JP6911503B2 - Valve device - Google Patents

Description

The present disclosure relates to a valve device that opens and closes an exhaust gas recirculation path in EGR by a valve body.

As is well known, the exhaust gas recirculation system (hereinafter referred to as EGR) is for mixing a part of the exhaust gas generated in the internal combustion engine mounted on the transportation equipment or the like with the intake air to the internal combustion engine through the exhaust gas recirculation path. It is a device. Here, the exhaust return path is provided with a valve device capable of adjusting the opening degree of the exhaust return path.

The valve device includes a valve body provided in the exhaust return passage and a seat on which the seat is seated when fully closed.

The valve device further includes a motor that generates a driving force for driving the valve body, a control unit that outputs a control signal having a desired duty ratio, and a constant output control signal of the control unit, which is supplied from a power supply circuit. It includes a switching element that switches the voltage and applies it to the motor.

Japanese Unexamined Patent Publication No. 2003-293862

As described above, since the motor vibrates due to pulse drive, when the valve body is fully closed (or when the valve body is slightly open), the vibration of the motor is transmitted to the valve body, etc., causing abnormal noise (contact noise). Occurs. In particular, if the abnormal noise is generated before the start of the internal combustion engine, it may be heard by the passengers of the transportation equipment.

It is an object of the present disclosure to provide a valve device capable of preventing the generation of abnormal noise.

One form of the present disclosure is a valve device used in an EGR that mixes a part of exhaust gas generated in an internal combustion engine with intake air to the internal combustion engine via an exhaust gas recirculation path. A valve body that can be opened and closed, and a valve body that sits on a seat provided in the exhaust gas recirculation path when fully closed, and a motor that generates a driving force for the valve body when a pulse signal is supplied from the outside. When the input signal input when the ignition switch is other than OFF is determined to be before the start of the internal combustion engine without indicating the START position, (1) the motor has a predetermined duty ratio. The pulse signal is directed toward a valve device in which a driving force is generated so as to open the valve body at an opening degree at which the valve body does not abut on the seat, or (2) the supply of the pulse signal to the motor is stopped. Be done.

According to one form of the present disclosure, it is possible to provide a valve device capable of preventing the generation of abnormal noise.

Schematic diagram showing the configuration of the EGR of the present disclosure and its control device. Schematic diagram of the valve body and seat of FIG. 1 when viewed from the extending direction (y-axis direction) of the rotation axis of the valve body. A flow chart showing a processing procedure of the control device of FIG.

Hereinafter, the valve device 7 according to the embodiment of the present disclosure will be described in detail with reference to the above drawings.

<1. Definition>
Table 1 below shows the meanings of acronyms and abbreviations used in this embodiment.

Further, in FIGS. 1 and 2, the x-axis indicates the flow direction of the exhaust gas in the vicinity of the valve body 71 in the exhaust return passage 5. Further, the y-axis indicates a direction in which the rotation axis of the valve body 71 extends.

<2. Embodiment>
<2-1. EGR system / valve device configuration>
In FIGS. 1 and 2, the EGR system 1 is mounted on a transportation device (for example, a vehicle), and a part of the exhaust gas generated by the internal combustion engine 3 of the transportation device is sucked into the internal combustion engine 3 through the exhaust gas recirculation path 5. It is a system that reduces NOx in exhaust gas by mixing with air.

The EGR system 1 includes a cooled EGR, a hot EGR, and the like, and the following valve device 7 can be applied to any EGR. Further, in the case of cooled EGR, a cooler (not shown) for cooling the exhaust gas is provided in the middle of the exhaust gas recirculation path 5.

The valve device 7 includes at least a valve body 71, a seat 73, and a motor 75 in order to adjust the exhaust gas flow rate in the exhaust gas return path 5.

Further, in order to supply a pulse signal (pulse voltage) to the motor 75, an ECU 77 and a switching element 79 are provided externally to the valve device 7.

The ECU 77 and the switching element 79 may be built in the valve device 7.

In the example of FIG. 1, the valve body 71 is a valve disc (butterfly valve), and is connected to the rotating shaft of the motor 75 directly or via a gear or the like. As a result, the valve body 71 opens and closes the exhaust return path 5 by rotating around the axis in the valve box forming a part of the exhaust return path 5 in response to the rotation of the motor 75, thereby causing the exhaust return. The flow rate of exhaust gas passing through the road 5 is controlled.

The valve body 71 may also be a poppet valve or the like.

The seat 73 is provided on the inner peripheral surface of the valve box and holds the valve body 71 when the valve body 71 is fully closed (when seated) so that the exhaust gas does not leak to the intake flow path of the internal combustion engine 3.

The motor 75 is, for example, a DC motor, and when a pulse signal generated by a switching element 79 described later is applied, a driving force for rotationally driving the valve body 71 around an axis is generated. That is, the on / off of the motor 75 is pulse-controlled.

The ECU 77 is an example of a control unit, and includes an input / output connector, a microcomputer, a program memory, and a main memory mounted on a control board.

The input / output connector is electrically connected to an ignition switch (which may be a push switch), a motor 75, or the like (not shown).

The microcomputer executes the program in the program memory using the main memory. As a result, the microcomputer generates a pulse-shaped control signal having a predetermined duty ratio based on the input signal from the ignition switch, and outputs the pulse-shaped control signal from the input / output connector to the motor 75.

The switching element 79 is, for example, a power transistor. The switching element 79 switches the constant voltage output from the battery 711 with the control signal output from the ECU 77. The pulse voltage thus obtained is applied to the motor 75.

<2-2. Ignition switch signal>
First, the signal from the ignition switch will be described. In the present disclosure, an ignition switch having three types of positions, ACC, ON, and START, in addition to LOCK (OFF) is illustrated.

When the ignition switch is located at ACC or ON, the ignition switch outputs a signal indicating these positions. Further, while the ignition switch is ACC or ON, the electric system of the transportation equipment is turned on and the electrical components can be used, but the internal combustion engine 3 does not start.

On the other hand, when the ignition switch is located at the START, a signal indicating the START position is output from the ignition switch, the electrical components can be continuously used, and the internal combustion engine 3 is started.

<2-3. ECU (control unit) processing>
Next, the processing of the ECU 77 will be described with reference to FIG.

First, when the ECU 77 receives the signal from the ignition switch (YES in step S001), the ECU 77 determines whether or not the received signal indicates the START position (step S003).

If it is determined to be NO, the ECU 77 _{generates a control signal indicating a predetermined duty ratio D 0} (however, D ₀ > 0) and outputs the control signal to the switching element 79 (step S005).

Result of step S005, the constant voltage output from the battery 711, the switching element 79 is switched at a duty ratio _{D 0.} As a result, _{a pulse signal (pulse voltage) having a duty ratio D 0} is generated and applied to the motor 75.

The motor 75 starts to rotate in response to the supply of the pulse signal, and opens the valve body 71 with an opening degree θ _{0 defined by the duty ratio D 0.} Here, the motor 75 vibrates due to pulse drive. If the valve body 71 is fully closed or slightly open, the vibration of the motor 75 is transmitted to at least the valve body 71, and as a result, the valve body 71 comes into contact with the seat 73 and an abnormal noise is generated. be. In particular, if it is determined in step S003 that the received signal is not in the START position, the internal combustion engine 3 has not yet started, so that the passenger of the transportation equipment may hear an abnormal noise.

Therefore, in the present disclosure, the opening degree θ ₀ is obtained by experiments and simulations at the design / development stage of the valve device 7, and even if the motor 75 vibrates due to pulse drive, the valve body 71 does not come into contact with the seat 73. Designed to have an opening.

_{If YES is determined in step S003, the ECU 77 determines the duty ratio D 1} based on, for example, the operating state of the internal combustion engine 3 and the current opening degree θ. The ECU 77 further generates a control signal indicating the determined duty ratio D ₁ and outputs the control signal to the switching element 79 (step S007).

Since the internal combustion engine 3 is started in the state of step S007, the above-mentioned abnormal noise does not matter.

Further, how to set the duty ratio D ₁ can be applied to well-known techniques and publicly-known techniques, and is not a main part of the present disclosure. Therefore, the description thereof will be omitted.

When step S005 or S007 ends, the process returns to step S001.

<2-4. Actions and effects of valve devices>
As described above, according to the valve device 7, the motor 75 not only rotates but also vibrates in response to the supply of the pulse signal. _{However, the opening degree θ 0} is controlled so that the valve body 71 does not come into contact with the seat 73 from the time when the electric system of the transportation equipment is turned on until the start of the internal combustion engine 3. As a result, it is possible to prevent the valve body 71 from coming into contact with the seat 73 and generating an abnormal noise due to the vibration of the motor 75. This makes it possible to prevent this abnormal noise from being heard by the passengers of the transportation equipment.

<3. Modification example>
In the above description, in step S005, the duty ratio D ₀ is set so as to satisfy _{D 0> 0.} However, the present disclosure is not limited to this, and the duty ratio D ₀ may be set to zero in step S005. In other words, the supply of the pulse signal to the motor 75 may be stopped.

In this case, since the motor 75 is stopped, vibration due to pulse drive is not generated. Furthermore, the motor 75 keeps the shaft locked (ie, holding the shaft stopped) when stopped. As a result, not only the vibration from the motor 75 is not transmitted to the valve body 71, but also the valve body 71 is locked by the shaft of the motor 75 even if the vibration from another vibration source is transmitted, so that the seat 73 It is controlled so as not to come into contact with. This makes it possible to prevent this abnormal noise from being heard by the passengers of the transportation equipment.

Further, in the above description, it has been described that the exhaust return passage 5 provided with the valve device 7 is one. However, the present invention is not limited to this, and the number of exhaust / return passages 5 provided with the valve device 7 may be two. In this case, one exhaust return path 5 is provided for one cylinder or group of cylinders among all cylinders, and the other exhaust return path 5 is provided for the remaining cylinders or group of cylinders among all cylinders. Furthermore, the number of exhaust / return passages 5 provided with the valve device 7 may be three or more.

The valve device of the present disclosure can prevent the generation of abnormal noise, and is suitable for transportation equipment such as vehicles.

1 EGR system 3 Internal combustion engine 5 Exhaust gas recirculation path 7 Valve device 71 Valve body 73 Seat 75 Motor 77 Control unit (ECU)
79 switching element

Claims (3)

A valve device used in an EGR that mixes a part of the exhaust gas generated in an internal combustion engine with the intake air to the internal combustion engine via an exhaust gas recirculation path.
A valve body that can open and close the exhaust / return path, and a valve body that sits on a seat provided in the exhaust / return path when fully closed.
A motor that generates a driving force for the valve body when a pulse signal is supplied from the outside is provided.
If the input signal input when the ignition switch is other than OFF does not indicate the START position and is determined to be before the start of the internal combustion engine, (1) the motor uses a pulse signal having a predetermined duty ratio. , A driving force is generated so as to open the valve body at an opening degree at which the valve body does not abut on the seat, or (2) the supply of the pulse signal to the motor is stopped.
Valve device. After the electrical system of the transportation equipment on which the internal combustion engine is mounted is turned on, before the internal combustion engine is started, (2) the supply of the pulse signal to the motor is stopped.
The valve device according to claim 1. A control unit that outputs a control signal indicating the duty ratio,
A switching unit that switches a constant voltage supplied from the outside according to a control signal output from the control unit to generate a pulse signal and supplies the pulse signal to the motor.
Further comprising a,
The control unit determines the duty ratio of the pulse signal based on the current opening degree of the valve body when the input signal indicates the START position, and when the input signal does not indicate the START position, the control unit determines the duty ratio of the pulse signal. The valve device according to claim 1 , wherein the duty ratio is determined.

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