JP2010071290A - Secondary air supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary air supply device capable of precisely detecting failure. <P>SOLUTION: An ECU (Electronic Control Unit) executes a program including a step (S202) of putting a solenoid ASV (Air Switching Valve) in an opening state while controlling so that a negative pressure ASV(1) and a negative pressure ASV(2) are a closing state and an air pump is a stopping state when the air volume GA introduced to an engine is the predetermined air volume GA(0) or more and the engine starting time water temperature TW is the predetermined water temperature TW(0) or more (YES in S200), a step (S204) of detecting pressure, a step (S206) of putting the solenoid ASV in a closing state, and a step (S402) of determining as being fixed still in an opening state when any one of the negative pressure ASV(1) and the negative pressure ASV(2) causes failure when there is pulsation in pressure detected when the solenoid ASV is put in the opening state (YES in S400). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a secondary air supply device, and more particularly to a secondary air supply device capable of detecting a failure of the secondary air supply device.

2. Description of the Related Art Conventionally, a secondary air supply device is known in which secondary air pumped from an air pump is supplied to an exhaust manifold of an engine to burn CO and HC in exhaust gas and chemically change to CO ₂ and H ₂ O. Yes.

  Japanese Patent Laying-Open No. 2003-83048 (Patent Document 1) discloses a secondary air supply device capable of determining an abnormality in a component of the secondary air supply device. A secondary air supply device described in Patent Literature 1 includes a secondary air supply passage that supplies secondary air upstream from an exhaust purification device of an exhaust system of an internal combustion engine, and an opening / closing portion that opens and closes the secondary air supply passage. , A check valve disposed downstream of the opening / closing portion, a pressure sensor disposed on the secondary air supply passage, and an abnormality of the component based on the pressure value and the pressure fluctuation value detected by the pressure sensor An anomaly detection unit. The abnormality detection unit detects clogging of the secondary air supply passage by driving the air pump at the time of opening / closing control of the opening / closing means and detecting the discharge pressure of the air pump.

  According to the secondary air supply apparatus described in this publication, the failure mode of each component can be determined in detail according to the combination by checking the pressure value and the pressure fluctuation value with the pressure sensor. Further, by detecting the decrease in the discharge pressure by driving the air pump during the closing control, it is possible to simultaneously determine the abnormality of the air pump and the clogging of the secondary air supply passage.

JP 2003-83048 A

  However, the secondary air supply device described in Japanese Patent Application Laid-Open No. 2003-83048 has a problem that it may not be possible to accurately determine an abnormality. This secondary air supply device is premised on the provision of an opening / closing portion that opens and closes the secondary air supply passage and a check valve disposed downstream of the opening / closing portion. However, no consideration is given to the secondary air supply device other than this form. Therefore, depending on the configuration of the secondary air supply device, it may be impossible to accurately determine the abnormality. Moreover, although the clogging of the secondary air supply passage is simultaneously determined by detecting the discharge pressure by driving the air pump, it may not be appropriate to drive the air pump.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a secondary air supply device that can accurately detect a failure.

  A secondary air supply device according to a first aspect of the present invention is a secondary air supply device that supplies secondary air to an upstream side of an exhaust purification device of an internal combustion engine provided with a plurality of cylinders. The secondary air supply device is connected to the first on-off valve for opening and closing the first air passage through which the air pumped from the air pump flows, and to the first air passage on the downstream side of the first on-off valve. And a second on-off valve that opens and closes a second air passage connected to an exhaust side of a predetermined cylinder among the plurality of cylinders, and a first air on the downstream side of the first on-off valve. A third on-off valve for opening and closing a third air passage connected to the passage and connected to an exhaust side of a cylinder different from the cylinder to which the second air passage is connected; an air pump; and a first on-off valve And a pressure detecting means for detecting the pressure of the first air passage, and the second on-off valve and the third on-off valve are controlled so that the first on-off valve is opened. Is controlled to be closed and the air pump is controlled to be stopped Based on the detection result of the kick pressure detection means, and a failure detection means for detecting failure in the secondary air supply apparatus.

  According to the first invention, the first air passage is opened and closed by the first on-off valve, the second air passage is opened and closed by the second on-off valve, and the third air passage is opened and closed by the third on-off valve. Is done. The pressure in the first air passage is detected by a pressure detection means provided between the air pump and the first on-off valve. The failure detection means is controlled so that the first on-off valve is opened, the second on-off valve and the third on-off valve are controlled to be closed, and the air pump is stopped. The failure of the secondary air supply device is detected based on the detection result of the pressure detection means in the case of being controlled. For example, when pressure fluctuation is detected by the pressure detection means, the exhaust gas is flowing back into the first air passage through at least one of the second air passage and the third air passage. You can say that. In this case, it is considered that at least one of the second on-off valve and the third on-off valve has failed and is stuck in the open state. Therefore, when the pressure fluctuation is detected, it is possible to detect a failure of the secondary air supply device, assuming that at least one of the second on-off valve and the third on-off valve has failed. Thereby, the failure of the second on-off valve and the third on-off valve of the secondary air supply device can be accurately detected. Therefore, it is possible to provide a secondary air supply device that can accurately detect a failure.

  In the secondary air supply apparatus according to the second invention, in addition to the configuration of the first invention, the failure detection means may provide a secondary when the amount of air introduced into the internal combustion engine is greater than a predetermined amount of air. Means for detecting a failure of the air supply device;

  According to the second invention, when the amount of air introduced into the internal combustion engine is larger than a predetermined amount of air, a failure of the secondary air supply device is detected. When the amount of air introduced is large, the amount of exhaust gas is sufficiently large. Therefore, when at least one of the second on-off valve and the third on-off valve is fixed in the open state, the amplitude of the pressure fluctuation due to the exhaust gas flowing back to the first air passage increases. As a result, when at least one of the second on-off valve and the third on-off valve is stuck in the open state, the pressure fluctuation can be detected with high accuracy by the pressure detecting means. Therefore, it is possible to improve the accuracy when detecting a failure of the secondary air supply device. As a result, a failure of the secondary air supply device can be accurately detected.

  In the secondary air supply apparatus according to the third invention, in addition to the configuration of the first or second invention, the failure detection means causes the secondary air supply apparatus to fail if a pressure fluctuation is detected by the pressure detection means. Means for detecting the presence.

  According to the third invention, when pressure fluctuation is detected by the pressure detection means, the exhaust gas is introduced into the first air passage via at least one of the second air passage and the third air passage. It can be said that it is in a reverse flow state. In this case, it is considered that at least one of the second on-off valve and the third on-off valve has failed and is stuck in the open state. Therefore, when a pressure fluctuation is detected, it is possible to detect that the secondary air supply device has failed, assuming that at least one of the second on-off valve and the third on-off valve has failed. . Thereby, the failure of the second on-off valve and the third on-off valve of the secondary air supply device can be accurately detected.

  A secondary air supply device according to a fourth aspect of the present invention is a secondary air supply device that supplies secondary air to an upstream side of an exhaust purification device of an internal combustion engine mounted on a vehicle. This secondary air supply device has pressure detecting means for detecting the pressure of air pumped from an air pump, means for detecting information related to sound felt by a vehicle occupant, When the value is larger than the predetermined value, the failure of the secondary air supply device is determined based on the detection result of the means for operating the air pump and the pressure detection means when the air pump is controlled to operate. Fault detection means for detecting.

  According to the fourth aspect of the invention, the air pump is activated when the volume of sound felt by the vehicle occupant is greater than a predetermined value. Thus, the air pump can be operated in a situation where the operating sound of the air pump is difficult to be heard by the passenger due to other sounds. Therefore, the uncomfortable feeling given to the passenger by the operating sound of the air pump can be suppressed. The pressure of the air pumped from the air pump is detected by the pressure detection means. The failure detection means detects a failure of the secondary air supply device based on the detection result of the pressure detection means when the air pump is controlled to operate. For example, when the pressure detection means does not detect an increase in pressure even though the air pressure increases due to the operation of the air pump, a failure of the pressure detection means is detected. Thereby, it is possible to detect a failure of the secondary air supply device while suppressing a sense of discomfort given to the passenger by the operating sound of the air pump. Therefore, the failure of the secondary air supply device can be accurately detected by appropriately operating the air pump. As a result, it is possible to provide a secondary air supply device that can accurately detect a failure.

  In the secondary air supply device according to the fifth aspect of the invention, in addition to the configuration of the fourth aspect of the invention, the information about the sound is at least one of the vehicle speed, the rotational speed of the internal combustion engine, and the opening of the throttle valve provided in the internal combustion engine. Or one.

  According to the fifth aspect, at least one of the vehicle speed, the rotational speed of the internal combustion engine, and the opening of a throttle valve provided in the internal combustion engine can be detected as information related to sound.

  In the secondary air supply device according to the sixth invention, in addition to the configuration of the fourth or fifth invention, the internal combustion engine is provided with a plurality of cylinders. The secondary air supply device is connected to the first on-off valve that opens and closes the first air passage through which the air pumped from the air pump flows, and to the first air passage on the downstream side of the first on-off valve, A second on-off valve that opens and closes a second air passage connected to an exhaust side of a predetermined cylinder among the plurality of cylinders, and a first air passage downstream of the first on-off valve. And a third on-off valve that opens and closes a third air passage connected to an exhaust side of a cylinder different from the cylinder to which the second air passage is connected. The failure detection means includes means for detecting a failure of the secondary air supply device based on the detection result of the pressure detection means when each on-off valve is in a closed state.

  According to the sixth invention, the first air passage is opened and closed by the first on-off valve, the second air passage is opened and closed by the second on-off valve, and the third air passage is opened and closed by the third on-off valve. Is done. The failure detection means detects a failure of the secondary air supply device based on the detection result of the pressure detection means when each on-off valve is closed. Thereby, the air pumped from the air pump can be confined and the pressure can be increased. Therefore, the failure of the secondary air supply device can be detected based on whether or not the pressure detected by the pressure detection means increases.

  In the secondary air supply apparatus according to the seventh aspect of the invention, in addition to the configuration of the sixth aspect of the invention, the failure detection means has a failure of the secondary air supply apparatus when the pressure detection means does not detect an increase in pressure. Means for detecting.

  According to the seventh aspect of the present invention, it can be said that the pressure detection means is out of order when the pressure detection means does not detect a pressure increase under the situation where the pressure of the air pumped from the air pump should increase. Therefore, when the pressure detection means does not detect a pressure increase, it can be detected that the secondary air supply device is out of order.

It is a control block diagram of the secondary air supply device concerning a 1st embodiment of the present invention. It is a flowchart which shows the control structure of the program which ECU of the secondary air supply apparatus which concerns on the 1st Embodiment of this invention performs. It is a timing chart which shows the state of the air pump controlled by ECU of the secondary air supply apparatus which concerns on the 1st Embodiment of this invention, electromagnetic ASV, negative pressure ASV (1), and negative pressure ASV (2). It is a flowchart which shows the control structure of the program which ECU of the secondary air supply apparatus which concerns on the 2nd Embodiment of this invention performs.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
With reference to FIG. 1, a vehicle equipped with a secondary air supply device according to a first embodiment of the present invention will be described. In this vehicle, an engine 100 and an ECU (Electronic Control Unit) 300 are mounted. The secondary air supply device according to the present embodiment is realized by a program executed by ECU 300, for example.

  The engine 100 is a V-type engine. The format of engine 100 is not limited to the V type. Air that has been sucked from the air cleaner 102 is introduced into the engine 100 via the intake pipe 104 and the intake manifold 106. Air is introduced from the intake manifold 106 into the combustion chambers of the eight cylinders 108 together with fuel injected from an injector (not shown). The number of cylinders 108 is not limited to eight.

  The mixture of air and fuel introduced into each cylinder 108 is ignited by an ignition plug (not shown) and burned. Thereby, engine 100 generates a driving force. The air-fuel mixture after combustion, that is, exhaust gas, is led to exhaust manifolds 110 and 112 connected to the cylinder 108, purified by the catalysts 114 and 116, and then discharged outside the vehicle. The amount of air introduced into engine 100 is controlled by throttle valve 120. The opening degree of the throttle valve 120 is controlled by the actuator 122.

When the catalysts 114 and 116 are cold, the catalysts 114 and 116 cannot sufficiently exhibit the exhaust gas purification action. Therefore, secondary air is supplied to the exhaust manifolds 110 and 112. The secondary air, CO and HC in the exhaust gas is combusted, are chemically changed to CO ₂ and H ₂ O.

  In the present embodiment, air in the engine room is used as the secondary air. An air pump 200 is provided to supply secondary air. The air pump 200 pumps the air in the engine room into the first air passage 210.

An electromagnetic ASV (Air Switching Valve) 212 is provided on the first air passage 210 downstream of the air pump 200. The electromagnetic ASV 212 selectively switches between an open state and a closed state based on a control signal transmitted from the ECU 300. Thereby, the electromagnetic ASV 212 can open and close the first air passage 210. A second air passage 220 and a third air passage 230 are connected to the first air passage 210.

  One end of the second air passage 220 is connected to the first air passage 210 downstream of the electromagnetic ASV 212. The other end of the second air passage 220 is connected to the exhaust manifold 110 connected to one bank of the engine 100. That is, the other end of second air passage 220 is connected to the exhaust side of cylinder 108 provided in one bank of engine 100.

  Similarly, one end of the third air passage 230 is connected to the first air passage 210 downstream of the electromagnetic ASV 212. The other end of the third air passage 230 is connected to the exhaust manifold 112 connected to the other bank of the engine 100. That is, the other end of the third air passage 230 is connected to the exhaust side of the cylinder 108 different from the cylinder 108 to which the second air passage 220 is connected.

  On the second air passage 220, a negative pressure ASV (1) 222 is provided. The negative pressure ASV (1) 222 is connected to a VSV (Vacuum Switching Valve) 224. Similarly, a negative pressure ASV (2) 232 is provided on the third air passage 230. The negative pressure ASV (2) 232 is connected to a VSV (Vacuum Switching Valve) 234.

  The VSVs 224 and 234 are connected to the negative pressure tank 240. The negative pressure tank 240 is connected to the intake pipe 104 via the check valve 242 on the downstream side of the throttle valve 120.

  The check valve 242 allows air flow from the negative pressure tank 240 to the intake pipe 104 and prohibits air flow from the intake pipe 104 to the negative pressure tank 240. As a result, the pressure in the negative pressure tank 240 becomes a negative pressure state.

  Based on the control signal transmitted from the ECU 300, the VSV 224 is in a state in which the negative pressure from the negative pressure tank 240 is guided to the negative pressure ASV (1) 222 and a state in which the atmospheric pressure is guided to the negative pressure ASV (1) 222. Switch. When a negative pressure from the negative pressure tank 240 is introduced to the negative pressure ASV (1) 222, the negative pressure ASV (1) 222 is in an open state. When the atmospheric pressure is introduced to the negative pressure ASV (1) 222, the negative pressure ASV (1) 222 is closed. Thus, the negative pressure ASV (1) 222 can open and close the second air passage 220.

  Similarly, the VSV 234 guides the negative pressure from the negative pressure tank 240 to the negative pressure ASV (2) 232 and the atmospheric pressure to the negative pressure ASV (2) 232 based on the control signal transmitted from the ECU 300. Switch to the state. When the negative pressure from the negative pressure tank 240 is introduced to the negative pressure ASV (2) 232, the negative pressure ASV (2) 232 is opened. When the atmospheric pressure is introduced to the negative pressure ASV (2) 232, the negative pressure ASV (2) 232 is closed. Thereby, the negative pressure ASV (2) 232 can open and close the third air passage 230.

  When the electromagnetic ASV 212, the negative pressure ASV (1) 222, and the negative pressure ASV (2) 232 are open, the air pumped by the air pump 200 is the first air passage 210, the second air passage 220, and the third air passage. The exhaust manifolds 110 and 112 are supplied to the exhaust manifolds 110 and 230. As a result, the secondary air is supplied to the exhaust side of each cylinder 108.

  ECU 300 receives signals representing detection results of air flow meter 302, throttle opening sensor 304, pressure sensor 306, vehicle speed sensor 308, crank position sensor 310, and water temperature sensor 312.

  Air flow meter 302 detects the amount of air introduced into engine 100. The throttle opening sensor 304 detects the throttle opening. The pressure sensor 306 is provided between the air pump 200 and the electromagnetic ASV 212 and detects the pressure in the first air passage 210. The vehicle speed sensor 308 detects the number of rotations of a wheel (not shown). ECU 300 detects the vehicle speed based on the number of wheel rotations detected by vehicle speed sensor 308. Crank position sensor 310 detects the rotational speed of a crankshaft (not shown) of engine 100, that is, engine rotational speed NE. Water temperature sensor 312 detects the temperature of cooling water of engine 100.

  ECU 300 executes arithmetic processing based on signals transmitted from these sensors and the like, maps and programs stored in memory 320. Thereby, ECU 300 controls the devices mounted on the vehicle so that the vehicle is in a desired state. In the present embodiment, ECU 300 detects a failure of electromagnetic ASV 212, negative pressure ASV (1) 222, and negative pressure ASV (2) 232.

  With reference to FIG. 2, a control structure of a program executed by ECU 300 of the secondary air supply device according to the present embodiment will be described.

  In step (hereinafter, step is abbreviated as S) 100, ECU 300 determines whether or not an AI (Air Injection) execution condition is satisfied. Here, AI means that the secondary air is pumped by the air pump 200 and supplied to the exhaust side of each cylinder. The AI execution conditions include conditions regarding the coolant temperature of the engine 100, the elapsed time since the engine 100 was started, the amount of air introduced into the engine 100, and the like. Since a well-known general condition may be used as the AI execution condition, further detailed description thereof will not be repeated here. If the AI execution condition is satisfied (YES in S100), the process proceeds to S102. If not (NO in S100), the process proceeds to S200.

  In S102, ECU 300 puts air pump 200 into an operating state. In S104, ECU 300 opens electromagnetic ASV 212. In S106, ECU 300 guides the negative pressure from negative pressure tank 240 to negative pressure ASV (1) 222 by VSV 224, and opens negative pressure ASV (1) 222. In S108, ECU 300 guides the negative pressure from negative pressure tank 240 to negative pressure ASV (2) 232 by VSV 234, and opens negative pressure ASV (2) 232.

  In S110, ECU 300 determines whether or not the AI end condition is satisfied. The AI end condition includes conditions relating to the elapsed time since the execution of AI, the temperature of the catalyst 116, and the like. Since a well-known general condition may be used as the AI termination condition, further detailed description thereof will not be repeated here. If the AI end condition is satisfied (YES in S110), the process proceeds to S112. If not (NO in S110), the process returns to S110.

  In S112, ECU 300 ends AI. The air pump 200 is stopped by the end of AI. The electromagnetic ASV 212, the negative pressure ASV (1) 222, and the negative pressure ASV (2) 232 are closed.

  In S114, ECU 300 detects the back pressure of air pump 200, that is, the pressure in first air passage 210, based on the signal transmitted from pressure sensor 306. In S116, ECU 300 opens electromagnetic ASV 212.

  In S118, ECU 300 detects the back pressure of air pump 200, that is, the pressure in first air passage 210, based on the signal transmitted from pressure sensor 306. In S120, ECU 300 closes electromagnetic ASV 212.

  In S200, ECU 300 determines that air amount GA introduced into engine 100 is equal to or greater than a predetermined air amount GA (0), and water temperature (cooling water temperature) TW at the time of starting engine 100 is predetermined. It is determined whether or not the temperature is equal to or higher than the water temperature TW (0).

  Here, the air amount GA (0) is a pressure fluctuation caused by exhaust gas flowing back to the first air passage 210 when the electromagnetic ASV 212, the negative pressure ASV (1) 222, and the negative pressure ASV (2) 232 are open. Is a value as detected by the pressure sensor 306. Water temperature TW (0) is a water temperature corresponding to the temperature of ECU 300 when ECU 300 is operable, for example.

  If air amount GA introduced into engine 100 is equal to or greater than GA (0) and water temperature TW at the start of engine 100 is equal to or greater than TW (0) (YES in S200), the process proceeds to S202. If not (NO in S200), this process ends. In addition to the conditions relating to the air amount GA and the water temperature TW, when other conditions are satisfied, the process may be moved to S202.

  In S202, ECU 300 performs control to stop air pump 200, and opens electromagnetic ASV 212 in a state in which negative pressure ASV (1) 222 and negative pressure ASV (2) 232 are controlled to be closed. Let

  In S204, ECU 300 detects the back pressure of air pump 200, that is, the pressure in first air passage 210, based on the signal transmitted from pressure sensor 306. In S206, ECU 300 closes electromagnetic ASV 212.

  In S300, ECU 300 causes pressure pulsation, ie, pressure fluctuation, when air pump 200 is stopped and electromagnetic ASV 212, negative pressure ASV (1) 222, and negative pressure ASV (2) 232 are all closed. Determine whether or not. If there is a pressure fluctuation (YES in S300), the process proceeds to S302. If not (NO in S300), the process proceeds to S400.

  In S302, ECU 300 causes negative pressure ASV (1) 222 and negative pressure ASV (1) 222 and negative pressure ASV (1) 222 to remain open while at least one of negative pressure ASV (1) 222 and negative pressure ASV (2) 232 fails. It is determined that at least one of the negative pressure ASV (2) 232 and the electromagnetic ASV 212 are fixed.

  In S400, ECU 300 is controlled such that air pump 200 is stopped, and negative pressure ASV (1) 222 and negative pressure ASV (2) 232 are closed, and electromagnetic ASV 212 is open. In this case, it is determined whether or not there is pressure pulsation, that is, pressure fluctuation. If there is a pressure fluctuation (YES in S400), the process proceeds to S402. If not (NO in S400), this process ends. In S402, ECU 300 determines that at least one of negative pressure ASV (1) 222 and negative pressure ASV (2) 232 has failed and is stuck in an open state.

  The operation of ECU 300 of the secondary air supply device according to the present embodiment based on the above-described structure and flowchart will be described.

  When the driver turns on an ignition switch (not shown) and starts the vehicle system, it is determined whether or not the AI execution condition is satisfied (S100). When the AI execution condition is satisfied (YES in S100), as shown in FIG. 3, air pump 200 operates at time T (1) (S102).

  After the operation of the air pump 200, the electromagnetic ASV 212 is opened at time T (2) (S104). Thereafter, the negative pressure ASV (1) 222 is opened at time T (3) (S106). Further thereafter, at time T (4), the negative pressure ASV (2) 232 is opened (S108).

  As a result, the secondary air pumped by the air pump 200 is supplied to the exhaust side of each cylinder 108 via the first air passage 210, the second air passage 220, and the third air passage 230 (AI is executed). )

  If the AI end condition is satisfied in this state (YES in S110), air pump 200 is stopped, and electromagnetic ASV 212, negative pressure ASV (1) 222, and negative pressure ASV (2) 232 are closed, and the time At T (5), the AI ends (S112).

  When the AI is finished (S112), the pressure sensor 306 detects the pressure in the first air passage 210 (S114). Thereafter, the electromagnetic ASV 212 is opened at time T (6) (S116), the pressure in the first air passage 210 is detected again (S118), and the electromagnetic ASV 212 is closed at time T (7). (S120).

  Here, when all of electromagnetic ASV 212, negative pressure ASV (1) 222, and negative pressure ASV (2) 232 are controlled to be closed, that is, from time T (5) to time T (6). In the meantime, as shown by the one-dot chain line in FIG. 7, if there is a pressure pulsation (pressure fluctuation), it can be said that the exhaust gas is flowing backward in the first air passage 210.

  In this case, it is considered that at least one of the negative pressure ASV (1) 222 and the negative pressure ASV (2) 232 and the electromagnetic ASV 212 are fixed in an open state. Therefore, if there is a pressure fluctuation (YES in S300), it is determined that at least one of negative pressure ASV (1) 222 and negative pressure ASV (2) 232 and electromagnetic ASV 212 are out of order ( S302).

  Further, even if there is no pressure fluctuation between time T (5) and time T (6) (NO in S300), air pump 200 is controlled to stop, and negative pressure ASV (1) 222 and negative pressure are controlled. When the ASV (2) 232 is controlled to be in the closed state and the electromagnetic ASV 212 is in the open state, that is, between the time T (6) and the time T (7), the pressure as shown by the one-dot chain line in FIG. If there is a fluctuation, it can be said that the exhaust gas is flowing backward in the first air passage 210.

  In this case, since at least one of the negative pressure ASV (1) 222 and the negative pressure ASV (2) 232 is fixed in the open state, at least one of the second air passage 220 and the third air passage 230 is used. It is thought that the exhaust gas flowed back through.

  Therefore, when there is a pressure fluctuation (YES in S400), it is determined that at least one of negative pressure ASV (1) 222 and negative pressure ASV (2) 232 has failed (S402).

  On the other hand, even when the AI execution condition is not satisfied (S100), the air amount GA introduced into the engine 100 is greater than or equal to GA (0) and the starting water temperature TW is greater than or equal to TW (0) (S200). At YES), failure determination of negative pressure ASV (1) 222 and negative pressure ASV (2) 232 is performed.

  In order to make a failure determination of the negative pressure ASV (1) 222 and the negative pressure ASV (2) 232, the AI is not executed, that is, the air pump 200 is controlled to stop, and the negative pressure ASV (1) 222 and The electromagnetic ASV 212 is opened in a state where the negative pressure ASV (2) 232 is controlled to be closed (S202).

  In this state, the pressure sensor 306 detects the pressure in the first air passage 210 (S204), and the electromagnetic ASV 212 is closed (S206). If there is a pressure fluctuation between the time when the electromagnetic ASV 212 is opened and the time when the electromagnetic ASV 212 is closed, it can be said that the exhaust gas is flowing back in the first air passage 210.

  In this case, since at least one of the negative pressure ASV (1) 222 and the negative pressure ASV (2) 232 is fixed in the open state, at least one of the second air passage 220 and the third air passage 230 is used. It is thought that the exhaust gas flowed back through.

  Therefore, when there is a pressure fluctuation (YES in S400), it is determined that at least one of negative pressure ASV (1) 222 and negative pressure ASV (2) 232 has failed (S402).

  At this time, the air amount GA introduced into the engine 100 is equal to or greater than GA (0). Therefore, the amount of exhaust gas becomes sufficiently large, and the amplitude of the pressure fluctuation detected by the pressure sensor 306 increases. Therefore, the pressure sensor 306 can detect the pressure fluctuation with high accuracy, and can detect the failure of the negative pressure ASV (1) 222 and the negative pressure ASV (2) 232 with high accuracy.

  As described above, the ECU of the secondary air supply device according to the present embodiment opens the electromagnetic ASV when the air amount GA sucked into the engine is equal to or larger than the predetermined air amount GA (0). Let At this time, the air pump is controlled to stop, and the negative pressure ASV (1) and the negative pressure ASV (2) are controlled to be closed. In this state, when pressure fluctuation is detected by the pressure sensor, the ECU determines that at least one of the negative pressure ASV (1) and the negative pressure ASV (2) has failed and is stuck in the open state. To do. Thereby, in the secondary air supply device provided with the negative pressure ASV (1) and the negative pressure ASV (2) instead of the check valve, a failure of the negative pressure ASV (1) and the negative pressure ASV (2) is detected. can do.

<Second Embodiment>
A second embodiment of the present invention will be described with reference to FIG. In the first embodiment described above, the ECU detects a failure in the electromagnetic ASV, the negative pressure ASV (1), and the negative pressure ASV (2). In the present embodiment, the ECU detects the pressure sensor. Detects faults. Other structures are the same as those in the first embodiment. The function about them is the same. Therefore, detailed description thereof will not be repeated here.

  With reference to FIG. 4, a control structure of a program executed by ECU 300 of the secondary air supply device according to the present embodiment will be described. ECU 300 executes a program described below in addition to the program in the first embodiment described above.

  In S500, ECU 300 determines whether or not AI is inactive. Here, when the AI is not operating means a state in which the AI execution condition described above is not satisfied. If the AI is not operating (YES in S500), the process proceeds to S502. If not (NO in S500), this process ends.

  In S502, ECU 300 has vehicle speed V equal to or higher than predetermined vehicle speed V (0), engine speed NE is equal to or higher than predetermined speed NE (0), and throttle opening TH is determined in advance. It is determined whether or not the opening degree TH (0) is equal to or greater than. If vehicle speed V is equal to or higher than V (0), engine speed NE is equal to or higher than NE (0), and throttle opening TH is equal to or higher than TH (0) (YES in S502), the process proceeds to S504. It is. If not (NO in S502), this process ends.

The vehicle speed V is at least one of V (0), the engine speed NE is at least NE (0), and the condition that the throttle opening TH is at least TH (0). If the condition is satisfied, the process may be moved to S504.

  In S504, ECU 300 operates air pump 200. In S506, ECU 300 detects the back pressure of air pump 200, that is, the pressure in first air passage 210, based on the signal transmitted from pressure sensor 306.

  In S508, ECU 300 determines whether or not the pressure detected by pressure sensor 306 has increased. If the pressure has increased (YES in S508), the process proceeds to S510. If not (NO in S512), the process proceeds to S512.

  In S510, ECU 300 determines that pressure sensor 306 is normal. In S512, ECU 300 determines that pressure sensor 306 has failed. At this time, the failure of the pressure sensor 306 means a failure of at least one of the pressure sensor 306 and the air pump 200.

  An operation of ECU 300 according to the present embodiment based on the above-described structure and flowchart will be described.

  If the AI execution condition is not satisfied and the AI is not operating during start-up of the vehicle system (YES in S500), the vehicle speed V is equal to or higher than V (0), and the engine speed NE is NE ( 0) or more, and it is determined whether the throttle opening TH is more than TH (0).

  When vehicle speed V is equal to or higher than V (0), engine speed NE is equal to or higher than NE (0), and throttle opening TH is equal to or higher than TH (0) (YES in S502), air pump 200 is activated. (S504).

  When the AI is not operating, that is, when the air pump 200 is operated when the electromagnetic ASV 212, the negative pressure ASV (1) 222, and the negative pressure ASV (2) 232 are closed, the air pumped from the air pump 200 Is confined in the first air passage 210. Therefore, the operation sound of the air pump 200 increases. Therefore, there is a possibility that the passenger feels uncomfortable due to the operating sound of the air pump 200.

  However, when the vehicle speed V is equal to or higher than V (0), the engine speed NE is equal to or higher than NE (0), and the throttle opening TH is equal to or higher than TH (0), road noise and engine 100 operating noise are detected. In addition, it can be said that the exhaust sound (collectively referred to as noise) is loud. When the air pump 200 is operated in such a case, it is difficult for the passenger to hear the operation sound of the air pump 200 due to these noises, so that a sense of discomfort can be suppressed.

  When the air pump 200 is activated (S504), the pressure in the first air passage 210 is detected (S506). When the air pump 200 is operated, air is pumped, so that the pressure in the first air passage 210 increases. For this reason, if the pressure sensor 306 is normal, the pressure detected by the pressure sensor 306 increases.

  Therefore, when the pressure increases (YES in S508), it is determined that pressure sensor 306 is normal (S510). On the other hand, if the pressure does not increase (NO in S508), it is determined that pressure sensor 306 has failed.

  As described above, in the present embodiment, vehicle speed V is equal to or higher than V (0), engine speed NE is equal to or higher than NE (0), and throttle opening TH is equal to or higher than TH (0). Then, the air pump is operated to detect the failure of the pressure sensor. Thereby, the operating sound of the air pump is drowned out by road noise, engine operating sound and exhaust noise, and the uncomfortable feeling given to the passenger can be suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  100 Engine, 102 Air Cleaner, 104 Intake Pipe, 106 Intake Manifold, 108 Cylinder, 110, 112 Exhaust Manifold, 114, 116 Catalyst, 120 Throttle Valve, 122 Actuator, 200 Air Pump, 210 First Air Passage, 212 Electromagnetic ASV, 220 First 2 Air passage, 222, 232 Negative pressure ASV, 224, 234 VSV, 230 3rd air passage, 240 Negative pressure tank, 242 Check valve, 302 Air flow meter, 304 Throttle opening sensor, 306 Pressure sensor, 308 Vehicle speed sensor, 310 Crank position sensor, 312 Water temperature sensor, 320 memory.

Claims (4)

A secondary air supply device that supplies secondary air to an upstream side of an exhaust gas purification device of an internal combustion engine mounted on a vehicle,
Pressure detecting means for detecting the pressure of air pumped from the air pump;
Means for detecting information relating to sound felt by a passenger of the vehicle;
Means for operating the air pump if the loudness is greater than a predetermined value;
A secondary air supply device including failure detection means for detecting a failure of the secondary air supply device based on a detection result of the pressure detection means when the air pump is controlled to operate. .   2. The secondary air supply device according to claim 1, wherein the information related to the sound is at least one of a vehicle speed, a rotation speed of the internal combustion engine, and an opening of a throttle valve provided in the internal combustion engine. The internal combustion engine is provided with a plurality of cylinders,
The secondary air supply device includes:
A first on-off valve that opens and closes a first air passage through which air pumped from the air pump flows;
A second air passage connected to the first air passage on the downstream side of the first on-off valve and opening and closing a second air passage connected to an exhaust side of a predetermined cylinder among the plurality of cylinders. Two on-off valves;
A third air passage connected to the first air passage downstream of the first on-off valve and connected to an exhaust side of a cylinder different from the cylinder to which the second air passage is connected; A third on-off valve that opens and closes;
The failure detection means includes means for detecting a failure of the secondary air supply device based on a detection result of the pressure detection means when each of the on-off valves is in a closed state. The secondary air supply device according to 2.   4. The secondary air supply device according to claim 3, wherein the failure detection means includes means for detecting that the secondary air supply device has failed when the pressure detection means does not detect a pressure increase. .

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