JP6728023B2 - Intake switching valve - Google Patents

Description

The present invention relates to an intake switching valve used for switching intake air introduced into an intake passage of an engine between low temperature air and high temperature air, and more specifically, switching between low temperature air and high temperature air. The present invention relates to an intake switching valve that drives a valve body with a motor.

As an intake switching valve, for example, Patent Document 1 discloses an intake air temperature control device provided with a hot air valve (valve body) that opens and closes each intake port of outside air (low temperature air) and warm air (high temperature air). .. In this intake air temperature control device, the intake air introduced into the intake chamber connected to the engine is switched between the outside air and the warm air by rotating the hot air valve. That is, warm air is introduced by opening the hot air valve. Then, under a certain specific condition (for example, at the time of full load operation), the hot air valve is forcibly set to the outside air introduction state regardless of the temperature of the intake air.

JP, 2000-234568, A

However, when the valve element is driven (rotated) by the motor, the valve element is kept fully open during high temperature air introduction even when not under full load operation, so the influence of the differential pressure across the valve element (pressure fluctuation in the intake passage) In consideration of the above, the duty of energizing the motor is set to be large (surplus). Therefore, the load on the motor becomes excessive, which may increase power consumption and damage the motor. Further, when the required output value of the engine becomes large during the introduction of the high temperature air, it is desired to introduce the low temperature air early in order to prevent the output from decreasing.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an intake switching valve that can prevent an excessive load on a motor.

One embodiment of the present invention made to solve the above problems is a low temperature air passage portion for introducing low temperature air into an intake passage connected to an engine, and a high temperature air passage for introducing high temperature air into the intake passage. Section, a valve body that opens and closes the low temperature air passage section and the high temperature air passage section, a motor that rotationally drives the valve body, and a control section that controls the opening degree of the valve body by duty-controlling the motor. In the intake switching valve having, the control unit arranges the valve element in a fully open position where the low temperature air passage section is closed and the high temperature air passage section is opened by the valve body when a request for introducing high temperature air is made. The full-open holding duty, which is the energizing duty that generates the torque required to hold the motor in the full-open position, which is calculated based on the amount of intake air taken into the engine. It is characterized by doing.

In this intake switching valve, the control unit calculates the fully open holding duty for holding the valve element at the fully open position based on the intake air amount (mass flow rate) when a request for introducing hot air is made. Specifically, the full-open holding duty is the minimum duty required for holding the full-open position calculated based on the intake air amount. That is, the full-open holding duty is the minimum energization duty required for the motor to generate the torque for holding the valve element in the full-open position in accordance with the intake air amount. Therefore, the energization duty to the motor does not become large (excessive), so that it is possible to prevent the load of the motor from becoming excessive. As a result, it is possible to reduce power consumption and prevent damage to the motor.

In the above intake switching valve, the control unit may set the full-open holding duty to a predetermined duty smaller than the minimum duty when the output required value of the engine becomes larger than a predetermined first predetermined value. desirable.

By doing so, when the output demand value of the engine becomes larger than the first predetermined value, that is, when the output demand becomes large and the required intake air amount increases and the full-open holding duty increases, the control unit Thus, the full open holding duty is set to a predetermined duty smaller than the minimum duty. Therefore, the output (torque) of the motor is reduced, and the valve element cannot be held at the fully open position, and the valve element rotates toward the valve closing side.

As a result, the low-temperature air passage portion is also opened, so that low-temperature air is introduced into the intake passage from the low-temperature air passage portion in addition to the high-temperature air, so that the required intake air amount according to the output request can be secured. .. That is, the maximum amount of high temperature air can be introduced while ensuring the required intake air amount. Moreover, since the energization duty to the motor is reduced, the load on the motor is reduced. As described above, when the output demand value of the engine becomes large during the introduction of the high temperature air, the load on the motor is reduced and the low temperature air is introduced at an early stage to secure the necessary intake air amount. Therefore, it is possible to prevent the output from decreasing.

Further, in the above intake switching valve, the control unit gradually moves the fully open position of the valve element to the valve closing side when the fully open holding duty is equal to or higher than a predetermined value and is in a high duty state for a predetermined time. Correction may be performed.
It should be noted that it is preferable to set a different predetermined time for the duty value as the predetermined time for determining the high duty state. For example, the determination time (predetermined time) may be set shorter as the duty value increases.

When the output demand of the engine increases and the required intake air amount increases, the full-open holding duty increases due to the influence of the differential pressure across the intake switching valve. Therefore, an excessive load may be applied to the motor. Therefore, in this intake switching valve, when the full-open holding duty is equal to or higher than a predetermined value and becomes a high duty state that continues for a predetermined time, the control unit performs full-open opening correction for moving the full-open position of the valve element to the valve closing side. Specifically, the fully opened position of the valve body is gradually moved to the valve closing side so that the fully opened holding duty becomes equal to or less than the minimum duty. Therefore, the valve body gradually rotates toward the valve closing side, and the full open holding duty becomes smaller.

Finally, since the energization duty to the motor becomes the minimum duty or less, the load on the motor is reduced. Further, since the valve body is rotated toward the valve closing side to open the low temperature air passage portion, low temperature air is introduced into the intake passage from the low temperature air passage portion in addition to the high temperature air. It is possible to secure a sufficient intake air amount. In this way, when the output required value of the engine becomes large and the high duty state is reached during the introduction of high temperature air, the opening is gradually closed and the energization duty is reduced, so the load on the motor is reduced. At the same time, low-temperature air can be introduced at an early stage to secure a required intake air amount, so that output reduction can be prevented.

In this case, when the controller is performing the full-opening degree correction, when the high-duty state is lost and the required output value of the engine becomes smaller than the first predetermined value, the full-opening degree is reduced. It is preferable to cancel the correction and gradually move the fully open position of the valve element to the valve opening side.

By doing so, when the full-opening degree correction is being performed, the high output duty state is lost and the engine output request value becomes smaller than the first predetermined value, that is, the output request becomes smaller and the required intake air amount becomes smaller. When is decreased, the control unit cancels the correction of the fully opened position of the valve body, and gradually moves the fully opened position of the valve body to the valve opening side. As a result, the fully open position of the valve element gradually returns to the position before the full opening degree correction. Therefore, the valve body rotates to the valve opening side, and finally returns to the normal fully open position (the position where the low temperature air passage part is fully closed), so that the high temperature air is sufficiently supplied to the intake passage. Can be introduced.

In the above intake switching valve, it is preferable that the control unit fully closes the valve body when the required output value of the engine exceeds a second predetermined value that is larger than the first predetermined value.

By doing so, when the output demand value of the engine becomes even larger, the control unit fully closes the valve element, so that the introduction of the high temperature air is stopped and the low temperature air is introduced early. Therefore, it is possible to secure the amount of intake air according to the output demand, improve the oxygen concentration with the introduction of the low temperature air, and prevent the output from decreasing.

Further, in the above intake switching valve, the control unit may correct the full-open holding duty based on the temperature of the motor.
The temperature of the motor used to correct the full-open holding duty may be an estimated value instead of an actually measured value.

By doing so, the full-open holding duty can be accurately calculated in accordance with the change in the motor output (torque) due to the change in the motor temperature. Therefore, even when the temperature of the motor changes from the normal time, it is possible to reliably maintain the fully open state and prevent the energization duty to the motor from becoming large (excessive). As a result, it is possible to reliably reduce the power consumption while maintaining the fully opened state.

The intake switching valve according to the present invention can prevent the load on the motor from becoming excessive.

It is a schematic structure figure showing an engine system. It is an external appearance perspective view of an intake switching valve. It is a front view of an intake switching valve. It is a rear view of an intake switching valve. It is an AA sectional view of Drawing 3, and is a figure showing the state where the valve body was arranged at the fully closed position. It is an AA sectional view of Drawing 3, and is a figure showing the state where the valve element was arranged at the full open position. It is a figure which shows the control flowchart in 1st Embodiment. It is a figure which shows a full open holding duty calculation map. It is a figure which shows the control time chart in 1st Embodiment. FIG. 6 is a diagram showing a full-open holding duty calculation map when the full-open holding duty is corrected by the motor temperature. It is a figure which shows the control flowchart in the case of correcting a full open holding duty by motor temperature. It is a figure which shows the control flowchart in 2nd Embodiment. It is a figure which shows the full open holding duty calculation map in 2nd Embodiment. FIG. 4 is a cross-sectional view taken along the line AA of FIG. 3, showing a state in which the valve body is rotated from the fully open position toward the fully closed position. It is a figure which shows the control flowchart in the modification of 2nd Embodiment. It is a figure which shows a full open holding duty calculation map at the time of correcting a full open holding duty by a motor temperature in 2nd Embodiment. It is a figure which shows the control flowchart in 3rd Embodiment. It is a figure which shows the control flowchart in 3rd Embodiment. It is a figure which shows the map which calculates the predetermined time with respect to each duty value for determining a high duty state. It is a figure which shows the control time chart in 3rd Embodiment.

<First Embodiment>
First, the first embodiment will be described. In the following description, first, the engine system 1 having the intake switching valve 21 of the present embodiment will be described, and then the intake switching valve 21 of the present embodiment will be described.

As shown in FIG. 1, the engine system 1 includes an intake passage 12 that is connected to the engine 11 and that introduces intake air into the engine 11, and an exhaust passage 13 that guides exhaust gas from the engine 11. The intake passage 12 is provided with an air cleaner 14, an electronic throttle device 15 and an intake manifold 16 in this order from the upstream side (left side in FIG. 1) in the flow direction of intake air. Further, the exhaust passage 13 is provided with a catalytic converter 17 for purifying the exhaust.

Further, the engine system 1 selectively causes cool air (low temperature air, outside air), hot air (high temperature air), or mixed air of cool air and hot air to flow to the downstream side of the intake passage 12 so as to intake air temperature. The intake air temperature control device 18 for controlling the The intake air temperature control device 18 includes a shroud 19 for collecting hot air around the exhaust passage 13 (exhaust manifold), and hot air for introducing the hot air collected by the shroud 19 into the intake passage 12 upstream of the air cleaner 14. An introduction passage 20 and an intake switching valve 21 provided at a connection portion between the intake passage 12 and the hot air introduction passage 20 on the upstream side of the air cleaner 14 are provided. To the intake switching valve 21, one end of the hot air introducing passage 20 and an intake inlet 22 for introducing cool air into the intake passage 12 are connected. The intake switching valve 21 will be described later.

In addition, the engine system 1 cools the EGR passage (exhaust gas recirculation passage) 23 that recirculates a part of the exhaust gas discharged to the exhaust passage 13 as the EGR gas (exhaust gas recirculation gas) to the intake passage 12, and the EGR gas. An EGR cooler (exhaust gas recirculation cooler) 24 and an EGR valve (exhaust gas recirculation valve) 25 for adjusting the flow rate of EGR gas in the EGR passage 23 are provided. The engine system 1 also has a blow-by gas passage 26 and a fresh air introduction passage 27 formed between the engine 11 and the intake passage 12. Further, the engine system 1 has an air flow meter 28 that detects an intake air amount (mass flow rate) in the intake passage 12 upstream of the electronic throttle device 15.

Next, the intake switching valve 21 of this embodiment will be described. As shown in FIGS. 2 to 6, the intake switching valve 21 includes an intake passage portion 31, a cool air passage portion 32 (an example of a low temperature air passage portion), a hot air passage portion 33 (an example of a high temperature air passage portion), It has a shaft 34, a valve body 35, a motor 36, a controller 37, and the like.

The intake passage portion 31 communicates with the intake passage 12 (see FIG. 1) via the air cleaner 14 and the air flow meter 28 (see FIG. 1). As shown in FIG. 3, the intake passage portion 31 has a substantially rectangular cross section when viewed from the downstream side (the right side in FIG. 5) in the flow direction of the intake air (the corners are arcuate (R-shaped)). (Rectangle formed in).

As shown in FIG. 5, the cool air passage portion 32 is formed on the upstream side (left side in FIG. 5) of the intake passage portion 31 in the cool air flow direction. The cool air passage portion 32 has a substantially rectangular cross section as viewed from the upstream side (left side in FIG. 5) in the flow direction of the cool air, as shown in FIG. The cool air passage portion 32 is a passage for introducing the cool air introduced from the intake inlet 22 (see FIG. 1) into the intake passage 12 via the intake passage portion 31. The cool air passage portion 32 is formed so as to be coaxial with the intake passage portion 31.

As shown in FIG. 5, the hot air passage portion 33 is formed at a position upstream (lower side in FIG. 5) of the intake passage portion 31 in the hot air flow direction. The hot air passage portion 33 is formed, for example, in a circular outer shape in a cross section when viewed in the hot air flow direction. The hot air passage portion 33 is a passage for introducing hot air introduced from the hot air introduction passage 20 (see FIG. 1) into the intake passage 12 via the intake passage portion 31. The hot air passage portion 33 is formed such that the axial direction of the hot air passage portion 33 intersects with the axial direction of the intake passage portion 31.

As shown in FIG. 5, the shaft 34 is provided near the connecting portion between the cool air passage portion 32 and the hot air passage portion 33. The shaft 34 is arranged such that the axial direction of the shaft 34 is orthogonal to the axial direction of the cool air passage portion 32.

The valve element 35 is integrated with the shaft 34, and is rotated about the shaft 34 by a motor 36 via a gear (not shown). The valve element 35 is formed in a substantially rectangular flat plate shape.

The motor 36 is connected to the shaft 34 via a gear (not shown). The motor 36 rotates (drives) the valve element 35 by rotating around the shaft 34 via a gear. In this embodiment, a DC motor is used as the motor 36.

The control unit 37 is an ECU that includes, for example, a central processing unit (CPU), various memories, and controls the entire intake switching valve 21 including the motor 36. The output signals of various sensors provided in the engine system 1 are input to the control unit 37, and the control unit 37 controls the opening degree of the intake switching valve 21 based on those signals. Further, the control unit 37 stores a fully opened holding duty calculation map (see FIG. 8) described later.

In the intake switching valve 21 configured as described above, the passage that communicates with the intake passage 12 is formed in the cool air passage portion 32 or the hot air passage portion 33 by rotating the shaft 34 and rotating the valve body 35 by the motor 36. Switch. Then, in this way, the intake switching valve 21 switches the intake air introduced into the intake passage 12 between cool air and hot air.

Specifically, in the intake switching valve 21, the valve element 35 can be switched between the fully closed position (cool air introduction position) shown in FIG. 5 and the fully opened position (hot air introduction position) shown in FIG. It can be held in any intermediate position between the fully closed and fully open positions. Here, as shown in FIG. 5, in the fully closed position, the cool air passage portion 32 communicates with the intake passage 12 via the intake passage portion 31, and the hot air passage portion 33 blocks the intake passage 12 (intake passage portion 31). To be done. Further, in the fully open position shown in FIG. 6, the cool air passage portion 32 is blocked from the intake passage 12 (intake passage portion 31 ), and the hot air passage portion 33 communicates with the intake passage 12 via the intake passage portion 31.

When the cool air is introduced, the valve body 35 is arranged at the fully closed position shown in FIG. 5, so that the hot air from the hot air passage portion 33 (the hot air introduction passage 20) is shut off and the cool air passage portion 32 (the intake inlet 22 ) Is introduced into the intake passage 12 after the air cleaner 14. On the other hand, when hot air is introduced, the valve body 35 is arranged at the fully open position shown in FIG. 6 so that the cool air from the cool air passage portion 32 is blocked and the hot air from the hot air passage portion 33 is sucked into the intake passage 12 after the air cleaner 14. Introduce to. Further, when the mixed air is introduced, the valve body 35 is held at an arbitrary intermediate position between the fully closed position and the fully open position, so that the cool air from the cool air passage portion 32 and the hot air from the hot air passage portion 33 are separated from each other. The mixed air is introduced into the intake passage 12 after the air cleaner 14.

Such control of the opening degree of the intake switching valve 21 is performed by the control unit 37 performing duty control of the motor 36 based on the operating state of the engine 11. Specifically, the control unit 37 executes the control based on the control flowchart shown in FIG. 7. That is, the control unit 37 first determines whether or not there is a request to introduce hot air, that is, a high temperature intake request. Specifically, the control unit 37 determines whether or not the high temperature intake flag HAflg is ON (step S1). When the high temperature intake flag HAflg is ON (step S1: YES), the opening command value for the intake switching valve 21 is fully opened (step S2), and the valve element 35 of the intake switching valve 21 is arranged at the fully open position. It is determined whether or not it is open (step S3). In this full open determination, it is determined whether the difference (deviation) between the command value (opening) and the actual opening of the intake switching valve 21 is smaller than a predetermined value. That is, when the difference (deviation) between the command value (opening) and the actual opening of the intake switching valve 21 is smaller than a predetermined value, it is determined that the valve is fully open, and when it is larger than the predetermined value, it is fully open. It is determined that there is no. It should be noted that the predetermined value for performing such a full-open determination may be set to 1° or less (for example, 0.5°).

If the control unit 37 determines that the intake switching valve 21 is fully open in the fully open determination (step S3: YES), the control unit 37 acquires the intake air amount (mass flow rate) from the output signal of the air flow meter 28 (step S3). S5). Next, the control unit 37 calculates the full open holding duty to be applied to the motor 36 from the acquired intake air amount using the full open holding duty calculation map shown in FIG. 8 (step S6), and performs the fixed duty control on the motor 36. Is controlled (step S7). That is, the duty of the motor 36 is controlled by the full-open holding duty calculated in step S6.

As shown in FIG. 8, the full-open holding duty calculation map is for calculating the minimum required duty (DUTY) for holding the valve body 35 at the fully open position based on the intake air amount (mass flow rate). Is a map of. This full-open holding duty calculation map is adjusted to the optimum one by experiments for each specification of the engine 11. The broken line in FIG. 8 indicates the energization duty when the conventional fixed duty control is performed.

In this way, the valve body 35 is arranged at the fully open position shown in FIG. 6, the cool air from the cool air passage portion 32 is shut off, and the hot air from the hot air passage portion 33 is introduced into the intake passage 12 after the air cleaner 14. .. The full-open holding duty for the motor 36 at this time is the energization duty (minimum duty) required for the motor 36 to generate the minimum torque for holding the valve body 35 at the full-open position. .. Therefore, the energization duty to the motor 36 does not become large (excessive), so that it is possible to prevent the load of the motor 36 from becoming excessive. As a result, power consumption can be reduced and damage to the motor 36 can be prevented.

On the other hand, when the high temperature intake flag HAflg is OFF (step S1: NO), the controller 37 fully closes the opening command value for the intake switching valve 21 (step S8), and executes the opening feedback control. Yes (step S9). As a result, the valve body 35 is arranged at the fully closed position shown in FIG. 5, the hot air from the hot air passage portion 33 (hot air introduction passage 20) is blocked, and the cool air from the cool air passage portion 32 (intake inlet 22) is cooled by the air cleaner. It is introduced into the intake passage 12 after 14.

By executing the control based on the above control flowchart, for example, the control represented by the control time chart as shown in FIG. 9 is executed. That is, as shown in FIG. 9, when the high temperature intake flag HAflg is turned on at time T1, the opening command value is fully opened and the opening feedback control is executed. As a result, the actual opening of the intake switching valve 21 approaches full opening. When the actual opening is fully opened at time T2, the fixed duty control is performed with the full open holding duty (DUTY) calculated by the full open holding duty calculation map shown in FIG. 8 based on the intake air amount (mass flow rate). Be implemented. After that, when the intake air amount decreases after time T3, the full-open holding duty decreases accordingly, and the fixed duty control is performed with the full-open holding duty according to the intake air amount. As a result, it is possible to maintain the intake switching valve 21 in the fully open state with an energization duty smaller than the conventional full-open holding duty (broken line).

Here, the output of the motor 36 changes depending on the temperature of the motor 36. That is, as the temperature of the motor 36 increases, the output of the motor 36 decreases, and when the temperature of the motor 36 decreases, the output of the motor 36 increases. Therefore, if the fully open holding duty is determined only from the intake air amount as described above, it becomes impossible to hold the valve body 35 in the fully open position when the temperature of the motor 36 becomes high, or when the temperature of the motor 36 becomes low, it becomes more than necessary. The energization duty may be applied to the motor 36.

Therefore, it is preferable that the control unit 37 obtains the temperature of the motor 36 in addition to the intake air amount and corrects the full-open holding duty based on the temperature of the motor 36. The temperature of the motor 36 can be detected by attaching a temperature sensor to the motor 36, or can be estimated by the following equation.

T(t+Δt)
=T(t)+(R·I(t) ² −h(t)·S(T(t)−To(t))) Δt/M
The motor temperature T(0) at t=0 (when the ignition switch is turned on) is T(0)=Ti.
T(t): Motor temperature t: Time Δt: Time step I(t): Current R: Resistance of entire motor M: Thermal mass (heat capacity) of entire motor
Ti: initial temperature of motor S: surface area of motor To(t): ambient temperature h(t): heat transfer coefficient with atmosphere Ti: engine water temperature when ignition switch is ON

Here, the heat dissipation term “h(t)·S(T(t)−To(t))” is preferably calculated by the motor and the housing around the motor, but since the calculation becomes complicated, the motor It is supposed to be in the external atmosphere. Since To(t) and h(t) are unclear, the engine water temperature Tw(t), the outside air temperature Ta(t), and the vehicle speed spd(t) are estimated, and h(t) is calculated by multiple regression analysis. ) And To(t) are obtained as follows.
To(t)=a·Tw(t)+b·Ta(t)+c·spd(t)
h(t)=d·T(t−Δt)+e·To(t)+f·spd(t)
Note that a to d are constants, and the previous value is used only for the motor temperature.

When the temperature of the motor 36 is acquired (estimated) in this way, the control unit 37 stores the full-open holding duty calculation map shown in FIG. 10 instead of the full-open holding duty calculation map shown in FIG. As shown in FIG. 10, this map is for calculating the minimum duty required to hold the valve element 35 in the fully open position in consideration of not only the intake air amount (mass flow rate) but also the motor temperature. Is a map of. That is, the map shown in FIG. 8 is corrected according to the motor temperature. Specifically, as shown in FIG. 10, when the motor temperature is low, the full-open holding duty (DUTY) is corrected to be small, and when the motor temperature is high, the full-open holding duty (DUTY) is increased. Will be corrected. The map at room temperature shown in FIG. 10 corresponds to the map shown in FIG.

Then, the control unit 37 executes control based on the control flowchart shown in FIG. That is, the control unit 37 basically executes control based on the control flowchart shown in FIG. 7, but estimates the temperature of the motor 36 in addition to acquiring the intake air amount. Specifically, the temperature of the motor 36 is estimated using the above formula (step S4), and the intake air amount (mass flow rate) is acquired (step S5). The processing order of steps S4 and S5 may be reversed.

Then, the control unit 37 calculates the full open holding duty (DUTY) using the full open holding duty calculation map shown in FIG. 10 based on the temperature of the motor 36 and the intake air amount (step S6a), and performs the fixed duty control. The motor 36 is controlled (step S7). That is, the motor 36 is duty-controlled by the full-open holding duty calculated in step S6a.

As a result, when the motor temperature is high and the motor output is small, the full open holding duty is calculated to be larger than that at normal temperature. On the contrary, when the motor temperature is low and the motor output is high, the full-open holding duty is calculated to be smaller than that at normal temperature. Therefore, even when the motor temperature is high, the valve body 35 can be reliably held in the fully open position, and when the motor temperature is low, the energization duty more than necessary is not applied to the motor 36. Therefore, the power consumption can be further reduced.

As described above in detail, according to the intake switching valve 21 according to the present embodiment, the fully open holding duty for holding the valve body 35 at the fully open position is controlled by the control unit 37 at the time of requesting introduction of high temperature air. The minimum energization duty required for the motor 36 to generate the torque for holding the valve element 35 in the fully open position according to the intake air amount is set. Therefore, the energization duty to the motor 36 does not become large (excessive), so that it is possible to prevent the load of the motor from becoming excessive. As a result, power consumption can be reduced and damage to the motor 36 can be prevented.

<Second Embodiment>
Next, the second embodiment will be described. The same components as those in the first embodiment are designated by the same reference numerals, the description thereof will be omitted, and different points will be mainly described. The system configuration of this embodiment is the same as that of the first embodiment, but the content of the opening control of the intake switching valve 21 is different from that of the first embodiment. That is, when the output required value of the engine 11 becomes large, unlike the first embodiment, the control unit 37 sets the fully open holding duty to the minimum duty calculated according to the intake air amount (mass flow rate). Opening degree control is performed to limit the duty to a smaller value. Specifically, the control unit 37 executes the control based on the control flowchart shown in FIG.

Therefore, the control unit 37 stores the full-open holding duty calculation map shown in FIG. 13 instead of the full-open holding duty calculation map shown in FIG. As shown in FIG. 13, this map basically calculates the minimum duty (DUTY) required to hold the valve body 35 at the fully open position while basically calculating the intake air amount, In a region where is larger than the predetermined value B (first predetermined value), the map is for limiting to a predetermined duty smaller than the minimum duty. The predetermined value B (first predetermined value) may be set to B=30 g/s in the case of an engine having a displacement of about 1.3 L, for example. The predetermined value B increases as the displacement increases. The broken line in FIG. 13 shows the full-open holding duty calculation map of the first embodiment.

First, as shown in FIG. 12, the control unit 37 determines whether or not there is a request to introduce hot air, that is, a high temperature intake request. Specifically, the control unit 37 determines whether or not the high temperature intake flag HAflg is ON (step S10). When the high temperature intake flag HAflg is ON (step S10: YES), the controller 37 determines whether the output request value for the engine 11 is smaller than the predetermined value A (step S11).

Here, the output request value is preferably calculated by combining the load factor, the throttle opening, the intake air amount, the engine speed, and the like under a plurality of conditions. Since the air amount (mass flow rate) has a correlation, the required output value is determined by the intake air amount (mass flow rate). The predetermined value A (second predetermined value) may be set to A=60 g/s in the case of an engine with a displacement of about 1.3 L, for example. The predetermined value A increases as the displacement increases.

When the output request value is smaller than the predetermined value A (step S11: YES), the controller 37 fully opens the opening command value for the intake switching valve 21 (step S12), and the fully open flag is ON. It is determined whether or not (step S13). The fully open flag is OFF when the ignition switch is ON.

On the other hand, when the high temperature intake flag HAflg is OFF (step S10: NO), the controller 37 fully closes the opening command value for the intake switching valve 21 (step S25), and executes the opening feedback control. (Step S26), the fully open flag is turned off (step S27). As a result, the valve body 35 is arranged at the fully closed position shown in FIG. 5, the hot air from the hot air passage portion 33 (hot air introduction passage 20) is blocked, and the cool air from the cool air passage portion 32 (intake inlet 22) is cooled by the air cleaner. It is introduced into the intake passage 12 after 14.

Also, when the output request value is larger than the predetermined value A (step S11: NO), the controller 37 executes the processes of steps S25 to S27. As a result, when the required output value of the engine 11 becomes large and a large amount of intake air is required, the intake switching valve 21 is fully closed, so that the introduction of hot air is stopped and the cool air is introduced early. Thus, the intake air amount according to the output request can be secured, and the output reduction can be prevented.

When the full open flag is ON (step S13: YES), the control unit 37 uses the full open holding duty calculation map shown in FIG. 13 to determine the motor 36 based on the intake air amount (mass flow rate). The full-open holding duty (DUTY) applied to is calculated (step S15), and the motor 36 is controlled by the fixed duty control (step S16). That is, the duty of the motor 36 is controlled by the full open holding duty calculated in step S15.

As a result, when the required output value of the engine 11 becomes larger than the predetermined value B, the required intake air amount increases, and the full-open holding duty increases, the full-open holding duty becomes the predetermined duty smaller than the minimum duty. It Therefore, the output (torque) of the motor 36 decreases, and the valve body 35 cannot be held at the fully open position, and the valve body 35 rotates toward the valve closing side as shown in FIG. As a result, the cool air passage portion 32 is slightly opened, so that the cool air is introduced into the intake passage 12 from the cool air passage portion 32 in addition to the hot air, so that the required intake air amount according to the output request can be secured. ..

That is, the maximum amount of hot air can be introduced while ensuring the required intake air amount. Further, since the energization duty to the motor 36 is reduced, the load on the motor 36 is reduced. As described above, when the output required value of the engine 11 becomes large during the introduction of the hot air, the cool air is introduced in addition to the hot air while preventing the load on the motor 36 from becoming excessive. The quantity can be secured.

On the other hand, when the full open flag is OFF (step S13: NO), the control unit 37 performs the opening degree feedback control (step S20), and the valve body 35 of the intake switching valve 21 is set to the full open position. A full open determination is performed to determine whether or not they are arranged (step S21). In this full open determination, it is determined whether the difference (deviation) between the command value (opening) and the actual opening of the intake switching valve 21 is smaller than a predetermined value. That is, when the difference (deviation) between the command value (opening) and the actual opening of the intake switching valve 21 is smaller than a predetermined value, it is determined that the valve is fully open, and when it is larger than the predetermined value, it is fully open. It is determined that there is no. It should be noted that the predetermined value for performing such a full-open determination may be set to 1° or less (for example, 0.5°).

Then, when the control unit 37 determines in the fully open determination that the fully open state is obtained (step S21: YES), the fully open flag is turned on (step S22). On the other hand, when it is determined that the full opening is not completed (step S21: NO), the full opening flag is turned off (step S23).

As described above, according to the present embodiment, when the high temperature intake flag HAflg is ON and the required output value is smaller than the predetermined value A, the control unit 37 performs the opening degree feedback control to operate the intake switching valve 21. Once fully opened, fixed duty control is executed based on the map shown in FIG. Therefore, in the medium load region in which the required output value is larger than the predetermined value B and smaller than the predetermined value A, the energization duty to the motor 36 is set to the predetermined duty smaller than the minimum duty, and as a result, the valve body 35 is closed. The cool air passage portion 32 is also opened by rotating to, and cool air is introduced into the intake passage 12 from the cool air passage portion 32 in addition to the hot air. As a result, in the medium load region, it is possible to secure the required intake air amount while introducing the maximum amount of hot air while reducing the duty by energizing the motor 36 to reduce the load.

Further, in the high load region in which the high temperature intake flag HAflg is ON and the required output value is larger than the predetermined value A, the control unit 37 fully closes the intake switching valve 21. As a result, cool air is introduced into the intake passage 12 from the cool air passage portion 32, so that it is possible to secure an amount of intake air according to the output demand and to improve the oxygen concentration with the introduction of cool air. Output reduction can be prevented.

Here, when the high temperature intake flag HAflg is ON and the intake air amount (mass flow rate) is small, the valve body 35 is reliably maintained in the fully open position, and cool air is introduced into the intake passage 12. It is desirable to avoid. However, since the valve body 35 is held at the fully open position by the fixed duty control based on the map shown in FIG. 13, the opening degree of the valve body 35 is controlled in a timely manner, so the differential pressure across the intake switching valve 21 is controlled. There is a possibility that the valve element 35 may rotate toward the valve closing side due to a temporary change of

Therefore, in order to prevent the valve body 35 from rotating toward the valve closing side when the intake air amount (mass flow rate) is small, the control unit 37 performs fixed duty control or opens according to the output required value. It is preferable to select whether to perform feedback control once. Specifically, the control unit 37 may execute the control based on the control flowchart shown in FIG. In the control flow chart shown in FIG. 15, steps that perform the same processing as those in the control flow chart shown in FIG. 12 will be assigned the same reference numerals and description thereof will be omitted as appropriate.

That is, as shown in FIG. 15, when the control unit 37 determines that the fully open flag is ON (step S13: YES), the control unit 37 determines whether the output request value of the engine 11 is smaller than the predetermined value C. The determination is made (step S14). The predetermined value C may be set to C=20 g/s in the case of an engine with a displacement of about 1.3 L, for example. The predetermined value C increases as the displacement increases.

Then, when the output request value of the engine 11 is smaller than the predetermined value C (step S14: YES), the control unit 37 performs the opening degree feedback control (step S17). This ensures that the valve element 35 is maintained in the fully open position. Therefore, when the intake air amount (mass flow rate) is small, even if there is a temporary change in the differential pressure across the intake switching valve 21, the valve body 35 can be prevented from rotating toward the valve closing side. Therefore, it is possible to prevent the cool air from being introduced into the intake passage 12.

On the other hand, when the output required value of the engine 11 is larger than the predetermined value C (step S14: NO), the control unit 37 uses the full open holding duty calculation map shown in FIG. The full-open holding duty (DUTY) applied to the motor 36 is calculated based on (step S15), and the motor 36 is controlled by the fixed duty control (step S16). That is, the motor 36 is duty-controlled by the full-open holding duty calculated in step S15.

Also in this embodiment, as described in the first embodiment, the control unit 37 acquires (estimates) the temperature of the motor 36 in addition to the intake air amount, and determines the full open holding duty based on the temperature of the motor 36. You may make it correct. In this case, the control unit 37 may store the full-open holding duty calculation map shown in FIG. 16 instead of the full-open holding duty calculation map shown in FIG. As a result, an appropriate full-open holding duty (DUTY) corresponding to the motor temperature is calculated, so that the valve element 35 can be reliably held at the fully open position even when the motor temperature is high, and when the motor temperature is low. Since the energization duty more than necessary is not applied to the motor 36, the power consumption can be further reduced.

<Third Embodiment>
Finally, although the third embodiment will be described, the same components as those in the second embodiment will be designated by the same reference numerals, description thereof will be omitted, and different points will be mainly described. The system configuration of this embodiment is the same as that of the second embodiment, but the content of the opening control of the intake switching valve 21 is different from that of the second embodiment. That is, unlike the second embodiment, when the output demand of the engine becomes large and the high duty state occurs, the control unit 37 gradually moves the fully open position of the valve body to the valve closing side. The opening correction is performed, and then the full-opening correction is canceled when the high duty state is lost. Specifically, the control unit 37 executes control based on the control flowcharts shown in FIGS. 17 and 18.

First, as shown in FIG. 17, the control unit 37 determines whether or not there is a request to introduce hot air, that is, a high temperature intake request. Specifically, the control unit 37 determines whether or not the high temperature intake flag HAflg is ON (step S30). When the high temperature intake flag HAflg is ON (step S30: YES), the control unit 37 determines whether the output request value for the engine 11 is smaller than the predetermined value A (for example, A=60 g/s). (Step S31).

When the output request value is smaller than the predetermined value A (step S31: YES), the control unit 37 fully opens the opening command value for the intake switching valve 21 (step S32), and the fully open flag is ON. It is determined whether or not (step S33). The fully open flag is OFF when the ignition switch is ON.

On the other hand, when the high temperature intake flag HAflg is OFF (step S30: NO), the controller 37 fully closes the opening command value for the intake switching valve 21 as shown in FIG. 18 (step S45). The full open flag is turned off (step S46). As a result, the valve body 35 is arranged at the fully closed position shown in FIG. 5, the hot air from the hot air passage portion 33 (hot air introduction passage 20) is blocked, and the cool air from the cool air passage portion 32 (intake inlet 22) is cooled by the air cleaner. It is introduced into the intake passage 12 after 14.

Also, when the output request value is larger than the predetermined value A (step S31: NO), the controller 37 executes the processes of steps S45 and S46. As a result, when the required output value of the engine 11 becomes large and a large amount of intake air is required, the intake switching valve 21 is fully closed, so that the introduction of hot air is stopped and the cool air is introduced early. As a result, it is possible to secure the intake air amount according to the output demand, improve the oxygen concentration with the introduction of the cool air, and prevent the output from decreasing.

Then, when the full open flag is ON (step S33: YES), the control unit 37, as shown in FIG. 17, the full open holding duty is a predetermined value (for determining the high duty state). It is determined whether it is larger than the duty value) (step S34). Note that, as the predetermined value here, for example, 30% may be set. As a result, when the full open holding duty is greater than 30%, the following high duty state determination is performed.

That is, when the full-open holding duty is larger than the predetermined value (step S34: YES), the controller 37 starts counting up the high duty counter (step S35), and based on the map shown in FIG. , A predetermined time for determining the high duty state is acquired (step S36).

Here, the map shown in FIG. 19 is a determination time calculation map for calculating a predetermined time (judgment time) for each duty value (DUTY) for making a high duty state judgment. In this determination time calculation map, the determination value (predetermined time) is calculated to be short because the duty value becomes large, and it is adjusted to the optimum one by experiments or the like for each specification of the engine 11. For example, in the present embodiment, it is set to 800 ms at a duty of 30%, 400 ms at a duty of 50%, and 300 ms at a duty of 80%.

Then, the control unit 37 determines whether the high duty counter has exceeded the predetermined time acquired in step S36 (step S37). At this time, when the high duty counter exceeds the predetermined time acquired in step S36 (step S37: YES), the control unit 37 determines that the high duty state is set, and starts the full opening degree correction. (Step S38), the high duty counter is reset (step S39). Note that the high duty state basically occurs when the output demand of the engine 11 increases and the required intake air amount increases, and the differential pressure across the intake switching valve 21 increases.
On the other hand, when the high duty counter does not exceed the predetermined time acquired in step S36 (step S37: NO), the control unit 37 determines that the high duty state is not set, and performs the process of step S61.

In the high duty state, the motor 36 may be overloaded. Therefore, the control unit 37 starts the full opening degree correction for moving the fully open position of the valve body 35 to the valve closing side. Specifically, the opening command value is corrected by 1° toward the closing side with respect to the current command value. This correction is performed until the full-open holding duty becomes smaller than the predetermined value, so the fully open position of the valve element 35 is gradually moved to the valve closing side, and the valve element 35 is gradually rotated to the valve closing side. The full-open holding duty becomes smaller. Finally, since the energization duty to the motor 36 becomes the minimum duty or less, the load on the motor 36 is reduced.

After that, the control unit 37 determines whether or not the output request value of the engine 11 is smaller than the predetermined value B (for example, B=30 g/s) (step S40). Then, when the output required value is smaller than the predetermined value B (step S40: YES), the full opening degree is updated (step S41). That is, the opening corresponding to the current opening command value is set to the full opening. As a result, when the output demand is small, the full-open opening is updated to the closed side when the full-open opening position is changed to the valve closing side due to foreign matter clogging or deformation due to temperature change. , The energization duty to the motor 36 is not set to be large (surplus). Therefore, even in such a case, the load on the motor 36 is reduced. When the output request value is larger than the predetermined value B (step S40: NO), the high output flag is turned on (step S70) and the return counter is reset (step S71).

On the other hand, when the fully open flag is OFF (step S33: NO), the control unit 37 determines whether the valve body 35 of the intake switching valve 21 is arranged at the fully open position as shown in FIG. A full-open judgment for judging is performed (step S50). This full open determination is performed by the same process as in the second embodiment. Then, when the control unit 37 determines that it is fully opened (step S50: YES), the fully opened flag is turned on (step S51), the high duty counter is reset (step S52), and the high output flag is turned off. (Step S53). On the other hand, when the control unit 37 determines that it is not fully opened (step S50: NO), it turns off the fully opened flag (step S54).

Further, when the high duty state is not set, that is, when the full-open holding duty is smaller than a predetermined value set in advance, or when the high duty counter does not exceed the predetermined time acquired in step S36, the control unit 37 As shown in FIG. 17, the following processing is performed. When the full-open holding duty is smaller than the predetermined value set in advance (step S34: NO), the controller 37 resets the high duty counter (step S60), and the output request value of the engine 11 is set to the predetermined value B (for example, B). , B=30 g/s) is determined (step S61). When the output request value is smaller than the predetermined value B (step S61: YES), the control unit 37 determines whether the high output flag is ON (step S62). At this time, when the high output flag is ON (step S62: YES), the return counter is counted up (step S63).

Then, the control unit 37 determines whether or not a predetermined time (for example, 1 second) has elapsed after the output counter value of the engine 11 has decreased by the return counter (step S64). Such a predetermined time (delay time) is provided to secure a time until the differential pressure across the intake switching valve 21 stabilizes after the output required value decreases, and after the differential pressure across the intake valve stabilizes, This is because the processing for canceling the full opening degree correction is performed.

When the predetermined time has elapsed (step S64: YES), the control unit 37 determines whether or not the current opening command value is smaller than the full opening (step S65). At this time, when the current opening degree command value is smaller than the full opening degree (step S65: YES), the control section 37 cancels the full opening degree correction (step S66). Specifically, in order to return the fully opened opening amount to its original value, the opening amount instruction value is corrected toward the opening side by 1° with respect to the current instruction value. This correction is performed until the opening command value reaches the full opening, and when the opening command value reaches the full opening (step S65: NO), the controller 37 turns off the high output flag (step S67). ).
When the high duty counter does not exceed the predetermined time acquired in step S36 (step S37: NO), the processes of steps S61 to S67 are performed.

As a result, when the output demand is reduced and the high duty state is not achieved, the fully open position of the valve element 35 gradually returns to the position before the full opening degree correction. Therefore, the valve body 35 rotates toward the valve opening side and returns to the normal fully open position (the position where the cool air passage portion 32 is fully closed), so that the hot air should be sufficiently introduced into the intake passage 12. You can

By executing the control based on the above control flowchart, for example, the control represented by the control time chart as shown in FIG. 20 is executed. That is, as shown in FIG. 20, when the required output value of the engine 11 exceeds the predetermined value B and becomes large at time T10 while the high temperature intake flag HAflg is turned on, the differential pressure in the intake switching valve 21 increases. Since it becomes larger, the full open holding duty becomes larger. Then, when the high duty state is reached at time T11, the full opening degree correction is executed. As a result, the opening degree command value is gradually reduced. Therefore, the valve body 35 rotates toward the valve closing side and the actual opening degree becomes smaller, so that the full open holding duty also becomes smaller. After that, when the high duty state disappears at time T12, the opening degree of the valve body 35 is maintained at the full open holding duty at that time.

Then, after the output required value of the engine 11 becomes smaller than the predetermined value B at time T13, the full-opening degree correction is canceled at time T14 when the return counter exceeds the predetermined time. As a result, the opening degree command value is gradually increased. Therefore, the valve body 35 rotates toward the valve opening side and the actual opening degree increases. After that, at time T15, the opening command value becomes the fully open opening, and the fully open position of the valve element 35 returns to the position before correction.

As described above, according to this embodiment, when the high temperature intake flag HAflg is ON and the required output value is smaller than the predetermined value A, the control unit 37 once opens the intake switching valve 21 until it is fully opened, and thereafter, When the high duty state is detected, the full opening degree correction is executed. Therefore, in the medium load region in which the required output value is larger than the predetermined value B and smaller than the predetermined value A, when the high duty state is reached, the opening degree command value gradually decreases, so that the valve body 35 turns to the valve closing side. The cool air passage portion 32 is also opened by the movement, and cool air is introduced into the intake passage 12 from the cool air passage portion 32 in addition to the hot air. Then, the energization duty to the motor 36 finally becomes equal to or less than the minimum duty. As a result, in the medium load region, it is possible to secure the required intake air amount while introducing the maximum amount of hot air while further reducing the load by reducing the energization duty to the motor 36.

When the output request value becomes smaller than the predetermined value B due to not being in the high duty state, the control unit 37 cancels the full opening degree correction and gradually moves the full opening position of the valve element 35 to the valve opening side. Therefore, the valve element 35 rotates toward the valve opening side and returns to the original fully opened position, so that the hot air can be sufficiently introduced into the intake passage 12.

Further, in the high load region in which the high temperature intake flag HAflg is ON and the required output value is larger than the predetermined value A, the control unit 37 fully closes the intake switching valve 21. As a result, cool air is introduced into the intake passage 12 from the cool air passage portion 32, so that it is possible to secure an amount of intake air according to the output demand and to improve the oxygen concentration with the introduction of cool air. Output reduction can be prevented.

It should be noted that the above-described embodiment is merely an example and does not limit the present invention, and it is needless to say that various improvements and modifications can be made without departing from the scope of the invention. For example, in the above embodiment, the energization duty to the motor 36 is calculated based on the intake air amount (mass flow rate), but the energization duty may be calculated based on the differential pressure across the intake switching valve 21. .. In this case, pressure sensors may be respectively provided on the upstream side and the downstream side of the intake switching valve 21 (valve element 35) to detect the differential pressure across the intake and outlet.

1 engine system 11 engine 12 intake passage 13 exhaust passage 14 air cleaner 18 intake temperature control device 19 shroud 20 hot air introduction passage 21 intake switching valve 22 intake inlet 31 intake passage portion 32 cool air passage portion 33 hot air passage portion 34 shaft 35 valve body 36 motor 37 Control unit

Claims (5)

A low temperature air passage portion for introducing low temperature air into an intake passage connected to an engine, a high temperature air passage portion for introducing high temperature air into the intake passage, and opening and closing the low temperature air passage portion and the high temperature air passage portion. In the intake switching valve, a valve body, a motor that rotationally drives the valve body, and a control unit that controls the opening of the valve body by duty-controlling the motor,
The control unit, when the introduction of high temperature air is requested, the torque required to arrange and hold the valve body at the fully open position where the low temperature air passage section is closed by the valve body and the high temperature air passage section is opened. A full-open holding duty, which is an energizing duty that causes the motor to generate a full-open holding duty, is set to a minimum duty necessary for holding the full-open position calculated based on an intake air amount taken into the engine valve. In the intake switching valve according to claim 1,
The intake switching valve, wherein the control unit sets the full-open holding duty to a predetermined duty smaller than the minimum duty when the required output value of the engine becomes larger than a predetermined first predetermined value. In the intake switching valve according to claim 1,
When the fully opened holding duty is a high duty state in which the fully opened holding duty is equal to or greater than a predetermined value and continues for a predetermined time, the controller performs a full opening degree correction to gradually move the fully opened position of the valve body to a valve closing side. Intake switching valve. The intake switching valve according to claim 3,
The control unit cancels the full-opening degree correction when the high duty state is lost and the required output value of the engine becomes smaller than the first predetermined value while the full-opening degree correction is being performed. An intake switching valve, characterized in that the fully open position of the valve element is gradually moved to the valve opening side. In the intake switching valve according to claim 1 or 2,
The intake switching valve, wherein the control unit corrects the full-open holding duty based on the temperature of the motor.

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