JP2003262110A - Control device for electromagnetic drive valve for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform sitting control of an electromagnetic drive valve by estimating the fluctuation of the neutral position of a valve during an engine operation. <P>SOLUTION: A neutral position (a neutral valve lift amount with which the spring force in a valve opening direction by an open side spring 43 is balanced with the spring force in a valve closing direction by a close side spring 29) of a valve 24 is estimated by using an equation of motion analyzing the moving states of movable parts of the valve 24 or the like during engine operation. Since data of the valve lift amount, velocity and acceleration are needed for the equation of motion, the valve lift amount is detected by a lift sensor 47, time differentiation of this valve lift amount is carried out to obtain the velocity, and time differentiation of the velocity is carried out to obtain the acceleration. In this case, since effects of noise or a quantization problem are eliminated if the acceleration is obtained by filtering the value of the differentiation of the velocity, variation characteristics of acceleration become a smooth curve and the estimation accuracy of the neutral position is improved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electromagnetically driven valve for an internal combustion engine, which is an improved control method for an electromagnetically driven intake / exhaust valve for an internal combustion engine.

[0002]

2. Description of the Related Art The structure of an electromagnetically driven intake / exhaust valve device is disclosed in, for example, Japanese Patent Laid-Open No. 2000-234534 (FIG. 12).
As shown in FIG. 2), a valve 3 that opens and closes the intake (exhaust) port 2 is attached to the lower portion of the valve housing 1, and the valve 3 is held in a closed position by a closing spring 5 during the valve closing period. On the other hand, a plunger 6 is arranged above the valve shaft 4 of the valve 3 so as to be vertically movable, and
A movable iron core 7 is fixed to the plunger 6, and a close side coil 8 and an open side coil 9 are arranged at predetermined intervals on both upper and lower sides of the movable iron core 7. Then, during the valve closing period, a current is passed through the upper coil 8 on the closing side to adsorb and hold the movable iron core 7 on the valve closing side (upper side), and the plunger 6 is opened.
Hold on the valve closing side (upper side) against 0. After that, when opening the valve, the current of the upper closed coil 8 is shut off, the current is passed through the lower open coil 9, and the movable iron core 7 is adsorbed and held on the valve open side (lower side). The plunger 6 pushes the valve shaft 4 downward against the closing spring 5 to hold the valve 3 in the open state.

One of the major technical problems to be solved in putting this electromagnetically driven intake / exhaust valve device into practical use is the collision noise when the valve 3 is seated on the valve seat 11 of the intake (exhaust) port 2. (Sitting sound) is reduced to reduce noise. To realize this, Japanese Patent Laid-Open No. 2000-23453
In Japanese Patent No. 4 publication, a position sensor 12 that detects the position of the valve 3 (valve lift amount) and a speed sensor 13 that detects the speed of the valve 3 are provided, and the position of the valve 3 detected by the position sensor 12 (valve lift amount). The target valve speed is set in accordance with the above, and the actual valve speed detected by the speed sensor 13 is compared with the target valve speed to control the current value to be applied to each coil 8 and 9, so that the valve 3 is seated. The seating sound is reduced by controlling the actual valve speed (seating speed) when seated at No. 11 to be substantially zero.

[0004]

By the way, when the valve 3 is closed from the valve opening position, the spring force in the valve opening direction by the opening side spring 10 and the spring force in the valve closing direction by the closing side spring 9 are in the middle thereof. There is a neutral valve lift amount (hereinafter referred to as "neutral position") that balances the forces, and the acting direction of the combined spring force of both springs 9 and 10 is reversed by 180 ° with this neutral position as a boundary. Therefore, when controlling the energizing currents of the coils 8 and 9, it is necessary to judge and control the valve lift amount with reference to the neutral position, but the neutral position is not constant and does not change. Due to factors such as wear and thermal expansion, deterioration of the springs 9 and 10 over time, and changes in sliding resistance,
The neutral position fluctuates. If the neutral position fluctuates, it is desirable to change the target valve speed and the control gain accordingly.However, the conventional control technique described above does not consider the fluctuation of the neutral position at all, so the neutral position fluctuates. However, the target valve speed and the control gain are set to the same values as when the neutral position does not change. for that reason,
The seating speed of the valve 3 varies due to the change of the neutral position, and the seating sound reducing effect is reduced, or the speed of the valve 3 becomes 0 before the valve 3 is seated on the valve seat 11, and the valve 3 is seated. There is a possibility of catching mistakes in which you go back without doing so.

The present invention has been made in view of the above circumstances, and therefore an object thereof is to make it possible to reflect the fluctuation of the neutral position in the control of the electromagnetically driven valve, and to prevent the influence of the fluctuation of the neutral position. An object of the present invention is to provide a control device for an electromagnetically driven valve of an internal combustion engine, which can surely reduce the seating sound without receiving it and can prevent a catch error due to a change in the neutral position.

[0006]

In order to achieve the above object, a control device for an electromagnetically driven valve for an internal combustion engine according to claim 1 of the present invention is provided with a spring force in a valve opening direction by a spring on the opening side and a spring on the closing side. The neutral position estimation means for estimating the neutral valve lift amount (neutral position), which is balanced with the spring force in the valve closing direction, is estimated by the neutral position estimation means during the operation of the internal combustion engine. The energization control of the electromagnetic actuator that drives the valve based on the neutral position is corrected by the correction means. By doing this, even if the neutral position fluctuates due to thermal expansion of each part due to temperature rise and changes in sliding resistance during operation of the internal combustion engine, it is possible to estimate the fluctuation of the neutral position during operation of the internal combustion engine. It can be reflected in the control of the electromagnetically driven valve, and it is possible to prevent the seating speed of the valve from fluctuating due to fluctuations in the neutral position during operation of the internal combustion engine, and it is possible to reliably reduce the seating sound and to make the valve seat on the valve seat. The valve speed is zero before seating
It is possible to prevent a catch error from occurring.

In this case, various methods are conceivable for estimating the neutral position. For example, as claimed in claim 2, a motion equation for analyzing the motion state of a movable part such as a valve during operation of the internal combustion engine is used. You may make it estimate a neutral position. In this way, even if the neutral position fluctuates during operation of the internal combustion engine due to thermal expansion of each component due to temperature rise of the internal combustion engine during operation of the internal combustion engine or changes in sliding resistance, etc. The fluctuation can be estimated, and the fluctuation of the neutral position during the operation of the internal combustion engine can be reflected in the control of the electromagnetically driven valve.

Further, as described in claim 3, when the valve driving speed is almost maximum, it is preferable to estimate the neutral position by using the valve lift amount detected by the valve lift amount detecting means. In other words, the valve drive speed has a characteristic that it becomes maximum near the neutral position. Therefore, if the neutral position is estimated using the valve lift amount detected when the valve drive speed is almost maximum, the neutral position can be accurately calculated. Can be estimated.

In this case, the valve drive speed may be detected by a speed sensor as in the conventional electromagnetically driven valve control device described above. However, as in claim 4, the valve lift amount is detected. The valve drive speed may be obtained by differentiating the valve lift amount detected by the means with respect to time. By doing so, the speed sensor can be omitted and the demand for cost reduction can be satisfied.

Further, as described in claim 5, the valve drive speed may be obtained by filtering the value obtained by differentiating the valve lift amount detected by the valve lift amount detecting means with respect to time. By doing so, it is possible to accurately obtain the valve drive speed by eliminating the influence of noise and quantization problems.

By the way, when the neutral position is estimated by using a motion equation for analyzing the motion state of a movable part such as a valve during the operation of an internal combustion engine, the motion equation is defined by the inertial force of the movable part such as the valve and each spring. In addition to the spring force, it is necessary to consider the electromagnetic force of the electromagnetic actuator and the cylinder pressure. However, it is not always easy to accurately detect or estimate the electromagnetic force of the electromagnetic actuator or the in-cylinder pressure that changes momentarily when the valve is driven. In addition, it is possible to calculate the electromagnetic force of the electromagnetic actuator from information such as the current value and the valve lift amount. However, in addition to the large calculation load and memory capacity, the detection error and noise of the sensor that detects the current value, etc. Since it is included, it is not easy to accurately calculate the electromagnetic force of the electromagnetic actuator.

Therefore, it is preferable to estimate the neutral position by using data sampled in an operating state in which the electromagnetic force of the electromagnetic actuator and the in-cylinder pressure are known as in the sixth aspect. In this way, only the inertial force of moving parts (= mass of moving parts x acceleration) and the spring force of each spring are unknown among the main external forces to be incorporated in the equation of motion, and the unknown external force in the equation of motion is unknown. Therefore, the neutral position can be calculated easily and accurately from the equation of motion. The acceleration used when calculating the inertial force of the movable part may be detected by an acceleration sensor, or may be obtained by differentiating the valve drive speed with respect to time. Furthermore,
If the acceleration is obtained by filtering the value obtained by differentiating the valve driving speed with time, the acceleration can be obtained with high accuracy while eliminating the influence of noise and quantization problems.

Further, as described in claim 7, data used for estimating the neutral position may be sampled while the electromagnetic actuator is not energized. Since the electromagnetic force of the electromagnetic actuator is 0 while the electromagnetic actuator is not energized, the neutral position can be calculated without being affected by the electromagnetic force of the electromagnetic actuator.

By the way, the cause of the change of the neutral position is, as described above, the wear and thermal expansion of each component, the deterioration of the spring with time, the change of the sliding resistance, and the like, which all gradually change over a long period of time. Therefore, it is not necessary to estimate the neutral position every cycle and immediately reflect it in the energization control. Further, during the period in which the valve is driven, the calculation load is large because the energization control of the electromagnetic actuator is performed, and thus there may be no room to calculate the neutral position.

In consideration of these circumstances, as in claim 8, the data used for estimating the neutral position is periodically sampled and stored in the memory while the valve is being driven. The neutral position may be estimated based on the data stored in the memory after the driving is completed. With this configuration, the neutral position can be calculated with a margin when the calculation load is small after the valve has been driven, and the calculation load can be prevented from becoming overloaded.

When the exhaust valve is opened from the closed position and the data used for estimating the neutral position of the exhaust valve is sampled, the lift amount of the exhaust valve varies within the range of the neutral position. Until the electromagnetic actuator is exceeded, energize the electromagnetic actuator, drive the exhaust valve in the valve opening direction only by the resultant force of the opening side spring and closing side spring, and forcibly reduce the load on the internal combustion engine. May be. With this configuration, when sampling the data used for estimating the neutral position when the exhaust valve is driven to open so that the influence of the in-cylinder pressure becomes large, the electromagnetic force of the electromagnetic actuator is reduced to 0 in order to make the electromagnetic force of the electromagnetic actuator zero. Even if the exhaust valve is driven in the valve opening direction only by the resultant force of both springs after the energization is stopped, the load of the internal combustion engine is forcibly reduced to provide resistance to the valve opening operation of the exhaust valve. The in-cylinder pressure can be reduced. As a result, the exhaust valve can be driven in the valve opening direction almost in the same way as in the normal state, and while preventing the occurrence of a catch error that the exhaust valve is not held in the valve open position, The data used for estimation can be sampled.

When the intake valve is opened from the closed position and data used for estimating the neutral position of the intake valve is sampled, the electromagnetic valve is stopped and the intake valve is stopped. Is driven only by the combined force of the open side spring and the close side spring, causing a catch error that the intake valve is not held in the open position, and reducing the torque of the internal combustion engine caused by the decrease in intake air amount due to this catch error. It may be absorbed by a continuously variable transmission. In other words, in order to sample the data used to estimate the neutral position when opening the intake valve,
If the electromagnetic force of the electromagnetic actuator is set to 0 by stopping the power supply to the electromagnetic actuator, a catch error will occur,
The intake valve opening time and lift amount are insufficient, and the intake air amount decreases, causing torque down.However, the torque down is absorbed by the continuously variable transmission so that the driver does not feel torque shock. Complete.

Alternatively, when the intake valve is opened from the closed position and the data used for estimating the neutral position of the intake valve is sampled, the energization to the electromagnetic actuator is stopped and the catch is obtained. The opening of the throttle valve may be increased in order to prevent a decrease in intake air amount due to this catch error. With this configuration, when the intake valve is driven to open, the opening of the throttle valve is controlled even if the electromagnetic actuator is de-energized and a catch error occurs in order to sample the data used to estimate the neutral position. By increasing the amount, it is possible to suppress a decrease in the intake air amount due to a catch error, and it is possible to suppress torque reduction.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. First, the structure of the entire electromagnetically driven valve device will be described with reference to FIGS. 1 and 2. An intake (or exhaust) port 22 is formed in the lower portion of the valve housing 21, and an annular valve seat 23 is attached to the opening peripheral edge of the port 22. A valve shaft 25 that supports the valve 24 is slidably supported in the vertical direction through a bearing member 26 in the center of the valve housing 21.
The vertical movement causes the valve 24 to open and close the port 22.
The closing side spring 29 is sandwiched between the spring receiving member 27 fitted and fixed to the upper portion of the valve shaft 25 and the bottom surface portion of the spring accommodating chamber 28 in the valve housing 21, and the valve is pushed up by the closing side spring 29. The shaft 25 is urged toward the valve closing side (upper side), and during the valve closing, the valve 24 is pushed by the pushing force of the closing side spring 26.
Is kept closed.

On the other hand, an electromagnetic actuator 30 is attached to the upper side of the valve housing 21. The housing of the electromagnetic actuator 30 is composed of a non-magnetic upper housing 31 and a non-magnetic lower housing 32.
The closed-side core 34 to which is mounted and the open-side core 36 to which the open-side coil 35 is mounted are assembled so as to face each other with a predetermined gap. A non-magnetic annular spacer 37 for keeping a constant distance therebetween is sandwiched between the closed side core 34 and the open side core 36, and a flat plate-shaped movable iron core 38 is vertically moved inside the annular spacer 37. It is freely accommodated. A plunger 39 is vertically penetrated and fixed to the center of the movable iron core 38. The plunger 39 has through holes 40 and 41 formed in the centers of the housings 31 and 32.
It is slidably supported in the vertical direction.

A spring case 44 accommodating an open side spring 43 is attached to a cylindrical portion 42 formed at the center of the upper surface of the upper housing 31. In the spring case 44, a spring receiving member 45 fixed to the upper end of the plunger 39 is housed so as to be vertically movable,
The open side spring 43 is sandwiched between the spring receiving member 45 and the upper surface of the spring case 44, and the plunger 3 is pushed by the pressing force of the open side spring 43.
9 is biased to the valve opening side (lower side).

At the time of closing the valve, a drive current is passed through the upper closing coil 33 to attract and hold the movable iron core 38 to the lower surface of the closing core 34, as shown in FIG. In this state, a clearance 46 for absorbing the thermal expansion of the plunger 39 and the valve shaft 25 is formed between the plunger 39 and the valve shaft 25.
The valve closed state of No. 4 is held by the pushing force of the closing side spring 26. While the valve 24 is closed, the holding current continues to flow through the upper closed coil 33.

On the other hand, when opening the valve 24 from the closed state, first, the holding current of the upper closed coil 33 is cut off to release the attraction state between the closed core 34 and the movable core 38. To do. As a result, the movable iron core 38 and the plunger 39 are pushed down by the spring force of the open side spring 43,
Further, the plunger 39 pushes the valve shaft 25 downward against the closing side spring 29. Until the valve lift amount exceeds the neutral position described later, the opening side spring 43
Since the spring force of is larger than the spring force of the closing spring 29, even if a drive current is not applied to the lower opening coil 35,
The valve shaft 25 is pushed down against the closing side spring 29 by the plunger 39. Then, from the middle of this valve opening operation, a drive current is passed through the lower opening side coil 35,
As shown in FIG. 2, the movable iron core 38 is adsorbed and held on the upper surface of the open side core 36, and the valve shaft 25 is pushed down by the plunger 39 against the close side spring 29 to hold the valve 24 in the open state. While the valve 24 is open, the holding current continues to flow through the lower open coil 35.

A lift sensor 47 (valve lift amount detecting means) for detecting the valve lift amount is attached to the spring case 44. A gap sensor is used as the lift sensor 47, and the valve lift amount is detected by detecting the gap between the lift sensor 47 and the spring receiving member 45 that moves up and down together with the plunger 39. . The output signal of the lift sensor 47 is, as shown in FIG.
It is amplified in 8 and input to an engine control circuit (hereinafter referred to as “ECU”) 49.

The ECU 49 is mainly composed of a microcomputer, and has a crank angle sensor 50, a cooling water temperature sensor 51, an intake air amount sensor 52, and an intake air temperature sensor 5.
The output signals of various sensors for detecting the engine operating state such as 3 are read, and the fuel injection amount and the ignition timing are controlled according to the engine operating state by each program for engine control, and the opening / closing timing of the valve 24 and the driving speed are set. The calculation is performed and a control signal corresponding to the calculated value is output to the drive circuit 54 to control the energization of the coils 33 and 35 of the electromagnetic actuator 30. The function of the ECU 49 serves as an energization control unit in the claims.

Further, the ECU 49 has a built-in ROM.
By executing the programs of FIGS. 9 to 11 stored in the (storage medium), which will be described later, the neutral position of the valve 24 is calculated using a motion equation that analyzes the motion state of a movable part such as the valve 24 during engine operation. To estimate. Here, the neutral position is a neutral valve lift amount in which the spring force of the opening side spring 43 in the valve opening direction and the spring force of the closing side spring 29 in the valve closing direction are balanced.

Next, a method of estimating the neutral position will be described. A spring-mass system equation of motion is adopted as the equation of motion for analyzing the moving state of the movable parts such as the valve 24. The equation of motion of the spring-mass system is expressed by the following equation. F = m · d ² x / dt ² + c · dx / dt + k · x (1) F: External force acting on the spring-mass system m: Mass of moving parts x: Valve lift k: Both springs 29, 43 Composite spring constant c: Viscosity coefficient d ² x / dt ² : Acceleration dx / dt: Velocity where m · d ² x / dt ² is the inertial force of the movable part, and c ·
dx / dt is a viscous resistance force of the lubricating oil of the sliding portion, and k · x is a combined spring force of both springs 29 and 43.

The external force F acting on the spring-mass system is expressed by the following equation. F = Fe-Fer-Fp-Ff-k · x ₀ (2) Fe: Electromagnetic force of both coils 33, 35 Fer: Residual electromagnetic force Fp: Force due to cylinder pressure Ff: Dry friction force k: Both springs Synthetic spring constant x _{0 of} 29, 43: deviation amount of neutral position Here, the electromagnetic force Fe is generated when a current is applied to the coils 33, 35, and the residual electromagnetic force Fer is generated by the coil 33,
It is generated by the current induced immediately after the current of 35 is cut off.

The following equation is derived from the above equations (1) and (2). Fe −Fer −Fp −Ff −k · x ₀ = m · d ² x / dt ² + c · dx / dt + k · x (3) −k · x ₀ = m · d ² x / dt ² + c · dx / dt + k * x- (Fe-Fer-Fp-Ff) (4) The following equation is derived from the equation (4). _{x 0 = - {m · d} 2 x / dt 2 + c · dx / dt + k · x- (Fe -Fer -Fp -Ff} / k ...... (5)

In the above equation (5), m, c, k, Ff
Can be measured or calculated in advance, so that unknown data changes d ² x / d while the valve 24 is driven.
t ² , dx / dt, x, Fe, Fer, Fp. If all of these data are known, the shift amount x ₀ of the neutral position can be calculated from the above (5).

Here, as the valve lift amount x, the detection value of the lift sensor 47 may be used, and the speed dx / dt.
Can be obtained by differentiating the valve lift amount x with time, and similarly, the acceleration d ² x / dt ² can be obtained by differentiating the speed dx / dt with respect to time.

If the valve lift amount x is detected under the condition of Fe = Fer = Fp = 0, the shift amount x ₀ of the neutral position can be calculated by the following equation. _{x 0 = - (m · d} 2 x / dt 2 + c · dx / dt + k · x + Ff) / k ...... (6)

If the valve lift amount x and the force Fp due to the in-cylinder pressure are detected or calculated under the condition of Fe = Fer = 0,
The shift amount x ₀ of the neutral position can be calculated by the following formula. _{x 0 = - (m · d} 2 x / dt 2 + c · dx / dt + k · x + Fp + Ff) / k ...... (7)

An example of the case where the neutral position is estimated using the above-described equation of motion is shown in FIG. Figure 4
The lift sensor 47 detects the valve lift amount x, and differentiates the valve lift amount x with time to obtain the speed dx / dt.
Further, this velocity dx / dt is differentiated with respect to time to accelerate d ² x
/ Dt ² is obtained and the neutral position is estimated. At this time, the time differentiation may be performed by hardware using a differentiating circuit or may be performed by software by the arithmetic processing of the ECU 49. In the example of FIG. 4, the output of the lift sensor 47 is processed by a differentiating circuit to obtain the speed dx / dt, and the speed dx / dt is further calculated.
The acceleration d ² x / dt ² is obtained by time-differentiating x / dt by the arithmetic processing of the ECU 49.

However, if the velocity dx / dt is simply differentiated with respect to time, the acceleration d will be affected by noise and quantization problems.
^{Since 2} x / dt ² rattles, the estimated neutral position also rattles. To solve this problem, as shown in FIG. 5, it is advisable to calculate the acceleration d ² x / dt ² by filtering the value obtained by differentiating the velocity dx / dt with respect to time. Since this filtering process eliminates the influence of noise and quantization problems, the change characteristic of the acceleration d ² x / dt ² becomes a smooth curve, the estimated neutral position does not rattle, and the estimation accuracy of the neutral position is improved. To do. Note that the filtering process may use an arithmetic method such as a smoothing process (first-order delay process) or an averaging process, or a digital filter such as an FIR filter.

FIG. 6 shows the result of estimating the neutral position for each of them by intentionally shifting the neutral position. Further, FIG. 7 is a graph in which the estimated neutral position calculated at the maximum velocity position estimated to be near the neutral position is plotted.

Since the velocity dx / dt has a characteristic that it becomes maximum near the neutral position, if the neutral position is estimated using the data detected at the maximum velocity position, the neutral position can be accurately estimated. In the present experimental example, as shown in FIG. 7, the estimated neutral position tended to be offset from the true value by a substantially constant value, but this offset occurred because the acceleration d ² x / dt ² was filtered. It seems to have been done. Therefore, if the true value of the neutral position is measured in the manufacturing process and the offset amount is grasped in advance, the neutral position can be accurately estimated by correcting the offset amount from the estimation result of the neutral position.

Incidentally, as shown in FIG. 4, the acceleration d ² x / dt ² obtained by differentiating the speed dx / dt with time is unstable because the resolution of the lift sensor 47 and the resolution of the A / D converter are insufficient. Therefore, if these resolutions are increased, it is considered that there is no need to perform the filtering process and the offset of the estimated neutral position does not occur.

Although the equation of motion used for estimating the neutral position includes the electromagnetic force Fe, it is not always easy to accurately detect or estimate the electromagnetic force Fe which changes momentarily when the valve 24 is driven. Also, this electromagnetic force F
Although it is possible to calculate e from information such as the current value and the valve lift amount, since the calculation load and memory capacity of the ECU 49 become large, and the detection error and noise of the sensor for detecting the current value are included, It is difficult to accurately calculate the electromagnetic force Fe.

Therefore, in this embodiment, the coils 33, 3 are
The valve lift amount x used for estimating the neutral position is detected during the period in which the valve 5 is not energized, but normally, in order to prevent a catch error, one of the valve lifts is relatively early during the opening / closing operation of the valve 24. The coil is energized. For example, FIG. 8 shows the relationship between the energizing current and the valve lift amount when the exhaust valve 24 is opened from the closed position, but normally, in order to prevent a catch error, the valve of the exhaust valve 24 is Energization to the open side coil 35 is started before the lift amount reaches the neutral position. Under this condition, in the vicinity of the neutral position where the speed dx / dt is the maximum, the open side coil 35 is already energized and the electromagnetic force Fe is generated. Therefore, from the data detected at the time when the speed dx / dt is the maximum. When trying to estimate the neutral position, the electromagnetic force Fe cannot be ignored.

Therefore, in the present embodiment, the exhaust valve 24
When sampling the data used for estimating the neutral position of the exhaust valve 24 during the opening operation of the exhaust valve 24, the energization to the open side coil 35 is stopped until the lift amount of the exhaust valve 24 exceeds the fluctuation range of the neutral position. The valve 24 is driven in the valve opening direction only by the resultant force of the opening side spring 43 and the closing side spring 29. As a result, in the vicinity of the neutral position where the speed dx / dt is maximum, the open side coil 35 is not energized yet, so the neutral position of the exhaust valve 24 is estimated from the data detected near the neutral position where the speed dx / dt is maximum. In doing so, the electromagnetic force Fe can be ignored.

However, during the valve opening operation of the exhaust valve 24, the in-cylinder pressure acts as a resistance force that hinders the valve opening operation of the exhaust valve 24. Therefore, the timing of starting energization of the open side coil 35 is delayed in order to estimate the neutral position. If so, a catch error that the exhaust valve 24 cannot be held at the open position is likely to occur. Therefore, in the present embodiment, the engine load (for example, the intake air amount, the fuel injection amount) is forcibly reduced in response to the delay of the energization start timing to the open side coil 35, and the in-cylinder pressure is reduced. . As a result, even if the open side coil 35 is not energized until the lift amount of the exhaust valve 24 exceeds the fluctuation range of the neutral position in order to estimate the neutral position, a catch error can be prevented and the exhaust valve 24 can be secured. Can be held in the valve open position.

Further, in this embodiment, in order to detect the data used for estimating the neutral position of the intake valve 24 during the opening operation of the intake valve 24, the energization of the open side coil 35 is stopped and the intake valve 24 is opened. It drives in the valve opening direction only by the resultant force of the opening side spring 43 and the closing side spring 29. As a result, when estimating the neutral position of the intake valve 24, the electromagnetic force Fe can be ignored, but since the energization to the open side coil 35 is stopped, the intake valve 24 is not held at the open position. Occurs. Due to this catch error, the closing side coil 33 is energized at the timing when the intake valve 24 returns to the closing side by the spring force, and the intake valve 24 is prevented from being sucked on the closing side and becoming uncontrollable. However, due to this operation, the valve opening time / lift amount of the intake valve 24 is insufficient, the intake air amount is reduced, and the torque of the engine is reduced, so that the driver feels a torque shock as it is. Therefore, in the present embodiment, the torque shock is alleviated by either of the following two methods.

In a vehicle equipped with a continuously variable transmission, the torque reduction due to a catch error that occurs when estimating the neutral position of the intake valve 24 is absorbed by the continuously variable transmission so that the driver does not feel torque shock. To do so.

Alternatively, in a vehicle equipped with an electronically controlled throttle valve, the throttle valve opening is increased in order to suppress a decrease in intake air amount due to a catch error that occurs when estimating the neutral position of the intake valve 24. Let As a result, it is possible to suppress a decrease in the intake air amount due to a catch error and prevent torque reduction.
In a vehicle equipped with both a continuously variable transmission and an electronically controlled throttle valve, in order to more effectively mitigate the torque shock due to a catch error, the throttle valve control and the continuously variable transmission control described above are used. It goes without saying that may be used together.

By the way, the cause of the change of the neutral position is wear and thermal expansion of each component, deterioration of the springs 29 and 43 over time, change of sliding resistance, etc., and these are changes that appear little by little over a long period of time. Therefore, it is not necessary to estimate the neutral position every cycle and immediately reflect it in the energization control of the coils 33 and 35. Further, during the period in which the valve 24 is driven to be opened and closed, the calculation load of the ECU 49 becomes large because the energization control of the coils 33 and 35 is performed, and therefore there may be no room to calculate the neutral position.

Therefore, in this embodiment, the data used for estimating the neutral position is periodically sampled during the period in which the valve 24 is driven and stored in a memory (not shown) such as the RAM of the ECU 49. After the driving of the valve 24 is finished, the neutral position is estimated based on the data stored in the memory. In this way, the neutral position can be calculated with a margin when the calculation load of the ECU 49 is small after the driving of the valve 24 is finished, and the calculation load can be prevented from becoming overloaded. The above-described estimation of the neutral position is executed by the ECU 49 according to the programs of FIGS. 9 to 11. The processing contents of each of these programs will be described below.

[Neutral Position Estimation Program] The neutral position estimation program shown in FIG. 9 has a predetermined calculation cycle (for example, several 10 μm).
It is activated in s) and functions as a neutral position estimating means in the claims. When this program is started, first, at step 101, it is judged whether or not there is a request for neutral position estimation of the valve 24. If there is no request for neutral position estimation, this program is executed without performing the subsequent processing. finish. As mentioned above, the reason why the neutral position changes is
It is not necessary to estimate the neutral position every cycle because it is a change that gradually wears out over a long time due to wear and thermal expansion of each part, deterioration of the springs 29 and 43 over time, and so on. The neutral position may be estimated at the time when it is expected that the neutral position may fluctuate based on the distance traveled from the time of estimation and the cooling water temperature.

If it is determined in step 101 that there is a request for neutral position estimation, the process proceeds to step 102, it is determined whether the valve 24 is being driven (opening / closing operation), and the valve 24 is driven. If it is medium, the routine proceeds to step 103, where the valve lift amount x detected by the lift sensor 47 and
The speed dx / dt obtained by time differentiating the valve lift amount x with a differentiating circuit is stored in the memory, and further, this speed dx
The value obtained by time-differentiating / dt is filtered and the acceleration d ²
Calculate x / dt ² and store in memory.

After this, the routine proceeds to step 104, where the valve 2
It is determined whether or not it is the neutral position calculation timing after the end of the driving of 4, and if the neutral position calculation timing has not been reached yet, the present program is terminated without calculating the neutral position. Accordingly, while the valve 24 is being driven, the data x and dx / d used for estimating the neutral position at a predetermined calculation cycle.
Only t, d ² x / dt ² is sampled.

Thereafter, when the drive of the valve 24 is completed and the neutral position calculation timing is reached, step 104
In step 105, the data x, dx / dt, d ² x / dt stored in the memory are determined.
² is read, and in the next step 106, the shift amount x ₀ of the neutral position is calculated using the above-described equation of motion.

The ECU 49 corrects the target valve speed and the control gain when the valve 24 is driven on the basis of the neutral position deviation amount x ₀ thus obtained, and determines the neutral position deviation amount x ₀ to the coil 33, This is reflected in the energization control of 35. The function of the ECU 49 serves as a correcting unit in the claims.

[Method 1] The exhaust valve control program of FIG. 10 is started every predetermined time or every predetermined crank angle.
First, at step 201, it is judged whether or not there is a request for estimating the neutral position of the exhaust valve 24. If there is no request for estimating the neutral position of the exhaust valve 24, the routine proceeds to step 202, where normal exhaust valve control is executed. Thus, for example, when the exhaust valve 24 is driven to open, as shown in FIG. 8, the energization of the open side coil 35 is started before the lift amount of the exhaust valve 24 exceeds the neutral position, and the electromagnetic force causes the cylinder to move. The exhaust valve 24 is driven in the valve opening direction against the internal pressure to prevent a catch error, and the exhaust valve 24 is securely adsorbed and held in the valve opening position. At this time, the target valve speed and control gain of the exhaust valve 24 are corrected based on the previously estimated neutral position deviation amount x ₀ , and the neutral position deviation amount x ₀ is reflected in the energization control of the open-side coil 35. The same control is performed when the exhaust valve 24 is closed.

On the other hand, in step 201, the exhaust valve 24
If it is determined that there is a request for neutral position estimation, the process proceeds to step 203 and the engine load (for example, intake air amount,
The fuel injection amount) is forcibly reduced to reduce the in-cylinder pressure. Then, in the next step 204, the exhaust valve 24
It is determined whether or not the lift amount x has exceeded a predetermined amount, and the energization to the open side coil 35 is stopped until the lift amount x of the exhaust valve 24 exceeds the predetermined amount (step 205). Here, the predetermined amount is set to an amount slightly exceeding the variation range of the neutral position. As a result, during the opening drive of the exhaust valve 24, until the lift amount x of the exhaust valve 24 exceeds the true neutral position, the open side coil 35 is not energized and a predetermined calculation is performed by the neutral position estimation program of FIG. Data x, dx / dt used for estimating the neutral position of the exhaust valve 24 in a cycle,
Only d ² x / dt ² sampling is performed.

After that, when the lift amount x of the exhaust valve 24 exceeds a predetermined amount, it is determined to be "Yes" in step 204, the process proceeds to step 206, and the energization to the open side coil 35 is started, and its electromagnetic The exhaust valve 24 is driven in the valve opening direction by a force against the cylinder pressure to prevent a catch error, and the exhaust valve 24 is securely adsorbed and held in the valve opening position. At this time, the target valve speed and control gain of the exhaust valve 24 are corrected based on the previously estimated neutral position deviation amount x ₀ , and the neutral position deviation amount x ₀ is reflected in the energization control of the open-side coil 35.

[Method 2] The intake valve control program of FIG. 11 is started every predetermined time or every predetermined crank angle.
First, at step 301, it is determined whether or not there is a request for estimating the neutral position of the intake valve 24. If there is no request for estimating the neutral position of the intake valve 24, the routine proceeds to step 302, where normal intake valve control is executed. With this, for example, when the intake valve 24 is driven to open, the energization to the open side coil 35 is started at a relatively early timing, the catching error is prevented by the electromagnetic force, and the intake valve 24 is reliably brought to the open position. Adsorb and hold. At this time, the target valve speed and the control gain of the intake valve 24 are corrected based on the previously estimated neutral position deviation amount x ₀ , and the neutral position deviation amount x ₀ is reflected in the energization control of the open-side coil 35. The same control is performed when the intake valve 24 is closed.

On the other hand, in step 301, the intake valve 24
If it is determined that there is a request for the neutral position estimation, the process proceeds to step 303, the energization to the open side coil 35 is stopped when the intake valve 24 is driven to open, a catch error occurs, and the next step At 304, the throttle opening is increased, and then the closing side coil 33 is energized at the timing when the intake valve 24 returns to the closing side due to the spring force, and the closing side coil 33 catches again (step 305). In this case, a decrease in intake air amount due to a catch error can be suppressed by increasing the throttle opening, and torque down can be suppressed so that the driver does not feel torque shock. At this time, in a vehicle equipped with a continuously variable transmission,
The torque reduction due to a catch error may be absorbed by the continuously variable transmission so that the driver does not feel the torque shock. In this way, when the intake valve 24 is driven to open, the energization to the open side coil 35 is stopped, and the data used to estimate the neutral position of the intake valve 24 at a predetermined calculation cycle by the neutral position estimation program of FIG. x, d
Only x / dt and d ² x / dt ² are sampled.

In the present embodiment described above, the neutral position is estimated during operation of the engine by using the equation of motion for analyzing the motion state of the moving parts such as the valve 24. Therefore, the temperature of the engine during the operation of the engine is estimated. Even if the neutral position fluctuates during engine operation due to thermal expansion of each part due to ascent, changes in sliding resistance, etc., it is possible to estimate the fluctuation of the neutral position during engine operation. It can be reflected in the control of 24. As a result, the seating speed of the valve 24 can be prevented from varying due to the change in the neutral position, the seating sound can be reliably reduced, and the requirement for low noise can be satisfied, and the valve 24 seats on the valve seat 23. It is possible to prevent a catch error from occurring before the speed of the valve 24 becomes 0, and it is possible to perform highly reliable variable valve control.

Further, in this embodiment, the lift sensor 47 is used.
Differentiate the valve lift detected in step 1 to obtain the valve drive speed, and further differentiate the valve drive speed with time to obtain the acceleration, so the speed sensor and acceleration sensor can be omitted and the number of sensors can be reduced. The cost increase can be suppressed. In addition, since the value obtained by differentiating the valve driving speed with time is filtered to obtain the acceleration, it is possible to obtain the acceleration with high accuracy by eliminating the influence of noise and quantization problems.

Further, in the present embodiment, since the energization of the electromagnetic actuator 30 is stopped and the data used for estimating the neutral position is sampled, the neutral force is not affected at all and the neutral force is exerted. The position can be calculated, the calculation of the neutral position is facilitated, and the calculation accuracy of the neutral position can be improved.

Moreover, the data used for estimating the neutral position is periodically sampled and stored in the memory while the valve 24 is driven, and the data stored in the memory after the valve 24 is driven is changed to the data stored in the memory. Since the neutral position is estimated on the basis of the calculation, the neutral position can be calculated with a margin when the calculation load of the ECU 49 after driving of the valve 24 is small, and the calculation load of the ECU 49 becomes overloaded. Can be prevented.

However, since the CPU of the ECU 49 has a large arithmetic processing capacity, the energization control of the coils 33 and 35, the sampling of data, and the calculation of the estimation of the neutral position are performed in parallel while the valve 24 is being driven. Needless to say, if there is a margin, the calculation of the neutral position estimation may be executed in parallel while the valve 24 is being driven.

Further, in this embodiment, the data used for estimating the neutral position is sampled during the valve opening drive of the valve 24, but the data used for estimating the neutral position is sampled during the valve closing drive of the valve 24. It may be done.

Immediately after the ignition switch is turned on and before the starter is energized (immediately before the start of engine operation), the valve lift amount detected by the lift sensor 47 is used as the initial value of the neutral position, and the equation of motion is calculated immediately after the start of engine operation. The calculated neutral position is compared with the initial value of the neutral position detected by the lift sensor 47 immediately before the start of engine operation, and the coefficient of the equation of motion is corrected so that the difference between the two falls within an appropriate range. May be.

In the present embodiment, the lift sensor 47 is arranged above the electromagnetic actuator 30 to detect the gap between the lift sensor 47 and the spring receiving member 45 which moves up and down together with the plunger 39. Thus, the valve lift amount is detected, but a lift sensor is arranged below the valve 24 so that the lift amount of the valve 24 is directly detected, or the lift amount of the plunger 39 (or the valve shaft 25) is detected. Place a lift sensor around,
The vertical movement amount of the plunger 39 (or the valve shaft 25) may be detected as the valve lift amount.

In this embodiment, both the intake valve and the exhaust valve are electromagnetically driven valves, but only one of them may be electromagnetically driven valves.

In addition, it is needless to say that the present invention can estimate the neutral position during engine operation regardless of whether the intake valve (or the exhaust valve) is closed to open or open to closed. .

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a closed state of an electromagnetically driven valve device according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a state when the electromagnetically driven valve device is opened.

FIG. 3 is a block diagram schematically showing a circuit configuration of a control system.

FIG. 4 is a diagram showing a relationship between a valve lift amount, velocity, acceleration, and an estimated neutral position when a filter is not used.

FIG. 5 is a diagram showing a relationship among a valve lift amount, a velocity, an acceleration, and an estimated neutral position when a filter is used.

FIG. 6 is a diagram showing a calculation characteristic of an estimated neutral position.

FIG. 7 is a diagram for explaining the estimation accuracy of the neutral position when the neutral position is estimated near the maximum velocity position.

FIG. 8 is a diagram illustrating a relationship between a valve lift amount and a current.

FIG. 9 is a flowchart showing a processing flow of a neutral position estimation program.

FIG. 10 is a flowchart showing the flow of processing of an exhaust valve control program.

FIG. 11 is a flowchart showing a flow of processing of an intake valve control program.

FIG. 12 is a longitudinal sectional view showing a state of a conventional electromagnetically driven valve device when the valve is closed.

[Explanation of symbols]

22 ... Port, 23 ... Valve seat, 24 ... Valve, 25 ... Valve shaft, 29 ... Closing side spring, 30 ... Electromagnetic actuator, 33 ... Closing side coil, 34 ... Closing side core, 35 ... Open side coil, 36 ... Open Side core, 38 ... Movable iron core, 39 ... Plunger, 43 ... Open side spring, 47 ... Lift sensor (valve lift amount detecting means), 49 ... ECU (energization control means, neutral position estimating means, correcting means).

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16K 31/06 310 F16K 31/06 310A 320 320A (72) Inventor Akira Shibata 1-chome, Showa-cho, Kariya city, Aichi prefecture No. 1 in DENSO Co., Ltd. (72) Inventor Yurio Nomura 1-chome, Showa-cho, Kariya city, Aichi prefecture Denso Co., Ltd. (72) No. Fuwa Minoru, Toyota-cho, Aichi prefecture Toyota-cho, Toyota Motor Corporation Inner F-term (reference) 3G018 AB08 DA34 EA24 EA26 FA01 GA01 GA04 GA21 GA31 GA32 3G092 AA01 AA11 AB02 DA01 DA07 DC01 DG07 EA11 FA05 FA11 FA14 HA01Z HA04Z HE02Z HE03Z HE08Z PE01 PE01 PE09 PE01 PA01 PA01 PA01 PA01 PA01 PA01 PA01 PA01 PA01 LA01 PA01 LA01 PF08Z 3H106 DA08 DA11 DA25 DB02 DB26 DB32 DC02 DD07 DD09 EE20 EE27 FB02 FB07 GC03 KK17

Claims (11)

[Claims] 1. A valve for opening and closing an intake port or an exhaust port of an internal combustion engine, an opening side spring for urging the valve in a valve opening direction, a closing side spring for urging the valve in a valve closing direction, and an opening An electromagnetic actuator that drives the valve in the valve opening direction against the closing spring when the valve is opened, and drives the valve in the valve closing direction against the opening spring when the valve is closed, and detects the valve lift amount. Internal combustion engine provided with valve lift amount detection means, and energization control means for controlling energization to the electromagnetic actuator according to the valve lift amount detected by the valve lift amount detection means and the like to control the drive speed of the valve In the electromagnetically driven valve control device, the neutral force in which the spring force in the valve opening direction by the opening side spring and the spring force in the valve closing direction by the closing side spring are balanced. Neutral position estimation means for estimating a valve lift amount (hereinafter referred to as "neutral position") during operation of the internal combustion engine, and energization control of the electromagnetic actuator by the energization control means based on the neutral position estimated by the neutral position estimation means A control device for an electromagnetically driven valve for an internal combustion engine, comprising: 2. The neutral position estimating means estimates the neutral position by using a motion equation that analyzes a motion state of a movable part such as the valve during operation of an internal combustion engine. A control device for an electromagnetically driven valve of an internal combustion engine as described above. 3. The neutral position estimating means estimates the neutral position by using the valve lift amount detected by the valve lift amount detecting means when the driving speed of the valve becomes substantially maximum. An electromagnetically driven valve control device for an internal combustion engine according to claim 1 or 2. 4. The neutral position estimating means obtains the drive speed of the valve by differentiating the valve lift amount detected by the valve lift amount detecting means with respect to time. A control device for an electromagnetically driven valve of an internal combustion engine as described above. 5. The neutral position estimating means obtains the drive speed of the valve by filtering a value obtained by differentiating the valve lift amount detected by the valve lift amount detecting means with respect to time. A control device for an electromagnetically driven valve of an internal combustion engine as described above. 6. The neutral position estimating means estimates the neutral position using data sampled in an operating state in which the electromagnetic force of the electromagnetic actuator and the in-cylinder pressure are known. 6. A control device for an electromagnetically driven valve of an internal combustion engine according to any of 5. 7. The electromagnetic drive type internal combustion engine according to claim 6, wherein the neutral position estimating means samples data used for estimating the neutral position while the electromagnetic actuator is not energized. Valve control device. 8. The neutral position estimating means periodically samples the data used for estimating the neutral position while the valve is being driven and stores the data in a memory.
8. The control device for an electromagnetically driven valve for an internal combustion engine according to claim 1, wherein the neutral position is estimated based on the data stored in the memory after the driving of the valve is completed. 9. The energization control means controls energization of an electromagnetic actuator that drives an exhaust valve, and the neutral position estimating means opens the exhaust valve from a closed position to a neutral position of the exhaust valve. When sampling the data used for the estimation, the energization of the electromagnetic actuator is stopped until the lift amount of the exhaust valve exceeds the fluctuation range of the neutral position, and the exhaust valve is opened and closed. 9. The electromagnetically driven valve control for an internal combustion engine according to claim 6, wherein the valve is driven in the valve opening direction only by the resultant force with the spring and the load of the internal combustion engine is forcibly reduced. apparatus. 10. The present invention is applied to a vehicle equipped with a continuously variable transmission, wherein the energization control means controls energization to an electromagnetic actuator that drives an intake valve, and the neutral position estimating means closes the intake valve. When sampling the data used to estimate the neutral position of the intake valve by opening the intake valve, the electromagnetic actuator is stopped from being energized to open the intake valve only by the resultant force of the open side spring and the close side spring. Drive the valve in the valve opening direction to cause a catch error in which the intake valve is not held in the open position, and the continuously variable transmission absorbs the torque reduction of the internal combustion engine caused by the decrease in the intake air amount due to this catch error. An electromagnetically driven valve control device for an internal combustion engine according to any one of claims 6 to 9, wherein: 11. The invention is applied to a vehicle in which a throttle valve is provided in an intake passage of an internal combustion engine, the energization control means controls energization to an electromagnetic actuator that drives the intake valve, and the neutral position estimating means includes the intake air When sampling the data used to estimate the neutral position of the intake valve by opening the valve from the closed position, the energization of the electromagnetic actuator is stopped and the intake valve is opened and closed. The intake valve is driven in the valve opening direction only by the resultant force to cause a catch error that the intake valve is not held in the open position, and the opening of the throttle valve is increased to suppress a decrease in intake air amount due to this catch error. The control device for an electromagnetically driven valve for an internal combustion engine according to any one of claims 6 to 10, wherein