Separation determination device for exhaust purification device

Abstract

An exhaust gas purification device detachment determination device is provided, which can improve the accuracy of determining whether the exhaust gas purification device has detached from the exhaust pipe. It includes: an input temperature sensor (15) for detecting the temperature on the upstream side of the housing (14) connected to the exhaust pipe (9) of the engine (1); and an output temperature sensor (16) for detecting the temperature on the downstream side of the housing (14); and includes: an engine stop time acquisition unit (19) for acquiring the time from engine (1) stopping to starting; and a determination unit (22) for determining whether an exhaust gas purification device (13) is disposed in the housing (14) if the time from engine (1) stopping to starting is more than a predetermined time preset, based on the input temperature detected by the input temperature sensor (15) and the output temperature detected by the output temperature sensor (16).

Description

Technical Field

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

[0002] Patent Document 1 describes an exhaust system comprising an outer cylinder connected to an exhaust pipe, an inner cylinder disposed on the central axis of the outer cylinder at a predetermined interval from the inner surface of the outer cylinder, an HC adsorption material disposed between the outer and inner cylinders, and a switching valve disposed on the upstream side of the inner cylinder. In this exhaust system, by using the switching valve to close the upstream side of the inner cylinder, exhaust flows downstream only through a bypass flow path between the outer and inner cylinders. Conversely, by using the switching valve to open the upstream side of the inner cylinder, exhaust flows downstream through the bypass flow path and the hollow portion of the inner cylinder (hereinafter referred to as the normal flow path).

[0003] Patent Document 1 describes a diagnostic device for diagnosing malfunctions in a switching valve. This diagnostic device includes a first temperature sensor located downstream of the inner cylinder and a second temperature sensor located upstream of the bypass flow path. Specifically, the diagnostic device is configured to diagnose malfunctions in the switching valve based on whether the difference between the cumulative temperature value detected by the first temperature sensor (i.e., a first temperature area) after engine startup and the cumulative temperature value detected by the second temperature sensor (i.e., a second temperature area) corresponds to the opening / closing indication of the switching valve.

[0004] When the exhaust flows only in one of the aforementioned bypass flow path and normal flow path, and the vehicle is driven for short periods of time repeatedly, it is possible that the initial temperature detected by the sensor installed in one of the paths is high, leading to a false diagnosis of a switching valve malfunction. Therefore, the diagnostic device described in Patent Document 1 is configured to diagnose a switching valve malfunction only when the engine coolant temperature at engine start is less than a threshold, the decrease in engine coolant temperature from the end of the previous stroke is greater than the threshold, and the cumulative intake air volume in the previous stroke is greater than the threshold.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2008-121509 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The order in which the temperature sensors receive exhaust heat, as described in Patent Document 1, differs depending on whether the switching valve is open or closed. Therefore, based on the relationship (i.e., the temperature difference) between the first temperature area (based on the temperature detected by the first temperature sensor) and the second temperature area (based on the temperature detected by the second temperature sensor), it is possible to determine whether the switching valve has become "inoperable." Currently, exhaust purification devices such as gasoline particulate filters (hereinafter referred to as GPFs) installed in the exhaust pipe are sometimes intentionally removed from the exhaust pipe due to theft or other reasons. Even if the exhaust purification device is detached from the exhaust pipe in this way, the exhaust flow direction does not change regardless of whether the exhaust purification device is present or not, so the fault diagnosis device described in Patent Document 1 cannot be directly applied. Therefore, there is room for developing a device for highly accurate determination of situations where the exhaust purification device has been detached.

[0010] This invention addresses the aforementioned technical issues and aims to provide a device for determining whether an exhaust purification device has detached from the exhaust pipe, thereby improving the accuracy of determining whether the exhaust purification device has detached from the exhaust pipe.

[0011] Technical solutions for solving the problem

[0012] To achieve the above objective, the present invention provides an exhaust gas purification device detachment determination device that determines whether an exhaust gas purification device is housed inside a housing connected to the exhaust pipe of an engine. The device is characterized by comprising: an input temperature sensor for detecting the temperature upstream of the housing; an output temperature sensor for detecting the temperature downstream of the housing; and a controller for determining whether the exhaust gas purification device is present inside the housing. The controller includes: an engine stop time acquisition unit for acquiring the time from engine stop to start; and a determination unit that, if the time from engine stop to start is greater than or equal to a predetermined time, determines whether the exhaust gas purification device is disposed inside the housing based on the input temperature detected by the input temperature sensor and the output temperature detected by the output temperature sensor.

[0013] In this invention, the controller may be configured to calculate the cumulative amount of exhaust gas from the start of the engine, and if the cumulative amount is greater than or equal to a predetermined amount, the determination unit may determine whether the exhaust gas purification device is disposed in the housing.

[0014] In this invention, the controller may be configured to pre-calculate a predetermined cumulative amount that, when the exhaust purification device is installed in the housing, causes the input temperature to be above the dew point temperature of the water and the output temperature to become below the dew point temperature, the predetermined amount including the predetermined cumulative amount.

[0015] In this invention, the controller may be configured such that, when the input temperature is above a predetermined temperature, the determination unit determines whether the exhaust purification device is disposed in the housing.

[0016] In this invention, if the difference between the input temperature and the output temperature at the time point when the cumulative amount of exhaust gas from the start of the engine reaches the first determination value is greater than or equal to a preset first threshold, the determination unit determines that the exhaust gas purification device is disposed in the housing.

[0017] In this invention, if the difference between the cumulative amount of exhaust gas from the start of the engine required for the input temperature to reach a preset first predetermined temperature and the cumulative amount required for the output temperature to reach the first predetermined temperature is a preset second threshold, the determination unit determines that the exhaust gas purification device is disposed in the housing.

[0018] In this invention, the determination unit may determine that the exhaust purification device is disposed in the housing if the difference between the cumulative amount of exhaust required for the input temperature to rise from the second predetermined temperature to the third predetermined temperature and the cumulative amount of exhaust required for the output temperature to rise from the second predetermined temperature to the third predetermined temperature is greater than or equal to a third predetermined threshold.

[0019] In this invention, if the time change rate of the output temperature corresponding to the time change rate of the input temperature at the time point when the input temperature reaches a preset fourth predetermined temperature is below a preset fourth threshold, the determination unit determines that the exhaust purification device is disposed in the housing.

[0020] Invention Effects

[0021] According to the present invention, when the time from engine shutdown to startup is longer than a predetermined time, it is determined whether an exhaust purification device for purifying engine exhaust is present in the exhaust pipe based on the input temperature and output temperature of the housing for housing the exhaust purification device. Therefore, it is possible to determine whether an exhaust purification device is present in the exhaust pipe based on the temperature drop within the engine and exhaust pipe. Furthermore, it is possible to prevent false determinations of the presence or absence of an exhaust purification device caused by changes in input temperature due to residual heat in the engine and exhaust pipe, or by changes in output temperature due to residual heat in the exhaust purification device. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating an example of an exhaust purification device in an embodiment of the present invention.

[0023] Figure 2 This is a flowchart illustrating an example of control performed by the determination device in an embodiment of the present invention.

[0024] Figure 3 The graph shows the results of verifying the relationship between the cumulative air volume and the temperature detected by each temperature sensor. (a) shows the verification results with a GPF installed in the exhaust pipe, and (b) shows the verification results without a GPF installed in the exhaust pipe.

[0025] Figure 4 The graphs compare the changes in input and output temperatures in relation to the engine shutdown time. (a) shows the changes in input and output temperatures when the engine is restarted for a short time, and (b) shows the changes in input and output temperatures when the engine is restarted for a long time.

[0026] Figure 5 The graphs show the results of verifying the relationship between the cumulative air volume and the time rate of change of input temperature and the time rate of change of output temperature. (a) shows the verification results with a GPF installed in the exhaust pipe, and (b) shows the verification results without a GPF installed in the exhaust pipe.

[0027] Figure 6 It is a graph showing the relationship between the elapsed time from engine start-up and the input and output temperatures.

[0028] Figure 7 This is a line graph showing the time change rate of the output temperature corresponding to the time change rate of the input temperature at the time point when the input temperature reaches the predetermined temperature, and determining whether there is a GPF.

[0029] Explanation of reference numerals in the attached figures

[0030] 1: Engine;

[0031] 8: Throttle opening sensor;

[0032] 9: Exhaust pipe;

[0033] 11: Catalyst unit;

[0034] 12: PM collection device;

[0035] 13: Gas purification device (GPF);

[0036] 14: Shell;

[0037] 15: Input temperature sensor;

[0038] 16: Output temperature sensor;

[0039] 17: Engine shutdown timer;

[0040] 18: Electronic Control Unit (ECU);

[0041] 19: The engine shutdown time is obtained from the department;

[0042] 20: Engine control unit;

[0043] 21: Temperature Acquisition Unit;

[0044] 22: GPF Judgment Department. Detailed Implementation

[0045] The present invention will be described based on the illustrated embodiments. Furthermore, the embodiments described below are merely examples embodying the present invention and are not intended to limit the invention.

[0046] An example of an engine and exhaust purification device using the disengagement determination device in an embodiment of the present invention is shown schematically. Figure 1 . Figure 1 The engine 1 shown is similar to existing engines in that it generates 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 (cylinder block) 3. Each cylinder 2 is provided with a spark plug 4 for igniting the mixture.

[0047] An intake pipe 5 for obtaining 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), a throttle valve 7 is provided in the intake pipe 5 to control the amount of air flowing within the intake pipe 5 based on the driver's accelerator input. A throttle valve opening sensor 8 is provided in the intake pipe 5 to detect the opening degree of the throttle valve 7.

[0048] In the engine block 3, an exhaust pipe 9 is connected via an exhaust manifold 10 for discharging exhaust gas generated by the combustion of the air-fuel mixture in each cylinder 2 to the outside of the vehicle.

[0049] 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 a three-way catalyst or other catalyst device 11 for purifying unburned gas and NOx is provided in the exhaust pipe 9, and a PM capture device 12 for capturing particulate matter is provided downstream of the catalyst device 11.

[0050] In embodiments of the present invention, a wall-flow type filter 13 is used as the exhaust 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, the PM collection device 12 can effectively purify unburned gases and NOx contained in the exhaust gas discharged from the catalyst unit 11. In the following description, the filter 13 will be simply referred to as GPF 13.

[0051] GPF13 has an outer diameter that is almost the same as the inner diameter of the housing 14 formed by the partial diameter expansion of the exhaust pipe 9, and is assembled inside the housing 14. That is, the housing 14 is configured to communicate with the exhaust pipe 9, and all exhaust flowing into the housing 14 passes through the interior of GPF13.

[0052] 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. In addition, 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.

[0053] The throttle opening sensor 8, the temperature sensors 15 and 16, and the ignition shut-off timer 17 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 ignition shut-off timer 17 is configured to measure the elapsed time (shut-off time) from when the ignition switch is turned off.

[0054] Like existing ECUs, ECU18 is primarily composed of a microcomputer and is configured to determine the presence or absence of GPF13 based on input signals and pre-stored mappings and formulas. Furthermore, ECU18 can also receive signals from other sensors, such as those from sensors that detect engine speed.

[0055] ECU18 includes an engine shutdown time acquisition unit 19, an engine control unit 20, a temperature acquisition unit 21, and a GPF determination unit 22. Specifically, the engine shutdown time acquisition unit 19 functions as an "engine stop time acquisition unit" that acquires the time from stopping the engine 1 to starting the engine 1. In an embodiment of the present invention, the engine shutdown time measured by the engine shutdown timer 17 is sent to the engine shutdown time acquisition unit 19.

[0056] The engine control unit 20 is configured to control the starting and stopping of the engine 1, and further, to control the output of the engine 1 according to requirements such as accelerator operation. The temperature acquisition unit 21 is configured to acquire the temperature detected by the input temperature sensor 15 and the output temperature sensor 16, and output it to the GPF determination unit 22. The GPF determination unit 22 is configured to determine whether the GPF 13 has been removed (detached) from the exhaust pipe 9 based on the temperature information input from the temperature acquisition unit 21. In other words, it is configured to confirm whether the GPF 13 is present in the exhaust pipe 9. This GPF determination unit 22 is equivalent to the "determination unit" in the embodiment of the present invention.

[0057] Figure 2 The diagram shows a flowchart illustrating an example of control performed by ECU 18. In this control example, when engine 1 is started from a state where the engine temperature is below a predetermined temperature, it is determined whether GPF 13 is present. In step S1, it is determined whether the preconditions for determining the presence or absence of GPF 13 are met. Specifically, in step S1, it is determined whether the engine shutdown time is greater than or equal to a predetermined time. This predetermined time is set based on experimental and simulation results as "the time required for the temperature inside engine 1 and exhaust pipe 9 to drop to the same temperature as the outside air". Furthermore, in the case where the disengagement determination device in this embodiment is applied to a hybrid vehicle that can stop engine 1 and drive by a motor as another driving force source, step S1 may also determine whether the elapsed time from when engine 1 is stopped is greater than or equal to the predetermined time, instead of the engine shutdown time. In this way, in step S1, it is determined whether the time from when engine 1 is stopped to when engine 1 is started is greater than or equal to the predetermined time.

[0058] If a negative judgment is made in step S1 because the preconditions for determining the presence or absence of GPF13 in exhaust pipe 9 are not met, the routine is temporarily terminated. Conversely, if a positive judgment is made in step S1 because the preconditions for determining the presence or absence of GPF13 in exhaust pipe 9 are met, the process proceeds to step S2 to determine whether the environmental conditions for determining the presence or absence of GPF13 are met. Specifically, in step S2, a determination is made regarding whether the environment is above a predetermined pressure set according to regulations.

[0059] If a negative judgment is made in step S2 due to unfavorable environmental conditions, the routine is temporarily terminated. Conversely, if a positive judgment is made in step S2 due to favorable environmental conditions, the process proceeds to step S3 to determine whether engine 1 has started. The determination in step S3 can be based, for example, on signals output from engine control unit 20 to engine 1.

[0060] If a negative judgment was made in step S3 because engine 1 has not started, the process returns to step S1, and the judgment in step S3 is repeated until engine 1 starts. Conversely, if a positive judgment was made in step S3 because engine 1 has started, the process proceeds to step S4 to determine whether a monitoring prohibition condition is met. This monitoring prohibition condition is that the exhaust temperature does not increase almost constantly (monotonicly). Therefore, for example, the monitoring prohibition condition is met if engine 1 may stall, or if the output of engine 1 is increasing at or above a predetermined rate.

[0061] If a positive judgment is made in step S4 due to the monitoring prohibition condition being met, the routine temporarily ends. Conversely, if a negative judgment is made in step S4 due to the monitoring prohibition condition not being met, the process proceeds to step S5 to perform calculations on the detected parameters.

[0062] In this control example, the presence or absence of GPF13 in the exhaust pipe 9 is determined based on the temperature detected by the input temperature sensor 15 and the output temperature sensor 16, and the cumulative amount of exhaust gas supplied to GPF13. This cumulative amount of exhaust gas supplied to GPF13 can be calculated, for example, based on the detection value of the throttle opening sensor 8. For convenience, in the following description, the cumulative amount of exhaust gas supplied to GPF13 will be referred to as the cumulative air volume.

[0063] Figure 3 In (a), the results of verifying the relationship between the cumulative air volume and the temperature detected by each temperature sensor 15, 16 with GPF13 installed in the exhaust pipe 9 are shown. On the other hand, Figure 3 (b) shows the results of verifying the relationship between the cumulative air volume and the temperature detected by each temperature sensor 15, 16 when no GPF13 is installed in the exhaust pipe 9.

[0064] Figure 3 The verification shown was conducted by driving the test vehicle using the high-speed, high-acceleration test cycle mode (US06) based on the Supplemental Federal Test Procedure (SFTP) and the Harmonized Worldwide Harmonized Exhaust Gas Fuel Economy Test Method (WLTP). Furthermore, the WLTP-based driving mode is a more moderate driving mode compared to the US06-based driving mode. Figure 3 (a) and Figure 3 In (b), the thick curve shows the verification results of the above relationship when driving in the US06 driving mode, the thin curve shows the verification results of the above relationship when driving in the WLTP driving mode, the dashed line shows the input temperature detected by the input temperature sensor 15, and the solid line shows the output temperature detected by the output temperature sensor 16.

[0065] like Figure 3 As shown in (a), when the exhaust pipe 9 is equipped with a GPF13, when the cumulative air volume is below a predetermined amount G1, the difference between the input temperature and the output temperature is extremely small and almost constant (stagnant). In other words, the input temperature and the output temperature are stagnant. Subsequently, if the cumulative air volume increases compared to the predetermined amount G1, the input temperature begins to increase regardless of the driving mode, but the output temperature remains constant. Specifically, the input temperature and the output temperature stagnate at the dew point temperature of water. In addition, when the exhaust pipe 9 is equipped with a GPF13, the heat capacity of the exhaust pipe 9 increases due to the GPF13. In this case, if the cumulative air volume (the heat energy input to the GPF13) becomes more than the predetermined amount G1, the input temperature begins to rise. However, since the heat is absorbed by the GPF13, the output temperature remains stagnant in this situation.

[0066] On the other hand, such as Figure 3 As shown in (b), without the GPF13 installed in exhaust pipe 9, the difference between input and output temperatures is small regardless of the driving mode. Furthermore, due to the low flow resistance of the exhaust, exhaust containing a significant amount of moisture in exhaust pipe 9 is rapidly expelled. As a result, both input and output temperatures rise almost continuously.

[0067] Therefore, in the control example shown here, the presence or absence of GPF13 in the exhaust pipe 9 is determined based on the cumulative air volume and the temperature detected by each temperature sensor 15, 16. Therefore, in step S5, the cumulative air volume from the start of engine 1 is calculated.

[0068] In step S6, it is determined whether the determination start condition is met. Specifically, in step S6, it is determined whether a significant difference occurs between the input and output temperatures under the assumption that GPF13 is configured in the exhaust pipe 9. For example, as Figure 3 (a) and Figure 3 As shown in (b), it is determined whether the cumulative air volume has reached or exceeded a predetermined amount Gp, and / or whether the input temperature has reached or exceeded a predetermined temperature T1. More specifically, it is determined whether the cumulative air volume has reached a cumulative air volume that can be inferred to be an input temperature above the dew point temperature of the moisture and an output temperature below the dew point temperature of the moisture. This cumulative air volume is equivalent to the "predetermined amount" or "predetermined cumulative amount" in the embodiments of the present invention.

[0069] If a negative judgment is made in step S6 because the determination start condition is not met, the process returns to step S4. Conversely, if a positive judgment is made in step S6 because the determination start condition is met, the process proceeds to step S7, where a determination value for whether or not GPF13 is present in the exhaust pipe 9 is calculated.

[0070] Specifically, the calculation is equivalent to the difference between the input and output temperatures at a predetermined cumulative air volume Gp, which corresponds to the "first determination value". Therefore, the predetermined cumulative air volume Gp is ​​set based on results from experiments, simulations, etc., to a value that significantly increases the difference between the input and output temperatures when GPF13 is set, and becomes minimal when GPF13 is not set. Furthermore, the predetermined cumulative air volume Gp can also be set to a value different from the value used in the determination in step S6.

[0071] In step S7, the difference ΔG between the cumulative air volume required for the input temperature to reach the preset first predetermined temperature T1 and the cumulative air volume required for the output temperature to reach the first predetermined temperature T1 can also be calculated. Specifically, the first predetermined temperature T1 is set such that, when a GPF13 is installed in the exhaust pipe 9, the difference ΔG between the cumulative air volume required for the input temperature to reach the first predetermined temperature T1 and the cumulative air volume required for the output temperature to reach the first predetermined temperature T1 is greater than a predetermined value; when a GPF13 is not installed, the difference ΔG is less than or equal to the predetermined value. The first predetermined temperature T1 can be set in advance based on the results of experiments, simulations, etc.

[0072] In step S7, the difference between the cumulative air volume required to raise the input temperature from a preset second predetermined temperature T2 to a third predetermined temperature T3 and the cumulative air volume required to raise the output temperature from the second predetermined temperature T2 to the third predetermined temperature T3 can also be calculated. Specifically, the second predetermined temperature T2 and the third predetermined temperature T3 are set such that: when a GPF13 is installed in the exhaust pipe 9, the difference between the cumulative air volume required to raise the input temperature from the second predetermined temperature T2 to the third predetermined temperature T3 and the cumulative air volume required to raise the output temperature from the second predetermined temperature T2 to the third predetermined temperature T3 is greater than a predetermined value; when a GPF13 is not installed in the exhaust pipe 9, the difference between the cumulative air volume required to raise the input temperature from the second predetermined temperature T2 to the third predetermined temperature T3 and the cumulative air volume required to raise the output temperature from the second predetermined temperature T2 to the third predetermined temperature T3 is less than a predetermined value. The second predetermined temperature T2 and the third predetermined temperature T3 can be set in advance based on the results of experiments, simulations, etc.

[0073] In step S8, following step S7, it is determined whether a GPF13 is installed in the exhaust pipe 9 based on the determination value calculated in step S7. For example, if the difference between the input temperature and the output temperature (i.e., the determination value) at a predetermined cumulative air volume Gp is ​​calculated in step S7, it is determined in step S8 whether the determination value is greater than or equal to a preset first threshold. If the determination value is greater than or equal to the first threshold, it is determined that a GPF13 is installed in the exhaust pipe 9.

[0074] If, in step S7, the difference between the cumulative air volume required for the input temperature to reach the first predetermined temperature T1 and the cumulative air volume required for the output temperature to reach the first predetermined temperature T1 (i.e., the determination value) is calculated, it is determined whether the determination value is greater than or equal to a preset second threshold. If the determination value is greater than or equal to the second threshold, it is determined that GPF13 is installed in the exhaust pipe 9.

[0075] In step S7, if the difference (i.e., the determination value) between the cumulative air volume required for the input temperature to rise from the second predetermined temperature T2 to the third predetermined temperature T3 and the cumulative air volume required for the output temperature to rise from the second predetermined temperature T2 to the third predetermined temperature T3 is calculated, it is determined whether the determination value is greater than or equal to a preset third threshold. If the determination value is greater than or equal to the third threshold, it is determined that GPF13 is installed in the exhaust pipe 9.

[0076] If a positive judgment is made in step S8 due to the presence of GPF13 in exhaust pipe 9, the process proceeds to step S9, where it is determined that exhaust pipe 9 is functioning normally. The procedure then temporarily ends. Conversely, if a negative judgment is made in step S8 due to the absence of GPF13 in exhaust pipe 9, the process proceeds to step S10, where it is determined that exhaust pipe 9 is malfunctioning, and the procedure temporarily ends. In this case, the malfunction of exhaust pipe 9 can be communicated to the driver, and the operating conditions of engine 1 can be changed.

[0077] Figure 4 (a) shows an example in which the input and output temperatures are measured when the exhaust pipe 9 is equipped with a GPF 13 and the engine 1 is restarted in a short time (i.e., the shutdown time is less than a predetermined time). Figure 4 (b) shows an example where the input and output temperatures are measured when the exhaust pipe 9 is equipped with a GPF 13 and the engine 1 is restarted after a prolonged period (i.e., the engine shutdown time is longer than a predetermined time). Furthermore, in Figure 4 In the diagram, the solid line represents the input temperature, and the dashed line represents the output temperature.

[0078] like Figure 4As shown in (a), when the engine 1 is restarted for a short time, the initial temperature of the GPF13 is high, resulting in a high exhaust temperature through the GPF13 due to the engine 1 restarting. Consequently, the difference between the input temperature and the output temperature at the predetermined cumulative air volume Gp decreases. Alternatively, the difference between the cumulative air volume required to raise the output temperature to the first predetermined temperature T1 and the cumulative air volume required to raise the input temperature to the first predetermined temperature T2 decreases. Or, the difference between the cumulative air volume required to raise the input temperature from the second predetermined temperature T2 to the third predetermined temperature T3 and the cumulative air volume required to raise the output temperature from the second predetermined temperature T2 to the third predetermined temperature T3 decreases. Therefore, in this case, it is possible to mistakenly determine that the GPF13 is not installed in the exhaust pipe 9.

[0079] In contrast, such as Figure 4 As shown in (b), when the engine 1 is restarted after a prolonged period, the initial temperature of the GPF13 is low. Therefore, after the engine 1 is restarted, the output temperature stagnates near the dew point temperature until the GPF13 warms up. As a result, the difference between the input temperature and the output temperature at the predetermined cumulative air volume Gp increases. Alternatively, the difference between the cumulative air volume required to raise the output temperature to the first predetermined temperature T1 and the cumulative air volume required to raise the input temperature to the first predetermined temperature T2 increases. Alternatively, the difference between the cumulative air volume required to raise the input temperature from the second predetermined temperature T2 to the third predetermined temperature T3 and the cumulative air volume required to raise the output temperature from the second predetermined temperature T2 to the third predetermined temperature T3 increases. That is, it is possible to determine whether there is GPF13 in the exhaust pipe 9 when the temperature in the engine 1 and the exhaust pipe 9 has decreased. In other words, in this state, the heat energy remaining in the engine 1 and the exhaust pipe 9 does not affect the input temperature, and the heat energy remaining in the GPF13 does not affect the output temperature. Therefore, it can prevent misjudgment of the presence or absence of GPF13 in the exhaust pipe 9, and can accurately determine the presence or absence of GPF13 in the exhaust pipe 9.

[0080] Furthermore, in the control example described above, the presence or absence of GPF13 in the exhaust pipe 9 is determined based on the cumulative air volume, i.e., the heat energy input to GPF13. Therefore, it is unnecessary to set a threshold for determining the presence or absence of GPF13 in the exhaust pipe 9 according to the driving mode, and it also prevents the relationship between input and output temperatures from changing depending on the driving mode. As a result, the determination of the presence or absence of GPF13 is simplified.

[0081] Furthermore, by determining the presence or absence of GPF13 under conditions where there is a significant difference between the input and output temperatures when GPF13 is installed in the exhaust pipe 9, false determinations can be prevented. Specifically, the presence or absence of GPF13 in the exhaust pipe 9 is determined by the cumulative air volume, which is presumed to have an input temperature above the dew point temperature of the moisture and an output temperature below the dew point temperature of the moisture. Therefore, when GPF13 is installed in the exhaust pipe 9, the input temperature increases more sharply, while the output temperature stagnates below the dew point temperature. As a result, the difference between the input and output temperatures becomes significantly larger, improving the accuracy of determining the presence or absence of GPF13 in the exhaust pipe 9.

[0082] In addition, such as Figure 3 (a) and Figure 3 As shown in (b), when the exhaust pipe 9 is equipped with a GPF13, the input temperature increases when the cumulative air volume reaches or exceeds a predetermined amount G1, while the output temperature remains stagnant. On the other hand, when the exhaust pipe 9 is not equipped with a GPF13, both the input and output temperatures increase regardless of the cumulative air volume. In other words, when the cumulative air volume reaches or exceeds a predetermined amount G1, the rate of change of the output temperature is smaller with respect to the rate of change of the input temperature compared to the case where the exhaust pipe 9 is equipped with a GPF13, compared to the case where the exhaust pipe 9 is not equipped with a GPF13.

[0083] Figure 5 In (a), the relationship between the cumulative air volume and the rate of change of the input temperature with GPF13 installed in the exhaust pipe 9 is shown by a dashed line, and the relationship between the cumulative air volume and the rate of change of the output temperature with GPF13 installed in the exhaust pipe 9 is shown by a solid line. On the other hand, Figure 5 In (b), the relationship between the cumulative air volume and the time-varying rate of change of the input temperature is shown by a dashed line when the exhaust pipe 9 is not equipped with GPF13, and the relationship between the cumulative air volume and the time-varying rate of change of the output temperature is shown by a solid line when the exhaust pipe 9 is not equipped with GPF13. Additionally, with... Figure 3 (a) and Figure 3 (b) Similarly, the verification results for the US06-based driving mode are shown as a thick curve, and the verification results for the WLTP-based driving mode are shown as a thin curve.

[0084] like Figure 5 As shown in (a), when the exhaust pipe 9 is equipped with GPF13, when the cumulative air volume is above a predetermined amount G1, the time change rate of the input temperature increases sharply, while the time change rate of the output temperature remains low. (Refer to...) Figure 3As explained in (a), the output temperature stagnates near the dew point temperature of the moisture. Therefore, when the cumulative air volume is above a predetermined amount G1 in this case, the difference between the time change rate of the input temperature and the time change rate of the output temperature becomes larger.

[0085] In contrast, such as Figure 5 As shown in (b), when the exhaust pipe 9 is not equipped with GPF13, the difference between the time change rate of the input temperature and the time change rate of the output temperature increases or decreases regardless of the cumulative air volume. That is, there is no significant difference between the time change rate of the input temperature and the time change rate of the output temperature as is seen when the exhaust pipe 9 is equipped with GPF13.

[0086] Therefore, the detachment determination device in the embodiment of the present invention can be configured to determine whether the difference between the time change rate of the input temperature and the time change rate of the output temperature is greater than or equal to a predetermined difference when the cumulative air volume is a predetermined amount G1 or more, and determine that the GPF13 is detached (removed) when it is less than the predetermined difference.

[0087] When a vehicle using the disengagement determination device in an embodiment of the present invention undergoes rapid acceleration, the input and output temperatures rise briefly; conversely, when accelerating at a small acceleration, the input and output temperatures rise for a longer period. Therefore, it is necessary to set a threshold for determining whether GPF13 is present based on the driving mode, i.e., the drive mode of engine 1. To avoid such complex control... Figure 2 The control example shown is configured such that, given that the heat energy supplied to the exhaust pipe 9 is above a predetermined value, the input temperature and the output temperature are compared, thereby determining whether there is GPF13 in the exhaust pipe 9.

[0088] However, as Figure 6 As shown in (a), when GPF13 is installed in the exhaust pipe 9, the output temperature rises later than the input temperature after a predetermined time has elapsed since the engine 1 was started. On the other hand, as Figure 6 As shown in (b), when no GPF13 is installed in the exhaust pipe 9, the input temperature and output temperature rise almost simultaneously at a predetermined time point after the engine 1 has been started. Therefore, the disengagement determination device in the embodiment of the present invention can be configured to measure the time difference before the predetermined temperature is reached and the difference between the input temperature and the output temperature after the predetermined time, and determine whether there is GPF13 in the exhaust pipe 9 based on the measured value.

[0089] Furthermore, the separation determination device in the embodiments of the present invention can be configured to determine whether there is GPF13 in the exhaust pipe 9 based on the time change rate of the output temperature corresponding to the time change rate of the input temperature at the time point when the input temperature reaches the predetermined temperature. Figure 7 The results of verifying the relationship between the rate of change of input temperature and the rate of change of output temperature at the point when the input temperature reaches a predetermined temperature are shown. The verification results are plotted with "●", and a solid line indicates the fourth threshold used to determine whether GPF13 is present in the exhaust pipe 9. The area above this fourth threshold is the area where GPF13 is determined not to be present in the exhaust pipe 9. That is, if the rate of change of output temperature corresponding to the rate of change of input temperature is below the preset fourth threshold, it is determined that GPF13 is present in the exhaust pipe 9. Furthermore, the aforementioned predetermined temperature corresponds to the "fourth predetermined temperature" in the embodiments of the present invention, and can be set to a value different from the value used in step S6.

[0090] By using the time change rate of the output temperature corresponding to the time change rate of the input temperature at the time point when the input temperature reaches the predetermined temperature, it is possible to determine whether there is GPF13 in the exhaust pipe 9 with good accuracy, regardless of the driving mode.

Claims

1. A device for determining the separation 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 separation determination device of the exhaust purification device is characterized by having: 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 inside the housing. The controller has: The engine stop time acquisition unit acquires the time from when the engine stops to when it starts again; and The determination unit, if the time from engine stop to start is longer than a predetermined time, determines whether the exhaust purification device is installed in the housing based on the input temperature detected by the input temperature sensor and the output temperature detected by the output temperature sensor. The controller is configured as follows: Calculate the cumulative amount of exhaust gas from the start of the engine. If the cumulative amount is above a predetermined amount, the determination unit determines whether the exhaust purification device is installed inside the housing. The controller is further configured to pre-calculate a predetermined cumulative amount that, when the exhaust purification device is installed inside the housing, causes the input temperature to be above the dew point temperature of the moisture and the output temperature to become below the dew point temperature. The predetermined amount includes the predetermined cumulative amount.

Images