JP2005256820A - Engine exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent lowering of fuel economy due to wasteful fuel consumption, in an engine exhaust emission control device which activates an oxidation catalyst arranged in an exhaust emission passage on an upper stream-side than a filter by carrying out fuel sub-injection when forcedly regenerating a DPF. <P>SOLUTION: It is judged whether an own vehicle can travel so that it activates an oxidation catalyst, based on map information in a navigation system, or on road traffic information on a traffic jam. When such a traveling is not available, a forced regeneration of the filter is prohibited. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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 particulates when the amount of particulates collected by the filter exceeds a predetermined amount. With respect to this regeneration, an oxidation catalyst is disposed in the exhaust passage upstream of the filter, and fuel is injected into the cylinder immediately before the exhaust valve of the engine is closed, thereby supplying unburned fuel to the oxidation catalyst. It is known that the temperature of the filter is raised and fine particles are combusted by the oxidation reaction heat of the fuel in the oxidation catalyst (see Patent Document 1).
JP-A-8-42326

    In the forced regeneration technology of the above filter, the oxidation catalyst needs to be activated so that the unburned fuel can be oxidized and burned, but the exhaust gas temperature is low during normal driving of the vehicle, and the oxidation catalyst is in an inactive state. It is normal to be in Therefore, when the filter is regenerated, in order to activate the oxidation catalyst first, in the expansion stroke after the main injection of the fuel for obtaining the engine output, the sub-injection for injecting a small amount of fuel into the cylinder is performed for a predetermined time. It is necessary to increase the temperature of the exhaust gas by executing and discharging the sub-injected fuel by burning it in the cylinder, thereby increasing the temperature of the oxidation catalyst.

    By the way, the combustion of the sub-injected fuel in the cylinder depends on the temperature in the cylinder of the engine due to the combustion of the main injected fuel, in other words, on the running state of the vehicle. For example, when the vehicle is traveling at a low vehicle speed with a low engine load, or when the vehicle is frequently started and stopped, the in-cylinder temperature does not increase so much, and the sub-injected fuel may not burn efficiently in the cylinder. That is, if sub-injection is performed, the exhaust gas temperature does not always rise as expected and the oxidation catalyst does not always become activated. Therefore, it is desirable to start the forced regeneration of the filter in a vehicle running state in which the engine load is relatively high (cylinder temperature is relatively high).

    However, even if forced regeneration of the filter is started in a state where the engine load is high, the vehicle frequently runs in a low engine load state or starts / stops before the oxidation catalyst is activated by the sub-injection. It may be in a running state that repeats. In this case, unburned fuel for increasing the filter temperature is supplied to the oxidation catalyst without activating the oxidation catalyst, and the unburned fuel and the sub-injected fuel are wasted, and naturally the filter is regenerated. I ca n’t plan. In addition, even if the oxidation catalyst is once activated, after that, the vehicle enters a traveling state with a low engine load, or a traveling state in which start and stop are frequently repeated, and the oxidation catalyst returns to a less active state. Regeneration may be insufficient. Even in this case, the unburned fuel and the sub-injected fuel previously supplied are wasted.

    Even if a temperature sensor is provided in the oxidation catalyst and the sub-injection is executed for a predetermined time, the forced regeneration of the filter may be stopped when the oxidation catalyst does not reach the activation temperature. All the sub-injected fuel is wasted.

    That is, an object of the present invention is to prevent fuel from being wasted and causing deterioration in fuel consumption with respect to forced regeneration of the filter as described above.

    The present invention addresses such a problem by using the road information obtained by the navigation system to determine whether or not the oxidation catalyst is activated when forced regeneration of the filter is started. Whether or not the state can be maintained is predicted, and when it is predicted that the vehicle cannot travel with the oxidation catalyst activated, the filter regeneration is not started.

That is, the invention according to claim 1 is a filter provided in an exhaust passage of a vehicle engine for collecting particulates in exhaust gas;
Fine particle amount detection means for detecting a parameter value related to the amount of fine particles collected by the filter;
An oxidation catalyst provided in the exhaust passage upstream of the filter;
When the particulate matter amount of the filter becomes a predetermined amount or more based on the detection value of the particulate matter amount detection means while the vehicle is running, main fuel is injected into the cylinder to obtain the output of the engine. In the expansion stroke after injection, sub-injection for injecting fuel into the cylinder is executed to increase the exhaust gas temperature to activate the oxidation catalyst, and the filter by the oxidation reaction heat of unburned fuel in the activated oxidation catalyst An exhaust emission control device for an engine, comprising a filter forced regeneration means for burning particulates collected by the filter by raising the temperature of the filter,
Means for detecting the present location of the host vehicle, storage means for map information, and means for inputting the travel destination of the host vehicle, and a travel route to the destination based on the map information by inputting the destination A navigation system that provides road information on the travel route
Based on the road information obtained from the navigation system, it is determined whether or not the own vehicle can travel with the oxidation catalyst activated, and the forced regeneration means is used when the traveling cannot be performed. And an activation determination means for prohibiting forced regeneration of the filter according to the above.

    Therefore, even if the amount of particulates collected by the filter exceeds a predetermined value, the road information from the navigation system indicates that the traveling route ahead of the vehicle is an urban road or the like and the vehicle activates the oxidation catalyst. When it is determined that traveling cannot be performed, the forced regeneration of the filter is not started. Therefore, sub-injection for activating the oxidation catalyst is not wasted, and deterioration of fuel consumption can be avoided.

The invention according to claim 2 is the invention according to claim 1,
The activation determining means activates the oxidation catalyst when there is an urban road predetermined in the map information within a predetermined range of a travel route ahead of the host vehicle based on the road information of the navigation system. It is characterized in that it is determined that it is not possible to carry out the travel that has been made.

    In other words, while traveling on urban roads, the vehicle speed is limited and there are many intersections and traffic lights, so the vehicle starts and stops frequently, and the engine load is relatively high. It is difficult to maintain a traveling state where the internal temperature is high. Therefore, in the present invention, when the host vehicle is traveling on an urban road, or when the host vehicle moves to the urban road when traveling within a predetermined distance range, the oxidation catalyst is activated even if sub-injection is executed. Since the activation level is not likely to be reached or the activation level is likely to be lowered even once activated, the forced regeneration of the filter is not started.

The invention according to claim 3 is a filter provided in an exhaust passage of an engine of a vehicle for collecting particulates in exhaust gas,
Fine particle amount detection means for detecting a parameter value related to the amount of fine particles collected by the filter;
An oxidation catalyst provided in the exhaust passage upstream of the filter;
When the particulate matter amount of the filter becomes a predetermined amount or more based on the detection value of the particulate matter amount detection means while the vehicle is running, main fuel is injected into the cylinder to obtain the output of the engine. In the expansion stroke after injection, sub-injection for injecting fuel into the cylinder is executed to increase the exhaust gas temperature and activate the oxidation catalyst, and the oxidation reaction heat of the unburned fuel in the activated oxidation catalyst An exhaust emission control device for an engine comprising a filter forced regeneration means for raising the temperature of the filter and burning the particulates collected in the filter,
Means for detecting the current location of the host vehicle, means for storing map information, means for inputting the travel destination of the host vehicle, and means for receiving road traffic information; A navigation system that sets a travel route to the destination based on the road and provides road traffic information related to the occurrence of traffic congestion on the travel route;
Based on road traffic information related to the occurrence of traffic congestion obtained by the navigation system, it is determined whether or not the host vehicle can travel with the oxidation catalyst activated, and the traveling can be performed. And an activation determining means for prohibiting the forced regeneration of the filter by the forced regeneration means when it is not possible.

    Therefore, even if the amount of particulates collected by the filter exceeds a predetermined value, the vehicle raises the exhaust gas temperature by sub-injection due to traffic congestion due to road traffic information related to the occurrence of traffic congestion from the navigation system. If it is determined that traveling with the oxidation catalyst activated cannot be performed, the forced regeneration of the filter is not started. Therefore, the auxiliary injection is not performed unnecessarily, and deterioration of fuel consumption can be avoided.

The invention according to claim 4 is the invention according to claim 3,
The activation determination means may cause the vehicle to travel with the oxidation catalyst activated when there is road traffic information related to the occurrence of traffic congestion within a predetermined range of the traveling route ahead of the vehicle. It is characterized by determining that it is not possible.

    That is, when the host vehicle is involved in a traffic jam, or when it is expected to get involved in a traffic jam if it travels within a predetermined distance, the oxidation catalyst will not be activated even if the sub-injection is executed, or once Even if activated, the activation level is likely to be low. In this case, however, according to the present invention, the forced regeneration of the filter is not started, and therefore, the sub-injection is not performed wastefully and the fuel consumption is deteriorated. Can be avoided.

The invention according to claim 5 is the invention according to claim 2 or claim 4,
The predetermined range is defined by a time required from the start of execution of the sub-injection until the oxidation catalyst is activated and a vehicle speed of the host vehicle.

    That is, when the current traveling state of the host vehicle is maintained while executing the sub-injection, the traveling distance until the oxidation catalyst is activated is obtained by multiplying the time by the vehicle speed. Therefore, according to the present invention, since the predetermined range is determined according to the traveling state of the host vehicle, it is accurately determined whether or not the host vehicle can travel with the oxidation catalyst activated by the sub-injection. This is advantageous in avoiding unnecessary sub-injection.

    As described above, according to the present invention, when the filter is forcibly regenerated, the exhaust gas of the engine in which the sub-injection of the fuel is executed to activate the oxidation catalyst disposed in the exhaust passage upstream of the filter. In the purifying apparatus, based on the road information on the travel route of the host vehicle obtained from the map information of the navigation system or on the road traffic information related to the traffic congestion on the travel route received by the navigation system, When it is determined that traveling with the oxidation catalyst activated cannot be performed, the forced regeneration of the filter is prohibited, so that sub-injection is not performed wastefully, resulting in deterioration of fuel consumption. Is prevented.

    Further, a predetermined range in front of the host vehicle for determining whether or not the host vehicle can run with the oxidation catalyst activated by sub-injection based on the presence of an urban road or the occurrence of traffic congestion, According to what is determined by the time required from the start of the sub-injection to the activation of the oxidation catalyst and the vehicle speed of the host vehicle, the determination can be made with high accuracy and wasted. This is advantageous in avoiding secondary injection.

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

<Engine configuration>
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 diesel particulate filter (DPF) 17 that collects particulates in the exhaust gas are disposed in order from the upstream side to the downstream side. ing. Exhaust pressure sensors 18 and 19 are disposed upstream and downstream of the filter 17. The filter 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 EGR valve (exhaust gas recirculation amount adjustment valve) 22 and a cooler 23 for cooling the exhaust gas with engine coolant are disposed.

    Fuel in the fuel tank (not shown) is supplied to the fuel injection valve 7 by a fuel supply pipe 28 via a fuel filter 25, a fuel injection pump 26, and a common rail 27 as a pressure accumulating means. 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.

    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, and 34 is a sensor that detects the exhaust gas temperature flowing into the filter 17. , 35 are sensors for detecting the exhaust gas temperature flowing out from the filter 17.

    Next, a control system for forced regeneration of the filter 17 will be described.

-Control system configuration-
An ECU (engine control unit) 40 using a microcomputer shown in FIG. 2 is used for forced regeneration in which the particulates are burned to regenerate the filter 17 when the amount of particulates collected by the filter 17 increases. In addition, a navigation system 41 is provided to appropriately perform the forced regeneration using map information and road traffic information.

    That is, the ECU 40 determines whether or not forced regeneration is possible based on road information from the navigation system 41 and forced regeneration means 42 that performs forced regeneration of the filter 17 by fuel injection control by the fuel injection valve 7 while the vehicle is traveling. An activation determination means 43 for the oxidation catalyst 16 is provided. In addition, exhaust pressure sensors 18 and 19, exhaust gas temperature sensor 44, crank angle sensor 45, and accelerator opening for detecting the accelerator opening of the engine (depressing amount of the accelerator pedal) for forced regeneration of the filter and determination of whether or not it is possible. A sensor 46 and a vehicle speed sensor 47 are provided.

    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 filter 17. That is, the amount of fine particles accumulated on the filter 17 is detected based on the differential pressure between the exhaust pressures detected by the sensors 18 and 19, and the larger the differential pressure, the larger the accumulated amount is determined. can do. The accelerator opening sensor 46 is used to determine the engine load. The accelerator opening sensor 46 and the crank angle sensor 45 detect the parameter values related to the engine operating state (engine load and engine speed). The operating state detecting means is configured.

    The forced regeneration means 42 determines that the amount of particulates collected by the filter 17 is greater than or equal to a predetermined amount α based on detection signals from the exhaust pressure sensors 18, 19, and the vehicle based on the output of the vehicle speed sensor 47. Is in an operating state in which the oxidation catalyst 16 is activated (a predetermined vehicle speed (for example, 50 km / h) or more), and when the execution is not prohibited by the activation determination means 43, the filter 17 is forced. Perform playback.

    That is, the forced regeneration means 42 executes the first sub-injection in which a small amount of fuel is injected in the expansion stroke after the main injection in which the fuel is injected near the top dead center of the compression stroke to generate the engine output. By performing a second sub-injection in which a small amount of fuel is injected at a timing (expansion stroke or exhaust stroke) retarded from the first sub-injection after a predetermined activation time has elapsed. 17 is reproduced. Then, the forced regeneration is terminated when the amount of the fine particles becomes equal to or less than the predetermined amount β. Note that α> β.

    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 first 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. This first sub-injected fuel is burned in the cylinder during the expansion stroke of the engine, thereby increasing the exhaust gas temperature and promoting the activation of the oxidation catalyst 16.

    The first sub-injection amount is basically set so 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 first sub-injection timing is in the range of 10 ° CA to 60 ° CA, preferably in the range of 20 ° CA to 50 ° CA, in order to combust the injected fuel in the cylinder. The engine load is set to be slower as the engine load becomes higher and the engine speed becomes higher.

    The second 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 second sub-injection, unburned fuel or partially oxidized unburned fuel is supplied to the oxidation catalyst 16, and the temperature of the exhaust gas flowing into the filter 17 is increased by the oxidation reaction heat of the fuel at the oxidation catalyst 16, and the filter The temperature of 17 is raised so that the fine particles burn.

    Similarly to the first sub-injection amount, the second sub-injection amount is basically set so 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. In the second sub-injection time, in order to discharge the injected fuel by being slightly thermally decomposed so as to be easily burned by the oxidation catalyst 16, the engine is within the range of 50 ° CA to 120 ° CA (after the top dead center of the compression stroke). It is set to become slower as the load becomes higher and as the engine speed becomes higher.

    The navigation system 41 calculates a current location and a traveling direction of the vehicle based on a GPS antenna 52 for receiving a transmission radio wave from a GPS (Global Positioning System) artificial satellite and a received signal from the GPS antenna 52. GPS receiver 53, a gyro compass 54 provided on the vehicle for detecting a change in the traveling direction of the host vehicle, a vehicle speed sensor 47 for detecting the traveling speed of the host vehicle, , An operation unit 56 for inputting various commands such as designation of a travel route from the current location to the destination, and a player 57 for reading the map information from a CD-ROM (or DVD) storing map information. A display 58 for displaying a road map and the current location, a GPS receiver 53, a gyro compass 54, a vehicle speed sensor 7. The information from the operation unit 56 and the CD-ROM player 57 is taken in, and the current location, traveling direction, destination, traveling route, etc. of the host vehicle are mainly displayed on the display 58, and the host vehicle travels to the driver. A navigation control unit 51 for providing guidance.

    In the map information stored in the CD-ROM, the road type (by expressway, suburban road, and urban road) is stored for each predetermined section of the road, the altitude of each point on the road, the position of the traffic light, etc. Is remembered.

    The GPS receiver 52 is used for so-called GPS navigation, and measures the current location and traveling direction of the host vehicle based on radio waves from a GPS artificial satellite. On the other hand, the gyrocompass 54 and the vehicle speed sensor 47 are used for so-called autonomous navigation, and detect the relative movement amount of the vehicle and update the current location and the traveling direction sequentially while updating the current location and the traveling direction. This is supplemented when the measurement result by the GPS receiver 53 is not normal, such as when the vehicle cannot receive radio waves from the artificial satellite.

    Further, in this embodiment, a traffic information receiver 60 that acquires the traffic information from a communication network that provides traffic information such as VICS by the beacon receiving antenna 59 is mounted, and receives road traffic information of the own vehicle travel route. This is demodulated and sent to the navigation control unit 51.

    The navigation control unit 51 of the navigation system 41 and the ECU 40 described above are connected so as to be able to communicate with each other, and in response to a request from the ECU 40, road information (map information and road information) mainly on a travel route to the destination of the host vehicle. Traffic information) is transmitted from the navigation control unit 51.

    In the navigation system 41, the GPS antenna 52, the GPS receiver 53, the gyro compass 54, and the vehicle speed sensor 47 constitute a means for detecting the current location of the host vehicle, and the CD-ROM and its player 57 constitute a map information storage means. The operation unit 56 constitutes input means.

    Based on the road information from the navigation system 41, the activation determination unit 43 determines whether or not the host vehicle can travel while increasing the exhaust gas temperature and activating the oxidation catalyst 16 by the first sub-injection. Determination is made, and forced regeneration of the filter 17 by the forced regeneration means 42 is prohibited when the traveling cannot be performed.

    Specifically, based on the map information of the navigation system 41, when the host vehicle is traveling on an urban road, it is determined that traveling that activates the oxidation catalyst 16 by the first sub-injection cannot be performed. The forced regeneration by the forced regeneration means 42 is prohibited. In addition, when the navigation system 41 gives road traffic information related to the occurrence of traffic congestion in a predetermined range of the travel route ahead of the host vehicle, the travel that activates the oxidation catalyst 16 by the first sub-injection is performed. It is determined that it cannot be performed, and forced regeneration by the forced regeneration means 42 is prohibited.

    The predetermined range is obtained by multiplying the activation time required from the start of the execution of the first sub-injection to the activation of the oxidation catalyst 16 by the current vehicle speed of the host vehicle. This is the travel distance of the host vehicle until it is activated. In this case, the activation time is the sub-injection execution time, which is the difference between the temperature at which the oxidation catalyst 16 exhibits activity (the temperature set in advance through experiments or the like) and the current temperature of the oxidation catalyst 16 determined by the exhaust gas temperature sensor 34. It is obtained by dividing by the temperature rise value per unit time of the oxidation catalyst 16 (a value set in advance by experiments or the like).

    The road traffic information related to the occurrence of traffic congestion includes information on traffic restrictions such as speed limit and lane reduction, and information on occurrence of traffic accidents in addition to information that traffic congestion has occurred.

    Note that when a detour is taken to avoid the traffic jam based on the map information of the navigation system 41, there is no information related to the occurrence of the traffic jam in the travel route ahead of the host vehicle. The prohibition is automatically lifted.

-Control flow-
The travel destination of the host vehicle is input in advance using the operation unit 56 of the navigation system 41, and the travel route is set. Specifically, when the travel destination is input, the control unit 51 moves from the current location to the destination based on the current location obtained from the GPS receiver 53 and the gyrocompass 54 and the map information stored in the CD-ROM player 57. Is calculated and displayed on the display 58 together with the map. When there are a plurality of travel routes, the occupant selects with the operation unit 56.

    As shown in FIG. 3, navigation information is detected in step S1 after the start. Specifically, the map information related to the vehicle speed (the road type of the travel route, the number of traffic lights, etc.) is read out from the CD-ROM of the navigation system 41, and the road traffic information (traffic of the travel route) is obtained by the traffic information receiver 60. Regulations, traffic congestion, accidents, etc.).

    In the next step S2, the exhaust pressure differential pressure P before and after the filter 17 is read by the detection signals of the exhaust pressure sensors 18, 19, and the particulate trapping amount M of the filter 17 is calculated in step S3 based on this differential pressure P. In the subsequent step S4, it is determined whether or not the amount M of particulate traps is equal to or less than a predetermined amount β that is a threshold value for forced filter regeneration. When the particulate trapping amount M is equal to or smaller than the predetermined amount β, the filter 17 is not forcibly regenerated and returns.

    When the particle trapping amount M is larger than the predetermined amount β in step S4, the process proceeds to step S5, and it is determined whether or not the particle trapping amount M is greater than or equal to a predetermined amount α that is a filter start regeneration threshold. When the particulate trapping amount M is equal to or larger than the predetermined amount α, the process proceeds to step S6, and it is determined whether or not information related to the occurrence of traffic congestion within a predetermined range of the traveling route ahead of the host vehicle is output from the navigation system 41. . When such information is output, the forced regeneration of the filter 17 is prohibited and the process returns.

    If there is no information related to the occurrence of traffic congestion within a predetermined range of the travel route ahead of the host vehicle, the process proceeds to step S7 to determine whether the host vehicle is currently traveling on an urban road. When traveling on an urban road, forced regeneration of the filter 17 is prohibited and the process returns. Thus, when the host vehicle is not traveling on a city road, the process proceeds to step S8 where the forced regeneration of the filter 17 by the forced regeneration means 41 is executed.

    If it is determined in step S5 that the trapped amount M is smaller than the predetermined amount α, the process proceeds to step S9, where it is determined whether the forced regeneration of the filter 17 is currently being continued. For example, the process proceeds to step S8, in which the forcing is continued until the particle trapping amount M becomes equal to or less than the predetermined amount in step S4.

    As described above, even when the amount of fine particles in the filter 17 is equal to or greater than the predetermined amount α which is the threshold value for forced regeneration, information related to the occurrence of traffic congestion within the predetermined range of the traveling route ahead of the host vehicle is output. When the vehicle is traveling on an urban road even when such information is not available, the forced regeneration of the filter 17 is prohibited.

    Therefore, after the forced regeneration of the filter 17 is started, that is, the execution of the first sub-injection is started, before the oxidation catalyst 16 is activated, the host vehicle is involved in a traffic jam and activated. The first sub-injection is not wasted and the second sub-injection is not performed unnecessarily. In addition, when the host vehicle is traveling on an urban road where it is difficult to activate the oxidation catalyst by the first sub-injection, the first sub-injection is performed wastefully, and further, the second sub-injection is wasteful. It will not be executed. Therefore, deterioration of the fuel consumption of the vehicle can be avoided.

    The time required to activate the oxidation catalyst 16 may be changed based on the map information of the navigation system 41. For example, if the traveling route ahead of the host vehicle is an uphill road, the engine load increases and the exhaust gas temperature increases accordingly, so that the oxidation catalyst 16 can be activated early. Therefore, in this case, the temperature increase value per unit time of the oxidation catalyst 16 may be changed to a high value so that the activation time is shortened, and thus the predetermined range is narrowed.

    Further, in the above embodiment, forced regeneration during urban road traveling is prohibited based on the road type classified on the map information. In order to prevent forced regeneration, roads are classified on the map information based on the number of intersections or traffic lights per unit distance. When there are more than a predetermined number of intersections or traffic lights per unit distance, forced regeneration of filter 17 You may make it prohibit.

    Alternatively, the number of intersections or traffic lights per unit distance of the travel route ahead of the host vehicle is obtained without classifying the road as described above, and the forced regeneration of the filter 17 is prohibited when the number is equal to or greater than a predetermined value. You may do it.

    In the above embodiment, the forced regeneration of the filter 17 is prohibited when the host vehicle is traveling on an urban road. However, the host vehicle has a large number of intersections or traffic lights per unit road at present. Even when the vehicle is not traveling in the section, the forced regeneration of the filter 17 is prohibited even when traveling in such a city road, the number of intersections or the number of traffic lights due to traveling within the predetermined range. Also good.

    In the above embodiment, the forced regeneration of the filter 17 is prohibited when the oxidation catalyst 16 cannot be activated by the first sub-injection. However, even if the oxidation catalyst 16 is activated once, the activation thereof is activated. Also, when traveling that maintains the state for a predetermined period (for example, until the amount of fine particles in the filter 17 is reduced by half) cannot be performed, or when traveling that maintains the activated state until forced regeneration of the filter 17 is completed cannot be performed. Alternatively, it may be determined that the host vehicle cannot travel with the oxidation catalyst 16 activated, and the forced regeneration of the filter 17 may be prohibited.

    The second sub-injection may be started at the same time as the first sub-injection is started. Further, the first sub-injection is continuously executed during the forced regeneration period of the filter 17. Also good.

    Further, when the filter is regenerated, an intake throttle that reduces the amount of intake air flowing into the cylinder by the intake throttle valve or an exhaust throttle that reduces the exhaust flow rate by providing a throttle valve in the exhaust passage downstream of the filter 17 is performed. Thus, the temperature of the filter 17 may be quickly increased.

    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 concerning an embodiment. It is a control flow figure concerning the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Intake passage 3 Exhaust passage 5 Cylinder combustion chamber 7 Fuel injection valve 16 Oxidation catalyst 17 Filter 18, 19 Exhaust pressure sensor 40 ECU
41 navigation system 42 forced regeneration means 43 activation determination means 52 to 54 current vehicle location detection means 56 input means 57 map information storage means 59, 60 road traffic information reception means

Claims (5)

A filter provided in an exhaust passage of a vehicle engine for collecting particulates in exhaust gas;
Fine particle amount detection means for detecting a parameter value related to the amount of fine particles collected by the filter;
An oxidation catalyst provided in the exhaust passage upstream of the filter;
When the particulate matter amount of the filter becomes a predetermined amount or more based on the detection value of the particulate matter amount detection means while the vehicle is running, main fuel is injected into the cylinder to obtain the output of the engine. In the expansion stroke after injection, sub-injection for injecting fuel into the cylinder is executed to increase the exhaust gas temperature to activate the oxidation catalyst, and the filter by the oxidation reaction heat of unburned fuel in the activated oxidation catalyst An exhaust emission control device for an engine, comprising a filter forced regeneration means for burning particulates collected by the filter by raising the temperature of the filter,
Means for detecting the present location of the host vehicle, storage means for map information, and means for inputting the travel destination of the host vehicle, and a travel route to the destination based on the map information by inputting the destination A navigation system that provides road information on the travel route
Based on the road information obtained from the navigation system, it is determined whether or not the own vehicle can travel with the oxidation catalyst activated, and the forced regeneration means is used when the traveling cannot be performed. And an activation determining means for prohibiting the forced regeneration of the filter by the engine exhaust purification device. In claim 1,
The activation determining means activates the oxidation catalyst when there is an urban road predetermined in the map information within a predetermined range of a travel route ahead of the host vehicle based on the road information of the navigation system. An exhaust emission control device for an engine, characterized in that it is determined that it is not possible to perform the travel that has been made into an engine. A filter provided in an exhaust passage of a vehicle engine for collecting particulates in exhaust gas;
Fine particle amount detection means for detecting a parameter value related to the amount of fine particles collected by the filter;
An oxidation catalyst provided in the exhaust passage upstream of the filter;
When the particulate matter amount of the filter becomes a predetermined amount or more based on the detection value of the particulate matter amount detection means while the vehicle is running, main fuel is injected into the cylinder to obtain the output of the engine. In the expansion stroke after injection, sub-injection for injecting fuel into the cylinder is executed to increase the exhaust gas temperature and activate the oxidation catalyst, and the oxidation reaction heat of the unburned fuel in the activated oxidation catalyst An exhaust emission control device for an engine comprising a filter forced regeneration means for raising the temperature of the filter and burning the particulates collected in the filter,
Means for detecting the current location of the host vehicle, means for storing map information, means for inputting the travel destination of the host vehicle, and means for receiving road traffic information; A navigation system that sets a travel route to the destination based on the road and provides road traffic information related to the occurrence of traffic congestion on the travel route;
Based on road traffic information related to the occurrence of traffic congestion obtained by the navigation system, it is determined whether or not the host vehicle can travel with the oxidation catalyst activated, and the traveling can be performed. An exhaust emission control device for an engine, comprising: an activation determination unit that prohibits the forced regeneration of the filter by the forced regeneration unit when it cannot be performed. In claim 3,
The activation determination means may cause the vehicle to travel with the oxidation catalyst activated when there is road traffic information related to the occurrence of traffic congestion within a predetermined range of the traveling route ahead of the vehicle. An exhaust emission control device for an engine, characterized in that it is determined that the engine cannot be used. In claim 2 or claim 4,
The engine exhaust gas purification apparatus, wherein the predetermined range is determined by a time required from the start of execution of the sub-injection until the oxidation catalyst is activated and a vehicle speed of the host vehicle.

Images