JP2011032969A - Engine exhaust emission control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a power consumption caused by regeneration, in an engine exhaust emission control device including a regeneration means which is supplied with electric power from an external power supply in order to heat and regenerate a filter means. <P>SOLUTION: In a vehicle, a DPF is regenerated by an electrothermal heater supplied with the electric power from the external power supply in order to perform heating. Only if the temperature Tf of the DPF is higher than a first predetermined temperature T1 set lower than regenerable lowest temperature (S40) when performing connection to the external power supply (S20), electric power supply to the electrothermal heater is allowed (S130). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust emission control device for an engine, and more particularly to a regeneration technology for a filter that purifies exhaust gas.

  In order to collect and remove PM (particulate matter) whose main component is carbon contained in exhaust gas, diesel engines are widely equipped with DPF (diesel particulate filter) in the exhaust passage as an exhaust purification device. . In such a DPF, when PM is deposited, the trapping function is lowered and the pressure loss is increased. In view of this, a regenerating apparatus that heats and collects PM collected by the DPF to remove it by combustion is developed so as to recover the DPF collecting ability.

As a DPF regeneration apparatus, for example, an electric heater provided in the DPF is known. The electric heater heats the DPF by being supplied with electric power at an appropriate timing so that PM does not accumulate on the DPF beyond the tolerance.
As described above, in a regeneration device using an electric heater, power is normally supplied from a battery mounted on the vehicle. In order to reduce power consumption of the battery, power is supplied from an external power source when the vehicle is parked. A method for performing reproduction has also been developed (Patent Document 1).

Japanese Utility Model Publication No. 6-49717

However, the temperature of the DPF at the start of vehicle parking varies greatly depending on the surrounding environment or the driving situation up to that point. Therefore, in the regeneration device described in Patent Document 1, when regeneration is started in a state where the temperature of the DPF is lowered, power is consumed significantly to raise the DPF to a recyclable temperature, which is economical. It is not preferable from a viewpoint.
The present invention has been made to solve such problems, and an object of the present invention is to provide an engine exhaust purification device having a regeneration means for regenerating the filter means by being supplied with electric power from an external power source and heated. Is to suppress power consumption due to reproduction.

  In order to achieve the above object, an exhaust emission control device for an engine according to claim 1 of the present invention is provided in an exhaust passage of an engine of a vehicle, and includes filter means for capturing particulate matter in the exhaust, and electric power from an external power source. Heating means for heating the filter means and burning the trapped particulate matter to regenerate the filter means, temperature detection means for detecting the temperature of the filter means, and filter means detected by the temperature detection means And a regeneration control means for permitting the supply of electric power from the external power source to the heating means only when the temperature is equal to or higher than the first predetermined temperature.

An engine exhaust gas purification apparatus according to claim 2 of the present invention is the plug-in hybrid vehicle according to claim 1, wherein the vehicle is a plug-in hybrid vehicle including a battery that is charged with electric power supplied from an external power source. The filter means is heated to regenerate when the battery is charged.
According to a third aspect of the present invention, there is provided an exhaust emission control device for an engine according to the second aspect, further comprising a charge amount estimating means for estimating a charge amount of the battery, wherein the regeneration control means is a battery charge estimated by the charge amount estimating means. When the charging amount is equal to or less than the first predetermined amount, the supply of electric power to the heating unit is regulated regardless of the temperature of the filter unit.

  According to a fourth aspect of the present invention, there is provided an exhaust emission control device for an engine according to the second aspect, further comprising a deposit amount estimating means for estimating a deposit amount of particulate matter in the filter means, wherein the regeneration control means is a deposit amount estimating means. When the accumulated amount of the particulate matter estimated by the above is equal to or more than the second predetermined amount, the power supply from the external power source to the heating unit is permitted regardless of the temperature of the filter unit.

According to a fifth aspect of the present invention, there is provided an exhaust purification apparatus for an engine according to any one of the first to fourth aspects, wherein the regeneration control means includes a filter means detected by the temperature detecting means during regeneration of the filter means by the regeneration means. When the temperature continues for a predetermined time or longer and is lower than the second predetermined temperature, the supply of power to the regenerating means is restricted.
According to a sixth aspect of the present invention, the engine exhaust gas purification apparatus according to any one of the first to fifth aspects further comprises a supercharger that supplies air to the filter means during regeneration by the regeneration means. .

  According to the exhaust purification system for an engine of claim 1 of the present invention, since the supply of electric power to the heating means is permitted only when the temperature of the filter means is equal to or higher than the first predetermined temperature, the temperature of the filter means is Reproduction is restricted in the lowered state. Therefore, the temperature of the filter means is not raised above the first predetermined temperature by the heating means during regeneration, and power consumption during regeneration can be suppressed.

  According to the engine exhaust gas purification apparatus of the second aspect of the present invention, in the plug-in hybrid vehicle that regenerates the filter means when the battery is charged by the external power source, the regeneration is restricted when the temperature of the filter means is low. Therefore, power consumption due to regeneration during battery charging can be suppressed, power to be used for charging the battery can be secured, and increase in battery charging time associated with regeneration can be suppressed.

  According to the engine exhaust gas purification apparatus of the third aspect of the present invention, in the plug-in hybrid vehicle, when the charge amount of the battery is reduced to the first predetermined amount or less, the heating is performed regardless of the temperature of the filter means. Since the supply of power to the means is restricted, the charging of the battery has priority over the regeneration of the filter means. Therefore, it is possible to quickly eliminate the decrease in the charge amount of the battery and to secure the vehicle running function.

According to the exhaust emission control device for an engine of claim 4 of the present invention, in the plug-in hybrid vehicle, when the amount of particulate matter deposited on the filter means is equal to or larger than the second predetermined amount, the temperature is controlled by the filter means. Since power supply to the heating means is permitted, regeneration is prioritized over battery charging, and exhaust purification performance can be ensured.
According to the engine exhaust gas purification apparatus of the fifth aspect of the present invention, the particulate matter is not deposited on the regeneration means because the filter means does not reach the second predetermined temperature even when heated by the regeneration means for a predetermined time. Can be determined. By restricting the supply of power to the regeneration means, it is possible to reliably determine the end of regeneration and terminate the heating by the heating means, thereby preventing wasteful power consumption during regeneration.

  According to the engine exhaust gas purification apparatus of claim 6 of the present invention, air can be supplied to the filter means by operating the supercharger at the time of regeneration, so that it can be utilized as combustion air at the time of regeneration. it can. Therefore, regeneration is possible even when the engine is stopped, and particularly in a plug-in hybrid vehicle, regeneration can be reliably performed when the battery is charged. Moreover, the temperature control of the filter means at the time of regeneration can be facilitated by controlling the blower amount of the supercharger.

  Furthermore, even when the engine is stopped by supplying air from the supercharger, it is possible to detect the pressure loss of the filter means and estimate the amount of particulate matter deposited. Therefore, it is possible to easily determine the reproduction end time.

1 is a schematic configuration diagram of a plug-in hybrid vehicle equipped with an exhaust emission control device according to the present invention. It is a block diagram which shows the structure of the reproducing | regenerating apparatus of DPF. It is a flowchart which shows the control point of the electric heater in a reproduction | regeneration control apparatus. It is a map for power supply amount setting.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a plug-in hybrid vehicle equipped with an exhaust purification device according to the present invention.
As shown in FIG. 1, a battery 2, an electric motor 3, an engine 4, a generator 5, and a power supply device 6 are mounted on a plug-in hybrid vehicle (hereinafter simply referred to as a vehicle 1).

  The drive wheels 7 of the vehicle 1 are driven by the electric motor 3. The electric motor 3 is supplied with electric power from the battery 2 via the control device 8 and can be driven. The battery 2 can be charged from an external power supply (commercial power supply) via a power supply device 6 (charger), and can be charged by being supplied with electric power from a generator 5 driven by an engine 4 mounted on the vehicle 1. It has a configuration.

Since the engine 4 is used only for power generation, a diesel engine suitable for use at a low speed and a substantially constant rotational speed is employed.
A DPF (diesel particulate filter) (filter means) 11 is interposed in the exhaust passage 10 of the engine 4 as an exhaust purification device.
The DPF 11 has a function of collecting PM (particulate matter) in the exhaust gas by alternately closing the upstream side and the downstream side of the honeycomb carrier passage with plugs, and further forms a passage. The porous wall is formed by supporting a catalytic noble metal such as platinum (Pt), palladium (Pd), rhodium (Rh).

The DPF 11 is provided with an electric heater 12 (heating means). The electric heater 12 generates heat when supplied with electric power, and has a function of burning and removing PM collected in the DPF 11 to regenerate the DPF 11. Further, the DPF 11 is provided with a DPF temperature sensor 13 (temperature detection means) that detects the temperature of the DPF 11.
FIG. 2 is a block diagram showing the configuration of the DPF 11 regeneration device.

As shown in FIG. 2, the regeneration device for the DPF 11 includes the battery 2, the power supply device 6, the control device 8 (regeneration control means), the electric heater 12, the DPF temperature sensor 13, an external power supply connection device 20, and an external power supply. A connection detection device 21 and a charge control device 22 are provided.
The external power connection device 20 is specifically a power cord having a power plug at the tip. This power plug can be connected to an external power source by being inserted into a receptacle installed on a building wall or the like.

The external power connection detection device 21 has a function of determining whether or not the power plug is connected to the receptacle, that is, whether or not charging from the external power source is possible. The external power connection detection device 21 detects whether or not the power plug is connected, for example, by detecting power supply to the power device 6 by connecting a power plug.
The power supply device 6 is mainly composed of an inverter having a function of converting AC power into DC power.

The charge control device 22 has a function of, for example, integrating the charge / discharge amount to the battery 2 and detecting the current charge amount B of the battery 2.
The control device 8 includes an input / output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), and a timer 8a. The plug connection information and the temperature of the DPF 11 detected by the DPF temperature sensor 13 are input, and the power supply to the electric heater 12 is controlled.

FIG. 3 is a flowchart showing the control procedure of the electric heater 12 in the control device 8.
This flowchart operates when the key switch is ON or when the control device 8 is powered on.
As shown in FIG. 3, first, in step S10, connection information with an external power source is input from the external power source connection detection device 21. That is, information on whether the power plug is inserted into the receptacle and is electrically connected is input. Then, the process proceeds to step S20.

In step S20, the connection information with the external power source input in step S10 is input, and it is determined whether or not the external power source is connected. If it is connected to an external power supply, the process proceeds to step S30.
In step S30, the DPF temperature Tf is input from the DPF temperature sensor 13. Then, the process proceeds to step S40.

In step S40, it is determined whether or not the DPF temperature Tf input in step S30 is equal to or higher than a first predetermined temperature T1. The first predetermined temperature T1 may be set lower than the lowest temperature that can be regenerated in the DPF 11 (the lowest temperature that can be regenerated), and is set to 250 ° C., for example. If the DPF temperature Tf is equal to or higher than the first predetermined temperature T1, the process proceeds to step S50.
In step S50, it is determined whether or not the DPF temperature Tf input in step S30 is equal to or lower than the regeneration target temperature Tt. The regeneration target temperature Tt may be set to a temperature at which regeneration is performed efficiently. For example, the regeneration target temperature Tt may be set to 650 ° C., or may be set by correcting this value according to the regeneration state such as the exhaust flow rate. . If the DPF temperature Tf is equal to or lower than the regeneration target temperature Tt, the process proceeds to step S60.

In step S60, a difference Tt−Tf between the regeneration target temperature Tt and the DPF temperature Tf input in step S30 is calculated. Then, the process proceeds to step S70.
In step S70, the amount of electric power W supplied to the electric heater 12 is calculated based on the difference Tt−Tf between the regeneration target temperature calculated in step S60 and the DPF temperature. The amount of power supply W is calculated using, for example, a map as shown in FIG. As shown in FIG. 4, the supplied power amount W is set to have a proportional relationship that increases as the difference Tt−Tf between the regeneration target temperature and the DPF temperature increases. The maximum supply power amount (rated power) of the electric heater 12 is the minimum temperature (for example, 400 ° C.) at which the DPF 11 in the state where the predetermined amount of PM that needs to be regenerated is accumulated from the first predetermined temperature T1. ) Is set to be able to rise. Then, the supplied power amount W is supplied to the electric heater 12 to heat the DPF 11, and the process proceeds to step S80.

In step S80, it is determined whether or not the DPF temperature Tf input in step S30 is equal to or lower than a second predetermined temperature T2. The second predetermined temperature T2 may be set to the lowest reproducible temperature in the DPF 11, and may be set to 400 ° C., for example. If the DPF temperature Tf is equal to or lower than the second predetermined temperature T2, the process proceeds to step S90.
In step S90, it is determined whether or not the value counted by the timer 8a is equal to or greater than a predetermined value T3. The predetermined value T3 may be set so that it can be determined whether or not a time (predetermined time) slightly longer than the time lag between the start of heating by the electric heater 7 and the actual temperature rise of the DPF 11 has elapsed. If the count value of the timer 8a is not equal to or greater than the predetermined value T3, the process proceeds to step S100.

In step S100, the timer 8a is counted up. Then, this routine is returned.
If it is determined in step S80 that the DPF temperature Tf is higher than the second predetermined temperature T2, the process proceeds to step S110.
In step S110, the timer 8a is reset to zero. Then, this routine is returned.

If it is determined in step S40 that the DPF temperature Tf is not equal to or higher than the first predetermined temperature T1, the process proceeds to step S120.
In step S120, it is determined whether or not the count value of the timer 8a is greater than zero. If the count value of the timer 8a is greater than 0, the process proceeds to step S50. When the count value of the timer 8a is 0 or less, the process proceeds to step S130.

If it is determined in step S50 that the DPF temperature Tf is greater than the regeneration target temperature Tt, or if it is determined in step S90 that the count value of the timer 8a is equal to or greater than the predetermined value T3, the process proceeds to step S130.
In step S130, the supply of electric power to the electric heater 12 is stopped. Then, the process proceeds to step S140.

In step S140, the timer 8a is reset to zero. Then, this routine is returned.
By controlling as described above, in the present embodiment, when the external power supply is connected, the temperature of the DPF 11 is detected, and when the temperature is lower than the first predetermined temperature T1 set lower than the lowest reproducible temperature of the DPF 11. While the electric power supply to the electric heater 12 is restricted, when the temperature is equal to or higher than the first predetermined temperature T1, the electric power supply to the electric heater 12 is allowed and regeneration is possible. That is, regeneration is restricted when the temperature of the DPF 11 is lowered when the external power supply is connected, and regeneration is performed when the DPF 11 is warm. Therefore, it is not necessary to greatly increase the DPF temperature for regeneration, and thus power consumption in regeneration can be suppressed. In particular, the present embodiment is adopted in a plug-in hybrid vehicle, and regeneration is performed when the battery 2 is charged. Therefore, power supplied for charging the battery 2 is ensured by suppressing power consumption during regeneration. It is possible to suppress the extension of the battery charging time due to regeneration.

Further, in this embodiment, if the timer is counted even if the temperature Tf of the DPF 11 is not equal to or higher than the first predetermined temperature Tt, the power supply to the electric heater 12 is not immediately stopped and the process goes to step S50. Therefore, the power supply is stopped only in a state where the temperature change has subsided during the temperature rise control. Therefore, the control of the electric heater 13 is stably performed.
At the time of regeneration, the supply power amount W to the electric heater 12 is controlled based on the difference between the temperature Tf of the DPF 11 and the regeneration target temperature Tt. Specifically, the supply power amount W is proportional to the value of Tt−Tf. Is set to an appropriate value such that the temperature of the DPF 11 becomes the regeneration target temperature Tt, and efficient regeneration with reduced power consumption can be performed.

  In the present embodiment, the rated power of the electric heater 12 is set to a value that does not reach the second predetermined temperature T2 even when the DPF 11 in a state where PM is not deposited is heated by the electric heater 12. . Since the heating by the electric heater 12 is controlled to stop when the temperature of the DPF 11 becomes equal to or lower than the second predetermined temperature T2 at the time of regeneration, the electric heater 12 when the PM deposition amount becomes zero. Thus, it is possible to reliably stop heating and prevent wasteful power consumption.

  Moreover, in the said embodiment, you may make it the structure which enables reproduction | regeneration by the electric power supply from the battery 2 also during engine operation. In such a configuration, even when the engine 4 is stopped during the regeneration during the engine operation, the regeneration can be continued by the external power source using the state where the DPF 11 is heated. And efficient reproduction is possible.

  Furthermore, the control device 8 supplies power to the electric heater 12 regardless of the temperature of the DPF 11 when the charge amount B of the battery 2 detected by the charge control device 22 is equal to or less than the first predetermined amount B1. It is good to regulate. The first predetermined amount B1 may be set in the vicinity of the lower limit within the range of the charge amount of the battery 2 that does not interfere with vehicle travel. In this way, the electric power supplied from the external power source is used in preference to the charging of the battery 2 over the regeneration of the DPF 11, so that the decrease in the charging amount of the battery 2 can be quickly resolved and the vehicle running performance is ensured. can do.

  Further, the controller 8 is provided with a deposition amount estimation unit 8b (deposition amount estimation means) for estimating the PM deposition amount Qp in the DPF 11, and when the PM deposition amount Qp is equal to or larger than the second predetermined amount Qp2, the DPF 11 Regeneration may be performed regardless of the temperature. The second predetermined amount Qp2 may be set to a value at which the exhaust performance becomes unsuitable for traveling. The PM accumulation amount Qp may be obtained, for example, by calculating from the pressure difference before and after the DPF 11 or by integrating the operating state of the engine 4 such as the accelerator opening and the operating time. By controlling in this way, regeneration is prioritized over charging of the battery 2, and exhaust purification performance can be ensured.

  Further, when the PM accumulation amount Qp is large, the power supply amount W supplied to the electric heater 12 is small, and when the PM accumulation amount Qp is small, the power supply amount W supplied to the electric heater 12 is corrected to be large. When the amount of accumulated PM is large, the temperature of the DPF 11 greatly increases due to the combustion of PM during regeneration, so that the amount of power W supplied to the distribution heater 12 can be reduced, thus saving power consumption. Can do.

  Further, as shown in FIG. 1, in the present embodiment, the engine 4 includes a supercharger 40. As the supercharger 40, an electric supercharger that drives a compressor by an electric motor is used. The operation of the electric motor of the supercharger 40 is controlled by the control device 8. The supercharger 40 is normally controlled in accordance with the load and rotation speed of the engine 4 and has a function of increasing the engine torque by increasing the intake air amount of the engine 4. In the present embodiment, the control device 8 further controls the supercharger 40 to operate when the DPF 11 is regenerated. By operating the supercharger 40, air passes through the combustion chamber of the engine 4 and flows into the exhaust passage 10 and is supplied to the DPF 11, so that it is used as combustion air during regeneration. Thereby, it becomes easy to burn PM, and regeneration efficiency can be improved. Further, by controlling the operation of the supercharger 40 and controlling the air flow rate, it becomes possible to easily control the temperature of the DPF 11 during regeneration. In particular, by using an electric supercharger, regeneration can be efficiently performed even when the engine is stopped. Further, by supplying air to the DPF 11 by the operation of the supercharger 40, it is possible to detect the pressure loss of the DPF 11 and estimate the PM accumulation amount even when the engine 1 is stopped. An end determination can be made.

2 Battery 4 Engine 8 Controller 8b Accumulation amount estimation unit 11 DPF
12 Electric Heater 13 DPF Temperature Sensor 40 Supercharger

Claims (6)

A filter means provided in an exhaust passage of a vehicle engine for capturing particulate matter in the exhaust;
Heating means supplied with electric power from an external power source to heat the filter means, burn the trapped particulate matter, and regenerate the filter means;
Temperature detecting means for detecting the temperature of the filter means;
A regeneration control means that permits the supply of power from the external power source to the heating means only when the temperature of the filter means detected by the temperature detection means is equal to or higher than a first predetermined temperature;
An exhaust purification device for an engine characterized by comprising: The vehicle is a plug-in hybrid vehicle including a battery that is charged by being supplied with electric power from the external power source,
The engine exhaust purification apparatus according to claim 1, wherein the heating means heats the filter means to regenerate the battery when it is charged. A charge amount estimating means for estimating a charge amount of the battery;
The regeneration control means regulates the supply of power to the heating means regardless of the temperature of the filter means when the charge amount of the battery estimated by the charge quantity estimation means is equal to or less than a first predetermined amount. The exhaust emission control device for an engine according to claim 2, wherein: A deposition amount estimating means for estimating a deposition amount of particulate matter in the filter means;
When the accumulation amount of the particulate matter estimated by the accumulation amount estimation unit is equal to or greater than a second predetermined amount, the regeneration control unit is supplied from the external power source to the heating unit regardless of the temperature of the filter unit. The engine exhaust purification device according to claim 2, wherein supply of electric power is permitted.   The regeneration control means, when the regeneration means regenerates the filter means, if the temperature of the filter means detected by the temperature detection means continues for a predetermined time or longer and is lower than a second predetermined temperature, the regeneration control means The engine exhaust gas purification apparatus according to any one of claims 1 to 4, wherein supply of electric power to the means is restricted.   The engine exhaust gas purification apparatus according to any one of claims 1 to 5, further comprising a supercharger for supplying air to the filter means during regeneration by the regeneration means.

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