Exhaust purification device removal determination device

Abstract

The present invention relates to a removal determination device of an exhaust purification device which determines whether or not the exhaust purification device is housed inside a housing which communicates with an exhaust pipe of an engine, and in the case where the input temperature detected by an input temperature sensor has decreased within a prescribed period from the start of the engine, outputs the input temperature detected by the input temperature sensor before the decrease, and determines whether or not the exhaust purification device is disposed inside the housing on the basis of the output input temperature and the output temperature detected by an output temperature sensor.

Description

Technical Field

[0001] This invention relates to a device for determining whether an exhaust purification apparatus for an engine has been removed from the exhaust pipe. Background Technology

[0002] Japanese Patent Application Publications (JP2024-036090) to JP2019-214952 disclose a device for determining whether an exhaust purification device has been removed from an exhaust pipe. The determining device described in JP2024-036090 is configured to determine whether the exhaust purification device has been removed at a point in time when the cumulative amount of exhaust gas from the engine reaches a predetermined amount or more. Furthermore, the determining device is configured to determine that the exhaust purification device has been removed if the difference between the detection value of a temperature sensor installed upstream of the location where the exhaust purification device is installed and the detection value of a temperature sensor installed downstream is less than a predetermined difference.

[0003] The determining device described in Japanese Patent Application Publication No. 2019-218917 is configured to determine whether an exhaust gas purification device has been removed based on a first cumulative value and a second cumulative value. The first cumulative value is a value obtained by accumulating the temperature change of the exhaust gas upstream of the exhaust gas purification device. The second cumulative value is a value obtained by accumulating the change in the difference between the exhaust gas temperature upstream of the exhaust gas purification device and the exhaust gas temperature downstream of the exhaust gas purification device.

[0004] The determining device described in Japanese Patent Application Publication No. 2019-214952 estimates the temperature of the downstream side of the exhaust gas purification device based on the temperature of the upstream side of the device. Furthermore, it is configured to determine whether the exhaust gas purification device has been removed by comparing the estimated temperature with the actual temperature. It should be noted that the determining device described in Japanese Patent Application Publication No. 2019-214952 is configured to determine whether the exhaust gas purification device has been removed under certain preconditions. These preconditions include the engine coolant temperature being above a specified temperature, the ambient temperature being within a specified temperature range, the engine running for at least a specified time after starting, the engine speed being within a specified range, and the device not being in the regeneration phase of the exhaust gas purification device. Summary of the Invention

[0005] The determination device described in Japanese Patent Application Publication Nos. 2024-036090 to 2019-214952 determines whether an exhaust gas purification device has been removed based on the exhaust gas temperature upstream of the device. On the other hand, the removal of the exhaust gas purification device is determined based on the rising trend of the exhaust gas temperature detected by a temperature sensor, starting from a state where the internal combustion engine temperature has sufficiently decreased. Furthermore, during the operation of the internal combustion engine, water is generated by the reaction of hydrogen and oxygen contained in the air, and this water is contained in the exhaust gas. Therefore, when determining the presence or absence of an exhaust gas purification device, there is a possibility that the water contained in the exhaust gas condenses, changes phase to a liquid phase, and flows within the exhaust pipe. In such a case, the detection section of the temperature sensor located upstream of the exhaust gas purification device may become wet. As a result, the heat near the detection section of the temperature sensor is absorbed as the heat of vaporization associated with the change of the liquid phase of water attached to the detection section to a gas phase, and the temperature detected by the temperature sensor may be lower than the actual exhaust gas temperature. Sometimes, even when the detection section of the temperature sensor is wet, the determination of whether the exhaust gas purification device has been removed is based on the temperature detected by the temperature sensor. In this situation, it is possible to mistakenly assume that the exhaust purification device has been removed even though it has not been removed.

[0006] This invention was made in view of the above-mentioned technical problems. The purpose of this invention is to provide an exhaust purification device removal determination device that can suppress false determinations of whether the exhaust purification device has been removed.

[0007] To achieve the above objectives, the present invention provides an exhaust gas purification device removal determination device that determines whether an exhaust gas purification device is housed inside a housing connected to the engine's exhaust pipe.

[0008] The removal determination device for the exhaust purification device includes:

[0009] An input temperature sensor is used to detect the temperature on the upstream side of the housing;

[0010] Output temperature sensor to detect the temperature on the downstream side of the housing; and

[0011] The controller determines whether the exhaust purification device is present within the housing.

[0012] The controller has:

[0013] The noise removal processing unit, if the input temperature detected by the input temperature sensor decreases within a predetermined period from when the engine starts, outputs the input temperature detected by the input temperature sensor before the decrease; and

[0014] The determination unit determines whether the exhaust purification device is installed inside the housing based on the input temperature output from the noise removal processing unit and the output temperature detected by the output temperature sensor.

[0015] Alternatively, in this invention, the specified period may include the period from when the engine is started until the output temperature reaches the specified temperature.

[0016] Alternatively, in this invention, if the ratio of the cumulative value of the input temperature output from the noise removal processing unit during the specified period to the cumulative value of the output temperature during the specified period is a specified value or higher, the determination unit determines that the exhaust purification device is disposed in the housing.

[0017] Furthermore, in this invention, the controller may also include an engine stop time acquisition unit, which acquires the time from when the engine stops until when the engine starts.

[0018] If the time from when the engine stops to when the engine starts is more than a predetermined time, the determination unit determines whether the exhaust purification device is installed in the housing.

[0019] The exhaust gas purification device removal determination device of the present invention outputs the input temperature detected by the input temperature sensor located upstream of the exhaust gas purification device before the temperature drop occurs within a predetermined period from engine start-up. That is, the input temperature before the temperature drop detected by the input temperature sensor is set as a lower limit protection value. Furthermore, it determines whether an exhaust gas purification device is installed based on the input temperature before the temperature drop detected by the input temperature sensor and the output temperature detected by the output temperature sensor located downstream of the exhaust gas purification device. Therefore, even if the input temperature detected by the input temperature sensor drops due to water or other reasons, the drop in input temperature can be suppressed from affecting the determination value used to determine the presence or absence of the exhaust gas purification device. As a result, false determinations of the presence or absence of the exhaust gas purification device can be suppressed; in other words, the accuracy of determining the presence or absence of the exhaust gas purification device can be improved. Attached Figure Description

[0020] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, wherein the same reference numerals denote the same constituent elements, and wherein:

[0021] Figure 1 This is a schematic diagram illustrating an example of an engine equipped with the exhaust purification device according to an embodiment of the present invention;

[0022] Figure 2 It is a block diagram used to illustrate the functional structure of the controller;

[0023] Figure 3 This is a flowchart illustrating an example of control performed by the removal determination device according to an embodiment of the present invention;

[0024] Figure 4 This is a timing diagram used to illustrate the changes in input and output temperatures when the detection part of the input temperature sensor is wetted;

[0025] Figure 5 This is a timing diagram showing the changes in input and output temperatures when the GPF is removed from the housing. Detailed Implementation

[0026] The present invention will be described based on the illustrated embodiments. Furthermore, the embodiments described below are merely examples of how the present invention is embodied and do not limit the scope of the invention.

[0027] exist Figure 1 The diagram schematically illustrates an example of an engine and exhaust purification device for which the removal determination device of the present invention is applied. Figure 1 The engine 1 shown is configured similarly to conventional engines to generate power by burning a mixture of fuels such as gasoline and diesel with air. Specifically, in engine 1, multiple cylinders 2 for burning the mixture are formed in the engine block 3. Each cylinder 2 is equipped with a spark plug 4 for igniting the mixture.

[0028] An intake pipe 5 for drawing in outside air is connected to the engine block 3 via an intake manifold 6. In addition to various components such as an air filter (not shown), the intake pipe 5 is equipped with a throttle valve 7 for controlling the amount of air flowing within the intake pipe 5 based on the driver's accelerator input. A throttle valve opening sensor 8 is installed in the intake pipe 5 to detect the opening degree of the throttle valve 7.

[0029] An exhaust pipe 9 is connected to the engine block 3 via an exhaust manifold 10. The exhaust pipe 9 is used to discharge the exhaust generated by the combustion of the air-fuel mixture in each cylinder 2 to the outside of the vehicle.

[0030] The exhaust pipe 9 is equipped with various devices for purifying unburned gases (carbon monoxide (CO) and hydrocarbons (HC)) and nitrogen oxides (NOx) contained in the exhaust gas, and for capturing particulate matter. Figure 1 In the example shown, an oxidation catalyst (binary catalyst) or three-way catalyst for purifying unburned gas and NOx is installed in the exhaust pipe 9, and a PM collection device 12 for capturing particulate matter is installed downstream of the catalyst device 11.

[0031] In an embodiment of the present invention, a wall-flow type filter 13 is used as the exhaust gas purification device, i.e., the PM collection device 12. Specifically, the PM collection device 12 is a filter 13 called a GPF (Gasoline Particulate Filter), in which a three-way catalyst is carried. Therefore, unburned gases and NOx contained in the exhaust gas discharged from the catalyst device 11 can be effectively purified by the PM collection device 12. In the following description, the filter 13 will be simply referred to as GPF 13.

[0032] GPF13 has an outer diameter approximately the same as the inner diameter of a housing 14 formed by expanding a portion of the exhaust pipe 9, and is assembled inside the housing 14. That is, the housing 14 is disposed in communication with the exhaust pipe 9, and is configured such that all exhaust flowing into the housing 14 passes through the interior of GPF13.

[0033] To detect the temperature of the exhaust gas flowing into the GPF13, an input temperature sensor 15 is provided between the catalyst unit 11 and the GPF13. Furthermore, to detect the temperature of the exhaust gas flowing out of the GPF13, an output temperature sensor 16 is provided downstream of the GPF13. In other words, the input temperature sensor 15 detects the temperature upstream of the housing 14, and the output temperature sensor 16 detects the temperature downstream of the housing 14. It should be noted that the exhaust gas temperature detection section 15a in the input temperature sensor 15 protrudes a predetermined amount within the exhaust pipe 9, and similarly, the exhaust gas temperature detection section 16a in the output temperature sensor 16 protrudes a predetermined amount within the exhaust pipe 9.

[0034] The throttle opening sensor 8, the temperature sensors 15 and 16, and the timer 17 described above are connected to an electronic control device (hereinafter referred to as ECU) 18, which is equivalent to the "controller" in the embodiment of the present invention. The timer 17 is configured to measure the elapsed time (time of rest) from when the ignition is turned off.

[0035] Like previous ECUs, ECU18 is primarily composed of a microcomputer, and it determines the presence or absence of GPF13 based on input signals and pre-stored mappings and formulas. It should be noted that signals from other sensors, such as those from sensors that detect engine speed, can also be input into ECU18.

[0036] exist Figure 2 The diagram shown illustrates the functional structure of ECU18. Figure 2 The ECU18 shown includes a rest time acquisition unit 19, a temperature acquisition unit 20, a noise removal processing unit 21, a judgment value calculation unit 22, and a GPF judgment unit 23.

[0037] The standby time acquisition unit 19 functions as an "engine stop time acquisition unit" that acquires the time from stopping the engine 1 to starting it. In an embodiment of the present invention, the standby time measured by the standby timer 17 is sent to the standby time acquisition unit 19.

[0038] The temperature acquisition unit 20 is configured to acquire the temperature detected by the input temperature sensor 15 and the output temperature sensor 16, and output it to the noise removal processing unit 21 and the judgment value calculation unit 22.

[0039] The noise removal processing unit 21 suppresses the detection value from being lower than the actual exhaust temperature, primarily due to factors such as water contamination of the detection section 15a in the input temperature sensor 15. Specifically, it is configured to output the input temperature detected by the input temperature sensor 15 before the input temperature dropped if the input temperature detected by the input temperature sensor 15 decreases within a predetermined period from engine start-up. More specifically, if the input temperature detected by the input temperature sensor 15 drops, it sets the temperature at the point in time when the input temperature begins to drop as a lower limit protection value. Thus, it is configured to suppress the drop in input temperature output from the noise removal processing unit 21. The noise removal processing unit 21 outputs a signal to the determination value calculation unit 22.

[0040] The determination value calculation unit 22 calculates a determination value for determining whether the GPF13 is installed based on the exhaust temperature input from the temperature acquisition unit 20 and the noise removal processing unit 21. In the example shown here, the determination value is calculated as the ratio of the cumulative value of the input temperature input from the noise removal processing unit 21 to the cumulative value of the output temperature input from the temperature acquisition unit 20 within a specified period.

[0041] The GPF determination unit 23 is configured to determine that the GPF 13 is disposed inside the housing 14 when the determination value calculated by the determination value calculation unit 22 is above a predetermined value. Furthermore, the GPF determination unit 23 is configured to determine that the GPF 13 is removed from the housing 14 when the determination value is below the predetermined value. This GPF determination unit 23 corresponds to the "determination unit" in the embodiments of the present invention.

[0042] Figure 3A flowchart illustrating an example of control executed by ECU 18 is shown. This control example is repeated in each control cycle of ECU 18. In S1, it is determined whether the dwell time is longer than a predetermined time. This predetermined time is set based on experimental and simulation results and is the time required for the temperature inside the engine 1 and exhaust pipe 9 to drop to the same temperature as the external gas. It should be noted that the removal determination device in this embodiment is sometimes applicable to hybrid electric vehicles that can stop the engine 1 and operate using an electric motor as another driving force source. In this case, in S1, it is also possible to determine whether the elapsed time since the engine 1 was stopped is longer than the predetermined time, instead of the dwell time. Thus, in S1, it is determined whether the time from stopping the engine 1 to starting the engine 1 is longer than the predetermined time.

[0043] In this control example, the presence or absence of GPF13 is determined based on the exhaust temperature detected by the input temperature sensor 15 and the output temperature sensor 16. Therefore, if the exhaust temperature in engine 1 and exhaust pipe 9 is relatively high immediately after engine 1 has been stopped, it may be difficult to accurately determine the presence or absence of GPF13. Therefore, if a negative determination is made in S1 because the dwell time is not longer than the predetermined time, the routine is temporarily terminated.

[0044] Conversely, if a positive judgment is made in S1 because the dwell time exceeds a predetermined time, proceed to S2 to determine whether it is within a predetermined time since the engine was started. Specifically, determine whether it is within the period from the start of engine 1 until the output temperature detected by output temperature sensor 16 reaches a predetermined temperature. It should be noted that S2 is a step used to determine whether it is within the period for determining whether GPF 13 is installed. The predetermined time can be a time predetermined by experiments or determined by the cumulative amount of intake air.

[0045] If a negative judgment is made in S2 because the time elapsed since the engine started is not within the specified time, the routine is temporarily terminated. Conversely, if a positive judgment is made in S2 because the time elapsed since the engine started is within the specified time, the process proceeds to S3 to obtain the exhaust temperature (hereinafter referred to as the input temperature) Tin(t) detected by the input temperature sensor 15. Then, the process proceeds to S4 to determine whether the input temperature Tin(t) detected in S3 is greater than or equal to the input temperature Tin(t-1) used in the previous routine. That is, it is determined whether the input temperature has decreased.

[0046] If the input temperature Tin(t) detected in S3 is greater than or equal to the input temperature Tin(t-1) used in the previous routine, and a positive judgment is made in S4, then proceed to S5 and output the input temperature Tin(t) detected in S3. Conversely, sometimes a negative judgment is made in S4 because the input temperature Tin(t) detected in S3 is less than the input temperature Tin(t-1) used in the previous routine. In this case, it is presumed that the input temperature has decreased due to water contamination of the detection section 15a of the input temperature sensor 15. This is because it is assumed that within a predetermined time from engine start-up, the exhaust temperature in the exhaust pipe 9 gradually increases as the engine 1 burns; in other words, it is assumed that the exhaust temperature in the exhaust pipe 9 does not decrease. Therefore, if a negative judgment is made in S4, proceed to S6 and output the input temperature Tin(t-1) used in the previous routine.

[0047] Next, in steps S5 and S6, and then in step S7, the input temperature Tin(t) output from S5 or the input temperature Tin(t-1) output from S6 is accumulated to obtain the accumulated input temperature Sin. That is, the input temperature is accumulated sequentially from the time the engine starts. Next, in step S8, the exhaust temperature (hereinafter referred to as the output temperature) Tout detected by the output temperature sensor 16 is detected. In step S9, this output temperature Tout is accumulated to obtain the accumulated output temperature Sout. That is, the output temperature is accumulated sequentially from the time the engine starts.

[0048] like Figure 1 In the engine 1 configured as shown, after the input temperature Tin(t) rises, the GPF 13 heats up, and then the output temperature Tout(t) heats up. That is, when the GPF 13 is installed in the exhaust pipe 9, the output temperature Tout(t) heats up later than the input temperature Tin(t) based on the heat capacity of the GPF 13. Furthermore, in this control example, the presence or absence of the GPF 13 is determined after both the input temperature Tin(t) and the output temperature Tout(t) have increased. Therefore, in S10 following S9, it is determined whether the output temperature Tout(t) is above a predetermined temperature. This predetermined temperature in S10 can be set, for example, above the dew point temperature of water.

[0049] If a negative judgment is made in S10 because the output temperature Tout(t) is less than the specified temperature, the presence or absence of GPF13 cannot be accurately determined, so the routine is temporarily terminated. That is, before a positive judgment is made in S10 because the output temperature Tout(t) becomes above the specified temperature, the input temperature Tin(t) or the input temperature Tin(t-1) is accumulated, and the output temperature Tout(t) is continuously accumulated. Conversely, if a positive judgment is made in S10 because the output temperature Tout(t) is above the specified temperature, the process proceeds to S11, where the judgment value Sin / Sout is calculated. Specifically, the accumulated input temperature Sin relative to the accumulated output temperature Sout is calculated.

[0050] Then, in S12, it is determined whether the judgment value Sin / Sout calculated by S11 is above or equal to a predetermined value obtained through experiments, simulations, etc. If a positive judgment is made in S12 because the judgment value is above the predetermined value, it is determined to be normal in S13, and the routine is temporarily terminated. That is, it is determined that GPF13 is installed inside housing 14. Conversely, if a negative judgment is made in S12 because the judgment value is below the predetermined value, it is determined to be abnormal in S14, and the routine is temporarily terminated. That is, it is determined that GPF13 has been removed from housing 14. In this case, it is preferable to notify the driver by illuminating the instrument panel, etc. It should be noted that when S13 and S14 are executed, the aforementioned cumulative input temperature Sin and cumulative output temperature Sout are reset to zero.

[0051] exist Figure 4 The diagram shows a timing graph illustrating the changes in input temperature Tin and output temperature Tout when the detection section 15a of the input temperature sensor 15 is temporarily wetted by condensation after engine 1 is started. It should be noted that the solid line represents the input temperature Tin detected by the input temperature sensor 15, the thick line represents the cumulative input temperature, and the dashed line represents the output temperature Tout detected by the output temperature sensor 16. Additionally, the dotted line represents the input temperature when the detection section 15a of the input temperature sensor 15 is not wetted, in other words, the actual exhaust temperature.

[0052] exist Figure 4 In the example shown, engine 1 starts at time t0. After increasing the engine speed to a specified speed, engine 1 ignites the air-fuel mixture to start. The mixture then burns, producing high-temperature exhaust gas that reaches the input temperature sensor 15. Therefore, at... Figure 4 In the example shown, the input temperature Tin increases starting from a time delay of t0.

[0053] On the other hand, immediately after the engine starts, the air in engine 1 and exhaust pipe 9 contains moisture. Therefore, the exhaust temperature is absorbed as heat of vaporization of the water, resulting in a slow increase in input temperature Tin, or a stagnation near the dew point, before the exhaust temperature reaches a predetermined temperature t1 that is higher than the dew point temperature. Furthermore, when the exhaust temperature exceeds the dew point temperature, the exhaust temperature begins to increase, thereby causing the input temperature Tin to increase.

[0054] exist Figure 4 In the example shown, at time t2 after the input temperature Tin(t) begins to increase, the detection section 15a of the input temperature sensor 15 becomes wet, thereby causing the temperature detected by the input temperature sensor 15 to begin to decrease. Therefore, by... Figure 3 In step S4, a negative judgment is made, and the input temperature Tin(t-1) used in the previous routine is accumulated. That is, the input temperature Tin(t) detected by the input temperature sensor 15 due to the vaporization of moisture attached to the detection unit 15a of the input temperature sensor 15 becomes higher than the input temperature Tin(t-1) at time point t3, and the input temperature Tin(t-1) is continuously accumulated.

[0055] In addition, Figure 4 In the example shown, the output temperature Tout detected by the output temperature sensor 16 starts to increase at time t4, and the output temperature Tout reaches the specified temperature at time t5.

[0056] Therefore, the cumulative input temperature Sin becomes the heat equivalent to the area of ​​the region shown by the dot, and conversely, the cumulative output temperature Sout becomes the heat equivalent to the area of ​​the region shown by the shaded area. Therefore, the ratio of the cumulative input temperature Sin to the cumulative output temperature Sout (Sin / Sout), i.e., the determination value, becomes a larger value. As a result, by determining that the determination value is larger than the specified value, it is determined that the GPF13 is installed within the housing 14.

[0057] It should be noted that, in Figure 5 The diagram shows the changes in input temperature Tin and output temperature Tout when GPF13 is removed from housing 14. Figure 5In the example shown, at time t4', slightly delayed from time t1, the output temperature Tout begins to increase and reaches the specified temperature at time t5'. This is because, by removing the GPF13 from the housing 14, the heat from the exhaust is not absorbed by the GPF13, and the exhaust temperature is measured by the output temperature sensor 16 with a delay corresponding to the exhaust flow rate. Therefore, when the GPF13 is removed from the housing 14, the output temperature Tout reaches the specified temperature at a time when the increase in the input temperature Tin is small, thereby reducing the difference between the cumulative input temperature Sin and the cumulative output temperature Sout. As a result, the judgment value becomes smaller than the specified value, indicating that the GPF13 has been removed from the housing 14.

[0058] As described above, if the input temperature Tin(t) detected by the input temperature sensor 15 decreases within a specified period from engine start-up, the cumulative input temperature Sin is calculated using the input temperature Tin(t-1) used in the previous routine. This prevents the judgment value from decreasing and suppresses false judgments that the GPF13 has been removed from the housing 14. In other words, even if the input temperature Tin(t) decreases due to moisture or other factors such as water contamination of the detection section 15a in the input temperature sensor 15, it is possible to determine with high accuracy whether the GPF13 is installed inside the housing 14.

[0059] It should be noted that the removal determination device in this embodiment of the invention only needs to use the input temperature Tin(t-1) before the decrease in the input temperature Tin(t) detected by the input temperature sensor 15 to determine the presence or absence of GPF13, and the determination method is not limited. That is, sometimes the presence or absence of GPF13 is determined based on the temperature difference between the input temperature and the output temperature at a predetermined timing, or the temperature difference between the estimated output temperature based on the input temperature and the actual output temperature at a predetermined timing. In this case, the input temperature Tin(t-1) before the decrease in the input temperature can also be used to determine the presence or absence of GPF13.

Claims

1. A device for determining the removal of an exhaust purification device, wherein the device determines that an exhaust purification device is housed inside a housing connected to the exhaust pipe of an engine. The removal determination device for the exhaust purification device includes: An input temperature sensor is used to detect the temperature on the upstream side of the housing; Output temperature sensor to detect the temperature on the downstream side of the housing; and The controller determines whether the exhaust purification device is present within the housing. The controller has: The noise removal processing unit, if the input temperature detected by the input temperature sensor decreases within a predetermined period from when the engine starts, outputs the input temperature detected by the input temperature sensor before the decrease; and The determination unit determines whether the exhaust purification device is installed inside the housing based on the input temperature output from the noise removal processing unit and the output temperature detected by the output temperature sensor.

2. The removal determination device for the exhaust gas purification device according to claim 1, wherein, The specified period includes the period from when the engine is started until the output temperature reaches the specified temperature.

3. The removal determination device for the exhaust gas purification device according to claim 1, wherein, If the ratio of the cumulative value of the input temperature output from the noise removal processing unit during the specified period to the cumulative value of the output temperature during the specified period is a specified value or higher, the determination unit determines that the exhaust purification device is disposed in the housing.

4. The removal determination device for the exhaust gas purification device according to claim 1, wherein, The controller also includes an engine stop time acquisition unit, which acquires the time from when the engine stops until when the engine starts. If the time from when the engine stops to when the engine starts is more than a predetermined time, the determination unit determines whether the exhaust purification device is installed in the housing.

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