus shown in FIG. 1, 1 is a multi-cylinder diesel engine of a vehicle (only one cylinder is shown in FIG. 1), 2 is its intake passage, and 3 is its exhaust passage. A deep dish combustion chamber 5 is formed on the top surface of the piston 4 of the engine 1. The cylinder head of the engine 1 is provided with a fuel injection valve 7 so that fuel can be directly injected into the in-cylinder combustion chamber 5.

  In the intake passage 2, the air cleaner 9, the air flow sensor 10, the blower 11 a of the turbocharger 11, the intercooler 12, the intake throttle valve 13, the intake temperature sensor 14, and the intake pressure are sequentially arranged from the upstream side to the downstream side. A sensor 15 is provided. In the exhaust passage 3, a turbine 11 b of the turbocharger 11, an oxidation catalyst 16, and a DPF (diesel particulate filter) 17 that collects particulates in the exhaust gas are arranged in order from the upstream side to the downstream side. ing. Exhaust pressure sensors 18 and 19 are disposed upstream and downstream of the DPF 17. The DPF 17 carries an oxidation catalyst at a site upstream thereof.

  Further, the upstream side of the exhaust passage 3 with respect to the turbine 11b and the downstream side of the intake passage 2 with respect to the intake pressure sensor 15 are connected by an exhaust gas recirculation passage 21 for returning a part of the exhaust gas to the intake system. . In the middle of the exhaust gas recirculation passage 21, a negative pressure actuator type exhaust gas recirculation amount control valve (EGR valve) 22 and a cooler 23 for cooling the exhaust gas with engine coolant are disposed.

  Fuel in a fuel tank (not shown) is supplied to the fuel injection valve 7 by a fuel supply pipe 28 via a fuel filter 25, a high-pressure fuel pump 26, and a common rail 27 as pressure accumulating means, and is supplied to the fuel tank by a fuel return pipe 29. Returned. That is, the high pressure fuel pumped from the fuel pump 26 is stored in the common rail 27, and the fuel stored in the common rail 27 is distributed and supplied to the fuel injection valves 7 of the cylinders of the engine 1. The fuel injection valve 7, the fuel tank, the fuel filter 25, the high pressure fuel pump 26, the common rail 27, the fuel supply pipe 28, and the fuel return pipe 29 constitute a fuel supply system. The common rail 27 is provided with a fuel pressure sensor 30 for detecting the fuel pressure in the common rail.

  31 is a water temperature sensor that detects the engine water temperature, 32 is a crank angle sensor that detects the engine speed, 33 is a sensor that detects the exhaust gas temperature flowing into the oxidation catalyst 16, 34 is a sensor that detects the exhaust gas temperature flowing into the DPF 17, Reference numeral 35 denotes a sensor for detecting the temperature of exhaust gas flowing out from the DPF 17.

  Then, in order to regenerate the DPF 17 by burning the fine particles when the amount of the fine particles collected in the DPF 17 increases, the ECU (engine control unit) 40 using the microcomputer shown in FIG. Fuel injection control by the fuel injection valve 7 is executed.

  That is, the ECU 40 is provided with a forced regeneration means 41 for regenerating the DPF 17 while the vehicle is running, and a manual regeneration means 42 for regenerating the DPF 17 while the vehicle is stopped, and further a warning lamp for prompting the occupant to perform manual regeneration. 43, a target fuel pressure setting means 45, a fuel pumping amount control means 46, an abnormality determination means 47, an abnormality limiting means 48, and a threshold setting means 49 are provided.

  Thus, for these means 41, 42, 44 to 49, exhaust pressure sensors 18, 19, fuel pressure sensor 30, crank angle sensor 32, accelerator for detecting the accelerator opening of the engine (depressing amount of the accelerator pedal). Signals from an opening sensor 51, a vehicle speed sensor 52, a shift range (select lever position) sensor 53 of the automatic transmission, a manual regeneration switch 54, and the like are input to the ECU 40.

  The exhaust pressure sensors 18 and 19 constitute a fine particle amount detecting means for detecting a parameter value related to the fine particle amount collected by the DPF 17. That is, the amount of fine particles accumulated in the DPF 17 is detected based on the differential pressure between the exhaust pressures detected by both the sensors 18 and 19, and the larger the differential pressure, the larger the accumulated amount is determined. be able to.

  The accelerator opening sensor 51 is used to determine the engine load, and the accelerator opening sensor 51 and the crank angle sensor 32 detect the parameter values related to the engine operating state (engine load and engine speed). The operating state detecting means is configured. The accelerator opening sensor 51, the vehicle speed sensor 52, and the shift range sensor 53 constitute vehicle driving state detection means (stop state detection means) that detects parameter values related to the driving state of the vehicle.

  The warning lamp 43 and the manual switch 54 are provided on the instrument panel of the vehicle.

  The forced regeneration means 41 determines that the amount of particulates collected by the DPF 17 is greater than or equal to a predetermined threshold based on detection signals from the exhaust pressure sensors 18 and 19, and the vehicle is an oxidation catalyst based on the output of the vehicle speed sensor 52. When it is determined that the vehicle is in an operating state that activates 16 (a predetermined vehicle speed (for example, 50 km / h or more)), the forced regeneration of the DPF 17 is executed. That is, the forced regeneration means 41 regenerates the filter 17 by executing sub-injection in which fuel is injected in the expansion stroke after the main injection in which fuel is injected near the top dead center of the compression stroke to generate engine output.

  The main injection control is performed by setting the main injection amount and the main injection timing with reference to a map that is preset and electronically stored based on the engine speed and the engine load. And correction based on intake air temperature and the like.

  The sub-injection control is also performed by setting the sub-injection amount and sub-injection timing with reference to a map that is preset and electronically stored based on the engine speed and the engine load. By this sub-injection, unburned fuel or partially oxidized fuel is supplied to the oxidation catalyst 16, the temperature of exhaust gas flowing into the DPF 17 is increased by the catalytic reaction heat in the oxidation catalyst 16, and the temperature of the DPF 17 is burned so that the particulates burn. To rise.

  The sub-injection amount is basically set such that the sub-injection amount increases as the engine load decreases and as the engine speed decreases. This is because the lower the engine load and the lower the engine speed, the lower the exhaust gas temperature due to main injection and the smaller the amount of exhaust gas. The sub-injection timing is such that the engine load is within the range of 50 ° CA to 120 ° CA in the ATDC (after the top dead center of the compression stroke) in order to discharge the injected fuel by being slightly thermally decomposed so as to be easily burned by the oxidation catalyst 16. The higher the engine speed is, the slower the engine speed is set.

  Based on outputs from the accelerator opening sensor 51, the vehicle speed sensor 52, and the shift range sensor 53, the manual regeneration means 42 has an accelerator opening of zero, a vehicle speed of zero, and a select lever in the P (parking) range. Alternatively, when the three conditions of being in the N (neutral) range are satisfied, it is determined that the vehicle is in a stopped state, and when it is determined that the manual regeneration switch 54 is turned on, the manual regeneration of the DPF 17 is executed.

  That is, the manual regeneration means 42 sets the target engine speed to a low speed or medium speed (for example, 1500 to 2000 rpm) higher than the idle speed, and the fuel injection amount so that the engine speed becomes the target engine speed. Is feedback controlled (the main injection amount is increased). By increasing the main injection amount, the exhaust gas temperature is raised, the temperature of the DPF 17 is raised, and the fine particles of the DPF 17 are burned.

  Regarding the detection of the stop state, it is determined that the stop state is only when the vehicle speed is zero, or the condition that the vehicle speed is zero, and the condition that the accelerator opening is zero or the select lever is in either the P range or the N range. When the condition is established, it may be determined that the vehicle is stopped.

  The warning means 44 is for warning the vehicle occupant that manual regeneration of the DPF 17 is necessary, and the amount of particulates collected in the DPF 17 based on detection signals from the exhaust pressure sensors 18 and 19 is predetermined. When it is determined that the value is equal to or greater than the threshold value α, the warning lamp 43 is turned on. The threshold value α is set to a value higher than the threshold value for forced regeneration.

  The target fuel pressure setting means 45 is configured so that the fuel injection valve 7 forms an appropriate fuel spray according to the operating state of the engine so as not to cause inconveniences such as deterioration of fuel consumption and emission. The target fuel pressure is set based on In this embodiment, the optimum values corresponding to the engine speed and the engine load are experimentally obtained in advance and electronically recorded as a map, and the values corresponding to the current engine speed and the engine load are read from the table. It has become. In this case, as schematically shown in FIG. 3, it is determined that the target fuel pressure increases as the engine speed increases and as the engine load increases.

  The fuel pressure feed amount control means 46 is a high-pressure fuel from the fuel pump 26 to the common rail 27 according to the difference between the detected value of the common rail pressure and the target fuel pressure so that the common rail pressure detected by the fuel pressure sensor 30 becomes the target fuel pressure. Feedback control of the amount of pumping. Specifically, the fuel pump 26 is provided with an electromagnetic adjustment valve that relieves the fuel so that the fuel is not pumped to the common rail 27, and this adjustment valve is controlled in accordance with a value detected by the fuel pressure sensor 30.

  The abnormality determination means 47 is used when the detected value of the fuel pressure sensor 30 immediately before fuel injection in each combustion cycle of the engine is higher than the target fuel pressure by a predetermined pressure H (difference between the target fuel pressure and the fuel pressure upper limit value) or When the fuel pressure becomes lower than the target fuel pressure by a predetermined pressure L (difference between the target fuel pressure and the fuel pressure lower limit value) or more, it is determined that the fuel supply system or the fuel pressure sensor 30 is abnormal. In this case, if the detected value is higher than the fuel pressure upper limit value, for example, there may be an abnormality in the pressure regulator, the pressure limiter for discharging the fuel from the common rail 27, or the fuel pressure sensor, and the detected value exceeds the fuel pressure lower limit value. When it is low, there is an abnormality in these regulating valves and the like, and it is considered that fuel leaks from the fuel pipe.

  The abnormality limiting means 48 limits the fuel injection by the fuel injection valve 7 when an abnormality determination is made by the abnormality determination means 47. When the DPF 17 is being manually regenerated, the engine speed is idle. The fuel injection amount is decreased so that the rotational speed is reached.

  The threshold value setting means 49 for determining the fuel pressure abnormality is shown in FIG. 3 by a broken line with an upper limit value and a lower limit value of the fuel pressure during non-manual regeneration, and with an alternate long and short dash line with an upper limit value and a lower limit value of the fuel pressure during manual regeneration. As described above, the manual regeneration and the non-manual regeneration (the manual regeneration and the non-manual regeneration with the same target fuel pressure) are set differently. That is, during manual regeneration, the threshold setting unit 49 sets both the predetermined pressure H on the high pressure side and the predetermined value L on the low pressure side to be greater than those during non-manual regeneration, and the degree to which the predetermined value H on the high pressure side is increased. The predetermined value L on the low pressure side is set larger than the degree of increase.

  FIG. 4 shows the flow of the above-described manual regeneration control. In step S1 after the start, detection of the vehicle speed, accelerator opening and shift range by the sensors 51 to 53, detection of the common rail internal combustion pressure by the fuel pressure sensor 30 in step S2, In step S3, the exhaust pressure sensors 18 and 19 detect the differential pressure between the exhaust pressures before and after the DPF 17, and based on this differential pressure, the particulate accumulation amount of the DPF 17 is calculated in step S4.

  In subsequent step S5, it is determined whether or not the amount of accumulated particulates is equal to or larger than a predetermined threshold value α. When the amount of accumulated particulates is less than the threshold value α, the process returns. On the other hand, when it is equal to or larger than the threshold value α, the process proceeds to step S6, and the warning lamp 43 is turned on.

  In the following step S7, it is determined whether or not the manual regeneration switch 54 is turned on. If not turned on, the process returns. On the other hand, if turned on, the process proceeds to step S8, where the vehicle speed is zero. It is determined whether or not all three conditions that the accelerator is fully closed (the opening degree is zero) and the select lever is in the P range or the N range are satisfied. That is, the safety of whether or not the vehicle is completely stopped and manual regeneration may be executed is confirmed.

  When at least one of the three conditions is not satisfied, the process returns. On the other hand, when all the three conditions are satisfied, the process proceeds to step S9 to set the manual regeneration execution time T, and the timer value t is started to be counted at step S10. The timer value t is incremented by a predetermined value every time the control cycle proceeds. The manual regeneration execution time T may be set as a fixed time (for example, 10 to 20 minutes) or may be set according to the amount of deposition so that the time becomes longer as the amount of particulate deposition in the DPF 17 increases.

  In the following step S11, it is determined whether or not the execution time T is longer than the timer value t. If the execution time T is longer, the process proceeds to step S12 to set a threshold value for determining a fuel pressure abnormality. In this case, since manual regeneration, the high pressure side threshold value (predetermined pressure H) and the low pressure side threshold value (predetermined pressure L) are set so that the fuel pressure upper limit value and the fuel pressure lower limit value are the lines indicated by the one-dot chain line in FIG. Set.

  In a succeeding step S13, it is determined whether or not the differential pressure between the target fuel pressure and the detected value is equal to or higher than the high pressure side threshold value, or whether or not it is equal to or higher than the low pressure side threshold value. When the differential pressure is equal to or higher than the threshold value on either the high pressure side or the low pressure side, the process proceeds to step S14 and the manual regeneration is stopped. That is, the target engine speed is set to the idle speed. On the other hand, when the differential pressure is less than the high-pressure side threshold value and less than the low-pressure side threshold value (when it is between the fuel pressure upper limit value and the fuel pressure lower limit value indicated by the one-dot chain line in FIG. 3), the process proceeds to step S15. Perform playback. That is, the target engine speed is set to 1750 rpm and the main fuel injection amount is increased. As a result, the temperature of the exhaust gas flowing into the DPF 17 rises, and the fine particles collected in the DPF 17 burn.

  When the timer value t becomes equal to or longer than the manual regeneration execution time T in step S11, the process proceeds to step S16, the timer value t is returned to zero, and the manual regeneration is terminated. That is, the target engine speed is gradually decreased to the idle speed.

  As described above, since the high-pressure side threshold and the low-pressure side threshold for fuel pressure abnormality determination during manual regeneration of the DPF 17 are larger than those during non-manual regeneration, abnormality determination is not performed even if there is a slight fuel pressure abnormality. Manual regeneration continues. Therefore, the amount of exhaust gas flowing into the DPF 17 is not suddenly reduced by a slight abnormality in the fuel pressure, and the problem of melting damage due to an abnormal temperature rise of the DPF 17 is solved.

  In addition, the degree to which the high-pressure side threshold value for determining the fuel pressure abnormality during manual regeneration is greater than the degree to which the low-pressure side threshold value is increased, but the target engine speed is set to a low or medium engine speed range, and the common rail Since the internal pressure is not so high, even if the common rail internal combustion pressure becomes slightly higher than the target fuel pressure during manual regeneration, it does not lead to a serious failure of the fuel supply system. On the contrary, since the region where abnormality is determined at the time of manual regeneration becomes larger on the high pressure side, it is advantageous in continuing manual regeneration and preventing the DPF 17 from being melted.

  On the other hand, since the low-pressure side threshold value is not largely changed between manual regeneration and non-manual regeneration, the pressure in the common rail has decreased to about the same level as during non-manual regeneration even during manual regeneration. Sometimes fuel injection is limited (controlled to idle speed) and, for example, a serious accident caused by fuel leakage from the fuel supply system is avoided.

  Regarding manual regeneration, the main injection amount of fuel is increased so as to reach the target engine speed, and the intake throttle that reduces the intake amount flowing into the cylinder by the intake throttle valve, or the exhaust passage downstream of the DPF. The temperature of the DPF 17 may be increased quickly by providing a throttle valve to reduce the exhaust flow rate.

  Further, during the manual regeneration, the main injection amount may be increased, and the sub-injection in which fuel is injected in the expansion stroke (for example, near ATDC 50 ° CA) may be executed. By increasing the main injection amount, the exhaust gas temperature is raised to raise the temperature of the oxidation catalyst 16 to the activation temperature, and by executing sub-injection, the catalytic reaction heat in the oxidation catalyst 16 is used in the same way as in the case of forced regeneration. It burns the fine particles.

  Moreover, although the said embodiment is provided with the forced regeneration means 41, this invention is applicable also to the vehicle in which the forced regeneration means is not provided.

  In the above embodiment, the warning lamp 43 is turned on when the amount of collected particulate matter of the DPF 17 exceeds a predetermined threshold value. However, even when the lamp 43 is not turned on, the vehicle is voluntarily stopped and the manual regeneration switch is turned on. Manual regeneration may be started by operating 54.

  Moreover, although the said embodiment is a case where a filter is DPF, this invention is applicable also when trapping the particulates contained in the exhaust gas of a gasoline engine with a filter.

1 is a configuration diagram of an exhaust emission control device for an engine according to the present invention. It is a control block diagram of the apparatus. It is a graph which shows the target fuel pressure of a fuel supply system, the fuel pressure upper limit value for fuel pressure abnormality determination, and a fuel pressure lower limit value (at the time of a non-manual regeneration and a one-dot chain line at the time of manual regeneration). It is a manual regeneration control flowchart of the same device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Intake passage 3 Exhaust passage 5 In-cylinder combustion chamber 7 Fuel injection valve 16 Oxidation catalyst 17 DPF (filter)
18, 19 Exhaust pressure sensor 26 Fuel pump 30 Fuel pressure sensor 40 ECU
41 Forced regeneration means 42 Manual regeneration means 43 Warning lamp 44 Warning means 45 Target fuel pressure setting means 46 Fuel pressure feed control means 47 Abnormality judgment means 48 Abnormal limit means 49 Threshold setting means 51 Accelerator opening sensor 52 Vehicle speed sensor 53 Shift range sensor 54 Manual regeneration switch

Claims (3)

A fuel supply system that includes a common rail that stores high-pressure fuel that is pumped from a fuel pump, and that distributes fuel stored in the common rail to fuel injection valves provided in each cylinder of a vehicle engine;
Fuel pressure detection means for detecting the fuel pressure of the fuel supply system;
Fuel pumping amount control means for controlling the fuel pumping amount of the fuel pump based on the fuel pressure detected by the fuel pressure detecting means so that the fuel pressure of the fuel supply system becomes a target fuel pressure corresponding to the operating state of the engine;
An abnormality that determines that the fuel supply system or the fuel pressure detection means is abnormal when the fuel pressure detected by the fuel pressure detection means is higher than the target fuel pressure by a predetermined pressure H or higher or lower than a predetermined pressure L or higher. A determination means;
An engine exhaust gas purification device comprising an abnormality time limiting means for limiting fuel injection by the fuel injection valve when an abnormality determination is made by the abnormality determination means,
A filter provided in the exhaust passage of the engine for collecting particulates in the exhaust gas;
Stop state detection means for detecting the stop state of the vehicle;
A manual regeneration switch for manually starting filter regeneration for burning the particulates collected in the filter;
Based on the detection signal from the stop state detection means and the signal from the manual regeneration switch, when both the condition that the vehicle is stationary and the condition that the manual regeneration switch is turned on are established, Manual regeneration means for increasing the engine speed by increasing the fuel injection amount by the fuel injection valve so as to reach a predetermined target engine speed to burn the particulates collected in the filter;
Threshold setting means for setting the predetermined pressure H on the high pressure side for the abnormality determination to be larger at the time of manual regeneration of the filter than at the time of manual regeneration and non-manual regeneration having the same target fuel pressure. An exhaust emission control device for an engine. In claim 1,
The target engine speed of the manual regeneration means is set to a low or medium speed range higher than the idle speed,
The threshold setting means sets the predetermined pressure H on the high pressure side and the predetermined pressure L on the low pressure side during the manual regeneration to the predetermined pressure H on the high pressure side and the low pressure side on the non-manual regeneration with the same target fuel pressure as the manual regeneration. An engine exhaust gas purification apparatus, wherein the degree of increasing the predetermined pressure H on the high pressure side is greater than the degree of increasing the predetermined pressure L on the low pressure side. In claim 1 or claim 2,
The abnormal time limiting means reduces the fuel injection amount so that the engine rotational speed becomes an idle rotational speed when an abnormality determination is made by the abnormality determining means during the manual regeneration. Exhaust purification device.

Images