WO2016088330A1

WO2016088330A1 - Control device

Info

Publication number: WO2016088330A1
Application number: PCT/JP2015/005827
Authority: WO
Inventors: 真一杉浦
Original assignee: 株式会社デンソー
Priority date: 2014-12-03
Filing date: 2015-11-24
Publication date: 2016-06-09
Also published as: DE112015005496T5; JP6304003B2; DE112015005496B4; JP2016108976A

Abstract

This control device is provided with: a rotational angle detection unit (211) for detecting the rotational angle of a cam (17); a power supply unit (212) for supplying power to a motor (15) in order to perform a switching operation in which the area of the cam outer peripheral surface (17a) in contact with a control member (12) is switched between a first stationary part and a second stationary part that do not allow the control member to be displaced even if the cam rotates; a work-amount calculation unit (213) for calculating the work amount carried out by the motor in order to perform the switching operation; and a gain calculation unit (214) which calculates the gain on the basis of the work amount calculated by the work amount calculation unit. The power supply unit uses the gain calculated by the gain calculation unit to perform feedback control in which the power supplied to the motor is adjusted such that the rotational angle detected by the rotational angle detection unit becomes a target value.

Description

Control device

Cross-reference of related applications

This application is based on Japanese Patent Application No. 2014-244891 filed on December 3, 2014, the contents of which are incorporated herein by reference.

The present disclosure relates to a control device that controls a motor, rotates a cam by driving the motor, and displaces a control member that comes into contact with the outer peripheral surface of the cam to switch the operating state of the internal combustion engine.

2. Description of the Related Art An internal combustion engine mounted on a vehicle is known that switches intake and exhaust characteristics according to the operating state of the internal combustion engine. Specifically, the maximum lift amount of the intake valve and exhaust valve provided in the cylinder of the internal combustion engine is switched so as to be suitable for the operating state of the internal combustion engine at that time.

The following Patent Document 1 describes a control device that displaces a control member using a motor and a cam and performs the switching by the action of the control member. The cam that rotates as the motor is driven is configured to bring the control member into contact with the outer peripheral surface thereof. The control member abuts the outer peripheral surface of the cam at one end, and the other end extends to the internal combustion engine.

The cam is formed such that the distance from the center of rotation to the outer peripheral surface differs depending on the portion of the outer peripheral surface. For this reason, when the contact part of a control member and a cam changes with rotation of a cam, a control member is comprised so that it may displace.

A plurality of stationary portions (step portions) are formed on the outer peripheral surface of the cam. This stationary part is formed so that the inclination of the displacement amount of the control member accompanying the rotation of the cam is different from other parts. The control device disclosed in Patent Document 1 is configured to switch the position of the control member by setting the control member in contact with any one of the plurality of stationary portions.

The control member has an action suitable for the operating state of the internal combustion engine at that time by switching the position as appropriate. Thereby, the output improvement of an internal combustion engine, a fuel consumption reduction, etc. can be aimed at.

JP 2014-1119087 A

The characteristics of the internal combustion engine have individual differences even if they are of the same type, and the force that the control member receives from the internal combustion engine also differs for each individual internal combustion engine. For this reason, the amount of work performed by the motor before the control member is displaced to the target position while resisting the force also varies from individual to individual. Therefore, there is a problem that it is difficult to quickly displace the control member to the target position and switch the operating state of the internal combustion engine.

An object of the present disclosure is to provide a control device that switches the operating state of an internal combustion engine by quickly and accurately displacing a control member to a target position.

In one aspect of the present disclosure, a control device that controls the motor, rotates the cam by driving the motor, and displaces the control member that contacts the outer peripheral surface of the cam to switch the operating state of the internal combustion engine. Switching operation for switching the rotation angle detection unit that detects the rotation angle and the portion of the outer peripheral surface of the cam that the control member contacts between the first stationary unit and the second stationary unit that do not displace the control member even when the cam rotates. A power supply unit that supplies power to the motor to perform the operation, a work amount calculation unit that calculates the work amount that the motor has performed to perform the switching operation, and a gain that is calculated based on the work amount calculated by the work amount calculation unit A gain calculating unit. The power supply unit performs feedback control using the gain calculated by the gain calculation unit to adjust the power supplied to the motor so that the rotation angle detected by the rotation angle detection unit becomes a target value.

The work amount calculating unit calculates the amount of work performed by the motor in the switching operation between the first stationary unit and the second stationary unit. The gain calculation unit calculates a gain based on the work amount, and the power supply unit performs feedback control using the gain so that the rotation angle of the cam matches the target value. Therefore, even when the work amount of the motor in the switching operation varies due to variations in the characteristics of the internal combustion engine, the control shaft can be quickly and accurately displaced to the target position by using a gain corresponding thereto. It becomes possible to switch the operating state of the internal combustion engine.

According to this, it is possible to provide a control device that switches the operating state of the internal combustion engine by quickly and accurately displacing the control member to a target position.

The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings.
1 is a schematic configuration diagram of a valve control system to which a control device according to an embodiment is applied. It is a figure which shows schematic structure of a cam and a control shaft. It is a control block diagram for demonstrating a control apparatus. It is a figure which shows the relationship between an axial force and an engine speed. It is a flowchart which shows the control by a control apparatus. It is a figure which shows the relationship between the rotation angle of a cam, and the electric current supplied to the motor. It is a figure which shows the relationship between a gain ratio and the work of a motor. It is a figure which shows the relationship between a gain ratio and an engine speed.

Embodiments will be described with reference to the drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

First, an overview of the control device 21 according to the embodiment and the valve control system 11 to which the control device 21 is applied will be described with reference to FIGS. 1 to 3. The valve control system 11 is a system that controls an intake valve and an exhaust valve of the internal combustion engine 100 mounted on the vehicle. The valve control system 11 includes a control shaft 12 (control member), an actuator unit 13, and a valve opening / closing characteristic changing mechanism 14.

As shown in FIG. 1, the control shaft 12 is a rod-like member that is displaced by sliding in the axial direction. One end 12a of the control shaft 12 is provided on the actuator unit 13 side, and the other end 12b is provided on the valve opening / closing characteristic changing mechanism 14 side.

The actuator unit 13 is a mechanism that applies an axial force to the control shaft 12 to displace the control shaft 12. The actuator unit 13 includes a motor 15, a speed reducer 16, a cam 17, and a rotation angle sensor 19.

The motor 15 is a prime mover that is driven to rotate by receiving power and generates torque. The output shaft of the motor 15 is connected to the speed reducer 16. Torque generated by the motor 15 is transmitted to the cam 17 via the speed reducer 16.

As shown in FIG. 2, the cam 17 is configured to rotate around the rotation center RC when torque is transmitted from the speed reducer 16 as the motor 15 rotates. The outer peripheral surface 17a of the cam 17 is formed as a curved surface. The cams 17 are formed such that the distance from the rotation center RC to the outer peripheral surface 17a is different depending on the portion of the outer peripheral surface 17a.

1st stationary part LP, 2nd stationary part MP, and 3rd stationary part HP are formed in the outer peripheral surface 17a of the cam 17 at intervals. Among these, the 1st stationary part LP is a site | part with the shortest distance from the rotation center RC. The third stationary part HP is a part having the longest distance from the rotation center RC. That is, the distance from the rotation center RC is configured to increase in three stages from the first stationary part LP to the third stationary part HP through the second stationary part MP. In FIG. 2, for convenience of explanation, the first stationary part LP, the second stationary part MP, and the third stationary part HP are indicated by bold lines. One end 12 a of the control shaft 12 is in contact with the outer peripheral surface 17 a of the cam 17.

The rotation angle sensor 19 is a sensor that is arranged in the vicinity of the cam 17 and outputs a signal according to the rotation angle from the reference position of the cam 17. A signal output from the rotation angle sensor 19 is input to the control device 21 (see FIG. 1) via a signal line.

The valve opening / closing characteristic changing mechanism 14 is attached to the internal combustion engine 100. The valve opening / closing characteristic changing mechanism 14 is a mechanism for switching the intake and exhaust characteristics of the internal combustion engine 100 by changing the opening / closing characteristics of the intake valve and the exhaust valve. Specifically, the valve opening / closing characteristic changing mechanism 14 changes the maximum lift amount and operating angle of the intake valve and the exhaust valve of the internal combustion engine 100. The other end 12 b of the control shaft 12 is connected to the valve opening / closing characteristic changing mechanism 14.

The control device 21 controls the valve control system 11 as described above. The control device 21 is electrically connected to the motor 15 and the rotation angle sensor 19, and receives a signal to perform processing or supply power.

A part or all of the control device 21 is configured by an analog circuit or a digital processor including a memory. In any case, a functional control block is configured in the control device 21 in order to fulfill the function of outputting a control signal based on the received signal. FIG. 3 shows the control device 21 as such a functional control block diagram. It should be noted that the software module incorporated in the analog circuit or digital processor constituting the control device 21 does not necessarily have to be divided like the control block shown in FIG. That is, it may be configured to function as a plurality of control blocks, or may be further subdivided. As long as the control device 21 is configured to execute a processing flow described later, the actual configuration inside the control device 21 can be appropriately changed by those skilled in the art.

As illustrated in FIG. 3, the control device 21 includes a rotation angle detection unit 211, a power supply unit 212, a power amount calculation unit 213 (work amount calculation unit), and a gain calculation unit 214 as functional control blocks. And a storage unit 215.

The rotation angle detection unit 211 processes the signal received from the rotation angle sensor 19. The rotation angle detector 211 detects the rotation angle of the cam 17 by this processing.

The power supply unit 212 supplies driving power to the motor 15 of the actuator unit 13. Specifically, the power supply unit 212 supplies the electric power stored in a battery (not shown) to the motor 15 while adjusting the supply amount so that the rotation angle of the cam 17 matches the target value.

The power amount calculation unit 213 calculates the amount of power supplied from the power supply unit 212 to the motor 15. A method for calculating this electric energy will be described later.

The gain calculation unit 214 calculates a gain used for feedback control. The gain calculated here is used in PID control for making the rotation angle of the cam 17 coincide with the target value.

The storage unit 215 writes various data used for control processing in the control device 21 and enables reading of the data. Specifically, the gain calculated by the gain calculation unit 214 is written in the storage unit 215, and the gain can be read by the power supply unit 212.

In the following, for the sake of simplicity, the processing performed by each block such as the rotation angle detection unit 211 of the control device 21 will be described as being performed by the control device 21 as a whole.

When the control device 21 determines from the signal received from the rotation angle sensor 19 that there is a difference between the rotation angle of the cam 17 and the target value, the control device 21 supplies electric power to the motor 15 so that the rotation angle matches the target value. Start supplying. The motor 15 is rotationally driven according to the supplied electric energy, and the cam 17 is also rotated accordingly.

Of the outer peripheral surface 17 a of the cam 17, the part with which the one end 12 a of the control shaft 12 abuts changes as the cam 17 rotates. Furthermore, the distance from the rotation center RC of the cam 17 to the one end 12a changes as the contact portion between the outer peripheral surface 17a and the one end 12a changes. Thereby, the control shaft 12 is displaced so as to reciprocate in the axial direction.

Here, the rotation angle of the cam 17 and the displacement of the control shaft 12 are uniquely related. For this reason, the position of the control shaft 12 can be converged to the target position by performing feedback control in which the detected value of the rotation angle of the cam 17 by the rotation angle sensor 19 matches the target value.

Further, the first stationary part LP, the second stationary part MP, and the third stationary part HP of the outer peripheral surface 17a described above are formed so as not to displace the control shaft 12 when the cam 17 rotates. That is, the first stationary part LP, the second stationary part MP, and the third stationary part HP are all formed in an arc shape having a constant radius, and when the one end 12a of the control shaft 12 passes through them, it rotates. The distance from the center RC to the one end 12a is not changed. Therefore, only when the one end 12a is in contact with the first stationary part LP, the second stationary part MP, or the third stationary part HP, the control shaft 12 remains stationary without being displaced even when the cam 17 rotates. It becomes.

The internal combustion engine 100 receives different actions depending on the position of the control shaft 12. When one end 12a of the control shaft 12 is in contact with the first stationary portion LP of the outer peripheral surface 17a of the cam 17, the maximum lift amount of the intake valve and the exhaust valve of the internal combustion engine 100 is minimized. On the other hand, when the one end 12a of the control shaft 12 is in contact with the third stationary portion HP of the outer peripheral surface 17a of the cam 17, the maximum lift amount of the intake valve and the exhaust valve of the internal combustion engine 100 is maximized. When the one end 12a of the control shaft 12 is in contact with the second stationary part MP of the outer peripheral surface 17a of the cam 17, the maximum lift amount of the intake valve and the exhaust valve of the internal combustion engine 100 is the same as that of the first stationary part LP. It is larger than the case where it is in contact, and smaller than the case where it is in contact with the third stationary part HP. That is, the control device 21 switches the lift amount of the intake valve and the exhaust valve to 3 by switching the position where the control shaft 12 contacts to one of the first stationary part LP, the second stationary part MP, and the third stationary part HP. You can switch to the stage.

Next, the force applied to the control shaft 12 in the valve control system 11 configured as described above will be described with reference to FIG.

During operation of the internal combustion engine 100, the control shaft 12 is given a force resulting from vibration of the internal combustion engine 100 and movement of the intake valve and the exhaust valve. Specifically, axial force is applied to the control shaft 12 from the internal combustion engine 100 via the valve opening / closing characteristic changing mechanism 14. Hereinafter, this force is referred to as axial force. The axial force becomes a resistance force when the motor 15 rotates to displace the control shaft 12.

This axial force has a correlation with the rotational speed of the internal combustion engine 100. As shown in FIG. 4, the solid line AB indicating the reference characteristic of the internal combustion engine 100 shows a tendency that the axial force becomes large in the low rotation range and the high rotation range. For this reason, when the control shaft 12 is displaced, the force that the motor 15 needs to apply to the control shaft 12 via the cam 17 varies with the rotational speed of the internal combustion engine 100, and the low rotation range and the high rotation speed are changed. Especially in areas.

Incidentally, even if the internal combustion engine 100 to which the valve control system 11 is applied is of the same type, individual differences occur in its characteristics due to variations in its manufacturing process and use conditions. For this reason, the axial force that the control shaft 12 of the valve control system 11 receives from the internal combustion engine 100 also differs for each individual internal combustion engine 100.

Therefore, as shown in FIG. 4, in one individual, the axial force tends to be higher than the reference as indicated by a broken line AH, and in another individual, the axial force is lower than the reference as indicated by a broken line AL. Variations in individual characteristics, such as showing trends, occur. As described above, when the characteristics of the internal combustion engine 100 vary from one individual to another, the operation state of the internal combustion engine 100 can be switched by quickly and accurately displacing the control shaft 12 to a target position by feedback control. It becomes difficult.

Therefore, the control device 21 according to the present embodiment attempts to solve this problem by adjusting the gain used for this feedback control. Hereinafter, the control processing of the control device 21 will be described with reference to FIGS.

First, as shown in FIG. 5, the control device 21 moves from the second stationary part MP to the third stationary part MP while moving the one end 12a of the control shaft 12 from the first stationary part LP to the second stationary part MP in S1. During the movement to the stationary part HP and during the movement from the third stationary part HP to the first stationary part LP, the amount of work performed by the motor 15 is calculated.

Here, the work done by the motor 15 can be calculated from the current and voltage supplied to the motor 15. As shown in the upper part of FIG. 6, the value of the current supplied to the motor 15 during the driving of the motor 15 so that the detected value of the rotation angle of the cam 17 by the rotation angle sensor 19 matches the target value is The change shown in the lower part of FIG. 6 is shown. Among these, the area S shown in the lower part of FIG. 6 and the voltage supplied to the motor 15 are calculated in a calculation period, which is a period from when the detected value by the rotation angle sensor 19 starts to change to the target value. The amount of power that is the product is the amount of work performed by the motor 15.

Next, the control device 21 calculates a gain ratio based on the calculated work amount of the motor 15 in S2. The control device 21 stores the gain ratio-motor work amount map shown in FIG. 7 in the storage unit 215 (see FIG. 3). The control device 21 calculates the gain ratio based on the gain ratio-motor work amount map.

In this gain ratio-motor work amount map, the work amount of the motor 15 corresponding to the reference characteristic of the internal combustion engine 100 is set as a “reference value”. In the gain ratio-motor work amount map, the gain ratio corresponding to the “reference value” is “1”. The gain ratio is set to change proportionally as the work amount of the motor 15 deviates from the reference value due to variations in the characteristics of the internal combustion engine 100.

The control device 21 calculates the gain ratio by comparing the calculated work amount of the motor 15 with this gain ratio-motor work amount map. That is, the control device 21 calculates a ratio between an appropriate gain corresponding to the characteristics of the internal combustion engine 100 and a gain when the work amount of the motor 15 is the “reference value”. The control device 21 calculates gain ratios corresponding to the different rotational speeds of the internal combustion engine 100.

Next, the control device 21 stores the calculated gain ratio in S3. Specifically, the control device 21 writes the calculated gain ratio in the storage unit 215 (see FIG. 3) in association with the calculated gain ratio and the rotational speed of the internal combustion engine 100 when the gain ratio is calculated.

As described above, the gain ratio corresponding to the rotational speed of the internal combustion engine 100 is written into the storage unit 215, whereby a gain ratio-internal combustion engine rotational speed map as shown in FIG. The By dividing the rotational speed of the internal combustion engine 100 finely and calculating the gain ratio at each rotational speed, a continuous gain ratio value as shown in FIG. 8 can be obtained.

The control device 21 uses the gain ratio-gain ratio obtained from the internal combustion engine speed map when performing feedback control for matching the detected value of the rotation angle of the cam 17 by the rotation angle sensor 19 with the target value. That is, the control device 21 first calculates the gain ratio by comparing the rotational speed of the internal combustion engine 100 with this gain ratio-internal combustion engine speed map. Next, the control device 21 uses, for feedback control, a new gain obtained by multiplying the gain corresponding to the reference characteristic of the internal combustion engine 100 by the calculated gain ratio.

As described above, in the control device 21 according to the present embodiment, the first stationary part LP and the second stationary part MP, the second stationary part MP and the third stationary part HP, and the third stationary part. In the switching operation between the part HP and the first stationary part LP, the amount of work done by the motor 15 is calculated. A gain is calculated based on this electric energy, and feedback control is performed using the gain so that the rotation angle of the cam 17 coincides with the target value, so that control is performed according to the individual characteristics of the internal combustion engine 100. The operating state of the internal combustion engine 100 can be switched by quickly and accurately displacing the shaft 12 to a target position.

Further, the control device 21 calculates the amount of work performed by the motor 15 in the switching operation from the amount of electric power supplied to the motor 15. This is possible because the amount of power supplied to the motor 15 in the switching operation has a proportional correlation with the amount of work performed by the motor 15. Therefore, the control device 21 can easily and accurately calculate the amount of work performed by the motor 15.

Further, the control device 21 calculates gains corresponding to different rotational speeds of the internal combustion engine 100. As a result, even if the axial force applied to the control shaft 12 from the internal combustion engine 100 changes depending on the rotational speed of the internal combustion engine 100, feedback control can be performed using a gain that changes accordingly. Therefore, the operating state of the internal combustion engine 100 can be switched by quickly and accurately displacing the control shaft 12 to the target position according to the rotational speed of the internal combustion engine 100.

The embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. In other words, those specific modifications made by those skilled in the art as appropriate are included in the scope of the present disclosure. Each element included in each of the specific examples described above and their arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be appropriately changed.

Claims

The operating state of the internal combustion engine (100) is controlled by controlling the motor (15), rotating the cam (17) by driving the motor, and displacing the control member (12) contacting the outer peripheral surface (17a) of the cam. A control device (21) for switching between
A rotation angle detector (211) for detecting the rotation angle of the cam;
In order to perform a switching operation for switching a portion of the outer peripheral surface of the cam with which the control member abuts between a first stationary portion and a second stationary portion that does not displace the control member even when the cam rotates. A power supply unit (212) for supplying power;
A work amount calculation unit (213) for calculating a work amount performed by the motor to perform the switching operation;
A gain calculation unit (214) that calculates a gain based on the work amount calculated by the work amount calculation unit;
The power supply unit uses the gain calculated by the gain calculation unit to perform feedback control for adjusting power supplied to the motor so that the rotation angle detected by the rotation angle detection unit becomes a target value .
The control device according to claim 1, wherein the work amount calculation unit calculates the amount of power supplied to the motor by the power supply unit in order to perform the switching operation.
The control device according to claim 1, wherein the gain calculation unit calculates the gain corresponding to each of different rotational speeds of the internal combustion engine.