Exhaust control device

Abstract

To provide an exhaust control device capable of surely keeping an exhaust switch valve in an open state in starting an engine, and preventing a driver from feeling discomfort due to drive sound of a motor of an exhaust switch valve.SOLUTION: An exhaust control device includes a noise elimination passage for discharging exhaust gas of an engine to the atmospheric air via a noise eliminator and a bypass passage for discharging the exhaust gas to the atmospheric air while bypassing the noise eliminator as the passages of the exhaust gas of the engine, and further includes an exhaust gas switching valve driven by a motor to open and close the bypass passage. The exhaust control device is constituted to determine a timing when the engine starts rotation for starting, to switch the exhaust gas switching valve to an open state by the motor so that the exhaust gas is circulated to the bypass passage on the basis of the determination of the timing when the engine starts the rotation for starting, and to forbid the operation of the exhaust gas switching valve by the motor until the start of the rotation of the engine for starting is determined after output of a start command to start the engine.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an apparatus for controlling the exhaust of an internal combustion engine such as a gasoline engine, and more particularly to an exhaust control apparatus provided with a muffler provided in an exhaust path of an internal combustion engine.

Background Art

[0002] Generally, a muffler for reducing exhaust noise is attached to an exhaust path of an internal combustion engine mounted on a vehicle such as an automobile. Patent Document 1 describes a vehicle muffler device in which a volume chamber that functions as an expansion chamber or a resonance chamber is partitioned and formed inside the muffler, and a switching valve for switching the exhaust path is provided. The vehicle muffler device is said to be able to improve the exhaust performance and the output characteristics of the engine by reducing the back pressure by opening the switching valve at engine startup to increase the passage area.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, like the silencing device described in Patent Document 1, with the development of vehicle technology, the quietness provided by mufflers has been improving. However, depending on the driver, there are cases where they deliberately want to hear the exhaust sound in order to further enhance the driving feel of the vehicle or roughly check whether the engine is operating normally. Therefore, a silencing path that discharges to the atmosphere via a muffler as the exhaust path of the engine and a bypass path that bypasses the muffler and discharges to the atmosphere are provided, and an exhaust control device configured to selectively guide the exhaust to the bypass path by an exhaust switching valve that is opened and closed by a motor is conventionally known. According to this type of device, for example, if the exhaust switching valve is opened and the exhaust is allowed to flow to the bypass path side, a part of the exhaust flows without passing through the muffler, so the exhaust sound becomes louder. On the other hand, if the exhaust switching valve is closed to block the bypass path, the exhaust flows through the silencing path, so the normal silencing effect and quietness can be maintained.

[0005] Since it is desirable to be able to hear the engine sound or exhaust sound at the start of the engine, in the above-described exhaust control device, for example, the exhaust switching valve is pre-opened at the previous vehicle stop, and the exhaust at engine start is guided to the bypass path to increase the engine start sound and exhaust sound at engine start. However, there is a concern that so-called slippage may occur in which the exhaust switching valve inadvertently moves in the closed direction due to some disturbance signal or external force during vehicle stop. In such a case, if the engine is started with the exhaust switching valve not fully open, the engine start sound or exhaust sound will be smaller than expected, so there is a possibility of erroneously detecting an abnormality in the exhaust switching valve. To avoid such inconveniences, it is conceivable to open the exhaust switching valve when starting the engine. However, in that case, since the switching valve is opened before the exhaust is discharged from the engine, the operating sound of the exhaust switching valve or the motor that drives it reaches the driver prior to starting the engine, which may give the driver a sense of discomfort.

[0006] The present invention has been made paying attention to the above technical problems, and an object thereof is to provide an exhaust control device capable of surely opening an exhaust switching valve at the time of engine start and avoiding a sense of discomfort of a driver caused by a driving sound of a motor of the exhaust switching valve.

Means for Solving the Problems

[0007] In order to achieve the above object, the present invention includes a muffler path that discharges to the atmosphere via a muffler as an exhaust path of an engine, and a bypass path that bypasses the muffler and discharges to the atmosphere, and further includes an exhaust switching valve that is driven by a motor to open and close the bypass path. The exhaust control device determines a time point when the engine starts to rotate for starting, and based on the determination of the time point when the engine starts to rotate for starting, the exhaust flows through the bypass path. energize to enable the operation of the motor that switches the exhaust switching valve to the open state, After an output of a start command for starting the engine, until a time point when the engine starts to rotate for starting is determined, the motor energize to operate the is configured to be prohibited.

Effects of the Invention

[0009] According to the exhaust control device of claim 1 of the present invention, based on the fact that the engine starts to rotate for starting, the exhaust switching valve is configured to be opened, so that the driving sound of the motor of the exhaust switching valve is blocked by the rotation of the engine. Further, after an output of a start command for starting the engine, until the engine starts to rotate for starting, the operation of the exhaust switching valve by the motor is configured to be prohibited, so that there is no driving sound of the motor until the engine starts to rotate, and a sense of discomfort of a driver can be avoided. kite and the exhaust switching valve is opened. enable the energization of the motor that Since it is configured in this way, the driving sound of the motor of the exhaust switching valve is blocked by the rotation of the engine. Also, after the output of the start command for starting the engine, until the engine starts to rotate for starting, the operation of the exhaust switching valve by the motor is configured to be prohibited, so that there is no driving sound of the motor until the engine starts to rotate. noise associated with rotation Therefore, a sense of discomfort of a driver can be avoided. make Since it is configured to prohibit the operation of the exhaust switching valve by the motor until the engine starts to rotate, there is no driving sound of the motor until the engine starts to rotate. is, mo Therefore, a sense of discomfort of a driver can be avoided.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0012] The exhaust control device in an embodiment of the present invention will be specifically described with reference to the drawings. It should be noted that the embodiments described below are merely examples of implementing the present invention and do not limit the present invention.

[0013] FIG. 1 is a schematic diagram for explaining the configuration of an embodiment of the present invention. The exhaust device 1 is configured on the downstream side of an exhaust manifold (not shown) that collects exhaust discharged from each cylinder of an internal combustion engine (hereinafter referred to as an engine) not shown mounted on a vehicle. In an embodiment of the present invention, for example, it is an engine of a V-type or horizontally opposed type, and is an exhaust device of a so-called dual exhaust system type in which the exhaust path is divided into two and discharged through independent exhaust manifolds. In the exhaust pipe 2 connected via the exhaust manifold, an exhaust purification catalyst 3, a gasoline particulate filter (hereinafter referred to as GPF) 4, an exhaust switching valve 5, and a muffler 6 are provided in order from the upstream side.

[0014] The exhaust purification catalyst 3 is an exhaust purification catalyst conventionally used in vehicles, such as an oxidation catalyst that oxidizes environmental pollutants such as hydrocarbons and carbon monoxide, and a storage reduction type catalyst that captures nitrogen oxides as nitrate nitrogen and then reduces and detoxifies them.

[0015] The GPF 4 is a filter that collects PM (particulate matter) generated by burning gasoline.

[0016] The exhaust switching valve 5 is a valve that opens and closes the bypass path among the silencing path 7 that discharges to the atmosphere via the muffler 6 as an exhaust path and the bypass path 8 that bypasses the muffler 6 and discharges to the atmosphere, and an exhaust switching valve opening sensor 9 that detects the open / closed state or the opening degree thereof, and a motor (not shown) for opening and closing driving are provided.

[0017] The muffler 6 may have the same configuration as a conventionally known muffler that gradually reduces the exhaust pressure and temperature by performing expansion and resonance inside the muffler 6 in order to reduce the exhaust sound.

[0018] The configuration of the exhaust switching valve 5 will be specifically described with reference to FIG. 2. The exhaust switching valve 5 in the embodiment of the present invention is a valve that switches between two states, or a valve that can be set to an appropriate opening degree, as shown in region A "closed" and region B "open" in FIG. 2. For example, if the exhaust switching valve 5 is closed and the exhaust flows through the silencing path 7, the normal silencing effect and quietness can be maintained. On the other hand, if the exhaust switching valve 5 is open and most of the exhaust flows through the bypass path 8, the exhaust sound increases because it does not pass through the muffler 6 and can be heard.

[0019] Furthermore, an electronic control unit (hereinafter referred to as ECU) 10 for controlling the engine is provided. The ECU 10 is mainly composed of a microcomputer, a memory, etc., performs calculations using the input data and the data stored in advance, and is configured to output the result of the calculation as a control command signal.

[0020] An example of the signal input to the ECU 10 is the signal of the exhaust switching valve opening sensor 9, the signal of the engine speed detection sensor 11 that detects the engine speed, the signal of the ignition switch detection sensor 12 that detects the ON / OFF of the ignition switch (not shown), and the like.

[0021] The ECU 10 shown in FIG. 1 has at least, as a functional configuration, a function of controlling a valve opening adjustment unit 13, an engine start determination unit 14, and a motor energization prohibition unit 15.

[0022] The valve opening adjustment unit 13 has a function of adjusting the opening and closing of the exhaust switching valve 5 based on the exhaust switching valve opening sensor 9 and the engine speed detection sensor 11. For example, when the engine starts to rotate for starting at engine start, based on the signal of the engine speed detection sensor 11, it has a function of adjusting the opening and closing of the exhaust switching valve 5 by the exhaust switching valve opening sensor 9.

[0023] The engine start determination unit 14 is a functional means for determining whether or not the signal of the ignition switch detection sensor 12 is detected by a start command for starting the engine.

[0024] The motor energization prohibition unit 15 affirm with 4 has a function of prohibiting the energization of the motor that drives the exhaust switching valve 5 until it is definitely determined and until the signal of the engine speed detection sensor 11 is detected.

[0025] When starting the engine, if the driver deliberately wants to hear a louder exhaust sound, for example, if the exhaust switching valve 5 is opened in advance at the previous vehicle stop and switched to the bypass path 8, the engine start sound and the exhaust sound will increase.

[0026] However, there is a concern that so-called slippage may occur in which the exhaust switching valve 5 moves unintentionally in the closing direction due to some disturbance signal or external force during vehicle stop. If the engine is started with the exhaust switching valve 5 not fully open, the engine start sound or the exhaust sound will be beyond the assumption. small aboveTherefore, there is a possibility of erroneously detecting an abnormality in the exhaust switching valve 5. Furthermore, since the exhaust switching valve 5 will be opened before the exhaust is discharged from the engine, the operating sound of the exhaust switching valve 5 or the motor that drives it may reach the driver prior to starting the engine, which may make the driver feel uncomfortable.

[0027] In order to solve such problems, in order to surely keep the exhaust switching valve 5 open after the engine is started and avoid the driver's discomfort caused by the driving sound of the motor of the exhaust switching valve 5, the exhaust control device in the embodiment of the present invention described above is configured to execute the control described below.

[0028] FIG. 3 is a flowchart for explaining an example of the control, which is executed by the above-described ECU 10. The control shown in the flowchart of FIG. 3 is repeatedly executed from the time when the engine is started and the main relay inside the ECU 10 is turned on. In the control example shown in FIG. 3, first, it is determined whether or not the ON state of the ignition switch is detected (step S1). That is, it is determined whether or not a start command for starting the engine is output, and in this control example, the determination is made based on the engine start determination unit 14.

[0029] If the determination in this step S1 is affirmative, the energization of the motor that drives the exhaust switching valve 5 is prohibited (step S2). This is because, until the signal of the ignition switch detection sensor 12 is detected and the signal of the engine speed detection sensor 11 is detected, the energization of the motor that drives the exhaust switching valve 5 is prohibited by the motor energization prohibition unit 15, and the process proceeds to step S3. On the contrary, if the determination in this step S1 is negative, step S2 is skipped and the process proceeds to step S3.

[0030] In step S3, it is determined whether or not a predetermined time has elapsed since the instruction to the exhaust switching valve 5 was given. If it is affirmatively determined in this step S3, the energization of the motor is prohibited (step S4), and the process proceeds to step S5. On the contrary, if it is negatively determined in this step S3, step S4 is skipped and the process proceeds to step S5.

[0031] The control of this step S3 and step S4 controls the ON / OFF of the energization of the motor based on the valve operation of the exhaust switching valve 5. For example, the required time for the exhaust switching valve 5 to shift from the open state to the closed state, or the required time for it to shift from the closed state to the open state, is determined in advance as a predetermined time. When the predetermined time has elapsed after driving the exhaust switching valve 5 by a switching instruction, unnecessary motor energization is avoided by not energizing the motor.

[0032] In step S5, it is determined whether or not the engine has started to rotate at the time of engine start. taka Here, in the embodiment of the present invention, the determination that the engine has started to rotate for starting is made based on the signal of the engine speed detection sensor 11, but it is not limited to the determination based on the increase in the engine speed. For example, it can be determined based on the elapse of a predetermined time set in advance from the time of the engine start request. If it is affirmatively determined in this step S5, the exhaust switching valve 5 is set to the open state (step S6). . That is, it enables energization to the motor that opens the exhaust switching valve 5. This This is controlled by the valve opening degree adjustment unit 13, and the exhaust is sent to flow through the bypass path 8, and this routine is terminated once.

[0033] On the contrary, if it is negatively determined in this step S5, the routine shown in FIG. 3 is terminated once without performing any particular control.

[0034] Next, the time chart when the control example of FIG. 3 above is executed will be described. FIG. 4 is a diagram showing the time chart, which compares and shows the engine speed, ON / OFF of the ignition switch, ON / OFF of the main relay, opening degree of the exhaust switching valve 5, and ON / OFF of the energization of the drive motor of the exhaust switching valve 5 between the conventional case and the present invention. Note that this time chart shows the operating state of the engine from the start of the engine to during operation.

[0035] Specifically, first, a start command for starting the engine is output (at time t1), and almost simultaneously when the main relay turns ON, the ignition switch turns ON and the engine control to start starts.

[0036] Next, when the engine starts to rotate after starting (at time t2) , the mo that opens the exhaust switching valve 5 to the open state - by energizing the motor perform. Even if there is so-called slippage, etc., exhaust and keeping the exhaust switching valve 5 open, the exhaust is made to flow through the bypass path 8, thereby surely increasing the exhaust sound.

[0037] Then, when the engine reaches a certain rotational speed (at time t3), if the exhaust switching valve 5 is closed and the exhaust flows through the sound insulation path 7, the normal sound insulation effect and quietness can be maintained.

[0038] Normally, if the exhaust switching valve 5 is opened at the previous vehicle stop and switched to the bypass path 8 in advance, the engine starting sound and exhaust sound can be increased at engine start. However, there is a concern such as an unintentional slip-down of the exhaust switching valve 5 due to disturbances or external forces during vehicle stop, so conventionally, the motor of the exhaust switching valve 5 was energized at time t1. Therefore, since the motor of the exhaust switching valve 5 operates before the first explosion of the engine, that is, before the engine starts to rotate, the driver may feel discomfort from the driving sound of the motor.

[0039] Therefore, in the embodiment of the present invention, the motor is inhibited from being energized at time t1 (step S2), and the motor of the exhaust switching valve 5 is turned on after the engine starts rotating for starting. connect to the exhaust By energizing the exhaust gas switching valve 5 to open state (step S6), the exhaust gas switching valve 5 can be reliably opened after the engine is started. noise associated with rotation Since the image is blocked by the light, the driver can avoid feeling uncomfortable.

[0040] Furthermore, the system is configured to prohibit operation of the exhaust switching valve 5 by the motor from time t1 to time t2, so that the motor of the exhaust switching valve 5 is prohibited from being driven until the engine starts to rotate, which means that there is no motor driving noise, thereby avoiding any discomfort to the driver.

[0041] The present invention is not limited to the above-mentioned embodiment, and can be modified as appropriate within the scope of the object of the present invention. For example, the exhaust device 1 shown in Fig. 1 is a dual exhaust system type that uses exhaust paths from both banks of a V-type engine, but the present invention is not limited to this, and the same action and effect can be achieved with an exhaust device of a conventionally known configuration in which exhaust gas discharged from an engine is collected and circulated by a single exhaust manifold.

[0042] In addition, the engine start determination unit 14 shown in the embodiment of the present invention determines whether or not a signal from the ignition switch detection sensor 12 is detected, but is not limited thereto, and may, for example, detect a signal from a starter motor sensor of a starting device (not shown), or may detect the start of rotation of the crankshaft. In short, it is sufficient that the motor of the exhaust switching valve 5 is not operated before the first explosion of the engine, that is, before the engine starts to rotate. [Explanation of symbols]

[0044] 1 Exhaust system 2 Exhaust pipe 3. Catalyst 4 GPF 5 Exhaust switching valve 6 Muffler 7 Sound absorption path 8 Bypass path 9 Exhaust switching valve opening sensor 10 ECU 11 Engine speed detection sensor 12 Ignition switch detection sensor 13 Valve opening adjustment unit 14 Engine start determination unit 15 Motor energization prohibition unit

Claims

【Claim 1】 An exhaust control device comprising a silencing path that discharges to the atmosphere via a muffler as a path for the exhaust of an engine, and a bypass path that bypasses the muffler and discharges to the atmosphere, and further comprising an exhaust switching valve that is driven by a motor to open and close the bypass path, determining that the engine has started to rotate for starting, energizing to enable the operation of the motor that switches the exhaust switching valve to an open state so that the exhaust flows through the bypass path based on the determination that the engine has started to rotate for starting, configured to prohibit energization for operating the motor until it is determined that the engine has started to rotate for starting after an output of a start command for starting the engine. An exhaust control device characterized by the above.

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