Vehicle control device

Abstract

To provide a vehicle control device that can enhance the accuracy in detecting removal of a filter.SOLUTION: A vehicle control device controls a vehicle that has an internal combustion engine, a filter, an electrically-heated catalyst, a first temperature sensor, and a second temperature sensor, in which in an exhaust passage of the internal combustion engine, the electrically-heated catalyst, the first temperature sensor, the filter, and the second temperature sensor are provided from an upstream side to a downstream side. The control device is equipped with an energization control unit that controls electric power supply to the electrically-heated catalyst, and a detection unit that detects whether or not the filter is removed on the basis of a first temperature detected by the first temperature sensor and a second temperature detected by the second temperature sensor, and when the detection unit performs detection, the energization control unit supplies electric power to the electrically-heated catalyst.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a control device for a vehicle.

Background Art

[0002] Exhaust gas from an internal combustion engine contains particulate matter (PM). A filter for collecting PM is provided in the exhaust passage (see Patent Document 1, etc.).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The filter may be removed from the exhaust passage. Based on the temperature of the exhaust gas, it is possible to detect whether the filter is attached or removed. However, the detection accuracy was not sufficient. Accordingly, an object is to provide a control device for a vehicle capable of improving the detection accuracy of filter removal.

Means for Solving the Problems

[0005] The above object is achieved by a vehicle control device that controls a vehicle having an internal combustion engine, a filter, an electrically heated catalyst, a first temperature sensor, and a second temperature sensor. In the exhaust passage of the internal combustion engine, the electrically heated catalyst, the first temperature sensor, the filter, and the second temperature sensor are provided in this order from the upstream side to the downstream side. The control device includes an energization control unit that controls energization of the electrically heated catalyst, and a detection unit that detects whether or not the filter has been removed based on a first temperature that is the temperature detected by the first temperature sensor and a second temperature that is the temperature detected by the second temperature sensor. When the detection unit performs detection, it can be achieved by a vehicle control device in which the energization control unit energizes the electrically heated catalyst.

[0006] When the difference between the first temperature and the second temperature is equal to or greater than a predetermined value, the detection unit determines that the filter has not been removed. When the difference between the first temperature and the second temperature is less than the predetermined value, the detection unit may determine that the filter has been removed.

[0007] The detection unit may perform the detection after a predetermined time has elapsed since the energization control unit starts energization of the electrically heated catalyst.

[0008] When the internal combustion engine is started, the energization control unit may perform the energization, and the detection unit may perform the detection after the predetermined time has elapsed since the start of the energization.

[0009] The energization control unit may control the energy input to the electrically heated catalyst.

Advantages of the Invention

[0010] A vehicle control device capable of improving the detection accuracy of filter removal can be provided.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, the vehicle control device according to the present embodiment will be described with reference to the drawings. However, in the drawings, the dimensions, ratios, etc. of each part may not be illustrated so as to exactly match the actual ones. Also, depending on the drawings, details may be omitted.

[0013] FIG. 1 is a diagram illustrating a vehicle 100 according to the embodiment. The vehicle 100 includes an internal combustion engine 10, an exhaust gas purification device 20, and an ECU (Electronic Control Unit) 40.

[0014] The internal combustion engine 10 burns fuel such as gasoline, for example, to generate power. The water temperature sensor 36 detects the temperature of the cooling water of the internal combustion engine 10. An intake passage 12 and an exhaust passage 14 are connected to the internal combustion engine 10. Air flows through the intake passage 12 and is introduced into the internal combustion engine 10. A throttle valve 16 and an air flow meter 18 are provided in the intake passage 12 and are arranged in this order from the upstream side. When the opening degree of the throttle valve 16 increases, the air flow rate in the intake passage 12 increases. When the opening degree decreases, the air flow rate decreases. The air flow meter 18 detects the air flow rate.

[0015] The exhaust gas purification device 20 includes an electrically heated catalyst 26 and a GPF (Gasoline Particulate Filter) 24 (filter) and purifies the exhaust gas of the internal combustion engine. In the exhaust passage 14, an electrically heated catalyst 26, a temperature sensor 15 (first temperature sensor), a GPF 24, and a temperature sensor 17 (second temperature sensor) are provided from the upstream side to the downstream side.

[0016] The electric heating type catalyst 26 includes a heater 21 and a catalyst 22. The heater 21 is located upstream of the catalyst 22. The heater 21 and the catalyst 22 are integrated on the same carrier. The catalyst 22 is, for example, a three-way catalyst and purifies substances such as carbon monoxide (CO) and nitrogen oxides (NOx). The heater 21 contains metal and has higher conductivity than the wall of the exhaust passage 14. The heater 21 may be, for example, a catalyst having a heater function. That is, the heater 21 may have only the function of heating, or may have both the functions of heating and exhaust purification.

[0017] The power source 30 includes, for example, a battery and a current-voltage source. The power source 30 is electrically connected to the heater 21. A current sensor 32 and a voltage sensor 34 are provided in the wiring connecting the power source 30 and the heater 21. The current sensor 32 is connected in series with the heater 21 and detects the current flowing through the heater 21. The voltage sensor 34 is connected in parallel with the heater 21 and detects the voltage applied to the heater 21.

[0018] The heater 21 generates heat when energized. The heat of the heater 21 is transferred to the catalyst 22, and the temperature of the catalyst 22 rises. The catalyst 22 is activated by the temperature rise, and the purification rate increases. The GPF 24 collects PM in the exhaust gas.

[0019] The temperature sensor 15 detects the temperature of the exhaust gas (the first temperature) between the electric heating type catalyst 26 and the GPF 24. The temperature sensor 17 detects the exhaust gas temperature (the second temperature) downstream of the filter 24.

[0020] The exhaust gas before flowing into the GPF 24 flows through the temperature sensor 15. The exhaust gas after passing through the GPF 24 flows through the temperature sensor 17. A part of the heat of the exhaust gas is taken away by the GPF 24. For this reason, generally, the temperature detected by the temperature sensor 17 is lower than the temperature detected by the temperature sensor 15. A temperature difference occurs between the two temperature sensors. When the GPF 24 is removed, the heat of the exhaust gas is not absorbed by the GPF 24. Therefore, the temperature difference between the two temperature sensors becomes smaller.

[0021] The ECU 40 is a vehicle control device that includes a storage device such as a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory), and is a control device that performs various controls by executing programs stored in the ROM and the storage device.

[0022] The ECU 40 controls the opening degree of the throttle valve 16. The ECU 40 acquires the air flow rate (intake air amount) from the air flow meter 18 and estimates the exhaust flow rate based on the intake air amount. The ECU 40 acquires the temperature detected by the temperature sensor 15, the temperature detected by the temperature sensor 17, and the water temperature detected by the water temperature sensor 36.

[0023] The ECU 40 functions as an energization control unit 42 and a detection unit 44. The energization control unit 42 controls the on / off of energization to the electric heating catalyst 26, the energization time, and the energy input to the electric heating catalyst 26. The energization control unit 42 acquires the current detected by the current sensor 32 and the voltage detected by the voltage sensor 34. The energization control unit 42 controls the electric power input from the power source 30 to the heater 21 and controls the heat generation amount of the heater 21. For example, the energization control unit 42 controls the electric power so that the electric heating catalyst 26 reaches an appropriate temperature.

[0024] The detection unit 44 acquires the difference (temperature difference dT) between the temperature detected by the temperature sensor 15 and the temperature detected by the temperature sensor 17, and detects whether the GPF 24 has been removed from the exhaust passage 14 based on the temperature difference dT.

[0025] Figures 2 and 3 are flowcharts illustrating the processes executed by the ECU 40. As shown in Figure 2, the ECU 40 determines whether to perform the removal detection of the GPF 24 (step S10). For example, immediately after performing the removal detection, if the temperature sensor has failed, etc., a negative determination (No) is made and the process ends. If the conditions for the removal detection are satisfied, it is an affirmative determination (Yes). For example, conditions include that a predetermined time has elapsed since the previous removal detection, the temperature sensor is normal, and the temperature such as the water temperature is within an appropriate range. The removal detection may be performed immediately after the start of the internal combustion engine 10.

[0026] In the case of an affirmative determination in step S10, the energization control unit 42 energizes the heater 21 of the electric heating type catalyst 26 (step S12). The detection unit 44 performs the removal detection of the GPF 24 (step S14).

[0027] Figure 3 is a flowchart illustrating the removal detection. The detection unit 44 determines whether a predetermined time has elapsed since the start of energization (step S20). In the case of a negative determination, step S20 is repeated until the time elapses. In the case of an affirmative determination, the detection unit 44 acquires the difference (temperature difference dT) between the temperature detected by the temperature sensor 15 and the temperature detected by the temperature sensor 17 (step S22). The detection unit 44 determines whether the temperature difference dT is equal to or greater than a predetermined value dTth (step S24).

[0028] When the temperature difference dT is equal to or greater than the threshold value dTth, an affirmative determination is made in step S24. The detection unit 44 determines that the GPF 24 has not been removed (step S26). When the temperature difference dT is less than the threshold value dTth, a negative determination is made in step S24. The detection unit 44 determines that the GPF 24 has been removed (step S28). After step S26 or S28, the process of Figure 3 ends.

[0029] As shown in FIG. 2, the energization control unit 42 determines whether or not the removal detection has been completed (step S16). In the case of a negative determination, step S16 is repeated. In the case of an affirmative determination, the energization control unit 42 ends the energization (step S18). The processing ends here.

[0030] FIG. 4 is a diagram illustrating a time chart. From the top, it shows the operating status of the internal combustion engine 10, the exhaust temperature, and the energization status of the electric heating type catalyst 26.

[0031] At time t1, the internal combustion engine 10 turns off from on. The energization control unit 42 turns on the energization to the electric heating type catalyst 26 and performs energization from time t1 to t2 (step S12 in FIG. 2). The detection unit 44 waits until time elapses (step S20 in FIG. 3). The detection unit 44 acquires the exhaust temperature at time t2 and calculates the temperature difference dT (step S22).

[0032] Four types of temperatures are shown as the exhaust temperature in FIG. 4. The solid line is the temperature detected by the temperature sensor 15. The thin solid line is the temperature when the electric heating type catalyst 26 is not energized. The thick solid line is the temperature when energized. The broken line is the temperature detected by the temperature sensor 17. The thin broken line is the temperature when not energized. The thick broken line is the temperature when energized. In the example of FIG. 4, the GPF 24 is attached to the exhaust passage 14.

[0033] Even when not energized, the temperature rises due to the heat of the exhaust. When energized, heat is also generated from the heater 21, so the temperature rises to a higher value.

[0034] The detection unit 44 calculates the temperature difference dT from the temperature at time t2. When not energized, the temperature detected by the temperature sensor 15 is T1a. The temperature detected by the temperature sensor 17 is T2a. When energized, the temperature detected by the temperature sensor 15 is T1b. The temperature detected by the temperature sensor 17 is T2b. The temperature T1b is higher than the temperature T1a. The temperature T2b is higher than the temperature T2a and lower than the temperature T1a.

[0035] The detection unit 44 calculates the difference between the temperature T1b and the temperature T2b, and sets the difference as the temperature difference dT. The detection unit 44 compares the temperature difference dT with a predetermined value dTth to detect the removal of the GPF 24 (step S24).

[0036] As shown by the thin line in FIG. 4, a difference also occurs between the temperature T1a and the temperature T2a. However, the temperature difference is smaller than that in the example of the thick line. For example, the temperature difference varies depending on how the exhaust hits the temperature sensor and the presence of condensed water. When the exhaust hardly hits the temperature sensor 15 and hits the temperature sensor 17 more, the detected value T1a of the temperature sensor 15 becomes lower and the detected value T2a of the temperature sensor 17 becomes higher. The temperature difference becomes smaller. Moisture in the exhaust may condense to generate condensed water. When the temperature sensor 15 comes into contact with the condensed water, the temperature T1a becomes lower and the temperature difference becomes smaller. The reduction in the temperature difference may reduce the accuracy of the removal detection.

[0037] According to the present embodiment, the detection unit 44 detects the removal of the GPF 24 based on the temperatures detected by the temperature sensor 15 and the temperature sensor 17. When performing the removal detection, the energization control unit 42 energizes the heater 21 of the electric heating catalyst 26. The exhaust heated by the heater 21 flows to the temperature sensor 15 and the temperature sensor 17. Compared with the case where no energization is performed, the temperature difference dT between the two temperature sensors when energized becomes larger. The increase in the temperature difference dT improves the accuracy of the removal detection.

[0038] When the temperature difference dT is equal to or greater than the predetermined value dTth, the detection unit 44 determines that the GPF 24 has not been removed (step S26). When the temperature difference dT is less than the predetermined value dTth, the detection unit 44 determines that the GPF 24 has been removed (step S28). In order to improve the accuracy of the removal detection, it is important that the temperature difference dT changes depending on the presence or absence of the GPF 24.

[0039] The exhaust gas is heated upstream of the GPF 24 by the electric heating type catalyst 26. The temperature T1b detected by the temperature sensor 15 increases. When the GPF 24 is installed, the GPF 24 absorbs part of the heat of the exhaust gas. The temperature of the exhaust gas flowing downstream of the GPF 24 is suppressed. The temperature T2b detected by the temperature sensor 17 becomes lower than T1b. The temperature difference dT becomes larger. When the GPF 24 is removed, heat exchange by the GPF 24 does not occur, and the exhaust gas heated by the heater 21 flows to the temperature sensor 15 and the temperature sensor 17. The temperature difference dT becomes smaller. For this reason, the accuracy of removal detection is improved.

[0040] The detection unit 44 calculates the temperature difference dT from the temperature after a predetermined time has elapsed since the energization of the electric heating type catalyst 26 was started, and performs removal detection. As shown in FIG. 4, the exhaust gas temperature after an appropriate time has elapsed since the start of energization is higher than the exhaust gas temperature immediately after the start of energization. In particular, the temperature T1b detected by the temperature sensor 15 rises significantly. The temperature difference dT expands, and the accuracy of removal detection is improved.

[0041] The GPF 24 may be removed or replaced while the internal combustion engine 10 is stopped. Also, while the internal combustion engine 10 is stopped, the temperature of the vehicle decreases. For example, at cold start, since the temperature of the exhaust passage 14 is low, condensed water is likely to be generated in the exhaust passage 14. There is a high possibility that the temperature sensor will be wetted. As shown in FIG. 4, immediately after the start of the internal combustion engine 10, the electric heating type catalyst 26 may be energized and removal detection may be performed. The GPF 24 can be detected effectively.

[0042] The energization control unit 42 controls the energy input to the heater 21 of the electric heating type catalyst 26. The energization control unit 42 may control, for example, the voltage and current, adjust the input power to the heater 21, or adjust the energization time. The temperature of the exhaust gas can be controlled.

[0043] As described above, when condensed water is generated, the accuracy of removal detection tends to decrease. For example, when the water temperature detected by the water temperature sensor 36 is around 0°C, the energization control unit 42 increases the energy. The accuracy of removal detection becomes higher. When the water temperature is high, it is considered that the outside air temperature is high and the GPF 24 is also at a high temperature. The GPF 24 is difficult to be heated by the exhaust gas, and a temperature difference is unlikely to occur. The energization control unit 42 increases the energy. The temperature difference dT expands, and the accuracy of removal detection becomes higher.

[0044] Since the exhaust gas is heated using the heater 21 of the electric heating type catalyst 26, it is not necessary to provide a new heater. An increase in cost is suppressed. The object of removal detection may be a filter that collects PM.

[0045] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

Explanation of Reference Numerals

[0046] 10 Internal combustion engine, 12 Intake passage, 14 Exhaust passage, 15, 17 Temperature sensor, 16 Throttle valve, 18 Airflow meter, 20 Exhaust gas purification device, 21 Heater, 22 Catalyst, 24 GPF, 26 Electric heating type catalyst, 30 Power source, 32 Current sensor, 34 Voltage sensor, 36 Water temperature sensor, 40 ECU, 42 Energization control unit, 44 Detection unit, 100 Vehicle

Claims

1. A vehicle control device for controlling a vehicle having an internal combustion engine, a filter, an electrically heated catalyst, a first temperature sensor, and a second temperature sensor, wherein the electrically heated catalyst, the first temperature sensor, the filter, and the second temperature sensor are provided in the exhaust passage of the internal combustion engine in this order from upstream to downstream, the control device includes: an energization control unit that controls energization to the electrically heated catalyst, a detection unit that detects whether or not the filter has been removed based on a first temperature that is the temperature detected by the first temperature sensor and a second temperature that is the temperature detected by the second temperature sensor; and when the detection unit performs detection, the energization control unit energizes the electrically heated catalyst.

2. When the difference between the first temperature and the second temperature is equal to or greater than a predetermined value, the detection unit determines that the filter has not been removed, and when the difference between the first temperature and the second temperature is less than the predetermined value, the detection unit determines that the filter has been removed. The vehicle control device according to claim 1.

3. The vehicle control device according to claim 1 or 2, wherein the detection unit performs the detection after a predetermined time has elapsed since the energization control unit starts energization to the electrically heated catalyst.

4. The vehicle control device according to claim 3, wherein the energization control unit performs the energization when the internal combustion engine is started, and the detection unit performs the detection after the predetermined time has elapsed since the start of the energization.

5. The vehicle control device according to claim 1 or 2, wherein the energization control unit controls the energy input to the electrically heated catalyst.

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