JP2019183796A - Control device for internal combustion engine - Google Patents

Abstract

To safely perform regeneration processing of a filter for collecting particulate matters.SOLUTION: A control device for an internal combustion engine includes: a filer provided in an exhaust passage of an internal combustion engine mounted to a vehicle and collecting particulate matters included in exhaust gas; a regeneration section for when determining that predetermined amount or more of particulate matters are accumulated in the filter, regenerating the filter by burning and incinerating the particulate matters accumulated in the filter; a discrimination section for discriminating the state of a road surface on which the vehicle travels; and a prohibition section for prohibiting regeneration of the filter by the regeneration section on the basis of the discriminated state of the road surface.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control device for an internal combustion engine.

  In order to prevent particulate matter containing carbon as a main component (hereinafter referred to as PM (Particulate Matter)) contained in the exhaust gas of the diesel engine from being discharged into the atmosphere, the exhaust passage of the diesel engine, for example, , DPF (Diesel Particulate Filter) is arranged to collect PM.

  When PM is collected by the DPF, the filter is clogged when the amount of accumulated PM increases. Therefore, when the trapped amount (deposition amount) of PM trapped in the DPF reaches a predetermined amount, the temperature of the exhaust gas flowing into the DPF is raised, and the filter regeneration for burning and incinerating the PM deposited in the DPF Processing is in progress.

  When the filter regeneration process is executed, the temperature of the exhaust pipe including the DPF becomes high. Therefore, it is desirable to perform the filter regeneration process in a state where the surrounding safety is ensured. Therefore, even when the amount of PM collected reaches a predetermined amount, if a predetermined condition is satisfied, the filter regeneration process is suspended or prohibited. For example, in Patent Document 1, when no worker is detected in the vehicle, the filter regeneration process is not performed.

JP 2012-92756 A

  However, according to the conventional technology, there is a possibility that the surrounding safety is insufficient when the DPF regeneration process is executed.

  Therefore, an object of the control device for an internal combustion engine disclosed in the present specification is to ensure that the regeneration process of the filter that collects the particulate matter is performed safely.

  In order to solve this problem, an internal combustion engine control device disclosed in the present specification is provided in an exhaust passage of an internal combustion engine mounted on a vehicle, and a filter that collects particulate matter contained in exhaust gas. When it is determined that a predetermined amount or more of particulate matter has been deposited on the filter, a regeneration unit that regenerates the filter by burning and incinerating the particulate matter deposited on the filter, and a state of a road surface on which the vehicle travels are determined. A discriminating unit for discriminating; and a prohibiting unit for prohibiting regeneration of the filter by the reproducing unit based on the determined state of the road surface.

  According to the control device for an internal combustion engine disclosed in the present specification, it is possible to safely perform the regeneration process of the filter that collects the particulate matter.

FIG. 1 is a schematic diagram illustrating a configuration of an engine system to which a control device for an internal combustion engine according to an embodiment is applied. FIG. 2 is a flowchart illustrating an example of a filter regeneration prohibiting process executed by the ECU.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, in the drawings, the dimensions, ratios, and the like of each part may not be shown so as to completely match the actual ones. In some cases, details are omitted in some drawings.

  First, an engine system to which a control device for an internal combustion engine according to an embodiment is applied will be described with reference to FIG. FIG. 1 is a schematic diagram showing a configuration of an engine system 500 to which an internal combustion engine control apparatus according to an embodiment is applied.

  The engine system 500 includes an engine 10 as an internal combustion engine including a diesel engine. The engine 10 is a four-cylinder engine, for example. The engine 10 is provided with an injector 35 for injecting fuel in each cylinder. The injector 35 supplies an appropriate amount of fuel to each cylinder at an appropriate timing based on a drive signal from an ECU (Electronic Control Unit) 50 described later. The engine 10 is provided with a crank angle sensor 34 that outputs a detection signal corresponding to the rotation of the crankshaft. The engine 10 is also provided with a water temperature sensor for detecting the engine water temperature (cooling water temperature).

  An intake passage 11 and an exhaust passage 12 are connected to the combustion chamber of the engine 10. An air flow meter 31 for detecting the intake air amount and a throttle valve (not shown) for adjusting the intake air amount are arranged in the intake passage 11. The air flow meter 31 outputs a detection signal corresponding to the flow rate of air taken in by the engine 10 to the ECU 50.

  The exhaust passage 12 of the engine 10 is provided with a fuel addition valve 21, exhaust gas temperature sensors 61A to 61C, an oxidation catalyst 41, a particulate collection filter 42, and the like.

  The fuel addition valve 21 is provided on the upstream side of the oxidation catalyst 41, and temporarily injects fuel when assisting the activation of the oxidation catalyst 41 based on a drive signal from the ECU 50. The fuel addition valve 21 may be omitted, and fuel injection (so-called post-injection) for supporting the activation of the oxidation catalyst 41 may be performed from the cylinder injector 35 at the timing of the exhaust process.

  The oxidation catalyst 41 is a catalyst that renders hydrocarbon (HC) and carbon monoxide (CO) harmless. The particulate collection filter 42 is a so-called DPF that collects particulate matter in the exhaust gas.

  The exhaust gas temperature sensors 61 </ b> A to 61 </ b> C are temperature sensors that detect the temperature of the exhaust gas, and output detection signals to the ECU 50. The exhaust gas temperature sensors 61A, 61B, 61C respectively include an exhaust gas inlet of the oxidation catalyst 41, an exhaust gas outlet of the oxidation catalyst 41, an exhaust gas inlet of the particulate collection filter 42, and a particulate collection filter 42. At the outlet of the exhaust gas. Note that the number and positions of the exhaust gas temperature sensors are not limited to the numbers and positions shown in the example of FIG.

  The engine system 500 includes an ECU 50. The ECU 50 includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and a storage device. The ECU 50 executes a filter regeneration prohibiting process to be described later by executing a program stored in the ROM or the storage device. The ECU 50 is an example of a reproduction unit, a determination unit, and a prohibition unit.

  Various actuators such as the injector 35, the throttle valve, and the fuel addition valve 21 are connected to the output side of the ECU 50.

  On the input side of the ECU 50, in addition to the air flow meter 31, the crank angle sensor 34, and the exhaust gas temperature sensors 61 </ b> A to 61 </ b> C described above, an outside air temperature sensor 37 that detects the temperature of the outside air around the vehicle, and the traveling speed of the vehicle are detected. A speed detection sensor 38 and an accelerator opening sensor 33 for detecting the amount of depression of the accelerator pedal by the driver are connected. The ECU 50 regenerates the particulate collection filter 42 by burning and burning the particulate matter deposited on the particulate collection filter 42 based on various information and signals regarding the operating state and operating conditions of the engine input from each sensor. A filter regeneration process and a filter regeneration prohibiting process that prohibits the filter regeneration process are executed.

  FIG. 2 is a flowchart illustrating an example of the filter regeneration prohibiting process executed by the ECU 50. The process of FIG. 2 is repeatedly executed while the engine 10 is operating.

  The ECU 50 first determines whether or not an execution condition for filter regeneration processing for regenerating the particulate collection filter 42 is satisfied (step S11). For example, if it is determined that a predetermined amount or more of PM has accumulated on the particulate collection filter 42, the ECU 50 determines that an execution condition for the regeneration processing of the particulate collection filter 42 is satisfied. Whether or not a predetermined amount or more of PM has accumulated on the particulate collection filter 42 can be determined, for example, by the difference in pressure before and after the particulate collection filter 42.

  If the filter regeneration process execution condition is not satisfied (step S11 / NO), the ECU 50 ends the process of FIG.

  When the execution condition for the filter regeneration process is satisfied (step S11 / YES), the ECU 50 estimates the vehicle state (step S12). More specifically, the ECU 50 estimates the engine load and the vehicle speed. For example, the ECU 50 estimates the engine load from the accelerator opening, or from the engine speed and the fuel injection amount. Further, the ECU 50 estimates the vehicle speed from the engine speed calculated based on, for example, an input value from the speed detection sensor 38 or an input value from the crank angle sensor 34. Alternatively, the ECU 50 may estimate the vehicle speed based on the current shift range.

  Subsequently, the ECU 50 determines whether or not the estimated vehicle state satisfies a predetermined condition (step S13). When the vehicle state satisfies a predetermined condition (step S13 / YES), the filter regeneration process is prohibited (step S21). ). More specifically, the ECU 50 prohibits the filter regeneration process when the engine load is equal to or greater than a predetermined value. When the engine load exceeds a predetermined value, the temperature of the exhaust gas exceeds the lower limit of the exothermic reaction temperature of the combustible material (for example, the lower exothermic reaction temperature of plant fibers: 276 ° C.). For this reason, if there is a combustible material such as hay in the vicinity of the exhaust pipe, the combustible material may ignite and it is difficult to perform the filter regeneration process safely. Further, the ECU 50 prohibits the filter regeneration process when the vehicle is at a low speed (for example, 10 km / h or less). At low vehicle speeds, it takes longer for the exhaust pipe and the combustible material (for example, hay) around the exhaust pipe to come into contact with each other. This increases the possibility of the combustible material being ignited, making it difficult to perform the filter regeneration process safely. Because.

  On the other hand, when the vehicle state does not satisfy the predetermined condition (step S13 / NO), the ECU 50 estimates the road surface state (step S14). More specifically, the ECU 50 estimates the unevenness level of the road surface. Since the damping force of the damper is controlled to be somewhat low when traveling on an uneven road surface, the ECU 50 estimates the unevenness level of the road surface based on a control signal input to the suspension to control the damper. can do. Note that the ECU 50 may estimate the state of the road surface based on the detection value of the vehicle height sensor that detects the vehicle height value at the mounting position of each wheel.

  Subsequently, the ECU 50 determines whether or not the road surface condition satisfies a predetermined condition (step S15), and when the road surface condition satisfies the predetermined condition (step S15 / YES), the filter regeneration process is prohibited (step S21). ). More specifically, the ECU 50 prohibits the filter regeneration process when the road surface unevenness level is equal to or higher than a predetermined value (when the road surface is uneven). When the road surface is uneven, the load clearance between the exhaust pipe and the road surface is shortened. At this time, if there is a combustible material such as hay in the periphery of the exhaust pipe, the exhaust pipe and the combustible material come into contact with each other, and the combustible material may ignite.

  On the other hand, when the road surface condition does not satisfy the predetermined condition (step S15 / NO), the ECU 50 detects the exhaust gas temperature detected based on the detection signals of the exhaust gas temperature sensors 61A to 61C and the detection signal of the outside air temperature sensor 37. The temperature of the exhaust pipe (the temperature of the surface of the exhaust pipe exposed to the outside air) is estimated based on the outside air temperature detected based on the vehicle speed detected based on the detection signal of the speed detection sensor 38 (step S16). ). For example, the ECU 50 subtracts the heat release amount obtained from the outside air temperature and the vehicle speed from the exhaust gas temperature to estimate the exhaust pipe temperature.

  Next, the ECU 50 determines whether or not the estimated exhaust pipe temperature is less than a predetermined temperature (step S17). The predetermined temperature is, for example, about 300 ° C., which is a temperature at which the hay ignites. The predetermined temperature is not limited to 300 ° C., and may be set as appropriate according to the environment.

  When the estimated exhaust pipe temperature is equal to or higher than the predetermined temperature (step S17 / NO), if the filter regeneration process is performed and there is a combustible material around the exhaust pipe, the combustible material may ignite. The filter regeneration process is prohibited (step S21).

  On the other hand, when the estimated exhaust pipe temperature is lower than the predetermined temperature (step S17 / YES), the ECU 50 performs a filter regeneration process (step S19). At this time, for example, a message such as “DPF regeneration is in progress. Check if there are any flammables in the surroundings” on the multi-information display, or by flashing the DPF lamp, the driver is performing filter regeneration. It is preferable to notify that there is.

  As described above in detail, the engine system 500 is provided in the exhaust passage 12 of the engine 10 and includes a particulate collection filter 42 that collects particulate matter contained in the exhaust gas, and the particulate collection filter 42. An ECU 50 that regenerates the particulate collection filter 42 by burning and incinerating the particulate matter deposited on the filter when it is determined that the particulate matter more than a predetermined amount has been deposited. The ECU 50 determines the state of the road surface on which the vehicle travels, and prohibits the regeneration of the particulate collection filter 42 based on the determined road surface state. As a result, when the vehicle is traveling on an uneven road, the filter regeneration process is prohibited. Therefore, even if the clearance between the exhaust pipe and the road surface is short, combustibles such as hay are in contact with the exhaust pipe and are combustible. Can be prevented from firing. Therefore, the filter regeneration process can be executed safely.

  In addition, although the said embodiment demonstrated the example in which the oxidation catalyst and the particulate collection filter were comprised separately, the catalyst (fine particulate collection filter) with which various catalysts and the particulate collection filter were integrated was used. May be.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto, and various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

DESCRIPTION OF SYMBOLS 10 Engine 12 Exhaust passage 42 Fine particle collection filter 50 ECU (reproduction | regeneration part, discrimination | determination part, prohibition part)
500 Engine system (control device for internal combustion engine)

Claims (1)

A filter provided in an exhaust passage of an internal combustion engine mounted on a vehicle and collecting particulate matter contained in exhaust gas;
When it is determined that a predetermined amount or more of particulate matter has been deposited on the filter, a regeneration unit that regenerates the filter by burning and incinerating the particulate matter deposited on the filter;
A discriminating unit for discriminating a state of a road surface on which the vehicle travels;
A prohibition unit for prohibiting regeneration of the filter by the regeneration unit based on the determined state of the road surface;
A control device for an internal combustion engine.

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