JPH0388914A - Electronic control system for rotary valve in engine suction line - Google Patents

Abstract

PURPOSE:To have rotational phase control with good followup performance even while the engine is in acceleration or deceleration by controlling the rotational phase of a rotary valve by a motor wherein the information on the basis of the angular acceleration of engine is taken into account. CONSTITUTION:A rotary valve 2 installed on the way of a suction pipe is driven by a motor 19. An electronic control device 23 compares the rotation angle of the motor 19 with the rotation angle of an engine 3 determined from the angular acceleration of the engine 3 sensed at real time by an acceleration sensor 22, and the rotational phase difference between the two is calculated. Comparison of this rotational phase difference is made with the target phase which is the difference of the rotational phase of the rotary valve 2 from the rotational phase of engine 3 decided in advance according to the revolving speed of the engine 3, and the motor 19 is controlled so that the difference between two nullifies. This enable achievement of the phase control having a good response together with synchronous control without generating steady deviation even though the engine 3 is in acceleration or deceleration.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an electronic control method for a rotary valve in an engine intake system, and is particularly applicable to a case where a motor performs synchronization control and phase control of a rotary valve with respect to engine rotation. It is very useful.

<Prior art> As shown in Fig. 9, the intake system of an automobile engine has
Some have a rotary valve 2 interposed in the middle of the intake pipe 1. The rotary valve 2 is controlled so that its rotation is synchronized with the rotation of the engine 3, and its phase is appropriately controlled to control the timing of intake of air into the engine 3. In other words, while the opening/closing timing of the intake valve 4 of the engine 3 and the opening/closing timing of the exhaust valve 5 are fixedly selected based on the vertical dead center in each intake/exhaust mode, in order to improve fuel efficiency, the engine There is a desire to stop the intake of air into the combustion chamber 7 relatively early in the low speed range of No. 3, and to stop it relatively early in the high speed range. The intake system having the rotary valve 2 described above has met this demand.

As described above, the reason why it is possible to improve fuel efficiency by making the timing of air intake variable between the low speed range and the high speed range of the engine 3 is as follows. That is, in the intake stroke, when the intake valve 4 is in the open state, the piston 6
By descending, air is sucked into the combustion chamber 7. At this time, since the descending speed of the piston 6 is slow in the low rotation range of the engine 3, air proportional to the amount of descending of the piston 6 is drawn into and filled into the combustion chamber 7. Even if the combustion chamber 7 is closed, the combustion chamber 7 can be moved to the compression process with substantially the maximum amount of air being filled in the combustion chamber 7. On the other hand, in the high rotation range of the engine 3, the descending speed of the piston 6 is fast, so even if the piston 6 descends, the inside of the combustion chamber 7 only becomes negative pressure, and the air cannot follow the descent of the piston 6. As a result of causing a time delay in the inflow into the combustion chamber 7, if the intake fp4 is closed at the bottom dead center of the piston 6, the combustion chamber 7
The pressure inside is lower than atmospheric pressure. That is, the amount of air filled in the combustion chamber 7 is smaller than in the low rotation range. Therefore, in case B, it is more desirable to delay the timing of stopping air intake until the inside of the combustion chamber 7 reaches atmospheric pressure, and then move to the compression process with a sufficiently large amount of air charged. .

In this way, the intake valve 4 is closed at a later timing than when a normal intake system without the rotary valve 2 is used, so that sufficient air is filled into the combustion chamber 7 even in the 11 rotation range of the engine 3. At the same time, in the low speed range, the timing of closing the rotary valve 2 is set relatively early, and the opening/closing timing of the intake valve 4 is kept fixed, so that the timing coincides with the timing at which the rotary valve 2 closes. Inhalation timing is variable.

Therefore, in the intake system shown in FIG. 9, the rotation of the rotary valve 2 is synchronized with 30 rotations of the engine, and
The system is designed to control the phase to correspond to the rotational speed of the motor, but conventionally, such synchronization and phase control was performed using a mechanical mechanism using a phase control device such as a cam and a differential gear. .

In Fig. 9, 8 is an air cleaner, 9 is an air flow sensor, 10 is an atmospheric temperature sensor, 11 is an exhaust gas pipe, 12 is a spark plug, 13 is a distributor, 14 is an ignition coil, 15 is a power transistor, and 16 is a crankshaft. 17 is a crank angle sensor, and 18 is an electronic control device.

<Problems to be Solved by the Invention> The above-described mechanical synchronization and phase control mechanism of the rotary valve 2 generally has a drawback that it has a large number of components and a complicated structure.

As a means of eliminating this drawback, a method can be considered in which the rotary valve 2 is directly rotationally driven by a motor and the rotation of the motor is electronically controlled. Therefore, in developing an electronic control system for the rotary valve 2, the inventor of the present application compared signals representing the rotation speed and phase of the engine 3 with signals representing the rotation speed and phase of the motor, and We have come up with a method of controlling the rotation of the motor so that the phase of the rotary valve 2 becomes a predetermined phase while maintaining synchronization with the rotary valve 3.

However, in the case of an electronic control method in which synchronous control and phase control of the rotary valve 2 are performed by controlling an electric motor,
If you try to control only the information on the rotation speed and phase of the engine 3 and the information on the rotation speed and phase of the motor, the engine 3
It was found that a steady deviation from the target phase occurs during acceleration and deceleration.

That is, a shemireshi experiment was conducted in which the rotation speed of the engine 3 was changed while the target phase of the rotary valve 2 was changed while comparing information on the rotation speed and phase of the engine 3 with information on the rotation speed and phase of the motor. 10th
The results shown in (a) and 10(b) were obtained.

Fig. 10 (&) is a characteristic diagram of motor rotation speed N, (actual S) with respect to engine rotation speed N, (point 1ll), and (10th opening) is the actual control for the target phase P1 (thick line) of rotary valve 2. It is a characteristic diagram of the actual phase p, (thin line) which is the result of the calculation. As shown in FIG. 10(a), the engine 3
The engine accelerates slightly from the initial idling state at the 0 point, continues to rotate at a constant speed for a while from the 0 point, accelerates for a while from the 0 point, and returns to the constant speed rotation state again at the 0 point. On the other hand, the motor rotation speed N2 is maintained at a substantially good speed even though there is a slight follow-up delay when the engine 3 accelerates.
is following. On the other hand, as shown in Figure 10 (bl),
Target phase P is initially set to zero, and P1 is set at point [F].
= +40° and from P = +40° at point [F] to P−-
The angle is changed to 40°. This target phase P is instructed by the CPU, and has nothing to do with the target phase that should be supplied when the vehicle is actually running, but is based on the most severe conditions imaginable when the vehicle is running, just for the purpose of checking controllability. and changing it. As is clear from FIG. 10(b), the motor cannot follow the increase in engine speed N2 during the period corresponding to the acceleration from 0 to 0, and the actual phase P2 of the rotary valve 2 is 50. ”It is delayed by some extent. Also, [F] point,
When the target phase P is changed at point [F], the actual phase P2 will have a slight follow-up delay, but the target phase P1 will be changed in a relatively short time.
It has converged on However, at the time corresponding to the steady acceleration from 0 point to 0 point, the motor can barely rotate synchronously with the engine 3, and the actual phase P is 50. A steady-state deviation C occurs, which is a delay of about .

In view of the above-mentioned points, the present invention provides a phase control system that provides synchronous control and good responsiveness without causing steady-state deviation even during engine acceleration/deceleration when a rotary valve is electronically controlled by a motor. The purpose of the present invention is to provide an electronic control method for rotary valves in an engine intake system that can realize control.

Means for Solving the Problems> The structure of the present invention that achieves the above object is to provide a rotary valve which is interposed in the middle of the intake pipe and is rotated by a motor, and whose rotational speed is equal to the rotational speed of the engine. The rotary valve in the engine intake system is designed to synchronize with the engine speed and control its rotational phase to have a predetermined phase difference with respect to the engine rotational phase, thereby adjusting the timing of air intake into the engine. In the electronic control method, the rotation angle of the engine, which is determined based on the angular acceleration of the engine detected in real time by an acceleration detector, is compared with the rotation angle of the motor that drives the rotary valve, and the rotation phase difference between the two is determined. The target phase, which is a rotational phase difference between the rotational phase of the engine and the rotational phase of the rotary valve, which is predetermined according to the engine rotational speed, is compared with the rotational phase difference, and the motor is adjusted so that the difference between the two becomes zero. I would like to specifically mention the fact that it is controlled.

<Operation> According to the present invention having the above configuration, the rotational phase of the rotary valve is controlled by the motor in consideration of information based on the angular acceleration of the engine.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Note that parts that are the same as those in the prior art are given the same numbers and redundant explanations will be omitted.

FIG. 1 is an explanatory diagram conceptually showing an entire apparatus for realizing an embodiment of the present invention. As shown in the figure, the rotary valve 2 is rotatably driven by a motor 19. The rotation angle of the motor 19 is determined by a rotation angle sensor 20, which will be described in detail later, every 2° and 90° rotation of a disc 23 that is fixed to the shaft of the motor 19 and rotates integrally with the motor 19.
21.

Acceleration detection @22 is the camshaft 1 of the distributor 13
Although the detailed structure will be described later, the angular acceleration of the engine 3 is detected through the rotation of the camshaft 16 that rotates in synchronization with the crankshaft.

The electronic control device 23 is supplied with various information as well as the output signals of the rotation angle sensors 20 and 21 and acceleration detection @22.
, 21 and the acceleration detection M22 to control the rotation speed of the motor 190.
fbII is controlled so that the rotations of the engine 3 and the engine 3 are synchronized and the phase difference is maintained at a predetermined value.

FIG. 2 is a perspective view showing a mechanism for detecting the rotational phase of the motor 19. As shown in the figure, the disc 24 fixed to the shaft of the motor 19 has an angle of 2° in the circumferential direction of its outer periphery.
A slit 24m is formed at each position, and a slit 24b is formed at every 90° in the center direction. The rotation angle sensors 20 and 21 include light emitting sections 20m and 21m and a light receiving section 20b, which are arranged to face each other on both sides of the disk 24, respectively.

21b, and the light emitted from the light emitting parts 20m and 21m is passed through the slits 24a and 24b to the light receiving part 20b.
, 21b, the light receiving sections 20b, 21b send out pulse signals that rise each time the disc 24, ie, the motor 19, rotates at V and 9V, respectively.

FIG. 3(a) is a vertical sectional view showing an extracted part of the acceleration detector 22, and FIG. 3(b) is a right side view of the main part thereof. As shown in both figures, a ring 26 is fitted onto a shaft 25 connected to a camshaft 16 that is synchronized with engine rotation so as to be movable in the axial direction. Arm plate 27 formed from a flexible member
; One base end is fixed to the ring 26 and the other base end is fixed to the convex portion 25m of the shaft 25, and a bimorph element 28 extends in the radial direction of the shaft 25 at one and the other tip end. The proximal end of is fixed. Further, a spring 29 is fitted between the ring 26 and the convex portion 25a. Furthermore, a weight 30 is fixed to the tip of the bimorph element 28. At this time, as particularly shown in FIG. 3(b), four sets of arm plates 27 are arranged at equal intervals around the shaft 25, and a weight 30 is fixed to each arm plate 27 as described above. A bimorph element 2B is fixed.

Thus, the ring 26 moves on the shaft 25 against the spring force of the spring 29 due to the centrifugal force acting on the weight 30 as the shaft 25 rotates, and stops when the centrifugal force and the spring force are balanced. This state is maintained as long as the rotational speed of the shaft 25 does not change. In this state, when the rotational speed of the shaft 25 changes as the engine rotational speed changes, that is, when the engine 3 accelerates or decelerates, the ring 26 moves in the left direction (during acceleration) in FIG. 3(a). ) or move to the right (when decelerating). At this time, since the weight 3o has a large inertia, it cannot follow the movement of the ring 26, and as a result, the bimorph element 28 is bent in a direction parallel to the axis 25. That is, during acceleration, it deflects to the right in FIG. 3 (al), and during deceleration, it deflects to the left. The amount of this deflection is proportional to the magnitude of the angular acceleration at this time, and is proportional to the output voltage of the bimorph element 28.

Therefore, the output voltage of the bimorph element 28 is measured by the voltmeter 3.
1, the angular acceleration of the engine 3 can be detected.

In Fig. 3(a), 32 is a case, 33 is a bearing, and 34 is a case.
is a cover and 35 is an oil seal.

FIG. 4 shows 1111! according to this embodiment! FIG. 2 is a block diagram showing the II system. As shown in the figure, the angular acceleration, which is the rate of change in engine speed, changes as the accelerator 40 is moved. By integrating this angular acceleration twice (see block 41), the rotational phase of the engine 3 (
The rotational phase θ of the crank is determined, and this rotational phase θ1 is compared with the current rotational phase θ of the motor 19 to determine the amount of deviation between the two (θ, -0,). Then, this amount of deviation (
θ. −〇, ) and the target phase value PHT to find the deviation DTH between the two. At this time, the target phase value PHT is supplied from a map prepared in advance in consideration of the rotation speed and load of the engine 3.

Furthermore, PD opening control is performed based on the deviation DTH (see blocks 42 and 43). Since a DC motor is used as the motor 19 in this embodiment, the control amount obtained as a result is given as the duty of the motor 19. In this embodiment, the motor torque is controlled by controlling the duty of the motor 19. As a result, the angular acceleration of the motor 19 is determined by dividing the amount of change in the motor torque that changes due to the change in duty by the moment of inertia IM of the entire rotating system related to the motor 19 (see block 44). . Find the angular velocity ω based on this angular acceleration F (see block 45)
, based on this angular velocity ω, the rotational phase θ. seek.

FIG. 5 is a timing chart showing control timing in this embodiment. In the same figure, ■ indicates the rotation of engine 3 at 90"
The engine 9 detected by the crank angle sensor 17 every time
0° signal, ■ is sensor 2 every 90 @ rotation of motor 19
Motor 90° signal detected by 1, ■ is motor 19
The motor 2 is detected by a sensor 20 every 2 degrees of rotation of the motor 2.
° signal, ■ is the counter CM built in the electronic control unit 23
The motor 2° signal counted by i, the motor 2° signal counted by the counter CM2 built in the electronic control unit 23, and the target phase value PHT of the motor 90° signal.

2 is a read signal sent every 10 m5ec from the 10m5ec timer.

Note that since the engine 3 according to this embodiment has a 4-cycle cycle, the rotation speed of the motor 19 is 1/4 of the rotation speed of the engine 3.
However, the motor 90'' and 2° signals referred to here are those converted to equivalent crank angles.

As shown in FIG. 5, counter CM1. CM.

is to alternately count the number of motor 2° signals (■) from the rise of the motor 90° signal (■) to the rise of the engine 90° signal (■). These counters CM1. Subtract the number of motor 2° signals (■) corresponding to 90° from the count value of CM2 (thereby, the rotational phase shift between the motor 19 and the engine 3 is detected.

The difference between the motor 90° signal (■) and the target phase IIPHT becomes the deviation DTH, and the immediately preceding deviation DTH is read with the read signal (■). Based on this deviation DTH, the motor duty is calculated during period T, and the calculation result is applied to the engine 90 immediately after.
° Signal ■ is supplied to the remoter 19. This timing is indicated by the symbol I in FIG.

FIG. 6 is a flowchart showing the processing performed each time the engine 90° signal (2) rises. As shown in the figure, the processing in this case is as follows.

1) The angular acceleration of the engine 3 is detected by the acceleration detector 22.
(see block 50).

2) Determine whether a phase shift has occurred in the rotational phase of the motor 19 with respect to the target phase value PHT, and if a phase shift has occurred, set the CF (control flag)
Otherwise, set CF=O (see block 51).

3) When a phase shift occurs, 1 is given to the motor duty obtained by adding the correction value β to the motor duty corresponding to the angular acceleration ω4 (see block 52).

4) When no phase shift occurs, the motor data 1-Kl corresponding to the angular acceleration 2 read from the map is given (see block 53).

5) Determine which counters CM, CM2 are to be stopped (see block 54).

6) Stop either counter CM or CM2 (
(see blocks 55, 56).

7) When the counter CM is stopped, R8 Tomi C
M, (count value of counter CMl).

Set counter CM, = 0 (clear the value of counter CM,) and CFC = 2 C, which stops at the next engine 9v signal (CM, ) (see block 57).
.

8) When counter C's is stopped, R2 is 0.
Let M10~=0 and CFC=1 (see block 58).

FIG. 7 is a flowchart showing the processing performed every time the motor 90° signal (2) rises. As shown in the figure, the processing in this case is as follows.

1) Determine which counter CM, CMII is operating (see block 59).

2) If counter CM is operating, counter CM2 is operated, and if counter CMa is operating, counter CM is operated (block 60.61).
reference).

8(a) and 8(b) are 1011141110
3 is a flowchart showing interrupt processing by a timer.

As shown in the figure, the processing in this case is as follows.

1) 10m5e at the rising edge of 10ma/C pulse.

The timer is reset and the following processing is started. That is, the following processing is performed every time the timer measures a period of 10m5ec (see block 62).

2) Read the target phase value PHT and engine speed N9 (see block 63).

3) Save the value from the previous calculation. That is, DTHB DT
Let H (@difference), DDTHB, and DDTH (amount of change in deviation) (see block 64).

0 Calculate the deviation DTH from the target phase value PTH and the amount of change DDTH in the deviation DTH (see block 6S). That is, DTH-PHT+90-R,, DDTH-DTH-D
THB 0 However, R = the count value of counter CM.

5) Determine whether IDTHI≧2 or 1DDTH1≧2 (see block 66). V is the limit of the resolution of the deviation DTH.

1 in the adjacent dead zone to determine IDDTH+≧2
This is to detect a case where the change is more than that.

6) If the determination result in 5) is Yes, set a motor torque change flag (see block 67). That is, it is set as CF depth 1.

? ) Determine IDTHI<45 (see block 68).

8) If the determination result in 7) is No, that is, if the deviation DTH is extremely large, the correction value β has a positive or negative sign equal to the angular acceleration α0.8 that outputs the maximum torque of the probe motor 19 (see block 69). ). That is, β-5GN(α.)×
Set it as α3.11.

9) If the determination result in 7) is Y@s, calculate the motor angular acceleration α, (snow, XDHT+, XDDTH) for changing the motor torque (see block 70).

10) Determine the maximum capacity of the motor 19 (refer to block 71), if Yes, perform the process of block 69 in the same manner as in 8) above,
In the case of No, set the correction value β 瓢α (block 72
reference).

11) If the determination result in 5) is No, lower the motor torque change flag (see block 73). That is, C.F.
= O.

<Effects of the Invention> As specifically explained above with the embodiments, according to the present invention, the angular acceleration of the engine is detected in real time,
The motor that rotates the rotary valve is controlled by taking this angular acceleration into account, and the rotational phase of the rotary valve is adjusted to the rotational phase of the engine, so even when the engine is accelerating or decelerating, the engine and rotary valve are Not only synchronous control but also control of the rotational phase of both can be performed with good followability.

[Brief explanation of drawings]

1rIA is an explanatory diagram conceptually showing the entire device for realizing an actual IM example of the present invention, FIG. 2 is a perspective view showing a mechanism for detecting the rotational phase of the rotary valve, and FIG. 3(a) is 3(b) is a right side view of the essential parts, FIG. 4 is a block diagram showing the control system according to the embodiment of the present invention, and FIG. 5 is a longitudinal sectional view showing an extracted acceleration detector. A timing diagram showing the control timing, FIG. 6 is a flowchart showing the process according to the embodiment performed every time the engine rotates 90 degrees, and FIG. 7 is a flow chart showing the process according to the embodiment performed every time the motor rotates 90 degrees. Flowcharts showing such processing, FIG. 8(a) and FIG. Figure 10 (a) and Figure 10 (
b) is a graph showing its control characteristics. In the drawings, 1 is an intake pipe, 2 is a rotary valve, 3 is an engine, 19 is a motor, and 22 is an acceleration detector.

Claims (1)

[Scope of Claims] A rotary valve, which is interposed in the middle of the intake pipe and driven by a motor, has a rotational speed that is synchronized with the engine rotational speed, and whose rotational phase is synchronized with the engine rotational phase. In the electronic control system of the rotary valve in the engine intake system, which controls the timing of air intake into the engine by controlling it to have a predetermined phase difference between the The engine rotation angle determined based on the angular acceleration of the rotary valve is compared with the rotation angle of the motor that drives the rotary valve to determine the rotational phase difference between the two. The intake air of the engine is characterized in that the target phase, which is a rotational phase difference between the phase and the rotational phase of a rotary valve, is compared with the rotational phase difference, and the motor is controlled so that the difference between the two becomes zero. Electronic control method for rotary valves in systems.