JP4457696B2 - 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 particulates when the amount of particulates collected by the filter exceeds a predetermined amount. Regarding this regeneration, there is known a forced regeneration means for raising the temperature of the filter and burning the particulates deposited on the filter while the vehicle is running when the amount of collected particulates exceeds a predetermined amount. (See Patent Document 1). That is, Patent Document 1 describes that an electric heater is installed in the filter, the electric heater is operated to ignite the fine particles of the filter, and secondary air is supplied to the filter to burn the fine particles. ing.

Regarding the regeneration of the filter, the fuel is injected into the cylinder in the expansion stroke after the main injection in which the fuel is injected into the cylinder near the top dead center of the compression stroke of the engine. It is also known that fuel is supplied to a catalyst, and the temperature of the filter is raised by combustion reaction heat of the fuel in the oxidation catalyst to burn particulates.
JP-A-8-210122

    In the forced regeneration technology of the filter, the regeneration timing is determined by detecting the particulate collection amount of the filter as needed, but even if the particulate collection amount of the filter is still small and it is determined that regeneration is unnecessary. When the vehicle is involved in a traffic jam, the amount of particulate emission from the engine increases, so the filter may need to be regenerated.

    However, in the case of a method of heating and regenerating the filter with an electric heater, the amount of power generated by the engine is smaller than the electric load in a state of being involved in a traffic jam, so the electric power of the electric heater is covered by the discharge from the in-vehicle battery. As a result, the battery is likely to run out, and as a result, the filter is likely to be clogged thereafter due to regeneration failure. Also, even when the filter is heated and regenerated using an oxidation catalyst, the exhaust gas temperature is low and the oxidation catalyst does not become active when it is involved in traffic jams. Even if fuel is supplied, the filter cannot be heated and regenerated, and the filter is easily clogged.

    Accordingly, an object of the present invention is to prevent the battery from running out and clogging of the filter even when the vehicle is involved in a traffic jam.

    In response to such a problem, the present invention performs forced regeneration of the filter early when the vehicle is expected to be involved in a traffic jam, and enters the traffic jam section with a reduced amount of filter fine particles. I was able to enter.

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;
While the vehicle is running, the filter is configured so that the particulates collected by the filter are combusted when the particulate amount of the filter exceeds a predetermined amount based on the detection value of the particulate amount detection means. An exhaust emission control device for an engine comprising a forced regeneration means for forcibly regenerating the filter by raising the temperature of the filter,
Means for detecting the current location of the host vehicle, map information storage means, means for inputting the travel destination of the host vehicle, and means for receiving road traffic information are provided. Based on the map information by inputting the travel destination. A navigation system for setting road routes to the destination and providing road traffic information;
Threshold value changing means for reducing the predetermined amount for starting execution of the forced regeneration means when the navigation system obtains road traffic information related to the occurrence of traffic congestion on the travel route. It is characterized by.

    Therefore, when the road traffic information related to the occurrence of traffic congestion is obtained, the forced regeneration of the filter is started from a state where the amount of particulate matter of the filter is relatively small, and the state where the amount of particulate matter of the filter is reduced You can move to a traffic jam section. Therefore, even if the amount of fine particles discharged from the engine increases during traveling in a traffic jam section, it is avoided that forced regeneration must be performed, and when the filter is regenerated using an electric heater, The problem of regeneration failure when the filter is regenerated using the oxidation catalyst is not caused, and the filter is prevented from being clogged.

The invention according to claim 2 is the invention according to claim 1,
The threshold value changing means reduces the predetermined amount only when the host vehicle is traveling on an expressway.

    That is, when traveling on a general road other than an expressway, even if there is a traffic jam ahead, it can often be bypassed while avoiding the traffic jam, but it is generally difficult to bypass when traveling on an expressway. Therefore, in the present invention, the predetermined amount for starting execution of the forced regeneration means is reduced only when traveling on a highway. Accordingly, it is possible to avoid the above-mentioned battery exhaustion, filter regeneration failure, and clogging, and it is possible to avoid the deterioration of fuel consumption due to the forced regeneration being executed despite the circumvention of traffic congestion.

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;
While the vehicle is running, the filter is configured so that the particulates collected by the filter are combusted when the particulate amount of the filter exceeds a predetermined amount based on the detection value of the particulate amount detection means. An exhaust emission control device for an engine comprising a forced regeneration means for forcibly regenerating the filter by raising the temperature of the filter,
Means for detecting the current location of the host vehicle, map information storage means, means for inputting the travel destination of the host vehicle, and means for receiving road traffic information are provided. Based on the map information by inputting the travel destination. A navigation system that sets a travel route to the destination and provides road traffic information;
Regeneration that activates the forced regeneration means regardless of whether or not the amount of fine particles in the filter is greater than or equal to a predetermined amount when road traffic information related to the occurrence of traffic congestion on the travel route is obtained by the navigation system Control change means ,
The regeneration control changing means operates the forced regeneration means so that the amount of fine particles in the filter is equal to or less than a second predetermined amount that is smaller than the predetermined amount at the occurrence point of the traffic jam .

Therefore, when road traffic information related to the occurrence of traffic congestion is obtained, the amount of fine particles in the filter becomes equal to or less than a second predetermined amount that is smaller than the predetermined amount due to the operation of the forced regeneration means. Even if the amount of fine particles discharged from the engine increases during driving, forced regeneration cannot be avoided, and when using an electric heater to regenerate the filter, the battery runs out or an oxidation catalyst is used. Thus, there is no problem of regeneration failure when the filter is regenerated, and clogging of the filter is prevented.

The invention according to claim 4 is the invention according to claim 3 ,
The regeneration control changing means comprises data defining the particulate emission amount of the engine per unit mileage and the particulate combustion amount of the filter per unit mileage when the forced regeneration means is operated, and from the current location of the own vehicle The distance to the traffic congestion point is determined based on the map information of the navigation system, and the current particle amount of the filter is set so that the particle amount of the filter is equal to or less than the second predetermined amount at the traffic congestion occurrence point. And the operation timing of the forced regeneration means is set based on the data on the particulate discharge amount and particulate combustion amount and the distance.

Therefore, the forced regeneration means can be operated without waste so that the amount of fine particles in the filter is less than or equal to the second predetermined amount at the point of occurrence of traffic congestion, which is advantageous in carrying out the invention according to claim 3. Become.

The invention according to claim 5 is the invention according to claim 4 ,
The regeneration control changing means determines the particulate emission amount and particulate combustion amount for each road type, and determines the operation timing of the forced regeneration means according to the road type of the travel route obtained from the map information. The fine particle discharge amount and the fine particle combustion amount for setting are selected.

That is, in general, the amount of particulate emission and the amount of particulate combustion differ depending on the road type (for example, highway, urban road, suburban road, or road speed limit). On the other hand, the present invention sets the particulate emission amount and particulate combustion amount according to the type of road on the travel route obtained from the map information, so that the particulate amount of the filter at the traffic congestion occurrence point. The forced regeneration means can be operated without waste so as to be equal to or less than the second predetermined amount, which is advantageous in carrying out the invention according to claim 3 .

    The amount of engine particulate emission in accordance with the road type may be determined, for example, according to the size relationship of “highway <suburban road <urban road”. The particulate combustion amount of the filter according to the road type may be determined by, for example, the size relationship of “highway> suburban road> urban road”.

The invention according to claim 6 is any one of claims 3 to 5 ,
The regeneration control changing means operates the forced regeneration means so that the particulate amount of the filter is equal to or less than a second predetermined amount smaller than the predetermined amount only when the host vehicle is traveling on an expressway. And

    That is, when traveling on a general road other than an expressway, even if there is a traffic jam ahead, it can often be bypassed while avoiding the traffic jam, but it is generally difficult to bypass when traveling on an expressway. Therefore, in the present invention, the forced regeneration means is operated only when traveling on an expressway so that the amount of fine particles in the filter is equal to or smaller than a second predetermined amount that is smaller than the predetermined amount. Accordingly, it is possible to avoid the above-mentioned battery exhaustion, filter regeneration failure, and clogging, and it is possible to avoid the deterioration of fuel consumption due to the forced regeneration being executed despite the circumvention of traffic congestion.

The invention according to claim 7 is the invention according to claim 2 or claim 6 ,
Exhaust gas recirculation amount adjusting means for adjusting the recirculation amount of exhaust gas recirculated to the intake system of the engine;
Exhaust gas recirculation control means for prohibiting recirculation of the exhaust gas while the vehicle is traveling in the traffic congestion occurrence section based on the map information and road traffic information of the navigation system, To do.

    That is, when the exhaust gas is recirculated to the intake system, the combustibility of the engine is reduced and the amount of particulates discharged is increased. On the other hand, according to the present invention, the exhaust gas recirculation is prohibited while the host vehicle is traveling in the traffic congestion section, and accordingly, the accumulation of fine particles in the filter can be suppressed. This is advantageous in avoiding forced regeneration in the section.

The invention according to claim 8 is any one of claims 1 to 7 ,
The forced regeneration means is disposed upstream of the filter by injecting the fuel into the cylinder in an expansion stroke after the main injection in which the fuel is injected into the cylinder by an electric heater or near the top dead center of the compression stroke of the engine. The fuel is supplied to the oxidized catalyst, and the temperature of the filter is raised by the combustion reaction heat of the fuel in the oxidation catalyst.

    This eliminates the problem of battery exhaustion when the filter is regenerated using an electric heater and failure of regeneration when the filter is regenerated using an oxidation catalyst.

    As described above, according to the present invention, in the exhaust emission control device for an engine that operates the forced regeneration means when the amount of fine particles in the filter reaches a predetermined amount or more, the navigation system provides a travel route to the destination. When road traffic information related to the occurrence of traffic congestion is obtained, threshold change means for reducing the predetermined amount for starting execution of forced regeneration means is provided, so forced regeneration must be performed in a traffic congestion section. The problem of battery exhaustion when the filter is regenerated using an electric heater, failure of regeneration when the filter is regenerated using an oxidation catalyst, and clogging of the filter are solved.

Further, according to the present invention, in the exhaust emission control device for an engine that operates the forced regeneration means when the amount of particulates in the filter becomes a predetermined amount or more, the traffic congestion on the travel route to the destination is detected by the navigation system. when the road traffic information relating to generation is obtained, setting the reproduction control changing unit quantity of particulate filters actuate the forced regeneration means regardless of whether or not a predetermined amount or more digits, the occurrence of transportation congestion since the amount of particulates of the filter at the point was set to less than the second predetermined amount smaller than the predetermined amount, the force be forced to perform the reproduction is avoided in traffic congested section, of the filter with an electric heater Problems such as battery exhaustion when regenerating, regeneration failure when regenerating the filter using an oxidation catalyst, and clogging of the filter are solved.

    In addition, according to the above-described threshold change means or regeneration control change means that is activated only when the host vehicle is traveling on an expressway, in the situation where it is inevitable that the vehicle will be involved in traffic congestion, The problem of regeneration failure and clogging can be avoided, and it is possible to avoid the deterioration of fuel consumption due to the forced regeneration being executed, although the traffic congestion can be bypassed.

    In addition, data defining the particulate emission amount of the engine per unit travel distance and the particulate combustion amount of the filter per unit travel distance when the forced regeneration means is activated, and the current location of the vehicle obtained from the navigation system to the traffic congestion point The operation time of the forced regeneration means is set so that the particulate quantity of the filter is equal to or less than the second predetermined amount based on the distance to the filter and the current particulate quantity of the filter. This is advantageous in avoiding the above-mentioned problems such as battery exhaustion, filter regeneration failure, and clogging without causing deterioration of fuel consumption. According to what is determined for each type, it is further advantageous in avoiding the above-mentioned problem without causing deterioration of fuel consumption.

    In addition, according to what prohibits the exhaust gas recirculation while the host vehicle is traveling in a traffic jam section, it is further advantageous in avoiding forced regeneration in the traffic jam section.

    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, and a fuel return pipe 29 supplies the fuel tank. 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.

<Embodiment 1>
-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 includes a forced regeneration means 42 that performs forced regeneration of the filter 17 by fuel injection control by the fuel injection valve 7 during traveling of the vehicle, and a threshold value for starting the forced regeneration based on road information from the navigation system 41. And an EGR control means (exhaust gas recirculation control means) 44 for reducing the exhaust gas recirculation amount to zero during traveling in the traffic congestion section of the EGR valve 22 based on road information from the navigation system 41. Is provided. Further, exhaust pressure sensors 18 and 19, a crank angle sensor 45, an accelerator opening sensor 46 for detecting the accelerator opening (depressing amount of the accelerator pedal), and a vehicle speed sensor 47 are provided for forced regeneration of the filter. Yes.

    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 is based on the output of the vehicle speed sensor 47. When it is determined that the oxidation catalyst 16 is in an operation state in which the oxidation catalyst 16 is activated (a predetermined vehicle speed (for example, 50 km / h) or more), the filter 17 is forcibly regenerated. That is, the filter 17 is regenerated by executing the sub-injection in which the 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. 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 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 exhaust gas temperature flowing into the filter 17 is increased by the catalytic reaction heat in the oxidation catalyst 16, and the temperature of the filter 17 is combusted by fine particles. Raise as you do.

    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.

    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.

    The threshold value changing means 43 includes means for determining whether or not the host vehicle is traveling on the expressway based on the map information of the navigation system 41, and travels from the navigation system 41 to the destination while traveling on the expressway. When road traffic information related to the occurrence of traffic congestion on the route is obtained, the threshold value for starting execution of the forced regeneration means 42 is changed. Specifically, the predetermined amount α is reduced to the predetermined amount γ. The magnitude relationship between the predetermined amounts α, β, and γ is β <γ <α. Further, road traffic information related to the occurrence of traffic congestion includes information on traffic restriction sections such as speed limit and slanting reduction, and information on occurrence of traffic accidents, in addition to information that traffic congestion has occurred.

    However, a determination means for determining whether or not there is a detour to avoid traffic congestion on the travel route based on the map information of the navigation system 41 is provided. Even when the vehicle is traveling on an urban road or a suburban road, the threshold value may be changed when there is no detour based on the determination result of the determination means.

    The EGR control means 44 sets a target EGR rate with reference to an EGR rate map stored in advance electronically based on the accelerator opening and the engine speed, and operates the EGR valve 22 so as to reach the target EGR rate. Let The target EGR rate is set so as to increase as the accelerator opening decreases, and to increase as the engine speed decreases. However, in a direct injection type diesel engine, NOx generation can be suppressed as the EGR rate is increased and the air-fuel ratio of the combustion chamber is made richer. On the other hand, if the air-fuel ratio is too small, the amount of smoke generated, that is, There is a characteristic that the discharge amount of fine particles increases rapidly. Therefore, the target EGR rate is set to be as small as possible within a range where the air-fuel ratio of the combustion chamber does not increase rapidly.

    Thus, the EGR control means 44 of the present embodiment, based on the map information and the road traffic information of the navigation system 41, sets the target EGR to suppress the discharge of the fine particles as much as possible when the own vehicle enters the traffic congestion section. The rate is set to zero.

-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 A1 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 subsequent step A2, the differential pressure P between the exhaust pressures before and after the filter 17 is read by the detection signals of the exhaust pressure sensors 18 and 19, and the particulate accumulation amount M of the filter 17 is calculated based on the differential pressure P in step A3.

    In subsequent step A4, it is determined whether or not there is information related to traffic congestion based on the road traffic information. If there is no such information, the process proceeds to step A5, where the particulate accumulation amount M of the filter 17 is a predetermined amount β. It is determined whether it is equal to or less than (forced regeneration end threshold). If the particulate deposition amount M is equal to or less than the predetermined amount β, the process returns. If the particulate deposition amount M is larger than the predetermined amount β, the process proceeds to Step A6 to determine whether the particulate deposition amount M is equal to or greater than the predetermined amount α (forced regeneration start threshold). judge.

    When the fine particle accumulation amount M is equal to or larger than the predetermined amount α, the process proceeds to step A7 and the forced regeneration of the filter 17 by the forced regeneration means 42 is executed. When the amount M of accumulated particulates is not equal to or greater than the predetermined amount α, the process proceeds to step A8, where it is determined whether or not forced regeneration is continuing. If it is continued, the process proceeds to step A7 and forced regeneration is continued. If not, return. That is, the forced regeneration of the filter 17 is started when the particulate accumulation amount M is equal to or greater than the predetermined amount α. However, the forced regeneration is started if the particulate accumulation amount M is not less than the predetermined amount β that is the end threshold even when the amount is less than the predetermined amount α. Does not end.

    Next, when it is determined in step A4 that there is traffic congestion related information, the process proceeds to step A9, where it is determined whether or not there is information related to traffic congestion mitigation, and if the mitigation information is output, the process proceeds to step A5. . On the other hand, when it is determined that there is no such mitigation information, the process proceeds to step A10, and it is determined whether or not the host vehicle is currently traveling on a highway based on the map information. When not traveling on the highway, the process proceeds to step A5, and when traveling on the highway, the process proceeds to step A11.

    Step A5 and subsequent steps are normal control in which the start threshold value for forced regeneration of the filter 17 is set to a predetermined amount α and the end threshold value is set to a predetermined amount β. Steps A11 and subsequent steps are set to a predetermined amount γ and set an end threshold value. This is traffic control for a fixed amount β. In other words, when the vehicle is not driving on a highway (during driving on a city road or suburban road), it is generally possible to take a detour even if there is a traffic jam ahead of the vehicle. Therefore, normal control is performed, and the control shifts to traffic jam control only during traveling on a highway where such detouring is difficult.

    In the traffic jam control, in step A11, it is determined whether or not the particulate accumulation amount M of the filter 17 is equal to or less than a predetermined amount β (forced regeneration end threshold). If the particulate deposition amount M is equal to or less than the predetermined amount β, the process returns. If the particulate deposition amount M is greater than the predetermined amount β, the process proceeds to Step A12 to determine whether the particulate deposition amount M is equal to or greater than the predetermined amount γ (forced regeneration start threshold). judge. That is, the starting threshold value for forced regeneration of the filter 17 is changed from the predetermined amount α in the case of normal control to a predetermined amount γ that is smaller than this, and it is determined whether or not forced regeneration should be started.

    If the particulate accumulation amount M is greater than or equal to the predetermined amount γ, the process proceeds to step A7 where forced regeneration of the filter 17 by the forced regeneration means 42 is executed. When the amount M of particulate deposits is smaller than the predetermined amount γ, the process proceeds to step A13, where it is determined whether or not the forced regeneration is continuing. If it is continued, the process proceeds to step A7 and the forced regeneration is continued and continued. Otherwise return. When the host vehicle enters the traffic jam section, the EGR control means 44 sets the target EGR rate to zero and closes the EGR valve 22.

    FIG. 4 is a time chart showing the transition of the particulate accumulation amount threshold value for starting execution of forced regeneration of the filter 17 in the present embodiment, and until the traffic congestion related information is detected by the navigation system 41, the start threshold value is When the predetermined amount α is set and traffic congestion related information is detected, the start threshold is lowered to the predetermined amount γ when the host vehicle is traveling on the expressway. Thereafter, when the host vehicle enters a traffic jam section, EGR cut (EGR valve closed) is performed, and the amount of particulates discharged from the engine is reduced.

    As described above, when the traffic congestion related information is obtained on the travel route ahead of the host vehicle while the host vehicle is traveling on the expressway, the forced regeneration start threshold of the filter 17 is changed from the predetermined amount α to the predetermined amount γ. Therefore, the forced regeneration is executed early from the time when the amount M of accumulated particulate matter on the filter 17 is small. Therefore, by executing this forced regeneration, it is possible to enter the traffic congestion section with a small amount M of particulate deposits on the filter 17, and it is possible to avoid clogging of the filter 17 while traveling in this traffic congestion section.

    That is, during traveling in a traffic jam section, the vehicle speed decreases, and the vehicle starts and stops frequently, so that the amount of engine particulate emission tends to increase. In addition, since the exhaust gas temperature is lowered, the oxidation catalyst 16 becomes inactive, and even when fuel is injected in the expansion stroke, fuel cannot be burned in the oxidation catalyst 16 and the filter 17 can be regenerated. Can not. On the other hand, in the case of the above embodiment, the execution of the forced regeneration before entering the above-described traffic jam section allows the user to enter the traffic jam section with a reduced amount of particulates deposited on the filter 17. In addition, since the EGR cut is performed in this traffic jam section, an increase in engine particulate emission can be suppressed. Therefore, in the traffic jam section, it is possible to avoid the amount of accumulated particulate matter on the filter 17 from becoming higher than the forced regeneration start threshold, and to prevent clogging due to the fact that the forced regeneration of the filter 17 cannot be performed.

    The forced regeneration start threshold value of the filter 17 when the host vehicle enters the traffic jam section may remain the predetermined amount γ, but is preferably returned to the predetermined amount α.

    That is, in the above embodiment, forced regeneration (fuel expansion stroke injection) is not executed unless the vehicle enters an operation state in which the oxidation catalyst 16 is activated. Therefore, when the start threshold value is kept at the predetermined amount γ, even if the particulate deposition amount M of the filter 17 may be equal to or larger than the predetermined amount γ, the vehicle speed is low and the operation state in which the oxidation catalyst 16 is activated. It is avoided that the expansion stroke injection is performed in vain in the traffic congestion section that does not become.

    However, if the start threshold value is returned to the predetermined amount α, the particulate deposition amount M of the filter 17 is less likely to be greater than or equal to the predetermined amount α during travel in the traffic congestion section, and therefore, the expansion stroke injection in the traffic congestion section. Is further advantageous in avoiding unnecessary execution.

    Note that the end threshold for forced regeneration when there is traffic jam related information is set to a predetermined amount β as in the normal control in the above embodiment, but is changed to a value smaller than the predetermined amount β, and the filter 17 is used for the traffic jam. It may be easier to avoid clogging during traveling in the section.

    Further, the degree of traffic jam (traffic distance) may be obtained from the traffic jam related information, and the end threshold value of the forced regeneration may be changed according to the degree (that is, the end threshold value is lowered as the degree of traffic jam is significant). .

<Embodiment 2>
In the present embodiment, when the above-described traffic jam related information is obtained, the particulate accumulation amount of the filter 17 is set to be equal to or smaller than a second predetermined amount at the traffic jam occurrence point.

-Control system configuration-
FIG. 5 shows the configuration of the control system. The difference from the first embodiment is that the ECU 40 includes a regeneration control change means 63 that changes the control of the forced regeneration means 42 instead of the threshold value change means. .

    The regeneration control changing unit 63 determines whether or not the particulate accumulation amount M of the filter 17 is equal to or greater than the predetermined amount α that is the forcible start threshold when the traffic congestion related information on the travel route is obtained by the navigation system 41. Regardless, when the host vehicle reaches the traffic congestion point, the forced regeneration means 42 is operated so that the amount M of particulate accumulation becomes a second predetermined amount smaller than the predetermined amount α.

    Specifically, the regeneration control changing means 63 determines the particulate quantity that determines the particulate emission amount b of the engine per unit travel distance and the particulate combustion quantity c of the filter 17 per unit travel distance when the forced regeneration means 42 is operated. Data and time setting means for setting a forced regeneration time by the forced regeneration means 42 are provided.

    Regarding the particulate emission amount b and particulate combustion amount c in the particulate amount data, b = Xb (g / km) when driving on an expressway, c = Xc (g / km) when traveling on a highway, and when traveling on a suburban road. b = Yb (g / km), c = Yc (g / km), and b = Zb (g / km) and c = Zc (g / km) when traveling on an urban road.

    However, the magnitude relationship of the particulate discharge amount b is Xb <Yb <Zb. This is based on the fact that the amount of particulate emission from the engine increases as the number of times of acceleration / deceleration of the host vehicle increases as in an urban area. The magnitude relationship of the particulate combustion amount c is Xc> Yc> Zc. This is based on the fact that the fine particles of the filter 17 are easily burned as the time for which the vehicle continuously travels becomes longer.

The forced regeneration time setting means calculates the distance D (km) from the current location of the vehicle to the traffic congestion point from the map information of the navigation system 41, and when this distance D and traffic congestion related information are obtained. Based on the fine particle accumulation amount a of the filter 17, the fine particle discharge amount b and the fine particle combustion amount c, and the second predetermined amount, the travel distance L to be forcibly regenerated is obtained by the following equation, and from the traffic congestion point: The time when the vehicle reaches a point before the travel distance L is set as the regeneration start time, and the time when the host vehicle reaches the traffic jam point is set as the regeneration end time. In other words, the point before the travel distance L from the traffic congestion point becomes the regeneration start point, and the point that has traveled the distance L from there becomes the regeneration end point.
L = (a + b × D−second predetermined amount) ÷ c

    The particulate emission amount b and the particulate combustion amount c are (Xb, Xc), (Yb, Yc) and (Zb, Zc) according to the type of road on the travel route obtained from the map information of the navigation system 41. Selected from combinations.

-Control flow-
FIG. 6 shows a control flow of this embodiment. As in the case of the first embodiment, 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. Further, steps B1 to B9 after the start correspond to steps A1 to A9 in FIG. 3 and are the same as those in the first embodiment.

    When there is no traffic congestion mitigation information in step B9, the process proceeds to step B10, and the distance D from the point (current location) where the traffic congestion related information on the travel route is detected to the traffic congestion point is calculated from the map information. In the subsequent step B11, a forced regeneration time is set so that the particulate accumulation amount M of the filter 17 becomes the second predetermined amount when the traffic congestion point is reached. That is, the travel distance L to be forcibly regenerated based on the particulate accumulation amount a of the filter 17 at present, the particulate emission amount b and particulate combustion amount c corresponding to the road type obtained from the map information, and the distance D. The reproduction start point before the travel distance L from the traffic congestion point is obtained.

    In a subsequent step B12, it is determined whether or not the vehicle has arrived at the regeneration start point or has passed the regeneration start point. If the answer is no, the process returns. On the other hand, when the own vehicle arrives at or passes through the regeneration start point, the process proceeds to Step B13. In step B13, it is determined whether or not the host vehicle has reached a traffic congestion occurrence point. If not, the process proceeds to step B7 to perform forced regeneration of the filter 17 by the forced regeneration means 42. When the value reaches, the forced regeneration is terminated and the process returns, while EGR cut (EGR valve closed) is executed in the traffic jam section.

    FIG. 7 is a time chart showing the transition of the particulate accumulation amount of the filter 17 and the forced regeneration time when the traffic congestion information is detected.

    That is, when the forced regeneration control is not changed based on the traffic jam related information, the amount of accumulated particulate matter of the filter 17 is a + b × D (a; The amount of particulates deposited on the filter 17 is b; the amount of particulates discharged per unit travel distance; and D: the distance from the detection point to the traffic congestion point.

    As shown in the figure, when the particulate accumulation amount (a + b × D) of the filter 17 does not reach the predetermined amount α before reaching the traffic congestion point, the filter 17 is not forcibly regenerated during that period and enters the traffic congestion section. After that, the amount of particulates deposited on the filter 17 becomes a predetermined amount α or more. However, since the vehicle speed is low in the traffic jam section and the oxidation catalyst 16 is not activated, the forced regeneration cannot be performed, and even if the forced regeneration is started, the particulates of the filter 17 cannot be burned and the particulates of the filter 17 are not burned. The amount of deposition increases, causing clogging.

    Even when the particulate regeneration amount (a + b × D) of the filter 17 exceeds the predetermined amount α and the forced regeneration is started before reaching the traffic congestion point, if the vehicle enters the traffic congestion section, the vehicle speed decreases. As a result, the activity of the oxidation catalyst 16 is reduced, and the filter 17 is not regenerated, which causes clogging.

    On the other hand, in the case of the present embodiment, even when the particulate accumulation amount of the filter 17 is not equal to or greater than the predetermined amount α, the travel distance L (= (a + b × D−second predetermined amount)) for which forced regeneration is to be performed. ÷ c) is calculated, the time when the vehicle reaches a distance L from the traffic jam point is set as the regeneration start time, and the forced regeneration is executed until the traffic jam point is reached. Accordingly, as indicated by arrows in FIG. 7, the amount of particulates deposited on the filter 17 decreases from the regeneration start time, and when reaching the traffic congestion point, the amount of particulates accumulated becomes the second predetermined amount.

    Therefore, it is possible to enter the traffic congestion section with the particulate accumulation amount M of the filter 17 being small, and furthermore, since the EGR cut is performed in this traffic congestion section, an increase in the particulate emission amount of the engine can be suppressed. Therefore, in the traffic jam section, the amount of particulates deposited on the filter 17 is prevented from exceeding the predetermined amount α that is the forced regeneration start threshold, and clogging due to the inability to perform the forced regeneration of the filter 17 is avoided.

    In addition, the detection of traffic congestion information is slow, or the amount of particulate accumulation on the filter at the time of detection is already large, and when the regeneration start point is obtained by the above calculation, the vehicle has passed the regeneration start point. May be later. However, in this case as well, not only when the reproduction start point is reached in step B12, but also when it is determined that the reproduction start point has been passed, the process proceeds to step B13, so that forced regeneration is executed. .

    In the present embodiment as well, as in the first embodiment, the processing after step B10 may be performed only when traveling on a highway.

    In addition, the second predetermined amount may be set to a smaller value as the degree of traffic congestion is significant.

    Further, in the above embodiment, when the traffic congestion point is reached, the particulate accumulation amount of the filter 17 is set to the second predetermined amount. However, based on the temperature of the oxidation catalyst 16, the host vehicle enters the traffic congestion section. Thereafter, as long as the oxidation catalyst 16 maintains the activation temperature, the forced regeneration may be continued so that the amount of particulates deposited on the filter 17 becomes equal to or less than the second predetermined amount.

    Also, in the above embodiment, when traffic jam related information is obtained, the forced regeneration start time is determined so that the forced regeneration ends when the traffic congestion point is reached. When this is done, the forced regeneration may be immediately executed for the travel distance L, and the forced regeneration may be terminated before reaching the traffic congestion point. Even in that case, the amount of particulates deposited on the filter 17 becomes the second predetermined amount when the traffic congestion point is reached.

    In addition, as described above, if the traffic regeneration related information is obtained and the forced regeneration is executed immediately for the travel distance L, the traffic congestion section may extend to the near side (to the own vehicle side). Even if it exists, it will be advantageous when the forced regeneration is terminated before entering the traffic jam section, and the transition to the traffic jam section is performed in a state where the particulate accumulation amount is not more than the second predetermined amount.

    Further, in the above embodiment, the road is divided into three types of highways, suburban roads, and urban roads, and the particulate emission amount b and the particulate combustion amount c are set based on the map information. The particulate emission amount b and the particulate combustion amount c may be corrected based on other parameters (for example, traffic lights per unit distance, number of intersections, road gradient, etc.) obtained from the map information relating to the amount. Alternatively, it may be divided into an expressway and other general roads, and for general roads, the particulate emission amount b and the particulate combustion amount c may be set according to traffic lights per unit distance, the number of intersections, road gradients, and the like.

    In the first and second embodiments, the oxidation catalyst 16 is disposed on the upstream side of the filter 17 in order to increase the temperature of the filter 17 by the fuel injection control. By providing the above, the oxidation catalyst 16 may be omitted. Of course, the oxidation catalyst 16 may be disposed on the upstream side of the filter 17, and a catalytic metal may be supported on the filter 17 to have the function of an oxidation catalyst.

    In addition, an electric heater may be provided immediately before the filter 17 without providing the oxidation catalyst as described above, and the temperature of the filter 17 may be increased by energization from a vehicle-mounted battery. Alternatively, the electric heater and the above-described oxidation catalyst ( (Fuel injection control) may be combined.

    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 1, 2 is a case where a filter is DPF, this invention is applicable also when collecting 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. 3 is a control block diagram according to Embodiment 1. FIG. It is a control flow figure concerning the embodiment. It is a time chart figure of control concerning the embodiment. 6 is a control block diagram according to Embodiment 2. FIG. It is a control flow figure concerning the embodiment. It is a time chart figure of control concerning the embodiment.

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 Threshold value changing means 44 EGR control means 52 to 54 Current position detection means for own vehicle 56 Input means 57 Map information storage means 59, 60 Road traffic information receiving means 63 Reproduction control changing means

Claims (8)

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;
While the vehicle is running, the filter is configured so that the particulates collected by the filter are combusted when the particulate amount of the filter exceeds a predetermined amount based on the detection value of the particulate amount detection means. An exhaust emission control device for an engine comprising a forced regeneration means for forcibly regenerating the filter by raising the temperature of the filter,
Means for detecting the current location of the host vehicle, map information storage means, means for inputting the travel destination of the host vehicle, and means for receiving road traffic information are provided. Based on the map information by inputting the travel destination. A navigation system that sets a travel route to the destination and provides road traffic information;
Threshold value changing means for reducing the predetermined amount for starting execution of the forced regeneration means when the navigation system obtains road traffic information related to the occurrence of traffic congestion on the travel route. An exhaust purification device for an engine characterized by the above. In claim 1,
The engine exhaust gas purification apparatus, wherein the threshold value changing means reduces the predetermined amount only when the host vehicle is traveling on a highway. 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;
While the vehicle is running, the filter is configured so that the particulates collected by the filter are combusted when the particulate amount of the filter exceeds a predetermined amount based on the detection value of the particulate amount detection means. An exhaust emission control device for an engine comprising a forced regeneration means for forcibly regenerating the filter by raising the temperature of the filter,
Means for detecting the current location of the host vehicle, map information storage means, means for inputting the travel destination of the host vehicle, and means for receiving road traffic information are provided. Based on the map information by inputting the travel destination. A navigation system that sets a travel route to the destination and provides road traffic information;
Regeneration that activates the forced regeneration means regardless of whether or not the amount of fine particles in the filter is greater than or equal to a predetermined amount when road traffic information related to the occurrence of traffic congestion on the travel route is obtained by the navigation system Control change means ,
The regeneration control changing means operates the forced regeneration means so that the amount of fine particles in the filter is equal to or less than a second predetermined amount that is smaller than the predetermined amount at the occurrence point of the traffic jam . Exhaust purification device. In claim 3 ,
The regeneration control changing means comprises data defining the particulate emission amount of the engine per unit mileage and the particulate combustion amount of the filter per unit mileage when the forced regeneration means is operated, and from the current location of the own vehicle The distance to the traffic congestion point is determined based on the map information of the navigation system, and the current particle amount of the filter is set so that the particle amount of the filter is equal to or less than the second predetermined amount at the traffic congestion occurrence point. An exhaust emission control device for an engine, wherein the operation timing of the forced regeneration means is set based on the data on the particulate emission amount and particulate combustion amount and the distance. In claim 4 ,
The regeneration control changing means determines the particulate emission amount and particulate combustion amount for each road type, and determines the operation timing of the forced regeneration means according to the road type of the travel route obtained from the map information. An exhaust emission control device for an engine, wherein the particulate emission amount and the particulate combustion amount for setting are selected. In any one of Claims 3 thru | or 5 ,
The regeneration control changing means operates the forced regeneration means so that the particulate amount of the filter is equal to or less than a second predetermined amount smaller than the predetermined amount only when the host vehicle is traveling on an expressway. Exhaust gas purification device for the engine. In claim 2 or claim 6 ,
Exhaust gas recirculation amount adjusting means for adjusting the recirculation amount of exhaust gas recirculated to the intake system of the engine;
An engine having exhaust gas recirculation control means for prohibiting recirculation of the exhaust gas while the vehicle is traveling in a traffic jam section based on the map information and road traffic information of the navigation system. Exhaust purification device. In any one of Claims 1 thru | or 7 ,
The forced regeneration means is disposed upstream of the filter by injecting the fuel into the cylinder in an expansion stroke after the main injection in which the fuel is injected into the cylinder by an electric heater or near the top dead center of the compression stroke of the engine. An exhaust emission control device for an engine, characterized in that fuel is supplied to the oxidized catalyst and the temperature of the filter is raised by combustion reaction heat of the fuel in the oxidation catalyst.

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