TW202012769A - Exhaust-gas treatment apparatus - Google Patents

Abstract

This exhaust-gas treatment apparatus is provided with: a filter that collects particulate matter included in an exhaust gas flowing through the exhaust passage of an engine which is mounted on a vehicle; a temperature raising unit that raises the temperature of the exhaust gas entering the filter; and a control device that executes regeneration control for burning the particulate matter deposited on the filter by means of the exhaust gas raised in temperature by the temperature raising unit. The control unit executes control for reducing the outlet temperature of the exhaust passage when the outlet temperature exceeds a determination value through execution of the regeneration control during a car stop (S115-S118). Heating of surrounding objects caused by heat generated during filter regeneration can be suppressed without increasing manufacturing cost.

Description

Exhaust gas treatment device

The contents disclosed in this specification relate to an exhaust gas treatment device, and particularly to an exhaust gas having a filter for capturing particulate matter (PM: Particulate Matter) contained in exhaust gas flowing through an exhaust passage of an engine Processing device.

In the prior art, when there is an obstacle that is close to the front end of the exhaust pipe, it can automatically interrupt the filter used to remove PM (PM removal filter, also known as: diesel Carbon particle filter; DPF: Diesel Particulate Filter) forced regeneration control to prevent heating of obstacles (for example: refer to Japanese Patent Laid-Open No. 2005-264774 (hereinafter referred to as "Patent Document 1")). Patent Document 1 discloses that it is equipped with a distance sensor for detecting the distance between the front end of the exhaust pipe and an obstacle, and controls the output of the fuel used to oxidize the fuel according to the output value of the distance sensor The heat of reaction is supplied to the fuel added to the oxidation catalyst of the filter, thus interrupting the regeneration control of the filter. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2005-264774

[Technical problem to be solved by the invention]

However, the technology disclosed in Patent Document 1 requires a distance sensor, which will increase the manufacturing cost of the vehicle's exhaust treatment device. In addition, if there are many objects (for example, cars, people) moving near the front end of the exhaust pipe, they will be detected by the distance sensor, which often results in interruption of filter regeneration control.

The content disclosed in this specification was developed to solve the above-mentioned problems, and its purpose is to provide: an exhaust gas treatment device that does not increase the manufacturing cost and can reduce the heat used for filter regeneration control. Heating caused by surrounding objects. [Technical Solution to Solve the Problem]

The exhaust treatment device disclosed in this specification includes: a filter that captures particulate matter contained in the exhaust gas flowing through an exhaust passage of an engine mounted on a vehicle; The exhaust gas of the heater is heated; and a control device that performs regeneration control that burns the particulate matter accumulated in the filter by the exhaust gas heated by the temperature rising part. The control device executes control for reducing the outlet temperature when the outlet temperature of the exhaust passage exceeds the determination value due to the execution of regeneration control in the parking state.

As one of the suitable controls for reducing the outlet temperature, the control device is suppression regeneration control. For better control, the control device prohibits regeneration control.

As one of the suitable controls for lowering the outlet temperature, the control device is to reduce the rotation speed of the engine. For better control, the control device, after reducing the engine rotation speed, when the outlet temperature exceeds a judgment value higher than the judgment value, suppresses the regeneration control as an additional control for reducing the outlet temperature.

The determination value is preferably a value that decreases with the elapsed time from parking. More preferably, a temperature sensor for detecting the temperature of the exhaust gas is provided between the filter in the exhaust gas channel and the outlet of the exhaust gas channel. The control device estimates the outlet temperature from the temperature detected by the temperature sensor.

The temperature increasing section includes: a fuel addition device for adding fuel to the exhaust passage provided in the exhaust passage upstream of the filter; and a fuel addition device provided in the exhaust passage upstream of the filter and relatively The fuel addition device is further downstream, and is preferably an oxidation catalyst that uses fuel added by the fuel addition device to heat the exhaust gas.

The control device executes regeneration control when the accumulation amount of the particulate matter captured by the filter is larger than the predetermined amount.

The control device compares the state of the vehicle before stopping to back up with the state of the vehicle moving forward, and then uses a lower determination value to determine whether the exit temperature exceeds the determination value. [Effect of invention]

According to the contents disclosed in this specification, even if there is no detection device such as a sensor for detecting the distance between the outlet of the exhaust passage and the objects located around it, the exhaust passage in the parking state can be made The temperature of the outlet does not become too high. As a result, it is possible to provide an exhaust gas treatment device which does not increase the manufacturing cost and can reduce the heating of the surrounding objects caused by the heat used for filter regeneration control.

Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the drawings. In the figure, the same component symbol is marked for the same part or an equal part, and its repeated description is omitted.

FIG. 1 is a schematic configuration diagram showing the engine 1 of this embodiment. In this embodiment, the engine 1 is exemplified by taking the common rail diesel engine as an example. However, the engine 1 may also be another form of diesel engine. The engine 1 is mounted on the vehicle 2 and is connected to a drive wheel (not shown) of the vehicle 2 via a device such as a gearbox (not shown) to transmit the output of the engine 1 to the drive wheel (not shown) ).

The engine 1 is provided with: an engine body 10, an air cleaner 20, an intercooler 26, an intake manifold 28, a diesel throttle valve 29, a supercharger 30, an exhaust manifold 50, an exhaust treatment device 56, an exhaust Gas recirculation device (hereinafter referred to as EGR (Exhaust Gas Recirculation) device) 60, control device 200, engine speed sensor 202, vehicle speed sensor 204, throttle opening sensor 205, water temperature sensor 206, air flow meter 208, fuel pump 210, fuel filter 212, and fuel tank 214.

The engine body 10 includes a plurality of cylinders 12, a common rail 14, and a plurality of fuel injection nozzles 16. Although the engine 1 of this embodiment is described using an in-line four-cylinder engine as an example, other types of cylinder arrangement (for example, a V-type arrangement or a horizontal-type arrangement) may be used.

The plurality of fuel injection nozzles 16 are respectively provided in the cylinders of the plurality of cylinders 12 and are fuel injection devices respectively connected to the common rail 14. The fuel stored in the fuel tank 214 is pressurized by the fuel pump 210 via the fuel filter 212 to a predetermined pressure before it is supplied to the common rail 14. The fuel supplied to the common rail 14 is injected from each of the plurality of fuel injection nozzles 16 at a predetermined timing. The plurality of fuel injection nozzles 16 perform the injection operation according to the control signals IJ1~IJ4 from the control device 200.

The air cleaner 20 is used to remove foreign substances in the air taken in from the outside by the engine 1. The air cleaner 20 is connected to one end of the first intake pipe 22.

The other end of the first intake pipe 22 is connected to the inlet of the compressor 32 of the supercharger 30. The outlet of the compressor 32 is connected to one end of the second suction pipe 24. The compressor 32 pressurizes the air from the first intake pipe 22 and supplies it to the second intake pipe 24. The detailed operation capacity of the compressor 32 will be described later.

The other end of the second suction pipe 24 is one end connected to the intercooler 26. The intercooler 26 is an air-cooled or water-cooled heat exchanger for cooling the air flowing through the second intake pipe 24.

The other end of the intercooler 26 is one end connected to the third suction pipe 27. The other end of the third suction pipe 27 is connected to the suction manifold 28. The intake manifold 28 is an intake port connected to each of the plurality of cylinders 12 of the engine body 10. The first suction pipe 22, the second suction pipe 24, the third suction pipe 27, the suction manifold 28, and the suction port constitute a "suction passage".

The diesel throttle valve 29 is provided upstream of the intake manifold 28. The diesel throttle valve 29 is manufactured using an electric actuator (not shown) so that its throttle opening can be adjusted. The opening degree of the diesel throttle valve 29 (hereinafter, also referred to as diesel throttle opening degree) is controlled by a control signal from the control device 200. In this embodiment, when the opening degree of the diesel throttle valve is 100%, it means that the diesel throttle valve 29 is in a fully closed state. In addition, in this embodiment, when the opening degree of the diesel throttle valve is 0%, it means that the diesel throttle valve 29 is in the fully opened state. The opening degree of the diesel throttle is set after the exhaust gas treatment device 56 is warmed up and the vehicle 2 is not in a decelerating state control (hereinafter, referred to as normal control), which is set appropriately according to the operating state of the engine 1 Opening.

The exhaust manifold 50 is connected to each exhaust port of the plurality of cylinders 12 of the engine body 10. The exhaust manifold 50 is connected to one end of the first exhaust pipe 52. The other end of the first exhaust pipe 52 is connected to the turbine 36 of the supercharger 30. Therefore, the exhaust gas discharged from the exhaust port of each cylinder is collected in the exhaust manifold 50 before being supplied to the turbine 36 via the first exhaust pipe 52.

The turbine 36 is connected to one end of the second exhaust pipe 54. The other end of the second exhaust pipe 54 is an inlet portion connected to the exhaust treatment device 56. The exhaust gas treatment device 56 includes: an oxidation catalyst (DOC: Diesel Oxidation Catalyst) 56a, a PM removal filter 56b, a fuel addition device 56c, a first exhaust temperature sensor 56d, and a selective reduction catalyst (SCR catalyst: Selective Catalytic Reduction) 56e, second exhaust temperature sensor 56f, ammonia slip catalyst (ASC: Ammonia Slip Catalyst) 56g, and third exhaust temperature sensor 56h.

The PM removal filter 56b is provided in the exhaust gas flow path (exhaust passage) on the downstream side of the oxidation catalyst 56a. The fuel addition device 56c is provided upstream of the oxidation catalyst 56a in the exhaust gas flow path. The first exhaust temperature sensor 56d is provided in the PM removal filter 56b. The SCR catalyst 56e is provided downstream of the PM removal filter 56b in the exhaust gas flow path. The second exhaust temperature sensor 56f is provided between the PM removal filter 56b and the SCR catalyst 56e. ASC56g is provided in the exhaust gas flow path on the downstream side of the SCR catalyst 56e. The third exhaust temperature sensor 56h is provided downstream of the ASC 56g in the exhaust flow path.

The PM removal filter 56b is for capturing particulate matter contained in the flowing exhaust gas (hereinafter, referred to as PM (Particulate Matter)). The PM removal filter 56b is formed of, for example, ceramic, stainless steel, or the like. The captured PM is accumulated in the PM removal filter 56b.

The oxidation catalyst 56a and the fuel addition device 56c function as a regeneration mechanism that burns and removes the PM accumulated in the PM removal filter 56b (that is, the PM removal filter 56b is regenerated). When the exhaust gas is flowing, the oxidation catalyst 56a will oxidize with nitrogen oxides (NO _x ) and carbon oxides (CO _x ) in the flowing exhaust gas, and if the exhaust gas contains a secondary fuel addition device 56c If the fuel is added, the fuel will be oxidized. The exhaust gas passing through the oxidation catalyst 56a is heated by the reaction heat generated by the oxidation of the fuel. By passing the high-temperature exhaust gas through the PM removal filter 56b, the temperature of the PM removal filter 56b is increased, and the PM accumulated in the PM removal filter 56b is oxidized and removed (burned off). In this way, the PM removal filter 56b can be regenerated. The regeneration control of the PM removal filter 56b is executed when it is judged that the accumulation amount of PM is larger than the predetermined amount. The method for judging the accumulation amount of PM can be judged by a conventional method.

The SCR catalyst 56e is, for example, a monolithic catalyst in which a large number of through holes (blanks) are formed in the flow direction of exhaust gas, and is formed of chrysotile. A plating layer of a catalyst is formed on the wall surface of the space, and thus contains, for example, a zeolite-based active component (catalyst). When the active ingredient is exposed to the reducing agent, and thus will be activated selectively NO _x in the exhaust gas be restored.

A urea water injection valve (not shown) is provided on the upstream side of the SCR catalyst 56e. The urea water injection valve injects urea water into the exhaust pipe as a reducing agent. The urea water injected from the urea water injection valve receives the heat energy of the exhaust gas and undergoes hydrolysis to generate ammonia. The ammonia generated selectively react with NO _x in the exhaust gas in the SCR catalyst 56e is generated in nitrogen and water.

ASC56g is a catalyst used to oxidize ammonia that escapes from the SCR catalyst to prevent ammonia from being discharged into the atmosphere.

The outlet of the exhaust treatment device 56 is connected to one end of the third exhaust pipe 58. The other end of the third exhaust pipe 58 is connected to a muffler or the like. Therefore, the exhaust gas discharged from the turbine 36 is discharged to the outside of the vehicle through the second exhaust pipe 54, the exhaust treatment device 56, the third exhaust pipe 58, the muffler, and the like. The "exhaust passage" is constituted by the exhaust port, the exhaust manifold 50, the first exhaust pipe 52, the turbine 36, the second exhaust pipe 54 and the third exhaust pipe 58.

The third intake pipe 27 and the exhaust manifold 50 are not connected via the engine body 10 but by the EGR device 60. The EGR device 60 includes an EGR valve 62, an EGR cooler 64, and an EGR passage 66. The EGR passage 66 is used to connect the third intake pipe 27 and the exhaust manifold 50. The EGR valve 62 and the EGR cooler 64 are provided in the middle of the EGR passage 66.

The EGR valve 62 adjusts the exhaust gas flowing back into the intake passage from the exhaust manifold 50 through the EGR passage 66 of the EGR device 60 in response to the control signal from the control device 200 (hereinafter, the exhaust gas flowing back into the intake passage Also known as EGR oil and gas) flow rate. The EGR cooler 64 is a water-cooled or air-cooled heat exchanger that cools, for example, EGR oil and gas flowing in the EGR passage 66. Manifold 50 via the EGR exhaust gas in the EGR apparatus 60 as oil returned to the suction side, whereby the combustion temperature can be lowered in the cylinder, but may reduce the amount of NO _x.

The supercharger 30 includes a compressor 32 and a turbine 36. The compressor 32 houses the compressor impeller 34, and the turbine 36 houses the turbine impeller 38. The compressor wheel 34 and the turbine wheel 38 are connected together by a connecting shaft 42, and both can rotate integrally. Therefore, the compressor wheel 34 is rotationally driven by the exhaust gas kinetic energy supplied to the exhaust gas of the turbine wheel 38.

The operation of the engine 1 is controlled by the control device 200. The control device 200 includes a CPU (Central Processing Unit) for performing various processes, a ROM (Read Only Memory) for storing programs and data, and a RAM (Random Access Memory) for storing processing results of the CPU, etc. Memory and other input ports and output ports for exchanging information with the outside (none of the above components are shown). The input port is connected to the above sensors (for example: the first exhaust temperature sensor 56d, the second exhaust temperature sensor 56f, the third exhaust temperature sensor 56h, the engine speed sensor 202, the vehicle speed sensor 204 , Throttle opening sensor 205, water temperature sensor 206, air flow meter 208, etc.). The output port is connected to the device that is the object of control (for example: a plurality of fuel injection nozzles 16, a fuel addition device 56c, a fuel pump 210, etc.).

The control device 200 controls various machines according to signals from each sensor and machine, correspondence tables and programs stored in the memory to maintain the engine 1 in a desired operating state. In addition, the various controls are not limited to the use of software for processing, but can also be processed using dedicated hardware (circuits). In addition, inside the control device 200 is provided a timer circuit (not shown) for measuring time.

The first exhaust temperature sensor 56d is used to detect the exhaust temperature (hereinafter, referred to as a first exhaust temperature) Tex1 inside the PM removal filter 56b. The first exhaust temperature sensor 56d sends a signal indicating the detected first exhaust temperature Tex1 to the control device 200.

The second exhaust temperature sensor 56f is used to detect the exhaust temperature (hereinafter referred to as the second exhaust temperature) Tex2 flowing into the SCR catalyst 56e. The second exhaust temperature sensor 56f sends a signal indicating the detected second exhaust temperature Tex2 to the control device 200.

The third exhaust temperature sensor 56h is used to detect the exhaust temperature (hereinafter referred to as the third exhaust temperature) Tex3 flowing from the ASC. The third exhaust temperature sensor 56h sends a signal indicating the detected third exhaust temperature Tex3 to the control device 200.

The engine rotation speed sensor 202 detects the rotation speed of the crankshaft of the engine 1 as the engine rotation speed NE. The engine speed sensor 202 sends a signal indicating the detected engine rotation speed NE to the control device 200.

The vehicle speed sensor 204 detects the speed of the vehicle 2 (hereinafter, referred to as vehicle speed) V. The vehicle speed sensor 204 sends a signal indicating the detected vehicle speed V to the control device 200.

The accelerator opening sensor 205 detects a ratio (hereinafter, referred to as an accelerator opening) Acc of a current stepping amount to an upper limit value of a stepping amount of an accelerator pedal (not shown). The accelerator opening sensor 205 sends a signal indicating the detected accelerator opening Acc to the control device 200.

The water temperature sensor 206 detects the temperature (water temperature) Tw of the cooling water flowing in the cooling water passage provided in the engine body 10. The water temperature sensor 206 sends a signal indicating the detected water temperature Tw to the control device 200.

The air flow meter 208 detects the flow rate (amount of intake air) Qin of fresh air introduced into the first intake pipe 22. The air flow meter 208 sends a signal indicating the detected intake air amount Qin to the control device 200.

The fuel tank 214 is used to store fuel to be supplied to the plurality of fuel injection nozzles 16 and the fuel addition device 56c. The fuel pump 210 operates in response to a control signal from the control device 200 to pressurize the fuel stored in the fuel tank 214 to the common rail 14 or supply it to the fuel addition device 56c. A fuel filter 212 is provided in the fuel passage between the fuel pump 210 and the fuel tank 214. The fuel filter 212 is used to catch foreign substances contained in the flowing fuel.

[Control of exhaust to prevent high temperature] When the engine 1 having the above-described constituent elements is to perform the regeneration control of the PM removal filter 56b in the parking state of the vehicle 2, the exhaust gas from the exhaust port will heat the surrounding objects.

Therefore, the control device 200 of this embodiment executes the control for reducing the outlet temperature when the outlet temperature of the exhaust passage exceeds the determination value due to the execution of regeneration control in the parking state of the vehicle 2.

In this way, it can be controlled so that the temperature of the outlet of the exhaust passage does not become too high in the parking state. As a result, it is possible to reduce the heating of the surrounding objects by the heat used for the regeneration control of the PM removal filter 56b.

(First embodiment) FIG. 2 is a flowchart showing the flow of the high-temperature exhaust gas prevention processing of the first embodiment. This high-temperature exhaust prevention process is to call this sub-program from the main processing program every predetermined control cycle and hand it over to the control device 200 for execution. As shown in FIG. 2, the control device 200 is when the vehicle speed V indicated by the signal from the vehicle speed sensor 204 is 0 and the engine rotation speed NE displayed by the signal from the engine speed sensor 202 is not 0. It is judged whether the vehicle 2 is in the parking state (step (hereinafter, abbreviated as "S" 101)).

When it is determined that the vehicle 2 is in the parking state (YES in S101), the control device 200 determines whether the regeneration control of the PM removal filter is being executed (S102). If the regeneration control is being executed, the control device 200 performs control to add fuel from the fuel addition device 56c of the exhaust treatment device 56. Therefore, if the control device 200 is controlled to add fuel using the fuel addition device 56c, it is determined that regeneration control is being performed.

When it is determined that the regeneration control is being executed (YES in S102), the control device 200 calculates the exhaust passage based on the third exhaust temperature Tex3 displayed by the signal from the third exhaust temperature sensor 56h The temperature of the outlet is the estimated value of the T/P (Tail Pipe) gas temperature (S103).

As long as the estimated value of the T/P gas temperature is data calculated using the third exhaust gas temperature Tex3, it can be calculated by any conventional method. For example, the estimated value of the T/P gas temperature can be calculated by subtracting the temperature loss from the third exhaust temperature sensor 56h to the outlet of the exhaust passage from the third exhaust temperature Tex3. The temperature loss is calculated by subtracting the temperature of the exhaust pipe wall from the third exhaust temperature Tex3, and then multiplying the temperature by a predetermined coefficient defined by the third exhaust temperature Tex3 and the amount of intake air. The given coefficient is the value after subtracting the temperature reaching ratio from 1. The reached temperature ratio is selected using a two-dimensional correspondence table. In this two-dimensional correspondence table, the reached temperature ratio corresponding to the combined numerical value of the third exhaust temperature Tex3 and the amount of intake air is set in advance.

The calculation method of the exhaust pipe wall temperature is to first add the heated temperature of the exhaust pipe due to heating to the exhaust pipe wall temperature of the previous control cycle, and then subtract the heat radiation from the exhaust pipe to the atmosphere. The reduced heat dissipation temperature is therefore calculated. The method of calculating the heated temperature is to first multiply the intake air volume and the control period by the temperature loss of the previous control period, and then divide by the weight of the exhaust system through which the exhaust gas passes and the specific heat of the exhaust system, thus calculated . The calculation method of the heat release temperature is calculated by first multiplying the control period by the heat dissipation energy, and then dividing by the weight of the exhaust system and the specific heat of the exhaust system. The calculation method of the heat dissipation energy is calculated by adding the vehicle speed wind heat dissipation energy to the basic value of the heat dissipation energy. The basic value of heat dissipation energy is selected using a two-dimensional correspondence table. In this two-dimensional correspondence table, the basic value of the heat dissipation energy corresponding to the combined value of the temperature difference and the intake air amount after subtracting the outside air temperature from the exhaust pipe wall temperature of the previous control cycle is preset. The vehicle speed and wind heat dissipation energy is selected using a one-dimensional correspondence table corresponding to the vehicle speed and the vehicle speed and wind heat dissipation energy (when the vehicle speed is 0, the vehicle speed and wind heat dissipation energy is 0).

In addition, the signal from the third exhaust temperature sensor 56h varies slightly. Therefore, it is preferable to use the third exhaust temperature Tex3 after smoothing (leveling).

Alternatively, the T/P gas temperature estimated value may be selected using a correspondence table in which T/P gas temperature estimated values corresponding to plural combinations of each of the above-mentioned parameters are set in advance.

Next, the control device 200 determines whether the estimated value of the T/P gas temperature calculated at the present time is greater than or equal to the value on the curve indicating the first determination value (S104).

FIG. 3 is an explanatory diagram for explaining the method of determining the estimated T/P gas temperature according to the first embodiment. As shown in FIG. 3, the temperature shown as the first determination value on the curve representing the first determination value decreases as the elapsed time after the vehicle 2 stops at the idle state increases, and decreases to a certain value In the future, even if the elapsed time is still increasing, the temperature will still maintain a certain value.

When the vehicle 2 is stopped in the idling state, if regeneration control of the PM removal filter is executed, the estimated T/P gas temperature value will be shifted by a value close to the first determination value. In the example of FIG. 3, when the elapsed time reaches the elapsed time indicated by the broken line, the estimated T/P gas temperature will reach the first judgment value.

Returning to FIG. 2 to explain, if it is determined that the estimated value of the T/P gas temperature is greater than or equal to the value on the curve indicating the first determination value (YES in S104), the control device 200 prohibits the execution of PM removal filtering The regeneration control of the device 56b (S105). In this way, if the regeneration control is originally being executed, the regeneration control will be forcibly terminated. As a result, as shown in FIG. 3, the estimated value of the T/P gas temperature decreases and becomes lower than the first judgment value.

If it is judged that it is not in the parking state (NO in S101), if it is judged that the regeneration control is not being executed (NO in S102), and if it is judged that the estimated value of the T/P gas temperature is not If it is greater than or equal to the numerical value on the curve indicating the first determination value (NO in S104), after S105, the control device 200 will determine whether the vehicle 2 has started to travel? Or has the operation been started manually? PM removal filter 56b regeneration control (S106).

When it is determined that the driving has started or the regeneration control has been started (YES in S106), the control device 200 cancels the prohibition of the execution of the regeneration control of the PM removal filter 56b, in other words, allows the execution of the PM removal filter 56b The regeneration control (S107). In this way, as long as the conditions for executing the regeneration control are satisfied, the execution of the regeneration control will start again.

If it is determined that the driving has not started and the regeneration control operation has not been started (NO in S106), after S107, the control device 200 will restore the processing to be executed to be called out to perform such processing The processing in the original main processing program of the secondary program of.

(Second embodiment) In the first embodiment, as the control for preventing high-temperature exhaust gas, a control for prohibiting the regeneration control of the PM removal filter 56b based on the first determination value is executed. In the second embodiment, as the control for preventing high-temperature exhaust gas, in addition to the control of the first embodiment, the control of reducing the rotation speed of the idle state of the engine 1 based on the second determination value is executed.

FIG. 4 is a flowchart showing the flow of the high-temperature exhaust gas prevention processing of the second embodiment. This high-temperature exhaust prevention process is to call this sub-program from the main processing program every predetermined control cycle and hand it over to the control device 200 for execution. As shown in FIG. 4, the processing of S111 to S113 is the same as the processing of S101 to S103 in FIG. 2 respectively, so the repeated description thereof is omitted here.

After S113, the control device 200 determines whether or not the control to reduce the rotation speed of the engine 1 in the idling state is being executed (S114). If it is determined that the control for reducing the idling speed is not being executed (NO in S114), the control device 200 determines whether the estimated value of the T/P gas temperature calculated at the present time is greater than or equal to the value indicating the second determination value The value on the curve (S115).

FIG. 5 is an explanatory diagram for explaining the method for determining the estimated value of the T/P gas temperature in the second embodiment. As shown in FIG. 5, the temperature shown as the second determination value displayed on the curve indicating the second determination value will be the same as the first determination value as the elapsed time after the vehicle 2 stops at the idle state increases Decrease, after the decrease reaches a certain value, even if the elapsed time increases, it still maintains a certain value of temperature. The decrease in the curve indicating the second judgment value is several tens of degrees Celsius lower than the decrease in the curve indicating the first judgment value.

When the vehicle 2 is stopped at the idling state, if the regeneration control of the PM removal filter is executed, the estimated T/P gas temperature will shift to a value close to the second judgment value and the first judgment value. In the example of FIG. 5, when the elapsed time of the first stage indicated by the dotted line is reached, the second determination value is reached. In addition, when the elapsed time of the second stage indicated by the dotted line is reached, the first judgment value is reached.

Returning to FIG. 4 to explain, when it is determined that the estimated value of the T/P gas temperature is greater than or equal to the value on the curve indicating the second determination value (YES in S115), the control device 200 starts to perform the idling reduction state The control of the engine rotation speed (S116). In this way, the heat energy of the exhaust gas per unit time can be reduced, and therefore it is expected that the estimated value of the T/P gas temperature will decrease. In addition, the difference from the first embodiment is that the rotation speed of the engine in the idling state is first reduced. Therefore, at least the execution of the regeneration control of the PM removal filter 56b can be prohibited.

When it is determined that the control for reducing the idling speed is being executed (YES in S114), the process of S117 is executed. The processes of S117 and S118 are the same as the processes of S104 and S105 in the second figure, respectively, and therefore their repeated explanations are omitted.

When it is judged that it is not in the parking state (NO in S111), when it is judged that it is not in the case of performing regeneration control (NO in S112), and the estimated value of the T/P gas temperature is not greater than or equal to In the case of the numerical value on the curve indicating the second judgment value (NO in S115), after S116, the estimated value of the T/P gas temperature is not greater than or equal to the numerical value on the curve indicating the first judgment value (NO in S117) In this case, after S118, the control device 200 executes the process of S119. The processing of S119 and S120 is the same as the processing of S106 and S107 in the second figure, respectively, and therefore the repeated description thereof is omitted.

[Variation] (1) In the foregoing embodiment, as shown in S103 in FIG. 2 and S113 in FIG. 4, it is calculated based on the exhaust temperature flowing from ASC56g, that is, the third exhaust temperature Tex3 Estimated value of T/P gas temperature. However, it is not limited to this, and the estimated value of the T/P gas temperature may be calculated based on signals from other temperature sensors. For example, the estimated value of the T/P gas temperature may be calculated based on the exhaust temperature inside the PM removal filter 56b, which is the first exhaust temperature Tex1, or may be calculated based on the exhaust gas flowing into the SCR catalyst 56e The temperature is calculated as the second exhaust temperature Tex2.

However, it is preferable to calculate the T/P gas temperature based on the temperature indicated by the signal from the temperature sensor located at the end of the exhaust passage closest to the outlet of the exhaust passage. Therefore, in the aforementioned embodiment, the T/P gas temperature is preferably calculated based on the third exhaust gas temperature Tex3.

In addition, a temperature sensor can also be provided in other parts of the exhaust passage, and the estimated value of the T/P gas temperature can be calculated based on the signal from the temperature sensor. In addition, a temperature sensor can also be provided at the outlet of the exhaust channel, and the temperature of the T/P gas itself can be calculated based on the signal from the temperature sensor.

(2) In the aforementioned embodiment, as shown in FIGS. 3 and 5, a correspondence table is used to determine the estimated T/P gas temperature value. However, it is not limited to this, and the estimated T/P gas temperature may be determined using different correspondence tables before the vehicle 2 stops, when the vehicle 2 travels backward, and when the vehicle 2 travels forward. Generally, it is considered that the situation where the vehicle 2 stops before moving forward is compared with the situation where the vehicle 2 stops after moving backward, and the distance between the exit of the exhaust passage and the objects located around the exhaust port is compared in the former case. long. Therefore, if you stop before going forward, you can use the judgment value of less strict conditions than the first judgment value and the second judgment value shown in Figure 3 and Figure 5 (that is, compared to the first The judgment value and the second judgment value are higher judgment values). In this way, the regeneration control of the PM removal filter 56b can be continued.

(3) In the aforementioned embodiment, as shown in S105 in FIG. 2 and S118 in FIG. 4, execution of the regeneration control of the PM removal filter 56b is prohibited. However, it is not limited to this. As long as the temperature of the T/P gas decreases, the regeneration control of the PM removal filter 56b may be reduced. For example, the temperature at which regeneration control is performed can be changed from a higher temperature to the minimum temperature at which regeneration control can be performed.

(4) In the aforementioned embodiment, when the estimated value of the T/P gas temperature is greater than or equal to the determination value, the execution of the regeneration control is reduced by prohibiting the execution of the regeneration control. However, it is not limited to this, and the regeneration control may be reduced in stages in accordance with the difference between the estimated value of the T/P gas temperature and the determination value. For example, the difference between the estimated value of the T/P gas temperature and the judgment value can be compared with the case where the difference is large, and the temperature at which the former performs regeneration control can be lowered.

(5) In the aforementioned embodiment, the exhaust gas treatment device 56 is controlled by the control device 200. This method can be regarded as that the control device 200 includes the control device of the exhaust gas treatment device 56. However, a control device dedicated to the exhaust gas treatment device 56 different from the control device 200 may be provided.

(6) The foregoing embodiment can be regarded as an explanation of the exhaust gas treatment device 56. Furthermore, it can be regarded as the disclosure of the control device 200 of the exhaust gas treatment device 56 or the disclosure of the control method of the exhaust gas treatment device 56. It can also be regarded as the disclosure of the engine 1 or the vehicle 2.

[effect] (1) According to the description given in FIG. 1, it can be seen that the exhaust gas treatment device 56 is equipped with: PM removal for capturing particulate matter contained in the exhaust gas flowing in the exhaust passage of the engine 1 mounted on the vehicle 2 A filter 56b; a temperature rising part for heating the exhaust gas flowing into the PM removing filter 56b; a particulate matter accumulated in the PM removing filter 56b is executed by using the exhaust gas heated by the temperature rising part Control device 200 for combustion regeneration control. As shown in S101 to S105 in FIG. 2 and S111 to S118 in FIG. 4, when the regeneration state is executed in the parking state, the outlet temperature of the exhaust passage exceeds the first judgment value or the second When the determination value is reached, the control device 200 executes control for reducing the temperature of the T/P gas (for example, prohibiting the execution of the regeneration control of the PM removal filter 56b and reducing the reduction of the rotation speed when the engine 1 is idling).

In this way, even if there is no sensor device such as a sensor for detecting the distance between the outlet of the exhaust passage and the objects located around it, the vehicle 2 can be prevented from causing the exhaust passage when it is parked The temperature of the outlet becomes too high. As a result, without increasing the manufacturing cost, it is possible to reduce the heating of the surrounding objects by the heat used for the regeneration control of the PM removal filter 56b.

(2) As shown in S105 in FIG. 2 and S118 in FIG. 4, the control method performed by the control device 200 to reduce the temperature of the T/P gas is to reduce the execution of the regeneration control of the PM removal filter 56b. In this way, the temperature of the outlet of the exhaust passage can be reduced.

(3) As shown in S105 in FIG. 2 and S118 in FIG. 4, the control device 200 reduces the regeneration control of the PM removal filter 56b by prohibiting the execution of the regeneration control of the PM removal filter 56b. In this way, the temperature of the outlet of the exhaust passage can be greatly reduced.

(4) As indicated by S116 in FIG. 4, the control method of the control device 200 for reducing the outlet temperature is to reduce the rotation speed of the engine 1. In this way, the regeneration control of the PM removal filter 56b can be continued as much as possible.

(5) As shown in S117 and S118 in FIG. 4, when the rotation speed of the engine 1 is lowered and the outlet temperature exceeds the first judgment value higher than the second judgment value, the control device 200 reduces the PM removal filter The regeneration control of 56b is used as an additional control method to reduce the outlet temperature. In this way, the regeneration control of the PM removal filter 56b can be continuously executed as much as possible, and the heating of the surrounding objects can be reduced.

(6) As shown in FIGS. 3 and 5, the first judgment value and the second judgment value are numerical values that become smaller as the elapsed time from when the vehicle 2 stops. The longer the elapsed time from parking, the longer the heating time for surrounding objects. In this way, by reducing the judgment value in accordance with the elapsed time from the stop, it is possible to achieve an appropriate judgment corresponding to the heating time.

(7) As shown in Fig. 1, it is further provided with a third exhaust temperature sensor for detecting the temperature of the exhaust gas between the PM removal filter 56b provided in the exhaust gas channel and the outlet of the exhaust gas channel 56h. The control device 200 can estimate the outlet temperature from the third exhaust temperature Tex3 detected by the third exhaust temperature sensor 56h. In this way, the outlet temperature can be estimated appropriately.

(8) As shown in FIG. 1, the temperature rising section includes: a fuel addition device 56c provided in the exhaust passage upstream of the PM removal filter 56b for adding fuel to the exhaust passage; An oxidation catalyst 56a that raises the temperature of the exhaust gas using the fuel added by the fuel addition device 56c in the air passage is upstream of the PM removal filter 56b and downstream of the fuel addition device 56c. In this way, the regeneration control of the PM removal filter 56b can be executed more efficiently.

(9) As already explained in FIG. 1, when the accumulation amount of the particulate matter captured by the PM removal filter 56b is larger than a predetermined amount, the control device 200 executes the regeneration control of the PM removal filter 56b. In this way, the regeneration control of the PM removal filter 56b can be appropriately executed.

(10) It has been explained in the modified example that the control device 200 compares the situation where the vehicle 2 is traveling backwards and traveling forwards before stopping, and uses a lower judgment value to determine whether the exit temperature has exceeded Judgment value. Generally, it is considered that the situation where the vehicle 2 stops before moving forward is compared with the situation where the vehicle 2 stops after moving backward, and the distance between the exit of the exhaust passage and the objects located around the exhaust port is compared in the former case. long. Therefore, in the case of stopping after driving backwards, a judgment value with stricter conditions than the first judgment value and the second judgment value shown in FIGS. 3 and 5 (that is, compared with the first judgment Value and the second judgment value are lower judgment values). In this way, the regeneration control of the PM removal filter 56b can be continued.

The embodiments disclosed this time are also expected to be implemented after appropriately combining these embodiments. In addition, all the configuration methods in the embodiments disclosed this time are only examples, and are not intended to be limited to such configuration methods. The scope disclosed in this description not only includes the description of the above-mentioned embodiments, but also covers the scope disclosed in the patent application, as well as the meaning equivalent to the scope of the patent application and all changes within the scope of the patent application. Included.

1: engine 2: vehicle 10: Engine body 12: cylinder 14: Common Rail 16: Injector 20: Air filter 22: 1st suction tube 24: 2nd suction tube 26: Intercooler 27: 3rd suction tube 28: Suction manifold 29: Diesel throttle valve 30: Turbocharger 32: Compressor 34: Compressor impeller 36: Turbine 38: Turbine impeller 42: connecting shaft 50: exhaust manifold 52: The first exhaust pipe 54: 2nd exhaust pipe 56: Exhaust gas treatment device 56a: Oxidation catalyst 56b: PM removal filter 56c: Fuel adding device 56d: 1st exhaust temperature sensor 56e: SCR catalyst 56f: 2nd exhaust temperature sensor 56h: 3rd exhaust temperature sensor 58: 3rd exhaust pipe 60: EGR device 62: EGR valve 64: EGR cooler 66: EGR channel 200: control device 202: Engine speed sensor 204: Speed sensor 205: throttle opening sensor 206: Water temperature sensor 208: Air flow meter 210: Fuel pump 212: Fuel filter 214: Fuel tank

Fig. 1 is a schematic configuration diagram showing the engine of this embodiment. FIG. 2 is a flowchart showing the flow of the high-temperature exhaust gas prevention processing of the first embodiment. FIG. 3 is an explanatory diagram for explaining a method of determining the estimated T/P gas temperature in the first embodiment. FIG. 4 is a flowchart showing the flow of the high-temperature exhaust gas prevention processing of the second embodiment. FIG. 5 is an explanatory diagram for explaining a method of determining the estimated value of the T/P gas temperature in the second embodiment.

Claims (10)

An exhaust gas treatment device, which is provided with: A filter that captures particulate matter contained in the exhaust gas flowing through the exhaust passage of the engine mounted on the vehicle; A temperature-increasing part, which heats the exhaust gas flowing into the filter; and The control device executes regeneration control to burn the particulate matter accumulated in the filter by the exhaust gas heated by the temperature increasing part, The control device executes control for reducing the outlet temperature when the outlet temperature of the exhaust passage exceeds the determination value due to the execution of the regeneration control in the parking state. The exhaust gas treatment device according to item 1 of the patent application range, wherein the control device suppresses the regeneration control as a control for reducing the outlet temperature. The exhaust gas treatment device according to Item 2 of the patent application range, wherein the control device suppresses the inhibition by prohibiting the regeneration control. The exhaust gas treatment device according to item 1 of the patent application range, wherein the control device reduces the rotation speed of the engine as a control for reducing the outlet temperature. The exhaust gas treatment device according to item 4 of the patent application range, wherein after the control device reduces the rotation speed of the engine, when the outlet temperature exceeds a determination value higher than the determination value, the regeneration is suppressed The control serves as an additional control for reducing the aforementioned outlet temperature. The exhaust gas treatment device according to item 1 of the scope of the patent application, wherein the determination value is a value that decreases as the elapsed time from parking. The exhaust gas treatment device according to item 1 of the patent application scope, further comprising: a temperature sensor provided between the filter in the exhaust passage and the outlet of the exhaust passage for detecting The temperature of the exhaust, The control device estimates the outlet temperature from the temperature detected by the temperature sensor. The exhaust gas treatment device according to item 1 of the patent application scope, wherein the temperature increasing section includes: A fuel addition device, which is provided in the exhaust passage more upstream than the filter, for adding fuel to the exhaust passage; and The oxidation catalyst is provided in the exhaust passage upstream of the filter and downstream of the fuel addition device, and uses the fuel added by the fuel addition device to heat the exhaust gas. The exhaust gas treatment device according to item 1 of the patent application range, wherein the control device executes the regeneration control when the accumulation amount of the particulate matter captured by the filter is greater than a predetermined amount. The exhaust gas treatment device according to item 1 of the patent application scope, wherein the control device compares the condition of the vehicle before parking to the backward state with the state of the vehicle forward, and uses a lower determination value to determine the outlet temperature Whether the aforementioned judgment value is exceeded.

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