JP2015200226A - valve control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a temperature (electric current heat generation) of each motor portion is over an overheat limit temperature (heat-resisting temperature of each motor portion) by motor driving current flowing in an internal conductor (motor winding portion) of a motor, as a conventional EGR control valve is continued only in a section where a valve element returning speed by spring force of a return spring is decreased.SOLUTION: A flow rate control valve sets a DUTY value of a PWM signal applied to first and third motor driving circuits to a DUTY value capable of decreasing first and third valve element returning speeds to a full-close side by set torque of first and third springs in a full close control. Concretely, by being fixed to the full close holding DUTY values capable of holding the first and third valves at the full close position, motor driving current flowing in an armature coil of a motor M can be reduced in comparison with a conventional technology. Thus a temperature of each motor portion is prevented from being over an overheat limit temperature.

Description

  The present invention relates to a valve control device, and in particular, an EGR valve control device used in an exhaust gas circulation device that recirculates a part of exhaust gas discharged from a cylinder of an internal combustion engine (engine) as EGR gas to an intake pipe. Related to.

[Conventional technology]
2. Description of the Related Art Conventionally, in an internal combustion engine (engine) such as a diesel engine, an exhaust circulation device (EGR system) that reduces nitrogen oxides (NOx) contained in exhaust gas (hereinafter referred to as exhaust) exhausted from a cylinder of the engine has been provided. It is installed.
The EGR system recirculates (refluxs) part of the exhaust discharged from the engine cylinders as EGR gas to the intake passage in the intake pipe and mixes it with intake air (fresh air) that has passed through the air cleaner to lower the combustion temperature. This suppresses the generation of NOx.

Here, if the EGR gas is recirculated to the intake passage, the ignitability of the air-fuel mixture in the combustion chamber formed in the engine cylinder is reduced, leading to a decrease in engine output. Therefore, EGR introduced into the engine cylinder It is necessary to adjust the gas flow rate according to the operating condition of the engine.
Therefore, in the EGR system, an EGR gas flow rate control valve (hereinafter referred to as EGR control valve) is installed in the middle of the EGR gas pipe that connects the branch portion of the exhaust passage in the exhaust pipe and the junction portion of the intake passage in the intake pipe. The flow rate of the EGR gas introduced into the cylinder of the engine is controlled by adjusting the opening degree of the EGR valve that is the valve body of the valve (see, for example, Patent Document 1).

By the way, in order to accurately control the flow rate of the EGR gas in accordance with the operation state of the engine, it is important to accurately detect the position information of the EGR valve of the EGR control valve with the valve position sensor.
Further, the EGR control valve has a motor for generating power for driving the EGR valve, an actuator having a speed reduction mechanism for decelerating the rotation of the motor and transmitting it to an output shaft that supports the EGR valve, and an output gear of the speed reduction mechanism. And a return spring that urges the EGR valve in the fully closed direction, and a housing that houses the speed reduction mechanism and the return spring. The motor is electronically controlled by an electronic control unit (hereinafter referred to as ECU), thereby providing EGR control. The position control of the EGR valve of the valve is performed.

The ECU calculates (sets) the target valve position in accordance with the operating state of the engine, calculates (acquires) the actual valve position from the output signal of the valve position sensor, and eliminates the deviation between the target valve position and the actual valve position. As described above, the duty value of a PWM (pulse width modulation) signal given to the motor drive circuit is feedback-controlled using known PID control.
When the duty value of the PWM signal is given to the motor drive circuit, electric power (motor drive current or motor applied voltage) corresponding to the duty value is supplied to the motor internal conductor (armature coil), and the motor internal conductor A motor driving current in the valve opening direction (the opening side of the EGR valve) or the valve closing direction (the closing side of the EGR valve) flows through the (armature coil). Thereby, the EGR valve is driven to the opening side or the closing side.

Here, when the valve opening degree control of the EGR control valve is performed, when the engine operating range is a predetermined operating range (for example, the engine load is low and the engine speed is low), the engine In order to stabilize the combustion state, the introduction of EGR gas to fresh air is stopped (EGR cut).
In addition, when the driver wants to maximize the engine output by depressing the accelerator pedal, EGR gas against fresh air is avoided in order to avoid a decrease in engine output caused by the introduction of EGR gas into the combustion chamber. Is stopped (EGR cut).
When the engine is stopped, the power supply to the inner conductor (motor winding portion) of the motor is stopped, and the EGR valve of the EGR control valve is operated to the fully closed position only by the urging force of the return spring.

[Conventional technical problems]
However, in the conventional valve opening degree control of the EGR control valve, when the EGR valve of the EGR control valve is operated to the fully closed position at the time of the EGR cut, as shown in FIG. The spring force of the return spring is added to the drive torque of the motor (closed side motor torque) to assist the closing side.
If the closed-side motor torque is transmitted to the EGR valve as it is, the protruding portion of the gear of the reduction mechanism (fully closed stopper portion) may collide with the mechanical stopper through the fully closed position of the EGR valve, and the gear of the reduction mechanism may be damaged. .

  Therefore, a valve position information sensor capable of detecting the EGR valve position (the opening degree of the EGR valve) with respect to the mechanical stopper is attached to open the EGR valve in front of the mechanical stopper in order to decelerate acceleration due to the spring force of the return spring. Power (motor drive current or motor applied voltage) corresponding to the set value (DUTY (%)) of the drive duty that generates the motor drive torque (open motor torque) to the motor side is supplied to the motor winding section As a result, a motor drive current in the valve opening direction (opening side of the EGR valve) flows. As a result, a brake is applied to the valve body return speed toward the closing side of the EGR valve.

Specifically, when the EGR valve fully closes the EGR valve from a predetermined opening degree, the closed-side motor torque is applied to the motor drive circuit until a section (period) in which power is supplied with DUTY = -100% has elapsed. The maximum value of drive DUTY (DUTY = −100%) that generates
Then, power (motor drive current or motor applied voltage) corresponding to the maximum value of drive DUTY (DUTY = -100%) is supplied to the motor winding part of the motor, so the motor winding part of the motor is closed in the valve closing direction. A motor drive current (closed side of the EGR valve) flows. As a result, the EGR valve is driven to close toward the fully closed position (to the closing side).

Then, before the mechanical stopper and before the fully closed position of the EGR valve, a set value (DUTY = + α%) of drive DUTY for generating the open side motor torque is given to the motor drive circuit. This is executed continuously after a section (period) in which power is applied at DUTY = -100%, for a section (period) in which the valve body return speed due to the spring force of the return spring is decelerated.
Then, electric power (motor drive current or motor applied voltage) corresponding to the set value (DUTY = + α%) of the drive DUTY is supplied to the motor winding portion of the motor, so the motor winding portion of the motor is opened in the valve opening direction ( A motor drive current on the opening side of the EGR valve flows. Thereby, the valve body return speed by the spring force to the EGR valve closing side is reduced.
As a result, there is a possibility that the temperature (current heat generation) of each part of the motor exceeds the overheat limit temperature (heat-resistant temperature of each part of the motor), and there is a concern about motor failure or deterioration of durability due to overheating of each part of the motor.

JP 2013-245625 A

  An object of the present invention is to provide a valve control device that can prevent a motor failure and a decrease in durability of the motor due to the temperature of each part of the motor exceeding the overheat limit temperature.

According to the first aspect of the present invention (valve control device), when the valve is operated to the fully closed position or the fully open position, the control signal for the motor is transmitted to the fully closed side or the fully opened side by the set torque of the spring. By setting to a duty value that can be decelerated, the duty value of the control signal for the motor can be reduced.
As a result, the electric power (motor drive current value or motor applied voltage value) supplied to the internal conductor of the motor (for example, the motor winding part) is limited to a setting value or less corresponding to the duty value of the control signal for the motor. Generation | occurrence | production of the malfunction that the temperature of each part exceeds overheat limit temperature (heat-resistant temperature of each part of a motor) can be suppressed. Accordingly, it is possible to prevent a motor failure and a decrease in durability of the motor due to the temperature of each part of the motor exceeding the overheat limit temperature, so that each part of the motor can be protected. Therefore, in the valve control device, it is possible to realize valve control having robustness (reliability and durability with respect to measures for preventing overheating of each part of the motor).

1 is a configuration diagram showing a schematic configuration of a control device (engine control system) for an internal combustion engine (Example 1). FIG. It is sectional drawing which showed the EGR control valve of the normally fully closed structure (Example 1). (Example 1) which is the top view which showed the EGR control valve of the normally fully closed structure of the state which removed the sensor cover. 3 is a flowchart showing a first and third valve (EGR valve) fully closed control method by an ECU (Example 1). 3 is a flowchart showing a second and fourth valve (throttle valve) fully open control method by the ECU (Example 1). 6 is a graph showing the relationship between the drive torque of the output gear and the valve angle (Example 1). 6 is a timing chart showing changes in the opening degree of the EGR valve and changes in the DUTY value during the fully closed control of the EGR control valve (Example 1). It is the timing chart which showed the change of the opening degree of the EGR valve at the time of fully closed control of an EGR control valve, and the change of DUTY value (conventional technique).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Configuration of Example 1]
1 to 7 show an engine control system (Embodiment 1) having an EGR valve control device to which the present invention is applied.

  An internal combustion engine control device (hereinafter referred to as an engine control system) of this embodiment recycles EGR gas, which is part of exhaust gas (hereinafter referred to as exhaust), from an exhaust pipe of an internal combustion engine (engine) E such as a diesel engine to an intake pipe. An exhaust gas recirculation device (hereinafter referred to as an EGR system) that circulates (returns), a turbocharger that supercharges (compresses) intake air (intake air) using the pressure of exhaust gas discharged from a cylinder of the engine E, and an EGR system An engine control unit (to be described later) that is controlled in association with each system such as a throttle and a fuel supply system is used, and is used as an exhaust purification device that purifies exhaust discharged from the engine E.

The engine E is a vehicle traveling engine mounted on a vehicle such as an automobile, and is a multi-cylinder diesel engine that burns a mixture of fuel and air injected from the injector I.
An intake duct (intake pipe) that forms an intake passage through which intake air (new air) or EGR gas that has passed through the air cleaner 8 flows is connected to an intake port of each cylinder of the engine E via an intake manifold. Further, an exhaust duct (exhaust pipe) that forms an exhaust passage through which exhaust exhausted from a combustion chamber formed in each cylinder of the engine E flows is connected to an exhaust port of each cylinder of the engine E via an exhaust manifold. Has been.

  The turbocharger includes a compressor C provided in the middle of the intake pipe of the engine E and a turbine T provided in the middle of the exhaust pipe of the engine E, and the compressor C compresses the intake air flowing through the intake passage in the intake pipe. A turbocharger that sends compressed air (intake) that has been compressed into each cylinder of the engine E. In the turbocharger, when the turbine T is rotationally driven by the pressure of exhaust gas, the compressor C drivingly connected to the turbine T also rotates, and the compressor C compresses the intake air.

The fuel supply system is configured by a common rail fuel injection system (accumulated pressure fuel injection device) known as a fuel injection system for a diesel engine.
The common rail fuel injection system includes an ultra-high pressure fuel pump (hereinafter referred to as a supply pump) P having a built-in feed pump that pumps fuel from a fuel tank through a fuel filter, and fuel into which high-pressure fuel discharged from the supply pump P is introduced. A distribution pipe (hereinafter referred to as a common rail) R and a plurality of injectors (fuel injection valves for an internal combustion engine) I into which high-pressure fuel distributed from the common rail R is introduced are stored in the common rail R (accumulation chamber). The high-pressure fuel is injected and supplied into the combustion chamber formed in each cylinder of the engine E through each injector I.

On the other hand, the EGR system includes a “high pressure loop (HPL) -EGR system” and a “low pressure loop (LPL) -EGR system”.
In the HPL-EGR system, as shown in FIG. 1, the EGR gas take-out port from the exhaust passage in the exhaust pipe is provided upstream of the turbine T of the turbocharger in the exhaust flow direction.
The HPL-EGR system includes an EGR gas pipe that recirculates EGR gas from an exhaust passage in the exhaust manifold or the exhaust pipe to an intake passage in the intake manifold or the intake pipe. The EGR gas pipe is provided with a normally closed type flow rate control valve 1 for controlling (adjusting) the flow rate of the EGR gas. Further, a normally open type flow rate control valve 2 for controlling (adjusting) the flow rate of fresh air is provided upstream of the merge portion of the EGR gas pipe with respect to the intake pipe in the intake flow direction.

In the LPL-EGR system, as shown in FIG. 1, the EGR gas take-out port from the exhaust passage in the exhaust pipe is provided downstream in the exhaust flow direction from the turbine T of the turbocharger.
The LPL-EGR system includes an EGR gas pipe that recirculates EGR gas from an exhaust passage in the exhaust pipe to an intake passage in the intake pipe. The EGR gas pipe is provided with a normally closed type flow rate control valve 3 for controlling (adjusting) the flow rate of the EGR gas. Further, a normally open type flow control valve 4 for controlling (adjusting) the flow rate of exhaust gas is provided downstream of the branch portion of the EGR gas pipe with respect to the exhaust pipe in the exhaust flow direction.

In the EGR gas pipe, the first and third valve shafts (hereinafter referred to as output shafts 15) of the flow control valves 1 and 3 are rotationally driven, and the first and third valve bodies (EGR valves) of the flow control valves 1 and 3 are driven. : The electric actuator 5 for opening and closing the first and third valves 11 and 13) is mounted.
In addition, the second and fourth valve shafts (hereinafter referred to as output shafts 16) of the flow control valves 2 and 4 are rotationally driven in the intake pipe and the exhaust pipe, respectively. An electric actuator 6 for opening and closing a valve body (throttle valve: hereinafter, second and fourth valves 12 and 14) is mounted.
And the electric actuators 5 and 6 send the drive torque of the 1st-4th electric motor (henceforth motor) M which opens / closes each 1st-4th valve 11-14 of the flow control valves 1-4 to the output shaft 15, Tell 16

  The flow rate control valves 1 and 3 are first and third valves 11 and 13 for opening and closing first and third flow paths (described later) communicating with combustion chambers formed in the respective cylinders of the engine E, and the first. And an output shaft 15 connected to the third valves 11 and 13 so as to be integrally rotatable, and a motor M that generates power (driving torque) for driving the first and third valves 11 and 13 to open and close. The electric actuator 5 that transmits torque to the output shaft 15, the mechanical stopper 17 that defines the fully closed positions of the first and third valves 11 and 13, and the direction in which the first and third valves 11 and 13 are pressed against the mechanical stopper 17 (all Position information (rotation angle, actual valve position) of the first and third return springs (hereinafter referred to as first and third springs) SP, which are biased in the closing direction and the valve closing direction, and the first and third valves 11 and 13. (Actual valve opening) And a first, third valve opening sensor (hereinafter valve opening sensor) 18 for outputting a signal.

The electric actuator 5 includes a motor M whose drive current value flowing through the inner conductor is duty controlled, and first and third reduction mechanisms (described later) that reduce the rotation of the output shaft (motor shaft) of the motor M by two stages. )have.
The mechanical stopper 17 includes a first restricting portion that mechanically restricts movement of the output portion (hereinafter, first and third output gears) 19 of the electric actuator 5 and the first and third valves 11 and 13 to the closing side. A fully-closed stopper (fixed stopper).
Further, the first and third springs SP are in the direction in which the first and third valves 11 and 13 are pressed against the mechanical stopper 17 against the first and third output gears 19 of the electric actuator 5 (fully closed direction, valve closed state). It is a coil spring that generates a biasing force (spring force) biasing in the direction).

  The flow rate control valves 2 and 4 are second and fourth valves 12 and 14 for opening and closing second and fourth flow paths (described later) communicating with combustion chambers formed in the cylinders of the engine E, and the second. And an output shaft 16 connected to the fourth valves 12 and 14 so as to be integrally rotatable, and a motor M that generates power (driving torque) for driving the second and fourth valves 12 and 14 to open and close. For the electric actuator 6 that transmits torque to the output shaft 16, a mechanical stopper (not shown) that defines the fully open positions of the second and fourth valves 12 and 14, and the second and fourth output gears of the electric actuator 6, Second and fourth return springs (hereinafter referred to as second and fourth return springs) that generate urging forces (spring forces) for urging the second and fourth valves 12 and 14 against the mechanical stoppers (full opening direction and valve opening direction). Spring: not shown ) And second and fourth valve opening sensors (hereinafter referred to as valve opening sensors) that output signals corresponding to position information (rotation angle, actual valve position, actual valve opening) of the second and fourth valves 12 and 14. : Not shown).

The electric actuator 5 includes a motor M in which a drive current value flowing through the inner conductor is duty controlled, and second and fourth reduction mechanisms (described later) that reduce the rotation of the output shaft (motor shaft) of the motor M by two stages. )have.
The mechanical stopper mechanically restricts the movement of the output portion of the electric actuator 6 (hereinafter, second and fourth output gears: not shown) and the second and fourth valves 12 and 14 to the opening side. A fully open stopper (fixed stopper) having a portion.
The second and fourth springs are attached to the second and fourth output gears of the electric actuator 6 in the direction in which the second and fourth valves 12 and 14 are pressed against the mechanical stopper (full open direction and valve open direction). This is a coil spring that generates a biasing force (spring force).

The intake pipe connected to the intake manifold (surge tank) of the intake manifold of the engine E includes an air cleaner 8 that filters out foreign substances contained in fresh air (outside air), a turbocharger compressor C, and intake air that has passed through the compressor C. A water-cooled intercooler 9 that cools the water by exchanging heat with cooling water, and a flow rate control valve 2 that regulates the flow rate of fresh air that has passed through the intercooler 9 are installed.
The exhaust pipe connected to the exhaust manifold of the exhaust manifold of the engine E includes a turbine T of the turbocharger and a diesel particulate filter (exhaust gas purification device :) that collects exhaust particulates (particulate matter: PM) contained in the exhaust. DPF) 10 and a flow rate control valve 4 for adjusting the flow rate of the exhaust gas that has passed through the DPF 10 are installed.

The HPL-EGR system and the LPL-EGR system are EGR valves that control the opening and closing of the first to fourth valves 11 to 14 that are the first to fourth valve bodies of the flow control valves 1 to 4 based on the operating state of the engine. It is used as a control device (EGR control device for an internal combustion engine).
This EGR valve control device is incorporated in a motor M incorporated in the electric actuator 5 that rotationally drives the output shaft 15 of the flow control valves 1, 3 and an electric actuator 6 that rotationally drives the output shaft 16 of the flow control valves 2, 4. An engine control unit (electronic control unit: ECU) 20 that controls the motor M to be operated in conjunction with another system is provided.

Next, the details of the flow control valves 1 to 4 of this embodiment will be briefly described with reference to FIGS.
The flow control valves 1, 3 fully close the first and third flow paths 21, 23 through which EGR gas flows when energization of the motor M, which is a power source of the electric actuator 5, is stopped. A normally closed (N / C) type EGR gas flow rate control valve (hereinafter referred to as “NGR”) that increases the cross-sectional area of the first and third flow paths 21 and 23 stepwise or continuously as the voltage increases or the applied voltage increases. EGR control valve).
The EGR gas that has passed through the water-cooled EGR cooler EC1 that cools the EGR gas by exchanging heat with the cooling water is introduced into the flow control valve 1. In addition, the EGR gas that has passed through the water-cooled EGR cooler EC2 that cools the EGR gas by exchanging heat with the cooling water is introduced into the flow control valve 3. The EGR gas introduced from the exhaust pipe flows through the first and third flow paths 21 and 23.

When the energization of the motor M is stopped, the flow control valve 2 fully opens the second flow path 22 through which fresh air flows, and the flow of the second flow path 22 increases as the drive current to the motor M increases or the applied voltage increases. It is a normally open (N / O) type flow control valve that reduces the road cross-sectional area stepwise or continuously.
Note that fresh air that has passed through the air cleaner 8 flows through the second flow path 22.
In addition, in the intake pipe of the present embodiment, intake air in which EGR gas introduced from the first flow path 21 and fresh air introduced from the second flow path 22 are mixed is introduced into the combustion chamber of each cylinder of the engine E. A third flow path 23 is provided.

The flow rate control valve 4 fully opens the fourth flow path 24 through which the exhaust flows when energization of the motor M is stopped, and the flow path of the fourth flow path 24 increases as the drive current to the motor M increases or the applied voltage increases. It is a normally open (N / O) type flow control valve that reduces the cross-sectional area stepwise or continuously.
The fourth flow path 24 is exhausted from the combustion chamber of each cylinder of the engine E, and exhaust gas that has passed through the turbine T and the DPF 10 of the turbocharger flows.

The fourth flow path 24 is provided in the exhaust pipe of this embodiment. The exhaust gas flowing through the fourth flow path 24 corresponds to the flow rate of the EGR gas flowing into the third flow path 23 and the exhaust gas flowing into the fourth flow path 24 as it is in accordance with the valve opening degree with the flow control valves 3 and 4. The flow rate is divided.
As described above, the flow control valves 1 and 3 and the flow control valves 2 and 4 are two types of fluid control valves having different usage states (specifications) of common parts, that is, a normally fully closed flow control valve and a normally fully open. And a flow control valve having a structure.

  Next, details of the flow control valves 1 and 3 of this embodiment will be briefly described with reference to FIGS. Here, since the configuration of the flow control valve 1 and the configuration of the flow control valve 3 are the same, only the configuration of one flow control valve 1 will be described, and the detailed description of the other flow control valve 3 will be omitted. . Further, detailed description of the flow control valves 2 and 4 is also omitted.

  The flow rate control valve 1 includes a first valve 11 that regulates the flow rate of the EGR gas flowing through the first flow path 21, an output shaft 15 that is connected to the first valve 11 so as to rotate integrally therewith, and the output shaft 15 that rotates. An electric actuator 5 that drives to open and close the first valve 11, and a housing 25 that houses (incorporates) the first valve 11, the output shaft 15, and the electric actuator 5 are provided.

Inside the housing 25, an EGR gas passage (first passage 21) through which EGR gas flows from an exhaust passage in the exhaust pipe toward an intake passage in the intake pipe is formed. The housing 25 is provided with a concave portion for housing the electric actuator 5 between the sensor cover 26 made of synthetic resin on which the valve opening sensor 18 is mounted.
The sensor cover 26 includes a pair of brush terminals 28 protruding from the front bracket 27 of the motor M and an internal connection connector for electrical connection between the pair of motor terminals, and a plurality of the pair of motor terminals and the valve opening sensor 18. An external connection connector for providing electrical connection between the sensor terminal and an external circuit (ECU 20 or battery) is provided.

The flow control valve 1 changes the opening area of the EGR gas flow path (first flow path 21) formed inside the housing 25 continuously or stepwise, via the first flow path 21, It is used as an EGR gas flow rate control valve (EGR control valve) that variably controls the flow rate (EGR gas amount) of EGR gas recirculated (recirculated) from the exhaust passage to the intake passage.
The flow control valve 1 includes a shaft support mechanism (support mechanism for the output shaft 15) that rotatably supports the output shaft 15 with respect to the housing 25. The shaft support mechanism includes a rolling bearing (hereinafter referred to as a ball bearing) 31, an oil seal 32, a sliding bearing (guide bush) 33, a gas seal (or dust seal) 34, and the like.

The flow control valve 1 is fully closed when the engine is stopped or when EGR gas is not introduced (EGR cut), and is orthogonal to the axial direction of the seal ring 36 fitted in the seal ring groove 35 of the first valve 11. The annular gap formed between the valve seat surface of the nozzle 37 and the outer peripheral end surface of the first valve 11 is sealed (airtight seal) by using the radial (expanding direction) tension. Yes.
The first valve 11 is fixed by welding to one end portion (first projecting portion) of the output shaft 15 in the rotation axis direction. Further, an annular seal ring groove 35 is continuously formed in the circumferential direction on the outer peripheral end face of the first valve 11.

The first valve 11 is a valve body of an exhaust throttle valve that restricts the flow path cross-sectional area of the first flow path 21 by being rotated within an operable range from the fully closed position to the fully open position. The EGR rate, which is the ratio of the EGR gas flow rate to the total flow rate of intake air (only fresh air or fresh air + EGR gas) supplied into the combustion chamber of each cylinder, is adjusted.
A C-shaped seal ring 36 is fitted into the seal ring groove 35 of the first valve 11. This seal ring 36 has a circumferential shape in consideration of the assembling property of the first valve 11 with respect to the seal ring groove 35 or in preparation for expansion and contraction of the seal ring 36 due to a difference in thermal expansion with the cylindrical nozzle 37. A predetermined notch gap (abutment gap) is provided between both end faces in the direction (abutment).
Further, an outer peripheral surface (sliding portion) that can be in close contact with the inner diameter surface (valve seat surface) of the nozzle 37 is provided on the outer end surface in the radial direction of the seal ring 36.

The output shaft 15 is rotatably accommodated in the bearing sleeve 38 of the housing 25.
A first protruding shaft portion that protrudes from the opening end surface of the bearing hole of the bearing sleeve 38 toward the inside of the first flow path 21 is provided at one end portion of the output shaft 15 in the rotation axis direction. In addition, the 1st valve | bulb 11 is fixed by welding to the 1st protrusion shaft part.
Further, a second projecting shaft portion that projects from the opening end surface of the bearing sleeve 38 of the housing 25 toward the inside of the gear housing space is provided at the other end portion of the output shaft 15 in the rotation axis direction. A small-diameter shaft portion on which a metal insert plate (hereinafter referred to as a metal plate) 39 for coupling to the first output gear 19 is fixed by caulking is provided on the distal end side of the second projecting shaft portion in the rotation axis direction. Yes.

Next, details of the electric actuator 5 of this embodiment will be described with reference to FIGS. The electric actuator 5 includes a motor M and a first reduction mechanism.
The motor M is a brushed DC motor in which an inner rotor is disposed on the inner peripheral side of the outer stator so as to be relatively rotatable, and an inner rotor (armature) having a motor shaft (motor shaft) extending straight in the rotation axis direction; A cylindrical stator surrounding the armature in the circumferential direction (motor circumferential direction), and a pair of power supply brushes (first and second brushes) housed and held in a brush holder fixed to the stator It has.

The stator of the motor M has a motor case (such as a motor yoke) that rotatably accommodates the motor shaft of the armature, and a plurality of field magnets fixed to the inner peripheral surface of the motor yoke.
The pair of first and second brushes constitute the inner conductor of the motor M, and are disposed at intervals of 180 ° in the circumferential direction of the motor and opposed to each other. The first brush is connected to the positive electrode side (VCC side) of the external power source (battery) via one brush terminal 28 and the power supply line. The second brush is connected to the negative side (ground side, GND side) of the external power source (battery) via the other brush terminal 28 and the power supply line.

  The armature of the motor M is installed through a predetermined gap on the radially inner side of the stator. The armature includes a motor shaft rotatably supported by bearing support portions (bearing holders) of the front bracket 27 and the motor yoke via bearings (metal bearings), and a magnetic steel plate in the rotational axis direction of the motor shaft. Armature core (armature core) formed by laminating a plurality of armature cores, an armature winding (armature coil) wound around the armature core, and a pair of first and second brushes. Commutator.

The armature core is formed of a laminated iron core, and includes a cylindrical (or rectangular tube) fitting portion press-fitted to the outer periphery of the motor shaft, and a plurality of teeth protruding from the outer peripheral surface of the fitting portion. Have.
A plurality of slots are formed between the teeth adjacent to each other in the circumferential direction of the armature core to store the phase coils of the armature winding.
The armature coil constitutes the internal conductor of the motor M together with the brush terminal 28, the motor terminal, the first and second brushes, and the commutator, and is wound around each tooth winding portion of a plurality of teeth by a concentrated winding method. The multiphase coils are housed in the slots. Each phase coil is wound around the outside of each tooth winding part via an insulator.

The metal bearing is a cylindrical sintered oil-impregnated bearing (metal bush) formed of a sintered material, having a large number of pores therein, and impregnating the internal pores with lubricating oil. A large number of internal cylinder openings (surface pores) are formed in the hole wall surface (inner diameter surface).
This metal bearing has an opening on the sliding surface (inner diameter surface) with the motor shaft due to the lubricating oil penetrating into the internal pores due to the negative pressure generated by the rotational movement of the motor shaft inserted into the sliding hole. By oozing out, an oil film is formed at the sliding portion between the inner diameter surface of the metal bearing and the outer diameter surface of the motor shaft, and the motor shaft is rotatably supported by this oil film.

The first spring SP is spirally wound between a spring hook (engagement recess: hereinafter referred to as a movable hook) 41 of the first output gear 19 and a spring hook (step surface: hereinafter referred to as a fixed hook) 42 of the housing 25. The first and second bent portions obtained by bending the both end portions of the coil portion radially outward, and straight from the first and second bent portions outward in the radial direction. Have two terminal wires (spring side hook: hereinafter referred to as a terminal).
The first spring SP is installed so as to spirally surround the output shaft 15, the cylindrical portion (bearing holder) 43 of the housing 25, and the cylindrical boss 44 of the first output gear 19.

Here, the speed reduction mechanism includes a first output gear 19 connected to the output shaft 15 of the first valve 11 so as to be integrally rotatable, a motor shaft of the motor M, an intermediate shaft 45 arranged in parallel with the output shaft 15, and a motor shaft. And a motor gear (hereinafter referred to as a pinion gear) 46 that is connected to the pinion gear 46 and an intermediate reduction gear (hereinafter referred to as an intermediate gear) 47 that rotates in mesh with the pinion gear 46.
The pinion gear 46 has a cylindrical portion fixed to the outer periphery of the tip of the motor shaft of the motor M by press-fitting or the like. On the outer periphery of the cylindrical portion, pinion gear teeth 51 that mesh with the intermediate gear 47 are formed.
The intermediate gear 47 is fitted to the outer periphery of the intermediate shaft 45 so as to be relatively rotatable, and has a cylindrical portion that rotates around the central axis of the intermediate shaft 45. A large-diameter gear (intermediate gear tooth) 52 that meshes with the pinion gear teeth 51 is formed at one end of the cylindrical portion in the axial direction. A small-diameter gear (intermediate gear teeth) 53 that meshes with the first output gear 19 is formed at the other end in the axial direction of the cylindrical portion.

The first output gear 19 constitutes an output portion of the speed reduction mechanism together with the output shaft 15, meshes with the intermediate gear 47 and rotates. A cylindrical boss 44 having a circular through hole is integrally formed in the inner peripheral portion of the first output gear 19.
The first output gear 19 has a partially cylindrical (fan-shaped) tooth forming portion integrally formed on the outer side in the radial direction than the cylindrical boss 44. The tooth forming portion is formed in a fan shape by a predetermined angle. Further, output gear teeth 54 that mesh with the intermediate gear teeth 53 are formed on the outer peripheral portion of the tooth forming portion.
A metal plate 39 as an insert member is insert-molded on the tip end side of the cylindrical boss 44 of the first output gear 19. A small-diameter shaft portion of the second projecting shaft portion of the output shaft 15 is fitted and fixed to the center portion of the metal plate 39 using a coupling means such as caulking.

Further, a fully closed stopper portion 55 having a flat surface (planar) shape is integrally formed on one end side surface (closed side surface) in the rotation direction of the tooth forming portion. When the first valve 11 is fully closed, the fully closed stopper portion 55 comes into contact with and is engaged with the discharge portion (mechanical stopper 17) of the housing 25. As a result, when the fully closed stopper portion 55 of the first output gear 19 comes into contact with the mechanical stopper 17, the first valve 11, the output shaft 15 and the first output gear 19 are further rotated in the valve closing direction. Be regulated.
The mechanical stopper 17 has a flat restricting surface and is provided at a position spaced from the fully closed position of the first valve 11 by a predetermined distance in the rotation direction of the first valve 11, the output shaft 15 and the first output gear 19. ing.

Here, the motor M which is a power source of the electric actuators 5 and 6 is electrically connected to an external power source (battery) mounted on a vehicle such as an automobile via first to fourth motor drive circuits electronically controlled by the ECU 20. Connected.
The ECU 20 includes a microcomputer having a known structure including functions of a CPU, a memory (ROM and RAM, and an EEPROM), an input circuit (input unit), an output circuit (output unit), a power supply circuit, a timer circuit, and the like. Is provided.
The first to fourth motor drive circuits are respectively configured by first to fourth H bridge circuits in which, for example, four semiconductor switch elements are bridge-connected.

The first to fourth motor drive circuits supply power (motor drive current or motor) to the internal conductor (armature coil) of the motor M with respect to a control signal (for example, duty ratio of PWM signal) given from the microcomputer of the ECU 20. The applied voltage is variably controlled.
Here, the drive duty value (DUTY (%)) given to the first to fourth motor drive circuits is that the actual valve position (actual opening or actual EGR rate) is the target valve position (target opening or target EGR rate). In the generation period (PWM period) of the PWM signal (pulse width modulation signal), the ON period in which the inner conductor (for example, armature coil) of the motor M is energized and the energization to the inner conductor of the motor M are stopped. It is the ratio (ON / OFF ratio) with the OFF period.

  In the EGR valve control device of the present embodiment, the first and third motors that control the energization of the motor M that generates power for opening and closing the first and third valves 11 and 13 of the flow control valves 1 and 3. The valve control start timing of the drive circuit and the second and fourth motor drive circuits that perform energization control of the motor M that generates power for opening and closing the second and fourth valves 12 and 14 of the flow control valves 2 and 4 is determined. Configured differently. For example, the valve control is started after the second and fourth motor drive circuits are delayed from the first and third motor drive circuits. Specifically, the valve control in the second and fourth motor drive circuits is started when the operating condition (operating condition of the engine E) is such that the EGR gas is difficult to return to the intake passage during the EGR valve opening operation. That is, the second and fourth valves 12 and 14 are operated so as to close the cross-sectional areas of the second and fourth flow paths 22 and 24.

The CPU performs various numerical calculation processes, information processing (for example, valve position information processing) and control (for example, valve control, motor energization control) and the like according to programs.
The ROM stores in advance programs necessary for various numerical calculation processes, information processing, and control of the CPU.
In the RAM, intermediate information obtained by the arithmetic processing of the CPU is temporarily recorded, and the stored information disappears when the ignition switch (engine switch) is turned off.
The EEPROM stores information necessary for various numerical computation processing, information processing, control, and the like by the CPU. More specifically, a data table representing the correspondence between the valve positions (actual opening) of the flow control valves 1 to 4 and the sensor output signal (sensor output voltage output from the valve opening sensor 18) in a predetermined format. Etc. are stored in advance in the EEPROM.

A sensor output signal (analog voltage) from the valve opening sensor 18 and sensor output signals (electrical signals) from various sensors are A / D converted by an A / D conversion circuit, and then input to the microcomputer. It is comprised so that it may be input.
Here, not only the valve opening sensor 18 but also an air flow meter, a crank angle sensor, an accelerator opening sensor, a throttle opening sensor, an intake air temperature sensor, a water temperature sensor, and an exhaust gas sensor (air-fuel ratio sensor) are included in the input portion of the microcomputer. , Oxygen concentration sensor) and the like are connected.

The rotation angle detection device is a cylindrical magnetic circuit unit, and a valve opening sensor 18 that detects the valve position information (opening and valve angle) of the flow control valves 1 to 4 by measuring the rotation angle of the magnetic circuit unit. A change in the relative rotation angle between the magnetic circuit unit and the valve opening sensor 18 is detected by a magnetic change applied to the valve opening sensor 18 from the magnetic circuit unit.
The valve opening sensor 18 is sandwiched and held between opposing portions of a pair of stator cores 57 installed on the sensor mounting portion 56 of the sensor cover 26. The valve opening sensor 18 is mainly composed of a Hall IC that outputs a sensor output signal (analog voltage signal: sensor output voltage) corresponding to the magnetic flux density that links the magnetic sensing surface of the semiconductor Hall element to the ECU 20. ing.

The Hall IC is a magnetic sensor in which a Hall element and an integrated circuit are integrated as a single IC chip (semiconductor chip). Instead of the Hall IC, a non-contact type magnetic detection element such as a Hall element alone or a magnetoresistive element may be used.
The magnetic circuit portion is fixed to the inner periphery of the cylindrical boss 44 that is installed on the cylindrical boss 44 of the first output gear 19 so as to be integrally rotatable with an adhesive or the like. When the material of the cylindrical boss 44 of the first output gear 19 is a synthetic resin, the magnetic circuit portion may be insert-molded on the cylindrical boss 44.
The magnetic circuit section includes a pair of partial cylindrical sensor yokes 58 divided into two in the diameter direction of the cylindrical boss 44 and a pair of magnetic poles arranged in the same direction in the divided section (opposing section) of the sensor yoke 58. Sensor magnet (permanent magnet) 59.

The crank angle sensor includes a pickup coil that converts the rotation angle of the crankshaft of the engine into an electric signal. For example, a sensor output signal (hereinafter referred to as NE pulse signal) is sent to the ECU 20 every 15 ° or 30 ° CA (crank angle). Is output.
The ECU 20 is a rotation speed detection means for detecting the engine rotation speed (engine rotation speed: NE) by measuring the interval time of the NE pulse signal output from the crank angle sensor.

The ECU 20 includes valve position detection means for detecting valve position information (actual opening degree, valve angle) of the flow control valves 1 to 4 based on a sensor output signal (sensor output voltage) output from the valve opening degree sensor 18. It is composed.
The accelerator opening sensor is an engine load detecting means for outputting an electric signal (sensor output signal) corresponding to the accelerator pedal depression amount (accelerator opening: ACCP) to the ECU 20. If a throttle opening sensor that detects valve position information (throttle opening, actual opening, valve angle) of the flow control valve 2 is mounted, use the throttle opening sensor as engine load detection means. Also good.

  Here, when the ignition switch (engine switch) is turned on (IG / ON), the ECU 20 firstly calculates (calculates) various engine operating conditions (engine information) or operating conditions (states). A sensor output signal is acquired (input), and the motors M of the electric actuators 5 and 6 are electronically controlled based on the operating state or operating conditions of the engine and the program stored in the ROM.

  The ECU 20 corresponds to the engine operating status (for example, the fresh air amount measured from the sensor output signal (intake flow rate signal) output from the air flow meter, and the engine speed (NE) measured from the NE signal of the crank angle sensor). The control target value (target valve position or target EGR rate) is calculated (determined), and there is no deviation between the actual valve position (actual EGR rate) measured from the sensor output voltage of the valve opening sensor 18 and the target valve position. As described above, the control signal (for example, the duty ratio (value) of the PWM signal: the set value of the drive duty (DUTY = ± α%)) given to the motor drive circuit is feedback-controlled using the known PID control. Has been.

Then, the motor M from the ECU 20 to the side that opens the first and third valves 11 and 13 against the urging force (spring force) of the first and third springs SP with respect to the first and third motor drive circuits. When a drive duty setting value (DUTY = + α%) for generating a drive torque (drive torque exceeding the set torque of the return spring; hereinafter referred to as open side motor torque) is given, the power corresponding to DUTY = + α% (motor drive) Current or motor applied voltage) is supplied to the inner conductor (armature coil) of the motor M, and the motor drive current in the valve opening direction (the opening side of the first and third valves 11 and 13) is applied to the armature coil of the motor M. Flowing. Accordingly, the first and third valves 11 and 13 are driven to open toward the opening side against the spring force of the first and third springs SP.
Note that when the drive duty value is changed from the minimum value (DUTY = 0%) to the maximum value (DUTY = + 100%), the first and third valves 11 and 13 are opened from the fully closed position to the fully open position ( (See FIG. 6). Further, the torque of the first and third output gears 19 has a predetermined open-side hysteresis with respect to the change of the set torque of the return spring with respect to the valve angle (see FIG. 6).

Further, the motor M toward the side of closing the first and third valves 11 and 13 that assists the urging force (spring force) of the first and third springs SP from the ECU 20 to the first and third motor drive circuits. When a drive duty setting value (DUTY = −α%) for generating a drive torque (drive torque below the set torque of the return spring; hereinafter referred to as closed motor torque) is given (DUTY = −α%), power corresponding to DUTY = −α% ( Motor drive current or motor applied voltage) is supplied to the inner conductor (armature coil) of the motor M, and the motor drive in the valve closing direction (close side of the first and third valves 11 and 13) is applied to the armature coil of the motor M. Current flows. As a result, the first and third valves 11 and 13 are driven to close to the closing side while assisting the spring force of the first and third springs SP.
If the drive duty value is changed from the maximum value (DUTY = 0%) to the minimum value (DUTY = -100%), the first and third valves 11 and 13 are closed from the fully open position to the fully closed position. (See FIG. 6). Further, the torque of the first and third output gears 19 has a predetermined closing side hysteresis with respect to the change of the set torque of the return spring with respect to the valve angle (see FIG. 6).

  Further, the ECU 20 moves the motor M from the ECU 20 toward the side where the second and fourth valves 12 and 14 are closed against the urging force (spring force) of the second and fourth springs against the second and fourth motor drive circuits. When a drive duty setting value (DUTY = + α%) for generating drive torque (drive torque exceeding the set torque of the return spring: hereinafter closed motor torque) is given, similarly, the armature coil of the motor M is closed. The motor drive current flows in the direction (closed side of the second and fourth valves 12 and 14). As a result, the second and fourth valves 12 and 14 are driven to open toward the closing side against the spring force of the second and fourth springs.

  Further, the ECU 20 assists the urging forces (spring forces) of the second and fourth springs with respect to the second and fourth motor drive circuits, and opens the second and fourth valves 12 and 14 to the side where the motor M is opened. When a drive duty setting value (DUTY = −α%) for generating drive torque (drive torque lower than the set torque of the return spring; hereinafter referred to as open-side motor torque) is given, similarly, the armature coil of the motor M is opened. Motor drive current flows in the valve direction (the side where the second and fourth valves 12 and 14 are opened). Thus, the second and fourth valves 12 and 14 are driven to close to the closing side while assisting the spring forces of the second and fourth springs.

[Control Method of Example 1]
Next, the valve control method of the EGR valve control apparatus of this embodiment will be briefly described with reference to FIGS.
Here, FIG. 4 is a flowchart showing a first and third valve (EGR valve) fully closed control method by the ECU 20. FIG. 5 is a flowchart showing a second and fourth valve full open control method by the ECU 20. The control routines of FIGS. 4 and 5 are repeatedly executed at predetermined control cycles after the ignition switch is turned on.

First, when the ignition switch is turned on (IG / ON), the ECU 20 is necessary to determine the operating states of the first to fourth valves 11 to 14 of the flow control valves 1 to 4 and the operating state of the engine. Various sensor output signals and DUTY values (DUTY (%)) given to the motor drive circuit are acquired.
Instead of DUTY (%), the motor applied voltage applied to the inner conductor (armature coil) of the motor M and the motor drive current flowing through the inner conductor (armature coil) of the motor M are measured to determine the first. -You may determine the valve opening degree (angle) of each flow control valve 1-4 which is the operation state of the 4th valves 11-14.

  The ECU 20 determines (determines) whether or not the fully closed control for returning the first and third valves 11 and 13 of the flow rate control valves (EGR control valves) 1 and 3 to the fully closed position is being performed (step S11). When this determination result is No, normal EGR control (normal control) during engine operation is performed (step S12). Thereafter, the control routine of FIG. 4 is exited. That is, the process returns to START of the control routine of FIG.

When it is time to enter normal control, the ECU 20 causes the driver to depress the accelerator pedal, and when the engine E enters a predetermined operating range (for example, a low load to medium load and low speed to medium speed rotation region) A control target value (target opening degree, target EGR rate) set corresponding to this operation region (engine load and engine speed) is calculated.
At this time, for example, the ECU 20 opens the first and third valves so that each of the first and third valves 11 and 13 of the flow control valves 1 and 3 opens more than a predetermined valve opening (rotation angle with respect to the fully closed position). A set value (DUTY = + α%) of drive DUTY is given to the motor drive circuit.

When DUTY = + α% is given from the ECU 20 to the first and third motor drive circuits, DUTY = + α% is applied to the inner conductor (motor winding portion: hereinafter referred to as an armature coil) of the motor M of the electric actuator 5. Electric power (motor drive current or motor applied voltage) is supplied, and the motor drive current flows in the valve opening direction (opening side of the first and third valves 11 and 13) through the armature coil of the motor M. As a result, the first and third valves 11 and 13 are opened toward the fully open position.
It should be noted that when the ECU 20 gives the maximum value (DUTY = + 100%) of the drive DUTY to the first and third motor drive circuits, the first and third valves 11 and 13 of the flow control valves 1 and 3 are fully opened. Set to

  On the other hand, the ECU 20 determines (determines) whether or not the flow control valves (intake throttle valve, exhaust throttle valve) 2 and 4 are under full open control for returning the second and fourth valves 12 and 14 to the full open position ( Step S21). When this determination result is No, normal EGR control (normal control) during engine operation is performed (step S22). Thereafter, the control routine of FIG. 5 is exited. That is, the process returns to START of the control routine of FIG.

When it is necessary to enter the normal control, the ECU 20, for example, sets the second and fourth valves 12 and 14 of the flow control valves 2 and 4 below a predetermined valve opening (rotation angle with respect to the fully opened position) if necessary. A set value (DUTY = + α%) of drive DUTY is given to the second and fourth motor drive circuits so as to close the valve.
Then, when DUTY = + α% is given from the ECU 20 to the second and fourth motor drive circuits, DUTY = + α% is applied to the inner conductor (motor winding portion: hereinafter, armature coil) of the motor M of the electric actuator 6. Electric power (motor drive current or motor applied voltage) is supplied, and the motor drive current in the valve closing direction (the closing side of the second and fourth valves 12 and 14) flows through the armature coil of the motor M. As a result, the second and fourth valves 12 and 14 are operated to close toward the fully closed position.
When the ECU 20 gives the maximum value of drive DUTY (DUTY = + 100%) to the second and fourth motor drive circuits, the second and fourth valves 12 and 14 of the flow control valves 2 and 4 are fully closed. Set to position.

By the above, for example, the first and third valves 11 and 13 of the flow control valves 1 and 3 are driven to open, and the flow passage cross-sectional areas of the first and third flow passages 21 and 23 are enlarged. Further, for example, the second and fourth valves 12 and 14 of the flow rate control valves 2 and 4 are driven to close, and the cross-sectional areas of the second and fourth flow paths 22 and 24 are reduced.
Therefore, a part of the exhaust discharged from the combustion chamber of each cylinder of the engine E becomes EGR gas and flows into the EGR gas pipe from the exhaust passage in the exhaust pipe, and is taken in through the first and third flow paths 21 and 23. It is introduced into the intake passage in the pipe. At this time, fresh air (or EGR gas + fresh air) and EGR gas that have passed through the air cleaner 8 are mixed and supplied to the intake port and the combustion chamber of each cylinder of the engine E.
Thereby, harmful substances (for example, NOx) contained in the exhaust gas are reduced.

On the other hand, in a region where the engine load is low and the engine speed is low, that is, during idling, in order to stabilize the combustion of the air-fuel mixture in the combustion chamber of the engine E, the EGR gas into each cylinder of the engine E (EGR cut).
In addition, when the driver depresses the accelerator pedal and wants to maximize the output of the engine E or at the time of acceleration traveling, the EGR gas is introduced into the combustion chamber of each cylinder of the engine E. In order to avoid a decrease in output, the introduction of EGR gas into the combustion chamber of each cylinder of the engine E is stopped (EGR cut).
At the time of the EGR cut as described above, the determination result in step S11 of FIG. 4 is Yes, and the fully closed control for returning the first and third valves 11 and 13 of the flow control valves 1 and 3 to the fully closed position is performed. Moreover, the determination result of step S21 of FIG. 5 becomes Yes, and the fully closed control which returns the 2nd, 4th valves 12 and 14 of the flow control valves 2 and 4 to a fully open position is implemented.

In this case, as shown in FIGS. 6 and 7, the first and third motor drive circuits are used to generate the closed motor torque of the first and third valves 11 and 13 in the motor M of the electric actuator 5. The minimum value of drive DUTY (DUTY = -100%) is given.
When DUTY = -100% is given from the ECU 20 to the first and third motor drive circuits, electric power (motor drive current or motor applied voltage) corresponding to DUTY = -100% is supplied to the armature coil of the motor M. Then, the motor driving current to the side of closing the first and third valves 11 and 13 flows through the armature coil of the motor M (step S13).
Thus, the first and third valves 11 and 13 are moved to the fully closed position side (fully closed operation) using the closed motor torque of the motor M. At this time, as shown in FIG. 6, when the first and third valves 11 and 13 are closed, the motor M's closing side motor torque is added to the spring force of the first and third springs SP. The closing side motor torque becomes a torque that assists the closing side of the first and third valves 11 and 13.

Further, in order to cause the motor M of the electric actuator 6 to generate the open side motor torque of the second and fourth valves 12 and 14, the minimum value of the drive DUTY (DUTY = −100%) in the second and fourth motor drive circuits. give.
When DUTY = -100% is given from the ECU 20 to the second and fourth motor drive circuits, power corresponding to DUTY = -100% (motor drive current or motor applied voltage) is supplied to the armature coil of the motor M. Then, the motor drive current to the side where the second and fourth valves 12 and 14 are opened flows through the armature coil of the motor M (step S23).
Accordingly, the second and fourth valves 12 and 14 are operated to the fully open position side (fully open operation) using the open side motor torque of the motor M. At this time, when the second and fourth valves 12 and 14 are opened, the opening motor torque of the motor M is added to the spring force of the second and fourth springs. The torque assists the opening side of the fourth valves 12 and 14.

Next, it is determined (determined) whether or not the actual opening (actual valve position) of the first and third valves 11 and 13 has reached a predetermined position (step S14). If this determination result is No, the process returns to the determination process of step S11.
Here, the predetermined position is the opening degree of the front (+ side) by a predetermined distance (predetermined rotation angle) from the fully closed position (θ = 0 (deg)) of the first and third valves 11 and 13. (Valve position).
On the other hand, it is determined (determined) whether or not the actual opening (actual valve position) of the second and fourth valves 12 and 14 has reached a predetermined position (step S24). If this determination result is No, the process returns to the determination process of step S21.
Here, the predetermined position is an opening (− side) in front of the second and fourth valves 12 and 14 by a predetermined distance (a predetermined rotation angle) from the fully opened position (θ = 70 to 80 (deg)). Degree (valve position).

When the determination result in step S14 is Yes, the drive DUTY values for the first and third motor drive circuits are set to the first and third valves toward the fully closed side by the set torque of the first and third springs SP. The setting value (DUTY = + β%) of the drive duty that can reduce the body return speed is set.
Specifically, the drive DUTY value given to the first and third motor drive circuits is a fully closed hold DUTY value (DUTY = + β%) that can hold the first and third valves 11 and 13 in the fully closed position. ) And this DUTY = + β% is given to the first and third motor drive circuits (duty value setting means: step S15). Thereafter, the control routine of FIG. 4 is exited. That is, the process returns to START of the control routine of FIG.

If the determination result in step S24 is Yes, the drive DUTY values for the second and fourth motor drive circuits are returned to the first and third valve bodies to the fully open side by the set torque of the second and fourth springs. The set value (DUTY = + β%) of the drive duty that can reduce the speed is set. .
Specifically, the drive DUTY value given to the second and fourth motor drive circuits is the fully closed hold DUTY value (DUTY = + β%) that can hold the second and fourth valves 12 and 14 in the fully closed position. ) And this DUTY = + β% is given to the second and fourth motor drive circuits (duty value setting means: step S25). Thereafter, the control routine of FIG. 5 is exited. That is, the process returns to START of the control routine of FIG.

As a result, the first and third valves 11 and 13 of the flow control valves 1 and 3 are electrically driven and biased toward the valve closing side, and the first and third flow paths 21 and 23 are closed. On the other hand, the second and fourth valves 12 and 14 of the flow control valves 2 and 4 are electrically driven and urged toward the valve opening side to open the second and fourth flow paths 22 and 24.
At this time, in the flow control valves 1 and 3, the sliding portion of the seal ring 36 fitted in the seal ring groove 35 of the first and third valves 11 and 13 causes the tension (elasticity) in the diameter increasing direction of the seal ring itself. Due to the deformation force), the sliding portion of the seal ring 36 comes into close contact with the valve seat surface of the nozzle 37.
Therefore, the gap between the outer peripheral end surfaces of the first and third valves 11 and 13 and the inner peripheral surface of the nozzle 37 is completely sealed. That is, the first and third flow paths 21 and 23 are completely closed. Thereby, the EGR gas is not mixed into clean intake air (fresh air) that has passed through the air cleaner 8.

[Effect of Example 1]
As described above, in the EGR valve control apparatus that controls the opening and closing of the flow control valves 1 and 3 of the present embodiment, the first and third valves 11 and 13 are moved to the fully closed position during the fully closed control. The drive DUTY value given to the third motor drive circuit is a set value of the drive DUTY that can decelerate the first and third valve body return speeds to the fully closed side by the set torque of the first and third springs SP ( DUTY = + β%) and this DUTY = + β% is provided to the first and third motor drive circuits.
Specifically, by fixing the first and third valves 11 and 13 to a fully closed holding DUTY value (DUTY = + β%) that can be held in the fully closed position, the “spring force shown in FIG. In the section for decelerating the return speed due to "As shown in FIG. 7, when the vicinity of the fully closed position is reached, the power supply to the motor M is limited by the fully closed hold DUTY." The first and third valve body return speeds are not decelerated. As a result, the motor drive current flowing through the inner conductor (armature coil) of the motor M can be reduced as compared with the prior art, and the temperature of each part of the motor can be prevented from exceeding the overheat limit temperature.

On the other hand, in the EGR valve control apparatus that controls the opening and closing of the flow rate control valves 2 and 4 so as to interlock with the flow rate control valves 1 and 3 of the present embodiment, the second and fourth valves 12 and 14 are fully opened to operate to the fully open position. During control, the drive DUTY value for the second and fourth motor drive circuits is set to the drive DUTY capable of decelerating the first and third valve body return speeds to the fully open side by the set torque of the second and fourth springs. The setting value (DUTY = + β%) is set, and this DUTY = + β% is provided to the second and fourth motor drive circuits.
Specifically, by fixing the second and fourth valves 12 and 14 to a fully closed holding DUTY value (DUTY = + β%) that can hold the second and fourth valves 12 and 14 in the fully closed position, similarly, the inner conductor of the motor M The motor drive current flowing through the (armature coil) can be reduced as compared with the prior art, and the temperature of each part of the motor can be prevented from exceeding the overheat limit temperature.

As a result, the electric power (motor drive current value) supplied to the inner conductor (armature coil) of the motor corresponds to the DUTY value of the PWM signal for the first to fourth motor drive circuits as shown in FIG. The occurrence of a problem that the temperature of each part of the motor M exceeds the overheat limit temperature (heat-resistant temperature of each part of the motor) is limited to a set value or less.
Accordingly, it is possible to prevent a motor failure and a decrease in the durability of the motor due to the temperature of each part of the motor M exceeding the overheat limit temperature, so that each part of the motor M can be protected.

Here, as a problem due to overheating of each part of the motor M, for example, if the armature coil generates heat and the heat is melted by the synthetic resin brush holder, the spring force of the brush spring is weakened, and the armature commutator The first and second brushes do not effectively come into contact with each other, and the internal conductor (armature coil) of the motor M cannot be energized. That is, a failure that the motor M does not move occurs.
Further, due to the heat generated in each part of the motor M, there is a possibility that the lubricating oil may be scattered in the motor yoke from the metal bush that supports the motor shaft. As a result, the lubrication between the metal bush and the motor shaft may be poor and may be seized. That is, a failure that the motor M does not move occurs.
Therefore, an EGR valve control device that performs valve opening control for controlling the valve positions of the first to fourth valves 11 to 14 of the flow control valves 1 to 4 based on the operating state of the engine E as in the present embodiment. Thus, it is possible to realize valve opening control with robustness (reliability and durability with respect to measures for preventing overheating of each part of the motor).

[Modification]
In this embodiment, flow control valves (EGR control valves) 1 and 3, flow control valves (intake throttle valves, intake control valves) 3, and the like are controlled by the valve (open / close) control device of the present invention. Although a flow control valve (exhaust throttle valve, exhaust control valve) 4 is employed, a low temperature exhaust gas communicating with the outlet side of the EGR cooler as a fluid control valve controlled to be opened and closed by the valve (open / close) control device of the present invention Exhaust gas flow path switching valve for switching between the flow path and a bypass flow path (high temperature exhaust gas flow path) that bypasses the EGR gas from the EGR cooler, exhaust gas flow rate installed in the exhaust pipe of the engine (turbine housing of the turbocharger) A pressure) control valve may be employed.

In addition, as the intake control valve, a tumble control valve, a swirl control valve, an intake flow control valve, an intake pressure control valve, a flow path switching valve, an intake throttle valve, and the like are conceivable.
Further, examples of the exhaust control valve include a waste gate valve, a scroll switching valve, an exhaust flow control valve, an exhaust pressure control valve, an exhaust switching valve, and an exhaust throttle valve.
In the present embodiment, the first and third springs that urge the first and third valves 11 and 13 in the valve closing (fully closed) direction are used as the fluid control valves used in the valve (opening and closing) control device of the present invention. Second and fourth springs having SP and urging the flow control valves 1 and 3 and the second and fourth valves 12 and 14 used as an EGR control valve having a normally fully closed structure in the valve opening (full opening) direction. Are applied to the flow control valves 2 and 4 used as intake and exhaust throttle valves of a normally fully open structure, but the fluid control valve used in the present invention is the flow control valve 1 or the flow control valve 3. The present invention may be applied to the flow control valve 2 or the flow control valve 4.

  The fluid control valve used in the valve (open / close) control device of the present invention may be applied only to the flow control valve 1. The fluid control valve used in the valve (opening / closing) control device of the present invention may be applied only to the flow control valve 2. Further, the fluid control valve used in the valve (opening / closing) control device of the present invention may be applied only to the flow control valve 3. The fluid control valve used in the valve (opening / closing) control device of the present invention may be applied only to the flow control valve 4. Further, the fluid control valve used in the valve (opening / closing) control device of the present invention may be applied only to the flow control valves 1 and 2. Further, the fluid control valve used in the valve (open / close) control device of the present invention may be applied only to the flow control valves 3 and 4.

In addition, the fluid control valve used in the valve (open / close) control device of the present invention is a first to fourth valve 11 that opens and closes (changes the cross-sectional area of the flow path) the flow path communicating with the cylinder of the diesel engine. In addition to the fluid control valve having ˜14, the present invention may be applied to a fluid control valve having a valve that opens and closes (changes the channel cross-sectional area of the channel) communicating with the cylinder of the gasoline engine.
In addition, the fluid control valve used in the valve (opening / closing) control device of the present invention is provided with an air flow path in the secondary air flow path pipe (housing) through which the secondary air supplied to the exhaust purification device of the internal combustion engine flows. You may apply to the secondary air control valve provided with the valve which opens and closes.
Further, the fluid control valve used in the valve (open / close) control device of the present invention is a valve that opens and closes an exhaust passage in an exhaust pipe (housing) through which exhaust gas (exhaust gas) discharged from the combustion chamber of the internal combustion engine flows. You may apply to exhaust control valves, such as the provided exhaust throttle valve and the flow control valves 1 and 3.

In addition, although a butterfly valve is employed as a valve constituting the valve body of the fluid control valve, a rotary valve such as a flap valve, a plate valve, or a rotary valve may be employed.
As an intake control valve which is an example of a fluid control valve, in addition to a flow control valve 2 used as an intake throttle valve (intake throttle valve), a tumble control valve, a swirl control valve, an intake pressure control valve, an intake flow A path switching valve or the like can be considered.
The exhaust control valve which is an example of the fluid control valve includes a waste flow control valve 1 and 3 used as an EGR control valve, a flow control valve 4 used as an exhaust throttle valve (exhaust throttle valve), and a waste control valve. A gate valve, a scroll switching valve, an exhaust pressure control valve, an exhaust flow path switching valve, and the like are conceivable.

M motor SP 1st, 3rd spring 1 Flow control valve (EGR control valve)
2 Flow control valves (intake throttle valve, intake throttle valve)
3 Flow control valve (EGR control valve)
4 Flow control valve (exhaust throttle valve, exhaust throttle valve)
11 First valve (EGR valve)
12 Second valve (throttle valve)
13 Third valve (EGR valve)
14 Fourth valve (throttle valve)

Claims (7)

(A) valves (11-14) for opening and closing flow paths (21-24) communicating with the cylinders of the internal combustion engine (E);
(B) an actuator (5, 6) having a motor (M) for generating power for driving the valves (11-14) and transmitting the power of the motor (M) to the valves (11-14); (C) Define the fully closed position or fully open position of the valve (11-14), and also toward the output side (19) of the actuator (5, 6) and the closing side or opening side of the valve (11-14). A fixed stopper (17) for restricting movement of the
(D) a spring (SP) for urging the output (19) of the actuator (5, 6) in a direction in which the valve (11-14) is pressed against the fixed stopper (17); ) A sensor (18) for detecting position information of the valve (11-14);
(F) Control for the motor (M) so that there is no deviation between the target valve position set in accordance with the operating condition of the internal combustion engine (E) and the actual valve position detected by the sensor (18). A valve control device comprising a control unit (20) for feedback control of the signal;
When the control unit (20) operates the valve (11-14) to the fully closed position or the fully open position, the control unit (20) sends a control signal for the motor (M) to the fully closed position by the set torque of the spring (SP). A valve control device comprising duty value setting means for setting a return speed to the side or fully open side to a duty value that can be decelerated. The valve control device according to claim 1,
The control unit (20)
When the duty value of the control signal for the motor (M) is set,
A valve control device that supplies electric power capable of holding the valve (11-14) to the fully closed position or the fully open position to an internal conductor of the motor (M). In the valve control device according to claim 1 or 2,
The output portions of the actuators (5, 6) include an output gear (19) that rotates by receiving the power of the motor (M), and an output shaft (15, 16) that is connected to the output gear (19) so as to be integrally rotatable. The valve control apparatus characterized by having. In the valve control device according to claim 3,
The fixed stopper (17) has a first restricting portion that restricts further operation of the output gear (19) in the valve closing direction when the valves (11, 13) are fully closed.
When the valve (11, 13) is fully closed, the output gear (19) or the output shaft (15) is brought into contact with the first restricting portion to be locked. A valve control device characterized by comprising: In the valve control device according to claim 3 or 4,
The fixed stopper has a second restricting portion that restricts further operation of the output gear in the valve opening direction when the valve (12, 14) is fully opened.
The output gear or the output shaft (16) has a second locking portion that contacts and locks against the second restricting portion when the valve (12, 14) is fully opened. A characteristic valve control device. The valve control device according to any one of claims 1 to 5,
The valve is
When energization of the motor (M) is stopped, the first flow path (21) corresponding to the flow path through which EGR gas that is part of the exhaust gas of the internal combustion engine (E) flows is fully closed, and the motor ( A valve body (11) of a normally closed type first flow control valve (1) that increases the cross-sectional area of the first flow path (21) with an increase in power to M),
When the energization of the motor (M) is stopped, the second flow path (22) corresponding to the flow path through which the intake air of the internal combustion engine (E) flows is fully opened to increase the power to the motor (M). The valve control device is a valve element (12) of a normally open type second flow rate control valve (2) that decreases the cross-sectional area of the second flow channel (22) along with the first flow rate control valve (2). . In the valve control device according to any one of claims 1 to 6,
The valve is
When energization of the motor (M) is stopped, the third flow path (23) corresponding to the flow path through which EGR gas that is part of the exhaust gas of the internal combustion engine (E) flows is fully closed, and the motor ( A valve body (13) of a normally closed third flow control valve (3) that increases the cross-sectional area of the third flow path (23) with an increase in power to M),
When the energization of the motor (M) is stopped, the fourth flow path (24) corresponding to the flow path through which the remainder of the exhaust gas of the internal combustion engine (E) flows is fully opened, and the electric power to the motor (M) A valve element (14) of a normally open type fourth flow rate control valve (4) that decreases the cross-sectional area of the fourth flow path (24) as the flow rate increases. Control device.

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