JP5757066B2 - DPF regeneration control device - Google Patents

Description

 The present invention relates to a DPF (Diesel Particulate Filter) regeneration control device.

  As is well known, a DPF for collecting particulate matter (PM) such as soot contained in exhaust gas is installed in an exhaust system of a diesel engine. When the amount of accumulated soot in the DPF increases, exhaust gas purification performance and back pressure increase, and so it is necessary to regenerate the DPF by burning and removing soot adhering to the DPF periodically. In recent years, it is common to automatically regenerate a DPF using an electronic control device (see Patent Document 1 below).

JP 2005-90359 A

  On the other hand, the applicant of the present invention can estimate the soot accumulation amount during regeneration of the DPF and display the estimation result so that the user can recognize the regeneration state of the DPF (PM accumulation amount calculation display of the diesel engine) (Apparatus) (application number: Japanese Patent Application No. 2009-275595). Since the present invention only displays the soot accumulation amount of the DPF, the user cannot determine when the regeneration of the DPF is finished, and it is necessary to interrupt other work until the completion of the regeneration of the DPF. Will be reduced.

 The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a DPF regeneration control apparatus capable of improving the work efficiency of a user during regeneration of a DPF.

  In order to solve the above-mentioned problems, the present invention provides a DPF regeneration control device that regenerates the DPF by controlling the supply of combustion gas to the DPF by a burner as a first solution means related to the DPF regeneration control device. An input unit for inputting sensor detection values necessary for estimating the PM accumulation amount and the PM decrease amount of the DPF, and the sensor obtained from the input unit at a constant estimation period from the regeneration start time of the DPF. Based on the detected value, the PM accumulation amount and the PM decrease amount of the DPF are estimated, and a calculation unit for calculating the remaining time until the regeneration of the DPF is completed based on the estimation result, and the calculation result of the remaining time are displayed. And an output unit for outputting display data necessary for the output to an external display device.

In the present invention, as the second solving means related to the DPF regeneration control device, in the first solving means, the calculation unit estimates the PM accumulation amount when the inlet temperature of the DPF is equal to or higher than a target temperature. Based on the following formula (1) consisting of the result Q, the PM accumulation amount Q0 to be regenerated, the estimated result D of the PM decrease amount, the estimated period ΔT, and the time TB required for the burner extinguishing process, The remaining time TE is calculated.
TE = (Q−Q0) / D · ΔT + TB (1)

Further, in the present invention, as a third solving means related to the DPF regeneration control device, in the first solving means, the calculation unit estimates the PM accumulation amount when the inlet temperature of the DPF is lower than a target temperature. Result Q, PM accumulation amount Q0 at the end of regeneration, PM reduction amount estimation result D1 with respect to the target temperature, estimation period ΔT, estimated time TR until the inlet temperature reaches the target temperature, and time TB required for burner extinguishing processing The remaining time TE until the end of regeneration of the DPF is calculated on the basis of the following equation (2).
TE = (Q−Q0) / D1 · ΔT + TR + TB (2)

Further, in the present invention, as a fourth solving means related to the DPF regeneration control device, in the first solving means, when the fire extinguishing process of the burner is started, the calculation unit starts from the start time of the extinguishing process. The remaining time TE until the end of regeneration of the DPF is calculated on the basis of the following equation (3) consisting of the elapsed time TP up to now and the time TB required for the burner fire extinguishing process.
TE = TB-TP (3)

 In the present invention, as a fifth solving means relating to the DPF regeneration control device, in any one of the first to fourth solving means, the sensor detection value includes an engine speed, an engine load, and an inlet of the DPF. The temperature is included.

 According to the DPF regeneration control device according to the present invention, in order to calculate the remaining time from the regeneration start time of the DPF to the regeneration end at a constant estimation cycle, and to output display data indicating the calculation result to an external display device, It is possible to display the remaining time until the end of DPF regeneration on the display screen of the display device. As a result, the user can recognize the remaining time until the end of the DPF regeneration, so that the remaining time can be used effectively such as performing another work until the end of the DPF regeneration. It is possible to improve the work efficiency of the user inside.

1 is a schematic configuration diagram of an exhaust gas purification system including a DPF regeneration control device in the present embodiment. FIG. 3 is a characteristic diagram showing the amount of soot generated per unit time by the diesel engine 1. It is a characteristic view which shows the correspondence between the inlet temperature Tin of DPF3, and the amount of soot reduction per unit time. It is a figure which shows the time transition of the inlet_port | entrance temperature Tin of DPF3 in the period from the reproduction | regeneration start time ts of DPF3 to the reproduction | regeneration end time (extinguishing process end time of the burner 4) te.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an exhaust gas purification system provided with a DPF regeneration control device in the present embodiment. As shown in FIG. 1, the exhaust gas purification system in this embodiment includes a diesel engine 1, an exhaust pipe 2, a DPF 3, a burner 4, a temperature sensor 5, a rotation speed sensor 6, a load sensor 7, a display device 8, and a DPF regeneration. The controller 9 is configured.

  The diesel engine 1 compresses air sucked into a combustion chamber of a cylinder through an intake pipe (not shown) by ascending a piston, and injects fuel into the combustion chamber from an injector disposed in an upper portion of the combustion chamber. This is a 4-cycle engine that generates combustion gas and obtains rotational power of an output shaft (crankshaft). An exhaust pipe 2 is connected to the exhaust port of the diesel engine 1, and the combustion gas generated in the combustion stroke is discharged to the outside through the exhaust pipe 2 as exhaust gas in the next exhaust stroke.

  A DPF 3 for collecting particulate matter (PM) such as soot contained in the exhaust gas is installed in the middle of the exhaust pipe 2. In addition, a burner 4 for regenerating the DPF 3 by burning and removing the soot adhering to the DPF 3 and a temperature sensor 5 for detecting the inlet temperature of the DPF 3 are installed in the front stage of the DPF 3 in the exhaust pipe 2. Has been. Note that an oxidation catalytic converter for oxidizing and purifying hydrocarbons and carbon monoxide contained in the exhaust gas is generally installed upstream of the DPF 3 in the exhaust pipe 2, but in FIG. The illustration is omitted.

  The burner 4 supplies combustion gas to the DPF 3 through the exhaust pipe 2 under the control of the DPF regeneration control device 9. Specifically, the internal space of the burner 4 communicates with the internal space (exhaust gas flow path) of the exhaust pipe 2, and a part of the exhaust gas discharged from the diesel engine 1 is introduced into the internal space of the burner 4. It is the composition which becomes. Further, the burner 4 is provided with an injector for injecting fuel toward the internal space, and a spark plug for generating a spark in the internal space (all not shown).

  That is, when the DPF 3 is regenerated, the DPF regeneration control device 9 controls the injector to supply fuel to the internal space of the burner 4 to generate a mixed gas of exhaust gas and fuel. Further, the DPF regeneration control device 9 performs ignition. Combustion gas supply to the DPF 3 by the burner 4 is realized by burning the mixed gas existing in the internal space of the burner 4 and generating high-temperature combustion gas by controlling the plug.

  The temperature sensor 5 detects the inlet temperature Tin of the DPF 3 and outputs the sensor detection value to the DPF regeneration control device 9. The rotational speed sensor 6 detects the rotational speed of the crankshaft that is the output shaft of the diesel engine 1 as the engine rotational speed N, and outputs the sensor detection value to the DPF regeneration control device 9.

  The load sensor 7 detects the engine torque of the diesel engine 1 as the engine load L, and outputs the sensor detection value to the DPF regeneration control device 9. The engine torque can be directly detected by installing a torque sensor in the engine power transmission mechanism. However, since there is a correlation between the fuel supply amount to the diesel engine 1 and the engine torque, the diesel engine 1 The engine torque may be detected indirectly by detecting the amount of fuel supplied to the engine.

  The display device 8 is, for example, a liquid crystal display device or an LED display device, and displays an image corresponding to display data input from the DPF regeneration control device 9.

  The DPF regeneration control device 9 is an ECU (Electronic Control Unit) that regenerates the DPF 3 by controlling the supply of combustion gas to the DPF 3 by the burner 4, and includes an input interface 9a, an A / D converter 9b, and a burner drive circuit 9c. An output interface 9d, a ROM (Read Only Memory) 9e, a RAM (Random Access Memory) 9f, and a CPU (Central Processing Unit) 9g are incorporated.

 The input interface 9a (input unit) is connected to the temperature sensor 5, the rotational speed sensor 6 and the load sensor 7, and sensor detection of the engine rotational speed N, the engine load L and the inlet temperature Tin of the DPF 3 input from each sensor. The value (analog value) is output to the A / D converter 9b. The A / D converter 9b converts each sensor detection value input from the input interface 9a into a digital value and outputs the digital value to the CPU 9g. When the CPU 9g is equipped with an A / D conversion function, it is not necessary to provide the A / D converter 9b.

  Under the control of the CPU 9g, the burner drive circuit 9c generates a burner drive signal necessary for operating the injector and spark plug of the burner 4 to supply combustion gas to the DPF 3, and outputs the generated burner drive signal. Output to interface 9d. The output interface 9d (output unit) is connected to the burner 4 and the display device 8, outputs the burner drive signal generated by the burner drive circuit 9c to the burner 4, and displays the display data generated by the CPU 9g. Output to the display device 8.

 The ROM 9e is a non-volatile memory that stores in advance control programs and various setting data for realizing various functions of the CPU 9g. The RAM 9f is a volatile working memory used as a temporary storage destination of data when the CPU 9g executes a control program stored in the ROM 9e to perform various operations.

  The CPU 9g (arithmetic unit) supplies combustion gas to the DPF 3 by the burner 4 based on the sensor detection values (engine speed N, engine load L, and inlet temperature Tin of the DPF 3) obtained from the A / D converter 9b. It has a function to control (a function to control regeneration of the DPF 3). Further, as a characteristic function in the present embodiment, the CPU 9g has a PM deposition amount of the DPF 3 based on each sensor detection value obtained from the A / D converter 9b at a constant estimation period from the start of the regeneration of the DPF 3. A function of estimating the amount of PM reduction, calculating the remaining time TE until the end of regeneration of the DPF 3 based on the estimation result, generating display data necessary for displaying the calculation result, and outputting the display data to the display device 8 Have.

  In the following, with reference to FIGS. 2 to 4, each process executed by the CPU 9g in order to realize the regeneration control function of the DPF 3 (the control function of the burner 4) and the function of calculating the remaining time TE until the end of regeneration will be described in detail. explain.

<Soot accumulation monitoring process>
First, the CPU 9g estimates the current soot accumulation amount of the DPF 3 based on the engine speed N and the engine load L obtained from the A / D converter 9b at a constant estimation period (for example, 1 second period). It is monitored whether the estimated soot accumulation amount exceeds a predetermined amount.

  FIG. 2 is a characteristic diagram showing the amount of soot generated per unit time by the diesel engine 1. As shown in FIG. 2, it can be seen that the amount of soot generated per unit time is uniquely determined from the engine speed N and the engine load L of the diesel engine 1. That is, the current soot accumulation amount of the DPF 3 can be calculated (estimated) by obtaining the soot generation amount per unit time from the sensor detection values of the engine speed N and the engine load L and accumulating at each estimation cycle. it can.

  In the present embodiment, table data indicating the correspondence relationship between the soot generation amount per unit time as shown in FIG. 2, the engine speed N and the engine load L is stored in the ROM 9e in advance, and the CPU 9g For each period, the soot generation amount per unit time corresponding to the engine speed N and the engine load L obtained from the A / D converter 9b is obtained from the table data and integrated to obtain the current soot accumulation amount of the DPF 3. Is estimated.

<DPF3 regeneration process>
In the above-described soot accumulation amount monitoring process, the CPU 9g instructs the burner drive circuit 9c to start generating a burner drive signal when the estimation result of the current soot accumulation amount exceeds a predetermined amount. At this time, supply of combustion gas to the DPF 3 by the burner 4 is started, and regeneration of the DPF 3 (soot combustion removal) is started.

  The CPU 9g estimates the soot accumulation amount at a constant estimation cycle even after the regeneration of the DPF 3 is started, and monitors whether or not the estimated soot accumulation amount has reached a preset soot accumulation amount at the end of regeneration. Here, the method for estimating the soot accumulation amount after the start of regeneration is slightly different from that before the start of regeneration as described below.

 FIG. 3 is a characteristic diagram showing a correspondence relationship between the inlet temperature Tin of the DPF 3 and the amount of soot reduction per unit time. As shown in FIG. 3, it can be seen that the amount of soot reduction per unit time is uniquely determined from the inlet temperature Tin of the DPF 3. That is, after the regeneration of the DPF 3 is started, the soot reduction amount per unit time is obtained from the sensor detection value of the inlet temperature Tin of the DPF 3 at a constant estimation cycle, and the soot accumulation amount obtained at the start of the regeneration of the DPF 3 is sequentially determined. By subtracting, the current soot accumulation amount can be calculated (estimated).

  In the present embodiment, table data indicating the correspondence between the inlet temperature Tin of the DPF 3 and the amount of soot reduction per unit time as shown in FIG. 3 is stored in the ROM 9e in advance, and the CPU 9g is configured to start the regeneration of the DPF 3. The soot reduction amount per unit time corresponding to the inlet temperature Tin of the DPF 3 obtained from the A / D converter 9b is obtained from the table data for each estimation period, and the soot accumulation amount obtained at the start of the regeneration of the DPF 3 The current soot accumulation amount of the DPF 3 is estimated by sequentially subtracting from.

<Fire extinguishing treatment of burner 4>
When the soot accumulation amount estimated as described above reaches the preset soot accumulation amount after the start of regeneration of the DPF 3, the CPU 9g stops generating the burner drive signal to the burner drive circuit 9c. And a dry-up for removing the mixed gas remaining in the burner 4 is performed (in FIG. 1, illustration of an apparatus necessary for the dry-up of the burner 4 is omitted).

  The CPU 9g recognizes the time point when the above-described fire extinguishing process of the burner 4 is finished (the time point when the dry-up is finished) as the regeneration end point of the DPF 3. Since the CPU 9g performs dry-up for a preset time, the time required for the fire extinguishing process of the burner 4 is almost the same as the dry-up time.

<Calculation processing of remaining time TE until playback ends>
In addition, after starting the regeneration of the DPF 3, the CPU 9g executes a calculation process of the remaining time TE until the regeneration ends in parallel with the regeneration process of the DPF 3 and the fire extinguishing process of the burner 4 described above. FIG. 4 is a diagram showing the time transition of the inlet temperature Tin of the DPF 3 in the period from the regeneration start time ts of the DPF 3 to the regeneration end time (the fire extinguishing process end time of the burner 4) te. In FIG. 4, t1 indicates a point in time when the inlet temperature Tin of the DPF 3 reaches the target temperature, and t2 indicates a point in time when the fire extinguishing process of the burner 4 is started.

In the period from t1 to t2 in FIG. 4, that is, when the inlet temperature Tin of the DPF 3 is equal to or higher than the target temperature, the CPU 9g estimates the soot accumulation amount estimation result Q, the soot accumulation amount Q0 to end regeneration, and the soot reduction amount estimation. Based on the following formula (1) consisting of the result D, the estimation period ΔT, and the time TB required for the fire extinguishing process of the burner 4, the remaining time TE until the end of regeneration of the DPF 3 is calculated.
TE = (Q−Q0) / D · ΔT + TB (1)

  In the above equation (1), the estimation result Q of the soot accumulation amount is a value obtained by the estimation method described in the regeneration process of the DPF 3. Further, the estimation result D of the soot reduction amount is the current inlet temperature Tin (sensor) obtained from the table data indicating the correspondence between the inlet temperature Tin of the DPF 3 and the soot reduction amount per unit time as shown in FIG. This is the amount of soot reduction per unit time corresponding to (detected value). The soot accumulation amount Q0, the estimated period ΔT, and the time TB required for the fire extinguishing process of the burner 4 are known values (set values).

Further, in the period from ts to t1 in FIG. 4, that is, when the inlet temperature Tin of the DPF 3 is lower than the target temperature, the CPU 9g determines the soot accumulation amount estimation result Q, the PM accumulation amount Q0 to be regenerated, and the target temperature. Based on the following equation (2) consisting of the estimation result D1 of the soot reduction amount, the estimation period ΔT, the estimated time TR until the inlet temperature Tin reaches the target temperature, and the time TB required for the fire extinguishing process of the burner 4, The remaining time TE until the end of reproduction is calculated.
TE = (Q−Q0) / D1 · ΔT + TR + TB (2)

  In the above equation (2), the estimation result D1 of the soot reduction amount relative to the target temperature corresponds to the target temperature obtained from the table data indicating the correspondence relationship between the inlet temperature Tin of the DPF 3 and the soot reduction amount per unit time. This is the amount of soot reduction per unit time. The predicted time TR until the inlet temperature Tin reaches the target temperature is a value estimated (calculated) from the temperature gradient of the inlet temperature Tin in the period from ts to t1 in FIG.

Further, in the period from t2 to te in FIG. 4, that is, when the fire extinguishing process of the burner 4 is started, the CPU 9g requires the elapsed time TP from the start time t2 of the fire extinguishing process to the present and the fire extinguishing process of the burner 4. Based on the following equation (3) consisting of time TB, the remaining time TE until the end of regeneration of the DPF 3 is calculated.
TE = TB-TP (3)

  When the CPU 9g calculates the remaining time TE for each estimated period from the reproduction start time of the DPF 3 according to the conditional branch as described above, the CPU 9g generates display data necessary for displaying the calculation result and outputs the display data to the display device 8. . Thereby, the remaining time TE from the current time until the end of the reproduction of the DPF 3 is displayed on the display screen of the display device 8, and the displayed remaining time TE is sequentially updated for each estimation period.

  As described above, according to the DPF regeneration control device 9 of the present embodiment, the remaining time TE from the regeneration start time of the DPF 3 to the regeneration end is calculated at a constant estimation cycle, and the display data indicating the calculation result is externally displayed. Therefore, the remaining time TE until the end of the regeneration of the DPF 3 can be displayed on the display screen of the display device 8. As a result, the user can recognize the remaining time TE until the end of the regeneration of the DPF 3, so that the remaining time TE can be used effectively such as performing another work until the end of the regeneration of the DPF 3. It is possible to improve the user's work efficiency during the reproduction of.

In addition, this invention is not limited to the said embodiment, The following modifications are mentioned.
(1) In the above embodiment, the case where the engine speed N, the engine load L, and the inlet temperature Tin of the DPF 3 are used as sensor detection values necessary for estimating the soot accumulation amount and the soot reduction amount of the DPF 3 is described. The present invention is not limited to this, and other sensor detection values may be used as long as the soot accumulation amount and the soot reduction amount of the DPF 3 can be estimated.

(2) Instead of displaying only the number of the remaining time TE on the display screen of the display device 8, a time transition curve of the inlet temperature Tin of the DPF 3 as shown in FIG. A function for generating display data may be mounted on the CPU 9g so that it corresponds to any time point above and the remaining time TE at that time point is displayed. As a result, the user can more intuitively recognize the remaining time TE until the end of the reproduction of the DPF 3.

 DESCRIPTION OF SYMBOLS 1 ... Diesel engine, 2 ... Exhaust pipe, 3 ... DPF, 4 ... Burner, 5 ... Temperature sensor, 6 ... Revolution sensor, 7 ... Load sensor, 8 ... Display apparatus, 9 ... DPF regeneration control apparatus, 9a ... Input interface (Input unit), 9b ... A / D converter, 9c ... Burner drive circuit, 9d ... Output interface (output unit), 9e ... ROM, 9f ... RAM, 9g ... CPU (calculation unit)

Claims (4)

A DPF regeneration control device that regenerates the DPF by controlling the supply of combustion gas to the DPF by a burner,
An input unit for inputting a sensor detection value including an engine speed, an engine load, and an inlet temperature of the DPF necessary for estimating the PM accumulation amount and the PM decrease amount of the DPF;
The PM accumulation amount of the DPF is estimated on the basis of the sensor rotation speed and the sensor detection value of the engine load obtained from the input unit at a constant estimation cycle from the regeneration start time of the DPF, and the inlet temperature of the DPF Calculating a PM decrease amount using table data indicating the relationship between the DPF and the PM decrease amount per unit time of the DPF, and calculating a remaining time until the end of regeneration of the DPF based on the estimation result;
An output unit for outputting display data necessary for displaying the calculation result of the remaining time to an external display device, and
When the inlet temperature of the DPF is equal to or higher than a target temperature, the calculation unit estimates the PM reduction amount using the table data based on a sensor detection value of the inlet temperature of the DPF obtained from the input unit,
When the DPF inlet temperature is lower than a target temperature, the PM reduction amount is estimated using the table data on the assumption that the DPF inlet temperature is the target temperature. When the inlet temperature of the DPF is equal to or higher than the target temperature, the calculation unit determines the PM accumulation amount estimation result Q, the PM accumulation amount Q0 to be regenerated, the PM decrease amount estimation result D, the estimation period ΔT, and the burner 2. The DPF regeneration control apparatus according to claim 1, wherein a remaining time TE until the completion of regeneration of the DPF is calculated based on the following equation (1) including a time TB required for fire extinguishing processing.
TE = (Q−Q0) / D · ΔT + TB (1) When the inlet temperature of the DPF is lower than the target temperature, the calculation unit determines the PM deposition amount estimation result Q, the regeneration PM termination amount Q0, the PM decrease amount estimation result D1 with respect to the target temperature, the estimation period ΔT, The remaining time TE until the end of regeneration of the DPF is calculated on the basis of the following equation (2) consisting of a predicted time TR until the inlet temperature reaches the target temperature and a time TB required for the fire extinguishing process of the burner. The DPF regeneration control device according to claim 1.
TE = (Q−Q0) / D1 · ΔT + TR + TB (2) When the fire extinguishing process of the burner is started, the arithmetic unit is based on the following formula (3) consisting of an elapsed time TP from the start time of the fire extinguishing process to the present and a time TB required for the fire extinguishing process of the burner: The DPF regeneration control apparatus according to claim 1, wherein a remaining time TE until the completion of regeneration of the DPF is calculated.
TE = TB-TP (3)

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